A human model for study of blood-vascular wall interactions. Effects of enzymatic treatment of intima.

A human umbilical cord vein model was used to study the interaction of human blood with vein intima after treatment with certain enzymes. Treatment of the intima with neuraminidase produced little in the way of morphologic change, and studies showed no increase in the retention of platelets labeled with chromium 51. Treatment of vein intima with collagenase produced severe morphologic changes, with exposure of coarse and fine subendothelial fibers, but with the retention of platelets little enhanced, as determined morphologically or radiometrically. On the other hand, treatment of vein intima with trypsin resulted in loss of endothelium in some areas, with exposure of coarse subendothelial fibers that produced a marked increase in platelet retention, as determined both morphologically and radiometrically. Exposure of the vein intima to thrombin produced apparent contraction of endothelial cells, with focal exposure of subendothelium and platelet adhesion.