Physical and enzymatic perturbation of the architecture of the Tunica media destroys its inherent thromboresistance.
The media layer of the arterial cryo-cross sections, is defective for vWf-dependent platelet adhesion. Exposure of the same layer by stripping off the most inner portions of the vessel wall results in a highly thrombogenic surface. Stripping or balloon dilation was applied to porcine arteries prior to functional assays. Cryosections of treated or untreated arteries were perfused with porcine blood at 3,350 s(-1) and platelet deposition was detected by indirect immunofluorescence. Following balloon dilation, vWf-dependent platelet deposition increased; covering 9.08 +/- 1.36% of the total media surface area, this value for untreated vessels was 0.88 +/- 0.14%. A 10-fold increase was also found in the binding of vWf-coated fluorescent beads to the media. In addition to mechanical procedures, treatment by serine-proteases like trypsin, chymotrypsin and proteinase 3, or by chondroitinase ABC, but not by heparitinase also resulted in a 7-10-fold increase in platelet coverage over the media. Collagen in the media may be complexed with another vessel wall component shielding the vWf-binding sites. Mechanical or biochemical processes unmask these sites, and increase the thrombogenicity of the vessel wall.
Komorowicz
Erzsebet
E
Department of Medical Biochemsitry, Semmelweis University, Budapest, Hungary.
McBane
Robert D
RD
Fass
David N
DN
D000818:Animals; D001158:Arteries / Q000473:pathology; D001665:Binding Sites; D002404:Catheterization / Q000009:adverse effects; D008856:Microscopy, Fluorescence; D010973:Platelet Adhesiveness; D012697:Serine Endopeptidases / Q000378:metabolism; D013552:Swine; D013927:Thrombosis / Q000209:etiology* / Q000473:pathology; D017540:Tunica Media / Q000473:pathology* / Q000502:physiology; D014841:von Willebrand Factor / Q000378:metabolism
D014841:von Willebrand Factor; D012697:Serine Endopeptidases