Gut microbial profile in biliary atresia: a case-control study

Biliary fibrosis is an important but neglected pathological feature in hepatobiliary disorders: from molecular mechanisms to clinical implications

Fibrosis resulting from pathological repair secondary to recurrent or persistent tissue damage often leads to organ failure and mortality. Biliary fibrosis is a crucial but easily neglected pathological feature in hepatobiliary disorders, which may promote the development and progression of benign and malignant biliary diseases through pathological healing mechanisms secondary to biliary tract injuries. Elucidating the etiology and pathogenesis of biliary fibrosis is beneficial to the prevention and treatment of biliary diseases. In this review, we emphasized the importance of biliary fibrosis in cholangiopathies and summarized the clinical manifestations, epidemiology, and aberrant cellular composition involving the biliary ductules, cholangiocytes, immune system, fibroblasts, and the microbiome. We also focused on pivotal signaling pathways and offered insights into ongoing clinical trials and proposing a strategic approach for managing biliary fibrosis-related cholangiopathies. This review will offer a comprehensive perspective on biliary fibrosis and provide an important reference for future mechanism research and innovative therapy to prevent or reverse fibrosis.

Biliary atresia: the role of gut microbiome, and microbial metabolites

Biliary atresia (BA) is a progressive fibroinflammatory disease affecting both the extrahepatic and intrahepatic bile ducts, potentially leading to chronic cholestasis and biliary cirrhosis. Despite its prevalence, the exact mechanisms behind BA development remain incompletely understood. Recent research suggests that the gut microbiota and its metabolites may play significant roles in BA development. This paper offers a comprehensive review of the changing characteristics of gut microbiota and their metabolites at different stages of BA in children. It discusses their influence on the host's inflammatory response, immune system, and bile acid metabolism. The review also explores the potential of gut microbiota and metabolites as a therapeutic target for BA, with interventions like butyrate and gut microbiota preparations showing promise in alleviating BA symptoms. While progress has been made, further research is necessary to untangle the complex interactions between gut microbiota and BA, paving the way for more effective prevention and treatment strategies for this challenging condition.

The gut microbiota-bile acid axis in cholestatic liver disease

Cholestatic liver diseases (CLD) are characterized by impaired normal bile flow, culminating in excessive accumulation of toxic bile acids. The majority of patients with CLD ultimately progress to liver cirrhosis and hepatic failure, necessitating liver transplantation due to the lack of effective treatment. Recent investigations have underscored the pivotal role of the gut microbiota-bile acid axis in the progression of hepatic fibrosis via various pathways. The obstruction of bile drainage can induce gut microbiota dysbiosis and disrupt the intestinal mucosal barrier, leading to bacteria translocation. The microbial translocation activates the immune response and promotes liver fibrosis progression. The identification of therapeutic targets for modulating the gut microbiota-bile acid axis represents a promising strategy to ameliorate or perhaps reverse liver fibrosis in CLD. This review focuses on the mechanisms in the gut microbiota-bile acids axis in CLD and highlights potential therapeutic targets, aiming to lay a foundation for innovative treatment approaches.

Biliary atresia

Biliary atresia (BA) is a progressive inflammatory fibrosclerosing disease of the biliary system and a major cause of neonatal cholestasis. It affects 1:5,000-20,000 live births, with the highest incidence in Asia. The pathogenesis is still unknown, but emerging research suggests a role for ciliary dysfunction, redox stress and hypoxia. The study of the underlying mechanisms can be conceptualized along the likely prenatal timing of an initial insult and the distinction between the injury and prenatal and postnatal responses to injury. Although still speculative, these emerging concepts, new diagnostic tools and early diagnosis might enable neoadjuvant therapy (possibly aimed at oxidative stress) before a Kasai portoenterostomy (KPE). This is particularly important, as timely KPE restores bile flow in only 50-75% of patients of whom many subsequently develop cholangitis, portal hypertension and progressive fibrosis; 60-75% of patients require liver transplantation by the age of 18 years. Early diagnosis, multidisciplinary management, centralization of surgery and optimized interventions for complications after KPE lead to better survival. Postoperative corticosteroid use has shown benefits, whereas the role of other adjuvant therapies remains to be evaluated. Continued research to better understand disease mechanisms is necessary to develop innovative treatments, including adjuvant therapies targeting the immune response, regenerative medicine approaches and new clinical tests to improve patient outcomes.

Gut Bifidobacterium longum is associated with better native liver survival in patients with biliary atresia

Background & Aims

The gut microbiome plays an important role in liver diseases, but its specific impact on biliary atresia (BA) remains to be explored. We aimed to investigate the microbial signature in the early life of patients with BA and to analyze its influence on long-term outcomes.

Methods

Fecal samples (n = 42) were collected from infants with BA before and after Kasai portoenterostomy (KPE). The stool microbiota was analyzed using 16S rRNA next-generation sequencing and compared with that of age-matched healthy controls (HCs). Shotgun metagenomic sequencing analysis was employed to confirm the bacterial composition in 10 fecal samples before KPE. The correlation of the microbiome signature with liver function and long-term outcomes was assessed.

Results

In the 16S rRNA next-generation sequencing analysis of fecal microbiota, the alpha and beta diversity analyses revealed significant differences between HCs and patients with BA before and after KPE. The difference in microbial composition analyzed by linear discriminant analysis and random forest classification revealed that the abundance of Bifidobacterium longum (B. longum) was significantly lower in patients before and after KPE than in HCs. The abundance of B. longum was negatively correlated with the gamma-glutamyltransferase level after KPE (p <0.05). Patients with early detectable B. longum had significantly lower total and direct bilirubin 3 months after KPE (p <0.005) and had a significantly lower liver transplantation rate (hazard ratio: 0.16, 95% CI 0.03-0.83, p = 0.029). Shotgun metagenomic sequencing also revealed that patients with BA and detectable B. longum had reduced total and direct bilirubin after KPE.

Conclusion

The gut microbiome of patients with BA differed from that of HCs, with a notable abundance of B. longum in early infancy correlating with better long-term outcomes.

Impact and implications

Bifidobacterium longum (B. longum) is a beneficial bacterium commonly found in the human gut. It has been studied for its potential impacts on various health conditions. In patients with biliary atresia, we found that a greater abundance of B. longum in the fecal microbiome is associated with improved clinical outcomes. This suggests that early colonization and increasing B. longum levels in the gut could be a therapeutic strategy to improve the prognosis of patients with biliary atresia.

Analysis of gut microecological characteristics and differences between children with biliary atresia and non-biliary atresia in infantile cholestasis

Introduction

In infants with cholestasis, variations in the enterohepatic circulation of bile acids and the gut microbiota (GM) characteristics differ between those with biliary atresia (BA) and non-BA, prompting a differential analysis of their respective GM profiles.

Methods

Using 16S rDNA gene sequencing to analyse the variance in GM composition among three groups: infants with BA (BA group, n=26), non-BA cholestasis (IC group, n=37), and healthy infants (control group, n=50). Additionally, correlation analysis was conducted between GM and liver function-related indicators.

Results

Principal component analysis using Bray-Curtis distance measurement revealed a significant distinction between microbial samples in the IC group compared to the two other groups. IC-accumulated co-abundance groups exhibited positive correlations with aspartate aminotransferase, alanine aminotransferase, total bilirubin, direct bilirubin, and total bile acid serum levels. These correlations were notably reinforced upon the exclusion of microbial samples from children with BA.

Conclusion

The varying "enterohepatic circulation" status of bile acids in children with BA and non-BA cholestasis contributes to distinct GM structures and functions. This divergence underscores the potential for targeted GM interventions tailored to the specific aetiologies of cholestasis.

Chronic Liver Disease - What's New?

Chronic liver disease (CLD) is a persistent public health burden, with over one billion cases reported worldwide. In most cases, the progression of CLD is slow and undulating with end-stage liver disease developing at variable time points depending on the underlying etiology of the disease. The concept of reversibility or halting progression to end stage liver disease is recent and various medications are in the pipeline which influence the progression of CLD. Non-invasive tests for monitoring of CLD may have the potential to avoid the morbidity and mortality related to invasive procedures. However, their applicability and validation in pediatrics requires further development and a coordinated effort by large pediatric liver centres. Recent advances in metabolomics and modern molecular technologies have led to an understanding of the interaction between gut microbiome liver axis and gut dysbiosis contributing to liver diseases. In the future, modifying the gut microbiome has the potential to change the outcome and significantly reduce the morbidity associated with CLD. This article focuses on newer modalities and concepts in the management of CLD, which may help develop strategies to prevent its progression to end-stage liver disease and associated morbidity/mortality.

Alterations of gut microbiota in infants with biliary atresia identified by 16S rRNA-sequencing

BACKGROUND

Biliary atresia (BA) is a severe neonatal disease with progressive intra- and extra-hepatic bile ducts inflammation and hepatic fibrosis. Characterization of gut microbiome profiles in infants with biliary atresia can provide valuable information and potential disease biomarkers. Our study aims to explore the relationship between gut microbiota and biliary atresia.

METHODS

16 S ribosomal RNA (rRNA) gene sequencing was carried out to identify the differences in composition and diversity of gut microbiota between infants with BA and healthy subjects. A total of 31 infants with biliary atresia and 20 healthy subjects were recruited.

RESULTS

The composition of gut microbiota in BA group was significantly different with the normal control group (P < 0.05) and the abundance ratio of Klebsiella/Bifidobacterium showed great potential for identification of BA (P < 0.01). In addition, the differential bacterial taxa were involved in lipid and vitamins metabolism.

CONCLUSION

Our results could provide potential non-invasive biomarker for identification of biliary atresia and contribute to the treatment in terms of ameliorating microbiota dysbiosis.

Diagnostic and prognostic value of the gut microbiota and its metabolite butyrate in children with biliary atresia

PURPOSE

To determine the prevalent microbiological profile of biliary atresia (BA) patients at the time of its occurrence by studying their intestinal flora.

METHODS

A total of 118 gut microbiota samples from three groups of 43 BA patients, 33 disease controls (DC) with other cholestatic diseases and 42 healthy controls (HC), were analyzed by deep mining of public data. Subsequently, a total of 23 fecal samples from three groups of clinically collected patients (11 BA, 6 DC and 6 HC) were sequenced for 16S rRNA gene amplification and analyzed for serum butyrate (BU) level by liquid chromatography.

RESULTS

Taxonomic analysis revealed significant differences in the composition of the intestinal microbiota between BA patients and controls, with a reduction in diversity and a higher abundance of Proteobacteria, Streptococcus and Lactobacillus in the BA group. Database and clinical data analyses concluded that Streptococcus/Bacteroides (AUC = 0.9035, 95% CI 0.8347-0.9722, P < 0.0001) or Streptococcus/Eggerthella (AUC = 0.8333, 95% CI 0.6340-1.000, P = 0.027) was the best microbiota to differentiate between BA and DC. Serum butyrate levels were low in the BA and DC groups and differed from the HC group (P = 0.01, P = 0.04). Butyrate levels in BA were negatively correlated with jaundice clearance and cholangitis, but not statistically significant.

CONCLUSIONS

Our study reveals changes in the composition of the gut microbiota in BA, especially the butyrate-producing microbiota, and suggests the potential for using gut microbiota as a noninvasive diagnostic benefit for BA. Low levels of serum butyrate in BA may indicate a poor prognosis.

Severity assessment to guide empiric antibiotic therapy for cholangitis in children after Kasai portoenterostomy: a multicenter prospective randomized control trial in China

BACKGROUND

Cholangitis is common in patients with biliary atresia following Kasai portoenterostomy (KPE). The prompt use of empiric antibiotics is essential due to the lack of identified microorganisms. The authors aimed to validate a severity grading system to guide empiric antibiotic therapy in the management of post-KPE cholangitis.

MATERIALS AND METHODS

This multicenter, prospective, randomized, open-label study recruited patients with post-KPE cholangitis and was conducted from January 2018 to December 2019. On admission, patients were categorized into mild, moderate, and severe cholangitis according to the severity grading system. Patients in the mild cholangitis group were randomized to receive cefoperazone sodium tazobactam sodium (CSTS) or meropenem (MEPM). Patients with severe cholangitis were randomized to treatment with MEPM or a combination of MEPM plus immunoglobulin (MEPM+IVIG). Patients with moderate cholangitis received MEPM.

RESULTS

The primary endpoint was duration of fever (DOF). Secondary outcomes included blood culture, length of hospital stay, incidence of recurrent cholangitis, jaundice clearance rate, and native liver survival (NLS). For mild cholangitis, DOF, and length of hospital stay were similar between those treated with CSTS or MEPM (all P >0.05). In addition, no significant difference in recurrence rate, jaundice clearance rate, and NLS was observed between patients treated with CSTS and MEPM at 1-month, 3-month, and 6-month follow-up. In patients with moderate cholangitis, the DOF was 36.00 (interquartile range: 24.00-48.00) h. In severe cholangitis, compared with MEPM, MEPM+IVIG decreased DOF and improved liver function by reducing alanine aminotransferase, aspartate aminotransferase, gamma-glutamyl transferase, and direct bilirubin at 1-month follow-up. However, recurrence rate, jaundice clearance rate, and NLS did not differ significantly between MEPM+IVIG and MEPM at 1-month, 3-month, and 6-month follow-up.

CONCLUSIONS

In patients with post-KPE cholangitis, MEPM is not superior to CSTS for the treatment of mild cholangitis. However, MEPM+IVIG treatment was associated with better short-term clinical outcomes in patients with severe cholangitis.

A novel gut microbiome-immune axis influencing pathology in HCMV infected infants with neonatal cholestasis

The interplay of active HCMV infection with gut dysbiosis in the immunopathology of cholestasis in neonates and infants remains unexplored. In this study, we evaluated gut microbiome profiles and immune dysfunction in a cohort of HCMV infected cholestatic infants (IgM positive, N = 21; IgM negative, N = 25) compared to healthy infants, N = 10. HCMV infected IgM positive individuals exhibited increased clinical severity in terms of liver dysfunction, altered CD4+: CD8+ ratio, and elevated Granzyme B levels in cellular immune subsets. Gut microbiome analysis revealed distinct and differential diversity and composition within infected groups aligned with clinical severity reflected through the increased abundance of Gammaproteobacteria, reduced Bifidobacteria, and a unique signature mapping to the HCMV infected IgM negative group. Correlation analyses revealed associations between Bifidobacterium breve, Gammaproteobacteria, Firmicutes, Clostridia, Finegoldia magna, Veillonella dispar, and Granzyme B expressing immune cell subsets. Our study describes a novel gut microbiome-immune axis that may influence disease severity in cholestatic infants with active HCMV infection.

Customized Postoperative Therapy Improves Bile Drainage in Biliary Atresia: A Single Center Preliminary Report

BACKGROUND

Controversies in management of biliary atresia (BA) after hepatoportoenterostomy (HPE) lead to variable treatment protocols. We implemented standardized medical management after HPE, customizing the use of antibiotics and corticosteroids based on patient-specific factors.

METHODS

In this retrospective analysis, 20 consecutive infants underwent HPE for BA and were compared to a historical cohort. Analysis of successful biliary drainage 3 months after HPE (defined as serum total bilirubin <2 mg/dL) was the primary endpoint; survival with native liver at 2 years was the secondary endpoint.

RESULTS

Sixteen of 20 (80%) infants had successful bile drainage, compared to 8 of 20 (40%) infants in the historical cohort (P = 0.0225). Sixteen of 20 patients in the new protocol have reached 2 years of age or required liver transplantation. Among the sixteen, 11 (68.8%) are alive with native livers versus 10 of 20 (50%) in the historical cohort (P = 0.0970).

CONCLUSION

This preliminary report suggests the potential benefit of tailored use of postoperative antibiotics and corticosteroids in improving biliary drainage after HPE.

LEVEL OF EVIDENCE

III.

Percutaneous transhepatic cholangial drainage or antibiotic therapy worsens response to immunotherapy in advanced cholangiocarcinoma

BACKGROUND

Bile duct obstruction is a common issue for patients with advanced cholangiocarcinoma (CCA). Percutaneous transhepatic cholangial drainage (PTCD) is often required to relieve the obstruction. However, PTCD may alter the intestinal microbiota, which can affect the efficacy of immunotherapy. Antibiotics (ATB) can also have significant immunomodulatory effects by perturbing the gut microbiota. Therefore, this study aimed to investigate whether PTCD or ATB therapy is associated with overall survival (OS) or progression-free survival (PFS) in patients with advanced CCA receiving first-line chemotherapy plus immune checkpoint blockade (ICB) in clinical practice. We also explored whether the gut microbiota changes after receiving PTCD.

METHODS

We conducted a single-center retrospective analysis of PTCD and ATB therapy in patients with advanced CCA. PTCD was performed before ICB initiation, and ATB was administered within 1 month before and 6 weeks after ICB initiation. Our primary outcomes were PFS and OS. Moreover, we used 16s rRNA sequencing to analyze fecal and bile samples obtained from patients who underwent PTCD.

RESULTS

In total, 107 patients with CCA were included. Among patients who did not undergo PTCD, ICB plus chemotherapy significantly improved OS vs. chemotherapy alone (hazard ratio [HR] 0.21, 95% confidence interval [CI] 0.09-0.45, p < 0.0001). PFS was also significantly improved in patients who received ICB plus chemotherapy compared with chemotherapy alone (HR 0.36, 95% CI 0.16-0.80, p = 0.0024). However, ICB plus chemotherapy did not improve survival compared with chemotherapy alone among patients who received PTCD. Overall changes in the fecal microbiota of patients after PTCD involved significant reductions in which Escherichia - Shigella.

CONCLUSIONS

The use of ATB or PTCD in patients with CCA receiving ICB was associated with worse OS compared with chemotherapy alone, and PTCD affects the gut microbiota. Escherichia - Shigella was significantly reduced in feces of patients after PTCD.

The influence of liver transplantation on the interplay between gut microbiome and bile acid homeostasis in children with biliary atresia

BACKGROUND

Biliary atresia (BA) causes neonatal cholestasis and rapidly progresses into cirrhosis if left untreated. Kasai portoenterostomy may delay cirrhosis. BA remains among the most common indications for liver transplantation (LT) during childhood. Liver function and gut microbiome are interconnected. Disturbed liver function and enterohepatic signaling influence microbial diversity. We, herein, investigate the impact of LT and reestablishment of bile flow on gut microbiome-bile acid homeostasis in children with BA before (pre, n = 10), 3 months (post3m, n = 12), 12 months (post12m, n = 9), and more than 24 months (post24 + m, n = 12) after LT.

METHODS

We analyzed the intestinal microbiome of BA patients before and after LT by 16S-rRNA-sequencing and bioinformatics analyses, and serum primary and secondary bile acid levels.

RESULTS

The gut microbiome in BA patients exhibits a markedly reduced alpha diversity in pre (p = 0.015) and post3m group (p = 0.044), and approximated healthy control groups at later timepoints post12m (p = 1.0) and post24 + m (p = 0.74). Beta diversity analysis showed overall community structure similarities of pre and post3m (p = 0.675), but both differed from the post24 + m (p < 0.001). Longitudinal analysis of the composition of the gut microbiome revealed the Klebsiella genus to show increased abundance in the post24 + m group compared with an age-matched control (p = 0.029). Secondary bile acid production increased 2+ years after LT (p = 0.03). Multivariable associations of microbial communities and clinical metadata reveal several significant associations of microbial genera with tacrolimus and mycophenolate mofetil-based immunosuppressive regimens.

CONCLUSIONS

In children with BA, the gut microbiome shows strongly reduced diversity before and shortly after LT, and approximates healthy controls at later timepoints. Changes in diversity correlate with altered secondary bile acid synthesis at 2+ years and with the selection of different immunosuppressants.

Biliatresone: progress in biliary atresia study

BACKGROUND

Biliary atresia (BA) is one of the main causes of neonatal end-stage liver disease. Without timely diagnosis and treatment, most children with BA will develop irreversible liver fibrosis within the first two months. While current theorized causes of BA include viral infection, immune disorders, and genetic defects, the comprehensive etiology is still largely unknown. Recently, biliatresone attracted much interest for its ability to induce BA in both zebrafish and mice, so we summarized the latest progress of biliatresone research in BA and tried to answer the question of whether it could provide further clues to the etiology of human BA.

DATA SOURCES

We conducted a PubMed search for any published articles related to the topic using search terms including "biliary atresia", "biliatresone", "GSH", and "HSP90". Relevant data were extracted from the original text or supplementary materials of the corresponding articles.

RESULTS

Biliatresone had shown its unique toxicity in multiple species such as zebrafish and mice, and pathogenic factors involved included glutathione (GSH), heat shock protein 90 (HSP90) and the related pathways. In combination with epidemiological evidence and recent studies on the intestinal flora in biliary atresia, a new pathogenic hypothesis that the occurrence of biliary atresia is partly due to biliatresone or its structure-like compounds depositing in human body via vegetables or/and the altered intestinal flora structure can be tentatively established.

CONCLUSIONS

Based on the existing evidence, we emphasized that GSH and HSP90 are involved in the development of BA, and the maternal diet, especially higher vegetable intake of Asian women of childbearing age, accompanied by the altered intestinal flora structure, may contribute to the occurrence of biliary atresia and the higher incidence in the Asia group. However, the evidence from large sample epidemiological research is necessary.

Saliva microbiome alterations in dental fluorosis population

Background

We aimed to explore saliva microbiome alterations in dental fluorosis population.

Methods

The prevalence of dental fluorosis was examined in 957 college students. Dean's fluorosis index was used to evaluate the dental fluorosis status. Changes in the composition of the salivary microbiome were assessed in a subset of these patients (100 healthy controls, 100 dental fluorosis patients).

Results

Dental fluorosis affected 47% of the student sample, and incidence was unrelated to gender. Compared with healthy controls, the microbiota of patients with dental fluorosis exhibited increased diversity, with increased abundance of Treponema lecithinolyticum, Vibrio metschnikovii, Cupriavidus pauculus, Pseudomonas, Pseudomonadaceae, Pseudomonadales, and decreased abundance of Streptococcus mutans, Streptococcus sanguinis, Gemella, and Staphylococcales. Function analyses showed increases in arginine biosynthesis in patients affected by dental fluorosis, together with reductions in amino sugar and nucleotide sugar metabolism, fructose and mannose metabolism, and starch and sucrose metabolism.

Conclusions

These results suggest that there are striking differences in salivary microbiome between healthy controls and dental fluorosis patients. Dental fluorosis may contribute to periodontitis and systemic lung diseases. There is a need for cohort studies to determine whether altering the salivary microbiota in dental fluorosis patients can alter the development of oral or systemic diseases.

The Gut-Liver Axis in Pediatric Liver Health and Disease

There has been growing interest in the complex host-microbe interactions within the human gut and the role these interactions play in systemic health and disease. As an essential metabolic organ, the liver is intimately coupled to the intestinal microbial environment via the portal venous system. Our understanding of the gut-liver axis comes almost exclusively from studies of adults; the gut-liver axis in children, who have unique physiology and differing gut microbial communities, remains poorly understood. Here, we provide a comprehensive overview of common pediatric hepatobiliary conditions and recent studies exploring the contributions of the gut microbiota to these conditions or changes of the gut microbiota due to these conditions. We examine the current literature regarding the microbial alterations that take place in biliary atresia, pediatric non-alcoholic fatty liver disease, Wilson's disease, cystic fibrosis, inflammatory bowel disease, and viral hepatitis. Finally, we propose potential therapeutic approaches involving modulation of the gut microbiota and the gut-liver axis to mitigate the progression of pediatric liver disease.

What Makes A "Successful" Kasai Portoenterostomy "Unsuccessful"?

OBJECTIVES

Clearance of jaundice (CoJ) is the first key objective of Kasai portoenterostomy (KPE) for biliary atresia (BA) and its achievement is by far the best index of long-term prognosis. We sought to identify the reasons for failure [subsequent liver transplant (LT)] in this cohort.

METHODS

Review of single-center prospective BA database. Successful KPE was defined by achieving a postoperative bilirubin of ≤20 µmol/L. Pre-KPE and post-KPE variables were identified together with a multivariate logistic regression model to identify those observable at 3 months post-KPE. Data are quoted as median (range). A P value of ≤0.05 was significant.

RESULTS

One hundred thirty-five infants underwent KPE between January 2012 and December 2018, of which 90 (67%) achieved CoJ. From these 20 (22%) (Cohort A) underwent LT with the remainder continuing with native liver (Cohort B) (median follow-up of 4.15 years). There was no difference in age at KPE ( P = 0.41), APRi (aspartate aminotransferase-to-platelet ratio) ( P = 0.07), associated anomalies ( P = 0.7), and cytomegalovirus status ( P = 0.7) between the 2 groups. Postoperatively, both cholangitis [any episode, 18/20 (90%) vs 15/70 (21%); P < 0.0001] and portal hypertension (PHT) [gastrointestinal (GI) bleed, 10/20 (50%) vs 2/70 (2.8%); P < 0.0001] were significantly more common in cohort A. Univariate analysis showed that the most significant predictive values at 3 months for LT by 2 years were high APRi, bilirubin, international normalized ratio, and ultrasound (US)-detected ascites with multivariate logistic modeling confirming these variables with predictive values of r2 = 0.79, AUROC = 0.98.

CONCLUSIONS

Failure is not preordained at KPE but due to recurrent cholangitis and/or symptoms of PHT.

The composition of the gut microbiota is altered in biliary atresia with cholangitis

Aim

To detect the composition of the gut microbiota in biliary atresia after Kasai surgery.

Methods

Infants within six months after the Kasai operation who were diagnosed by cholangiography at Shanghai Children’s Hospital were enrolled in the study. Fecal samples were collected from diapers, placed into sterile tubes in the inpatient department or outpatient department and frozen at −80°C within half an hour. The gut microbiota was detected by 16S rRNA sequences. Then, the patients that were followed up to one year after the Kasai operation who suffered from cholangitis at least one time were grouped into the BAcho group, and the others were grouped into the BAnoncho group.

Results

Nine of 18 BA patients were grouped into the BAcho group, and the others were grouped into the BAnoncho group. In the BAcho group, AST, ALT and GGT were significantly increased compared to the BAnoncho group. The number of total OTUs (operational taxonomic units) in feces was more elevated in the BAnoncho group than in the BAcho group. In the BAnoncho group, the Chao index at the OTU level was significantly increased compared to that in the BAcho group (66.37 ± 21.5 vs. 45.64 ± 11.25, p = 0.02 < 0.05). Bifidobacterium was the most abundant genus in the BAnoncho group, accounting for 22.14%, and Klebsiella accounted for 22.74% in the BAcho group. Compared with the BAnoncho group, Bacteroides was significantly decreased in the BAcho group (p = 0.037).

Conclusion

The composition of the gut microbiota was different between BA with cholangitis and BA without cholangitis.

The difference of gut microbiome in different biliary diseases in infant before operation and the changes after operation

Background

Evidence supports an association between cholestatic liver disease and changes in microbiome composition. Nevertheless, the identification of this special type of biliary atresia from non-biliary atresia cholestasis is still a major clinical difficulty. The purpose of this study is to compare the differences in the composition of gut microbiome between infants with biliary atresia and infant with non-biliary atrestic cholestasis, to find new ways to identify and diagnose these two diseases early, to understand the influence of the presence or absence of bile on the composition of the gut microbiome in infants with cholestasis.

Methods

Using 16S rDNA gene sequencing technology to analyze the intestinal flora of the participants.

Results

In terms of diversity, there is an obvious structural separation in the intestinal microbiota of the BA group and the CD group, and this structural separation also exists in the comparison between the two groups before surgery. Taxonomic analysis demonstrated that the two groups showed an increase in Proteobacteria and Firmicutes before surgery, and the relative abundance of potential pathogens such as Shigella, Streptococcus, Klebsiella, etc. increased, potential probiotics such as Bifidobacteria and Lactobacillus decreased, but the relative abundance of each genus was different between groups. It was found that Enterococcus, Ralstonia, Nitriliruptoraceae, etc. were differentially enriched in the BA group, the CD group are mainly enriched in Veillonella, Clostridium_sensu_stricto_1 and Lactobacillus. Functional analysis of the groups showed that the BA group mainly focused on the processes of energy release processes, and the CD group mainly focused on the biosynthesis of amino-acids to consume energy.

Conclusions

The composition of intestinal flora is different between biliary atresia and non-biliary atretic cholestasis. Enterococcus, Ralstonia, etc. may become biomarkers for the identification and diagnosis of both.

Intestinal Microbiota Participates in the Protective Effect of HO-1/BMMSCs on Liver Transplantation With Steatotic Liver Grafts in Rats

The present study aimed to explore whether heme oxygenase-1 (HO-1)-modified bone marrow mesenchymal stem cells (BMMSCs) have a protective effect on liver transplantation with steatotic liver grafts in rats, and to determine the role of the intestinal microbiota in such protection. HO-1/BMMSCs were obtained by transduction of Hmox1 gene [encoding heme oxygenase (HO-1)]-encoding adenoviruses into primary rat BMMSCs. Steatotic livers were obtained by feeding rats a high-fat diet, and a model of liver transplantation with steatotic liver grafts was established. The recipients were treated with BMMSCs, HO-1/BMMSCs, or neither, via the portal vein. Two time points were used: postoperative day 1 (POD 1) and POD 7. The results showed that under the effect of HO-1/BMMSCs, the degree of steatosis in the liver grafts was significantly reduced, and the level of liver enzymes and the levels of pro-inflammatory cytokines in plasma were reduced. The effect of HO-1/BMMSCs was better than that of pure BMMSCs in the prolongation of the rats' postoperative time. In addition, HO-1/BMMSCs promoted the recovery of recipients' intestinal structure and function, especially on POD 7. The intestinal villi returned to normal, the expression of tight junction proteins was restored, and intestinal permeability was reduced on POD 7. The intestinal bacterial of the LT group showed significantly weakened energy metabolism and overgrowth. On POD 1, the abundance of Akkermansiaceae was higher. On POD 7, the abundance of Clostridiaceae increased, the level of lipopolysaccharide increased, the intestinal mucosal barrier function was destroyed, and the levels of several invasive bacteria increased. When treated with HO-1/BMMSCs, the energy metabolism of intestinal bacteria was enhanced, and on POD 1, levels bacteria that protect the intestinal mucosa, such as Desulfovibrionaceae, increased significantly. On POD 7, the changed intestinal microbiota improved lipid metabolism and increased the levels of butyrate-producing bacteria, such as Lachnospiraceae. In conclusion, HO-1/BMMSCs have protective effects on steatotic liver grafts and the intestinal barrier function of the recipients. By improving lipid metabolism and increasing the abundance of butyrate-producing bacteria, the changed intestinal microbiota has a protective effect and prolongs the recipients' survival time.

Comprehensive Analysis of Gut Microbiota and Fecal Bile Acid Profiles in Children With Biliary Atresia

Background

Biliary atresia (BA) is the most common cholestatic liver disease in neonates. Herein, we aimed at characterizing the gut microbiota and fecal bile acid profiles of BA patients, defining the correlations between them, and evaluating the relationship between the clinical pathogenesis and changes in the gut microbiota and bile acid profiles.

Methods

A total of 84 fecal samples from BA patients (n = 46) and matched healthy controls (HCs, n = 38) were subjected to sequencing by 16S rRNA gene amplification, and fecal bile acid were analyzed by targeted metabolomics.

Findings

Compared with the controls, a structural separation of the intestinal flora of BA patients was uncovered, which was accompanied by changes in the composition of fecal bile acids. In the BA group, Actinobacillus, Monoglobus, and Agathobacter were enriched in patients without cholangitis (p &lt; 0.05). Selenomonadaceae and Megamonas were more abundant in patients without recurrent cholangitis episodes (p &lt; 0.05), while Lachnospiraceae and Ruminococcaceae were enriched in patients with multiple recurrences of cholangitis (p &lt; 0.05). Postoperative jaundice clearance was associated with Campylobacter and Rikenellaceae (p &lt; 0.05), and tauroursodeoxycholic acid was associated with jaundice clearance (p &lt; 0.001).

Conclusion

BA patients are characterized by different compositions of gut microbiota and bile acids, and their interaction is involved in the process of liver damage in BA, which may be closely related to the occurrence of postoperative cholangitis and jaundice clearance.

Effects of Intestinal FXR-Related Molecules on Intestinal Mucosal Barriers in Biliary Tract Obstruction

Background: The farnesoid X receptor (FXR) is a key factor regulating hepatic bile acid synthesis and enterohepatic circulation. Repression of bile acid synthesis by the FXR is a potential strategy for treating cholestatic liver disease. However, the role of intestinal FXR on the intestinal barrier and intestinal microbiota needs further investigation.

Materials: Intestinal tissues were collected from patients with biliary atresia or without hepatobiliary disease. Then, intestinal mRNA levels of FXR-related molecules were determined. To investigate the effect of FXR activation, bile-duct-ligation rats were treated with obeticholic acid [OCA (5 mg/kg/day)] or vehicle (0.5% methyl cellulose) per oral gavage for 14 days. The mRNA levels of intestinal FXR, SHP, TNF-α, FGF15 and bile acid transporter levels were determined. In addition, the intestinal permeability, morphologic changes, and composition of the intestinal microbiota were evaluated. Gut Microbiome was determined by 16S rDNA MiSeq sequencing, and functional profiling of microbial communities was predicted with BugBase and PICRUSt2. Finally, the role of OCA in injured intestinal epithelial cell apoptosis and proliferation was examined by pretreatment with lipopolysaccharide (LPS) in Caco-2 cells.

Results: The downstream of the FXR in ileum tissues was inhibited in biliary obstruction. Activation of the FXR signaling pathway by OCA significantly reduced liver fibrosis and intestinal inflammation, improved intestinal microbiota, and protected intestinal mucosa in BDL rats. OCA also altered the functional capacities of ileum microbiota in BDL rats. Significant differences existed between the controls and BDL rats, which were attenuated by OCA in the alpha diversity analysis. Principal coordinates analysis showed that microbial communities in BDL rats clustered separately from controls, and OCA treatment attenuated the distinction. Bugbase and PICRUSt2 analysis showed that OCA changed the composition and structure of the intestinal microbiota and improved the metabolic function of the intestinal microbiota by increasing the relative abundance of beneficial bacteria and reducing the relative abundance of harmful bacteria. Moreover, OCA reduced the apoptosis induced by LPS in Caco-2 cells.

Conclusion: The FXR agonist, OCA, activates the intestinal FXR signaling pathway and improves the composition and structure of the intestinal microbiota and intestinal barrier in BDL rats.

Update on Etiology and Pathogenesis of Biliary Atresia

Biliary atresia is a rare inflammatory sclerosing obstructive cholangiopathy that initiates in infancy as complete choledochal blockage and progresses to the involvement of intrahepatic biliary epithelium. Growing evidence shows that biliary atresia is not a single entity with a single etiology but a phenotype resulting from multifactorial events whose common path is obliterative cholangiopathy. The etiology of biliary atresia has been explained as resulting from genetic variants, toxins, viral infection, chronic inflammation or bile duct lesions mediated by autoimmunity, abnormalities in the development of the bile ducts, and defects in embryogenesis, abnormal fetal or prenatal circulation and susceptibility factors. It is increasingly evident that the genetic and epigenetic predisposition combined with the environmental factors to which the mother is exposed are potential triggers for biliary atresia. There is also an indication that a progressive thickening of the arterial middle layer occurs in this disease, suggestive of vascular remodeling and disappearance of the interlobular bile ducts. It is suggested that the hypoxia/ischemia process can affect portal structures in biliary atresia and is associated with both the extent of biliary proliferation and the thickening of the medial layer.

Assessment of Lactobacillus casei rhamnosus (LGG) therapy in children with biliary atresia - Randomized placebo controlled trial

BACKGROUND

The role of microbiota in biliary atresia (BA) remains unclear. The aim of our study was to assess efficacy and safety of LGG treatment in children with BA after HPE with special focus on bacterial cholangitis (BCH) and quantitative assessment of the gut microbiota composition and metabolism.

METHODS

We performed double-blind placebo controlled trial with patients randomized into treatment group who received LGG (n = 14) and placebo (n = 16). The gut microbiota and short-chain fatty acids (SCFA) were assessed at baseline and after 6 months of treatment. Clinical and laboratory parameters including episodes of bacterial cholangitis (BCH) were collected during the study period and after 2-year follow-up. Additionally, stool composition of BA patients was compared with healthy age-matched control group.

RESULTS

There were lower concentration of SCFA in children with BA compared to control group and significant increase in the number of Enterococcus bacteria. After 6 months of treatment, neither laboratory parameters nor gut microbiota composition differed between LGG group and placebo. PP analysis results were similar to ITT analysis, no significant differences between study and control group. Overall, there were 11 (36%) patients who developed at least one episode of bacterial cholangitis; 3 (21%) in the LGG group compared to 8 (50%) placebo group (p = 0.14). Bacterial cultures were positive in 22% of cases and recurrence after the first episode was observed in 27% of patients. The level of total bilirubin decreased below 2 mg/dl after 6 months of the study in 6 (42.8%) patients in the LGG group and in 8 (50%) patients in the placebo group (p = 0.73). During 2-year follow-up 6 out of 14 patients (42.8%) in the LGG group and 11 out of 16 placebo patients (68.7%) underwent liver transplantation (p = 0.27).

CONCLUSIONS

Patients with BA present with specific microbiota profiles and decreased SCFA what gives opportunities to implement novel therapeutic options based on modulation of  microbiota. Whether LGG is an effective therapy needs to be studied in a larger group with similar outcome parameters.

Association of Gut Microbiota and Metabolites With Disease Progression in Children With Biliary Atresia

Background and Aims

Biliary atresia is the most common cause of liver disease and liver transplantation in children. The accumulation of bile acids in hepatocytes and the stimulation of the intestinal microbiome can aggravate the disease progression. This study investigated changes in the composition of the gut microbiota and its metabolites in biliary atresia and the possible effects of these changes on disease progression.

Methods

Stool samples of biliary atresia at different disease stages and matched control individuals were collected (early stage: 16 patients, 16 controls; later stage: 16 patients, 10 controls). Metagenomic sequencing was performed to evaluate the gut microbiota structure. Untargeted metabolomics was performed to detect and analyze the metabolites and bile acid composition.

Results

A disturbed gut microbiota structure occurred in the early and later stages of biliary atresia. Klebsiella, Streptococcus, Veillonella, and Enterococcus have always been dominant. The abundance of V. atypica displayed significant changes between the early and later stages of biliary atresia. Combined with clinical indicators, Spearman’s analysis showed that Klebsiella and Veillonella atypica strongly correlated with liver enzymes. Enterococcus faecium had an enormously positive relationship with lithocholic acid derivatives. Metabolites involved in tryptophan metabolism were changed in the patients with biliary atresia, which had a significant association with stool V. atypica and blood total bilirubin (p < 0.05).

Conclusions

The liver damage of biliary atresia was directly or indirectly exacerbated by the interaction of enriched Klebsiella (K. pneumoniae), Veillonella (V. atypica), and Enterococcus (E. faecium) with dysmetabolism of tryptophan and bile acid.

Gut Microbiota Composition of Biliary Atresia Patients Before Kasai Portoenterostomy Associates With Long-term Outcome

BACKGROUND AND AIMS

Biliary atresia (BA) is a cholestatic, fibro-obliterative cholangiopathy of unknown etiology. BA is primarily treated by a surgical approach, that is, the Kasai portoenterostomy (KPE), to obtain clearance of jaundice (COJ). The gut microbiota (GM) composition has been associated with the course of several cholestatic liver diseases. It is largely unknown, however, whether GM composition associates with the outcome of KPE. We compared the GM composition of BA patients and controls and assessed if GM composition before KPE was related to COJ after KPE.

METHODS

We compared feces of term-born BA patients before KPE and controls (patients undergoing inguinal hernia repair) by 16S rRNA sequencing. Composition and alpha diversity of the GM were compared between BA and controls before KPE and after KPE, between patients with COJ versus without COJ (total serum bilirubin < or ≥20 μmol/L <6 months post-KPE).

RESULTS

Alpha diversity was comparable between BA (n = 12, age 1.6 [1.3-1.8] months) and controls (n = 6, age 2.0 [1.4-2.1] months; P = 0.22). Compared with controls, BA patients had lower abundances of Bifidobacteriaceae (β = -1.98, P < 0.001) and Lachnospiraceae (β = -1.84, P = 0.007), and higher abundances of Streptococcus (β = -1.13, P = 0.003). The alpha diversity before KPE correlated negatively with COJ (R = -0.63, P = 0.03). Lower alpha diversity pre-KPE was associated with COJ [+] (βlogit = -0.64, P = 0.04). We observed greater abundances of genus Acinetobacter (β = 1.27, P = 0.03) and family Clostridiaceae (β = 1.45, P = 0.03) and lower abundances of the family Enterobacteriaceae (genera Klebsiella (β = -1.21, P = 0.01), Salmonella (β = -1.57, P = 0.02)) in COJ [+] versus COJ [-].

CONCLUSIONS

The GM of BA patients before Kasai portoenterostomy associates with outcome, clearance of jaundice, suggestive of predictive, and mechanistic roles of the gut microbiota composition in bile homeostasis.

The role of the gut microbiome in graft fibrosis after pediatric liver transplantation

Liver transplantation (LT) is a life-saving option for children with end-stage liver disease. However, about 50% of patients develop graft fibrosis in 1 year after LT, with normal liver function. Graft fibrosis may progress to cirrhosis, resulting in graft dysfunction and ultimately the need for re-transplantation. Previous studies have identified various risk factors for the post-LT fibrogenesis, however, to date, neither of the factors seems to fully explain the cause of graft fibrosis. Recently, evidence has accumulated on the important role of the gut microbiome in outcomes after solid organ transplantation. As an altered microbiome is present in pediatric patients with end-stage liver diseases, we hypothesize that the persisting alterations in microbial composition or function contribute to the development of graft fibrosis, for example by bacteria translocation due to increased intestinal permeability, imbalanced bile acids metabolism, and/or decreased production of short-chain fatty acids (SCFAs). Subsequently, an immune response can be activated in the graft, together with the stimulation of fibrogenesis. Here we review current knowledge about the potential mechanisms by which alterations in microbial composition or function may lead to graft fibrosis in pediatric LT and we provide prospective views on the efficacy of gut microbiome manipulation as a therapeutic target to alleviate the graft fibrosis and to improve long-term survival after LT.

A Higher Incidence of Isolated Biliary Atresia in Rural Areas: Results From an Epidemiological Study in The Netherlands

OBJECTIVES

Environmental factors may be involved in the pathogenesis of biliary atresia (BA). This epidemiological study aimed to analyze the relationships between the incidence of BA, the incidence of confirmed viral or bacterial infections and population density, and geographical and temporal clustering of BA in the Netherlands.

STUDY DESIGN

Correlations between the monthly incidence of BA and the number of confirmed infections were assessed. BA incidence per province was calculated and compared to the province with highest population density. Birthplaces were classified as rural or urban. Temporal clustering of month of birth and month of conception were analyzed. We performed analyses for isolated BA (IBA) and syndromic BA (SBA) separately. Chi2, logistic regression, and Walter and Elwood test were used.

RESULTS

A total of 262 IBA and 49 SBA patients, born between 1987 and 2018, were included. IBA incidence correlated to the number of confirmed infections of, for example, Chlamydia trachomatis (R = 0.14; P = 0.02) and adenovirus (R = 0.22; P = 0.005). We observed a higher incidence of IBA (0.75/10,000; odds ratio [OR] = 1.86; P = 0.04) and SBA (0.27/10,000; OR = 6.91; P = 0.001) in Groningen and a higher incidence of SBA in Gelderland (0.13/10,000; OR = 3.35; P = 0.03). IBA incidence was 68% higher in rural (0.67/10,000) versus urban areas (0.40/10,000) (P = 0.02). The estimated month of conception of patients with SBA clustered in November (85% increase compared to average SBA incidence [0.09/10,000; P = 0.04]).

CONCLUSIONS

IBA incidence correlated weakly with national confirmed infections. IBA and SBA incidence varied geographically in the Netherlands. IBA incidence was higher in rural than in urban areas, which may be explained decreased exposure to pathogens. Our results provide support for a role of environmental factors in the pathogenesis of IBA.

Gut Microbiome: A Potential Modifiable Risk Factor in Biliary Atresia

Biliary atresia (BA) is a fibro-obliterative condition of the biliary tree, presenting in infancy. The bilioenteric conduit formed at Kasai portoenterostomy (KPE), achieves restoration of bile flow in approximately 60% of infants. Even if the operation is successful, cirrhosis and its associated complications are, however, common. BA remains the leading cause for liver transplantation (LT) in children. Antibiotic, choleretic, and steroid therapy post-KPE have not convincingly reduced LT rates. Advances in molecular technology have enabled characterisation of the encoded genes of the gut microbiota (gut microbiome). The gut microbiome plays an important role in host metabolism, nutrition, and immune function, with alterations in its diversity and/or composition, known as dysbiosis, being described in disease states, including liver disease. Liver-gut microbiome exploration in adulthood largely focuses on nonalcoholic liver disease, cirrhosis (mainly alcohol- or viral-based aetiology) and cholestatic liver diseases (eg, primary sclerosing cholangitis), with microbial signatures correlating to disease severity. Investigation of the gut microbiota in BA had been limited to culture-based methodology, but molecular studies are emerging, and although in their infancy, highlight a potential pathogenic role for Enterobacteriaceae and Streptococcus, and a potential beneficial role for Bifidobacteria. Bacterial translocation, and the production of gut microbiome-derived metabolites, are key host-microbiome-mechanistic pathways in liver disease pathogenesis. Microbiome-targeted therapeutics for liver disease are in development, with faecal microbiota transplantation showing promise in cirrhosis. Could the gut microbiome be a novel modifiable risk factor in BA, reducing the need for LT?

Characteristics of the Gut Microbiome and IL-13/TGF-β1 Mediated Fibrosis in Post-Kasai Cholangitis of Biliary Atresia

Aims: Cholangitis in biliary atresia (BA), which accelerates liver fibrosis progression, is among the most common serious complications after Kasai surgery; however, its etiology remains elusive. Gut microbiome migration may contribute to post-Kasai cholangitis. Further, there is no appropriate model of BA post-Kasai cholangitis for use in investigation of its pathogenesis. Methods: We explored the characteristics of gut microbiome in patients with BA before and after Kasai procedure based on 16S rDNA sequencing. We isolated the dominant strain from patient stool samples and established an in vitro model by infecting patient-derived liver organoids. Bulk RNA-seq was performed, and we conducted qPCR, ELISA, and western blot to explore the mechanism of fibrosis. Results: Gut microbiome diversity was lower in patients after, relative to before, Kasai procedure, while the relative abundance of Klebsiella was higher. Patients who developed cholangitis within 1 month after discharge tended to have simpler gut microbiome composition, dominated by Klebsiella. Klebsiella pneumoniae (KPN) was isolated and used for modeling. RNA-seq showed that BA liver organoids expressed markers of hepatic progenitor cells (KRT19, KRT7, EPCAM, etc.) and that organoids were more stable and less heterogeneous among individuals than liver tissues. After infection with KPN, gene expression patterns in BA liver organoids were enriched in pathways related to infection, apoptosis, and fibrosis. Preliminary experiments indicated the presence of IL-13/TGF-β1-mediated fibrosis in post-Kasai cholangitis. Conclusions: Our findings using a newly-developed model, demonstrate a key role for Klebsiella, and a potential mechanism underlying fibrosis in post-Kasai cholangitis, mediated by the IL-13/TGF-β1 pathway.

Current Concepts of Biliary Atresia and Matrix Metalloproteinase-7: A Review of Literature

Biliary atresia (BA) is a rare cholangiopathy of infancy in which the bile ducts obliterate, leading to profound cholestasis and liver fibrosis. BA is hypothesized to be caused by a viral insult that leads to over-activation of the immune system. Patients with BA are surgically treated with a Kasai portoenterostomy (KPE), which aims to restore bile flow from the liver to the intestines. After KPE, progressive liver fibrosis is often observed in BA patients, even despite surgical success and clearance of their jaundice. The innate immune response is involved during the initial damage to the cholangiocytes and further differentiation of the adaptive immune response into a T-helper 1 cell (Th1) response. Multiple studies have shown that there is continuing elevation of involved cytokines that can lead to the progressive liver fibrosis. However, the mechanism by which the progressive injury occurs is not fully elucidated. Recently, matrix metalloproteinase-7 (MMP-7) has been investigated to be used as a biomarker to diagnose BA. MMPs are involved in extracellular matrix (ECM) turnover, but also have non-ECM related functions. The role of MMP-7 and other MMPs in liver fibrosis is just starting to be elucidated. Multiple studies have shown that serum MMP-7 measurements are able to accurately diagnose BA in a cohort of cholestatic patients while hepatic MMP-7 expression correlated with BA-related liver fibrosis. While the mechanism by which MMP-7 can be involved in the pathophysiology of BA is unclear, MMP-7 has been investigated in other fibrotic pathologies such as renal and idiopathic pulmonary fibrosis. MMP-7 is involved in Wnt/β-catenin signaling, reducing cell-to-cell contact by shedding of E-cadherin, amplifying inflammation and fibrosis via osteopontin (OPN) and TNF-α while it also appears to play a role in induction of angiogenesis This review aims to describe the current understandings of the pathophysiology of BA. Subsequently, we describe how MMP-7 is involved in other pathologies, such as renal and pulmonary fibrosis. Then, we propose how MMP-7 can potentially be involved in BA. By doing this, we aim to describe the putative role of MMP-7 as a prognostic biomarker in BA and to provide possible new therapeutic and research targets that can be investigated in the future.

Discovery of Candidate Stool Biomarker Proteins for Biliary Atresia Using Proteome Analysis by Data-Independent Acquisition Mass Spectrometry

Biliary atresia (BA) is a destructive inflammatory obliterative cholangiopathy of the neonate that affects various parts of the bile duct. If early diagnosis followed by Kasai portoenterostomy is not performed, progressive liver cirrhosis frequently leads to liver transplantation in the early stage of life. Therefore, prompt diagnosis is necessary for the rescue of BA patients. However, the prompt diagnosis of BA remains challenging because specific and reliable biomarkers for BA are currently unavailable. In this study, we discovered potential biomarkers for BA using deep proteome analysis by data-independent acquisition mass spectrometry (DIA–MS). Four patients with BA and three patients with neonatal cholestasis of other etiologies (non-BA) were recruited for stool proteome analysis. Among the 2110 host-derived proteins detected in their stools, 49 proteins were significantly higher in patients with BA and 54 proteins were significantly lower. These varying stool protein levels in infants with BA can provide potential biomarkers for BA. As demonstrated in this study, the deep proteome analysis of stools has great potential not only in detecting new stool biomarkers for BA but also in elucidating the pathophysiology of BA and other pediatric diseases, especially in the field of pediatric gastroenterology.

The Fecal Microbiome in Infants With Biliary Atresia Associates With Bile Flow After Kasai Portoenterostomy

BACKGROUND

Biliary atresia's (BA) response to surgical Kasai portoenterostomy (KP) is uneven and dependent upon bile flow; 50% of infants require a liver transplant by 24 months. We hypothesized that the microbiome may identify and associate with outcomes in BA.

METHODS

Stool samples were collected from infants with cholestasis (n = 15), 8 of which with BA were followed longitudinally.16S sequencing was performed on all samples (n = 45). Whole Genome Sequencing (WGS) was performed on BA pre-KP samples (n = 8). Infants with BA, other forms of cholestasis, BA infants with very good bile flow (VGBF) and not (nVGBF) (VGBF dichotomized by TSBA <40 μmol/L by 6 months) were compared.

RESULTS

Of the 8 infants with BA, 4 infants had VGBF. Microbial richness was inversely proportional to degree of cholestasis (P = 0.046). Increased Bifidobacterium abundance associated with VGBF (P = 0.03) and decreased cholestasis (P < 0.01) at 1 month post-KP. Pre-KP, community structure differed in infants with BA versus other cholestasis. Interestingly, infants who subsequently achieved VGBF had increased diversity (P = 0.03) and different community structure at the pre-KP time point. WGS corroborated Bifidobacterium's pre-KP importance.

CONCLUSIONS

The microbiome differs between infants with BA and other cholestasis. It additionally differs between infants with BA who have good and poor bile flow, and thus outcomes, post-KP. These differences are seen even before KP. These data suggest that bile influences the development of the infant microbiome and that there may be possible influences of the pre- and post-KP microbiome on bile flow after KP. Further larger studies are needed to confirm these findings.