Effect of Simvastatin Withdrawal on Ocular Endothelial Function

Statins are drugs representing the most commonly prescribed medication for the treatment of hypercholesterolemia. In a recently published study, discontinuation of statin therapy in patients after acute myocardial infarction was associated with a higher all-cause mortality (hazard ratio 3,45) and a higher cardiac mortality (hazard ratio 4,65). Increasing evidence suggests that statins also have vasoactive properties by up-regulating endothelial nitric oxide synthase (eNOS) with positive effects on endothelial function. Experiments with flow-mediated vasodilatation (FMD) showed these positive effects of statin treatment on endothelial function but also revealed that withdrawal of statin treatment transiently worsens endothelial function, independently of serum cholesterol levels. Consequently, this placebo controlled Phase IV crossover study wants to assess changes of endothelial function in terms of flicker induced vasodilatation before and during statin therapy as well as after statin withdrawal. For this purpose 20 healthy subjects will be treated with 40 mg/day of simvastatin for a period of 4 weeks. Flicker induced vasodilatation and retinal oxygen saturation will be measured with the Dynamic Vessel Analyzer system by Imedos at baseline, in the 4th week of simvastatin or placebo intake as well as 3, 7 and 14 days after the end of intake.