Foot Muscle Energy Reserves in Diabetic Patients Without and With Clinical Peripheral Neuropathy

Objective: To investigate changes in the foot muscle energy reserves in diabetic non-neuropathic and neuropathic patients. Research Design and Methods: We measured the phosphocreatinine (PCr)/inorganic phosphate (Pi) ratio, total $^{31}$P concentration, and the lipid/water ratio in the muscles in the metatarsal head region using MRI spectroscopy in healthy control subjects and non-neuropathic and neuropathic diabetic patients. Results: The PCr/Pi ratio was higher in the control subjects (3.23 $\pm$ 0.43) followed by the non-neuropathic group (2.61 $\pm$ 0.36), whereas it was lowest in the neuropathic group (0.60 $\pm$ 1.02) (P < 0.0001). There were no differences in total $^{31}$P concentration and lipid/water ratio between the control and non-neuropathic groups, but both measurements were different in the neuropathic group (P < 0.0001). Conclusions: Resting foot muscle energy reserves are affected before the development of peripheral diabetic neuropathy and are associated with the endothelial dysfunction and inflammation