Clinical and genetic features of congenital bile acid synthesis defect with a novel mutation in AKR1D1 gene sequencing: Case reports.

RATIONALE: Congenital bile acid synthesis defect (BASD) is a rare disease caused by mutations in the aldo-keto reductase 1D1 gene, which encodes the primary Δ4-3-oxosteroid 5ß-reductase enzyme. Early disease diagnosis is critical for early treatment with bile acid replacement therapy, with an excellent chance for recovery. In contrast, protracted diagnosis and treatment may lead to poor outcomes, including decompensated hepatic cirrhosis, liver transplant, and even death. PATIENT CONCERNS: Three clinical congenital bile acid synthesis defect cases in the Vietnamese population are herein reported. These pediatric patients presented with symptoms of prolonged postpartum jaundice and abnormal loose stool (mucus, lipids, and white). The clinical examinations showed hepatosplenomegaly. Urinalysis showed a very low fraction of primary bile acids and atypical 3-oxo-Δ4- bile acids in all three patients. DIAGNOSES: The patients were diagnosed with primary Δ4-3-oxosteroid 5ß-reductase deficiency. Next-generation gene sequencing revealed two homozygous mutations in the aldo-keto reductase family 1 member D1 gene. The first is a documented variant, c.797G>A (p.Arg266Gln), and the second is a novel mutation at c.155T>C (p.Ile52Thr). INTERVENTIONS: Immediately after diagnosis, patients were treated with oral chenodeoxycholate 5 mg/kg/d. OUTCOMES: The patients' symptoms, signs, and primary bile acids levels improved significantly. LESSONS: Clinicians should consider genetic disorders related to cholestasis for effective and life-saving treatment. A prompt genetic analysis by next-generation gene sequencing enables patients to access bile acid replacement therapy earlier, significantly improving short- and long-term outcomes.

Rotor Syndrome: Glucuronidated Bile Acidemia From Defective Reuptake by Hepatocytes.

Organic anion transporting polypeptide (OATP) 1B1 (gene, solute carrier organic anion transporter family member 1B1 [SLCO1B1]) and OATP1B3 (SLCO1B3) serve as transporters for hepatic uptake of important endogenous substances and several commonly prescribed drugs. Inactivation of both proteins together causes Rotor syndrome. How this OATP1B1/1B3 defect disturbs bile acid (BA) metabolism is largely unknown. In this study, we performed detailed BA analysis in 3 patients with genetically diagnosed Rotor syndrome. We found that BAs glucuronidated at the C-3 position (BA-3G) accounted for 50% or more of total BAs in these patients. In contrast but similarly to healthy controls, only trace amounts of BA-3G were detected in patients with constitutional indocyanine green excretory defect (OATP1B3 deficiency) or sodium-taurocholate cotransporting polypeptide (NTCP; gene, solute carrier family 10 member 1 [SLC10A1]) deficiency. Therefore, substantial amounts of BA-3G are synthesized in hepatocytes. The cycling pathway of BA-3G, consisting of excretion from upstream hepatocytes and uptake by downstream hepatocytes by OATP1B1/1B3 may exist to reduce the burden on upstream hepatocytes. Conclusion: Detailed BA analysis revealed glucuronidated bile acidemia in patients with Rotor syndrome. Further exploration of the physiologic role of glucuronidated BAs is necessary.

Modeling Human Bile Acid Transport and Synthesis in Stem Cell-Derived Hepatocytes with a Patient-Specific Mutation.

The bile salt export pump (BSEP) is responsible for the export of bile acid from hepatocytes. Impaired transcellular transport of bile acids in hepatocytes with mutations in BSEP causes cholestasis. Compensatory mechanisms to regulate the intracellular bile acid concentration in human hepatocytes with BSEP deficiency remain unclear. To define pathways that prevent cytotoxic accumulation of bile acid in hepatocytes, we developed a human induced pluripotent stem cell-based model of isogenic BSEP-deficient hepatocytes in a Transwell culture system. Induced hepatocytes (i-Heps) exhibited defects in the apical export of bile acids but maintained a low intracellular bile acid concentration by inducing basolateral export. Modeling the autoregulation of bile acids on hepatocytes, we found that BSEP-deficient i-Heps suppressed de novo bile acid synthesis using the FXR pathway via basolateral uptake and export without apical export. These observations inform the development of therapeutic targets to reduce the overall bile acid pool in patients with BSEP deficiency.

Changes in conjugated urinary bile acids across age groups.

Bile acid compositions are known to change dramatically after birth with aging. However, no reports have described the transition of conjugated urinary bile acids from the neonatal period to adulthood, and such findings would noninvasively offer insights into hepatic function. The aim of this study was to investigate differences in bile acid species, conjugation rates, and patterns, and to pool characteristics for age groups. We measured urinary bile acids in spot urine samples from 92 healthy individuals ranging from birth to 58 years old using liquid chromatography tandem mass spectrometry (LC/ESI-MS/MS). Sixty-six unconjugated and conjugated bile acids were systematically determined. After birth, urinary bile acids dramatically changed from fetal (i.e., Δ4-, Δ5-, and polyhydroxy-bile acids) to mature (i.e., CA and CDCA) bile acids. Peak bile acid excretion was 6-8 days after birth, steadily decreasing thereafter. A major change in bile acid conjugation pattern (taurine to glycine) also occurred at 2-4 months old. Our data provide important information regarding transitions of bile acid biosynthesis, including conjugation. The data also support the existence of physiologic cholestasis in the neonatal period and the establishment of the intestinal bacterial flora in infants.

The benefit of elobixibat in chronic constipation is associated with faecal deoxycholic acid but not effects of altered microbiota.

BACKGROUND: Elobixibat, a novel inhibitor of apical sodium-dependent bile acid transporter for treating chronic constipation, increases colonic bile acid concentrations, stimulating bowel function. However, it is not clear which bile acids are altered, or whether altered gut microbiota are associated with functional effects that may alter bowel function. AIMS: To investigate the effects of elobixibat on changes in the faecal concentrations of total and individual bile acids and in faecal microbiota. METHODS: This was a prospective, single-centre study. After baseline period, patients received 10 mg daily of elobixibat for 2 weeks. We evaluated the effects on bowel function, changes in faecal bile acid concentrations and composition of gut bacteria, before and after elobixibat administration. RESULTS: In the 30 patients analysed, the frequency of pre- and post-treatment bowel movements per fortnight was 7 and 10 (P < 0.001), respectively. The pre-treatment faecal bile acid concentration increased significantly from 10.9 to 15.0 µg/g stool post-treatment (P = 0.030), with a significant increase in faecal deoxycholic acid (pre-treatment 3.94 µg/g stool to post-treatment 5.02 µg/g stool, P = 0.036) and in glycine-conjugated deoxycholic and chenodeoxycholic acids. Shannon index was significantly decreased, but there were no significant changes at the genus and phylum levels. CONCLUSIONS: Short term treatment with elobixibat increased the concentrations of total bile acids and deoxycholic acid and decreased the diversity of faecal microbiota. The biological effects of elobixibat are associated with its effects on secretory bile acids, rather than the structural changes of an altered faecal microbiota.

Use of dried urine spots for screening of inborn errors of bile acid synthesis.

BACKGROUND: In pediatric patients with cholestasis of unknown cause, inborn errors of bile acid (BA) synthesis (IEBAS) may be considered. For the initial screening for IEBAS, clarification of the urine BA profile is essential. The transportation of urine in a frozen state via air delivery, however, is laborious and costly. This study assessed the feasibility of using dried urine spots (DUS) to establish a more convenient and affordable method of IEBAS screening. METHODS: We created DUS using urine samples from patients with 3ß-hydroxy-Δ5-C27-steroid dehydrogenase/isomerase deficiency (3ß-HSD) and Δ4-3-oxo-steroid 5ß-reductase deficiency as standard preparations. We started accepting DUS specimens by regular mail. RESULTS: The ratio of unusual to usual BA is essential for the initial detection of IEBAS, and the recovery rates of abnormal BA were acceptable. The recovery rate of Δ4-BA on day 28 decreased to 31.8% at 25°C, and to 19.6% at 37°C. Therefore, the sending of DUS should be avoided under conditions of high temperature. Of a total of 49 children with cholestasis, eight new patients were diagnosed with IEBAS using this screening method. CONCLUSION: The mailing screening system is expected to facilitate the shipment, from regions outside of Japan, of samples for IEBAS screening.

Genetic Analysis of Japanese Children With Acute Recurrent and Chronic Pancreatitis.

OBJECTIVES: Causes of acute recurrent pancreatitis (ARP) or chronic pancreatitis (CP) are sometimes difficult to determine in children. In such patients, genetic analysis may prove helpful. The present study analyzed mutations of cationic trypsinogen (PRSS1), serine protease inhibitor Kazal type 1 (SPINK1), chymotrypsin C (CTRC), and carboxypeptidase A1 (CPA1) and investigated the clinical features of children with these mutations. METHODS: Genetic analyses of mutations in these 4 genes were conducted in 128 patients with ARP or CP. Characteristics of the patients showing mutations were investigated using medical records. RESULTS: Fifty of the 128 (39.1%) subjects had at least 1 mutation (median age at onset, 7.6 years). Abdominal pain was the presenting symptom of pancreatitis in 48 of the 50 patients (96%). Fifteen of those 50 patients (30.0%) had a family history of pancreatitis. Gene mutations were present in PRSS1 in 26 patients, SPINK1 in 23, CTRC in 3, and CPA1 in 5. In the 31 patients with mutations in SPINK1, CTRC, or CPA1, 16 (51.6%) had homozygous or heterozygous mutations with other mutations. Three patients underwent surgery and another 4 patients underwent endoscopy to manage ARP or CP. Although 3 of the 7 patients complained of mild abdominal pain, none of those 7 patients experienced any obvious episode of ARP after treatment. CONCLUSIONS: In pediatric patients with idiopathic ARP and CP, genetic analysis is useful for identifying the cause of pancreatitis. Early endoscopic or surgical treatment prevents ARP by extending the interval between episodes of pancreatitis in this population.

Management of tacrolimus-associated food allergy after liver transplantation.

Increasingly, food allergy associated with tacrolimus after pediatric living-donor liver transplantation (LT) has been reported. Tacrolimus prevents the activation of T cells by blocking calcineurin, thus producing an immunosuppressive effect, but tacrolimus induces an imbalance in T-helper type 1 (Th1) and Th2 cells in the food allergy process. This report describes a case of tacrolimus-associated food allergy after pediatric living-donor LT. The patient was a 7-year-old Japanese girl who had undergone living-donor LT at 12 months of age, and whom we first saw in the clinic at age 18 months. She received immunosuppressive therapy by tacrolimus after transplantation. Atopic dermatitis developed in post-transplant month 18. Stridor, facial edema, lip swelling, and skin erythema after consuming tempura udon containing wheat occurred in post-transplant month 39, and she was subsequently diagnosed with anaphylactic shock. Eosinophilic leukocyte and serum immunoglobulin (Ig)E increased, and specific IgE was positive for some food allergens. Pharmacotherapy was therefore changed from tacrolimus to cyclosporine A, after which eosinophilic leukocyte and serum IgE decreased and atopic dermatitis improved.

Profile of bile acids in fetal gallbladder and meconium using liquid chromatography-tandem mass spectrometry.

BACKGROUND: The primary bile acids found in meconium vary with the gestational age of the fetus and the intestinal location of the meconium. We determined the composition of bile acids in samples that were collected from the gallbladder and intestine. METHODS: The bile-acid profiles of intestinal contents and the gallbladder were obtained from nine fetuses who died from abortion or respiratory failure within 72 h after birth. Intestinal content samples were collected from seven intestinal locations. The bile-acid profiles of meconium were also obtained from seven full-term live births for comparison. The profiles were analyzed using liquid chromatography-tandem mass spectrometry. RESULTS: The bile acids in meconium collected from stillborn and live births were mainly chenodeoxycholic acid and cholic acid, conjugated with taurine, glycine, and sulfate. The same bile acids were found in the gallbladder, except that sulfate was not found. CONCLUSIONS: Sulfate-conjugated bile acid is found in urine, but rarely in stool. In this study, the gallbladder bile acid contained no sulfate conjugates, but these were present in intestinal contents and meconium. These results indicate that sulfate-conjugated bile acids are not excreted into the intestine through the biliary tract but originate from swallowed amniotic fluid that contains fetal urine.

Scoring system for the prediction of severe acute pancreatitis in children.

BACKGROUND: The lack of an accurate scoring system for pediatric acute pancreatitis could cause delays in appropriate clinical management and increase the risk of progressive life-threatening complications. We investigated a modified Ministry of Health, Labour and Welfare of Japan (JPN) scoring system that uses pediatric systemic inflammatory response syndrome (SIRS) score, age, and weight to establish a more useful scoring system for children. METHODS: A retrospective chart review was conducted of pediatric patients with acute pancreatitis who were admitted to Juntendo University Hospital between 1985 and 2011. The sensitivity, specificity, and positive and negative predictive values of the pediatric JPN scoring system were calculated and then compared with those of previously developed scoring systems. RESULTS: The patient group consisted of 145 patients (88 girls, 57 boys). The pediatric JPN score had greater sensitivity (80%) than the Ranson (60%), modified Glasgow (50%), and DeBanto (60%) scores. The specificity was 96% for the pediatric JPN score, 94% for the Ranson score, 99% for the modified Glasgow score, and 86% for the DeBanto score. CONCLUSION: The pediatric JPN score can be used to predict severe acute pancreatitis during the initial medical assessment.

Prophylaxis for ribavirin-related anemia using eicosapentaenoic acid in chronic hepatitis C patients.

BACKGROUND: Ribavirin-related anemia is a serious side-effect of the pegylated interferon and ribavirin therapy used for hepatitis C, and may be cause for a reduction in ribavirin dose or even cessation of treatment. The aim of this study was to evaluate the prophylactic effects of oral eicosapentaenoic acid (EPA) supplementation on ribavirin-induced hemolytic anemia in pediatric and young adult patients. METHODS: Twelve chronic hepatitis C patients ranging in age from 3 to 21 years (mean, 13.9 ± 5.1 years) who received pegylated interferon α-2b and ribavirin combination therapy were randomized to either the control group (n = 6) or EPA group (n = 6). Blood samples were collected before, and at 4, 8, and 16 weeks after treatment to measure clinical laboratory parameters. RESULTS: The reduction in hemoglobin levels of the EPA group was significantly ameliorated at 8 and 16 weeks when compared to the control group (P < 0.05). There was no significant difference in plasma ribavirin concentrations between the two groups during the treatment. However, one patient in the control group had a reduction in ribavirin dose. CONCLUSION: EPA supplementation prevented ribavirin-induced hemolytic anemia during combination therapy with pegylated interferon α-2b and ribavirin in pediatric and young adult patients.