Ibrahim, Samar H

Noncirrhotic portal hypertension has historically been described using heterogeneous and region-specific terminology—such as idiopathic portal hypertension (IPH), noncirrhotic portal fibrosis (NCPF), obliterative portal venopathy, and nodular regenerative hyperplasia—leading to substantial variability in diagnosis, reporting, and international research collaboration. Differences in guideline definitions from major societies (AASLD, EASL, and APASL), together with the presence of characteristic histologic lesions in patients without clinically overt portal hypertension, have further complicated disease classification. To address these challenges, a large, multisociety, international initiative was convened to harmonize nomenclature and diagnostic criteria. Representatives from liver, pathology, and pediatric hepatology societies across the Americas, Europe, and Asia participated in a structured consensus process that included specialized working groups and external Delphi validation. The initiative produced a globally harmonized and implementable diagnostic framework. Consensus was reached that the terms porto-sinusoidal vascular disorder (PSVD) and NCPF may be used interchangeably when identical diagnostic criteria are applied, and that they should be written as PSVD or NCPF . The diagnosis was defined as fundamentally clinicopathological, requiring integrated assessment. Core principles include the need for a high-quality liver biopsy (≥10 mm), mandatory exclusion of cirrhosis, and systematic exclusion of specific alternative conditions. Importantly, the consensus recognizes that PSVD or NCPF may be diagnosed even without clinical portal hypertension and may coexist with other liver diseases, provided cirrhosis is excluded. Standardized major and minor histologic criteria were developed collaboratively by expert pathologists and externally validated. Features of portal hypertension were harmonized into specific and nonspecific categories applicable to routine clinical practice. An integrated diagnostic scoring system incorporating histology, clinical features, associated conditions, and concommitant etiologies was developed and validated using the Delphi method. This consensus provides the first internationally endorsed, unified framework for the diagnosis of PSVD or NCPF. Its global implementation is expected to reduce diagnostic variability, improve comparability across regions, and facilitate the development of robust, internationally harmonized clinical and translational research cohorts.

In metabolic dysfunction–associated steatohepatitis (MASH), liver sinusoidal endothelial cells (LSECs) acquire a proinflammatory phenotype termed lipotoxic endotheliopathy. We previously identified glycogen synthase kinase 3β (GSK3β) as a central signaling hub in LSECs during MASH. To elucidate the molecular mechanisms and functional outcome of lipotoxicity-induced GSK3β activation in LSECs, we utilized endothelial cell–specific Gsk3 β -KO ( Gsk3 β ΔEnd ) mice fed MASH-inducing diets. Endothelial Gsk3 β deletion significantly reduced markers of lipotoxic endotheliopathy, including adhesion molecules and chemokines, alongside liver injury, inflammation, and fibrosis. Immune profiling via flow cytometry and mass cytometry by time of flight (CyTOF) identified decreased hepatic infiltration of proinflammatory myeloid populations, particularly mature DCs in Gsk3 β ΔEnd mice. In a coculture system, GSK3β in lipotoxic LSECs promoted DCs maturation. Mechanistically, GSK3 inhibition restored lipotoxicity-induced alterations in LSEC mitochondrial morphology and respiration by regulating AMP-activated protein kinase and dynamin-related protein 1. This rescue suppressed chemokine and adhesion molecule expression, thereby limiting immune cell recruitment. Collectively, under lipotoxic stress, GSK3β amplifies mitochondrial dysfunction and inflammatory signaling in LSECs, enhancing myeloid cell homing and DC maturation. Targeting LSEC GSK3β may, therefore, represent a promising therapeutic strategy to mitigate LSEC-driven fibroinflammatory response in human MASH.

Background and Aims: Liver sinusoidal endothelial cells (LSECs) acquire a proinflammatory phenotype in metabolic dysfunction–associated steatohepatitis (MASH), characterized by enhanced expression of adhesion molecules and inflammatory mediators, a process termed lipotoxic endotheliopathy. However, the molecular drivers of this transformation remain incompletely defined. Approach and Results: We employed complementary models of lipotoxicity and MASH, including palmitate-treated primary human LSECs (in vitro), cultured precision-cut liver slices (PCLS) from MASH mice and normal human liver treated with MASH-inducing media (ex vivo), and diet-induced MASH models (in vivo). GeoMx digital spatial profiling of human MASH livers revealed enriched proinflammatory and fibrogenic signaling between LSECs and myeloid cells. Among the top upregulated genes and ligand–receptor pairs was ICAM1 , whose expression correlated with disease severity and was increased in human MASH by immunostaining. ATAC-seq on primary mouse LSECs showed enhanced chromatin accessibility at the Icam1 promoter in MASH. Chromatin immunoprecipitation confirmed enrichment of the active epigenetic mark H3K27ac and BRD4 binding at the ICAM1 promoter in human LSECs under lipotoxic stress. Mechanistically, we identified the GSK3β/c-Jun/BRD4 axis as a key regulator of ICAM1 induction in LSECs. In vivo, ICAM1-neutralizing antibody or endothelial-specific epigenetic suppression reduced hepatic inflammation, injury, and fibrosis in MASH mice. Conclusions: ICAM1 is epigenetically upregulated in LSECs during lipotoxic stress and promotes myeloid cell recruitment in MASH. Targeting the epigenetic regulation of ICAM1 may offer a novel therapeutic strategy for treating human MASH.

Receptor activator of nuclear factor kappa B ligand (RANKL) is an essential cytokine that induces osteoclastic differentiation by monocyte-macrophage lineage precursors. Here, we showed that in addition to its conventional action, RANKL controls vascular permeability in the bone marrow, where it facilitates the mobilization of hematopoietic monocytic cells, including osteoclast precursors, and resultantly regulates bone metabolism. RANK, a cognate receptor for RANKL, is abundantly expressed in sinusoidal endothelial cells and controls vascular permeability by regulating the expression patterns of intercellular adhesion molecule 1 and vascular cell adhesion molecule 1. High RANKL expression was detected in perivascular C–X–C motif chemokine ligand 12-abundant reticular (CAR) stromal cells. Specific deletion of RANKL expression in CAR cells abrogated the vascular leakage, suggesting that perivascular RANKL is responsible for controlling permeability. In summary, our study revealed a role for RANK/RANKL signaling as a gatekeeper of bone marrow sinusoids in vivo.

Metabolic dysfunction–associated steatotic liver disease (MASLD) is the most common pediatric liver disease, affecting approximately 10% of children. Its prevalence is rising at an alarming rate, with cases increasingly identified even in early childhood. While MASLD shares key features across the lifespan, its earlier onset reflects developmental vulnerabilities and unique mechanistic drivers. Perinatal influences, including maternal obesity, gestational diabetes, and early-life nutritional exposures, play a central role by disrupting metabolic programming, driving mitochondrial dysfunction, and inducing epigenetic modifications. These early stressors interact with genetic predispositions, such as PNPLA3 and TM6SF2 variants, to amplify susceptibility and shape disease severity. Pediatric MASLD also exhibits distinct histological features, particularly predominant periportal (zone 1) steatosis, inflammation, and fibrosis, which contrast with the centrilobular or pericentral (zone 3) patterns often seen in adults. These findings provide insight into spatial heterogeneity, developmental pathophysiology, and unique disease progression trajectories in children. Addressing MASLD in children requires pediatric-specific approaches to diagnosis, risk stratification, and intervention. By integrating epidemiological trends, mechanistic insights, and translational advances, this Review highlights opportunities for targeted therapies and prevention strategies aimed at mitigating early-life drivers of MASLD, reducing disease burden, and improving long-term outcomes.

Pediatric metabolic dysfunction–associated steatotic liver disease (MASLD) has become more prevalent on a global scale over the last decades and is associated with significant comorbidities in childhood and a 40-fold higher risk of early mortality in young adulthood. MASLD has now become the leading indication for liver transplantation in young adults in the United States. However, pediatric MASLD is still perceived as an indolent condition by many patients, families, and clinicians. In this Call to Action, we aim to raise awareness of pediatric MASLD as a public health crisis. Herein, we describe insufficient screening and disease staging practices, and a lack of accurate non-invasive tests and effective pharmacotherapy, both stemming from a paucity of multicenter clinical trials in pediatric MASLD. We provide clear steps to address this public health emergency by promoting awareness campaigns, educating and empowering patients and families, addressing barriers including access to care, nutritional and exercise support programs, establishing multidisciplinary care, launching community initiatives, and conducting clinical trials in pediatric MASLD for an age-based evaluation of novel diagnostic and therapeutic options. We conclude by highlighting the urgent need for comprehensive public health policies to control the tide of pediatric MASLD and call upon stakeholders to act now.

ABSTRACT Background The Society of Pediatric Liver Transplantation (SPLIT) has undergone tremendous growth with > 45 sites contributing data focusing on improving outcomes in pediatric liver transplantation (LT). We report and compare outcomes from the SPLIT Registry. Methods Patients < 18 years with first‐time LT only enrolled into the SPLIT Registry between 2011 and 2023 were included. Data was stratified into eras from the last published registry update (era 1: 2011–2018, era 2: 2018–2023). Results Three thousand five hundred four participants from 47 centers were included (era 1: n = 2159; era 2: n = 1345). Age distribution differed with more children < 1 year. of age at LT in era 2 (era 1: 29% vs. era 2: 33%, p = 0.01). Indications for LT were similar, with biliary atresia (38.8%) and metabolic disease (16.0%) being most common. Exception point use was higher in era 2 (era 1: 45% vs. era 2: 56%, p < 0.001). No difference in graft type (deceased: 81% era 1 vs. 78% era 2, p = 0.78), patient survival at 90 days (era 1: 98.7% vs. era 2: 98.3%), 1 year (era 1: 97.2 vs. era 2: 96.8%), or 3 years (era 1: 95.3% vs. era 2: 95.2%) was noted. Rate of hepatic artery thrombosis was lower in era 2 (era 1: 7% vs. era 2: 5%, p = 0.02). Conclusions Trends in pediatric LT within SPLIT note similar LT indications and graft type, higher utilization of exception points, and lower HAT rates despite transplanting more children < 10 kg. This data underscores the evolution of pediatric LT toward higher survivability and overall patient outcomes.

AbstractAs rates of obesity rise worldwide, incidence of metabolic dysfunction‐associated steatotic liver disease (MASLD), formerly referred to as nonalcoholic fatty liver disease, is increasing, worsening the burden of healthcare systems. The council of the Federation of International Societies for Pediatric Gastroenterology, Hepatology, and Nutrition (FISPGHAN) identified the topic of MASLD epidemiology, treatment, and prevention as a global priority issue to be addressed by an expert team, with the goal to describe feasible and evidence‐based actions that may contribute to reducing MASLD risk. The FISPGHAN member societies nominated experts in the field. The FISPGHAN council selected and appointed members of the expert team and a chair. The subtopics included in this manuscript were chosen through a consensus of the experts involved. We review the epidemiology, natural history, and screening and management. We further expand to relevant public health measures aimed at MASLD prevention, including identifying interventions that could reduce risk factors (environmental and iatrogenic), optimize maternal and newborn health, and support healthier lifestyles for older children and adolescents on a local, national, and international scale. While recognizing that various aspects of population health and public policy can shape MASLD risk, we also review what we can do on an individual level to support our patients to reduce the significant burden of this ever rising disease in pediatrics.

AbstractPediatric obesity, characterized by a body mass index (BMI) at or above the 95th percentile for age, affects a substantial number of children and adolescents worldwide. Metabolic dysfunction‐associated steatotic liver disease (MASLD), formerly known as nonalcoholic fatty liver disease, represents a prominent hepatic manifestation of obesity and metabolic syndrome, emerging as the most prevalent hepatic disorder among pediatric patients and a significant contributor to liver transplantation in adults. The escalating prevalence of pediatric MASLD mirrors the alarming rise in childhood obesity rates over recent decades. While lifestyle modifications focusing on dietary changes and increased physical activity constitute the cornerstone of MASLD management, achieving and maintaining significant weight reduction remains challenging. Moreover, disease progression often persists despite standard‐of‐care interventions, warranting exploration into alternative therapeutic strategies. Pharmacological interventions, particularly, glucagon‐like peptide‐1 receptor agonists (GLP‐1RA), have shown promise in addressing pediatric obesity and its associated comorbidities, including MASLD. Recent studies have demonstrated the efficacy of GLP‐1RA in inducing weight loss and improving liver enzyme levels, suggesting a potential role in halting disease progression, and reducing the risk of major adverse liver outcomes. This review provides a comprehensive overview of the current pharmacotherapy landscape for pediatric MASLD, with a focus on novel agents such as GLP‐1RA. Furthermore, the manuscript proposes a practical algorithm to assist in integrating GLP‐1RA into the clinical management of pediatric patients with obesity and MASLD. Despite promising results, further research is warranted to elucidate the long‐term efficacy and safety of GLP‐1RA in pediatric populations.