The Liver Cirrhosis Network Cohort Study: Cirrhosis Definition, Study Population, and Endpoints.

INTRODUCTION: One of the primary goals of the Liver Cirrhosis Network (LCN) is to develop a cohort study to better understand and predict the risk of hepatic decompensation and other clinical and patient-reported outcomes among patients with Child A cirrhosis. METHODS: The LCN consists of a Scientific Data Coordinating Center and 10 clinical centers whose investigators populate multiple committees. The LCN Definitions and Measurements Committee developed preliminary definitions of cirrhosis and its complications by literature review, expert opinion, and reviewing definition documents developed by other organizations. The Cohort Committee developed the study protocol with the input of the steering committee. RESULTS: The LCN developed a prospective cohort study to describe and predict the rates of incident clinical events pertaining to first decompensation and patient-reported outcomes. The LCN developed a pragmatic definition of compensated cirrhosis incorporating clinical, laboratory, imaging, and histological criteria. Definitions of incident and recompensated ascites, overt hepatic encephalopathy, variceal hemorrhage, bleeding because of portal gastropathy, and hepatocellular carcinoma were also codified. DISCUSSION: The LCN Cohort Study design will inform the natural history of cirrhosis in contemporary patients with compensated cirrhosis. The LCN Definitions and Measures Committee developed criteria for the definition of cirrhosis to standardize entry into this multicenter cohort study and standardized criteria for liver-related outcome measures. This effort has produced definitions intended to be both sensitive and specific as well as easily operationalized by study staff such that outcomes critical to the LCN cohort are identified and reported in an accurate and generalizable fashion. REGISTRATION: NCT05740358.

Racial Disparities in Evidence-Based Management of Metabolic Dysfunction-Associated Steatotic Liver Disease in Patients With Type 2 Diabetes.

OBJECTIVE: To assess frequency of evidence-based management (EBM) of metabolic dysfunction-associated steatotic liver disease (MASLD) in patients with type 2 diabetes (T2D), and to examine for racial/ethnic disparities in the receipt of EBM. METHODS: We conducted a cross-sectional analysis of patients with T2D and presumptive MASLD in an academic health care system between 2019 and 2021. Presumptive MASLD was defined as at least 1 alanine aminotransferase value ≥30 U/L with exclusions for alcohol overuse, viral hepatitis, liver transplantation, chemotherapy use, and liver disease other than MASLD. We calculated the proportion of patients receiving EBM, defined as a composite of liver ultrasound, transient elastography, or hepatology evaluation. We also examined the association between race/ethnicity and EBM via a logistic regression model. RESULTS: Our sample included 6532 patients; mean age was 58.0 (SD 13.1), 41.7% were female and 3.9%, 26.6%, 58.7%, and 5.8% were of Latino/a/x ethnicity, non-Latino (NL) Black race, NL White race, and NL Asian race, respectively. Rates of EBM were low overall (11.5%), with lower odds of EBM in NL Black versus NL White patients (adjusted odds ratio 0.75; 95% confidence interval 0.59, 0.96). Odds of hepatology evaluation and placement of MASLD diagnosis codes were also lower in NL Black versus NL White patients. CONCLUSION: Racial disparities exist in the receipt of EBM among patients with T2D and presumptive MASLD. These findings highlight the need for research to identify drivers of disparities, and to support development of clinical interventions that equitably facilitate EBM of MASLD in patients with T2D.

MRI Quantification of Placebo Effect in Nonalcoholic Steatohepatitis Clinical Trials.

Background Several early-phase clinical trials for the treatment of nonalcoholic steatohepatitis (NASH) use liver fat content as measured with the MRI-derived proton density fat fraction (PDFF) for a primary outcome. These trials have shown relative reductions in liver fat content with placebo treatment alone, a phenomenon termed "the placebo effect." This phenomenon confounds the results and limits generalizability to future trials. Purpose To quantify the effect of placebo treatment on change in the absolute PDFF value and to identify variables associated with this observed change. Materials and Methods This is a secondary analysis of prospectively collected data from seven early phase clinical trials that included participants with a diagnosis of NASH based on MRI and/or liver biopsy who received placebo treatment. The primary outcome was a greater than or equal to 30% relative reduction in PDFF after placebo treatment. Normalization of PDFF, relative change in alanine aminotransferase (ALT) level, and normalization of ALT level were also examined. An exploratory linear mixed-effects model was used to estimate an overall change in absolute PDFF and to explore parameters associated with this response. Results A total of 187 participants (median age, 52 years [IQR, 43-60 years]; 114 women) who received placebo treatment were evaluated. A greater than or equal to 30% relative reduction in baseline PDFF was seen in 20% of participants after 12 weeks of placebo treatment (10 of 49), 9% of participants after 16 weeks (two of 22), and 28% of participants after 24 weeks (34 of 122). A repeated-measures linear mixed-effects model estimated a decrease of 2.3 units (median relative reduction of 13%) in absolute PDFF values after 24 weeks of placebo treatment (95% CI: 3.2, 1.4; P < .001). Conclusion In this analysis of 187 participants, a clinically relevant decrease in PDFF was observed with placebo treatment. Based on the study model, assuming an absolute PDFF decrease of approximately 3 units (upper limit of 95% CI) to account for this "placebo effect" in sample size calculations for future clinical trials is suggested. Clinical trial registration nos. NCT01066364, NCT01766713, NCT01963845, NCT02443116, NCT02546609, NCT02316717, and NCT02442687 © RSNA, 2022 Online supplemental material is available for this article. See also the editorial by Yoon in this issue.

Glycemic Control Predicts Severity of Hepatocyte Ballooning and Hepatic Fibrosis in Nonalcoholic Fatty Liver Disease.

BACKGROUND AND AIMS: Whether glycemic control, as opposed to diabetes status, is associated with the severity of NAFLD is open for study. We aimed to evaluate whether degree of glycemic control in the years preceding liver biopsy predicts the histological severity of NASH. APPROACH AND RESULTS: Using the Duke NAFLD Clinical Database, we examined patients with biopsy-proven NAFLD/NASH (n = 713) and the association of liver injury with glycemic control as measured by hemoglobin A1c (HbA1c). The study cohort was predominantly female (59%) and White (84%) with median (interquartile range) age of 50 (42, 58) years; 49% had diabetes (n = 348). Generalized linear regression models adjusted for age, sex, race, diabetes, body mass index, and hyperlipidemia were used to assess the association between mean HbA1c over the year preceding liver biopsy and severity of histological features of NAFLD/NASH. Histological features were graded and staged according to the NASH Clinical Research Network system. Group-based trajectory analysis was used to examine patients with at least three HbA1c (n = 298) measures over 5 years preceding clinically indicated liver biopsy. Higher mean HbA1c was associated with higher grade of steatosis and ballooned hepatocytes, but not lobular inflammation. Every 1% increase in mean HbA1c was associated with 15% higher odds of increased fibrosis stage (OR, 1.15; 95% CI, 1.01, 1.31). As compared with good glycemic control, moderate control was significantly associated with increased severity of ballooned hepatocytes (OR, 1.74; 95% CI, 1.01, 3.01; P = 0.048) and hepatic fibrosis (HF; OR, 4.59; 95% CI, 2.33, 9.06; P < 0.01). CONCLUSIONS: Glycemic control predicts severity of ballooned hepatocytes and HF in NAFLD/NASH, and thus optimizing glycemic control may be a means of modifying risk of NASH-related fibrosis progression.

Dysregulation of the ESRP2-NF2-YAP/TAZ axis promotes hepatobiliary carcinogenesis in non-alcoholic fatty liver disease.

BACKGROUND & AIMS: Non-alcoholic fatty liver disease (NAFLD), the hepatic correlate of the metabolic syndrome, is a major risk factor for hepatobiliary cancer (HBC). Although chronic inflammation is thought to be the root cause of all these diseases, the mechanism whereby it promotes HBC in NAFLD remains poorly understood. Herein, we aim to evaluate the hypothesis that inflammation-related dysregulation of the ESRP2-NF2-YAP/TAZ axis promotes HB carcinogenesis. METHODS: We use murine NAFLD models, liver biopsies from patients with NAFLD, human liver cancer registry data, and studies in liver cancer cell lines. RESULTS: Our results confirm the hypothesis that inflammation-related dysregulation of the ESRP2-NF2-YAP/TAZ axis promotes HB carcinogenesis, supporting a model whereby chronic inflammation suppresses hepatocyte expression of ESRP2, an RNA splicing factor that directly targets and activates NF2, a tumor suppressor that is necessary to constrain YAP/TAZ activation. The resultant loss of NF2 function permits sustained YAP/TAZ activity that drives hepatocyte proliferation and de-differentiation. CONCLUSION: Herein, we report on a novel mechanism by which chronic inflammation leads to sustained activation of YAP/TAZ activity; this imposes a selection pressure that favors liver cells with mutations enabling survival during chronic oncogenic stress. LAY SUMMARY: Non-alcoholic fatty liver disease (NAFLD) increases the risk of hepatobiliary carcinogenesis. However, the underlying mechanism remains unknown. Our study demonstrates that chronic inflammation suppresses hepatocyte expression of ESRP2, an adult RNA splicing factor that activates NF2. Thus, inactive (fetal) NF2 loses the ability to activate Hippo kinases, leading to the increased activity of downstream YAP/TAZ and promoting hepatobiliary carcinogenesis in chronically injured livers.

Nonalcoholic Fatty Liver Disease Risk Factors Affect Liver-Related Outcomes After Direct-Acting Antiviral Treatment for Hepatitis C.

INTRODUCTION: In hepatitis C (HCV) patients, obesity and/or diabetes may increase the risk of liver-related outcomes. We aimed to determine whether diabetes and/or obesity are associated with adverse outcomes in direct-acting antiviral (DAA)-treated HCV patients. METHODS: We conducted a retrospective study of 33,003 HCV-infected, DAA-treated Veterans between 2013 and 2015. Body mass index was used to categorize patients into underweight (< 18.5 kg/m2), normal weight (18.5 to < 25 kg/m2), overweight (25 to < 30 kg/m2), obesity I (30 to < 35 kg/m2), and obesity II-III (> 35 kg/m2). Diabetes was defined by ICD-9/10 codes in association with hemoglobin A1c > 6.5% or medication prescriptions. Patients were followed from 180 days post-DAA initiation until 2/14/2019 to assess for development of cirrhosis, decompensations, hepatocellular carcinoma (HCC), and death. Multivariable Cox proportional hazards regression models were used to determine the association between diabetes and/or obesity and outcomes. RESULTS: During a mean follow-up of 3 years, 10.1% patients died, 5.0% were newly diagnosed with cirrhosis, 4.7% had a decompensation and 4.0% developed HCC. Diabetes was associated with an increased risk of mortality (AHR = 1.25, 95% CI 1.10-1.42), cirrhosis (AHR = 1.31, 95% CI 1.16-1.48), decompensation (AHR = 1.74, 95% CI 1.31-2.31), and HCC (AHR = 1.32, 95% CI 1.01-1.72) among patients without baseline cirrhosis. Compared to normal-weight persons, obese persons had a higher risk of cirrhosis, but overweight and obese persons had lower risk of mortality and HCC. CONCLUSIONS: In this large DAA-treated Veterans cohort, pre-DAA diabetes increases mortality and liver-related events independent of SVR. Continued vigilance is warranted in patients with diabetes despite SVR. Elevated BMI categories appear to have improved outcomes, although further studies are needed to understand those associations.

Resmetirom (MGL-3196) for the treatment of non-alcoholic steatohepatitis: a multicentre, randomised, double-blind, placebo-controlled, phase 2 trial.

BACKGROUND: Non-alcoholic steatohepatitis (NASH) is characterised by hepatic steatosis, inflammation, hepatocellular injury, and progressive liver fibrosis. Resmetirom (MGL-3196) is a liver-directed, orally active, selective thyroid hormone receptor-ß agonist designed to improve NASH by increasing hepatic fat metabolism and reducing lipotoxicity. We aimed to assess the safety and efficacy of resmetirom in patients with NASH. METHODS: MGL-3196-05 was a 36-week randomised, double-blind, placebo-controlled study at 25 centres in the USA. Adults with biopsy confirmed NASH (fibrosis stages 1-3) and hepatic fat fraction of at least 10% at baseline when assessed by MRI-proton density fat fraction (MRI-PDFF) were eligible. Patients were randomly assigned 2:1 by a computer-based system to receive resmetirom 80 mg or matching placebo, orally once a day. Serial hepatic fat measurements were obtained at weeks 12 and 36, and a second liver biopsy was obtained at week 36. The primary endpoint was relative change in MRI-PDFF assessed hepatic fat compared with placebo at week 12 in patients who had both a baseline and week 12 MRI-PDFF. This trial is registered with ClinicalTrials.gov, number NCT02912260. FINDINGS: 348 patients were screened and 84 were randomly assigned to resmetirom and 41 to placebo at 18 sites in the USA. Resmetirom-treated patients (n=78) showed a relative reduction of hepatic fat compared with placebo (n=38) at week 12 (-32·9% resmetirom vs -10·4% placebo; least squares mean difference -22·5%, 95% CI -32·9 to -12·2; p<0·0001) and week 36 (-37·3% resmetirom [n=74] vs -8·5 placebo [n=34]; -28·8%, -42·0 to -15·7; p<0·0001). Adverse events were mostly mild or moderate and were balanced between groups, except for a higher incidence of transient mild diarrhoea and nausea with resmetirom. INTERPRETATION: Resmetirom treatment resulted in significant reduction in hepatic fat after 12 weeks and 36 weeks of treatment in patients with NASH. Further studies of resmetirom will allow assessment of safety and effectiveness of resmetirom in a larger number of patients with NASH with the possibility of documenting associations between histological effects and changes in non-invasive markers and imaging. FUNDING: Madrigal Pharmaceuticals.

Association Between Magnetic Resonance Imaging-Proton Density Fat Fraction and Liver Histology Features in Patients With Nonalcoholic Fatty Liver Disease or Nonalcoholic Steatohepatitis.

BACKGROUND & AIMS: Patients with nonalcoholic fatty liver disease (NAFLD) or nonalcoholic steatohepatitis (NASH) often require histologic assessment via liver biopsy. Magnetic resonance imaging (MRI)-based methods for measuring liver triglycerides based on proton density fat fraction (PDFF) are increasingly used as a noninvasive tool to identify patients with hepatic steatosis and to assess for change in liver fat over time. We aimed to determine whether MRI-PDFF accurately reflects a variety of liver histology features in patients with NAFLD or NASH. METHODS: We performed a retrospective analysis of pooled data from 3 phase 2a trials of pharmacotherapies for NAFLD or NASH. We collected baseline clinical, laboratory, and histopathology data on all subjects who had undergone MRI analysis in 1 of the trials. We assessed the relationship between liver PDFF values and liver histologic findings using correlation and area under the receiver operating characteristic (AUROC) analyses. As an ancillary analysis, we also simulated a clinical trial selection process and calculated subject exclusion rates and differences in population characteristics caused by PDFF inclusion thresholds of 6% to 15%. RESULTS: In 370 subjects, the mean baseline PDFF was 17.4% ± 8.6%. Baseline PDFF values correlated with several histopathology parameters, including steatosis grade (r = 0.78; P < .001), NAFLD activity score (NAS, r = 0.54; P < .001), and fibrosis stage (r = -0.59; P < .001). However, PDFF did not accurately identify patients with NAS ≥ 4 (AUROC = 0.72) or fibrosis stage ≥3 (AUROC = 0.66). In a theoretical trial of these subjects, exclusion rates increased as PDFF minimum threshold level increased. There were no significant differences in cohort demographics when PDFF thresholds ranging from 6% to 15% were used, and differences in laboratory and histopathology data were small. CONCLUSIONS: In an analysis of patients with NAFLD or NASH, we determined that although The MRI-PDFF correlated with steatosis grade and NAS, and inversely with fibrosis stage, it was suboptimal in identification of patients with NAS >4 or advanced fibrosis. Although MRI-PDFF is an important imaging biomarker for continued evaluation of this patient population, liver biopsy analysis is still necessary.

Correction to: Identifying Nonalcoholic Fatty Liver Disease Advanced Fibrosis in the Veterans Health Administration.

The original version of the article unfortunately contained errors in Table 3, Risk Factor column headings "Age > 50 (n = 115)," "Age > 50-64 (n = 154)," and "Age > 65 + (n = 60)."

Identifying Nonalcoholic Fatty Liver Disease Advanced Fibrosis in the Veterans Health Administration.

BACKGROUND: Nonalcoholic fatty liver disease (NAFLD) is the most common cause of chronic liver disease. Severe NAFLD with advanced fibrosis results in substantial morbidity and mortality. Associated with metabolic syndrome, NAFLD is often initially clinically silent, yet intensive lifestyle intervention with 7% or greater weight loss can improve or resolve NAFLD. Using a Veterans Health Administration (VHA) liver biopsy cohort, we evaluated simple noninvasive fibrosis scoring systems to identify NAFLD with advanced fibrosis (or severe disease) to assist providers. METHODS: In our retrospective study of a national VHA sample of patients with biopsy-proven NAFLD or normal liver (2005-2015), we segregated patients by fibrosis stage (0-4). Non-NAFLD liver disease was excluded. We evaluated the diagnostic accuracy of the NAFLD fibrosis score (NFS), fibrosis-4 calculator (FIB-4), aspartate aminotransferase-to-alanine aminotransferase ratio (AST/ALT ratio), AST-to-platelet ratio index (APRI), and body mass index, AST/ALT ratio, and diabetes (BARD) score by age groups. RESULTS: We included 329 patients with well-defined liver histology (296 NAFLD and 33 normal controls without fibrosis), in which 92 (28%) had advanced (stage 3-4) fibrosis. Across all age groups, NFS and FIB-4 best predicted advanced fibrosis (NFS with 0.676 threshold: AUROC 0.71-0.76, LR + 2.30-22.05, OR 6.00-39.58; FIB-4 with 2.67 threshold: AUROC of 0.62-0.80, LR + 4.70-27.45, OR 16.34-59.65). CONCLUSIONS: While NFS and FIB-4 scores exhibit good diagnostic accuracy, FIB-4 is optimal in identifying NAFLD advanced fibrosis in the VHA. Easily implemented as a point-of-care clinical test, FIB-4 can be useful in directing patients that are most likely to have advanced fibrosis to GI/hepatology consultation and follow-up.

Systematic transcriptome analysis reveals elevated expression of alcohol-metabolizing genes in NAFLD livers.

Obese animals and non-alcoholic fatty liver disease (NAFLD) patients exhibit elevated blood alcohol, suggesting potential contributions of alcohol metabolism to the development of NAFLD. Liver gene expression in patients with biopsy-proven mild (N = 40) and severe (N = 32) NAFLD were compared to that in healthy liver donors (N = 7) and alcoholic hepatitis (AH; N = 15) using microarrays. Principal components analyses (PCA) revealed similar gene expression patterns between mild and severe NAFLD which clustered with those of AH but were distinct from those of healthy livers. Differential gene expression between NAFLD and healthy livers was consistent with established NAFLD-associated genes and NAFLD pathophysiology. Alcohol-metabolizing enzymes including ADH, ALDH, CYP2E1, and CAT were up-regulated in NAFLD livers. The expression level of alcohol-metabolizing genes in severe NAFLD was similar to that in AH. The NAFLD gene expression profiles provide new directions for future investigations to identify disease markers and targets for prevention and treatment, as well as to foster our understanding of NAFLD pathogenesis and pathophysiology. Particularly, increased expression of alcohol-metabolizing genes in NAFLD livers supports a role for endogenous alcohol metabolism in NAFLD pathology and provides further support for gut microbiome therapy in NAFLD management. Copyright © 2015 Pathological Society of Great Britain and Ireland. Published by John Wiley © Sons, Ltd.

Pleiotrophin regulates the ductular reaction by controlling the migration of cells in liver progenitor niches.

OBJECTIVE: The ductular reaction (DR) involves mobilisation of reactive-appearing duct-like cells (RDC) along canals of Hering, and myofibroblastic (MF) differentiation of hepatic stellate cells (HSC) in the space of Disse. Perivascular cells in stem cell niches produce pleiotrophin (PTN) to inactivate the PTN receptor, protein tyrosine phosphatase receptor zeta-1 (PTPRZ1), thereby augmenting phosphoprotein-dependent signalling. We hypothesised that the DR is regulated by PTN/PTPRZ1 signalling. DESIGN: PTN-GFP, PTN-knockout (KO), PTPRZ1-KO, and wild type (WT) mice were examined before and after bile duct ligation (BDL) for PTN, PTPRZ1 and the DR. RDC and HSC from WT, PTN-KO, and PTPRZ1-KO mice were also treated with PTN to determine effects on downstream signaling phosphoproteins, gene expression, growth, and migration. Liver biopsies from patients with DRs were also interrogated. RESULTS: Although quiescent HSC and RDC lines expressed PTN and PTPRZ1 mRNAs, neither PTN nor PTPRZ1 protein was demonstrated in healthy liver. BDL induced PTN in MF-HSC and increased PTPRZ1 in MF-HSC and RDC. In WT mice, BDL triggered a DR characterised by periportal accumulation of collagen, RDC and MF-HSC. All aspects of this DR were increased in PTN-KO mice and suppressed in PTPRZ1-KO mice. In vitro studies revealed PTN-dependent accumulation of phosphoproteins that control cell-cell adhesion and migration, with resultant inhibition of cell migration. PTPRZ1-positive cells were prominent in the DRs of patients with ductal plate defects and adult cholestatic diseases. CONCLUSIONS: PTN, and its receptor, PTPRZ1, regulate the DR to liver injury by controlling the migration of resident cells in adult liver progenitor niches.

Vitamin D is Not Associated With Severity in NAFLD: Results of a Paired Clinical and Gene Expression Profile Analysis.

OBJECTIVES: The pathogenesis of nonalcoholic fatty liver disease (NAFLD) is complex. Vitamin D (VitD) has been implicated in NAFLD pathogenesis because it has roles in immune modulation, cell differentiation and proliferation, and regulation of inflammation. We evaluated the association of VitD levels, hepatic gene expression for VitD metabolizing genes, and NAFLD histological severity. METHODS: Two adult cohorts, controls (n=39) and NAFLD (n=244), who underwent liver biopsy were compared. Two-sided t-tests or Wilcoxon's rank-sum tests for continuous predictors and chi-squared tests or Fisher's exact tests for categorical variables were used to analyze the association of VitD and NAFLD. Generalized linear models were used to analyze the association of VitD levels and VitD metabolizing genes with histological severity of NAFLD while adjusting for potential confounders and correcting for multiple comparisons. RESULTS: NAFLD patients were more likely than controls to have higher HbA1c (6.5±1.2 vs 5.9±1.0; P=0.009), a risk factor for VitD deficiency. However, no difference in VitD levels was observed between groups. VitD levels did not correlate with the severity of hepatic steatosis, lobular or portal inflammation, or ballooned hepatocytes after adjusting for confounding factors. Furthermore, no association was noted between VitD deficiency or differential expression of genes involved in VitD metabolism and severity of hepatic fibrosis or any other histologic feature of NAFLD. CONCLUSIONS: Neither VitD deficiency, nor hepatic expression of VitD-related genes, associate with the presence or histologic severity of NAFLD in patients. Hence, despite preclinical evidence implicating VitD in NAFLD pathogenesis, VitD deficiency does not appear to be associated with NAFLD severity in humans.

Role of patient factors, preferences, and distrust in health care and access to liver transplantation and organ donation.

Despite major improvements in access to liver transplantation (LT), disparities remain. Little is known about how distrust in medical care, patient preferences, and the origins shaping those preferences contribute to differences surrounding access. We performed a single-center, cross-sectional survey of adults with end-stage liver disease and compared responses between LT listed and nonlisted patients as well as by race. Questionnaires were administered to 109 patients (72 nonlisted; 37 listed) to assess demographics, health care system distrust (HCSD), religiosity, and factors influencing LT and organ donation (OD). We found that neither HCSD nor religiosity explained differences in access to LT in our population. Listed patients attained higher education levels and were more likely to be insured privately. This was also the case for white versus black patients. All patients reported wanting LT if recommended. However, nonlisted patients were significantly less likely to have discussed LT with their physician or to be referred to a transplant center. They were also much less likely to understand the process of LT. Fewer blacks were referred (44.4% versus 69.7%; P = 0.03) or went to the transplant center if referred (44.4% versus 71.1%; P = 0.02). Fewer black patients felt that minorities had as equal access to LT as whites (29.6% versus 57.3%; P < 0.001). For OD, there were more significant differences in preferences by race than listing status. More whites indicated OD status on their driver's license, and more blacks were likely to become an organ donor if approached by someone of the same cultural or ethnic background (P < 0.01). In conclusion, our analysis demonstrates persistent barriers to LT and OD. With improved patient and provider education and communication, many of these disparities could be successfully overcome. Liver Transplantation 22 895-905 2016 AASLD.

Nonalcoholic Fatty Liver Disease: Key Considerations Before and After Liver Transplantation.

Nonalcoholic fatty liver disease (NAFLD) is the most common etiology of chronic liver disease in developed countries and is on trajectory to become the leading indication for liver transplantation in the USA and much of the world. Patients with NAFLD cirrhosis awaiting liver transplant face unique challenges and increased risk for waiting list stagnation and dropout due to burdensome comorbidities including obesity, diabetes, cardiovascular disease, and kidney disease. Thus far, patients transplanted for NAFLD cirrhosis have excellent mid- and long-term patient and graft survival, but concerns regarding short-term morbidity and mortality continue to exist. Post-liver transplantation, NAFLD occurs as both a recurrent and de novo manifestation, each with unique outcomes. NAFLD in the donor population is of concern given the growing demand for liver transplantation and mounting pressure to expand the donor pool. This review addresses key issues surrounding NAFLD as an indication for transplantation, including its increasing prevalence, unique patient demographics, outcomes related to liver transplantation, development of post-liver transplantation NAFLD, and NAFLD in the liver donor population. It also highlights exciting areas where further research is needed, such as the role of bariatric surgery and preconditioning of marginal donor grafts.

Vitamin B5 and N-Acetylcysteine in Nonalcoholic Steatohepatitis: A Preclinical Study in a Dietary Mouse Model.

BACKGROUND: Nonalcoholic fatty liver disease (NAFLD) is the number one cause of chronic liver disease and second indication for liver transplantation in the Western world. Effective therapy is still not available. Previously we showed a critical role for caspase-2 in the pathogenesis of nonalcoholic steatohepatitis (NASH), the potentially progressive form of NAFLD. An imbalance between free coenzyme A (CoA) and acyl-CoA ratio is known to induce caspase-2 activation. OBJECTIVES: We aimed to evaluate CoA metabolism and the effects of supplementation with CoA precursors, pantothenate and cysteine, in mouse models of NASH. METHODS: CoA metabolism was evaluated in methionine-choline deficient (MCD) and Western diet mouse models of NASH. MCD diet-fed mice were treated with pantothenate and N-acetylcysteine or placebo to determine effects on NASH. RESULTS: Liver free CoA content was reduced, pantothenate kinase (PANK), the rate-limiting enzyme in the CoA biosynthesis pathway, was down-regulated, and CoA degrading enzymes were increased in mice with NASH. Decreased hepatic free CoA content was associated with increased caspase-2 activity and correlated with worse liver cell apoptosis, inflammation, and fibrosis. Treatment with pantothenate and N-acetylcysteine did not inhibit caspase-2 activation, improve NASH, normalize PANK expression, or restore free CoA levels in MCD diet-fed mice. CONCLUSION: In mice with NASH, hepatic CoA metabolism is impaired, leading to decreased free CoA content, activation of caspase-2, and increased liver cell apoptosis. Dietary supplementation with CoA precursors did not restore CoA levels or improve NASH, suggesting that alternative approaches are necessary to normalize free CoA during NASH.

Hepatic gene expression profiles differentiate presymptomatic patients with mild versus severe nonalcoholic fatty liver disease.

UNLABELLED: Clinicians rely upon the severity of liver fibrosis to segregate patients with well-compensated nonalcoholic fatty liver disease (NAFLD) into subpopulations at high- versus low-risk for eventual liver-related morbidity and mortality. We compared hepatic gene expression profiles in high- and low-risk NAFLD patients to identify processes that distinguish the two groups and hence might be novel biomarkers or treatment targets. Microarray analysis was used to characterize gene expression in percutaneous liver biopsies from low-risk, "mild" NAFLD patients (fibrosis stage 0-1; n = 40) and high-risk, "severe" NAFLD patients (fibrosis stage 3-4; n = 32). Findings were validated in a second, independent cohort and confirmed by real-time polymerase chain reaction and immunohistochemistry (IHC). As a group, patients at risk for bad NAFLD outcomes had significantly worse liver injury and more advanced fibrosis (severe NAFLD) than clinically indistinguishable NAFLD patients with a good prognosis (mild NAFLD). A 64-gene profile reproducibly differentiated severe NAFLD from mild NAFLD, and a 20-gene subset within this profile correlated with NAFLD severity, independent of other factors known to influence NAFLD progression. Multiple genes involved with tissue repair/regeneration and certain metabolism-related genes were induced in severe NAFLD. Ingenuity Pathway Analysis and IHC confirmed deregulation of metabolic and regenerative pathways in severe NAFLD and revealed overlap among the gene expression patterns of severe NAFLD, cardiovascular disease, and cancer. CONCLUSION: By demonstrating specific metabolic and repair pathways that are differentially activated in livers with severe NAFLD, gene profiling identified novel targets that can be exploited to improve diagnosis and treatment of patients who are at greatest risk for NAFLD-related morbidity and mortality.

Relationship between methylome and transcriptome in patients with nonalcoholic fatty liver disease.

BACKGROUND & AIMS: Cirrhosis and liver cancer are potential outcomes of advanced nonalcoholic fatty liver disease (NAFLD). It is not clear what factors determine whether patients will develop advanced or mild NAFLD, limiting noninvasive diagnosis and treatment before clinical sequelae emerge. We investigated whether DNA methylation profiles can distinguish patients with mild disease from those with advanced NAFLD, and how these patterns are functionally related to hepatic gene expression. METHODS: We collected frozen liver biopsies and clinical data from patients with biopsy-proven NAFLD (56 in the discovery cohort and 34 in the replication cohort). Samples were divided into groups based on histologic severity of fibrosis: F0-1 (mild) and F3-4 (advanced). DNA methylation profiles were determined and coupled with gene expression data from the same biopsies; differential methylation was validated in subsets of the discovery and replication cohorts. We then analyzed interactions between the methylome and transcriptome. RESULTS: Clinical features did not differ between patients known to have mild or advanced fibrosis based on biopsy analysis. There were 69,247 differentially methylated CpG sites (76% hypomethylated, 24% hypermethylated) in patients with advanced vs mild NAFLD (P < .05). Methylation at fibroblast growth factor receptor 2, methionine adenosyl methyltransferase 1A, and caspase 1 was validated by bisulfite pyrosequencing and the findings were reproduced in the replication cohort. Methylation correlated with gene transcript levels for 7% of differentially methylated CpG sites, indicating that differential methylation contributes to differences in expression. In samples with advanced NAFLD, many tissue repair genes were hypomethylated and overexpressed, and genes in certain metabolic pathways, including 1-carbon metabolism, were hypermethylated and underexpressed. CONCLUSIONS: Functionally relevant differences in methylation can distinguish patients with advanced vs mild NAFLD. Altered methylation of genes that regulate processes such as steatohepatitis, fibrosis, and carcinogenesis indicate the role of DNA methylation in progression of NAFLD.