Impact of hyperglycaemia on molecular markers of oxidative stress and antioxidants in type 2 diabetes mellitus

Abstract

Introduction. The pathogenesis of type 2 diabetes mellitus (T2DM) is strongly linked to oxidative stress mainly caused by chronic hyperglycaemia. The present study investigates the association between hyperglycaemia with oxidative stress markers, antioxidants and lipid profile. Materials and methods. The case-control study involved two groups, T2DM patients (n = 83) and age and sex matched controls (n = 81). Serum levels of various molecular markers malondialdehyde (MDA), reactive oxygen species (ROS) and nitric oxide (NO), superoxide dismutase (SOD), catalase (CAT), glutathione (GSH), vitamin C, total antioxidant capacity (TAC) and lipid parameters total cholesterol, triglycerides, low density lipoprotein (LDL) and high density lipoprotein (HDL) were measured using spectrophotometric assays. Results were analysed to compare and correlate glycaemic levels with these molecular markers. Results. T2DM patients had a higher body mass index (BMI) and body fat percentage. 2 hour blood glucose, glycated haemoglobin A 1c % (HbA 1c), total cholesterol, triglycerides and LDL were higher in diabetics, HDL was found to be lower in diabetics than in controls. Mean levels of enzymatic and non-enzymatic antioxidants SOD, CAT, GSH, vitamin C and TAC were significantly lower while oxidative stress markers NO, ROS and MDA were higher in T2DM patients. NO showed a positive correlation (r = 0.3993, p < 0.0001) whereas TAC showed a negative correlation with glycaemia (r =-0.4796, p < 0.0001). Conclusions. Poor glycaemic control in T2DM causes elevated ROS and NO levels with increased lipid peroxidation and lowered antioxidant capacity. MDA and NO being the major risk factors could be used as a parameter along with antioxidants to assess oxidative stress in T2DM patients.

Oxidative stress parameters and keap 1 variants in T2DM: Association with T2DM, diabetic neuropathy, diabetic retinopathy, and obesity

“…Negative correlation between TAC level and glycemic level has been indicated as with increased hyperglycemia in T2DM, the plasma antioxidant capacity is worsening. However, there are inconsistent results as an increased TAC levels in these patients have been reported in some studies 28 …”

Ameliorative effect of polydatin and polydatin-loaded chitosan nanoparticles against diabetes-induced pulmonary disorders in rats

“…Oxidative stress is a serious pathological pathway for T2DM [38], which increase cell stress and lead to a reduction in antioxidant intracellular defenses. Furthermore, MDA has been obviously elevated [39] and enzymatic antioxidants SOD, CAT, GSH were significantly lower in diabetic animals [40]. Inflammatory and apoptotic markers including NF-κβ, TNF α, Nrf2, and HO-1 protein, and gene expression were induced after the production of mitochondrial ROS caused by oxidative damage [41].…”

Commentary: The Effects of Inflammation, Aging, and Oxidative Stress on the Pathogenesis of Type II Diabetes

“…Both aspects have a complex interaction in which there is mutual amplification, which can be termed as a "vicious cycle" or a positive feedback mechanism [4, 19,20]. Although [3] fails to provide an explicit link between oxidative stress and T2DM, [19,21,22] discuss that a hyperglycaemic state can result in elevation of DNA damage markers, and products of protein and lipid peroxidation, all of which lower enzymatic activity of antioxidants. Also, exposure of pancreatic beta-cell lines to oxidative stress inhibits insulin gene expression through reduced mRNA expression, which yields chronic insulin resistance, induced by chronic hyperglycemia [16,23,24].…”