Predictors of patient survival following liver transplant in non-alcoholic steatohepatitis: A systematic review and meta-analysis

Resveralogues protect HepG2 cells against cellular senescence induced by hepatotoxic metabolites

Progressive liver disease and dysfunction cause toxic metabolites including ammonia and unconjugated bilirubin to accumulate in plasma. As the population ages alternatives to liver transplantation become increasingly important. One approach for use as a bridge to transplant or recovery is the use of bioartificial liver systems (BALS) containing primary or immortalised hepatocytes as ex-vivo replacements or supports for endogenous liver function. However, exposure to the hepatotoxic metabolites present in plasma causes the rapid failure of these cells to carry out their primary metabolic functions despite remaining viable. Hypothesizing that this loss of core hepatocyte phenotypes was caused by cell senescence we exposed HepG2 cell populations, grown in both standard two-dimensional tissue culture systems and in three dimensional cultures on novel alginate modified HEMA-MBA cryogels, to physiologically reflective concentrations of hepatotoxic metabolites and cytokines. HepG2 cells are forced into senescence by the toxic metabolites in under six hours (as measured by loss of thymidine analog incorporation or detectable Ki67 staining) which is associated with a ten to twenty-fold reduction in the capacity of the cultures to synthesise albumin or urea. This state of senescence induced by liver toxins (SILT) can be prevented by preincubation with either 2-5 µM resveratrol, its major in vivo metabolite dihydroresveratrol or a series of novel resveralogues with differential capacities to scavenge radicals and activate SIRT1 (including V29 which does not interact with the protein). SILT appears to be a previously unrecognised barrier to the development of BALS which can now be overcome using small molecules that are safe for human use at concentrations readily achievable in vivo.

The changing epidemiology of adult liver transplantation in the United States in 2013-2022: The dominance of metabolic dysfunction-associated steatotic liver disease and alcohol-associated liver disease

BACKGROUND

The high prevalence of obesity in the United States drives the burden of NASH, recently renamed as metabolic dysfunction-associated steatohepatitis (MASH). We assessed the most recent trends in liver transplantation in the United States.

METHODS

The Scientific Registry of Transplant Recipients (SRTR 2013-2022) was used to select adult (18 years or above) candidates who underwent liver transplant.

RESULTS

There were 116,292 candidates who underwent liver transplant with known etiology of chronic liver disease. In candidates without HCC, the most common etiology was alcohol-associated liver disease (ALD), increasing from 23% (2013) to 48% (2022), followed by NASH/MASH, which increased from 19% to 27%; the rates of viral hepatitis decreased (chronic hepatitis C: 28%-4%; chronic hepatitis B: 1.8%-1.1%) (all trend p<0.01). The proportion of HCC decreased from 25% (2013-2016) to 17% (2021-2022). Among HCC cohort, the proportion of chronic hepatitis C decreased from 60% (2013) to 27% (2022), NASH/MASH increased from 10% to 31%, alcohol-associated liver disease increased from 9% to 24% (trend p<0.0001), and chronic hepatitis B remained stable between 5% and 7% (trend p=0.62). The rapid increase in the proportion of NASH/MASH in HCC continued during the most recent study years [20% (2018), 28% (2020), 31% (2022)]; the trend remained significant after adjustment for age, sex, ethnicity, obesity, and type 2 diabetes.

CONCLUSIONS

Liver transplant etiologies in the United States have changed over the last decade. Alcohol-associated liver disease and NASH/MASH remain the 2 most common indications for transplantation among those without HCC, and NASH/MASH is the most common in patients with HCC.

Should advanced donor age be a deterrent in the utilization of grafts from donation after cardiac death in deceased donor liver transplantation? The Toronto experience

BACKGROUND

Advanced donor age paired with donation after cardiac death (DCD) increases the risk of transplantation, precluding widespread use of grafts from such donors worldwide. Our aim was to analyze outcomes of liver transplantation using grafts from older DCD donors and donation after brain death (DBD) donors.

METHODS

Patients who underwent liver transplantation using grafts from deceased donors between January 2016 and December 2021 were included in the study. Short-and long-term outcomes were analyzed for 4 groups of patients: those who received DCD and DBD grafts from younger (< 50 yr) and older (≥ 50 yr) donors.

RESULTS

Of the 807 patients included in the analysis, 44.7% (n = 361) of grafts were received from older donors, with grafts for older DCD donors comprising 4.7% of the total cohort (n = 38). Patients who received grafts from older donors had a lower incidence of biliary strictures than those who received grafts from younger donors (7.9% v. 20.0% for DCD donation, p = 0.14, and 4.9% v. 6.8% for DBD donation, p = 0.34), with a significantly lower incidence of ischemic-type biliary strictures in patients who received grafts from older versus younger DCD donors (2.6% v. 18.0%, p = 0.04). There was no difference in 1- and 3-year graft survival rates among patients who received grafts from older and younger DCD donors (92.1% v. 90.8% and 80.2% v. 80.9%, respectively) and those who received grafts from older and younger DBD donors (90.1% v. 93.2% and 85.3% v. 84.4%, respectively) (p = 0.85). Pretransplantation admission to the intensive care unit (hazard ratio [HR] 9.041, p < 0.001) and nonalcoholic steatohepatitis (HR 2.197, p = 0.02) were found to significantly affect survival of grafts from older donors.

CONCLUSION

Donor age alone should not be the criterion to determine the acceptability of grafts in liver transplantation. With careful selection criteria, older DCD donors could make a valuable contribution to expanding the liver donor pool, with grafts that produce comparable results to those obtained with standard-criteria grafts.

Transcriptomic changes in liver transplant recipients with non-alcoholic steatohepatitis indicate dysregulation of wound healing

Background

Non-alcoholic steatohepatitis (NASH) has become a leading indication for liver transplantation. However, it often recurs in the graft and can also arise de novo in individuals transplanted for other indications. Post-transplant NASH (PT-NASH) is more aggressive and leads to accelerated fibrosis. The mechanistic basis of PT-NASH has not yet been defined and no specific therapeutic strategies are currently available.

Methods

Here, we profiled the transcriptomes of livers with PT-NASH from liver transplant recipients to identify dysregulated genes, pathways, and molecular interaction networks.

Results

Transcriptomic changes in the PI3K-Akt pathway were observed in association with metabolic alterations in PT-NASH. Other significant changes in gene expression were associated with DNA replication, cell cycle, extracellular matrix organization, and wound healing. A systematic comparison with non-transplant NASH (NT-NASH) liver transcriptomes indicated an increased activation of wound healing and angiogenesis pathways in the post-transplant condition.

Conclusion

Beyond altered lipid metabolism, dysregulation of wound healing and tissue repair mechanisms may contribute to the accelerated development of fibrosis associated with PT-NASH. This presents an attractive therapeutic avenue to explore for PT-NASH to optimize the benefit and survival of the graft.

Liver transplantation for non-alcoholic fatty liver disease: indications and post-transplant management

Non-alcoholic fatty liver disease (NAFLD) is currently the fastest growing indication to liver transplantation (LT) in Western Countries, both for end stage liver disease and hepatocellular carcinoma. NAFLD/non-alcoholic steatohepatitis (NASH) is often expression of a systemic metabolic syndrome; therefore, NAFLD/NASH patients require a multidisciplinary approach for a proper pre-surgical evaluation, which is important to achieve a post-transplant outcome comparable to that of other indications to LT. NAFLD/NASH patients are also at higher risk of post-transplant cardiovascular events, diabetes, dyslipidemia, obesity, renal impairment and recurrent NASH. Lifestyle modifications, included diet and physical activity, are key to improve survival and quality of life after transplantation. A tailored immunosuppressive regimen may be proposed in selected patients. Development of new drugs for the treatment of recurrent NASH is awaited.