摘要
Non-alcoholic fatty liver disease(NAFLD) is a major health care problem and represents the hepatic expression of the metabolic syndrome. NAFLD is classified as nonalcoholic fatty liver(NAFL) or simple steatosis,and non-alcoholic steatohepatitis(NASH). NASH is characterized by the presence of steatosis and inflammation with or without fibrosis. The physiopathology of NAFL and NASH and their progression to cirrhosis involve several parallel and interrelated mechanisms,such as,insulin resistance(IR),lipotoxicity,inflammation,oxidative stress,and recently the gut-liver axis interaction has been described. Incretin-based therapies could play a role in the treatment of NAFLD. Glucagon-like peptide-1(GLP-1) is an intestinal mucosa-derived hormone which is secreted into the bloodstream in response to nutrient ingestion; it favors glucose-stimulated insulin secretion,inhibition of postprandial glucagon secretion and delayed gastric emptying. It also promotes weight loss and is involved in lipid metabolism. Once secreted,GLP-1 is quickly degraded by dipeptidyl peptidase-4(DPP-4). Therefore,DPP-4 inhibitors are able to extend the activity of GLP-1. Currently,GLP-1 agonists and DPP-4 inhibitors represent attractive options for the treatment of NAFLD and NASH. The modulation of lipid and glucose metabolism through nuclear receptors,such as the farsenoid X receptor,also constitutes an attractive therapeutic target. Obeticholic acid is a potent activator of the farnesoid X nuclear receptor and reduces liver fat content and fibrosis in animal models. Ursodeoxycholic acid(UDCA) is a hydrophilic bile acid with immunomodulatory,antiinflammatory,antiapoptotic,antioxidant and antifibrotic properties. UDCA can improve IR and modulate lipid metabolism through its interaction with nuclear receptors such as,TGR5,farnesoid X receptor-a,or the small heterodimeric partner. Finally,pharmacologic modulation of the gut microbiota could have a role in the therapy of NAFLD and NASH. Probiotics prevent bacterial translocation and epithelial invasion,inhibit mucosal adherence by bacteria,and stimulate host immunity. In animal models,probiotics prevent obesity,decrease transaminase levels,and improve IR and liver histology in NASH.
Non-alcoholic fatty liver disease （NAFLD） is a major healthcare problem and represents the hepatic expression ofthe metabolic syndrome. NAFLD is classified as nonalcoholicfatty liver （NAFL） or simple steatosis, and nonalcoholicsteatohepatitis （NASH）. NASH is characterizedby the presence of steatosis and inflammation withor without fibrosis. The physiopathology of NAFL andNASH and their progression to cirrhosis involve severalparallel and interrelated mechanisms, such as, insulinresistance （IR）, lipotoxicity, inflammation, oxidativestress, and recently the gut-liver axis interaction has beendescribed. Incretin-based therapies could play a role inthe treatment of NAFLD. Glucagon-like peptide-1 （GLP-1）is an intestinal mucosa-derived hormone which is secretedinto the bloodstream in response to nutrient ingestion;it favors glucose-stimulated insulin secretion, inhibitionof postprandial glucagon secretion and delayed gastricemptying. It also promotes weight loss and is involvedin lipid metabolism. Once secreted, GLP-1 is quicklydegraded by dipeptidyl peptidase-4 （DPP-4）. Therefore,DPP-4 inhibitors are able to extend the activity of GLP-1.Currently, GLP-1 agonists and DPP-4 inhibitors representattractive options for the treatment of NAFLD andNASH. The modulation of lipid and glucose metabolismthrough nuclear receptors, such as the farsenoid Xreceptor, also constitutes an attractive therapeutic target.Obeticholic acid is a potent activator of the farnesoidX nuclear receptor and reduces liver fat content andfibrosis in animal models. Ursodeoxycholic acid （UDCA）is a hydrophilic bile acid with immunomodulatory, antiinflammatory,antiapoptotic, antioxidant and antifibroticproperties. UDCA can improve IR and modulatelipid metabolism through its interaction with nuclearreceptors such as, TGR5, farnesoid X receptor-a, orthe small heterodimeric partner. Finally, pharmacologicmodulation of the gut microbiota could have a role in thetherapy of NAFLD and NASH. Probiotics prevent bacterialtranslocation and epithelial invasion, inhibit mucosaladherence by bacteria, and stimulate host immunity.In animal models, probiotics prevent obesity, decreasetransaminase levels, and improve IR and liver histology inNASH.
