Research article

Exercise training with dietary counselling increases mitochondrial chaperone expression in middle-aged subjects with impaired glucose tolerance

Mika Venojärvi^1,2,3 , Sirkka Aunola³ , Raivo Puhke⁴ , Jukka Marniemi³ , Helena Hämäläinen⁵ , Jukka-Pekka Halonen⁵ , Jaana Lindström⁶ , Merja Rastas⁷ , Kirsti Hällsten⁸ , Pirjo Nuutila⁸ , Osmo Hänninen¹ and Mustafa Atalay¹

¹Institute of Biomedicine, Physiology, University of Kuopio, POB 1627, FI-70211, Kuopio, Finland

²Medical Laboratory Technology, Turku University of Applied Sciences, Ruiskatu 8, FI-20721, Turku, Finland

³Department of Health and Functional Capacity, Laboratory for Population Research, National Public Health Institute, Turku, Finland

⁴Institute of Exercise Biology and Physiotherapy, University of Tartu, Tartu, Estonia

⁵Research Department, Social Insurance Institution, Turku, Finland

⁶Department of Health Promotion and Chronic Disease Prevention, Diabetes Unit, National Public Health Institute, Helsinki, Finland

⁷Department of Health Promotion and Chronic Disease Prevention, Nutrition Unit, National Public Health Institute, Helsinki, Finland

⁸Turku PET Centre, University of Turku, Turku, Finland

author email corresponding author email

BMC Endocrine Disorders 2008, 8:3doi:10.1186/1472-6823-8-3

Published:	27 March 2008

Abstract

Background

Insulin resistance and diabetes are associated with increased oxidative stress and impairment of cellular defence systems. Our purpose was to investigate the interaction between glucose metabolism, antioxidative capacity and heat shock protein (HSP) defence in different skeletal muscle phenotypes among middle-aged obese subjects during a long-term exercise and dietary intervention. As a sub-study of the Finnish Diabetes Prevention Study (DPS), 22 persons with impaired glucose tolerance (IGT) taking part in the intervention volunteered to give samples from the vastus lateralis muscle. Subjects were divided into two sub-groups (IGTslow and IGTfast) on the basis of their baseline myosin heavy chain profile. Glucose metabolism, oxidative stress and HSP expressions were measured before and after the 2-year intervention.

Results

Exercise training, combined with dietary counselling, increased the expression of mitochondrial chaperones HSP60 and glucose-regulated protein 75 (GRP75) in the vastus lateralis muscle in the IGTslow group and that of HSP60 in the IGTfast group. In cytoplasmic chaperones HSP72 or HSP90 no changes took place. In the IGTslow group, a significant positive correlation between the increased muscle content of HSP60 and the oxygen radical absorbing capacity values and, in the IGTfast group, between the improved VO_2max value and the increased protein expression of GRP75 were found. Serum uric acid concentrations decreased in both sub-groups and serum protein carbonyl concentrations decreased in the IGTfast group.

Conclusion

The 2-year intervention up-regulated mitochondrial HSP expressions in middle-aged subjects with impaired glucose tolerance. These improvements, however, were not correlated directly with enhanced glucose tolerance.