New insights into mechanisms of statin-associated myotoxicity

Statin drugs represent a major improvement in the treatment of hypercholesterolemia that constitutes the main origin of atherosclerosis, leading to coronary heart disease. Besides the tremendous beneficial effects of statins, various forms of muscular toxicity (myalgia, cramp, exercise intolerance, fatigability) occur frequently. Many hypotheses were proposed to explain statin myotoxicity. The goal of this review is to highlight some of the most recent findings that can account for interpreting the pathophysiological mechanisms for statin-induced myotoxicity. Statin-induced myotoxicity appears multifactorial. Apart from the deleterious effect due to a reduction in cholesterol biosynthesis, statins have a direct effect on the respiratory chain of the mitochondria. It is proposed that mitochondrial impairment leads to a mitochondrial calcium leak that directly interferes with the regulation of sarcoplasmic reticulum calcium cycling without excluding a direct effect of statin on the sarcoplasmic reticulum. Both mitochondrial and calcium impairments may account for apoptosis process, oxidative stress, and muscle remodeling and degeneration that have been extensively reported to explain statin myotoxicity and functional symptoms described by treated patients.