Muscle mitochondrial function is impaired in adults with type 1 diabetes

Aims: Type 1 diabetes has been associated with mitochondrial dysfunction. However, the mechanism of this dysfunction in adults remains unclear. Methods: A secondary analysis was conducted using data from several clinical trials measuring in-vivo and ex-vivo mitochondrial function in adults with type 1 diabetes ( n = 34, age 38.8 +/- 14.6 years) and similarly aged controls ( n = 59, age 44.6 +/- 13.9 years). In-vivo mitochondrial function was assessed before, during, and after isometric exercise with 31 phosphorous magnetic resonance spectroscopy. High resolution respirometry of vastus lateralis muscle tissue was used to assess ex-vivo measures. Results: In-vivo data showed higher rates of anaerobic glycolysis ( p = 0.013), and a lower maximal mitochondrial oxidative capacity ( p = 0.012) and mitochondrial efficiency ( p = 0.024) in adults with type 1 diabetes. After adjustment for age and percent body fat maximal mitochondrial capacity ( p = 0.014) continued to be lower and anaerobic glycolysis higher ( p = 0.040) in adults with type 1 diabetes. Ex-vivo data did not demonstrate significant differences between the two groups. Conclusions: The in-vivo analysis demonstrates that adults with type 1 diabetes have mitochondrial dysfunction. This builds on previous research showing in-vivo mitochondrial dysfunction in youths with type 1 diabetes and suggests that defects in substrate or oxygen delivery may play a role in in-vivo dysfunction.