Immediate Antioxidant and Antiplatelet Effect of Atorvastatin via Inhibition of Nox2

Abstract

BACKGROUND: Statins exert an antithrombotic effect in patients at risk of or with acute thrombosis, but no study has investigated whether this effect is immediate and whether there is an underline mechanism. METHODS AND RESULTS: Patients with hypercholesterolemia were randomly allocated to a Mediterranean diet with low cholesterol intake (<300 mg/d; n=15) or atorvastatin (40 mg/d; n=15). Oxidative stress, as assessed by serum Nox2 and urinary isoprostanes, and platelet activation, as assessed by platelet recruitment, platelet isoprostanes, and thromboxane A(2), platelet Nox2, Rac1, p47(phox), protein kinase C, vasodilator-stimulated phosphoprotein, nitric oxide, and phospholipase A(2), were determined at baseline and after 2, 24, and 72 hours and 7 days of follow-up. An in vitro study was also performed to see whether atorvastatin affects platelet oxidative stress and activation. The atorvastatin-assigned group showed a significant and progressive reduction of urinary isoprostanes and serum Nox2, along with inhibition of platelet recruitment, platelet isoprostanes, Nox2, Rac1, p47(phox), and protein kinase C, starting 2 hours after administration. Platelet phospholipase A(2) and thromboxane A(2) significantly decreased and vasodilator-stimulated phosphoprotein and nitric oxide increased after 24 hours. Low-density lipoprotein cholesterol decreased significantly after 72 hours and further declined after 7 days. No changes were observed in the Mediterranean diet group. In vitro experiments demonstrated that atorvastatin dose-dependently inhibited platelet Nox2 and phospholipase A(2) activation, along with inhibition of platelet recruitment, platelet isoprostanes, and thromboxane A(2), and increased vasodilator-stimulated phosphoprotein and nitric oxide. CONCLUSIONS: The study provides the first evidence that atorvastatin acutely and simultaneously decreases oxidative stress and platelet activation by directly inhibiting platelet Nox2 and ultimately platelet isoprostanes and thromboxane A(2). These findings provide a rationale for the use of statins to prevent or modulate coronary thrombosis. CLINICAL TRIAL REGISTRATION: URL: http://www.clinicaltrials.gov. Unique identifier: NCT01322711.