Endocrine Abstracts

Aim: In our study, we aimed to evaluate the relationship between oxidative stress markers such as total antioxidant capacity (TAC), advanced oxidant protein products (AOPP) and thiol-disulfide homeostasis parameters and diabetic peripheral neuropathy (PNP), an important microvascular complication of diabetes mellitus (DM).

Material and methods: 80 (male/female=34/46) patients with type 2 DM and 19 healthy controls were included in the study. All patients were assessed for PNP by Michigan Neuropathy Screening Test (MNTT) and Electroneuromyography (EMG). TAC, AOPP and total thiols, native thiols and disulfide levels of thiol-disulfide homeostasis parameters were studied in serum samples of patients and controls.

Results: There was no statistically significant difference between serum TAC, AOPP levels and thiol-disulfide homeostasis parameters when patients were grouped as those with and without PNP according to EMG or MNTT results. Regrouping was made and the patients were classified as having PNP if both EMG and MNTT results were positive. If both EMG and MNTT results were negative, they were classified as patients without PNP. Patients with discordant results were excluded. According to the regrouping, serum HbA1c (9.5±2.0% vs 8.0±1.8%; P=0.019) and triglyceride levels (204.4±77.0 vs 151.7±58.5 mg/dl, P=0.014) were significantly higher while serum total thiol levels (540.4±9.9 vs 566.7±2.6 μmol/l, P=0.038) were lower in diabetic patients with PNP compared to diabetic patients without PNP. There was no difference between serum TAC, AOPP, native thiol and disulfide levels in patients with and without PNP. However, when compared with the control group, serum CRP, AOPP, total thiol and native thiol levels were found higher in patients with type 2 DM (P=0.001, P=0.002, P=0.02 and P=0.03; respectively).

Conclusions: In our study, there was no significant increase in serum TAC, AOPP, and thiol-disulfide homeostasis parameters, which are indicative of oxidative stress, in diabetic patients with PNP compared to those without PNP. These results suggest that the oxidative stress parameters assessed in our study are more closely related to the presence of diabetes rather than the presence of PNP.