Glial Cell Line-Derived Neurotrophic Factor induced Mice Liver Defatting: A Novel Strategy to Enable Transplantation of Steatotic Livers

Abstract

Moderate macrovesicular steatosis (>30%), which is present in almost 50% of livers considered for transplantation increases the risk of primary graft dysfunction. Our previously published data showed that glial cell line-derived neurotrophic factor (GDNF) is protective against high-fat diet (HFD)-induced hepatic steatosis in mice. Hence, we hypothesized that perfusion of steatotic livers with GDNF may reduce liver fat content prior to transplantation. Livers from 8 weeks regular diet (RD) and HFD-fed mice were perfused ex-vivo for 4 hours with either vehicle, GDNF, or a previously described defatting cocktail. Liver’s residual fat was quantified colorimetrically using a triglyceride assay kit, and by Oil Red-O and Nile Red/Hoechst staining. Liver tissue injury was assessed using an LDH activity assay. In vitro induction of lipolysis in HepG2 cells was assessed by measuring glycerol and free fatty acid release. Oil Red-O staining showed significantly more steatosis in liver from HFD-fed mice compared with RD-fed mice (P<0.001). HFD Livers perfused with GDNF had significantly less steatosis than those not perfused (P=0.001) or perfused with vehicle (P<0.05). GDNF is equally effective in steatotic liver defatting compared to the defatting cocktail; however, GDNF induces less liver damage than the defatting cocktail. These observations were consistent with data obtained from assessment of liver triglyceride content. Assessment of liver injury revealed significant hepatocyte injury in livers perfused with the control defatting cocktail but no evidence of injury in livers perfused with either GDNF or vehicle. In vitro, GDNF reduced triglyceride accumulation in HepG2 cells and stimulated increased triglyceride lipolysis.

Conclusion

GDNF can decrease mice liver fat content to an acceptable range and could be a potential defatting agent prior to liver transplantation.