The Use of Biomarkers for the Early Detection of Vulnerable Atherosclerotic Plaques and Vulnerable Patients. A Review
Journal of Cardiovascular Emergencies, 2016, by Benedek, Theodora; Maurovich-Horváth, Pál; Ferdinandy, Péter; Merkely, Béla
The most severe consequence of atherosclerosis is coronary artery syndrome, often initiated by cleavage of unstable coronary plaque. New methods and techniques have been proposed to study various biomarkers as a platform for identifying diagnostic algorithms. In this article, they summarize recent research related to biomarkers used for the early detection of unstable, coronary plaques. Development of novel assays and imaging techniques has resulted in the advancement of biomarker technology, which allows the detection and classification of both vulnerable plaques and vulnerable patients. Complex risk-assessment models based on integration of imaging-derived biomarkers and different patient-specific information related to systemic biomarkers, has yet to be perfected.
The Endothelial Glycocalyx: A Review of the Vascular Barrier
by Alphonsus, C. S; Rodseth, R. N, Anaesthesia, 07/2014, Volume 69, Issue 7
The endothelial glycocalyx is an important part of the vascular barrier. The glycocalyx is intimately linked to the homoeostatic functions of the endothelium. Damage to the glycocalyx precedes vascular pathology. The authors reviewed the structure, physiology and pathology of the endothelial glycocalyx, based on a literature search of the past five years. In the second part, we have systematically reviewed interventions to protect or repair the glycocalyx. Glycocalyx damage can be caused by hypervolemia and hyperglycemia and can be prevented by maintaining a physiological concentration of plasma protein, particularly albumin. Other interventions have been investigated in animal models: these require clinical research before their introduction into medical practice.
The Endothelial Glycocalyx: Composition, Functions, and Visualization.
Reitsma S, Slaaf DW, Vink H, van Zandvoort MA. oude Egbrink MG
Pflugers Archiv: Eur J Physiol. 2007;454:345–59.
This review aims at presenting state-of-the-art knowledge on the composition and functions of the endothelial glycocalyx. The endothelial glycocalyx is a network of membrane-bound proteoglycans and glycoproteins, covering the endothelium luminally. Both endothelium- and plasma-derived soluble molecules integrate into this mesh. Over the past decade, insight has been gained into the role of the glycocalyx in vascular physiology and pathology, including mechanotransduction, hemostasis, signaling, and blood cell-vessel wall interactions. The contribution of the glycocalyx to diabetes, ischemia/reperfusion, and atherosclerosis is also reviewed. Experimental data from the micro- and macrocirculation alludes at a vasculoprotective role for the glycocalyx. Assessing this possible role of the endothelial glycocalyx requires reliable visualization of this delicate layer, which is a great challenge. An overview is given of the various ways in which the endothelial glycocalyx has been visualized up to now, including first data from two-photon microscopic imaging.
In summary, the endothelial glycocalyx appears to be perturbed in several vascular diseases. It remains to be elucidated whether glycocalyx perturbation is causally involved in the pathophysiology of these diseases. If so, restoration of the glycocalyx may be a therapeutic target of interest. Furthermore, identification of specific glycosaminoglycan domains involved in these diseases, as a platform for other substances or signaling pathways, might also prove to be of therapeutic value
Therapeutic Strategies Targeting the Glycocalyx: Acute Deficits,but Great Potential.
Becker BF, Chappell D, Bruegger D, Annecke T, Jacob M.
Cardiovasc Res. 2010;87:300–10.
Damage of the endothelial glycocalyx, which ranges from 200 to 2000 nm in thickness, decreases vascular barrier function and leads to protein extravasation and tissue edema, loss of nutritional blood flow, and an increase in platelet and leucocyte adhesion. Thus, its protection or the restoration of an already damaged glycocalyx seems to be a promising therapeutic target both in an acute critical care setting and in the treatment of chronic vascular disease. Drugs that can specifically increase the synthesis of glycocalyx components, refurbish it, or selectively prevent its enzymatic degradation do not seem to be available. Pharmacological blockers of radical production may be useful to diminish the oxygen radical stress on the glycocalyx. Tenable options are the application of hydrocortisone (inhibiting mast-cell degranulation), use of antithrombin III (lowering susceptibility to enzymatic attack), direct inhibition of the cytokine tumor necrosis factor-alpha, and avoidance of the liberation of natriuretic peptides (as in volume loading and heart surgery). Infusion of human plasma albumin (to maintain mechanical and chemical stability of the endothelial surface layer) seems the easiest treatment to implement.
Benefits derived from numerous clinically established therapeutic agents, especially hydrocortisone and antithrombin, may be, at least partly, based on the protection of the endothelial glycocalyx from enzymatic destruction. Inflammatory mediators released due to trauma and critical illness, foremost TNF-alpha, as well as ANP, liberated in the course of volume expansion or heart surgery, are to be regarded as sure candidates initiating such destruction. TNF-alpha may be directly inhibited using pharmacologically available antagonists. Stabilization of resident tissue mast cells offers a convincing alternative, since mast cells are a prodigious source of TNF-alpha and many other cytokines and chemokines, as well as of numerous proteases and heparinase in man. Effects of ANP and other natriuretic peptides on the glycocalyx, elicited perhaps via the activation of metalloproteases, are best precluded by the avoidance or minimization of mechanical stress to the heart. Iatrogenic hypervolemia has a negative impact on the integrity of the endothelial glycocalyx. In addition, its mechanical destruction, especially if protein-denuded, appears conceivable. Antithrombin seems to proffer protection from enzymatic attack, but here, as in all other proposed therapeutic options, there is no direct clinical proof for such a mode of action. Selective inhibition of a given protease or group of proteases in order to prevent shedding of the glycocalyx is not regarded as a viable option by us, since too many enzymes seem capable of attack (unpublished personal work). In the near future, we may expect a choice of anesthetic regimens as prophylactic aid in attenuating damage to the glycocalyx, augmenting the increasingly well-established avoidance of volume-loading procedures in clinical care. One of the simplest options to implement at this time is to maintain physiological levels of albumin in plasma and in solutions bathing isolated tissues.
Curr. Opin. Lipidol., (5):507-511
Although cardiovascular prevention has improved substantially, we still face the challenge of finding new targets to reduce the sequelae of atherosclerosis further. In this regard, optimizing the vasculoprotective effects of the vessel wall itself warrants intensive research. In particular, the endothelial glycocalyx, consisting of proteoglycans, glycoproteins and adsorbed plasma proteins, may play an essential role in protecting the vessel wall from atherosclerosis. In this review, we will discuss the different vasculoprotective effects exerted by the endothelial glycocalyx, the factors that damage it, and the first preliminary data on the glycocalyx dimension in humans. Whereas most glycocalyx research has traditionally focused on the microvasculature, more recent data have underscored the importance of the glycocalyx in protecting the macrovasculature against pro-atherogenic insults. It has been shown that glycocalyx loss is accompanied by a wide array of unfavorable changes in both small and larger vessels. Pro-atherogenic stimuli increase the shedding of glycocalyx constituents into the circulation, contributing to the progressive loss of the vasculoprotective properties of the vessel wall. Novel techniques have facilitated reproducible measurements of systemic glycocalyx volume in humans. Consistent with experimental data, the volume of the human glycocalyx is also severely perturbed by exposure to atherogenic risk factors. Cumulating evidence suggests that an intact glycocalyx protects the vessel wall, whereas disruption of the glycocalyx upon atherogenic stimuli increases vascular vulnerability for atherogenesis.
Syndecans in inflammation.
FASEB J. 2003;17:575–91.
Cell surface heparan sulfate (HS) influences a multitude of molecules, cell types, and processes relevant to inflammation. HS binds to cell surface and matrix proteins, cytokines, and chemokines. These interactions modulate inflammatory cell maturation and activation, leukocyte rolling, and tight adhesion to endothelium, as well as extravasation and chemotaxis. The syndecan family of transmembrane proteoglycans is the major source of cell surface HS on all cell types. Recent in vitro and in vivo data suggest the involvement of syndecans in the modulation of leukocyte–endothelial interactions and extravasation, the formation of chemokine and kininogen gradients, participation in chemokine and growth factor signaling, as well as repair processes. Thus, the complex role of HS in inflammation is reflected by multiple functions of its physiological carriers, the syndecans. Individual and common functions of the four mammalian syndecan family members can be distinguished. Recently generated transgenic and knockout mouse models will facilitate analysis of the individual processes that each syndecan is involved in.
Heparin and heparan sulfate influence multiple molecules, cell types, and processes in inflammation. In the past, the multitude of HS-mediated events has often been confusing and hard to analyze. However, an analysis of the proteoglycans which are the physiological carriers of HS chains in multicellular organisms, allows for a more detailed analysis of HS function in inflammation. The syndecans are the major source of cell surface heparan sulfate on all cell types relevant to the inflammatory process. Shedding of their intact ectodomains converts these versatile molecules to soluble effectors which can compete for ligands with their cell-surface counterparts and which can escape the spatial restrictions of membrane-bound molecules. Spatially and temporally regulated expression of syndecan core proteins allows for a control of cell surface HS expression and thus for a regulation of HS-dependent steps during inflammatory events. The differential expression of syndecans in response to inflammatory stimuli is a first sign of their direct involvement in these processes. A plethora of in vitro data on the role of syndecans as coreceptors, signaling receptors and binding partners for chemokines, cytokines, growth factors, integrins and other adhesion molecules, supports their role as integral parts of inflammatory events. It appears that many, if not most, of the HS-mediated effects on inflammation can be replicated by the individual or combined forces of one or several syndecans. Syndecans could therefore serve as new targets for the prevention of pathologic inflammatory events. Recent data on syndecan knockout mouse models provide further evidence for the physiological relevance of syndecan function in vivo. Interference with several steps of HS synthesis results in severe phenotypes in knockout mice. However, syndecan-deletions have a more subtle effect which facilitates analysis of their function. Both syndecan-1 and syndecan-4 −/− mice display inflammation-related phenotypes. A detailed analysis of the mechanistic principles underlying these still complex phenotypes will help to clarify the exact role(s) of the individual members of the syndecan family in the near future.
Growth Differentiation Factor 15 as a Biomarker in Cardiovascular Disease.
Kai C Wollert, Tibor Kempf, Lars Wallentin
Growth Differentiation Factor 15 as a Biomarker in Cardiovascular Disease, Clinical Chemistry, Volume 63, Issue 1, 1 January 2017, Pages 140–151,
Growth differentiation factor 15 (GDF-15) is expressed and secreted in response to inflammation, oxidative stress, hypoxia, telomere erosion, and oncogene activation. Cardiovascular (CV) disease is a major driver of GDF-15 production. GDF-15 has favorable preanalytic characteristics and can be measured in serum and plasma by immunoassay. In community-dwelling individuals’ higher concentrations of GDF-15 are associated with increased risks of developing CV disease, chronic kidney disease, and cancer, independent of traditional CV risk factors, renal function, and other biomarkers (C-reactive protein, B-type natriuretic peptide, cardiac troponin). Low concentrations of GDF-15 are closely associated with longevity. GDF-15 is as an independent marker of all-cause mortality and CV events in patients with coronary artery disease and may help select patients with non–ST-elevation acute coronary syndrome for early revascularization and more intensive medical therapies. GDF-15 is independently associated with mortality and nonfatal events in atrial fibrillation and heart failure (HF) with preserved or reduced ejection fraction. GDF-15 reflects chronic disease burden and acute perturbations in HF and responds to improvements in hemodynamic status. GDF-15 is independently associated with major bleeding in patients receiving antithrombotic therapies and has been included in a new bleeding risk score, which may become useful for decision support.
Role of syndecans in lipid metabolism and human diseases
by Leonova, Elena I; Galzitskaya, Oxana V
Advances in experimental medicine and biology, 2015, Volume 855
Syndecans are transmembrane heparan sulfate proteoglycans involved in the regulation of cell growth, differentiation, adhesion, neuronal development, and lipid metabolism. Syndecans are expressed in a tissue-specific manner to facilitate diverse cellular processes. As receptors and co-receptors, syndecans provide promising therapeutic targets that bind to a variety of physiologically important ligands. Negatively charged glycosaminoglycan chains of syndecans, located in the extracellular compartment, are critical for such binding. Functions of syndecans are as diverse as their ligands. For example, hepatic syndecan-1 mediates clearance of triglyceride-rich lipoproteins. Syndecan-2 promotes localization of Alzheimer’s amyloid Aβ peptide to the cell surface, which is proposed to contribute to amyloid plaque formation. Syndecan-3 helps co-localize the appetite-regulating melanocortin-4 receptor with its agonist, leading to an increased appetite. Finally, syndecan-4 initiates the capture of modified low-density lipoproteins by macrophages and thereby promotes the atheroma formation. We hypothesize that syndecan modifications such as desulfation of glycosaminoglycan chains may contribute to a wide range of diseases, from atherosclerosis to type 2 diabetes. At the same time, desulfated syndecans may have beneficial effects, as they can inhibit amyloid plaque formation or decrease the appetite. Despite considerable progress in understanding diverse functions of syndecans, the complex physiological roles of this intriguing family of proteoglycans are far from clear. Additional studies of syndecans may potentially help develop novel therapeutic approaches and diagnostic tools to alleviate complex human diseases such as cardiovascular and Alzheimer’s diseases.
Update on the important new drug target in cardiovascular medicine - the vascular glycocalyx
by Drake-Holland, A J; Noble, M I M
Cardiovascular & hematological disorders drug targets, 09/2012, Volume 12, Issue 1
We reviewed this subject in 2009, pointing out that, to the process of atherothrombosis, glycocalyx dysfunction and damage must be added to the previous known causative factors. Glycocalyx dysfunction is possibly the very first step in the process of atherothrombosis, being a protective layer between the endothelial cells and the blood. We emphasize the unique feature of glycocalyx mediated vasodilatation in that it is initiated purely by mechanical changes, i.e., changes in vascular wall shear stress, allowing conduit arteries to adjust diameter to demanded blood flow rate. The predilection of atheroma to sites of low shear stress, the inhibition of the shear response by luminal hyperglycemia, and the fact that the response is mediated by nitric oxide (NO), an anti-atheromatous agent has led to the hypothesis that impairment of this pathway is pro-atherogenic. In the microcirculation it has been shown that the glycocalyx must be added to the factors involved in the Starling hypothesis of tissue fluid generation and exchange. As a consequence, glycocalyx dysfunction in hyperglycemia has been postulated to cause edema and microalbinuria. We suggested that perhaps the arterial glycocalyx will become the most important for future early prevention of people at risk of cardiovascular disease. The advances in this subject since 2009 are the subject of the present review. What has struck us when searching the literature is that research into the glycocalyx has increased very much and now comes from many disciplines; e.g., diabetes, hypertension, bioengineering, physiology, critical care, cardiology, shock. This update is by no means exhaustive, but hopes, again, to bring to the attention of the pharmaceutical industry, the need for grants in the appropriate experimental models.
Update on the Important New Drug Target in Cardiovascular Medicine – the Vascular Glycocalyx Cardiovascular & Hematological Disorders-Drug Targets 2009
by A. J. Drake-Holland; M. I.M. Noble
Glycocalyx dysfunction is possibly the very first step in the process of atherothrombosis, as it is the protective layer between the endothelial cells and the blood. They emphasize the unique feature of glycocalyx mediated vasodilatation as it is initiated purely by mechanical changes (i.e. changes in vascular wall shear stress, allowing conduit arteries to adjust diameter to demanded blood flow rate). The predilection of atheroma to sites of low shear stress, the inhibition of the shear response by luminal hyperglycemia, and the fact that the response is mediated by nitric oxide (NO), an anti-atheromatous agent has led to the hypothesis that impairment of this pathway is pro-atherogenic. In the microcirculation, it has been shown that the glycocalyx must be added to the factors involved in the Starling hypothesis of tissue fluid generation and exchange. As a consequence, glycoalyx dysfunction in hyperglycemia has been hypothesized to cause edema and microalbinuria. The authors suggest that perhaps the arterial glycocalyx will become the most important for future early prevention of people at risk of cardiovascular disease. The advances in this subject since 2009 are the subject of the present review. They found that when searching the literature is that research into the glycocalyx has increased very much and now comes from many disciplines; e.g., diabetes, hypertension, bioengineering, physiology, critical care, cardiology, shock. This update is by no means exhaustive, but hopes, again, to bring to the attention of the pharmaceutical industry, the need for grants in the appropriate experimental models. In 2009, they asserted that other risk factors such as smoking, hypertension, hyperinsulinemia, hyperhomocysteinaemia and surgical operations should also be studied from the point of view of effects on the vascular glycocalyx. This recommendation appears not to have been taken up to any extent to date. Therefore, we think that this is still a requirement for future research. It is disappointing that grant giving bodies and the pharmaceutical industry continue to provide inadequate support for studies on the glycocalyx of the conduit arteries. It is conduit arteries that are the site of the principle debilitating and killing cardiovascular disease – atherosclerosis.
The endothelial glycocalyx: composition, functions, and visualization
Pflugers Arch - Eur J Physiol (2007) 454:345–359 By: Sietze Reitsma & Dick W. Slaaf & Hans Vink & Marc A. M. J. van Zandvoort & Mirjam G. A. oude Egbrink DOI 10.1007/s00424-007-0212-8
This article aims at presenting state-of-the-art knowledge on the composition and functions of the endothelial glycocalyx. The endothelial glycocalyx is a network of membrane-bound proteoglycans and glycoproteins, covering the endothelium luminally. Both endothelium and plasma derived soluble molecules integrate into this mesh. Over the past decade, insight has been gained into the role of the glycocalyx in vascular physiology and pathology, including mechanotransduction, hemostasis, signaling, and blood cell–vessel wall interactions. The contribution of the glycocalyx to diabetes, ischemia/reperfusion, and atherosclerosis is also reviewed. Experimental data from the micro- and macrocirculation alludes at a vasculoprotective role for the glycocalyx. Assessing this possible role of the endothelial glycocalyx requires reliable visualization of this delicate layer, which is a great challenge. An overview is given of the various ways in which the endothelial glycocalyx has been visualized up to now, including first data from two-photon microscopic imaging.
Overlying the vascular endothelium, the glycocalyx is a membrane-bound mesh in which plasma-derived molecules integrate. It exerts a variety of functions, important in normal vascular physiology and also in vascular disease. Although data from experiments in microcirculation, and more recently, in macrocirculation strongly suggests a vasculoprotective role for the glycocalyx, research on this subject is hampered by lack of a good visualization technique. Two photon laser scanning microscopy may prove to be a successful tool in achieving direct visualization of the glycocalyx in larger arteries in rodents, both ex vivo and in vivo, with the possibility to analyze focal variations in the composition or integrity of this layer.
Imaging the Endothelial Glycocalyx In Vitro by Rapid Freezing/Freeze Substitution Transmission Electron Microscopy
by Ebong, Eno E; Macaluso, Frank P; Spray, David C; Tarbell, John M Arterioscler Thromb Vasc Biol 08/2011
Recent publications questioned the validity of endothelial cell (EC) culture studies of glycocalyx (GCX) function because of findings that GCX in vitro may be substantially thinner than GCX in vivo. The assessment of thickness differences is complicated by GCX collapse during dehydration for traditional electron microscopy. The authors measured in vitro GCX thickness using rapid freezing/freeze substitution (RF/FS) transmission electron microscopy (TEM), taking advantage of the high spatial resolution provided by TEM and the capability to stably preserve the GCX in its hydrated configuration by RF/FS. Bovine aortic EC (BAEC) and rat fat pad EC were subjected to conventional or RF/FS-TEM. Conventionally preserved BAEC GCX was ≈0.040 μm in thickness. RF/FS-TEM revealed impressively thick BAEC GCX of ≈11 μm and rat fat pad EC GCX of ≈5 μm. RF/FS-TEM also discerned GCX structure and thickness variations due to heparinase III enzyme treatment and extracellular protein removal, respectively. Immunoconfocal studies confirmed that the in vitro GCX is several micrometers thick and is composed of extensive and well-integrated heparan sulfate, hyaluronic acid, and protein layers. New observations by RF/FS-TEM reveal substantial GCX layers on cultured EC, supporting their continued use for fundamental studies of GCX and its function in the vasculature.
Plasminogen activator inhibitor‐1, inflammation, obesity, insulin resistance and vascular risk
by Juhan‐Vague, I; Alessi, M‐C; Mavri, A; Morange, P. E
Journal of Thrombosis and Hemostasis, 07/2003, Volume 1, Issue 7
Elevated plasma plasminogen activator inhibitor‐1 (PAI‐1) level is a core feature of insulin‐resistance syndrome (IRS). Atherothrombotic complications in IRS are partly attributed to impaired fibrinolysis caused by increased plasma PAI‐1 levels. Although the etiology of IRS is far from being explained, the clustering of inflammation, adipose tissue accumulation and insulin resistance suggests an etiopathological link. Proinflammatory cytokines might regulate PAI‐1 expression in IRS; however, more studies are needed to confirm this complex mechanism in humans. Furthermore, modifying PAI‐1 expression by PAI‐1 inhibitors provides a new challenge and may reveal the true role of PAI‐1 in atherosclerotic and insulin resistance processes.
PAI‐1 could represent a potential target for therapeutic intervention that aims to decrease the risk of both cardiovascular disease and Type 2 diabetes. Studies with use of PAI‐1 inhibitors in animal models of obesity and insulin resistance are needed to delineate the true contribution of PAI‐1 to both cardiovascular and metabolic complications of insulin resistance.
Degradation of the Endothelial Glycocalyx in Clinical Settings: Searching for the Sheddases
by Becker, Bernhard F; Jacob, Matthias; Leipert, Stephanie; Salmon, Andrew H. J; Chappell, Daniel
British Journal of Clinical Pharmacology p389 - 402 09/2015
The endothelial glycocalyx has a profound influence at the vascular wall on the transmission of shear stress, on the maintenance of a selective permeability barrier and a low hydraulic conductivity, and on attenuating firm adhesion of blood leukocytes and platelets. Major constituents of the glycocalyx, including syndecans, heparan sulphates and hyaluronan, are shed from the endothelial surface under various acute and chronic clinical conditions, the best characterized being ischemia and hypoxia, sepsis and inflammation, atherosclerosis, diabetes, renal disease and hemorrhagic viral infections. Damage has also been detected by in vivo microscopic techniques. Matrix metalloproteases may shed syndecans and heparinase, released from activated mast cells, cleaves heparan sulphates from core proteins. According to new data, not only hyaluronidase but also the serine proteases thrombin, elastase, proteinase 3 and plasminogen, as well as cathepsin B lead to loss of hyaluronan from the endothelial surface layer, suggesting a wide array of potentially destructive conditions. Appropriately, pharmacological agents such as inhibitors of inflammation, antithrombin and inhibitors of metalloproteases display potential to attenuate shedding of the glycocalyx in various experimental models. Also, plasma components, especially albumin, stabilize the glycocalyx and contribute to the endothelial surface layer. Though symptoms of the above listed diseases and conditions correlate with sequelae expected from disturbance of the endothelial glycocalyx (edema, inflammation, leukocyte and platelet adhesion, low reflow), therapeutic studies to prove a causal connection have yet to be designed. With respect to studies on humans, some clinical evidence exists for benefits from application of sulodexide, a preparation delivering precursors of the glycocalyx constituent heparan sulphate. At present, the simplest option for protecting the glycocalyx seems to be to ensure an adequate level of albumin. However, also in this case, definite proof of causality needs to be delivered. Deterioration of the endothelial glycocalyx/endothelial surface layer is currently being associated with a growing number of pathological states. Clinical studies confirming that protection of the endothelial glycocalyx from degradation benefits clinical outcomes in these scenarios are sorely lacking. This is partly due to the fact that therapeutic strategies retain a large speculative element, completing a negative cycle. At present, therefore, innovative strategies in this emerging field of experimental medicine are desperately needed. The authors are convinced that the hunt for such solutions is very much worth the effort.
Role for Glycocalyx Perturbation in Atherosclerosis Development and Associated Microvascular Dysfunction
by Brands, Judith; Van Teeffelen, Jurgen WGE; Van den Berg, Bernard M; Vink, Hans
Future Lipidology, 10/2007, Volume 2, Issue 5
The importance of the endothelial glycocalyx for vascular homeostasis is becoming more and more evident. This review addresses the potential relation between a damaged glycocalyx and the process of atherosclerosis, including the associated impairment in blood-flow regulation. Brands, et. Al. envision restoration of glycocalyx perturbation in the future as a potential therapy for early treatment of cardiovascular disease. Cardiovascular disease is the leading cause of death and illness in developed countries, and atherosclerosis makes up the single most important contributor. When focusing on the heart, the presence of a lesion can easily be overlooked if dilation of the vasculature distal from the lesion, specifically the microcirculation, is able to compensate for the increase in resistance and coronary blood flow can be maintained. However, when compensation by the microcirculation fails, coronary perfusion will become inadequate and consequently myocardial infarction might occur. The endothelial glycocalyx has been indicated to play a role in protection of the vascular wall against atherosclerotic insults, as well as regulation of microvascular function. Both aspects are discussed in this review.
Glycocalyx as protective barrier between endothelium & blood
* Glycocalyx is located at the luminal side of the vasculature, is composed of polysaccharides and plasma proteins, has a thickness of approximately half a micron and significantly excludes circulating plasma and red blood cells.
* Enzymatic degradation of the glycocalyx has been associated with increased vessel wall adhesiveness and vascular leakage, coagulation activation and impaired shear-dependent nitric oxide production.
Glycocalyx might constitute a first line of defense against atherosclerosis
* Endothelial glycocalyx is thinner at sites prone for atherosclerosis.
* Hyperglycemic, inflammatory and atherogenic conditions result in glycocalyx perturbation.
Glycocalyx is important for microvascular regulation
* Glycocalyx plays a pivotal role in shear stress-dependent nitric oxide-mediated dilation of resistance vessels. Both polysaccharides and adsorbed plasma proteins are important for the mechanotransduction properties.
* Glycocalyx reduces functionally-perfused capillary volume by 20-40% under control conditions. Whereas physiological 'recruitment' of glycocalyx volume by agonists might increase capillary volume for perfusion and exchange, glycocalyx degradation is ultimately associated with capillary perfusion impairments.
* Assessment of the condition of the glycocalyx might be used as prognostic tool for early determination of vascular damage.
* Glycocalyx restoration might be used as therapy to increase the atheroprotective properties of the vascular wall.
Plasminogen activator inhibitor-1 (PAI-1): a key factor linking fibrinolysis and age-related subclinical and clinical conditions
by Cesari, Matteo; Pahor, Marco; Incalzi, Raffaele Antonelli, Cardiovascular therapeutics, 10/2010, Volume 28, Issue 5
The close relationship existing between aging and thrombosis has increasingly been studied in the last decade. The age-related development of a prothrombotic imbalance in the fibrinolysis homeostasis has been hypothesized as the basis of this increased cardiovascular and cerebrovascular risk. Fibrinolysis is the result of the interactions among multiple plasminogen activators and inhibitors constituting the enzymatic cascade, and ultimately leading to the degradation of fibrin. The plasminogen activator system plays a key role in a wide range of physiological and pathological processes. Plasminogen activator inhibitor-1 (PAI-1) is a member of the superfamily of serine-protease inhibitors, and the principal inhibitor of both the tissue-type and the urokinase-type plasminogen activator, the two plasminogen activators able to activate plasminogen. Current evidence describing the central role played by PAI-1 in a number of age-related subclinical (i.e., inflammation, atherosclerosis, insulin resistance) and clinical (i.e., obesity, comorbidities, Werner syndrome) conditions is presented. Despite some controversial and unclear issues, PAI-1 represents an extremely promising marker that may become a biological parameter to be progressively considered in the prognostic evaluation, in the disease monitoring, and as treatment target of age-related conditions in the future. There is still a lot to understand in the complex network of interactions existing between the fibrinolytic system, inflammation, oxidative (and antioxidant) status, adipose tissue (and skeletal muscle), metabolic syndrome, and atherosclerotic diseases. Current evidence, despite some contradictions and controversies, tend to indicate PAI-1 as an extremely promising marker potentially linking several of these pathways, organs, and conditions. This adipokine may become a biological parameter to be considered in the prognostic evaluation, in the disease monitoring, and as treatment target.
Serum Hyaluronan as a Disease Marker
by Laurent, Torvard C; Laurent, Ulla B. G; Fraser, J.Robert E
Annals of Medicine, 1996, Volume 28, Issue 3
Hyaluronan is a connective tissue polysaccharide which has also been found in blood serum in concentrations < 100 micrograms/L (average 30-40 micrograms/L in middle-aged persons). The serum level is regulated by the influx of the polysaccharide from the tissues via lymph and its receptor-mediated clearance by liver endothelial cells. Markedly high serum levels are noted in certain liver diseases, especially in patients with cirrhosis, when the clearance is impaired. In these cases, serum hyaluronan can be used to follow the development of the disease. Serum hyaluronan is also a sensitive marker for impending rejection of liver transplants. Patients with rheumatoid arthritis constitute another major group with increased serum hyaluronan, but in this case the level varies markedly during the day corresponding to physical activity. There are good indications that in these subjects the excess hyaluronan comes from the joints. Under stringent sampling conditions of serum, it should be possible to extract interesting information on the inflammatory joint process. Increased hyaluronan levels are also seen in other inflammatory diseases and it is of special interest that high hyaluronan levels in patients with septic conditions is a sign of poor prognosis. Certain tumors, notably Wilms' tumor and mesothelioma, produce factors which activate synthesis of hyaluronan and increase its serum level. Rare hereditary diseases with disturbances of hyaluronan metabolism and elevated blood levels have also been discovered, e.g. Werner's syndrome and cutaneous hyaluronanosis. Information accumulated during the last decade regarding the metabolism of hyaluronan has made this polysaccharide an interesting clinical marker for several pathological conditions.
Lack of association of plasma gamma prime (γ') fibrinogen with incident cardiovascular disease.
Appiah D, Heckbert SR, Cushman M, Psaty BM, Folsom AR.
Thrombosis Research. 2016 Jul;143:50-52. DOI: 10.1016/j.thromres.2016.04.023.
The association of gamma prime (γ') fibrinogen; a fibrinogen γ chain variant generated via alternative mRNA processing, with cardiovascular disease (CVD) remains equivocal. We prospectively examine the association of plasma γ' fibrinogen with the incidence of multiple cardiovascular disease (CVD) endpoints, independent of established CVD risk factors and total fibrinogen. We measured plasma γ' fibrinogen on plasma samples collected in 1992-1993 from adults ≥65years (n=3219) enrolled in the Cardiovascular Health Study, who were followed through 2013 for incident CVD events. In multivariable Cox models adjusted for traditional CVD risk factors and total fibrinogen, the hazard ratio per 1 standard deviation (10.7mg/dl) increment of γ' fibrinogen was 1.02 (95%CI: 0.95-1.10) for coronary heart disease; 0.88 (0.77-1.00) for ischemic stroke; 1.07 (0.87-1.32) for peripheral artery disease; 1.00 (0.92-1.08) for heart failure and 1.01 (0.92-1.10) for CVD mortality. Likewise, we failed to show a statistically significant association of γ'/total fibrinogen ratio with any CVD endpoint. These results suggest that among the elderly, γ' fibrinogen does not add much to CVD prediction beyond traditional risk factors and total fibrinogen level.
Diagnostic Accuracy and Clinical Utility of Noninvasive Testing for Coronary Artery Disease
by Weustink, Annick C; Mollet, Nico R; Neefjes, Lisan A; Meijboom, W; Galema, Tjebbe; Van Mieghem, Carlos; Kyrzopoulous, Stamatis; Neoh Eu, Rick; Nieman, Koen; Cademartiri, Filippo; Van Geuns, Robert-Jan; Boersma, Eric; P. Krestin Gabriel; De Feyter, Pim J. Annals of internal medicine, 05/2010, Volume 152, Issue 10
Computed tomography coronary angiography (CTCA) has become a popular noninvasive test for diagnosing coronary artery disease. The authors sought to compare the accuracy and clinical utility of stress testing and CTCA for identifying patients who require invasive coronary angiography (ICA). Computed tomography coronary angiography seems most valuable in patients with intermediate pretest probability of disease, because the test can distinguish which of these patients need invasive angiography. These findings need to be confirmed before CTCA can be routinely recommended for these patients.
Pregnancy-associated plasma protein A as a marker of acute coronary syndromes
Antoni Bayes-Genis, M.D., Cheryl A. Conover, Ph.D., Michael T. Overgaard, Ph.D., Kent R. Bailey, Ph.D., Michael Christiansen, M.D., David R. Holmes, Jr., M.D., Renu Virmani, M.D., Claus Oxvig, Ph.D., and Robert S. Schwartz, M.D.
October 4, 2001
N Engl J Med 2001; 345:1022-1029
Circulating markers indicating the instability of atherosclerotic plaques could have diagnostic value in unstable angina or acute myocardial infarction. We evaluated pregnancy-associated plasma protein A (PAPP-A), a potentially proatherosclerotic metalloproteinase, as a marker of acute coronary syndromes.
We examined the level of expression of PAPP-A in eight culprit unstable coronary plaques and four stable plaques from eight patients who had died suddenly of cardiac causes. We also measured circulating levels of PAPP-A, C-reactive protein, and insulin-like growth factor I (IGF-I) in 17 patients with acute myocardial infarction, 20 with unstable angina, 19 with stable angina, and 13 controls without atherosclerosis.
PAPP-A is present in unstable plaques, and circulating levels are elevated in acute coronary syndromes; these increased levels may reflect the instability of atherosclerotic plaques. PAPP-A is a new candidate marker of unstable angina and acute myocardial infarction.
Pregnancy-associated plasma protein-A (PAPP-A) and cardiovascular risk
Sancheza LC, Frederick S, Kaski JC
The search for markers to improve risk prediction for individuals at risk of developing serious cardiovascular events is ongoing. New markers of coronary artery disease progression have been identified in recent years, among which, circulating levels of pregnancy-associated plasma protein-A (PAPP-A) offer an interesting profile. PAPP-A may play a role in the development of atherosclerotic lesions and represent also a marker of atheromatous plaque instability and extent of cardiovascular disease. PAPP-A has been shown to be a marker of adverse outcome in both acute coronary syndrome and stable coronary disease patients. The present article reviews currently available evidence supporting a role for PAPP-A as a marker of cardiovascular risk and discusses some of the pitfalls that may limit its use in clinical practice.
Pregnancy-associated plasma protein-A levels in patients with acute coronary syndromes: Comparison with markers of systemic inflammation, platelet activation, and myocardial necrosis.
Heeschen C., Dimmeler S., Hamm C., Fichtlscherer S., Simoons M., Zeiher A.
j.jacc.2004.09.060 vol. 45 no. 2 229-237
The goal of this study was to determine the predictive value of pregnancy-associated plasma protein-A (PAPP-A) in patients with acute coronary syndromes (ACS).
Pregnancy-associated plasma protein-A is a zinc-binding matrix metalloproteinase abundantly expressed in eroded and ruptured plaques and may serve as a marker of plaque destabilization.
In 547 patients with angiographically validated ACS and in a heterogeneous emergency room population of 644 patients with acute chest pain, respectively, PAPP-A as well as markers of myocardial necrosis (troponin T [TnT]), ischemia (vascular endothelial growth factor [VEGF]),
inflammation (high-sensitivity C-reactive protein [hsCRP]), anti-inflammatory activity (interleukin [IL]-10), and platelet activation (soluble CD40 ligand [sCD40L]) were determined. Patients were followed for the occurrence of death or myocardial infarction. The PAPP-A level as a marker of plaque instability is a strong independent predictor of cardiovascular events in patients with ACS. Simultaneous determination of biomarkers with distinct pathophysiological profiles appears to remarkably improve risk stratification in patients with ACS.
Inflammation in atherosclerosis
Nature 2002; 420: 868-874.
Abundant data link hypercholesterolemia to atherogenesis. However, only recently have we appreciated that inflammatory mechanisms couple dyslipidemia to atheroma formation. Leukocyte recruitment and expression of pro-inflammatory cytokines characterize early atherogenesis, and malfunction of inflammatory mediators mutes atheroma formation in mice. Moreover, inflammatory pathways promote thrombosis, a late and dreaded complication of atherosclerosis responsible for myocardial infarctions and most strokes. The new appreciation of the role of inflammation in atherosclerosis provides a mechanistic framework for understanding the clinical benefits of lipid-lowering therapies. Identifying the triggers for inflammation and unravelling the details of inflammatory pathways may eventually furnish new therapeutic targets.
PAI-1 4G/5G polymorphism and coronary artery disease risk: a meta-analysis
Zhongshu Liang, Weihong Jiang, Mao Ouyang, and Kan Yang
Int J Clin Exp Med. 2015; 8(2): 2097–2107.
Many epidemiologic studies have investigated the plasminogen activator inhibitor-1 (PAI-1) gene 4G/5G polymorphism and this association with coronary artery disease (CAD). But definite conclusions cannot be drawn. Related studies were identified from PubMed, Springer Link, Ovid, Chinese Wanfang Data Knowledge Service Platform, Chinese National Knowledge Infrastructure (CNKI), and Chinese Biology Medicine (CBM) till 10 August 2014. Pooled ORs and 95% CIs were used to assess the strength of the associations. A total of 53 studies including 20921 CAD cases and 18434 controls were included. Significantly elevated CAD risk was found in overall analysis (OR = 1.13, 95% CI: 1.05-1.21, P = 0.0009). In the subgroup analysis by races, significantly increased risk was found in Caucasians (OR = 1.11, 95% CI: 1.03-1.20, P = 0.005) and Asians (OR = 1.20, 95% CI: 1.01-1.42, P = 0.04). In the subgroup analysis by gender, significant association was found in males (OR = 1.15, 95% CI: 1.06-1.25, P = 0.0008), but was not found in females (OR = 1.05, 95% CI: 0.92-1.20, P = 0.47). In the subgroup analysis by age, young populations showed increased CAD risk (OR = 1.19, 95% CI: 1.02-1.37, P = 0.02), but old populations did not show this association (OR = 1.01, 95% CI: 0.82-1.24, P = 0.93). This meta-analysis provides the evidence that PAI-1 4G/5G polymorphism may contribute to the CAD development.
PAPP-A: A possible pathogenic link to the instability of atherosclerotic plaque
Xuping Li, Qiming Liu, Tao Zhou, Shuiping Zhao, Shenghua Zhou
Volume 70, Issue 3, 2008, Pages 597-599 10.1016/j.mehy.2007.05.043
The rupture of coronary atherosclerotic plaque and subsequent thrombus formation are major events underlying acute coronary syndromes (ACS). Pregnancy associated plasma protein A (PAPP-A) is a member of the metzincin superfamily of metalloproteinases originally identified in the serum of pregnant women. Recent studies indicate that ACS is associated with elevated serum concentrations of PAPP-A. PAPP-A level is not only a marker of plaque instability favoring the progression to myocardial infarction, but is indicative of a poor prognosis even after the occurrence of an acute ischemic event caused by plaque instability.
Why PAPP-A expression in unstable plaques is high is a puzzling problem. We hypothesized that PAPP-A is a possible cause of the instability of atherosclerotic plaque which plays a role in ACS. Studies found that PAPP-A was abundantly expressed in both eroded and ruptured plaques but was only minimally expressed in stable plaques. Other studies have also demonstrated that patients with hyperechoic or isoechoic carotid plaques exhibit significantly higher PAPP-A levels than those with hypoechoic early carotid lesions. If the hypothesis is confirmed, administration of PAPP-A monoclonal antibodies may be used to eliminate the pathogen. It will be a new target point to treat ACS.
The syndecans, tuners of transmembrane signaling
Zimmerman, P. and David, G
Syndecans, a family of transmembrane proteoglycans, are putative integrators of extracellular signals. The interaction of syndecans with extracellular ligands via particular motifs in their heparan sulfate chains, their clustering, association with particular cytoskeletal structures, binding to cytoplasmic effectors, and intracellular phosphorylation represent as many means to bring this role to a successful conclusion. This review briefly addresses the characteristics of syndecans as heparan sulfate proteoglycans (HSPGs) and focus mainly on the properties, binding interactions, and potential signaling functions of the cytoplasmic domains of these molecules.
Functions of Cell Surface Heparan Sulfate Proteoglycans
Merton Bernfield,, Martin Götte,, Pyong Woo Park,, Ofer Reizes,, Marilyn L. Fitzgerald,, John Lincecum, and, and Masahiro Zako
Annual Review of Biochemistry 1999 68:1, 729-777
The heparan sulfate on the surface of all adherent cells modulates the actions of a large number of extracellular ligands. Members of both cell surface heparan sulfate proteoglycan families, the transmembrane syndecans and the glycosylphosphoinositide-linked glypicans, bind these ligands and enhance formation of their receptor-signaling complexes. These heparan sulfate proteoglycans also immobilize and regulate the turnover of ligands that act at the cell surface. The extracellular domains of these proteoglycans can be shed from the cell surface, generating soluble heparan sulfate proteoglycans that can inhibit interactions at the cell surface. Recent analyses of genetic defects in Drosophila melanogaster, mice, and humans confirm most of these activities in vivo and identify additional processes that involve cell surface heparan sulfate proteoglycans. This chapter focuses on the mechanisms underlying these activities and on the cellular functions that they regulate.
Association of Plasma γ' Fibrinogen With Incident Cardiovascular Disease: The Atherosclerosis Risk in Communities (ARIC) Study.
Appiah D, Schreiner PJ, MacLehose RF, Folsom AR
The Atherosclerosis Risk in Communities (ARIC) study measured γ' fibrinogen by enzyme-linked immunosorbent assay in stored plasma samples from 1993 to 1995 and related levels in 10 601 adults to incident CVD end points (coronary heart disease), ischemic stroke, peripheral artery disease, heart failure, and CVD mortality through 2012 (median follow-up, 18 years). In Cox models accounting for established CVD risk factors and total fibrinogen levels, γ' fibrinogen was associated positively with peripheral artery disease (hazard ratio [HR] per 1-SD [8.80 mg/dL] increment, 1.14), heart failure (HR, 1.06), and CVD deaths (HR, 1.12) but not with incident coronary heart disease (HR, 1.01) or ischemic stroke (HR, 0.98). Additional adjustment for C-reactive protein, however, eliminated the associations with peripheral artery disease and heart failure. These findings do not lend support to the hypothesis that γ' fibrinogen influences CVD events through its prothrombotic properties. Rather, γ' fibrinogen concentrations seem to reflect general inflammation that accompanies and may contribute to atherosclerotic CVD, instead of γ' fibrinogen being a causal risk factor.
Baseline and long-term fibrinogen levels and risk of sudden cardiac death: A new prospective study and meta-analysis.
Kunutsor SK, Kurl S, Zaccardi F, Laukkanen JA.
Inflammatory markers such as C-reactive protein (CRP) and interleukin-6 have been linked with an increased risk of sudden cardiac death (SCD), but the relationship between fibrinogen and SCD is uncertain. We aimed to assess the association between fibrinogen and SCD.
Plasma fibrinogen was measured at baseline in a prospective cohort of 1773 men aged 42-61 years free of heart failure or cardiac arrhythmias, that recorded 131 SCDs during 22 years follow-up. Correction for within-person fibrinogen variability was made using data from repeat measurements taken several years apart.
Fibrinogen was strongly correlated with CRP, weakly correlated with several cardiovascular risk markers, and was log-linearly associated with SCD risk. In analyses adjusted for conventional risk factors, the hazard ratio (HR) (95% CIs) for SCD per 1 standard deviation (SD) higher baseline loge fibrinogen was 1.32 (1.11-1.57). The results remained consistent on further adjustment for alcohol consumption, resting heart rate, and circulating lipids 1.30 (1.09-1.56). The corresponding HRs were 1.80 (1.25-2.58) and 1.74 (1.20-2.52) after correction for within-person variability. HRs remained unchanged on further adjustment for CRP and accounting for incident coronary events. In a meta-analysis of three cohort studies, the fully-adjusted relative risks for SCD per 1 SD higher baseline and long-term fibrinogen levels were 1.42 (1.25-1.61) and 2.07 (1.59-2.69) respectively. The associations were similar for non-SCDs in both cohort analysis and the meta-analysis. Addition of plasma fibrinogen to a SCD risk prediction model containing established risk factors did not significantly improve risk discrimination but improved the net reclassification. Available data suggest fibrinogen is positively, log-linearly, and independently associated with risk of SCD. Further research is needed to assess the potential relevance of plasma fibrinogen concentrations in SCD prevention.
Biomarkers for characterization of heart failure - Distinction of heart failure with preserved and reduced ejection fraction.
Sinning C, Kempf T, Schwarzl M, Lanfermann S, Ojeda F, Schnabel RB, Zengin E, Wild PS, Lackner KJ, Munzel T, Blankenberg S, Wollert KC, Zeller T, Westermann D.
Heart failure (HF) incidence is rising worldwide and HF with preserved ejection fraction (HFpEF) represents nearly half of all cases. Treatment options are still limited in HFpEF in comparison to HF with reduced ejection fraction (HFrEF).
We analyzed biomarkers in the general population to characterize HFpEF and HFrEF and defined a biomarker index to differentiate HFpEF from HFrEF. Growth differentiation factor-15 (GDF-15), soluble source of tumorigenicity 2 (sST2), C-reactive protein (CRP) and NT-proBNP were measured in 5000 individuals of the population-based Gutenberg Health Study (GHS). The median follow-up time for all-cause mortality was 7.3years with 213 events.
Identification of subjects with HF was improved by GDF-15 (p<0.001) in addition to NT-proBNP with an odds ratio (OR) of 1.4 (95% confidence interval [CI]:1.1-1.7). Discrimination of subjects with and without HF was slightly higher for GDF-15 (area under the ROC curve [AUC]:0.79 [95%CI:0.75-0.83]) compared to NT-proBNP (AUC:0.77 [95% CI:0.72-0.82]). For subjects with HF, differentiating HFpEF from HFrEF was feasible with the index ((CRP+GDF-15+sST2)/NT-proBNP) with an OR of 3.7 (95% CI:1.9-8.5) (p<0.001). The best biomarkers predicting all-cause mortality were NT-proBNP and GDF-15 with a hazard ratio (HR) of 1.9 (95% CI:1.6-2.2) and 1.7 (95%CI:1.6-1.9) (both p<0.001), respectively.
GDF-15 was useful to detect prevalent HF in addition to NT-proBNP and was elevated in HFrEF and HFpEF, whereas NT-proBNP was higher in HFrEF than in HFpEF. All biomarkers were useful to predict mortality in the general population. The index of ((CRP+GDF-15s+sST2)/NT-proBNP) was able to discriminate HFpEF from HFrEF.
Syndecan-1 in Acute Decompensated Heart Failure--Association with Renal Function and Mortality
by Neves, Fernanda Macedo de Oliveira; Meneses, Gdayllon Cavalcante; Sousa, Nazareth Ermínia Araujo; Menezes, Ramon Róseo Paula Pessoa Bezerra de; Parahyba, Marcelo Coelho; Martins, Alice Maria Costa; Libório, Alexandre Braga
Circulation journal: official journal of the Japanese Circulation Society, 2015, Volume 79, Issue 7
Heart failure (HF) is a leading cause of hospitalization throughout the world, and the mortality rate remains elevated. HF is frequently complicated by acute kidney injury (AKI), worsening the patient's prognosis. There have been no studies evaluating the role that endothelial glycocalyx damage plays in HF patients and its association with AKI and mortality. We measured several endothelial biomarkers in 201 consecutive patients with acute decompensated HF (ADHF) during emergency department (ED) admission. In-hospital mortality, AKI development and 6-month mortality rates were assessed. ADHF patients with worsening renal function had higher levels of syndecan-1 but not those patients with stable chronic kidney disease. Syndecan-1 levels during ED admission were predictive for AKI during the hospital stay (AUC 0.741, P<0.001) and had an even better discriminatory capacity in more severe AKI (AUC 0.812, P<0.001). Additionally, after adjusting for several confounding factors, including biomarkers of endothelial function and endothelial cell activation, syndecan-1 remained associated with in-hospital mortality rates. On a Cox multivariate analysis regression, syndecan-1 was associated with 6-month mortality rates. The concentration of syndecan-1, a marker of glycocalyx damage measured during ED admission, is valuable in assessing the risk of developing AKI and in-hospital mortality. Its association with mortality is strong after 6-month follow-up.
Measurement of syndecan-1, a marker of glycocalyx damage, on ED admission is a valuable tool for assessing the risk of developing AKI and in-hospital mortality. Its association with mortality is strong, even after a 6-month follow-up period.
The endothelial glycocalyx affords compatibility of Starling's principle and high cardiac interstitial albumin levels.
Jacob M, Bruegger D, Rehm M, Stoeckelhuber M, Welsch U, Conzen P, Becker BF.
Cardiovasc Res. 2007;73:575–86.
The objective of the study was to test the role of an oncotic pressure gradient across the endothelial glycocalyx with respect to extravasation of fluid and colloids and development of tissue edema in a whole organ setting. They measured filtration in the intact coronary system of isolated guinea pig hearts, comparing colloid-free perfusion and perfusion with 1.67% albumin or 2% hydroxyethylstarch (oncotic pressures 5.30 vs. 11.10 mm Hg, respectively). Heparinase was used to alter the endothelial glycocalyx. They found extremely high net organ hydraulic conductivity was obtained with colloid-free perfusion (9.14 microl/min/g tissue). Supplementing perfusate with albumin caused a significant decrease, also vs. hydroxyethylstarch (1.04 vs. 2.67 microl/min/g, p < 0.05). Albumin also lowered edema formation vs. the other perfusion modes (p < 0.05). Stripping the glycocalyx of heparan sulfate reduced the effect of colloids, especially that of albumin. The steady-state concentrations of hydroxyethylstarch and albumin in the mixed interstitial fluid leaving the intact coronary bed averaged about 95% of the intravascular level. Electron and light microscopy indicated that colloid extravasated mainly in the venular sections. The authors propose a low-filtration model for the coronary system with different barrier properties in arteriolar/capillary and venular sections. Arteriolar/capillary: very little fluid and colloid extravasation due to the endothelial surface layer formed by the glycocalyx and albumin plus the endothelial strand barrier; venular: little net extravasation of fluid and colloids despite large pores, because of low hydrostatic and oncotic pressure differences between intra- and extravascular spaces. The latter sites provide physiological access of large solutes (colloids) to the tissue.
Pregnancy associated plasma protein A, a potential marker for vulnerable plaque in patients with non-ST-segment elevation acute coronary syndrome
Iversena K, Teisner A, Teisner B, Kliem A, Thanning P, Nielsene H, Clemmensen P, Grande P
The purpose of the study was to describe the presence and time-related pattern of circulating pregnancy associated plasma protein A (PAPP-A) levels in patients with non-ST-segment elevation acute coronary syndrome (NSTE-ACS).
Consecutively admitted patients (N = 573) with clinical signs of NSTE-ACS were included. Blood samples for analysis of PAPP-A were drawn at admission and every 6–8 h until levels of biomarkers of myocardial necrosis showed a consistent decrease. PAPP-A seems to be a marker ischemia both in patients with low- and high-risk NSTE-ACS, possibly due to the release of PAPP-A from the vulnerable plaque.
Circulating Concentrations of Growth-Differentiation Factor 15 in Apparently Healthy Elderly Individuals and Patients with Chronic Heart Failure as Assessed by a New Immunoradiometric Sandwich Assay.
Tibor Kempf, Rüdiger Horn-Wichmann, Georg Brabant, Timo Peter, Tim Allhoff, Gunnar Klein, Helmut Drexler, Nina Johnston, Lars Wallentin, Kai C Wollert,
Circulating Concentrations of Growth-Differentiation Factor 15 in Apparently Healthy Elderly Individuals and Patients with Chronic Heart Failure as Assessed by a New Immunoradiometric Sandwich Assay, Clinical Chemistry, Volume 53, Issue 2, 1 February 2007, Pages 284–291,
Growth-differentiation factor 15 (GDF15) is a member of the transforming growth factor β (TGF-β) cytokine superfamily. There has been increasing interest in using circulating GDF15 as a biomarker in patients, for example those with cardiovascular disease. The IRMA can detect GDF15 in human serum and plasma with excellent sensitivity and specificity. The reference limits and confounding variables defined for apparently healthy elderly individuals and the favorable preanalytic characteristics of GDF15 are expected to facilitate future studies of GDF15 as a biomarker in various disease settings, including CHF.
Serial Measurement of Growth-Differentiation Factor-15 in Heart Failure Relation to Disease Severity and Prognosis in the Valsartan Heart Failure Trial.
Inder S. Anand, Tibor Kempf, Thomas S. Rector, Heike Tapken, Tim Allhoff, Franziska Jantzen, Michael Kuskowski, Jay N. Cohn, Helmut Drexler, and Kai C. Wollert
Growth-differentiation factor-15 (GDF-15) is emerging as a prognostic biomarker in patients with coronary artery disease. Little is known about GDF-15 as a biomarker in patients with heart failure.
The circulating concentration of GDF-15 was measured at baseline and at 12 months in patients randomized in the Valsartan Heart Failure Trial (Val-HeFT). GDF-15 reflects information from several pathological pathways and provides independent prognostic information in heart failure. GDF-15 levels increase over time, suggesting that GDF-15 reflects a pathophysiological axis that is not completely addressed by the therapies prescribed in Val-HeFT.
Soluble neprilysin, NT-proBNP, and growth differentiation factor-15 as biomarkers for heart failure in dialysis patients.
Claus R, Berliner D, Bavendiek U, Vodovar N, Lichtinghagen R, David S, Patecki M, Launay JM, Bauersachs J, Haller H, Hiss M, Balzer MS.
Clin Res Cardiol. 2020 Jan 30. doi: 10.1007/s00392-020-01597-x
Dialysis patients are at increased risk of HF. However, diagnostic utility of NT-proBNP as a biomarker is decreased in patients on dialysis. GDF-15 and cNEP are biomarkers of distinct mechanisms that may contribute to HF pathophysiology in such cohorts. The aim of this study was to determine whether growth differentiation factor-15 (GDF-15) and circulating neprilysin (cNEP) improve the diagnosis of congestive heart failure (HF) in patients on dialysis.
We compared circulating concentrations of NT-proBNP, GDF-15, and cNEP along with cNEP activity in patients on chronic dialysis without (n = 80) and with HF (n = 73), as diagnosed by clinical parameters and post-dialysis echocardiography. We used correlation, linear and logistic regression as well as receiver operating characteristic (ROC) analyses. Compared to controls, patients with HF had higher median values of NT-proBNP (16,216 [interquartile range, IQR = 27739] vs. 2883  pg/mL, p < 0.001), GDF-15 (7512  vs. 6005  pg/mL, p = 0.014), but not cNEP (315  vs. 318  pg/mL, p = 0.818). Median cNEP activity was significantly lower in HF vs. controls (0.189 [0.223] vs. 0.257 [0.166] nmol/mL/min, p < 0.001). In ROC analyses, a multi-marker model combining clinical covariates, NT-proBNP, GDF-15, and cNEP activity demonstrated best discrimination of HF from controls (AUC = 0.902, 95% CI 0.857-0.947, p < 0.001 vs. base model AUC = 0.785).
We present novel comparative data on physiologically distinct circulating biomarkers for HF in patients on dialysis. cNEP activity but not concentration and GDF-15 provided incremental diagnostic information over clinical covariates and NT-proBNP and may aid in diagnosing HF in dialysis patients.
Is Serum Pregnancy-Associated Plasma Protein A Really a Potential Marker of Atherosclerotic Carotid Plaque Stability?
P.Heider N.Pfäffle J.Pelisek M.Wildgruber H.Poppert M.Rudelius, H. Eckstein
The search for markers predicting risk of plaque rupture in carotid atherosclerosis is still ongoing. Previous findings showed that pregnancy-associated plasma protein-A (PAPP-A) levels correlate with an adverse plaque morphology. However, the role of PAPP-A in plaque destabilization is still uncertain. Circulating PAPP-A levels were significantly higher in patients with unstable versus stable plaques and interestingly, in asymptomatic versus symptomatic patients. Present data confirmed the close relationship between expression of PAPP-A and plaque instability and furthermore correlated significantly with cap thickness.
Prognostic Utility of Growth Differentiation Factor-15 in Patients with Chronic Heart Failure
Tibor Kempf, Stephan von Haehling, Timo Peter, Tim Allhoff, Mariantonietta Cicoira, Wolfram Doehner, Piotr Ponikowski, Gerasimos S. Filippatos, Piotr Rozentryt, Helmut Drexler, Stefan D. Anker, Kai C. Wollert
J Am Coll Cardiol. 2007 Sep, 50 (11) 1054-1060.
It was recently shown that patients with chronic heart failure have increased circulating levels of the transforming growth factor-β–related cytokine growth differentiation factor (GDF)-15. The prognostic relevance of GDF-15 in heart failure has never been investigated. Shown here in a cohort of 455 patients with chronic heart failure, the risk of death during follow-up was closely related to the levels of GDF-15 at baseline. Growth differentiation factor 15 emerged as an independent predictor of mortality and added prognostic information to New York Heart Association functional class, left ventricular ejection fraction, and amino-terminal pro–B-type natriuretic peptide. Our study identifies GDF-15 as a new biomarker in chronic heart failure that provides prognostic information beyond established clinical and biochemical markers.
GDF‐15 prevents platelet integrin activation and thrombus formation
J. Rossaint D. Vestweber, A. Zarbock
International Society on Thrombosis and Haemostasis Volume11, Issue2 February 2013 335-344
Integrin‐mediated platelet function plays an important role in primary hemostasis. Growth‐differentiation factor 15 (GDF‐15) has been shown to inhibit β2‐integrin activation in leukocytes. Investigation was of the effect of GDF‐15 on platelet integrin activation in vitro and in different in vivo models of thrombus formation.
GDF‐15 specifically inhibits platelet integrin activation. These findings may have profound clinical implications for the treatment of hemostatic conditions involving platelets. In conclusion, our results indicate a crucial role for GDF‐15 in preventing agonist‐induced platelet integrin activation leading to diminished platelet in response to pathologic stimuli. The newly identified pathophysiological role of GDF‐15 in regulating the activation state of β1‐ and β3‐integrins on platelets may have profound clinical implications and a promising potential for the development of new treatment strategies and warrants further research within this field.
Growth Differentiation Factor 15 in Heart Failure: An Update
Kai C. Wollert & Tibor Kempf
Curr Heart Fail Rep 9, 337–345 (2012). https://doi.org/10.1007/s11897-012-0113-9
Growth differentiation factor 15 (GDF-15) is a stress-responsive cytokine expressed in the cardiovascular system. GDF-15 is emerging as a biomarker of cardiometabolic risk and disease burden. GDF-15 integrates information from cardiac and extracardiac disease pathways that are linked to the incidence, progression, and prognosis of heart failure (HF). Increased circulating levels of GDF-15 are associated with an increased risk of developing HF in apparently healthy individuals from the community. After an acute coronary syndrome, elevated levels of GDF-15 are indicative of an increased risk of developing adverse left ventricular remodeling and HF. In patients with established HF, the levels of GDF-15 and increases in GDF-15 over time are associated with adverse outcomes. The information provided by GDF-15 is independent of established risk factors and cardiac biomarkers, including BNP. More studies are needed to elucidate how the information provided by GDF-15 can be used for patient monitoring and formulating treatment decisions. Further understanding of the pathobiology of GDF-15 may lead to the discovery of new treatment targets in HF.
Growth Differentiation Factor 15, a Marker of Oxidative Stress and Inflammation, for Risk Assessment in Patients With Atrial Fibrillation
Insights From the Apixaban for Reduction in Stroke and Other Thromboembolic Events in Atrial Fibrillation (ARISTOTLE) Trial
Lars Wallentin , Ziad Hijazi, Ulrika Andersson, John H. Alexander, Raffaele De Caterina, Michael Hanna, John D. Horowitz, Elaine M. Hylek, Renato D. Lopes, Signild Åsberg, Christopher B. Granger, and Agneta Siegbahn
Growth differentiation factor 15 (GDF-15), high-sensitivity troponin, and N-terminal pro-brain natriuretic peptide levels are predictive of death and cardiovascular events in healthy elderly subjects, patients with acute coronary syndrome, and patients with heart failure. High-sensitivity troponin I and N-terminal pro-brain natriuretic peptide are also prognostic in patients with atrial fibrillation. We evaluated the prognostic value of GDF-15 alone and in addition to clinical characteristics and other biomarkers in patients with atrial fibrillation. The identification of GDF-15 as a biomarker independently related to major bleeding might lead to both improved risk stratification and a better understanding of the underlying causes of bleeding during anticoagulant treatment. GDF-15 is a divergent member of the transforming growth factor-β family that can be secreted from a broad range of cells, for example, cytokine secreted from adipocytes and myocytes in response to, and maybe protecting against, stress such as cellular ischemia and mechanical and oxidative stress. Plasma levels of GDF-15 are increased in response to inflammation and may be involved in maintaining the inflammatory activity.These experimental data and the results from this and other clinical studies suggest a link–-protective or harmful–-between GDF-15 and cellular stress as supported by the associations with age, diabetes mellitus, renal disease, smoking, congestive heart failure, and biomarkers of cardiac and renal dysfunction and inflammation. The understanding of the GDF-15 is limited because the GDF-15 receptor and the involved signaling pathways are unknown. Currently, the level of GDF-15 may to be interpreted mainly as an integrative signal of severity of disease in several different pathological conditions. In the present study, the associations between the GDF-15 level and the clinical risk factors and biomarkers of cardiac and renal dysfunction seemed to explain the relations between the GDF-15 level and ischemic stroke. However, as in other clinical studies, an independent relation between the GDF-15 level and mortality remained, indicating the importance of an underlying cellular process, which currently might be detected only by the GDF-15 elevation. The independent association between GDF-15 and the risk of bleeding confirmed our recent publication of the same relationship in patients treated with dual antiplatelet treatment after acute coronary syndrome in the Platelet Inhibition and Patient Outcomes (PLATO) trial.36 The independent relation between the GDF-15 level and bleeding in the present trial was seen in relation to major and clinically relevant bleeding and trended in the same direction for hemorrhagic stroke. The cause of the association between GDF-15 and the risk of bleeding might be that GDF-15 is increased at cellular stress and cellular vulnerability, which might be associated with an increased risk of bleeding at different kinds of tissue damage.
Elevated Plasma Plasminogen Activator Inhibitor Type-1 is an Independent Predictor of Coronary Microvascular Dysfunction in Hypertension
by Naya, Masanao; Tsukamoto, Takahiro; Inubushi, Masayuki; Morita, Koichi; Katoh, Chietsugu; Furumoto, Tomoo; Fujii, Satoshi; Tsutsui, Hiroyuki; Tamaki, Nagara
Circulation Journal, 2007, Volume 71, Issue 3
Elevated plasma plasminogen activator inhibitor-1 (PAI-1) is related to cardiovascular events, but its role in subclinical coronary microvascular dysfunction remains unknown. Thus, in the present study it was investigated whether elevated plasma PAI-1 activity is associated with coronary microvascular dysfunction in hypertensive patients. Thirty patients with untreated essential hypertension and 10 age-matched healthy controls were studied prospectively. Myocardial blood flow (MBF) was measured by using 15O-water positron emission tomography. Clinical variables associated with atherosclerosis (low-density lipoprotein-cholesterol, high-density lipoprotein (HDL)-cholesterol, triglyceride, homeostasis model assessment (HOMA-IR), and PAI-1 activity) were assessed to determine their involvement in coronary microvascular dysfunction. Adenosine triphosphate (ATP)-induced hyperemic MBF and coronary flow reserve (CFR) were significantly lower in hypertensive patients than in healthy controls. (ATP-induced MBF: 2.77±0.82 vs 3.49±0.71 ml · g-1 · min-1; p<0.02 and CFR: 2.95 ±1.06 vs 4.25±0.69; p<0.001). By univariate analysis, CFR was positively correlated with HDL-cholesterol (r=0.46, p<0.02), and inversely with HOMA-IR (r=-0.39, p<0.05) and PAI-1 activity (r=-0.61, p<0.001). By multivariate analysis, elevated PAI-1 activity remained a significant independent determinant of diminished CFR.
Elevated plasma PAI-1 activity is a major independent predictor of coronary microvascular dysfunction, as measured by 15O-water PET with ATP infusion in hypertensive patients. The present study adds evidence that diminished fibrinolysis contributes to coronary microvascular dysfunction and the pathobiological pathways of subclinical early coronary atherosclerosis in the setting of hypertension. Plasma PAI-1 measurement may help to identify hypertensive patients at high risk of developing coronary atherosclerosis.
Syndecan-1: A Critical Mediator in Cardiac Fibrosis
by Frangogiannis, Nikolaos G
Hypertension (Dallas, Tex.: 1979), 02/2010, Volume 55, Issue 2
Cardiac fibrosis is characterized by net accumulation of extracellular matrix in the myocardium and is an integral component of most cardiac pathological conditions. Fibrotic remodeling of the ventricle has profound consequences on cardiac function. Increased deposition of interstitial collagen in the perimysial space is initially associated with a stiffer ventricle and diastolic dysfunction. At a later stage, accumulation of extracellular matrix proteins in the cardiac interstitium activates proteolytic pathways leading to the development of ventricular dilation and systolic failure. Disturbance of the matrix network in the fibrotic heart may cause systolic dysfunction through several distinct mechanisms. First, loss of fibrillar collagen may impair transduction of cardiomyocyte contraction into myocardial force development resulting in uncoordinated contraction of cardiomyocyte bundles. Second, disruption of key interactions between endomysial matrix proteins (e.g., laminin and collagen) and their receptors in cardiomyocytes may promote cardiomyocyte death.1 Finally, fibrosis may result in sliding displacement (slippage) of cardiomyocytes leading to a decrease in the number of muscular layers in the ventricular wall and subsequent left ventricular dilation. Beyond its effects on cardiac function, fibrotic ventricular remodeling also promotes arrhythmogenesis through impaired anisotropic conduction and subsequent generation of reentry circuits.
The intriguing effects of syndecan-1 on TGF- and angiotensin II–mediated activation of fibroblasts raise an important question. What is the molecular basis for the observed effects of syndecan-1 on angiotensin II/TGF- signaling? Although the mechanisms for these effects have not been explored, several possibilities should be considered (Figure). First, syndecan-1 may regulate TGF-–induced matrix synthesis by modulating expression of TGF- receptors; such effects have been demonstrated for syndecan-2.10 Second, syndecan-1 may regulate the availability and activity of TGF- in vivo. Third, interactions between syndecan-1 and the TGF- receptors may result in direct modulation of TGF-/Smad2/3 signaling. Because syndecans appear to be critically involved in regulating fundamental pathways in tissue injury, repair, and fibrosis, dissection of their role in the injured heart will undoubtedly provide new insight into the mechanistic basis of heart disease.
B-type Natriuretic Peptide is an Independent Predictor of Endothelial Function in Man
by Pauriah, M; Khan, F; Lim, T K; Elder, D H; Godfrey, V; Kennedy, G; Belch, J; Booth, N A; Struthers, A D; Lang, Chim C
Clinical science (London, England: 1979), 09/2012, Volume 123, Issue 5
BNP (B-type natriuretic peptide) has been reported to be elevated in preclinical states of vascular damage. To elucidate the relationship between plasma BNP and endothelial function, we have investigated the relationship between BNP and endothelial function in a cohort of subjects comprising healthy subjects as well as at-risk subjects with cardiovascular risk factors. To also clarify the relative contribution of different biological pathways to the individual variation in endothelial function, we have examined the relationship between a panel of multiple biomarkers and endothelial function. A total of 70 subjects were studied (mean age, 58.1±4.6 years; 27% had a history of hypertension and 18% had a history of hypercholesterolemia). Endothelium-dependent vasodilatation was evaluated by the invasive ACH (acetylcholine)-induced forearm vasodilatation technique. A panel of biomarkers of biological pathways was measured: BNP, hemostatic factors PAI-1 (plasminogen-activator inhibitor 1) and tPA (tissue plasminogen activator), inflammatory markers, including cytokines [hs-CRP (high sensitive C-reactive protein), IL (interleukin)-6, IL-8, IL-18, TNFα (tumor necrosis factor α) and MPO (myeloperoxidase] and soluble adhesion molecules [E-selectin and sCD40 (soluble CD40)]. The median BNP level in the study population was 26.9 pg/ml. Multivariate regression analyses show that age, the total cholesterol/HDL (high-density
lipoprotein) ratio, glucose and BNP were independent predictors of endothelial function, and BNP remained an independent predictor (P=0.009) in a binary logistic regression analysis using FBF (forearm blood flow) as a dichotomous variable based on the median value. None of the other plasma biomarkers was independently related to ACH-mediated vasodilatation. In a strategy using several biomarkers to relate to endothelial function, plasma BNP was found to be an independent predictor of endothelial function as assessed by endothelium-dependent vasodilatation in response to ACH.
In a strategy using several biomarkers to relate to endothelial function assessed by the invasive ACH induced forearm vasodilatation technique, plasma BNP was found to be an independent predictor of endothelial function.
Early Onset Preeclampsia Is Associated With Glycocalyx Degradation and Reduced Microvascular Perfusion.
Weissgerber TL, Garcia-Valencia O, Milic NM, Codsi E, Cubro H, Nath MC, White WM, Nath KA, Garovic VD.
Background The endothelial glycocalyx is a vasoprotective barrier between the blood and endothelium. We hypothesized that glycocalyx degradation is present in preeclampsia, a pregnancy-specific hypertensive disorder characterized by endothelial dysfunction and activation. Methods and Results We examined the sublingual glycocalyx noninvasively using sidestream dark field imaging in the third trimester among women with normotensive pregnancies (n=73), early (n=14) or late (n=29) onset preeclampsia, or gestational diabetes mellitus (n=21). We calculated the width of the glycocalyx that was permeable to red blood cells (called the perfused boundary region, a measure of glycocalyx degradation) and the percentage of vessels that were filled with red blood cells ≥50% of the time (a measure of microvascular perfusion). In addition, we measured circulating levels of glycocalyx components, including heparan sulfate proteoglycans, hyaluronic acid, and SDC1 (syndecan 1), in a subset of participants by ELISA . Repeated-measures ANOVA was performed to adjust for vessel diameter and caffeine intake. Women with early onset preeclampsia showed higher glycocalyx degradation, indicated by a larger perfused boundary region (mean: 2.14 [95% CI, 2.05-2.20]), than the remaining groups (mean: normotensive: 1.99 [95% CI, 1.95-2.02], P=0.002; late-onset preeclampsia: 2.01 [95% CI, 1.96-2.07], P=0.024; gestational diabetes mellitus: 1.97 [95% CI, 1.91-2.04], P=0.004). The percentage of vessels that were filled with red blood cells was significantly lower in early onset preeclampsia. These structural glycocalyx changes were accompanied by elevated plasma concentrations of the glycocalyx components, heparan sulfate proteoglycans and hyaluronic acid, in early onset preeclampsia compared with normotensive pregnancy. Conclusions Glycocalyx degradation and reduced microvascular perfusion are associated with endothelial dysfunction and activation and vascular injury in early onset preeclampsia.
Association of pregnancy-associated plasma protein A and vascular endothelial growth factor with pregnancy-induced hypertension.
Zhang Z, Xu H, Liu X, Li P, Du W, Han Q.
The present study aimed to evaluate changes of pregnancy-associated plasma protein A (PAPP-A) and vascular endothelial growth factor (VEGF) in pregnancy-induced hypertension (PIH). A total of 105 cases (observation group) with complete data that underwent delivery and suffered from PIH in The Affiliated Hospital of Xuzhou Medical University from February 2015 to February 2017 were retrospectively analyzed. The observation group was further divided into the mild observation and severe observation groups according to severity degree of the disease. Another 65 asymptomatic pregnant women were recruited as the healthy control group. Basic data, obstetric data, PAPP-A and VEGF and data of perinatal infants were compared and analyzed. The Logistic regression model was adopted to screen out risk factors for PIH. In the observation group, the rate of periodic antenatal care was lower, and there were more primigravidas and housewives, with lower education level and economic income (P<0.05). In the observation group, the occurrence rates of placental abruption as well as turbid and bloody amniotic fluid were higher than those in the healthy control group(P<0.05). The neonatal birth weight was lower in the observation group than that in the healthy control group, while the occurrence rates of neonatal department transfer, small for gestational age (SGA), neonatal asphyxia and survival rates of perinatal infants were higher (P<0.05). PAPP-A levels at 34-40 gestational weeks in the observation group were significantly higher than those in the healthy control group (P<0.05). VEGF levels were lower than those in the healthy control group (P<0.05). Multivariate analysis revealed that high PAPP-A value [odds ratio (OR)=3.736] and identity of housewife (OR=2.514) were risk factors for PIH, while high VEGF value (OR=5.258), non-primigravid (OR=2.173), higher economic income (OR=4.162) and periodic antenatal care (OR=1.201) were regarded as protective factors. Therefore, enhancement of gestational management, early discovery and early treatment are critical for improving the prognosis of pregnant women and infants.
Attenuating Pulmonary Hypertension by Protecting the Integrity of Glycocalyx in Rats Model of Pulmonary Artery Hypertension.
Guo J, Yang ZC, Liu Y.
The endothelial glycocalyx has been proved to be a polysaccharide protein complex covering the surface of vascular endothelial cells, playing an important role in vascular permeability, blood flow shear stress induction, and prevention of endothelial cell adhesion. The pathogenesis of PAH includes pulmonary arterial endothelial cell dysfunction and pulmonary arterial smooth muscle cell (PASMCs) proliferation. Based on the physicochemical properties of endothelial glycocalyx involving pathogenesis of pulmonary hypertension. We hypothesized that the endothelial glycocalyx is involved in the development of pulmonary hypertension; pulmonary hypertension can be regulated by protecting the integrity of glycocalyx. Expression of glycocalyx markers including heparin sulfate proteoglycan (HSPG), hyaluronan (HA), and syndecan-1 (SDC-1) was detected in monocrotaline (MCT)-induced PAH in rats and these components were detected when the PAH rats were treated with heparin that protected the role of glycocalyx. Results showed that plasma levels of HSPG, HA, and SDC-1 were increased in MCT group when compared with control group. However, rats in treatment group showed reduced levels of HSPG, HA, and SDC-1. Expression of HSPG, HA, and SDC-1 in pulmonary arteries was also reduced in MCT group when compared with those in the control group. By contrast, expression of HSPG, HA, and SDC-1 in pulmonary arteries increased in treatment group. In conclusion, destruction of glycocalyx was involved in the development of pulmonary hypertension. Pulmonary hypertension can be regulated by protecting the integrity of glycocalyx.
Protection of glycocalyx decreases platelet adhesion after ischemia/reperfusion: an animal study.
Chappell D, Brettner F, Doerfler N, Jacob M, Rehm M, Bruegger D, Conzen P, Jacob B, Becker BF.
Eur J Anaesth. 2014;31:474–81.
Strategies targeting the protection of the vascular barrier, in particular the endothelial glycocalyx, are subjects of current research. Antithrombin III and hydrocortisone have been shown to reduce shedding of the glycocalyx following ischemia/reperfusion. Platelet adhesion to endothelial cells is one consequence of ischemia/reperfusion. Our goal was to evaluate the effect of pharmacological protection of the glycocalyx on platelet adhesion. DESIGN: An experimental interventional animal study. Eighty male guinea pigs (250 to 300 g) were used for the experiment. The effect of preischemic treatment with hydrocortisone 10 μg ml (-1) or antithrombin 1 IU ml on adherence of platelets was evaluated in isolated, beating guinea pig hearts (Langendorff model). Hearts were subjected to warm ischemia (20 min at 37 °C) and consecutive reperfusion. Platelets were injected at the beginning of reperfusion via the aortic cannula and platelet concentration was measured in the effluent (after passing through the coronary vascular system). Ischemia and reperfusion led to significant shedding of the endothelial glycocalyx. Coronary venous release of syndecan-1 increased nine-fold, and heparan sulphate showed a 20.3-fold increase after ischemia/reperfusion (both P < 0.01). Pretreatment with hydrocortisone or antithrombin III reduced endothelial glycocalyx shedding significantly (P < 0.05). Adherence of platelets to the coronary vascular bed increased more than 2.5-fold when they were injected during reperfusion. About 40% of this increase was blocked by pretreatment of hearts with hydrocortisone or antithrombin. Pretreatment with hydrocortisone or antithrombin III can reduce platelet adhesion during reperfusion after warm ischemia by protection of the endothelial glycocalyx. Pretreatment with hydrocortisone or antithrombin III can reduce platelet adhesion during reperfusion after warm ischemia by protection of the endothelial glycocalyx.
Reactive Oxygen Species Mediate Modification of Glycocalyx During Ischemia-Reperfusion Injury
by Rubio-Gayosso, Ivan; Platts, Steven H; Duling, Brian R
American journal of physiology. Heart and circulatory physiology, 06/2006, Volume 290, Issue 6
The glycocalyx (Gcx) is a complex and poorly understood structure covering the luminal surface of endothelial cells. It is known to be a determinant of vascular rheology and permeability and may be a key control site for the vascular injuries caused by ischemia-reperfusion (I/R). We used intravital-microscopy to evaluate the effects of I/R injury on two properties of Gcx in mouse cremasteric micro vessels: exclusion of macromolecules (anionic-dextrans) and intracapillary distribution of red blood cells (RBC). In this model, the Gcx is rapidly modified by I/R injury with an increase in 70-kDa anionic-dextran penetration without measurable effect on the penetration of 580-kDa anionic-dextran or on RBC exclusion. The effects of I/R injury appear to be mediated by the rapid production of reactive oxygen species (ROS) because they are ameliorated by the addition of exogenous superoxide dismutase-catalase. Intravenous application of allopurinol or heparin also inhibited the effects of I/R injury, and we interpret efficacy of allopurinol as evidence for a role for xanthine-oxidoreductase (XOR) in the response to I/R injury. Heparin, which is hypothesized to displace XOR from a heparin-binding domain in the Gcx, reduced the effects of I/R. The effects of I/R injury were also partially prevented or fully reversed by the intravascular infusion of exogenous hyaluronan. These data demonstrate: 1) the liability of Gcx during I/R injury; 2) the importance of locally produced ROS in the injury to Gcx; and 3) the potential importance of heparin-binding sites in modulating the ROS production. Our findings further highlight the relations between glycosaminoglycans and the pathophysiology of Gcx in vivo.
Understanding the mechanisms involved in the regulation or the modification of the Gcx in response to pathophysiological stimuli will be a very complicated task. The present work contributes by showing that I/R-I induces an alteration in the interaction of the Gcx with the Dex70-FITC, as demonstrated by the reduction in the exclusion zone of this macromolecule, but without effect in the exclusion of larger macromolecules, Dex 580-FITC, and RBC. This reduction is mediated by the production of ROS generated by XOR, an enzyme that is bound to the Gcx through its HBD. This effect could be dependent on the reorganization or loss of Gcx hyaluronan, because the administration of exogenous hyaluronan is able to prevent and reverse the I/R-I-induced effects. As this study demonstrates, hyaluronan could be a key element in the response of I/R-I and that the close interaction between GAGs and mediators of the signaling pathway is critical in the pathophysiology of the Gcx in vivo.
Endothelial glycocalyx as an additional barrier determining extravasation of 6% hydroxyethyl starch or 5% albumin solutions in the coronary vascular bed.
Rehm M, Zahler S, Lotsch M, Welsch U, Conzen P, Jacob M, Becker BF.
The impact on the endothelial glycocalyx for the extravasation of colloidal infusion solutions has not been investigated sufficiently. Isolated guinea pig hearts were perfused with Krebs-Henseleit buffer in a Langendorff mode. Solutions of 0.9% saline, 5% albumin (70 kd), or 6% hydroxyethyl starch (200 kd) were infused into the coronary system for 20 min at a rate of one third of the coronary flow, also during reperfusion after 15 min of ischemia, and after enzymatic digestion of the endothelial glycocalyx by heparinase. Net coronary fluid filtration was assessed directly by measuring the formation of transudate on the epicardial surface, and solute extravasation was assessed by measuring albumin and hydroxyethyl starch in the coronary effluent and transudate. Hearts were perfusion fixed to visualize the endothelial glycocalyx using transmission electron microscopy. RESULTS: Only infusion of hydroxyethyl starch, not infusion of albumin, significantly decreased net coronary fluid filtration. Heparinase application without ischemia increased coronary leak by 25% but did not accelerate the passage of colloids. Ischemia alone did not alter permeability. However, there was a large (approximately +200%), transient (approximately 4 min) increase in permeability for water, albumin, and hydroxyethyl starch after ischemia with heparinase application. Also, histamine (10 m) only increased permeability after pretreatment of the hearts with heparinase. The thickness of the glycocalyx after colloid administration was 0.2-0.3 micron. No glycocalyx could be detected after application of heparinase. The endothelial glycocalyx acts as a competent barrier for water and colloids. Only after its destruction do changes in endothelial morphology (postischemic reperfusion or histamine application) become effective determinants of coronary extravasation.
Glycocalyx protection reduces leukocyte adhesion after ischemia/reperfusion.
Chappell D, Dorfler N, Jacob M, Rehm M, Welsch U, Conzen P, Becker BF.
Adhesion of polymorphonuclear neutrophils (PMN) to coronary endothelium is a key event for cardiac ischemia/reperfusion injury. Adhesion molecules are normally harbored within the glycocalyx, clothing every healthy vascular endothelium, but shed by ischemia/reperfusion. Our aim was to show whether protection of the glycocalyx with either hydrocortisone or antithrombin can reduce postischemic leukocyte adhesion. Isolated guinea pig hearts, perfused with Krebs-Henseleit buffer, were subjected to 20 min of warm (37 degrees C) no-flow ischemia and consecutive 10 min of reperfusion, either in the absence or presence of hydrocortisone (10 microg/mL) or antithrombin (1 U/mL). An intracoronary bolus of 3 x 10 PMN was applied at the end of reperfusion but without prior contact to the drugs. The sequestration of PMN was calculated from the difference between coronary input and output of cells. Expression of the integrin CD11b on PMN was measured before and after coronary passage. Ischemia/reperfusion induced severe degradation of the glycocalyx (coronary venous syndecan-1 release, 171 +/- 15 ng/g heart vs. basal, 19 +/- 2 ng/g; heparan sulfate, 5.27 +/- 0.28 microg/g vs. basal, 0.26 +/- 0.06 microg/g) and increased PMN adhesion (38.1% +/- 3.5% vs. basal, 11.7% +/- 3.1%). Hydrocortisone and antithrombin both not only reduced glycocalyx shedding (syndecan-1 release, 34 +/- 6 ng/g and 26 +/- 5 ng/g; heparan sulfate, 1.96 +/- 0.24 microg/g and 1.28 +/- 0.2 microg/g, respectively), but also PMN adhesion (17.3% +/- 2.2% and 25.4% +/- 3.3%, respectively) after ischemia/reperfusion. Electron microscopy revealed a mostly intact coronary glycocalyx after pretreatment with either drug. Activation of PMN upon coronary passage was not influenced. Preservation of the glycocalyx mitigates postischemic PMN adhesion. Preconditioning with either hydrocortisone or antithrombin should, thus, alleviate vascular leakage, tissue edema, and inflammation.
Mulivor AW and Lipowsky HH.
Am J Physiol Heart Circ Physiol 2004; 286: H1672-680.
Alterations in the composition of the glycocalyx of venular endothelium in postcapillary venules (rat mesentery) were explored in models of inflammation and ischemia-reperfusion injury. Lectins were covalently linked to fluorescently labeled microspheres (0.1-microm diameter) or directly labeled with FITC. Adhesion of lectins specific for glucose and galactose residues of glycosaminoglycans (GAGs) and other components of the endothelial glycocalyx decreased dramatically after superfusion of the mesentery with the chemoattractant N-formylmethionyl-leucyl-phenylalanine and during reperfusion after 60-min ischemia. These reductions were significantly attenuated by superfusion with pertussis toxin (PTX), suggesting that shedding of glycocalyx was mediated by G proteins. Adhesion of microspheres linked with antibody for syndecan-1, a major proteoglycan to which GAGs are bound, revealed increased labeling as GAGs were lost and permitted greater numbers of spheres to adhere to the protein core, which was not shed. Induction of ischemia by occluding proximal micro vessels for 60 min resulted in a 40% increase in galactosaminoglycans and a 15% increase in glucosaminoglycans on the endothelium, which was not inhibited by PTX. Reperfusion of vessels led to a rapid loss of GAGs that was inhibited by pretreatment with PTX, with 40% of galactosaminoglycans and 25% of glucosaminoglycans accumulated being removed by G protein-mediated shedding and the remainder freely convected away by fluid shear. We conclude that the composition of the glycocalyx results from a balance of the rate of biosynthesis of GAGs by the endothelial cell and their shedding, which may be mediated by intracellular and/or membrane-bound proteases or lyases released or activated by G protein signaling.
The Transforming Growth Factor-β Superfamily Member Growth-Differentiation Factor-15 Protects the Heart from Ischemia/Reperfusion Injury
Tibor Kempf, Matthias Eden, Jens Strelau, Marian Naguib, Christian Willenbockel, Jörn Tongers, Jörg Heineke, Daniel Kotlarz, Jian Xu, Jeffery D. Molkentin, Hans W. Niessen, Helmut Drexler, and Kai C. Wollert
Data from the Women’s Health Study show that serum levels of growth-differentiation factor-15 (GDF-15), a distant member of the transforming growth factor-β superfamily, are an independent risk indicator for adverse cardiovascular events. However, the cellular sources, upstream regulators, and functional effects of GDF-15 in the cardiovascular system have not been elucidated. We have identified GDF-15 by cDNA expression array analysis as a gene that is strongly upregulated by nitrosative stress in cultured cardiomyocytes isolated from 1- to 3-day-old rats. GDF-15 mRNA and pro-peptide expression levels were also induced in cardiomyocytes subjected to simulated ischemia/reperfusion (I/R) via NO–peroxynitrite-dependent signaling pathways. GDF-15 was actively secreted into the culture supernatant, suggesting that it might exert autocrine/paracrine effects during I/R. To explore the in vivo relevance of these findings, mice were subjected to transient or permanent coronary artery ligation. Myocardial GDF-15 mRNA and pro-peptide abundance rapidly increased in the area-at-risk after ischemic injury. Similarly, patients with an acute myocardial infarction had enhanced myocardial GDF-15 pro-peptide expression levels. As shown by immunohistochemistry, cardiomyocytes in the ischemic area contributed significantly to the induction of GDF-15 in the infarcted human heart. To delineate the function of GDF-15 during I/R, Gdf-15 gene-targeted mice were subjected to transient coronary artery ligation for 1 hour followed by reperfusion for 24 hours. Gdf-15–deficient mice developed greater infarct sizes and displayed more cardiomyocyte apoptosis in the infarct border zone after I/R compared with wild-type littermates, indicating that endogenous GDF-15 limits myocardial tissue damage in vivo. Moreover, treatment with recombinant GDF-15 protected cultured cardiomyocytes from apoptosis during simulated I/R as shown by histone ELISA, TUNEL/Hoechst staining, and annexin V/propidium iodide fluorescence-activated cell sorting (FACS) analysis. Mechanistically, the prosurvival effects of GDF-15 in cultured cardiomyocytes were abolished by phosphoinositide 3-OH kinase inhibitors and adenoviral expression of dominant-negative Akt1 (K179M mutation). In conclusion, our study identifies induction of GDF-15 in the heart as a novel defense mechanism that protects from I/R injury.
Plasminogen Activator Inhibitor in Plasma: Risk Factor for Recurrent Myocardial Infarction
by Hamsten, Anders; Walldius, Göran; Szamosi, Alfred; Blombäck, Margareta; Faire, UlfDe; Dahlén, Gösta; Landou, Christian; Wiman, Björn
The Lancet, 1987, Volume 330, Issue 8549
Measurements of hemostatic function and metabolic and angiographic indices of risk were included in a prospective cohort study of variables predictive of recurrences within 3 years in 109 unselected men with a first myocardial infarction (MI) before the age of 45. In the course of follow-up, 16 patients had at least one reinfarction (fatal recurrences in 9 and nonfatal in 7) and 1 died suddenly. High plasma concentrations of the fast-acting plasminogen activator inhibitor were independently related to reinfarction along with dyslipoproteinaemia involving VLDL and HDL, poor left ventricular performance, and multiple-vessel coronary artery disease. Besides being independently associated with reinfarction in the present population, high triglyceride levels were possibly connected with a predisposition to thrombosis through a coexisting high level of plasminogen activator inhibitor. The data indicate that reduced fibrinolytic capacity due to increased plasma levels of the plasminogen activator inhibitor predisposes to reinfarction in a complex interplay with atherogenic factors, multiple coronary lesions, and compromised left ventricular function.
Impaired fibrinolytic capacity and increased fibrin formation associate with myocardial infarction
by K. Leander; M. Blombäck; H. Wallén; S. He
Thrombosis and Hemostasis, 06/2012, Volume 107, Issue 6
We assessed whether abnormality of hemostasis measured by a newly developed global method is associated with risk of a first myocardial infarction (MI). The global markers Coagulation activation profile (Cp), Fibrinolysis activation profile (Fp) and sum of fibrin optical density over time (Fibrin OD- sum) were determined in plasma from 800 MI cases and 1,123 controls included in the Stockholm Heart Epidemiology Program. Clot lysis time (CLT) was also determined based on raw data of fibrin OD from the global assay. Odds ratios (OR) of MI with 95% confidence intervals (CI) were calculated using logistic regression. A Fp value <10th percentile value in controls was significantly associated with increased MI risk; OR after multivariate adjustments for conventional cardiovascular risk factors 1.66 (95% CI 1.22–2.27). For an abnormally long CLT (>90th percentile value in controls) the adjusted OR of MI was 2.62 (95% CI 1.87–3.66) and for a high Fibrin OD-sum value (>90th percentile in controls) it was 1.86 (95% CI 1.37–2.53). A high Cp value was not significantly associated with MI. In conclusion, we found that abnormal hemostasis in platelet-poor plasma, reflected either as an attenuated fibrinolytic capacity or the resulting increase of fibrin formation, was associated with increased MI risk.
No-Reflow Phenomenon and Endothelial Glycocalyx of Microcirculation
by Maksimenko, Alexander V; Turashev, Askar D
Biochemistry research international, 2012, Volume 2012
The progress in reperfusion therapy dictated the necessity for developing new tools and procedures for adjacent/additional therapy of acute cardiovascular disorders. The adjacent therapy is targeted on the damage of the microcirculation, leading to the unfavorable prognosis for the patients. The no-reflow phenomenon holds special place in the multifactorial etiology of the microcirculation disorders, offering a new challenge in treating the patients associated with ST-segment elevation on ECG at myocardial infarction. One of the numerous causes of no-reflow, the influence of the endothelial glycocalyx of the microcirculation, is analyzed. The results obtained in the studies of the endothelial glycocalyx ultrastructure are generalized, the effect that the fragments of the glycocalyx glycosaminoglycans have on the function of the vascular wall is demonstrated. The trends in searching for correlations between the thickness of the capillary glycocalyx and the cardiovascular disease risk are noted.
One of the purposes of adjacent treatment is the damages of the microcirculation in acute coronary syndrome. The unfavorable prognosis for the patients without “optimal” reperfusion places them in the high-risk groups that have the no-reflow phenomenon in microcirculation. The clinical significance of successful treatment of this disorder offers a new challenge in treating the patients with AMI associated with ST-segment elevation. The studies of the no-reflow phenomenon reveal various causes for its development, paying, however, clearly insufficient attention to the role of EG. The study of the glycocalyx demonstrates that this spatial meshwork structure provides a protective function for the cell surface and that glycocalyx is capable to serve as a molecular filter and hydrodynamic partner in the interaction with cells and blood components. The action of chemical (enzymes, reactive oxygen species, changes of the medium pH value) and physical (shear stress, temperature, ultrasound, photo- and radio- emission, etc.) factors changes the structure of the glycocalyx, which is currently intensively studied and can influence the extent of the tissue perfusion. A diverse biological activity of EG fragments is also clearly evident and can substantially differ, depending on the molecular weight of these fragments. It is assumed that the glycocalyx, being connected to the cytoskeleton, serves as a mechanochemical transducer of the effect that blood circulation has on the processes of cell signaling. This may suggest a predictive role for the state of glycocalyx in the microcirculation. The path leading to our understanding of the mechanism for these effects is a very difficult way. However, an intention of following this path is justified by the prospective of successful treatment in the patients with complicated cardiovascular disorders.
Elevated plasma fibrinogen γ′ concentration is associated with myocardial infarction: effects of variation in fibrinogen genes and environmental factors.
M. Mannila, R. Lovely, S. Kazmierczak, P. Eriksson, A. Samnegard, D. Farrell, A. Hamsten, A. Silvera
j.1538-7836.2007.02406.x 02 April 2007
Fibrinogen γ′, a fibrinogen γ‐chain variant generated via alternative mRNA processing, has been associated with susceptibility to thrombotic disease. The present case–control study searched for potential determinants of the plasma fibrinogen γ′ concentration and examined the relationship between this variant and risk of myocardial infarction (MI). The Stockholm Coronary Artery Risk Factor study, comprising 387 postinfarction patients and 387 healthy individuals, was employed.
Plasma fibrinogen γ′ concentration influences the risk of MI, and this relationship seems to be strengthened by the presence of an elevated total plasma fibrinogen concentration and the FGG 9340T and FGA 2224G alleles.
Plasminogen activator inhibitor-1 (PAI-1) in children and adolescents with Type 1 Diabetes Mellitus: relation to diabetic micro-vascular complications and carotid intima media thickness.
by Adly, Amira Abdel Moneam; Elbarbary, Nancy Samir; Ismail, Eman Abdel Rahman; Hassan, Samar Reda
Journal of Diabetes and Its Complications, 2014, Volume 28, Issue 3
Plasminogen activator inhibitor-1 (PAI-1) is a fast-acting inhibitor of fibrinolysis that has been linked to increase risk of thrombosis. We determined PAI-1 levels in 80 children and adolescents with type 1 diabetes (T1DM) compared with 40 healthy controls as a potential marker for micro-vascular complications and assessed the relation to carotid intima media thickness (CIMT) as a synergistic risk factor for development of atherosclerosis.
Patients were divided into 2 groups according to micro-vascular complications. Hemoglobin A1c (HbA1c), urinary albumin excretion, fasting serum lipid profile and PAI-1 levels were measured. CIMT of the common carotid artery was assessed using high resolution ultrasonography.
PAI-1 levels were significantly elevated in the group with diabetes compared with control group (p<0.001). PAI-1 levels were also increased in patients with micro-vascular complications compared with those without (p<0.001). CIMT was significantly higher in patients, particularly those with micro-vascular complications than patients without complications or controls (p<0.001). Positive correlations were found between PAI-1 levels and random blood glucose, HbA1c, triglycerides, total cholesterol and CIMT (p<0.05).
Increased plasma PAI-1 may be involved in the state of hypo fibrinolysis in patients with T1DM leading to the occurrence of micro-vascular complications and increased risk of atherosclerosis.
Endothelial Glycocalyx Damage Coincides with Microalbuminuria in Type 1 Diabetes
by Max Nieuwdorp; Hans L. Mooij; Jojanneke Kroon; Bektas Atasever; Jos A.E. Spaan; Can Ince; Frits Holleman; Michaela Diamant; Robert J. Heine; Joost B.L. Hoekstra; John J.P. Kastelein; Erik S.G. Stroes; Hans Vink
Diabetes, 04/2006, Volume 55, Issue 4
Chronic hyperglycemia underlies microvascular complications in patients with type 1 diabetes. The mechanisms leading to these vascular complications are not fully understood. Recently, we observed that acute hyperglycemia results in endothelial glycocalyx damage. To establish whether glycocalyx is associated with microvascular damage, we performed glycocalyx perturbation volume measurements in type 1 diabetic patients with microalbuminuria (DM1-MA group; n = 7), without microalbuminuria (DM1-NA group; n = 7), and in age-matched control subjects (CON; n = 7). Systemic glycocalyx volume was determined comparing intravascular distribution volume of a glycocalyx-permeable tracer (dextran 40) to that of a glycocalyx-impermeable tracer (labeled erythrocytes). Sublingual capillaries were visualized using orthogonal polarization spectral microscopy to estimate microvascular glycocalyx. Patients and control subjects were matched according to age and BMI. Glycocalyx volume decreased in a stepwise fashion from CON, DM1-NA, and finally DM1-MA subjects (1.5 +/- 0.1, 0.8 +/- 0.4, and 0.2 +/- 0.1 l, respectively, P < 0.05). Microvascular glycocalyx in sublingual capillaries was also decreased in type 1 diabetes versus the control group (0.5 +/- 0.1 vs. 0.9 +/- 0.1 microm, P < 0.05). Plasma hyaluronan, a principal glycocalyx constituent, and hyaluronidase were increased in type 1 diabetes. In conclusion, type 1 diabetic patients are characterized by endothelial glycocalyx damage, the severity of which is increased in presence of microalbuminuria
Study limitations. Due to the relatively small sample size, we were unable to perform multivariate analysis in order to identify determinants predictive for glycocalyx damage. In fact, we chose to include a homogenous group of type 1 diabetic patients with or without microalbuminuria. The clear difference between patient categories and control subjects underscores potential clinical relevance of the observation. Secondly, the accuracy of glycocalyx volume estimates is largely determined by the accuracy of dextran 40 distribution volume estimates. Because of its small size and neutral charge, dextran 40 is also cleared from circulation. Therefore, we estimated the intravascular dextran 40 concentrations before vascular leakage or renal clearance by extrapolating dextran 40 concentrations to the time of injection. As can be appreciated from the clearance curve in Fig. 1B, the error of the estimated initial dextran 40 concentration is relatively small and will therefore have no major impact on the estimates of glycocalyx volume. Finally, whereas the microvasculature with its large endothelial surface area contains the majority of systemic glycocalyx volume, the macrovasculature determines the circulating blood volume. So, decreased glycocalyx volume with stable blood volume could also indicate selective loss of microvascular capillary volume. However, in the present study this scenario is highly unlikely. Thus, capillary density and dimension between diabetes without versus diabetes with microalbuminuria during OPS imaging were not significantly different, despite a significant decline in glycocalyx volume.
Clinical implications. The finding of a gradual reduction in glycocalyx volume in association with the presence of microalbuminuria in type 1 diabetic subjects emphasizes the generalized nature of glycocalyx perturbation in the development of diabetes-related microvascular disease. Further studies are needed to address whether glycocalyx perturbation indicates a poor vascular outcome and whether restoration of the glycocalyx is a valuable target to prevent vascular disease progression.
Loss of Endothelial Glycocalyx During Acute Hyperglycemia Coincides with Endothelial Dysfunction and Coagulation Activation in Vivo
by Max Nieuwdorp; Timon W. van Haeften; Mirella C.L.G. Gouverneur; Hans L. Mooij; Miriam H.P. van Lieshout; Marcel Levi; Joost C.M. Meijers; Frits Holleman; Joost B.L. Hoekstra; Hans Vink; John J.P. Kastelein; Erik S.G. Stroes
Hyperglycemia is associated with increased susceptibility to atherothrombotic stimuli. The glycocalyx, a layer of proteoglycans covering the endothelium, is involved in the protective capacity of the vessel wall. We therefore evaluated whether hyperglycemia affects the glycocalyx, thereby increasing vascular vulnerability. Because increased degradation of proteoglycans has previously been demonstrated in hyperglycemic conditions, the impact of hyperglycemia on the glycocalyx merits special interest. In the present study, we set out to evaluate the impact of hyperglycemia on the glycocalyx in healthy volunteers. We measured changes in the systemic glycocalyx volume before and 6 h after hyperglycemic-normoinsulinemic clamping. We simultaneously assessed changes in plasma hyaluronan, endothelial function, and coagulation parameters. The systemic glycocalyx volume was estimated by comparing the distribution volume of a glycocalyx permeable tracer (dextran 40) with that of a glycocalyx impermeable tracer (labeled erythrocytes) in 10 healthy male subjects. Measurements were performed in random order on five occasions: two control measurements, two measurements during normoinsulinemic hyperglycemia with or without N-acetylcysteine (NAC) infusion, and one during mannitol infusion. Glycocalyx measurements were taken together, these data indicate a potential role for glycocalyx perturbation in mediating vascular dysfunction during hyperglycemia.
Glycocalyx volume measurements: a critical review of tracer dilution methods for its measurement
by Michel, C.C; Curry, F.E
Microcirculation (New York, N.Y.: 1994), 04/2009, Volume 16, Issue 3
A clinical measure of endothelial glycocalyx structure would have great potential importance, because lesions of the glycocalyx may be the first changes to occur in diabetes and in a wide range of vascular diseases. A method recently described by Nieuwdorp et al. for estimating the volume of the luminal glycocalyx of the entire human vascular system would seem to be the first attempt to develop a measure of this kind. It is based on the tracer dilution principle, and this review considers the principles and conditions that underlie this method and the extent to which the conditions appear to have been fulfilled in this case. Their analysis raises two questions about 1) the estimation of the concentration of the tracer (dextran 40) at zero time and 2) the estimation of plasma volume, both of which can be answered by changes in experimental protocol. A third question, concerning the partition coefficient of the tracer between plasma and the fluid within the glycocalyx, cannot be answered at the present time, and until it has been resolved, glycocalyx volume cannot be estimated from the dilution of a macromolecular tracer.
Effect of Sulodexide on Endothelial Glycocalyx and Vascular Permeability in Patients with Type 2 Diabetes Mellitus
by Broekhuizen, L. N; Lemkes, B. A; Mooij, H. L; Meuwese, M. C; Verberne, H; Holleman, F; Schlingemann, R. O; Nieuwdorp, M; Stroes, E. S. G; Vink, H
Diabetologia, 2010, Volume 53, Issue 12
Abstract Aims/hypothesis Endothelial glycocalyx perturbation contributes to increased vascular permeability. In the present study we set out to evaluate whether: (1) glycocalyx is perturbed in individuals with type 2 diabetes mellitus, and (2) oral glycocalyx precursor treatment improves glycocalyx properties. Methods Male participants with type 2 diabetes (n=10) and controls (n=10) were evaluated before and after 2 months of sulodexide administration (200 mg/day). The glycocalyx dimension was estimated in two different vascular beds using side stream dark field imaging and combined fluorescein/indocyanine green angiography for sublingual and retinal vessels, respectively. Transcapillary escape rate of albumin (TERalb) and hyaluronan catabolism were assessed as measures of vascular permeability. Results Both sublingual dimensions (0.64 [0.57–0.75] μm vs 0.78 [0.71–0.85] μm, p< 0.05) were observed in the diabetes group. Conclusion/interpretation Type 2 diabetes is associated with glycocalyx perturbation and increased vascular permeability, which are partially restored following sulodexide administration. Further studies are warranted to determine whether long-term treatment with sulodexide has a beneficial effect on cardiovascular risk.
In conclusion, individuals with type 2 diabetes mellitus are characterized by a clear perturbation of the endothelial glycocalyx layer, which is thought to reflect increased vascular vulnerability. Oral sulodexide administration improves endothelial glycocalyx dimension to the same extent in two different vascular beds (sublingual and retinal), most likely because of enhanced precursor abundance for GAG synthesis. Improvement of glycocalyx dimension coincided with a trend toward normalized systemic vascular permeability and GAG metabolism. Collectively, the present findings imply that restoration of endothelial glycocalyx in humans may be a promising target to attenuate vascular dysfunction in type 2 diabetes mellitus. Further research is required to evaluate which treatment modalities are most likely to establish improvement in endothelial glycocalyx dimension. More importantly, prospective studies should address whether the concept holds true that endothelial glycocalyx improvement predicts long-term cardiovascular benefit in diabetes mellitus.
Nieuwdorp M., Mooij H., Kroon J., Atasever B., Spaan J., Ince C., Holleman F., Diamant M., Heine R., Hoekstra J., Kastelein J., Stroes E. and Vink H.
Diabetes 2006; 55: 1127-1132.
Chronic hyperglycemia underlies microvascular complications in patients with type 1 diabetes. The mechanisms leading to these vascular complications are not fully understood. Recently, we observed that acute hyperglycemia results in endothelial glycocalyx damage. To establish whether glycocalyx is associated with microvascular damage, we performed glycocalyx perturbation volume measurements in type 1 diabetic patients with microalbuminuria (DM1-MA group; n = 7), without microalbuminuria (DM1-NA group; n = 7), and in age-matched control subjects (CON; n = 7). Systemic glycocalyx volume was determined comparing intravascular distribution volume of a glycocalyx-permeable tracer (dextran 40) to that of a glycocalyx-impermeable tracer (labeled erythrocytes). Sublingual capillaries were visualized using orthogonal polarization spectral microscopy to estimate microvascular glycocalyx. Patients and control subjects were matched according to age and BMI. Glycocalyx volume decreased in a stepwise fashion from CON, DM1-NA, and finally DM1-MA subjects (1.5 +/- 0.1, 0.8 +/- 0.4, and 0.2 +/- 0.1 l, respectively, P < 0.05). Microvascular glycocalyx in sublingual capillaries was also decreased in type 1 diabetes versus the control group (0.5 +/- 0.1 vs. 0.9 +/- 0.1 micron, P < 0.05). Plasma hyaluronan, a principal glycocalyx constituent, and hyaluronidase were increased in type 1 diabetes. In conclusion, type 1 diabetic patients are characterized by endothelial glycocalyx damage, the severity of which is increased in presence of microalbuminuria.
The finding of a gradual reduction in glycocalyx volume in association with the presence of microalbuminuria in type 1 diabetic subjects emphasizes the generalized nature of glycocalyx perturbation in the development of diabetes-related microvascular disease. Further studies are needed to address whether glycocalyx perturbation indicates a poor vascular outcome and whether restoration of the glycocalyx is a valuable target to prevent vascular disease progression.
Endothelial Glycocalyx as a Shield Against Diabetic Vascular Complications: Involvement of Hyaluronan and Hyaluronidases.
Dogné S, Flamion B, Caron N.
The endothelial glycocalyx (EG), which covers the apical surface of the endothelial cells and floats into the lumen of the vessels, is a key player in vascular integrity and cardiovascular homeostasis. The EG is composed of PGs (proteoglycans), glycoproteins, glycolipids, and glycosaminoglycans, in particular hyaluronan (HA). HA seems to be implicated in most of the functions described for EG such as creating a space between blood and the endothelium, controlling vessel permeability, restricting leukocyte and platelet adhesion, and allowing an appropriate endothelial response to flow variation through mechanosensing. The amount of HA in the EG may be regulated by HYAL (hyaluronidase) 1, the most active somatic hyaluronidase. HYAL1 seems enriched in endothelial cells through endocytosis from the bloodstream. The role of the other main somatic hyaluronidase, HYAL2, in the EG is uncertain. Damage to the EG, accompanied by shedding of one or more of its components, is an early sign of various pathologies including diabetes mellitus. Shedding increases the blood or plasma concentration of several EG components, such as HA, heparan sulfate, and syndecan. The plasma levels of these molecules can then be used as sensitive markers of EG degradation. This has been shown in type 1 and type 2 diabetic patients. Recent experimental studies suggest that preserving the size and amount of EG HA in the face of diabetic insults could be a useful novel therapeutic strategy to slow diabetic complications. One way to achieve this goal, as suggested by a murine model of HYAL1 deficiency, may be to inhibit the function of HYAL1. The same approach may succeed in other pathological situations involving endothelial dysfunction and EG damage.
Plasminogen activator inhibitor-1, adipose tissue and insulin resistance.
Alessi MC1, Poggi M, Juhan-Vague I.
Plasminogen activator inhibitor (PAI)-1 is a physiological inhibitor of plasminogen activators (urokinase and tissue types) and vitronectin. It is synthesized by adipose tissue, and its levels in plasma are increased in obesity and reduced with weight loss. Circulating PAI-1 level predicts development of type 2 diabetes, suggesting that it may be causally related to development of obesity. A role for PAI-1 in development of obesity has only partially been established, however. This review summarizes current knowledge, gives context to developments thus far and discusses controversies.
In addition to its role in atherothrombosis, PAI-1 might be involved in adipose tissue development. PAI-1 is produced by ectopic fat depots under the influence of inducers. Among the most recently described inducers are inflammation, oxidative stress and circadian clock protein. PAI-1 may play several roles in contributing to obesity: through indirect effects on insulin signaling, by influencing adipocyte differentiation and by regulating recruitment of inflammatory cells within adipose tissue. These recent findings emphasize the involvement of PAI-1 in controlling the biology of adipose tissue; PAI-1 is an attractive new therapeutic target to retard the metabolic complications that accompany obesity.
Hypofibrinolysis and increased PAI-1 are linked to atherothrombosis via insulin resistance and obesity.
Juhan-Vague I, Alessi MC, Morange PE.
Plasminogen activator inhibitor 1 (PAI-1) is the primary physiological inhibitor of plasminogen activation in vivo. Circulating PAI-1 levels are elevated in patients with coronary heart disease and may play an important role in the development of atherothrombosis by decreasing fibrin degradation. Increased PAI-1 expression can also directly influence vessel wall remodeling. Prospective cohort studies have underlined the association between increased plasma PAI-1 levels and the risk of coronary events, but the predictive capacity of PAI-1 disappeared after adjustments for insulin resistance markers. The insulin resistance syndrome, which is characterized partly by obesity with visceral fat accumulation, is considered as a major regulator of PAI-1 expression. Recently, production of PAI-1 by adipose tissue, in particular by fat from omentum, has been evidenced, and it has been proposed that it could be responsible for the elevated plasma PAI-1 level observed in insulin resistance. The role of stroma cells, tumor necrosis factor (TNF)-alpha and transforming growth factor (TGF)-beta as possible enhancers of PAI-1 synthesis are presently emphasized. Glucocorticoids and insulin may also be implicated. Moreover, a weak genetic control of plasma PAI-1 concentration has been described in patients with high plasma levels of PAI-1. The role of PAI-1 in the development of adipose tissue metabolism is important to consider as PAI-1 -/- mice submitted to a high-fat diet showed changes in cell composition of adipose tissue and in plasma insulin and triglyceride levels.
Towards understanding the roles of heparan sulfate proteoglycans in Alzheimer's disease
by Zhang, Gan-lin; Zhang, Xiao; Wang, Xiao-min; Li, Jin-Ping
BioMed research international, 2014, Volume 2014
Alzheimer's disease (AD) is the most common form of dementia, characterized by progressive loss of memory and cognitive dysfunctions. A central pathological event of AD is accumulation and deposition of cytotoxic amyloid-[beta] peptide (A[beta]) in the brain parenchyma. Heparan sulfate proteoglycans (HSPGs) and the side chains heparan sulfate (HS) are found associated with A[beta] deposits in the brains of AD patients and transgenic animal models of AD. A growing body of evidence from in vitro and in vivo studies suggests functional roles of HSPG/HS in A[beta] pathogenesis. Although the question of "how and why HSPG/HS is co deposited with A[beta]?" remains, it is within reach to understand the mechanisms of the events. Recent progress by immunohistochemical examination with advanced antibodies shed light on molecular structures of HS code posited with A[beta]. Several recent reports have provided important new insights into the roles of HSPG in A[beta] pathogenesis. Particularly, experiments on mouse models revealed indispensable functions of HSPG in modulating A[beta]-associated neuroinflammation and clearance of A[beta] from the brain. Application of molecules to interfere with the interaction between HS and A[beta] peptides has demonstrated beneficial effects on AD mouse models. Elucidating the functions of HSPG/HS in A[beta] deposition and toxicity is leading to further understanding of the complex pathology of AD. The progress is encouraging development of new treatments for AD by targeting HS-A[beta] interactions.
Conclusion and Perspectives
Principle treatments for AD with regard to A[beta] pathology are to reduce production, improve clearance, and prevent aggregation of the pathological peptides. Considering that HS-A[beta] interaction contributes to every stage of the A[beta] pathogenesis in AD, including production, clearance and accumulation, aggregation, and toxicity of A[beta], it is rational to hypothesize that interfering HS-A[beta] interaction may have multiple beneficial effects. Earlier studies show that treatment with low molecular weight heparin (LMWH) reduced A[beta] burden in the brain of an AD mouse model overexpressing human A[beta]PP; the effect is probably that the LMWH competes with endogenous HS, blocking the HS-A[beta] interaction. This assumption is supported by our findings that the fragmentation of HS by overexpressed heparinase in mouse attenuated deposition of serum A amyloid (SAA; another amyloid protein). Though it is improper to use LMWH for treatment of AD, it is possible to apply nonanticoagulant LMWH or HS mimetics for the purpose. With the progress in characterization of HS molecular structures dissected from A[beta] plaques, it should be possible to design compounds mimic to the HS structures that interact with A[beta] to block its aggregation as well as to neutralize its toxicity. Moreover, targeting A[beta] producing enzymes, that is, BACE1 and [gamma]-secretase, constitutes one of the potential treatments for AD. Interestingly, HSPG has been found to modulate BACE activity, and efforts are being made to synthesize HS-oligosaccharides as inhibitors of BACE. Considering experimental and clinical evidences addressing the role of HS in A[beta] pathology, it is plausible to expect that novel treatments by targeting HS-A[beta] interaction may contribute to AD treatment and to improve effects of other treatments. Apart from designed synthesis of HS mimetics, natural anionic oligosaccharides, such as glycosaminoglycans isolated from marine animals and natural herbs, should also be explored for the potential to be developed as drug candidates for this particular application.
Pregnancy-Associated Plasma Protein-A Is Markedly Expressed by Monocyte-Macrophage Cells in Vulnerable and Ruptured Carotid Atherosclerotic Plaques
Giuseppe Sangiorgi, Alessandro Mauriello, Elena Bonanno, Claus Oxvig, Cheryl A. Conover, Michael Christiansen, Santi Trimarchi, Vincenzo Rampoldi, David R. Holmes, Robert S. Schwartz, Luigi Giusto Spagnoli
J Am Coll Cardiol. 2006 Jun, 47 (11) 2201-2211.
The study aim was to evaluate serologic expression of pregnancy-associated protein-A (PAPP-A) in patients affected by cerebrovascular accidents and to correlate it with histopathologic carotid plaque complexity. Little is known about PAPP-A expression in carotid atherosclerotic disease and whether this protein represents a marker of plaque vulnerability also in carotid district.
Seventy-two carotid plaques from patients submitted to surgical endarterectomy (19 who suffered a major stroke, 24 transient ischemic attack, and 29 asymptomatic) were evaluated. Serologic PAPP-A levels were determined by enzyme-linked immunoadsorbent assay. Plaques were divided in three groups based on histology: 1) stable (n = 38); 2) vulnerable (n = 13); 3) ruptured with thrombus (n = 14). Immunohistochemical staining for PAPP-A, smooth muscle cells, macrophages, and T-lymphocytes was performed in all cases. Real-time polymerase chain reaction assessed local PAPP-A production, and double immunofluorescence confocal microscopy (ICM) characterized cell type expressing PAPP-A. This study suggests that PAPP-A is a marker of carotid plaque destabilization and rupture. Further studies are necessary to determine if PAPP-A can represents a new target for stratifying the risk of cerebrovascular events.
Trauma-Induced Coagulopathy: Standard Coagulation Tests, Biomarkers of Coagulopathy, and Endothelial Damage in Patients with traumatic brain injury.
by Genét, Gustav Folmer; Johansson, Pär Ingemar; Meyer, Martin Abild Stengaard; Sølbeck, Sacha; Sørensen, Anne Marie; Larsen, Claus Falck; Welling, Karen Lise; Windeløv, Nis Agerlin; Rasmussen, Lars S; Ostrowski, Sisse Rye
Journal of Neurotrauma, 02/2013, Volume 30, Issue 4
It remains to be debated whether traumatic brain injury (TBI) induces a different coagulopathy than does non-TBI. This study investigated traditional coagulation tests, biomarkers of coagulopathy, and endothelial damage in trauma patients with and without TBI. Blood from 80 adult trauma patients was sampled (median of 68 min [IQR 48–88] post-injury) upon admission to our trauma center. Plasma/serum were retrospectively analyzed for biomarkers reflecting sympathoadrenal activation (adrenaline, noradrenaline), coagulation activation/inhibition and fibrinolysis (protein C, activated protein C, tissue factor pathway inhibitor, antithrombin, prothrombin fragment 1+2, thrombin/antithrombin complex, von Willebrand factor, factor XIII, d-dimer, tissue-type plasminogen activator, plasminogen activator inhibitor-1), immunology (interleukin [IL]6), endothelial cell/glycocalyx damage (soluble thrombomodulin, syndecan-1), and vasculogenesis (angiopoietin-1, -2). Patients were stratified according to: 1) isolated severe head/neck injuries (Abbreviated Injury Score [AIS]-head/neck≥3, AIS-other<3) (isoTBI); 2) severe head/neck and extracranial injuries (AIS-head/neck≥3, AIS-other>3) (sTBI+other); and 3) injuries without significant head/neck injuries (AIS-head/neck<3, including all AIS-other scores) (non-TBI). Twenty-three patients presented with isoTBI, 15 with sTBI+other and 42 with non-TBI. Acute coagulopathy of trauma shock, defined as activated partial thromboplastin time (APTT) and/or international normalized ratio (INR)>35 sec and>1.2, was found in 13%, 47%, and 5%, respectively (p=0.000). sTBI+other had significantly higher plasma levels of adrenaline, noradrenaline, annexin V, d-dimer, IL-6, syndecan-1, soluble thrombomodulin, and reduced protein C and factor XIII levels (all p<0.05). No significant biomarker differences were found between isoTBI and non-TBI patients. Injury Severity Scale (ISS) rather than the presence or absence of head/neck injuries determined the hemostatic and biomarker response to the injury. The coagulopathy identified thus reflected the severity of injury rather than its localization.
We found no significant difference in TIC pathophysiology whether patients had isoTBI or non-TBI, even when excluding patients with AIS-head/neck = 1–2 from the non-TBI group. On the basis of these findings, we propose that the hemostatic, vascular, and endothelial responses may be the same in isoTBI and non-TBI patients, and because of downstream effects from the sympathoadrenal response, mainly determined by the extracranial injuries.
Plasminogen activator inhibitor links obesity and thrombotic cerebrovascular diseases: The roles of PAI-1 and obesity on stroke.
Chen R, Yan J, Liu P, Wang Z, Wang C.
One of the global socioeconomic phenomena occurred during the last decades is the increased prevalence of obesity, with direct consequence on the risk of developing thrombotic disorders. As the physiological inhibitor of tissue plasminogen activator (tPA) and urokinase plasminogen activator (uPA), plasminogen activator inhibitor-1 (PAI-1) is well known for its role in fibrinolysis. More and more evidences have shown that PAI-1 involves in physiopathologic mechanisms of many diseases and metabolic disorder. Increased serum level of PAI-1 has been observed in obesity and it also contributes to the development of adipose tissue and then has effects on obesity. Meantime, obesity affects also the PAI-1 levels. These evidences indicate the complicated interaction between PAI-1 and obesity. Many clinic studies have confirmed that obesity relates to the stroke outcome although there are many contradictory results. Simultaneously, correlation is found between plasma PAI-1 and thrombotic cerebrovascular diseases. This article reviews contemporary knowledge regarding the complex interplay of obesity, PAI-1 and stroke.
Prognostic and Clinical Significance of Syndecan-1 in Colorectal Cancer: a Meta-Analysis
by Wei, Hao-Tang; Guo, Er-Na; Dong, Bao-Guo; Chen, Li-Sheng
BMC gastroenterology, 10/2015, Volume 15, Issue 1
Syndecan-1 plays a vital role in the suppression, transformation, and migration of several cancer types, including colorectal cancer (CRC). However, the prognostic and clinical significance of syndecan-1 in CRC remains conflicting. Therefore, we performed a meta-analysis to clarify this relationship. The authors analysis is the first to clarify the relationship between syndecan-1 expression and clinical parameters and prognosis in CRC. The analysis was able to overcome the small sample size of individual studies, thereby enhancing statistical power and providing a more reliable estimation of these associations. In addition, the results indicated the absence of significant publication bias, suggesting the robustness of the results. To date, IHC is the most common method used to detect the expression of cytokines at the protein level, while other methods, such as PCR, that detect expression at the gene level have also been used widely. These methods are mutually complementary. In our study, we chose IHC because most studies used this method to detect the expression of syndecan-1, and hence we could obtain a large sample size, which would lead to more reliable pooled results. However, further meta-analysis using other methods is warranted to confirm our results. The study had several limitations and thus, the results should be interpreted cautiously. First, significant study heterogeneity was present for several parameters, which decreased the robustness of the conclusions. Random-effect models and sensitivity analysis were used to reduce the impact of study heterogeneity on the meta-analysis results. Second, although 10 studies were included in the analysis, the number of patients was relatively small. A larger sample size is needed to obtain more reliable results. Third, the possibility of information and selection biases and unidentified confounders could not be completely excluded, as all included studies were observational. Fourth, although we searched several databases, other databases, such as Oncomine database, were not searched. Therefore, some relevant studies may have been missed, which may have undermined the robustness of the results. Fifth, CRC incidence greatly differs between Asian and Caucasian countries, but most patients included in our study were of Asian ethnicity, which may cause some selection bias. Finally, not much consensus exists on the evaluation of immunohistochemistry data. Thus, the pooled data in present study are subject to the bias caused by the various scoring systems used. Therefore, our results should be interpreted with caution. In conclusion, the results of our study demonstrate that loss of syndecan-1 expression correlates with histological grade and tumor stage, but not with lymph node metastasis or distant metastasis, in CRC. Furthermore, syndecan-1 expression does not have prognostic value in CRC patients.
Syndecan-1 and Angiogenic Cytokines in Multiple Myeloma: Correlation with Bone Marrow Angiogenesis and Survival
by Niels Frost Andersen; Therese Standal; Johan Lanng Nielsen; Lene Heickendorff; Magne Borset; Flemming Brandt Sorensen; Niels Abildgaard
British Journal of Haematology, 01/2005, Volume 128, Issue 2
Angiogenesis is a complex process involved in the proliferation and metastasis of malignant tumors, and partly triggered by the secretion of various angiogenic factors by tumor cells or cells in the stromal environment. We investigated the correlation between bone marrow angiogenesis, estimated as micro vessel density (MVD), and interleukin‐6 (IL‐6), basic fibroblastic growth factor (bFGF), hepatocyte growth factor (HGF) and syndecan‐1 in 67 patients with newly diagnosed multiple myeloma, and evaluated the prognostic value of these parameters. Circulating levels of IL‐6, bFGF, HGF and syndecan‐1 were significantly higher in patients than in controls. Moreover, in patients, bone marrow levels of bFGF, HGF and syndecan‐1 were higher than peripheral blood levels. Positive correlations were found between MVD and syndecan‐1 blood levels, syndecan‐1 bone marrow levels, and HGF blood levels. High MVD and high blood levels of IL‐6, HGF and syndecan‐1 were predictive of a shorter survival. In a multivariate survival analysis MVD and blood levels of IL‐6 retained independent prognostic significance, while in a survival analysis without MVD the peripheral blood levels of HGF and syndecan‐1 were strong independent prognostic factors.
Hyaluronan and Hyaluronan Synthases: Potential Therapeutic Targets in Cancer.
Adamia, Sophia; Maxwell, Christopher A.; Pilarski, Linda M.
Cardiovascular & Hematological Disorders, Volume 5, Number 1, 2005, pp. 3-14(12)
Current models of oncogenesis describe cancer as a progression of genetic mutations in a tumor cell mass. However, tumors are more than a clonal expansion of malignant cells. Tumors are heterogeneous, with a complex 3D structure, analogous to organs comprised of different tissues. In a tumor mass, the component cell types interact with each other and with their microenvironment by exchanging information through cell-cell interactions and / or through interactions with the extracellular matrix (ECM). These synergetic interactions facilitate tumor progression.
Furthermore, tumor invasion and metastatic development are accomplished through the breakdown of ECM. Disruption of ECM promotes abnormal inter- and / or intra- cellular signaling, leading to dysregulation of cell proliferation, growth and cytoskeleton reorganization. The disruption of the ECM in turn promotes the overproduction of growth factors, which induce elevated epithelial cell proliferation and other abnormalities including carcinogenesis. In this review we will demonstrate that hyaluronan (HA), a core component of ECM, contributes to certain types of cancer development. Additional to extracellular HA, intracellular and nuclear forms of HA have been detected. Intracellular HA is involved in cell signaling, whereas nuclear HA could promote chromatin condensation and thus facilitate mitosis. HA molecules are synthesized by hyaluronan synthases (HASs)-HAS1, HAS2 and HAS3 enzymes. Dysregulation of HAS genes results in abnormal production of HA and promotion of abnormal biological processes such as transformation and metastasis. The function of HASs appears to be cell and tissue specific. HAS1 maintains a low, basal level of HA. HAS2 is involved in embryonic and cardiac cushion morphogenesis and subsequent development through cell migration and invasion. HAS2 stimulates cell proliferation and angiogenesis. HAS3 appears to favor the malignant phenotype in many types of malignancies. However, the exact function of HAS isoenzymes and their role in cell signaling remains to be elucidated. A better understanding of HA and HASs may facilitate the design of novel therapeutic strategies to counter presumptive cancer-promoting effects of microenvironmental components.
Acute Ischemic Injury to the Renal Microvasculature in Human Kidney Transplantation
by Maarten G. Snoeijs; Hans Vink; Niek Voesten; Maarten H. Christiaans; Jan-Willem H. Daemen; Arnoud G. Peppelenbosch; Jan H. Tordoir; Carine J. Peutz-Kootstra; Wim A. Buurman; Geert Willem H. Schurink; L. W. Ernest van Heurn
Increased understanding of the pathophysiology of ischemic acute kidney injury in renal transplantation may lead to novel therapies that improve early graft function. Therefore, we studied the renal microcirculation in ischemically injured kidneys from donors after cardiac death (DCD) and in living donor kidneys with minimal ischemia. During transplant surgery, peritubular capillaries were visualized by side stream darkfield imaging. Despite a profound reduction in creatinine clearance, total renovascular resistance of DCD kidneys was similar to that of living donor kidneys. In contrast, renal microvascular perfusion in the early reperfusion period was 42% lower in DCD kidneys compared with living donor kidneys, which was accounted for by smaller blood vessel diameters in DCD kidneys. Furthermore, DCD kidneys were characterized by smaller red blood cell exclusion zones in peritubular capillaries and by greater production of syndecan-1 and heparan sulfate (main constituents of the endothelial glycocalyx) compared with living donor kidneys, providing strong evidence for glycocalyx degradation in these kidneys. We conclude that renal ischemia and reperfusion is associated with reduced capillary blood flow and loss of glycocalyx integrity. These findings form the basis for development of novel interventions to prevent ischemic acute kidney injury.
In conclusion, our study demonstrates that ischemically injured DCD kidneys are characterized by reduced microvascular blood flow and loss of glycocalyx integrity compared with a control group of intact kidneys from living donors. These findings may apply more generally to other conditions associated with ischemia and reperfusion injury such as acute myocardial infarction, stroke, and liver resection. Interventions aimed at increasing microvascular perfusion and restoring the endothelial glycocalyx may improve early graft function and enable expansion of the donor pool with kidneys that suffered prolonged ischemia.
Could Circulatory Syndecan-1 Be a Predictable Biomarker for Acute Kidney Injury in Patients with Acute Decompensated Heart Failure?
by Sueta, Daisuke; Hokimoto, Seiji
Circ. journal: official journal of the Japanese Circulation Society, 2015, Vol 79, Is 7
Syndecans are transmembrane proteoglycans (PGs) that consist of a core protein to which growth factor binding glycosaminoglycan side chains are attached.1 Syndecans affect a wide range of physiological processes, and their contribution is most apparent during wound repair.2 The Syndecan family, transmembrane heparan sulfate PGs, consists of 4 members: Syndecan-1 (Syndecan=the major syndecan of epithelial cells), Syndecan-2 (Fibroglycan=present primarily on cells of mesenchymal origin), Syndecan-3 (N-Syndecan= primarily observed in neuronal tissue and cartilage), and Syndecan-4 (Ryudocan/Amphyglycan=ubiquitously expressed)3,4
Finally, Neves et al provide clinically useful and important information for the risk stratification of ADHF patients who might develop AKI/WRF. The authors demonstrated that Syndecan-1 may be a potent useful biomarker in clinical situations, and their study cannot be highly evaluated until it has been published and read widely
Association of endothelial and glycocalyx injury biomarkers with fluid administration, development of acute kidney injury, and 90-day mortality: data from the FINNAKI observational study.
By Inkinen, Pettilä, Lakkisto, Kuitunen, Jukarainen, Bendel, Inkinen, Ala-Kokko, Vaara
Annals of Intensive Care. 2019 Sep;9(1):103. DOI: 10.1186/s13613-019-0575-y.
Injury to endothelium and glycocalyx predisposes to vascular leak, which may subsequently lead to increased fluid requirements and worse outcomes. In this post hoc study of the prospective multicenter observational Finnish Acute Kidney Injury (FINNAKI) cohort study conducted in 17 Finnish intensive care units, we studied the association of Syndecan-1 (SDC-1), Angiopoetin-2 (Ang-2), soluble thrombomodulin (sTM), vascular adhesion protein-1 (VAP-1) and interleukin-6 (IL-6) with fluid administration and balance among septic critical care patients and their association with development of acute kidney injury (AKI) and 90-day mortality. Patients who had high levels of all three markers, namely, SDC-1, Ang-2 and sTM, had an adjusted OR of 5.61 (95% CI 2.67-11.79; p < 0.001) for 90-day mortality. VAP-1 and IL-6 associated with fluid administration on the first ICU day. After adjusting for confounders, sTM was associated with development of AKI after 12 h from ICU admission. SDC-1, Ang-2 and sTM were independently associated with an increased risk for 90-day mortality.
Elevated Plasma Levels of PAI-1 Predict Cardiovascular Events and Cardiovascular Mortality in Prevalent Peritoneal Dialysis Patients
by Arikan, Hakki; Koc, Mehmet; Tuglular, Serhan; Ozener, Cetin; Akoglu, Emel
Renal Failure, 2009, Volume 31, Issue 6
Background. Elevated plasminogen activator inhibitor-1 (PAI-1) levels are associated with increased cardiovascular (CV) risk in the general population. It has been shown that peritoneal dialysis (PD) patients have increased plasma levels of PAI-1. The aim of this study was to investigate whether PAI-1 independently predicted CV outcome in PD patients. Material and Methods. Seventy-two PD patients (53% females, mean age 49.9 ± 16.1 years) were studied. Twelve patients who underwent kidney transplantation and 14 patients who transferred to hemodialysis during follow-up were excluded from the analysis. The remaining 46 patients (54% female, mean age 54 ± 16 years, dialytic age 42 ± 30 months) were followed a mean time of 45.4 ± 19.4 months (range 8-71 months). Baseline PAI-1, clinical, and laboratory parameters were assessed in all patients. Survival analyses were made with Kaplan-Meier and Cox regression analysis, with all-cause mortality and CV mortality and CV events (CVEs) as clinical end points. Results. During the follow-up, 29 patients died (17 from CV causes), and 28 fatal and non-fatal CVEs were recorded. The patients were divided according to plasma PAI-1 levels (i.e., ≤ or >41 ng/mL). The significant independent predictors of all-cause of mortality were age (60 years; p = 0.018), CRP (5 mg/L; p = 0.015), and serum albumin (<3.5 g/L; p = 0.011). Multivariable Cox regression analysis showed that plasma PAI-1 41 ng/mL was independently predictive of higher CV mortality (p = 0.021) and CVEs (p = 0.001). The only other independent predictor of CV mortality was only CRP (5 mg/L; p = 0.008). Conclusions. Plasma levels of PAI-1 41 ng/mL is a significant predictor of CV mortality and CVEs in PD patients. Results indicate that high plasma levels of PAI-1 (>41ng/mL) predicts cardiovascular events and cardiovascular mortality in patients with PD. This finding emphasizes that plasma PAI-1 levels should be taken into consideration when investigating CV risk in PD patients. The results also demonstrate further need for large-scale and well-designed studies in dialysis patients, aimed at elucidating the impact of PAI-1 on the development of cardiovascular disease.
Profound Endothelial Damage Predicts Impending Organ Failure and Death in Sepsis
by Johansen, Maria E; Johansson, Pär I; Ostrowski, Sisse R; Bestle, Morten H; Hein, Lars; Jensen, Anne; Søe-Jensen, Peter; Andersen, Mads; Steensen, Morten; Mohr, Thomas; Thormar, Katrin; Lundgren, Bettina; Cozzi-Lepri, Alessandro; Lundgren, Jens; Jensen, Jens-Ulrik
Seminars in Thrombosis and Hemostasis, 02/2015, Volume 41, Issue 1
Endothelial damage contributes to organ failure and mortality in sepsis, but the extent of the contribution remains poorly quantified. Here, we examine the association between biomarkers of superficial and profound endothelial damage (syndecan-1 and soluble thrombomodulin [sTM], respectively), organ failure, and death in sepsis. The data from a clinical trial, including critically ill patients predominantly suffering sepsis (Clinicaltrials.gov: NCT00271752) were studied. Syndecan-1 and sTM levels at the time of study enrollment were determined. The predictive ability of biomarker levels on death and organ failures during follow-up were assessed in Cox models adjusted for potential confounders including key organ dysfunction measures assessed at enrollment. Of the 1,103 included patients, 418 died. sTM levels at the time of enrollment independently predicted risk of death in adjusted models. Conversely, syndecan-1 levels failed to predict death. sTM but not syndecan-1 levels at enrollment predicted risk of multiple organ failure during follow-up. Profound damage to the endothelium independently predicts risk of multiple organ failure and death in septic patients. Our findings also suggest that the detrimental effect of profound endothelial damage on risk of death operates via mechanisms other than causing organ failures per se. Therefore, damage to the endothelium appears centrally involved in the pathogenesis of death in sepsis and could be a target for intervention.
Coagulopathy, catecholamines, and biomarkers of endothelial damage in experimental human endotoxemia and in patients with severe sepsis: A prospective study.
by Ostrowski, Sisse R., MD, PhD, DMSc; Berg, Ronan M.G., MD; Windeløv, Nis A., MD; Meyer, Martin A.S., BSc; Plovsing, Ronni R., MD; Møller, Kirsten, MD, PhD, DMSc; Johansson, Pär I., MD, DMSc, MPA
Journal of Critical Care, 2013, Volume 28, Issue 5
The aim of this study was to investigate associations between circulating catecholamines, endothelial damage, and coagulopathy in experimental human endotoxemia and septic patients. Endotoxemia increased heart rate, temperature, white blood cell count, C-reactive protein and procalcitonin, decreased blood pressure and induced a hemostatic response with platelet consumption, reduced protein C and sCD40L levels and enhanced tissue-type plasminogen activator release (all P<.05). Septic patients had increased levels of noradrenaline, syndecan-1, thrombomodulin, histone-complexed DNA and sCD40L but reduced soluble vascular endothelial cadherin and plasminogen activator inhibitor 1 (all P<.05) and plasma catecholamines correlated positively with syndecan-1 (adrenaline and noradrenaline) and sTM (only noradrenaline) (all P<.05), biomarkers reflecting endothelial damage. Furthermore, noradrenaline, syndecan-1 and thrombomodulin levels correlated with INR and disease severity scores (noradrenaline and thrombomodulin) (all P<.05).
Experimental endotoxemia induced a discrete hemostatic response without sympathoadrenal activation or endothelial damage. Septic patients had high levels of catecholamines and endothelial damage biomarkers that correlated with each other and with markers of hypocoagulability and disease severity.
Sepsis-Induced Degradation of Endothelial Glycocalyx
by Henrich, Michael; Gruss, Marco; Weigand, Markus A
The Scientific World Journal, 05/2010, Volume 10
Sepsis, a general inflammatory response to microbiological infection, is still a major cause of high mortality rates in intensive care units. This mortality rate strongly correlates with sepsis-induced impairment of organ blood supply as a consequence of disturbed capillary circulation and vascular leakage. Within this pathophysiological process, endothelial cell function plays a key role. Recent studies provide evidence that degradation of the glycocalyx on the luminal cell membrane is an early step in septic vascular endothelial cell disorder and its shed compounds, such syndecan-1, heparan sulfate, intercellular-adhesion-molecule-1 (ICAM-1), and vascular-cell-adhesion-molecule-1 (VCAM-1), can be quantified in the plasma. The plasma concentrations of heparan sulfate and syndecan-1 strongly correlate with severity of sepsis and with inflammatory markers such as interleukin-6 (IL-6). Furthermore, a nonspecific deterioration of the glycocalyx occurs during major abdominal surgery and during ischemia/reperfusion after vascular surgery. Both surgical treatments cause vascular leakage and, consequently, tissue edema, similar to that triggered by inflammatory impairment of the endothelial cell barrier. So far, no specific therapeutic strategies exist to maintain glycocalyx integrity; hence, conserving endothelial function. Detection of glycocalyx compounds in the plasma can be utilized as diagnostic markers to evaluate sepsis-induced endothelial damage and to estimate severity of sepsis. In the future, efforts will be made to prevent glycocalyx damage during sepsis or major surgery. As a result, this will possibly preserve organ function and improve patient outcome.
The glycocalyx is shed during inflammation and nonspecifically after surgery, explaining capillary leaking. Future studies should focus on how the glycocalyx is degraded in sepsis and after abdominal surgery. This understanding will be pivotal in order to develop therapeutic strategies to preserve the glycocalyx and, consequently, this will possibly reduce vascular leaking, with its fateful impact on organ functions, and improve the outcome of patients after abdominal surgery and sepsis.
The Role of the Endothelium in Severe Sepsis and Multiple Organ Dysfunction Syndrome
by Aird, William C
Blood, 05/2003, Volume 101, Issue 10
Sepsis is the most common cause of death among hospitalized patients in noncoronary intensive care units. Thus, an important goal in critical care medicine is to develop novel therapeutic strategies that will impact favorably on patient outcome. Unfortunately, the pathophysiology of severe sepsis remains poorly defined. While it is generally accepted that sepsis-associated mortality is related to the host response and involves a multitude of cell types, inflammatory mediators, and coagulation factors, clinical studies have largely failed to identify an effective therapeutic target. Future advances in sepsis therapy will require a better understanding of how the individual components of the host response interact. The endothelium plays a critical role in mediating the sepsis phenotype. This article provides an overview of sepsis and its complications, discusses the role of the endothelium in orchestrating the host response in sepsis, and emphasizes the potential value of the endothelium as a target for sepsis therapy.
Despite new information about the pathophysiology and treatment of severe sepsis, this disorder continues to be associated with an unacceptably high mortality rate. Future breakthroughs will require a conceptual shift that emphasizes relationships between the various mediators and cells involved in host response. The endothelium is key in initiating, perpetuating, and modulating the host response to infection. Additional studies promise to provide new insight into the endothelium, not as an isolated mechanism of sepsis pathophysiology, but rather as the coordinator of a far more expansive, spatially and temporally orchestrated response. A recent study demonstrated that activated protein C signals through PAR-1 in cultured endothelial cells, by an EPCR-dependent mechanism.291 Consistent with these results, both EPCR and PAR-1 were shown to be required for mediating the cytoprotective function of activated protein C in hypoxic cultured human brain endothelial cells and in a stroke model of mice.292 Collectively, these findings suggest that activated protein C signals through the PAR-1 receptor both in vitro and in vivo. Since PAR-1 is also a receptor for thrombin, these studies raise interesting questions as to how two distinct ligands, namely activated protein C and thrombin, mediate opposing PAR-1 responses (e.g., protective and proinflammatory responses, respectively).
The role oF the endothelium in severe sepsis and Association between biomarkers of endothelial injury and hypocoagulability in patients with severe sepsis: a prospective study
by Ostrowski, Sisse Rye; Haase, Nicolai; Müller, Rasmus Beier; Møller, Morten; Pott, Frank; Perner, Anders; Johansson, Pär
Critical care (London, England), 04/2015, Volume 19, Issue 1
Patients with severe sepsis often present with concurrent coagulopathy, microcirculatory failure and evidence of vascular endothelial activation and damage. Given the critical role of the endothelium in balancing hemostasis, this study investigated single-point associations between whole blood coagulopathy by thrombelastography (TEG) and plasma/serum markers of endothelial activation and damage in patients with severe sepsis. We found that a single time-point measurement of plasma markers of endothelial damage and, to a lesser degree, endothelial activation, were independently associated with whole blood hypocoagulability by TEG in patients with severe sepsis, and that fibrinolysis correlated inversely with markers of glycocalyx damage. These findings suggest that endothelial activation and damage may be linked to hypocoagulability in patients with severe sepsis.
A single time-point measurement of plasma markers of endothelial damage and, to a lesser degree, endothelial activation, were independently associated with whole blood hypocoagulability by TEG in patients with severe sepsis and septic shock.
Fibrinolysis was inversely associated with syndecan-1, a marker of glycocalyx damage.
These findings suggest that endothelial activation and damage may be linked to hypocoagulability in patients with severe sepsis.
Clinically, endothelial protective interventions would be expected to attenuate sepsis-induced hypocoagulability
Crit Care, 23(1):16, 16 Jan 2019
Clinical studies have demonstrated the correlation between blood levels of glycocalyx components with organ dysfunction, severity, and mortality in sepsis. Fluid resuscitation therapy is an essential part of sepsis treatment, but overaggressive fluid therapy practices (leading to hypervolemia) may augment glycocalyx degradation. Conversely, fresh frozen plasma and albumin administration may attenuate glycocalyx degradation. The beneficial and harmful effects of fluid and plasma infusion on glycocalyx integrity in sepsis are not well understood; future studies are warranted. In this review, we first analyze the underlying mechanisms of glycocalyx degradation in sepsis. Second, we demonstrate how the blood and urine levels of glycocalyx components are associated with patient outcomes. Third, we show beneficial and harmful effects of fluid therapy on the glycocalyx status during sepsis. Finally, we address the concept of glycocalyx degradation as a therapeutic target.
Glycocalyx degradation is gaining recognition as an important aspect of sepsis pathophysiology. Although the mechanisms of degradation are not fully elucidated, the increased plasma and urine levels of glycocalyx components may serve as diagnostic and prognostic biomarkers in sepsis. Some studies have investigated components that protect the glycocalyx from degradation, while others investigate the possibility of repair of a degraded glycocalyx. The relationship between the degradation and fluid therapy could yield other new insights into the prevention of the degradation. Finally, given the emerging role of the glycocalyx as a central part of sepsis pathophysiology, further studies are needed to establish therapeutic strategies to treat glycocalyx degradation in sepsis.