Metabolism-Disrupting Chemical Mixtures during Pregnancy, Folic Acid Supplementation, and Liver Injury in Mother-Child Pairs.

Background and Aims: Scarce knowledge about the impact of metabolism-disrupting chemicals (MDCs) on liver injury limits opportunities for intervention. We evaluated pregnancy MDC-mixture associations with liver injury and effect modification by folic acid (FA) supplementation in mother-child pairs. Methods: We studied ∼200 mother-child pairs from the Mexican PROGRESS cohort, with measured 43 MDCs during pregnancy (estimated air pollutants, blood/urine metals or metalloids, urine high- and low-molecular-weight phthalate [HMWPs, LMWPs] and organophosphate-pesticide [OP] metabolites), and serum liver enzymes (ALT, AST) at ∼9 years post-parturition. We defined liver injury as elevated liver enzymes in children, and using established clinical scores for steatosis and fibrosis in mothers (i.e., AST:ALT, FLI, HSI, FIB-4). Bayesian Weighted Quantile Sum regression assessed MDC-mixture associations with liver injury outcomes. We further examined chemical-chemical interactions and effect modification by self-reported FA supplementation. Results: In children, many MDC-mixtures were associated with liver injury outcomes. Per quartile HMWP-mixture increase, ALT increased by 10.1% (95%CI: 1.67%, 19.4%) and AST by 5.27% (95% CI: 0.80%, 10.1%). LMWP-mixtures and air pollutant-mixtures were associated with higher AST and ALT, respectively. Air pollutant and non-essential metal/element associations with liver enzymes were attenuated by maternal cobalt blood concentrations ( p -interactions<0.05). In mothers, only the LMWP-mixture was associated with liver injury [OR=1.53 (95%CI: 1.01, 2.28) for HSI>36, and OR=1.62 (95%CI: 1.05, 2.49) for AST:ALT<1]. In mothers and children, most associations were attenuated (null) at FA supplementation≥600mcg/day ( p -interactions<0.05). Conclusions: Pregnancy MDC exposures may increase liver injury risk, particularly in children. These associations may be attenuated by higher FA supplementation and maternal cobalt levels.

Fibrosis and steatotic liver disease in US adolescents according to the new nomenclature.

OBJECTIVE: To apply the new nomenclature for steatotic liver diseases (SLD), replacing nonalcoholic fatty liver disease (NAFLD) with metabolic dysfunction-associated steatotic liver disease (MASLD), in adolescents using National Health and Nutrition Examination Survey (NHANES) data. METHODS: Among 1410 adolescents (12-19 years) in NHANES (2017-March, 2020), the controlled attenuation parameter (CAP) of transient elastography (TE) was used to define steatosis and fibrosis (TE ≥ 7.4 kPa). Obesity and alanine aminotransferase (ALT) ≥ 80 U/L were used to identify adolescents qualifying for hepatology referral according to practice guidelines. NAFLD was defined as liver steatosis without a specific exposure; it has no cardiometabolic risk factor requirement, unlike MASLD. RESULTS: Steatosis (yes/no) is the first decision point in the new diagnostic protocol; however, criteria for steatosis are undefined. At the supplier (EchoSens)-recommended CAP threshold of 240 dB/m, 30.5% (95% confidence interval [CI]: 27.1%-34.0%) of adolescents had SLD and about 85% of adolescents with NAFLD met criteria for MASLD. The other 15% would receive an ambiguous diagnosis of either cryptogenic SLD or possible MASLD. At higher CAP thresholds, MASLD/NAFLD concordance increased and approached 100%. Among adolescents with MASLD-fibrosis, only 8.8% (95% CI: 0%-19.3%) had overweight/obese and ALT ≥ 80 U/L. CONCLUSIONS: The new nomenclature highlights the high prevalence of liver steatosis. At the CAP threshold of 240 dB/m, however, approximately 15% of adolescents would receive an ambiguous diagnosis, which could lead to confusion and worry. Fewer than 10% of adolescents with MASLD-fibrosis had overweight/obese and ALT ≥ 80 U/L. Revised guidelines are needed to ensure that the other 90% receive appropriate referral and liver disease care.

Shwachman-Diamond syndrome mimicking mitochondrial hepatopathy.

Shwachman-Diamond syndrome (SDS) is a genetic disorder caused by mutations in the Shwachman-Bodian-Diamond syndrome (SBDS) gene. The syndrome is characterized by multiorgan dysfunction primarily involving the bone marrow and exocrine pancreas. Frequently overlooked is the hepatic dysfunction seen in early childhood which tends to improve by adulthood. Here, we report a child who initially presented with failure to thrive and elevated transaminases, and was ultimately diagnosed with SDS. A liver biopsy electron micrograph revealed hepatocytes crowded with numerous small mitochondria, resembling the hepatic architecture from patients with inborn errors of metabolism, including mitochondrial diseases. To our knowledge, this is the first report of the mitochondrial phenotype in an SDS patient. These findings are compelling given the recent cellular and molecular research studies which have identified SBDS as an essential regulator of mitochondrial function and have also implicated SBDS in the maintenance of mitochondrial DNA.

Mannose Supplementation Curbs Liver Steatosis and Fibrosis in Murine MASH by Inhibiting Fructose Metabolism.

Metabolic dysfunction-associated steatohepatitis (MASH) can progress to cirrhosis and liver cancer. There are no approved medical therapies to prevent or reverse disease progression. Fructose and its metabolism in the liver play integral roles in MASH pathogenesis and progression. Here we focus on mannose, a simple sugar, which dampens hepatic stellate cell activation and mitigates alcoholic liver disease in vitro and in vivo . In the well-validated FAT-MASH murine model, oral mannose supplementation improved both liver steatosis and fibrosis at low and high doses, whether administered either at the onset of the model ("Prevention") or at week 6 of the 12-week MASH regimen ("Reversal"). The in vivo anti-fibrotic effects of mannose supplementation were validated in a second model of carbon tetrachloride-induced liver fibrosis. In vitro human and mouse primary hepatocytes revealed that the anti-steatotic effects of mannose are dependent on the presence of fructose, which attenuates expression of ketohexokinase (KHK), the main enzyme in fructolysis. KHK is decreased with mannose supplementation in vivo and in vitro, and overexpression of KHK abrogated the anti-steatotic effects of mannose. Our study identifies mannose as a simple, novel therapeutic candidate for MASH that mitigates metabolic dysregulation and exerts anti-fibrotic effects.

PFAS Exposures and the Human Metabolome: A Systematic Review of Epidemiological Studies.

Purpose of Review: There is a growing interest in understanding the health effects of exposure to per- and polyfluoroalkyl substances (PFAS) through the study of the human metabolome. In this systematic review, we aimed to identify consistent findings between PFAS and metabolomic signatures. We conducted a search matching specific keywords that was independently reviewed by two authors on two databases (EMBASE and PubMed) from their inception through July 19, 2022 following PRISMA guidelines. Recent Findings: We identified a total of 28 eligible observational studies that evaluated the associations between 31 different PFAS exposures and metabolomics in humans. The most common exposure evaluated was legacy long-chain PFAS. Population sample sizes ranged from 40 to 1,105 participants at different stages across the lifespan. A total of 19 studies used a non-targeted metabolomics approach, 7 used targeted approaches, and 2 included both. The majority of studies were cross-sectional (n = 25), including four with prospective analyses of PFAS measured prior to metabolomics. Summary: Most frequently reported associations across studies were observed between PFAS and amino acids, fatty acids, glycerophospholipids, glycerolipids, phosphosphingolipids, bile acids, ceramides, purines, and acylcarnitines. Corresponding metabolic pathways were also altered, including lipid, amino acid, carbohydrate, nucleotide, energy metabolism, glycan biosynthesis and metabolism, and metabolism of cofactors and vitamins. We found consistent evidence across studies indicating PFAS-induced alterations in lipid and amino acid metabolites, which may be involved in energy and cell membrane disruption.

Evaluation of 2-year outcomes in infants born to mothers with and without NAFLD in pregnancy.

Nonalcoholic fatty liver disease (NAFLD) affects an estimated 17% of pregnant patients in the USA. However, there are limited data on the impact of maternal NAFLD on pediatric outcomes. We prospectively evaluated outcomes in infants born to mothers with and without NAFLD in pregnancy over their first 2 years of life. Maternal subjects were identified through an ongoing prospective study in which pregnant individuals were screened for NAFLD. Pediatric outcomes of infants born to these mothers-including adverse neonatal outcomes and weight and weight-for-length percentile at 6, 12, 18, and 24 months-were prospectively evaluated. Multivariate logistic regression was performed to evaluate the association of maternal NAFLD with pediatric outcomes, as well as to adjust for potentially confounding maternal characteristics. Six hundred thirty-eight infants were included in our cohort. The primary outcomes assessed were weight and growth throughout the first 2 years of life. Maternal NAFLD was also not associated with increased infant birth weight or weight-for-gestational-age percentile or weight or weight-for-length percentile over the first 2 years of life. Maternal NAFLD was significantly associated with very premature delivery before 32 weeks, even after adjustment for confounding maternal characteristics (aOR = 2.83, p = 0.05). Maternal NAFLD was also significantly associated with neonatal jaundice, including after adjusting for maternal race (aOR = 1.67, p = 0.03). However, maternal NAFLD was not significantly associated with any other adverse neonatal outcomes.    Conclusion: Maternal NAFLD may be independently associated with very premature birth and neonatal jaundice but was not associated with other adverse neonatal outcomes. Maternal NAFLD was also not associated with any differences in infant growth over the first 2 years of life. What is Known: • Maternal NAFLD in pregnancy may be associated with adverse pregnancy and neonatal outcomes, but the findings are inconsistent across the literature. What is New: • Maternal NAFLD is not associated with any differences in weight at birth or growth over the first 2 years of life. • Maternal NAFLD is associated with very premature delivery and neonatal jaundice, but is not associated with other adverse neonatal outcomes.

Single-cell transcriptomics reveals conserved cell identities and fibrogenic phenotypes in zebrafish and human liver.

The mechanisms underlying liver fibrosis are multifaceted and remain elusive with no approved antifibrotic treatments available. The adult zebrafish has been an underutilized tool to study liver fibrosis. We aimed to characterize the single-cell transcriptome of the adult zebrafish liver to determine its utility as a model for studying liver fibrosis. We used single-cell RNA sequencing (scRNA-seq) of adult zebrafish liver to study the molecular and cellular dynamics at a single-cell level. We performed a comparative analysis to scRNA-seq of human liver with a focus on hepatic stellate cells (HSCs), the driver cells in liver fibrosis. scRNA-seq reveals transcriptionally unique populations of hepatic cell types that comprise the zebrafish liver. Joint clustering with human liver scRNA-seq data demonstrates high conservation of transcriptional profiles and human marker genes in zebrafish. Human and zebrafish HSCs show conservation of transcriptional profiles, and we uncover collectin subfamily member 11 (colec11) as a novel, conserved marker for zebrafish HSCs. To demonstrate the power of scRNA-seq to study liver fibrosis using zebrafish, we performed scRNA-seq on our zebrafish model of a pediatric liver disease with mutation in mannose phosphate isomerase (MPI) and characteristic early liver fibrosis. We found fibrosis signaling pathways and upstream regulators conserved across MPI-depleted zebrafish and human HSCs. CellPhoneDB analysis of zebrafish transcriptome identified neuropilin 1 as a potential driver of liver fibrosis. Conclusion: This study establishes the first scRNA-seq atlas of the adult zebrafish liver, highlights the high degree of similarity to human liver, and strengthens its value as a model to study liver fibrosis.

Left lateral segment pediatric liver transplantation: a 25 year experience at Mount Sinai.

BACKGROUND: Outcomes of left lateral segment (LLS) grafts in pediatric recipients were compared between living (LD-LLS) and deceased donor (DD-LLS) grafts. METHODS: 195 LLS grafts (99DD-LLS-96LD-LLS) were analyzed with a median follow-up of 9.1years. The primary endpoints were overall patient/graft survival. RESULTS: LD-LLS grafts were younger (0.9vs.1.4years, p = 0.039), more likely to have a fulminant liver failure (17.9%vs.5.3%,p = 0.002), less likely to have a metabolic disorder (6.3%vs.25.5%,p = 0.002), and less likely to be undergoing retransplantation (5.3% vs.16.2%,p = 0.015). There was a trend toward decreased hepatic artery thrombosis in LD-LLS grafts (6.6% vs. 15.5%,p = 0.054). No differences in the overall biliary complications occurred. The LD-LLS group had prolonged survival compared to the DD-LLS group with 10-year survival rates of 81%, and 74% (p = 0.005), respectively. LD-LLS grafts had longer graft survival compared to DD-LLS grafts (10-year graft survival 85%vs.67%,p = 0.005). Recipient age >1year (HR 2.39,p = 0.026), aortic reconstruction (HR 2.12,p = 0.046) and vascular complication (HR 3.12,p < 0.001) were independent predictors of poor patient survival. Non-biliary liver disease (HR 2.17,p = 0.015), DD-LLS (HR 2.06,p = 0.034) and vascular complication (HR 4.61,p < 0.001) were independent predictors of poor graft survival. CONCLUSION: The use of SLT remains a viable option with excellent long-term outcomes. We show improved graft and patient survival with living donor grafts.

Impact of the Corona Virus Disease 2019 Pandemic on Hepatology Practice and Provider Burnout.

The corona virus disease 2019 (COVID-19) pandemic has had a wide-ranging impact on the clinical practice of medicine and emotional well-being of providers. Our aim was to determine the impact of the COVID-19 pandemic on practice and burnout among hepatology providers. From February to March 2021, we conducted an electronic survey of American Association for the Study of Liver Diseases (AASLD) members who were hepatologists, gastroenterologists, and advanced practice providers (APPs). The survey included 26 questions on clinical practice and emotional well-being derived from validated instruments. A total of 230 eligible members completed the survey as follows: 107 (47%) were adult transplant hepatologists, 43 (19%) were adult general hepatologists, 14 (6%) were adult gastroenterologists, 11 (5%) were pediatric hepatologists, 45 (19%) were APPs, and 9 (4%) were other providers. We found that 69 (30%) experienced a reduction in compensation, 92 (40%) experienced a reduction in staff, and 9 (4%) closed their practice; 100 (43%) respondents reported experiencing burnout. In univariate analysis, burnout was more frequently reported in those ≤55 years old (odds ratio [OR], 2.2; 95% confidence interval [CI], 1.2-4.2), women (OR, 2.2; 95% CI, 1.3-3.7), nontransplant hepatology (OR, 2.0; 95% CI, 1.1-3.3), APPs (OR, 2.7; 95% CI, 1.4-5.1), and those less than 10 years in practice (OR, 1.9; 95% CI, 1.1-3.3). In multivariable analysis, only age ≤55 years was associated with burnout (OR, 2.3; 95% CI, 1.1-4.8). The most common ways the respondents suggested the AASLD could help was through virtual platforms for networking, mentoring, and coping with the changes in practice due to the COVID-19 pandemic. Conclusion: The COVID-19 pandemic has had a substantial impact on the clinical practice of hepatology as well as burnout and emotional well-being. Women, APPs, and early and mid-career clinicians more frequently reported burnout. Identified strategies to cope with burnout include virtual platforms to facilitate networking and mentoring.

A myeloid-stromal niche and gp130 rescue in NOD2-driven Crohn's disease.

Crohn's disease is a chronic inflammatory intestinal disease that is frequently accompanied by aberrant healing and stricturing complications. Crosstalk between activated myeloid and stromal cells is critical in the pathogenicity of Crohn's disease1,2, and increases in intravasating monocytes are correlated with a lack of response to anti-TNF treatment3. The risk alleles with the highest effect on Crohn's disease are loss-of-function mutations in NOD24,5, which increase the risk of stricturing6. However, the mechanisms that underlie pathogenicity driven by NOD2 mutations and the pathways that might rescue a lack of response to anti-TNF treatment remain largely uncharacterized. Here we use direct ex vivo analyses of patients who carry risk alleles of NOD2 to show that loss of NOD2 leads to dysregulated homeostasis of activated fibroblasts and macrophages. CD14+ peripheral blood mononuclear cells from carriers of NOD2 risk alleles produce cells that express high levels of collagen, and elevation of conserved signatures is observed in nod2-deficient zebrafish models of intestinal injury. The enrichment of STAT3 regulation and gp130 ligands in activated fibroblasts and macrophages suggested that gp130 blockade might rescue the activated program in NOD2-deficient cells. We show that post-treatment induction of the STAT3 pathway is correlated with a lack of response to anti-TNF treatment in patients, and demonstrate in vivo in zebrafish the amelioration of the activated myeloid-stromal niche using the specific gp130 inhibitor bazedoxifene. Our results provide insights into NOD2-driven fibrosis in Crohn's disease, and suggest that gp130 blockade may benefit some patients with Crohn's disease-potentially as a complement to anti-TNF therapy.

American Association for the Study of Liver Diseases Expert Panel Consensus Statement: Vaccines to Prevent Coronavirus Disease 2019 Infection in Patients With Liver Disease.

The aim of this document is to provide a concise scientific review of the currently available COVID-19 vaccines and those in development, including mRNA, adenoviral vectors, and recombinant protein approaches. The anticipated use of COVID-19 vaccines in patients with chronic liver disease (CLD) and liver transplant (LT) recipients is reviewed and practical guidance is provided for health care providers involved in the care of patients with liver disease and LT about vaccine prioritization and administration. The Pfizer and Moderna mRNA COVID-19 vaccines are associated with a 94%-95% vaccine efficacy compared to placebo against COVID-19. Local site reactions of pain and tenderness were reported in 70%-90% of clinical trial participants, and systemic reactions of fever and fatigue were reported in 40%-70% of participants, but these reactions were generally mild and self-limited and occurred more frequently in younger persons. Severe hypersensitivity reactions related to the mRNA COVID-19 vaccines are rare and more commonly observed in women and persons with a history of previous drug reactions for unclear reasons. Because patients with advanced liver disease and immunosuppressed patients were excluded from the vaccine licensing trials, additional data regarding the safety and efficacy of COVID-19 vaccines are eagerly awaited in these and other subgroups. Remarkably safe and highly effective mRNA COVID-19 vaccines are now available for widespread use and should be given to all adult patients with CLD and LT recipients. The online companion document located at https://www.aasld.org/about-aasld/covid-19-resources will be updated as additional data become available regarding the safety and efficacy of other COVID-19 vaccines in development.

Clinical Research in Hepatology in the COVID-19 Pandemic and Post-Pandemic Era: Challenges and the Need for Innovation.

The severe acute respiratory syndrome coronavirus 2 pandemic has drastically altered all facets of clinical care and research. Clinical research in hepatology has had a rich tradition in several domains, including the discovery and therapeutic development for diseases such as hepatitis B and C and studying the natural history of many forms of chronic liver disease. National Institutes of Health, foundation, and industry funding have provided important opportunities to advance the academic careers of young investigators while they strived to make contributions to the field. Instantaneously, however, all nonessential research activities were halted when the pandemic started, forcing those involved in clinical research to rethink their research strategy, including a shift to coronavirus disease 2019 research while endeavoring to maintain their preexisting agenda. Strategies to maintain the integrity of ongoing studies, including patient follow-up, safety assessments, and continuation of investigational products, have included a shift to telemedicine, remote safety laboratory monitoring, and shipping of investigational products to study subjects. As a revamp of research is being planned, unique issues that face the research community include maintenance of infrastructure, funding, completion of studies in the predetermined time frame, and the need to reprogram career path timelines. Real-world databases, biomarker and long-term follow up studies, and research involving special groups (children, the homeless, and other marginalized populations) are likely to face unique challenges. The implementation of telemedicine has been dramatically accelerated and will serve as a backbone for the future of clinical research. As we move forward, innovation in clinical trial design will be essential for conducting optimized clinical research.

Zebrafish modeling of intestinal injury, bacterial exposures and medications defines epithelial in vivo responses relevant to human inflammatory bowel disease.

Genome-wide association studies have identified over 200 genomic loci associated with inflammatory bowel disease (IBD). High-effect risk alleles define key roles for genes involved in bacterial response and innate defense. More high-throughput in vivo systems are required to rapidly evaluate therapeutic agents. We visualize, in zebrafish, the effects on epithelial barrier function and intestinal autophagy of one-course and repetitive injury. Repetitive injury induces increased mortality, impaired recovery of intestinal barrier function, failure to contain bacteria within the intestine and impaired autophagy. Prostaglandin E2 (PGE2) administration protected against injury by enhancing epithelial barrier function and limiting systemic infection. Effects of IBD therapeutic agents were defined: mesalamine showed protective features during injury, whereas 6-mercaptopurine displayed marked induction of autophagy during recovery. Given the highly conserved nature of innate defense in zebrafish, it represents an ideal model system with which to test established and new IBD therapies targeted to the epithelial barrier.This article has an associated First Person interview with the first author of the paper.

Hepatotoxicity in Zebrafish Larvae.

Zebrafish (Danio rerio) larvae are a uniquely powerful model system which investigate the effects of toxicant exposure on liver development and function. Manufacturing processes and development of new synthetic compounds increased rapidly since the middle of the twentieth century, resulting in widespread exposure to environmental toxicants. This is compounded by the shift in the global burden of disease from infectious agents to chronic disease, particularly in industrialized nations, which increases the need to investigate the long-term and transgenerational effects of environmental exposures on human health. Zebrafish provide an excellent model to investigate the mechanisms of action of environmental pollutants given their large-scale embryo production and rapid development, which allow for short-term assessment of toxicity in a whole animal system. Here we describe methods for the use of zebrafish to study hepatotoxicity and liver disease induced by chemical toxicants. Many of the genetic, molecular, and cellular processes are conserved between zebrafish and mammals, enabling translation to human populations and diseases.

Mannose Phosphate Isomerase and Mannose Regulate Hepatic Stellate Cell Activation and Fibrosis in Zebrafish and Humans.

The growing burden of liver fibrosis and lack of effective antifibrotic therapies highlight the need for identification of pathways and complementary model systems of hepatic fibrosis. A rare, monogenic disorder in which children with mutations in mannose phosphate isomerase (MPI) develop liver fibrosis led us to explore the function of MPI and mannose metabolism in liver development and adult liver diseases. Herein, analyses of transcriptomic data from three human liver cohorts demonstrate that MPI gene expression is down-regulated proportionate to fibrosis in chronic liver diseases, including nonalcoholic fatty liver disease and hepatitis B virus. Depletion of MPI in zebrafish liver in vivo and in human hepatic stellate cell (HSC) lines in culture activates fibrotic responses, indicating that loss of MPI promotes HSC activation. We further demonstrate that mannose supplementation can attenuate HSC activation, leading to reduced fibrogenic activation in zebrafish, culture-activated HSCs, and in ethanol-activated HSCs. Conclusion: These data indicate the prospect that modulation of mannose metabolism pathways could reduce HSC activation and improve hepatic fibrosis.

Autoimmune hemolytic anemia: An unusual presentation of hemophagocytic lymphohistiocytosis in a pediatric post-liver transplant patient.

Hemophagocytic lymphohistiocytosis (HLH), a rare condition characterized by immune dysfunction with uncontrolled activation of macrophages and hypersecretion of cytokines, has only been reported in a small number of pediatric patients following solid organ transplant (SOT). The diagnosis of HLH after SOT is especially difficult, as several of the diagnostic criteria, including fever, splenomegaly, and cytopenias, are nonspecific and can be seen with other post-transplant complications. Autoimmune hemolytic anemia (AIHA) has also been reported after pediatric SOT and is thought to be related to immunosuppression, specifically tacrolimus. Although HLH and AIHA have been separately described following SOT, there have been no reports of them occurring together in post-liver transplant (LT) patients. We report the first case of autoimmune hemolysis as the presenting symptom of HLH in a pediatric post-LT patient.

Pediatric Liver Transplant Teams Coping With Patient Death.

OBJECTIVES: Coping with patient death among pediatric liver transplant teams has received little attention despite general recognition of the potentially negative emotional consequences associated with such loss. The purpose of this study was to investigate the ways in which members of pediatric liver transplant teams cope with the death of patients on the waitlist and post-transplant and the institutional resources available to facilitate this coping. METHODS: Participants included 120 physicians, nurses, and mental health professionals from multiple transplant centers across the United States. Participants completed an online questionnaire that assessed the availability of formal coping resources at their institutions, informal sources of support used to cope with patient death, and as indices of coping, bereavement, and emotional exhaustion symptoms experienced. RESULTS: Debriefing, the most commonly offered support, was available to about half (55.8%) of the sample; yet, nearly all respondents (98.3%) indicated that debriefing would be useful. On average, bereavement and emotional exhaustion levels were comparable to normative data, but patterns of coping varied based on participants' position within the transplant team. For participants who reported that debriefing was available at their institutions, emotional exhaustion was lower. CONCLUSIONS: Overall, formal supports were inconsistently offered to pediatric transplant team members. Team members expressed high acceptability for debriefing, which has been associated with benefits in other populations, and findings indicated better coping in the transplant setting when it was offered.

Inorganic arsenic causes fatty liver and interacts with ethanol to cause alcoholic liver disease in zebrafish.

The rapid increase in fatty liver disease (FLD) incidence is attributed largely to genetic and lifestyle factors; however, environmental toxicants are a frequently overlooked factor that can modify the effects of more common causes of FLD. Chronic exposure to inorganic arsenic (iAs) is associated with liver disease in humans and animal models, but neither the mechanism of action nor the combinatorial interaction with other disease-causing factors has been fully investigated. Here, we examined the contribution of iAs to FLD using zebrafish and tested the interaction with ethanol to cause alcoholic liver disease (ALD). We report that zebrafish exposed to iAs throughout development developed specific phenotypes beginning at 4 days post-fertilization (dpf), including the development of FLD in over 50% of larvae by 5 dpf. Comparative transcriptomic analysis of livers from larvae exposed to either iAs or ethanol revealed the oxidative stress response and the unfolded protein response (UPR) caused by endoplasmic reticulum (ER) stress as common pathways in both these models of FLD, suggesting that they target similar cellular processes. This was confirmed by our finding that arsenic is synthetically lethal with both ethanol and a well-characterized ER-stress-inducing agent (tunicamycin), suggesting that these exposures work together through UPR activation to cause iAs toxicity. Most significantly, combined exposure to sub-toxic concentrations of iAs and ethanol potentiated the expression of UPR-associated genes, cooperated to induce FLD, reduced the expression of as3mt, which encodes an arsenic-metabolizing enzyme, and significantly increased the concentration of iAs in the liver. This demonstrates that iAs exposure is sufficient to cause FLD and that low doses of iAs can potentiate the effects of ethanol to cause liver disease.This article has an associated First Person interview with the first author of the paper.

Pediatric liver transplantation for fulminant hepatic failure secondary to intentional iron overdose.

Acute iron poisoning may lead to life-threatening hepatotoxicity. We present the cases of two pediatric patients with hepatotoxicity following intentional iron ingestion that progressed rapidly to fulminant hepatic failure despite treatment with deferoxamine. Liver transplantation was lifesaving in both patients. These cases emphasize the need for a high index of suspicion for iron ingestion, close monitoring for liver toxicity, and timely consideration for liver transplantation.

MPI depletion enhances O-GlcNAcylation of p53 and suppresses the Warburg effect.

Rapid cellular proliferation in early development and cancer depends on glucose metabolism to fuel macromolecule biosynthesis. Metabolic enzymes are presumed regulators of this glycolysis-driven metabolic program, known as the Warburg effect; however, few have been identified. We uncover a previously unappreciated role for Mannose phosphate isomerase (MPI) as a metabolic enzyme required to maintain Warburg metabolism in zebrafish embryos and in both primary and malignant mammalian cells. The functional consequences of MPI loss are striking: glycolysis is blocked and cells die. These phenotypes are caused by induction of p53 and accumulation of the glycolytic intermediate fructose 6-phosphate, leading to engagement of the hexosamine biosynthetic pathway (HBP), increased O-GlcNAcylation, and p53 stabilization. Inhibiting the HBP through genetic and chemical methods reverses p53 stabilization and rescues the Mpi-deficient phenotype. This work provides mechanistic evidence by which MPI loss induces p53, and identifies MPI as a novel regulator of p53 and Warburg metabolism.