Progressive familial intrahepatic cholestasis type 1 and extrahepatic features: no catch-up of stature growth, exacerbation of diarrhea, and appearance of liver steatosis after liver transplantation

The Phospholipid Flippase ATP8B1 is Involved in the Pathogenesis of Ulcerative Colitis via Establishment of Intestinal Barrier Function

AIMS

Patients with mutations in ATP8B1 develop progressive familial intrahepatic cholestasis type 1 [PFIC1], a severe liver disease that requires life-saving liver transplantation. PFIC1 patients also present with gastrointestinal problems, including intestinal inflammation and diarrhoea, which are aggravated after liver transplantation. Here we investigate the intestinal function of ATP8B1 in relation to inflammatory bowel diseases.

METHODS

ATP8B1 expression was investigated in intestinal samples of patients with Crohn's disease [CD] or ulcerative colitis [UC] as well as in murine models of intestinal inflammation. Colitis was induced in ATP8B1-deficient mice with dextran sodium sulphate [DSS] and intestinal permeability was investigated. Epithelial barrier function was assessed in ATP8B1 knockdown Caco2-BBE cells. Co-immunoprecipitation experiments were performed in Caco2-BBE cells overexpressing ATP8B1-eGFP. Expression and localization of ATP8B1 and tight junction proteins were investigated in cells and in biopsies of UC and PFIC1 patients.

RESULTS

ATP8B1 expression was decreased in UC and DSS-treated mice, and was associated with a decreased tight junctional pathway transcriptional programme. ATP8B1-deficient mice were extremely sensitive to DSS-induced colitis, as evidenced by increased intestinal barrier leakage. ATP8B1 knockdown cells showed delayed barrier establishment that affected Claudin-4 [CLDN4] levels and localization. CLDN4 immunohistochemistry showed a tight junctional staining in control tissue, whereas in UC and intestinal PFIC1 samples, CLDN4 was not properly localized.

CONCLUSION

ATP8B1 is important in the establishment of the intestinal barrier. Downregulation of ATP8B1 levels in UC, and subsequent altered localization of tight junctional proteins, including CLDN4, might therefore be an important mechanism in UC pathophysiology.

Exceptional Liver Transplant Indications: Unveiling the Uncommon Landscape

Liver transplantation represents the definitive intervention for various etiologies of liver failure and encompasses a spectrum of rare indications crucial to understanding the diverse landscape of end-stage liver disease, with significantly improved survival rates over the past three decades. Apart from commonly encountered liver transplant indications such as decompensated cirrhosis and liver cancer, several rare diseases can lead to transplantation. Recognition of these rare indications is essential, providing a lifeline to individuals facing complex liver disorders where conventional treatments fail. Collaborative efforts among healthcare experts lead not only to timely interventions but also to the continuous refinement of transplant protocols. This continued evolution in transplant medicine promises hope for those facing diverse and rare liver diseases, marking a paradigm shift in the landscape of liver disease management.

Outcomes of pediatric liver transplantation for progressive familial intrahepatic cholestasis

BACKGROUND

Progressive familial intrahepatic cholestasis (PFIC) is a heterogenous group of inherited hepatocellular disorders and the clinical aspects, role of liver transplantation (LT), and its outcomes remain largely unelucidated. We present our data of LT for each type of PFIC and compare their early, and long-term outcomes, highlighting their individual differences and management strategies.

METHODS

Prospectively collected data over a decade (2011-2022) of children with PFIC who underwent LT was analyzed. The groups (PFIC 1-4) were compared with regard to early and long-term outcomes including attainment of catch-up growth.

RESULTS

Of 60 children with PFIC who underwent LT, 13, 11, 31 & 5 were of PFIC 1, 2, 3 & 4, respectively. There were no significant differences in gender, PELD scores, BMI, type of grafts, cold and warm ischemia times, intraoperative blood loss, and morbidity among the groups. Post-LT chronic diarrhea was observed in 6 (46.1%) children with PFIC-I, and of them, 3 (23%) developed graft steatohepatitis. Three of these children underwent total internal biliary diversion (TIBD) and on 1-year follow-up, their graft steatosis resolved and they attained catch-up growth. Catch-up growth was significantly poorer in the PFIC1 group (44.4% vs. 88%, 90%, 100% p < .001). Overall 1- and 5-year patient survival of the four PFIC groups (1-4) were 69.2%, 81.8%, 96.8%, 100% & 69.2%, 81.8%, 96.8%, 100%, respectively.

CONCLUSION

Ours is the largest to-date series of LT for PFIC illustrating their short- and long-term outcomes. While the results for the whole cohort were excellent, those after LT for PFIC1 was relatively poorer as reflected by catch-up growth, graft steatosis, and post-LT diarrhea, which can be optimized by the addition of TIBD during LT.

Diagnosis and management of Alagille and progressive familial intrahepatic cholestasis

Alagille syndrome and progressive familial intrahepatic cholestasis are conditions that can affect multiple organs. Advancements in molecular testing have aided in the diagnosis of both. The impairment of normal bile flow and secretion leads to the various hepatic manifestations of these diseases. Medical management of Alagille syndrome and progressive familial intrahepatic cholestasis remains mostly targeted on supportive care focusing on quality of life, cholestasis, and fat-soluble vitamin deficiency. The most difficult therapeutic issue is typically related to pruritus, which can be managed by various medications such as ursodeoxycholic acid, rifampin, cholestyramine, and antihistamines. Surgical operations were previously used to disrupt enterohepatic recirculation, but recent medical advancements in the use of ileal bile acid transport inhibitors have shown great efficacy for the treatment of pruritus in both Alagille syndrome and progressive familial intrahepatic cholestasis.

Intestinal Atp8b1 dysfunction causes hepatic choline deficiency and steatohepatitis

Choline is an essential nutrient, and its deficiency causes steatohepatitis. Dietary phosphatidylcholine (PC) is digested into lysoPC (LPC), glycerophosphocholine, and choline in the intestinal lumen and is the primary source of systemic choline. However, the major PC metabolites absorbed in the intestinal tract remain unidentified. ATP8B1 is a P4-ATPase phospholipid flippase expressed in the apical membrane of the epithelium. Here, we use intestinal epithelial cell (IEC)-specific Atp8b1-knockout (Atp8b1IEC-KO) mice. These mice progress to steatohepatitis by 4 weeks. Metabolomic analysis and cell-based assays show that loss of Atp8b1 in IEC causes LPC malabsorption and thereby hepatic choline deficiency. Feeding choline-supplemented diets to lactating mice achieves complete recovery from steatohepatitis in Atp8b1IEC-KO mice. Analysis of samples from pediatric patients with ATP8B1 deficiency suggests its translational potential. This study indicates that Atp8b1 regulates hepatic choline levels through intestinal LPC absorption, encouraging the evaluation of choline supplementation therapy for steatohepatitis caused by ATP8B1 dysfunction.

Management and outcomes after liver transplantation for progressive familial intrahepatic cholestasis: A systematic review and meta-analysis

BACKGROUND

Progressive familial intrahepatic cholestasis (PFIC) is a heterogeneous rare congenital cholestatic liver disease. Disease progression might necessitate liver transplantation (LT). The aim of this study was to describe the outcome of PFIC1-4 patients after LT.

METHODS

Electronic databases were searched to identify studies on PFIC and LT. Patients were categorized according to PFIC type, genotype, graft type, age at LT, time of follow-up, and complications and treatment during follow-up.

RESULTS

Seventy-nine studies with 507 patients met inclusion criteria; most patients were classified as PFIC1-3. The median age at LT was 50 months. The overall 5-year patient survival was 98.5%. PFIC1 patients with diarrhea after LT were at significant risk of developing graft steatosis ( p < 0.0001). Meta-analysis showed an efficacy of 100% [95% CI: 73.9%-100%] for surgical biliary diversion to ameliorate steatosis and 94.9% [95% CI: 53.7%-100%] to improve diarrhea (n = 8). PFIC2 patients with bile salt export pump (BSEP)2 or BSEP3-genotype were at significant risk of developing antibody-induced BSEP deficiency (AIBD) ( p < 0.0001), which was reported in 16.2% of patients at a median of 36.5 months after LT. Meta-analysis showed an efficacy of 81.1% [95% CI: 47.5%-100%] for rituximab-based treatment regimens to improve AIBD (n = 18). HCC was detected in 3.6% of PFIC2 and 13.8% of PFIC4 patients at LT.

CONCLUSIONS

Fifty percent of PFIC1 patients develop diarrhea and steatosis after LT. Biliary diversion can protect the graft from injury. PFIC2 patients with BSEP2 and BSEP3 genotypes are at significant risk of developing AIBD, and rituximab-based treatment regimens effectively improve AIBD. PFIC3 patients have no PFIC-specific complications following LT.

Internal Ileal Diversion as Treatment for Progressive Familial Intrahepatic Cholestasis Type 1-Associated Graft Inflammation and Steatosis after Liver Transplantation

BACKGROUND

Progressive Familial Intrahepatic cholestasis type I (PFIC1) is a rare congenital hepatopathy causing cholestasis with progressive liver disease. Surgical interruption of the enterohepatic circulation, e.g., surgical biliary diversion (SBD) can slow down development of liver cirrhosis. Eventually, end stage liver disease necessitates liver transplantation (LT). PFIC1 patients might develop diarrhea, graft steatosis and inflammation after LT. SBD after LT was shown to be effective in the alleviation of liver steatosis and graft injury.

CASE REPORT

Three PFIC1 patients received LT at the ages of two, two and a half and five years. Shortly after LT diarrhea and graft steatosis was recognized, SBD to the terminal ileum was opted to prevent risk for ascending cholangitis. After SBD, inflammation and steatosis was found to be reduced to resolved, as seen by liver biochemistry and ultrasounds. Diarrhea was reported unchanged.

CONCLUSION

We present three PFIC1 cases for whom SBD to the terminal ileum successfully helped to resolve graft inflammation and steatosis.

Cholestatic liver diseases of genetic etiology: Advances and controversies

With the application of modern investigative technologies, cholestatic liver diseases of genetic etiology are increasingly identified as the root cause of previously designated "idiopathic" adult and pediatric liver diseases. Here, we review advances in the field enhanced by a deeper understanding of the phenotypes associated with specific gene defects that lead to cholestatic liver diseases. There are evolving areas for clinicians in the current era specifically regarding the role for biopsy and opportunities for a "sequencing first" approach. Risk stratification based on the severity of the genetic defect holds promise to guide the decision to pursue primary liver transplantation versus medical therapy or nontransplant surgery, as well as early screening for HCC. In the present era, the expanding toolbox of recently approved therapies for hepatologists has real potential to help many of our patients with genetic causes of cholestasis. In addition, there are promising agents under study in the pipeline. Relevant to the current era, there are still gaps in knowledge of causation and pathogenesis and lack of fully accepted biomarkers of disease progression and pruritus. We discuss strategies to overcome the challenges of genotype-phenotype correlation and draw attention to the extrahepatic manifestations of these diseases. Finally, with attention to identifying causes and treatments of genetic cholestatic disorders, we anticipate a vibrant future of this dynamic field which builds upon current and future therapies, real-world evaluations of individual and combined therapeutics, and the potential incorporation of effective gene editing and gene additive technologies.

Long-Term Outcomes of Patients With Progressive Familial Intrahepatic Cholestasis After Biliary Diversion

OBJECTIVES

Progressive familial intrahepatic cholestasis is a heterogeneous group of genetic disorders characterized by disrupted bile homeostasis. Patients with this disease typically present with cholestasis and pruritus early in life and often progress to end-stage liver disease. The clinical symptoms that patients with progressive familial intrahepatic cholestasis encounter are usually refractory to medical treatment. Although the effects of biliary diversion surgery on native liver survival are not exactly known, this procedure may provide a positive impact on pruritus and laboratory parameters in these patients.

MATERIALS AND METHODS

We retrospectively evaluated the clinical and laboratory characteristics of patients with progressive familial intrahepatic cholestasis who underwent partial external biliary diversion between 2002 and 2020 at our center. Diagnosis of progressive familial intrahepatic cholestasis was made by clinical, biochemical, and histopathological characteristics as well as genetic testing.

RESULTS

Nine patients were included in the study. Five patients required liver transplant during follow-up, with 4 having liver transplant as a result of endstage liver disease (median interval of 5 years). In 1 patient, partial external biliary diversion was performed 1.5 years after liver transplant for severe diarrhea, metabolic acidosis, and hepatic steatosis. Four patients did not require liver transplant during follow-up (median follow-up time of 7.6 years). Pruritus responded well to partial external biliary diversion in all patients. Among laboratory values evaluated 6 months after biliary diversion, only albumin showed significant improvement.

CONCLUSIONS

Partial external biliary diversion had favorable results on long-term follow-up. This procedure can provide the relief of pruritus and delay the requirement for liver transplant in patients with progressive familial intrahepatic cholestasis. In our view, partial external biliary diversion should be considered the first-line surgical management for patients with this disease.

Extrahepatic manifestations of progressive familial intrahepatic cholestasis syndromes: Presentation of a case series and literature review

BACKGROUND AND AIMS

Progressive familial intrahepatic cholestasis (PFIC) is a collective term for a heterogenous group of rare, inherited cholestasis syndromes. The number of genes underlying the clinical PFIC phenotype is still increasing. While progressive liver disease and its sequelae such as portal hypertension, pruritus and hepatocellular carcinoma determine transplant-free survival, extrahepatic manifestations may cause relevant morbidity.

METHODS

We performed a literature search for extrahepatic manifestations of PFIC associated with pathogenic gene variants in ATP8B1, ABCB11, ABCB4, TJP2, NR1H4 and MYO5B. To illustrate the extrahepatic symptoms described in the literature, PFIC cases from our centres were revisited.

RESULTS

Extrahepatic symptoms are common in PFIC subtypes, where the affected gene is expressed at high levels in other tissues. While most liver-associated complications resolve after successful orthotopic liver transplantation (OLT), some extrahepatic symptoms show no response or even worsen after OLT.

CONCLUSION

The spectrum of extrahepatic manifestations in PFIC highlights essential, non-redundant roles of the affected genes in other organs. Extrahepatic features contribute towards low health-related quality of life (HRQOL) and morbidity in PFIC. While OLT is often the only remaining, curative treatment, potential extrahepatic manifestations need to be carefully monitored and addressed.

Clinical outcomes of surgical management for rare types of progressive familial intrahepatic cholestasis: a case series

Background

Progressive familial intrahepatic cholestasis (PFIC) is a heterogeneous group of genetic autosomal recessive diseases that cause severe cholestasis, which progresses to cirrhosis and liver failure, in infancy or early childhood. We herein report the clinical outcomes of surgical management in patients with four types of PFIC.

Case presentation

Six patients diagnosed with PFIC who underwent surgical treatment between 1998 and 2020 at our institution were retrospectively assessed. Living-donor liver transplantation (LDLT) was performed in 5 patients with PFIC. The median age at LDLT was 4.8 (range: 1.9–11.4) years. One patient each with familial intrahepatic cholestasis 1 (FIC1) deficiency and bile salt export pump (BSEP) deficiency died after LDLT, and the four remaining patients, one each with deficiency of FIC1, BSEP, multidrug resistance protein 3 (MDR3), and tight junction protein 2 (TJP2), survived. One FIC1 deficiency recipient underwent LDLT secondary to deterioration of liver function, following infectious enteritis. Although he underwent LDLT accompanied by total external biliary diversion, the patient died because of PFIC-related complications. The other patient with FIC1 deficiency had intractable pruritus and underwent partial internal biliary diversion (PIBD) at 9.8 years of age, pruritus largely resolved after PIBD. One BSEP deficiency recipient, who had severe graft damage, experienced recurrence of cholestasis due to the development of antibodies against BSEP after LDLT, and eventually died due to graft failure. The other patient with BSEP deficiency recovered well after LDLT and there was no evidence of posttransplant recurrence of cholestasis. In contrast, recipients with MDR3 or TJP2 deficiency showed good courses and outcomes after LDLT.

Conclusions

Although LDLT was considered an effective treatment for PFIC, the clinical courses and outcomes after LDLT were still inadequate in patients with FIC1 and BSEP deficiency. LDLT accompanied by total biliary diversion may not be as effective for patients with FIC1 deficiency.

Pharmacokinetics and food impact assessment of ademetionine enteric-coated tablet as an endogenous substance drug in healthy Chinese volunteers

WHAT IS KNOWN AND OBJECTIVES

Ademetionine 1,4-Butanedisulfonate (SAMe) enteric-coated tablets are widely used for treatment of pre-cirrhotic and cirrhotic intrahepatic cholestasis, as well as intrahepatic cholestasis of pregnancy (ICP), but incomplete clinical data and interference from endogenous substances pose numerous challenges for clinical trial of ademetionine. The objective of this study was to evaluate the pharmacokinetic profile of SAMe enteric-coated tablets and to assess its food impact and safety in healthy Chinese subjects.

METHODS

A randomized, open-label, single-dose study was carried out to determine the pharmacokinetics of SAMe enteric-coated tablets administered in both fasted and postprandial conditions. Baseline collection and data adjustment were required to reduce the effect of endogenous substances. Relevant pharmacokinetic data from subjects administered the reference formulation will be disclosed and utilized in this thesis.

RESULTS

Twenty-four subjects with a body mass index (BMI) of 19-24 kg/m² were enrolled in the study and all completed the trial. The impact of food on the drug was noticeable, with faster absorption in the fasting group (T_max , 4.50 ± 1.07 and 7.50 ± 1.58 for the fasting and postprandial groups, respectively) but higher exposure in the postprandial group (AUC_0-inf , 4021.02 ± 3377.13 and 5087.28 ± 3539.26 for the fasting and postprandial groups, respectively). No serious adverse effects were observed in the fasted and postprandial conditions.

WHAT IS NEW AND CONCLUSIONS

The pharmacokinetic profile of SAMe enteric-coated tablets in healthy Chinese subjects was partially complemented in this study. SAMe enteric-coated tablets showed promising safety in fasted and postprandial conditions. However, the impact of food on the drug was significant and might access to the absorption site and affect biochemical reactions.

Progressive Familial Intrahepatic Cholestasis: Need for Genetic Analysis Before Liver Transplantation

The clinical course after liver transplantation (LT) in progressive familial intrahepatic cholestasis type 1 (PFIC1) is complicated by intractable diarrhoea, growth failure, graft steatosis and cirrhosis. Recent evidence from Japan suggests the role of genotype to predict outcome after LT. We report a case with pathogenic frameshift mutation who had failed partial external biliary diversion, underwent LT and his post-LT course has been complicated by intractable diarrhoea, growth failure, steatosis and fibrosis. This case highlights the fact that homozygous frameshift p.Gly197LeufsTer10 mutation in ATP8B1 is associated with poor outcome and genetic evaluation should be mandatory before subjecting the patient to LT.

Total Internal Biliary Diversion for Post-Liver Transplant PFIC-1-Related Allograft Injury

Steatohepatitis and diarrhea are well-known complications in children undergoing liver transplantation (LT) for progressive familial intrahepatic cholestasis (PFIC) type 1. Despite medical management with bile acid binders, the condition is progressive and can be associated with allograft loss. We report the case of a seven-year-old boy who underwent LT at the age of 2 years for PFIC type 1. Over the next five years, he developed refractory diarrhea, emaciation, worsening liver function, and steatohepatitis. Aiming to interrupt the enterohepatic circulation, at the age of 7 years, he underwent a total internal biliary diversion. The patient's postprocedure period was uneventful. His diarrhea settled and the transaminases normalized his follow-up liver biopsy after a year showed a complete resolution of steatohepatitis. At 18 months' follow-up, he has gained weight and remains asymptomatic. In this report, we show post-LT complications especially allograft injury related to the pathology of PFIC-1 can be safely and effectively managed by performing a total internal biliary diversion.

Liver Transplantation in Progressive Familial Intrahepatic Cholestasis with Normal Gamma-Glutamyl Transferase: Evaluation of Post-transplant Steatosis and Steatohepatitis

Background: Progressive familial intrahepatic cholestasis is a disease presenting with severe cholestasis and progressing to the end-stage liver disease later. Liver transplantation is a treatment modality available for progressive familial intrahepatic cholestasis, especially in patients with end-stage liver disease or those who are unsuitable for or have failed biliary diversion. Objectives: To evaluate clinical and pathological characteristics of progressive familial intrahepatic cholestasis patients who had undergone liver transplantation and to determine post-transplant steatosis and steatohepatitis. Methods: We evaluated 111 progressive familial intrahepatic cholestasis patients with normal gamma-glutamyl transferase that performed liver transplantation in Shiraz Transplant Center in Iran between March 2000 and March 2017. Results: The most common clinical manifestations were jaundice and pruritus. Growth retardation and diarrhea were detected in 76.6% and 42.5% of the patients. After transplantation, growth retardation was seen in 31.5% of the patients, and diarrhea in 36.9% of them. Besides, 29.1% of the patients died post-transplant. Post-transplant liver biopsies were taken from 50 patients, and 15 (30%) patients had steatosis or steatohepatitis, five of whom (10%) had macrovesicular steatosis alone, and 10 (20%) had steatohepatitis. Only one patient showed moderate bridging fibrosis (stage III), and none of them showed severe fibrosis. Conclusions: Liver transplantation is the final treatment option for these patients, and it can relieve most clinical manifestations. However, post-transplant mortality rate was relatively high in our center. Diarrhea, growth retardation, and steatosis are unique post-transplant complications in these patients. The rate of post-transplant steatosis and steatohepatitis in patients with liver biopsy in our study was 30%, with a significant difference from previous studies.

Long-Term Outcome after Liver Transplantation for Progressive Familial Intrahepatic Cholestasis

Background and Objectives: Progressive familial intrahepatic cholestasis (PFIC) is a rare autosomal recessive inherited disease divided into five types (PFIC 1-5). Characteristic for all types is early disease onset, which may result clinically in portal hypertension, fibrosis, cirrhosis, hepatocellular carcinoma (HCC), and extrahepatic manifestations. Liver transplantation (LT) is the only successful treatment approach. Our aim is to present the good long-term outcomes after liver transplantation for PFIC1, focusing on liver function as well as the occurrence of extrahepatic manifestation after liver transplantation. Materials and Methods: A total of seven pediatric patients with PFIC1 underwent liver transplantation between January 1999 and September 2019 at the Department of Surgery, Charité Campus Virchow Klinikum and Charité Campus Mitte of Charité-Universitätsmedizin Berlin. Long-term follow-up data were collected on all patients, specifically considering liver function and extrahepatic manifestations. Results: Seven (3.2%) recipients were found from a cohort of 219 pediatric patients. Two of the seven patients had multilocular HCC in cirrhosis. Disease recurrence or graft loss did not occur in any patient. Two patients (male, siblings) had persistently elevated liver parameters but showed excellent liver function. Patient and graft survival during long-term follow-up was 100%, and no severe extrahepatic manifestations requiring hospitalization or surgery occurred. We noted a low complication rate during long-term follow-up and excellent patient outcome. Conclusions: PFIC1 long-term follow-up after LT shows promising results for this rare disease. In particular, the clinical relevance of extrahepatic manifestations seems acceptable, and graft function seems to be barely affected. Further multicenter studies are needed to analyze the clinically inhomogeneous presentation and to better understand the courses after LT.

A Report of 2 Infant Siblings with Progressive Intrahepatic Familial Cholestasis Type 1 and a Novel Homozygous Mutation in the ATP8B1 Gene Treated with Partial External Biliary Diversion and Liver Transplant

Case series

Patients: Male • Male / (siblings)

Final Diagnosis: Progressive intrahepatic familial cholestasis type 1 (PFIC-1)

Symptoms: Jaundice

Medication: —

Clinical Procedure: —

Specialty: Transplantology

Phenotypic and Molecular Characteristics of Children with Progressive Familial Intrahepatic Cholestasis in South China

PURPOSE

Progressive familial intrahepatic cholestasis (PFIC) is a rare genetic autosomal recessive disease caused by mutations in ATP8B1, ABCB11 or ABCB4. Mutational analysis of these genes is a reliable approach to identify the disorder.

METHODS

We collected and analyzed relevant data related to clinical diagnosis, biological investigation, and molecular determination in nine children carrying these gene mutations, who were from unrelated families in South China.

RESULTS

Of the nine patients (five males, four females) with PFIC, one case of PFIC1, four cases of PFIC2, and four cases of PFIC3 were diagnosed. Except in patient no. 8, jaundice and severe pruritus were the major clinical signs in all forms. γ-glutamyl transpeptidase was low in patients with PFIC1/PFIC2, and remained mildly elevated in patients with PFIC3. We identified 15 different mutations, including nine novel mutations (p.R470HfsX8, p.Q794X and p.I1170T of ABCB11 gene mutations, p.G319R, p.A1047P, p.G1074R, p.T830NfsX11, p.A1047PfsX8 and p.N1048TfsX of ABCB4 gene mutations) and six known mutations (p.G446R and p.F529del of ATP8B1 gene mutations, p.A588V, p.G1004D and p.R1057X of ABCB11 gene mutations, p.P479L of ABCB4 gene mutations). The results showed that compared with other regions, these three types of PFIC genes had different mutational spectrum in China.

CONCLUSION

The study expands the genotypic spectrum of PFIC. We identified nine novel mutations of PFIC and our findings could help in the diagnosis and treatment of this disease.

Surgical diversion of enterohepatic circulation in pediatric cholestasis

Progressive familial intrahepatic cholestasis (PFIC) and Alagille syndrome (AS) are conditions caused by either an autosomal recessive or an autosomal dominant genetic defect, and they are both characterized by cholestasis, jaundice, and severe debilitating pruritus refractory to medical management. Before the advent of liver transplantation, most PFIC patients would die from end-stage liver disease in the first decade of life. Although liver transplantation has led to patients' survival, disease recurrence (PFIC-2) and severe extra-hepatic manifestations of the disease (PFIC-1) occurred post transplant. In the late 1980s, Whitington described the use of partial external biliary diversion in PFIC and AS patients as a successful way to improve symptoms and decrease circulating bile acid serum concentrations. Since then, other diversion techniques have been described (ileal exclusion and partial internal biliary diversion). These techniques have the benefit of avoiding a stoma, but equivalent results have not been demonstrated (recurrence of cholestasis after ileal exclusion, limited follow up after internal biliary diversion). Overall, studies have showed that biliary diversions in children with cholestasis are safe procedures with low morbidity and mortality, and that they can reduce inflammation and ongoing liver injury, therefore delaying or avoiding the need for liver transplantation in some patients.

Novel ATP8B1 Gene Mutations in a Child with Progressive Familial Intrahepatic Cholestasis Type 1

Progressive familial intrahepatic cholestasis (PFIC) is a group of severe genetic disorders, inherited in an autosomal recessive manner, causing cholestasis of hepatocellular origin, later progressing to biliary cirrhosis and liver failure. This is the first report of PFIC type 1 with novel compound heterozygous mutations in Korea. The patient was presented with intrahepatic cholestasis, a normal level of serum γ-glutamyl transferase, steatorrhea, and growth failure. Genetic testing of this patient revealed novel compound heterozygous mutations (p.Glu585Ter and p.Leu749Pro) in the ATP8B1 gene. After a liver transplantation at age 19 months, the patient developed severe post-transplant steatohepatitis.

Reversal of secondary protein-losing enteropathy after surgical revision of a jejunal Roux-en-Y loop in a patient after liver transplantation

Secondary protein-losing enteropathy (PLE) is a rare complication following pediatric liver transplantation (LT), mostly related to venous outflow obstruction of the liver. Here, we discuss a thus far unknown cause of secondary PLE following pediatric LT. A 7-month-old boy underwent LT with biliary anastomosis using a Roux-en-Y jejunal loop. Eleven months later he developed PLE. Routine diagnostic workup was negative. No hepatic outflow obstruction was detected during catheterization. Although the hepatic venous pressure gradient was slightly increased (10 mm Hg), there were no clinical signs of portal hypertension. Albumin scintigraphy with specific early recordings suggested focal albumin intestinal entry in the jejunal Roux-en-Y loop. Local bacterial overgrowth or local lymphangiectasia, possibly due to (venous) congestion, was considered. Treatment with metronidazole did not improve albumin loss. Next, surgical revision of the jejunal Roux-en-Y loop was performed. The explanted loop contained a small abnormal area with a thin hyperemic mucosa, near the former anastomosis. Histopathological analysis showed changes both in the blood vessels and the lymphatic vessels with focal deeper chronic active inflammation resulting in congestion of vessels, hampering lymphatic outflow leading to lymphangiectasia and patchy distortion of lymphatic vessels. Following surgical revision, secondary PLE disappeared, up to now, 1.5 year post revision.

Progressive Familial Intrahepatic Cholestasis in Korea: A Clinicopathological Study of Five Patients

BACKGROUND

Progressive familial intrahepatic cholestasis (PFIC) is a heterogeneous group of autosomal recessive liver diseases that present as neonatal cholestasis. Little is known of this disease in Korea.

METHODS

The records of five patients histologically diagnosed with PFIC, one with PFIC1 and four with PFIC2, by liver biopsy or transplant were reviewed, and ATP8B1 and ABCB11 mutation status was analyzed by direct DNA sequencing. Clinicopathological characteristics were correlated with genetic mutations.

RESULTS

The first symptom in all patients was jaundice. Histologically, lobular cholestasis with bile plugs was the main finding in all patients, whereas diffuse or periportal cholestasis was identified only in patients with PFIC2. Giant cells and ballooning of hepatocytes were observed in three and three patients with PFIC2, respectively, but not in the patient with PFIC1. Immunostaining showed total loss of bile salt export pump in two patients with PFIC2 and focal loss in two. Lobular and portal based fibrosis were more advanced in PFIC2 than in PFIC1. ATP8B1 and ABCB11 mutations were identified in one PFIC1 and two PFIC2 patients, respectively. One PFIC1 and three PFIC2 patients underwent liver transplantation (LT). At age 7 months, one PFIC2 patient was diagnosed with concurrent hepatocellular carcinoma and infantile hemangioma in an explanted liver. The patient with PFIC1 developed steatohepatitis after LT. One patient showed recurrence of PFIC2 after 10 years and underwent LT.

CONCLUSIONS

PFIC is not rare in patients with neonatal cholestasis of unknown origin. Proper clinicopathologic correlation and genetic testing can enable early detection and management.

Familial intrahepatic cholestasis: New and wide perspectives

BACKGROUND

Progressive familial intrahepatic cholestasis (PFIC) includes autosomal recessive cholestatic rare diseases of childhood.

AIMS

To update the panel of single genes mutations involved in familial cholestasis.

METHODS

PubMed search for "familial intrahepatic cholestasis" alone as well as in combination with other key words was performed considering primarily original studies and meta-analyses.

RESULTS

PFIC1 involves ATP8B1 gene encoding for aminophospholipid flippase FIC1. PFIC2 includes ABCB11 gene, encoding for protein functioning as bile salt export pump. PFIC3 is due to mutations of ABCB4 gene responsible for the synthesis of class III multidrug resistance P-glycoprotein flippase. PFIC4 and PFIC5 involve tight junction protein-2 gene and NR1H4 gene encoding for farnesoid X receptor. Benign Intrahepatic Cholestasis, Intrahepatic Cholestasis of Pregnancy and Low-phospholipid-associated cholelithiasis involve the same genes and are characterized by intermittent attacks of cholestasis, no progression to cirrhosis, reversible pregnancy-specific cholestasis and cholelithiasis in young people. Blood and liver tissue levels of bile-excreted drugs can be influenced by the presence of mutations in PFIC genes, causing drug-induced cholestasis. Mutations in PFIC genes might increase the risk of liver cancer.

CONCLUSION

There is a high proportion of unexplained cholestasis potentially caused by specific genetic pathophysiologic pathways. The use of next generation sequencing and whole-exome sequencing could improve the diagnostic process in this setting.

Liver Transplantation for Progressive Familial Intrahepatic Cholestasis

BACKGROUND Progressive familial intrahepatic cholestasis (PFIC) is an autosomal recessive inherited disease that disrupts the genes for bile formation. Liver transplantation (LT) is the only effective treatment for PFIC patients with end-stage liver disease. We describe our experience in terms of clinical characteristics, complications, and outcome of LT for PFIC. CASE REPORT The data of 5 pediatric PFIC patients recipients (3 PFIC1, 1 PFIC2, and 1 PFIC3) who received LT at our Liver Transplant Center from June 2013 to February 2017 were retrospectively analyzed. Four patients received liver transplantation from donation after cardiac death (DCD) donors. One patient received a living donor liver transplantation (LDLT). All the LT recipients received an immunosuppressive regimen of tacrolimus (FK 506) + methylprednisolone + mycophenolate mofetil (MMF). Diarrhea did not improve in 2 PFIC1 patients after LT, and they both developed steatohepatitis several months after LT. The other PFIC1 patient received ABO blood group incompatible LT and developed biliary complications and a severe Epstein-Barr virus infection; this patient underwent endoscopic retrograde cholangiopancreatography. She recovered after treatment with ganciclovir and reduction of tacrolimus dosage. The PFIC2 patient had abnormal liver function 19 months after LT, and recovered after administration of increased dosage of immunosuppressant agents. Liver function in the PFIC3 patient was normal during 2-year follow-up. CONCLUSIONS Liver transplantation is an effective treatment in PFIC patients. However, PFIC1 patients may develop aggravated diarrhea and steatohepatitis after LT. PFIC2 and PFIC3 patients have good outcomes after LT.

Spectrum of genomic variations in Indian patients with progressive familial intrahepatic cholestasis

BACKGROUND

Progressive familial intrahepatic cholestasis (PFIC) is caused by variations in ATP8B1, ABCB11 or ABCB4 genes. Data on genetic variations in Indian patients with PFIC are lacking.

METHODS

Coding and splice regions of the three genes were sequenced in unrelated Indian children with PFIC phenotype. The variations identified were looked for in parents, 30 healthy persons and several variation databases, and their effect was assessed in-silico.

RESULTS

Among 25 children (aged 1-144 months), nine (36%) had unique major genomic variations (ATP8B1: 4, ABCB11: 3 and ABCB4: 2). Seven had homozygous variations, which were assessed as 'pathogenic' or 'likely pathogenic'. These included: (i) four amino acid substitutions (ATP8B1: c.1660G > A/p.Asp554Asn and c.2941G > A/p.Glu981Lys; ABCB11: c.548 T > C/p.Met183Thr; ABCB4: c.431G > A/p.Arg144Gln); (ii) one 3-nucleotide deletion causing an amino acid deletion (ATP8B1: c.1587_1589delCTT/p.Phe529del); (iii) one single-nucleotide deletion leading to frame-shift and premature termination (ABCB11: c.1360delG/p.Val454Ter); and (iv) a complex inversion of 4 nucleotides with a single-nucleotide insertion leading to frame-shift and premature termination (ATP8B1: c.[589_592inv;592_593insA]/p.Gly197LeufsTer10). Two variations were found in heterozygous form: (i) a splice-site variation likely to cause abnormal splicing (ABCB11: c.784 + 1G > C), and (ii) a nucleotide substitution that created a premature stop codon (ABCB4: c.475C > T/p.Arg159Ter); these were considered as variations of uncertain significance. Three of the nine variations were novel.

CONCLUSIONS

Nine major genomic variations, including three novel ones, were identified in nearly one-third  of Indian children with PFIC. No variation was identified in nearly two-thirds of patients, who may have been related to variations in promoter or intronic regions of the three PFIC genes, or in other bile-salt transport genes.

Biliary drainage as treatment for allograft steatosis following liver transplantation for PFIC-1 disease: A single-center experience

Development of macrovesicular steatosis post-LT in patients with PFIC-1 is increasingly being observed, with the etiology not fully understood. We highlight successful and effective EBD for reversal of allograft steatosis in 2 patients with PFIC-1 disease and discuss our experience with internal biliary diversion in this patient population.

Outcomes of surgical management of familial intrahepatic cholestasis 1 and bile salt export protein deficiencies

Progressive familial intrahepatic cholestasis (PFIC) with normal circulating gamma‐glutamyl transpeptidase levels can result from mutations in the ATP8B1 gene (encoding familial intrahepatic cholestasis 1 [FIC1] deficiency) or the ABCB11 gene (bile salt export protein [BSEP] deficiency). We investigated the outcomes of partial external biliary diversion, ileal exclusion, and liver transplantation in these two conditions. We conducted a retrospective multicenter study of 42 patients with FIC1 deficiency (FIC1 patients) and 60 patients with BSEP deficiency (BSEP patients) who had undergone one or more surgical procedures (57 diversions, 6 exclusions, and 57 transplants). For surgeries performed prior to transplantation, BSEP patients were divided into two groups, BSEP‐common (bearing common missense mutations D482G or E297G, with likely residual function) and BSEP‐other. We evaluated clinical and biochemical outcomes in these patients. Overall, diversion improved biochemical parameters, pruritus, and growth, with substantial variation in individual response. BSEP‐common or FIC1 patients survived longer after diversion without developing cirrhosis, being listed for or undergoing liver transplantation, or dying, compared to BSEP‐other patients. Transplantation resolved cholestasis in all groups. However, FIC1 patients commonly developed hepatic steatosis, diarrhea, and/or pancreatic disease after transplant accompanied by biochemical abnormalities and often had continued poor growth. In BSEP patients with impaired growth, this generally improved after transplantation. Conclusion: Diversion can improve clinical and biochemical status in FIC1 and BSEP deficiencies, but outcomes differ depending on genetic etiology. For many patients, particularly BSEP‐other, diversion is not a permanent solution and transplantation is required. Although transplantation resolves cholestasis in patients with FIC1 and BSEP deficiencies, the overall outcome remains unsatisfactory in many FIC1 patients; this is mainly due to extrahepatic manifestations. (Hepatology Communications 2018;2:515‐528)

Living Donor Liver Transplantation for Progressive Familial Intrahepatic Cholestasis Type 1: Two Reported Cases

BACKGROUND

Progressive familial intrahepatic cholestasis type 1 (PFIC1) is an inherited disease characterized by cholestatic features. We report two patients with PFIC1 who underwent liver retransplantation.

CASE REPORT

One patient was a 3-year-old female who underwent liver transplantation for PFIC1. She presented with severe diarrhea and fatty liver, and went into liver failure. She therefore underwent liver retransplantation and external biliary diversion 8 years after the initial liver transplantation. The explanted liver was histologically diagnosed with chronic rejection. Her intractable diarrhea stopped after the retransplantation. She was diagnosed with a fatty liver 8 months after the retransplantation and died 4 years after retransplantation due to bleeding from an ileostomy. The other patient was a 3-year-old male. This patient underwent liver retransplantation due to liver cirrhosis caused by steatohepatitis 9 years after the initial liver transplantation. The biliary tract was not diverted. He also experienced severe diarrhea after the retransplantation and requires home parenteral nutrition due to an eating disorder.

CONCLUSIONS

Liver transplantation is the only treatment to resolve life-threatening issues due to PFIC1, but requires further improvement as a therapeutic modality.

Analysis of surgical interruption of the enterohepatic circulation as a treatment for pediatric cholestasis

To evaluate the efficacy of nontransplant surgery for pediatric cholestasis, 58 clinically diagnosed children, including 20 with Alagille syndrome (ALGS), 16 with familial intrahepatic cholestasis-1 (FIC1), 18 with bile salt export pump (BSEP) disease, and 4 others with low γ-glutamyl transpeptidase disease (levels <100 U/L), were identified across 14 Childhood Liver Disease Research Network (ChiLDReN) centers. Data were collected retrospectively from individuals who collectively had 39 partial external biliary diversions (PEBDs), 11 ileal exclusions (IEs), and seven gallbladder-to-colon (GBC) diversions. Serum total bilirubin decreased after PEBD in FIC1 (8.1 ± 4.0 vs. 2.9 ± 4.1 mg/dL, preoperatively vs. 12-24 months postoperatively, respectively; P = 0.02), but not in ALGS or BSEP. Total serum cholesterol decreased after PEBD in ALGS patients (695 ± 465 vs. 457 ± 319 mg/dL, preoperatively vs. 12-24 months postoperatively, respectively; P = 0.0001). Alanine aminotransferase levels increased in ALGS after PEBD (182 ± 70 vs. 260 ± 73 IU/L, preoperatively vs. 24 months; P = 0.03), but not in FIC1 or BSEP. ALGS, FIC1, and BSEP patients experienced less severely scored pruritus after PEBD (ALGS, 100% vs. 9% severe; FIC1, 64% vs. 10%; BSEP, 50% vs. 20%, preoperatively vs. >24 months postoperatively, respectively; P < 0.001). ALGS patients experienced a trend toward greater freedom from xanthomata after PEBD. There was a trend toward decreased pruritus in FIC1 after IE and GBC. Vitamin K supplementation increased in ALGS after PEBD (33% vs. 77%; P = 0.03). Overall, there were 15 major complications after surgery. Twelve patients (3 ALGS, 3 FIC1, and 6 BSEP) subsequently underwent liver transplantation.

CONCLUSION

This was a multicenter analysis of nontransplant surgical approaches to intrahepatic cholestasis. Approaches vary, are well tolerated, and generally, although not uniformly, result in improvement of pruritus and cholestasis. (Hepatology 2017;65:1645-1654).

Pediatric Liver Transplantation: Unique Concerns for the Critical Care Team

Liver transplantation originated in children more than 50 years ago, and these youngest patients, while comprising the minority of liver transplant recipients nationwide, can have some of the best and most rewarding outcomes. The indications for liver transplantation in children are generally more diverse than those seen in adult patients. This diversity in underlying cause of disease brings with it increased complexity for all who care for these patients. Children, still being completely dependent on others for survival, also require a care team that is able and ready to work with parents and family in addition to the patient at the center of the process. In this review, we aim to discuss diagnoses of particular uniqueness or importance to pediatric liver transplantation. We also discuss the evaluation of a pediatric patient for liver transplant, the system for allocating them a new liver, and also touch on postoperative concerns that are unique to the pediatric population.

Clinical Variability After Partial External Biliary Diversion in Familial Intrahepatic Cholestasis 1 Deficiency

OBJECTIVES

Familial intrahepatic cholestasis 1 (FIC1) deficiency is caused by a mutation in the ATP8B1 gene. Partial external biliary diversion (PEBD) is pursued to improve pruritus and arrest disease progression. Our aim is to describe clinical variability after PEBD in FIC1 disease.

METHODS

We performed a single-center, retrospective review of genetically confirmed FIC1 deficient patients who received PEBD. Clinical outcomes after PEBD were cholestasis, pruritus, fat-soluble vitamin supplementation, growth, and markers of disease progression that included splenomegaly and aspartate aminotransferase-to-platelet ratio index.

RESULTS

Eight patients with FIC1 disease and PEBD were included. Mean follow-up was 32 months (range 15-65 months). After PEBD, total bilirubin was <2 mg/dL in all patients at 8 months after surgery, but 7 of 8 subsequently experienced a total of 15 recurrent cholestatic events. Subjective assessments of pruritus demonstrated improvement, but itching exacerbation occurred during cholestatic episodes. High-dose fat-soluble vitamin supplementation persisted, with increases needed during cholestatic episodes. Weight z scores improved (-3.4 to -1.65, P < 0.01). Splenomegaly did not worsen or develop and 1 patient developed an aminotransferase-to-platelet ratio index score of >0.7 suggesting development of fibrosis 24 months after PEBD.

CONCLUSIONS

Clinical variability is evident among genetically defined FIC1 deficient patients after PEBD, even among those with identical mutations. Recurrent, self-limited episodes of cholestasis and pruritus are reminiscent of the benign recurrent intrahepatic cholestasis phenotype. Despite diversion of bile from the intestinal lumen, weight gain improved while fat-soluble vitamin requirements persisted. Significant progression of liver disease was not evident during follow-up.

Current and future therapies for inherited cholestatic liver diseases

Familial intrahepatic cholestasis (FIC) comprises a group of rare cholestatic liver diseases associated with canalicular transport defects resulting predominantly from mutations in ATP8B1, ABCB11 and ABCB4. Phenotypes range from benign recurrent intrahepatic cholestasis (BRIC), associated with recurrent cholestatic attacks, to progressive FIC (PFIC). Patients often suffer from severe pruritus and eventually progressive cholestasis results in liver failure. Currently, first-line treatment includes ursodeoxycholic acid in patients with ABCB4 deficiency (PFIC3) and partial biliary diversion in patients with ATP8B1 or ABCB11 deficiency (PFIC1 and PFIC2). When treatment fails, liver transplantation is needed which is associated with complications like rejection, post-transplant hepatic steatosis and recurrence of disease. Therefore, the need for more and better therapies for this group of chronic diseases remains. Here, we discuss new symptomatic treatment options like total biliary diversion, pharmacological diversion of bile acids and hepatocyte transplantation. Furthermore, we focus on emerging mutation-targeted therapeutic strategies, providing an outlook for future personalized treatment for inherited cholestatic liver diseases.

Outcomes following partial external biliary diversion in patients with progressive familial intrahepatic cholestasis

BACKGROUND/PURPOSE

PFIC is a family of bile acid (BA) transport disorders that may result in serious liver disease requiring transplantation. We reviewed our experience with PEBD as a method to improve liver function and avoid transplantation.

METHODS

All patients with PFIC were reviewed. Outcomes included changes in serum BA, conversion to ileal bypass (IB), and survival without transplantation. Statistics were obtained using paired t-test and Wilcoxon test.

RESULTS

Thirty-five patients with PFIC were identified. Data were available in 24. Twenty-four children (12 males) underwent PEBD: 10 PFIC-1, 13 PFIC-2, and one PFIC-3. BA levels decreased in PFIC-1 patients (1724±3215 to 11±6μmol/L, P=0.03) and in the single PFIC-3 patient (821 to 11.2μmol/L), but not significantly in PFIC-2 patients (193±99 to 141±118μmol/L, P=0.15). Seven patients were converted to IB. There were no significant changes in BA levels following conversion. Five-year transplant-free survival was 100% in PFIC-1 and PFIC-3, but only 38% (5/13) in PFIC-2 (P=0.004).

CONCLUSION

PEBD is an effective procedure to reduce total BA levels and improve symptoms in PFIC patients. However, it appears to be less efficacious in the PFIC-2 group. The higher BA levels could contribute to ongoing liver damage, and thus a higher transplant rate in PFIC-2 patients.

LEVEL OF EVIDENCE

Level IV.

Total internal biliary diversion during liver transplantation for type 1 progressive familial intrahepatic cholestasis: a novel approach

LT for PFIC type 1 is often complicated by postoperative diarrhea and recurrent graft steatosis. A 26-month-old female child with cholestatic jaundice, pruritus, diarrhea, and growth retardation revealed total bilirubin 9.1 mg/dL, gamma-glutamyl transpeptidase 64 IU/L, and TBA 295.8 μmol/L. Genetic analysis confirmed ATP8B1 defects. A LT (segment 2, 3 graft) from the heterozygous father was performed. Biliary diversion was performed by a 35-cm jejunum conduit between the graft hepatic duct and the mid-transverse colon. Stools became pigmented immediately. Follow-up at 138 days revealed resolution of jaundice and pruritus and soft-to-hard stools (6-8 daily). Radioisotope hepato-biliary scintigraphy (days 26, 68, and 139) confirmed unobstructed bile drainage into the colon (t_1/2 34, 27, and 19 minutes, respectively). Contrast meal follow-through at day 62 confirmed the absence of any colo-jejuno-hepatic reflux. At 140 days, contrast follow-through via the biliary stent revealed patent jejuno-colonic anastomosis and satisfactory transit. Graft biopsy at LT, 138 days, and 9 months follow-up revealed comparable grades of macrovesicular steatosis (<20%). TIBD during LT may be a clinically effective stoma-free biliary diversion and may prevent recurrent graft steatosis following LT for PFIC type 1.

A 10-Year united network for organ sharing review of mortality and risk factors in young children awaiting liver transplantation

Young children < 2 years of age with chronic end-stage liver disease (YC2) are a uniquely vulnerable group listed for liver transplantation, characterized by a predominance of biliary atresia (BA). To investigate wait-list mortality, associated risk factors, and outcomes of YC2, we evaluated United Network for Organ Sharing registry data from April 2003 to March 2013 for YC2 listed for deceased donor transplant (BA = 994; other chronic liver disease [CLD] = 221). Overall, wait-list mortality among YC2 was 12.4% and posttransplant mortality was 8%, accounting for an overall postlisting mortality of 19.6%. YC2 demonstrated 12.2%, 18.7%, and 20.6% wait-list mortality by 90, 180, and 270 days, respectively. YC2 with CLD demonstrated significantly higher wait-list mortality compared with BA among YC2 (23.9% versus 9.8%; P < 0.05). Multivariate analyses revealed that listing Pediatric End-Stage Liver Disease [PELD] > 21 (hazard ratio [HR], 3.2; 95% confidence interval [CI], 1.6-6.5), lack of exception (HR, 5.8; 95% CI, 2.8-11.8), listing height < 60.6 cm (HR, 2.1; 95% CI, 1.4-3.1), listing weight  > 10 kg (HR, 3.8; 95% CI, 1.5-9.2), and initial creatinine > 0.5 (HR, 6.8; 95% CI, 3.4-13.5) were independent risk factors for YC2 wait-list mortality (P < 0.005 for all). Adjusting for all variables, the risk of death among CLD patients was 2 (95% CI, 1.3-3.1) times greater than patients with BA + surgery (presumed Kasai). Furthermore, the risk of death in BA without surgery was 1.9 (95% CI, 1‐3.4) times greater than BA with presumed Kasai. Our data highlight unacceptably high wait-list and early post-liver transplant mortality in YC2 not predicted by PELD and suggest key risk factors deserving of further study in this age group. Liver Transplantation 22 1584-1592 2016 AASLD.

Progressive Familial Intrahepatic Cholestasis (PFIC) in Indian Children: Clinical Spectrum and Outcome

OBJECTIVE

To study the clinical and laboratory profile of children with progressive familial intrahepatic cholestasis (PFIC) and evaluate their outcome.

METHODS

The study is a retrospective review of all cases diagnosed with PFIC between January 2011 and July 2015. All children underwent histopathological examination and immunostaining. Management was done as per institute's protocol.

RESULTS

There were a total of 24 PFIC cases (PFIC 1-2, PFIC 2-19, PFIC 3-3). Eleven presented as neonatal cholestasis, whereas 13 others presented after 6 months of life. Median age of presentation in PFIC 2 was 5.5 months with a time lag of 13 months in diagnosis. PFIC 1 and 2 presented in infancy, whereas PFIC 3 presented late. Familial clustering was seen in 12 of 24 cases. Pruritus resolved with medical management in two-thirds of cases, 3 cases required biliary diversion (BD) with dramatic improvement. One child improved after liver transplantation.

CONCLUSIONS

PFIC accounts for 8% of neonatal cholestasis and 34% of cholestasis in older children with PFIC 2 being the commonest subtype. Medical therapy is successful in majority. Partial internal BD should be offered to non-cirrhotic low gamma glutamyl transferase PFIC with intractable pruritus. Progression to cirrhosis may be prevented or delayed by early diagnosis and timely intervention.

[Clinical feature and ATP8B1 mutation analysis of a patient with progressive familial intrahepatic cholestasis type I]

Progressive familial intrahepatic cholestasis type I (PFIC1) is an autosomal recessive disorder caused by biallelic mutations of ATP8B1 gene, with progressive cholestasis as the main clinical manifestation. This paper reports the clinical and genetic features of a PFIC1 patient definitely diagnosed by ATP8B1 genetic analysis. The patient, a boy aged 14 months, was referred to the hospital with the complaint of jaundiced skin and sclera over 10 months. The patient had been managed in different hospitals, but the therapeutic effects were unsatisfactory due to undetermined etiology. On physical examination, hepatosplenomegaly was discovered in addition to jaundice of the skin and sclera. The liver was palpable 4 cm below the right subcostal margin and 2 cm below the xiphoid while the spleen 2 cm below the left subcostal margin. The liver function test revealed elevated levels of serum total bile acids, bilirubin, and transaminases; however, the γ-glutamyl transferase level was normal. The diagnosis was genetic cholestasis of undetermined origin. At the age of 1 year and 8 months, a Roux-en-Y cholecystocolonic bypass operation was performed, and thereafter the jaundice disappeared. At 5 years and 1 month, via whole genome sequencing analysis and Sanger sequencing confirmation, the boy was found to be a homozygote of mutation c.2081T>A(p.I694N) of ATP8B1 gene, and thus PFIC1 was definitely diagnosed. The boy was followed up until he was 6 years, and jaundice did not recur, but the long-term outcome remains to be observed.

Genetics and Molecular Modeling of New Mutations of Familial Intrahepatic Cholestasis in a Single Italian Center

Familial intrahepatic cholestases (FICs) are a heterogeneous group of autosomal recessive disorders of childhood that disrupt bile formation and present with cholestasis of hepatocellular origin. Three distinct forms are described: FIC1 and FIC2, associated with low/normal GGT level in serum, which are caused by impaired bile salt secretion due to defects in ATP8B1 encoding the FIC1 protein and defects in ABCB11 encoding bile salt export pump protein, respectively; FIC3, linked to high GGT level, involves impaired biliary phospholipid secretion due to defects in ABCB4, encoding multidrug resistance 3 protein. Different mutations in these genes may cause either a progressive familial intrahepatic cholestasis (PFIC) or a benign recurrent intrahepatic cholestasis (BRIC). For the purposes of the present study we genotyped 27 children with intrahepatic cholestasis, diagnosed on either a clinical or histological basis. Two BRIC, 23 PFIC and 2 BRIC/PFIC were identified. Thirty-four different mutations were found of which 11 were novel. One was a 2Mb deletion (5’UTR- exon 18) in ATP8B1. In another case microsatellite analysis of chromosome 2, including ABCB11, showed uniparental disomy. Two cases were compound heterozygous for BRIC/PFIC2 mutations. Our results highlight the importance of the pathogenic role of novel mutations in the three genes and unusual modes of their transmission.

Hypothyroidism Associated with ATP8B1 Deficiency

OBJECTIVE

To examine whether hypothyroidism is an extrahepatic feature of ATPase, aminophospholipid transporter, class I, type 8B, member 1 (ATP8B1) deficiency.

STUDY DESIGN

Children with normal γ-glutamyltransferase cholestasis (n = 47; 13 patients with ATP8B1 deficiency, 19 with ATP-binding cassette, subfamily B (MDR/TAP), member 11 (ABCB11) deficiency, and 15 without either ATP8B1 or ABCB11 mutations) were enrolled. Clinical information and thyroid function test results were retrospectively retrieved from clinical records and compared. Hypothyroidism was diagnosed by clinical-biochemistry criteria (thyroid function test results).

RESULTS

Three out of 13 patients with ATP8B1 deficiency were diagnosed as hypothyroid and 2 as subclinically hypothyroid. The frequency of hypothyroidism and subclinical hypothyroidism was significantly higher than in patients with ABCB11 deficiency (5/13 vs 0/19, P = .006) and in patients without ATP8B1 or ABCB11 mutations (5/13 vs 0/15, P = .013). Thyroid function test results normalized after hormone replacement in all 5 patients, with no relief of cholestasis.

CONCLUSIONS

As hypothyroidism can be another extrahepatic feature of ATP8B1 deficiency, thyroid function should be monitored in these patients.

ATP8B1 and ATP11C: Two Lipid Flippases Important for Hepatocyte Function

P4 ATPases are lipid flippases and transport phospholipids from the exoplasmic to the cytosolic leaflet of biological membranes. Lipid flipping is important for the biogenesis of transport vesicles. Recently it was shown that loss of the P4 ATPases ATP8B1 and ATP11C are associated with severe Cholestatic liver disease. Mutation of ATP8B1 cause progressive familial Intrahepatic Cholestasis type 1 (PFIC1)and benign recurrent intrahepatic cholestasis type 1 (BRIC 1). From our observations we hypothesized that ATP8B1 deficiency causes a phospholipids randomization at the canalicular membrane, which results in extraction of cholesterol due to increase sensitivity of the canalicular membrane. Deficiency of ATP11C causes conjugated hyperbilirubinemia. In our preliminary result we observed accumulation of unconjugated bile salts in Atp11c deficient mice probably because of regulation in the expression or function of OATP1B2. Similar to ATP8B1, ATP11C have regulation on membrane transporters.

Analysis of aberrant pre-messenger RNA splicing resulting from mutations in ATP8B1 and efficient in vitro rescue by adapted U1 small nuclear RNA

ATP8B1 deficiency is a severe autosomal recessive liver disease resulting from mutations in the ATP8B1 gene characterized by a continuous phenotypical spectrum from intermittent (benign recurrent intrahepatic cholestasis; BRIC) to progressive familial intrahepatic cholestasis (PFIC). Current therapeutic options are insufficient, and elucidating the molecular consequences of mutations could lead to personalized mutation-specific therapies. We investigated the effect on pre-messenger RNA splicing of 14 ATP8B1 mutations at exon-intron boundaries using an in vitro minigene system. Eleven mutations, mostly associated with a PFIC phenotype, resulted in aberrant splicing and a complete absence of correctly spliced product. In contrast, three mutations led to partially correct splicing and were associated with a BRIC phenotype. These findings indicate an inverse correlation between the level of correctly spliced product and disease severity. Expression of modified U1 small nuclear RNAs (snRNA) complementary to the splice donor sites strongly improved or completely rescued splicing for several ATP8B1 mutations located at donor, as well as acceptor, splice sites. In one case, we also evaluated exon-specific U1 snRNAs that, by targeting nonconserved intronic sequences, might reduce possible off-target events. Although very effective in correcting exon skipping, they also induced retention of the short downstream intron.

CONCLUSION

We systematically characterized the molecular consequences of 14 ATP8B1 mutations at exon-intron boundaries associated with ATP8B1 deficiency and found that the majority resulted in total exon skipping. The amount of correctly spliced product inversely correlated with disease severity. Compensatory modified U1 snRNAs, complementary to mutated donor splice sites, were able to improve exon definition very efficiently and could be a novel therapeutic strategy in ATP8B1 deficiency as well as other genetic diseases.

Mutations in TJP2, encoding zona occludens 2, and liver disease

Progressive familial intrahepatic cholestasis is a clinical description of a phenotype, which we now realize has several different genetic aetiologies. The identification of the underlying genetic defects has helped to elucidate important aspects of liver physiology. The latest addition to this family of diseases is tight junction protein 2 (TJP2) deficiency. This protein is also known as zona occludens 2 (ZO-2). The patients, so far presented, all have homozygous, protein-truncating mutations. A complete absence of this protein was demonstrated. These children presented with severe liver disease, some manifesting extrahepatic features. By contrast, embryonic-lethality was seen in ZO-2 knockout mice. This discovery highlights important differences, not just between species, but also between different epithelia in humans. This commentary discusses the recently presented findings, and some of the issues that arise.

The lipid flippase heterodimer ATP8B1-CDC50A is essential for surface expression of the apical sodium-dependent bile acid transporter (SLC10A2/ASBT) in intestinal Caco-2 cells

Deficiency of the phospholipid flippase ATPase, aminophospholipid transporter, class I, type 8B, member 1 (ATP8B1) causes progressive familial intrahepatic cholestasis type 1 (PFIC1) and benign recurrent intrahepatic cholestasis type 1 (BRIC1). Apart from cholestasis, many patients also suffer from diarrhea of yet unknown etiology. Here we have studied the hypothesis that intestinal ATP8B1 deficiency results in bile salt malabsorption as a possible cause of PFIC1/BRIC1 diarrhea. Bile salt transport was studied in ATP8B1-depleted intestinal Caco-2 cells. Apical membrane localization was studied by a biotinylation approach. Fecal bile salt and electrolyte contents were analyzed in stool samples of PFIC1 patients, of whom some had undergone biliary diversion or liver transplantation. Bile salt uptake by the apical sodium-dependent bile salt transporter solute carrier family 10 (sodium/bile acid cotransporter), member 2 (SLC10A2) was strongly impaired in ATP8B1-depleted Caco-2 cells. The reduced SLC10A2 activity coincided with strongly reduced apical membrane localization, which was caused by impaired apical membrane insertion of SLC10A2. Moreover, we show that endogenous ATP8B1 exists in a functional heterodimer with transmembrane protein 30A (CDC50A) in Caco-2 cells. Analyses of stool samples of post-transplant PFIC1 patients demonstrated that bile salt content was not changed, whereas sodium and chloride concentrations were elevated and potassium levels were decreased. The ATP8B1-CDC50A heterodimer is essential for the apical localization of SLC10A2 in Caco-2 cells. Diarrhea in PFIC1/BRIC1 patients has a secretory origin to which SLC10A2 deficiency may contribute. This results in elevated luminal bile salt concentrations and consequent enhanced electrolyte secretion and/or reduced electrolyte resorption.

The adolescent liver transplant patient

The rapid development of new diagnostic tests and improved therapy, especially the success of liver transplantation, has changed the outcome for children with liver disease, many of whom survive into adolescence without liver transplantation. The indications for transplantation in adolescence are similar to pediatric indications and reflect the medical advances made in this specialty that allow later transplantation. These young people need a different approach to management that involves consideration of their physical and psychological stage of development. A focused approach to their eventual transition to adult care is essential for long-term survival and quality of life.

Progressive familial intrahepatic cholestasis

Progressive familial intrahepatic cholestasis (PFIC) is a group of rare disorders which are caused by defect in bile secretion and present with intrahepatic cholestasis, usually in infancy and childhood. These are autosomal recessive in inheritance. The estimated incidence is about 1 per 50,000 to 1 per 100,000 births, although exact prevalence is not known. These diseases affect both the genders equally and have been reported from all geographical areas. Based on clinical presentation, laboratory findings, liver histology and genetic defect, these are broadly divided into three types-PFIC type 1, PFIC type 2 and PFIC type 3. The defect is in ATP8B1 gene encoding the FIC1 protein, ABCB 11 gene encoding BSEP protein and ABCB4 gene encoding MDR3 protein in PFIC1, 2 and 3 respectively. The basic defect is impaired bile salt secretion in PFIC1/2 whereas in PFIC3, it is reduced biliary phospholipid secretion. The main clinical presentation is in the form of cholestatic jaundice and pruritus. Serum gamma glutamyl transpeptidase (GGT) is normal in patients with PFIC1/2 while it is raised in patients with PFIC3. Treatment includes nutritional support (adequate calories, supplementation of fat soluble vitamins and medium chain triglycerides) and use of medications to relieve pruritus as initial therapy followed by biliary diversion procedures in selected patients. Ultimately liver transplantation is needed in most patients as they develop progressive liver fibrosis, cirrhosis and end stage liver disease. Due to the high risk of developing liver tumors in PFIC2 patients, monitoring is recommended from infancy. Mutation targeted pharmacotherapy, gene therapy and hepatocyte transplantation are being explored as future therapeutic options.

Laparoscopic cholecystocolostomy: a novel surgical approach for the treatment of progressive familial intrahepatic cholestasis

OBJECTIVE

Conventionally, liver transplantation, ileoileal bypass, and partial external or internal biliary diversion are used in the treatment of progressive familial intrahepatic cholestasis (PFIC). However, postoperative recurrence, chronic diarrhea, and permanent stoma are the major concerns. We present a novel approach of laparoscopic cholecystocolostomy with antireflux Y-loop for the management of children with PFIC.

METHODS

Between August 2003 and April 2011, 20 children with PFIC (median age: 1.47 years; range: 10.8 months to 5.11 years) successfully underwent laparoscopic cholecystocolostomies for bile diversions. Gallbladder was incised longitudinally for cholecystocolostomy. Transverse colon was divided proximal to splenic flexure. End-to-side anastomosis was established between distal transverse colon and mid-descending colon. The mobilized splenic flexure and proximal descending colon, that is, the stem of the Y-loop, was anastomosed to the gallbladder.

RESULTS

The mean operative time was 2.02 ± 0.18 hours (range: 2-2.5 hours). The mean postoperative hospital stay was 8 days (range: 5-10 days). Average time for full resumption of diet was 3 days (range: 2-4 days). Average Y-loop length was 17.65 cm (range: 15-20 cm). The median follow-up period was 54 months (range: 12-104 months). All patients were jaundice free after 7 to 20 days and pruritus subsided in 3 to 14 days. Liver function parameters significantly improved postoperatively. Success rate (normalization of serum bile acids at postoperative 12 months) was 85%. No mortality or morbidities associated with diarrhea, cholangitis, or intrahepatic reflux were observed.

CONCLUSIONS

The novel approach of laparoscopic cholecystocolostomy offers a safe and effective treatment option for PFIC in children with good success rates and minimal morbidity.