High Levels of HbA1c from T2DM Patients Positively Correlated with Increased of Oxidative Stress Biomarker and IL-6 Levels

Abstract

 Objective: To determine the association between Type 2 diabetes mellitus (T2DM) and inflammation based on the plasma levels of pro-inflammatory cytokines (IL-1b, IL-6, TNF-a and IFN-g), lipid peroxidation (malonaldehyde), vascular endothelial growth factor (VEGF) and C-reactive protein (CRP) associated with glycated hemoglobin (HbA1c). Methods: The expression of oxidative stress markers and the plasma levels of angiogenic factor and inflammatory cytokines were determined in 51 T2DM patients compared with 38 healthy controls. The levels of cytokines (IL-1b, IL-6, TNF-a and IFN-g), angiogenic factor (VEGF) and CRP were measured using ELISA. Lipid peroxidation (oxidative stress biomarker) was determined through malonaldehyde (MDA) levels using the TBARS assay, and HPLC was used to measure the HbA1c levels. Results: Correlation studies of the glycemic control (HbA1c levels) versus IL-6 levels and the HbA1c concentration versus MDA levels indicated a high positive correlation for T2DM patients (r = 0.68 and r = 0.67, respectively), but not for healthy controls (r = 0.32 and r = 0.16, respectively). The results also revealed higher plasma levels of IL-6, TNF-a, IL-1β, VEGF and MDA in T2DM patients compared with healthy controls (p<0.05); however, the plasma levels of IFN-g and CRP were similar between these groups (p>0.05). Conclusion: The results of this study show that the combined association of biomarkers for glycemic control (HbA1c) with pro-inflammatory cytokine (IL-6) and oxidative stress biomarker (MDA) might be a promising tool for the follow-up and evaluation of diabetes complications, although further studies are needed.