Ascorbic Acid Infusion Blunts CD40L Upregulation in Patients Undergoing Coronary Stent

Objectives: To reduce the increase of oxidative stress and the upregulation of CD40L during stenting procedure using ascorbic acid infusion. Background: CD40L upregulation occurring after coronary Percutaneous Coronary Intervention predicts vascular events but the underlying mechanism is still unclear. Methods: Fifty-six patients undergoing elective coronary stenting were randomly allocated to intravenous infusion of the antioxidant ascorbic acid or placebo. Platelet CD40L and plasma levels of soluble CD40L and of 8-hydroxy-2'-deoxyguanosine, a marker of oxidative stress, were measured before and after coronary stenting. In vitro study was also done to measure reactive oxidant species and CD40L expression in platelets exposed to anoxia-reoxygenation. Results: Placebo-treated patients showed a significant increase of platelet CD40L, soluble CD40L and 8-hydroxy-2'-deoxyguanosine compared to baseline values. Patients given ascorbic acid showed no change of soluble CD40L and platelet CD40L but a significant decrease of 8-hydroxy-2'-deoxyguanosine. After 60 and 120 min, soluble CD40L, platelet CD40L and 8-hydroxy-2'-deoxyguanosine were significantly lower in the ascorbic acid-treated group compared to the placebo-treated one. A significant correlation between platelet CD40L and soluble CD40L and between soluble CD40L and 8-hydroxy-2'-deoxyguanosine was observed. Platelets, in vitro exposed to anoxia-reoxygenation, had a burst of ROS and an upregulation of CD40L that were inhibited by ascorbic acid or apocynin, an inhibitor of NADPH oxidase. Conclusions: This study shows that in patients undergoing coronary stenting CD40L is upregulated with a mechanism which is likely mediated by oxidative stress.