Genetic variability of interleukin 4 gene in Taiwanese children with biliary atresia

Factors Determining Bone Mineral Density in Patients with Biliary Atresia after a Successful Kasai Operation

BACKGROUND

Hepatic osteodystrophy is a common complication in patients with chronic liver disease, however, bone mineral status in patients with biliary atresia has rarely been investigated.

METHODS

Twenty-nine children with biliary atresia were enrolled in our study and their demographic data, bone mineral density (BMD) of lumbar spine and bilateral femoral neck, and biochemical parameters were measured and analyzed.

RESULTS

The majority of our patients had osteopenia or osteoporosis over at least one part of the skeleton although none had jaundice. Instead of T helper 1 cell cytokine, interleukin (IL)-4 had a significant negative correlation with BMD of the right femoral neck (β = -0.251, p = 0.027) and left femoral neck (β = -0.299, p = 0.012) independently by multiple linear regression analysis.

CONCLUSION

We conclude that chronic inflammation with increased expression of IL-4 may be an important factor for compromised bone health in patients with biliary atresia.

Association Between IL-4 Polymorphisms and Risk of Liver Disease: An Updated Meta-Analysis

Interleukin-4 (IL-4) polymorphisms have been reported to influence an individual's susceptibility to liver disease as it is a central anti-inflammatory Th2 cytokine; however, these results remain controversial.A comprehensive meta-analysis of the relevant literature was thus performed to better estimate the relationship between IL-4 polymorphisms and liver disease.Systematic searches of various databases (PubMed, Embase, Cochrane Library, and China National Knowledge Infrastructure) for studies published before July 5, 2015 were performed. Odds ratios (ORs) with 95% confidence intervals (CIs) calculated in fixed or random-effects models were used to estimate the strength of the association. Subgroup analyses, meta-regression, Galbraith plots, and sensitivity analyses were also performed.A total of 16 case-control studies, of which 15 involved the -590C/T polymorphism and 3 involved the -33T/C polymorphism, were included in the study. With respect to the -590C/T polymorphism, a significantly increased risk of liver diseases was found in the overall population (TT + CT vs CC: OR = 1.25, 95% CI = 1.06-1.49, P = 0.009 and CT vs CC: OR = 1.22, 95% CI = 1.00-1.48, P = 0.048) and the Asian population (TT + CT vs CC: OR = 1.28, 95% CI = 1.04-1.57, P = 0.020). Further subgroup analyses also showed significant associations between the -590C > T polymorphism and the risk of hepatitis C infection and hepatocellular carcinoma. However, no association was found between the -33T/C polymorphism and risk of liver diseases in all comparison models.This meta-analysis suggested that the IL-4 -590C > T polymorphism is associated with an increased risk of hepatitis C infection and hepatocellular carcinoma, especially among the Asian population.

Evidence from human and zebrafish that GPC1 is a biliary atresia susceptibility gene

BACKGROUND & AIMS

Biliary atresia (BA) is a progressive fibroinflammatory disorder of infants involving the extrahepatic and intrahepatic biliary tree. Its etiology is unclear but is believed to involve exposure of a genetically susceptible individual to certain environmental factors. BA occurs exclusively in the neonatal liver, so variants of genes expressed during hepatobiliary development could affect susceptibility. Genome-wide association studies previously identified a potential region of interest at 2q37. We continued these studies to narrow the region and identify BA susceptibility genes.

METHODS

We searched for copy number variants that were increased among patients with BA (n = 61) compared with healthy individuals (controls; n = 5088). After identifying a candidate gene, we investigated expression patterns of orthologues in zebrafish liver and the effects of reducing expression, with morpholino antisense oligonucleotides, on biliary development, gene expression, and signal transduction.

RESULTS

We observed a statistically significant increase in deletions at 2q37.3 in patients with BA that resulted in deletion of one copy of GPC1, which encodes glypican 1, a heparan sulfate proteoglycan that regulates Hedgehog signaling and inflammation. Knockdown of gpc1 in zebrafish led to developmental biliary defects. Exposure of the gpc1 morphants to cyclopamine, a Hedgehog antagonist, partially rescued the gpc1-knockdown phenotype. Injection of zebrafish with recombinant Sonic Hedgehog led to biliary defects similar to those of the gpc1 morphants. Liver samples from patients with BA had reduced levels of apical GPC1 in cholangiocytes compared with samples from controls.

CONCLUSIONS

Based on genetic analysis of patients with BA and zebrafish, GPC1 appears to be a BA susceptibility gene. These findings also support a role for Hedgehog signaling in the pathogenesis of BA.

Participation of natural killer cells in the pathogenesis of bile duct lesions in biliary atresia

Aims

Immunological disturbances including innate immunity after a suspected viral infection are considered important to the pathogenesis of bile duct lesions in cases of biliary atresia (BA). In this study, we tried to evaluate whether natural killer (NK) cells and CX3CL1 (Fractalkine) and its receptor (CX3CR1) are involved in the bile duct injury.

Methods

Using the section of BA (22 cases) and controls, immunohistochemistry for CD56, CD16, CD68, CX3CL1 and CX3CR1 was performed. Moreover, using cultured biliary epithelial cells (BECs) and NK cells, the production of CX3CL1 in BECs and the migration of NK cells were evaluated.

Results

It was found that CD56(−)CD16(+)CD68(−) NK cells were increased around the damaged small and large bile ducts in BA and hepatitis C virus-related chronic hepatitis in comparison with other controls. CX3CL1 was strongly expressed on the damaged bile ducts in BA, while this expression was relatively weak or absent in the bile ducts of normal liver. The results suggest the CD56(−)CD16(+) NK cells to be involved in the development of bile duct injuries in BA. These CD16(+) NK cells were positive for CX3CR1, and attracted by CX3CL1 expressed on bile ducts. Further study revealed that stimulation with poly(I:C) (a synthetic analogue of viral dsRNA) increased the expression of CX3CL1 on cultured BECs followed by increased migrational activity of cultured NK cells.

Conclusions

CD56(−)CD16(+) NK cells with reduced NK activity may be involved in the bile duct damage in BA, and CD16(+) NK cells expressing CX3CR1 may be attracted by and interact with bile ducts expressing CX3CL1.