Autoimmune hepatitis-primary biliary cirrhosis concurrent with biliary stricture after liver transplantation

Although the development of de novo autoimmune liver disease after liver transplantation (LT) has been described in both children and adults, autoimmune hepatitis (AIH)-primary biliary cirrhosis (PBC) overlap syndrome has rarely been seen in liver transplant recipients. Here, we report a 50-year-old man who underwent LT for decompensated liver disease secondary to alcoholic steatohepatitis. His liver function tests became markedly abnormal 8 years after LT. Standard autoimmune serological tests were positive for anti-nuclear and anti-mitochondrial antibodies, and a marked biochemical response was observed to a regimen consisting of prednisone and ursodeoxycholic acid added to maintain immunosuppressant tacrolimus. Liver biopsy showed moderate bile duct lesions and periportal lymphocytes infiltrating along with light fibrosis, which confirmed the diagnosis of AIH-PBC overlap syndrome. We believe that this may be a case of post-LT de novo AIH-PBC overlap syndrome; a novel type of autoimmune overlap syndrome.

Micro- and macrovesicular steatotic liver model for transplantation induced by ethanol and protein-deficient diet

Steatotic liver grafts are associated with a high incidence of primary nonfunction and initial poor function. Due to the increasing number of liver transplant candidates, centers are inclined to accept marginal donors more frequently. For a lack of a reliable fatty liver model, preservation concepts for fatty livers have hardly been evaluated. Moreover, there is an ongoing debate on the relevance and impact of micro- versus macrovesicular steatotic organs. We therefore intended to establish a steatotic liver model in pigs comprising both micro- and macrovesicular steatotic livers. Five groups of pigs received daily 1 to 6 g ethanol/kg body weight and/or a protein-deficient diet for up to 72 days. Liver biopsy was carried out at days 24, 48, and 72. With an increasing amount and duration of ethanol intake, higher levels of microvesicular steatosis were induced. Ethanol and protein deficient diet resulted in more than 60% microvesicular steatosis after 72 days. Exclusively protein-deficient diet without ethanol induced macrovesicular steatosis of more than 70% after 72 days. For the first time, we established a porcine model of hepatic steatosis that comprises both histologic types of fatty liver: micro- and macrovesicular steatosis induced by ethanol and a protein-deficient diet. We would like to conclude that our model is particularly qualified to study new concepts of preservation for steatotic livers to improve on the posttransplant outcome.

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

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.

Role of free radicals in failure of fatty liver grafts caused by ethanol

Alcohol is associated with accidental deaths and suicides leading to organ donation, and hepatic steatosis is an important risk factor for initial poor function and failure of human liver grafts. Mechanisms of fatty graft failure are not fully understood, but increased oxidative stress may be a major factor. To characterize the role of free radical stress and the efficacy of antioxidant treatments in fatty liver graft injury, donors for orthotopic rat liver transplantation were treated chronically (3 or more weeks) and acutely (single dose) with ethanol. After transplantation, necrosis and alanine aminotransferase release were threefold to fourfold higher in recipients of fatty grafts from donors treated with ethanol either acutely or chronically compared with findings for recipients of grafts from untreated donors. Moreover, graft survival decreased from nearly 100% to less than 20%. Free radical adducts, as measured by electron spin resonance spectroscopy, were detected in the blood and bile of rats receiving fatty grafts caused by ethanol. Markers of lipid peroxidation also increased after transplantation. Destruction of Kupffer cells with gadolinium chloride decreased free radical production and improved graft survival. Leukocyte adhesion increased beginning early after implantation, and adherent white blood cells obtained from transplanted fatty livers produced the same free radical species as were detected in blood. Therefore, Kupffer cells and adherent white blood cells are important sources of free radicals. Free radicals not only damage fatty grafts directly but also lead to enhanced inflammation and disturbed microcirculation. Delivery of superoxide dismutase-1 and superoxide dismutase-2 genes, free radical-scavenging polyphenols, and antioxidant-containing Carolina Rinse solution reduced injury and improved survival of fatty grafts caused by ethanol. Taken together, these findings indicate that free radicals increase in fatty grafts after transplantation and play an important role in injury of fatty grafts obtained from ethanol-exposed donors. Treatment of fatty donor livers with antioxidants and free radical scavengers may thus be an effective clinical therapy to prevent failure of fatty grafts.

In vitro interleukin-6 treatment prevents mortality associated with fatty liver transplants in rats

BACKGROUND & AIMS

Orthotopic liver transplantation is currently the only curative therapy for chronic end-stage liver disease and acute liver failure. However, a scarcity of cadaveric donors has led to a critical shortage of organs available for transplant. This is further complicated by the prevalence of steatosis in about 13%-50% of donor livers, which is associated with a high risk of dysfunction and primary nonfunction.

METHODS

Steatotic Zucker rat livers and livers from alcohol-fed rats were transplanted into lean control rats. Liver injury, activation of survival signals, and hepatic microcirculation were compared in nontreated and interleukin-6 (IL-6)-treated steatotic isografts.

RESULTS

IL-6 pretreatment of steatotic Zucker rat liver isografts dramatically reduces mortality and liver injury following transplantation. Reperfusion after transplantation induces significant sinusoidal endothelial cell necrapoptosis in steatotic Zucker rat liver isografts, which is prevented by in vitro IL-6 pretreatment. IL-6 treatment activates cell survival signal transducer and activator of transcription factor 3 (STAT3) in hepatocytes and sinusoidal endothelial cells. Laser Doppler imaging and microsphere analyses demonstrate that IL-6 treatment markedly improves hepatic microcirculation, which is impaired in steatotic Zucker rat liver transplants. Finally, in vitro IL-6 treatment of donor livers also markedly reduces mortality associated with fatty liver transplants from alcohol-fed rats.

CONCLUSIONS

IL-6 induces hepatoprotection of steatotic liver isografts via preventing sinusoidal endothelial cell necrapoptosis and consequent amelioration of hepatic microcirculation, and protecting against hepatocyte death. IL-6 pretreatment of steatotic livers may render such allografts useable for clinical transplantation.