Pediatric metabolic (dysfunction)-associated fatty liver disease: current insights and future perspectives.

The historical use of the term non-alcoholic fatty liver disease (NAFLD) in obese/overweight children has been controversial as to the appropriateness of this terminology in children, and lately, in adults too. Newer game-changer terminology, metabolic (dysfunction)-associated fatty liver disease (MAFLD), for this condition signifies a positive step forward that addresses the limitations of the previous definition for both adults and children. The prevalence of MAFLD has surged in tandem with the global rise in obesity rates, establishing itself as a predominant cause of chronic liver disease in both adult and pediatric populations. The adoption of the recently proposed nomenclature reflects a more encompassing comprehension of the disease and its etiology compared to its predecessor, NAFLD. Notably, the revised terminology facilitates the recognition of MAFLD as an autonomous condition while acknowledging the potential coexistence of other systemic fatty liver disorders. Particularly in children, this includes various paediatric-onset genetic and inherited metabolic disorders, necessitating thorough exclusion, especially in cases where weight loss interventions yield no improvement or in the absence of obesity. MAFLD presents as a multifaceted disorder; evidence suggests its origins lie in a complex interplay of nutritional, genetic, hormonal, and environmental factors. Despite advancements, current non-invasive diagnostic biomarkers exhibit limitations in accuracy, often necessitating imaging and histological evaluations for definitive diagnosis. While dietary and lifestyle modifications stand as cornerstone measures for MAFLD prevention and management, ongoing evaluation of therapeutic agents continues. This article provides an overview of the latest developments and emerging therapies in the realm of paediatric MAFLD.

An international, multicenter, survey-based analysis of practice and management of acute liver failure.

Acute liver failure (ALF) is an acute liver dysfunction with coagulopathy and HE in a patient with no known liver disease. As ALF is rare and large clinical trials are lacking, the level of evidence regarding its management is low-moderate, favoring heterogeneous clinical practice. In this international multicenter survey study, we aimed to investigate the current practice and management of patients with ALF. An online survey targeting physicians who care for patients with ALF was developed by the International Liver Transplantation Society ALF Special-Interest Group. The survey focused on the management and liver transplantation (LT) practices of ALF. Survey questions were summarized overall and by geographic region. A total of 267 physicians completed the survey, with a survey response rate of 21.36%. Centers from all continents were represented. More than 90% of physicians specialized in either transplant hepatology/surgery or anesthesiology/critical care. Two hundred fifty-two (94.4%) respondents' institutions offered LT. A total of 76.8% of respondents' centers had a dedicated liver-intensive or transplant-intensive care unit ( p < 0.001). The median time to LT was within 48 hours in 12.7% of respondents' centers, 72 hours in 35.6%, 1 week in 37.6%, and more than 1 week in 9.6% ( p < 0.001). Deceased donor liver graft (49.6%) was the most common type of graft offered. For consideration of LT, 84.8% of physicians used King's College Criteria, and 41.6% used Clichy Criteria. Significant differences were observed between Asia, Europe, and North America for offering LT, number of LTs performed, volume of patients with ALF, admission to a dedicated intensive care unit, median time to LT, type of liver graft, monitoring HE and intracranial pressure, management of coagulopathy, and utilization of different criteria for LT. In our study, we observed significant geographic differences in the practice and management of ALF. As ALF is rare, multicenter studies are valuable for identifying global practice.

Preclinical efficacy and safety of encapsulated proliferating human hepatocyte organoids in treating liver failure.

Alginate-encapsulated hepatocyte transplantation is a promising strategy to treat liver failure. However, its clinical application was impeded by the lack of primary human hepatocytes and difficulty in controlling their quality. We previously reported proliferating human hepatocytes (ProliHHs). Here, quality-controlled ProliHHs were produced in mass and engineered as liver organoids to improve their maturity. Encapsulated ProliHHs liver organoids (eLO) were intraperitoneally transplanted to treat liver failure animals. Notably, eLO treatment increased the survival of mice with post-hepatectomy liver failure (PHLF) and ameliorated hyperammonemia and hypoglycemia by providing liver functions. Additionally, eLO treatment protected the gut from PHLF-augmented permeability and normalized the increased serum endotoxin and inflammatory response, which facilitated liver regeneration. The therapeutic effect of eLO was additionally proved in acetaminophen-induced liver failure. Furthermore, we performed assessments of toxicity and biodistribution, demonstrating that eLO had no adverse effects on animals and remained non-tumorigenic.

Efficacy and safety of onasemnogene abeparvovec in children with spinal muscular atrophy type 1: real-world evidence from 6 infusion centres in the United Kingdom.

Background: Real-world data on the efficacy and safety of onasemnogene abeparvovec (OA) in spinal muscular atrophy (SMA) are needed, especially to overcome uncertainties around its use in older and heavier children. This study evaluated the efficacy and safety of OA in patients with SMA type 1 in the UK, including patients ≥2 years old and weighing ≥13.5 kg. Methods: This observational cohort study used data from patients with genetically confirmed SMA type 1 treated with OA between May 2021 and January 2023, at 6 infusion centres in the United Kingdom. Functional outcomes were assessed using age-appropriate functional scales. Safety analyses included review of liver function, platelet count, cardiac assessments, and steroid requirements. Findings: Ninety-nine patients (45 SMA therapy-naïve) were treated with OA (median age at infusion: 10 [range, 0.6-89] months; median weight: 7.86 [range, 3.2-20.2] kg; duration of follow-up: 3-22 months). After OA infusion, mean ± SD change in CHOP-INTEND score was 11.0 ± 10.3 with increased score in 66/78 patients (84.6%); patients aged <6 months had a 13.9 points higher gain in CHOP-INTEND score than patients ≥2 years (95% CI, 6.8-21.0; P < 0.001). Asymptomatic thrombocytopenia (71/99 patients; 71.7%), asymptomatic troponin-I elevation (30/89 patients; 33.7%) and transaminitis (87/99 patients; 87.9%) were reported. No thrombotic microangiopathy was observed. Median steroid treatment duration was 97 (range, 28-548) days with dose doubled in 35/99 patients (35.4%). There were 22.5-fold increased odds of having a transaminase peak >100 U/L (95% CI, 2.3-223.7; P = 0.008) and 21.2-fold increased odds of steroid doubling, as per treatment protocol (95% CI, 2.2-209.2; P = 0.009) in patients weighing ≥13.5 kg versus <8.5 kg. Weight at infusion was positively correlated with steroid treatment duration (r = 0.43; P < 0.001). Worsening transaminitis, despite doubling of oral prednisolone, led to treatment with intravenous methylprednisolone in 5 children. Steroid-sparing immunosuppressants were used in 5 children to enable steroid weaning. Two deaths apparently unrelated to OA were reported. Interpretation: OA led to functional improvements and was well tolerated with no persistent clinical complications, including in older and heavier patients. Funding: Novartis Innovative Therapies AG provided a grant for independent medical writing services.

Human Hepatocyte Transplantation: Three Decades of Clinical Experience and Future Perspective.

Orthotopic liver transplantation (OLT) is the current standard of care for both chronic and acute terminal liver disease. However, a major limitation of this treatment is the shortage of healthy donor organs and the need for life-long immunosuppression to prevent graft rejection. Hepatocyte transplantation (HTx) has emerged as a promising, alternative therapeutic approach to either replace OLT or to act as a bridge until a donor liver becomes available thus reducing waiting list mortality. HTx involves the infusion and engraftment of human hepatocytes, typically isolated from organs unsuitable for OLT, into recipient liver parenchyma to carry out the missing hepatic function of the native cells. HTx is less invasive than OLT and can be performed repeatedly if required. The safety of clinical HTx has been shown and treatment results are promising, especially in patients with liver-based metabolic disorders. Nevertheless, HTx has failed to become the standard of care treatment for such disorders. This review aims to evaluate the progress that has been made within the field of HTx over the last 30 years and identify potential shortcomings within the approach which may be hindering its routine clinical application.

Pediatric Liver Transplantation: Selection Criteria and Post-transplant Medical Management.

Pediatric liver transplantation remains the gold standard for life-threatening acute and chronic liver diseases and multiple liver-based inherited metabolic defects. Advances in surgical techniques, better perioperative care and immunosuppression regimes have resulted in excellent long-term graft and patient survival. The success of pediatric liver transplantation does however bring the additional challenge of long-term patient outcomes including graft hepatitis-related fibrosis and suboptimal biopsychosocial outcomes. In this review, authors will explore the current landscape of pediatric liver transplantation including indications, timing of referral for liver transplantation, surgical techniques and long-term outcomes such as recurrence of pre-transplant liver disease, idiopathic graft hepatitis and biopsychosocial outcomes. Ultimately, early identification and management of potential issues long-term helps ensure our recipients achieve a "meaningful survival".

Transient elastography and von Willebrand factor as predictors of portal hypertension and decompensation in children.

Background & Aims: Von Willebrand factor antigen (vWFAg), a protein measured to test the level of vWF released from the vascular endothelium has gained much attention as a marker for portal hypertension (PHT) severity. The objectives of this study were to investigate the use of vWFAg as a biomarker along with liver and spleen stiffness measurements by transient elastography as potential predictors of clinically significant varices (CSV), variceal bleeding (VB) and decompensation in children with PHT. Methods: This observational prospective cohort study included 117 children (median age 10 [IQR 6-14] years) who underwent oesophagogastroduodenoscopy between January'2012 to November'2021 and a validation group of 33 children who underwent the same procedure between December'2021 to March'2023. Measurements of vWFAg and glycoprotein Ib binding activity of VWF (GPIbR) were available in 97 patients in the study group and in all patients in the validation group.Results: vWFAg and GPIbR were significantly higher in children with CSV (223 IU/dl and 166 IU/dl; p = 0.015 and p = 0.04, respectively) and VB (218 IU/dl and 174 IU/dl; p = 0.077 and p = 0.03, respectively) than in those without CSV or VB, respectively. Ninety-six patients had liver and spleen stiffness measurements. Spleen stiffness was significantly higher in patients with CSV compared to those without CSV (p = 0.003). In a chronic liver disease subgroup, a predictive scoring tool based on vWFAg, GPIbR, platelet count, and spleen/liver stiffness measurements could predict CSV with an AUROC of 0.76 (p = 0.04). Conclusions: This study suggests the predictive value of vWF for CSV and VB increases when combined with spleen stiffness, with AUROCs of 0.88 and 0.82, respectively. Hence, a combination of biomarkers could assist clinicians in diagnosing CSV, preventing unnecessary invasive procedures. Impacts and implications: Surveillance endoscopies in children with portal hypertension (PHT) have their own risks and non-invasive markers, such as von Willebrand factor antigen, glycoprotein Ib binding activity of VWF (GPIbR), and transient elastography could be used to predict clinically significant varices, variceal bleeding and disease compensation in children with PHT. Such non-invasive markers for PHT and varices are lacking in the paediatric population. The results show that von Willebrand factor and GPIbR along with transient elastography can be used to formulate a scoring system which can be used as a clinical tool by paediatric hepatologists to monitor the progression of PHT and risk of bleeding, and hence to stratify the performance of invasive endoscopic procedures under general anaesthesia. However, there is a need to validate the scoring system in children with portal vein thrombosis and for hepatic decompensation in a multi-centre registry in the future.

Liver transplantation in ornithine transcarbamylase deficiency: A retrospective multicentre cohort study.

Ornithine transcarbamylase deficiency (OTCD) is an X-linked defect of ureagenesis and the most common urea cycle disorder. Patients present with hyperammonemia causing neurological symptoms, which can lead to coma and death. Liver transplantation (LT) is the only curative therapy, but has several limitations including organ shortage, significant morbidity and requirement of lifelong immunosuppression. This study aims to identify the characteristics and outcomes of patients who underwent LT for OTCD. We conducted a retrospective study for OTCD patients from 5 UK centres receiving LT in 3 transplantation centres between 2010 and 2022. Patients' demographics, family history, initial presentation, age at LT, graft type and pre- and post-LT clinical, metabolic, and neurocognitive profile were collected from medical records. A total of 20 OTCD patients (11 males, 9 females) were enrolled in this study. 6/20 had neonatal and 14/20 late-onset presentation. 2/20 patients had positive family history for OTCD and one of them was diagnosed antenatally and received prospective treatment. All patients were managed with standard of care based on protein-restricted diet, ammonia scavengers and supplementation with arginine and/or citrulline before LT. 15/20 patients had neurodevelopmental problems before LT. The indication for LT was presence (or family history) of recurrent metabolic decompensations occurring despite standard medical therapy leading to neurodisability and quality of life impairment. Median age at LT was 10.5 months (6-24) and 66 months (35-156) in neonatal and late onset patients, respectively. 15/20 patients had deceased donor LT (DDLT) and 5/20 had living related donor LT (LDLT). Overall survival was 95% with one patient dying 6 h after LT. 13/20 had complications after LT and 2/20 patients required re-transplantation. All patients discontinued dietary restriction and ammonia scavengers after LT and remained metabolically stable. Patients who had neurodevelopmental problems before LT persisted to have difficulties after LT. 1/5 patients who was reported to have normal neurodevelopment before LT developed behavioural problems after LT, while the remaining 4 maintained their abilities without any reported issues. LT was found to be effective in correcting the metabolic defect, eliminates the risk of hyperammonemia and prolongs patients' survival.

Pancreatitis in RYR1-related disorders.

Mutations in RYR1 encoding the ryanodine receptor (RyR) skeletal muscle isoform (RyR1) are a common cause of inherited neuromuscular disorders. Despite its expression in a wide range of tissues, non-skeletal muscle manifestations associated with RYR1 mutations have only been rarely reported. Here, we report three patients with a diagnosis of Central Core Disease (CCD), King-Denborough Syndrome (KDS) and Malignant Hyperthermia Susceptibility (MHS), respectively, who in addition to their (putative) RYR1-related disorder also developed symptoms and signs of acute pancreatitis. In two patients, episodes were recurrent, with severe multisystem involvement and sequelae. RyR1-mediated calcium signalling plays an important role in normal pancreatic function but has also been critically implicated in the pathophysiology of acute pancreatitis, particularly in bile acid- and ethanol-induced forms. Findings from relevant animal models indicate that pancreatic damage in these conditions may be ameliorated through administration of the specific RyR1 antagonist dantrolene and other compounds modifying pancreatic metabolism including calcium signalling. These observations suggest that patients with RYR1 gain-of-function variants may be at increased risk of developing acute pancreatitis, a condition which should therefore be considered in the health surveillance of such individuals.

Medium-chain triglycerides and the impact on fat absorption, growth, nutritional status and clinical outcomes in children with cholestatic liver disease: A scoping review.

BACKGROUND & AIMS: Medium-chain triglyceride (MCT) supplementation is recommended in cholestatic liver disease, despite unclear evidence and no consensus on the ideal percentage of fat that should be MCT. The aim was to undertake a scoping review to identify the extent and type of evidence regarding how MCT supplementation, and percentage of MCT, affects fat absorption, growth, nutritional status and clinical outcomes (morbidity, mortality, transplant) in children with cholestatic liver disease. METHODS: Nine databases (MEDLINE, Embase, CINAHL, PubMed, AMED, Cochrane Library, Global Health, Scopus, Proquest) were searched from inception, with hand-searching conference abstracts and forward/backward citation searching. Eligible studies investigated oral/enteral MCT supplementation in children under 18y with cholestatic liver disease. There were no language limits. Two reviewers performed screening and data extraction independently. Data were synthesised narratively. RESULTS: Following title/abstract screening (1202 studies) and full-text review (40 studies), 24 studies were included comprising three small RCTs (n = 19 patients), one non-randomised controlled trial (n = 2), seven uncontrolled trials (n = 83) and thirteen case series/reports (n = 211). Seventeen studies were published before 1994. Outcomes included absorption, growth and nutritional status. MCT supplementation was associated with greater fat absorption (9/9 studies) and improved growth in some children (2/4). Higher percentage MCT was associated with greater magnesium and calcium absorption (1/1), essential fatty acid (EFA) deficiency (4/4), but not growth (3/3). CONCLUSIONS: The limited, mostly observational evidence from >30 years ago points to greater fat absorption on MCT and EFA deficiency on very high percentage MCT. High quality RCTs are required, particularly examining the impact of MCT at different percentages on growth, nutritional status and clinical outcomes.

Biliary atresia is associated with polygenic susceptibility in ciliogenesis and planar polarity effector genes.

BACKGROUND & AIMS: Biliary atresia (BA) is poorly understood and leads to liver transplantation (LT), with the requirement for and associated risks of lifelong immunosuppression, in most children. We performed a genome-wide association study (GWAS) to determine the genetic basis of BA. METHODS: We performed a GWAS in 811 European BA cases treated with LT in US, Canadian and UK centers, and 4,654 genetically matched controls. Whole-genome sequencing of 100 cases evaluated synthetic association with rare variants. Functional studies included whole liver transcriptome analysis of 64 BA cases and perturbations in experimental models. RESULTS: A GWAS of common single nucleotide polymorphisms (SNPs), i.e. allele frequencies >1%, identified intronic SNPs rs6446628 in AFAP1 with genome-wide significance (p = 3.93E-8) and rs34599046 in TUSC3 at sub-threshold genome-wide significance (p = 1.34E-7), both supported by credible peaks of neighboring SNPs. Like other previously reported BA-associated genes, AFAP1 and TUSC3 are ciliogenesis and planar polarity effectors (CPLANE). In gene-set-based GWAS, BA was associated with 6,005 SNPs in 102 CPLANE genes (p = 5.84E-15). Compared with non-CPLANE genes, more CPLANE genes harbored rare variants (allele frequency <1%) that were assigned Human Phenotype Ontology terms related to hepatobiliary anomalies by predictive algorithms, 87% vs. 40%, p <0.0001. Rare variants were present in multiple genes distinct from those with BA-associated common variants in most BA cases. AFAP1 and TUSC3 knockdown blocked ciliogenesis in mouse tracheal cells. Inhibition of ciliogenesis caused biliary dysgenesis in zebrafish. AFAP1 and TUSC3 were expressed in fetal liver organoids, as well as fetal and BA livers, but not in normal or disease-control livers. Integrative analysis of BA-associated variants and liver transcripts revealed abnormal vasculogenesis and epithelial tube formation, explaining portal vein anomalies that co-exist with BA. CONCLUSIONS: BA is associated with polygenic susceptibility in CPLANE genes. Rare variants contribute to polygenic risk in vulnerable pathways via unique genes. IMPACT AND IMPLICATIONS: Liver transplantation is needed to cure most children born with biliary atresia, a poorly understood rare disease. Transplant immunosuppression increases the likelihood of life-threatening infections and cancers. To improve care by preventing this disease and its progression to transplantation, we examined its genetic basis. We find that this disease is associated with both common and rare mutations in highly specialized genes which maintain normal communication and movement of cells, and their organization into bile ducts and blood vessels during early development of the human embryo. Because defects in these genes also cause other birth defects, our findings could lead to preventive strategies to lower the incidence of biliary atresia and potentially other birth defects.

Intraperitoneal transplant of Hepatocytes co-Encapsulated with mesenchymal stromal cells in modified alginate microbeads for the treatment of acute Liver failure in Pediatric patients (HELP)-An open-label, single-arm Simon's two stage phase 1 study protocol.

BACKGROUND: Pediatric acute liver failure (PALF) carries a high mortality without liver transplantation (LT) in children. Liver transplantation, though lifesaving, is limited by timely donor organ availability, the risks of major surgery and complications of life-long immunosuppression. Hepatocyte transplantation (HT) improves synthetic and detoxification functions in small animal models. The encapsulation of hepatocytes in alginate protects it from the recipient immune system while the intraperitoneal route of administration allows large volumes to be infused. The safety and possibly short-term efficacy of encapsulated hepatocytes has been observed in a named patient use. A novel type of microbeads (HMB002) has been developed, using a modified alginate and mesenchymal stromal cells (MSCs). Its safety and medium-term efficacy need to be studied in the context of clinical study while optimizing the hepatocyte function and viability using modifications of the alginate and MSCs co-encapsulation. METHODS: A single centre, non-randomised, open-label, single-arm Simon's two stage study will be conducted to evaluate the safety, biological activity and tolerability of transplantation of a single intraperitoneal dose of microbeads made from an optimum combination of a modified alginate, MSCs and hepatocytes in 17 patients less than 16 years of age with acute liver failure (Stage 1: 9 patients and Stage 2: 8 patient). Safety will be assessed by documenting moderate to severe (including life threatening and death) adverse events due to HMB002 in the first 52 weeks post-procedure. Tolerability will be assessed by observing the proportion of initiated infusions where >80% of infusion is received by the patient. Biological activity will be reflected in patient survival with native liver at 24 weeks post treatment. DISCUSSION: HMB002, if safe and efficacious in acute liver failure, could be a bridge until the liver regenerates or a suitable organ becomes available. There are multiple advantages to using HT. HT, when delivered by the intraperitoneal route, is less invasive than LT. Hepatocytes from a single donor liver can be used to treat multiple patients. Cryopreserved cells provide an off-the-shelf emergency treatment in PALF. When encapsulated, alginate encapsulation of hepatocytes precludes the need for immunosuppression unlike in LT.

Epidemiology and Risk Factors for Viral Infections in Pediatric Liver Transplant Recipients and Impact on Outcome.

Infections after liver transplantation (LT) are risk factors for morbidity and mortality. Infections, especially of viral etiologies, still have an impact on the graft function and overall outcome. The aim was to review the epidemiology and risk factors of EBV, CMV and non-EBV non-CMV viral infections and their impacts on outcomes after LT. Demographic, clinical, and laboratory data were retrieved from patients' electronic databases. Over 2 years, 96 patients were transplanted at the Pediatric Liver Centre at Kings College Hospital. The majority of the infections were of viral origin; 73 (76%) patients. The incidence of EBV viremia was 60.4%, CMV infection 35.4%, and other viruses 30%. Older donor age, auxiliary graft, and bacterial infections were risk factors for EBV infection. Younger recipient age, D+R- CMV IgG, and left lateral segment graft were risk factors for CMV infection. More than 70% of patients with non-EBV and CMV viral infections stayed positive post-LT but did not contribute to increased complications. Despite the high prevalence of viral infections, EBV, CMV, and non-EBV non-CMV viral infections were not associated with rejection, morbidity, or mortality. Although some of the risk factors for viral infections are unavoidable, identifying the characteristics and risk pattern will help improve the care for pediatric LT recipients.

Evaluation of living donors for hereditary liver disease (siblings, heterozygotes).

Living donor liver transplantation (LDLT) is recognised as an alternative treatment modality to reduce waiting list mortality and expand the donor pool. Over recent decades, there have been an increasing number of reports on the use of LT and specifically LDLT for familial hereditary liver diseases. There are marginal indications and contraindications that should be considered for a living donor in paediatric parental LDLT. No mortality or morbidity related to recurrence of metabolic diseases has been observed with heterozygous donors, except for certain relevant cases, such as ornithine transcarbamylase deficiency, protein C deficiency, hypercholesterolemia, protoporphyria, and Alagille syndrome, while donor human leukocyte antigen homozygosity also poses a risk. It is not always essential to perform preoperative genetic assays for possible heterozygous carriers; however, genetic and enzymatic assays must hereafter be included in the parental donor selection criteria in the aforementioned circumstances.