Intrahepatic cholestasis of pregnancy: three novel MDR3 gene mutations.
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BACKGROUND: The aetiology of intrahepatic cholestasis of pregnancy is unknown, but more than 10 different MDR3 gene mutations have recently been identified. AIM: To evaluate the genetic contribution of the MDR3 gene in the pathogenesis of intrahepatic cholestasis of pregnancy in Italian subjects. METHODS: We performed a multicentre prospective case-control study, enrolling 80 women with intrahepatic cholestasis of pregnancy at the third trimester of pregnancy and 80 pregnant women without intrahepatic cholestasis of pregnancy. Genomic DNA was extracted from peripheral venous blood leucocytes using standard procedures. The polymerase chain reaction was used to amplify exon 14 of the MDR3 gene and the polymerase chain reaction products were sequenced using a Big Dye Terminator Cycle Sequencing kit. RESULTS: Three novel non-synonymous heterozygous mutations in exon 14 were found (4%; E528D, R549H, G536R) among the 80 intrahepatic cholestasis of pregnancy patients, whereas the pregnant controls were all negative for exon 14 polymorphisms. The three patients involved had normal GGT and bilirubin, but high levels of both ALT and serum bile acids. One had cholesterol bile stones. The outcome of pregnancy was normal for two (with vaginal delivery), while foetal distress was recorded in the third. CONCLUSIONS: These three novel mutations add further information on the involvement of the MDR3 gene in intrahepatic cholestasis of pregnancy. As in other studies, we found only heterozygous mutations that could cause an impaired transport protein function, not its absence (which is responsible for more severe liver disease). Different genetic backgrounds might justify the presence of novel MDR3 gene mutations. (+info)
Medical treatment of cholestatic liver diseases: From pathobiology to pharmacological targets.
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Bile secretion is dependent on the coordinated functions of a number of hepatobiliary transport systems. Cholestasis may be caused by an impairment of bile secretion, an obstruction of bile flow or a combination of the two. The common consequence of all forms of cholestasis is retention of bile acids and other potentially toxic compounds in the hepatocytes leading to apoptosis or necrosis of hepatocytes and eventually to chronic cholestatic liver disease. In certain cholestatic disorders there is also leakage of bile acids into the peribiliary space causing portal inflammation and fibrosis. The following pharmacological targets for treatment of intrahepatic cholestasis can be identified: stimulation of orthograde biliary secretion and retrograde secretion of bile acids and other toxic cholephils into the systemic circulation for excretion via the kidneys to reduce their retention in the hepatocytes; stimulation of the metabolism of hydrophobic bile acids and other toxic compounds to more hydrophilic, less toxic metabolites; protection of injured cholangiocytes against toxic effects of bile; inhibition of apoptosis caused by elevated levels of cytotoxic bile acids; inhibition of fibrosis caused by leakage of bile acids into the peribiliary space. The clinical results of ursodeoxcholic acid therapy of primary biliary cirrhosis may be regarded as the first success of this strategy. (+info)
Intrahepatic cholestasis of pregnancy: the severe form is associated with common variants of the hepatobiliary phospholipid transporter ABCB4 gene.
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BACKGROUND: Intrahepatic cholestasis of pregnancy (ICP) is characterised by troublesome maternal pruritus, raised serum bile acid levels and increased fetal risk. Mutations of the ABCB4 gene encoding the hepatobiliary phospholipid transporter have been identified in a small proportion of patients with cholestasis of pregnancy. In a recent prospective study on 693 patients with cholestasis of pregnancy, a cut-off level for serum bile acid (> or =40 micromol/l) was determined for increased risk of fetal complications. OBJECTIVES: To investigate whether common combinations of polymorphic alleles (haplotypes) of the genes encoding the hepatobiliary ATP-binding cassette (ABC) transporters for phospholipids (ABCB4) and bile acids (ABCB11) were associated with this severe form of cholestasis of pregnancy. METHODS: For genetic analysis, 52 women with bile acid levels > or =40 micromol/l (called cases) and 52 unaffected women (called controls) matched for age, parity and geographical residence were studied. Gene variants tagging common ABCB4 and ABCB11 haplotypes were genotyped and haplotype distributions were compared between cases and controls by permutation testing. RESULTS: In contrast with ABCB11 haplotypes, ABCB4 haplotypes differed between the two groups (p = 0.019), showing that the severe form of cholestasis of pregnancy is associated with the ABCB4 gene variants. Specifically, haplotype ABCB4_5 occurred more often in cases, whereas haplotypes ABCB4_3 and ABCB4_7 were more common in controls. These associations were reflected by different frequencies of at-risk alleles of the two tagging polymorphisms (c.711A: odds ratio (OR) 2.27, p = 0.04; deletion intron 5: OR 14.68, p = 0.012). CONCLUSION: Variants of ABCB4 represent genetic risk factors for the severe form of ICP in Sweden. (+info)
Case of fatal sickle cell intrahepatic cholestasis despite use of exchange transfusion in an African-American patient.
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Sickle cell intrahepatic cholestasis (SCIC) is a rare complication of sickle cell anemia, characterized by marked hyperbilirubinemia and acute hepatic failure with an often fatal course. However, the few reported adult cases that were treated with exchange transfusion had a favorable outcome. We herein describe a 48-year-old African-American man with hemoglobin S/B thalassemia and previously treated hepatitis C with compensated cirrhosis, who presented with a total bilirubin of 59.7 mg/dL and direct bilirubin of 43.6 mg/dL in the absence of choledocholithiasis. Despite an exchange transfusion and aggressive packed red blood cell transfusions, which successfully decreased the hemoglobin S levels to <15%, he perished from progressive hepatic and renal failure. Autopsy demonstrated extensive intrahepatocellular and intracanalicular cholestasis in a background of cirrhosis. Our case suggests that poor prognostic factors for adult SCIC patients treated with exchange transfusion may include older age and underlying hepatic disease. (+info)
Incidence and risk factors for the development of prolonged and severe intrahepatic cholestasis after liver transplantation.
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Predictive factors for intrahepatic cholestasis after orthotopic liver transplantation (OLT) have not yet been established. We sought to identify the incidence and risk factors associated with prolonged severe intrahepatic cholestasis (PSIC) after OLT. We assessed 428 consecutive patients undergoing their first OLT. PSIC was diagnosed if a serum bilirubin concentration was greater than 100 micromol/L and/or a 3-fold increase of alkaline phosphatase occurred within the first month after OLT and was sustained for at least 1 week in the absence of biliary complications. Multivariable logistic regression identified factors independently associated with PSIC. PSIC developed in 107 patients (25%). Independent risk factors by multivariable analysis were intraoperative transfusion of cryoprecipitate and platelets; nonidentical blood group status; suboptimal organ appearance; inpatient status before transplantation; and bacteraemia in the first month after transplantation. In contrast, acute liver failure, older age, and higher levels of serum sodium and serum potassium were all associated with a reduced likelihood of developing PSIC in the first month. There were 47 deaths in the PSIC group (44%) as opposed to 65 deaths in the non-PSIC group (20%) after OLT. A poor preoperative clinical status in conjunction with a suboptimal graft was associated with PSIC after OLT. Avoidance of suboptimal livers and ABO nonidentical grafts for young patients with poor synthetic function and for pretransplant inpatients may lessen this complication and reduce the associated early mortality. (+info)
Role of Kupffer cells in the pathogenesis of liver disease.
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Kupffer cells, the resident liver macrophages have long been considered as mostly scavenger cells responsible for removing particulate material from the portal circulation. However, evidence derived mostly from animal models, indicates that Kupffer cells may be implicated in the pathogenesis of various liver diseases including viral hepatitis, steatohepatitis, alcoholic liver disease, intrahepatic cholostasis, activation or rejection of the liver during liver transplantation and liver fibrosis. There is accumulating evidence, reviewed in this paper, suggesting that Kupffer cells may act both as effector cells in the destruction of hepatocytes by producing harmful soluble mediators as well as antigen presenting cells during viral infections of the liver. Moreover they may represent a significant source of chemoattractant molecules for cytotoxic CD8 and regulatory T cells. Their role in fibrosis is well established as they are one of the main sources of TGFbeta1 production, which leads to the transformation of stellate cells into myofibroblasts. Whether all these variable functions in the liver are mediated by different Kupffer cell subpopulations remains to be evaluated. In this review we propose a model that demonstrates the role of Kupffer cells in the pathogenesis of liver disease. (+info)
Early histologic changes in fibrosing cholestatic hepatitis C.
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Recurrent hepatitis C (RHCV) after liver transplantation is almost universal, and occasional patients will have an aggressive course characterized histologically by pericellular/sinusoidal fibrosis and cholestasis, known as fibrosing cholestatic hepatitis (FCH). The early stages and evolution of this disease have not been well characterized. A total of 77 liver biopsies performed for indication (nonprotocol) were evaluated for necroinflammation, rejection, cholestasis, and fibrosis. Control groups were composed of protocol biopsies from HCV transplant patients (10 biopsies) as well as non-HCV transplant patients (6 biopsies). Scoring for necroinflammation, rejection, and fibrosis were compiled using standard criteria (hepatic activity index, Banff, Ishak, METAVIR). Pericellular fibrosis was staged with a novel "sinusoidal" system. A cholestasis scoring system was developed to quantitate parenchymal and portal features of cholestasis. Biopsies were categorized as rejection, RHCV, FCH, and stable based on histology and clinical information. FCH was found to have a higher fibrosis stage overall when compared to most diagnostic groups, regardless of the staging system used. Additionally, sinusoidal fibrosis was significantly higher in the FCH diagnosis group. Cholestasis was more prominent in biopsies of FCH in all comparisons. In conclusion, the presence of cholestasis and fibrosis with mild to moderate RHCV should raise the suspicion of FCH. When studying the evolution of these cases, the first abnormality to appear is RHCV and cholestasis, fibrosis develops soon after, and both continue to worsen until the point of allograft failure or patient death. (+info)
Novel resequencing chip customized to diagnose mutations in patients with inherited syndromes of intrahepatic cholestasis.
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BACKGROUND & AIMS: Inherited syndromes of intrahepatic cholestasis commonly result from mutations in the genes SERPINA1 (alpha(1)-antitrypsin deficiency), JAG1 (Alagille syndrome), ATP8B1 (progressive familial intrahepatic cholestasis type 1 [PFIC1]), ABCB11 (PFIC2), and ABCB4 (PFIC3). However, the large gene sizes and lack of mutational hotspots make it difficult to survey for disease-causing mutations in clinical practice. Here, we aimed to develop a technological tool that reads out the nucleotide sequence of these genes rapidly and accurately. METHODS: 25-mer nucleotide probes were designed to identify each base for all exons, 10 bases of intronic sequence bordering exons, 280-500 bases upstream from the first exon for each gene, and 350 bases of the second intron of the JAG1 gene and tiled using the Affymetrix resequencing platform. We then developed high-fidelity polymerase chain reactions to produce amplicons using 1 mL of blood from each subject; amplicons were hybridized to the chip, and nucleotide calls were validated by standard capillary sequencing methods. RESULTS: Hybridization of amplicons with the chip produced a high nucleotide sequence readout for all 5 genes in a single assay, with an automated call rate of 93.5% (range, 90.3%-95.7%). The accuracy of nucleotide calls was 99.99% when compared with capillary sequencing. Testing the chip on subjects with cholestatic syndromes identified disease-causing mutations in SERPINA1, JAG1, ATP8B1, ABCB11, or ABCB4. CONCLUSIONS: The resequencing chip efficiently reads SERPINA1, JAG1, ATP8B1, ABCB11, and ABCB4 with a high call rate and accuracy in one assay and identifies disease-causing mutations. (+info)