Pharmacological modulation of cholesterol 7α-hydroxylase (CYP7A1) as a therapeutic strategy for hypercholesterolemia

Identification of potential metabolic biomarkers and immune cell infiltration for metabolic associated steatohepatitis by bioinformatics analysis and machine learning

BACKGROUND

Metabolic associated steatohepatitis (MASH) represents a severe subtype of metabolic associated fatty liver disease (MASLD), with an increased risk of progression to cirrhosis and hepatocellular carcinoma. The nomenclature shift from nonalcoholic steatohepatitis (NASH)/nonalcoholic fatty liver disease (NAFLD) to MASH/MASLD, underscores the pivotal role of metabolic factors in disease progression. Diagnosis of MASH currently hinges on liver biopsy, a procedure whose invasive nature limits its clinical utility. This study aims to identify and validate metabolism-related genes (MRGs) markers for the non-invasive diagnosis of MASH.

METHODS

This study extracted multiple datasets from the GEO database to identify metabolism-related differentially expressed genes (MRDEGs). Protein-Protein Interaction (PPI) network and machine learning algorithms, including Least Absolute Shrinkage and Selection Operator (LASSO) regression, Support Vector Machine-Recursive Feature Elimination (SVM-RFE), and Random Forest (RF), were applied to screen for signature MRDEGs. The diagnostic performance of these MRDEGs was evaluated using the Receiver Operating Characteristic (ROC) curve and further validated using independent external datasets. Additionally, enrichment analysis was performed to uncover key driver pathways in MASH. The infiltration levels of various immune cell types were assessed using single sample Gene Set Enrichment Analysis (ssGSEA). Finally, Spearman correlation analysis confirmed the association between signature genes and immune cells.

RESULTS

We successfully identified seven signature MRDEGs, including CYP7A1, GCK, AKR1B10, HPRT1, GPD1, FADS2, and ENO3, through PPI network analysis and machine learning algorithms. The gene model displayed exceptional diagnostic performance in the training and validation cohorts, as evidenced by the area under ROC curve (AUC) exceeding 0.9. Further enrichment analysis revealed that signature MEDEGs were primarily involved in multiple biological pathways related to glucose and lipid metabolism. Immune infiltration analysis indicated a significant increase in the infiltration levels of activated CD8 T cells, gamma-delta T cells, natural killer cells, and CD56bright NK cells in patients with MASH.

CONCLUSION

This study successfully identified seven signature MRDEGs as significant diagnostic biomarkers for MASH. The findings not only offer novel strategies for non-invasive diagnosis of MASH but also highlight the substantial role of immune cell infiltration in the progression of MASH.

Crosstalk Between Bile Acids and Intestinal Epithelium: Multidimensional Roles of Farnesoid X Receptor and Takeda G Protein Receptor 5

Bile acids and their corresponding intestinal epithelial receptors, the farnesoid X receptor (FXR), the G protein-coupled bile acid receptor (TGR5), play crucial roles in the physiological and pathological processes of intestinal epithelial cells. These acids and receptors are involved in the regulation of intestinal absorption, signal transduction, cellular proliferation and repair, cellular senescence, energy metabolism, and the modulation of gut microbiota. A comprehensive literature search was conducted using PubMed, employing keywords such as bile acid, bile acid receptor, FXR (nr1h4), TGR5 (gpbar1), intestinal epithelial cells, proliferation, differentiation, senescence, energy metabolism, gut microbiota, inflammatory bowel disease (IBD), colorectal cancer (CRC), and irritable bowel syndrome (IBS), with a focus on publications available in English. This review examines the diverse effects of bile acid signaling and bile receptor pathways on the proliferation, differentiation, senescence, and energy metabolism of intestinal epithelial cells. Additionally, it explores the interactions between bile acids, their receptors, and the microbiota, as well as the implications of these interactions for host health, particularly in relation to prevalent intestinal diseases. Finally, the review highlights the importance of developing highly specific ligands for FXR and TGR5 receptors in the context of metabolic and intestinal disorders.

Gut Microbiota and Its Metabolite Taurine-β-Muricholic Acid Contribute to Antimony- and/or Copper-Induced Liver Inflammation

Antimony and copper can contaminate vegetables and enter the human body through the digestive tract, inducing severe and extensive biotoxicity. However, the role of bile acids (BAs) in the pathogenesis of liver inflammation by antimony or copper has not been elucidated. Our results indicated that antimony and/or copper induced liver inflammation, causing the disruption of gut microbiota, with the down-regulation of probiotics and up-regulation of harmful bacteria closely correlated to liver inflammation. Targeted metabolomics of BAs showed that antimony and/or copper significantly up-regulated the levels of taurine-β-muricholic acid (T-β-MCA) in serum and liver, which was due to the reduction of Lactobacillus spp. A farnesoid X receptor (FXR) antagonist, T-β-MCA inhibited the FXR-SHP pathway in liver and FXR-FGF15 pathway in ileum, thereby promoting the transcription of cholesterol 7-alpha hydroxylase (CYP7A1) and increasing total bile acid concentrations, ultimately leading to liver inflammation. These findings provide new insights into the underlying mechanisms of antimony- and/or copper-induced liver inflammation.

Combined action of dietary-based approaches and therapeutic agents on cholesterol metabolism and main related diseases

BACKGROUND

Dyslipidaemia is among the major causes of severe diseases and, despite being well-established, the hypocholesterolaemic therapies still face significant concerns about potential side effects (such as myopathy, myalgia, liver injury digestive problems, or mental fuzziness in some people taking statins), interaction with other drugs or specific foods. Accordingly, this review describes the latest developments in the most effective therapies to control and regulate dyslipidaemia.

SCOPE AND APPROACH

Herein, the metabolic dynamics of cholesterol and their integration with the current therapies: statins, bile acid sequestrants, fibrates, niacin, proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitors, reconstituted high-density lipoprotein (rHDL), or anti-inflammatory and immune-modulating therapies), were compared focusing their effectiveness, patients' adhesion and typical side-effects. Likewise, the interaction of these therapies with recommended dietary habits, focusing functional foods and nutraceuticals uptake were also considered.

KEY FINDINGS AND CONCLUSIONS

Since none of the current therapeutic alternatives represent an ideal solution (mainly due to side-effects or patients' tolerance), the potential adjuvant action of selected diets (and other healthy habits) was proposed as a way to improve the cholesterol-lowering effectiveness, while reducing the adverse effects caused by dose-increase or continuous uptake of alternating therapeutic agents. In general, the relevance of well-adapted diets must be acknowledged and their potential effects must be exhorted among patients, who need to be aware of the associated multifactorial advantages.

Global Levels and Variations of Cholesterol and Polar Lipids of Human Milk: A Systematic Review and Meta-analysis

Polar lipids and cholesterol are vital structural components of the milk fat globule membrane, playing a crucial role in infant growth and development; however, systematic global reports on their content in human milk are currently lacking. This study conducted a systematic literature search in Chinese and English databases, including 69,392 human milk samples from 96 studies. A random-effects model based on global data was used to assess the content of total lipids, cholesterol, gangliosides, and phospholipids in human milk and their variations with the lactation stage, geographical region, and sample year. The mean contents of total lipids, cholesterol, and total phospholipids were 2774.15 mg/100 g (95% CI: 2614.88, 2933.42 mg/100 g), 21.15 mg/100 g (18.35, 23.95 mg/100 g), and 70.72 mg/100 g (68.84, 72.60 mg/100 g), respectively, with gangliosides GM3 and GD3 at 0.63 mg/100 g (0.54, 0.72 mg/100 g) and 0.34 mg/100 g (0.32, 0.36 mg/100 g). The major phospholipids SM, PC, PE, PS, and PI averaged 24.19 mg/100 g (23.17 and 25.21 mg/100 g), 21.27 mg/100 g (19.92 and 22.62 mg/100 g), 18.28 mg/100 g (17.46 and 19.10 mg/100 g), 2.86 mg/100 g (2.32 and 3.40 mg/100 g), and 2.12 mg/100 g (1.75 and 2.49 mg/100 g). With the progression of lactation, total lipids, gangliosides, and most phospholipids (SM, PC, PS, PI) increased, while cholesterol and PE decreased. Over the years, total lipids, gangliosides, and PE showed an upward trend, whereas cholesterol and most phospholipids declined. Human milk from Europe had lower total lipid and cholesterol levels compared with other regions. While the total phospholipid content did not show significant regional differences (P > 0.05), variations in phospholipid composition were observed. These findings emphasize the importance of understanding spatiotemporal changes in human milk lipids to develop personalized nutrition strategies that support optimal infant growth and development.

The Protective Effect of Limosilactobacillus fermentum FZU501 Against Alcohol-Induced Liver Injury in Mice via Gut Microbiota-Liver Axis

As a probiotic strain isolated from Hongqu rice wine (a traditional Chinese fermented food), Limosilactobacillus fermentum FZU501 (designated as Lf) demonstrates exceptional gastric acid and bile salt tolerance, showing potential application as a functional food. The aim of this study was to investigate the protective effect of dietary Lf intervention on alcohol-induced liver injury (ALI) in mice. The results demonstrated that oral administration of Lf effectively ameliorated alcohol-induced lipid metabolism disorders by reducing the serum levels of TC, TG and LDL-C and increasing the serum levels of HDL-C. In addition, oral administration of Lf effectively prevented alcohol-induced liver damage by increasing the hepatic activities of antioxidant enzymes (CAT, SOD, GSH-Px) and alcohol-metabolizing enzymes (ADH and ALDH). Interestingly, 16S amplicon sequencing showed that oral administration of Lf increased the number of Prevotella, Lachnospiraceae_NK4A136_group and Lactobacillus, but decreased the proportion of Faecalibaculum, Adlercreutzia and Alistipes in the intestines of mice that consumed excessive alcohol, which was highly associated with improved liver function. As revealed by liver untargeted metabolomics studies, oral Lf clearly changed liver metabolic profiles, with the signature biomarkers mainly involving purine metabolism, taurine metabolism, tryptophan, alanine, aspartic acid and glutamate metabolism, etc. Additionally, Lf intervention regulated liver gene transcription in over-drinking mice for cholesterol metabolism, bile acid metabolism, fatty acid β-oxidation, alcohol metabolism and oxidative stress. Taken together, the above research results provide solid scientific support for the biological activity of Lf in ameliorating alcohol-induced liver metabolism disorder and intestinal microbiota imbalance.

Crosstalk between bile acids and gut microbiota: a potential target for precancerous lesions of gastric cancer

As a critical juncture in the pathological continuum from gastritis to gastric cancer, precancerous lesions of gastric cancer (PLGC) are increasingly prevalent, significantly undermining the health of the global population. The primary constituents of bile, specifically bile acids (BAs), disrupt the equilibrium of gastric hormone secretion and compromise the structural integrity of the gastric mucosa, thereby facilitating gastric oncogenesis. Moreover, gut microbiota modulate host physiological and pathological processes through immune response regulation, metabolic pathway interference, and direct interaction with gastric tumor cells. Extensive research has elucidated that the metabolic dysregulation of BAs and gut microbiota, in concert with the resultant impairment of the gastric mucosa, are central to the pathogenesis of PLGC. In anticipation of future clinical preventive and therapeutic strategies, this review collates recent insights into the roles of BAs and gut bacteria in PLGC, examining their interplay and significance in the pathogenic mechanism of PLGC.

Broccoli (Brassica oleracea L. var. italica Planch) alleviates metabolic-associated fatty liver disease through regulating gut flora and lipid metabolism via the FXR/LXR signaling pathway

The increased consumption of dietary fats contributes to the development of MAFLD (metabolic fatty liver disease). The ability of broccoli to enhance lipid metabolism has attracted researchers' attention. Researchers fed C57BL/6 mice a 12-week HFD to ensure the induction of MAFLD. The findings indicated that broccoli floret juice could effectively relieve MAFLD. Broccoli is helpful for reducing weight, blood glucose levels, fat accumulation, and insulin resistance associated with MAFLD and reduces the concentrations of TC, TG, LDL-C, GOT, GPT, IL-1β, IL-6, CCL4, and MCP1. Broccoli can increase the concentration of HDL-C, CAT, GSH-Px, SOD, and T-AOC, relieve inflammation and hepatic and ileum damage, and improve the antioxidant capacity of the body. Also, broccoli can optimize the structure of intestinal flora, promote the growth of Allobaculum, Muribaculaceae, Akkermansia, Eubacterium, and Bacteroides, and reduce bile acid deposition. In addition, the FXR/LXRα signaling system is impacted by broccoli, which is capable of raising the average levels of expression of the Fxr, SHP, and Cyp7a1 genes and proteins and reducing those of the genes for Fasn, Lpin 1, Dgat 2, Scd1, LXRα, and SREBP-1c.

Exploring the metabolic patterns and response mechanisms of bile acids during fasting: A study with poultry as an example

Fasting is beneficial to alleviate fatty liver, lose weight and improve reproductive function. However, previous studies have shown that, during fasting, disorders of bile acid metabolism were strongly associated with intestinal inflammation. The physiological and biochemical parameters and gene expression of multiple tissues of chickens at every critical time node were measured by ELISA and qPCR. In addition, association analysis was performed based on liver transcriptome sequencing and cecum metabolome data. At the cellular level, the regulatory effects of cecal metabolites on host bile acid metabolism were verified. During fasting, hepatic FXR-SHP-CYP7A1 and ileum-hepatic FXR-SHP-FGF15/19-FGFR4-CYP7A1 negative feedback pathways were activated to inhibit hepatic bile acid synthesis. The ileum FXR-SHP-ASBT pathways are activated, hindered the ileal bile reflux. At the same time, it promotes the secretion of bile acids and cholesterol in the liver, accelerates the utilization of H2O and CO2, to maintain liver homeostasis during fasting. In addition, enhanced gallbladder contraction and increased hunger were observed in laying hens during fasting. At the cellular level, the correlation between CYP7A1 and L-valine was verified, revealing that cecal metabolites of laying hens was enabled to regulate host bile acid metabolism. This study explored the metabolic patterns of bile acids during fasting and identified the main reasons for the accumulation of bile acids in the cecum, which provides a basis for fasting research and offers a reference for the formulation of fasting protocols.

Effects of Fingered Citron (Citrus medica var. sarcodactylis) Essential Oil on Improvement in Diet-Induced Hyperlipidemia Syrian Hamsters

Preventing hyperlipidemia and the risk of cardiovascular disease are attractive to public health. Essential oils are extremely promising nutrients for use in the treatment of hyperlipidemia, whose effectiveness is closely related to its volatile composition. We extracted fingered citron essential oil (FCEO) with steam distillation, analyzed the chemical composition, and evaluated its effects on hyperlipidemia. We identified 25 volatile compounds of FCEO with GC/MS, of which the main constituents were limonene and γ-terpinene. This study explored the protective effects of FCEOs against diet-induced hyperlipidemia Syrian hamsters. FCEOs treatment ranges from 0.03% to 0.05% with a daily diet. As of 12 weeks later, we found that the administration of the FCEOs improved the serum total cholesterol (TC), triglyceride (TG), and low-density lipoprotein cholesterol (LDL-C) levels (p < 0.05). Further, LDL-C/HDL-C (high-density lipoprotein cholesterol) ratios were significantly reduced (39.02-68.07 vs. 80.27). Simultaneously, the FCEOs had improved lipid metabolism and histopathology in the liver. These actions suggest the potential of FCEO as a valuable source of nutraceuticals in diet-based therapies.

Exploring potential plasma drug targets for cholelithiasis through multiancestry Mendelian randomization

BACKGROUND

Cholelithiasis poses significant health and economic burdens, necessitating novel pharmacological targets to enhance treatment efficacy.

METHOD

Based on genome-wide association analysis studies, the authors performed a two-sample Mendelian randomization (MR) analysis based on plasma proteomics to explore potential drug targets in European (n Case =40 191 and n Control =361 641) and Asian (n Case =9305 and n Control =168 253) populations. The authors confirmed the directionality and robust correlation of the drug targets with the results through reverse MR analysis, Steiger filtering, Bayesian colocalization, phenotype scanning, and replication in multiple databases. Further exploration of the safety and possible mechanisms of action of phenome-wide MR analysis and protein-protein interactions (PPIs) as individual drug targets was performed.

RESULTS

Our proteomics-based MR analyses suggested that FUT3 (OR=0.87; 95% CI: 0.84-0.89; P =4.70×10 -32 ), NOE1 (OR=0.58; 95% CI: 0.52-0.66; P =4.21×10 -23 ), UGT1A6 (OR=0.68; 95% CI: 0.64-0.73; P =9.58×10 -30 ), and FKBP52 (OR=1.75; 95% CI: 1.37-2.24; P =8.61×10 -6 ) were potential drug targets in Europeans, whereas KLB (OR=1.11; 95% CI: 1.07-1.16; P =7.59×10 -7 ) and FGFR4 (OR=0.94; 95% CI: 0.91-0.96; P =4.07×10 -6 ) were valid targets in East Asians. There was no reverse causality for these drug targets. Evidence from Bayesian colocalization analyses supported that exposure and outcome shared consistent genetic variables. Phenome-wide MR analysis suggested the potential deleterious effects of NOE1 and FGFR4. PPI analysis confirmed the pathways associated with the potential targets involved in bile acid metabolism.

CONCLUSIONS

Genetically predicted levels of the plasma proteins FUT3, NOE1, UGT1A6, and FKBP52 have the potential as prospective targets in Europeans. Moreover, the plasma levels of KLB and FGFR4 may serve as potential targets for the treatment of cholelithiasis in East Asians.

New finding based on Comparative Toxicogenomics Database: Hepatic YY1 mediates drug-induced liver injury

BACKGROUND

YY1 plays a crucial part in the onset and progression of numerous liver diseases, yet the significant contribution of YY1 to drug-induced liver injury (DILI) appears to have been underestimated by researchers.

PURPOSE

To reveal the underlying role of YY1 in DILI.

METHOD

The compounds that interact with YY1 were queried in the Comparative Toxicogenomics Database (CTD), with the majority found to be hepatotoxic, which includes certain widely used drugs. Molecular docking and SPR characterized the robust binding of hepatotoxic compounds to YY1. The duty of YY1 in DILI was investigated in Diosbulbin B (DIOB), a recently identified hepatotoxic compound that tightly associates with YY1, and further validated on ANIT, LCA, APAP, and CDDP. Transcriptomic analysis disclosed the underlying mechanisms involved in DIOB-induced liver injury. RT-qPCR, immunohistochemistry, immunofluorescence, western blotting, and cellular transfection techniques were employed to validate the specific mechanism.

RESULTS

Among the 94 compounds affecting YY1 expression in the CTD, 59 compounds exhibited hepatotoxicity, showing close interactions with YY1 and almost consistent binding sites by molecular docking. The SPR validated the tough binding of several hepatotoxic compounds to YY1, including five FDA-approved hepatotoxic drugs. Mechanistically, the involvement of YY1 in DILI was uncovered through the cholestasis lens, mice hepatic YY1 was up-regulated by hepatotoxic DIOB and transcriptionally inhibited FXR and its downstream BSEP and MRP2 expression, initiating early in cholestatic liver injury and persisting to drive the progression of cholestasis. ANIT and LCA-induced model of cholestasis provided evidence for the hypothesis that YY1 frequently mediates drug induced cholestasis (DIC). APAP and CDDP indicated that YY1 may also be involved in hepatocellular and mixed type DILI.

CONCLUSION

YY1 widely mediated the development of DIC and also might be engaged in other types of DILI. YY1 presented a common target for hepatotoxic medications and the targeting of liver YY1 for drug development may offer a novel approach for managing DILI.

Preparation and characterization of Tobacco polysaccharides and its modulation on hyperlipidemia in high-fat-diet-induced mice

This study aimed to investigate the structural properties of tobacco polysaccharide (TP) and its mechanism of modulating hyperlipidemia in high-fat diet-induced mice. The structural properties of TP were characterized by FT-IR, 1HNMR, SEM, AFM and thermogravimetric analysis. And the regulatory mechanism of TP on lipid metabolism was investigated in hyperlipidemia mice. These results showed that TP had a high composition of reducing monosaccharide and the glycosidic bond type was α-glycosidic bond. The intervention by TP resulted in a significant reduction of body weight and improvement in lipid accumulation. And the modulation mechanism by which TP ameliorated the abnormalities of lipid metabolism was associated with the expression levels of lipid metabolism-related genes and serum exosomes miRNA-128-3p, as well as the modulation of structure and abundance of the gut microbiota in mice. In addition, TP treatment significantly increased the content of short-chain fatty acids (SCFAs) in mice feces. The results of molecular docking and dual-luciferase assay exhibited a good interaction between propionic acid and PPAR-α, and it was hypothesized that the interaction might further ameliorate the hyperlipidemia. Therefore, TP can regulate the expression levels of lipid metabolism-related genes through miRNAs from serum exosomes and SCFAs from gut microbiota.

Beyond conventional treatment: ASGR1 Leading the new era of hypercholesterolemia management

Cardiovascular disease (CVD) remains a leading cause of mortality worldwide, with hypercholesterolemia being a major risk factor. Although various lipid-lowering therapies exist, many patients fail to achieve optimal cholesterol control, highlighting the need for novel therapeutic approaches. ASGR1 (asialoglycoprotein receptor 1), predominantly expressed on hepatocytes, has emerged as a key regulator of cholesterol metabolism and low-density lipoprotein (LDL) clearance. This receptor's ability to regulate lipid homeostasis positions it as a promising target for therapeutic intervention in hypercholesterolemia and related cardiovascular diseases. This review critically examines the biological functions and regulatory mechanisms of ASGR1 in cholesterol metabolism, with a focus on its potential as a therapeutic target for hypercholesterolemia and related cardiovascular diseases. By analyzing recent advances in ASGR1 research, this article explores its role in liver-specific pathways, the implications of ASGR1 variants in CVD risk, and the prospects for developing ASGR1-targeted therapies. This review aims to provide a foundation for future research and clinical applications in hypercholesterolemia management.

Ferulic Acid Alleviates Lipid and Bile Acid Metabolism Disorders by Targeting FASN and CYP7A1 in Iron Overload-Treated Mice

Iron overload is a common complication in various chronic liver diseases, including non-alcoholic fatty liver disease (NAFLD). Lipid and bile acid metabolism disorders are regarded as crucial hallmarks of NAFLD. However, effects of iron accumulation on lipid and bile acid metabolism are not well understood. Ferulic acid (FA) can chelate iron and regulate lipid and bile acid metabolism, but its potential to alleviate lipid and bile acid metabolism disorders caused by iron overload remains unclear. Here, in vitro experiments, iron overload induced oxidative stress, apoptosis, genomic instability, and lipid deposition in AML12 cells. FA reduced lipid and bile acid synthesis while increasing fatty acid β-oxidation and bile acid export, as indicated by increased mRNA expression of PPARα, Acox1, Adipoq, Bsep, and Shp, and decreased mRNA expression of Fasn, Acc, and Cyp7a1. In vivo experiments, FA mitigated liver injury in mice caused by iron overload, as indicated by reduced AST and ALT activities, and decreased iron levels in both serum and liver. RNA-seq results showed that differentially expressed genes were enriched in biological processes related to lipid metabolism, lipid biosynthesis, lipid storage, and transport. Furthermore, FA decreased cholesterol and bile acid contents, downregulated lipogenesis protein FASN, and bile acid synthesis protein CYP7A1. In conclusion, FA can protect the liver from lipid and bile acid metabolism disorders caused by iron overload by targeting FASN and CYP7A1. Consequently, FA, as a dietary supplement, can potentially prevent and treat chronic liver diseases related to iron overload by regulating lipid and bile acid metabolism.

Silicon-Enriched Meat Ameliorates Diabetic Dyslipidemia by Improving Cholesterol, Bile Acid Metabolism and Ileal Barrier Integrity in Rats with Late-Stage Type 2 Diabetes

Silicon as a functional ingredient of restructured meat (RM) shows antidiabetic and hypocholesterolemic effects in a type 2 diabetes mellitus (T2DM) rat model. The present paper investigated the mechanisms involved in this cholesterol-lowering effect by studying the impact of silicon-RM consumption on bile acid (BA) and cholesterol metabolism. In addition, the main effects of cecal BA and short-chain fatty acids derived from the microbiota on intestinal barrier integrity were also tested. Rats were fed an RM high-saturated-fat, high-cholesterol diet (HSFHCD) combined with a low dose of streptozotocin plus nicotinamide injection (LD group) and for an 8 wk. period. Silicon-RM was included in the HSFHCD as a functional food (LD-Si group). An early-stage T2DM group fed a high-saturated-fat diet (ED group) was used as a reference. Silicon decreased the BA pool with a higher hydrophilic BA profile and a lower ability to digest fat and decreased the damaging effects, increasing the occludin levels and the integrity of the intestinal barrier. The ileal BA uptake and hepatic BA synthesis through CYP7A1 were reduced by FXR/FGF15 signaling activation. The silicon up-regulated the hepatic and ileal FXR and LXRα/β, improving transintestinal cholesterol (TICE), biliary BA and cholesterol effluxes. The inclusion of silicon in meat products could be used as a new therapeutic nutritional tool in the treatment of diabetic dyslipidemia.

Sex differences and testosterone interfere with the structure of the gut microbiota through the bile acid signaling pathway

Background

The gut microbiome has a significant impact on human wellness, contributing to the emergence and progression of a range of health issues including inflammatory and autoimmune conditions, metabolic disorders, cardiovascular problems, and psychiatric disorders. Notably, clinical observations have revealed that these illnesses can display differences in incidence and presentation between genders. The present study aimed to evaluate whether the composition of gut microbiota is associated with sex-specific differences and to elucidate the mechanism.

Methods

16S-rRNA-sequencing technology, hormone analysis, gut microbiota transplantation, gonadectomy, and hormone treatment were employed to investigate the correlation between the gut microbiome and sex or sex hormones. Meanwhile, genes and proteins involved bile acid signaling pathway were analyzed both in the liver and ileum tissues.

Results

The composition and diversity of the microbiota from the jejunum and feces and the level of sex hormones in the serum differed between the sexes in young and middle-aged Sprague Dawley (SD) rats. However, no similar phenomenon was found in geriatric rats. Interestingly, whether in young, middle-aged, or old rats, the composition of the microbiota and bacterial diversity differed between the jejunum and feces in rats. Gut microbiota transplantation, gonadectomy, and hormone replacement also suggested that hormones, particularly testosterone (T), influenced the composition of the gut microbiota in rats. Meanwhile, the mRNA and protein level of genes involved bile acid signaling pathway (specifically SHP, FXR, CYP7A1, and ASBT) exhibited gender-specific differences, and T may play a significant role in mediating the expression of this pathway.

Conclusion

Sex-specific differences in the structure of the gut microbiota are mediated by T through the bile acid signaling pathway, pointing to potential targets for disease prevention and management techniques by indicating that sex differences and T levels may alter the composition of the gut microbiota via the bile acid signaling pathway.

Highland Barley Alleviates High-Fat Diet-Induced Obesity and Liver Injury Through the IRS2/PI3K/AKT Signaling Pathway in Rats

Objectives: Highland barley (HB) consumption offers numerous health benefits; however, its impact on glycolipid metabolism abnormalities induced by a high-fat diet remains unclear. Consequently, this study aimed to investigate the therapeutic effects and underlying molecular mechanisms of HB in the context of obesity; Methods: Rats were fed either a high-fat diet (HFD) to induce obesity or a standard diet (SD) for six weeks. The rats in the HFD group were randomly assigned into five groups: HFD+HFD, HFD+SD, and low (30%), medium (45%), and high (60%) doses of the HB diet for an additional ten weeks. Analyses of serum lipid profiles, liver histology, transcriptomes, and untargeted metabolomes were conducted; Results: HB intake resulted in decreased weight gain, reduced feed intake, lower serum triglyceride and cholesterol levels, and diminished hepatic lipid accumulation. It also improved insulin and fasting blood glucose levels, and antioxidant capacity in the HFD-fed rats. Transcriptome analysis revealed that HB supplementation significantly suppressed the HFD-induced increase in the expression of Angptl8, Apof, CYP7A1, GDF15, Marveld1, and Nr0b2. Furthermore, HB supplementation reversed the HFD-induced decrease in Pex11a expression. Untargeted metabolome analysis indicated that HB primarily influenced the pentose phosphate pathway, the Warburg effect, and tryptophan metabolism. Additionally, integrated transcriptome and metabolome analyses demonstrated that the treatments affected the expression of genes associated with glycolipid metabolism, specifically ABCG8, CYP2C12, CYP2C24, CYP7A1, and IRS2. Western blotting confirmed that HB supplementation impacted the IRS2/PI3K/AKT signaling pathway; Conclusions: HB alleviates HFD-induced obesity and liver injury in an obese rat model possibly through the IRS2/PI3K/Akt signaling pathway.

Biological Mechanisms of Aflatoxin B1-Induced Bile Metabolism Abnormalities in Ducklings

This study investigated the effects and biological mechanisms of aflatoxin B1 (AFB1) on the health and bile metabolism of ducklings. Forty-eight 1-day-old ducklings were randomly assigned to two groups, with six replicates per group. The control group was fed a basic diet, while the AFB1 group received a diet containing 90 µg/kg of AFB1. The experiment lasted for 2 weeks. The results showed that 90 µg/kg AFB1 caused abnormal bile metabolism; damaged liver cell nuclei and mitochondria; and significantly decreased body weight, average daily weight gain, and levels of albumin, total protein, cholesterol, total superoxide dismutase, glutathione peroxidase, and glutathione. It also significantly increased feed conversion efficiency, along with alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase, total bile acids, and malondialdehyde levels. In the liver, the expression levels of CYP7A1, SCD, and other genes were significantly upregulated, while BSEP, FASN, HMGCR, CAT, and other genes were significantly downregulated. In conclusion, AFB1 causes abnormal bile metabolism and impairs the overall health and liver function of ducklings. Its mechanism of action may involve changes in gene expression related to bile acid metabolism, lipid metabolism, oxidative damage, and cancer pathways.

Bifidobacterium longumBL-19 inhibits oxidative stress and inflammatory damage in the liver of mice with NAFLD by regulating the production of butyrate in the intestine

Nonalcoholic fatty liver disease (NAFLD) is a common chronic liver disease, but there is currently no effective treatment method. Probiotics have been used as an adjunct therapy for NAFLD, but the mechanism is not clear. This study used Bifidobacterium longum BL19 (BL-19) to treat the NAFLD mice induced by a high-fat diet, and explored the treatment mechanism through gut microbiota and serum metabolomics techniques. We found that BL-19 effectively prevented rapid weight gain in NAFLD mice and reduced their overall food and energy intake, decreased liver inflammatory factors expressions, and increased the bile acid synthetase enzyme CYP7A1 and superoxide dismutase. After BL-19 treatment, the abundances of butyric acid bacteria (Oscillospira and Coprococcus) in the feces of mice increased significantly, and the concentration of butyric acid also increased significantly. We believe that BL-19 promotes the production of butyrate in the intestines, which in turn regulates the activity of CYP7A1 in the liver and bile acid synthesis, ultimately treating liver inflammation and lipid accumulation in NAFLD mice. Serum metabolomics results indicated that BL-19 affected multiple pathways related to inflammation and lipid metabolism in NAFLD mice. These findings suggest that BL-19 shows promise as an adjunct therapy for NAFLD, as it can significantly improve oxidative stress, reduce inflammation in the liver, and decrease lipid accumulation.

On the Cholesterol Raising Effect of Coffee Diterpenes Cafestol and 16-O-Methylcafestol: Interaction with Farnesoid X Receptor

The diterpene cafestol represents the most potent cholesterol-elevating compound known in the human diet, being responsible for more than 80% of the effect of coffee on serum lipids, with a mechanism still not fully clarified. In the present study, the interaction of cafestol and 16-O-methylcafestol with the stabilized ligand-binding domain (LBD) of the Farnesoid X Receptor was evaluated by fluorescence and circular dichroism. Fluorescence quenching was observed with both cafestol and 16-O-methylcafestol due to an interaction occurring in the close environment of the tryptophan W454 residue of the protein, as confirmed by docking and molecular dynamics. A conformational change of the protein was also observed by circular dichroism, particularly for cafestol. These results provide evidence at the molecular level of the interactions of FXR with the coffee diterpenes, confirming that cafestol can act as an agonist of FXR, causing an enhancement of the cholesterol level in blood serum.