Altered glutathione system is associated with the presence of distal symmetric peripheral polyneuropathy in type 2 diabetic subjects

Distal symmetric peripheral polyneuropathy (DSPN) is a highly prevalent complication of diabetes. However, underlying pathophysiological mechanisms are multiple and not well understood. The aim of our study was to analyze the oxidative stress levels in circulating mononuclear cells by measuring the glutathione system, malondialdehyde and oxidized-LDL, in 60 type 2 diabetic patients from a well-characterized cohort of 196 type 2 diabetic patients. Using a nested case-control design, we studied 30 type 2 diabetic patients with distal symmetric polyneuropathy and 30 diabetic controls without this complication, according to the Neuropathy Disability Score. We have found that diabetic patients with distal symmetric polyneuropathy showed significantly lower values of reduced glutathione (GSH) and reduced glutathione/oxidized glutathione (GSH/GSSG) ratio. These data indicate an increased consumption of glutathione in mononuclear cells from patients with distal symmetric polyneuropathy. No significant differences were found in malondialdehyde or in oxidized-LDL levels comparing both groups. These data show an altered glutathione response in circulating monocytes from diabetic patients with distal symmetric polyneuropathy. (C) 2015 Elsevier Inc. All rights reserved.