Systemic redox imbalance in patients with nonalcoholic fatty liver disease

Background Oxidative stress is one of the major pathologic mechanisms for the progression of nonalcoholic fatty liver disease (NAFLD). The aim of this study was to evaluate the relationship between the extent of steatosis and oxidative stress parameters in patients with NAFLD. Methods The data obtained from 122 patients with NAFLD and 106 healthy controls aged 20-60 years with body mass index (BMI) ranging from 25 to 35 kg/m(2). Abdominal ultrasonography was performed in participants in order to the grading of hepatic steatosis. Fasting blood samples and anthropometric measurements were collected for all study subjects. Oxidative stress was evaluated by measurement of serum malondialdehyde (MDA), oxidized low-density lipoprotein (ox-LDL), total antioxidant capacity (TAC) and erythrocyte superoxide dismutase (SOD) as well as glutathione peroxidase (GPx) activities. Results Serum levels of liver enzymes (P < .0001) and MDA (P = .018), as well as erythrocyte SOD activity (P < .0001), were significantly higher in patients with NAFLD compared to healthy controls. Furthermore, patients with NAFLD had significantly lower serum TAC levels compared to healthy controls (P < .0001). No significant differences were observed in serum ox-LDL level and erythrocyte GPx activity between the groups. The probability of being NAFLD increased with increasing serum levels of MDA (P = .020) and SOD activity (P < .0001). In contrast, decreased serum TAC levels predicted the probability of being NAFLD (P < .0001). Conclusions Increased extent of hepatic steatosis could be considered as a pathological mechanism for enhancing oxidative stress in patients with NAFLD, independent of obesity, and is exacerbated further in patients with more severe condition.