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Abstract Inflammatory bowel disease is defined by inflammation and immune dysregulation. This study investigated the effects of Gα13 liver-specific knockout (LKO) on proximal and distal colons of dextran sodium sulfate (DSS)-induced mice in conjunction with a high-fat diet (HFD). HFD improved body weight gain and disease activity index scores. Gα13LKO exerted no improvement. In the proximal colon, HFD augmented the DSS effect on Il6, which was not observed in Gα13LKO mice. In the distal colon, HFD plus DSS oppositely fortified an increase in Tnfa and Cxcl10 mRNA in Gα13LKO but not WT. Il6 levels remained unchanged. Bioinformatic approaches using Gα13LKO livers displayed bile acid and cholesterol metabolism-related gene sets. Cholic acid and chenodeoxycholic acid levels were increased in the liver of mice treated with DSS, which was reversed by Gα13LKO. Notably, mice treated with DSS showed a reduction in hepatic ABCB11, CYP7B1, CYP7A1, and CYP8B1, which was reversed by Gα13LKO. Overall, feeding HFD augments the effect of DSS on Il6 in the proximal colon of WT, but not Gα13LKO mice, and enhances DSS effect on Tnfa and Cxcl10 in the distal colon of Gα13LKO mice, suggesting site-specific changes in the inflammatory cytokines, potentially resulting from changes in BA synthesis and excretion.

Inflammatory bowel disease is defined by inflammation and immune dysregulation. This study investigated the effects of Gα13 liver-specific knockout (LKO) on proximal and distal colons of dextran sodium sulfate (DSS)-induced mice in conjunction with a high-fat diet (HFD). HFD improved body weight gain and disease activity index scores. Gα13LKO exerted no improvement. In the proximal colon, HFD augmented the DSS effect on Il6, which was not observed in Gα13LKO mice. In the distal colon, HFD plus DSS oppositely fortified an increase in Tnfa and Cxcl10 mRNA in Gα13LKO but not WT. Il6 levels remained unchanged. Bioinformatic approaches using Gα13LKO livers displayed bile acid and cholesterol metabolism-related gene sets. Cholic acid and chenodeoxycholic acid levels were increased in the liver of mice treated with DSS, which was reversed by Gα13LKO. Notably, mice treated with DSS showed a reduction in hepatic ABCB11, CYP7B1, CYP7A1, and CYP8B1, which was reversed by Gα13LKO. Overall, feeding HFD augments the effect of DSS on Il6 in the proximal colon of WT, but not Gα13LKO mice, and enhances DSS effect on Tnfa and Cxcl10 in the distal colon of Gα13LKO mice, suggesting site-specific changes in the inflammatory cytokines, potentially resulting from changes in BA synthesis and excretion. [ABSTRACT FROM AUTHOR]

The abnormal increase of Oddi sphincter pressure and total bile duct pressure may play an important role in the formation of cholesterol stones, but the specific molecular mechanism is still unclear. This study aims to investigate it through in vitro and in vivo experiments. A mouse model of Oddi sphincter dysfunction was constructed by stone-inducing diet. We compared the two groups with PKC-α inhibitor GÖ6976 and PKC-α agonist thymeleatoxin. Oddi sphincter pressure and total bile duct pressure were measured. Biochemical analysis of total cholesterol, bile acid and bilirubin was then conducted. The histopathologic changes of bile duct were observed by HE staining and the ultrastructure of liver cells and surrounding tissues was observed by transmission electron microscopy. Through the above experiments, we found that the change of PKC-α expression may affect the formation process of gallstones. The relationship between PKC-α and ABCB11 was further verified by in vitro and in vivo experiments. Our results suggest that ABCB11 and PKC-α are co-expressed in the tubule membrane of hepatocytes and interact with each other in hepatocytes. The high cholesterol diet further enhances the activation of PKC-α and thus reduces the expression of ABCB11. The formation of cholesterol stones is associated with the down-regulation of ABCB11 expression in the tubule membrane of hepatocytes due to kinase signaling. This is the first study to demonstrate that sphincter of Oddi dysfunction induces gallstones through PKC-α inhibition of ABCB11 expression. [ABSTRACT FROM AUTHOR]

Аim: to highlight the importance of broad differential diagnosis and possibility of conversion of benign recurrent intrahepatic cholestasis type 2 into more aggressive clinical phenotype.Key points. A 19-year-old female patient was admitted to the Clinic with skin pruritus, jaundice, dark urine, clay-colored stool, and general fatigue. Past medical history was significant for recurrent aforementioned symptoms since 3 years old, that relapsed every 1–2 years and were usually ameliorated with conservative therapy. During recent years, frequency of relapses and recovery period increased, at the same time effectiveness of medical therapy decreased. Blood chemistry results revealed an elevation of total bilirubin (up to 634 μmol/L), direct bilirubin (up to 354 μmol/L), bile acids (up to 510 μmol/L) and normal gamma glutamyl transferase level. Workup was negative for viral hepatitis, autoimmune liver diseases, obstructive choledochal lesions, storage diseases, although mutation in gene ABCB11 was found. Benign recurrent intrahepatic cholestasis type 2 was diagnosed. Following conservative therapy and plasmapheresis, jaundice and skin pruritus significantly diminished, levels of bilirubin and bile acids normalized. Regular follow up, liver biopsy and measures for relapse prevention given clinical features of aggressive phenotype were recommended.Conclusion. Identification of etiology of cholestatic liver diseases requires broad differential diagnosis. Clinical course of patients with benign recurrent intrahepatic cholestasis may transform into aggressive phenotype, reminiscent of progressive familial intrahepatic cholestasis.

Objectives: The aim of this study is to reveal the diagnostic yield of the progressive familial intrahepatic cholestasis (PFIC) gene panel that we have used in the diagnosis of this patient group, which accounts for approximately 10% of cholestatic liver disease, and to report the clinical findings of our patients with the detected variants. Methods: In this study, we retrospectively evaluated the results of molecular genetic analysis of pediatric patients whose PFIC gene panel contained the ATP8B1, ABCB11, and ABCB4 genes. Results: In 10 patients, 12 different variants were detected that could explain the PFIC clinical picture. Three of these variants were considered novel variants. Conclusions: Our study demonstrates the usefulness of the NGS panel in diagnosing pediatric patients with PFIC findings. This diagnostic method also contributed to the variant spectrum of PFIC-related genes. [ABSTRACT FROM AUTHOR]

Background: Few reports of benign recurrent intrahepatic cholestasis (BRIC) have focused on East Asian patients. We describe the clinicopathologic features, genetics, treatment, and outcomes in Japanese BRIC patients. Methods: We recruited patients with BRIC type 1 (BRIC-1) or 2 (BRIC-2) treated at four pediatric centers and one adult center between April 2007 and March 2022. Demographics, clinical course, laboratory results, molecular genetic findings concerning ATP8B1 and ABCB11 genes, histopathology, and treatment response were examined retrospectively. Results: Seven Japanese patients with BRIC were enrolled (four male, three female; four BRIC-1 and three BRIC-2). The median age at onset for BRIC-1 was 12 years; for BRIC-2, it was 1 month. Intermittent cholestatic attacks numbered from one to eight during the 11 years of median follow-up. Six patients received a mainstream education; only one patient attended special education. None developed cirrhosis. Three with BRIC-1 showed compound heterozygosity for a variant ATP8B1 gene, while one was heterozygous; two BRIC-2 patients showed compound heterozygosity in ABCB11 and one was heterozygous. Liver biopsy specimens obtained during cholestatic attacks showed fibrosis varying from none to moderate; inflammation was absent or mild. Rifampicin administered to three patients for cholestatic attacks was effective in all, as was cholestyramine in two of three. Conclusions: To our knowledge, this is the first East Asian multicenter study of BRIC patients. Onset age and number of cholestatic attacks varied. Rifampicin and cholestyramine were effective against attacks. No patient developed cirrhosis; most had normal growth and development. The long-term outcomes were satisfactory. [ABSTRACT FROM AUTHOR]

Head and neck squamous cell carcinomas (HNSCC) are at a high risk of recurrence and multimodal therapy have not significantly improved survival in recent decades. Although immune checkpoint inhibitors (ICIs) are effective in a small proportion of HNSCC patients, the majority do not respond. In this study, we for the first time revealed that xenobiotic metabolic process was significantly associated with resistance to programmed death-1 (PD-1)/programmed death-ligand 1 (PD-L1) inhibitors in HNSCC and found that ATP binding cassette subfamily B member 11 (ABCB11) accumulated in immature tertiary lymphoid structures (TLSs) predicted worse progression-free survival (PFS) and overall survival (OS) after PD-1/PD-L1 inhibitors therapy. Moreover, the expression of cytochrome P450 1A2 (CYP1A2), a cytochrome P450 (CYP) enzyme that participates in xenobiotic metabolic process, was significantly upregulated in CD45+ABCB11+ tumor-infiltrating lymphocytes (TILs) compared with CD45+ABCB11−TILs in HNSCC tissues. Whole slide scans of 110 HNSCC tissues with hematoxylin-eosin (HE) and multispectral immuno-fluorescent (mIF) staining revealed that ABCB11 had a high co-expression with CYP1A2 in immature TLSs, and colocalization of ABCB11 and CYP1A2 in immature TLs significantly associated with high infiltration of immunosuppressive T-regulatory (Treg). Our study revealed that ABCB11 accumulated in immature TLSs might upregulate CYP1A2 to mediate xenobiotic metabolic process, thus increase the immunosuppressive Treg infiltration, and induce resistance to PD-1/PD-L1 inhibitors in HNSCC.

Progressive familial intrahepatic cholestasis type 2 (PFIC2) is a rare disorder caused by variants in the ABCB11 gene encoding the bile salt export pump (BSEP). We investigated the molecular defect in a PFIC2 infant and rescued the splicing defect with antisense oligonucleotides (ASOs). Whole-exome sequencing (WES) revealed compound heterozygous variants in the ABCB11 gene in a PFIC2 patient. Liver biopsy was immunostained for BSEP. The splicing effect of the candidate variants was investigated by minigene assay. ASOs were designed to rescue aberrant splicing. A Chinese girl of two nonconsanguineous healthy parents suffered from low glutamyl transpeptidase cholestasis and showed no response to the ursodeoxycholic acid. WES revealed that the patient was compound heterozygous for two novel variants in the ABCB11 gene: c.76+29T>G and c.390–2A>G. Liver immunohistochemistry showed the absence of BSEP. The variant c.76+29T>G was confirmed to retain 42 bp in the mature mRNA. The variant c.390–2A>G was confirmed to cause exon 6 skipping. We designed two ASOs and identified one of them that efficiently induced pseudoexon exclusion. We reported two novel variants of the ABCB11 gene, c.76+29T>G and c.390-2A>G, in a PFIC2 infant, thereby expanding the genotype of PFIC2. Our findings provide evidence for ASOs as a therapeutic approach for PFIC2 patients carrying intronic variants. [ABSTRACT FROM AUTHOR]

Abstract Background Progressive familial intrahepatic cholestasis is a rare, heterogeneous group of liver disorders of autosomal recessive inheritance, characterised by an early onset of cholestasis with pruritus and malabsorption, which rapidly progresses, eventually culminating in liver failure. For children and their parents, PFIC is an extremely distressing disease. Significant pruritus can lead to severe cutaneous mutilation and may affect many activities of daily living through loss of sleep, irritability, poor attention, and impaired school performance. Methods Databases including MEDLINE and Embase were searched for publications on PFIC prevalence, incidence or natural history, and the economic burden or health-related quality of life of patients with PFIC. Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines were followed. Results Three systematic reviews and twenty-two studies were eligible for inclusion for the epidemiology of PFIC including a total of 2603 patients. Study periods ranged from 3 to 33 years. Local population prevalence of PFIC was reported in three studies, ranging from 9.0 to 12.0% of children admitted with cholestasis, acute liver failure, or splenomegaly. The most detailed data come from the NAPPED study where native liver survival of >15 years is predicted in PFIC2 patients with a serum bile acid concentration below 102 µmol/L following bile diversion surgery. Burden of disease was mainly reported through health-related quality of life (HRQL), rates of surgery and survival. Rates of biliary diversion and liver transplant varied widely depending on study period, sample size and PFIC type, with many patients have multiple surgeries and progressing to liver transplant. This renders data unsuitable for comparison. Conclusion Using robust and transparent methods, this systematic review summarises our current knowledge of PFIC. The epidemiological overview is highly mixed and dependent on presentation and PFIC subtype. Only two studies reported HRQL and mortality results were variable across different subtypes. Lack of data and extensive heterogeneity severely limit understanding across this disease area, particularly variation around and within subtypes.

[Display omitted] ATP-binding cassette (ABC) transporters constitute a 49-member superfamily in humans. These proteins, most of them being transmembrane, allow the active transport of an important variety of substrates across biological membranes, using ATP hydrolysis as an energy source. For an important proportion of these ABC transporters, genetic variations of the loci encoding them have been correlated with rare genetic diseases, including cystic fibrosis and interstitial lung disease (variations in CFTR/ABCC7 and ABCA3) as well as cholestatic liver diseases (variations in ABCB4 and ABCB11). In this review, we first describe these ABC transporters and how their molecular dysfunction may lead to human diseases. Then, we propose a classification of the genetic variants according to their molecular defect (expression, traffic, function and/or stability), which may be considered as a general guideline for all ABC transporters' variants. Finally, we discuss recent progress in the field of targeted pharmacotherapy, which aim to correct specific molecular defects using small molecules. In conclusion, we are opening the path to treatment repurposing for diseases involving similar deficiencies in other ABC transporters. [ABSTRACT FROM AUTHOR]

Progressive familial intrahepatic cholestasis (PFIC) is a rare genetically heterogeneous group of autosomal recessive liver disorders that manifests as intrahepatic cholestasis during the neonatal period. ATP8B1, ABCB11, and ABCB4 genes are responsible for PFIC type 1, PFIC type 2, and PFIC type 3, respectively. To determine the underlying molecular etiology of PFIC, 80 patients from 77 families were investigated. The molecular genetic diagnosis was applied by using next‐generation sequencing (NGS) and revealed 29 different variants from 32 patients. In this study, we evaluated these variants according to mechanisms, clinical sub‐groups, and genotype‐phenotype correlation. [ABSTRACT FROM AUTHOR]

Drug-induced liver injury (DILI) is an unpredictable and feared side effect of antituberculosis treatment (AT). The present study aimed to identify clinical and genetic variables associated with susceptibility to AT-associated hepatotoxicity in patients with pulmonary tuberculosis treated with a standard protocol. Of 233 patients enrolled, 90% prospectively, 103 developed liver injury: 37 with mild and 66 with severe phenotype (DILI). All patients with mild hepatitis had a RUCAM score ≥4 and all patients with DILI had a RUCAM score ≥ 6. Eight clinical variables and variants in six candidate genes were assessed. A logistic multivariate regression analysis identified four risk factors for AT-DILI: age ≥ 55 years (OR:3.67; 95% CI:1.82–7.41; p < 0.001), concomitant medication with other hepatotoxic drugs (OR:2.54; 95% CI:1.23–5.26; p = 0.012), NAT2 slow acetylator status (OR:2.46; 95% CI:1.25–4.84; p = 0.009), and carriers of p.Val444Ala variant for ABCB11 gene (OR:2.06; 95%CI:1.02–4.17; p = 0.044). The statistical model explains 24.9% of the susceptibility to AT-DILI, with an 8.9 times difference between patients in the highest and in the lowest quartiles of risk scores. This study sustains the complex architecture of AT-DILI. Prospective studies should evaluate the benefit of NAT2 and ABCB11 genotyping in AT personalization, particularly in patients over 55 years. [ABSTRACT FROM AUTHOR]

Objective: Intrahepatic cholestasis of pregnancy (ICP) is a liver disorder of pregnancy characterized by pruritus, elevated liver enzymes and fasting serum bile acids. Genetic predisposition has been suggested to play a role in its etiology and mutations in the ATP8B1(OMIM ∗602397) (FIC1), ABCB11(OMIM ∗603201) (BSEP), and ABCB4(OMIM ∗171060) (MDR3) genes have been implicated.In the present study, we aimed to investigate the possible role of ATP8B1, ABCB11, and ABCB4 gene mutations in the patients with ICP. Materials and methods: A total of 25 patients who were diagnosed with ICP were included in the study. Genetic test results and mutation status of the patients as assessed by the next-generation sequencing technology were retrospectively retrieved from the hospital database. Results: Of all patients, significant alterations in the ATP8B1 (n = 2), ABCB11 (n = 1), and ABCB4 (n = 7) genes were observed in 10 patients using the molecular analysis testing. All these alterations were heterozygous. Of these alterations, four were reported in the literature previously, while six were not. Using the in-silico parameters, there was a pathogenic alteration in the ABCB4 gene in one patient, while there was no clinically relevant alteration in the other gene mutations in the remaining nine patients. Conclusion: Considering the fact that the alterations were compatible with clinical presentations of the ICP patients and the incidence of these mutations is low in the general population, we believe that our study results are clinically relevant. Further molecular genetic tests in ICP patients and functional studies supporting the results would shed light into the clinical importance of these alterations.

ABCB11 deficiency, formerly benign recurrent intrahepatic cholestasis (BRIC) is a very rare hereditary disorder characterized by the recurrent and intermittent episodes of cholestasis, jaundice, and pruritus. We report the case of a 12-year-old boy presenting with recurrent episodes of jaundice and severe pruritis since childhood. An extensive workup was done to rule out all the possible etiologies. Liver biopsy was done and histopathology was consistent with intrahepatic cholestasis. Immunohistochemistry, enzyme studies, and genetic testing confirmed the diagnosis. The patient was treated with Ursodeoxycholicacid and is on regular follow-up. We report this case due to the rarity of the disease in South India and to highlight the importance of genetic testing, which is the gold standard for diagnosis as well as for the classification of the disease. These patients should be under regular follow-up as those with fibrosis progression are at a risk for cholangiocarcinoma and hepatocellular carcinoma.

Background: Cholestatic disorders are divided in the extra and intra-hepatic that created due to the severe liver diseases. ABCB11 encodes the bile salt export pump and this gene is mutated in several forms of intrahepatic cholestasis. So far, some molecular features of this gene was studies. Objective: Using a developed web server, we identified high number of rare codons in this gene, and four cases were related to BSEP-deficient patients which can be used for drug design. Material and Methods: By in-silico modelling of ABCB11, some of rare codons in different locations of ATP8b1 gene were identified and evaluated. Using several web servers a number of mutations that converted non-rare codons to rare codon in these patients were identified. Results: Some of these rare Codons were located at special positions by mutation of which, the new side chains do not seem suitable for protein structure and function. Furthermore, this mutation changed the protein folding rate that may have a critical role in proper folding. Thus, primary change of these codons contributes to BSEP deficiency. Conclusion: This work is a comprehensive analysis of rare codons of ABCB11 and assessment of a number of these rare codon in protein levels. Rare codons evaluation can enhance our understanding of ABCB11 structural protein of ABCB11, and help us to develop mutation-specific therapies in design of new drugs. Citation: Zarenezhad M, Dehghani S. M, Ejtehadi F, Fattahi M. R, Mortazavi M, Tabei S. M. B. Evaluation of Hidden Information in ABCB11 Gene Mutations. J Biomed Phys Eng. 2019;9(3):303-316. https://doi.org/10.31661/jbpe.v9i3Jun.680.

Background: Progressive familial intrahepatic cholestasis is a rare, heterogeneous group of liver disorders of autosomal recessive inheritance, characterised by an early onset of cholestasis with pruritus and malabsorption, which rapidly progresses, eventually culminating in liver failure. For children and their parents, PFIC is an extremely distressing disease. Significant pruritus can lead to severe cutaneous mutilation and may affect many activities of daily living through loss of sleep, irritability, poor attention, and impaired school performance.Methods: Databases including MEDLINE and Embase were searched for publications on PFIC prevalence, incidence or natural history, and the economic burden or health-related quality of life of patients with PFIC. Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines were followed.Results: Three systematic reviews and twenty-two studies were eligible for inclusion for the epidemiology of PFIC including a total of 2603 patients. Study periods ranged from 3 to 33 years. Local population prevalence of PFIC was reported in three studies, ranging from 9.0 to 12.0% of children admitted with cholestasis, acute liver failure, or splenomegaly. The most detailed data come from the NAPPED study where native liver survival of >15 years is predicted in PFIC2 patients with a serum bile  acid concentration below 102 µmol/L following bile diversion surgery. Burden of disease was mainly reported through health-related quality of life (HRQL), rates of surgery and survival. Rates of biliary diversion and liver transplant varied widely depending on study period, sample size and PFIC type, with many patients have multiple surgeries and progressing to liver transplant. This renders data unsuitable for comparison.Conclusion: Using robust and transparent methods, this systematic review summarises our current knowledge of PFIC. The epidemiological overview is highly mixed and dependent on presentation and PFIC subtype. Only two studies reported HRQL and mortality results were variable across different subtypes. Lack of data and extensive heterogeneity severely limit understanding across this disease area, particularly variation around and within subtypes. [ABSTRACT FROM AUTHOR]

Background & Aims: ABCB11 deficiency presenting in infancy is believed generally to manifest as persistent/progressive cholestasis. We describe a group of patients with biallelic ABCB11 variants whose disorder manifested as transient neonatal cholestasis (TNC). Methods: Neonatal intrahepatic cholestasis in 68 children (31 males) with biallelic predictedly pathogenic variants (PPV) in ABCB11 was classified as transient (TNC group, n = 23, 11 males), intermittent (benign recurrent intrahepatic cholestasis [BRIC] group, n = 3, 1 male) or persistent/ progressive (progressive familial intrahepatic cholestasis [PFIC] group, n = 42, 19 males). Clinical, genetic and bile salt export pump (BSEP) expression information was correlated with outcomes. Results: The median onset age of jaundice was 3 days (birth to 2 months) for the TNC group and 10.5 days (birth to 3 months) for the PFIC group (P =.034). The median length of follow‐up of TNC patients was 44 months (12 months‐168 months). At presentation, hepatobiliary‐injury biomarker values were similar between the groups (P >.05). TNC patients (17/23) more often than PFIC patients (20/42, P =.041) harboured biallelic non‐null variants (predicted not to terminate translation prematurely). TNC patient livers (7/7) more often than PFIC patient livers (5/16, P =.005) expressed immunohistochemically detectable BSEP. Kaplan‐Meier analysis showed better prognosis for patients with BSEP expression (P =.009). Too few BRIC patients were available for statistical study. Conclusions: Neonatal cholestasis associated with biallelic PPV in ABCB11 can resolve temporarily or persistently in one third of cases. Resolution is more likely in patients with biallelic non‐null PPV or with liver BSEP expression. [ABSTRACT FROM AUTHOR]

Mutations in ABCB11 can cause deficiency of the bile salt export pump (BSEP), leading to cholestasis and end-stage liver disease. Owing to the rarity of the disease, the associations between genotype and natural history, or outcomes following surgical biliary diversion (SBD), remain elusive. We aimed to determine these associations by assembling the largest genetically defined cohort of patients with severe BSEP deficiency to date. This multicentre, retrospective cohort study included 264 patients with homozygous or compound heterozygous pathological ABCB11 mutations. Patients were categorized according to genotypic severity (BSEP1, BSEP2, BSEP3). The predicted residual BSEP transport function decreased with each category. Genotype severity was strongly associated with native liver survival (NLS, BSEP1 median 20.4 years; BSEP2, 7.0 years; BSEP3, 3.5 years; p <0.001). At 15 years of age, the proportion of patients with hepatocellular carcinoma was 4% in BSEP1, 7% in BSEP2 and 34% in BSEP3 (p = 0.001). SBD was associated with significantly increased NLS (hazard ratio 0.50; 95% CI 0.27–0.94: p = 0.03) in BSEP1 and BSEP2. A serum bile acid concentration below 102 μmol/L or a decrease of at least 75%, each shortly after SBD, reliably predicted NLS of ≥15 years following SBD (each p <0.001). The genotype of severe BSEP deficiency strongly predicts long-term NLS, the risk of developing hepatocellular carcinoma, and the chance that SBD will increase NLS. Serum bile acid parameters shortly after SBD can predict long-term NLS. This study presents data from the largest genetically defined cohort of patients with severe bile salt export pump deficiency to date. The genotype of patients with severe bile salt export pump deficiency is associated with clinical outcomes and the success of therapeutic interventions. Therefore, genotypic data should be used to guide personalized clinical care throughout childhood and adulthood in patients with this disease. • NAPPED is the largest global database of genotyped patients with BSEP deficiency. • The genotype of patients with BSEP deficiency predicts survival with native liver. • Genotype predicts long-term benefit of interruption of enterohepatic circulation. • Serum bile acids can be a surrogate marker for long-term outcome. • Treatment of patients with BSEP deficiency should be based on genotype. [ABSTRACT FROM AUTHOR]

Background: Many studies indicate that gallstone formation has genetic components. The abnormal expression of lipid-related genes could be the basis for particular forms of cholesterol gallstone disease. The aim of this study was to obtain insight into lipid metabolism disorder during cholesterol gallstone formation and to evaluate the effect of ursodeoxycholic acid (UDCA) on the improvement of bile lithogenicity and its potential influence on the transcription of lipid-related genes. Methods: Gallstone-susceptible mouse models were induced by feeding with a lithogenic diet (LD) for 8 weeks. Bile and liver tissues were obtained from these mouse models after 0, 4 and 8 weeks. Bile lipids were measured enzymatically, and the cholesterol saturation index (CSI) was calculated to evaluate the bile lithogenicity by using Carey's critical tables. Real-time polymerase chain reaction (RT-PCR) was used to detect the mRNA expression levels of farnesoid X receptor (FXR), liver X receptor (LXR), adenosine triphosphate-binding cassette subfamily G member 5/8 (ABCG5/8), cholesterol 7-α hydroxylase (CYP7A1), oxysterol 7-α hydroxylase (CYP7B1), sterol 27-α hydroxylase (CYP27A1), peroxisome proliferator-activated receptor alpha (PPAR-α) and adenosine triphosphate-binding cassette subfamily B member 11 (ABCB11). Results: The rate of gallstone formation was 100% in the 4-week group but only 30% in the UDCA-treated group. The UDCA-treated group had a significantly lower CSI compared with other groups. Of special note, the data on the effects of UDCA showed higher expression levels of ABCG8, ABCB11 and CYP27A1, as well as lower expression levels of LXR and PPAR-α, compared to the model control group. Conclusions: UDCA exhibits tremendously potent activity in restraining lipid accumulation, thus reversing the lithogenic effect and protecting hepatocytes from serious pathological damage. The abnormal expression of ABCG8, CYP7A1, CYP27A1, LXR and PPAR-α might lead to high lithogenicity of bile. These results are helpful in exploring new lipid metabolism pathways and potential targets for the treatment of cholesterol stones and for providing some basis for the study of the pathogenesis and genetic characteristics of cholelithiasis. Research on the mechanism of UDCA in improving lipid metabolism and bile lithogenicity may be helpful for clinical treatment and for reducing the incidence of gallstones. [ABSTRACT FROM AUTHOR]

Progressive Familial Intrahepatic Cholestasis type 2 (PFIC2) is a rare cholestatic disorder diagnosed in infancy or childhood that can lead to severe hepatic fibrosis and liver failure. Mutations in the ABCB11 gene result in a deficiency of the bile salt export protein (BSEP) and accumulation of bile inside the hepatocytes. Hepatocellular carcinoma is another condition associated with severe forms of deletion mutations in the ABCB11 gene. Treatment options including ursodeoxycholic acid biliary diversion have mixed outcomes and some patients require liver transplantation. Here, we describe two siblings with an extremely mild form of PFIC2 inherited from heterozygous parents. The elder sibling had acute liver failure at the age of six months and both siblings had pruritus, cholestasis, coagulopathy and fat-soluble-vitamin deficiencies in infancy but have been asymptomatic past infancy. Genetic testing of the siblings revealed that each were compound heterozygotes for two missense mutations of the ABCB11 gene: p.C68Y and p.R832H. Medical treatment typical for PFIC2 has not been necessary for either patient. This is the first report of these variants following a mild course in two affected patients.

Background. Intrahepatic cholestasis of pregnancy (ICP) is the most common liver disorder during gestation. The exact pathogenesis of ICP is multifactorial and still unclear. Therefore, our study aimed to check whether the selected ABCB4and ABCB11nucleotide variants are associated with an increased risk of ICP. Methods. ICP was diagnosed based on clinical symptoms characteristic of this disease and confirmed by increase in serum bile acids and transaminases, spontaneous resolution of clinical symptoms and normalization of laboratory tests after delivery. The total of 86 pregnant women meeting the criteria were included into the study. Healthy pregnant women with uncomplicated pregnancy served as control group (n=310). Sixcommon nucleotide variants in theABCB11and ABCB4genes were genotypedwith the use of high-resolution melting curve analysis. Conclusions. Our study did not show any significant association of analysed ABCB4and ABCB11nucleotide variants with the increased risk of intrahepatic cholestasis of pregnancy.

Progressive familial intrahepatic cholestasis (PFIC) is a heterogeneous group of disorders characterized by defective secretion of bile acids or transport defects resulting in progressive cholestasis. These disorders usually present during infancy or childhood and are associated with progressive liver disease. PFIC is estimated to affect 1 in 50,000-100,000 births, with PFIC-2 representing half of PFIC cases. PFIC-2 presents with hepatosplenomegaly, jaundice, pruritus, fat-soluble vitamin deficiencies, and growth failure. Laboratory findings include low/normal gamma glutamyl transpeptidase levels and elevated bilirubin, transaminases, and alpha-fetoprotein levels. In this report, we present a case of PFIC-2 presenting with severe coagulopathy, bruising, subcutaneous hematomas, and acute-onset anemia., (© 2024 The Author(s). Published by Wolters Kluwer Health, Inc. on behalf of The American College of Gastroenterology.)

Introduction. Intrahepatic cholestasis of pregnancy (ICP) is the most common liver disorder during gestation. The exact pathogenesis of ICP is multifactorial and still unclear. Therefore, our study aimed to check whether the selected ABCB4 and ABCB11 nucleotide variants are associated with an increased risk of ICP. Material and Methods. ICP was diagnosed based on clinical symptoms characteristic of this disease, and confirmed by an increase in serum bile acids and transaminases, spontaneous resolution of clinical symptoms, and normalisation of laboratory tests after delivery. A total of 86 pregnant women meeting the criteria were included in the study. Healthy pregnant women with uncomplicated pregnancy served as a control group (n = 310). Six common nucleotide variants in the ABCB11 and ABCB4 genes were genotyped with the use of high-resolution melting curve analysis. Results. All tested nucleotide variants did not show significant deviation from the Hardy Weinberg equilibrium in both ICP patients and healthy women. None of the ABCB4 and ABCB11 variants were significantly correlated with the risk of ICP (ptrend > 0.05). Similar results were also obtained after the division of patients based on the TBA levels. However, in the group of patients with moderate and severe ICP, a trend toward association between the ABCB4 rs2109505 variant and cholestasis was observed (ptrend = 0.063; ORallelic = 1.87, 95% CI: 0.92 -- 3.80; ORdominant = 1.90, 95% CI: 0.83 -- 4.36 and ORrecessive = 12.24, 95% CI: 0.74 -- 201.75). Conclusions. Our study did not show any significant association of the analysed ABCB4 and ABCB11 nucleotide variants with an increased risk of intrahepatic cholestasis of pregnancy. [ABSTRACT FROM AUTHOR]

Background: Cholestatic disorders are divided in the extra and intra-hepatic that created due to the severe liver diseases. ABCB11 encodes the bile salt export pump and this gene is mutated in several forms of intrahepatic cholestasis. So far, some molecular features of this gene was studies. Objective: Using a developed web server, we identified high number of rare codons in this gene, and four cases were related to BSEP-deficient patients which can be used for drug design. Material and Methods: By in-silico modelling of ABCB11, some of rare codons in different locations of ATP8b1 gene were identified and evaluated. Using several web servers a number of mutations that converted non-rare codons to rare codon in these patients were identified. Results: Some of these rare Codons were located at special positions by mutation of which, the new side chains do not seem suitable for protein structure and function. Furthermore, this mutation changed the protein folding rate that may have a critical role in proper folding. Thus, primary change of these codons contributes to BSEP deficiency. Conclusion: This work is a comprehensive analysis of rare codons of ABCB11 and assessment of a number of these rare codon in protein levels. Rare codons evaluation can enhance our understanding of ABCB11 structural protein of ABCB11, and help us to develop mutation-specific therapies in design of new drugs. [ABSTRACT FROM AUTHOR]

Benign recurrent intrahepatic cholestasis (BRIC), a rare cause of cholestasis, is characterized by recurrent episodes of cholestasis without permanent liver damage. BRIC type 2 (BRIC2) is an autosomal recessive disorder caused by ABCB11 mutations. A 6-year-old girl had recurrent episodes of jaundice. At two months of age, jaundice and hepatosplenomegaly developed. Liver function tests showed cholestatic hepatitis. A liver biopsy revealed diffuse giant cell transformation, bile duct paucity, intracytoplasmic cholestasis, and periportal fibrosis. An ABCB11 gene study revealed novel compound heterozygous mutations, including c.2075+3A>G in IVS17 and p.R1221K. Liver function test results were normal at 12 months of age. At six years of age, steatorrhea, jaundice, and pruritus developed. Liver function tests improved following administration of phenylbutyrate and rifampicin. Her younger brother developed jaundice at two months of age and his genetic tests revealed the same mutations as his sister. This is the first report of BRIC2 confirmed by ABCB11 mutations in Korean siblings. [ABSTRACT FROM AUTHOR]

Benign recurrent intrahepatic cholestasis is a rare disorder characterized by recurrent episodes of cholestatic jaundice without liver damage. A mutation in the ABCB11 gene encoding bile salt export pump protein causes the disease. A 16-year-old boy with severe jaundice is presented here. His laboratory tests were consistent with intrahepatic cholestasis despite having normal gamma-glutamyl transpeptidase levels. Acute and chronic liver diseases with viral, metabolic, and autoimmune etiology were excluded. Magnetic resonance imaging revealed normal intra- and extrahepatic bile ducts. A liver biopsy showed cholestasis in the centrilobular and intermediate zones and sinusoidal dilatation. Genetic testing revealed a homozygous c.3083&lowbar;3084delCAinsTG (Ala1028Val) mutation in the ABCB11 gene. The patient was treated with ursodeoxycholic acid 20 mg/kg/day and cholestyramine 4 g twice daily, and total bilirubin decreased to normal ranges after two months of therapy. This mutation (c.3083&lowbar;3084delCAinsTG) in the ABCB11 gene is the first reported in a patient with benign recurrent intrahepatic cholestasis type 2. [ABSTRACT FROM AUTHOR]

Benign recurrent intrahepatic cholestasis (BRIC) is an autosomal recessive cholestatic liver disease. Recurrent self-limited episodes of jaundice and severe pruritus are leading clinical manifestations. We report a 16-year-old Thai boy with three recurrent episodes of cholestasis. The first episode occurred at 30 months old. The subsequent recurrent episodes were at 13 and 16 years, respectively. Investigations including viral study, autoimmune hepatitis markers, abdominal ultrasound and magnetic resonance cholangiopancreatography (MRCP) were negative. Diagnosis of BRIC was made based on specific criteria. He was treated with cholestyramine and ursodeoxycholic acid when the first and second episodes occurred which resulted in good recovery. However, for the last recurrent episode, treatment with ursodeoxycholic acid failed to improve his condition, so his treatment was changed to rifampicin, which resulted in dramatic response. Although BRIC is a rare disease, it should be taken into account in all cases with recurrent cholestasis with normal or minimally elevated GGT level. Currently, genetic study for the mutation of ATP8B1 and ABCB11 genes are crucial for making a definite diagnosis.

Abstract: Background & Aims: Genetic defects causing dysfunction in bile salt export pump (BSEP/ABCB11) lead to liver diseases. ABCB11 mutations alter the bile acid metabolome. We asked whether profiling plasma bile acids could reveal compensatory mechanisms and track genetic and clinical status. Methods: We compared plasma bile acids in 17 ABCB11‐mutated patients, 35 healthy controls and 12 genetically undiagnosed cholestasis patients by ultra‐high‐performance liquid chromatography/multiple‐reaction monitoring‐mass spectrometry (UPLC/MRM‐MS). We developed an index to rank bile acid hydrophobicity, and thus toxicity, based on LC retention times. We recruited 42 genetically diagnosed hereditary cholestasis patients, of whom 12 were presumed to have impaired BSEP function but carried mutations in genes other than ABCB11, and 8 healthy controls, for further verification. Results: The overall hydrophobicity indices of total bile acids in both the ABCB11‐mutated group (11.89 ± 1.07 min) and the undiagnosed cholestasis group (11.46 ± 1.07 min) were lower than those of healthy controls (13.69 ± 0.77 min) (both p < 0.005). This was owing to increased bile acid modifications. Secondary bile acids were detected in patients without BSEP expression, suggesting biliary bile acid secretion through alternative routes. A diagnostic panel comprising lithocholic acid (LCA), tauro‐LCA, glyco‐LCA and hyocholic acid was identified that could differentiate the ABCB11‐mutated cohort from healthy controls and undiagnosed cholestasis patients (AUC=0.946, p < 0.0001) and, in non‐ABCB11‐mutated cholestasis patients, could distinguish BSEP dysfunction from normal BSEP function (9/12 vs 0/38, p < 0.0000001). Conclusions: Profiling of plasma bile acids has provided insights into cholestasis alleviation and may be useful for the clinical management of cholestatic diseases. [ABSTRACT FROM AUTHOR]

Aim: The aim of this study was to analyze the pathogenicity of rare/novel synonymous or intronic variants identified in ABCB11 heterozygotes presenting as progressive intrahepatic cholestasis with low γ‐glutamyltransferase. Methods: The enrolled variants were identified in ABCB11 between October 2009 and June 2016. The effects on pre‐RNA splicing were analyzed by in silico tools and minigene splicing assay. Results: There were three intronic (c.908 + 5G > A, c.2815‐8A > G, and c.612‐15_‐6del10bp) and two synonymous (c.1809G > A, p.K603 K and c.2418C > T, p.G806G) variants with unknown significance identified in ABCB11 of five ABCB11 heterozygotes. Parental studies were carried out for four patients, and revealed that the variants with unknown significance were compound heterozygous with other pathogenic variants. The five variants with unknown significance had minor allele frequency <0.1% or were absent from controls, and had positive prediction results by in silico tools. The effects on pre‐RNA splicing were further confirmed by minigene splicing assay. c.908 + 5A caused abnormal splicing in at least 78.5 ± 3.8% of products using a cryptic splice site (ss) 22 nucleotides (nt) upstream of the wild‐type (WT) 5′ss. Seven nucleotides of intron 22 upstream of the WT 3'ss was retained for all products from c.2815‐8G. c.612‐15_‐6del caused exon 8 skipping in 24.8 ± 7.7% of products, and 55 nt of exon 8 downstream of the WT 3′ss removal in remaining products. c.1809A led to exon 15 skipping. c.2418 T removed exon 20 and 62 nt of exon 21 downstream of the WT 3′ss by using a cryptic ss. Conclusions: We successfully identified five pathogenic synonymous or intronic variants with some common features. These features might help to choose the right variant for further functional assay. [ABSTRACT FROM AUTHOR]

Estradiol-17β-d-glucuronide (E17G), through the activation of different signaling proteins, induces acute endocytic internalization of canalicular transporters in rat, including multidrug resistance-associated protein 2 (Abcc2) and bile salt export pump (Abcb11), generating cholestasis. Insulin-like growth factor 1 receptor (IGF-1R) is a membrane-bound tyrosine kinase receptor that can potentially interact with proteins activated by E17G. The aim of this study was to analyze the potential role of IGF-1R in the effects of E17G in isolated perfused rat liver (IPRL) and isolated rat hepatocyte couplets. In vitro, IGF-1R inhibition by tyrphostin AG1024 (TYR, 100 nM), or its knock-down with siRNA, strongly prevented E17G-induced impairment of Abcc2 and Abcb11 function and localization. The protection by TYR was not additive to that produced by wortmannin (PI3K inhibitor, 100 nM), and both protections share the same dependency on microtubule integrity, suggesting that IGF-1R shared the signaling pathway of PI3K/Akt. Further analysis of the activation of Akt and IGF-1R induced by E17G indicated a sequence of activation GPR30-IGF-1R-PI3K/Akt. In IPRL, an intraportal injection of E17G triggered endocytosis of Abcc2 and Abcb11, and this was accompanied by a sustained decrease in the bile flow and the biliary excretion of Abcc2 and Abcb11 substrates. TYR did not prevent the initial decay, but it greatly accelerated the recovery to normality of these parameters and the reinsertion of transporters into the canalicular membrane. In conclusion, the activation of IGF-1R is a key factor in the alteration of canalicular transporter function and localization induced by E17G, and its activation follows that of GPR30 and precedes that of PI3K/Akt. [ABSTRACT FROM AUTHOR]

Background & Aims The bile salt export pump (BSEP, ABCB11 ), multidrug resistance protein 3 (MDR3, ABCB4 ) and the ATPase familial intrahepatic cholestasis 1 (FIC1, ATP8B1 ) mediate bile formation. This study aimed to determine the contribution of mutations and common variants in the FIC1, BSEP and MDR3 genes to cholestatic disorders of differing disease onset and severity. Methods Coding exons with flanking intron regions of ATP8B1 , ABCB11 , and ABCB4 were sequenced in cholestatic patients with assumed genetic cause. The effects of new variants were evaluated by bioinformatic tools and 3D protein modeling. Results In 427 patients with suspected inherited cholestasis, 149 patients carried at least one disease-causing mutation in FIC1, BSEP or MDR3, respectively. Overall, 154 different mutations were identified, of which 25 were novel. All 13 novel missense mutations were disease-causing according to bioinformatics analyses and homology modeling. Eighty-two percent of patients with at least one disease-causing mutation in either of the three genes were children. One or more common polymorphism(s) were found in FIC1 in 35.3%, BSEP in 64.3% and MDR3 in 72.6% of patients without disease-causing mutations in the respective gene. Minor allele frequencies of common polymorphisms in BSEP and MDR3 varied in our cohort compared to the general population, as described by gnomAD. However, differences in ethnic background may contribute to this effect. Conclusions In a large cohort of patients, 154 different variants were detected in FIC1, BSEP, and MDR3, 25 of which were novel. In our cohort, frequencies for risk alleles of BSEP (p.V444A) and MDR3 (p.I237I) polymorphisms were significantly overrepresented in patients without disease-causing mutation in the respective gene, indicating that these common variants can contribute to a cholestatic phenotype. Lay summary FIC1, BSEP, and MDR3 represent hepatobiliary transport proteins essential for bile formation. Genetic variants in these transporters underlie a broad spectrum of cholestatic liver diseases. To confirm a genetic contribution to the patients’ phenotypes, gene sequencing of these three major cholestasis-related genes was performed in 427 patients and revealed 154 different variants of which 25 have not been previously reported in a database. In patients without a disease-causing mutation, common genetic variants were detected in a high number of cases, indicating that these common variants may contribute to cholestasis development. [ABSTRACT FROM AUTHOR]

Background: Dubin-Johnson syndrome and intrahepatic cholestasis of pregnancy are rare chronic liver disorders. Dubin-Johnson syndrome may manifest as conjugated hyperbilirubinemia, darkly pigmented liver, presence of abnormal pigment in the parenchyma of hepatocytes and abnormal distribution of the coproporphyrin isomers I and III in the urine. Intrahepatic cholestatic jaundice of pregnancy presents as pruritus, abnormal liver biochemistry and increased serum bile acids. Case presentation: A Sri Lankan girl presented with recurrent episodes of jaundice. She had conjugated hyperbilirubinaemia with diffuse, coarse brown pigments in the hepatocytes. Urine coproporphyrin examination suggested Dubin-Johnson syndrome. Genetic studies confirmed missense homozygous variant p.Trp709Arg in the ATP-binding cassette sub-family C member 2 gene ABCC2 that encodes the Multidrug resistance-associated protein 2 that causes Dubin-Johnson syndrome. The gene study of the mother revealed the same missense variant in ABCC2/MRP2 but with a heterozygous status, and in addition a homozygous missense variant p.Val444Ala in the ATP-binding cassette, sub-family B member 11 gene ABCB11 that encodes the bile salt export pump. Conclusion: Dubin-Johnson syndrome should be considered when the common causes for conjugated hyperbilirubinaemia have been excluded, and patient has an increased percentage of direct bilirubin relative to total bilirubin concentration. Its early diagnosis prevents repeated hospital admissions and investigations. Knowledge of a well known homozygous variant in ABCB11 gene could help in the management of pregnancy. [ABSTRACT FROM AUTHOR]

Purpose: The goal of this study was the early diagnosis of ABCB11 spectrum liver disorders, especially those focused on benign recurrent intrahepatic cholestasis and progressive familial intrahepatic cholestasis. Methods: Fifty patients presenting neonatal cholestasis were evaluated to identify underlying etiologies. Genetic analysis was performed on patients suspected to have syndromic diseases or ABCB11 spectrum liver disorders. Two families with proven ABCB11 spectrum liver disorders were subjected to genetic analyses to confirm the diagnosis and were provided genetic counseling. Whole exome sequencing and Sanger sequencing were performed on the patients and the family members. Results: Idiopathic or viral hepatitis was diagnosed in 34%, metabolic disease in 20%, total parenteral nutrition induced cholestasis in 16%, extrahepatic biliary atresia in 14%, genetic disease in 10%, neonatal lupus in 2%, congenital syphilis in 2%, and choledochal cyst in 2% of the patients. The patient with progressive familial intrahepatic cholestasis had novel heterozygous mutations of ABCB11 c.11C>G (p.Ser4*) and c.1543A>G (p.Asn515Asp). The patient with benign recurrent intrahepatic cholestasis had homozygous mutations of ABCB11 c.1331T>C (p.Val444Ala) and heterozygous, c.3084A>G (p.Ala1028Ala). Genetic confirmation of ABCB11 spectrum liver disorder led to early liver transplantation in the progressive familial intrahepatic cholestasis patient. In addition, the atypically severe benign recurrent intrahepatic cholestasis patient was able to avoid unnecessary liver transplantation after genetic analysis. Conclusion: ABCB11 spectrum liver disorders can be clinically indistinguishable as they share similar characteristics related to acute episodes. A comprehensive genetic analysis will facilitate optimal diagnosis and treatment. [ABSTRACT FROM AUTHOR]

Progressive Familial Intrahepatic Cholestasis type 2 (PFIC2) is a rare cholestatic disorder diagnosed in infancy or childhood that can lead to severe hepatic fibrosis and liver failure. Mutations in the ABCB11 gene result in a deficiency of the bile salt export protein (BSEP) and accumulation of bile inside the hepatocytes. Hepatocellular carcinoma is another condition associated with severe forms of deletion mutations in the ABCB11 gene. Treatment options including ursodeoxycholic acid biliary diversion have mixed outcomes and some patients require liver transplantation. Here, we describe two siblings with an extremely mild form of PFIC2 inherited from heterozygous parents. The elder sibling had acute liver failure at the age of six months and both siblings had pruritus, cholestasis, coagulopathy and fat-soluble-vitamin deficiencies in infancy but have been asymptomatic past infancy. Genetic testing of the siblings revealed that each were compound heterozygotes for two missense mutations of the ABCB11 gene: p.C68Y and p.R832H. Medical treatment typical for PFIC2 has not been necessary for either patient. This is the first report of these variants following a mild course in two affected patients. [ABSTRACT FROM AUTHOR]

A self-organizing organoid model provides a new approach to study the mechanism of human liver organogenesis. Previous animal models documented that simultaneous paracrine signaling and cell-to- cell surface contact regulate hepatocyte differentiation. To dissect the relative contributions of the paracrine effects, we first established a liver organoid using human induced pluripotent stem cells (iPSCs), mesenchymal stem cells (MSCs) and human umbilical vein endothelial cells (HUVECs) as previously reported. Time-lapse imaging showed that hepatic-specified endoderm iPSCs (HE-iPSCs) self-assembled into three-dimensional organoids, resulting in hepatic gene induction. Progressive differentiation was demonstrated by hepatic protein production after in vivo organoid transplantation. To assess the paracrine contributions, we employed a Transwell system in which HE-iPSCs were separately co-cultured with MSCs and/or HUVECs. Although the three-dimensional structure did not form, their soluble factors induced a hepatocytelike phenotype in HE-iPSCs, resulting in the expression of bile salt export pump. In conclusion, the mesoderm-derived paracrine signals promote hepatocyte maturation in liver organoids, but organoid self-organization requires cell-to-cell surface contact. Our in vitro model demonstrates a novel approach to identify developmental paracrine signals regulating the differentiation of human hepatocytes. [ABSTRACT FROM AUTHOR]