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.

Unique bile acid profiles in the bile ducts of patients with primary sclerosing cholangitis.

BACKGROUND: The relationship between primary sclerosing cholangitis (PSC) and biliary bile acids (BAs) remains unclear. Although a few studies have compared PSC biliary BAs with other diseases, they did not exclude the influence of cholestasis, which affects the composition of BAs. We compared biliary BAs and microbiota among patients with PSC, controls without cholestasis, and controls with cholestasis, based on the hypothesis that alterations in BAs underlie the pathophysiology of PSC. METHODS: Bile samples were obtained using endoscopic retrograde cholangiopancreatography from patients with PSC (n = 14), non-hepato-pancreato-biliary patients without cholestasis (n = 15), and patients with cholestasis (n = 13). RESULTS: The BA profiles showed that patients with PSC and cholestasis controls had significantly lower secondary BAs than non-cholestasis controls, as expected, whereas the ratio of cholic acid/chenodeoxycholic acid in patients with PSC was significantly lower despite cholestasis, and the ratio of (cholic acid + deoxycholic acid)/(chenodeoxycholic acid + lithocholic acid) in patients with PSC was significantly lower than that in the controls with or without cholestasis. The BA ratio in the bile of patients with PSC showed a similar trend in the serum. Moreover, there were correlations between the alteration of BAs and clinical data that differed from those of the cholestasis controls. Biliary microbiota did not differ among the groups. CONCLUSIONS: Patients with PSC showed characteristic biliary and serum BA compositions that were different from those in other groups. These findings suggest that the BA synthesis system in patients with PSC differs from that in controls and patients with other cholestatic diseases. Our approach to assessing BAs provides insights into the pathophysiology of PSC.

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.

Clinical and Microbiological Profile of Patients with Acute Cholangitis in a Tertiary Care Center.

INTRODUCTION: Acute cholangitis usually complicates biliary obstruction and antibiotic therapy plays a major role, as an adjunct to adequate biliary drainage in cholangitis. The knowledge of bacterial epidemiology in cholangitis will help to choose antibiotic wisely. The aim of the study was to analyze the clinical and bacteriological profile, in acute cholangitis. MATERIALS: We retrospectively analyzed the patients with acute cholangitis admitted under the Department of Gastroenterology, Kalinga Institute of Medical Sciences, Bhubaneswar August 2020 and July 2022. RESULT: 100 patients with mean age of 53.79 ± 14.96 years (male:female = 48:52) were included in the study. Choledocholithiasis (54%), carcinoma gallbladder (16%) and periampullary carcinoma (13%) were the main cause of biliary obstruction. The most common presenting complaints were fever followed by jaundice, the classically described Charcot's triad was present in only 33 (33%) patients. Most of the patients had moderate cholangitis (52%), followed by mild cholangitis (27%) and severe cholangitis (21%); based on Tokyo 2018 guidelines. Biliary drainage was done by endoscopic retrograde stenting in 92% and percutaneous trans-hepatic drainage in 8% of patients. Bile culture were positive on 86% of patients; gram-negative isolates were in 82.5% (71/86), gram-positive isolates were in 15.2% (13/86) and candida species in 2.3% (2/86). The commonest gram negative organisms isolated were Escherichia coli (34/86) followed by Klebsiella pneumonia (26/86) and Enterococcus faecalis (6/86) being the commonest gram-positive organism. The overall mortality rate was 11%; all had severe cholangitis. CONCLUSION: Choledocholithiasis is the commonest cause of biliary obstruction in patients presenting with acute cholangitis. Escherichia coli and Klebsiella pneumonia are the major contributors to acute cholangitis. References Reiter FP, Obermeier W, Jung J, et al. Prevalence, resistance rates, and risk factors of pathogens in routine bile cultures obtained during endoscopic retrograde cholangiography. Dig Dis 2021;39(1):42-51. Kaya M, Bestas R, Bacalan F, et al. Microbial profile and antibiotic sensitivity pattern in bile cultures from endoscopic retrograde cholangiography patients. World J Gastroenterol 2012;18(27):3585-3589.

Effects of Bile Duct Ligation and Ghrelin Treatment on the Colonic Barrier and Microbiome of Mice.

INTRODUCTION: Cholestatic liver disease (CLD) is associated with intestinal barrier dysfunction. The peptide hormone ghrelin may exert both hepatoprotective and barrier-strengthening effects. Here, we have evaluated these effects under the conditions of experimental cholestasis. METHODS: C57BL/6J mice with bile duct ligation (BDL) or sham surgery were treated with ghrelin or solvent for 9 days. Liver injury was assessed by histological and laboratory analyses. Paracellular macromolecule permeability and transmural electrical resistance (TMER) of colonic tissues were measured using a Ussing chamber. Expression of tight junction (TJ) genes was quantified by real-time PCR. Amplicon metagenomic sequencing was employed to analyze bacterial 16S rRNA from colonic stool samples. RESULTS: Mice with BDL exhibited weight loss and signs of severe liver injury. These changes were unaffected by ghrelin treatment. FITC-4-kDa-dextran flux was increased and TMER decreased after BDL. Treatment with ghrelin tended to reduce these effects. Furthermore, application of ghrelin was associated with higher mRNA levels of claudin-4, occludin, and ZO-1 in colonic tissues of mice with BDL. Reduced alpha-diversity of the microbiome was observed in solvent-treated mice with BDL but not in ghrelin-treated animals. CONCLUSION: Ghrelin treatment did not improve weight loss and liver damage but increased gene expression of colonic TJ proteins and restored the alpha-diversity of the microbiome. Since protective effects of ghrelin might be masked by the severity of the model, we suggest follow-up studies in models of milder CLD.

Comparative analysis of bile culture and blood culture in patients with malignant biliary obstruction complicated with biliary infection.

OBJECTIVE: This study is aimed to provide a clinical basis for the identification and treatment of patients with malignant biliary obstruction (MBO) complicated with biliary infection by comparing pathogenic bacteria detected in bile and blood cultures from these patients. MATERIALS AND METHODS: A total of 380 patients with MBO who received percutaneous transhepatic cholangic drainage from January 2004 to January 2019 were included in the study. A total of 90 patients were diagnosed with having MBO complicated with biliary infection, and bile and blood culture were simultaneously performed on these patients. The patients included 58 men and 32 women, ranging in age from 33 to 86 years old, with a mean age of 60.69 years. RESULTS: The detection rate using bile bacterial culture in patients with MBO complicated with biliary infection was significantly higher than that using blood culture, and there were significant differences in the two kinds of bacterial culture found positive bile and blood cultures from the same patients. Gram-positive cocci were dominant in the bile cultures and Gram-negative bacilli were dominant in the blood cultures. Therefore, it is necessary to conduct simultaneous bile bacterial culture and blood culture for patients with MBO complicated with biliary infection, especially those with severe or critical diseases. CONCLUSIONS: It is vital to enable simultaneous bile bacterial culture and blood culture in patients with MBO complicated with biliary infection. Existing guidelines for the diagnosis and treatment of benign biliary infection are not applicable to patients with MBO complicated with biliary infection.

Intestinal microbiota drives cholestasis-induced specific hepatic gene expression patterns.

Intestinal microbiota regulates multiple host metabolic and immunological processes. Consequently, any difference in its qualitative and quantitative composition is susceptible to exert significant effects, in particular along the gut-liver axis. Indeed, recent findings suggest that such changes modulate the severity and the evolution of a wide spectrum of hepatobiliary disorders. However, the mechanisms linking intestinal microbiota and the pathogenesis of liver disease remain largely unknown. In this work, we investigated how a distinct composition of the intestinal microbiota, in comparison with germ-free conditions, may lead to different outcomes in an experimental model of acute cholestasis. Acute cholestasis was induced in germ-free (GF) and altered Schaedler's flora (ASF) colonized mice by common bile duct ligation (BDL). Studies were performed 5 days after BDL and hepatic histology, gene expression, inflammation, lipids metabolism, and mitochondrial functioning were evaluated in normal and cholestatic mice. Differences in plasma concentration of bile acids (BA) were evaluated by UHPLC-HRMS. The absence of intestinal microbiota was associated with significant aggravation of hepatic bile infarcts after BDL. At baseline, we found the absence of gut microbiota induced altered expression of genes involved in the metabolism of fatty and amino acids. In contrast, acute cholestasis induced altered expression of genes associated with extracellular matrix, cell cycle, autophagy, activation of MAPK, inflammation, metabolism of lipids, and mitochondrial functioning pathways. Ductular reactions, cell proliferation, deposition of collagen 1 and autophagy were increased in the presence of microbiota after BDL whereas GF mice were more susceptible to hepatic inflammation as evidenced by increased gene expression levels of osteopontin, interleukin (IL)-1ß and activation of the ERK/MAPK pathway as compared to ASF colonized mice. Additonally, we found that the presence of microbiota provided partial protection to the mitochondrial functioning and impairment in the fatty acid metabolism after BDL. The concentration of the majority of BA markedly increased after BDL in both groups without remarkable differences according to the hygiene status of the mice. In conclusion, acute cholestasis induced more severe liver injury in GF mice compared to mice with limited intestinal bacterial colonization. This protective effect was associated with different hepatic gene expression profiles mostly related to tissue repair, metabolic and immune functions. Our findings suggest that microbial-induced differences may impact the course of cholestasis and modulate liver injury, offering a background for novel therapies based on the modulation of the intestinal microbiota.

The Gut-Liver Axis in Cholestatic Liver Diseases.

The gut-liver axis describes the physiological interplay between the gut and the liver and has important implications for the maintenance of health. Disruptions of this equilibrium are an important factor in the evolution and progression of many liver diseases. The composition of the gut microbiome, the gut barrier, bacterial translocation, and bile acid metabolism are the key features of this cycle. Chronic cholestatic liver diseases include primary sclerosing cholangitis, the generic term secondary sclerosing cholangitis implying the disease secondary sclerosing cholangitis in critically ill patients and primary biliary cirrhosis. Pathophysiology of these diseases is not fully understood but seems to be multifactorial. Knowledge about the alterations of the gut-liver axis influencing the pathogenesis and the outcome of these diseases has considerably increased. Therefore, this review aims to describe the function of the healthy gut-liver axis and to sum up the pathological changes in these cholestatic liver diseases. The review compromises the actual level of knowledge about the gut microbiome (including the mycobiome and the virome), the gut barrier and the consequences of increased gut permeability, the effects of bacterial translocation, and the influence of bile acid composition and pool size in chronic cholestatic liver diseases. Furthermore, therapeutic implications and future scientific objectives are outlined.

Microbiology of bile in extrahepatic biliary obstruction: A tropical experience.

PURPOSE: Bile is considered sterile, but in obstructed biliary system, growth of micro-organisms results in bacteraemia and toxaemia. We analysed bacterial profile of patients undergoing endoscopic retrograde cholangiopancreatography (ERCP) and evaluated antibiotic resistance patterns to formulate strategy for antibiotics in patients undergoing ERCP. MATERIALS AND METHODS: Patients with cholestasis who underwent ERCP were enrolled. Bile, collected aseptically, was cultured. Positive cultures were processed for isolate identification and antibiotic susceptibility. RESULTS: One hundred and sixty-three patients (78 females; mean age - 55.1 ±â€¯15.8 years) were enrolled and divided into two groups: Group I (n = 99) were naïve and Group II (n = 64) had undergone ERCP and stenting previously. Positive culture was seen in 68.1% (n = 111) with monomicrobial growth in 74.8% (n = 83) and poly-microbial growth in 25.2% (n = 28). Culture positivity was common in Group II vis-a-vis Group I (84.4% vs. 57.5%). Poly-microbial growth was significantly more common in Group II (35.2% vs. 15.8%, P = 0.028). Gram-negative bacilli were the predominant organisms isolated with Escherichia coli, Pseudomonas aeruginosa and Klebsiella pneumoniae comprising 70% of the isolates. The most sensitive antibiotics were piperacillin-tazobactam and imipenem. The sensitivity of vancomycin, against Enterococcus spp. was in the range of 60%-70%. CONCLUSION: Cholestasis leads to bacterial colonisation in most cases, regardless of the presence of a biliary stent. Biliary stent however predisposes to a polymicrobial growth. Most of the commonly used antibiotics continue to have significant sensitivity and may be used empirically. However, previously stented patients may have a higher incidence of infection with Enterococcus spp. and may require specific therapy.

Probiotics improve the neurometabolic profile of rats with chronic cholestatic liver disease.

Chronic liver disease leads to neuropsychiatric complications called hepatic encephalopathy (HE). Current treatments have some limitations in their efficacy and tolerability, emphasizing the need for alternative therapies. Modulation of gut bacterial flora using probiotics is emerging as a therapeutic alternative. However, knowledge about how probiotics influence brain metabolite changes during HE is missing. In the present study, we combined the advantages of ultra-high field in vivo 1H MRS with behavioural tests to analyse whether a long-term treatment with a multistrain probiotic mixture (VIVOMIXX) in a rat model of type C HE had a positive effect on behaviour and neurometabolic changes. We showed that the prophylactic administration of this probiotic formulation led to an increase in gut Bifidobacteria and attenuated changes in locomotor activity and neurometabolic profile in a rat model of type C HE. Both the performance in behavioural tests and the neurometabolic profile of BDL + probiotic rats were improved compared to the BDL group at week 8 post-BDL. They displayed a significantly lesser increase in brain Gln, a milder decrease in brain mIns and a smaller decrease in neurotransmitter Glu than untreated animals. The clinical implications of these findings are potentially far-reaching given that probiotics are generally safe and well-tolerated by patients.

[Mechanism of gut-microbiota-liver axis in the pathogenesis of intestinal failure-associated liver disease].

Intestinal failure (IF) is defined as the critical reduction of functional intestines below the minimum needed to absorb nutrients and fluids, so that intravenous supplementation with parenteral nutrition (PN) is required to maintain health and/or growth. Although the benefits are evident, patients receiving PN can suffer from serious cholestasis due to lack of enteral feeding and small intestinal bacterial overgrowth (SIBO). One such complication that may arise is intestinal failure-associated liver disease (IFALD). Evidences from recent studies suggest that alterations in the intestinal microbiota, as well as intraluminal bile acid driven signaling, may play a critical role in both hepatic and intestinal injury. Since Marshall first proposed the concept of the gut-liver axis in 1998, the role of gut-liver axis disorders in the development of IFALD has received considerable attention. The conversation between gut and liver is the key to maintain liver metabolism and intestinal homeostasis, which influences each other and is reciprocal causation. However, as a "forgotten organ" , intestinal microbiota on the pathogenesis of IFALD has not been well reflected. As such, we propose, for the first time, the concept of gut-microbiota-liver axis to emphasize the importance of intestinal microbiota in the interaction of gut-liver axis. Analysis and research on gut-microbiota-liver axis will be of great significance for understanding the pathogenesis of IFALD and improving the prevention and treatment measures.

Hepatoprotective effects of Huangqi decoction (Astragali Radix and Glycyrrhizae Radix et Rhizoma) on cholestatic liver injury in mice: Involvement of alleviating intestinal microbiota dysbiosis.

ETHNOPHARMACOLOGICAL RELEVANCE: Gut microbiome dysbiosis is closely associated with cholestatic liver disease. Huangqi decoction (HQD), a traditional herbal formula, has protection against cholestatic liver injury. However, the effect of HQD on gut microbiome remains unknown. AIM OF THE STUDY: To investigate the effect of HQD on 3, 5-diethoxycarbonyl-1, 4-dihydrocollidine (DDC) induced cholestatic liver injury and its effect on the gut microbiome profiles. MATERIALS AND METHODS: Mice with DDC-induced cholestatic liver injury were treated with low and high doses of HQD for 8 weeks. Fecal samples were analyzed by 16 S ribosomal DNA sequencing. Barrier function as well as intestinal and hepatic inflammation was analyzed by real-time PCR and western blotting. RESULTS: HQD treatment ameliorated the DDC-induced liver injury and collagen deposition around hepatic bile ducts. Moreover, decreased diversity, reduced richness, and abnormal composition of intestinal microbiota of cholestatic mice were remarkably attenuated by HQD supplementation. Differences in bacterial abundance, including levels of Prevotellaceae_NK3B31_group, Alistipes, and Gordonibacter, were increased in DDC-induced mice, as compared with control mice, and were decreased after HQD treatment. Moreover, intestinal dysbiosis promoted disruption of the intestinal barrier in cholestatic mice. However, HQD treatment alleviated intestinal barrier dysfunction. Importantly, increased hepatic expression of pro-inflammatory factors and the NLRP3 inflammasome, which have a positive correlation with differential bacteria, were characteristics found in DDC-induced cholestatic mice that were alleviated upon treatment with HQD. CONCLUSION: HQD treatment alleviated gut microbiota dysbiosis, ameliorated the intestinal barrier dysfunction, inhibited liver inflammation, and protected against DDC-induced cholestatic liver injury.

Cholestasis and disseminated histoplasmosis in a psoriatic patient on infliximab: case report and review of literature.

BACKGROUND: Histoplasma capsulatum is the most common endemic mycosis in the United States and frequently presents as an opportunistic infection in immunocompromised hosts. Though liver involvement is common in disseminated histoplasmosis, primary gastrointestinal histoplasmosis of the liver in absence of lung involvement is rare. Similarly, cholestatic granulomatous hepatitis in liver histoplasmosis is rarely seen. CASE PRESENTATION: We present a rare case of primary gastrointestinal histoplasmosis manifesting with acute granulomatous hepatitis and cholestasis in a 48-year-old female with psoriatic arthritis, receiving methotrexate and infliximab. The epidemiology, risk factors, clinical presentation, diagnosis, and treatment of histoplasmosis is discussed. Furthermore, we review the published cases of biopsy-proven disseminated histoplasmosis with cholestatic jaundice to highlight histoplasmosis involvement in the liver. CONCLUSION: Histoplasmosis should be considered in immunosuppressed patients with fever, chills, abdominal pain and cholestasis with progressive jaundice, particularly in subjects without evidence of biliary obstruction. Future studies are needed to accurately assess the risk of this fungal infection, specifically in patients on immunomodulatory therapy for autoimmune disease.

Parenteral lipids shape gut bile acid pools and microbiota profiles in the prevention of cholestasis in preterm pigs.

Multi-component lipid emulsions, rather than soy-oil emulsions, prevent cholestasis by an unknown mechanism. Here, we quantified liver function, bile acid pools, and gut microbial and metabolite profiles in premature parenterally fed pigs given a soy-oil lipid emulsion, Intralipid (IL), a multi component lipid emulsion, SMOFlipid (SMOF), a novel emulsion with a modified fatty-acid composition [experimental emulsion (EXP)], or a control enteral diet (ENT) for 22 days. We assayed serum cholestasis markers, measured total bile acid levels in plasma, liver, and gut contents, and analyzed colonic bacterial 16S rRNA gene sequences and metabolomic profiles. Serum cholestasis markers (i.e., bilirubin, bile acids, and γ-glutamyl transferase) were highest in IL-fed pigs and normalized in those given SMOF, EXP, or ENT. Gut bile acid pools were lowest in the IL treatment and were increased in the SMOF and EXP treatments and comparable to ENT. Multiple bile acids, especially their conjugated forms, were higher in the colon contents of SMOF and EXP than in IL pigs. The colonic microbial communities of SMOF and EXP pigs had lower relative abundance of several gram-positive anaerobes, including Clostridrium XIVa, and higher abundance of Enterobacteriaceae than those of IL and ENT pigs. Differences in lipid and microbial-derived compounds were also observed in colon metabolite profiles. These results indicate that multi-component lipid emulsions prevent cholestasis and restore enterohepatic bile flow in association with gut microbial and metabolomic changes. We conclude that sustained bile flow induced by multi-component lipid emulsions likely exerts a dominant effect in reducing bile acid-sensitive gram-positive bacteria.

Intestinal Microbiome-Macrophage Crosstalk Contributes to Cholestatic Liver Disease by Promoting Intestinal Permeability in Mice.

BACKGROUND AND AIMS: Mounting evidence supports an association between cholestatic liver disease and changes in the composition of the microbiome. Still, the role of the microbiome in the pathogenesis of this condition remains largely undefined. APPROACH AND RESULTS: To address this, we have used two experimental models, administering alpha-naphtylisocyanate or feeding a 0.1% 3,5-diethoxycarbonyl-1,4-dihydrocollidine diet, to induce cholestatic liver disease in germ-free mice and germ-free mice conventionalized with the microbiome from wild-type, specific pathogen-free animals. Next, we have inhibited macrophage activation by depleting these cells using clodronate liposomes and inhibiting the inflammasome with a specific inhibitor of NOD-, LRR-, and pyrin domain-containing protein 3. Our results demonstrate that cholestasis, the accumulation of bile acids in the liver, fails to promote liver injury in the absence of the microbiome in vivo. Additional in vitro studies supported that endotoxin sensitizes hepatocytes to bile-acid-induced cell death. We also demonstrate that during cholestasis, macrophages contribute to promoting intestinal permeability and to altered microbiome composition through activation of the inflammasome, overall leading to increased endotoxin flux into the cholestatic liver. CONCLUSIONS: We demonstrate that the intestinal microbiome contributes to cholestasis-mediated cell death and inflammation through mechanisms involving activation of the inflammasome in macrophages.

Cholestasis induced by bile duct ligation promotes changes in the intestinal microbiome in mice.

Increasing evidence point to the relevance of intestinal disfunction and changes in the microbiome composition during chronic liver disease. More specifically, recent studies have highlighted that cholestatic diseases associate with a reduction in the microbiome diversity in patients. Still, the dynamics of the changes in the microbiome composition observed, as well as their implication in contributing to the pathogenesis of this disease remain largely undefined. Hence, experimental mouse models resembling the human pathogenesis are crucial to move forward our understanding on the mechanisms underpinning cholestatic disease and to enable the development of effective therapeutics. Our results show that the bile duct ligation (BDL) experimental model of cholestasis leads to rapid and significant changes in the microbiome diversity, with more than 100 OTUs being significantly different in faecal samples obtained from WT mice at 3 days and 7 days after BDL when compared to control animals. Changes in the microbial composition in mice after BDL included the enrichment of Akkermansia, Prevotella, Bacteroides and unclassified Ruminococcaceae in parallel with a drastic reduction of the presence of Faecalibacterium prausnitzii. In conclusion, our results support that bile duct ligation induces changes in the microbiome that partly resemble the gut microbial changes observed during human cholestatic disease.

Attenuated fibrosis in specific pathogen-free microbiota in experimental cholestasis- and toxin-induced liver injury.

In advanced chronic liver disease (CLD), the translocation of intestinal bacteria and the resultant increase of proinflammatory cytokines in the splanchnic and systemic circulation may contribute to the progression of fibrosis. We therefore speculated that fibrosis and portal hypertension (PHT) would be attenuated in a mouse model of limited intestinal colonization with altered Schaedler flora (ASF) compared to a more complex colonization with specific pathogen-free (SPF) flora. We induced liver fibrosis in ASF and SPF mice by common bile duct ligation (BDL) or by carbon tetrachloride (CCl4) treatment. We then measured portal pressure (PP), portosystemic shunts (PSSs), and harvested tissues for further analyses. There were no differences in PP between sham-treated ASF or SPF mice. After BDL or CCl4 treatment, PP, PSSs, and hepatic collagen deposition increased in both groups. However, the increase in PP and the degree of fibrosis was significantly higher in ASF than SPF mice. Expression of fibrotic markers α-smooth muscle actin, desmin, and platelet-derived growth factor receptor ß were significantly higher in ASF than SPF mice. This was associated with higher activation of hepatic immune cells (macrophages, neutrophils) and decreased expression of the intestinal epithelial tight junction proteins (claudin-1, occludin-1). In 2 models of advanced CLD, SPF mice presented significantly attenuated liver injury, fibrosis, and PHT compared to ASF mice. In contrast to our hypothesis, these findings suggest that a complex intestinal microbiota may play a "hepato-protective" role.-Moghadamrad, S., Hassan, M., McCoy, K. D., Kirundi, J., Kellmann, P., De Gottardi, A. Attenuated fibrosis in specific pathogen-free microbiota in experimental cholestasis- and toxin-induced liver injury.

The gut microbial influence on cholestatic liver disease.

Patients with cholestatic liver diseases like primary sclerosing cholangitis (PSC) and primary biliary cholangitis (PBC) have a different gut microbiome composition than healthy controls. In contrast with PBC, PSC has a strong association with inflammatory bowel disease and is the prototypical disease of the gut-liver axis. Still, there are some distinct overlapping microbial features in the microbiome of patients with PSC and PBC suggesting similarities in cholestatic diseases, although the possible pathogenetic involvement of these shared microbial changes is unknown. Herein, we present an overview of the available data and discuss the relevance for potential disease relevant host-microbiota interactions. In general, the microbiome interacts with the host via the immunobiome (interactions between the host immune system and the gut microbiome), the endobiome (where the gut microbiome contributes to host physiology by producing or metabolizing endogenous molecules) and the xenobiome (gut microbial transformation of exogenous compounds, including nutrients and drugs). Experimental and human observational evidence suggest that the presence and functions of gut microbes are relevant for the severity and progression of cholestatic liver disease. Interestingly, the majority of new drugs that are currently being tested in PBC and PSC in clinical trials act on bile acid homeostasis, where the endobiome is important. In the future, it will be paramount to perform longitudinal studies, through which we can identify new intervention targets, biomarkers or treatment-stratifiers. In this way, gut microbiome-based clinical care and therapy may become relevant in cholestatic liver disease within the foreseeable future.

Fecal Microbiomes in Premature Infants With and Without Parenteral Nutrition-Associated Cholestasis.

INTRODUCTION: Premature infants often require parenteral nutrition (PN) until they reach enteral autonomy which puts them at risk of developing PN-associated cholestasis (PNAC). We sought to compare longitudinal changes in fecal microbiomes of premature infants who developed PNAC versus those who did not despite being on similar PN doses. METHODS: Stool samples from premature infants (gestational age <30 weeks) who developed direct bilirubin ≥1.5 mg/dL while receiving PN were classified as precholestasis, cholestasis, or postcholestasis based on bilirubin levels at the time of sample acquisition and were compared to matched control groups 1, 2, and 3, respectively. RESULTS: A total of 102 fecal samples from 8 cases and 10 controls were analyzed. Precholestasis samples were more abundant in phylum Firmicutes and genus Staphylococcus, whereas control 1 was more abundant in phylum Proteobacteria and genus Escherichia-Shigella. Nonmetric multidimensional scaling ordination plots based on the taxonomic composition of early fecal samples revealed significant separation between cases and controls. On indicator species analysis, genus Bacilli was more prevalent in samples from the precholestasis group, whereas genus Escherichia-Shigella was more prevalent in control 1. With feeding advances, weaning of PN and resolution of PNAC, most differences in microbiota resolved with the exception of control 3 group being more diverse compared to the postcholestasis group. CONCLUSIONS: Premature neonates who develop PNAC, compared to those who do not, show significantly different fecal microbiomes preceding the biochemical detection of cholestasis.

Association of serum bilirubin in newborns affected by jaundice with gut microbiota dysbiosis.

BACKGROUND AND AIMS: Breast milk jaundice (BMJ) is common and benign, but neonatal cholestasis (NC) is rare and not benign, so early differentiation between NC and non-NC jaundice is important and may facilitate diagnosis and treatment. Gut microbiota plays an important role in enterohepatic circulation, which in turn plays an important role in the secretion of bilirubin. We aimed to determine the composition of gut microbiota in patients with NC and BMJ, and to identify the gut microbiota composition associated with NC and BMJ. METHODS: Data on age, gender, delivery, feeding mode, serum total bilirubin, direct bilirubin, and liver function were collected for NC patients, BMJ patients and healthy controls, respectively. Shotgun metagenomic sequencing and metagenome-wide association were performed. RESULTS: Forty NC patients, 16 patients affected by BMJ, and 14 healthy controls (CON) without jaundice were enrolled. A significant increase in species richness, especially Bacteroides, was found in NC patients. The abundances of potentially pathogenic species and KEGG orthologies (KOs) of virulence factor genes were positively correlated with serum bilirubin level. The abundances of nine species of Bifidobacterium and three KOs of galactose metabolism were significantly decreased in the jaundice group (NC and BMJ) and were negatively correlated with serum bilirubin level. CONCLUSIONS: The gut microbiota in NC patients is characterized by a significant increase in species richness, possibly due to the proliferation of potentially pathogenic species. Additionally, the gut microbiota in jaundice patients is characterized by a decreased abundance of Bifidobacterium. Decreased Bifidobacterium has been associated with elevated bilirubin and abnormal gut microbiota galactose metabolic pathway. Further, ten bacteria species were identified as potential biomarker of jaundice. KEY POINTS: Question Is there any alteration of gut microbiotain neonatal cholestasis patients? Does gut microbiota have any involvement in the occurrence of neonatal cholestasis or breast milk jaundice? Findings The alteration of gut microbiota in neonatal cholestasis patients mainly manifested as a significant increase in species richness and an increased abundance of potentially pathogenic species, while the main manifestation in jaundice patients was a significant decrease in Bifidobacterium which may be involved in the metabolism of bilirubin through the galactose metabolic pathway. Meaning The results suggest that an imbalance of gut microbiota exist in neonatal cholestasis and breast milk jaundice patients, primarily in the form of a substantial reduction in the abundance of Bifidobacterium, suggesting the possibility of intervention treatment for neonatal cholestasis and breast milk jaundice by supplementing probiotics.