Chondroitin sulfate anticoagulant activity is linked to water transfer: relevance to proteoglycan structure in atherosclerosis

[Influence of chronic pain in osteoarthritis on the risk of cardiovascular diseases and modern methods of drug prevention]

The purpose of the review of scientific medical literature was to evaluate the data of the epidemiology of osteoarthritis (OA) and cardiovascular diseases (CVD) with the analysis of risk factors, pathophysiological and pathobiochemical mechanisms of the relationship between OA and the risk of developing CVD in the presence of chronic pain, modern strategies for screening and management of this cohort of patients, the mechanism of action and pharmacological effects of chondroitin sulfate (CS). Conclusions were drawn about the need for additional clinical and observational studies of the efficacy and safety of the parenteral form of CS (Chondroguard) in patients with chronic pain in OA and CVD, improvement of clinical recommendations for the treatment of chronic pain in patients with OA and cardiovascular risk, with special attention to interventions that eliminate mobility restrictions in patients and the inclusion of basic and adjuvant therapy with DMOADs to achieve the goals of multipurpose monotherapy in patients with contraindications to standard therapy drugs.

Recent advance in delivery system and tissue engineering applications of chondroitin sulfate

Chondroitin sulfate (CS) is a naturally derived bioactive macromolecule and the major component of extracellular matrix (ECM), which widely distributed in various organisms and has attracted much attention due to their significant bioactivities. It is regarded as a favorable biomaterial that has been applied extensively in field of drug delivery and tissue engineering due to its property of non-poisonous, biodegradation, biocompatible and as a major component of ECM. The present article reviews the structure and bioactivities of CS, from the preparation to structure analysis, and emphatically focuses on the biomaterial exertion in delivery system and tissue engineering. At the same time, the present application status and prospect of CS are analyzed and the biomaterial exertion of CS in delivery system and various tissue engineering are also comparatively discussed in view of biomaterial development.

A role for proteoglycans in vascular disease

The content of proteoglycans (PGs) is low in the extracellular matrix (ECM) of vascular tissue, but increases dramatically in all phases of vascular disease. Early studies demonstrated that glycosaminoglycans (GAGs) including chondroitin sulfate (CS), dermatan sulfate (DS), keratan sulfate (KS) and heparan sulfate (HS) accumulate in vascular lesions in both humans and in animal models in areas of the vasculature that are susceptible to disease initiation (such as at branch points) and are frequently coincident with lipid deposits. Later studies showed the GAGs were covalently attached to specific types of core proteins that accumulate in vascular lesions. These molecules include versican (CSPG), biglycan and decorin (DS/CSPGs), lumican and fibromodulin (KSPGs) and perlecan (HSPG), although other types of PGs are present, but in lesser quantities. While the overall molecular design of these macromolecules is similar, there is tremendous structural diversity among the different PG families creating multiple forms that have selective roles in critical events that form the basis of vascular disease. PGs interact with a variety of different molecules involved in disease pathogenesis. For example, PGs bind and trap serum components that accumulate in vascular lesions such as lipoproteins, amyloid, calcium, and clotting factors. PGs interact with other ECM components and regulate, in part, ECM assembly and turnover. PGs interact with cells within the lesion and alter the phenotypes of both resident cells and cells that invade the lesion from the circulation. A number of therapeutic strategies have been developed to target specific PGs involved in key pathways that promote vascular disease. This review will provide a historical perspective of this field of research and then highlight some of the evidence that defines the involvement of PGs and their roles in the pathogenesis of vascular disease.

Chondroitin sulfate interacts mainly with headgroups in phospholipid monolayers

Sulfated glycosaminoglycans are precursors of the extracellular matrix used to treat diseases related to blood clotting and degenerative joint diseases. These medical applications have been well established, but the mode of action at the molecular level, which depends on the interaction with cell membranes, is not known in detail. In this study, we investigated the interaction between chondroitin sulfate (CS) and phospholipid monolayers that mimic cell membranes. From surface pressure isotherms and polarization-modulated infrared reflection absorption spectroscopy (PM-IRRAS), CS was found to interact mainly with the polar groups of dipalmitoyl phosphatidylcholine (DPPC) and dipalmitoyl phosphatidylglycerol (DPPG), with negligible penetration into the hydrophobic tails and only small changes in monolayer elasticity for the packing corresponding to a real cell membrane. The changes in surface pressure and surface potential isotherms depended on CS concentration and on the time allowed for its adsorption onto the monolayer, which points to a dynamic adsorption-desorption process. The charge of the phospholipid was also relevant, since CS induced order into DPPC monolayers while the opposite occurred for DPPG, according to the PM-IRRAS spectra. In summary, interaction with polar groups is responsible for the CS effects on model cell membranes.

[Endothelial glycocalyx of blood circulation. II. Biological functions, state at norm and pathology, bioengineering application]

In normal state, a complex multicomponent system called glycocalyx is present on the surface of endothelial vascular system. Due to complexity of its composition and location on the border between vessel wall and blood circulation, glycocalyx participates in a number of functions supporting the metabolism of the vascular wall. In pathological conditions undergo complete or partial loss of this structure, which leads to inconsistencies in the vascular wall and change its functions. The functions of endothelial glycocalyx are its involvement in the regulation of vascular permeability, transduction and transformation by the shear stress of blood flow on endothelium, the molecular regulation of glycocalyx microenvironment and its interaction with circulating blood cells. Also briefly be considered participation of glycocalyx in the implementation of cardiovascular diseases, their correction, bioengineering application of glycocalyx and its components.

Inhibition of antithrombin by Plasmodium falciparum histidine-rich protein II

Histidine-rich protein II (HRPII) is an abundant protein released into the bloodstream by Plasmodium falciparum, the parasite that causes the most severe form of human malaria. Here, we report that HRPII binds tightly and selectively to coagulation-active glycosaminoglycans (dermatan sulfate, heparan sulfate, and heparin) and inhibits antithrombin (AT). In purified systems, recombinant HRPII neutralized the heparin-catalyzed inhibition of factor Xa and thrombin by AT in a Zn(2+)-dependent manner. The observed 50% inhibitory concentration (IC(50)) for the HRPII neutralization of AT activity is approximately 30nM for factor Xa inhibition and 90nM for thrombin inhibition. Zn(2+) was required for these reactions with a distribution coefficient (K(d)) of approximately 7μM. Substituting Zn(2+) with Cu(2+), but not with Ca(2+), Mg(2+), or Fe(2+), maintained the HRPII effect. HRPII attenuated the prolongation in plasma clotting time induced by heparin, suggesting that HRPII inhibits AT activity by preventing its stimulation by heparin. In the microvasculature, where erythrocytes infected with P falciparum are sequestered, high levels of released HRPII may bind cellular glycosaminoglycans, prevent their interaction with AT, and thereby contribute to the procoagulant state associated with P falciparum infection.

A versatile pH sensitive chondroitin sulfate-PEG tissue adhesive and hydrogel

We developed a chondroitin sulfate-polyethylene glycol (CS-PEG) adhesive hydrogel with numerous potential biomedical applications. The carboxyl groups on chondroitin sulfate (CS) chains were functionalized with N-hydroxysuccinimide (NHS) to yield chondroitin sulfate succinimidyl succinate (CS-NHS). Following purification, the CS-NHS molecule can react with primary amines to form amide bonds. Hence, using six arm polyethylene glycol amine PEG-(NH2)6 as a crosslinker we formed a hydrogel which was covalently bound to proteins in tissue via amide bonds. By varying the initial pH of the precursor solutions, the hydrogel stiffness, swelling properties, and kinetics of gelation could be controlled. The sealing/adhesive strength could also be modified by varying the damping and storage modulus properties of the material. The adhesive strength of the material with cartilage tissue was shown to be ten times higher than that of fibrin glue. Cells encapsulated or in direct contact with the material remained viable and metabolically active. Furthermore, CS-PEG material produced minimal inflammatory response when implanted subcutaneously in a rat model and enzymatic degradation was demonstrated in vitro. This work establishes an adhesive hydrogel derived from biological and synthetic components with potential application in wound healing and regenerative medicine.

Heparin-like effect in liver disease and liver transplantation

Liver cirrhosis is characterized by impairment of primary and secondary hemostasis but it is not clear how this impairment is related to the bleeding problems seen in cirrhosis. This delicate hemostatic balance can be perturbed by numerous conditions, such as variceal bleeding, renal failure, or infection/sepsis, which may lead to worsening of coagulation status to date. The role of endogenous heparinoids (glycosaminoglycans) in the coagulopathy of patients who have cirrhosis has been demonstrated by thromboelastography with the addition of heparinase I in patients who have recent variceal bleeding and infection. The heparin-like effect has also been demonstrated to be part of the coagulopathy seen after reperfusion in patients who have cirrhosis and are undergoing liver transplant. Therapeutic implications of these findings are not clear at the moment and the use of drugs able to cleave heparinoids should be explored.

Characterization of total plasma glycosaminoglycan levels in healthy volunteers following oral administration of a novel antithrombotic odiparcil with aspirin or enoxaparin

Odiparcil is a novel, orally active beta-d-thioxyloside analog with antithrombotic activity associated with a reduced risk of adverse bleeding events. Its unique mechanism of action is postulated by means of an elevation in circulating endogenous chondroitin sulfate-related glycosaminoglycans (GAGs) levels. The purpose of these 2 separate clinical studies was to evaluate plasma GAG levels in healthy subjects administered odiparcil with either aspirin (ASA) or enoxaparin. Clinical plasma samples were processed and analyzed using validated HPLC bioassays that indirectly estimate GAG levels based on the simultaneous detection of the chondroitin disaccharide derivatives. The concomitant administration of odiparcil with or without ASA resulted in a significant elevation in GAG levels over baseline for both treatment groups. In the other clinical study, the concomitant administration of odiparcil with or without enoxaparin displayed significant increases in plasma DeltaDi-OS, DeltaDi-4S, and total disaccharide levels versus control group. Neither plasma GAG levels nor odiparcil plasma levels were correlated with a rise in hepatic transaminases, an adverse drug event observed in several subjects; and plasma odiparcil levels were indirectly correlated with plasma GAG levels. These clinical studies were proof of concept of preclinical rat studies indicating that chronic odiparcil treatment elevates endogenous GAG levels in human subjects.

Versican in health and disease

Versican is a component of the extracellular matrix, which interacts with several matrix and cell surface molecules. Versican plays central roles in tissue morphogenesis and homeostasis and is implicated in the development of numerous diseases. The expression of versican by multiple cell types is differentially regulated in a temporal and spatial manner in physiological and pathological processes. It participates in various biological events such as tissue organization, cell proliferation, adhesion, migration, and angiogenesis. The physiology of versican and its role in the progression of diseases such as atherosclerosis, cancer, and central nervous system injury are discussed.

The effects of glycosaminoglycans on coagulation: a thromboelastographic study

Endogenous heparinoids impair coagulation, evidenced by thrombelastography in cirrhotic patients with bacterial infection, but it is not clear which glycosaminoglycans can be detected by native and heparinase-modified thrombelastography. To assess the effects of different glycosaminoglycans on thrombelastography parameters and the reversibility of these effects by heparinase-I-modified thrombelastography. Twenty volunteers were enrolled. Solutions of heparan sulphate, dermatan sulphate, and chondroitin-4-sulphate were prepared at 'equivalent' concentrations, based on the composition and anticoagulant activity of danaparoid. Serial dilutions of each glycosaminoglycan were prepared to achieve 1.0, 0.5, 0.1, and 0.05 U/ml. Native and heparinase-modified thrombelastography, anti-activated factor X activity and heparin cofactor II activity were evaluated at each concentration. A statistically significant heparin-like effect was seen with 1 and 0.5 U/ml heparan sulphate, and 1 and 0.5 U/ml dermatan sulphate, which was completely reversed by heparinase-modified thrombelastography. Anti-activated factor X activity was significantly increased in samples containing heparan and dermatan sulphates. The heparin cofactor II activity decreased with 1.0 and 0.5 U/ml dermatan sulphate and chondroitin-4-sulphate, but not with heparan sulphate. Heparan and dermatan sulphates affect haemostasis when added to whole blood in vitro, detectable by native thrombelastography and completely reversed by heparinase-I-modified thrombelastography. They may therefore be responsible for the heparin-like effect seen by thrombelastography in patients with cirrhosis and bacterial infection.

Interleukin-1β selectively decreases the synthesis of versican by arterial smooth muscle cells

Proteoglycans accumulate in lesions of atherosclerosis but little is known as to which factors regulate the synthesis of these molecules. Interleukin-1beta (IL-1beta) is a cytokine involved in vascular lesion development but it is not clear whether it has specific effects on proteoglycan synthesis by arterial smooth muscle cells (ASMC). Monkey ASMC were treated with IL-1beta and proteoglycan synthesis assessed using [(35)S]-sulfate and [(35)S]-Trans amino acid labeling. Four prominent size populations of proteoglycans, as determined by SDS-PAGE gradient gel electrophoresis, were observed in the culture medium and identified as versican, biglycan, decorin, and an unknown population that migrated to the gel interface. IL-1beta treatment decreased significantly the synthesis of versican, while increasing the synthesis of decorin, but having no effect on biglycan synthesis. Northern blot analyses confirmed this selective effect on versican and decorin mRNA transcripts. Nuclear run-on and RNA inhibition studies showed that decreased mRNA for versican was due to increased mRNA degradation and not to changes in transcription. In addition, IL-1beta increased the synthesis of the population of proteoglycans that separated at the SDS-PAGE gel interface. Chondroitinase ABC lyase digestion of this population revealed a complex of proteins composed of versican (350 kDa), an unidentified protein (215 kDa), and a 23 kDa protein identified by sequence analyses as serglycin. These data demonstrate that IL-1beta selectively downregulates versican synthesis by ASMC, while positively regulating the synthesis of other proteoglycans.

Versican degradation and vascular disease

Versican is an abundant proteoglycan in the blood vessel wall that is increased after vascular injury and accumulates in advanced atherosclerotic plaques. Versican is a large molecule with domains that mediate binding to cytokines, enzymes, lipoproteins, other extracellular matrix molecules, and signaling receptors. There is evidence that versican exists in the normal, as well as the diseased, vessel wall as discrete fragments, which represent these functional domains. We review the literature on versican degradation in vascular tissue and the function of versican domains, all of which suggest that proteolytic modification of versican may have physiologic as well as pathologic implications for the vascular system.

Versican G3 domain promotes blood coagulation through suppressing the activity of tissue factor pathway inhibitor-1

We have detected versican, a member of the large chondroitin sulfate proteoglycans, and its degraded C-terminal G3 fragments in human plasma and observed that the versican G3 domain promoted blood coagulation. Silencing G3 expression with small interfering RNA reduced the effect of G3 on coagulation. Plasma coagulation assays suggest that G3 enhances coagulation irrespective of its actions on platelets and white blood cells. To examine how versican affected blood coagulation, we used normal human plasma and different types of coagulation factor-deficient plasmas. The experiments indicated that versican enhanced coagulation through the extrinsic pathway, and that Factor VII was the target molecule. FVII activity assays showed that G3 activated FVII in the presence of plasma but not with purified FVII directly. Yeast two-hybrid, immunoprecipitation, and gel co-migration assays showed that G3 interacted with the tissue factor pathway inhibitor-1 (TFPI-1). TFPI-1 activity assays suggested that G3 inhibited TFPI-1 activity, allowing FVIIa and FXa to facilitate the coagulation process. G3-induced blood coagulation was further confirmed with a mouse model in a real-time manner. Taken together, these results indicate that versican may represent a new target for the development of therapies against atherosclerosis.

Osmotic stress regulates the anticoagulant efficiency of dermatan sulfate

Glycosaminoglycans (GAGs) in pericellular and interstitial spaces help to maintain local water homeostasis and blood coagulation balance. This study explored whether dehydrating microenvironment conditions influence dermatan sulfate's (DS) anticoagulant activity. Water transfer during antithrombin activation by dermatan sulfate was measured using osmotic stress techniques. Anticoagulant activity was determined from the change in the rate of coagulation factor Xa (fXa) inhibition. Osmotic stress accelerated reaction rates, indicating water transfer from reactants to bulk. The net volume transferred, measured using osmotic probes similar in size to the reacting proteins, was approximately 2500 mol of water per mole of fXa inhibited. The reaction efficiency, V(sat)/K 1/2 (rate at saturation/concentration resulting in half-maximal rates), determined in titrations with monosulfated dermatan sulfate and disulfated dermatan sulfate (DDS), were 4x10(4) and 2x10(5) M-1 s-1 under osmotic stress and in the presence of calcium, corresponding to 34- and 81-fold increases over efficiency measured under standard conditions. These results indicate that dermatan sulfate can contribute significantly to antithrombin activation, and that in dehydrating environments and depending of ionic conditions, its anticoagulant efficiency can exceed that of heparan sulfate (HS).

Molecular dissection of Na+ binding to thrombin

Na(+) binding near the primary specificity pocket of thrombin promotes the procoagulant, prothrombotic, and signaling functions of the enzyme. The effect is mediated allosterically by a communication between the Na(+) site and regions involved in substrate recognition. Using a panel of 78 Ala mutants of thrombin, we have mapped the allosteric core of residues that are energetically linked to Na(+) binding. These residues are Asp-189, Glu-217, Asp-222, and Tyr-225, all in close proximity to the bound Na(+). Among these residues, Asp-189 shares with Asp-221 the important function of transducing Na(+) binding into enhanced catalytic activity. None of the residues of exosite I, exosite II, or the 60-loop plays a significant role in Na(+) binding and allosteric transduction. X-ray crystal structures of the Na(+)-free (slow) and Na(+)-bound (fast) forms of thrombin, free or bound to the active site inhibitor H-d-Phe-Pro-Arg-chloromethyl-ketone, document the conformational changes induced by Na(+) binding. The slow --> fast transition results in formation of the Arg-187:Asp-222 ion pair, optimal orientation of Asp-189 and Ser-195 for substrate binding, and a significant shift of the side chain of Glu-192 linked to a rearrangement of the network of water molecules that connect the bound Na(+) to Ser-195 in the active site. The changes in the water network and the allosteric core explain the thermodynamic signatures linked to Na(+) binding and the mechanism of thrombin activation by Na(+). The role of the water network uncovered in this study establishes a new paradigm for the allosteric regulation of thrombin and other Na(+)-activated enzymes involved in blood coagulation and the immune response.

Proteoglycans in Atherosclerosis and Restenosis

The proteoglycan versican is one of several extracellular matrix (ECM) molecules that accumulate in lesions of atherosclerosis and restenosis. Its unique structural features create a highly interactive molecule that binds growth factors, enzymes, lipoproteins, and a variety of other ECM components to influence fundamental events involved in vascular disease. Versican is one of the principal genes that is upregulated after vascular injury and is a prominent component in stented and nonstented restenotic lesions. The synthesis of versican is highly regulated by specific growth factors and cytokines and the principal source of versican is the smooth muscle cell. Versican interacts with hyaluronan, a long chain glycosaminoglycan, to create expanded viscoelastic pericellular matrices that are required for arterial smooth muscle cell (ASMC) proliferation and migration. Versican is also prominent in advanced lesions of atherosclerosis, at the borders of lipid-filled necrotic cores as well as at the plaque-thrombus interface, suggesting roles in lipid accumulation, inflammation, and thrombosis. Versican influences the assembly of ECM and controls elastic fiber fibrillogenesis, which is of fundamental importance in ECM remodeling during vascular disease. Collectively, these studies highlight the critical importance of this specific ECM component in atherosclerosis and restenosis.