Harrison, Stephen A.

INTRODUCTION: The recent US Food and Drug Administration approval of resmetirom for treating metabolic dysfunction-associated steatohepatitis in patients necessitates patient selection for significant fibrosis or higher (≥F2). No existing vibration-controlled transient elastography (VCTE) algorithm targets ≥F2. METHODS: The mAchine Learning ADvanceD fibrosis and rIsk metabolic dysfunction-associated steatohepatitis Novel predictor (ALADDIN) study addressed this gap by introducing a machine-learning-based web calculator that estimates the likelihood of significant fibrosis using routine laboratory parameters with and without VCTE. Our study included a training set of 827 patients, a testing set of 504 patients with biopsy-confirmed metabolic dysfunction-associated steatotic liver disease from 6 centers, and an external validation set of 1,299 patients from 9 centers. Five algorithms were compared using area under the curve (AUC) in the test set: ElasticNet, random forest, gradient boosting machines, XGBoost, and neural networks. The top 3 (random forest, gradient boosting machines, and XGBoost) formed an ensemble model. RESULTS: In the external validation set, the ALADDIN-F2-VCTE model, using routine laboratory parameters with VCTE (AUC 0.791, 95% confidence interval [CI]: 0.764–0.819), outperformed VCTE alone (0.745, 95% CI 0.717–0.772, P < 0.0001), FibroScan-aspartate aminotransferase (0.710, 0.679–0.748, P < 0.0001), and Agile-3 model (0.740, 0.710–0.770, P < 0.0001) regarding the AUC, decision curve analysis, and calibration. The ALADDIN-F2-Lab model, using routine laboratory parameters without VCTE, achieved an AUC of 0.706 (95% CI: 0.668–0.749) and outperformed Fibrosis-4, steatosis-associated fibrosis estimator, and LiverRisk scores. DISCUSSION: Along with the steatosis-associated fibrosis estimator model developed to target significant fibrosis or higher, ALADDIN-F2-VCTE (https://aihepatology.shinyapps.io/ALADDIN1) uniquely supports a refined noninvasive approach to patient selection for resmetirom without the need for liver biopsy. In addition, ALADDIN-F2-Lab (https://aihepatology.shinyapps.io/ALADDIN2) offers an effective alternative when VCTE is unavailable.

Abstract Despite its considerable and growing burden, there are currently no Food and Drug Administration‐approved treatments for metabolic dysfunction‐associated steatotic liver disease or its progressive form, metabolic dysfunction‐associated steatohepatitis (MASH). Several glucagon‐like peptide‐1 receptor agonists (GLP‐1RAs) and other agents are in various phases of clinical development for use in MASH; an ideal therapy should reduce liver fat content, improve chronic liver disease, help mitigate metabolic comorbidities and decrease all‐cause mortality. Because of interconnected disease mechanisms, metabolic dysfunction‐associated steatotic liver disease/MASH often coexists with type 2 diabetes (T2D), obesity and cardiovascular disease. Various GLP‐1RAs are Food and Drug Administration‐approved for use in T2D, and two, liraglutide and semaglutide, are approved for overweight and obesity. GLP‐1RAs decrease glucose levels and body weight and improve cardiovascular outcomes in people with T2D who are at high risk of cardiovascular disease. In addition, GLP‐1RAs have been reported to reduce liver fat content and liver enzymes, reduce oxidative stress and improve hepatic de novo lipogenesis and the histopathology of MASH. Weight loss may contribute to these effects; however, the exact mechanisms are unknown. Adverse events that are commonly associated with GLP‐1RAs include vomiting, nausea and diarrhoea. There is a lack of evidence from meta‐analyses regarding the increased risk of acute pancreatitis and various forms of cancer with GLP‐1RAs. Large‐scale, phase 3 trials, which will provide definitive data on GLP‐1RAs and other potential therapies in MASH, are ongoing. Given the spectrum of modalities under investigation, it is hoped that these trials will support the identification of pharmacotherapies that provide clinical benefit for patients with MASH.

Background and Aims: Aldafermin, an engineered analog of the human hormone FGF19, improves liver histology in patients with noncirrhotic NASH; however, its efficacy and safety in compensated cirrhosis is unknown. No drug has yet to demonstrate benefit in the compensated NASH population. Approach and Results: In this multicenter, double-blind, placebo-controlled, phase 2b trial, 160 patients with compensated NASH cirrhosis were randomized to aldafermin 0.3 mg (n = 7), 1 mg (n = 42), 3 mg (n = 55), or placebo (n = 56) for 48 weeks. The 0.3 mg group was discontinued to limit exposure to suboptimal doses. The primary end point was a change in Enhanced Liver Fibrosis from baseline to week 48. The analyses were performed in the intention-to-treat population. At week 48, the least-squares mean difference in the change in Enhanced Liver Fibrosis was −0.5 (95% CI, −0.7 to −0.2; p = 0.0003) between the 3 mg group and the placebo group. 15%, 21%, and 23% of patients in the placebo, 1 mg, and 3 mg group, respectively, achieved fibrosis improvement ≥ 1 stage; and 13%, 16%, and 20% achieved fibrosis improvement ≥ 1 stage without NASH worsening. Improvement in alanine aminotransferase, aspartate aminotransferase, neoepitope-specific N-terminal pro-peptide of type III collagen, and liver stiffness favored aldefermin groups over placebo. Diarrhea was the most frequent adverse event, occurring at 26% and 40% in the 1 mg and 3 mg groups, respectively, compared to 18% in the placebo group. Overall, 0%, 2%, and 9% of patients in the placebo, 1 mg, and 3 mg group, respectively, discontinued due to treatment-related adverse events. Conclusions: Aldafermin 3 mg resulted in a significant reduction in Enhanced Liver Fibrosis in patients with compensated NASH cirrhosis.

The principal limitations of the terms NAFLD and NASH are the reliance on exclusionary confounder terms and the use of potentially stigmatising language. This study set out to determine if content experts and patient advocates were in favor of a change in nomenclature and/or definition. A modified Delphi process was led by three large pan-national liver associations. The consensus was defined a priori as a supermajority (67%) vote. An independent committee of experts external to the nomenclature process made the final recommendation on the acronym and its diagnostic criteria. A total of 236 panelists from 56 countries participated in 4 online surveys and 2 hybrid meetings. Response rates across the 4 survey rounds were 87%, 83%, 83%, and 78%, respectively. Seventy-four percent of respondents felt that the current nomenclature was sufficiently flawed to consider a name change. The terms “nonalcoholic” and “fatty” were felt to be stigmatising by 61% and 66% of respondents, respectively. Steatotic liver disease was chosen as an overarching term to encompass the various aetiologies of steatosis. The term steatohepatitis was felt to be an important pathophysiological concept that should be retained. The name chosen to replace NAFLD was metabolic dysfunction–associated steatotic liver disease. There was consensus to change the definition to include the presence of at least 1 of 5 cardiometabolic risk factors. Those with no metabolic parameters and no known cause were deemed to have cryptogenic steatotic liver disease. A new category, outside pure metabolic dysfunction–associated steatotic liver disease, termed metabolic and alcohol related/associated liver disease (MetALD), was selected to describe those with metabolic dysfunction–associated steatotic liver disease, who consume greater amounts of alcohol per week (140–350 g/wk and 210–420 g/wk for females and males, respectively). The new nomenclature and diagnostic criteria are widely supported and nonstigmatising, and can improve awareness and patient identification.

Abstract Background and Aims The NASH Clinical Research Network histologic scoring system, the gold‐standard NASH histology assessment for clinical trials, has demonstrated intrarater and interrater variability. An expert panel in a previous systematic Research and Development/University of California Los Angeles (RAND/UCLA) study determined that existing histologic scoring systems do not fully capture NASH disease activity and fibrosis, and standardized definitions of histologic features are needed. We evaluated the reliability of existing and alternate histologic measures and their correlations with a disease activity visual analog scale to propose optimal components for an expanded NAFLD activity score (NAS). Approach and Results Four liver pathologists who were involved in the prior RAND/UCLA study underwent standardized training and multiple discussions with the goal of improving agreement. They were blinded to clinical information and scored histologic measures twice, ≥2 weeks apart, for 40 liver biopsies representing the full spectrum of NAFLD. Index intraclass correlation coefficient (ICC) estimates demonstrated intrarater (0.80–0.85) and interrater (0.60–0.72) reliability. Hepatocyte ballooning items had similar interrater ICCs (0.68–0.79), including those extending scores from 0–2 to 0–4. Steatosis measures (interrater ICCs, 0.72–0.80) correlated poorly with disease activity. Correlations with disease activity were largest for hepatocyte ballooning and Mallory‐Denk bodies (MDBs), with both used to develop the expanded NAS (intrarater ICC, 0.90; interrater ICC, 0.80). Fibrosis measures had ICCs of 0.70–0.87. Conclusions After extensive preparation among a group of experienced pathologists, we demonstrated improved reliability of multiple existing histologic NAFLD indices and fibrosis staging systems. Hepatocyte ballooning and MDBs most strongly correlated with disease activity and were used for the expanded NAS. Further validation including evaluation of responsiveness is required.

Nonalcoholic fatty liver disease (NAFLD) is currently one of most common forms of chronic liver disease globally. NAFLD represents a wide spectrum of liver involvement from nonprogressive isolated steatosis to nonalcoholic steatohepatitis (NASH), characterized by liver necroinflammation and fibrosis and currently one of the top causes of end‐stage liver disease and hepatocellular carcinoma. At present, there is a lack of effective treatments, and a central barrier to the development of therapies is the requirement for an invasive liver biopsy for diagnosis of NASH. Discovery of reliable, noninvasive biomarkers are urgently needed. In this study, we tested whether circulating extracellular vesicles (EVs), cell‐derived small membrane‐surrounded structures with a rich cargo of bioactive molecules, may serve as reliable noninvasive “liquid biopsies” for NASH diagnosis and assessment of disease severity. Total circulating EVs and hepatocyte‐derived EVs were isolated by differential centrifugation and size‐exclusion chromatography from serum samples of healthy individuals, patients with precirrhotic NASH, and patients with cirrhotic NASH. EVs were further characterized by flow cytometry, electron microscopy, western blotting, and dynamic light scattering assays before performing a proteomics analysis. Our findings suggest that levels of total and hepatocyte‐derived EVs correlate with NASH clinical characteristics and disease severity. Additionally, using proteomics data, we developed understandable, powerful, and unique EV‐based proteomic signatures for potential diagnosis of advanced NASH. Conclusion: Our study shows that the quantity and protein constituents of circulating EVs provide strong evidence for EV protein–based liquid biopsies for NAFLD/NASH diagnosis.

Mixed lineage kinase 3 (MLK3) deficiency reduces macrophage‐associated inflammation in a murine model of nonalcoholic steatohepatitis (NASH). However, the mechanistic links between MLK3 activation in hepatocytes and macrophage‐driven inflammation in NASH are uncharted. Herein, we report that MLK3 mediates the release of (C‐X‐C motif) ligand 10 (CXCL10)‐laden extracellular vesicles (EVs) from lipotoxic hepatocytes, which induce macrophage chemotaxis. Primary mouse hepatocytes (PMHs) and Huh7 cells were treated with palmitate or lysophosphatidylcholine (LPC). Released EVs were isolated by differential ultracentrifugation. LPC treatment of PMH or Huh7 cells induced release of EVs, which was prevented by either genetic or pharmacological inhibition of MLK3. Mass spectrometry identified the potent chemokine, CXCL10, in the EVs, which was markedly enriched in EVs isolated from LPC‐treated hepatocytes versus untreated cells. Green fluorescent protein (GFP)‐tagged CXCL10 was present in vesicular structures and colocalized with the red fluorescent protein (RFP)‐tagged EV marker, CD63, after LPC treatment of cotransfected Huh‐7 cells. Either genetic deletion or pharmacological inhibition of MLK3 prevented CXCL10 enrichment in EVs. Treatment of mouse bone‐marrow–derived macrophages with lipotoxic hepatocyte‐derived EVs induced macrophage chemotaxis, an effect blocked by incubation with CXCL10‐neutralizing antisera. MLK3‐deficient mice fed a NASH‐inducing diet had reduced concentrations of total plasma EVs and CXCL10 containing EVs compared to wild‐type mice. Conclusions: During hepatocyte lipotoxicity, activated MLK3 induces the release of CXCL10‐bearing vesicles from hepatocytes, which are chemotactic for macrophages. (Hepatology 2016;63:731–744)