Byler's disease: fatal intrahepatic cholestasis

Sphingosine 1-phosphate receptor 2/adenylyl cyclase/protein kinase A pathway is involved in taurolithocholate-induced internalization of Abcc2 in rats

Taurolithocholate (TLC) is a cholestatic bile salt that induces disinsertion of the canalicular transporter Abcc2 (Mrp2, multidrug resistance-associated protein 2). This internalization is mediated by different intracellular signaling proteins such as PI3K, PKCε and MARCK but the initial receptor of TLC remains unknown. A few G protein-coupled receptors interact with bile salts in hepatocytes. Among them, sphingosine-1 phosphate receptor 2 (S1PR2) represents a potential initial receptor for TLC. The aim of this study was to evaluate the role of this receptor and its downstream effectors in the impairment of Abcc2 function induced by TLC. In vitro, S1PR2 inhibition by JTE-013 or its knockdown by small interfering RNA partially prevented the decrease in Abcc2 activity induced by TLC. Moreover, adenylyl cyclase (AC)/PKA and PI3K/Akt inhibition partially prevented TLC effect on canalicular transporter function. TLC produced PKA and Akt activation, which were blocked by JTE-013 and AC inhibitors, connecting S1PR2/AC/PKA and PI3K/Akt in a same pathway. In isolated perfused rat liver, injection of TLC triggered endocytosis of Abcc2 that was accompanied by a sustained decrease in the bile flow and the biliary excretion of the Abcc2 substrate dinitrophenyl-glutathione until the end of the perfusion period. S1PR2 or AC inhibition did not prevent the initial decay, but they accelerated the recovery of these parameters and the reinsertion of Abcc2 into the canalicular membrane. In conclusion, S1PR2 and the subsequent activation of AC, PKA, PI3K and Akt is partially responsible for the cholestatic effects of TLC through sustained internalization of Abcc2.

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).

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.

Byler disease: early natural history

OBJECTIVES

Byler disease, originally described in Amish kindred, results from mutations in ATPase Class I Type 8b Member 1 (ATP8b1). Specific clinical reports of Amish Byler disease were last published 40 years ago. These investigations were directed at the present detailed clinical understanding of the early course of hepatic manifestations of Byler disease.

METHODS

This study analyzed routine clinical practice and outcomes of children with Byler disease (defined by homozygous c.923G>T mutation in ATP8b1), who initially presented to Children's Hospital of Pittsburgh of UPMC between January 2007 and October 2014. Data were analyzed to the earlier of 24 months of age or partial external biliary diversion.

RESULTS

Six children presented between 1 and 135 days of life: 2 presented with newborn direct hyperbilirubinemia, 2 had complications of coagulopathy, 1 had failure to thrive and rickets, and 1 sibling was identified by newborn genetic testing. Intensive fat-soluble vitamin supplementation was required to prevent insufficiencies in vitamins D, E, and K. Hyperbilirubinemia was variable both over time and between children. Serum bile acid levels were elevated, whereas γ-glutamyltranspeptidase levels were low normal. Scratching behavior (pruritus) was intractable in 4 of 6 children with onset between 6 and 12 months of age. Features of portal hypertension were not observed. Partial external biliary diversion was used during the second year of life in 4 children.

CONCLUSIONS

Detailed analysis of Byler disease revealed varied disease presentation and course. Nutritional issues and pruritus dominated the clinical picture in the first 2 years of life.

Sandwich-cultured rat hepatocytes as an in vitro model to study canalicular transport alterations in cholestasis

At present, it has not been systematically evaluated whether the functional alterations induced by cholestatic compounds in canalicular transporters involved in bile formation can be reproduced in sandwich-cultured rat hepatocytes (SCRHs). Here, we focused on two clinically relevant cholestatic agents, such as estradiol 17β-D-glucuronide (E17G) and taurolithocholate (TLC), also testing the ability of dibutyryl cyclic AMP (DBcAMP) to prevent their effects. SCRHs were incubated with E17G (200 µM) or TLC (2.5 µM) for 30 min, with or without pre-incubation with DBcAMP (10 µM) for 15 min. Then, the increase in glutathione methyl fluorescein (GS-MF)-associated fluorescence inside the canaliculi was monitored by quantitative time-lapse imaging, and Mrp2 transport activity was calculated by measuring the slope of the time-course fluorescence curves during the initial linear phase, which was considered to be the Mrp2-mediated initial transport rate (ITR). E17G and TLC impaired canalicular bile formation, as evidenced by a decrease in both the bile canaliculus volume and the bile canaliculus width, estimated from 3D and 2D confocal images, respectively. These compounds decreased ITR and induced retrieval of Mrp2, a main pathomechanism involved in their cholestatic effects. Finally, DBcAMP prevented these effects, and its well-known choleretic effect was evident from the increase in the canalicular volume/width values; this choleretic effect is associated in part with its capability to increase Mrp2 activity, evidenced here by the increase in ITR of GS-MF. Our study supports the use of SCRHs as an in vitro model useful to quantify canalicular transport function under conditions of cholestasis and choleresis.

Liver biopsy in modern clinical practice: a pediatric point-of-view

Liver biopsy remains the foundation of evaluation and management of liver disease in children, although the role of the liver biopsy is changing with development of alternative methods of diagnosis and advancement of hepatic imaging techniques. The indications for liver biopsy are evolving as current knowledge of etiologies, noninvasive biomarker alternatives, and treatment options in pediatric liver disease are expanding. The procedure can often be complicated in children by technical difficulties, cost, and smaller specimen size. Communication and partnership of clinicians with pathologists experienced in pediatric liver diseases are essential. DNA sequencing, novel imaging modalities, noninvasive biomarkers of fibrosis and apoptosis, proteomics, and genome-wide association studies offer potential alternative methods for evaluation of liver disease in children. This review presents specific indications, considerations, methods, complications, contraindications, and alternatives for pediatric liver biopsy.

Strain background modifies phenotypes in the ATP8B1-deficient mouse

Background

Mutations in ATP8B1 (FIC1) underlie cases of cholestatic disease, ranging from chronic and progressive (progressive familial intrahepatic cholestasis) to intermittent (benign recurrent intrahepatic cholestasis). The ATP8B1-deficient mouse serves as an animal model of human ATP8B1 deficiency.

Methodology/Principal Findings

We investigated the effect of genetic background on phenotypes of ATP8B1-deficient and wild-type mice, using C57Bl/6 (B6), 129, and (B6-129) F1 strain backgrounds. B6 background resulted in greater abnormalities in ATP8B1-deficient mice than did 129 and/or F1 background. ATP8B1-deficient pups of B6 background gained less weight. In adult ATP8B1-deficient mice at baseline, those of B6 background had lower serum cholesterol levels, higher serum alkaline phosphatase levels, and larger livers. After challenge with cholate-supplemented diet, these mice exhibited higher serum alkaline phosphatase and bilirubin levels, greater weight loss and larger livers. ATP8B1-deficient phenotypes in mice of F1 and 129 backgrounds are usually similar, suggesting that susceptibility to manifestations of ATP8B1 deficiency may be recessive. We also detected differences in hepatobiliary phenotypes between wild-type mice of differing strains.

Conclusions/Significance

Our results indicate that the ATP8B1-deficient mouse in a B6 background may be a better model of human ATP8B1 deficiency and highlight the importance of informed background strain selection for mouse models of liver disease.

Nontransplant surgical interventions in progressive familial intrahepatic cholestasis

BACKGROUND

Progressive familial intrahepatic cholestasis (PFIC) is a family of rare childhood diseases that was universally fatal until the development of liver transplant. In the last 20 years, the use of nontransplant surgery to treat PFIC has become the standard of care. There are various surgical techniques that have been performed. There are no reviews evaluating the outcome of these operations.

METHODS

A systematic search of the literature for articles evaluating the outcome of nontransplant surgical interventions in PFIC patients was performed. Data from these studies was abstracted and summarized.

RESULTS

No trials have been performed addressing nontransplant surgical interventions in PFIC patients. We analyzed 11 case series and case reports. Generally, patients had successful outcomes (81%) with cessation of progression of disease and resolution of symptoms. Treatment failures were often associated with more advanced disease.

DISCUSSION

There is no evidence to demonstrate a superiority of one type of nontransplant surgical intervention in PFIC patients. We propose the development of a registry and standardization of outcomes measurements to allow improved comparison of results.

Fic1 is expressed at apical membranes of different epithelial cells in the digestive tract and is induced in the small intestine during postnatal development of mice

Mutations in ATP8B1 are associated with FIC1 disease, an autosomal recessive disorder in which intrahepatic cholestasis is the predominant manifestation. ATP8B1 encodes FIC1, which is expressed in several tissues, most prominently in the intestine, pancreas, and stomach and, to a much lesser extent, in the liver. In this study, Fic1 localization and expression during postnatal development was examined in healthy mice. Immunoblot and RT-PCR analysis indicated Fic1 is expressed abundantly in regions of the adult gastrointestinal tract of humans and mice. Immunohistochemistry revealed that Fic1 was localized to the apical membranes of enterocytes, pancreatic acinar cells, gastric pit epithelial cells, and hepatocytes and cholangiocytes. Subsequent analysis of early postnatal expression revealed that Fic1 expression in the small intestine was limited or absent at the age of 7 and 14 d and increased significantly with maturation. In contrast, pancreatic, hepatic, and gastric Fic1 expression was not diminished during the first 3 wk of postnatal development. In conclusion, these data show that Fic1 is expressed in a tissue-specific and developmentally regulated fashion at the apical membranes of epithelial cells. We speculate that the developing bile salt pool in the maturing intestine accounts for the increase in Fic1 protein expression in this tissue.

Reduced hepatic expression of farnesoid X receptor in hereditary cholestasis associated to mutation in ATP8B1

Farnesoid X receptor (FXR) is a transcription factor that controls bile acid homeostasis. The phenotype of Fxr null mice is characterized by hypercholanaemia, impaired secretion of bile acids and failure to thrive. Human disorders with these characteristics include FIC1 disease (caused by mutations in ATP8B1, which encodes a putative aminophospholipid translocase, FIC1, whose function in bile handling is unknown) and bile salt export pump (BSEP) disease (caused by mutation in ABCB11, which encodes BSEP, the primary canalicular bile salt export pump). We investigated the possibility of hepatic down-regulation of FXR in FIC1 disease and BSEP disease. Three siblings with this phenotype, born to consanguine parents, were initially studied. The children were demonstrated to be compound heterozygotes for missense and nonsense mutations in ATP8B1. Expression of specific genes in liver was analysed, comparing one of these siblings with a child homozygous for missense mutation in ABCB11, as well as with a child having idiopathic cholestatic liver disease, a child with extrahepatic biliary atresia and a normal organ donor. The expression of two main FXR isoforms was specifically decreased in the liver of the FIC1 disease patient. A consistent and concomitant reduction in messenger RNA levels of FXR targets, such as BSEP and small heterodimer partner, was also found. Gene-profiling experiments identified 163 transcripts whose expression changed significantly in FIC1-disease liver. Of note was that several genes involved in synthesis, conjugation and transport of bile acids were down-regulated. A cluster of genes involved in lipid metabolism was also differentially expressed. Our findings suggest that hepatic down-regulation of FXR contributes to the severe cholestasis of FIC1 disease.

Characterization of mutations in ATP8B1 associated with hereditary cholestasis

Progressive familial intrahepatic cholestasis (PFIC) and benign recurrent intrahepatic cholestasis (BRIC) are clinically distinct hereditary disorders. PFIC patients suffer from chronic cholestasis and develop liver fibrosis. BRIC patients experience intermittent attacks of cholestasis that resolve spontaneously. Mutations in ATP8B1 (previously FIC1) may result in PFIC or BRIC. We report the genomic organization of ATP8B1 and mutation analyses of 180 families with PFIC or BRIC that identified 54 distinct disease mutations, including 10 mutations predicted to disrupt splicing, 6 nonsense mutations, 11 small insertion or deletion mutations predicted to induce frameshifts, 1 large genomic deletion, 2 small inframe deletions, and 24 missense mutations. Most mutations are rare, occurring in 1-3 families, or are limited to specific populations. Many patients are compound heterozygous for 2 mutations. Mutation type or location correlates overall with clinical severity: missense mutations are more common in BRIC (58% vs. 38% in PFIC), while nonsense, frameshifting, and large deletion mutations are more common in PFIC (41% vs. 16% in BRIC). Some mutations, however, lead to a wide range of phenotypes, from PFIC to BRIC or even no clinical disease. ATP8B1 mutations were detected in 30% and 41%, respectively, of the PFIC and BRIC patients screened.

Progressive familial intrahepatic cholestasis, type 1, is associated with decreased farnesoid X receptor activity

BACKGROUND & AIMS

The mechanisms by which mutations in the familial intrahepatic cholestasis-1 gene cause Byler's disease (progressive familial intrahepatic cholestasis type 1) are unknown.

METHODS

Interactions among the apical sodium-dependent bile acid transporter, the farnesoid X receptor (FXR), and familial intrahepatic cholestasis-1 were studied in the ileum of children with progressive familial intrahepatic cholestasis type 1 and in Caco-2 cells.

RESULTS

Increased ileal apical sodium-dependent bile acid transporter messenger RNA (mRNA) expression was detected in 3 patients with progressive familial intrahepatic cholestasis type 1. Paradoxically, ileal lipid-binding protein mRNA expression was repressed, suggesting a central defect in bile acid response. Ileal FXR and short heterodimer partner mRNA levels were reduced in the same 3 patients. In Caco-2 cells, antisense-mediated knock-down of endogenous familial intrahepatic cholestasis-1 led to up-regulation of apical sodium-dependent bile acid transporter and down-regulation of FXR, ileal lipid-binding protein, and short heterodimer partner mRNA. In familial intrahepatic cholestasis-1-negative Caco-2 cells, the activity of the human apical sodium-dependent bile acid transporter promoter was enhanced, whereas the human FXR and bile salt excretory pump promoters' activities were reduced. Overexpression of short heterodimer partner but not of the FXR abrogated the effect of familial intrahepatic cholestasis-1 antisense oligonucleotides. FXR cis-element binding and FXR protein were reduced primarily in nuclear but not cytoplasmic extracts from familial intrahepatic cholestasis-1-negative Caco-2 cells.

CONCLUSIONS

Loss of familial intrahepatic cholestasis-1 leads to diminished nuclear translocation of the FXR, with the subsequent potential for pathologic alterations in intestinal and hepatic bile acid transporter expression. Marked hypercholanemia and cholestasis are predicted to develop, presumably because of both enhanced ileal uptake of bile salts via up-regulation of the apical sodium-dependent bile acid transporter and diminished canalicular secretion of bile salts secondary to down-regulation of the bile salt excretory pump.

Abnormalities in villin gene expression and canalicular microvillus structure in progressive cholestatic liver disease of childhood

BACKGROUND

The molecular basis of clinical cholestasis is a subject of intense investigation. Villin is an actin binding, bundling, and severing protein needed for maintenance of structural integrity of canalicular microvilli, in which membrane transporters required for bile secretion are located. We aimed to investigate the role of canalicular cytoskeletal proteins in three genetically unrelated children with a biliary atresia-like clinical disorder, each of whom developed liver failure requiring liver transplantation.

METHODS

Explanted livers from the three patients were examined by standard pathological methods followed by transmission and cryoimmunoelectron microscopy. With archival tissue samples, a panel of cytoskeletal proteins was investigated by immunohistochemistry and western blotting, with purified canalicular membrane preparations. Villin mRNA analyses were undertaken on liver homogenates, with primers from coding regions of the human villin gene. Classic biliary atresia, other types of cholestasis, and normal livers served as controls.

FINDINGS

In patients, pronounced ultrastructural deformities of canaliculi and especially of their microvilli were noted, which correlated with absence of villin protein by immunostaining of liver tissue sections and by western blot analysis. Additionally, villin mRNA was strikingly reduced or absent. These results differed greatly from those in controls.

INTERPRETATION

These results suggest that the disorder described mimics biliary atresia, but structural and molecular pathological findings differ. We propose that a functional abnormality in villin gene expression is key to the mechanism of cholestasis in patients with progressive cholestasis and hepatic failure.

Disorders of bile formation and biliary transport

A wide range of cholestatic liver diseases result from various primary defects in bile formation. Clinical features include jaundice, pruritus, failure to thrive, fat malabsorption, cholelithiasis, and variably progressive cirrhosis. Accurate diagnosis of these disorders is essential for determination of prognosis and selection of the most appropriate therapies. Severe genetic defects in canalicular bile acid and phospholipid excretion lead to progressive liver disease that often requires liver transplantation. Defects in bile acid biosynthesis and aminophospholipid transport may be responsive to medical or non-transplant surgical approaches.

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

BACKGROUND/AIMS

Progressive familial intrahepatic cholestasis characterized by normal serum gamma-glutamyltransferase activity can be due to mutations in familial intrahepatic cholestasis type 1 (FIC1) (ATP8B1), a gene expressed in several organs. In some cases, it is associated with extrahepatic features. We searched for FIC1 mutations and analyzed the outcome of extrahepatic features after liver transplantation in two children with this form of progressive familial intrahepatic cholestasis associated with chronic unexplained diarrhea and short stature.

METHODS

FIC1 sequence was determined after polymerase chain reaction (PCR) of genomic lymphocyte DNA and/or reverse transcription-PCR of liver or lymphocyte RNA.

RESULTS

A homozygous amino acid change deletion was found in one child. The second child harboured compound heterozygous missense and nonsense mutations. In both children, despite successful liver transplantation, evolution (follow-up: 9.5-11 years) was characterized by exacerbation of diarrhea and no catch-up of stature growth, and appearance of liver steatosis.

CONCLUSIONS

Progressive familial intrahepatic cholestasis characterized by normal serum gamma-glutamyltransferase activity and extrahepatic features corresponds to progressive familial intrahepatic cholestasis type 1. Extrahepatic symptomatology is not corrected or may be aggravated by liver transplantation, impairing life quality.

Preventive effect of silymarin against taurolithocholate-induced cholestasis in the rat

Increased amounts of monohydroxylated bile salts (BS) have been found in neonatal cholestasis, parenteral nutrition-induced cholestasis and Byler's disease, among others. We analyzed whether the hepatoprotector silymarin (SIL), administered i.p. at the dose of 100mg/kg/day for 5 days, prevents the cholestatic effect induced by a single injection of the model monohydroxylated BS taurolithocholate (TLC, 30 micromol/kg, i.v.) in male Wistar rats. TLC, administered alone, reduced bile flow, total BS output, and biliary output of glutathione and HCO(3)(-) during the peak of cholestasis (-75, -67, -81, and -80%, respectively, P<0.05). SIL prevented partially these alterations, so that the drops of these parameters induced by TLC were of only -41, -25, -60, and -64%, respectively (P<0.05 vs. TLC alone); these differences between control and SIL-treated animals were maintained throughout the whole (120 min) experimental period. Pharmacokinetic studies showed that TLC decreased the intrinsic fractional constant rate for the canalicular transport of both sulfobromophthalein and the radioactive BS [14C]taurocholate by 60 and 68%, respectively (P<0.05), and these decreases were fully and partially prevented by SIL, respectively. SIL increased the hepatic capability to clear out exogenously administered TLC by improving its own biliary excretion (+104%, P<0.01), and by accelerating the formation of its non-cholestatic metabolite, tauromurideoxycholate (+70%, P<0.05). We conclude that SIL counteracts TLC-induced cholestasis by preventing the impairment in both the BS-dependent and -independent fractions of the bile flow. The possible mechanism/s involved in this beneficial effect will be discussed.

Genetic defects in hepatobiliary transport

Bile formation, the exocrine function of the liver, represents a process that is unique to the hepatocyte as a polarized epithelial cell. The generation of bile flow is an osmotic process and largely depends on solute secretion by primary active transporters in the apical membrane of the hepatocyte. In recent years an impressive progress has been made in the discovery of these proteins, most of which belong to the family of ABC transporters. The number of identified ABC transporter genes has been exponentially increasing and the mammalian subfamily now counts at least 52. This development has been of crucial importance for the elucidation of the mechanism of bile formation, and it is therefore not surprising that the development in this field has run in parallel with the discovery of the ABC genes. With the identification of these transporter genes, the background of a number of inherited diseases, which are caused by mutations in these solute pumps, has now been elucidated. We now know that at least six primary active transporters are involved in canalicular secretion of biliary components (MDR1, MDR3, BSEP, MRP2, BCRP and FIC1). Four of these transporter genes are associated with inherited diseases. In this minireview we will shortly describe our present understanding of bile formation and the associated inherited defects.

Benign recurrent intrahepatic cholestasis progressing to progressive familial intrahepatic cholestasis: low GGT cholestasis is a clinical continuum

Benign recurrent intrahepatic cholestasis (BRIC) is an autosomal recessive liver disease, characterised by intermittent attacks of cholestasis, which can start at any age and last for several weeks to months. Characteristically serum GGT activity is low and normal liver structure is preserved. Progressive familial intrahepatic cholestasis (PFIC) is another liver disease, characterised by severe cholestasis, starting almost invariably before 6 months of age. All patients progress to cirrhosis, liver failure and death, unless a liver transplantation is performed. We now identified four patients who presented in childhood with recurrent attacks of cholestasis, while in the course of the disease the cholestasis gradually became permanent. Although liver biopsies performed in the early stages of the disease showed normal liver architecture, late stage biopsies revealed evident fibrosis with porto-portal septa formation. In conclusion, the disease of these patients started with the clinical and histopathological characteristics of BRIC but progressed to PFIC.

FIC1, the protein affected in two forms of hereditary cholestasis, is localized in the cholangiocyte and the canalicular membrane of the hepatocyte

BACKGROUND/AIMS

FIC1 (familial intrahepatic cholestasis 1) is affected in two clinically distinct forms of hereditary cholestasis, namely progressive familial intrahepatic cholestasis type 1 (PFIC1) and benign recurrent intrahepatic cholestasis. Here we examined the subcellular localization of this protein within the liver.

METHODS

Antibodies raised against different epitopes of human FIC1 were used for immunoblot analysis and immunohistochemical detection of FICI.

RESULTS

Immunoblot analysis of intestine and liver tissue extracts from human, rat and mouse origin indicated that the antibodies raised against FIC1 specifically detected FIC1 as a 140-kDa protein. In the liver homogenate of a PFIC1 patient, FIC1 could not be detected. Analysis of isolated rat liver membrane vesicles indicated that this protein is predominantly present in the canalicular membrane fraction. Immunohistochemical detection of the protein in liver sections confirmed that FIC1 was present in the canalicular membrane, whereas no staining was observed in the PFIC1 patients liver. Double label immunofluorescence of murine liver revealed that FIC1 colocalized with cytokeratin 7 in cholangiocytes.

CONCLUSIONS

The localization of FIC1 in the canalicular membrane and cholangiocytes suggests that it may directly or indirectly play a role in bile formation since mutations in FICI are associated with severe symptoms of cholestasis.

The wide spectrum of multidrug resistance 3 deficiency: from neonatal cholestasis to cirrhosis of adulthood

BACKGROUND & AIMS

We have specified the features of progressive familial intrahepatic cholestasis type 3 and investigated in 31 patients whether a defect of the multidrug resistance 3 gene (MDR3) underlies this phenotype.

METHODS

MDR3 sequencing, liver MDR3 immunohistochemistry, and biliary phospholipid dosage were performed.

RESULTS

Liver histology showed a pattern of biliary cirrhosis with patency of the biliary tree. Age at presentation ranged from the neonatal period to early adulthood. Sequence analysis revealed 16 different mutations in 17 patients. Mutations were identified on both alleles in 12 patients and only on 1 allele in 5. Four mutations lead to a frame shift, 2 are nonsense, and 10 are missense. An additional missense mutation probably representing a polymorphism was found in 5 patients. MDR3 mutations were associated with abnormal MDR3 canalicular staining and a low proportion of biliary phospholipids. Gallstones or episodes of cholestasis of pregnancy were found in patients or parents. Children with missense mutations had a less severe disease and more often a beneficial effect of ursodeoxycholic acid therapy.

CONCLUSIONS

At least one third of the patients with a progressive familial intrahepatic cholestasis type 3 phenotype have a proven defect of MDR3. This gene defect should also be considered in adult liver diseases.

Progressive familial intrahepatic cholestasis. Genetic basis and treatment

Major advances in the understanding of the molecular mechanisms of bile formation and genetic studies of children with chronic cholestasis uncovered the molecular basis of PFIC. Specific defects in the FIC1, BSEP, and MDR3 genes are responsible for distinct PFIC phenotypes. These findings have confirmed the autosomal recessive inheritance of the disease and now provide specific diagnostic tools for the investigation of children with PFIC. This understanding should also allow prenatal diagnosis in the future. Identification of mutations in these genes will allow genotype-phenotype correlations to be defined within the spectrum of PFIC. These correlations performed in patients previously treated by UDCA or biliary diversion should identify those PFIC patients who could benefit from these therapies. In the future, other therapies, such as cell and gene therapies, might represent an alternative to liver transplantation. It remains to be determined if defects in the FIC1, BSEP, and MDR3 genes are responsible for all types of PFIC, or if other yet undiscovered genes, possibly involved in bile formation or its regulation, may be involved in the pathogenesis of PFIC.

North American Indian cirrhosis in children: a review of 30 cases

BACKGROUND

North American Indian childhood cirrhosis (NAIC) is a distinct, rapidly evolving form of familial cholestasis found in aboriginal children from northwestern Quebec. This is a retrospective review of the 30 patients treated in Quebec since the discovery of NAIC in 1970.

METHODS

The clinical records and histologic samples from 30 patients were reviewed. Extensive metabolic, biochemical, viral, genetic, and radiologic studies were performed in most patients.

RESULTS

Genetic analysis suggests autosomal recessive inheritance and a carrier frequency of 10% in this population. Gene mapping studies showed that the NAIC gene is located on chromosome 16q22. Typically, patients have neonatal cholestatic jaundice (70%) or hepatosplenomegaly (20%) with resolution of clinical jaundice by age 1 year but persistent direct hyperbilirubinemia. Portal hypertension was documented in 29 patients (91%). Variceal bleeding (15 patients, 50%) occurred as early as age 10 months. Surgical portosystemic shunting was performed in 13 of these 15 patients (87%); 4 (31%) rebled after 1 to 5 years. Fourteen patients died (47%). In 10 (71%), liver disease was the cause. Four children died of liver failure before liver transplantation became available. In transplanted livers, no recurrence of NAIC was observed after 1 to 10 years. Recognized infectious, metabolic, toxic, autoimmune, and obstructive causes of cirrhosis have been eliminated. The histologic features of NAIC show early bile duct proliferation and rapid development of portal fibrosis and biliary cirrhosis, suggesting a cholangiopathic phenomenon.

CONCLUSION

Together with gene mapping studies showing that the NAIC gene is different from those of other familial cholestases, these observations suggest that NAIC is a distinct entity that could be classified as "progressive familial cholangiopathy."

Role of perivenous hepatocytes in taurolithocholate-induced cholestasis in vivo

The magnitude of cholestasis induced by taurolithocholic acid (TLCA) and its relationship with phase I metabolism were analyzed in rats treated with bromobenzene (BZ), a chemical that causes selective necrosis of perivenous (zone 3) hepatocytes. Forty-eight hours after BZ administration (600 mg/Kg bw), a single dose of 20 micromol/Kg bw of TLCA was injected. Bile was collected during 180 min and bile flow and total bile acid excretion rate were determined. Biliary bile acid composition was analyzed by gas-liquid chromatography-mass spectrometry. BZ administration did not affect the development of TLCA-induced cholestasis, but exacerbated the bile acid-induced decrease in bile flow during the period of recovery from cholestasis. Biliary excretion of total bile acids after TLCA injection relative to basal value was not effected by BZ. The analysis of bile acid composition in bile revealed that TLCA was partially converted to hyodeoxycholic and muricholic acids. The cumulative excretion of all exogenous bile acids and their contribution to the composition of the biliary bile acid pool were not substantially affected by zone 3 necrosis, suggesting that synthesis and secretion of hydroxylated derivatives of TLCA were maintained by zone 1 and 2 hepatocytes. The relative content of endogenous bile acids was not affected by BZ during TLCA-induced cholestasis. Thus, it seems unlikely that the exacerbation of the cholestasis in BZ-treated rats is due to different choleretic properties and/or toxicity of the bile acid pool.

Abnormal hepatic sinusoidal bile acid transport in an Amish kindred is not linked to FIC1 and is improved by ursodiol

BACKGROUND & AIMS

The mechanism for abnormal hepatic bile acid transport was investigated in an 18-month-old Amish boy who presented with pruritus, poor growth, and severe bleeding episodes. Serum bilirubin, gamma-glutamyltranspeptidase, and cholesterol levels were normal, but prothrombin time and partial thromboplastin time were prolonged and bone alkaline phosphatase level was elevated.

METHODS AND RESULTS

Cholic acid plus chenodeoxycholic acid levels measured by capillary gas-chromatography were 32 times higher than control in serum (34.7 vs. 1.1+/-0.4 microg/dL) but were not detected in liver and were reduced in gallbladder bile. Treatment with ursodiol, a more hydrophilic bile acid, improved pruritus, produced 37% weight gain, and after 2 years reduced serum primary bile acid concentrations about 85%, while accounting for 71% of serum and 24% of biliary bile acid conjugates. On ursodiol therapy, hepatic bile acid synthesis was enhanced 2-fold compared with controls, and microscopy revealed chronic hepatitis without cholestasis. Three younger sisters with elevated serum bile acids responded positively to ursodiol. Microsatellite markers for the FIC1 (gene for Byler's disease) region in these 4 children were inconsistent with linkage to FIC1.

CONCLUSIONS

Conjugated cholic acid and chenodeoxycholic acid were synthesized in the liver and secreted into bile but could not reenter the liver from portal blood and accumulated in serum. In contrast, unconjugated ursodiol entered the liver and was conjugated and secreted into bile. Thus, the enterohepatic circulation of all conjugated bile acids was interrupted at the hepatic sinusoidal basolateral membrane. Unconjugated ursodiol bypassed the hepatic uptake block to enlarge the biliary and intestinal bile acid pools. A mutation in FIC1 recognized among the Amish and linkage of the disorder to FIC1 were excluded.

Bile acid abnormalities in cholestatic liver diseases

There is ample reason to believe that UDCA is the drug of choice in cholestatic liver diseases. It is possible that UDCA has to be administered for prolonged periods to see appreciable reversal in liver damage. Nevertheless, the amelioration of symptoms and improvement in nutrition of patients are equally important. Disabling symptoms such as pruritus are often brought under control, and quality of life improves. Clearly the goal for UDCA therapy is to slow the rate of disease progression, lessen the mortality risk, and improve the quality of life in patients. It is possible that a combination therapy would be more beneficial than UDCA alone. Initial results of administering UDCA with colchicine have shown no improvement in liver histology; however, administration of UDCA together with a strong anti-inflammatory drugs may be helpful to halt immune destruction of liver cells.

Sensorineural hearing loss associated with Byler disease

Progressive familial intrahepatic cholestasis, sometimes described as Byler disease, is a lethal liver disease and its inheritance is autosomal recessive. There is a previous report on the occasional association between this disease and sensorineural hearing loss without any audiological findings. We report here two siblings, an 18-year-old female and a 16-year-old male, suffering from Byler disease and hearing loss. Pure tone, Bekesy and speech audiometries and auditory brain stem response examination were performed. Audiometric data showed hearing characteristics of cochlear origin, high-frequency loss and progressiveness. This sensorineural hearing loss possibly results from a genetic mutation. The mechanism of cochlear disorder in patients with Byler disease is unknown, however, a novel gene responsible for deafness might be found to be related to Byler disease.

A gene encoding a P-type ATPase mutated in two forms of hereditary cholestasis

Cholestasis, or impaired bile flow, is an important but poorly understood manifestation of liver disease. Two clinically distinct forms of inherited cholestasis, benign recurrent intrahepatic cholestasis (BRIC) and progressive familial intrahepatic cholestasis type 1 (PFIC1), were previously mapped to 18q21. Haplotype analysis narrowed the candidate region for both diseases to the same interval of less than 1 cM, in which we identified a gene mutated in BRIC and PFIC1 patients. This gene (called FIC1) is the first identified human member of a recently described subfamily of P-type ATPases; ATP-dependent aminophospholipid transport is the previously described function of members of this subfamily. FIC1 is expressed in several epithelial tissues and, surprisingly, more strongly in small intestine than in liver. Its protein product is likely to play an essential role in enterohepatic circulation of bile acids; further characterization of FIC1 will facilitate understanding of normal bile formation and cholestasis.

Ileal exclusion for Byler's disease: an alternative surgical approach with promising early results for pruritus

BACKGROUND/PURPOSE

Progressive familial intrahepatic cholestasis (Byler's disease) is often characterized by pruritus-induced self-mutilation with minimal response to medical therapy. The causative cholestasis is likely to progress to cirrhosis necessitating transplantation. Partial external biliary diversion has been used with promising results for the jaundice and debilitating pruritus but all the potential complications and aesthetic concerns of long-term stomas attend this approach.

METHODS

The authors describe a terminal ileal exclusion that was first developed for patients who had previously undergone cholecystectomy. Over a 3-year period, we identified for study seven children with liver histology characteristic of Byler's disease accompanying a clinical picture of chronic cholestasis without a defined metabolic or anatomic abnormality. The first two patients underwent a cholecystojejunal cutaneous stoma, until now, the recommended treatment for this condition. The third had previously undergone cholecystectomy so an ileocolonic anastomosis was performed excluding the distal 15% of the small bowel. This child had complete relief of pruritus without evidence of diarrhea. Two more terminal ileal exclusions were performed with similar results before standardizing this approach. The authors approximated small intestinal length using Siebert's graph relating crown-heel length to small intestinal length. The midpoint between the mean and one standard deviation below the mean was determined. Fifteen percent of the estimated small bowel length was measured back from the ileocecal valve and then divided using a linear stapling device. A stapled anastomosis was created between the proximal ileum and the cecum, bypassing the terminal ileum.

RESULTS

Four of five children have had relief from their pruritus and self-mutilation with no evidence of diarrhea. Terminal ileal bypass offers a stoma-free, completely reversible "biliary diversion."

CONCLUSION

Early results on a few patients are promising, but long-term evaluation of growth, development, and liver function and histology is needed before advocating this as the primary therapy for Byler's disease.

[Progressive familial intrahepatic cholestasis and hereditary anomalies lf hepatocellular metabolism of bile acids]

Progressive familial intrahepatic cholestasis (PFIC), also known as Byler disease, is an inherited cholestasis of hepatocellular origin which is characterized by cholestasis presenting often in the neonatal period leading to death due to liver failure at ages ranging from infancy to adolescence. The pattern of appearance of affected children within families is consistent with autosomal recessive inheritance. The etiology is poorly understood but several studies have recently provided support for an heterogeneity with at least three subcategories among the spectrum of PFIC. The first subtype is characterized by an early onset, often during the neonatal period, a severe pruritus, normal serum gamma-glutamyltransferase (GGT) activity and cholesterol level, high concentration of serum primary bile acids, absence or very low levels of primary bile acids, absence or very low levels of primary bile acids in bile, and absence of ductular proliferation on standard optical liver histology. Its leads to death due to liver failure within a few years, rarely after adolescence. It is possibly due to an inborn error in primary bile acid secretion and recently, a locus for this subtype has been mapped in the original Byler pedigree to 18q21-q22, the benign recurrent intrahepatic cholestasis region. In the second subtype, affected children exhibit also normal serum GGT activity and cholesterol level and absence of ductular proliferation, but have no pruritus and only traces of primary bile acids in serum. An inborn error in primary bile acid synthesis has been demonstrated in this subtype. The third subtype presents later in life, carries a higher risk of portal hypertension and gastrointestinal bleeding and ends in liver failure at a later age. It is characterized by a mild and unconstant pruritus, high GGT serum activity, moderately raised concentrations of serum primary bile acids, normal concentration of biliary primary bile acids, and ductular proliferation and inflammatory infiltrate with patency of intra and extrahepatic bile ducts. An abnormal expression of the MDR3 gene is involved. A fair proportion of children affected with all subtypes of PFIC may benefit from oral bile acid therapy. In some cases partial external biliary diversion or liver transplantation should be proposed.

Progressive familial intrahepatic cholestasis among the Arab population in Israel

BACKGROUND

Progressive familial intrahepatic cholestasis, which constitutes a heterogeneous group of imperfectly delineated syndromes and appears to be inherited as an autosomal recessive condition, has not been hitherto reported from the Middle East, in spite of the high rate of consanguineous marriage in this region.

METHODS

Sixteen affected children from six Israeli Arab families were evaluated over 30 years. All were born to consanguineous parents.

RESULTS

Jaundice appeared during the first 3 weeks of life in 15 babies. When first referred, 10 had hepatomegaly and nine had splenomegaly. A progression toward cirrhosis was the rule. Serum levels of conjugated bilirubin, liver enzymes, and alkaline phosphatase were raised; gamma-glutamyl transpeptidase levels were normal in all three infants in whom it was examined, but elevated in two siblings of another family at ages 2 and 3 years. No abnormal bile acids were detected in the serum and urine of patients. Histologic examination of the liver showed giant-cell transformation, paucity of intrahepatic bile ducts, cholestasis, fibrosis, or cirrhosis. The pattern of liver pathology differed at times among affected members within the same family. Therapeutic trials with phenobarbital, cholestyramine, or ursodeoxycholic acid were ineffective. Survival of the patients was from 5 to 18 months in four families; in the other two families, three children received liver transplants, and one is awaiting liver transplantation.

CONCLUSIONS

Progressive familial intrahepatic cholestasis should be included in the differential diagnosis of infants with cholestatic jaundice of unknown etiology, especially those born to consanguineous Arab parents.

Byler-like familial cholestasis in an extended kindred

Progressive familial intrahepatic cholestasis (PFIC) occurs in many communities and races. A form of PFIC in five children from two consanguineous marriages in an Irish kindred is described. In addition, a review of clinical information from the records of three deceased members of the kindred strongly implies that they also suffered from PFIC. The children had a history of neonatal diarrhoea, sepsis, and intermittent jaundice that ultimately became permanent. They suffered intractable pruritus and growth retardation. Despite evidence of severe cholestasis, serum gamma-glutamyl transferase and cholesterol were normal in these children. Sweat sodium concentration were raised in three children. Liver histology showed severe intrahepatic cholestasis and hepatocellular injury. Urinary bile acid analysis revealed a non-specific pattern consistent with chronic cholestasis. These children suffer from a form of PFIC remarkably similar to that occurring in members of the Byler kindred.

Anaesthetic considerations in progressive familial intrahepatic cholestasis (Byler's disease)

Progressive familial intrahepatic cholestasis (PFIC) or Byler's disease is one of the most common forms of intrahepatic cholestasis of metabolic and genetic origin. Affected children progress to terminal cirrhosis before adulthood and at present the only curative treatment of PFIC is orthotopic liver transplantation (OLT). We present a retrospective review of 40 general anaesthetics administered in our hospital to 22 patients with PFIC undergoing various procedures. The clinical features of PFIC and the anaesthetic implications of chronic cholestasis in children (malnutrition, cirrhosis, portal hypertension, chronic hypoxaemia) are reviewed.

Selective surgical management of progressive familial intrahepatic cholestasis (Byler's disease)

Progressive familial intrahepatic cholestasis (PFIC) presents in early childhood with pruritus, jaundice, hepatomegaly, and growth failure. Medical therapy is unsuccessful, with progression from cholestasis to hepatic fibrosis, cirrhosis, and ultimately death before the age of 10 years. Because of evidence that biliary diversion can arrest or reverse progression to hepatic fibrosis, we have used partial biliary diversion (PBD) as primary therapy in PFIC, reserving orthotopic liver transplantation (OLT) for children who have progressive disease or established cirrhosis. Seventeen children with PFIC (aged 2 months to 19 years) have been treated. PBD was performed in eight cases. In these procedures, a 10-cm properistaltic jejunal segment was anastomosed to the side of the gallbladder, terminating as an end stoma for the collection and discard of bile. Eleven patients with hepatic insufficiency (or end-stage cirrhosis) received OLT using standard techniques, at the average age of 4 years. Six of the eight children treated with PBD had complete resolution of clinical symptoms and remain well 1 to 13 years postoperatively. These six patients have conjugated bilirubin values of less than 0.3 mg/dL, normal transaminases, and a serum bile salt concentration of less than 10 nmol/mL. All have had either reversal or no progression of the hepatic fibrosis. Postoperative bleeding complications occurred in two (25%), which required reoperation. One patient had an adhesive intestinal obstruction that was managed surgically 9 months postoperatively. Two patients had no benefit from PBD, and all of them had severe bridging fibrosis (1) or cirrhosis (3). These and nine others with cirrhosis at the time of presentation received orthotopic liver transplantation; of these, eight are alive (1 to 5 years postoperatively). These results show the importance of establishing a correct diagnosis in children with cholestasis. Clinical symptoms often are severe in children with PFIC before the development of irreversible hepatic fibrosis. Because several patients who appear to have been cured with PBD initially were scheduled for OLT, it is important that transplant surgeons recognize the feasibility of this approach.

A new cause of progressive intrahepatic cholestasis: 3 beta-hydroxy-C27-steroid dehydrogenase/isomerase deficiency

There have been a few reports of infants with severe neonatal cholestasis related to a defect in primary bile acid synthesis. To assess the importance of such deficiency among children with progressive intrahepatic cholestasis (Byler disease), screening for inborn errors in bile acid synthesis was performed by fast atom bombardment ionization-mass spectrometry of urine samples from 30 affected children. Bile acid analysis revealed a specific fast atom bombardment ionization-mass spectrometry profile for 3 beta-hydroxy-C27 steroid dehydrogenase/isomerase deficiency in five children who had jaundice, hepatosplenomegaly, and fatty stools beginning at ages ranging from 4 to 46 months. None of them had pruritus. Liver function tests showed persistently normal serum gamma-glutamyltransferase activity, low serum cholesterol and vitamin E levels, normal serum bile acid concentrations despite raised serum bilirubin levels, and decreased prothrombin time and clotting factor V. In four of the cases a similar disease was observed in siblings. Liver function returned to normal after oral ursodeoxycholic acid therapy. We conclude that 3 beta-hydroxy-C27-steroid dehydrogenase/isomerase deficiency should be considered when idiopathic cholestatic liver disease with clinical features akin to Byler disease is characterized by the association of normal serum gamma-glutamyltransferase activity, normal serum bile acid concentration, absence of pruritus, and a return to normal liver function during ursodeoxycholic acid therapy. Early identification of these children is essential because they benefit from bile acid therapy and might thus avoid the need for liver transplantation.

Evidence for defective primary bile acid secretion in children with progressive familial intrahepatic cholestasis (Byler disease)

To clarify the relationship of progressive familial intrahepatic cholestasis (Byler disease) to bile acid metabolism, we analysed, by high performance liquid chromatography, the bile acid composition of serum and bile in seven children with Byler disease and in eight control children with other cholestatic diseases. In serum, total bile acid concentration was increased in patients with Byler disease (0.30 +/- 0.05 mmol/l) and in control patients (0.21 +/- 0.08 mmol/l). Cholate (C) and chenodeoxycholate (CDC) comprised the major proportion of total bile acids in patients with Byler disease as in control patients. Hyocholate (HC) was only detected in patients with Byler disease and lithocholate was only present in control children. In bile, total bile acid concentration was very low in patients with Byler disease (1.1 +/- 1.4 mmol/l) compared to control patients (88.9 +/- 83.2 mmol/l). C and CDC were the major bile acids in control patients, whereas C and HC comprised the major proportion of bile acids in patients with Byler disease. These results suggest the existence of a defect of primary bile acid secretion in Byler disease characterized by the presence of high concentration of bile acids in serum and absence or very low concentration of bile acids in bile.

Hepatic transport of organic anions in taurolithocholate-induced cholestasis in rats

The hepatic transport of organic anions was evaluated in taurolithocholate-induced cholestasis in rats. Taurolithocholate (3 mumol per 100 g body wt., i.v.) diminished bile flow by 61%, whereas biliary excretion of bile salts was normalized after 80 min. Tm studies of sulfobromophthalein revealed reduced biliary excretion (-58%) and increased hepatic content of the dye (+75%). Conjugation pattern in bile showed that free sulfobromophthalein was increased by 57%, suggesting that hepatic conjugation was also impaired. This finding, however, could not fully explain the reduced sulfobromophthalein excretion since Tm of its non-metabolizable analog phenol-3,6-dibromophthalein was also decreased (-41%). Compartmental analysis of plasma decay of both dyes revealed that, whereas hepatic uptake was unaltered, canalicular excretion was reduced and reflux from the liver into plasma was increased by the cholestatic agent. Studies on transport of phenol-3,6-dibromophthalein by isolated hepatocytes showed that while uptake was unaffected, the treatment reduced (-36%) the release from hepatocytes preloaded with the dye. Neither glutathione S-transferase activity nor binding of sulfobromophthalein to cytosolic proteins was altered when evaluated in vitro, suggesting that reduced conjugation and enhanced sinusoidal reflux were not due to an irreversible effect of taurolithocholate on this enzyme. In conclusion, taurolithocholate impairs the hepatic transport of organic anions by impairing canalicular excretion and intrahepatic conjugation, as well as by increasing transfer from the liver into the plasma.

Progressive idiopathic cholestasis presenting with profuse watery diarrhoea and recurrent infections (Byler's disease)

The second child of healthy unrelated parents presented with chronic diarrhoea since the age of two months, initially associated with non-characteristic liver involvement. Recurrent infections, severe failure to thrive and various metabolic deficiencies complicated the further course, as well as profuse watery diarrhoea with elevated regulatory gut peptides, responding only to somatostatin analog treatment. At 22 months of age, intermittent cholestasis with permanently normal serum gamma-glutamyltransferase was evident. The child died of fulminant purulent meningitis at the age of three years six months. Liver histology showed intrahepatic cholestasis, bile duct paucity with focal proliferation as well as slight portal and intralobular fibrosis. The clinical, biochemical and histopathological findings were indicative of Byler's disease.

Fatal familial cholestatic syndrome in Greenland Eskimo children. A histomorphological analysis of 16 cases

We report the first detailed study of hepatic morphology in 28 biopsies from 16 Greenland Eskimo children with fatal familial cholestatic syndrome. The changes were categorized as early, intermediate and late. In the early stage, until 5 months of age, changes were restricted to zone 3, consisting of cholestasis and rosette formation without fibrosis. In the intermediate stage, from 5 to 14 months, cholestasis persisted and rosette formation increased, both with further extension into zone 2. Perisinusoidal fibrosis developed, first in zone 3 and later in zone 1. The late stage, from 17 to 60 months, showed a further increase in cholestasis and rosette formation, and fibrosis of zones 3 and 1 in nearly all biopsies. Portal to portal and portal to central fibrosis was evident with resulting cirrhosis in 2 of 7 patients. The morphological features can be summarized as pure cholestasis with prominent rosette formation followed by zone 3 fibrosis, zone 1 fibrosis, and, cirrhosis. Other characteristics are the virtual absence of inflammation and the lack of anatomical abnormalities such as paucity of bile ducts. The changes and their progression resemble those of Byler disease. Clinical and biochemical features are also largely similar, except for the presence of thrombocytosis in many of the Eskimo patients.

Partial external diversion of bile for the treatment of intractable pruritus associated with intrahepatic cholestasis

Partial diversion of bile flow to an external stoma was performed in 6 patients with chronic intrahepatic cholestasis with severe pruritus that had been refractory to medical measures. Four patients with progressive intrahepatic cholestasis and 2 with arteriohepatic dysplasia were treated. Follow-up has been 3-8 yr. Patients with progressive intrahepatic cholestasis have been free of itching since surgery. Serum bile salt concentrations fell from 218-275 microM (normal less than 10) before to less than 10 microM after surgery. Biochemical tests of liver function and histology returned to normal or near normal. Patients with arteriohepatic dysplasia had persistent mild pruritus after surgery. Serum bile salt concentrations fell from 153-317 to 25-37 microM. There was little or no improvement in biochemical tests or histology. Bile volume and bile salt diverted were higher in patients with progressive intrahepatic cholestasis (7.3-13.0 ml/kg.day and 83-137 mumol/kg.day, respectively) than those with arteriohepatic dysplasia (3.2-4.5 ml/kg.day and 21-36 mumol/kg.day). The quality of life since surgery has been excellent in patients with progressive intrahepatic cholestasis, but not as optimal in those with arteriohepatic dysplasia. These findings suggest that partial external biliary diversion can provide effective relief from pruritus and perhaps reversal of liver disease in patients with progressive intrahepatic cholestasis. It should be used in patients with arteriohepatic dysplasia only in those with disabling pruritus.

Fatal familial cholestatic syndrome in Greenland Eskimo children

A syndrome of intrahepatic cholestasis leading to death in early childhood was studied in 16 Greenland Eskimo children. The pedigrees are compatible with autosomal recessive inheritance. Jaundice, bleeding, pruritus, malnutrition, steatorrhoea, osteodystrophy and dwarfism were typical clinical features. Eight had died between the ages of six weeks and three years due to bleeding or infections. Hyperbilirubinaemia, profound hypoprothrombinaemia, thrombocytosis and elevated alkaline phosphatase levels were evident. Serum calcium, phosphate and parathyroid hormone levels indicated a secondary hyperparathyroidism. Hepatic fibrosis developed with increasing age. Follow-up of the surviving patients was 4 to 30 months. The aetiology of the disease is unknown. The syndrome has some features in common with previously described patients with familial intrahepatic cholestasis. No specific treatment is available. Genetic counselling is essential.