Overview of emerging treatment of non-alcoholic fatty liver disease: more than one drug needed?

Hepatoprotective effects of Xiaoyao San formula on hepatic steatosis and inflammation via regulating the sex hormones metabolism

BACKGROUND

The modified Xiaoyao San (MXS) formula is an adjuvant drug recommended by the National Health Commission of China for the treatment of liver cancer, which has the effect of preventing postoperative recurrence and metastasis of hepatocellular carcinoma and prolonging patient survival. However, the molecular mechanisms underlying that remain unclear.

AIM

To investigate the role and mechanisms of MXS in ameliorating hepatic injury, steatosis and inflammation.

METHODS

A choline-deficient/high-fat diet-induced rat nonalcoholic steatohepatitis (NASH) model was used to examine the effects of MXS on lipid accumulation in primary hepatocytes. Liver tissues were collected for western blotting and immunohistochemistry (IHC) assays. Lipid accumulation and hepatic fibrosis were detected using oil red staining and Sirius red staining. The serum samples were collected for biochemical assays and NMR-based metabonomics analysis. The inflammation/lipid metabolism-related signaling and regulators in liver tissues were also detected to reveal the molecular mechanisms of MXS against NASH.

RESULTS

MXS showed a significant decrease in lipid accumulation and inflammatory response in hepatocytes under metabolic stress. The western blotting and IHC results indicated that MXS activated AMPK pathway but inhibited the expression of key regulators related to lipid accumulation, inflammation and hepatic fibrosis in the pathogenesis of NASH. The metabonomics analysis systemically indicated that the arachidonic acid metabolism and steroid hormone synthesis are the two main target metabolic pathways for MXS to ameliorate liver inflammation and hepatic steatosis. Mechanistically, we found that MXS protected against NASH by attenuating the sex hormone-related metabolism, especially the metabolism of male hormones.

CONCLUSION

MXS ameliorates inflammation and hepatic steatosis of NASH by inhibiting the metabolism of male hormones. Targeting male hormone related metabolic pathways may be the potential therapeutic approach for NASH.

PPAR-γ signaling in nonalcoholic fatty liver disease: Pathogenesis and therapeutic targets

Non-alcoholic fatty liver disease (NAFLD), currently the leading cause of global chronic liver disease, has emerged as a major public health problem, more efficient therapeutics of which are thus urgently needed. Peroxisome proliferator-activated receptor γ (PPAR-γ), ligand-activated transcription factors of the nuclear hormone receptor superfamily, is considered a crucial metabolic regulator of hepatic lipid metabolism and inflammation. The role of PPAR-γ in the pathogenesis of NAFLD is gradually being recognized. Here, we outline the involvement of PPAR-γ in the pathogenesis of NAFLD through adipogenesis, insulin resistance, inflammation, oxidative stress, endoplasmic reticulum stress, and fibrosis. In addition, the evidence for PPAR-γ- targeted therapy for NAFLD are summarized. Altogether, PPAR-γ is a promising therapeutic target for NAFLD, and the development of drugs that can balance the beneficial and undesirable effects of PPAR-γ will bring new light to NAFLD patients.

Preventive effect of empagliflozin and ezetimibe on hepatic steatosis in adults and murine models

BACKGROUND

Even though many oral glucose-lowering or lipid-lowering agents have already been reported to improve hepatic steatosis to some degree, which drug had a more beneficial effect on hepatic steatosis among those drugs has not been precisely explored. We analysed the effect of empagliflozi, a selective sodium-glucose cotransporter 2 inhibitor, and ezetimibe on developing hepatic steatosis.

METHODS AND RESULTS

Using 4005,779 patients with type 2 diabetes mellitus (T2DM) or dyslipidemia provided by the Korean National Health Insurance Service (NHIS) between January 2015 and December 2015, we analyzed the odds ratio (OR) of fatty liver development (fatty liver index [FLI] >60). Additionally, we examined the metabolic effects of ezetimibe and empagliflozin in mice fed with a choline-deficient high-fat diet, mimicking the features of human NAFLD. The experiment for agents was performed for the non-alcoholic fatty liver (NAFL) and non-alcoholic steatohepatitis (NASH) mouse models independently. In the NHIS data, ORs for the development of fatty liver were significantly lower in all treatment groups than in the reference group, which did not receive ezetimibe or empagliflozin. (Ezetimibe therapy; OR=0.962, empagliflozin therapy; OR=0.527, ezetimibe plus empagliflozin; OR=0.509 compared to reference therapy). Unlike non-alcoholic steatohepatitis mouse model, ezetimibe, empagliflozin, and combination therapy also reduced liver steatosis in the non-alcoholic fatty liver mouse model.

CONCLUSIONS

Compared with other agents, empagliflozin and/or ezetimibe treatment reduced the risk of developing hepatic steatosis. Our data suggest that empagliflozin or ezetimibe can be primarily considered in type 2 DM or dyslipidemia patients to prevent hepatic steatosis.

Natural PPARs agonists for the treatment of nonalcoholic fatty liver disease

Nonalcoholic fatty liver disease (NAFLD) is a general term for a series of liver diseases including simple steatosis, non-alcoholic steatohepatitis, liver fibrosis, which is closely related to metabolic syndrome. The pathogenesis of NAFLD is relatively complex, which has gradually changed from the previous 'two-hit' hypothesis to the current "multiple hits" hypothesis. However, there is currently no approved treatment for NAFLD in clinic, highlighting the urgent need for drug development. Peroxisome proliferator activated receptors (PPARs) are members of the nuclear receptor superfamily, whose different subtypes have been proved to regulate different stages of NAFLD, thus becoming promising drug targets for NAFLD. As important sources of drug development, natural products have been proven to treat NAFLD through multiple pathways and multiple targets. In this paper, we outline the regulatory role of PPARs in NAFLD, and summarize some natural products that target PPARs to ameliorate NAFLD, in order to provide reference for drug development of NAFLD.