Fenofibrate, a peroxisome proliferator-activated receptor alpha agonist, reduces hepatic steatosis and lipid peroxidation in fatty liver Shionogi mice with hereditary fatty liver
LIVER INTERNATIONAL
Authors: Harano, Yuichi; Yasui, Kohichiroh; Toyama, Tetsuya; Nakajima, Tomoki; Mitsuyoshi, Hironori; Mimani, Masahito; Hirasawa, Tsutomu; Itoh, Yoshito; Okanoue, Takeshi
Abstract
Background and aims: The fatty liver Shionogi (FLS) mouse, a unique model for nonalcoholic fatty liver disease (NAFLD), is an inbred strain that develops spontaneous hepatic steatosis without obesity or diabetes mellitus. Peroxisome proliferator-activated receptor (PPAR) alpha controls fatty acid metabolism. In the present study, we investigated the effect of fenofibrate, a PPAR alpha agonist, on hepatic steatosis in FLS mice. Methods: Thirteen-week-old FLS mice were fed a diet with 0.1% fenofibrate (w/w) for 12 days. The degree of hepatic steatosis was estimated by histological examination and hepatic triglyceride levels. Expression levels of genes involved in fatty acid turnover, including Acox1, Cpt1a, Fabp1, Acadl, and Acadm, were determined by Northern blot analyses. We measured levels of lipid peroxidation, glutathione, and anti-oxidative enzymes, such as superoxide dismutase, catalase, and glutathione peroxidase, in the liver. Result: Treatment of FLS mice with fenofibrate improved hepatic steatosis by activating expression of genes involved in fatty acid turnover and decreased hepatic lipid peroxidation. Fenofibrate increased the activity of catalase by upregulating its mRNA levels. Conclusion: Fenofibrate, which is currently used in therapy of hyperlipidemia, might also be useful for treating patients with NAFLD even in cases where NAFLD is not associated with obesity or diabetes mellitus.
Up-regulation of hepatic fatty acid transporters and inhibition/down-regulation of hepatic OCTN2 contribute to olanzapine-induced liver steatosis
TOXICOLOGY LETTERS
Authors: Jiang, Ting; Zhang, Yingqiong; Bai, Mengru; Li, Ping; Wang, Wei; Chen, Mingyang; Ma, Zhiyuan; Zeng, Su; Zhou, Hui; Jiang, Huidi
Abstract
Olanzapine, a representative of antipsychotics, is a first-line drug for treatment of schizophrenia. However, olanzapine-induced liver steatosis limits its clinical utilization. This study is to explore the mechanism of liver steatosis induced by olanzapine based on the regulation of transporters involved in uptake and oxidation of fatty acids. Our results revealed that 12-week oral administration of olanzapine increased hepatic triglyceride(TG), caused liver steatosis. Our further studies showed that the expression of fatty acid transporter 2(FATP2) and fatty acid binding protein 1(FABP1) were up-regulated in liver of female mice after 12-week olanzapine exposure, as well as in primary mouse hepatocytes treated with olanzapine. Olanzapine treatment also reduced hepatic beta-hydroxybutyrate level (indicator of fatty acid beta-oxidation), meanwhile, the L-carnitine (L-Car) concentration in liver of olanzapine group was significantly lower than that in control group. Further study demonstrated that both mRNA and protein expression of hepatic OCTN2 (carnitine/organic cation transporter 2) were obviously down-regulated in male mice after 12-week olanzapine treatment. Also, olanzapine markedly inhibited L-Car uptake in MDCK-hOCTN2 cells (1.06 mu M of IC50), HepG2 cells and primary mouse hepatocytes. Supplementation of L-Car attenuated hepatic TG rise and improved simple steatosis in olanzapine treatment mice. Taken together, up-regulation of FATP2/FABP1 and down-regulation/inhibition of hepatic OCTN2 probably contribute to olanzapine-induced liver steatosis. Supplementation of L-Car is a promising strategy to attenuate olanzapineinduced simple steatosis.