Melatonin Levels in Patients with Nonalcoholic Fatty Liver Disease Compared with Healthy Individuals according to Fibrosis Level

BACKGROUND: Non-alcoholic fatty liver disease (NAFLD) is one of the most common diseases worldwide. Studies have shown that melatonin, as a regulatory hormone, is effective in different cell protective pathways. We aimed to compare serum melatonin levels of patients with NAFLD with different stages of fibrosis with that of healthy individuals. METHODS:  In this cross-sectional study patients, aged >20 years with elevated serum liver enzymes and trance abdominal sonographic diagnosis of fatty liver who met the exclusion criteria for NAFLD were included. The participants were categorized into three groups as follows: 1) severe fibrosis (fibrosis> 9.1 kPa and steatosis >285 dbm), 2) mild-moderate fibrosis (fibrosis: 6-9.0 kPa and steatosis 240-285), and 3) normal group with fibrosis <5.8 kPa and steatosis< 240 dbm based on Fibroscan evaluation. Five ml of fasting venous blood was taken from each patient and the control group for laboratory assessment. A questionnaire including demographic, anthropometric, laboratories (serum ALT, AST, triglyceride, total cholesterol and melatonin level), and clinical data was completed for all participants.  RESULTS: 97 people with a mean±SD age of 42.21±11 years were enrolled. 59 (60.0%) patients were women. we observed that the melatonin levels were increased by advancing fibrosis. Based on control- attenuated parameter results the melatonin levels significantly differed between the healthy individuals and patients with severe steatosis. There was a direct association between increased melatonin levels and liver enzymes. CONCLUSION:  As a regulatory hormone, melatonin may directly be associated with liver cell injuries. Therefore, considered regulatory substances such as melatonin either diagnostic or therapeutic can improve the patients' outcome.