Vitamin C Research Today is a free monthly online journal that collates and summarizes the latest research about Vitamin C, including details on benefits, dosage, supplements, information.

Vitamin C inhibits platelet expression of CD40 ligand.

Pignatelli P, Sanguigni V, Paola SG, Lo Coco E, Lenti L, Violi F

Department of Experimental Medicine and Pathology, University of Rome La Sapienza, Divisione IV Clinica Medica, Policlinico Umberto I, Viale del Policlinico, 00185, Rome, Italy.

Upon stimulation with agonists, platelets express CD40 ligand (CD40L), a transmembrane protein implicated in the initiation and progression of atherosclerotic disease. We have recently discovered that oxidative stress plays a major role in platelet CD40L expression. In this study, we sought to determine whether vitamin C, a known antioxidant, is able to influence platelet CD40L expression. In vitro experiments were done by stimulating platelets with collagen in the presence or absence of vitamin C (50-100 microM) or vehicle as control. An in vivo study was done in 10 healthy subjects who were randomized to intravenous infusion of placebo or 1 g vitamin C for 45 min in a crossover design. At the end of infusion platelet CD40L and O2- were measured. The in vitro study demonstrated that vitamin C dose dependently inhibited platelet CD40L expression without affecting agonist-induced platelet aggregation. In subjects treated with placebo no changes of platelet CD40L and O2- were observed; conversely, vitamin C infusion caused a significant and parallel decrease of platelet O2- (-70%, P < 0.001) and CD40L (-68%, P < 0.001). Platelet aggregation was not modified by either treatment. This study suggests that water-soluble antioxidants, which scavenge superoxide radicals, may reduce platelet CD40L expression.

Published 26 May 2005 in Free Radic Biol Med, 38(12): 1662-6.
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