To determine the effect of combined serelaxin and rosiglitazone treatment on established hepatic fibrosis.METHODSHepatic fibrosis was induced in mice by carbon tetrachloride administration for 6 wk, or vehicle alone (...To determine the effect of combined serelaxin and rosiglitazone treatment on established hepatic fibrosis.METHODSHepatic fibrosis was induced in mice by carbon tetrachloride administration for 6 wk, or vehicle alone (nonfibrotic mice). For the final 2 wk, mice were treated with rosiglitazone, serelaxin, or both rosiglitazone and serelaxin. Serum liver enzymes and relaxin levels were determined by standard methods. The degree of liver collagen content was determined by histology and immunohistochemistry. Expression of type I collagen was determined by quantitative PCR. Activation of hepatic stellate cells was assessed by alpha-smooth muscle actin (SMA) levels. Liver peroxisome proliferator activated receptor-gamma coactivator 1 alpha (PGC1α) was determined by Western blotting.RESULTSTreatment of mice with CCl<sub>4</sub> resulted in hepatic fibrosis as evidenced by increased liver enzyme levels (ALT and AST), and increased liver collagen and SMA. Monotherapy with either serelaxin or rosiglitazone for 2 wk was generally without effect. In contrast, the combination of serelaxin and rosiglitazone resulted in significantly improved ALT levels (P < 0.05). Total liver collagen content as determined by Sirius red staining revealed that only combination treatment was effective in reducing total liver collagen (P < 0.05). These results were supported by immunohistochemistry for type I collagen, in which only combination treatment reduced fibrillar collagen levels (P < 0.05). The level of hepatic stellate cell activation was modestly, but significantly, reduced by serelaxin treatment alone, but combination treatment resulted in significantly lower SMA levels. Finally, while hepatic fibrosis reduced liver PGC1α levels, the combination of serelaxin and rosiglitazone resulted in restoration of PGC1α protein levels.CONCLUSIONThe combination of serelaxin and rosiglitazone treatment for 2 wk was effective in significantly reducing established hepatic fibrosis, providing a potential new treatment strategy.展开更多
AIM: To investigate the role of key iron-regulatory protein, hepcidin in non-alcoholic fatty liver disease(NAFLD). METHODS: Hepcidin(Hamp1) knockout and floxed control mice were administered a high fat and high sucros...AIM: To investigate the role of key iron-regulatory protein, hepcidin in non-alcoholic fatty liver disease(NAFLD). METHODS: Hepcidin(Hamp1) knockout and floxed control mice were administered a high fat and high sucrose(HFS) or a regular control diet for 3 or 7 mo. Steatosis, triglycerides, fibrosis, protein and gene expression in mice livers were determined by histological and biochemical techniques, western blotting and realtime polymerase chain reaction. RESULTS: Knockout mice exhibited hepatic iron accumulation. Despite similar weight gains, HFS feeding induced hepatomegaly in floxed, but not knockout, mice. The livers of floxed mice exhibited higher levels of steatosis, triglycerides and c-Jun N-terminal kinase(JNK) phosphorylation than knockout mice. In contrast, a significant increase in fibrosis was observed in knockout mice livers within 3 mo of HFS administration. The hepatic gene expression levels of sterol regulatoryelement-binding protein-1c and fat-specific protein-27, but not peroxisome proliferator-activated receptoralpha or microsomal triglyceride transfer protein, were attenuated in HFS-fed knockout mice. Knockout mice fed with regular diet displayed increased carnitine palmitoyltransferase-1a and phosphoenolpyruvate carboxykinase-1 but decreased glucose-6-phosphatase expression in the liver. In summary, attenuated steatosis correlated with decreased expression of lipogenic and lipid storage genes, and JNK phosphorylation. Deletion of Hamp1 alleles per se modulated hepatic expression of beta-oxidation and gluconeogenic genes. CONCLUSION: Lack of hepcidin expression inhibits hepatic lipid accumulation and induces early development of fibrosis following high fat intake. Hepcidin and iron may play a role in the regulation of metabolic pathways in the liver, which has implications for NAFLD pathogenesis.展开更多
基金Supported by The United States Department of Veterans Affairs Biomedical Laboratory Research and Development Program,No.BX000849National Institutes of Health,NIAAA,No.R01AA015509
文摘To determine the effect of combined serelaxin and rosiglitazone treatment on established hepatic fibrosis.METHODSHepatic fibrosis was induced in mice by carbon tetrachloride administration for 6 wk, or vehicle alone (nonfibrotic mice). For the final 2 wk, mice were treated with rosiglitazone, serelaxin, or both rosiglitazone and serelaxin. Serum liver enzymes and relaxin levels were determined by standard methods. The degree of liver collagen content was determined by histology and immunohistochemistry. Expression of type I collagen was determined by quantitative PCR. Activation of hepatic stellate cells was assessed by alpha-smooth muscle actin (SMA) levels. Liver peroxisome proliferator activated receptor-gamma coactivator 1 alpha (PGC1α) was determined by Western blotting.RESULTSTreatment of mice with CCl<sub>4</sub> resulted in hepatic fibrosis as evidenced by increased liver enzyme levels (ALT and AST), and increased liver collagen and SMA. Monotherapy with either serelaxin or rosiglitazone for 2 wk was generally without effect. In contrast, the combination of serelaxin and rosiglitazone resulted in significantly improved ALT levels (P < 0.05). Total liver collagen content as determined by Sirius red staining revealed that only combination treatment was effective in reducing total liver collagen (P < 0.05). These results were supported by immunohistochemistry for type I collagen, in which only combination treatment reduced fibrillar collagen levels (P < 0.05). The level of hepatic stellate cell activation was modestly, but significantly, reduced by serelaxin treatment alone, but combination treatment resulted in significantly lower SMA levels. Finally, while hepatic fibrosis reduced liver PGC1α levels, the combination of serelaxin and rosiglitazone resulted in restoration of PGC1α protein levels.CONCLUSIONThe combination of serelaxin and rosiglitazone treatment for 2 wk was effective in significantly reducing established hepatic fibrosis, providing a potential new treatment strategy.
基金NIH grant No.R01AA017738(to Harrison-Findik DD)University of Nebraska Medical Center Graduate Assistantship/Fellowship(to Lu S)
文摘AIM: To investigate the role of key iron-regulatory protein, hepcidin in non-alcoholic fatty liver disease(NAFLD). METHODS: Hepcidin(Hamp1) knockout and floxed control mice were administered a high fat and high sucrose(HFS) or a regular control diet for 3 or 7 mo. Steatosis, triglycerides, fibrosis, protein and gene expression in mice livers were determined by histological and biochemical techniques, western blotting and realtime polymerase chain reaction. RESULTS: Knockout mice exhibited hepatic iron accumulation. Despite similar weight gains, HFS feeding induced hepatomegaly in floxed, but not knockout, mice. The livers of floxed mice exhibited higher levels of steatosis, triglycerides and c-Jun N-terminal kinase(JNK) phosphorylation than knockout mice. In contrast, a significant increase in fibrosis was observed in knockout mice livers within 3 mo of HFS administration. The hepatic gene expression levels of sterol regulatoryelement-binding protein-1c and fat-specific protein-27, but not peroxisome proliferator-activated receptoralpha or microsomal triglyceride transfer protein, were attenuated in HFS-fed knockout mice. Knockout mice fed with regular diet displayed increased carnitine palmitoyltransferase-1a and phosphoenolpyruvate carboxykinase-1 but decreased glucose-6-phosphatase expression in the liver. In summary, attenuated steatosis correlated with decreased expression of lipogenic and lipid storage genes, and JNK phosphorylation. Deletion of Hamp1 alleles per se modulated hepatic expression of beta-oxidation and gluconeogenic genes. CONCLUSION: Lack of hepcidin expression inhibits hepatic lipid accumulation and induces early development of fibrosis following high fat intake. Hepcidin and iron may play a role in the regulation of metabolic pathways in the liver, which has implications for NAFLD pathogenesis.
