Effects of heparin and aspirin on circulating P-selectin, E-selectin and von Willebrand Factor levels in healthy men

As thrombin stimulates P-selectin expression on platelets and its release i nto plasma, we hypothesized that enhancing antithrombin activity by unfract ionated heparin (UFH) could decrease plasma levels of circulating (c)P-sele ctin, (c)E-selectin, and von Willebrand Factor (vWF). Hence the effect of U FH and aspirin were examined on these activation markers in healthy volunte ers. UFH decreased cP-selectin levels by - 10% (CI: - 16--4%; P = 0.005) at 24 h, but did not change levels of vWF-Ag. In contrast, aspirin did not af fect cP-selectin levels but decreased vWF-Ag levels by - 12% (CI: - 18- -7% ; P = 0.005) at 24 h. Neither drug affected cE-selectin levels. Thus, UFH d ecreases cP-selectin levels, which may reflect decreased platelet activatio n in vivo. An increase in cP-selectin under UFH therapy should alert the cl inician to look Fur platelet destruction. (C) 2001 Elsevier Science Ireland Ltd. All rights reserved.