title: Prolonged exercise training increases intramuscular lipid content and perilipin 2 expression in type I muscle fibers of patients with type 2 diabetes.
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.
authors.affiliation: School of Sport and Exercise Sciences, The University of Birmingham, Birmingham, United Kingdom.
authors.forename: C S
authors.initials: CS
authors.lastname: Shaw
authors.forename: S O
authors.initials: SO
authors.lastname: Shepherd
authors.forename: A J M
authors.initials: AJ
authors.lastname: Wagenmakers
authors.forename: D
authors.initials: D
authors.lastname: Hansen
authors.forename: P
authors.initials: P
authors.lastname: Dendale
authors.forename: L J C
authors.initials: LJ
authors.lastname: van Loon
mesh_terms: D050153:Abdominal Fat / Q000473:pathology; D050154:Adiposity; D015992:Body Mass Index; D015331:Cohort Studies; D003924:Diabetes Mellitus, Type 2 / Q000150:complications / Q000378:metabolism* / Q000473:pathology / Q000628:therapy*; D015444:Exercise; D006801:Humans; D007333:Insulin Resistance; D050356:Lipid Metabolism; D008297:Male; D008565:Membrane Proteins / Q000378:metabolism*; D008875:Middle Aged; D008931:Mitochondria, Muscle / Q000378:metabolism / Q000473:pathology; D018656:Muscle Fibers, Fast-Twitch / Q000378:metabolism / Q000473:pathology; D018657:Muscle Fibers, Slow-Twitch / Q000378:metabolism* / Q000473:pathology; D050177:Overweight / Q000150:complications; D010101:Oxygen Consumption; D000070780:Perilipin-2; D052097:Quadriceps Muscle / Q000378:metabolism* / Q000473:pathology; D013997:Time Factors; D014280:Triglycerides / Q000378:metabolism
chemical_list: D008565:Membrane Proteins; D000070780:Perilipin-2; D014280:Triglycerides