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

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.

EASL Clinical Practice Guidelines on genetic cholestatic liver diseases

Genetic cholestatic liver diseases are caused by (often rare) mutations in a multitude of different genes. While these diseases differ in pathobiology, clinical presentation and prognosis, they do have several commonalities due to their cholestatic nature. These Clinical Practice Guidelines (CPGs) offer a general approach to genetic testing and management of cholestatic pruritus, while exploring diagnostic and treatment approaches for a subset of genetic cholestatic liver diseases in depth. An expert panel appointed by the European Association for the Study of the Liver has created recommendations regarding diagnosis and treatment, based on the best evidence currently available in the fields of paediatric and adult hepatology, as well as genetics. The management of these diseases generally takes place in a tertiary referral centre, in order to provide up-to-date approaches and expertise. These CPGs are intended to support hepatologists (for paediatric and adult patients), residents and other healthcare professionals involved in the management of these patients with concrete recommendations based on currently available evidence or, if not available, on expert opinion.

Opinion paper on the diagnosis and treatment of progressive familial intrahepatic cholestasis

Background & Aims

Progressive familial intrahepatic cholestasis (PFIC) relates to a group of rare, debilitating, liver disorders which typically present in early childhood, but have also been reported in adults. Without early detection and effective treatment, PFIC can result in end-stage liver disease. The aim of the paper was to put forward recommendations that promote standardisation of the management of PFIC in clinical practice.

Methods

A committee of six specialists came together to discuss the challenges faced by physicians in the management of PFIC. The committee agreed on two key areas where expert guidance is required to optimise care: (1) how to diagnose and treat patients with a clinical presentation of PFIC in the absence of clear genetic test results/whilst awaiting results, and (2) how to monitor disease progression and response to treatment. A systematic literature review was undertaken to contextualise and inform the recommendations.

Results

An algorithm was developed for the diagnosis and treatment of children with suspected PFIC. The algorithm recommends the use of licensed inhibitors of ileal bile acid transporters as the first-line treatment for patients with PFIC and suggests that genetic testing be used to confirm genotype whilst treatment is initiated in patients in whom PFIC is suspected. The authors recommend referring patients to an experienced centre, and ensuring that monitoring includes measurements of pruritus, serum bile acid levels, growth, and quality of life following diagnosis and during treatment.

Conclusions

The algorithm presented within this paper offers guidance to optimise the management of paediatric PFIC. The authors hope that these recommendations will help to standardise the management of PFIC in the absence of clear clinical guidelines.

Impact and implications

This opinion paper outlines a consistent approach to the contemporaneous diagnosis, monitoring, referral and management of children with progressive familial intrahepatic cholestasis. This should assist physicians given the recent developments in genetic diagnosis and the availability of effective drug therapy. This manuscript will also help to raise awareness of current developments and educate health planners on the place for new drug therapies in progressive familial intrahepatic cholestasis.

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.

Optimal liver transplant procedure in progressive familial intrahepatic cholestasis type 1 treated with biliary diversion or intestinal transplantation: Lessons learned from three cases treated with different approaches

BACKGROUND

Progressive familial intrahepatic cholestasis type 1 (PFIC1) is an autosomal recessive cholestatic liver disorder caused by ATP8B1 gene mutations. Although liver transplantation (LT) is indicated for progressive liver disease, postoperative complications, including severe diarrhea and graft steatohepatitis leading to graft loss, have been reported.

CASES

The first patient had jaundice, pruritus, diarrhea, and growth retardation (weight z-score: -2.5; height z-score: -3.7). She underwent LT with total internal biliary diversion (TIBD) to the colon at 2 years of age. Graft biopsy at the 7-year follow-up examination revealed microvesicular steatosis (60%). Her diarrhea improved, and her growth failure was recovering (weight z-score: -1.0; height z-score: -1.7). The second patient underwent sequential intestine-liver transplantation at 8 years of age due to end-stage liver disease (ESLD) and short bowel syndrome caused by massive bowel resection for internal hernia after partial external biliary diversion (PEBD) at 21 months of age. She developed severe pancreatitis induced by steroid-bolus therapy for rejection after transplantation. She died 1.7 years after intestinal transplantation due to an uncontrollable pancreatic abscess and acute respiratory distress syndrome. The third patient underwent PEBD at 15 months of age and received LT with TEBD at 15 years of age due to ESLD with hepatic encephalopathy. Throughout the perioperative period, she showed no abdominal symptoms, including diarrhea and pancreatitis. Graft biopsy at the 2-year follow-up examination revealed macrovesicular steatosis (60%) with inflammation.

CONCLUSIONS

The patients showed different outcomes. Effective therapeutic options to mitigate post-LT complications in patients with PFIC1 must be considered individually.

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.

Ileal Bile Acid Transporter Inhibition Reduces Post-Transplant Diarrhea and Growth Failure in FIC1 Disease—A Case Report

Familial intrahepatic cholestasis 1 (FIC1) disease is a genetic disorder characterized by hepatic and gastrointestinal disease due to ATP8B1 deficiency, often requiring liver transplantation (LT). Extrahepatic symptoms, such as diarrhea, malabsorption, and failure to thrive, do not improve and instead may be aggravated after LT. We describe a patient with FIC1 disease who underwent LT at 2 years, 8 months of age. After LT, the child developed severe refractory diarrhea and failed to thrive. The response to bile acid resins was unsatisfactory, and the parents declined our recommendation for partial external biliary diversion (PEBD). Quality of life was extremely impaired, especially due to severe diarrhea, making school attendance impossible. Attempting to reduce the total bile acids, we initiated off-label use of the ileal bile acid transporter (IBAT) inhibitor Elobixibat (Goofice^™), later converted to Odevixibat (Bylvay^™). After six months of treatment, the patient showed less stool output, increased weight and height, and improved physical energy levels. The child could now pursue higher undergraduate education. In our patient with FIC1 disease, the use of IBAT inhibitors was effective in treating chronic diarrhea and failure to thrive. This approach is novel; further investigations are needed to clarify the exact mode of action in this condition.