Effects of exercise and creatine on myosin heavy chain isoform composition in patients with Charcot-Marie-Tooth disease

Muscle Nerve. 2006 Nov;34(5):586-94. doi: 10.1002/mus.20621.

Abstract

It is not known whether myosin heavy chain (MHC) content changes in response to exercise training or creatine supplementation in subjects with Charcot-Marie-Tooth disease (CMT). Based on previous data, we hypothesized that resistance exercise and creatine would increase the percentage of type I MHC composition in the vastus lateralis muscle and that myosin isoform changes would correlate with improved chair rise-time in CMT subjects. To test this hypothesis, 18 CMT subjects were randomly assigned to either a placebo or creatine group. All subjects performed a 12-week, home-based, moderate-intensity resistance training program. Chair rise-time was measured before and after the training program. Muscle biopsies were obtained from the vastus lateralis before and after the 12-week program. Gel electrophoresis showed a significant decrease (approximately 30%) in MHC type I in CMT subjects given creatine supplementation when compared with placebo. There was a nonsignificant increase in both MHC type IIa (approximately 23%) and MHC type IIx (approximately 7%) in CMT subjects given creatine. Reduced MHC type I content and increased MHC type IIa content correlated with faster chair rise-times (i.e., improved muscle performance). The training-induced change in MHC IIa content was inversely correlated with chair rise-time in CMT subjects given creatine. When the two subject groups were combined, there was a linear, negative relationship between the change in MHC type IIa content and chair rise-time after training and a positive relationship between the training-induced change in MHC type I content and chair rise-time. These data suggest that improved function (chair rise-time) was associated with a lower level of MHC type I and increased MHC type IIa composition. Furthermore, the data are consistent with the hypothesis that creatine supplementation alters MHC composition in CMT patients undergoing resistance training and that MHC changes associated with creatine supplementation can improve muscle function.

Publication types

  • Randomized Controlled Trial

MeSH terms

  • Adult
  • Biopsy
  • Charcot-Marie-Tooth Disease / metabolism*
  • Charcot-Marie-Tooth Disease / physiopathology
  • Charcot-Marie-Tooth Disease / therapy*
  • Creatine / pharmacology*
  • Creatine / therapeutic use
  • Dietary Supplements
  • Double-Blind Method
  • Exercise Test
  • Exercise Therapy / methods*
  • Exercise Tolerance / drug effects
  • Exercise Tolerance / physiology
  • Humans
  • Middle Aged
  • Muscle Contraction / drug effects
  • Muscle Contraction / physiology
  • Muscle, Skeletal / drug effects*
  • Muscle, Skeletal / metabolism
  • Muscle, Skeletal / physiopathology
  • Myosin Heavy Chains / genetics
  • Myosin Heavy Chains / metabolism*
  • Physical Fitness / physiology
  • Protein Isoforms / genetics
  • Protein Isoforms / metabolism
  • Quadriceps Muscle / drug effects
  • Quadriceps Muscle / metabolism
  • Quadriceps Muscle / physiopathology
  • Treatment Outcome

Substances

  • Protein Isoforms
  • Myosin Heavy Chains
  • Creatine