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

Assessment of melatonin's therapeutic effectiveness against hepatic steatosis induced by a high-carbohydrate high-fat diet in rats

Several studies have demonstrated the protective effects of melatonin against metabolic diseases, such as liver steatosis. However, its therapeutic effects have received less scrutiny. The present study aimed to explore melatonin's therapeutic effectiveness in treating non-alcoholic fatty liver disease (NAFLD) induced by a high-carbohydrate high-fat (HCHF) diet in rats. The NAFLD was developed in male Wistar rats using an HCHF diet for 8 weeks. Afterward, they were given melatonin orally for four weeks at doses of 5 mg/kg, 10 mg/kg, and 30 mg/kg, along with the HCHF diet. In addition, six age-matched healthy rats received the highest dose of melatonin (30 mg/kg) for the same duration. Rats on the HCHF diet exhibited obesity, dyslipidemia, hyperglycemia, glucose intolerance, insulin resistance, inflammation, oxidative stress, and liver injury (steatosis). Melatonin treatment at 10 mg/kg and 30 mg/kg reduced body weight, adiposity index, oxidative damage, and inflammation but did not affect impaired glucose metabolism induced by the HCHF diet. Meanwhile, the highest dose of melatonin (30 mg/kg) reduced the liver steatosis index in HCHF rats but caused mild liver damage in healthy rats. In conclusion, using melatonin demonstrated positive outcomes in treating NAFLD induced by the HCHF diet in rats, with no noteworthy effects observed in healthy rats. A moderate dosage of 10 mg/kg of melatonin proved to be a safer and more efficient method for reducing HCHF diet-induced NAFLD in rats. Higher melatonin doses should be cautiously administered due to potential disruptions in lipid metabolism and the risk of liver complications.

Therapeutic potential of melatonin in targeting molecular pathways of organ fibrosis

Fibrosis, the excessive deposition of fibrous connective tissue in an organ in response to injury, is a pathological condition affecting many individuals worldwide. Fibrosis causes the failure of tissue function and is largely irreversible as the disease progresses. Pharmacologic treatment options for organ fibrosis are limited, but studies suggest that antioxidants, particularly melatonin, can aid in preventing and controlling fibrotic damage to the organs. Melatonin, an indole nocturnally released from the pineal gland, is commonly used to regulate circadian and seasonal biological rhythms and is indicated for treating sleep disorders. While it is often effective in treating sleep disorders, melatonin's anti-inflammatory and antioxidant properties also make it a promising molecule for treating other disorders such as organ fibrosis. Melatonin ameliorates the necrotic and apoptotic changes that lead to fibrosis in various organs including the heart, liver, lung, and kidney. Moreover, melatonin reduces the infiltration of inflammatory cells during fibrosis development. This article outlines the protective effects of melatonin against fibrosis, including its safety and potential therapeutic effects. The goal of this article is to provide a summary of data accumulated to date and to encourage further experimentation with melatonin and increase its use as an anti-fibrotic agent in clinical settings.

Shift work and nonalcoholic fatty liver disease incidence among Chinese rail workers: a 4-year longitudinal cohort study

PURPOSE

Occupational harmful factors, such as shift work, are attracting increasing attention as a potential cause of nonalcoholic fatty liver disease (NAFLD). In this study, we aimed to identify the association between shift work and NAFLD incidence in Chinese rail population.

METHODS

A cohort study was conducted among 14,112 rail workers for 4-year follow-up. Shift work frequency and other potential variables were recorded by questionnaires, including demographic, lifestyle, and occupation information. Besides, body mass index, blood pressure, fasting blood glucose, total cholesterol, triglyceride, alanine aminotransferase, and aspartate aminotransferase were measured by anthropometric measurement and blood test. Diagnosis of new NAFLD case was based on abdominal ultrasonography. Cox proportional hazards regression model was used to determine whether shift work has effect on occurrence of NAFLD.

RESULTS

The incidence of NAFLD was 30.43% in total subjects. After adjustment for possible confounders, the RRs of NAFLD were 1.069 (95% CI 0.998-1.146) and 1.179 (95% CI 1.059-1.312) in occasionally shift work group and frequently shift work group respectively, compared to the seldom shift work group. In stratified analyses, the RRs of NAFLD incidence linked to shift work exposure seems increase among female and elder. The results of three sensitivity analyses were similar with main analysis.

CONCLUSIONS

This research provided further evidence of positive harmful effect of shift work on NAFLD incidence in Chinese rail workers, particularly in frequently shift work population. The risk estimate of shift work on NAFLD was higher in female and elder.