Therapeutic potential of interleukin-6 in preventing obesity- and alcohol-associated fatty liver transplant failure

Abstract 

Donor organ shortage significantly hinders orthotopic liver transplantation therapy, the only effective treatment for chronic end-stage liver disease and acute liver failure. Further complicating this matter is the prevalence of steatosis in 13% to 50% of donor livers obtained from obese and alcoholic individuals. When transplanted, these livers are associated with primary nonfunction and an elevated risk of dysfunction. New therapeutic approaches to render marginal fatty livers worthy for clinical transplantation are actively being sought. Study findings obtained from my group show that in vitro treatment with interleukin-6 (IL-6) dramatically reduces mortality, liver injury, and necrapoptosis in steatotic Zucker rat liver isografts. Findings of additional studies indicate that IL-6 induces hepatoprotection of steatotic liver isografts by preventing sinusoidal endothelial cell damage and, consequently, the amelioration of hepatic microcirculation, and by protecting against hepatocyte death, which is likely mediated through activation of signal transducer and activator of transcription 3/Bcl-x_L. Finally, in vitro IL-6 treatment also prevents mortality associated with alcoholic fatty liver transplants. Relative to the protective effect of IL-6 on steatotic Zucker rat liver, IL-6 is less effective in alcoholic fatty livers, which may be due to the inhibitory effects of ethanol on IL-6 activation of signal transducer and activator of transcription 3 in hepatocytes and sinusoidal endothelial cells. Collectively, these results support the assertion that in vitro IL-6 treatment of steatotic livers may render allografts usable for clinical transplantation, thereby decreasing the gap between the short supply of cadaver liver allografts and high demands for replacement livers. Higher concentrations of IL-6 may be required to protect against alcoholic fatty liver isograft injury because alcohol inhibits IL-6 signaling in the liver.

Keywords: IL-6, Fatty liver transplantation, Alcohol, STAT3