Study On The Target Of Atorvastatin And Fenofibrate In Alleviating Non-alcoholic Fatty Liver Disease

Objective: Nonalcoholic fatty liver disease(NAFLD)has become the most common liver disease in the world.Although there is no specific drug for the treatment of NAFLD,cholesterol-lowering drug atorvastatin and fatty acid-lowering drug fenofibrate are two types of lipid-lowering drugs commonly used clinically for NAFLD treatment.Recently,studies have found that cholesteryl esters(CE),the combination of cholesterol and fatty acids,play an important role in various diseases.However,it is not clear whether CE are the common therapeutic target of the atorvastatin and fenofibrate during the treatment of NAFLD.Therefore,this study intends to explore whether atorvastatin or fenofibrate ameliorated NAFLD mainly via inhibiting CE formation.Methods:(1)To investigate whether CE levels show significant changes in human patients with NAFLD,blood samples were collected from people with or without non-alcoholic fatty liver disease.GC-MS assay was used to detect the content of CE.The content of CEs was analyzed by LC-MS.(2)To determine the therapeutic effects of atorvastatin or fenofibrate on HFD-induced NAFLD mice,mice were fed either a 60% kcal high-fat diet(HFD)or a normal diet(ND)for 13 weeks.Twenty-six mice were divided into normal diet(ND,n=5),high-fat diet group(HFD,n=7),atorvastatin-treated group(HFD-Ator,20 mg/kg,n=7),and fenofibrate-treated group(HFD-Feno,100 mg/kg,n=7).Mice were injected with a vehicle or drug every other day for 10 weeks.Glucose tolerance(GTT),insulin sensitivity test(ITT)and metabolic cage experiments were performed.After 10 weeks of treatment,mice were anesthetized via an intraperitoneal injection with 10% chloral hydrate(350mg/kg),followed by eyeball extirpation to collect blood.Liver and other tissues were stored at-80℃.(3)In order to verify whether CE are the main target of two drugs during the treatment of NAFLD,the study used the same modeling method.Thirty-five mice were divided into HFD(n=7),HFD-Ator(n=7),HFD-Feno(n=7),atorvastatin-treated group with CE diet(HFD-1%CE-Ator,n=7)and fenofibrate-treated group with CE diet(HFD-1%CE-Feno,n=7).The mice were injected with a vehicle or drug every other day for 10 weeks.The experiment content and execution method of each group of mice are the same as above.(4)To explore the mechanism of the two drugs affecting CE,the study performed quantitative real-time PCR(q PCR)and transcriptomics experiments,and used 16 S r RNA sequencing technology and fecal microbiota transplantation(FMT)experiments to explore whether the drugs affect liver CE levels through gut microbiota(GM).Results:(1)NAFLD patients displayed significantly increased levels of plasma CE compared with the normal control group.(2)Two lipid-lowering drugs could alleviate NAFLD mice and significantly reduced CE levels.(3)CE supplementation weakened the therapeutic effects of two drugs on NAFLD and increased the expression of diacylglycerol acyltransferase 2(Dgat2).(4)Drugs affected CE content through different mechanisms.Fenofibrate reduced CE content and relieved NAFLD through affecting CE synthase.Atorvastatin exerted efficacy by affecting GM to reduce CE content.Conclusions:(1)CE are the main target of atorvastatin and fenofibrate during the treatment of NAFLD.(2)Atorvastatin and fenofibrate affect CE metabolism through different mechanisms.(3)Appropriate reduction of CE intake in the diet may improve the efficacy of lipid-lowering drugs on NAFLD.