Genetic defects in bile acid conjugation cause fat-soluble vitamin deficiency.

BACKGROUND & AIMS: The final step in bile acid synthesis involves conjugation with glycine and taurine, which promotes a high intraluminal micellar concentration to facilitate lipid absorption. We investigated the clinical, biochemical, molecular, and morphologic features of a genetic defect in bile acid conjugation in 10 pediatric patients with fat-soluble vitamin deficiency, some with growth failure or transient neonatal cholestatic hepatitis. METHODS: We identified the genetic defect that causes this disorder using mass spectrometry analysis of urine, bile, and serum samples and sequence analysis of the genes encoding bile acid-CoA:amino acid N-acyltransferase (BAAT) and bile acid-CoA ligase (SLC27A5). RESULTS: Levels of urinary bile acids were increased (432 ± 248 µmol/L) and predominantly excreted in unconjugated forms (79.4% ± 3.9%) and as sulfates and glucuronides. Glycine or taurine conjugates were absent in the urine, bile, and serum. Unconjugated bile acids accounted for 95.7% ± 5.8% of the bile acids in duodenal bile, with cholic acid accounting for 82.4% ± 5.5% of the total. Duodenal bile acid concentrations were 12.1 ± 5.9 mmol/L, which is too low for efficient lipid absorption. The biochemical profile was consistent with defective bile acid amidation. Molecular analysis of BAAT confirmed 4 different homozygous mutations in 8 patients tested. CONCLUSIONS: Based on a study of 10 pediatric patients, genetic defects that disrupt bile acid amidation cause fat-soluble vitamin deficiency and growth failure, indicating the importance of bile acid conjugation in lipid absorption. Some patients developed liver disease with features of a cholangiopathy. These findings indicate that patients with idiopathic neonatal cholestasis or later onset of unexplained fat-soluble vitamin deficiency should be screened for defects in bile acid conjugation.

Hepatotoxicity from anabolic androgenic steroids marketed as dietary supplements: contribution from ATP8B1/ABCB11 mutations?

BACKGROUND: Though possession of androgenic anabolic steroids (AAS) is illegal, non-prescription use of AAS persists. METHODS: We describe two Caucasian males (aged 25 and 45 years) with cholestatic hepatitis following ingestion of the dietary supplement Mass-Drol ('Celtic Dragon') containing the AAS 2α-17α-dimethyl-etiocholan-3-one,17ß-ol. RESULTS: Despite substantial hyperbilirubinaemia peak gamma-glutamyl transferase (GGT) remained normal. Besides 'bland' intralobular cholestasis, liver biopsy in both found deficiency of canalicular expression of ectoenzymes as seen in ATP8B1 disease. In the older patient, bile salt export pump marking (encoded by ABCB11) was focally diminished. We hypothesized that AAS had either induced inhibition of normal ATP8B1/ABCB11 expression or triggered initial episodes of benign recurrent intrahepatic cholestasis (BRIC) type 1/or 2. On sequencing, ATP8B1 was normal in both patients although the younger was heterozygous for the c.2093G>A mutation in ABCB11, a polymorphism previously encountered in drug-induced liver injury. CONCLUSION: AAS marketed as dietary supplements continue to cause hepatotoxicity in the UK; underlying mechanisms may include unmasking of genetic cholestatic syndromes.

Mutations in TTC37 cause trichohepatoenteric syndrome (phenotypic diarrhea of infancy).

BACKGROUND & AIMS: Trichohepatoenteric syndrome (THES) is an autosomal-recessive disorder characterized by life-threatening diarrhea in infancy, immunodeficiency, liver disease, trichorrhexis nodosa, facial dysmorphism, hypopigmentation, and cardiac defects. We attempted to characterize the phenotype and elucidate the molecular basis of THES. METHODS: Twelve patients with classic THES from 11 families had detailed phenotyping. Autozygosity mapping was undertaken in 8 patients from consanguineous families using 250,000 single nucleotide polymorphism arrays and linked regions evaluated using microsatellite markers. Linkage was confirmed to one region from which candidate genes were analyzed. The effect of mutations on protein production and/or localization in hepatocytes and intestinal epithelial cells from affected patients was characterized by immunohistochemistry. RESULTS: Previously unrecognized platelet abnormalities (reduced platelet alpha-granules, unusual stimulated alpha granule content release, abnormal lipid inclusions, abnormal platelet canalicular system, and reduced number of microtubules) were identified. The THES locus was mapped to 5q14.3-5q21.2. Sequencing of candidate genes showed mutations in TTC37, which encodes the uncharacterized tetratricopeptide repeat protein, thespin. Bioinformatic analysis suggested thespin to be involved in protein-protein interactions or chaperone. Preliminary studies of enterocyte brush-border ion transporter proteins (sodium hydrogen exchanger 2, sodium hydrogen exchanger 3, aquaporin 7, sodium iodide symporter, and hydrogen potassium adenosine triphosphatase [ATPase]) showed reduced expression or mislocalization in all THES patients with different profiles for each. In contrast the basolateral localization of Na/K ATPase was not altered. CONCLUSIONS: THES is caused by mutations in TTC37. TTC37 mutations have a multisystem effect, which may be owing to abnormal stability and/or intracellular localization of TTC37 target proteins.

Follow-up in children with progressive familial intrahepatic cholestasis after partial external biliary diversion.

OBJECTIVES: The aim of this study was to examine whether reversion of histological fibrosis followed partial external biliary diversion (PEBD) in patients with progressive familial intrahepatic cholestasis (PFIC); whether the duration of cholestatic episodes after PEBD influenced the evolution of fibrosis; and whether genotyping was helpful in predicting outcome of PEBD. PATIENTS AND METHODS: Children with PFIC who underwent PEBD were investigated with genetic, biochemical, and anthropometric standard methods. Serial liver specimens were assessed histologically without knowledge of genotype and outcome. Findings were evaluated in the contexts of the total duration of cholestasis and the clinical outcome after PEBD. RESULTS: From a total of 18 children with PFIC, 13 underwent PEBD, and 12 of these (among them 10 with identified ABCB11 mutations) were amenable for clinical and histological follow-up. When compared with baseline at PEBD, statistically significant reductions were found in histological cholestasis 1 and 3 years after PEBD, and in fibrosis 5 and >10 years after PEBD. The relative duration of cholestatic episodes after PEBD was positively correlated with the severity of fibrosis. Children homozygous for the missense mutation c.890A>G in ABCB11 responded well to PEBD. CONCLUSIONS: Biliary diversion should be regarded as the first choice of surgical treatment in noncirrhotic patients with severe ABCB11 disease and may also be efficacious in other forms of PFIC.

Microsatellite instability in hepatocellular carcinoma in non-cirrhotic liver in patients older than 60 years.

AIM: Hepatocellular carcinoma (HCC) in otherwise normal liver is rare, its pathogenesis remains obscure and the literature on the subject is scarce. We investigated microsatellite instability (MSI) in eight elderly patients (median age 70.7, range 63-76 years) without a clinical history of liver disease and who underwent liver resection for HCC in otherwise normal background liver between 2001 and 2005 at King's College Hospital, London. METHODS: Immunohistochemistry for mutL homolog 1 (MLH1), mutS homolog 2 (MSH2), mutS homolog 6 (MSH6) and post-meiotic segregation increased 2 (PMS2) was carried out on formalin-fixed and paraffin-embedded sections of tumor and background liver. MSI analysis was performed using a panel of monomorphic microsatellites markers: BAT-25, BAT-26, NR21, NR24 and NR27 and pentaplex PCR. RESULTS: All HCC were solitary large tumors. Two also had satellite nodules. The background liver was usually unremarkable. There was nuclear expression of MLH1, MSH2, MSH6 and PMS2 in all tumors excluding a DNA mismatch repair defect. The same pattern of staining was noted in the hepatocytes of the background liver of all cases. No differences between microsatellite lengths in the background liver and in the tumor, as assessed in PCR products, were found for any of the five microsatellite markers in any patients. These findings provided no evidence for MSI. CONCLUSION: Our study showed that MSI is not implicated in the pathogenesis of a subset of HCC affecting elderly patients without chronic liver disease. Further studies are needed to clarify the pathogenesis of HCC in this particular setting.

Safety and efficacy of combined use of sildenafil, bosentan, and iloprost before and after liver transplantation in severe portopulmonary hypertension.

Portopulmonary hypertension (PPHTN) represents a constrictive pulmonary vasculopathy in patients with portal hypertension. Liver transplantation (LT) may be curative and is usually restricted to patients with mild-to-moderate disease severity characterized by a mean pulmonary artery pressure (mPAP < 35 mm Hg). Patients with severe disease (mPAP > 50 mm Hg) are usually excluded from transplantation. We describe a patient with severe PPHTN, initiated on sequential and ultimately combination therapy of prostacyclin, sildenafil, and bosentan (PSB) pretransplantation and continued for 2 years posttransplantation. Peak mPAP on PSB therapy was dramatically reduced from 70 mm Hg to 32 mm Hg pretransplantation, and continued therapy facilitated a further fall in mPAP to 28 mm Hg posttransplantation. The pulmonary vascular resistance index fell from 604 to 291 dyne second(-1) cm(-5). The perioperative mPAP rose to 100 mm Hg following an episode of sepsis and fell with optimization of PSB therapy. In conclusion, this is the first reported patient with severe PPHTN using this combination of vasodilator therapy as a bridge to LT and then as maintenance in the posttransplantation phase. This regimen may enable LT in similar patients in the future, without long-term consequences.

Auxiliary transplantation for acute liver failure: Histopathological study of native liver regeneration.

Auxiliary liver transplantation (ALT) permits the serial assessment of regeneration in livers of patients with acute liver failure (ALF). Forty-nine ALF patients [32 adults (median age, 23 years; range, 16-40 years) and 17 children (median age, 12 years; range, 1-15 years)] underwent ALT between 1994 and 2004 at King's College Hospital. Twenty-four patients had seronegative liver failure, 15 had acetaminophen toxicity, 4 had hepatitis B virus (HBV) infection, 3 had drug-induced liver failure, 2 had autoimmune hepatitis, and 1 had mushroom poisoning. Nine patients without post-ALT native liver histology were excluded from review. All acetaminophen-induced, HBV, and drug-related patients had diffuse injury. Twelve seronegative patients and the autoimmune hepatitis patient had a map-like injury. On follow-up, 9 acetaminophen-induced patients, 9 seronegative patients, 2 drug-induced ALF patients, 3 HBV patients, and the autoimmune patient recovered to a near-normal native liver with inconsequential scarring. The hepatocyte proliferative rate in diffuse necrosis was 27.4% (range, 3.1%-69.4%) at hepatectomy and sharply decreased after 8 days post-ALT, being minimal months and years after ALT. In conclusion, in patients undergoing ALT for ALF with a diffuse pattern of liver injury-mainly acetaminophen toxicity-hepatocyte proliferation occurs in the native liver within a few days of transplantation. If the injury is map-like (most cases of seronegative ALF), regeneration seems to involve variable hepatocellular proliferation and potential ductular hepatopoiesis, but sequential assessment is difficult because of sampling variation. The likelihood of histological recovery appears to be minimal in livers with total hepatocyte loss at the time of ALT.

Cystic biliary atresia: an etiologic and prognostic subgroup.

INTRODUCTION: Cystic biliary atresia (CBA) is an uncommon variant of biliary atresia (BA) in which prognosis may be relatively favorable but liable to misdiagnosis as choledochal cyst, and potentially offers insights into the etiology of BA. Because some cases can be detected antenatally, CBA in general may have its origins in utero life. We assessed our experience with CBA. METHODS: Single-center retrospective review of infants with CBA over a 13-year period (January 1994 to December 2006) was done. Data are given as medians (range). RESULTS: Of 270 infants with BA, 29 (9 male) were identified as CBA. Antenatal ultrasonography had detected an abnormality in 12 (41%) infants at a median of 22 weeks (17-34 weeks) of gestation. All infants underwent postnatal excision and Kasai portoenterostomy (KP). Those with antenatally detected CBA came to surgery younger (36 [14-67] vs 48 days [35-147 days], P = .004). Twenty cysts (69%) had a fibroinflammatory wall with no biliary epithelial lining and 6 (26%) contained bile. Age at KP was significantly and positively correlated (r = 0.46, P = .01) with liver fibrosis, as assessed in liver biopsy materials obtained at KP, but not with grade of "hepatocyte disarray" (P = .74). Twenty infants (69%) cleared their jaundice (bilirubin <20 mumol/L) within 6 months after KP. Age at KP markedly affected outcome. CONCLUSION: Cystic BA is a clinically distinct variant of BA. Despite onset in prenatal life, earlier than presumed for isolated BA, it has a better prognosis, particularly with early surgery.

Liver transplantation for HCV-related cirrhosis in a patient with gastric mucosa-associated lymphoma (MALToma) pretreated with rituximab.

End-stage liver disease due to chronic hepatitis C virus (HCV) infection is now the most frequent indication for liver transplantation. HCV infection is associated with extrahepatic disease including cryoglobulinemia and lymphoma. The number of patients requiring liver transplantation (LT) for cirrhosis secondary to HCV infection has increased over the past 10 years; consequently, associated extrahepatic manifestations (in particular hematological malignancies) will be more commonly observed in this patient group. The management of patients with both end-stage liver disease and significant HCV-related extrahepatic disease is undefined. We report a 59-year-old man in whom extranodal marginal-zone B-cell lymphoma arising in gastric mucosa-associated lymphoid tissue (MALToma) was successfully eradicated by rituximab administration and gastrectomy at LT for HCV-related cirrhosis. Our experience with rituximab in this patient suggests that it can be used safely in the setting of severe liver disease due to HCV infection. Rituximab may be useful in preventing progression of NHL until surgical extirpation is possible.

Outcomes of liver transplantation in HIV-infected individuals: the impact of HCV and HBV infection.

Liver transplantation (LT) in human immunodeficiency virus (HIV)-positive individuals is considered to be an experimental therapy with limited reported worldwide experience, and little long-term survival data. Published data suggest that the short-term outcome is encouraging in selected patients. Here, we report our experience in 14 HIV-infected liver allograft recipients, and compare outcomes between those coinfected with hepatitis C virus (HCV) and the non-HCV group. A total of 14 HIV-infected patients (12 male, 2 female, age range 26-59 years) underwent LT between January 1995 and April 2003. Indications for LT were HCV (n = 7), hepatitis B virus (HBV; n = 4), alcohol-induced liver disease (n = 2), and seronegative hepatitis (n = 1); 3 patients presented with acute liver failure. At LT, CD4 cell counts (T-helper cells that are targets for HIV) ranged from 124 to 500 cells/microL (mean 264), and HIV viral loads from <50 to 197,000 copies/mL. Nine of 12 patients were exposed to highly active antiretroviral therapy (HAART) before LT. In the non-HCV group (n = 7), all patients are alive, all surviving more than 365 days (range 668-2,661 days). No patient has experienced HBV recurrence, and graft function is normal in all 7 patients. However, 5 of 7 HCV-infected patients died after LT at 95-784 days (median 161 days). A total of 4 patients died of complications due to recurrent HCV infection and sepsis, despite antiviral therapy in 3 of them. A total of 3 patients experienced complications relating to HAART therapy. In conclusion, outcome of LT in HIV-infected patients with HBV or other causes of chronic liver disease indicates that LT is an acceptable therapeutic option in selected patients. However, longer follow-up in larger series is required before a conclusive directive can be provided for HCV / HIV coinfected patients requiring LT.