Numerous observations have indicated that significant amounts of liver fibrosis can either completely disappear or be substantially remodelled after removal of the initiating agent or following effective therapeutic intervention. Reversal of established cirrhosis has also been documented. Studies of fibrosis regression have largely used semiquantitative staging systems that were developed to assess progressive disease and are limited by their categorical nature. A more nuanced system, the Beijing P-I-R classification, has been validated only in viral liver disease. The clinical significance of regressive features remains largely unstudied. In this brief review, we address shortcomings in (i) the histological assessment of fibrosis regression across the spectrum of common chronic liver diseases and (ii) the identification of a 'point of no return' in advanced fibrosis. We argue that the hepatopathology community should rise to these challenges, perhaps aided by the development of artificial intelligence solutions for the assessment of liver biopsies.

Objective: Metabolic dysfunction-associated steatotic liver disease (MASLD) is the most common chronic liver disease in children and is linked to type 2 diabetes. This study evaluates whether longitudinal changes in liver chemistries—gamma-glutamyl transferase (GGT), aspartate aminotransferase (AST), and alanine aminotransferase (ALT)—can serve as biomarkers of increased type 2 diabetes risk in children with MASLD. Research Design and Methods: This multicenter longitudinal cohort study followed 1,035 children with biopsy-confirmed MASLD, without type 2 diabetes at baseline, for a mean of 3.9 years. Liver chemistries were measured annually, and type 2 diabetes was diagnosed based on fasting glucose, hemoglobin A1c, and clinical diagnosis. Extended Cox models with inverse probability weighting were used to evaluate associations between liver enzyme trajectories and type 2 diabetes risk. Results: The cumulative incidence of type 2 diabetes was 12.3%. Increases in GGT (HR: 1.55, 95% CI: 1.34-1.80), AST (HR: 1.31, 95% CI: 1.20-1.43), and ALT (HR: 1.13, 95% CI: 1.07-1.20) were associated with a higher risk of developing type 2 diabetes in the independent models. In the mutual model with all three liver chemistries, only GGT and AST remained significant. Conclusions: A 30-unit increase in GGT over time was associated with a substantially higher risk of developing type 2 diabetes in children with MASLD. Together with AST, GGT may provide clinicians with concrete, routinely available parameters to monitor for early risk stratification. Further validation in independent cohorts is needed to confirm these findings and inform clinical application.

BACKGROUND:Metabolic dysfunction-associated steatotic liver disease (MASLD) exhibits marked heterogeneity in fibrosis progression and liver-related outcomes. Liver biopsy is not feasible for longitudinal risk stratification at scale, creating a need for validated non-invasive biomarkers, particularly imaging biomarkers, that can predict clinically meaningful disease progression and liver-related outcomes. AIMS:To describe the design and rationale of the GOLDMINE study, established to determine whether non-invasive imaging biomarkers predict MASLD progression and liver-related clinical outcomes. METHODS:GOLDMINE is an investigator-initiated, multi-centre, international longitudinal cohort enrolling up to 1000 adults with either biopsy-proven MASLD or MASLD cirrhosis across the full fibrosis spectrum. Participants are recruited from 15 sites in the US and 4 international sites (Japan, Singapore and France). At baseline, participants undergo clinical phenotyping, vibration-controlled transient elastography, and advanced magnetic resonance imaging (MRI), including proton-density-fat-fraction and magnetic resonance elastography (MRE). MRI (and biospecimen banking) is repeated at 2-year intervals (years 2 and 4), with annual follow-up visits for up to 10 years. Baseline liver histology is centrally processed, digitized and reviewed by a single expert hepatopathologist; all MRI/MREs are centrally interpreted. RESULTS:The prespecified clinical outcomes include progression to cirrhosis, clinically significant portal hypertension, major adverse liver-related outcomes (ascites, hepatic encephalopathy, portal hypertensive bleeding, liver transplantation/qualification), hepatocellular carcinoma, major adverse cardiovascular events, and all-cause mortality, with independent central adjudication of all events. CONCLUSIONS:GOLDMINE establishes a rigorously phenotyped MASLD cohort integrating centralized histology, advanced MRI-based biomarkers, longitudinal biobanking, and adjudicated outcomes, providing a platform to validate imaging and blood-based prognostic biomarkers in MASLD.

We evaluated the prognostic performance of the metabolic vulnerability index (MVX), reflective of inflammation and amino acid dysmetabolism, in a cohort (n = 1613) with the full histological spectrum of MASLD. Over a median follow up of 4 years, MVX predicts all-cause mortality (H.R. 2.7 (95% CI = 2.1-3.5) for every 10-point increment; p < 0.001), liver-related mortality (H.R. 5.1 (95% CI = 2.8-9.1); p < 0.001), hepatic decompensation (H.R. 2.5 (95% CI = 1.8-3.4); p < 0.001), a rise in model for end-stage liver disease (MELD) score to ≥ 15 (H.R. 1.8 (1.4-2.2); p < 0.001) and a decline in eGFR ≥ 40% (H.R. 1.5 (95% CI = 1.2-1.8); p < 0.001). A combination of fibrosis stage and MVX is superior to fibrosis stage alone for prediction of all-cause mortality (AUROC 0.79 vs 0.72, p = 0.01), liver-related mortality (0.95 vs 0.84, p = 0.002) hepatic decompensation (0.88 vs 0.86, p = 0.01) and hepatocellular cancer (0.84 vs 0.78, p = 0.001). These data support further development of MVX as a prognostic biomarker in MASLD.

Background & Aims: Longitudinal outcomes in children with metabolic dysfunction-associated steatotic liver disease (MASLD) remain unclear due to the absence of a standardized monitoring approach. This study aimed to 1) define improvement and worsening in children with MASLD, 2) estimate rates of improvement or deterioration with standard of care (SOC) over one and two years, and 3) identify baseline and longitudinal factors associated with improvement or worsening. Approach and Results: Using data from two large randomized controlled trials, we derived definitions for composite improvement and worsening of MASLD based on associations between changes in ALT, GGT, and liver histology after one and two years. Improvement was defined as ≥40% decrease in ALT and ≥20% decrease in GGT and worsening as ≥20% increase in both ALT and GGT. We applied definitions to a cohort of 440 children with MASLD. After one year of SOC, 22% of children with MASLD showed improvement, increasing to 31% after two years. However, 20% showed worsening after both one and two years despite receiving SOC. Logistic regression analysis, employing stepwise model selection, identified changes in body mass index (BMI) z-score and cholesterol to be most associated with improvement or deterioration. Conclusion: This study developed criteria for improvement and worsening in children with MASLD over one and two years of follow-up. With SOC, over one-quarter of children are likely to improve while one-fifth of children are likely to worsen. Targeting interventions that affect BMI and lipid parameters may help improve MASLD over time.

BACKGROUND:In phase 2 trials involving patients with stage 2 or 3 fibrosis caused by metabolic dysfunction-associated steatohepatitis (MASH), efruxifermin, a bivalent fibroblast growth factor 21 (FGF21) analogue, reduced fibrosis and resolved MASH. Data are needed on the efficacy and safety of efruxifermin in patients with compensated cirrhosis (stage 4 fibrosis) caused by MASH. METHODS:In this phase 2b, randomized, placebo-controlled, double-blind trial, we assigned patients with MASH who had biopsy-confirmed compensated cirrhosis (stage 4 fibrosis) to receive subcutaneous efruxifermin (at a dose of 28 mg or 50 mg once weekly) or placebo. The primary outcome was a reduction of at least one stage of fibrosis without worsening of MASH at week 36. Secondary outcomes included the same criterion at week 96. RESULTS:A total of 181 patients underwent randomization and received at least one dose of efruxifermin or placebo. Of these patients, liver biopsy was performed in 154 patients at 36 weeks and in 134 patients at 96 weeks. At 36 weeks, a reduction in fibrosis without worsening of MASH occurred in 8 of 61 patients (13%) in the placebo group, in 10 of 57 patients (18%) in the 28-mg efruxifermin group (difference from placebo after adjustment for stratification factors, 3 percentage points; 95% confidence interval [CI], -11 to 17; P = 0.62), and in 12 of 63 patients (19%) in the 50-mg efruxifermin group (difference from placebo, 4 percentage points; 95% CI, -10 to 18; P = 0.52). At week 96, a reduction in fibrosis without worsening of MASH occurred in 7 of 61 patients (11%) in the placebo group, in 12 of 57 patients (21%) in the 28-mg efruxifermin group (difference from placebo, 10 percentage points; 95% CI, -4 to 24), and in 18 of 63 patients (29%) in the 50-mg efruxifermin group (difference from placebo, 16 percentage points; 95% CI, 2 to 30). Gastrointestinal adverse events were more common with efruxifermin; most events were mild or moderate. CONCLUSIONS:In patients with compensated cirrhosis caused by MASH, efruxifermin did not significantly reduce fibrosis at 36 weeks. (Funded by Akero Therapeutics; SYMMETRY ClinicalTrials.gov number, NCT05039450.).

Portal inflammation (PI) and ductular reaction (DR) in metabolic dysfunction-associated steatotic liver disease (MASLD) have shown associations with disease severity. We developed a histologic categorization of these features to correlate with known features of MASLD. This study proposes a scoring schema for PI, PP and DR, and relates them to histologic and clinical features in children and adults. This expanded scoring system was developed to identify clinically relevant categories and defined criteria for scoring biopsies. In adults (N:483), more severe PI, PP, and DR were associated with older age (p ≤ 0.002), and PP and DR were associated with increased alkaline phosphatase (ALP) (p ≤ 0.003), GGT (p ≤ 0.001), and total bilirubin (p ≤ 0.01). More severe PI, PP, and DR were associated with higher NAFLD activity score (NAS), fibrosis stage, and diagnosis of metabolic dysfunction-associated steatohepatitis (MASH) (p ≤ 0.05). In children (N:151), PP and DR were associated with younger age (p ≤ 0.0001), and elevated AST, ALT, and ALP (p ≤ 0.05). More severe PI, PP, and DR were associated with advanced fibrosis stage, and PP and DR were associated with diagnosis of borderline or definite MASH in children (p ≤ 0.05). From multivariable ordinal logistic regression analysis, a higher fibrosis stage was independently associated with more severe PI in both adults and children. Interobserver agreement was substantial for PI, PP and DR. The proposed scoring system demonstrated reproducibility and associations between more severe portal-based disease and advanced liver histology, age, and elevated liver enzymes in adults and children. Evaluation of portal disease could provide insight into therapeutic response and disease progression.

BACKGROUND & AIMS:The association between genetic variants and longitudinal changes in liver histology has not been well characterized. We examined relationships between three single nucleotide polymorphisms (SNPs) - PNPLA3 rs738409, TM6SF2 rs58542926, and HSD17B13 rs72613567 - and longitudinal changes in liver histology. METHODS:A total of 671 (444 adults and 227 children) individuals enrolled in different NASH CRN studies and randomized controlled trials, with ≥2 serial liver biopsies, were analyzed. The main outcomes were progression from metabolic dysfunction-associated steatotic liver (MASL) to steatohepatitis (MASH), ≥1 stage increase in fibrosis, and resolution of MASH or fibrosis regression ≥1 stage. Interval-censored Cox models, adjusted for race/ethnicity, sex, age, BMI, type 2 diabetes mellitus (T2DM), and study cluster, were used to examine the associations between genetic variants and histological outcomes. RESULTS:The PNPLA3 G allele increased the risk of fibrosis progression (adjusted hazard ratio [aHR] 1.31, 95% CI 1.05-1.64). The HSD17B13 A allele attenuated MASL to MASH progression (aHR 0.46, 95% CI 1.5-3.9) and fibrosis progression (aHR 0.69, 95% CI 0.51-0.92) while increasing the likelihood of MASH resolution (aHR 1.58, 95% CI 1.13-2.22) and fibrosis regression (aHR 1.42, 95% CI 1.09-1.85). The TM6SF2 T allele did not influence histological changes. An unweighted 3-SNP polygenic risk score, incorporating PNPLA3, HSD17B13, and TM6SF2 risk alleles, was associated with an increased risk of MASL to MASH progression (aHR 1.33, 95% CI 1.03-1.71) and fibrosis progression (aHR 1.37, 95% CI 1.18-1.60). The unweighted sum of the 3-SNP non-risk alleles was associated with a higher chance of MASH resolution (aHR 1.21, 95% CI 1.02-1.43). Non-genetic factors, including T2DM and BMI change, also independently influenced histology. The effects of single variants and the PRS were significantly modified by age, sex, BMI, and T2DM. CONCLUSION:Genetic predisposition and its significant interactions with non-genetic factors drive the dynamic trajectory of MASLD, providing a critical framework for personalized risk stratification and management. IMPACT AND IMPLICATIONS:Histological changes in metabolic dysfunction-associated steatotic liver disease are driven by complex interactions between genetic and non-genetic factors, not by isolated influences. The PNPLA3 rs738409 allele worsened fibrosis and steatosis, while the HSD17B13 rs72613567 allele acted as a protective factor against progression and promoted regression. A polygenic risk score (PRS), based on three single nucleotide polymorphisms, comprising the sum of the three risk alleles, independently predicted histological progression. Conversely, the PRS of the three non-risk alleles was associated with histological regression. Non-genetic factors such as age, sex, BMI changes, and type 2 diabetes mellitus significantly modified the impact of both single genetic variants and the PRS on histology. These findings underscore the necessity of considering these multifaceted interactions for personalized MASLD management, including risk stratification and future therapeutic development.

Background & Aims: Metabolic dysfunction-associated steatotic liver disease (MASLD) is the most common chronic liver disease in children, but its long-term outcomes are poorly understood. This study aimed to quantify mortality rates, identify causes of death, and evaluate the incidence of cirrhosis and extrahepatic outcomes in children with pediatric-onset MASLD. Approach & Results: The Longitudinal InVestigation Evaluating Results of Steatosis (LIVERS) study is a single-center, retrospective cohort study conducted at Rady Children's Hospital San Diego. We included 1,096 children aged 2-18 years who were diagnosed with MASLD between 2000 and 2017 and followed for a mean of 8.5 years. Mortality was ascertained via the National Death Index, and comorbidities were assessed through follow-up research visits and medical records. Overall, 3.4% of children died, yielding a mortality rate of 398 per 100,000 person-years; nearly half of these deaths were liver-related. Male sex and lower high-density lipoprotein levels independently predicted increased mortality risk. The cumulative incidence of cirrhosis was 4.7%. High incidence rates of extrahepatic comorbidities were observed, including dyslipidemia (3,664 per 100,000 person-years), hypertension (1,901), obstructive sleep apnea (1,185), and type 2 diabetes (911). Conclusions: Pediatric MASLD is associated with significant premature mortality and a substantial burden of hepatic and extrahepatic comorbidities. These findings highlight the need for timely screening, early intervention, and long-term management strategies to improve outcomes for children with MASLD.

OBJECTIVES:Metabolic dysfunction-associated steatotic liver disease (MASLD) is a prevalent disease in children. Vibration-controlled transient elastography (VCTE) offers a noninvasive alternative to liver biopsy, using controlled attenuation parameter (CAP) to estimate steatosis and liver stiffness measurement (LSM) for fibrosis. However, pediatric data with histological validation are limited. This prospective, multicenter study evaluated the accuracy of CAP and LSM in pediatric MASLD. METHODS:Children with histologically confirmed MASLD from the Nonalcoholic Steatohepatitis Clinical Research Network (NASH CRN) Database 3 underwent VCTE within 6 months of liver biopsy. CAP was evaluated for correlation with steatosis grades, and LSM for correlation with fibrosis stages. The diagnostic performance of LSM in distinguishing fibrosis stages was analyzed using histological findings as the reference standard. RESULTS:Among 92 children with MASLD (mean age 13 ± 3 years), CAP values were similar across steatosis grades (median 325, 310, and 323 dB/m for grades 1-3, respectively) and showed no significant correlation with histologic steatosis (p = 0.422). Median LSM values increased with fibrosis stage (6.0-8.8 kPa), but significant differences were detected only between stage 0 and stage 3 fibrosis (p = 0.037). For advanced fibrosis (stages 3-4), area under the receiver operating characteristic curve was 0.67, with sensitivity 67%, specificity 76%, positive predictive value 40%, and negative predictive value 90%. CONCLUSION:In this prospective, multicenter cohort, VCTE showed modest accuracy for grading steatosis or staging fibrosis in pediatric MASLD. Improved noninvasive methods are urgently needed for evaluation and monitoring in this population.

BACKGROUND & AIMS:Assessment of histologic disease activity (grading) and fibrosis (staging) is a prerequisite for patient selection and evaluation of treatment response in clinical trials of metabolic dysfunction-associated steatohepatitis (MASH). The lack of universally accepted definitions of histological components required for metabolic dysfunction-associated steatotic liver disease (MASLD) grading and staging, inconsistent histologic interpretations, and the absence of guidelines on how to apply currently used scoring systems, contribute to high interobserver variation and influence supervised machine learning algorithms. METHODS:The International MASLD Pathology Group (IMPG), comprising 25 expert liver pathologists and one statistician, was established to develop guidance for the histological assessment of liver biopsies in MASH clinical trials and to define standards for liver biopsy processing, as well as to refine criteria for histological MASLD grading and staging. Statements were generated by three IMPG working subgroups and evaluated through a Delphi consensus procedure. RESULTS:The IMPG working groups issued a total of 278 primary statements, which were evaluated in the first Delphi round, yielding 162 statements with 80% or higher agreement. The remaining 116 statements were discussed and either revised or not further considered. The resulting 33 revised statements were evaluated in a second Delphi round, yielding 192 final statements with 80% or higher agreement. CONCLUSION:For the first time, the IMPG statements provide guidelines to promote consensus among liver pathologists on the histopathological evaluation and scoring of liver biopsies for MASH clinical trials. Furthermore, they may inform the development of supervised machine learning algorithms for quantitative histology assessments of MASLD. IMPACT AND IMPLICATIONS:Inter- (and intra-) observer variations in the histological interpretation of key morphological features of metabolic dysfunction-associated steatohepatitis (MASH) limit the precision of histological grading and staging, as well as the diagnosis of the histological subtypes, MASL and MASH. This is thought to account, at least in part, for screening failure and variable placebo response rates in clinical trials, potentially obscuring treatment effects. The International MASLD Pathology Group, consisting of 25 expert liver pathologists, generated consensus statements for histopathological procedures, technical aspects and histological criteria for the diagnosis of MASH, as well as for grading disease activity and staging fibrosis. These may provide a basis for standardized histologic interpretation and the development of AI-based grading and staging algorithms for clinical trials of MASH.