Oxidative stress markers are increased in non-alcoholic fatty liver disease patients with high serum alanine aminotransferase levels

Introduction
Non-alcoholic fatty liver disease (NAFLD) is a pathological disease that causes chronic damage in the liver without alcohol consumption.

Aim of the research
To determine oxidative stress and inflammation statuses (NAFLD) with increased alanine aminotransferase (ALT).

Material and methods
Oxidative stress (malondialdehyde (MDA), advanced oxidation protein products (AOPP), inflammation (serum tumour necrosis factor-α (TNF-α)), interleukin-6 (IL-6), and hyaluronic acid (HA) were measured by the ELISA method or manually. A total of 133 non-obese and non-diabetic individuals were included. Patients diagnosed with NAFLD with normal ALT levels were included in group 1 (n = 53), and those with high ALT levels were included in group 2 (n = 35). The control group included individuals without any known systemic disease (n = 45).

Results
We found that the serum MDA levels were significantly elevated in group 2 in comparison to the control group (p < 0.05). However, there were no significant changes in the serum AOPP levels in any group (p > 0.05). The serum TNF-α and IL-6 levels of group 1 and group 2 were higher than those in the control group (p < 0.05). The serum HA levels in group 2 increased significantly in comparison to the other groups (p < 0.05).

Conclusions
HA and MDA were enhanced with high ALT levels and with elevated TNF-α and IL-6 levels without high ALT levels in NAFLD.