Environmental Toxin Biliatresone-Induced Biliary Atresia-like Abnormal Cilia and Bile Duct Cell Development of Human Liver Organoids.

Biliary atresia (BA) is a poorly understood and devastating obstructive bile duct disease of newborns. Biliatresone, a plant toxin, causes BA-like syndrome in some animals, but its relevance in humans is unknown. To validate the hypothesis that biliatresone exposure is a plausible BA disease mechanism in humans, we treated normal human liver organoids with biliatresone and addressed its adverse effects on organoid development, functions and cellular organization. The control organoids (without biliatresone) were well expanded and much bigger than biliatresone-treated organoids. Expression of the cholangiocyte marker CK19 was reduced, while the hepatocyte marker HFN4A was significantly elevated in biliatresone-treated organoids. ZO-1 (a tight junction marker) immunoreactivity was localized at the apical intercellular junctions in control organoids, while it was markedly reduced in biliatresone-treated organoids. Cytoskeleton F-actin was localized at the apical surface of the control organoids, but it was ectopically expressed at the apical and basal sides in biliatresone-treated organoids. Cholangiocytes of control organoids possess primary cilia and elicit cilia mechanosensory function. The number of ciliated cholangiocytes was reduced, and cilia mechanosensory function was hampered in biliatresone-treated organoids. In conclusion, biliatresone induces morphological and developmental changes in human liver organoids resembling those of our previously reported BA organoids, suggesting that environmental toxins could contribute to BA pathogenesis.

Exome sequencing reveals a high genetic heterogeneity on familial Hirschsprung disease.

Hirschsprung disease (HSCR; OMIM 142623) is a developmental disorder characterized by aganglionosis along variable lengths of the distal gastrointestinal tract, which results in intestinal obstruction. Interactions among known HSCR genes and/or unknown disease susceptibility loci lead to variable severity of phenotype. Neither linkage nor genome-wide association studies have efficiently contributed to completely dissect the genetic pathways underlying this complex genetic disorder. We have performed whole exome sequencing of 16 HSCR patients from 8 unrelated families with SOLID platform. Variants shared by affected relatives were validated by Sanger sequencing. We searched for genes recurrently mutated across families. Only variations in the FAT3 gene were significantly enriched in five families. Within-family analysis identified compound heterozygotes for AHNAK and several genes (N = 23) with heterozygous variants that co-segregated with the phenotype. Network and pathway analyses facilitated the discovery of polygenic inheritance involving FAT3, HSCR known genes and their gene partners. Altogether, our approach has facilitated the detection of more than one damaging variant in biologically plausible genes that could jointly contribute to the phenotype. Our data may contribute to the understanding of the complex interactions that occur during enteric nervous system development and the etiopathology of familial HSCR.

Evaluation of a standardized protocol in the use of steroids after Kasai operation.

Although the Kasai operation is still the treatment of choice for infants with biliary atresia, the long-term success rate, as defined by survival without transplantation, is only about 25-40%. It has been proposed that post-operative inflammatory changes affect the bile flow and eventually lead to cholangitis and liver failure. Recent case reports have suggested that the administration of steroids post-operatively can improve outcomes. Since 2004, our unit has adopted a strict protocol for the use of post-operative steroids for patients who undergo Kasai operation. The aim of this study is to access the early outcomes of these patients. A retrospective analysis was carried out for all patients who received Kasai operation between 1996 and 2006. For the treatment group, patients all received prednisolone at 4 mg/kg 1 week after operation as guided by protocol. The demographics and outcomes, including post operative bilirubin level, episodes of cholangitic attack, the need for early liver transplantation (transplant within 1 year of Kasai), and transplantation-free survival, were noted. Statistical analysis was done using Fisher's exact test and unpaired t-test when appropriate. A value of P < 0.05 was considered to be statistically significant. Kasai operation was performed in 30 patients (11 boys and 19 girls) during the study period. Thirteen patients received post-operative prednisolone according to protocol. The average age at operation and the mean preoperative bilirubin levels for the steroid and non-steroid group were not significantly different. A normal post-operative bilirubin (defined as bilirubin level less than 20 mumol/L) was achieved at 6 months in 7 (53.9%) patients who received steroid and 8 (47.0%) patients who did not (P = 0.71). A statistically significant reduction in the post-operative bilirubin level was also seen at 3 and 6 months in the steroid group. Early liver transplantation was required in 5 (38.5%) patients with steroid and 5 (29.4%) patients without it (P = 0.60). No significant difference in terms of cholangitic attack was observed. There was also no steroid-associated complication reported. We conclude that lower post-operative bilirubin level can be achieved with the routine use of prednisolone. However, there is no statistical improvement in terms of early liver transplantation and cholangitis. This may be attributed to the small sample size of our study population. Based on this pilot study, a multi-centre randomized trial is needed.

Mutational analysis of SHH and GLI3 in anorectal malformations.

BACKGROUND: Anorectal malformations (congenital absence of the anal opening) are among the most common pediatric surgical problems and carry a significant chronic morbidity. METHODS: Direct sequencing was used to screen 88 anorectal malformations patients for mutations and polymorphisms in SHH and GLI3. These genes were chosen according to the phenotype presented by mutant mice and their expression patterns. RESULTS: We report on 10 GLI3 variants (IVS3+141C>G, T183A, IVS4+124T>C, IVS7+17G>A, IVS8+1 G>C, N503N, P941P, P998L, A1005A, A1039A) and four SHH mutation/variants (IVS1-49C>T, IVS2+111A>C, L214L, G290D). CONCLUSIONS: These variants are not over-represented in the healthy population and most are predicted to be benign. This study conveys the problematic assessment of the pathogenic role in disease of rare point mutations and variants.