Statins affect skeletal muscle performance: evidence for disturbances in energy metabolism.
J Clin Endocrinol Metab. 2017 Oct 9. Epub 2017 Oct 9. PMID: 29040646
Neeltje A E Allard
Context: Statin myopathy is linked to disturbances in mitochondrial function and exercise intolerance.
Objectives: To determine whether differences exist in exercise performance, muscle function and mitochondrial oxidative capacity and content between symptomatic and asymptomatic statin users, and non-statin using controls.
Design: Cross-sectional study.
Setting: Department of Physiology of the Radboud University Medical Center.
Participants: Long-term symptomatic (n=10) and asymptomatic (n=10) statin users, and controls (n=10).
Interventions: Maximal incremental cycling tests and involuntary electrically stimulated isometric quadriceps muscle contractions were performed and a muscle biopsy was obtained from the vastus lateralis muscle.
Main outcomes measured: Maximal exercise capacity, substrate utilization during exercise, muscle function, and mitochondrial energy metabolism.
Results: VO2peak, maximal work load and ventilatory efficiency were comparable between groups, but both statin groups had a depressed anaerobic threshold compared to controls (p=0.01). Assessment of muscle fatigability by a two-minute stimulation protocol revealed a prolonged relaxation time in both statin groups compared to controls (ptime*group<0.001), and a decrease in rate of maximal force rise (ptime*group<0.001). Mitochondrial activity of complexes (C) II and IV was lower in symptomatic statin users than controls and tended to be lower for CIII (CII: p=0.03; CIII: p=0.05; CIV: p=0.04). Mitochondrial content tended to be lower in both statin groups than controls (p=0.08).
Conclusions: Statin use attenuates substrate use during maximal exercise performance, induces muscle fatigue during repeated muscle contractions and decreases mitochondrial oxidative capacity of the muscle. This suggests that disturbances in mitochondrial oxidative capacity occur with statin use even in subjects without statin-induced muscle complaints.