Bile-acid-induced cell injury and protection

Lead promoted bile acid deconjugation by modulating gut bacteria encoding bile salt hydrolase (BSH) in Rana chensinensis tadpoles

Bile salt hydrolase (BSH) is produced by gut bacteria and is responsible for deconjugating amino acids from the aliphatic side chains of conjugated bile acids (BAs), initiating the critical first step in BAs metabolism. Lead (Pb) is known to cause gut microbial dysbiosis, but whether it affects BAs profiles by reshaping the gut microbiota remains elusive. Here, using targeted BAs metabolomics and metagenomics sequencing, we found that 200 μg/L Pb treatment led to a significant increase in the abundance of BSH-producing microbiota (e.g., Eubacterium and Yersinia), thus promoting the deconjugation of taurocholic acid (TCA) and taurochenodeoxycholic acid (TCDCA). Consequently, the accumulation of relatively hydrophobic BAs cholic acid (CA) and chenodeoxycholic acid (CDCA) may cause damage to enterocytes (e.g., reduced microvilli and enterocyte heights), which attenuated tadpole digestion and ultimately led to significant reductions in morphological parameters. The inhibition of tadpole growth by Pb toxicity may negatively affect their survival and even increase their risk of death. Overall, these results revealed for the first time the toxicological mechanism by which Pb reshapes the gut microbiota and thus disrupts the BAs profile, shedding new insights into the detrimental effects of Pb toxicity on amphibian growth.

Targeted quantitative analysis of urinary bile acids by liquid chromatography-tandem mass spectrometry: Method development and application to healthy and obese children

Bile acids (BA) are C24 steroids synthesized from cholesterol in liver. Hardly any data exist on BA in the most accessible human biofluid urine. As bile acids bear great potential as future biomarkers in diagnosis and monitoring of metabolic diseases, we aimed at developing and implementing a new method for the quantification of urinary bile acids using targeted liquid chromatography-tandem mass spectrometry (LC-MS/MS). A second goal consisted in creating first reference values of urinary bile acids during childhood and to investigate their excretion patterns in obese children and adolescents. Our method required 2 mL of urine and sample preparation consisting of protein precipitation and solid phase extraction. Stable isotopes of BA were included as internal standards (IS). Our method is capable of simultaneously determining 18 BA: the primary BA cholic acid (CA) and chenodeoxycholic acid (CDCA), and the secondary BA deoxycholic acid (DCA) and lithocholic acid (LCA) as well as glycine and taurine conjugates of these four BA. Furthermore, ursodeoxycholic acid (UDCA) and five BA in their sulfated forms (LCA-S, GLCA-S, TLCA-S, GCDCA-S, GDCA-S) were analyzed. After successful validation (intra-day precision 1.02 % - 11.07 %; inter-day precision 0.42-11.47 %.; intra-day accuracy 85.75 % - 108.90 %; inter-day accuracy 86.76 % - 110.99 %; no significant matrix effect; recovery 90.49 % - 113.99 %)., the method was applied to samples of 80 healthy children as well as 237 obese children of various age groups. Sulfated BA showed the highest concentrations, with GCDCA-S (nmol/L, medians, controls vs. obese 588.4 vs. 360.2) being the most abundant among all BA, followed by GLCA-S (353.9 vs. 344.8) and GDCA-S (319,3 vs. 323.9). CA (135.1 vs. 174.6) and GCA (100.2 vs. 92.4) were the two dominant non-sulfated BA. In conclusion, we developed a LC-MS/MS method for the simultaneous determination of 18 urinary bile acids in children and adolescents. We created reference values and investigated obese children. Sulfated bile acids dominated in both study groups. Lower bile acid sulfation and amidation in obese children point to limitations in their hepatic metabolic capacity.

Therapeutic potential of heat-killed Lactobacillus reuteri against bile acid-induced male reproductive toxicity

Exposure of testicular tissue to supraphysiological concentrations of bile acids can lead to infertility. This study aimed to investigate the protective effects of heat-killed Lactobacillus reuteri (L. reuteri) against male reproductive toxicity induced by bile duct ligation (BDL). Thirty-two male Wistar rats were randomly assigned to four groups (N = 8): control normal (CN), sham-control (SC), BDL-control (underwent BDL surgery), and BDL + heat-killed L. reuteri (received probiotic supplementation for 7 days before and 21 days after BDL). At the end of the study, reproductive parameters, including sex hormones, sperm characteristics, oxidative stress markers, antioxidant status, and inflammatory gene expression in testicular tissue, were analyzed. Additionally, histological assessments of the testis and epididymis were performed. The administration of heat-killed L. reuteri significantly improved sperm viability (p ≤ 0.05) and luteinizing hormone levels (p ≤ 0.05) while reducing total oxidative status, carbonyl protein, and oxidative stress index (p ≤ 0.05) compared to the BDL-control group. Moreover, nitric oxide levels were significantly increased (p ≤ 0.05) in the probiotic-treated group. The expression levels of TNF-α and IL-6 were notably downregulated (p ≤ 0.05), indicating reduced testicular inflammation. Histological analysis demonstrated significant improvements in epithelial height, spermatogenic epithelial area ratio, lumen diameter, and lumen area (p ≤ 0.05) in the probiotic-treated group. These findings suggest that heat-killed L. reuteri alleviates cholestasis-related male reproductive toxicity through its antioxidant and anti-inflammatory effects.

Cholic acid inhibits ovarian steroid hormone synthesis and follicular development through farnesoid X receptor signaling in mice

This study investigated the effects of cholic acid (CA) on steroid hormone synthesis and follicular development in mouse ovaries and the regulatory mechanism of CA on the expression of steroidogenesis-related genes in granulosa cells. The mice were divided into control and CA groups, and serum and ovarian samples were collected after 1, 2, and 4 months of treatment, respectively. The results showed that CA treatment for 1, 2, and 4 months reduced ovarian weights, disrupted the estrous cycle, decreased the numbers of antral follicles and corpora lutea, and lowered the serum levels of progesterone and estradiol. Moreover, in the ovary, CA treatment upregulated the expression of farnesoid X receptor (FXR) and downregulated the expression of steroidogenesis-related genes, including StAR, CYP11A1, and HSD3B1. Mechanistically, FXR knockdown reversed the inhibitory effects of CA on steroidogenesis-related gene expression and cholesterol uptake in granulosa cells. In vitro follicle culture experiments further confirmed that CA suppressed follicle development, decreased the mRNA expression of steroidogenesis-related genes, and reduced progesterone and estradiol secretion. Collectively, our results demonstrated that CA inhibited follicular development and steroid hormone synthesis through FXR signaling.

Bromine signature coded derivatization LC-MS for specific profiling of carboxyl or carbonyl-containing metabolites in Mycoplasma pneumoniae infection

Carboxyl or carbonyl-containing metabolites (CoCCMs) are widely distributed in biological samples. Global profiling of CoCCMs is essential for ascertaining specific functions of metabolites and their potential physiological roles in biogenic activities. However, simultaneous determination of these compounds is hampered by poor ionization efficiency, vast polarity differences, wide discrepancy of concentration ranges. Herein, a novel bromine isotope derivatization reagent 5-bromo-2- hydrazinopyridine was employed for CoCCMs profiling by liquid chromatography-mass spectrometry (LC-MS). This method enabled rapid derivatization of 44 CoCCMs under mild conditions. Enhanced separation efficiencies, detection sensitivities, and distinctive MS fragmentation characteristics were observed. Furthermore, this method was demonstrated to be efficient in revealing metabolic alternations, and abnormal serum levels of 6-keto-PGF1α, 12(S)-HHTrE, 15(S)-HEPE and N-acetyl tryptophan were disclosed for the first time in Mycoplasma pneumoniae (MP) infectious patients. Finally, based on the distinctive 2 Da differences of molecular ion peak pairs with almost 1:1 intensity ratio originated from 79Br and 81Br isotopes, an MS-DIAL and Python assisted MS1 isotope screening-MS2 fragments characterization combination strategy was developed for rapid screening, classification, and identification of detected CoCCMs. A total of 1069 CoCCMs were detected, of which 198 CoCCMs were identified in untargeted analysis. Statistical analysis revealed altered metabolic pathways, while glutamic acid, oxoglutaric acid, succinic acid, pyruvic acid, glyceric acid, and glycine were selected as potential biomarkers of MP infection. This bromine signature coded derivatization-LC-MS approach was proved to be a valuable tool for global probing of CoCCMs in biological samples with high sensitivity and broad coverage.

Transcriptomic analysis in liver spheroids identifies a dog-specific mechanism of hepatotoxicity for amcenestrant

Therapeutic drugs can sometimes cause adverse effects in a nonclinical species that do not translate to other species, including human. Species-specific (rat, dog, and human) in vitro liver spheroids were employed to understand the human relevance of cholestatic liver injury observed with a selective estrogen receptor degrader (amcenestrant) in dog, but not in rat, during preclinical development. Amcenestrant showed comparable cytotoxicity in liver spheroids from all 3 species; however, its M5 metabolite (RA15400562) showed dog preferential cytotoxicity after 7 days of treatment. Whole genome transcript profiles generated from liver spheroids revealed downregulation of genes related to bile acid synthesis and transport indicative of strong farnesoid X receptor (FXR) antagonism following treatment with both amcenestrant and its M5 metabolite in the dog but not in rat or human. In human spheroids, upregulation of genes for detoxification enzymes indicative of pregnane X receptor (PXR) agonism was observed following amcenestrant treatment, whereas in the dog these genes were downregulated. The M5 metabolite showed gene dysregulation indicating PXR agonism in both rat and human, and antagonism in dog. Analysis of liver samples from a 3-mo dog toxicity study conducted with amcenestrant showed downregulation of several genes associated with PXR and FXR, corroborating the in vitro results. These results support the hypothesis that dogs are uniquely susceptible to cholestatic hepatotoxicity following administration of amcenestrant due to species-specific antagonism of FXR and highlight the value of in vitro liver spheroids to investigating mechanisms of toxicity and possible species differences.

Review on the Function, Substrate Affinity, and Potential Application of Bile Salt Hydrolase Originated from Probiotic Strains of Lactobacillus, Bifidobacterium, and Enterococcus

Bile salt hydrolase (BSH: EC.3.5.1.24) has been used as a biomarker for probiotics for an extended period. It is mostly present in the gut environment of vertebrates. Additionally, it influences the viability of probiotics. This biomarker is considered a promising nutritional supplement due to its unique ability to effectively address elevated blood cholesterol levels, a common issue in modern society. However, the commercialization of BSH has been limited by an incomplete understanding of the intestinal microbiota and the function of BSH. Hence, in this review, we aim to reveal the current advancements in BSH research and outline the necessary areas of investigation for future studies. The review highlights key findings related to the substrate affinity of BSH in probiotic bacteria and its BSH gene phylogeny that have been researched until today, suggesting further research regarding the differences in multiple BSH genes and corresponding differences in BSH affinity.

In Vitro-In Silico Models to Elucidate Mechanisms of Bile Acid Disposition and Cellular Aerobics in Human Hepatocytes

Understanding the kinetics of hepatic processes, such as bile acid (BA) handling and cellular aerobic metabolism, is crucial for advancing our knowledge of liver toxicity, particularly drug-induced cholestasis (DiCho). This article aimed to construct interpretable models with parameter estimations serving as reference values when investigating these cell metrics. Longitudinal datasets on BA disposition and oxygen consumption rates were collected using sandwich-cultured human hepatocytes. Chenodeoxycholic acid (CDCA), lithocholic acid (LCA), as well as their amidated and sulfate-conjugated metabolites were quantified with liquid chromatography-mass spectrometry. The bile salt export pump (BSEP) abundance was monitored with targeted proteomics and modelled for activity assessment. Oxygen consumption was measured using Seahorse XFp analyser. Ordinary differential equation-based models were solved in R. The basolateral uptake and efflux clearance of glycine-conjugated CDCA (GCDCA) were estimated at 1.22 µL/min/106 cells (RSE 14%) and 0.11 µL/min/106 cells (RSE 10%), respectively. The GCDCA clearance from canaliculi back to the medium was 2.22 nL/min/106 cells (RSE 17%), and the dissociation constant between (G)CDCA and FXR for regulating BSEP abundance was 25.73 nM (RSE 11%). Sulfation clearance for LCA was 0.19 µL/min/106 cells (RSE 11%). Model performance was further demonstrated by a maximum two-fold deviation of the 95% confidence boundaries from parameter estimates. These in vitro-in silico models provide a quantitative framework for exploring xenobiotic impacts on BA disposition, BSEP activity, and cellular aerobic metabolism in hepatocytes. Model simulations were consistent with reported in vivo data in progressive familial intrahepatic cholestasis type II patients.

Novel Cyclohexyl Amido Acid Antagonists of Lysophosphatidic Acid Type 1 Receptor for the Treatment of Pulmonary Fibrosis

Lysophosphatidic acid (LPA) is a phospholipid activating different biological functions by binding to G protein-coupled receptors (LPA1-6). Among these, the role of the LPA1 receptor in modulating fibrotic processes is well-known, making it a therapeutic target for pulmonary fibrosis and other fibrotic disorders. Herein we report the search for a new class of LPA1 antagonists for the oral treatment of idiopathic pulmonary fibrosis with a focus on hepatobiliary safety. Compound 7 excelled in in vitro and in vivo efficacy, showing significant efficacy both in PD studies and in a rodent lung fibrosis model, with a promising in vitro hepatic safety profile. However, in a dose range finding (DRF) toxicity study, compound 7 did not ensure safety regarding potential hepatobiliary toxicity, leading to its development being halted.

Molecular mechanisms in liver repair and regeneration: from physiology to therapeutics

Liver repair and regeneration are crucial physiological responses to hepatic injury and are orchestrated through intricate cellular and molecular networks. This review systematically delineates advancements in the field, emphasizing the essential roles played by diverse liver cell types. Their coordinated actions, supported by complex crosstalk within the liver microenvironment, are pivotal to enhancing regenerative outcomes. Recent molecular investigations have elucidated key signaling pathways involved in liver injury and regeneration. Viewed through the lens of metabolic reprogramming, these pathways highlight how shifts in glucose, lipid, and amino acid metabolism support the cellular functions essential for liver repair and regeneration. An analysis of regenerative variability across pathological states reveals how disease conditions influence these dynamics, guiding the development of novel therapeutic strategies and advanced techniques to enhance liver repair and regeneration. Bridging laboratory findings with practical applications, recent clinical trials highlight the potential of optimizing liver regeneration strategies. These trials offer valuable insights into the effectiveness of novel therapies and underscore significant progress in translational research. In conclusion, this review intricately links molecular insights to therapeutic frontiers, systematically charting the trajectory from fundamental physiological mechanisms to innovative clinical applications in liver repair and regeneration.

Changes in Protein Metabolism and Early Development of Sarcopenia in Mice With Cholestatic Liver Disease

BACKGROUND

Sarcopenia is a frequent complication of liver cirrhosis. Here, we chose a mouse model of cholestatic liver disease (CLD) to gain mechanistic insights into the development of sarcopenia from the earliest stages of chronic liver injury. Particular attention was paid to protein metabolism, metabolite profiles, and mediators of CLD-induced muscle wasting.

METHODS

Male C57BL/6 J mice underwent bile duct ligation (BDL), sham surgery, or served as untreated controls. The observation phase lasted from the preoperative stage to postoperative day 14. Metabolic cage experiments were performed to determine the nitrogen balance (N-BAL), nitrogen metabolite profiles, and total energy expenditure (TEE) using doubly labelled water. The fractional protein synthesis rate (FPSR) was assessed using 2H5-ring-phenylalanine. Plasma concentrations of inflammatory markers, metabolites, and enzymes associated with liver damage were investigated. Muscle strength and volume were assessed using a grip strength meter and MRI, respectively. Gene expression was analysed by real-time PCR.

RESULTS

BDL caused CLD with necroses and inflammation, increased bilirubin (p < 0.0001) and conjugated bile acids (p < 0.05), and reduced food intake (p < 0.0001) and body weight (p < 0.0001; each vs. sham). Compared to controls, BDL mice showed lower N-BAL (p < 0.05), reduced TEE (p < 0.01), and lower FPSR in the liver (p < 0.05) and quadriceps muscle (p < 0.001). Arginine was the only plasma amino acid that was diminished after BDL compared to controls and sham treatment (p < 0.0001). Reduced muscle strength was observed as early as d3/d4 after BDL (p < 0.001; vs. sham), while muscle volume decreased from d6 to d13 (p < 0.05). In quadriceps muscle, a lower nuclei-to-fibre ratio (p < 0.001) and elevated 1-methyl-histidine (1-MH) (p < 0.001) were detected, whereas 3-MH was increased in the urine of BDL mice (p < 0.001; each vs. sham). The quadriceps muscle of BDL mice contained higher mRNA levels of atrophy-associated genes (Trim63: p < 0.0001, Fbxo32: p < 0.01) and Mstn (p < 0.05), but lower levels of genes involved in mitochondrial function (Cpt-1b: p < 0.05, Pgc-1α: p < 0.01; each vs. sham). In the plasma of BDL mice, elevated protein levels of TNF receptor-1 (p < 0.0001) and HGF-1 (p < 0.05) were observed, while myostatin was diminished (p < 0.05; each vs. sham).

CONCLUSIONS

Sarcopenia occurs early in CLD and is a multicausal process. Relevant pathophysiologies include reduced protein synthesis, degradation of muscle proteins, arginine deficiency, a systemic pro-inflammatory and catabolic state, and muscle toxicity of bile acids. Consequently, the treatment of sarcopenia should focus both on eliminating the cause of the cholestasis and on symptomatic measures such as anti-inflammatory treatment, lowering the bile acid level, and targeted compensation of deficiencies.

HBM4EU E-waste study - An untargeted metabolomics approach to characterize metabolic changes during E-waste recycling

E-waste contains hazardous chemicals that may be a direct health risk for workers involved in recycling. We conducted an untargeted metabolomics analysis of urine samples collected from male e-waste processing workers to explore metabolic changes associated with chemical exposures in e-waste recycling in Belgium, Finland, Latvia, Luxembourg, the Netherlands, Poland, and Portugal. Questionnaire data and urine samples were obtained from workers involved in the processing of e-waste (sorting, dismantling, shredding, pre-processing, metal, and non-metal processing), as well as from controls with no known occupational exposure. Pre- and post-shift urine samples were collected and analysed using ultrahigh-performance liquid chromatography-mass spectrometry (UPLC-MS). A total of 32 endogenous urinary metabolites were annotated with a Variable Importance in Projection (VIP) above 2, indicating that e-waste recycling is mainly associated with changes in steroid hormone and neurotransmitter metabolism, energy metabolism, bile acid biosynthesis, and inflammation. The highest VIP was observed for dopamine-o-quinone, which is linked to Parkinson's disease. These and other changes in metabolism in workers employed in the processing of e-waste need further verification in targeted studies.

Altered bile acid and coproporphyrin-I disposition in patients with autosomal dominant polycystic kidney disease

AIMS

Serum, liver and urinary bile acids are increased, and hepatic transport protein levels are decreased in a non-clinical model of polycystic kidney disease. Similar changes in patients with autosomal dominant polycystic kidney disease (ADPKD) may predispose them to drug-induced liver injury (DILI) and hepatic drug-drug interactions (DDIs). Systemic coproporphyrin-I (CP-I), an endogenous biomarker for hepatic OATP1B function and MRP2 substrate, is used to evaluate OATP1B-mediated DDI risk in humans. In this clinical observational cohort-comparison study, bile acid profiles and CP-I concentrations in healthy volunteers and patients with ADPKD were compared.

METHODS

Serum and urine samples from healthy volunteers (n = 16) and patients with ADPKD (n = 8) were collected. Serum bile acids, and serum and urine CP-I concentrations, were quantified by ultra-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS).

RESULTS

Patients with ADPKD exhibited increased serum concentrations of total (1.3-fold) and taurine-conjugated (2.8-fold) bile acids compared to healthy volunteers. Specifically, serum concentrations of six bile acids known to be more hydrophobic/hepatotoxic (glycochenodeoxycholate, taurochenodeoxycholate, taurodeoxycholate, lithocholate, glycolithocholate and taurolithocholate) were increased (1.5-, 2.9-, 2.8-, 1.6-, 1.7- and 2.7-fold, respectively) in patients with ADPKD. Furthermore, serum CP-I concentrations were elevated and the renal clearance of CP-I was reduced in patients with ADPKD compared to healthy volunteers.

CONCLUSIONS

Increased exposure to bile acids may increase susceptibility to DILI in some patients with ADPKD. Furthermore, the observed increase in serum CP-I concentrations could be attributed, in part, to impaired OATP1B function in patients with ADPKD, which could increase the risk of DDIs involving OATP1B substrates compared to healthy volunteers.

Maternal Western Diet Programmes Bile Acid Dysregulation and Hepatic Fibrosis in Fetal and Juvenile Macaques

BACKGROUND AND AIMS

Maternal obesity increases the risk of the paediatric form of metabolic dysfunction-associated steatotic liver disease (MASLD), affecting up to 30% of youth, but the developmental origins remain poorly understood.

METHODS

Using a Japanese macaque model, we investigated the impact of maternal Western-style diet (mWSD) or chow diet followed by postweaning WSD (pwWSD) or chow diet focusing on bile acid (BA) homeostasis and hepatic fibrosis in livers from third-trimester fetuses and 3-year-old juvenile offspring.

RESULTS

Juveniles exposed to mWSD had increased hepatic collagen I/III content and stellate cell activation in portal regions. mWSD increased transcriptional signatures of FXR activation, while pwWSD impaired FXR pathway genes and increased liver BA content. Both mWSD and pwWSD increased serum BA concentrations. Notably, mWSD-exposed juvenile offspring had increased periportal CK19 expression and cholangiocyte gene expression supporting proliferation compared with maternal chow-exposed offspring. Fetuses exposed to mWSD had increased CK19 expression and hepatic BAs which correlated positively with periportal collagen deposition and negatively with markers of fetal oxygenation. In juvenile offspring, increased serum BAs correlated positively with hepatic oxidative stress and portal fibrosis without elevated liver enzymes.

CONCLUSIONS

mWSD is associated with hallmarks of paediatric MASLD including portal bile ductular reaction, portal fibrosis and dysregulated BA homeostasis. These conditions begin in utero and persist in juvenile offspring regardless of their postweaning diet. These findings implicate changes in BA metabolism that may drive developmental programming of MASLD in juvenile offspring beginning in utero.

Assessing the efficacy of farnesoid X receptor agonists in the management of metabolic dysfunction-associated steatotic liver disease: A systematic review and meta-analysis: Efficacy of Farnesoid X Receptor Agonists in Metabolic Dysfunction-associated Steatotic Liver Disease: Systematic Review and Meta-analysis

BACKGROUND AND AIMS

Several randomized clinical trials have been conducted assessing the potential efficacy of Farnesoid X receptor (FXR) agonists in patients with metabolic dysfunction-associated steatotic liver disease (MASLD). A comprehensive review and analysis were needed to evaluate the findings of these trials. Hence, this systematic review and meta-analysis aim to study the association between FXR agonists and hepatic outcomes in patients with MASLD.

METHODS

Systematic review and meta-analysis evaluating the efficacy of FXR agonists in 1,227 patients assigned to the FXR intervention group compared to 650 patients in the placebo group. Changes in liver enzymes and hepatic steatosis assessed by MRI-PDFF were evaluated.

RESULTS

FXR agonist use was associated with a significant reduction in levels of AST, (WMD= -4.51, 95% CI=[-8.39,-0.63], P=0.02); ALT (WMD= -13.02, 95% CI=[-17.85,-8.19], P<0.00001); GGT (WMD= -32.20, 95% CI=[-38.63,-25.98], P<0.00001); MRI-PDFF, (SMD= -1.14, 95% CI=[-1.92,-0.35], P=0.005). FXR agonists did not significantly affect ALP levels, (WMD= 25.04, 95% CI=[19.22,30.87], P<0.00001] CONCLUSION: Results show promising evidence supporting the efficacy of FXR agonists in reducing hepatic steatosis and biomarkers of hepatic injury such as ALT, AST, and GGT.

High leafy and root vegetables and high rice dietary patterns were associated with primary and secondary bile acid levels in the feces

Colorectal cancer has the second highest mortality among cancer sites worldwide, with increasing morbidity, high recurrence rates, and even poorer postoperative quality of life. Therefore, preventive strategies for colorectal cancer should be established. This study aimed to cross-sectionally explore dietary patterns affecting the intestinal metabolism of bile acids (BAs), a risk factor for colorectal cancer, in young Japanese women. We collected fecal samples for intestinal microbiota and BA analysis. We used the Bristol scale to determine 1-week defecation status. Moreover, the brief-type self-administered diet history questionnaire was used for habitual dietary intake status. Reduced-rank regression analysis revealed dietary patterns related to fecal BA levels. The relationship between dietary patterns and fecal BA levels was adjusted for defecation status and intestinal microbiota variables using analysis of covariance. Reduced-rank regression analysis generated two dietary pattern scores related to fecal BA levels. First, the score was associated with a greater intake of leafy and root vegetables, and higher values were associated with greater fecal cholic and chenodeoxycholic acid levels and lower deoxycholic and lithocholic acid levels. Second, the score was associated with greater rice intake and lower Western sweets, pork, beef, and egg intake, and higher values were associated with lower deoxycholic and lithocholic acid levels. These relationships remained after adjusting for intestinal microbiota and defecation status variables.

Assessment of the Scolicidal Effect of Bile: An Ex Vivo Study

Background

Approximately 25% of hepatic hydatid cysts rupture into the biliary tract. The precise effect of bile within the cyst on protoscoleces remains unclear. We aimed to elucidate the effect of bile on protoscoleces.

Methods

The contents of hydatid cysts from the livers of three sheep were aspirated under sterile conditions. The aspirated contents were divided into 50 separate Eppendorf tubes (5 cc). Samples from each tube were stained with 0.1% eosin Y. Pink stained protoscoleces were considered dead under light microscopy (×100). A total of 100 protoscoleces were counted in each sample, and the number of live and dead protoscoleces was recorded. The tubes were randomly divided into five groups. Group 1 served as the control, Group 2 received normal saline (NS), Group 3, received hypertonic saline, Group 4 received bile, and Group 4 received diluted bile. The number of live and dead protoscoleces was recorded at the end of the first and second hours.

Results

Compared to the initial count of live protoscoleces, the number of live protoscoleces increased at hours 1 and 2 in Groups 2 and 4. No live protoscoleces remained at hours 1 and 2 in Group 3. There was no significant change in Group 5. When compared to the control group, a significant increase in viability was observed only in Group 4 (P=0.001).

Conclusion

Bile of sheep does not exhibit scolicidal effects; rather, it positively affects protoscoleces by increasing viability.

Liver metabolism in human MASLD: A review of recent advancements using human tissue metabolomics

Global incidence of Metabolic dysfunction-Associated Steatotic Liver Disease (MASLD) is on the rise while treatments remain elusive. MASLD is a disease of dysregulated systemic and hepatic metabolism. Current understanding of disease pathophysiology as it relates to metabolome changes largely comes from studies on animal models and human plasma. However, human tissue data are crucial for transitioning from mechanisms to clinical therapies. The close relationship between MASLD and comorbidities like obesity, type 2 diabetes and dyslipidemia make it difficult to determine the contribution from liver disease itself. Here, we review recent metabolomics studies in liver tissue from human MASLD patients, which have predominately focused on lipid metabolism, but also include bile acid, tricarboxylic acid (TCA) cycle, and branched chain amino acid (BCAA) metabolism. Several clinical trials are underway to target various of these lipid-related pathways in MASLD. Although only the β-selective thyroid hormone receptor agonist resmetirom has so far been approved for use, many metabolism-targeting pharmaceuticals show promising results for halting disease progression, if not promoting outright reversal. Ultimately, the scarcity of human tissue data and the variability of confounding factors, like obesity, within and between cohorts are impediments to the pathophysiological understanding required for efficient development of metabolic treatments.

Thoracobiliary Fistula Complications Following Concomitant Diaphragm and Liver Injury

INTRODUCTION

Thoracobiliary fistula (TBF) is a rare and highly morbid complication of hepatic trauma. There is a paucity of literature regarding incidence, disease course, and treatment. This study identifies etiologic factors and outcome patterns in patients at risk for TBF.

METHODS

A retrospective review of patients presenting with concern for trans-diaphragmatic bile leak over an 8-y period was performed at an urban level 1 trauma center. Early postinjury deaths were excluded. Records were reviewed for presence of a delayed bile leak. Patient characteristics with concern for (No-TBF) and confirmed fistula (TBF) were compared using Fisher's exact and Mann-Whitney U-tests. The disease courses of patients with TBF were further examined.

RESULTS

Over the study period, 118 patients with concomitant right diaphragm and liver injury were reviewed, of these 114 patients (96.6%) survived longer than 72 h. Four patients developed TBF (3.5%). Patients with TBF were younger (P = 0.01) and had trends toward less frequent liver repair (P = 0.061) or concomitant liver and diaphragm repair (P = 0.061). Video-assisted thoracoscopic surgery for retained hemothorax was associated with increased risk of TBF (P = 0.005). Patients with TBF were significantly more likely to develop infectious complications such as sepsis, pneumonia, or complicated parapneumonic effusion (P < 0.001). Treatment of TBF included endoscopic retrograde cholangiopancreatography, sphincterotomy, and stent placement.

CONCLUSIONS

Although TBF incidence is low, patients with concomitant right hemidiaphragm and liver trauma may be at higher risk for developing TBF without prompt and definitive operative intervention. This injury is characterized by infectious complications requiring further interventional treatment and monitoring.

Conjugated bile acids alleviate acute pancreatitis through inhibition of TGR5 and NLRP3 mediated inflammation

INTRODUCTION

Severe acute pancreatitis (SAP) is a crucial gastrointestinal disease characterized by systemic inflammatory responses and persistent multiple organ failure. The role of bile acids (BAs) in diverse inflammatory diseases is increasingly recognized as crucial, but the underlying role of BA conjugation remains elusive.

OBJECTIVES

Our study aim to investigate the potential role of conjugated bile acids in SAP and reveal the molecular mechanisms underlying its regulatory effects. We hypothesized that taurochenodeoxycholic acid (TCDCA) and glycochenodeoxycholic acid (GCDCA) could protect SAP through inhibiting the activation of NLRP3 inflammasomes via the TGR5 pathway in macrophages.

METHODS

To test our hypothesis, we used BA-CoA: amino acid N-acyltransferase knockout (Baat-/-) mice and established SAP mouse models using caerulein- and sodium taurocholate- induced. We utilized a range of methods, including pathology sections, qRT-PCR, immunofluorescence, Western blotting, and ELISA, to identify the mechanisms of regulation.

RESULTS

BA-CoA: Amino acid N-acyltransferase knockout (Baat-/-) mice significantly exacerbated pancreatitis by increasing pancreatic and systemic inflammatory responses and pancreatic damage in SAP mouse models. Moreover, the serum TCDCA levels in Baat-/- mice were lower than those in wild-type (WT) mice with or without SAP, and GCDCA and TCDCA showed stronger anti-inflammatory effects than chenodeoxycholic acid (CDCA) in vitro. TCDCA treatment alleviated SAP in a Takeda G protein-coupled receptor 5 and NOD-like receptor family, pyrin domain containing 3-dependent manner in vivo. Reinforcing our conclusions from the mouse study, clinical SAP patients exhibited decreased serum content of conjugated BAs, especially GCDCA, which was inversely correlated with the severity of systemic inflammatory responses.

CONCLUSION

Conjugated bile acids significantly inhibit NLRP3 inflammasome activation by activating TGR5 pathway, thereby alleviating pancreatic immunopathology. The results provide new insights into the variability of clinical outcomes and paves the way for developing more effective therapeutic interventions for AP.

Elevated Bile Acids Induce Circadian Rhythm Sleep Disorders in Chronic Liver Diseases

BACKGROUND & AIMS

Sleep disorders (SDs) are common in chronic liver diseases (CLDs). Some SDs arise from impaired internal clock and are, hence, circadian rhythm SDs (CRSDs). Bile acids (BAs), whose levels are increased in many CLDs, reciprocally interact with circadian rhythm. This study explores the mechanisms underlying CRSDs in CLDs and novel therapies.

METHODS

We monitored the sleep of patients with CLD using actigraphic watch and established male mouse cholemia models by feeding with BA or bile duct ligation. Sleep-wake cycle and circadian rhythm were analyzed by electroencephalogram-electromyography and locomotor wheel-running experiments.

RESULTS

Patients with CLD showed CRSD-like phenotypes including increased night activity and early awakening, which were strongly correlated with increased BA levels (ie, cholemia). CRSDs, including shortened circadian period, were recapitulated in 2 cholemic mouse models. Mechanistically, elevated BAs in the suprachiasmatic nucleus (SCN) activated BA receptor Takeda G protein-coupled receptor 5 (Tgr5), which, in turn, increased the level and phosphorylation of Period2 (Per2), a master rhythm regulator, through extracellular signal-regulated kinase (Erk) and casein kinase 1ε (CK1ε). Per2 phosphorylation inhibited its nuclear import, which would release its transcriptional inhibition and expedite the circadian cycle. Cholemia also blunted the light entrainment response and light-induced phase change of SCN mediated by the neurons expressing gastrin releasing peptide through Tgr5-Per2 axis. BA sequestrant or CK1 inhibitor reversed the CRSDs in cholemic mice by restoring Per2 distribution.

CONCLUSIONS

Cholemia is a major risk factor for CRSDs in CLDs and, hence, a promising target in future clinical study.

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.

The correlation between blood lipids and intrahepatic cholestasis syndrome during pregnancy

BACKGROUND

To analyse changes in lipid levels during the development of intrahepatic cholestasis of pregnancy (ICP) and identify new biomarkers for predicting ICP.

METHODS

A retrospective case-control study was conducted to analyse 473 pregnant women who underwent regular prenatal examinations and delivered at the Women and Children's Hospital, School of Medicine, Xiamen University, between June 2020 and June 2023, including 269 normal pregnancy controls and 204 pregnant women with cholestasis.

RESULTS

Patients with ICP with gestational diabetes mellitus (GDM) have lower high-density lipoprotein (HDL) levels than in those without GDM. Total bile acid (TBA) levels were significantly higher in pregnant women with GDM than those without. The apolipoprotein A (APOA) level was lower in patients with ICP and hypothyroidism than those without hypothyroidism. TBA levels were significantly higher in pregnant women with hypothyroidism than those without. Triglyceride (TG) levels were significantly higher in patients with preeclampsia (PE) than those without. HDL and APOA levels were lower in women with ICP complicated by preterm delivery than those with normal delivery. The AUC (area under the curve) of the differential diagnosis of cholestasis of pregnancy for the APOA/APOB (apolipoprotein B) ratio was 0.727, with a sensitivity of 85.9% and specificity of 47.5%.

CONCLUSIONS

The results suggested that dyslipidaemia is associated with an increased risk of ICP and its complications. The timely detection of blood lipid and bile acid levels can assist in the diagnosis of ICP and effectively prevent ICP and other complications.

Hepatic bile acid accretion correlates with cholestatic liver injury and therapeutic response in Cyp2c70 knockout mice with a humanized bile acid composition

Cyp2c70 knockout (KO) mice lack the liver enzyme responsible for synthesis of 6-hydroxylated muricholate bile acid species and possess a more hydrophobic human-like bile acid composition. Cyp2c70 KO mice develop cholestatic liver injury that can be prevented by the administration of an ileal bile acid transporter (IBAT) inhibitor. In this study, we investigated the potential of an ileal bile acid transporter (IBAT) inhibitor (SC-435) and steroidal farnesoid X receptor (FXR) agonist (cilofexor) to modulate established hepatobiliary injury and the consequent relationship of intrahepatic bile acid content and hydrophobicity to the cholestatic liver injury phenotype. Oral administration of SC-435, cilofexor, or combined treatment for 2 wk markedly reduced serum markers of liver injury and improved histological and gene expression markers of fibrosis, liver inflammation, and ductular reaction in male and female Cyp2c70 KO mice, with the greatest benefit in the combination treatment group. The IBAT inhibitor and FXR agonist significantly reduced intrahepatic bile acid content but not hepatic bile acid pool hydrophobicity, and markers of liver injury were strongly correlated with intrahepatic total bile acid and taurochenodeoxycholic acid accretion. Biomarkers of liver injury increased linearly with similar hepatic thresholds for pathological accretion of hydrophobic bile acids in male and female Cyp2c70 KO mice. These findings further support targeting intrahepatic bile acid retention as a component of treatments for cholestatic liver disease.NEW & NOTEWORTHY Bile acids are implicated as a common contributor to the pathogenesis and progression of cholestatic liver disease. Using a mouse model with a humanized bile acid composition, we demonstrated that mono and combination therapy using an IBAT inhibitor and FXR nonsteroidal agonist were effective at reducing hepatic bile acid accretion and reversing liver injury, without reducing hepatic bile acid hydrophobicity. The findings support the concept of a therapeutically tractable threshold for bile acid-induced liver injury.

Effects of therapeutically approved individual bile acids on the development of metabolic dysfunction-associated steatohepatitis a low bile acid mouse model

Bile acid (BA) signaling dysregulation is an important etiology for the development of metabolic dysfunction-associated steatotic liver disease (MASLD). As diverse signaling molecules synthesized in the liver by pathways initiated with CYP7A1 and CYP27A1, BAs are endogenous modulators of farnesoid x receptor (FXR). FXR activation is crucial in maintaining BA homeostasis, regulating lipid metabolism, and suppressing inflammation. Additionally, BAs interact with membrane receptors and gut microbiota to regulate energy expenditure and intestinal health. Complex modulation of BAs in vivo and the lack of suitable animal models impede our understanding of the functions of individual BAs, especially during MASLD development. Previously, we determined that acute feeding of individual BAs differentially affects lipid, inflammation, and oxidative stress pathways in a low-BA mouse model, Cyp7a1/Cyp27a1 double knockout (DKO) mice. Currently, we investigated to what degree cholic acid (CA), deoxycholic acid (DCA), or ursodeoxycholic acid (UDCA) at physiological concentrations impact MASLD development in DKO mice. The results showed that these 3 BAs varied in the ability to activate hepatic and intestinal FXR, disrupt lipid homeostasis, and modulate inflammation and fibrosis. Additionally, UDCA activated intestinal FXR in these low-BA mice. Significant alterations in lipid uptake and metabolism in DKO mice following CA and DCA feeding indicate differences in cholesterol and lipid handling across genotypes. Overall, the DKO were less susceptible to weight gain, but more susceptible to MASH diet induced inflammation and fibrosis on CA and DCA supplements, whereas WT mice were more vulnerable to CA-induced fibrosis on the control diet.

Regulation of Mitochondrial and Peroxisomal Metabolism in Female Obesity and Type 2 Diabetes

Obesity and type 2 diabetes (T2D) are widespread metabolic disorders that significantly impact global health today, affecting approximately 17% of adults worldwide with obesity and 9.3% with T2D. Both conditions are closely linked to disruptions in lipid metabolism, where peroxisomes play a pivotal role. Mitochondria and peroxisomes are vital organelles responsible for lipid and energy regulation, including the β-oxidation and oxidation of very long-chain fatty acids (VLCFAs), cholesterol biosynthesis, and bile acid metabolism. These processes are significantly influenced by estrogens, highlighting the interplay between these organelles' function and hormonal regulation in the development and progression of metabolic diseases, such as obesity, metabolic dysfunction-associated fatty liver disease (MAFLD), and T2D. Estrogens modulate lipid metabolism through interactions with nuclear receptors, like peroxisome proliferator-activated receptors (PPARs), which are crucial for maintaining metabolic balance. Estrogen deficiency, such as in postmenopausal women, impairs PPAR regulation, leading to lipid accumulation and increased risk of metabolic disorders. The disruption of peroxisomal-mitochondrial function and estrogen regulation exacerbates lipid imbalances, contributing to insulin resistance and ROS accumulation. This review emphasizes the critical role of these organelles and estrogens in lipid metabolism and their implications for metabolic health, suggesting that therapeutic strategies, including hormone replacement therapy, may offer potential benefits in treating and preventing metabolic diseases.

Correlation of bilirubin and toxic bile acids in critically ill patients with cholestatic liver dysfunction and adsorber application

Bilirubin is one of the most frequently used laboratory values to monitor critically ill patients with cholestatic liver dysfunction. Besides bilirubin, toxic bile acids (TBAs), which may cause severe organ damage, are typically elevated. A correlation between both parameters seems plausible, but data are lacking. The aim was to investigate whether there is a correlation between bilirubin and TBAs in patients' blood and whether a compareable reduction can be observed during the use of the adsorber CytoSorb (CS). As part of the Cyto-SOLVE study (NCT04913298), 16 critically ill patients with cholestatic liver dysfunction, bilirubin concentration > 10 mg/dl, continuous kidney replacement therapy and CS-application were investigated. Bilirubin and TBA concentrations were measured from arterial blood at defined time points (before start, after 6 and 12 h). Relative reduction (RR) was calculated using the formula[Formula: see text]. A moderate to high correlation between bilirubin and TBA concentration at all defined timepoints (rstart=0.64, p = 0.008; r6h = 0.85, p < 0.001, r12h = 0.72, p = 0.002) was observed. In the first six hours of CS-application, a significant elimination of TBA (median TBA: 30.8→20.1µmol/l, p < 0.001) and bilirubin (median bilirubin: 17.1→11.9 mg/dl, p < 0.001) was observed. The median RR after 6 h was 26.1% and 39.8% for bilirubin and TBA, respectively. No further reduction was observed after 12 h (RRbilirubin: - 0.6%, RRTBA: 1.8%). There was an at least moderate correlation between bilirubin and TBA in patients with cholestatic liver dysfunction. Therefore, bilirubin seems to be a suitable surrogate parameter for TBA elimination during CytoSorb application.

Proteinuria is a clinical characteristic of intrahepatic cholestasis of pregnancy but it is not a marker of severity: A retrospective cohort study

OBJECTIVES

To determine the prevalence of proteinuria in patients diagnosed with intrahepatic cholestasis of pregnancy (IHCP), and the association between the presence of proteinuria and adverse pregnancy outcomes.

METHODS

This was a retrospective cohort study. The study included all pregnant patients between July 2014 and January 2022, at gestational age > 24weeks who had been diagnosed with IHCP and had completed a 24-hour protein collection. High order multifetal gestations were excluded. Patients were divided into 3 groups:1. IHCP without proteinuria (Non-proteinuric group);2. IHCP with proteinuria and normal blood pressure (Isolated proteinuria group), and 3. IHCP with proteinuria and elevated blood pressure (IHCP with preeclampsia (PET)). Primary outcome was defined as a composite maternal-fetal outcome including: preterm labor <34 weeks, arterial cord blood ph<7.1, rate of Cesarean delivery due to non-reassuring fetal monitoring. Parametric and non-parametric statistical methods were used for analysis.

RESULTS

A total of 272 met all inclusion criteria and were included, 94 patients (34.5%) had proteinuria; of them, 67 (24.6%) had isolated proteinuria and 27 (9.9%) had PET. Demographic parameters were comparable among the groups. Patients with PET had higher rates of in-vitro fertilization (IVF) treatments, twin gestation and elevated serum creatinine and urea levels. The rate of composite adverse pregnancy outcome was higher in patients with PET compared with patients with and without proteinuria (14/27 (51.9%) vs. 18/67 (26.9%) vs. 49/178 (27.5%), respectively, p = 0.03).

CONCLUSIONS

Approximately 35% of patients with IHCP have proteinuria. The presence of PET, rather than isolated proteinuria, is associated with adverse pregnancy outcome.

Metabolomics analysis of patients with Schistosoma japonicum infection based on UPLC-MS method

BACKGROUND

Schistosomiasis is still one of the most serious parasitic diseases. Evidence showed that the metabolite profile in serum can potentially act as a marker for parasitic disease diagnosis and evaluate disease progression and prognosis. However, the serum metabolome in patients with Schistosoma japonicum infection is not well defined. In this study, we investigated the metabolite profiles of patients with chronic and with advanced S. japonicum infection.

METHODS

The sera of 33 chronic S. japonicum patients, 15 patients with advanced schistosomiasis and 17 healthy volunteers were collected. Samples were extracted for metabolites and analyzed with ultra-performance liquid chromatography-mass spectrometry (UPLC-MS).

RESULTS

We observed significant differences in metabolite profiles in positive and negative ion modes between patients with advanced and chronic S. japonicum infection. In patients with chronic S. japonicum infection, 199 metabolites were significantly upregulated while 207 metabolites were downregulated in advanced infection. These differential metabolites were mainly concentrated in steroid hormone biosynthesis, cholesterol metabolism and bile secretion pathways. We also found that certain bile acid levels were significantly upregulated in the progression from chronic to advanced S. japonicum infection. In receiver operator characteristic (ROC) analysis, we identified three metabolites with area under the curve (AUC) > 0.8, including glycocholic (GCA), glycochenodeoxycholate (GCDCA) and taurochenodeoxycholic acid (TCDCA) concentrated in cholesterol metabolism, biliary secretion and primary bile acid biosynthesis.

CONCLUSIONS

This study provides evidence that GCA, GCDCA and TCDCA can potentially act as novel metabolite biomarkers to distinguish patients in different stages of S. japonicum infection. This study will contribute to the understanding of the metabolite mechanisms of the transition from chronic to advanced S. japonicum infection, although more studies are needed to validate this potential role and explore the underlying mechanisms.

Bile acid-gut microbiota imbalance in cholestasis and its long-term effect in mice

Cholestasis is a common morbid state that may occur in different phases; however, a comprehensive evaluation of the long-term effect post-recovery is still lacking. In the hepatic cholestasis mouse model, which was induced by a temporary complete blockage of the bile duct, the stasis of bile acids and liver damage typically recovered within a short period. However, we found that the temporary hepatic cholestasis had a long-term effect on gut microbiota dysbiosis, including overgrowth of small intestinal bacteria, decreased diversity of the gut microbiota, and an overall imbalance in its composition accompanied by an elevated inflammation level. Additionally, we observed an increase in Escherichia-Shigella (represented by ASV136078), rich in virulence factors, in both small and large intestines following cholestasis. To confirm the causal role of dysregulated gut microbiota in promoting hepatic inflammation and injury, we conducted gut microbiota transplantation into germ-free mice. We found that recipient mice transplanted with feces from cholestasis mice exhibited liver inflammation, damage, and accumulation of hepatic bile acids. In conclusion, our study demonstrates that cholestasis disrupts the overall load and structural composition of the gut microbiota in mice, and these adverse effects persist after recovery from cholestatic liver injury. This finding suggests the importance of monitoring the structural composition of the gut microbiota in patients with cholestasis and during their recovery.

IMPORTANCE

Our pre-clinical study using a mouse model of cholestasis underscores that cholestasis not only disrupts the equilibrium and structural configuration of the gut microbiota but also emphasizes the persistence of these adverse effects even after bile stasis restoration. This suggests the need of monitoring and initiating interventions for gut microbiota structural restoration in patients with cholestasis during and after recovery. We believe that our study contributes to novel and better understanding of the intricate interplay among bile acid homeostasis, gut microbiota, and cholestasis-associated complications. Our pre-clinical findings may provide implications for the clinical management of patients with cholestasis.

Bile Acids as Emerging Players at the Intersection of Steatotic Liver Disease and Cardiovascular Diseases

Affecting approximately 25% of the global population, steatotic liver disease (SLD) poses a significant health concern. SLD ranges from simple steatosis to metabolic dysfunction-associated steatohepatitis and fibrosis with a risk of severe liver complications such as cirrhosis and hepatocellular carcinoma. SLD is associated with obesity, atherogenic dyslipidaemia, and insulin resistance, increasing cardiovascular risks. As such, identifying SLD is vital for cardiovascular disease (CVD) prevention and treatment. Bile acids (BAs) have critical roles in lipid digestion and are signalling molecules regulating glucose and lipid metabolism and influencing gut microbiota balance. BAs have been identified as critical mediators in cardiovascular health, influencing vascular tone, cholesterol homeostasis, and inflammatory responses. The cardio-protective or harmful effects of BAs depend on their concentration and composition in circulation. The effects of certain BAs occur through the activation of a group of receptors, which reduce atherosclerosis and modulate cardiac functions. Thus, manipulating BA receptors could offer new avenues for treating not only liver diseases but also CVDs linked to metabolic dysfunctions. In conclusion, this review discusses the intricate interplay between BAs, metabolic pathways, and hepatic and extrahepatic diseases. We also highlight the necessity for further research to improve our understanding of how modifying BA characteristics affects or ameliorates disease.

The endocrine FGFs axis: A systemic anti-fibrotic response that could prevent pulmonary fibrogenesis?

Idiopathic pulmonary fibrosis (IPF) is a progressive and fatal disease for which therapeutic options are limited, with an unmet need to identify new therapeutic targets. IPF is thought to be the consequence of repeated microlesions of the alveolar epithelium, leading to aberrant epithelial-mesenchymal communication and the accumulation of extracellular matrix proteins. The reactivation of developmental pathways, such as Fibroblast Growth Factors (FGFs), is a well-described mechanism during lung fibrogenesis. Secreted FGFs with local paracrine effects can either exert an anti-fibrotic or a pro-fibrotic action during this pathological process through their FGF receptors (FGFRs) and heparan sulfate residues as co-receptors. Among FGFs, endocrine FGFs (FGF29, FGF21, and FGF23) play a central role in the control of metabolism and tissue homeostasis. They are characterized by a low affinity for heparan sulfate, present in the cell vicinity, allowing them to have endocrine activity. Nevertheless, their interaction with FGFRs requires the presence of mandatory co-receptors, alpha and beta Klotho proteins (KLA and KLB). Endocrine FGFs are of growing interest for their anti-fibrotic action during liver, kidney, or myocardial fibrosis. Innovative therapies based on FGF19 or FGF21 analogs are currently being studied in humans during liver fibrosis. Recent data report a similar anti-fibrotic action of endocrine FGFs in the lung, suggesting a systemic regulation of the pulmonary fibrotic process. In this review, we summarize the current knowledge on the protective effect of endocrine FGFs during the fibrotic processes, with a focus on pulmonary fibrosis.

Drug reactive metabolite-induced hepatotoxicity: a comprehensive review

Nowadays, drug-induced liver toxicity (DILT) is one of the main contributing factors to severe liver disease. In the United States (US) alone, DILT is the cause of more than 50% of instances of acute liver failure. Prescription or over-the-counter drugs, xenobiotics, and herbal and nutritional supplements can cause DILT and could produce anomalies in hepatic function tests. Some drugs induce hepatotoxicity directly, and others induce it indirectly (i. e. through their toxic or reactive metabolites). Currently, the United States Food and Drug Administration (US FDA) has issued black box warnings for about 1279 drugs due to their hepatotoxicity. When we analyzed their mechanism in inducing hepatotoxicity, we found nearly 18 drugs causing hepatotoxicity by their toxic metabolites. In this review, we attempted to highlight the well-known drugs that induce hepatotoxicity indirectly through their toxic metabolites including the enzymes involved in the formation of these metabolites. The Cytochrome P-450 (CYP), Hypoxanthine phosphoribosyltransferase 1, Alcohol oxidase, Uridine diphosphate (UDP)-glucuronosyltransferases, Xanthine dehydrogenase, Purine-nucleoside phosphorylase, Xanthine oxidase, Thiopurine S-methyltransferase, Inosine-5'-monophosphate dehydrogenase, and aldehyde dehydrogenase are involving in the formation of toxic metabolites. The metabolic reactions and enzymes discussed in this review help toxicologists, pharmacologists, and chemists to design and develop hepatotoxicity-free pharmaceutical products containing the inhibitors of these enzymes to reduce hepatotoxicity and improve human health.

Ling-Gui-Zhu-Gan decoction ameliorates nonalcoholic fatty liver disease via modulating the gut microbiota

Numerous studies have supported that nonalcoholic fatty liver disease (NAFLD) is highly associated with gut microbiota dysbiosis. Ling-Gui-Zhu-Gan decoction (LG) has been clinically used to treat NAFLD, but the underlying mechanism remains unknown. This study investigated the therapeutic effect and mechanisms of LG in mice with NAFLD induced by a high-fat diet (HD). An HD-induced NAFLD mice model was established to evaluate the efficacy of LG followed by biochemical and histopathological analysis. Metagenomics, metabolomics, and transcriptomics were used to explore the structure and metabolism of the gut microbiota. LG significantly improved hepatic function and decreased lipid droplet accumulation in HD-induced NAFLD mice. LG reversed the structure of the gut microbiota that is damaged by HD and improved intestinal barrier function. Meanwhile, the LG group showed a lower total blood bile acids (BAs) concentration, a shifted BAs composition, and a higher fecal short-chain fatty acids (SCFAs) concentration. Furthermore, LG could regulate the hepatic expression of genes associated with the primary BAs biosynthesis pathway and peroxisome proliferator-activated receptor (PPAR) signaling pathway. Our study suggested that LG could ameliorate NAFLD by altering the structure and metabolism of gut microbiota, while BAs and SCFAs are considered possible mediating substances.

IMPORTANCE

Until now, there has still been no study on the gut microbiota and metabolomics of Ling-Gui-Zhu-Gan decoction (LG) in nonalcoholic fatty liver disease (NAFLD) mouse models. Our study is the first to report on the reshaping of the structure and metabolism of the gut microbiota by LG, as well as explore the potential mechanism underlying the improvement of NAFLD. Specifically, our study demonstrates the potential of gut microbial-derived short-chain fatty acids (SCFAs) and blood bile acids (BAs) as mediators of LG therapy for NAFLD in animal models. Based on the results of transcriptomics, we further verified that LG attenuates NAFLD by restoring the metabolic disorder of BAs via the up-regulation of Fgf15/FXR in the ileum and down-regulation of CYP7A1/FXR in the liver. LG also reduces lipogenesis in NAFLD mice by mediating the peroxisome proliferator-activated receptor (PPAR) signaling pathway, which then contributes to reducing hepatic inflammation and improving intestinal barrier function to treat NAFLD.

Characterization of individual bile acids in vivo utilizing a novel low bile acid mouse model

Bile acids (BAs) are signaling molecules synthesized in the liver initially by CYP7A1 and CYP27A1 in the classical and alternative pathways, respectively. BAs are essential for cholesterol clearance, intestinal absorption of lipids, and endogenous modulators of farnesoid x receptor (FXR). FXR is critical in maintaining BA homeostasis and gut-liver crosstalk. Complex reactions in vivo and the lack of suitable animal models impede our understanding of the functions of individual BAs. In this study, we characterized the in vivo effects of three-day feeding of cholic acid (CA), deoxycholic acid (DCA), or ursodeoxycholic acid (UDCA) at physiological/non-hepatotoxic concentrations in a novel low-BA mouse model (Cyp7a1-/-/Cyp27a1-/-, DKO). Liver injury, BA levels and composition and BA signaling by the FXR-fibroblast growth factor 15 (FGF15) axis were determined. Overall, higher basal inflammation and altered lipid metabolism in DKO mice might be associated with low BAs. CA, DCA, and UDCA feeding activated FXR signals with tissue specificity. Dietary CA and DCA similarly altered tissue BA profiles to be less hydrophobic, while UDCA promoted a more hydrophobic tissue BA pool with the profiles shifted toward non-12α-OH BAs and secondary BAs. However, UDCA did not offer any overt protective effects as expected. These findings allow us to determine the precise effects of individual BAs in vivo on BA-FXR signaling and overall BA homeostasis in liver physiology and pathologies.

Increased intestinal bile acid absorption contributes to age-related cognitive impairment

Cognitive impairment in the elderly is associated with alterations in bile acid (BA) metabolism. In this study, we observe elevated levels of serum conjugated primary bile acids (CPBAs) and ammonia in elderly individuals, mild cognitive impairment, Alzheimer's disease, and aging rodents, with a more pronounced change in females. These changes are correlated with increased expression of the ileal apical sodium-bile acid transporter (ASBT), hippocampal synapse loss, and elevated brain CPBA and ammonia levels in rodents. In vitro experiments confirm that a CPBA, taurocholic acid, and ammonia induced synaptic loss. Manipulating intestinal BA transport using ASBT activators or inhibitors demonstrates the impact on brain CPBA and ammonia levels as well as cognitive decline in rodents. Additionally, administration of an intestinal BA sequestrant, cholestyramine, alleviates cognitive impairment, normalizing CPBAs and ammonia in aging mice. These findings highlight the potential of targeting intestinal BA absorption as a therapeutic strategy for age-related cognitive impairment.

Perturbations in human bile acid profiles following drug-induced liver injury investigated using semitargeted high-resolution mass spectrometry

RATIONALE

Acetaminophen (APAP) overdose is the leading cause of acute liver failure (ALF) in North America. To investigate the effect of drug-induced liver injury (DILI) on circulating bile acid (BA) profiles, serum from ALF patients and healthy controls were analyzed using a semitargeted high-resolution mass spectrometry approach to measure BAs in their unconjugated and amidated forms and their glucuronide and sulfate conjugates.

METHODS

Human serum samples from 20 healthy volunteers and 34 ALF patients were combined with deuterated BAs and extracted, prior to liquid chromatography high-resolution tandem mass spectrometry analysis. A mix of 46 standards helped assign 26 BAs in human serum by accurate mass and retention time matching. Moreover, other isomers of unconjugated and amidated BAs, as well as glucuronide and sulfate conjugates, were assigned by accurate mass filtering. In vitro incubations of standard BAs provided increased information for certain peaks of interest.

RESULTS

A total of 275 BA metabolites, with confirmed or putative assignments, were measured in human serum samples. APAP overdose significantly influenced the levels of most BAs, promoting glycine conjugation, and, to a lesser extent, taurine conjugation. When patient outcome was considered, 11 BAs were altered significantly, including multiple sulfated species. Although many of the BAs measured did not have exact structures assigned, several putatively identified BAs of interest were further characterized using in vitro incubations.

CONCLUSION

An optimized chromatographic separation tailored to BAs of ranging polarities was combined with accurate mass measurements to investigate the effect that DILI has on their complex profiles and metabolism to a much wider extent than previously possible. The analysis of complex BA profiles enabled in-depth analysis of the BA metabolism perturbations in ALF, including certain metabolites related to patient outcomes.

Interplay Between Drug-Induced Liver Injury and Gut Microbiota: A Comprehensive Overview

Drug-induced liver injury is a prevalent severe adverse event in clinical settings, leading to increased medical burdens for patients and presenting challenges for the development and commercialization of novel pharmaceuticals. Research has revealed a close association between gut microbiota and drug-induced liver injury in recent years. However, there has yet to be a consensus on the specific mechanism by which gut microbiota is involved in drug-induced liver injury. Gut microbiota may contribute to drug-induced liver injury by increasing intestinal permeability, disrupting intestinal metabolite homeostasis, and promoting inflammation and oxidative stress. Alterations in gut microbiota were found in drug-induced liver injury caused by antibiotics, psychotropic drugs, acetaminophen, antituberculosis drugs, and antithyroid drugs. Specific gut microbiota and their abundance are associated closely with the severity of drug-induced liver injury. Therefore, gut microbiota is expected to be a new target for the treatment of drug-induced liver injury. This review focuses on the association of gut microbiota with common hepatotoxic drugs and the potential mechanisms by which gut microbiota may contribute to the pathogenesis of drug-induced liver injury, providing a more comprehensive reference for the interaction between drug-induced liver injury and gut microbiota.

Navigating the liver landscape: upcoming pharmacotherapies for primary sclerosing cholangitis

INTRODUCTION

Primary sclerosing cholangitis (PSC) is a bile duct disorder characterized by ductular reaction, hepatic inflammation, and liver fibrosis. The pathogenesis of PSC is still undefined, and treatment options for patients are limited. Previous clinical trials evaluated drug candidates targeting various cellular functions and pathways, such as bile acid signaling and absorption, gut bacteria and permeability, and lipid metabolisms. However, most of phase III clinical trials for PSC were disappointing, except vancomycin therapy, and there are still no established medications for PSC with efficacy and safety confirmed by phase IV clinical trials.

AREAS COVERED

This review summarizes the currently ongoing or completed clinical studies for PSC, which are phase II or further, and discusses therapeutic targets and strategies, limitations, and future directions and possibilities of PSC treatments. A literature search was conducted in PubMed and ClinicalTrials.gov utilizing the combination of the searched term 'primary sclerosing cholangitis' with other keywords, such as 'clinical trials,' 'antibiotics,' or drug names. Clinical trials at phase II or further were included for consideration.

EXPERT OPINION

Only vancomycin demonstrated promising therapeutic effects in the phase III clinical trial. Other drug candidates showed futility or inconsistent results, and the search for novel PSC treatments is still ongoing.

A multi-omics approach to investigate characteristics of gut microbiota and metabolites in hypertension and diabetic nephropathy SPF rat models

Background

Imbalance in intestinal microbiota caused by microbial species and proportions or metabolites derived from microbes are associated with hypertension, as well as diabetic nephropathy. However, the involvement of the intestinal microbiota and metabolites in hypertension and diabetic nephropathy comorbidities (HDN) remains to be elucidated.

Methods

We investigated the effects of intestinal microbiota on HDN in a rat model and determined the abundance of the intestinal microbiota using 16S rRNA sequencing. Changes in fecal and serum metabolites were analyzed using ultra-high-performance liquid chromatography-mass spectrometry.

Results

The results showed abundance of Proteobacteria and Verrucomicrobia was substantially higher, whereas that of Bacteroidetes was significant lower in the HDN group than in the sham group. Akkermansia, Bacteroides, Blautia, Turicibacter, Lactobacillus, Romboutsia, and Fusicatenibacter were the most abundant, and Prevotella, Lachnospiraceae_NK4A136_group, and Prevotella_9 were the least abundant in the HDN group. Further analysis with bile acid metabolites in serum showed that Blautia was negatively correlated with taurochenodeoxycholic acid, taurocholic acid, positively correlated with cholic acid and glycocholic acid in serum.

Conclusions

These findings suggest that the gut microbiota and metabolites in feces and serum substantially differed between the HDN and sham groups. The F/B ratio was higher in the HDN group than in the sham group. Blautia is potentially associated with HDN that correlated with differentially expressed bile acid metabolites, which might regulate the pathogenesis of HDN via the microorganism-gut-metabolite axis.

Isomers-oriented separation of forty-five plasma bile acids with liquid chromatography-tandem mass spectrometry

Some bile acids (BAs) were considered as biomarkers or have therapeutical effect on metabolic diseases. However, due to the existence of isomers and limitations in sensitivity, simultaneous quantification of multiple BAs remains a challenge. The aim of this study is to establish an accurate and sensitive method for the determination of multiple BAs with similar polarity. A LC-MS/MS analytical method capable of quantifying forty-five BAs simultaneously using nine stable isotope internal standards was developed and fully validated based on key isomers-oriented separation strategy. The method was further applied to analyze plasma samples to describe the dynamic profile of BAs after high glucose intake. The chromatography and mass spectrum conditions were optimized to enable the accurate quantification of forty-five BAs, while ensuring the lower limit of quantification between 0.05-10 ng/mL. The results of system suitability, linearity, dilution integrity, accuracy and precision demonstrated the good quantitative capacity and robustness of the method. A total of thirty-five BAs were quantified in plasma samples from twelve healthy Chinese individuals. The established method featured superior sensitivity and better separation efficiency compared to previous studies. Meanwhile, BAs exhibited correlations with glucose and insulin, suggesting their potential as biomarkers for metabolic disorders.

Unlocking the Therapeutic Potential of Ellagic Acid for Non-Alcoholic Fatty Liver Disease and Non-Alcoholic Steatohepatitis

Obesity is in epidemic proportions in many parts of the world, contributing to increasing rates of non-alcoholic fatty liver disease (NAFLD). NAFLD represents a range of conditions from the initial stage of fatty liver to non-alcoholic steatohepatitis (NASH), which can progress to severe fibrosis, through to hepatocellular carcinoma. There currently exists no treatment for the long-term management of NAFLD/NASH, however, dietary interventions have been investigated for the treatment of NASH, including several polyphenolic compounds. Ellagic acid is one such polyphenolic compound. Nutraceutical food abundant in ellagic acid undergoes initial hydrolysis to free ellagic acid within the stomach and small intestine. The proposed mechanism of action of ellagic acid extends beyond its initial therapeutic potential, as it is further broken down by the gut microbiome into urolithin. Both ellagic acid and urolithin have been found to alleviate oxidative stress, inflammation, and fibrosis, which are associated with NAFLD/NASH. While progress has been made in understanding the pharmacological and biological activity of ellagic acid and its involvement in NAFLD/NASH, it has yet to be fully elucidated. Thus, the aim of this review is to summarise the currently available literature elucidating the therapeutic potential of ellagic acid and its microbial-derived metabolite urolithin in NAFLD/NASH.

Evaluation of the significance of single nucleotide polymorphisms of the ABCB11 gene as biomarkers of hepatological complications in Epstein-Barr virus infection in children

Aim of the study

To evaluate single nucleotide polymorphisms of the adenosine triphosphate (ATP) binding cassette subfamily B member 11 (ABCB11) gene, rs11568364 and rs2287622, as potential predictors of hepatologic complications during Epstein-Barr virus (EBV) infection among children.

Material and methods

The study group consisted of 54 children aged 1 to 18 years hospitalised from 01.12.2018 to 31.12.2020 in the Department of Paediatrics, Infectious Diseases and Hepatology with hepatological complications in the course of serologically and molecularly confirmed EBV infection. Real-time PCR using TaqMan probes was used to determine single-nucleotide variability in the ABCB11 gene.

Results

It was found that the presence of the T allele for the rs2287622 marker increases the probability of hepatitis three times and the possibility of hepatitis with cholestasis almost four times in EBV-infected patients.

Conclusions

The rs2287622 polymorphism of the ABCB11 gene appears to have an impact on the occurrence of hepatological complications in the course of EBV infection in children.

Evaluation of maternal serum vascular endothelial growth factor C and D levels in intrahepatic cholestasis of pregnancy

OBJECTIVE

This study aimed to investigate maternal serum vascular endothelial growth factor (VEGF) C and D levels in patients with intrahepatic cholestasis of pregnancy (ICP).

METHODS

A total of 83 patients, including 41 patients with ICP and 42 healthy pregnant women, were included in the study. We first compared the maternal serum VEGF-C and VEGF-D levels between the ICP and control groups and then examined the correlation between the serum VEGF-C level and the bile acid level in patients with severe ICP.

RESULTS

We observed statistically significantly higher serum VEGF-C levels and lower VEGF-D levels in the ICP group compared with the healthy controls (P < 0.001 and P = 0.015, respectively). According to receiver operating characteristic analysis, the optimal cutoff value for ICP was 147 ng/mL in the determination of the VEGF-C level (specificity and sensitivity: 76%). In patients with severe ICP, the serum VEGF-C statistically significantly correlated with the bile acid level (P = 0.019).

CONCLUSION

This study showed that the maternal serum VEGF-C level was higher and the VEGF-D level was lower in patients with ICP compared with healthy pregnant women. We also found that the VEGF-C level was correlated with the serum bile acid level in patients with severe ICP. Serum VEGF-C level can be used in the diagnosis and follow-up of intrahepatic pregnancy cholestasis.

Preparing and evaluating the anti-microbial effect of Allium jesdianum mouthwash on some of the most common oral microorganisms

Background

Due to the increasing resistance of bacteria to antibiotics and anti-bacterial compounds in plants, Allium jesdianum Boiss plant extract can be used in mouthwash compounds with its anti-microbial activity.

Methods and Materials

The anti-bacterial and anti-fungal activity of A. jesdianum mouthwash was investigated on Streptococcus mutans, Streptococcus sanguis, S. salivarius and Candida albicans, and Candida tropicalis. To analyse the anti-microbial effect of this mouthwash, minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were determined by the broth microdilution method.

Results

The average MIC and MBC of A. jesdianum mouthwash for S. mutans were 1.56 and 3.12 (mg/ml), respectively, for S. salivarius, 0.25 and 0.65 (mg/ml), and for S. sanguis, respectively, 0.25 and 0.65 (mg/ml). The highest MIC and MBC values were for S. mutans, and the MIC and MBC values were equal for S. sanguis and S. salivarius. Average MIC and MBC were determined as 2.41 and 4.16 (mg/ml) for C. albicans and 2.34 and 5.72 (mg/ml) for C. tropicalis, respectively. MIC values of mouthwash were higher for C. albicans and MBC values for C. tropicalis.

Conclusion

Our results showed a promising anti-fungal-anti-bacterial effect of A. jesdianum extract. A. jesdianum extract may be used as an alternative to chemical mouthwashes.

Intrahepatic cholestasis of pregnancy: insights into pathogenesis and advances in omics studies

Intrahepatic cholestasis of pregnancy (ICP) is the most common pregnancy-specific liver disease. It is characterized by pruritus, abnormal liver function and elevated total bile acid (TBA) levels, increasing the risk of maternal and fetal adverse outcomes. Its etiology remains poorly elucidated. Over the years, various omics techniques, including metabolomics, microbiome, genomics, etc., have emerged with the advancement of bioinformatics, providing a new direction for exploring the pathogenesis, diagnosis and treatment of ICP. In this review, we first summarize the role of bile acids and related components in the pathogenesis of ICP and then further illustrate the results of omics studies.

UDCA for Drug-Induced Liver Disease: Clinical and Pathophysiological Basis

Drug-induced liver injury (DILI) is an adverse reaction to medications and other xenobiotics that leads to liver dysfunction. Based on differential clinical patterns of injury, DILI is classified into hepatocellular, cholestatic, and mixed types; although hepatocellular DILI is associated with inflammation, necrosis, and apoptosis, cholestatic DILI is associated with bile plugs and bile duct paucity. Ursodeoxycholic acid (UDCA) has been empirically used as a supportive drug mainly in cholestatic DILI, but both curative and prophylactic beneficial effects have been observed for hepatocellular DILI as well, according to preliminary clinical studies. This could reflect the fact that UDCA has a plethora of beneficial effects potentially useful to treat the wide range of injuries with different etiologies and pathomechanisms occurring in both types of DILI, including anticholestatic, antioxidant, anti-inflammatory, antiapoptotic, antinecrotic, mitoprotective, endoplasmic reticulum stress alleviating, and immunomodulatory properties. In this review, a revision of the literature has been performed to evaluate the efficacy of UDCA across the whole DILI spectrum, and these findings were associated with the multiple mechanisms of UDCA hepatoprotection. This should help better rationalize and systematize the use of this versatile and safe hepatoprotector in each type of DILI scenarios.

Bile acids metabolism involved in the beneficial effects of Danggui Shaoyao San via gut microbiota in the treatment of CCl4 induced hepatic fibrosis

ETHNOPHARMACOLOGICAL RELEVANCE

Danggui Shaoyao San (DSS) is a traditional Chinese medicine (TCM) first recorded in the Synopsis of the Golden Chamber. DSS has proven efficacy in treating hepatic fibrosis (HF). However, the effects and mechanisms of DSS on HF are not clear.

AIM OF THE STUDY

To investigate the effect of DSS on HF via gut microbiota and its metabolites (SCFAs, BAs).

MATERIALS AND METHODS

HF rats were induced with CCl4 and treated with DSS. Firstly, the therapeutic efficacy of DSS in HF rats and the protection of gut barrier were assessed. Then, 16S rRNA gene sequencing and untargeted fecal metabolomics preliminarily explored the mechanism of DSS in treating HF, and identified different microbiota and metabolic pathways. Finally, targeted metabolomics and RT-qPCR were used to further validate the mechanism of DSS for HF based on the metabolism of SCFAs and BAs.

RESULTS

After 8 weeks of administration, DSS significantly reduced the degree of HF. In addition, DSS alleviated inflammation in the ileum and reduced the levels of LPS and D-lactate. Furthermore, DSS altered the structure of gut microbiota, especially Veillonella, Romboutsia, Monoglobus, Parabacteroides, norank_f_Coriobacteriales_Incertae_Sedis. These bacteria have been linked to the production of SCFAs and the metabolism of BAs. Untargeted metabolomics suggested that DSS may play a role via BAs metabolism. Subsequently, targeted metabolomics and RT-qPCR further confirmed the key role of DSS in increasing SCFAs levels and regulating BAs metabolism.

CONCLUSIONS

DSS can alleviate CCl4-induced HF and protect the gut barrier. DSS may exert its beneficial effects on HF by affecting the gut microbiota and its metabolites (SCFAs, BAs).

Clostridium scindens exacerbates experimental necrotizing enterocolitis via upregulation of the apical sodium-dependent bile acid transporter

Necrotizing enterocolitis (NEC) is the most common gastrointestinal emergency in premature infants. Evidence indicates that bile acid homeostasis is disrupted during NEC: ileal bile acid levels are elevated in animals with experimental NEC, as is expression of the apical sodium-dependent bile acid transporter (Asbt). In addition, bile acids, which are synthesized in the liver, are extensively modified by the gut microbiome, including via the conversion of primary bile acids to more cytotoxic secondary forms. We hypothesized that the addition of bile acid-modifying bacteria would increase susceptibility to NEC in a neonatal rat model of the disease. The secondary bile acid-producing species Clostridium scindens exacerbated both incidence and severity of NEC. C. scindens upregulated the bile acid transporter Asbt and increased levels of intraenterocyte bile acids. Treatment with C. scindens also altered bile acid profiles and increased hydrophobicity of the ileal intracellular bile acid pool. The ability of C. scindens to enhance NEC requires bile acids, as pharmacological sequestration of ileal bile acids protects animals from developing disease. These findings indicate that bile acid-modifying bacteria can contribute to NEC pathology and provide additional evidence for the role of bile acids in the pathophysiology of experimental NEC.NEW & NOTEWORTHY Necrotizing enterocolitis (NEC), a life-threatening gastrointestinal emergency in premature infants, is characterized by dysregulation of bile acid homeostasis. We demonstrate that administering the secondary bile acid-producing bacterium Clostridium scindens enhances NEC in a neonatal rat model of the disease. C. scindens-enhanced NEC is dependent on bile acids and driven by upregulation of the ileal bile acid transporter Asbt. This is the first report of bile acid-modifying bacteria exacerbating experimental NEC pathology.

Study on the acute toxicity of sodium taurocholate via zebrafish mortality, behavioral response, and NMR-metabolomics analysis

Sodium taurocholate (NaT) is a hydrophobic bile salt that exhibits varying toxicity and antimicrobial activity. The accumulation of BSs during their entero-hepatic cycle causes cytotoxicity in the liver and intestine and could also alter the intestinal microbiome leading to various diseases. In this research, the acute toxicity of sodium taurocholate in different concentrations (3000 mg/L, 1500 mg/L, 750 mg/L, 375 mg/L, and 0 mg/L) was investigated on four months old zebrafish by immersion in water for 96 h. The results were determined based on the fish mortality, behavioral response, and NMR metabolomics analysis which revealed LC50 of 1760.32 mg/L and 1050.42 mg/L after 72 and 96 h treatment, respectively. However, the non-lethal NaT concentrations of 750 mg/L and 375 mg/L at 96 h exposure significantly (p ≤ 0.05) decreased the total distance traveled and the activity duration, also caused surface respiration on the zebrafish. Orthogonal Projections to Latent Structures Discriminant Analysis (OPLS-DA) revealed that the metabolome of the fish treated with 750 mg/L was discriminated from that of the control by PC1. Major significantly downregulated metabolites by NaT-induction include valine, isoleucine, 2-hydroxyvalerate, glycine, glycerol, choline, glucose, pyruvate, anserine, threonine, carnitine and homoserine. On the contrary, taurine, creatine, lactate, acetate and 3-hydroxybutyrate were upregulated suggesting cellular consumption of lipids, glucose and amino acids for adenosine triphosphate (ATP) generation during immune and inflammatory response. whereby these metabolites were released in the process. In conclusion, the research revealed the toxic effect of NaT and its potential to trigger changes in zebrafish metabolism.