Differences in metabolites in pain-processing brain regions in patients with diabetes and painful neuropathy

OBJECTIVE - Magnetic resonance spectroscopy (MRS) (specifically, H-1-MRS) has been used to show changes in the brain following peripheral nerve injury in subjects without diabetes, This study used H-1-MRS to examine the brain in subjects with or without painful diabetic neuropathy. RESEARCH DESIGN AND METHODS - Twenty-six diabetic subjects (12 with and 14 without chronic neuropathic pain) were compared, with 18 subjects without diabetes and pain. The left thalamus, anterior cingulate cortex (ACC), and dorsolateral prefrontal cortex (DLPFC) were assessed using H-1-MRS. RESULTS - In the DLPFC, diabetic subjects had a decrease in N-acetyl aspartate (NAA) and creatine relative to the control group. In the thalamus, there was a reduction of NAA in the diabetic group with pain compared with that in patients with diabetes and no pain. CONCLUSION - Subjects with diabetes have metabolite differences in the brain compared with control subjects. Subjects with painful neuropathy showed reduced NAA in the thalamus, which may explain the genesis of pain in some cases.