ABSTRACT
BACKGROUND & AIMS: Non-alcoholic fatty liver disease (NAFLD) has emerged as a major liver disease increasingly in association with non-alcoholic steatohepatitis (NASH), cirrhosis and hepatocellular carcinoma (HCC). However, there are currently no approved therapies for treating NAFLD and NASH. Fibroblast growth factor 4 (FGF4) has recently been shown as a promising drug candidate for several metabolic diseases. METHODS: Mice fed a high-fat diet with high fructose/glucose drinking water (HF/HFG, Western-like diet) for 21 weeks were intraperitoneally injected with non-mitogenic recombinant FGF4â³NT (rFGF4â³NT, 1.0 mg/kg body weight) every other day for 8 weeks. Primary mouse hepatocytes cultured in medium containing high glucose/palmitic acid (HG/PA) or TNFα/cyclohexane (TNFα/CHX) were treated with 1.0 µg/ml rFGF4â³NT. Changes in parameters for histopathology, lipid metabolism, inflammation, hepatocellular apoptosis and fibrosis were determined. The Caspase6 activity and AMPK pathway were assessed. RESULTS: Administration of rFGF4â³NT significantly attenuated the Western-like diet-induced hepatic steatosis, inflammation, liver injury and fibrosis in mice. rFGF4â³NT treatment reduced fatty acid-induced lipid accumulation and lipotoxicity-induced hepatocyte apoptosis, which were associated with inhibition of Caspase6 cleavage and activation. Inhibition of AMP-activated protein kinase (AMPK) by Compound C or deficiency of Ampk abrogated rFGF4â³NT-induced hepatoprotection in primary hepatocytes and in mice with NASH. CONCLUSION: rFGF4â³NT exerts significant protective effects on NASH via an AMPK-dependent signaling pathway. Our study indicates that FGF4 analogs may have therapeutic potential for the Western-like diet induced NASH.
Subject(s)
Carcinoma, Hepatocellular , Drinking Water , Liver Neoplasms , Non-alcoholic Fatty Liver Disease , AMP-Activated Protein Kinases , Animals , Cyclohexanes/adverse effects , Drinking Water/adverse effects , Fatty Acids , Fibroblast Growth Factor 4/adverse effects , Fructose/adverse effects , Glucose/adverse effects , Inflammation , Liver Cirrhosis/chemically induced , Liver Cirrhosis/drug therapy , Liver Cirrhosis/pathology , Mice , Mice, Inbred C57BL , Non-alcoholic Fatty Liver Disease/pathology , Palmitic Acid/pharmacology , Tumor Necrosis Factor-alpha/adverse effectsABSTRACT
We evaluated the mitigating effects of fibroblast growth factor 4 and 7 (FGF4 and FGF7, respectively) in comparison with long acting protected graft copolymer (PGC)-formulated FGF4 and 7 (PF4 and PF7, respectively) administered to C57BL/6J mice a day after exposure to LD50/30 (15.7 Gy) partial body irradiation (PBI) which targeted the gastrointestinal (GI) system. The PGC that we developed increased the bioavailability of FGF4 and FGF7 by 5- and 250-fold compared to without PGC, respectively, and also sustained a 24 hr presence in the blood after a single subcutaneous administration. The dose levels tested for mitigating effects on radiation injury were 3 mg/kg for the PF4 and PF7 and 1.5 mg each for their combination (PF4/7). Amifostine administered prior to PBI was used as a positive control. The PF4, PF7, or PF4/7 mitigated the radiation lethality in mice. The mitigating effect of PF4 and PF7 was similar to the positive control and PF7 was better than other mitigators tested. The plasma citrulline levels and hematology parameters were early markers of recovery and survival. GI permeability function appeared to be a late or full recovery indicator. The villus length and crypt number correlated with plasma citrulline level, indicating that it can act as a surrogate marker for these histology evaluations. The IL-18 concentrations in jejunum as early as day 4 and TPO levels in colon on day 10 following PBI showed statistically significant changes in irradiated versus non-irradiated mice which makes them potential biomarkers of radiation exposure. Other colon and jejunum cytokine levels are potentially useful but require larger numbers of samples than in the present study before their full utility can be realized.
Subject(s)
Acute Radiation Syndrome/drug therapy , Fibroblast Growth Factors/therapeutic use , Gastrointestinal Tract/drug effects , Radiation Injuries, Experimental/therapy , Animals , Cell Proliferation/drug effects , Drug Delivery Systems/methods , Female , Fibroblast Growth Factor 4/adverse effects , Fibroblast Growth Factor 4/therapeutic use , Fibroblast Growth Factor 7/adverse effects , Fibroblast Growth Factor 7/therapeutic use , Fibroblast Growth Factors/adverse effects , Fibroblasts/drug effects , Gastrointestinal Tract/pathology , Gastrointestinal Tract/radiation effects , Kaplan-Meier Estimate , Lethal Dose 50 , Male , Mice, Inbred C57BL , Polylysine/chemistry , Polymers/chemistryABSTRACT
Alferminogene tadenovec is a replication-deficient human adenovirus serotype 5 that encodes human FGF4, an angiogenic protein that enhances the formation of new blood vessels. Following early clinical development by Collateral Therapeutics Inc (now Bayer Schering Pharma AG), Cardium Therapeutics Inc is currently developing alferminogene tadenovec as a potential gene therapy to improve the reperfusion of ischemic myocardium. In phase I and II clinical trials, the administration of alferminogene tadenovec was well tolerated and resulted in significant improvements in treadmill exercise capacity. However, two phase IIb/III clinical trials for the gene therapy were discontinued before completion because a high placebo response had occurred, and the trial was considered unlikely to demonstrate a benefit under the design employed. A post-hoc subgroup analysis revealed a substantial benefit from the therapy in female patients only. A phase III clinical trial is currently evaluating alferminogene tadenovec as a therapy for myocardial ischemia in women who are not candidates for revascularization. If further investigations confirm the safety and efficacy of the gene therapy, then alferminogene tadenovec may be considered a realistic therapeutic option for myocardial ischemia in selected patient populations.
