Cell-based BSEP trans-inhibition: A novel, non-invasive test for diagnosis of antibody-induced BSEP deficiency.

Background & Aims: Antibody-induced bile salt export pump deficiency (AIBD) is an acquired form of intrahepatic cholestasis, which may develop following orthotopic liver transplantation (OLT) for progressive familial intrahepatic cholestasis type 2 (PFIC-2). Approximately 8-33% of patients with PFIC-2 who underwent a transplant develop bile salt export pump (BSEP) antibodies, which trans-inhibit this bile salt transporter from the extracellular, biliary side. AIBD is diagnosed by demonstration of BSEP-reactive and BSEP-inhibitory antibodies in patient serum. We developed a cell-based test directly measuring BSEP trans-inhibition by antibodies in serum samples to confirm AIBD diagnosis. Methods: Sera from healthy controls and cholestatic non-AIBD or AIBD cases were tested (1) for anticanalicular reactivity by immunofluorescence staining of human liver cryosections, (2) for anti-BSEP reactivity by immunofluorescence staining of human embryonic kidney 293 (HEK293) cells expressing BSEP-enhanced yellow fluorescent protein (EYFP) and immunodetection of BSEP-EYFP on Western blot, and (3) for BSEP trans-inhibition using HEK293 cells stably expressing Na+/taurocholate cotransporting polypeptide (NTCP)-mCherry and BSEP-EYFP. The trans-inhibition test uses [3H]-taurocholate as substrate and is divided into an uptake phase dominated by NTCP followed by BSEP-mediated export. For functional analysis, sera were bile salt depleted. Results: We found BSEP trans-inhibition by seven sera containing anti-BSEP antibodies, but not by five cholestatic or nine control sera, all lacking BSEP reactivity. Prospective screening of a patient with PFIC-2 post OLT showed seroconversion to AIBD, and the novel test method allowed monitoring of treatment response. Notably, we identified a patient with PFIC-2 post OLT with anti-BSEP antibodies yet without BSEP trans-inhibition activity, in line with asymptomatic presentation at serum sampling. Conclusions: Our cell-based assay is the first direct functional test for AIBD and allows confirmation of diagnosis as well as monitoring under therapy. We propose an updated workflow for AIBD diagnosis including this functional assay. Impact and Implications: Antibody-induced BSEP deficiency (AIBD) is a potentially serious complication that may affect patients with PFIC-2 after liver transplantation. To improve its early diagnosis and thus immediate treatment, we developed a novel functional assay to confirm AIBD diagnosis using a patient's serum and propose an updated diagnostic algorithm for AIBD.

Genotype-phenotype relationships of truncating mutations, p.E297G and p.D482G in bile salt export pump deficiency.

Background & Aims: Bile salt export pump (BSEP) deficiency frequently necessitates liver transplantation in childhood. In contrast to two predicted protein truncating mutations (PPTMs), homozygous p.D482G or p.E297G mutations are associated with relatively mild phenotypes, responsive to surgical interruption of the enterohepatic circulation (siEHC). The phenotype of patients with a compound heterozygous genotype of one p.D482G or p.E297G mutation and one PPTM has remained unclear. We aimed to assess their genotype-phenotype relationship. Methods: From the NAPPED database, we selected patients with homozygous p.D482G or p.E297G mutations (BSEP1/1; n = 31), with one p.D482G or p.E297G, and one PPTM (BSEP1/3; n = 30), and with two PPTMs (BSEP3/3; n = 77). We compared clinical presentation, native liver survival (NLS), and the effect of siEHC on NLS. Results: The groups had a similar median age at presentation (0.7-1.3 years). Overall NLS at age 10 years was 21% in BSEP1/3 vs. 75% in BSEP1/1 and 23% in BSEP3/3 (p <0.001). Without siEHC, NLS in the BSEP1/3 group was similar to that in BSEP3/3, but considerably lower than in BSEP1/1 (at age 10 years: 38%, 30%, and 71%, respectively; p = 0.003). After siEHC, BSEP1/3 and BSEP3/3 were associated with similarly low NLS, while NLS was much higher in BSEP1/1 (10 years after siEHC, 27%, 14%, and 92%, respectively; p <0.001). Conclusions: Individuals with BSEP deficiency with one p.E297G or p.D482G mutation and one PPTM have a similarly severe disease course and low responsiveness to siEHC as those with two PPTMs. This identifies a considerable subgroup of patients who are unlikely to benefit from interruption of the enterohepatic circulation by either surgical or ileal bile acid transporter inhibitor treatment. Impact and implications: This manuscript defines the clinical features and prognosis of individuals with BSEP deficiency involving the combination of one relatively mild and one very severe BSEP deficiency mutation. Until now, it had always been assumed that the mild mutation would be enough to ensure a relatively good prognosis. However, our manuscript shows that the prognosis of these patients is just as poor as that of patients with two severe mutations. They do not respond to biliary diversion surgery and will likely not respond to the new IBAT (ileal bile acid transporter) inhibitors, which have recently been approved for use in BSEP deficiency.

ABO-incompatible Pediatric Liver Transplantation With Antibody and B-cell Depletion-free Immunosuppressive Protocol in High Consanguinity Communities.

The success of orthotopic liver transplantation as a life-saving treatment has led to new indications and a greater competition for organ grafts. Pediatric patients with acute liver-related crises can benefit from orthotopic liver transplantation, but organ availability in the limited time can be a major obstacle. Crossing ABO blood group barriers could increase the organs available to such patients. Methods: From November 2010 to June 2015, 176 children aged 0.2-to18 y were transplanted in the King Faisal Specialist Hospital and Research Center. Out of those, 19 children were transplanted across blood group barriers (ABO incompatible). The underlying diseases were biliary atresia (n = 6); progressive familial intrahepatic cholestasis type 2 (n = 4); Crigler-Najjar syndrome (n = 3); hepatoblastoma (n = 2); and urea cycle disorder, Caroli disease, cryptogenic cirrhosis, and neonatal sclerosing cholangitis (n = 1 each). Immunosuppression consisted of basiliximab, mycophenolate, tacrolimus, and steroids. Pretransplant prophylactic plasmapheresis, high-dose immunoglobulins, and rituximab were not administered. Results: The grafts were from living donors (n = 17) and deceased donors (n = 2). Living donor morbidity was nil. The recipient median age was 21 mo (5-70 mo). After a median follow-up of 44 mo, 2 recipients (10%) died because of sepsis, 1 because of uncontrolled acute myeloid leukemia. The overall rejection rate was 7%, and no grafts were lost because of antibody-mediated rejection (AMR). HLA matching was 3.8 of 6 (A, B, DR), and there were 2 patients presented with acute cellular rejection, 1 patient with AMR, and 1 patient with biliary strictures. Conclusions: ABO incompatible liver transplantation is a feasible and life-saving option even with antibody and B-cell depletion-free protocol without increasing the risks for AMR. We speculate that this excellent result is most likely because of presence of relatively low titer ABO isoagglutinins and the high HLA match compatibility caused by habit of longstanding interfamilial marriages as typical of Saudi Arabia.

Impact of Genotype, Serum Bile Acids, and Surgical Biliary Diversion on Native Liver Survival in FIC1 Deficiency.

BACKGROUND AND AIMS: Mutations in ATPase phospholipid transporting 8B1 (ATP8B1) can lead to familial intrahepatic cholestasis type 1 (FIC1) deficiency, or progressive familial intrahepatic cholestasis type 1. The rarity of FIC1 deficiency has largely prevented a detailed analysis of its natural history, effects of predicted protein truncating mutations (PPTMs), and possible associations of serum bile acid (sBA) concentrations and surgical biliary diversion (SBD) with long-term outcome. We aimed to provide insights by using the largest genetically defined cohort of patients with FIC1 deficiency to date. APPROACH AND RESULTS: This multicenter, combined retrospective and prospective study included 130 patients with compound heterozygous or homozygous predicted pathogenic ATP8B1 variants. Patients were categorized according to the number of PPTMs (i.e., splice site, frameshift due to deletion or insertion, nonsense, duplication), FIC1-A (n = 67; no PPTMs), FIC1-B (n = 29; one PPTM), or FIC1-C (n = 34; two PPTMs). Survival analysis showed an overall native liver survival (NLS) of 44% at age 18 years. NLS was comparable among FIC1-A, FIC1-B, and FIC1-C (% NLS at age 10 years: 67%, 41%, and 59%, respectively; P = 0.12), despite FIC1-C undergoing SBD less often (% SBD at age 10 years: 65%, 57%, and 45%, respectively; P = 0.03). sBAs at presentation were negatively associated with NLS (NLS at age 10 years, sBAs < 194 µmol/L: 49% vs. sBAs ≥ 194 µmol/L: 15%; P = 0.03). SBD decreased sBAs (230 [125-282] to 74 [11-177] µmol/L; P = 0.005). SBD (HR 0.55, 95% CI 0.28-1.03, P = 0.06) and post-SBD sBA concentrations < 65 µmol/L (P = 0.05) tended to be associated with improved NLS. CONCLUSIONS: Less than half of patients with FIC1 deficiency reach adulthood with native liver. The number of PPTMs did not associate with the natural history or prognosis of FIC1 deficiency. sBA concentrations at initial presentation and after SBD provide limited prognostic information on long-term NLS.

Genotype correlates with the natural history of severe bile salt export pump deficiency.

BACKGROUND & AIMS: Mutations in ABCB11 can cause deficiency of the bile salt export pump (BSEP), leading to cholestasis and end-stage liver disease. Owing to the rarity of the disease, the associations between genotype and natural history, or outcomes following surgical biliary diversion (SBD), remain elusive. We aimed to determine these associations by assembling the largest genetically defined cohort of patients with severe BSEP deficiency to date. METHODS: This multicentre, retrospective cohort study included 264 patients with homozygous or compound heterozygous pathological ABCB11 mutations. Patients were categorized according to genotypic severity (BSEP1, BSEP2, BSEP3). The predicted residual BSEP transport function decreased with each category. RESULTS: Genotype severity was strongly associated with native liver survival (NLS, BSEP1 median 20.4 years; BSEP2, 7.0 years; BSEP3, 3.5 years; p <0.001). At 15 years of age, the proportion of patients with hepatocellular carcinoma was 4% in BSEP1, 7% in BSEP2 and 34% in BSEP3 (p = 0.001). SBD was associated with significantly increased NLS (hazard ratio 0.50; 95% CI 0.27-0.94: p = 0.03) in BSEP1 and BSEP2. A serum bile acid concentration below 102 µmol/L or a decrease of at least 75%, each shortly after SBD, reliably predicted NLS of ≥15 years following SBD (each p <0.001). CONCLUSIONS: The genotype of severe BSEP deficiency strongly predicts long-term NLS, the risk of developing hepatocellular carcinoma, and the chance that SBD will increase NLS. Serum bile acid parameters shortly after SBD can predict long-term NLS. LAY SUMMARY: This study presents data from the largest genetically defined cohort of patients with severe bile salt export pump deficiency to date. The genotype of patients with severe bile salt export pump deficiency is associated with clinical outcomes and the success of therapeutic interventions. Therefore, genotypic data should be used to guide personalized clinical care throughout childhood and adulthood in patients with this disease.

Early Hepatocellular Carcinoma Associated With Fibrocystic Liver Disease in a 10-Year-Old Child: A Case Report.

BACKGROUND: Fibrocystic liver-kidney disease is caused by a group of rare and genetically diverse disorders that are associated with kidney cysts or dysplasia and ductal plate malformation in the liver. There have been several reports of liver neoplasias arising in hepatobiliary fibrocystic diseases. However, most were cholangiocarcinoma; cases involving hepatocellular carcinoma (HCC) are rare, and all the reported cases are related with adults. CASE REPORT: A 10-year-old girl with a history of repeated gastrointestinal bleeding underwent banding and sclerotherapy multiple times and had a history of a Portosystemic shunt without any significant benefit. She was referred to us as a case of fibrocystic liver disease with decompensated liver disease for liver transplantation. The patient underwent living donor liver transplantation, and the explanted liver histopathology report is documented. The explant liver weighed 838 g and measured 21 × 13 × 8.5 cm with the attached gallbladder measuring 7 × 3 × 0.2 cm (in wall thickness). The external surface was covered with multiple white nodules ranging in size from 0.4 to 1 cm. Serial slicing revealed an ill-defined, yellow, soft lesion (4 × 2.5 × 2.5 cm) localized in the subcapsular area of the left lobe (segment 4). The rest of the cut surface was green and nodular (cirrhotic). Microscopy from largest nodule was consistent with early hepatocellular carcinoma.The rest of the liver was cirrhotic, and the morphology was consistent with fibrocystic disease of liver. CONCLUSION: We report a rare case of HCC associated with fibrocystic liver disease. When diagnosing fibrocystic liver disease without known risk factors, the presence of HCC must be considered, and vice versa. To our knowledge, this is the first reported case of HCC associated with fibrocystic liver disease in a 10-year-old child.

First fully laparoscopic donor hepatectomy for pediatric liver transplantation using the indocyanine green near-infrared fluorescence imaging in the Middle East: a case report.

Living donor liver transplantation (LDLT) is a well-established treatment modality for several pediatric end-stage liver diseases owning excellent long-term results. Left lateral sectionectomy (LLS) through an open approach is a well-standardized procedure. This technique has been modified for a fully laparoscopic approach and gaining more and more interest worldwide. We report herein the first fully laparoscopic LLS for pediatric LDLT in the Middle East with the use of indocyanine green dye and near-infrared fluorescence imaging to identify the biliary ducts intraoperatively. The recipient was a 2-year-old girl affected by glycogen storage disease type IV. The mother, aged 21 years, was her donor. The surgical technique, key-points of this procedure, and outcome are hereby discussed.

Role of wireless capsule endoscopy in reclassifying inflammatory bowel disease in children.

OBJECTIVE: To evaluate the role of wireless capsule endoscopy in identifying small bowel lesions in pediatric patients with newly diagnosed colonic inflammatory bowel disease (IBD) type unclassified (IBDU), and to assess whether capsule endoscopy findings result in altered patient management. METHODS: Ten pediatric patients recently diagnosed with IBDU through standard investigations were recruited from the pediatric gastroenterology clinic at McMaster Children's Hospital to undergo capsule endoscopy using the Pillcam SB(TM) (Given Imaging) capsule. Findings consistent with a diagnosis of Crohn's disease required the identification of at least three ulcerations. RESULTS: Three out of ten patients had newly identified findings on capsule endoscopy that met criteria for Crohn's disease. Three more patients had findings suspicious for Crohn's disease, but failed to meet the diagnostic criteria. Three additional patients had findings most consistent with ulcerative colitis, and one had possible gastritis with a normal intestine. Findings from capsule endoscopy allowed for changes in the medical management of three patients. In all ten cases, capsule endoscopy allowed for a better characterization of the type and extent of disease. No adverse outcomes occurred in the present cohort. CONCLUSION: This prospective study reveals that wireless capsule endoscopy is feasible, valuable, and non-invasive, offering the ability to potentially better characterize newly diagnosed pediatric IBDU cases by identifying lesions in the small bowel and reclassifying these as Crohn's disease.

Papel da cápsula endoscópica na reclassificação da doença inflamatória intestinal em crianças / Role of wireless capsule endoscopy in reclassifying inflammatory bowel disease in children

OBJECTIVE: To evaluate the role of wireless capsule endoscopy in identifying small bowel lesions in pediatric patients with newly diagnosed colonic inflammatory bowel disease (IBD) type unclassified (IBDU), and to assess whether capsule endoscopy findings result in altered patient management. METHODS: Ten pediatric patients recently diagnosed with IBDU through standard investigations were recruited from the pediatric gastroenterology clinic at McMaster Children's Hospital to undergo capsule endoscopy using the Pillcam SB TM (Given Imaging) capsule. Findings consistent with a diagnosis of Crohn's disease required the identification of at least three ulcerations. RESULTS: Three out of ten patients had newly identified findings on capsule endoscopy that met criteria for Crohn's disease. Three more patients had findings suspicious for Crohn's disease, but failed to meet the diagnostic criteria. Three additional patients had findings most consistent with ulcerative colitis, and one had possible gastritis with a normal intestine. Findings from capsule endoscopy allowed for changes in the medical management of three patients. In all ten cases, capsule endoscopy allowed for a better characterization of the type and extent of disease. No adverse outcomes occurred in the present cohort. CONCLUSIONS: This prospective study reveals that wireless capsule endoscopy is feasible, valuable, and non-invasive, offering the ability to potentially better characterize newly diagnosed pediatric IBDU cases by identifying lesions in the small bowel and reclassifying these as Crohn's disease. Further investigation is warranted.

OBJETIVO: Avaliar o papel da cápsula endoscópica na identificação de lesões no intestino delgado em pacientes pediátricos com DII inespecífica (DIII) diagnosticada recentemente e avaliar se os achados da cápsula endoscópica resultam em alterações no tratamento dos pacientes. MÉTODOS: Dez pacientes pediátricos recém-diagnosticados com DIII por meio de investigações padrão foram recrutados da clínica de gastroenterologia pediátrica no McMaster Children's Hospital, para serem submetidos a exame com a cápsula endoscópica Pillcam SB TM (Given Imaging). Achados compatíveis com o diagnóstico da doença de Crohn exigiram a identificação de pelo menos três ulcerações. RESULTADOS: De 10 pacientes, três apresentaram achados novos com a cápsula endoscópica que satisfizeram o critério para a doença de Crohn. Outros três apresentaram achados com suspeita de doença de Crohn, porém não atenderam nossos critérios de diagnóstico. Apresentaram achados mais compatíveis com colite ulcerativa outros três pacientes, e um apresentava possível gastrite com intestino normal. Os achados da cápsula endoscópica possibilitaram mudanças no tratamento médico de três pacientes. Em todos os dez casos, a cápsula endoscópica permitiu uma melhor caracterização do tipo e da extensão da doença. Não houve resultado adverso em nossa coorte. CONCLUSÃO: Este estudo prospectivo revela que a cápsula endoscópica é viável, útil e não invasiva, que oferece a possibilidade de melhor caracterização de casos de DIII pediátricos recém-diagnosticados ao identificar lesões no intestino delgado e reclassificá-las como doença de Crohn.

Progress and outcomes of the first high-volume pediatric liver transplantation program in Saudi Arabia.

In 2010, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia, established a dedicated Organ Transplant Center to overcome the inadequacy in transplantation care in the region. Due to the high need for solid organ transplantation in children, this center focused on pediatric transplantation. Between 2011 and 2013, a total of 112 pediatric liver transplantations have been performed in our center, mostly from living donors (n=103, 92%). Eight percent of transplants were performed from deceased donors (n=9). Of the 112 transplants, 38.4% of children were below one year of age. There was a predominance of genetic-metabolic disorders (48.2%) as indications for transplant. Extra-hepatic biliary atresia was the indication in only 29.5% of transplant cases. End-stage liver disease of unknown origin accounted for 7.1% of cases. The actuarial recipient and graft survival are 93% and 89%, respectively. In-hospital morbidities amounted to 17% for surgical complications (n=19) and 18% for medical complications (n=20). Seven percent of recipients developed biopsy proven rejection during hospital stay. Five patients died late after discharge suddenly at home or at peripheral hospitals for unknown reasons. Overall, this newly established pediatric liver transplantation program could develop into a high-volume pediatric liver transplantation center in a short period of time due to the high need for liver transplantation in the country. In contrast to the experience in western or eastern countries, there is a high rate of indications for metabolic/genetic disorders. The early results of patient and graft survival are convincing. The long-term outcomes were compromised by an insufficient general healthcare system and cultural barriers.