title: Coimmobilized native macromolecular heparin proteoglycans strongly inhibit platelet-collagen interactions in flowing blood.
abstract: We coimmobilized mast cell-derived heparin proteoglycans (HEP-PGs) of very high molecular weight (750 kDa) or unfractionated heparin (UFH) on coverslips together with collagen without altering the amount of immobilized collagen. Subsequently, platelet-collagen interactions were studied under both flowing and static conditions in D-phenylalanyl-L-prolyl-L-arginine chloromethyl ketone-anticoagulated blood and platelet-rich plasma (PRP), respectively. At a high shear rate (1600 1/s), the mean platelet deposition (PD) on collagen monomers was 7.5+/-6.1x10(6)/cm(2) (n=5). When the monomers were coimmobilized with UFH, PD was inhibited by 73% (2.0+/-1.2x10(6)/cm(2)), whereas HEP-PG completely blocked it (0. 42+/-0.38x10(6)/cm(2); P<0.05). Also, when collagen fibrils were used for coating, HEP-PG significantly inhibited PD. At a low shear rate (200 1/s) and under static conditions in PRP, the inhibitory effect of HEP-PG on PD was less marked. Inhibition of glycoprotein IIb/IIIa did not affect PD on coimmobilized HEP-PG in contrast to coimmobilized UFH or collagen alone. As a sign of inactivation, platelets adhering to the HEP-PG surface released considerably less beta-thromboglobulin than did those adhering to pure collagen. In summary, immobilized HEP-PG strongly inhibited PD on collagen by attenuating adhesion-induced platelet activation. The stronger effect on collagen monomers suggests the inhibition of glycoprotein Ia/IIa-mediated activation.
authors.affiliation: Wihuri Research Institute, Helsinki, Finland.
authors.forename: P
authors.initials: P
authors.lastname: Kauhanen
authors.forename: P T
authors.initials: PT
authors.lastname: Kovanen
authors.forename: R
authors.initials: R
authors.lastname: Lassila
mesh_terms: D000818:Animals; D001783:Blood Flow Velocity; D001792:Blood Platelets / Q000737:chemistry / Q000378:metabolism*; D003094:Collagen / Q000037:antagonists & inhibitors* / Q000097:blood*; D006025:Glycosaminoglycans / Q000097:blood; D019812:Heparan Sulfate Proteoglycans / Q000097:blood* / Q000302:isolation & purification / Q000502:physiology*; D006493:Heparin / Q000097:blood / Q000494:pharmacology; D006801:Humans; D046911:Macromolecular Substances; D008407:Mast Cells / Q000737:chemistry; D010477:Perfusion; D010975:Platelet Aggregation Inhibitors / Q000097:blood / Q000494:pharmacology*; D051381:Rats; D001620:beta-Thromboglobulin / Q000378:metabolism; D014841:von Willebrand Factor / Q000378:metabolism
chemical_list: D006025:Glycosaminoglycans; D019812:Heparan Sulfate Proteoglycans; D046911:Macromolecular Substances; D010975:Platelet Aggregation Inhibitors; D001620:beta-Thromboglobulin; D014841:von Willebrand Factor; D006493:Heparin; D003094:Collagen