Statins with different lipophilic indices exert distinct effects on skeletal, cardiac and vascular smooth muscle

Data concerning the influence of statin lipophilicity on the myotoxic and pleiotropic effects of statins is conflicting, and mechanistic head-to-head comparison studies evaluating this parameter are limited. In order to address the disparity, this mechanistic investigation aimed to assess the effects of two short-acting statins with different lipophilic indices on skeletal, cardiac and vascular smooth muscle physiology.

Young female Wistar rats were randomised to simvastatin (80 mg kg^-1 day^-1), pravastatin (160 mg kg^-1 day^-1) or control treatment groups. Changes in functional muscle performance were assessed, as well as mRNA levels of genes relating to atrophy, hypertrophy, mitochondrial function and/or oxidative stress.

There were no significant differences in the mRNA profiles of isolated skeletal muscles amongst the treatment groups. In terms of skeleletal muscle performance, simvastatin reduced functionality but treatment with pravastatin significantly improved force production. Rodents given simvastatin demonstrated comparable myocardial integrity to the control group. Conversely, pravastatin reduced left ventricular action potential duration, diastolic stiffness and Mhc-β expression. Pravastatin improved endothelium-dependent relaxation, particularly in muscular arteries, but this effect was absent in the simvastatin-treated rats. The responsiveness of isolated blood vessels to noradrenaline also differed between the statin groups. The findings of this study support that the effects of statins on skeletal, cardiac and vascular smooth muscle vary with their lipophilic indices.

The results of this work have important implications for elucidating the mechanisms responsible for the myotoxic and pleiotropic effects of statins.