Statins and stroke

Inhibitors of HMG-CoA reductase (statins) are potent cholesterol-lowering drugs. Large clinical trials have shown that statins reduce the incidence of cerebrovascular events, which might be surprising because cholesterol is not an established risk factor for stroke. In addition to their cholesterol-lowering properties, statins exert a number of pleiotropic, vasculoprotective actions that include improvement of endothelial function, increased nitric oxide (NO) bioavailability, antioxidant properties, inhibition of inflammatory responses, immunomodulatory actions, regulation of progenitor cells, and stabilization of atherosclerotic plaques. In fact, statins augment cerebral blood flow and confer significant protection in animal models of stroke partly via mechanisms related to the upregulation of endothelial nitric oxide synthase. Retrospective clinical evidence suggests that long-term statin administration may not only reduce stroke risk but also improve outcome. Early secondary prevention trials are underway to test the hypothesis that statin treatment initiated immediately after an event improves short-term outcome. Lastly, recent evidence suggests that sudden discontinuation of statin treatment leads to a rebound effect with downregulation of NO production. Withdrawal of statin treatment may impair vascular function and increase morbidity and mortality in patients with vascular disease.