Prolonged exercise training increases intramuscular lipid content and perilipin 2 expression in type I muscle fibers of patients with type 2 diabetes

Am J Physiol Endocrinol Metab. 2012 Nov 1;303(9):E1158-65. doi: 10.1152/ajpendo.00272.2012. Epub 2012 Sep 4.

Abstract

The aim of the present study was to investigate changes in intramuscular triglyceride (IMTG) content and perilipin 2 expression in skeletal muscle tissue following 6 mo of endurance-type exercise training in type 2 diabetes patients. Ten obese male type 2 diabetes patients (age 62 ± 1 yr, body mass index BMI 31 ± 1 kg/m²) completed three exercise sessions/week consisting of 40 min of continuous endurance-type exercise at 75% V(O₂ peak) for a period of 6 mo. Muscle biopsies collected at baseline and after 2 and 6 mo of intervention were analyzed for IMTG content and perilipin 2 expression using fiber type-specific immunofluorescence microscopy. Endurance-type exercise training reduced trunk body fat by 6 ± 2% and increased whole body oxygen uptake capacity by 13 ± 7% (P < 0.05). IMTG content increased twofold in response to the 6 mo of exercise training in both type I and type II muscle fibers (P < 0.05). A threefold increase in perilipin 2 expression was observed from baseline to 2 and 6 mo of intervention in the type I muscle fibers only (1.1 ± 0.3, 3.4 ± 0.6, and 3.6 ± 0.6% of fibers stained, respectively, P < 0.05). Exercise training induced a 1.6-fold increase in mitochondrial content after 6 mo of training in both type I and type II muscle fibers (P < 0.05). In conclusion, this is the first study to report that prolonged endurance-type exercise training increases the expression of perilipin 2 alongside increases in IMTG content in a type I muscle fiber-type specific manner in type 2 diabetes patients.

Publication types

  • Clinical Trial

MeSH terms

  • Abdominal Fat / pathology
  • Adiposity
  • Body Mass Index
  • Cohort Studies
  • Diabetes Mellitus, Type 2 / complications
  • Diabetes Mellitus, Type 2 / metabolism*
  • Diabetes Mellitus, Type 2 / pathology
  • Diabetes Mellitus, Type 2 / therapy*
  • Exercise*
  • Humans
  • Insulin Resistance
  • Lipid Metabolism*
  • Male
  • Membrane Proteins / metabolism*
  • Middle Aged
  • Mitochondria, Muscle / metabolism
  • Mitochondria, Muscle / pathology
  • Muscle Fibers, Fast-Twitch / metabolism
  • Muscle Fibers, Fast-Twitch / pathology
  • Muscle Fibers, Slow-Twitch / metabolism*
  • Muscle Fibers, Slow-Twitch / pathology
  • Overweight / complications
  • Oxygen Consumption
  • Perilipin-2
  • Quadriceps Muscle / metabolism*
  • Quadriceps Muscle / pathology
  • Time Factors
  • Triglycerides / metabolism

Substances

  • Membrane Proteins
  • Perilipin-2
  • Triglycerides

Associated data

  • ISRCTN/ISRCTN32206301