REDUCTION OF PLATELET-ADHESIVENESS BY VITAMIN-E SUPPLEMENTATION IN HUMANS

Platelet adhesion was tested ex vivo in a group of 7 normal individuals on varying doses of vitamin E. Adhesion to glass slides coated with fibrinogen, fibronectin, collagen I and collagen V was studied by perfusing platelet-rich plasma through a flow chamber. Time- and space-resolved observations of platelet adhesion were made in an area of parallel flow lines and low shear rate under standardized conditions before and after dietary supplementation with vitamin E. The doses varied from 400 I.U./day to 1600 I.U./day 400 I.U. increments. A statistically significant reduction in platelet adhesion was noted on all four adhesive surfaces at the 400 I.U. level of vitamin E supplementation. This reduction varied in magnitude depending on the adhesive surface. As vitamin E supplementation was increased, no dose-dependent downward trend in adhesion rate was observed although the platelet alpha-tocopherol content progressively increased. Based on our results, we suggest that 400 I.U./day may be a near optimal dose of vitamin E to reduce platelet adhesivity as evaluated in our flow chamber system.