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

"Post-Kasai Portoenterostomy Cholangitis: What Have We Learnt So Far?"

Post-Kasai portoenterostomy (KPE) cholangitis is one of the most common complications that has a negative impact on liver function and native liver survival. Early diagnosis and judicious empiric antimicrobial management are, therefore, important to prevent further liver damage and decompensation. However, there is no consensus regarding the standard definition of post-KPE cholangitis, and established guidelines on evaluation and management are also lacking. Metagenomic next-generation sequencing, a new molecular diagnostic technique, has the potential for detecting broader spectrum of pathogens, especially in blood culture-negative patients. Antibiotic prophylaxis to prevent cholangitis has been widely used, but questions over the choice of antibiotics, route of administration, and optimal duration remain unsettled. The available evidence on the efficacy of antibiotic prophylaxis in preventing cholangitis has shown conflicting results. This review offers a summary of the current research on advances in diagnostic approaches, including molecular techniques, and therapeutic challenges in managing intractable cholangitis.

A comprehensive clinical and microbiological study on the diagnosis and management of cholangitis in patients with biliary atresia undergoing kasai portoenterostomy

BACKGROUND AND OBJECTIVES

Kasai-portoenterostomy (KPE) is the initial attempt to restore the bile flow and salvage the native liver in biliary atresia (BA) patients. Cholangitis is a frequent complication after KPE and adequate treatment impacts the long-term outcome. The aim of our study is to assess the severity of cholangitis episodes in a cohort of BA patients post KPE, identify the causative agents, using several diagnostic methods, as well as to assess the tolerability and efficacy of our antimicrobial protocol.

METHODS

This analytical retrospective observational study, conducted at Pediatric Hepatology Unit, Cairo University Pediatric Hospital, included infants and children with cholangitis post-KPE enrolled over 30 months. Clinical data collection, basic laboratory investigations inflammatory markers, B-D glucan, blood culture, 16SrDNA, 18SrDNA were performed in all enrolled patients. Cholangitis episodes were treated with intravenous antibiotics according to our antimicrobial protocol that has been implemented in conjunction with the antimicrobial stewardship committee.

RESULTS

This study included 30 post-KPE patients, who experienced 47 episodes of cholangitis. Twenty-five episodes of cholangitis were culture positive cholangitis (positive blood culture and/or PCR results and/or liver biopsy). Klebsiella Variicola and Klebsiella pneumoniae were the most prevalent pathogens in 13 and seven cultures, respectively. Meropenem was the most successful antibiotic in the eradication of infection in 11(23.4%) episodes. Culture positive cholangitis showed increased incidence of sepsis and worse outcome in comparison to culture negative cholangitis. The severity of cholangitis was classified into 16 patients (34%) with infection, 28 (60%) sepsis, one (2%) severe sepsis and two (4%) septic shock.

CONCLUSION

Almost half of cholangitis episodes were culture-positive; the commonest pathogen was Klebsiella, showing more severe sepsis and worse outcome.

LncRNA MEG9 Promotes Inflammation and Liver Fibrosis Through S100A9 in Biliary Atresia

BACKGROUND

The pathogenesis of biliary atresia (BA) remains elusive. We aimed to investigate the role of long noncoding RNA (lncRNA) MEG9 in BA.

METHODS

LncRNA microarray was conducted to identify differentially expressed lncRNAs in three BA and three para-hepatoblastoma liver tissues. RT-qPCR validated the results. Human intrahepatic bile duct epithelial cells (HIBECs) were stably transfected with lncRNA MEG9 knockdown/overexpression to investigate its cellular localization and function. RNA sequencing (RNA-seq), differentially expressed genes (DEGs) analysis and gene set enrichment analysis were applied to MEG9-overexpresed HIBECs. RNA pull-down and mass spectrometry explored the interacting protein of MEG9, while clinical information was reviewed.

RESULTS

436 differentially expressed lncRNAs were identified, with MEG9 highly upregulated in BA. RT-qPCR further confirmed MEG9's overexpression in BA and diagnostic potential (AUC = 0.9691). MEG9 was predominantly located in the nucleus and significantly promoted cell proliferation and migration. RNA-seq revealed inflammation- and extracellular matrix-related pathways enriched in MEG9-overexpressing HIBECs, with upregulated cytokine genes like CXCL6 and IL6. MMP-7 and collagen I were also overexpressed. Furthermore, 38 proteins were identified to specifically interact with MEG9, and S100A9 was highly expressed in cell models. S100A9 was also significantly upregulated in BA liver tissue and correlated with MEG9 expression (r = 0.313, p < 0.05), albumin level (r = -0.349, p < 0.05), and platelet level (r = -0.324, p < 0.05).

CONCLUSION

MEG9 influences cholangiocyte proliferation, migration, and cytokine production, potentially regulating BA inflammation and fibrosis via S100A9 interaction.

Bacillus coagulans alleviates hepatic injury caused by Klebsiella pneumoniae in rabbits

BACKGROUND

As an opportunistic bacterial pathogen, Klebsiella pneumoniae (KP) is prone to causing a spectrum of diseases in rabbits when their immune system is compromised, which poses a threat to rabbit breeding industry. Bacillus coagulans (BC), recognized as an effective probiotic, confers a variety of benefits including anti-inflammatory and antioxidant properties.

AIM

The purpose of this study was to investigate whether dietary BC can effectively alleviate hepatic injury caused by KP.

METHODS

In this study, the rabbits were initially pretreated with varying doses of BC (1×106, 5×106, and 1×107 CFU/g), followed by a challenge with KP at a concentration of 1011 CFU/mL. Liver tissues were harvested and processed for histological assessment using H&E and VG stains to assess structural alterations. Biochemical assays were employed to quantify the enzymatic activities of T-SOD and GSH-Px, as well as the MDA content. Furthermore, ELISA was utilized to detect the levels of inflammatory cytokine (IL-10, IL-6, IL-1β and TNF-α) and apoptotic-related gene (Bcl-2, Bax).

RESULTS

Morphological observation indicated that BC can effectively mitigate KP-induced hepatic sinusoidal dilatation and congestion, as well as ameliorate the degree of hepatic fibrosis. Further analysis showed that BC significantly lowered MDA level in KP-treated rabbits, while enhanced the activities of T-SOD and GSH-Px. Additionally, ELISA result showed that BC pretreatment significantly reduced the levels of pro-inflammatory cytokines TNF-a, IL-6, IL-1β and pro-apoptotic gene Bax, while increasing the levels of anti-inflammatory cytokine IL-10 and anti-apoptotic gene Bcl-2 in KP-treated rabbits.

CONCLUSION

Above data indicate that BC supplementation effectively attenuated oxidative stress and inflammatory response induced by KP through augmenting the activities of antioxidant enzymes and diminishing the levels of pro-inflammatory factors. Furthermore, it reduced the Bax/Bcl-2 ratio in the liver, thereby inhibiting KP-induced apoptosis. The treatment group receiving 5x106 CFU/g BC benefitted most from the protective effect.

Molecular Mechanisms of Fibrosis in Cholestatic Liver Diseases and Regenerative Medicine-Based Therapies

The aim of this review is to explore the potential of new regenerative medicine approaches in the treatment of cholestatic liver fibrosis. Cholestatic liver diseases, such as primary biliary cholangitis (PBC), primary sclerosing cholangitis (PSC), and biliary atresia (BA), due to the accumulation of bile, often progress to liver fibrosis, cirrhosis, and liver failure. When the disease becomes severe enough to require liver transplantation. Deeply understanding the disease's progression and fibrosis formation is crucial for better diagnosis and treatment. Current liver fibrosis treatments mainly target the root causes and no direct treatment method in fibrosis itself. Recent advances in regenerative medicine offer a potential approach that may help find the ways to target fibrosis directly, offering hope for improved outcomes. We also summarize, analyze, and discuss the current state and benefits of regenerative medicine therapies such as mesenchymal stem cell (MSC) therapy, induced pluripotent stem cells (iPSCs), and organoid technology, which may help the treatment of cholestatic liver diseases. Focusing on the latest research may reveal new targets and enhance therapeutic efficacy, potentially leading to more effective management and even curative strategies for cholestatic liver diseases.

Post-Kasai cholangitis evaluation and management strategies: Review of the literature with insights from the Swiss Biliary Atresia Registry

Cholangitis, defined as the inflammation of the bile ducts, is the most frequent complication after Kasai hepatoportoenterostomy in patients with biliary atresia (BA). This review seeks to provide a comprehensive synthesis of current knowledge on diagnosing and managing BA-associated cholangitis while identifying gaps in the existing literature. A scoping literature review was conducted to gather global insights into the definition, evaluation, and management of post-Kasai cholangitis, illustrated through data from the Swiss Biliary Atresia Registry (SBAR). In the literature many different decision algorithms exist for BA-associated cholangitis underlining the clear need for standardizing diagnostic criteria. As an illustration, in 2015 the Swiss center introduced structured guidelines to diagnose BA-associated cholangitis. Upon retrospective analysis of SBAR data (2010-2022) we noted significant differences in disease management before and after implementation: The number of multiple diagnosed cholangitis episodes was reduced and we observed a reduced transplantation rate. Building on this, the Biliary Atresia and Related Diseases consensus has developed key diagnostic and management guidelines with objective criteria that have yet to undergo prospective validation. Indeed, prospective multicenter assessment is clearly needed to enhance acceptance and improve outcomes. Further, rigorous evaluation of prophylactic and therapeutic interventions, including antibiotics and immunomodulatory treatments, seems essential, with randomized trials required to establish their effectiveness and explore microbiota modulation in cholangitis management. The BA-community should strive to establish and adopt a widely accepted protocol for the diagnosis, management and prevention of BA-associated cholangitis. The implementation of such protocols is expected to significantly improve clinical outcomes for these patients.

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.

Systematic review of the mechanism and assessment of liver fibrosis in biliary atresia

PURPOSE

This study systematically reviewed our team's research on the mechanism and assessment of liver fibrosis in BA, summarized our experience, and discussed the future development direction.

METHODS

In this study, Pubmed and Wanfang databases were searched to collect the literature published by our team on the mechanisms of liver fibrosis in BA and the assessment of liver fibrosis in BA, and the above research results were systematically reviewed.

RESULTS

A total of 58 articles were retrieved. Among the included articles, 25 articles related to the mechanism of liver fibrosis in BA, and five articles evaluated liver fibrosis in BA. This article introduces the key pathways and molecules of liver fibrosis in BA and proposes a new grading system for liver fibrosis in BA.

CONCLUSIONS

The new BA liver fibrosis grading method is expected to assess children's conditions, guide treatment, and improve prognosis more accurately. In addition, we believe that the TGF-β1 signaling pathway is the most important in the study of liver fibrosis in BA, and at the same time, the study of EMT occurrence in BA should also be deepened to resolve the controversy on this issue.

The mechanism of IL-13 targeting IL-13Rα2 in regulating oral mucosal FBs through PI3K/AKT/mTOR

OBJECTIVE

The objective of this investigation was to examine the presence of interleukin (IL)-13 and its receptor IL-13Rα2 in the tissues of oral submucous fibrosis (OSF), investigate their biological functions, and explore the underlying mechanisms involved in the development of OSF.

MATERIALS AND METHODS

The expression of IL-13 and IL-13Rα2 in the oral mucosa of patients with OSF and normal individuals was determined through immunohistochemistry and reverse transcription-quantitative polymerase chain reaction (RT-qPCR). Primary fibroblasts (FBs) were extracted through enzymatic digestion and then cultured. Immunofluorescence was employed to identify the FB cultures and the location of IL-13Rα2. The effects of IL-13/IL-13Rα2/PI3K/AKT/mTOR on the migration, proliferation, and secretion of fiber-related proteins of FBs were explored via the wound healing assay, CCK-8 assay, EDU assay, and RT-qPCR. The impact of IL-13Rα2 silencing and PI3K/AKT inhibition on the effect of IL-13 on FBs was analyzed by RT-qPCR and Western blotting.

RESULTS

IL-13 and IL-13Rα2 were highly expressed in OSF. Primary FBs were successfully extracted and cultured. IL-13Rα2 was found to be localized in myofibroblasts. IL-13 promoted the proliferation, migration, and secretion of fibril-associated proteins in FBs. The proliferation, migration, and secretion of fibril-associated proteins of FBs were decreased following IL-13Rα2 silencing and inhibition of the PI3K/AKT/mTOR pathway.

CONCLUSION

IL-13 may promote the proliferation, migration, and secretion of fiber-related proteins of FBs through the PI3K/AKT/mTOR pathway by targeting IL-13Rα2.

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.

Immunomodulatory Effects of Microbiota-Derived Short-Chain Fatty Acids in Autoimmune Liver Diseases

Nonpathogenic commensal microbiota and their metabolites and components are essential to maintain a tolerogenic environment and promote beneficial health effects. The metabolic environment critically impacts the outcome of immune responses and likely impacts autoimmune and allergic responses. Short-chain fatty acids (SCFAs) are the main metabolites produced by microbial fermentation in the gut. Given the high concentration of SCFAs in the gut and portal vein and their broad immune regulatory functions, SCFAs significantly influence immune tolerance and gut-liver immunity. Alterations of SCFA-producing bacteria and SCFAs have been identified in a multitude of inflammatory diseases. These data have particular significance in primary biliary cholangitis, primary sclerosing cholangitis, and autoimmune hepatitis because of the close proximity of the liver to the gut. In this focused review, we provide an update on the immunologic consequences of SCFA-producing microbiota and in particular on three dominant SCFAs in autoimmune liver diseases.

Single-cell transcriptional profiling reveals heterogeneity and developmental trajectories of Ewing sarcoma

PURPOSE

Ewing sarcoma (EwS) is an aggressive malignant neoplasm composed of small round cells. The heterogeneity and developmental trajectories of EwS are uncertain.

METHODS

Single-cell RNA sequencing was performed on 4 EwS tumor tissue samples, and 3 transcriptional atlases were generated. K-nearest neighbor algorithm was used to predict the origin of tumor cells at single-cell resolution. Monocle2 package was used to perform pseudotime trajectory analysis in tumor cells. Differentially expressed genes were compared against those in all other clusters via the FindMarkers function, and then they were subjected to GO analysis using clusterProfiler package.

RESULTS

Combined with the results of k-nearest neighbor algorithm and pseudotime trajectory analysis in tumor cells, we thought meningeal EwS originated from neural crest cells during epithelial to mesenchymal transition and simulated the process of neural crest cell lineage differentiation. But for perirenal EwS and spinal EwS, we hypothesized that after the neural crest cell lineage mutated into them, the tumor cells did not maintain the differentiation trajectory of neural crest cell lineage, and the development trajectory of tumor cells became chaotic. GO analysis results showed that interferon signaling pathway-related biological processes play an essential role in the tumorigenesis and tumor progression process of EwS, and among these biological processes genes, JAK1 gene up-regulated most significantly and highly expressed in all tumor cells. Ruxolitinib was used to explore the function of JAK1. Targeting JAK1 can promote apoptosis of EwS tumor cells, inhibit the migration and invasion of EwS tumor cells, and inhibit cell proliferation by inducing cell cycle S phase arrest.

CONCLUSION

EwS was derived from neural crest cell lineage with variable developmental timing of oncogenic conversion, and the JAK1 might be a candidate for therapeutic targets of EwS.