Intense exercise increases shear-induced platelet aggregation in men through enhancement of von Willbrand factor binding, glycoprotein IIb/IIIa activation, and P-selectin expression on platelets
- 397 Downloads
Vigorous exercise transiently enhances the risk of primary cardiac arrest. Shear-induced platelet aggregation (SIPA) is an important mechanism in arterial thrombogenesis. This study investigates whether intense exercise affects SIPA, and elucidates mechanisms that underlie SIPA. Eighteen sedentary healthy men engaged in intense exercise (about 80% of maximal oxygen consumption) for 40 min on a bicycle ergometer. Platelet aggregation, binding of von Willebrand factor (vWF) to platelets, and activation of glycoprotein (GP) IIb/IIIa and expression of P-selectin on platelets induced by shear stress were analyzed both before and immediately after exercise. Analytical results demonstrated that: (1) the levels of plasma vWF antigen and activity were enhanced after intense exercise, (2) intense exercise increased either shear- or ristocetin-induced platelet aggregation and was accompanied by an increase in vWF binding to platelets and vWF-mediated GP IIb/IIIa activation at high shear flow, and (3) shear-induced P-selectin expression in the absence or the presence of exogenous vWF was enhanced by intense exercise. Therefore, we conclude that intense exercise promotes the extent of SIPA, possibly by enhancing the ability of vWF to bind to platelets and the subsequent activation of GP IIb/IIIa complexes, as well as the expression of P-selectin in response to shear stress, which in turn may augment the risk of vascular thrombosis.
KeywordsExercise Shear-induced platelet aggregation von Willebrand factor Adhesion molecules
The study was supported by the National Science Council Grant NSC 90-2320-B-182-006. The authors would like to thank the volunteers for their enthusiastic participation in this study.
- Scherer D, Kaltenbach M (1979) Frequency of lift-threatening complications associated with exercise testing. Dtsch Med Wochenschr 33:1161–1165Google Scholar
- Tozzi-Ciancarelli MG, Penco M, Di Massimo C (2002) Influence of acute exercise on human platelet responsiveness: possible involvement of exercise-induced oxidative stress. Eur J Appl Physiol 86:266–272Google Scholar
- Wang JS, Jen CJ, Chen HI (1995) Effects of exercise training and deconditioning on platelet function in men. Arterioscler Thromb Vasc Biol 15:1668–1674Google Scholar
- Wang JS, Jen CJ, Chen HI (1997a) Effects of chronic exercise and deconditioning on platelet function in women. J Appl Physiol 83:2080–2085Google Scholar