Coffee Compounds Protection Against Lipotoxicity Is Associated with Lipid Droplet Formation and Antioxidant Response in Primary Rat Hepatocytes.

Metabolic dysfunction associated with steatotic liver disease (MASLD) is the result of disturbed lipid metabolism. In MASLD, the accumulation of free fatty acids (FFAs) in hepatocytes causes lipotoxicity mediated by oxidative stress. Coffee compounds are known for their beneficial effects in MASLD; however, the mechanisms still need to be further explored. The aim of this study was to elucidate the protective mechanisms of coffee compounds against palmitate-induced lipotoxicity in primary hepatocytes.

Methods: Primary hepatocytes were isolated from male Wistar rats and treated with palmitate (1 mmol/L) in combination with caffeine (CF: 1 mmol/L) or chlorogenic acid (CGA: 5 µmol/L). Mitochondrial ROS production, palmitate-induced necrosis, antioxidant response, ER stress markers and lipid droplet (LD) formation were assessed. Monoacylglycerols 2-SG (2-Stearolylglycerol), 2-OG (2-Oleoylglycerol) and SCD-1 (Stearoyl-CoA Desaturase 1) inhibitors were used to modulate LD formation. LD formation in steatotic Zucker rat hepatocytes was also investigated.

Results: CF and CGA prevented palmitate-induced cell death and reduced ROS production. CF and CGA induced the antioxidant response, especially HO-1 expression, but had no significant effect on ER stress markers. CF and CGA increased LD formation in palmitate-treated cells. This effect was significantly reduced by 2-SG and SCD-1 inhibitors but enhanced by 2-OG. Lipid droplets were associated with lower palmitate toxicity and reduced ROS production.

Conclusions: CF and CGA protect hepatocytes from lipotoxicity via modulation of the antioxidant response and enhance lipid droplet formation via an SCD-1-dependent mechanism. Oxidative stress-related toxicity in hepatocytes can be prevented by enhancing LD formation.