Ibrahim, Samar H.

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.

Abstract Context Variants in melanocortin 4 receptor (MC4R) pathway-related genes have been associated with obesity. The association of these variants with cardiometabolic parameters are not fully known. Objective We compared the severity of obesity and cardiometabolic risk markers in children with MC4R pathway-related clinically reported genetic variants relative to children without these variants. Methods A retrospective chart review was performed in children with obesity who underwent multigene panel testing for monogenic obesity. Results Data on a total of 104 children were examined, with 93 (89%) identified as White. Thirty-nine (37.5%) patients had clinically reported variants in the MC4R pathway, and the remaining 65 patients did not have reported MC4R pathway-related variants. Among the MC4R-related variants, PCSK1 risk alleles were most common, reported in 15 children (14%). The maximum body mass index percent of the 95th percentile was not different between groups (P = .116). Low-density lipoprotein cholesterol (LDL-C) was not different between groups (P = .132). However, subgroup analysis demonstrated higher LDL cholesterol in children with the PCSK1 c.661A>G risk allele relative to those with MC4R-related variant of uncertain significance (P = .047), negative genetic testing (P = .012), and those with non-MC4R related variants (P = .048). The blood pressure, fasting glucose, hemoglobin A1C, total cholesterol, alanine transaminase, and high-density lipoprotein cholesterol were not different between groups. Conclusion Variants in the MC4R pathway-related genes were not associated with severity of obesity and cardiometabolic risk markers except for the c.661A>G PCSK1 risk allele, which was associated with higher LDL-C levels.

AbstractObjectivesTo compare long‐term transplant outcomes (organ rejection and retransplant) of simultaneous liver/kidney transplant (SLK) versus isolated kidney transplant (IK) for patients with primary hyperoxaluria (PH).MethodsThe Rare Kidney Stone Consortium PH registry was queried to identify patients with PH who underwent SLK or IK from 1999 to 2021. Patient characteristics and long‐term transplant outcomes were abstracted and analyzed. Statistical comparisons were performed with Kaplan–Meier plots and Cox proportional hazards models.ResultsWe identified 250 patients with PH, of whom 35 received care at Mayo Clinic and underwent SLK or IK. Patients who underwent SLK as their index transplant had lower odds of kidney rejection than did those who underwent IK (hazard ratio [HR], 0.29; 95% confidence interval [CI], 0.08–0.99; p = .048). The immunoprotective effect of concomitant liver and kidney transplant appeared to enhance outcomes for patients with PH. Additionally, the odds of retransplant were significantly lower for patients who underwent SLK as their index transplant than for those who underwent IK (HR, 0.08; 95% CI, 0.02–0.42; p = .003). Of five patients who underwent IK and had maintained graft function for at least 5 years after transplant, three (60%) had documented vitamin B6 responsiveness.ConclusionsPatients with PH who underwent SLK had a lower risk of kidney rejection and retransplant than those who underwent IK. Accurate genetic assessment for vitamin B6 responsiveness may optimize IK allocation. Novel therapeutics, such as lumasiran, have been introduced as promising agents for the management of PH.

AbstractMetabolic dysfunction‐associated steatotic liver disease (MASLD) is increasing globally in pediatric populations. Currently, MASLD management primarily relies on lifestyle interventions, which pose challenges in sustaining long‐term weight loss. This study investigated the use of weight loss medications in MASLD care through an international survey of 166 pediatric gastroenterologists and hepatologists. The results indicated a notable interest in weight loss medications, with 38% of practitioners considering or using them, particularly glucagon‐like peptide‐1 receptor agonists. However, the survey also revealed a tendency among clinicians to refer patients to specialists, emphasizing the potential gap between acknowledgment and prescription practices. Challenges include the lack of guidelines and uncertainty regarding side effects. The study highlights a pressing need for education, with over 90% of the respondents expressing an interest. Our study highlights the current management of MASLD, the potential role of pharmacotherapy, and highlights avenues for improved care and education in this dynamic field.

Steatohepatitis with diverse etiologies is the most common histological manifestation in patients with liver disease. However, there are currently no specific histopathological features pathognomonic for metabolic dysfunction–associated steatotic liver disease, alcohol-associated liver disease, or metabolic dysfunction–associated steatotic liver disease with increased alcohol intake. Digitizing traditional pathology slides has created an emerging field of digital pathology, allowing for easier access, storage, sharing, and analysis of whole-slide images. Artificial intelligence (AI) algorithms have been developed for whole-slide images to enhance the accuracy and speed of the histological interpretation of steatohepatitis and are currently employed in biomarker development. Spatial biology is a novel field that enables investigators to map gene and protein expression within a specific region of interest on liver histological sections, examine disease heterogeneity within tissues, and understand the relationship between molecular changes and distinct tissue morphology. Here, we review the utility of digital pathology (using linear and nonlinear microscopy) augmented with AI analysis to improve the accuracy of histological interpretation. We will also discuss the spatial omics landscape with special emphasis on the strengths and limitations of established spatial transcriptomics and proteomics technologies and their application in steatohepatitis. We then highlight the power of multimodal integration of digital pathology augmented by machine learning (ML)algorithms with spatial biology. The review concludes with a discussion of the current gaps in knowledge, the limitations and premises of these tools and technologies, and the areas of future research.

Nonalcoholic steatohepatis (NASH) is characterized by excess circulating toxic lipids, along with hepatic steatosis, and recruited myeloid cells-mediated liver inflammation. Myeloid cells adhesion to the liver sinusoidal endothelial cells (LSEC) and transendothelial migration are crucial elements in the inflammatory process, and LSEC under lipotoxic stress develop a pro-inflammatory phenotype known as endotheliopathy. However, the exact mechanisms of this phenomenon are obscure. To define the molecular mediators of LSEC endotheliopathy, we isolated primary mouse LSECs from C57BL/6J mice on chow or a NASH-inducing diet rich in fat, fructose, and cholesterol (FFC), and subjected them to multi-omics studies. An integrated pathway analysis of the mouse LSEC proteomics and transcriptomics indicates that leukocyte transendothelial migration and focal adhesion are the major pathways altered in NASH LSEC. To explore the LSEC intracellular signaling networks, we performed kinome profiling of the LSEC phospho-proteomics and identified Glycogen Synthase Kinase 3 (GSK3)β as the major hub, and the top kinase in NASH. We then confirmed that GSK3β is activated in primary human LSEC treated with the toxic lipid Palmitate (PA). PA also promoted the LSEC pro-inflammatory response by upregulating CXCL2 and intracellular adhesion molecule 1 (ICAM-1) , all of which were attenuated with the GSK3 inhibitor LY2090314 (LY). Using a collagen gel-based transmigration assay, we demonstrated that THP-1 monocyte migration through an LSEC monolayer treated with PA was reduced by LY. In FFC-fed mice, LY treatment ameliorated liver inflammation, injury, and fibrosis as assessed by reduced F4/80, MPO, and ICAM-1 immuno-staining, ALT serum levels and hepatic TUNEL-positive cells, Sirius red and alpha smooth muscle actin staining of the liver. Mice with NASH-induced diet had reduced haptic neutrophil and proinflammatory monocyte infiltration when treated with ICAM1 neutralizing antibody. Furthermore, we confirmed increased LSEC expression of ICAM1 in human with NASH. In conclusion, GSK3 inhibition attenuates toxic lipid induced LSEC pro-inflammatory phenotype and may serve as a potential therapeutic strategy in human NASH.

Background: NASH is the progressive form of NAFLD characterized by lipotoxicity, hepatocyte injury, tissue inflammation, and fibrosis. Previously, Rho-associated protein kinase (ROCK) 1 has been implicated in lipotoxic signaling in hepatocytes in vitro and high-fat diet-induced lipogenesis in vivo. However, whether ROCK1 plays a role in liver inflammation and fibrosis during NASH is unclear. Here, we hypothesized that pathogenic activation of ROCK1 promotes murine NASH pathogenesis. Methods and Results: Patients with NASH had increased hepatic ROCK1 expression compared with patients with fatty liver. Similarly, hepatic ROCK1 levels and activity were increased in mice with NASH induced by a western-like diet that is high in fat, fructose, and cholesterol (FFC). Hepatocyte-specific ROCK1 knockout mice on the FFC diet displayed a decrease in liver steatosis, hepatic cell death, liver inflammation, and fibrosis compared with littermate FFC-fed controls. Mechanistically, these effects were associated with a significant attenuation of myeloid cell recruitment. Interestingly, myeloid cell-specific ROCK1 deletion did not affect NASH development in FFC-fed mice. To explore the therapeutic opportunities, mice with established NASH received ROCKi, a novel small molecule kinase inhibitor of ROCK1/2, which preferentially accumulates in liver tissue. ROCK inhibitor treatment ameliorated insulin resistance and decreased liver injury, inflammation, and fibrosis. Conclusions: Genetic or pharmacologic inhibition of ROCK1 activity attenuates murine NASH, suggesting that ROCK1 may be a therapeutic target for treating human NASH.

LSECs are a unique population of endothelial cells within the liver and are recognized as key regulators of liver homeostasis. LSECs also play a key role in liver disease, as dysregulation of their quiescent phenotype promotes pathological processes within the liver including inflammation, microvascular thrombosis, fibrosis, and portal hypertension. Recent technical advances in single-cell analysis have characterized distinct subpopulations of the LSECs themselves with a high resolution and defined their gene expression profile and phenotype, broadening our understanding of their mechanistic role in liver biology. This article will review 4 broad advances in our understanding of LSEC biology in general: (1) LSEC heterogeneity, (2) LSEC aging and senescence, (3) LSEC role in liver regeneration, and (4) LSEC role in liver inflammation and will then review the role of LSECs in various liver pathologies including fibrosis, DILI, alcohol-associated liver disease, NASH, viral hepatitis, liver transplant rejection, and ischemia reperfusion injury. The review will conclude with a discussion of gaps in knowledge and areas for future research.