Reply: Statin Intolerance and Risk for Recurrent Myocardial Infarction, Coronary Heart Disease Events, and All-Cause Mortality

A Mechanism for Statin-Induced Susceptibility to Myopathy

This study aimed to identify a mechanism for statin-induced myopathy that explains its prevalence and selectivity for skeletal muscle, and to understand its interaction with moderate exercise. Statin-associated adverse muscle symptoms reduce adherence to statin therapy; this limits the effectiveness of statins in reducing cardiovascular risk. The issue is further compounded by perceived interactions between statin treatment and exercise. This study examined muscles from individuals taking statins and rats treated with statins for 4 weeks. In skeletal muscle, statin treatment caused dissociation of the stabilizing protein FK506 binding protein (FKBP12) from the sarcoplasmic reticulum (SR) calcium (Ca2+) release channel, the ryanodine receptor 1, which was associated with pro-apoptotic signaling and reactive nitrogen species/reactive oxygen species (RNS/ROS)-dependent spontaneous SR Ca2+ release events (Ca2+ sparks). Statin treatment had no effect on Ca2+ spark frequency in cardiac myocytes. Despite potentially deleterious effects of statins on skeletal muscle, there was no impact on force production or SR Ca2+ release in electrically stimulated muscle fibers. Statin-treated rats with access to a running wheel ran further than control rats; this exercise normalized FKBP12 binding to ryanodine receptor 1, preventing the increase in Ca2+ sparks and pro-apoptotic signaling. Statin-mediated RNS/ROS-dependent destabilization of SR Ca2+ handling has the potential to initiate skeletal (but not cardiac) myopathy in susceptible individuals. Importantly, although exercise increases RNS/ROS, it did not trigger deleterious statin effects on skeletal muscle. Indeed, our results indicate that moderate exercise might benefit individuals who take statins.

Therapeutic effect of irbesartan combined with atorvastatin calcium in the treatment of rats with coronary heart disease

This study aimed to investigate the therapeutic effect of irbesartan combined with atorvastatin calcium in the treatment of rats with coronary heart disease. One hundred sixty Wistar rats were selected to establish coronary heart disease model. Rats with coronary heart disease were randomly divided into 4 groups: Model, irbesartan, atorvastatin calcium and combination groups (irbesartan combined with atorvastatin calcium group). Rats in irbesartan group were treated with 50 mg/(kg.day) irbesartan; rats in atorvastatin calcium group were given atorvastatin calcium at a dose of 10 mg/(kg.day); rats in combination group were subjected to atorvastatin calcium at a dose of 10 mg/(kg.day) and irbesartan at a dose of 50 mg/(kg.day), while rats in model groups were given intragastric administration of normal saline at a dose of 2 ml/day. Serum lipids, including total cholesterol (TC), triglyceride (TG), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C) and TC/HDL-C, were measured by automatic biochemical analyzer. Expression of sPLA2-V in myocardium and aortic trunk of rats was detected by reverse transcription-PCR (RT-PCR) and western blot analysis. After treatment, levels of serum TC, TG, LDL-C, HDL-C and TC/HDL-C in rats of each treatment group were better than those in model group (p<0.05). Expression level of sPLA2-V in myocardium and aortic trunk in model group was significantly higher than that in other groups (p<0.05). Expression level of sPLA2-V in combination group was significantly lower than that in irbesartan and atorvastatin calcium groups (p<0.05). Combination of irbesartan and atorvastatin calcium is superior to irbesartan or atorvastatin calcium alone in the treatment of rats with coronary heart disease. The possible explanation is that the two drugs can reduce the expression of sPLA2-V in myocardium and aortic trunk, which in turn relieved atherosclerosis and achieved better therapeutic effect.