Supplementation of concentrated Kurozu, a Japanese black vinegar, reduces the onset of hepatic steatosis in mice fed with a high-fat diet

Background: Hepatic steatosis is among the most common causes of chronic liver diseases, although established effective treatments are not evident. Previous studies reported that Kurozu improved hypercholesterolemia and carbohydrate metabolism. However, the effect of Kurozu on the incidence of hepatic steatosis is not clear.Objective: The effect of Kurozu on the onset of hepatic steatosis by administering a high-fat diet (HFD) for 110 weeks was evaluated in C57BL/6J mice. Methods: HFD treatment for 110 weeks accelerated the onset of hepatic steatosis more than a standard diet, whereas concentrated Kurozu (CK) supplementation ameliorated the effect of an HFD feeding. The effect of supplementation with resveratrol in an HFD on the onset of hepatic steatosis was also evaluated. To elucidate the mechanism of the effect of Kurozu on the expression of lipid metabolism genes, acute treatment for 10 days with Kurozu was also examined.Results: Supplementation with resveratrol in HFD-fed mice did not ameliorate hepatic steatosis. Body weights were significantly lower in the CK + HFD and Resveratrol + HFD groups than in the control HFD group in middle age. No significant differences in all-cause mortality were observed following supplementation with CK or resveratrol. CK and resveratrol supplements significantly inhibited decreases in dehydroepiandrosterone sulphate serum levels at postnatal week 120. CK and resveratrol supplements did not affect the survival of mice. The ingestion of Kurozu for 10 days significantly elevated the expression levels of Sirt1, Pgc-1α, Lpin1, and Igfbp1 in the liver. Conclusion: These results suggest that ingesting CK may delay the onset of hepatic steatosis HFD feeding causes.Keywords: Kurozu, steatosis, Sirt1, Igfbp1, Lpin1, Pgc-1α, resveratrol