Event-free survival of maralixibat-treated patients with Alagille syndrome compared to a real-world cohort from GALA.

BACKGROUND AND AIMS: Alagille syndrome (ALGS) is characterized by chronic cholestasis with associated pruritus and extrahepatic anomalies. Maralixibat, an ileal bile acid transporter inhibitor, is an approved pharmacologic therapy for cholestatic pruritus in ALGS. Since long-term placebo-controlled studies are not feasible or ethical in children with rare diseases, a novel approach was taken comparing 6-year outcomes from maralixibat trials with an aligned and harmonized natural history cohort from the G lobal AL agille A lliance (GALA) study. APPROACH AND RESULTS: Maralixibat trials comprise 84 patients with ALGS with up to 6 years of treatment. GALA contains retrospective data from 1438 participants. GALA was filtered to align with key maralixibat eligibility criteria, yielding 469 participants. Serum bile acids could not be included in the GALA filtering criteria as these are not routinely performed in clinical practice. Index time was determined through maximum likelihood estimation in an effort to align the disease severity between the two cohorts with the initiation of maralixibat. Event-free survival, defined as the time to first event of manifestations of portal hypertension (variceal bleeding, ascites requiring therapy), surgical biliary diversion, liver transplant, or death, was analyzed by Cox proportional hazards methods. Sensitivity analyses and adjustments for covariates were applied. Age, total bilirubin, gamma-glutamyl transferase, and alanine aminotransferase were balanced between groups with no statistical differences. Event-free survival in the maralixibat cohort was significantly better than the GALA cohort (HR, 0.305; 95% CI, 0.189-0.491; p <0.0001). Multiple sensitivity and subgroup analyses (including serum bile acid availability) showed similar findings. CONCLUSIONS: This study demonstrates a novel application of a robust statistical method to evaluate outcomes in long-term intervention studies where placebo comparisons are not feasible, providing wide application for rare diseases. This comparison with real-world natural history data suggests that maralixibat improves event-free survival in patients with ALGS.

Prevalence, management and efficacy of treatment in portal vein obstruction after paediatric liver transplantation: protocol of the retrospective international multicentre PORTAL registry.

INTRODUCTION: Portal vein obstruction (PVO) consists of anastomotic stenosis and thrombosis, which occurs due to a progression of the former. The aim of this large-scale international study is to assess the prevalence, current management practices and efficacy of treatment in patients with PVO. METHODS AND ANALYSIS: The Portal vein Obstruction Revascularisation Therapy After Liver transplantation registry will facilitate an international, retrospective, multicentre, observational study, with 25 centres around the world already actively involved. Paediatric patients (aged <18 years) with a diagnosed PVO between 1 January 2001 and 1 January 2021 after liver transplantation will be eligible for inclusion. The primary endpoints are the prevalence of PVO, primary and secondary patency after PVO intervention and current management practices. Secondary endpoints are patient and graft survival, severe complications of PVO and technical success of revascularisation techniques. ETHICS AND DISSEMINATION: Medical Ethics Review Board of the University Medical Center Groningen has approved the study (METc 2021/072). The results of this study will be disseminated via peer-reviewed publications and scientific presentations at national and international conferences. TRIAL REGISTRATION NUMBER: Netherlands Trial Register (NL9261).

Natural history of liver disease in a large international cohort of children with Alagille syndrome: Results from the GALA study.

BACKGROUND AND AIMS: Alagille syndrome (ALGS) is a multisystem disorder, characterized by cholestasis. Existing outcome data are largely derived from tertiary centers, and real-world data are lacking. This study aimed to elucidate the natural history of liver disease in a contemporary, international cohort of children with ALGS. APPROACH AND RESULTS: This was a multicenter retrospective study of children with a clinically and/or genetically confirmed ALGS diagnosis, born between January 1997 and August 2019. Native liver survival (NLS) and event-free survival rates were assessed. Cox models were constructed to identify early biochemical predictors of clinically evident portal hypertension (CEPH) and NLS. In total, 1433 children (57% male) from 67 centers in 29 countries were included. The 10 and 18-year NLS rates were 54.4% and 40.3%. By 10 and 18 years, 51.5% and 66.0% of children with ALGS experienced ≥1 adverse liver-related event (CEPH, transplant, or death). Children (>6 and ≤12 months) with median total bilirubin (TB) levels between ≥5.0 and <10.0 mg/dl had a 4.1-fold (95% confidence interval [CI], 1.6-10.8), and those ≥10.0 mg/dl had an 8.0-fold (95% CI, 3.4-18.4) increased risk of developing CEPH compared with those <5.0 mg/dl. Median TB levels between ≥5.0 and <10.0 mg/dl and >10.0 mg/dl were associated with a 4.8 (95% CI, 2.4-9.7) and 15.6 (95% CI, 8.7-28.2) increased risk of transplantation relative to <5.0 mg/dl. Median TB <5.0 mg/dl were associated with higher NLS rates relative to ≥5.0 mg/dl, with 79% reaching adulthood with native liver ( p < 0.001). CONCLUSIONS: In this large international cohort of ALGS, only 40.3% of children reach adulthood with their native liver. A TB <5.0 mg/dl between 6 and 12 months of age is associated with better hepatic outcomes. These thresholds provide clinicians with an objective tool to assist with clinical decision-making and in the evaluation of therapies.

Use and safety of prophylactic endoscopy from a single center serving urban and rural children with portal hypertension.

Prophylactic endoscopy is routine in adults with portal hypertension (PHTN), but there is limited data in pediatrics. We sought to describe our experience with prophylactic endoscopy in pediatric PHTN. This is a retrospective study of 87 children who began surveillance endoscopy prior to gastrointestinal bleeding (primary prophylaxis) and 52 who began after an episode of bleeding (secondary prophylaxis) from 01/01/1994 to 07/01/2019. Patients who underwent primary prophylaxis had a lower mean number of endoscopies (3.897 vs 6.269, p = 0.001). The primary prophylaxis group was less likely to require a portosystemic shunt (6% vs 15%, p < 0.001) with no difference in immediate complications (1% vs 2%, p = 0.173) or 2-week complications (1% vs 2%, p = 0.097). No deaths were related to variceal bleeding or endoscopy. Kaplan-Meier Survival Curve suggests improved transplant and shunt free survival in the primary prophylaxis group (log-rank p < 0.001). Primary and secondary endoscopic prophylaxis should be considered safe for the prevention of variceal hemorrhage in pediatric portal hypertension. There are differences in outcomes in primary and secondary prophylaxis, but unclear if this is due to patient characteristics versus treatment strategy. Further study is needed to compare safety and efficacy to watchful waiting.

Readiness to Change and Prospective Effects of Weight Management Programs in Pediatric Nonalcoholic Fatty Liver Disease.

Non-alcoholic fatty liver disease (NAFLD) is an increasing problem in pediatrics with limited treatment options. We prospectively assessed outcomes in patients managed in a hepatology clinic (HC) alone vs. those managed in combination with a multidisciplinary weight management program (MWMP). We describe each group's readiness to change at the time of NAFLD diagnosis. Patients diagnosed with NAFLD were given a modified Stages of Change Readiness and Treatment Eagerness Scale (SOCRATES) at enrollment (T1) to assess readiness to change. They were then followed at 3-9 months (T2) and at 10-15 months (T3). Linear mixed models were used to evaluate changes in body mass index (BMI), BMI z-score, and transaminases over time and between the two groups. There were no significant treatment group main effects or treatment × time interactions for our primary end points for HC alone (n = 75) or with MWMP (n = 18). There was a significant main effect for time for BMI z-score, with BMI z-scores declining on average by 0.0568 (P = 0.004) from visit to visit. Low SOCRATES subscales scores in HC alone (n = 33) or with MWMP (n = 4) suggested a patient population with low recognition of disease and likelihood of taking steps for change. Patients with obesity and NAFLD had low scores on all three SOCRATES subscales. Despite this, both groups had improvement in BMI z-score without significant difference between the two treatment groups in other primary end points. Further study is needed to identify the most effective patient selection and treatment strategies for pediatric patients with NAFLD, including pharmacotherapy and surgery.

Complications of Cryptosporidium infection after pediatric liver transplantation: Diarrhea, rejection, and biliary disease.

BACKGROUND: Cryptosporidium enteritis can be devastating in the immunocompromised host. In pediatric liver transplant recipients, infection may be complicated by prolonged carriage of the parasite, rejection, and biliary tree damage and fibrosis. Herein, we report on six patients and their long-term outcomes following cryptosporidiosis. METHODS: We reviewed all cases of cryptosporidiosis in a pediatric liver transplant population over a 17-year period at a single center. Six patients with infection were identified, and their outcomes were analyzed. RESULTS: Infection was associated with significant diarrhea and dehydration in all cases, and led to hospitalization in one-half of patients. Four of the six patients developed biopsy-proven rejection following infection, with three of those patients developing rejection that was recalcitrant to intravenous steroid treatment. Additionally, three patients developed biliary tree abnormalities with similarity to sclerosing cholangitis. In one patient, those biliary changes led to repeated need for biliary drain placement and advancing fibrotic liver allograft changes. CONCLUSIONS: Cryptosporidiosis in pediatric liver transplant recipients may lead to significant complications, including recalcitrant episodes of rejection and detrimental biliary tree changes. We advocate for increased awareness of this cause of diarrheal disease and the allograft injuries that may accompany infection.

Conservative Management of Pneumatosis Intestinalis and Portal Venous Gas After Pediatric Liver Transplantation.

BACKGROUND: Pneumatosis intestinalis (PI) is a rare pathologic finding in pediatric liver transplant (PLT) recipients. The presentation and course of PI can range from asymptomatic and clinically benign to life threatening, with no consensus regarding management of PI in children. We aim to review the clinical presentation and radiologic features of PLT recipients with PI and to report the results of conservative management. METHODS: A retrospective medical chart review was conducted on PLT recipients between November 1995 and May 2016. Parameters evaluated at PI diagnosis included pneumatosis location, presence of free air or portal venous gas (PVG), symptoms, laboratory findings, and medication regimen. RESULTS: PI developed in 10 of 130 PLT patients (7.7%) between 8 days and 7 years (median: 113 days) posttransplant. Five of the patients were male, and the median age was 2 years (range, 1-17 years). PI was located in 1 to 2 abdominal quadrants in 6 patients, and 3 patients had PVG. At diagnosis, all patients were on steroids and immunosuppressant medication and 6 patients had a concurrent infection. Laboratory findings were unremarkable. Symptoms were present in 7 patients. Nine patients were managed conservatively, and 1 patient received observation only. All patients had resolution of PI at a median of 7 days (range, 2-14 days). CONCLUSIONS: PI can occur at any time after PLT and appears to be associated with steroid use and infectious agents. If PI/PVG is identified and the patient is clinically stable, initiation of a standard management algorithm may help treat these patients conservatively, thus avoiding surgical intervention.

The impact of thromboelastography on resuscitation in pediatric liver transplantation.

Although TEG directs effective resuscitation in adult surgical patients, pediatric data are lacking. We performed a retrospective comparative review of the effect of TEG on blood product utilization and outcomes following pediatric liver transplantation in 38 patients between 2008 and 2014. Diagnoses, laboratory values, fluid and blood product use, and outcomes were examined. Nineteen patients underwent liver transplantation prior to the implementation of TEG, and 19 had perioperative TEG. The most common indications for transplant were BA (n = 14), HB (n = 7), and metabolic disorders (n = 7). Intraoperative blood loss, urine output, fluid and blood product use were similar between groups. However, the use of fresh frozen plasma decreased significantly in TEG patients within the first 24 hours (29 vs 0 mL/kg, P < .01), and between 24 and 48 hours (12 vs 0 mL/kg, P = .01) post-operatively. The total use of fresh frozen plasma during hospitalization was markedly reduced (111 vs 17 mL/kg, P < .01). Four patients in the TEG group had thromboembolic graft complications, including portal vein or hepatic artery thrombosis, and underwent retransplantation. The decreased use of fresh frozen plasma since implementation of TEG is an important finding for resource utilization and patient safety. However, the increased incidence of thromboembolic complications requires further investigation.

Intestinal transplantation in children with multiple intestinal atresias and immunodeficiency.

GVHD has been reported in 8-10% of children after small bowel transplant (SBTx). Immunodeficient children may be predisposed to aggressive, steroid-resistant GVHD. There exists a unique association of immunodeficiency in children with MIA (MIAI). We report on our SBTx experience in patients with the diagnosis of MIAI, their high incidence of GVHD, and the possible role of stem cell transplantation in these patients. We performed a review of records from children that underwent SBTx or that we evaluated for SBTx at our institution. We focused on the diagnoses of atresia, multiple intestinal atresia, immunodeficiency, and GVHD in our patient population. Children with MIAI are likely to experience severe GVHD following SBTx. MIAI correlated with a 100% incidence of GVHD in these patients. Of the five patients with MIAI that underwent SBTx, three succumbed to severe GVHD within 1-6 months after SBTx. One patient received stem cell transplant prior to SBTx and did not develop severe GVHD, but died from influenza nine months after SBTx. Our unique patient survives long-term, with engraftment of donor γ δ T cells. He has mild, persistent chronic GVHD. Atresia is a common referral diagnosis for SBTx. Patients with multiple atresias, especially MIAI, are at significant risk for the complication of GVHD following SBTx. We recommend careful immunologic assessment and antecedent stem cell transplant in children with MIAI prior to SBTx.

Hepatic fibrosis persists and progresses despite biochemical improvement in children treated with intravenous fish oil emulsion.

OBJECTIVES: Intestinal failure-associated liver disease (IFALD) is a multifactorial process, which can culminate in cirrhosis and need for transplantation. Fish oil-based lipid emulsions (FOE) reportedly reverse hyperbilirubinemia, but there are little data on their effect on the histopathology of IFALD. METHODS: We blindly examined sequential liver biopsy data on 6 children receiving FOE, with scoring of cholestasis, inflammation, fibrosis, and ductal proliferation based on standardized systems. This information was correlated with biochemical and clinical data to determine any possible relations between biologic and histologic improvement. RESULTS: The median gestational age was 35 weeks, median birth weight 2064 g, and common most reason for intestinal loss was gastroschisis (5/6 children). Median intestinal length was 26 cm beyond the ligament of Treitz and most children had roughly 2 of 3 of their colonic length. It was observed that although hyperbilirubinemia reversed and hepatic synthetic function was preserved across timepoints, fibrosis was persistent in 2 cases, progressive in 3 cases, and regressed in only 1. It remained severe (grade 2 or higher) in 5 of 6 children at last biopsy. Histologic findings of cholestasis improved in all patients and inflammation improved in 5 of 6 children. There were mixed effects on ductal proliferation and steatosis. CONCLUSIONS: In children treated with FOE, reversal of hyperbilirubinemia is not reflected by a similar histologic regression of fibrosis at the timepoints studied. Children with IFALD should have active ongoing treatment and be considered for early referral to an Intestinal Failure Program even with a normalized bilirubin.

Rapamycin-conditioned, alloantigen-pulsed myeloid dendritic cells present donor MHC class I/peptide via the semi-direct pathway and inhibit survival of antigen-specific CD8(+) T cells in vitro and in vivo.

Dendritic cells (DC) are "professional" bone marrow-derived antigen (Ag)-presenting cells of interest both as therapeutic targets and potential cellular vaccines due to their ability to regulate innate and adaptive immunity. Harnessing the inherent tolerogenicity of DC is a promising and incompletely explored approach to the prevention of allograft rejection. Previously, we and others have reported the ability of pharmacologically-modified DC, that resist maturation, to inhibit CD4(+) T cell responses and prolong allograft survival. Here we evaluated the ability of murine myeloid DC conditioned with the immunosuppressive pro-drug rapamycin (RAPA) to acquire and directly present alloAg to syngeneic CD8(+) T cells. RAPA-conditioned DC (RAPA-DC) pulsed with allogeneic splenocyte lysate acquired and expressed donor MHC class I and enhanced the apoptotic death of directly-reactive donor Ag-specific CD8(+) T cells in vitro. Moreover, following their adoptive transfer, they reduced the survival of these T cells in vivo. The ability of RAPA-DC to inhibit the survival of alloAg-specific CD8(+) T cells provides a potential mechanism by which host-derived DC may act as negative regulators of T cell alloreactivity and support donor-specific unresponsiveness. Adoptive cell therapy with alloAg-pulsed RAPA-DC may offer an effective approach to suppression of alloimmunity, with reduced dependence on systemic immunosuppression.

Pharmacological modification of dendritic cells to promote their tolerogenicity in transplantation.

Dendritic cells (DCs) are uniquely specialized antigen-presenting cells (APC) that play critical roles in both the stimulation and regulation of immune responses, including T-cell responses to transplanted organs. The inherent tolerogenicity of non-activated or "immature" DCs is well documented. Importantly, the infusion of DCs that are made resistant to activating inflammatory stimuli by "conditioning" through exposure to clinically approved immunosuppressants, such as corticosteroids, deoxyspergualin, and recently, rapamycin (RAPA), has produced encouraging outcomes in experimental models. Indeed, the infusion of RAPA-conditioned, host-derived DCs, pulsed with alloantigen, prolongs allograft survival. In particular, when the RAPA-conditioned DCs are delivered repeatedly or in combination with a short course of immunosuppression indefinite allograft survival is observed, typically associated with increased Foxp3(+) T-regulatory cells (Treg). Herein, we detail the procedures to generate and characterize RAPA-conditioned murine DCs (RAPA-DCs) ex vivo and in vivo. RAPA-DCs represent a pharmacologically conditioned DC population that promotes allograft survival and enriches for antigen-specific T-regulatory cells (Treg). DCs conditioned with immunosuppressive agents, like RAPA, represent novel and clinically applicable vectors or "negative" cellular vaccines, which can be loaded with donor antigen, and potentially used to promote/maintain organ transplant tolerance.

Rapamycin-conditioned dendritic cells are poor stimulators of allogeneic CD4+ T cells, but enrich for antigen-specific Foxp3+ T regulatory cells and promote organ transplant tolerance.

The ability of dendritic cells (DC) to regulate Ag-specific immune responses via their influence on T regulatory cells (Treg) may be key to their potential as therapeutic tools or targets for the promotion/restoration of tolerance. In this report, we describe the ability of maturation-resistant, rapamycin (RAPA)-conditioned DC, which are markedly impaired in Foxp3(-) T cell allostimulatory capacity, to favor the stimulation of murine alloantigen-specific CD4(+)CD25(+)Foxp3(+) Treg. This was distinct from control DC, especially following CD40 ligation, which potently expanded non-Treg. RAPA-DC-stimulated Treg were superior alloantigen-specific suppressors of T effector responses compared with those stimulated by control DC. Supporting the ability of RAPA to target effector T and B cells, but permit the proliferation and suppressive function of Treg, an infusion of recipient-derived alloantigen-pulsed RAPA-DC followed by a short postoperative course of low-dose RAPA promoted indefinite (>100 day) heart graft survival. This was associated with graft infiltration by CD4(+)Foxp3(+) Treg and the absence of transplant vasculopathy. The adoptive transfer of CD4(+) T cells from animals with long-surviving grafts conferred resistance to rejection. These novel findings demonstrate that, whereas maturation resistance does not impair the capacity of RAPA-DC to modulate Treg, it profoundly impairs their ability to expand T effector cells. A demonstration of this mechanism endorses their potential as tolerance-promoting cellular vaccines.