MicroRNAs (miRNAs) play a key role in the regulation of genes for normal metabolism in the liver. Dysregulation of miRNAs is involved in the development and progression of non-alcoholic fatty liver disease (NAFLD). We aimed to explore changes in circulating miRNA expression in response to delta-tocotrienol (δT3) and alpha-tocopherol (αTF) supplementation and correlate them with relevant biochemical markers in patients with NAFLD. In total, 100 patients with NAFLD were randomized to either receive δT3 (n = 50) 300 mg or αTF (n = 50) 268 mg twice/day for 48 weeks. Plasma expression of miRNA-122, -21, -103a-2, -421, -375 and -34a were determined at baseline, 24 and 48 weeks of intervention using RT-qPCR. Both δT3 and αTF significantly downregulated expression of miRNA-122, -21, -103a-2, -421, -375 and -34a. Moreover, δT3 was more effective than αTF in reducing expression of miRNA-375 and -34a. A significant correlation was observed between miRNA expression and biochemical markers of hepatic steatosis, insulin resistance (IR), oxidative stress (OS), inflammation and apoptosis. δT3 and αTF exert hepato-protective effects by downregulating miRNAs involved in hepatic steatosis, IR, OS, inflammation and apoptosis in patients with NAFLD. Furthermore, δT3 has more pronounced effects than αTF in reducing miR-375 and miR-34a, which are linked to regulation of inflammation and apoptosis.
Keywords: apoptosis; circulating microRNAs; inflammation; non-alcoholic fatty liver disease; α-tocopherol; δ-tocotrienol.