Bile acids induce inflammatory genes in hepatocytes: a novel mechanism of inflammation during obstructive cholestasis. Am J Pathol. 2011;178:175-186. [PMID: 21224055 DOI: 10.1016/j.ajpath.2010.11.026]

A new human autologous hepatocyte/macrophage co-culture system that mimics drug-induced liver injury-like inflammation

The development of in vitro hepatocyte cell culture systems is crucial for investigating drug-induced liver injury (DILI). One prerequisite for monitoring DILI related immunologic reactions is the extension of primary human hepatocyte (PHH) cultures towards the inclusion of macrophages. Therefore, we developed and characterized an autologous co-culture system of PHH and primary human hepatic macrophages (hepM) (CoC1). We compared CoC1 with a co-culture of the same PHH batch + M0 macrophages derived from THP1 cells (CoC2) in order to represent a donor independent macrophage reaction. Then, we treated the mono- and co-cultures with drugs that cause DILI-menadione (MEN, 1 or 10 µM, 3 h), diclofenac (DIC, 0.5 or 5 mM, 6 h), or acetaminophen (APAP, 0.5 or 5 mM, 6 h)-and assessed culture stability, cell activity, macrophage differentiation, cytokine production and cell viability. Without drug treatment, CoC1 was the most stable over a culture time of up to 60 h. Cytokine array analysis revealed a proinflammatory profile of PHH mono-cultures due to isolation stress but showed different influences of hepM and M0 on the cytokine profile in the co-cultures. MEN, DIC and APAP treatment led to donor-dependent signs of cell stress and toxicity. HepM can either promote or reduce the DILI effects donor dependently in CoC1. CoC2 are slightly less sensitive than CoC1 in representing DILI. In summary, we present a new autologous co-culture system that can mimic DILI in a donor-dependent manner. This cellular system could be useful for new drug testing strategies and reducing animal testing.

Inhibition of RAC1 activator DOCK2 ameliorates cholestatic liver injury via regulating macrophage polarisation and hepatic stellate cell activation

BACKGROUND

The Rho GTPase Rac family small GTPase 1 (RAC1) is considered a promising fibrotic therapeutic target, but the role of its activator, dedicator of cytokinesis 2 (DOCK2), in liver fibrosis is largely unknown. This study aimed to investigate the expression and role of DOCK2 in cholestasis-induced liver fibrosis and to further explore the potential mechanisms.

RESULTS

Cholestasis was induced in male C57BL/6 mice by bile duct ligation (BDL). DOCK2 knockdown was achieved by tail vein injection of adenovirus containing DOCK2-targeting shRNA. The effect of DOCK2 knockdown on cholestatic liver injury was evaluated at different time points after BDL. Hepatic DOCK2 expression gradually increased after BDL. Knockdown of DOCK2 reduced the necrotic area in BDL liver and downregulated serum levels of liver injury indicators. At 3d post-BDL (acute phase), DOCK2 knockdown alleviated M1 macrophage inflammation in the liver, as evidenced by reduced infiltrating iNOS + macrophages and inflammatory cytokines and mitigated NLRP3 inflammasome activation. At 14d post-BDL (chronic phase), DOCK2 knockdown suppressed hepatic stellate cell (HSC) activation and liver fibrosis as indicated by decreased α-SMA + HSCs and extracellular matrix deposition. In vitro experiments further demonstrated that DOCK2 knockdown suppressed M1 macrophage polarisation and HSC to myofibroblast transition, accompanied by inhibition of RAC1 activation.

CONCLUSIONS

In summary, this study demonstrates for the first time that the RAC1 activator DOCK2 regulates M1 macrophage polarisation and hepatic stellate cell activation to promote cholestasis-induced liver inflammation and fibrosis, suggesting that DOCK2 may be a potential therapeutic target in cholestatic liver injury.

Sequential versus continuous feeding and its effect on the gut microbiota in critically ill patients: A randomized controlled trial

BACKGROUND

Gut microbiota disturbance may worsen critical illnesses and is responsible for the progression of multiple organ dysfunction syndrome. In our previous study, there was a trend towards a higher α-diversity of the gut microbiota in sequential feeding (SF) than in continuous feeding (CF) for critically ill patients. We designed this non-blinded, randomized controlled study to confirm these results.

METHODS

All the enrolled patients received continuous feeding in the beginning. After achieving ≥80 % of the nutrition target calories (25-30 kcal/kg/d), the patients were randomized into the SF group or the CF group. In the SF group, continuous feeding was changed into intermittent feeding. The total daily dosage of enteral nutrition was equally distributed during three periods at 7-9:00, 11-13:00 and 17-19:00. After 7 days of randomization, fresh stool and serum were collected for 16S rRNA gene sequencing and untargeted metabolomics analysis respectively. Meanwhile, routine blood test indicators and metabolic indicators were recorded.

RESULTS

Finally, data from 65 patients in the SF group and 69 patients in the CF group were used for intention-to-treat analysis. There was no difference in the Shannon index between the SF group and CF group [2.5 (1.7-3.4) vs. 2.6 (1.5-3.5), P = 0.934]. However, at the genus level, the abundances of Erysipelotrichaceae_UCG-003 and Howardella increased in the SF group. Some metabolic indicators (the albumin level, total cholesterol level and total bile acid level) and the increases in lymphocyte counts in the SF group were different from those in the CF group (P < 0.05). In untargeted metabolomic analysis, 58 differentially abundant metabolites between the two groups were found. The pathway with the highest enrichment factors was primary bile acid biosynthesis according to the Kyoto Encyclopedia of Genes and Genomes Database classification. Regarding adverse events, the gut tolerance, average glucose and incidence of hyperglycemia and hypoglycemia were similar between the SF group and CF group. The mortality rate in the SF group was lower than that in the CF group, but there was no statistical difference (9.2 % vs. 13.0 %, P = 0.484).

CONCLUSION

SF did not increase the diversity of gut microbiota in critically ill patients. However, it did alter the abundances of some gut microbes and affect some metabolites. Its clinical significance requires further exploration. In addition, the gut tolerance and safety of SF were similar to that of CF.

TRIAL REGISTRATION

www.

CLINICALTRIALS

gov, registration number NCT04443335. Registered 21 June, 2020.

Multiomics analysis elucidated the role of inflammatory response and bile acid metabolism disturbance in electric shock-induced liver injury in mice

PURPOSE

Organ damage caused by electric shock has attracted great attention. Some animal investigations and clinical cases have suggested that electric shock can induce liver injury. This study aimed to investigate the potential mechanism of liver injury induced by electric shock.

METHODS

Healthy male C57BL/6J mice aged 6-8 weeks were romandly divided into two groups: control group and electric shock group. Mice in the electric shock group were shocked on the top of the skull with an electric baton (20 kV) for 5 sec, while mice in the control group were exposed to only the acoustic and light stimulation produced by the electric baton. The effect of electric shock on liver function was evaluated by histological and biochemical analysis, and a metabolomics and transcriptomics study was performed to investigate how electric shock might induce liver damage. All data of this study were analyzed using a two-tailed unpaired Student's t-test in SPSS 22.0 Statistical Package.

RESULTS

The electric shock group had significantly higher serum aspartate aminotransferase and alanine aminotransferase levels than the control group (p < 0.001), and the shock notably caused cytoplasmic swelling and vacuolization, mild inflammatory cell (mainly macrophages and monocytes) infiltration and acute focal necrosis in hepatocytes (p < 0.001). A total of 47 differential metabolites and 249 differentially expressed genes (DEGs) were detected using metabolomic and transcriptomic analyses. These differential metabolites were significantly enriched in primary bile acid biosynthesis (p < 0.05). Gene ontology functional analysis of the DEGs revealed that electric shock disturbed a key biological process involved in the inflammatory response in the mouse liver, and a significant number of DEGs were enriched in Kyoto Encyclopedia of Genes and Genomes-identified pathways related to inflammation, such as the interleukin-17, tumor necrosis factor and mitogen-activated protein kinase signalling pathway. Transcriptomic and metabolomic analyses revealed that bile acid metabolism disturbance including up-regulation of the taurochenodesoxycholic acid, chenodeoxycholic acid and taurocholic acid, and down-regulation of chenodeoxycholic acid clycine conjugate may contribute to the electric shock-induced inflammatory response.

CONCLUSION

Electric shock can induce liver inflammatory injury through the interleukin-17, tumor necrosis factor, and mitogen-activated protein kinase signaling pathway, and the bile acid metabolism disturbance including up-regulation of the taurochenodesoxycholic acid, chenodeoxycholic acid and taurocholic acid, and down-regulation of chenodeoxycholic acid clycine conjugate may contribute to inflammatory liver injury following electric shock.

Porcine bile acids improve performance by altering hepatic lipid metabolism and amino acid metabolism with different protein level diets in late laying hens

As the extension of the egg-laying cycle, heightened energy and lipid metabolism cause excessive lipid accumulation, resulting in rapid decline in laying performance during the late laying period. Bile acids (BAs), synthesized from cholesterol in the liver, are potent metabolic and immune signaling molecules involved in lipid metabolism and the regulation of energy homeostasis. However, under different dietary protein levels, the role of BAs on hepatic lipid metabolism of laying hens at the late phase remains unclear. This experiment aimed to evaluate the effects of porcine BAs supplementation on performance, lipid metabolism, antioxidant status and amino acid metabolism in late-phase laying hens fed diets with different protein level. A total of 192 Hy-Line Brown laying hens (62 weeks of age) were randomly assigned to one of four treatment groups, in a 2 × 2 factorial design, with 8 replicates per treatment. The hens were fed diets with either normal protein (16.42 %) or low-protein (15.35 %) levels, with or without BAs supplementation (120 mg/kg for the first 56 days, followed by 200 mg/kg for the next 42 days). The results demonstrated that dietary BAs supplementation significantly enhanced egg production and feed intake (P < 0.05) although it has no notable effect on egg quality. Bile acids supplementation effectively reduced liver total cholesterol (TC), triglyceride (TG), as well as malondialdehyde (MDA) levels, while also ameliorating lipid deposition through the regulation of expression of lipid metabolism-related genes in late laying hens (P < 0.05). Additionally, the low-protein diets downregulated amino acid catabolism, thereby reducing serum uric acid content and enhancing protein utilization. Further analysis revealed that BAs also positively influenced trypsin activity and increased the expression of amino acid transporters, thereby improving amino acid availability (P < 0.05). In conclusion, this study demonstrated that dietary BAs supplementation could enhance the laying performance in late laying hens, primarily by improving hepatic lipid metabolism, antioxidant capacity, and amino acid availability.

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.

Interleukin 1 β suppresses bile acid-induced BSEP expression via a CXCR2-dependent feedback mechanism

Inflammation-induced cholestasis is a common problem in septic patients and results from cytokine-mediated inhibition of bile acid export including impaired expression of the bile salt export pump (BSEP) with a consecutive increase in intracellular bile acids mediating cell damage. The present study focuses on the mechanisms by which interleukin 1 β (IL-1β), as a critical mediator of sepsis-induced cholestasis, controls the expression of BSEP in hepatocytes. Notably, the treatment of hepatocytes with IL-1β leads to the upregulation of a broad chemokine pattern. Thereby, the IL-1β -induced expression of in particular the CXCR2 ligands CXCL1 and 2 is further enhanced by bile acids, whereas the FXR-mediated upregulation of BSEP induced by bile acids is inhibited by IL-1β. In this context, it is interesting to note that inhibitor studies indicate that IL-1β mediates its inhibitory effects on bile acid-induced expression of BSEP indirectly via CXCR2 ligands. Consistently, inhibition of CXCR2 with the inhibitor SB225002 significantly attenuated of the inhibitory effect of IL-1β on BSEP expression. These data suggest that part of the cholestasis-inducing effect of IL-1β is mediated via a CXCR2-dependent feedback mechanism.

Analysis of changes in platelet parameters and inflammatory markers in intrahepatic cholestasis of pregnancy before disease development

BACKGROUND

Intrahepatic cholestasis of pregnancy (ICP) is the most common liver condition during pregnancy, associated with adverse outcomes for both mother and fetus. While inflammatory markers are important predictors in oncology and cardiovascular disease, their role in ICP remains unclear. This study investigates changes in platelet parameters and blood-derived inflammatory markers around the onset of ICP and evaluates their potential as independent risk factors.

METHODS

This retrospective study analyzed inflammatory markers, including the Neutrophil-to-Lymphocyte Ratio (NLR), Derived NLR (dNLR), Monocyte-to-Lymphocyte Ratio (MLR), Neutrophil-Monocyte-to-Lymphocyte Ratio (NMLR), Systemic Inflammation Response Index (SIRI), and Systemic Immune-Inflammation Index (SII) along with variations in platelet parameters in 49 ICP patients and 250 healthy controls during late pregnancy, specifically at disease onset. Additionally, changes in these parameters were assessed among the same 49 ICP patients compared to 1439 healthy controls during early pregnancy.

RESULTS

During an episode of ICP, individuals exhibited increased platelet parameters, including PCT, P-LCR, PDW and MPV, compared to those with uncomplicated pregnancies. The levels of WBC, NEUT, NLR, dNLR, NMLR, SIRI, and SII were also elevated in the ICP group relative to the control group. Prior to disease onset, platelet parameters such as PCT and PDW, along with inflammatory markers including NEUT, NLR, NMLR, SIRI, and SII, were significantly higher in ICP patients. Additionally, a notable increase in HGB, HCT, MCV, MCH, and RDW-CV was observed in the ICP group, while MCHC was decreased. Logistic regression analysis identified MCV, PDW and SII as risk factors for developing ICP.

CONCLUSIONS

PCT, PDW, NEUT, NLR, NMLR, SIRI, and SII levels were significantly elevated both before and during the progression of ICP. Notably, MCV, PDW, and SII were identified as independent risk factors, representing new predictive indicators for the development of ICP.

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.

Jag1 insufficiency alters liver fibrosis via T cell and hepatocyte differentiation defects

Fibrosis contributes to tissue repair, but excessive fibrosis disrupts organ function. Alagille syndrome (ALGS, caused by mutations in JAGGED1) results in liver disease and characteristic fibrosis. Here, we show that Jag1Ndr/Ndr mice, a model for ALGS, recapitulate ALGS-like fibrosis. Single-cell RNA-seq and multi-color flow cytometry of the liver revealed immature hepatocytes and paradoxically low intrahepatic T cell infiltration despite cholestasis in Jag1Ndr/Ndr mice. Thymic and splenic regulatory T cells (Tregs) were enriched and Jag1Ndr/Ndr lymphocyte immune and fibrotic capacity was tested with adoptive transfer into Rag1-/- mice, challenged with dextran sulfate sodium (DSS) or bile duct ligation (BDL). Transplanted Jag1Ndr/Ndr lymphocytes were less inflammatory with fewer activated T cells than Jag1+/+ lymphocytes in response to DSS. Cholestasis induced by BDL in Rag1-/- mice with Jag1Ndr/Ndr lymphocytes resulted in periportal Treg accumulation and three-fold less periportal fibrosis than in Rag1-/- mice with Jag1+/+ lymphocytes. Finally, the Jag1Ndr/Ndr hepatocyte expression profile and Treg overrepresentation were corroborated in patients' liver samples. Jag1-dependent hepatic and immune defects thus interact to determine the fibrotic process in ALGS.

Free fatty acids induce bile acids overproduction and oxidative damage of bovine hepatocytes via inhibiting FXR/SHP signaling

Hepatic oxidative injury induced by free fatty acids (FFA) and metabolic disorders of bile acids (BA) increase the risk of metabolic diseases in dairy cows during perinatal period. However, the effects of FFA on BA metabolism remained poorly understood. In present study, high concentrations of FFA caused cell impairment, oxidative stress and BA overproduction. FFA treatment increased the expression of BA synthesis-related genes [cholesterol 7a-hydroxylase (CYP7A1), hydroxy-delta-5-steroid dehydrogenase, 3 beta- and steroid delta-isomerase 7, sterol 12α-hydroxylase, sterol 27-hydroxylase and oxysterol 7α-hydroxylase], whereas reduced BA exportation gene (ATP binding cassette subfamily C member 1) and inhibited farnesoid X receptor/small heterodimer partner (FXR/SHP) pathway in bovine hepatocytes. Knockdown of nuclear receptor subfamily 1 group H member 4 (NR1H4) worsened FFA-caused oxidative damage and BA production, whereas overexpression NR1H4 ameliorated FFA-induced BA production and cell oxidative damage. Besides, reducing BA synthesis through knockdown of CYP7A1 can alleviate oxidative stress and hepatocytes impairment caused by FFA. In summary, these data demonstrated that regulation of FXR/SHP-mediated BA metabolism may be a promising target in improving hepatic oxidative injury of dairy cows during high levels of FFA challenges.

Taurocholic acid represents an earlier and more sensitive biomarker and promotes cholestatic hepatotoxicity in ANIT-treated rats

Bile acid homeostasis is crucial for the normal physiological functioning of the liver. Disruptions in bile acid profiles are closely linked to the occurrence of cholestatic liver injury. As part of our diagnostic and therapeutic approach, we aimed to investigate the disturbance in bile acid profiles during cholestasis and its correlation with cholestatic liver injury. Before the occurrence of liver injury, alterations in bile acid profiles were detected in both plasma and liver between 8 and 16 h, persisting up to 96 h. TCA, TCDCA, and TUDCA in the plasma, as well as TCA, TUDCA, TCDCA, TDCA, TLCA, and THDCA in the liver, emerged as early sensitive and potential markers for diagnosing ANIT-induced cholestasis at 8-16 h. The distinguishing features of ANIT-induced liver injury were as follows: T-BAs exceeding G-BAs and serum biochemical indicators surpassing free bile acids. Notably, plasma T-BAs, particularly TCA, exhibited higher sensitivity to cholestatic hepatotoxicity compared with serum enzyme activity and liver histopathology. Further investigation revealed that TCA exacerbated ANIT-induced liver injury by elevating liver function enzyme activity, inflammation, and bile duct proliferation and promoting the migration of bile duct epithelial cell. Nevertheless, no morphological changes or alterations in transaminase activity indicative of liver damage were observed in the rats treated with TCA alone. Additionally, there were no changes in bile acid profiles or inflammatory responses under physiological conditions with maintained bile acid homeostasis. In summary, our findings suggest that taurine-conjugated bile acids in both plasma and liver, particularly TCA, can serve as early and sensitive markers for predicting intrahepatic cholestatic drugs and can act as potent exacerbators of cholestatic liver injury progression. However, exogenous TCA does not induce liver injury under physiological conditions where bile acid homeostasis is maintained.

The impact of artificial liver support system on intestinal microbiota and serum bile acid profiles in patients with acute-on-chronic liver failure: a prospective cohort study

BACKGROUND

Acute-on-chronic liver failure (ACLF) patients exhibit an imbalance in intestinal microbiota, and bile acids (BAs) can affect the composition of intestinal microbiota. Although Artificial liver support system (ALSS) is a treatment for ACLF, the impact of ALSS on intestinal microbiota and serum BA profiles of ACLF patients remains unclear.

METHODS

A prospective study was conducted, which included 51 patients diagnosed with ACLF. These patients were stratified into two groups based on the utilization of an ALSS during their treatment period: a standard medical treatment group (SMT group), comprising 19 patients, and an ALSS combined with SMT group (ALSS group), comprising 32 patients. Blood and stool samples were collected from the patients on the day of admission and 14 days after treatment. Additionally, eight healthy controls were recruited, and their stool samples were also collected. The intestinal microbiota was sequenced using the 16S rRNA sequencing technique, while the serum BA profiles were determined using ultra-performance liquid chromatography/mass spectrometry.

RESULTS

ACLF patients exhibited imbalances in intestinal microbiota and abnormalities in BA profiles. Compared to SMT alone, the combined ALSS and SMT was more effective in regulating intestinal microbiota imbalance and increasing the concentrations of ursodeoxycholic acid and glycoursodeoxycholic acid. Correlation analysis revealed a significant correlation between intestinal microbiota and Bas. Furthermore, the preliminary correlation heatmap indicated that the Faecalibaculum, Gemmiger, and taurochenodeoxycholic acid were associated with clinical improvement.

CONCLUSIONS

Our study identified the compositional characteristics of the intestinal microbiota and serum BA in ACLF patients, emphasizing the impact of ALSS on both intestinal microbiota and serum BA profiles.

Mitochondria at the Crossroads of Cholestatic Liver Injury: Targeting Novel Therapeutic Avenues

Bile acids are byproducts of cholesterol metabolism in the liver and constitute the primary components of bile. Disruption of bile flow leads to cholestasis, characterized by the accumulation of hydrophobic bile acids in the liver and bloodstream. Such accumulation can exacerbate liver impairment. This review discussed recent developments in understanding how bile acids contribute to liver damage, including disturbances in mitochondrial function, endoplasmic reticulum stress, inflammation, and autophagy dysfunction. Mitochondria play a pivotal role in cholestatic liver injury by influencing hepatocyte apoptosis and inflammation. Recent findings linking bile acids to liver damage highlight new potential treatment targets for cholestatic liver injury.

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.

Targeting bacterial metabolites in tumor for cancer therapy: An alternative approach for targeting tumor-associated bacteria

Emerging evidence reveal that tumor-associated bacteria (TAB) can facilitate the initiation and progression of multiple types of cancer. Recent work has emphasized the significant role of intestinal microbiota, particularly bacteria, plays in affecting responses to chemo- and immuno-therapies. Hence, it seems feasible to improve cancer treatment outcomes by targeting intestinal bacteria. While considering variable richness of the intestinal microbiota and diverse components among individuals, direct manipulating the gut microbiota is complicated in clinic. Tumor initiation and progression requires the gut microbiota-derived metabolites to contact and reprogram neoplastic cells. Hence, directly targeting tumor-associated bacteria metabolites may have the potential to provide alternative and innovative strategies to bypass the gut microbiota for cancer therapy. As such, there are great opportunities to explore holistic approaches that incorporates TAB-derived metabolites and related metabolic signals modulation for cancer therapy. In this review, we will focus on key opportunistic areas by targeting TAB-derived metabolites and related metabolic signals, but not bacteria itself, for cancer treatment, and elucidate future challenges that need to be addressed in this emerging field.

The gut microbiota-bile acid axis in cholestatic liver disease

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

Hepatic macrophage niche: a bridge between HBV-mediated metabolic changes with intrahepatic inflammation

Hepatitis B Virus (HBV) is a stealthy and insidious pathogen capable of inducing chronic necro-inflammatory liver disease and hepatocellular carcinoma (HCC), resulting in over one million deaths worldwide per year. The traditional understanding of Chronic Hepatitis B (CHB) progression has focused on the complex interplay among ongoing virus replication, aberrant immune responses, and liver pathogenesis. However, the dynamic progression and crucial factors involved in the transition from HBV infection to immune activation and intrahepatic inflammation remain elusive. Recent insights have illuminated HBV's exploitation of the sodium taurocholate co-transporting polypeptide (NTCP) and manipulation of the cholesterol transport system shared between macrophages and hepatocytes for viral entry. These discoveries deepen our understanding of HBV as a virus that hijacks hepatocyte metabolism. Moreover, hepatic niche macrophages exhibit significant phenotypic and functional diversity, zonal characteristics, and play essential roles, either in maintaining liver homeostasis or contributing to the pathogenesis of chronic liver diseases. Therefore, we underscore recent revelations concerning the importance of hepatic niche macrophages in the context of viral hepatitis. This review particularly emphasizes the significant role of HBV-induced metabolic changes in hepatic macrophages as a key factor in the transition from viral infection to immune activation, ultimately culminating in liver inflammation. These metabolic alterations in hepatic macrophages offer promising targets for therapeutic interventions and serve as valuable early warning indicators, shedding light on the disease progression.

Advances in the mechanism of emodin-induced hepatotoxicity

Emodin is a naturally occurring anthraquinone derivative and serves as an active component in various traditional Chinese herbal medicines. It is widely known for its broad pharmacological effects, including anti-inflammatory, antioxidant, and anticancer properties. However, high doses and long-term use of emodin can also lead to liver toxicity. Nevertheless, the mechanism of emodin-induced liver toxicity remains unclear at present. This article aims to summarize the toxicological research progress on emodin, with a particular focus on elucidating the mechanisms underlying emodin-induced hepatocyte injury. By providing essential information, the study intends to facilitate further research and safe usage of emodin for researchers and clinical practitioners.

Association of cord plasma metabolites with birth weight: results from metabolomic and lipidomic studies of discovery and validation cohorts

OBJECTIVE

Birth weight is a good predictor of fetal intrauterine growth and long-term health, and several studies have evaluated the relationship between metabolites and birth weight. The aim of this study was to investigate the association of cord blood metabolomics and lipidomics with birth weight, using a two-stage discovery and validation approach.

METHODS

Firstly, a pseudotargeted metabolomics approach was applied to detect metabolites in 504 cord blood samples in the discovery set enrolled from the Wuhan Healthy Baby Cohort, China. Metabolome-wide association scan analysis and pathway enrichment were applied to identify metabolites and metabolic pathways that were significantly associated with birth weight adjusted for gestational age Z-score (BW Z-score). Logistic regression models were used to analyze the association of metabolites in the most significantly associated pathways with small-for-gestational age (SGA) at delivery and low birth weight (LBW). Subsequently, 350 cord blood samples in a validation cohort were subjected to targeted analysis to validate the metabolites identified by screening in the discovery cohort.

RESULTS

In the discovery set, of 2566 metabolites detected, 2418 metabolites were retained for subsequent analysis after data preprocessing. Of these, 513 metabolites were significantly associated with BW Z-score (P-value adjusted for false discovery rate (PFDR) < 0.05), of which 298 Kyoto Encyclopedia of Genes and Genomes (KEGG)-annotated metabolites were included in the pathway analysis. The primary bile acid biosynthesis pathway was the most relevant metabolic pathway associated with BW Z-score. Elevated cord plasma primary bile acids were associated with lower BW Z-score and higher risk of SGA or LBW in the discovery and validation cohorts. In the validation set, a 2-fold increase in taurochenodeoxycholic acid (TCDCA) and in taurocholic acid (TCA) was associated with a decrease in BW Z-score (estimated β coefficient, -0.10 (95% CI, -0.20 to 0.00) and -0.18 (95% CI, -0.31 to -0.04), respectively), after adjusting for covariates. In addition, a 2-fold increase in cord plasma TCDCA and of cord plasma TCA was associated with an increased risk of SGA (adjusted odds ratio (OR), 1.52 (95% CI, 1.00-2.30) and 1.77 (95% CI, 1.05-2.98), respectively). The adjusted OR for LBW, for a 2-fold increase in TCDCA and TCA concentration, were 2.39 (95% CI, 1.00-5.71) and 3.21 (95% CI, 0.96-10.74), respectively.

CONCLUSIONS

These results indicate a significant association of elevated primary bile acids, particularly TCDCA and TCA, in cord blood with lower BW Z-score, as well as increased risk of SGA and LBW. Abnormalities of primary bile acid metabolism may play an important role in restricted fetal development. © 2024 International Society of Ultrasound in Obstetrics and Gynecology.

Single-cell transcriptomics unveiled that early life BDE-99 exposure reprogrammed the gut-liver axis to promote a proinflammatory metabolic signature in male mice at late adulthood

Polybrominated diphenyl ethers (PBDEs) are legacy flame retardants that bioaccumulate in the environment. The gut microbiome is an important regulator of liver functions including xenobiotic biotransformation and immune regulation. We recently showed that neonatal exposure to polybrominated diphenyl ether-99 (BDE-99), a human breast milk-enriched PBDE congener, up-regulated proinflammation-related and down-regulated drug metabolism-related genes predominantly in males in young adulthood. However, the persistence of this dysregulation into late adulthood, differential impact among hepatic cell types, and the involvement of the gut microbiome from neonatal BDE-99 exposure remain unknown. To address these knowledge gaps, male C57BL/6 mouse pups were orally exposed to corn oil (10 ml/kg) or BDE-99 (57 mg/kg) once daily from postnatal days 2-4. At 15 months of age, neonatal BDE-99 exposure down-regulated xenobiotic and lipid-metabolizing enzymes and up-regulated genes involved in microbial influx in hepatocytes. Neonatal BDE-99 exposure also increased the hepatic proportion of neutrophils and led to a predicted increase of macrophage migration inhibitory factor signaling. This was associated with decreased intestinal tight junction protein (Tjp) transcripts, altered gut environment, and dysregulation of inflammation-related metabolites. ScRNA-seq using germ-free (GF) mice demonstrated the necessity of a normal gut microbiome in maintaining hepatic immune tolerance. Microbiota transplant to GF mice using large intestinal microbiome from adults neonatally exposed to BDE-99 down-regulated Tjp transcripts and up-regulated several cytokines in large intestine. In conclusion, neonatal BDE-99 exposure reprogrammed cell type-specific gene expression and cell-cell communication in liver towards proinflammation, and this may be partly due to the dysregulated gut environment.

Impact of High-Fat Diet and Exercise on Bone and Bile Acid Metabolism in Rats

Bile acids help facilitate intestinal lipid absorption and have endocrine activity in glucose, lipid and bone metabolism. Obesity and exercise influence bile acid metabolism and have opposite effects in bone. This study investigates if regular exercise helps mitigate the adverse effects of obesity on bone, potentially by reversing alterations in bile acid metabolism. Four-month-old female Sprague Dawley rats either received a high-fat diet (HFD) or a chow-based standard diet (lean controls). During the 10-month study period, half of the animals performed 30 min of running at moderate speed on five consecutive days followed by two days of rest. The other half was kept inactive (inactive controls). At the study's end, bone quality was assessed by microcomputed tomography and biomechanical testing. Bile acids were measured in serum and stool. HFD feeding was related to reduced trabecular (-33%, p = 1.14 × 10-7) and cortical (-21%, p = 2.9 × 10-8) bone mass and lowered femoral stiffness (12-41%, p = 0.005). Furthermore, the HFD decreased total bile acids in serum (-37%, p = 1.0 × 10-6) but increased bile acids in stool (+2-fold, p = 7.3 × 10-9). These quantitative effects were accompanied by changes in the relative abundance of individual bile acids. The concentration of serum bile acids correlated positively with all cortical bone parameters (r = 0.593-0.708), whilst stool levels showed inverse correlations at the cortical (r = -0.651--0.805) and trabecular level (r = -0.656--0.750). Exercise improved some trabecular and cortical bone quality parameters (+11-31%, p = 0.043 to 0.001) in lean controls but failed to revert the bone loss related to the HFD. Similarly, changes in bile acid metabolism were not mitigated by exercise. Prolonged HFD consumption induced quantitative and qualitative alterations in bile acid metabolism, accompanied by bone loss. Tight correlations between bile acids and structural indices of bone quality support further functional analyses on the potential role of bile acids in bone metabolism. Regular moderate exercise improved trabecular and cortical bone quality in lean controls but failed in mitigating the effects related to the HFD in bone and bile acid metabolism.

Proteomic Biomarkers of Intrahepatic Cholestasis of Pregnancy

Intrahepatic cholestasis of pregnancy (ICP) is a pregnancy-specific liver disease, which can lead to adverse fetal outcomes, including preterm labor and intrauterine death. The pathogenesis of ICP is still unclear. We hypothesized that pathological index leads to abnormal placenta changes in ICP. Investigation of these differences in protein expression in parallel profiling is essential to understand the comprehensive pathophysiological mechanism underlying ICP. The present study screened differentially expressed proteins (DEPs) as novel diagnostic markers for ICP. Proteomic profiles of placental tissues from 32 ICP patients and 24 healthy volunteers (controls) were analyzed. Our founding was valid by following western blotting and immunohistochemistry staining, respectively. The association of the key protein expression with clinicopathological features of ICP was further analyzed. A total of 178 DEPs were identified between the ICP and control groups. Functional enrichment analysis showed these proteins were significantly enriched in the PPAR singling pathway by KEGG and PPARα/RXRα activation by IPA. Apolipoprotein A2 (APOA2) was the only upregulated protein, which uniquely identified in ICP groups and related to both pathways. Validation of western blotting and immunohistochemical staining analysis showed significantly higher APOA2 expression in the ICP group than in the control group. Furthermore, the expression of APOA2 is associated with clinicopathological features in ICP groups. Receiver operating characteristic (ROC) curve analyses showed that the AUC of APOA2 was 0.8984 (95% confidence interval (CI): 0.772-1.000). This study has identified up-regulated APOA2 associated with PPAR singling pathway and PPARα/RXRα activation in ICP. Thus, APOA2 may be involved in ICP pathogenesis, serving as a novel biomarker for its diagnosis.

Regulatory effect of Yinchenhao decoction on bile acid metabolism to improve the inflammatory microenvironment of hepatocellular carcinoma in mice

Hepatocellular carcinoma (HCC) is a malignant tumor with extremely high mortality. The tumor microenvironment is the "soil" of its occurrence and development, and the inflammatory microenvironment is an important part of the "soil". Bile acid is closely related to the occurrence of HCC. Bile acid metabolism disorder is not only directly involved in the occurrence and development of HCC but also affects the inflammatory microenvironment of HCC. Yinchenhao decoction, a traditional Chinese medicine formula, can regulate bile acid metabolism and may affect the inflammatory microenvironment of HCC. To determine the effect of Yinchenhao decoction on bile acid metabolism in mice with HCC and to explore the possible mechanism by which Yinchenhao decoction improves the inflammatory microenvironment of HCC by regulating bile acid metabolism, we established mice model of orthotopic transplantation of hepatocellular carcinoma. These mice were treated with three doses of Yinchenhao decoction, then liver samples were collected and tested. Yinchenhao decoction can regulate the disorder of bile acid metabolism in liver cancer mice. Besides, it can improve inflammatory reactions, reduce hepatocyte degeneration and necrosis, and even reduce liver weight and the liver index. Taurochenodeoxycholic acid, hyodeoxycholic acid, and taurohyodeoxycholic acid are important molecules in the regulation of the liver inflammatory microenvironment, laying a foundation for the regulation of the liver tumor inflammatory microenvironment based on bile acids. Yinchenhao decoction may improve the inflammatory microenvironment of mice with HCC by ameliorating hepatic bile acid metabolism.

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.

Bile acid and nonalcoholic steatohepatitis: Molecular insights and therapeutic targets

BACKGROUND

Nonalcoholic steatohepatitis (NASH) has been the second most common cause of liver transplantation in the United States. To date, NASH pathogenesis has not been fully elucidated but is multifactorial, involving insulin resistance, obesity, metabolic disorders, diet, dysbiosis, and gene polymorphism. An effective and approved therapy for NASH has also not been established. Bile acid is long known to have physiological detergent function in emulsifying and absorbing lipids and lipid-soluble molecules within the intestinal lumen. With more and more in-depth understandings of bile acid, it has been deemed to be a pivotal signaling molecule, which is capable of regulating lipid and glucose metabolism, liver inflammation, and fibrosis. In recent years, a plethora of studies have delineated that disrupted bile acid homeostasis is intimately correlated with NASH disease severity.

AIMS

The review aims to clarify the role of bile acid in hepatic lipid and glucose metabolism, liver inflammation, as well as liver fibrosis, and discusses the safety and efficacy of some pharmacological agents targeting bile acid and its associated pathways for NASH.

KEY SCIENTIFIC CONCEPTS OF REVIEW

Bile acid has a salutary effect on hepatic metabolic disorders, which can ameliorate liver fat accumulation and insulin resistance mainly through activating Takeda G-protein coupled receptor 5 and farnesoid X receptor. Moreover, bile acid also exerts anti-inflammation and anti-fibrosis properties. Furthermore, bile acid has great potential in nonalcoholic liver disease stratification and treatment of NASH.

Systemic Inflammation Response Index as a diagnostic and prognostic predictor of intrahepatic cholestasis of pregnancy: A case-control study from a tertiary center

OBJECTIVE

To investigate the diagnostic and prognostic value of the Systemic Inflammation Response Index (SIRI) in intrahepatic cholestasis of pregnancy (ICP).

METHODS

The present case-control study comprised 386 participants, including 192 women with ICP and 194 gestational age-matched pregnant women. Increased fasting biliary acid (FBA) levels (≥10 μmol/L) were accepted as ICP criteria. SIRI values were calculated for the first trimester (SIRI 1), time of diagnosis (SIRI 2), and time of delivery (SIRI 3). The ICP and control groups were compared based on SIRI values, and on obstetrical and neonatal outcomes. The ICP subgroups based on FBA levels (severe ICP [FBA ≥40 μmol/L] and mild ICP [FBA <40 μmol/L]) were also compared for SIRI and pregnancy outcomes.

RESULTS

Adverse outcomes were significantly higher in the ICP group (P < 0.001). SIRI 2 and SIRI 3 showed negative significant differences between the ICP and control groups, with P values of 0.001 and 0.009, respectively. A significant difference in ICP severity subgroups (P = 0.046) was observed for SIRI 3. In receiver operating characteristics curve analyses, optimal cut-off values for the prediction of ICP were found to be 2.01 and 2.08 for SIRI 2 and SIRI 3, respectively. A cut-off value 1.74 was determined to predict the disease severity for SIRI 3.

CONCLUSION

SIRI has clinical significance in accordance with the inflammatory etiology of ICP. SIRI might be used with other clinical and laboratory findings for ICP diagnosis and prediction.

Uncovering a Novel Functional Interaction Between Adult Hepatic Progenitor Cells, Inflammation and EGFR Signaling During Bile Acids-Induced Injury

Chronic cholestatic damage is associated to both accumulation of cytotoxic levels of bile acids and expansion of adult hepatic progenitor cells (HPC) as part of the ductular reaction contributing to the regenerative response. Here, we report a bile acid-specific cytotoxic response in mouse HPC, which is partially impaired by EGF signaling. Additionally, we show that EGF synergizes with bile acids to trigger inflammatory signaling and NLRP3 inflammasome activation in HPC. Aiming at understanding the impact of this HPC specific response on the liver microenvironment we run a proteomic analysis of HPC secretome. Data show an enrichment in immune and TGF-β regulators, ECM components and remodeling proteins in HPC secretome. Consistently, HPC-derived conditioned medium promotes hepatic stellate cell (HSC) activation and macrophage M1-like polarization. Strikingly, EGF and bile acids co-treatment leads to profound changes in the secretome composition, illustrated by an abolishment of HSC activating effect and by promoting macrophage M2-like polarization. Collectively, we provide new specific mechanisms behind HPC regulatory action during cholestatic liver injury, with an active role in cellular interactome and inflammatory response regulation. Moreover, findings prove a key contribution for EGFR signaling jointly with bile acids in HPC-mediated actions.

Bile acids regulation of cellular stress responses in liver physiology and diseases

Bile acids are physiological detergents and signalling molecules that are critically implicated in liver health and diseases. Dysregulation of bile acid homeostasis alters cell function and causes cell injury in chronic liver diseases. Therapeutic agents targeting bile acid synthesis, transport and signalling hold great potential for treatment of chronic liver diseases. The broad cellular and physiological impacts of pharmacological manipulations of bile acid metabolism are still incompletely understood. Recent research has discovered new links of bile acid signalling to the regulation of autophagy and lysosome biology, redox homeostasis and endoplasmic reticulum stress. These are well-conserved mechanisms that allow cells to adapt to nutrient and organelle stresses and play critical roles in maintaining cellular integrity and promoting survival. However, dysregulation of these cellular pathways is often observed in chronic liver diseases, which exacerbates cellular dysfunction to contribute to disease pathogenesis. Therefore, identification of these novel links has significantly advanced our knowledge of bile acid biology and physiology, which is needed to understand the contributions of bile acid dysregulation in disease pathogenesis, establish bile acids as diagnostic markers and develop bile acid-based pharmacological interventions. In this review, we will first discuss the roles of bile acid dysregulation in the pathogenesis of chronic liver diseases, and then discuss the recent findings on the crosstalk of bile acid signalling and cellular stress responses. Future investigations are needed to better define the roles of these crosstalks in regulating cellular function and disease processes.

Bis(2-ethylhexyl)-tetrabromophthalate Poses a Higher Exposure Risk and Induces Gender-Specific Metabolic Disruptions in Zebrafish Liver

Bis(2-ethylhexyl)-tetrabromophthalate (TBPH), a typical novel brominated flame retardant, has been ubiquitously identified in various environmental and biotic media. Consequently, there is an urgent need for precise risk assessment based on a comprehensive understanding of internal exposure and the corresponding toxic effects on specific tissues. In this study, we first investigated the toxicokinetic characteristics of TBPH in different tissues using the classical pseudo-first-order toxicokinetic model. We found that TBPH was prone to accumulate in the liver rather than in the gonad, brain, and muscle of both female and male zebrafish, highlighting a higher internal exposure risk for the liver. Furthermore, long-term exposure to TBPH at environmentally relevant concentrations led to increased visceral fat accumulation, signaling potential abnormal liver function. Hepatic transcriptome analysis predominantly implicated glycolipid metabolism pathways. However, alterations in the profile of associated genes and biochemical indicators revealed gender-specific responses following TBPH exposure. Besides, histopathological observations as well as the inflammatory response in the liver confirmed the development of nonalcoholic fatty liver disease, particularly in male zebrafish. Altogether, our findings highlight a higher internal exposure risk for the liver, enhancing our understanding of the gender-specific metabolic-disrupting potential associated with TBPH exposure.

Liproxstatin-1 Alleviated Ischemia/Reperfusion-Induced Acute Kidney Injury via Inhibiting Ferroptosis

Ferroptosis, as a novel regulable cell death, is characterized by iron overload, glutathione depletion, and an accumulation of lipid peroxides. Recently, it has been discovered that ferroptosis is involved in ischemia/reperfusion (I/R)-induced acute kidney injury (AKI) and plays a crucial role in renal tubular cell death. In this study, we tried to investigate the effect and mechanism of liproxstatin-1 (Lip-1) in I/R-induced AKI and seek the key regulator of ferroptosis in I/R-induced AKI. Mice were administrated with clamping bilateral renal pedicles for 30 min. We found that early growth response 1 (EGR1) might be a key regulator of ferroptosis, and Lip-1 could suppress ferroptosis via EGR1. Meanwhile, Lip-1 could reduce macrophage recruitment and the release of inflammatory cytokines. These findings indicated that Lip-1 alleviated I/R-induced AKI via regulating EGR1, and it might pave the theoretical basis of a new therapeutic strategy for I/R-induced AKI.

Pediatric Cholestatic Diseases: Common and Unique Pathogenic Mechanisms

Cholestasis is the predominate feature of many pediatric hepatobiliary diseases. The physiologic flow of bile requires multiple complex processes working in concert. Bile acid (BA) synthesis and excretion, the formation and flow of bile, and the enterohepatic reuptake of BAs all function to maintain the circulation of BAs, a key molecule in lipid digestion, metabolic and cellular signaling, and, as discussed in the review, a crucial mediator in the pathogenesis of cholestasis. Disruption of one or several of these steps can result in the accumulation of toxic BAs in bile ducts and hepatocytes leading to inflammation, fibrosis, and, over time, biliary and hepatic cirrhosis. Biliary atresia, progressive familial intrahepatic cholestasis, primary sclerosing cholangitis, and Alagille syndrome are four of the most common pediatric cholestatic conditions. Through understanding the commonalities and differences in these diseases, the important cellular mechanistic underpinnings of cholestasis can be greater appreciated.

Restricted intake of sulfur-containing amino acids reversed the hepatic injury induced by excess Desulfovibrio through gut-liver axis

Diet is a key player in gut-liver axis. However, the effect of different dietary patterns on gut microbiota and liver functions remains unclear. Here, we used rodent standard chow and purified diet to mimic two common human dietary patterns: grain and plant-based diet and refined-food-based diet, respectively and explored their impacts on gut microbiota and liver. Gut microbiota experienced a great shift with notable increase in Desulfovibrio, gut bile acid (BA) levels elevated significantly, and liver inflammation was observed in mice fed with the purified diet. Liver inflammation and elevated gut BA levels also occurred in mice fed with the chow diet after receiving Desulfovibrio desulfuricans ATCC 29,577 (DSV). Restriction of sulfur-containing amino acids (SAAs) prevented liver injury mainly through higher hepatic antioxidant and detoxifying ability and reversed the elevated BA levels due to excess Desulfovibrio. Ex vivo fermentation of human fecal microbiota with primary BAs demonstrated that DSV enhanced production of secondary BAs. Higher concentration of both primary and secondary BAs were found in the gut of germ-free mice after receiving DSV. In conclusion, Restriction of SAAs in diet may become an effective dietary intervention to prevent liver injury associated with excess Desulfovibrio in the gut.

Bile acids, gut microbiota, and therapeutic insights in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is a prevalent and aggressive liver malignancy. The interplay between bile acids (BAs) and the gut microbiota has emerged as a critical factor in HCC development and progression. Under normal conditions, BA metabolism is tightly regulated through a bidirectional interplay between gut microorganisms and BAs. The gut microbiota plays a critical role in BA metabolism, and BAs are endogenous signaling molecules that help maintain liver and intestinal homeostasis. Of note, dysbiotic changes in the gut microbiota during pathogenesis and cancer development can disrupt BA homeostasis, thereby leading to liver inflammation and fibrosis, and ultimately contributing to HCC development. Therefore, understanding the intricate interplay between BAs and the gut microbiota is crucial for elucidating the mechanisms underlying hepatocarcinogenesis. In this review, we comprehensively explore the roles and functions of BA metabolism, with a focus on the interactions between BAs and gut microorganisms in HCC. Additionally, therapeutic strategies targeting BA metabolism and the gut microbiota are discussed, including the use of BA agonists/antagonists, probiotic/prebiotic and dietary interventions, fecal microbiota transplantation, and engineered bacteria. In summary, understanding the complex BA-microbiota crosstalk can provide valuable insights into HCC development and facilitate the development of innovative therapeutic approaches for liver malignancy.

Metabolomics and Transcriptomics Analyses of Curcumin Alleviation of Ochratoxin A-Induced Hepatotoxicity

Ochratoxin A (OTA) is one of the mycotoxins that poses a serious threat to human and animal health. Curcumin (CUR) is a major bioactive component of turmeric that provides multiple health benefits. CUR can reduce the toxicities induced by mycotoxins, but the underlying molecular mechanisms remain largely unknown. To explore the effects of CUR on OTA toxicity and identify the key regulators and metabolites involved in the biological processes, we performed metabolomic and transcriptomic analyses of livers from OTA-exposed mice. We found that CUR can alleviate the toxic effects of OTA on body growth and liver functions. In addition, CUR supplementation significantly affects the expressions of 1584 genes and 97 metabolites. Integrated analyses of transcriptomic and metabolomic data showed that the pathways including Arachidonic acid metabolism, Purine metabolism, and Cholesterol metabolism were significantly enriched. Pantothenic acid (PA) was identified as a key metabolite, the exogenous supplementation of which was observed to significantly alleviate the OTA-induced accumulation of reactive oxygen species and cell apoptosis. Further mechanistical analyses revealed that PA can downregulate the expression level of proapoptotic protein BAX, enhance the expression level of apoptosis inhibitory protein BCL2, and decrease the level of phosphorylated extracellular signal-regulated kinase 1/2 (pERK1/2). This study demonstrated that CUR can alleviate the adverse effects of OTA by influencing the transcriptomic and metabolomic profiles of livers, which may contribute to the application of CUR in food and feed products for the prevention of OTA toxicity.

The knockout of cytoglobin 1 in zebrafish (Danio rerio) alters lipid metabolism, iron homeostasis and oxidative stress response

Cytoglobin (Cygb) is an evolutionary ancient heme protein with yet unclear physiological function(s). Mammalian Cygb is ubiquitously expressed in all tissues and is proposed to be involved in reactive oxygen species (ROS) detoxification, nitric oxide (NO) metabolism and lipid-based signaling processes. Loss-of-function studies in mouse associate Cygb with apoptosis, inflammation, fibrosis, cardiovascular dysfunction or oncogenesis. In zebrafish (Danio rerio), two cygb genes exist, cytoglobin 1 (cygb1) and cytoglobin 2 (cygb2). Both have different coordination states and distinct expression sites within zebrafish tissues. The biological roles of the cygb paralogs are largely uncharacterized. We used a CRISPR/Cas9 genome editing approach and generated a knockout of the penta-coordinated cygb1 for in vivo analysis. Adult male cygb1 knockouts develop phenotypic abnormalities, including weight loss. To identify the molecular mechanisms underlying the occurrence of these phenotypes and differentiate between function and effect of the knockout we compared the transcriptomes of cygb1 knockout at different ages to age-matched wild-type zebrafish. We found that immune regulatory and cell cycle regulatory transcripts (e.g. tp53) were up-regulated in the cygb1 knockout liver. Additionally, the expression of transcripts involved in lipid metabolism and transport, the antioxidative defense and iron homeostasis was affected in the cygb1 knockout. Cygb1 may function as an anti-inflammatory and cytoprotective factor in zebrafish liver, and may be involved in lipid-, iron-, and ROS-dependent signaling.

Interleukin-10 disrupts liver repair in acetaminophen-induced acute liver failure

Introduction

Systemic levels of the anti-inflammatory cytokine interleukin 10 (IL-10) are highest in acetaminophen (APAP)-induced acute liver failure (ALF) patients with the poorest prognosis. The mechanistic basis for this counterintuitive finding is not known, as induction of IL-10 is hypothesized to temper the pathological effects of immune cell activation. Aberrant production of IL-10 after severe liver injury could conceivably interfere with the beneficial, pro-reparative actions of immune cells, such as monocytes.

Methods

To test this possibility, we determined whether IL-10 levels are dysregulated in mice with APAP-induced ALF and further evaluated whether aberrant production of IL-10 prevents monocyte recruitment and/or the resolution of necrotic lesions by these cells.

Results

Our studies demonstrate that in mice challenged with 300 mg/kg acetaminophen (APAP), a hepatotoxic dose of APAP that fails to produce ALF (i.e., APAP-induced acute liver injury; AALI), Ly6Chi monocytes were recruited to the liver and infiltrated the necrotic lesions by 48 hours coincident with the clearance of dead cell debris. At 72 hours, IL-10 was upregulated, culminating in the resolution of hepatic inflammation. By contrast, in mice treated with 600 mg/kg APAP, a dose that produces clinical features of ALF (i.e., APAP-induced ALF; AALF), IL-10 levels were markedly elevated by 24 hours. Early induction of IL-10 was associated with a reduction in the hepatic numbers of Ly6Chi monocytes resulting in the persistence of dead cell debris. Inhibition of IL-10 in AALF mice, beginning at 24 hours after APAP treatment, increased the hepatic numbers of monocytes which coincided with a reduction in the necrotic area. Moreover, pharmacologic elevation of systemic IL-10 levels in AALI mice reduced hepatic myeloid cell numbers and increased the area of necrosis.

Discussion

Collectively, these results indicate that during ALF, aberrant production of IL-10 disrupts the hepatic recruitment of monocytes, which prevents the clearance of dead cell debris. These are the first studies to document a mechanistic basis for the link between high IL-10 levels and poor outcome in patients with ALF.

Blockade of CCR5 suppresses paclitaxel-induced peripheral neuropathic pain caused by increased deoxycholic acid

Paclitaxel leads to peripheral neuropathy (paclitaxel-induced peripheral neuropathy [PIPN]) in approximately 50% of cancer patients. At present, there are no effective treatment strategies for PIPN, the mechanisms of which also remain unclear. In this study, we performed microbiome and metabolome analysis of feces and serum from breast cancer patients with different PIPN grades due to paclitaxel treatment. Our analysis reveals that levels of deoxycholic acid (DCA) are highly increased because of ingrowth of Clostridium species, which is associated with severe neuropathy. DCA, in turn, elevates serum level of C-C motif ligand 5 (CCL5) and induces CCL5 receptor 5 (CCR5) overexpression in dorsal root ganglion (DRG) through the bile acid receptor Takeda G-protein-coupled receptor 5 (TGR5), contributing to neuronal hyperexcitability. Consistent with this, administration of CCR5 antagonist maraviroc suppresses the development of neuropathic nociception. These results implicate gut microbiota/bile acids/CCR5 signaling in the induction of PIPN, thus suggesting a target for PIPN treatment.

Bile acids induce IL-1α and drive NLRP3 inflammasome-independent production of IL-1β in murine dendritic cells

Bile acids are amphipathic molecules that are synthesized from cholesterol in the liver and facilitate intestinal absorption of lipids and nutrients. They are released into the small intestine upon ingestion of a meal where intestinal bacteria can modify primary into secondary bile acids. Bile acids are cytotoxic at high concentrations and have been associated with inflammatory diseases such as liver inflammation and Barrett's Oesophagus. Although bile acids induce pro-inflammatory signalling, their role in inducing innate immune cytokines and inflammation has not been fully explored to date. Here we demonstrate that the bile acids, deoxycholic acid (DCA) and chenodeoxycholic acid (CDCA) induce IL-1α and IL-1β secretion in vitro in primed bone marrow derived dendritic cells (BMDCs). The secretion of IL-1β was found not to require expression of NLRP3, ASC or caspase-1 activity; we can't rule out all inflammasomes. Furthermore, DCA and CDCA were shown to induce the recruitment of neutrophils and monocytes to the site of injection an intraperitoneal model of inflammation. This study further underlines a mechanistic role for bile acids in the pathogenesis of inflammatory diseases through stimulating the production of pro-inflammatory cytokines and recruitment of innate immune cells.

Impairment of bile acid metabolism and altered composition by lead and copper in Bufo gargarizans tadpoles

Lead (Pb) and copper (Cu) are two common heavy metal contaminants in environments, and liver is recognized as one of the main target organs for toxicity of Pb and Cu in animal organisms. Bile acids play a critical role in regulating hepatic metabolic homeostasis by activating farnesoid X receptor (Fxr). However, there were few studies on the interactions between bile acids and liver pathology caused by heavy metals. In this work, the histopathological changes, targeted metabolome and transcriptome responses in the liver of Bufo gargarizans tadpoles to Pb and/or Cu were examined. We found that exposure to Pb and/or Cu altered the hepatic bile acid profile, resulting in increased hydrophobicity and toxicity of the bile acid pool. And the expression of genes involved in bile acid metabolism and their downstream signaling pathways in the liver were significantly altered by Pb and/or Cu exposure. The alteration of bile acid profiles and the expression of genes related to bile acid metabolism might induce oxidative stress and inflammation, ultimately inducing hepatocyte injury observed in the histological sections. To our knowledge, this is the first study to provide histological, biochemical, and molecular evidence for establishing the link between Pb and Cu exposure, disturbances in hepatic bile acid metabolism, and liver injury.

Drug induced liver injury - a 2023 update

Drug-Induced Liver Injury (DILI) constitutes hepatic damage attributed to drug exposure. DILI may be categorized as hepatocellular, cholestatic or mixed and might also involve immune responses. When DILI occurs in dose-dependent manner, it is referred to as intrinsic, while if the injury occurs spontaneously, it is termed as idiosyncratic. This review predominately focused on idiosyncratic liver injury. The established molecular mechanisms for DILI include (1) mitochondria dysfunction, (2) increased reactive oxygen species levels, (3) presence of elevated apoptosis and necrosis, (4) and bile duct injuries associated with immune mediated pathways. However, it should be emphasized that the underlying mechanisms responsible for DILI are still unknown. Prevention strategies are critical as incidences occur frequently, and treatment options are limited once the injury has developed. The aim of this review was to utilize retrospective cohort studies from across the globe to gain insight into epidemiological patterns. This review considers (1) what is currently known regarding the mechanisms underlying DILI, (2) discusses potential risk factors and (3) implications of the coronavirus pandemic on DILI presentation and research. Future perspectives are also considered and discussed and include potential new biomarkers, causality assessment and reporting methods.

The CD2v protein of African swine fever virus inhibits macrophage migration and inflammatory cytokines expression by downregulating EGR1 expression through dampening ERK1/2 activity

African swine fever virus (ASFV) is a highly contagious and deadly virus that leads to high mortality rates in domestic swine populations. Although the envelope protein CD2v of ASFV has been implicated in immunomodulation, the molecular mechanisms underlying CD2v-mediated immunoregulation remain unclear. In this study, we generated a stable CD2v-expressing porcine macrophage (PAM-CD2v) line and investigated the CD2v-dependent transcriptomic landscape using RNA-seq. GO terms enrichment analysis and gene set enrichment analysis revealed that CD2v predominantly affected the organization and assembly process of the extracellular matrix. Wound healing and Transwell assays showed that CD2v inhibited swine macrophage migration. Further investigation revealed a significant decrease in the expression of transcription factor early growth response 1 (EGR1) through inhibiting the activity of extracellular signal-regulated kinase 1 and 2 (ERK1/2). Notably, EGR1 knockout in swine macrophages restricted cell migration, whereas EGR1 overexpression in PAM-CD2v restored the ability of macrophage migration, suggesting that CD2v inhibits swine macrophage motility by downregulating EGR1 expression. Furthermore, we performed chromatin immunoprecipitation and sequencing for EGR1 and the histone mark H3K27 acetylation (H3K27ac), and we found that EGR1 co-localized with the activated histone modification H3K27ac neighboring the transcriptional start sites. Further analysis indicated that EGR1 and H3K27ac co-occupy the promoter regions of cell locomotion-related genes. Finally, by treating various derivatives of swine macrophages with lipopolysaccharides, we showed that depletion of EGR1 decreased the expression of inflammatory cytokines including TNFα, IL1α, IL1β, IL6, and IL8, which play essential roles in inflammation and host immune response. Collectively, our results provide new insights into the immunomodulatory mechanism of ASFV CD2v.

Identification of a bile acid and bile salt metabolism-related lncRNA signature for predicting prognosis and treatment response in hepatocellular carcinoma

Bile acids and salts have been shown to play a role in liver carcinogenesis through DNA damage, inflammation, and tumor proliferation. However, the correlation between bile acid metabolism and hepatocellular carcinoma (HCC) prognosis remains unclear. This study aimed to identify a predictive signature of bile acid and bile salt metabolism-related long non-coding RNAs (lncRNAs) for HCC prognosis and treatment response. The study used HCC RNA-sequencing data and corresponding clinical and prognostic data from The Cancer Genome Atlas. A prognostic model consisting of five bile acid and bile salt metabolism-related lncRNAs was developed and evaluated in a training set, a validation set and an external set. The model demonstrated good performance in predicting HCC prognosis and was shown to be an independent biomarker for prognosis. Additionally, our study revealed a significant association between the signature and immune cell infiltration, as well as its predictive value for therapeutic responses to both immunotherapy and chemotherapy. Furthermore, three LncRNAs (LUCAT1, AL031985.3 and AC015908.3) expression levels in our signature were validated through qRT-PCR in a cohort of 50 pairs of HCC patient tumor samples and corresponding adjacent non-tumor samples, along with 10 samples of normal liver tissue adjacent to benign lesions. These findings suggest that this novel bile acid and bile salt metabolism-related lncRNA signature can independently predict the prognosis of patients with HCC and may be utilized as a potential predictor of response to treatment in this setting.

Melatonin attenuates cholestatic liver injury via inhibition of the inflammatory response

Melatonin, an indole neurohormone secreted mainly by the pineal gland, has been found to be involved in a variety of liver diseases. However, the underlying mechanism by which melatonin ameliorates cholestatic liver injury is not fully understood. In this study, we investigated the mechanism by which melatonin attenuates cholestatic liver injury via inhibition of the inflammatory response. We measured the levels of serum melatonin in patients with obstructive cholestasis (n = 9), patients with primary biliary cholangitis (PBC) (n = 11), and control patients (n = 7). We performed experiments with C57BL/6 J mice treated with 3,5-diethoxycarbonyl-1,4-dihydrocollidine (DDC) and melatonin to verify the role of melatonin in the mouse model of cholestasis. Primary mouse hepatocytes were used for in vitro studies to study the mechanisms of action of melatonin in cholestasis. The levels of serum melatonin were markedly increased and negatively correlated with serum markers of liver injury in cholestatic patients. As expected, oral administration of melatonin significantly attenuated cholestasis-induced liver inflammation and fibrosis in 0.1% DDC diet-fed mice. Further mechanistic studies in cholestatic mice and primary hepatocytes revealed that melatonin reduced the conjugate BA-stimulated expression of cytokines (e.g. Ccl2, Tnfα, and Il6) through the ERK/Egr1 signalling pathway in these models. The levels of serum melatonin are significantly elevated in cholestatic patients. Melatonin treatment ameliorates cholestatic liver injury by suppressing the inflammatory response in vivo and in vitro. Therefore, melatonin is a promising novel therapeutic strategy for cholestasis.

Genetic predisposition of the gastrointestinal microbiome and primary biliary cholangitis: a bi-directional, two-sample Mendelian randomization analysis

Background

The gut-liver axis indicates a close relationship between the gastrointestinal microbiome (GM) and primary biliary cholangitis (PBC). However, the causality of this relationship remains unknown. This study investigates the causal relationship between the GM and PBC using a bidirectional, two-sample Mendelian randomization (MR) analysis.

Methods

Genome-wide association data for GM and PBC were obtained from public databases. The inverse-variance weighted method was the primary method used for MR analysis. Sensitivity analyses were conducted to assess the stability of the MR results. A reverse MR analysis was performed to investigate the possibility of reverse causality.

Results

Three bacterial taxa were found to be causally related to PBC. Class Coriobacteriia (odds ratio (OR) = 2.18, 95% confidence interval (CI): 1.295-3.661, P< 0.05) and order Coriobacteriales (OR = 2.18, 95% CI: 1.295-3.661, P<0.05) were associated with a higher risk of PBC. Class Deltaproteobacteria (OR = 0.52, 95% CI: 0.362-0.742, P< 0.05) had a protective effect on PBC. There was no evidence of reverse causality between PBC and the identified bacterial taxa.

Conclusion

Previously unrecognized taxa that may be involved in the pathogenesis of PBC were identified in this study, confirming the causality between the GM and PBC. These results provide novel microbial targets for the prevention and treatment of PBC.

The molecular insights of bile acid homeostasis in host diseases

Bile acids (BAs) function as detergents promoting nutrient absorption and as hormones regulating nutrient metabolism. Most BAs are key regulatory factors of physiological activities, which are involved in the regulation of glucose, lipid, and drug metabolisms. Hepatic and intestinal diseases have close connections with the systemic cycling disorders of BAs. The abnormal in BA absorption came up with overmuch BAs could be involved in the pathophysiology of liver and bowel and metabolic disorders such as fatty liver diseases and inflammatory bowel diseases. The primary BAs (PBAs), which are synthesized in the liver, can be transformed into the secondary BAs (SBAs) by gut microbiota. The transformation processes are tightly associated with the gut microbiome and the host endogenous metabolism. The BA biosynthesis gene cluster bile-acid-inducible operon is essential for modulating BA pool, gut microbiome composition, and the onset of intestinal inflammation. This forms a bidirectional interaction between the host and its gut symbiotic ecosystem. The subtle changes in the composition and abundance of BAs perturb the host physiological and metabolic activity. Therefore, maintaining the homeostasis of BAs pool contributes to the balance of the body's physiological and metabolic system. Our review aims to dissect the molecular mechanisms underlying the BAs homeostasis, assess the key factors sustaining the homeostasis and the role of BA acting on host diseases. By linking the BAs metabolic disorders and their associated diseases, we illustrate the effects of BAs homeostasis on health and potential clinical interventions can be taken under the latest research findings.

Hepatic inflammatory responses in liver fibrosis

Chronic liver diseases such as nonalcoholic fatty liver disease (NAFLD) or viral hepatitis are characterized by persistent inflammation and subsequent liver fibrosis. Liver fibrosis critically determines long-term morbidity (for example, cirrhosis or liver cancer) and mortality in NAFLD and nonalcoholic steatohepatitis (NASH). Inflammation represents the concerted response of various hepatic cell types to hepatocellular death and inflammatory signals, which are related to intrahepatic injury pathways or extrahepatic mediators from the gut-liver axis and the circulation. Single-cell technologies have revealed the heterogeneity of immune cell activation concerning disease states and the spatial organization within the liver, including resident and recruited macrophages, neutrophils as mediators of tissue repair, auto-aggressive features of T cells as well as various innate lymphoid cell and unconventional T cell populations. Inflammatory responses drive the activation of hepatic stellate cells (HSCs), and HSC subsets, in turn, modulate immune mechanisms via chemokines and cytokines or transdifferentiate into matrix-producing myofibroblasts. Current advances in understanding the pathogenesis of inflammation and fibrosis in the liver, mainly focused on NAFLD or NASH owing to the high unmet medical need, have led to the identification of several therapeutic targets. In this Review, we summarize the inflammatory mediators and cells in the diseased liver, fibrogenic pathways and their therapeutic implications.

Regulation of Immune Homeostasis, Inflammation, and HIV Persistence by the Microbiome, Short-Chain Fatty Acids, and Bile Acids

Despite antiretroviral therapy (ART), people living with human immunodeficiency virus (HIV) (PLWH) continue to experience chronic inflammation and immune dysfunction, which drives the persistence of latent HIV and prevalence of clinical comorbidities. Elucidating the mechanisms that lead to suboptimal immunity is necessary for developing therapeutics that improve the quality of life of PLWH. Although previous studies have found associations between gut dysbiosis and immune dysfunction, the cellular/molecular cascades implicated in the manifestation of aberrant immune responses downstream of microbial perturbations in PLWH are incompletely understood. Recent literature has highlighted that two abundant metabolite families, short-chain fatty acids (SCFAs) and bile acids (BAs), play a crucial role in shaping immunity. These metabolites can be produced and/or modified by bacterial species that make up the gut microbiota and may serve as the causal link between changes to the gut microbiome, chronic inflammation, and immune dysfunction in PLWH. In this review, we discuss our current understanding of the role of the microbiome on HIV acquisition and latent HIV persistence despite ART. Further, we describe cellular/molecular cascades downstream of SCFAs and BAs that drive innate or adaptive immune responses responsible for promoting latent HIV persistence in PLWH. This knowledge can be used to advance HIV cure efforts.