Influence of physical training on formation of muscle capillaries in type I diabetes
1984
Wallberg-Henriksson, Harriet | Gunnarsson, R (Rolf) | Henriksson, Jan | Östman, Jan | Wahren, John
Extract: The effects of physical training on skeletal muscle morphology and enzyme activities were compared in 10 male, type I diabetic subjects and 10 healthy, male, control subjects. The training program consisted of running for 45 minutes, 3 times per week for 8 weeks. Muscle biopsies were obtained before and after the training period from the lateral portion of the gastrocnemius muscle. Pretraining maximal oxygen uptake was similar in the 2 groups (diabetic subjects 42 versus control subjects 43 mg/kg-min), and the training resulted in an identical increase (+13%). Muscle capillarization (number of capillaries per muscle fiber) increased on the average in the control group (+14%), but was unchanged in the diabetic group (0%). Capillary density, expressed as number of capillaries per unit muscle cross sectional area, also increased on the average in controls (8%) but failed to do so in the diabetic patients (-8%). The activities of the mitochondrial enzymes citrate synthase (+26-27%) and succinate dehydrogenase (+24-25%) increased significantly and similarly in the 2 groups, whereas training did not result in significant changes in the activities of the glycolytic enzymes 6-phosphofructokinase and glyceraldehyde-phosphate dehydrogenase. Glycemic control in the diabetic group did not improve with the training, as evaluated from hemoglobin A1 and home-monitored blood glucose. The findings suggest that, compared with controls, the ability to form new skeletal muscle capillaries in response to physical training may be deficient in patients with type I diabetes mellitus of long standing, while the increase in mitochondrial enzyme activities is normal. A deficient formation of new capillaries may be an expression of the microangiopathy of this disorder. (author)
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