Postexercise phosphocreatine recovery, an index of mitochondrial oxidative phosphorylation, is reduced in diabetic patients with lower extremity complications

Objective To identify differences in postexercise phosphocreatine (PCr) recovery, an index of mitochondrial function, in diabetic patients with and without lower extremity complications. Methods We enrolled healthy control subjects and three groups of patients with type 2 diabetes mellitus: without complications, with peripheral neuropathy, and with both peripheral neuropathy and peripheral arterial disease. We used magnetic resonance spectroscopic measurements to perform continuous measurements of phosphorous metabolites (PCr and inorganic phosphate [Pi]) during a 3-minute graded exercise at the level of the posterior calf muscles (gastrocnemius and soleus muscles). Micro- and macrovascular reactivity measurements also were performed. Results The resting Pi/PCr ratio and PCr at baseline and the maximum reached during exercise were similar in all groups. The postexercise time required for recovery of Pi/PCr ratio and PCr levels to resting levels, an assessment of mitochondrial oxidative phosphorylation, was significantly higher in diabetic patients with neuropathy and those with both neuropathy and peripheral arterial disease ( P P P Conclusions Mitochondrial oxidative phosphorylation is impaired only in type 2 diabetes mellitus patients with neuropathy whether or not peripheral arterial disease is present and is associated with the increased proinflammatory state observed in these groups.