heparitin-sulfate and Vascular-Diseases

Topics: Abciximab; Animals; Anistreplase; Antibodies, Monoclonal; Anticoagulants; Aspirin; Chondroitin Sulfates; Clopidogrel; Dermatan Sulfate; Drug Combinations; Fibrinolytic Agents; Heparin, Low-Molecular-Weight; Heparitin Sulfate; Humans; Immunoglobulin Fab Fragments; Intermittent Claudication; Platelet Aggregation Inhibitors; Streptokinase; Ticlopidine; Vascular Diseases; Venous Thrombosis

The desire to describe biological data using mathematical models has led to the rapid development of various analytical techniques for model identification and parameter estimation. The procedures used may be non-linear and complex, and require long calculation periods. Thus, the aid of a personal computer renders efficient the application of these rather complicated procedures. In this study we developed a simple identification programme for heparan sulfate pharmacodynamics which can be easily and rapidly implemented on a personal computer. The programme is based on an iterative algorithm performing a non-linear regression analysis by the least-square method. This programme was applied to a clinical measured variables with which it was possible to quantify the pharmacodynamic effect of heparan sulfate.

Topics: Aged; Algorithms; Double-Blind Method; Female; Heparitin Sulfate; Humans; Least-Squares Analysis; Male; Microcomputers; Middle Aged; Plasminogen Inactivators; Serum Globulins; Software; Tissue Plasminogen Activator; Vascular Diseases

The endothelial cell-cell junction has emerged as a major cell signaling structure that responds to shear stress by eliciting the activation of signaling pathways. Platelet endothelial cell adhesion molecule-1 (PECAM-1) and heterotrimeric G protein subunits Gαq and 11 (Gαq/11) are junctional proteins that have been independently proposed as mechanosensors. Our previous findings suggest that they form a mechanosensitive junctional complex that discriminates between different flow profiles. The nature of the PECAM-1·Gαq/11 interaction is still unclear although it is likely an indirect association. Here, we investigated the role of heparan sulfates (HS) in mediating this interaction and in regulating downstream signaling in response to flow. Co-immunoprecipitation studies show that PECAM-1·Gαq/11 binding is dramatically decreased by competitive inhibition with heparin, pharmacological inhibition with the HS antagonist surfen, and enzymatic removal of HS chains with heparinase III treatment as well as by site-directed mutagenesis of basic residues within the extracellular domain of PECAM-1. Using an in situ proximity ligation assay, we show that endogenous PECAM-1·Gαq/11 interactions in endothelial cells are disrupted by both competitive inhibition and HS degradation. Furthermore, we identified the heparan sulfate proteoglycan syndecan-1 in complexes with PECAM-1 that are rapidly decreased in response to flow. Finally, we demonstrate that flow-induced Akt activation is attenuated in endothelial cells in which PECAM-1 was knocked down and reconstituted with a binding mutant. Taken together, our results indicate that the PECAM-1·Gαq/11 mechanosensitive complex contains an endogenous heparan sulfate proteoglycan with HS chains that is critical for junctional complex assembly and regulating the flow response.

Topics: Cell Communication; Cells, Cultured; Endothelial Cells; Gene Expression Regulation; GTP-Binding Protein alpha Subunits, Gq-G11; HEK293 Cells; Heparitin Sulfate; Humans; Mutation; Platelet Endothelial Cell Adhesion Molecule-1; Protein Binding; Protein Multimerization; Protein Structure, Tertiary; RNA, Small Interfering; Stress, Mechanical; Syndecan-1; Transfection; Vascular Diseases

The therapeutic use of VEGF165 to stimulate blood vessel formation for the treatment of peripheral arterial disease or cardiovascular-related disease has met with limited success. Here we describe an affinity-isolated heparan sulfate glycotherapeutic (HS7(+ve)) that binds to, and enhances the bioactivity of, VEGF165. Application of HS7(+ve) complexed with VEGF165 results in enhanced VEGF165-VEGFR2 interaction, prolonged downstream pErk1/2 signalling, and increased cell proliferation and tube formation in HUVECs, compared with VEGF165 alone. The pro-angiogenic potential of HS7(+ve) was further assessed in vivo using the chick embryo chorioallantoic membrane (CAM) assay. Exogenous dosing with HS7(+ve) alone significantly enhanced the formation of new blood vessels with potencies comparable to VEGF165. These results demonstrate the potential for vascular therapy of glycotherapeutic agents targeted at augmenting the bioactivity of VEGF165.

Topics: Angiogenesis Inducing Agents; Biosensing Techniques; Blood Vessels; Cell Proliferation; Heparitin Sulfate; Human Umbilical Vein Endothelial Cells; Humans; Protein Binding; Protein Engineering; Signal Transduction; Vascular Diseases; Vascular Endothelial Growth Factor A

Heparan sulfate proteoglycans play a pivotal role in tissue function, development, inflammation, and immunity. We have identified a novel cDNA encoding human heparanase, an enzyme thought to cleave heparan sulfate in physiology and disease, and have located the HEP gene on human chromosome 4q21. Monoclonal antibodies against human heparanase located the enzyme along invasive extravillous trophoblasts of human placenta and along endothelial cells in organ xenografts targeted by hyperacute rejection, both sites of heparan sulfate digestion. Heparanase deposition was evident in arterial walls in normal tissues; however, vascular heparan sulfate cleavage was coincident with heparanase enzyme during inflammatory episodes. These findings suggest that heparanase elaboration and control of catalytic activity may contribute to the development and pathogenesis of vascular disease and suggest that heparanase intervention might be a useful therapeutic target.

Topics: Amino Acid Sequence; Animals; Antibodies, Monoclonal; Cell Line; Chromosomes, Human, Pair 4; DNA, Complementary; Endothelium, Vascular; Gene Expression; Glucuronidase; Glycoside Hydrolases; Graft Rejection; Heparitin Sulfate; Humans; Inflammation; Molecular Sequence Data; Peptide Fragments; Swine; Trophoblasts; Vascular Diseases

In the very old, there is an increased prevalence of immunologically mediated vascular disease. Vascular heparan sulfate proteoglycan (vHSPG) is a molecule which plays an important structural and functional role in the vasculature. Autoimmunity to vHSPG may play a role in the pathogenesis of vascular disease. The presence of autoantibodies to vHSPG was investigated in sera from aged nursing home patients who have a high prevalence of vascular disease. The results showed an association of the presence of autoantibodies to vHSPG in the sera from patients in this aged population with vascular disease, particularly cerebrovascular disease, renal disease and diabetes. In addition, autoantibodies to vHSPG protein core were associated with cerebrovascular disease in this frail elderly population. These studies support the hypothesis that autoimmunity may play a role in vascular disease in the aged.

Topics: Aged; Aged, 80 and over; Autoantibodies; Autoimmunity; Blood Vessels; Enzyme-Linked Immunosorbent Assay; Female; Heparan Sulfate Proteoglycans; Heparitin Sulfate; Humans; Male; Mesylates; Proteoglycans; Vascular Diseases

We have previously demonstrated that platelets obtained from patients with anorexia nervosa or severe peripheral vascular disease are hyperaggregable. Since conventional heparins are known to activate platelets in vitro and occasionally induce thrombosis and consumptive thrombocytopenia in vivo, we have investigated the direct effect of a conventional heparin on platelets obtained from patients with anorexia nervosa or severe peripheral vascular disease. Heparin at therapeutic concentrations was found to induce platelet aggregation of such platelets in vitro. In contrast, a recently developed low molecular weight heparinoid (Org 10172), at therapeutic concentrations, had no effect on these hyperaggregable platelets. We conclude that: heparin may be potentially harmful to patients with hyperaggregable platelets; thrombocytopenia and thrombosis associated with heparin therapy may be mediated through a direct effect of heparin on platelets; it is unlikely that heparin induced thrombocytopenia is always mediated by classical immunological mechanisms, especially in patients with hyperaggregable platelets; and low molecular weight heparinoids may be safer anticoagulants in patients with platelet hyperaggregability.

Topics: Adolescent; Adult; Aged; Anorexia Nervosa; Blood Platelets; Chondroitin Sulfates; Collagen; Dermatan Sulfate; Epinephrine; Female; Glycosaminoglycans; Heparin; Heparitin Sulfate; Humans; Immunoglobulin G; In Vitro Techniques; Male; Middle Aged; Platelet Aggregation; Thrombocytopenia; Thromboembolism; Thromboxane B2; Vascular Diseases