Sodium Butyrate Supplementation Inhibits Hepatic Steatosis by Stimulating Liver Kinase B1 and Insulin-Induced Gene

Butyrate Ameliorates Graves' Orbitopathy Through Regulating Orbital Fibroblast Phenotypes and Gut Microbiota

Purpose

Graves' orbitopathy (GO), the common extrathyroidal complication of Graves' disease (GD), is characterized by orbital fibroblast stimulation, adipogenesis, and hyaluronan production. Recently, gut microbiota and its metabolites have garnered attention for their possible involvement in GO.

Methods

This study utilized an animal model of GO and examined the effects of butyrate treatment on orbital fibroblast cells and gut microbiota. Ex vivo experiments were performed using orbital fibroblasts derived from healthy patients' and patients' with GO orbital tissue to evaluate vitality, activation, and adipogenesis in response to butyrate treatment. Gut microbiota diversity was also analyzed in butyrate-treated and untreated GO mice.

Results

In human orbital fibroblasts, butyrate treatment dramatically decreased the vitality of GO-derived fibroblasts without harming normal fibroblasts. Butyrate prevented activation and fibrotic processes induced by transforming growth factor beta 1 (TGF-β1) in GO and normal fibroblasts. Additionally, butyrate reduced lipid droplet formation and downregulated lipogenic markers in GO and normal orbital fibroblasts, inhibiting adipogenesis. In the GO mouse model, butyrate therapy improved orbital histological abnormalities and normalized serum thyroid hormone and antibody levels. The intestinal microbiome of butyrate-treated GO mice also changed significantly, with a reduction in certain bacteria (Bifidobacterium, GCA-900066575, and Parabacteroides) and an increase in others (Bacteroides and Rikenellaceae_RC9).

Conclusions

Butyrate ameliorates several of the symptoms of GO, lowering GO orbital fibroblast viability, adipogenesis, and TGF-β1-induced fibrosis without damaging normal fibroblasts. Butyrate normalizes thyroid function in a GO mouse model, improves histopathological alterations, and transforms gut microbiota populations, proving its potential in treating GO through the gut-thyroid axis.

Structural characterization of a α-d-glucan from Ginkgo biloba seeds and its protective effects on non-alcoholic fatty liver disease in mice

Nonalcoholic fatty liver disease (NAFLD) poses a great global challenge to public health, yet it holds promise for amelioration through plant-derived polysaccharide. Ginkgo biloba seeds have long been used as medicine and food, which has potential benefits for various chronic diseases. However, the protective role of Ginkgo biloba seed polysaccharide against NAFLD remains unclear. In this study, we isolated and purified polysaccharide (GBSP-2) from Ginkgo biloba seeds. GBSP-2 is composed of α-d-glucopyranose residues, which are interconnected with α-d-glucopyranose units linked by (1→4) bonds, (1→4,6) bonds and (1→3,4) bonds, the ratio distribution is 15:1:1. By studying a mouse model, we investigated the effect of GBSP-2 (100 or 200 mg/kg) on high-fat-diet-induced NAFLD. We demonstrated that GBSP-2 significantly alleviated NAFLD, as evidenced by reduced hepatic steatosis, decreased inflammation, improved oxidative stress and ameliorative glucolipid metabolic disorders. Furthermore, GBSP-2 mitigated gut microbiota disturbance of NAFLD mice and markedly increased the abundance of Akkermansia, Romboutsia, Lactobacillus and Bacteroides. Mechanistically, GBSP-2 could activate AMPK/ACC signaling pathway to inhibit lipid synthesis by generating 3,4-dihydroxyphenylpropionic acid (DHPPA). Overall, these findings suggest that GBSP-2 plays a multi-channel and multi-target role in improving NAFLD through the gut-liver axis.

Ethyl Lactate Ameliorates Hepatic Steatosis and Acute-on-Chronic Liver Injury in Alcohol-Associated Liver Disease by Inducing Fibroblast Growth Factor 21

Aberrant upregulation of hepatic lipogenesis induced by chronic and excessive alcohol consumption is a critical driver of the progression of alcohol-associated liver disease (ALD), however, no effective approaches inhibiting lipogenesis are currently available for treating ALD patients. Moreover, little is known about whether and how nonethanol ingredients in alcoholic beverages regulate the pathogenesis of ALD. Here the discovery of a small molecule that activates the production and secretion of fibroblast growth factor 21 (FGF21) is reported. It is shown that the activator ethyl lactate, a nonethanol ingredient found in distilled liquors, ameliorates alcoholic hepatosteatosis, inflammation and acute-on-chronic liver injury by stimulating FGF21. In response to chronic-plus-binge ethanol feeding or fasting, ethyl lactate mimics lipogenesis lowering effects by stimulating FGF21 production through the NAD+-dependent deacetylase sirtuin 1 (SIRT1) signaling pathway. These ethyl lactate-mediated beneficial effects are abolished by inhibition of SIRT1 through injection of EX527. Importantly, FGF21 deficiency in hepatocytes blocks the downregulation of lipogenesis by ethyl lactate and exacerbates alcoholic steatosis, inflammation and liver injury. The regulatory mechanism is discussed during the pathophysiological conditions and suggests new lines of research into the therapeutic use of a foodborne small molecule ethyl lactate.

Lactobacillus sp. for the Attenuation of Metabolic Dysfunction-Associated Steatotic Liver Disease in Mice

Probiotics are studied for their therapeutic potential in the treatment of several diseases, including metabolic dysfunction-associated steatotic liver disease (MASLD). Part of the significant progress made in understanding the pathogenesis of steatosis has come from identifying the complex interplay between the gut microbiome and liver function. Recently, probiotics have shown beneficial effects for the treatment and prevention of steatosis and MASLD in rodent models and in clinical trials. Numerous studies have demonstrated the promising potential of lactic acid bacteria, especially the genus Lactobacillus. Lactobacillus is a prominent bile acid hydrolase bacterium that is involved in the biotransformation of bile acids. This genus' modulation of the gut microbiota also contributes to overall gut health; it controls gut microbial overgrowth, shapes the intestinal bile acid pool, and alleviates inflammation. This narrative review offers a comprehensive summary of the potential of Lactobacillus in the gut-liver axis to attenuate steatosis and MASLD. It also highlights the roles of Lactobacillus in hepatic lipid metabolism, insulin resistance, inflammation and fibrosis, and bile acid synthesis in attenuating MASLD.

Ameliorative effects of Trichosanthes kirilowii Maxim. seed oil on hyperlipidemia rats associated with the regulation of gut microbiology and metabolomics

The mechanisms underlying the ameliorative effects of polyunsaturated fatty acids (PUFAs) on metabolic disorders induced by a high-fat diet (HFD) remain poorly unclear. In this study, we investigated the anti-hyperlipidemic effects of Trichosanthes kirilowii Maxim. (T. kirilowii) seed oil rich in conjugated linolenic acid in HFD-induced hyperlipidemic rats, by the gut microbiome, cecum bile acids (BAs), and serum metabolomics. The results showed that T. kirilowii seed oil improved dyslipidemia, hepatic steatosis, oxidative stress, and inflammatory responses in HFD-induced rats. Meanwhile, T. kirilowii seed oil inhibited sterol regulatory element-binding protein 1c (SREBP-1c) mediated fatty acid synthesis and upregulated cholesterol 7-alpha hydroxylase (CYP7A1) mediated hepatic cholesterol metabolism to exert hypolipidemic effects. The administration of high dose T. kirilowii seed oil (THD) improved gut microbiota dysbiosis, increased the relative abundance of beneficial bacteria Romboutsia and unidentified_Oscillospiraceae, and decreased the relative abundance of Christensenellaceae_R-7 group, Phascolarctobacterium, and Bacteroides in HFD-induced rats. T. kirilowii seed oil reduced the accumulation of cecum primary BAs in HFD-induced rats. In addition, THD reversed the HFD-induced changes in 24 serum metabolites including leucine, isoleucine, acetylcarnitine, and glucose. Metabolic pathway enrichment analysis of the differential metabolites revealed that valine, leucine and isoleucine metabolism, butanoate metabolism, citrate cycle, and glycolysis were potential metabolic pathways involved in the anti-hyperlipidemic effects of T. kirilowii seed oil. In conclusion, this study found that dietary T. kirilowii seed oil alleviated gut microbiota dysbiosis and improved metabolic disorders in hyperlipidemic rats. This provides new insights into the anti-hyperlipidemic mechanism by which other families of PUFAs are derived from different plants.

A polysaccharide from edible red seaweed Bangia fusco-purpurea prevents obesity in high-fat diet-induced C57BL/6 mice

The study aimed to investigate the impacts of a polysaccharide (BFP) from Bangia fusco-purpurea on high-fat diet (HFD)-induced obesity in C57BL/6 mice, as well as its underlying mechanisms. Our results showed that orally administrated BFP was more effective than inulin (INU) in reducing body weight and fat accumulation in obese mice, indicating its anti-obesity effect. BFP effectively improved the compositions and metabolites of intestinal microbiota in obese mice, leading to enhanced energy metabolism and lipid metabolism, thus contributing to its anti-obesity effect. Notably, the better anti-obesity effect of BFP compared to INU was attributed to their varying degrees of modulation of specific intestinal microbial taxa, such as Clostridium and Aerococcus, as well as the regulation of differential metabolites (including biotin, piperine, G6P, etc.) also varied. Also, both in vitro (3T3-L1 preadipocytes) and in vivo (HFD-induced obese mice) models confirmed that BFP achieved anti-obesity effect attributed to enhance energy metabolism, promote lipolysis, increase fatty acid oxidation, and inhibit adipogenesis via activating the AMP-activated protein kinase and Acetyl-CoA carboxylase signaling pathways and suppressing the peroxisome proliferator-activated receptor γ expression. Our findings suggest that BFP has the potential to be used as prebiotics, dietary agents, and nutritional supplements against obesity.

Postbiotics as Antiinflammatory and Immune-Modulating Bioactive Compounds in Metabolic Dysfunction-Associated Steatotic Liver Disease

Postbiotics, defined as products or metabolic byproducts secreted by live bacteria or released after bacterial lysis, are emerging as promising therapeutic agents for metabolic dysfunction-associated steatotic liver disease (MASLD). This review explores the antiinflammatory and immunomodulatory properties of various postbiotics, including exopolysaccharides, lipoteichoic acid, short-chain fatty acids, hydrogen sulfide, polyamines, tryptophan derivatives, and polyphenol metabolites. These compounds have demonstrated potential in mitigating steatotic liver infiltration, reducing inflammation, and slowing fibrosis progression in preclinical studies. Notably, postbiotics exert their beneficial effects by modulating gut microbiota composition, enhancing intestinal barrier function, optimizing lipid metabolism, reducing hepatic inflammation and steatosis, and exhibiting hepatoprotective properties. However, translating these findings into clinical practice requires well-designed trials to validate efficacy and safety, standardize production and characterization, and explore personalized approaches and synergistic effects with other therapeutic modalities. Despite challenges, the unique biological properties of postbiotics, such as enhanced safety compared to probiotics, make them attractive candidates for developing novel nutritional interventions targeting the multifactorial pathogenesis of MASLD. Further research is needed to establish their clinical utility and potential to improve liver and systemic outcomes in this increasingly prevalent condition.

Gut microbiome and metabolome signatures in liver cirrhosis-related complications

BACKGROUND/AIMS

Shifts in the gut microbiota and metabolites are interrelated with liver cirrhosis progression and complications. However, causal relationships have not been evaluated comprehensively. Here, we identified complication-dependent gut microbiota and metabolic signatures in patients with liver cirrhosis.

METHODS

Microbiome taxonomic profiling was performed on 194 stool samples (52 controls and 142 cirrhosis patients) via V3-V4 16S rRNA sequencing. Next, 51 samples (17 controls and 34 cirrhosis patients) were selected for fecal metabolite profiling via gas chromatography mass spectrometry and liquid chromatography coupled to time-of-flight mass spectrometry. Correlation analyses were performed targeting the gut-microbiota, metabolites, clinical parameters, and presence of complications (varices, ascites, peritonitis, encephalopathy, hepatorenal syndrome, hepatocellular carcinoma, and deceased).

RESULTS

Veillonella bacteria, Ruminococcus gnavus, and Streptococcus pneumoniae are cirrhosis-related microbiotas compared with control group. Bacteroides ovatus, Clostridium symbiosum, Emergencia timonensis, Fusobacterium varium, and Hungatella_uc were associated with complications in the cirrhosis group. The areas under the receiver operating characteristic curve (AUROCs) for the diagnosis of cirrhosis, encephalopathy, hepatorenal syndrome, and deceased were 0.863, 0.733, 0.71, and 0.69, respectively. The AUROCs of mixed microbial species for the diagnosis of cirrhosis and complication were 0.808 and 0.847, respectively. According to the metabolic profile, 5 increased fecal metabolites in patients with cirrhosis were biomarkers (AUROC >0.880) for the diagnosis of cirrhosis and complications. Clinical markers were significantly correlated with the gut microbiota and metabolites.

CONCLUSION

Cirrhosis-dependent gut microbiota and metabolites present unique signatures that can be used as noninvasive biomarkers for the diagnosis of cirrhosis and its complications.

Transcriptomic Landscape Analysis Reveals a Persistent DNA Damage Response in Metabolic Dysfunction-associated Steatohepatitis Post-dietary Intervention

Background and Aims

Metabolic dysfunction-associated steatotic liver disease (MASLD) and its more advanced form, metabolic dysfunction-associated steatohepatitis, have emerged as the most prevalent liver diseases worldwide. Currently, lifestyle modification is the foremost guideline-recommended management strategy for MASLD. However, it remains unclear which detrimental signals persist in MASLD even after disease remission. Thus, we aimed to examine the persistent changes in liver transcriptomic profiles following this reversal.

Methods

Male C57BL/6J mice were divided into three groups: Western diet (WD) feeding, chow diet (CD) feeding, or diet reversal from WD to CD. After 16 weeks of feeding, RNA sequencing was performed on the mice's livers to identify persistent alterations characteristic of MASLD. Additionally, RNA sequencing databases containing high-fat diet-fed P53-knockout mice and human MASLD samples were utilized.

Results

WD-induced MASLD triggered persistent activation of the DNA damage response (DDR) and its primary transcription factor, P53, long after the resolution of the hepatic phenotype through dietary reversal. Elevated levels of P53 might promote apoptosis, thereby exacerbating metabolic dysfunction-associated steatohepatitis, as they strongly correlated with hepatocyte ballooning, an indicator of apoptosis activation. Moreover, P53 knockout in mice led to downregulated expression of apoptosis signaling in the liver. Mechanistically, P53 may regulate apoptosis by transcriptionally activating the expression of apoptosis-enhancing nuclease (AEN). Consistently, P53, AEN, and the apoptosis process all exhibited persistently elevated expression and showed a strong inter-correlation in the liver following dietary reversal.

Conclusions

The liver demonstrated upregulation of DDR signaling and the P53-AEN-apoptosis axis both during and after exposure to WD. Our findings provide new insights into the mechanisms of MASLD relapse, highlighting DDR signaling as a promising target to prevent MASLD recurrence.

The hepatoprotective effect of sodium butyrate on hepatic inflammatory injury mediated by the NLRP3 inflammatory pathway in subchronic fluoride-exposed mice

BACKGROUND

Excessive subchronic fluoride exposure can cause severe damage to detoxification organs, including the liver. Sodium butyrate has anti-inflammatory, antitumor, antioxidant and immunomodulatory properties. However, relatively few studies have investigated the effects of sodium butyrate on liver injury caused by subchronic fluoride exposure. The purpose of this research was to investigate the effect and mechanism of sodium butyrate on fluoride-induced hepatic inflammatory injury via the expression of nod-like receptor protein 3 (NLRP3).

METHODS

Mice were subjected to randomization into four groups, control group (C), fluorosis group (F), sodium butyrate alone group (S), and treatment group (Y). The mice in groups F and F + S drank 100 mg/L sodium fluoride-containing distilled water freely every day. After fluoride exposure lasted for 3 months, the mice in group S and F + S were gavaged with sodium butyrate daily at a concentration of 1000 mg/kg. Following the treatment regimen, liver specimens were collected for analysis. The mRNA and protein expression levels of inflammatory factors and NLRP3 and its downstream gene were measured by RT-qPCR and western blotting.

RESULTS

The histological hematoxylin and eosin (H&E) staining of liver showed that the subchronic fluoride-exposed group were chronic inflammation. The liver of treatment group were less vacuolar degeneration and inflammatory infiltration. The results of the biochemical assay showed that the subchronic fluoride-exposed group were liver injury. In addition, the detection of oxidative stress indicators showed that chronic subchronic fluoride exposure could lead to an increase in the level of oxidative stress in the liver, and the treatment alleviated this increase. RT-qPCR results showed that compared with those in the control group, the mRNA levels of the inflammatory factors TNF-α, IL-6 and IL-1β, the NLRP3 inflammasome and its downstream factors NLRP3, caspase-1, gasdermin D (GSDMD) and IL-18 increased in the liver tissue of mice in the subchronic fluoride-exposed group. Sodium butyrate released inflammatory factors during subchronic fluoride exposure and inhibited the protein expression of activated NLRP3 to a certain extent.

CONCLUSIONS

Sodium butyrate may play a protective role by antagonizing the production of activated inflammasomes and their downstream inflammatory factors in the livers of subchronic fluoride-exposed mice.

Intermittent fasting, exercise, and dietary modification induce unique transcriptomic signatures of multiple tissues governing metabolic homeostasis during weight loss and rebound weight gain

Obesity and its related metabolic diseases bring great challenges to public health. In-depth understanding on the efficacy of weight-loss interventions is critical for long-term weight control. Our study demonstrated the comparable efficacy of exercise (EX), intermittent fasting (IF), or the change of daily diet from an unhealthy to a normal chow (DR) for weight reduction, but largely divergently affected metabolic status and transcriptome of subcutaneous fat, scapular brown fat, skeletal muscles and liver in high-fat-high-fructose diet (HFHF) induced obese mice. EX and IF reduced systematic inflammation, improved glucose and lipid metabolism in liver and muscle, and amino acid metabolism and thermogenesis in adipose tissues. EX exhibited broad regulatory effects on TCA cycle, carbon metabolism, thermogenesis, propanoate-, fatty acid and amino acid metabolism across multiple tissues. IF prominently affected genes involved in mitophagy and autophagy in adipose tissues and core genes involved in butanoate metabolism in liver. DR, however, failed to improve metabolic homeostasis and biological dysfunctions in obese mice. Notably, by exploring potential inter-organ communication, we identified an obesity-resistant-like gene profile that were strongly correlated with HFHF induced metabolic derangements and could predict the degree of weight regain induced by the follow-up HFHF diet. Among them, 12 genes (e.g., Gdf15, Tfrc, Cdv3, Map2k4, and Nqo1) were causally associated with human metabolic traits, i.e., BMI, body fat mass, HbA1C, fasting glucose, and cholesterol. Our findings provide critical groundwork for improved understanding of the impacts of weight-loss interventions on host metabolism. The identified genes predicting weight regain may be considered regulatory targets for improving long-term weight control.

Effect of Supplementation of a Butyrate-Based Formula in Individuals with Liver Steatosis and Metabolic Syndrome: A Randomized Double-Blind Placebo-Controlled Clinical Trial

Postbiotics could exert different metabolic activities in animal models of non-alcoholic fatty liver disease (NAFLD) and in humans affected by metabolic syndrome. This is a randomized, double-blind, placebo-controlled, parallel-group clinical trial that enrolled a sample of 50 Caucasian healthy individuals with NAFLD, defined as liver steatosis, and metabolic syndrome. After a 4-week run-in, the enrolled individuals were randomized to take a food for special medical purposes with functional release, one tablet a day, containing calcium butyrate (500 mg/tablet), zinc gluconate (zinc 5 mg/tablet), and vitamin D3 (500 IU/tablet), or an identical placebo for 3 months. Liver and metabolic parameters were measured at baseline and at the end of the study. No subject experienced any adverse events during the trial. In both groups, a significant decrease in total cholesterol (TC) and triglycerides (TG) plasma levels was observed at the randomization visit vs. pre-run-in visit (p < 0.05). Regarding liver parameters, after treatment, the fatty liver index (FLI) improved significantly vs. baseline values (p < 0.05) and vs. placebo group (p < 0.05) in the active treatment group, and the hepatic steatosis index (HSI) improved significantly vs. baseline values (p < 0.05). Moreover, after active treatment, TC, TG, and gamma-glutamyl transferase (gGT) improved significantly vs. baseline values (p < 0.05), and TC and TG improved vs. placebo group (p < 0.05), as well. In the placebo group, liver parameters remained unchanged after treatment; only TG improved significantly vs. baseline values (p < 0.05). In our study, we observed that the butyrate-based formula improved FLI and plasma lipid patterns in individuals affected by liver steatosis and metabolic syndrome.

Lysophosphatidylcholine trigger myocardial injury in diabetic cardiomyopathy via the TLR4/ZNF480/AP-1/NF-kB pathway

Background

Diabetic cardiomyopathy (DC), a frequent complication of type 2 diabetes mellitus (T2DM), is mainly associated with severe adverse outcomes. Previous research has highlighted the role of Lysophosphatidylcholine (LPC) in inducing myocardial injury; however, the specific mechanisms through which LPC mediate such injury in DC remain elusive. The existing knowledge gap underscores the need for additional clarification. Consequently, this study aimed to explore the impact and underlying mechanisms of LPC on myocardial injury in DC.

Methods

A total of 55 patients diagnosed with T2DM and 62 healthy controls were involved. A combination of 16s rRNA sequencing, metabolomic analysis, transcriptomic RNA-sequencing (RNA-seq), and whole exome sequencing (WES) was performed on fecal and peripheral blood samples collected from the participants. Following this, correlation analysis was carried out, and the results were further validated through the mouse model of T2DM.

Results

Four LPC variants distinguishing T2DM patients from healthy controls were identified, all of which were upregulated in T2DM patients. Specifically, Lysopc (16:0, 2 N isoform) and LPC (16:0) exhibited a positive correlation with nuclear factor kappa B subunit 2 (NFKB2) and a negative correlation with Zinc finger protein 480 (ZNF480) Furthermore, the expression levels of Toll-like receptor 4 (TLR4), c-Jun, c-Fos, and NFKB2 were upregulated in the peripheral blood of T2DM patients and in the myocardial tissue of T2DM mice, whereas ZNF480 expression level was downregulated. Lastly, myocardial injury was identified in T2DM mice.

Conclusions

The results indicated that LPC could induce myocardial injury in DC through the TLR4/ZNF480/AP-1/NF-kB pathway, providing a precise target for the clinical diagnosis and treatment of DC.

Microbial metabolites affect tumor progression, immunity and therapy prediction by reshaping the tumor microenvironment (Review)

Several studies have indicated that the gut microbiome and tumor microbiota may affect tumors. Emerging metabolomics research illustrates the need to examine the variations in microbial metabolite composition between patients with cancer and healthy individuals. Microbial metabolites can impact the progression of tumors and the immune response by influencing a number of mechanisms, including modulation of the immune system, cancer or immune‑related signaling pathways, epigenetic modification of proteins and DNA damage. Microbial metabolites can also alleviate side effects and drug resistance during chemotherapy and immunotherapy, while effectively activating the immune system to exert tumor immunotherapy. Nevertheless, the impact of microbial metabolites on tumor immunity can be both beneficial and harmful, potentially influenced by the concentration of the metabolites or the specific cancer type. The present review summarizes the roles of various microbial metabolites in different solid tumors, alongside their influence on tumor immunity and treatment. Additionally, clinical trials evaluating the therapeutic effects of microbial metabolites or related microbes on patients with cancer have been listed. In summary, studying microbial metabolites, which play a crucial role in the interaction between the microbiota and tumors, could lead to the identification of new supplementary treatments for cancer. This has the potential to improve the effectiveness of cancer treatment and enhance patient prognosis.

Endometriosis, Pain, and Related Psychological Disorders: Unveiling the Interplay among the Microbiome, Inflammation, and Oxidative Stress as a Common Thread

Endometriosis (EM), a chronic condition in endometrial tissue outside the uterus, affects around 10% of reproductive-age women, significantly affecting fertility. Its prevalence remains elusive due to the surgical confirmation needed for diagnosis. Manifesting with a range of symptoms, including dysmenorrhea, dyschezia, dysuria, dyspareunia, fatigue, and gastrointestinal discomfort, EM significantly impairs quality of life due to severe chronic pelvic pain (CPP). Psychological manifestations, notably depression and anxiety, frequently accompany the physical symptoms, with CPP serving as a key mediator. Pain stems from endometrial lesions, involving oxidative stress, neuroinflammation, angiogenesis, and sensitization processes. Microbial dysbiosis appears to be crucial in the inflammatory mechanisms underlying EM and associated CPP, as well as psychological symptoms. In this scenario, dietary interventions and nutritional supplements could help manage EM symptoms by targeting inflammation, oxidative stress, and the microbiome. Our manuscript starts by delving into the complex relationship between EM pain and psychological comorbidities. It subsequently addresses the emerging roles of the microbiome, inflammation, and oxidative stress as common links among these abovementioned conditions. Furthermore, the review explores how dietary and nutritional interventions may influence the composition and function of the microbiome, reduce inflammation and oxidative stress, alleviate pain, and potentially affect EM-associated psychological disorders.

Digestive dynamics: Unveiling interplay between the gut microbiota and the liver in macronutrient metabolism and hepatic metabolic health

Although the liver is the largest metabolic organ in the body, it is not alone in functionality and is assisted by "an organ inside an organ," the gut microbiota. This review attempts to shed light on the partnership between the liver and the gut microbiota in the metabolism of macronutrients (i.e., proteins, carbohydrates, and lipids). All nutrients absorbed by the small intestines are delivered to the liver for further metabolism. Undigested food that enters the colon is metabolized further by the gut microbiota that produces secondary metabolites, which are absorbed into portal circulation and reach the liver. These microbiota-derived metabolites and co-metabolites include ammonia, hydrogen sulfide, short-chain fatty acids, secondary bile acids, and trimethylamine N-oxide. Further, the liver produces several compounds, such as bile acids that can alter the gut microbial composition, which can in turn influence liver health. This review focuses on the metabolism of these microbiota metabolites and their influence on host physiology. Furthermore, the review briefly delineates the effect of the portosystemic shunt on the gut microbiota-liver axis, and current understanding of the treatments to target the gut microbiota-liver axis.

Gut microbiota induced epigenetic modifications in the non-alcoholic fatty liver disease pathogenesis

Non-alcoholic fatty liver disease (NAFLD) represents a growing global health concern that can lead to liver disease and cancer. It is characterized by an excessive accumulation of fat in the liver, unrelated to excessive alcohol consumption. Studies indicate that the gut microbiota-host crosstalk may play a causal role in NAFLD pathogenesis, with epigenetic modification serving as a key mechanism for regulating this interaction. In this review, we explore how the interplay between gut microbiota and the host epigenome impacts the development of NAFLD. Specifically, we discuss how gut microbiota-derived factors, such as lipopolysaccharides (LPS) and short-chain fatty acids (SCFAs), can modulate the DNA methylation and histone acetylation of genes associated with NAFLD, subsequently affecting lipid metabolism and immune homeostasis. Although the current literature suggests a link between gut microbiota and NAFLD development, our understanding of the molecular mechanisms and signaling pathways underlying this crosstalk remains limited. Therefore, more comprehensive epigenomic and multi-omic studies, including broader clinical and animal experiments, are needed to further explore the mechanisms linking the gut microbiota to NAFLD-associated genes. These studies are anticipated to improve microbial markers based on epigenetic strategies and provide novel insights into the pathogenesis of NAFLD, ultimately addressing a significant unmet clinical need.

Short-Chain Fatty Acids and Human Health: From Metabolic Pathways to Current Therapeutic Implications

The gastrointestinal tract is home to trillions of diverse microorganisms collectively known as the gut microbiota, which play a pivotal role in breaking down undigested foods, such as dietary fibers. Through the fermentation of these food components, short-chain fatty acids (SCFAs) such as acetate, propionate, and butyrate are produced, offering numerous health benefits to the host. The production and absorption of these SCFAs occur through various mechanisms within the human intestine, contingent upon the types of dietary fibers reaching the gut and the specific microorganisms engaged in fermentation. Medical literature extensively documents the supplementation of SCFAs, particularly butyrate, in the treatment of gastrointestinal, metabolic, cardiovascular, and gut-brain-related disorders. This review seeks to provide an overview of the dynamics involved in the production and absorption of acetate, propionate, and butyrate within the human gut. Additionally, it will focus on the pivotal roles these SCFAs play in promoting gastrointestinal and metabolic health, as well as their current therapeutic implications.

Lacticaseibacillus rhamnosus HF01 fermented yogurt alleviated high-fat diet-induced obesity and hepatic steatosis via the gut microbiota-butyric acid-hepatic lipid metabolism axis

The objective of this study was to investigate the anti-obesity effects and underlying mechanism of Lacticaseibacillus rhamnosus HF01 fermented yogurt (HF01-Y). Herein, obesity was induced in mice through a high-fat diet and the changes in the gut microbiota were evaluated using 16S rRNA gene sequencing, combined with the expression levels of the liver AMPK signaling pathway to analyze the potential relationship between HF01-Y-mediated gut microbiota and obesity. The results showed that supplementation with HF01-Y improved obesity-related phenotypes in mice, including reduced body weight, improved serum lipid profiles, and decreased hepatic lipid droplet formation. In addition, HF01-Y altered the composition of the gut microbiota in obese mice, significantly upregulated norank_f__Muribaculaceae, unclassified_c__Clostridia, Blautia, unclassified_o__Bacteroidales, and Rikenellaceae_RC9_gut_group, while downregulating unclassified_f__Desulfovibrionaceae, Colidextribacter, and unclassified_f__Oscillospiraceae. These alterations led to an increase of the cecum butyric acid content, which in turn indirectly promoted the activation of the AMPK signaling pathway, subsequently, inhibited fat synthesis, and promoted fatty acid oxidation related gene expression. Therefore, HF01-Y was likely to alleviate hepatic fat and relieve obesity by modulating the gut microbiota-butyric acid-hepatic lipid metabolism axis, ultimately promoting host health.

Sodium butyrate alleviates free fatty acid-induced steatosis in primary chicken hepatocytes via the AMPK/PPARα pathway

Fatty liver hemorrhagic syndrome (FLHS) is a prevalent metabolic disorder observed in egg-laying hens, characterized by fatty deposits and cellular steatosis in the liver. Our preliminary investigations have revealed a marked decrease in the concentration of butyric acid in the FLHS strain of laying hens. It has been established that sodium butyrate (NaB) protects against metabolic disorders. However, the underlying mechanism by which butyrate modulates hepato-lipid metabolism to a great extent remains unexplored. In this study, we constructed an isolated in vitro model of chicken primary hepatocytes to induce hepatic steatosis by free fatty acids (FFA). Our results demonstrate that treatment with NaB effectively mitigated FFA-induced hepatic steatosis in chicken hepatocytes by inhibiting lipid accumulation, downregulating the mRNA expression of lipo-synthesis-related genes (sterol regulatory element binding transcription factor 1 (SREBF1), acetyl-CoA carboxylase 1(ACC1), fatty acid synthase (FASN), stearoyl-CoA desaturase 1 (SCD1), liver X receptor α (LXRα), 3-hydroxy-3-methylglutaryl-CoA reductase (HMGR)) (P < 0.05), and upregulating the mRNA and protein expression of AMP-activated protein kinase α1 (AMPKα1), peroxisome proliferator-activated receptor α (PPARα), and carnitine palmitoyl-transferase 1A (CPT1A) (P < 0.05). Moreover, AMPK and PPARα inhibitors (Compound C (Comp C) and GW6471, respectively) reversed the protective effects of NaB against FFA-induced hepatic steatosis by blocking the AMPK/PPARα pathway, leading to lipid droplet accumulation and triglyceride (TG) contents in chicken primary hepatocytes. With these findings, NaB can alleviate hepatocyte lipoatrophy injury by activating the AMPK/PPARα pathway, promoting fatty acid oxidation, and reducing lipid synthesis in chicken hepatocytes, potentially being able to provide new ideas for the treatment of FLHS.

Phosphorylation: new star of pathogenesis and treatment in steatotic liver disease

Steatotic liver disease poses a serious threat to human health and has emerged as one of the most significant burdens of chronic liver disease worldwide. Currently, the research mechanism is not clear, and there is no specific targeted drug for direct treatment. Phosphorylation is widely regarded as the most common type of protein modification, closely linked to steatotic liver disease in previous studies. However, there is no systematic review to clarify the relationship and investigate from the perspective of phosphorylation. Phosphorylation has been found to mainly regulate molecule stability, affect localization, transform molecular function, and cooperate with other protein modifications. Among them, adenosine 5'-monophosphate-activated protein kinase (AMPK), serine/threonine kinase (AKT), and nuclear factor kappa-B (NF-kB) are considered the core mechanisms in steatotic liver disease. As to treatment, lifestyle changes, prescription drugs, and herbal ingredients can alleviate symptoms by influencing phosphorylation. It demonstrates the significant role of phosphorylation as a mechanism occurrence and a therapeutic target in steatotic liver disease, which could be a new star for future exploration.

Sodium Butyrate Alleviates Free Fatty Acid-Induced Steatosis in Primary Chicken Hepatocytes via Regulating the ROS/GPX4/Ferroptosis Pathway

Fatty liver hemorrhagic syndrome (FLHS) in laying hens is a nutritional metabolic disease commonly observed in high-yielding laying hens. Sodium butyrate (NaB) and ferroptosis were reported to contribute to the pathogenesis of fatty liver-related diseases. However, the underlying mechanism of NaB in FLHS and whether it mediates ferroptosis remains unclear. A chicken primary hepatocyte induced by free fatty acids (FFAs, keeping the ratio of sodium oleate and sodium palmitate concentrations at 2:1) was established, which received treatments with NaB, the ferroptosis inducer RAS-selective lethal 3 (RSL3), and the inhibitor ferrostatin-1 (Fer-1). As a result, NaB increased biochemical and lipid metabolism indices, and the antioxidant level, while inhibiting intracellular ROS accumulation and the activation of the ferroptosis signaling pathway, as evidenced by a reduction in intracellular iron concentration, upregulated GPX4 and xCT expression, and inhibited NCOA4 and ACSL4 expression. Furthermore, treatment with Fer-1 reinforced the protective effects of NaB, while RSL3 reversed it by blocking the ROS/GPX4/ferroptosis pathway, leading to the accumulation of lipid droplets and oxidative stress. Collectively, our findings demonstrated that NaB protects hepatocytes by regulating the ROS/GPX4-mediated ferroptosis pathway, providing a new strategy and target for the treatment of FLHS.

Impact of gut microbiota on nonalcoholic fatty liver disease: insights from a leave-one-out cross-validation study

Introduction

Enteric dysbacteriosis is strongly associated with nonalcoholic fatty liver disease (NAFLD). However, the underlying causal relationship remains unknown. Thus, the present study aimed to investigate the relationship between gut microbiota and NAFLD using Mendelian randomization (MR) and analyze the target genes potentially regulated by specific microbiota.

Methods

Bidirectional two-sample MR analysis was performed using inverse variance weighted (IVW) supplemented by MR-Egger, weighted median, simple mode, and weighted mode methods. Data were pooled from gut microbiota and NAFLD association studies. The least absolute shrinkage, selection operator regression, and the Support Vector Machine algorithm were used to identify genes regulated by these intestinal flora in NAFLD. The liver expression of these genes was verified in methionine choline-deficient (MCD) diet-fed mice.

Results

IVW results confirmed a causal relationship between eight specific gut microbes and NAFLD. Notably, the order Actinomycetales, NB1n, the family Actinomycetaceae, Oxalobacteraceae and the genus Ruminococcaceae UCG005 were positively correlated, whereas Lactobacillaceae, the Christensenellaceae R7 group, and Intestinibacter were negatively correlated with NAFLD onset. In NAFLD, these eight bacteria regulated four genes: colony-stimulating factor 2 receptor β, fucosyltransferase 2, 17-beta-hydroxysteroid dehydrogenase 14, and microtubule affinity regulatory kinase 3 (MAPK3). All genes, except MARK3, were differentially expressed in the liver tissues of MCD diet-fed mice.

Discussion

The abundance of eight gut microbiota species and NAFLD progression displayed a causal relationship based on the expression of the four target genes. Our findings contributed to the advancement of intestinal microecology-based diagnostic technologies and targeted therapies for NAFLD.

Gut microbiota promotes macrophage M1 polarization in hepatic sinusoidal obstruction syndrome via regulating intestinal barrier function mediated by butyrate

BACKGROUND

The intestinal-liver axis is associated with various liver diseases. Here, we verified the role of the gut microbiota and macrophage activation in the progression of pyrrolizidine alkaloids-induced hepatic sinusoidal obstruction syndrome (PA-HSOS), and explored the possible mechanisms and new treatment options.

METHODS

The HSOS murine model was induced by gavage of monocrotaline (MCT). An analysis of 16S ribosomal DNA (16S rDNA) of the feces was conducted to determine the composition of the fecal microbiota. Macrophage clearance, fecal microbiota transplantation (FMT), and butyrate supplementation experiments were used to assess the role of intestinal flora, gut barrier, and macrophage activation and to explore the relationships among these three variables.

RESULTS

Activated macrophages and low microflora diversity were observed in HSOS patients and murine models. Depletion of macrophages attenuated inflammatory reactions and apoptosis in the mouse liver. Moreover, compared with control-FMT mice, the exacerbation of severe liver injury was detected in HSOS-FMT mice. Specifically, butyrate fecal concentrations were significantly reduced in HSOS mice, and administration of butyrate could partially alleviated liver damage and improved the intestinal barrier in vitro and in vivo. Furthermore, elevated lipopolysaccharides in the portal vein and high proportions of M1 macrophages in the liver were also detected in HSOS-FMT mice and mice without butyrate treatment, which resulted in severe inflammatory responses and further accelerated HSOS progression.

CONCLUSIONS

These results suggested that the gut microbiota exacerbated HSOS progression by regulating macrophage M1 polarization via altered intestinal barrier function mediated by butyrate. Our study has identified new strategies for the clinical treatment of HSOS.

Chitobiose exhibited a lipid-lowering effect in ob/ob-/- mice via butyric acid enrolled liver-gut crosstalk

Chitobiose (COS2) efficiently lowers lipids in vivo and facilitates butyric acid enrichment during human fecal fermentation. However, whether COS2 can interact with butyric acid to generate a hypolipidemic effect remains unclear. This study examined the hypolipidemic mechanism of COS2 involving butyric acid, which could alleviate non-alcoholic fatty liver disease (NAFLD). The results revealed that COS2 administration modulated the β-oxidation pathway in the liver and restructured the short chain fatty acids in the fecal of ob/ob-/- mice. Moreover, the hypolipidemic effect of COS2 and its specific accumulated metabolite butyric acid was verified in sodium oleate-induced HepG2 cells. Butyric acid was more effective to reverse lipid accumulation and up-regulate β-oxidation pathway at lower concentrations. Furthermore, structural analysis suggested that butyric acid formed hydrogen bonds with key residues in hydrophilic ligand binding domains (LBDs) of PPARα and activated the transcriptional activity of the receptor. Therefore, the potential mechanism behind the lipid-lowering effect of COS2 in vivo involved restoring hepatic lipid disorders via butyric acid accumulation and liver-gut axis signaling.

Differential effects of plant-based flours on metabolic homeostasis and the gut microbiota in high-fat fed rats

BACKGROUND

The gut microbiome is a salient contributor to the development of obesity, and diet is the greatest modifier of the gut microbiome, which highlights the need to better understand how specific diets alter the gut microbiota to impact metabolic disease. Increased dietary fiber intake shifts the gut microbiome and improves energy and glucose homeostasis. Dietary fibers are found in various plant-based flours which vary in fiber composition. However, the comparative efficacy of specific plant-based flours to improve energy homeostasis and the mechanism by which this occurs is not well characterized.

METHODS

In experiment 1, obese rats were fed a high fat diet (HFD) supplemented with four different plant-based flours for 12 weeks. Barley flour (BF), oat bran (OB), wheat bran (WB), and Hi-maize amylose (HMA) were incorporated into the HFD at 5% or 10% total fiber content and were compared to a HFD control. For experiment 2, lean, chow-fed rats were switched to HFD supplemented with 10% WB or BF to determine the preventative efficacy of flour supplementation.

RESULTS

In experiment 1, 10% BF and 10% WB reduced body weight and adiposity gain and increased cecal butyrate. Gut microbiota analysis of WB and BF treated rats revealed increases in relative abundance of SCFA-producing bacteria. 10% WB and BF were also efficacious in preventing HFD-induced obesity; 10% WB and BF decreased body weight and adiposity, improved glucose tolerance, and reduced inflammatory markers and lipogenic enzyme expression in liver and adipose tissue. These effects were accompanied by alterations in the gut microbiota including increased relative abundance of Lactobacillus and LachnospiraceaeUCG001, along with increased portal taurodeoxycholic acid (TDCA) in 10% WB and BF rats compared to HFD rats.

CONCLUSIONS

Therapeutic and preventative supplementation with 10%, but not 5%, WB or BF improves metabolic homeostasis, which is possibly due to gut microbiome-induced alterations. Specifically, these effects are proposed to be due to increased concentrations of intestinal butyrate and circulating TDCA.

The Role of Gut Microbiome-Derived Short-Chain Fatty Acid Butyrate in Hepatobiliary Diseases

The short-chain fatty acid butyrate, produced from fermentable carbohydrates by gut microbiota in the colon, has multiple beneficial effects on human health. At the intestinal level, butyrate regulates metabolism, helps in the transepithelial transport of fluids, inhibits inflammation, and induces the epithelial defense barrier. The liver receives a large amount of short-chain fatty acids via the blood flowing from the gut via the portal vein. Butyrate helps prevent nonalcoholic fatty liver disease, nonalcoholic steatohepatitis, inflammation, cancer, and liver injuries. It ameliorates metabolic diseases, including insulin resistance and obesity, and plays a direct role in preventing fatty liver diseases. Butyrate has different mechanisms of action, including strong regulatory effects on the expression of many genes by inhibiting the histone deacetylases and modulating cellular metabolism. The present review highlights the wide range of beneficial therapeutic and unfavorable adverse effects of butyrate, with a high potential for clinically important uses in several liver diseases.

The emerging role of miRNA-122 in infectious diseases: Mechanisms and potential biomarkers

microRNAs (miRNAs) are small, non-coding RNA molecules that play crucial regulatory roles in numerous cellular processes. Recent investigations have highlighted the significant involvement of miRNA-122 (miR-122) in the pathogenesis of infectious diseases caused by diverse pathogens, encompassing viral, bacterial, and parasitic infections. In the context of viral infections, miR-122 exerts regulatory control over viral replication by binding to the viral genome and modulating the host's antiviral response. For instance, in hepatitis B virus (HBV) infection, miR-122 restricts viral replication, while HBV, in turn, suppresses miR-122 expression. Conversely, miR-122 interacts with the hepatitis C virus (HCV) genome, facilitating viral replication. Regarding bacterial infections, miR-122 has been found to regulate host immune responses by influencing inflammatory cytokine production and phagocytosis. In Vibrio anguillarum infections, there is a significant reduction in miR-122 expression, contributing to the pathophysiology of bacterial infections. Toll-like receptor 14 (TLR14) has been identified as a novel target gene of miR-122, affecting inflammatory and immune responses. In the context of parasitic infections, miR-122 plays a crucial role in regulating host lipid metabolism and immune responses. For example, during Leishmania infection, miR-122-containing extracellular vesicles from liver cells are unable to enter infected macrophages, leading to a suppression of the inflammatory response. Furthermore, miR-122 exhibits promise as a potential biomarker for various infectious diseases. Its expression level in body fluids, particularly in serum and plasma, correlates with disease severity and treatment response in patients affected by HCV, HBV, and tuberculosis. This paper also discusses the potential of miR-122 as a biomarker in infectious diseases. In summary, this review provides a comprehensive and insightful overview of the emerging role of miR-122 in infectious diseases, detailing its mechanism of action and potential implications for the development of novel therapeutic strategies.

Short-chain fatty acids in diseases

Short-chain fatty acids (SCFAs) are the main metabolites produced by bacterial fermentation of dietary fibre in the gastrointestinal tract. The absorption of SCFAs is mediated by substrate transporters, such as monocarboxylate transporter 1 and sodium-coupled monocarboxylate transporter 1, which promote cellular metabolism. An increasing number of studies have implicated metabolites produced by microorganisms as crucial executors of diet-based microbial influence on the host. SCFAs are important fuels for intestinal epithelial cells (IECs) and represent a major carbon flux from the diet, that is decomposed by the gut microbiota. SCFAs play a vital role in multiple molecular biological processes, such as promoting the secretion of glucagon-like peptide-1 by IECs to inhibit the elevation of blood glucose, increasing the expression of G protein-coupled receptors such as GPR41 and GPR43, and inhibiting histone deacetylases, which participate in the regulation of the proliferation, differentiation, and function of IECs. SCFAs affect intestinal motility, barrier function, and host metabolism. Furthermore, SCFAs play important regulatory roles in local, intermediate, and peripheral metabolisms. Acetate, propionate, and butyrate are the major SCFAs, they are involved in the regulation of immunity, apoptosis, inflammation, and lipid metabolism. Herein, we review the diverse functional roles of this major class of bacterial metabolites and reflect on their ability to affect intestine, metabolic, and other diseases. Video Abstract.

Low abundance of insulin-induced gene 1 contributes to SREBP-1c processing and hepatic steatosis in dairy cows with severe fatty liver

Fatty liver is a major metabolic disorder of high-producing dairy cows during the transition period. In nonruminants, it is well established that insulin-induced gene 1 (INSIG1) plays a crucial role in regulating hepatic lipogenesis by controlling the anchoring of sterol regulatory element-binding protein 1 (SREBP-1) on the endoplasmic reticulum along with SREBP cleavage-activating protein (SCAP). Whether the INSIG1-SCAP-SREBP-1c transport axis is affected in cows experiencing fatty liver is unknown. Thus, the aim of this study was to investigate the potential role of INSIG1-SCAP-SREBP-1c axis in the progression of fatty liver in dairy cows. For in vivo experiments, 24 dairy cows at the start of their fourth lactation (median; range 3-5) and 8 d in milk (median; range 4-12 d) were selected into a healthy group [n = 12; triglyceride (TG) content <1%] and a severe fatty liver group (n = 12; TG content >10%) according to their hepatic TG content. Blood samples were collected for detecting serum concentrations of free fatty acids, β-hydroxybutyrate, and glucose. Compared with healthy cows, cows with severe fatty liver had higher serum concentrations of β-hydroxybutyrate and free fatty acids and lower concentration of glucose. Liver biopsies were used to detect the status of INSIG1-SCAP-SREBP-1c axis, and the mRNA expression of SREBP-1c-target lipogenic genes acetyl-CoA carboxylase α (ACACA), fatty acid synthase (FASN), and diacylglycerol acyltransferase 1 (DGAT1). Cows with severe fatty liver had lower protein expression of INSIG1 in the hepatocyte endoplasmic reticulum fraction, greater protein expression of SCAP and precursor SREBP-1c in the hepatocyte Golgi fraction, and greater protein expression of mature SREBP-1c in the hepatocyte nuclear fraction. In addition, the mRNA expression of SREBP-1c-target lipogenic genes ACACA, FASN, and DGAT1 was greater in the liver of dairy cows with severe fatty liver. In vitro experiments were conducted on hepatocytes isolated from 5 healthy 1-d-old female Holstein calves, and hepatocytes from each calf were run independently. First, hepatocytes were treated with 0, 200, or 400 μM palmitic acid (PA) for 12 h. Exogenous PA treatment decreased INSIG1 protein abundance, enhanced the endoplasmic reticulum to Golgi export of SCAP-precursor SREBP-1c complex and the nuclear translocation of mature SREBP-1c, all of which was associated with increased transcriptional activation of lipogenic genes and TG synthesis. Second, hepatocytes were transfected with INSIG1-overexpressing adenovirus for 48 h and treated with 400 μM PA 12 h before the end of transfection. Overexpressing INSIG1 inhibited PA-induced SREBP-1c processing, upregulation of lipogenic genes, and TG synthesis in hepatocytes. Overall, the present in vivo and in vitro results indicated that the low abundance of INSIG1 contributed to SREBP-1c processing and hepatic steatosis in dairy cows. Thus, the INSIG1-SCAP-SREBP-1c axis may be a novel target for treatment of fatty liver in dairy cows.

Policosanol Stimulates Osteoblast Differentiation via Adenosine Monophosphate-Activated Protein Kinase-Mediated Expression of Insulin-Induced Genes 1 and 2

Policosanol is known as a hypocholesterolemic compound and is derived from plants such as sugar cane and corn. Policosanol can lower blood pressure or inhibit adipogenesis, but its effect on osteogenic differentiation and the molecular mechanism is unclear. This study aims to investigate the effect of policosanol on osteogenic differentiation in MC3T3-E1 cells and zebrafish models. Administration of policosanol into MC3T3-E1 induced the expression of the osteogenic genes such as distal-less homeobox 5 (Dlx5) and runt-related transcription factor 2 (Runx2). Alkaline phosphatase activity and extracellular mineralization also increased. Policosanol promoted activation of adenosine monophosphate-activated protein kinase (AMPK) and insulin-induced genes (INSIGs) expression and regulation of INSIGs modulated osteoblast differentiation. AMPK activation through transfection of the constitutively active form of AMPK (CA-AMPK) increased INSIGs expression, whereas policosanol-induced INSIGs expression was suppressed by inhibitor of AMPK (Com. C). Furthermore, the osteogenic effects of policosanol were verified in zebrafish. Amputated caudal fin rays were regenerated by policosanol treatment. Taken together, these results show that policosanol increases osteogenic differentiation and contributes to fin regeneration in zebrafish via AMPK-mediated INSIGs expression, suggesting that policosanol has potential as an osteogenic agent.

Vitamin D/vitamin D receptor pathway in non-alcoholic fatty liver disease

INTRODUCTION

Non-alcoholic fatty liver disease (NAFLD) is the most common cause of chronic liver disease worldwide, but underlying mechanisms are not fully understood. In recent years, a growing body of evidence has emphasized the therapeutic role of vitamin D in NAFLD, but the specific mechanism remains to be investigated.

AREAS COVERED

This review summarized the roles of vitamin D/VDR (vitamin D receptor) pathway in different types of liver cells (such as hepatocytes, hepatic stellate cells, liver macrophages, T lymphocytes, and other hepatic immune cells) in case of NAFLD. Meanwhile, the effects of pathways in the gut-liver axis, adipose tissue-liver axis, and skeletal muscle-liver axis on the development of NAFLD were further reviewed. Relevant literature was searched on PubMed for the writing of this review.

EXPERT OPINION

The precise regulation of regional vitamin D/VDR signaling pathway based on cell-specific or tissue-specific function will help clarify the potential mechanism of vitamin D in NAFLD, which may provide new therapeutic targets to improve the safety and efficacy of vitamin D based drugs.

Limited role for hyperammonemia in the progression of diet-induced nonalcoholic steatohepatitis

OBJECTIVES

To determine whether hyperammonemia has a direct impact on steatohepatitis in mice fed with a high-fat diet (HFD).

METHODS

Male C57BL/6 mice were divided into two groups receiving either chow diet or HFD. After 12-week NASH modeling, hyperammonemia was induced by intragastric administration of ammonium chloride solution (NH4 Cl) or liver-specific carbamoyl phosphate synthetase 1 (Cps1) knockdown. In vitro experiments were performed in HepG2 cells induced by free fatty acid (FFA) and NH4 Cl.

RESULTS

NH4 Cl administration led to increased levels of plasma and hepatic ammonia in NASH mice. NH4 Cl-induced hyperammonemia did not influence liver histological changes in mice fed with HFD; however, elevated plasma cholesterol level, and an increasing trend of liver lipid content were observed. No significant effect of hyperammonemia on hepatic inflammation and fibrosis in NASH mice was found. In vitro cell experiments showed that NH4 Cl treatment failed to increase the lipid droplet content and the expressions of de novo lipogenesis genes in HepG2 cells induced by FFA. The knockdown of Cps1 in HFD-fed mice resulted in elevated plasma ammonia levels but did not cause histological change in the liver.

CONCLUSIONS

Our study revealed a limited role of ammonia in aggravating the progression of NASH. Further studies are needed to clarify the role and mechanism of ammonia in NASH development.

Short-Chain Fatty-Acid-Producing Bacteria: Key Components of the Human Gut Microbiota

Short-chain fatty acids (SCFAs) play a key role in health and disease, as they regulate gut homeostasis and their deficiency is involved in the pathogenesis of several disorders, including inflammatory bowel diseases, colorectal cancer, and cardiometabolic disorders. SCFAs are metabolites of specific bacterial taxa of the human gut microbiota, and their production is influenced by specific foods or food supplements, mainly prebiotics, by the direct fostering of these taxa. This Review provides an overview of SCFAs' roles and functions, and of SCFA-producing bacteria, from their microbiological characteristics and taxonomy to the biochemical process that lead to the release of SCFAs. Moreover, we will describe the potential therapeutic approaches to boost the levels of SCFAs in the human gut and treat different related diseases.

Ampicillin exacerbates acetaminophen-induced acute liver injury by inducing intestinal microbiota imbalance and butyrate reduction

BACKGROUND AND AIMS

Antibiotics (ATBx) and acetaminophen (APAP) are widely used worldwide. APAP is the most common cause of acute liver injury (ALI) and might be used in combination with ATBx in clinics. However, the impact of ATBx on APAP-induced ALI has rarely been studied.

METHODS

First, we compared the effects of seven ATBx on APAP-induced ALI. Then, we analysed faecal, serum and liver samples to investigate the impact of the gut microbiota on this process. Finally, we assessed the role of short-chain fatty acids in this process.

RESULTS

In this work, we found that the ALI was significantly aggravated in the mice treated with ampicillin (Amp) instead of other ATBx. Amp exposure reduced the diversity and altered the composition of gut microbiota. The altered gut microbiota aggravated APAP-induced ALF, which was proven by faecal microbiota transplantation from ATBx-treated mice. Metagenomic analysis showed a significantly decreased Lactobacillus abundance in Amp-treated mice. Gavage with Lactobacillus, especially Lactobacillus rhamnosus, significantly reversed the severer ALF induced by APAP and Amp. Moreover, Lactobacillus supplementation increased butyrate-producing clostridia and lowered butyrate levels in Amp-treated mice. In accordance, butyrate supplementation could also alleviate Amp-aggravated ALI. In addition, inhibition of nuclear factor erythroid 2-related factor 2 counteracted the protective effect of butyrate on aggravated ALI induced by Amp and APAP.

CONCLUSION

Together, this study revealed a potential health impact of Amp that may exacerbate liver damage when co-exposed to excess APAP.

The effect of G0S2 on insulin sensitivity: A proteomic analysis in a G0S2-overexpressed high-fat diet mouse model

BACKGROUND

Previous research has shown a tight relationship between the G0/G1 switch gene 2 (G0S2) and metabolic diseases such as non-alcoholic fatty liver disease (NAFLD) and obesity and diabetes, and insulin resistance has been shown as the major risk factor for both NAFLD and T2DM. However, the mechanisms underlying the relationship between G0S2 and insulin resistance remain incompletely understood. Our study aimed to confirm the effect of G0S2 on insulin resistance, and determine whether the insulin resistance in mice fed a high-fat diet (HFD) results from G0S2 elevation.

METHODS

In this study, we extracted livers from mice that consumed HFD and received tail vein injections of AD-G0S2/Ad-LacZ, and performed a proteomics analysis.

RESULTS

Proteomic analysis revealed that there was a total of 125 differentially expressed proteins (DEPs) (56 increased and 69 decreased proteins) among the identified 3583 proteins. Functional enrichment analysis revealed that four insulin signaling pathway-associated proteins were significantly upregulated and five insulin signaling pathway -associated proteins were significantly downregulated.

CONCLUSION

These findings show that the DEPs, which were associated with insulin resistance, are generally consistent with enhanced insulin resistance in G0S2 overexpression mice. Collectively, this study demonstrates that G0S2 may be a potential target gene for the treatment of obesity, NAFLD, and diabetes.

Faecalibacterium prausnitzii prevents hepatic damage in a mouse model of NASH induced by a high-fructose high-fat diet

Introduction

Nonalcoholic steatohepatitis (NASH) is an advanced nonalcoholic fatty liver disease characterized by chronic inflammation and fibrosis. A dysbiosis of the gut microbiota has been associated with the pathophysiology of NASH, and probiotics have proven helpful in its treatment and prevention. Although both traditional and next-generation probiotics have the potential to alleviate various diseases, studies that observe the therapeutic effect of next-generation probiotics on NASH are lacking. Therefore, we investigated whether a next-generation probiotic candidate, Faecalibacterium prausnitzii, contributed to the mitigation of NASH.

Methods

In this study, we conducted 16S rRNA sequencing analyses in patients with NASH and healthy controls. To test F. prausnitzii could alleviate NASH symptoms, we isolated four F. prausnitzii strains (EB-FPDK3, EB-FPDK9, EB-FPDK11, and EB-FPYYK1) from fecal samples collected from four healthy individuals. Mice were maintained on a high-fructose high-fat diet for 16 weeks to induce a NASH model and received oral administration of the bacterial strains. Changes in characteristic NASH phenotypes were assessed via oral glucose tolerance tests, biochemical assays, and histological analyses.

Results

16S rRNA sequencing analyses confirmed that the relative abundance of F. prausnitzii reduced significantly in patients with NASH compared to healthy controls (p &lt; 0.05). In the NASH mice, F. prausnitzii supplementation improved glucose homeostasis, prevented hepatic lipid accumulation, curbed liver damage and fibrosis, restored damaged gut barrier functions, and alleviated hepatic steatosis and liver inflammation. Furthermore, real-time PCR assays documented that the four F. prausnitzii strains regulated the expression of genes related to hepatic steatosis in these mice.

Discussion

Our study, therefore, confirms that the administration of F. prausnitzii bacteria can alleviate NASH symptoms. We propose that F. prausnitzii has the potential to contribute to the next-generation probiotic treatment of NASH.

The gut microbiota: A new perspective for tertiary prevention of hepatobiliary and gallbladder diseases

The gut microbiota is a complex ecosystem that has coevolved with the human body for hundreds of millions of years. In the past 30 years, with the progress of gene sequencing and omics technology, the research related to gut microbiota has developed rapidly especially in the field of digestive system diseases and systemic metabolic diseases. Mechanical, biological, immune, and other factors make the intestinal flora form a close bidirectional connection with the liver and gallbladder, which can be called the "gut-liver-biliary axis." Liver and gallbladder, as internal organs of the peritoneum, suffer from insidious onset, which are not easy to detect. The diagnosis is often made through laboratory chemical tests and imaging methods, and intervention measures are usually taken only when organic lesions have occurred. At this time, some people may have entered the irreversible stage of disease development. We reviewed the literature describing the role of intestinal flora in the pathogenesis and biotherapy of hepatobiliary diseases in the past 3-5 years, including the dynamic changes of intestinal flora at different stages of the disease, as well as the signaling pathways involved in intestinal flora and its metabolites, etc. After summarizing the above contents, we hope to highlight the potential of intestinal flora as a new clinical target for early prevention, early diagnosis, timely treatment and prognosis of hepatobiliary diseases. GRAPHICAL ABSTRACT.

Elevated serum levels of diamine oxidase, D-lactate and lipopolysaccharides are associated with metabolic-associated fatty liver disease

BACKGROUND

Studies have suggested an association between metabolic-associated fatty liver disease (MAFLD) and intestinal barrier function. The present study aims to investigate the association between MAFLD and intestinal barrier impairment in humans and identify potential risk factors for MAFLD.

METHODS

A total of 491 patients were retrospectively enrolled in this study. The serum levels of diamine oxidase, D-lactate and lipopolysaccharide were measured to evaluate intestinal barrier integrity in patients with and without MAFLD. Binary logistic regression and correlational analyses were conducted to verify the association between MAFLD and serum levels of intestinal barrier biomarkers.

RESULTS

We enrolled 294 patients with MAFLD and 197 patients without MAFLD in this study. Patients with MAFLD had higher serum levels of diamine oxidase, D-lactate and lipopolysaccharide (P < 0.001) than those without MAFLD. Multivariate logistic regression analyses showed that BMI [odds ratio (OR) 1.324; P < 0.001], triglycerides (OR 2.649; P = 0.002), nonesterified fatty acids (OR 1.002; P = 0.011), diamine oxidase (OR 1.149; P = 0.011) and D-lactate (OR 1.221; P < 0.001) were independent risk factors for MAFLD. Additionally, serum levels of diamine oxidase and D-lactate increase as liver steatosis became more severe. MAFLD patients with ≥2 metabolic abnormalities had higher serum levels of lipopolysaccharide (P = 0.034).

CONCLUSIONS

MAFLD is associated with intestinal barrier impairment. Diamine oxidase and D-lactate are potential predictors of MAFLD, and their serum levels are related to liver steatosis. Intestinal barrier impairment is related to metabolic disorders in patients with MAFLD.

Gut microbiota-derived short-chain fatty acids regulate gastrointestinal tumor immunity: a novel therapeutic strategy?

Tumor immune microenvironment (TIME), a tumor-derived immune component, is proven to be closely related to the development, metastasis, and recurrence of tumors. Gut microbiota and its fermented-metabolites short-chain fatty acids (SCFAs) play a critical role in maintaining the immune homeostasis of gastrointestinal tumors. Consisting mainly of acetate, propionate, and butyrate, SCFAs can interact with G protein-coupled receptors 43 of T helper 1 cell or restrain histone deacetylases (HDACs) of cytotoxic T lymphocytes to exert immunotherapy effects. Studies have shed light on SCFAs can mediate the differentiation and function of regulatory T cells, as well as cytokine production in TIME. Additionally, SCFAs can alter epigenetic modification of CD8⁺ T cells by inhibiting HDACs to participate in the immune response process. In gastrointestinal tumors, the abundance of SCFAs and their producing bacteria is significantly reduced. Direct supplementation of dietary fiber and probiotics, or fecal microbiota transplantation to change the structure of gut microbiota can both increase the level of SCFAs and inhibit tumor development. The mechanism by which SCFAs modulate the progression of gastrointestinal tumors has been elucidated in this review, aiming to provide prospects for the development of novel immunotherapeutic strategies.

Interaction between the PNPLA3 Gene and Nutritional Factors on NAFLD Development: The Korean Genome and Epidemiology Study

Genetic and nutritional factors contribute to the development of non-alcoholic fatty liver disease (NAFLD); however, gene-diet interactions in NAFLD development are poorly understood. In this case-control study, a large dataset from the Korean Genome and Epidemiology Study cohort (n = 72,299) comprising genomic data, medical records, social history, and dietary data was used. We investigated the interactions between the PNPLA3 rs738409 genotype and nutritional factors and their possible effect on the risk of NAFLD development in 2950 patients with NAFLD and 12,907 controls. In the PNPLA3 risk allele group, high protein, fat, sodium, phosphorus, niacin, and vitamin B6 intakes were associated with a decreased risk of NAFLD. In the non-risk allele group, only high fat intake was associated with a decreased risk of NAFLD. Among these nutrients, high sodium intake had a significant protective interaction with the PNPLA3 genotype against NAFLD (p = 0.002). Among salty foods, only kimchi had a significant protective effect against the PNPLA3 genotype (p = 0.012). Thus, the PNPLA3 genotype is differentially associated with nutritional factors. In particular, it interacts with kimchi, a fermented vegetable dish. Therefore, fermented vegetables may serve as a tailored therapeutic food for people with the PNPLA3 risk allele.

Recent advances and potentiality of postbiotics in the food industry: Composition, inactivation methods, current applications in metabolic syndrome, and future trends

Postbiotics are defined as "preparation of inanimate microorganisms and/or their components that confers a health benefit on the host". Postbiotics have unique advantages over probiotics, such as stability, safety, and wide application. Although postbiotics are research hotspots, the research on them is still very limited. This review provides comprehensive information on the scope of postbiotics, the preparation methods of inanimate microorganisms, and the application and mechanisms of postbiotics in metabolic syndrome (MetS). Furthermore, the application trends of postbiotics in the food industry are reviewed. It was found that postbiotics mainly include inactivated microorganisms, microbial lysates, cell components, and metabolites. Thermal treatments are the main methods to prepare inanimate microorganisms as postbiotics, while non-thermal treatments, such as ionizing radiation, ultraviolet light, ultrasound, and supercritical CO2, show great potential in postbiotic preparation. Postbiotics could ameliorate MetS through multiple pathways including the modulation of gut microbiota, the enhancement of intestinal barrier, the regulation of inflammation and immunity, and the modulation of hormone homeostasis. Additionally, postbiotics have great potential in the food industry as functional food supplements, food quality improvers, and food preservatives. In addition, the SWOT analyses showed that the development of postbiotics in the food industry exists both opportunities and challenges.

AUF-1 knockdown in mice undermines gut microbial butyrate-driven hypocholesterolemia through AUF-1-Dicer-1-mir-122 hierarchy

Introduction and objective

Cholesterol homeostasis is a culmination of cellular synthesis, efflux, and catabolism to important physiological entities where short chain fatty acid, butyrate embodied as a key player. This discourse probes the mechanistic molecular details of butyrate action in maintaining host-cholesterol balance.

Methods

Hepatic mir-122 being the most indispensable regulator of cholesterol metabolic enzymes, we studied upstream players of mir-122 biogenesis in the presence and absence of butyrate in Huh7 cells and mice model. We synthesized unique self-transfecting GMO (guanidinium-morpholino-oligo) linked PMO (Phosphorodiamidate-Morpholino Oligo)-based antisense cell-penetrating reagent to selectively knock down the key player in butyrate mediated cholesterol regulation.

Results

We showed that butyrate treatment caused upregulation of RNA-binding protein, AUF1 resulting in RNase-III nuclease, Dicer1 instability, and significant diminution of mir-122. We proved the importance of AUF1 and sequential downstream players in AUF1-knock-down mice. Injection of GMO-PMO of AUF1 in mouse caused near absence of AUF1 coupled with increased Dicer1 and mir-122, and reduced serum cholesterol regardless of butyrate treatment indicating that butyrate acts through AUF1.

Conclusion

The roster of intracellular players was as follows: AUF1-Dicer1-mir-122 for triggering butyrate driven hypocholesterolemia. To our knowledge this is the first report linking AUF-1 with cholesterol biogenesis.

Interventions for non-alcoholic liver disease: a gut microbial metabolites perspective

Over the past two decades, non-alcoholic fatty liver disease (NAFLD) has become a leading burden of hepatocellular carcinoma and liver transplantation. Although the exact pathogenesis of NAFLD has not been fully elucidated, recent hypotheses placed more emphasis on the crucial role of the gut microbiome and its derivatives. Reportedly, microbial metabolites such as short-chain fatty acids, amino acid metabolites (indole and its derivatives), bile acids (BAs), trimethylamine N-oxide (TMAO), and endogenous ethanol exhibit sophisticated bioactive properties. These molecules regulate host lipid, glucose, and BAs metabolic homeostasis via modulating nutrient absorption, energy expenditure, inflammation, and the neuroendocrine axis. Consequently, a broad range of research has studied the therapeutic effects of microbiota-derived metabolites. In this review, we explore the interaction of microbial products and NAFLD. We also discuss the regulatory role of existing NAFLD therapies on metabolite levels and investigate the potential of targeting those metabolites to relieve NAFLD.

Mechanistic insights into the pleiotropic effects of butyrate as a potential therapeutic agent on NAFLD management: A systematic review

Non-alcoholic fatty liver disease (NAFLD) is one of the most common chronic diseases worldwide. As a multifaceted disease, NAFLD's pathogenesis is not entirely understood, but recent evidence reveals that gut microbiota plays a significant role in its progression. Butyrate, a gut microbiota metabolite, has been reported to have hepato-protective effects in NAFLD animal models. The purpose of this systematic review is to determine how butyrate affects the risk factors for NAFLD. Searches were conducted using relevant keywords in electronic databases up to March 2022. According to the evidence presented in this study, butyrate contributes to a wide variety of biological processes in the gut-liver axis. Its beneficial properties include improving intestinal homeostasis and liver health as well as anti-inflammatory, metabolism regulatory and anti-oxidative effects. These effects may be attributed to butyrate's ability to regulate gene expression as an epigenetic modulator and trigger cellular responses as a signalling molecule. However, the exact underlying mechanisms remain unclear. Human trials have not been performed on the effect of butyrate on NAFLD, so there are concerns about whether the results of animal studies can be translated to humans. This review summarises the current knowledge about the properties of butyrate, particularly its potential effects and mechanisms on liver health and NAFLD management.

The gut microbiota and endometriosis: From pathogenesis to diagnosis and treatment

Endometriosis is a common gynecological disease, that often leads to pain and infertility. At present, the specific pathogenesis of endometriosis has not been clarified, but it may be closely related to an imbalance of sex hormones in the body, ectopic hyperplasia stimulated by immune inflammation, and invasion and escape based on tumor characteristics. Gut microbiota is associated with many inflammatory diseases. With the further study of the gut microbiota, people are paying increasing attention to its relationship with endometriosis. Studies have shown that there is an association between the gut microbiota and endometriosis. The specific ways and mechanisms by which the gut microbiota participates in endometriosis may involve estrogen, immune inflammation, and tumor characteristics, among others. Therefore, in the future, regulating gut microbiota disorders in various ways can help in the treatment of endometriosis patients. This study reviewed the research on the gut microbiota and endometriosis in order to provide ideas for clinical diagnosis and treatment.

Effects of Maternal Gut Microbiota-Targeted Therapy on the Programming of Nonalcoholic Fatty Liver Disease in Dams and Fetuses, Related to a Prenatal High-Fat Diet

Metabolic disorders can start in utero. Maternal transmission of metabolic phenotypes may increase the risks of adverse metabolic outcomes, such as nonalcoholic fatty liver disease (NAFLD); effective intervention is essential to prevent this. The gut microbiome plays a crucial role in fat storage, energy metabolism, and NAFLD. We investigated the therapeutic use of probiotic Lactobacillus reuteri and postbiotic butyrate gestation in the prevention of perinatal high-fat diet-induced programmed hepatic steatosis in the offspring of pregnant Sprague–Dawley rats who received regular chow or a high-fat (HF) diet 8 weeks before mating. L. reuteri or sodium butyrate was administered via oral gavage to the gestated rats until their sacrifice on day 21 of gestation. Both treatments improved liver steatosis in pregnant dams; L. reuteri had a superior effect. L. reuteri ameliorated obesity and altered the metabolic profiles of obese gravid dams. Maternal L. reuteri therapy prevented maternal HF diet-induced fetal liver steatosis, and reformed placental remodeling and oxidative injury. Probiotic therapy can restore lipid dysmetabolism in the fetal liver, modulate nutrient-sensing molecules in the placenta, and mediate the short-chain fatty acid signaling cascade. The therapeutic effects of maternal L. reuteri on maternal NAFLD and NAFLD reprogramming in offspring should be validated for further clinical translation.

Association of metabolic dysfunction-associated fatty liver disease with kidney disease

Non-alcoholic fatty liver disease (NAFLD) is characterized by the accumulation of fat in more than 5% of hepatocytes in the absence of excessive alcohol consumption and other secondary causes of hepatic steatosis. In 2020, the more inclusive term metabolic (dysfunction)-associated fatty liver disease (MAFLD) - defined by broader diagnostic criteria - was proposed to replace the term NAFLD. The new terminology and revised definition better emphasize the pathogenic role of metabolic dysfunction and uses a set of definitive, inclusive criteria for diagnosis. Diagnosis of MAFLD is based on evidence of hepatic steatosis (as assessed by liver biopsy, imaging techniques or blood biomarkers and scores) in persons who are overweight or obese and have type 2 diabetes mellitus or metabolic dysregulation, regardless of the coexistence of other liver diseases or excessive alcohol consumption. The known association between NAFLD and chronic kidney disease (CKD) and our understanding that CKD can occur as a consequence of metabolic dysfunction suggests that individuals with MAFLD - who by definition have fatty liver and metabolic comorbidities - are at increased risk of CKD. In this Perspective article, we discuss the clinical associations between MAFLD and CKD, the pathophysiological mechanisms by which MAFLD may increase the risk of CKD and the potential drug treatments that may benefit both conditions.

Ammonia Scavenger Restores Liver and Muscle Injury in a Mouse Model of Non-alcoholic Steatohepatitis With Sarcopenic Obesity

Recent studies have revealed that sarcopenia is closely associated with obesity and non-alcoholic steatohepatitis (NASH). However, few attempted to explore the cause-and-effect relationship between sarcopenic obesity and NASH. In this study, we investigated muscular alterations in a rodent NASH model to elucidate their intrinsic relations and explore the potential therapeutic target. Forty-six 8-week-old and twenty 42-week-old male C57BL/6 mice (defined as young and middle-aged mice, respectively) were fed with a high-fat diet (HFD) for 12 or 20 weeks. A subset of young mice was subjected to ammonia lowering treatment by L-ornithine L-aspartate (LOLA). We examined body composition and muscle strength by nuclear magnetic resonance and grip strength meter, respectively. At the end of the 12th week, all HFD-fed mice developed typical steatohepatitis. Meanwhile, sarcopenia occurred in HFD-fed middle-aged mice, whereas young mice only demonstrated decreased grip strength. Until the end of week 20, young mice in the HFD group exhibited significant sarcopenia and obesity phenotypes, including decreased lean body mass and grip strength, and increased body fat mass and percentage body fat. Additionally, plasma ammonia level was markedly increased in HFD-fed mice of both ages at week 20. Plasma ammonia level was negatively associated with muscle strength and myofiber diameter in young mice. LOLA can significantly reduce plasma levels of ammonia, alanine aminotransaminase, aspartate aminotransaminase, and cholesterol in mice fed an HFD. Hepatic infiltration of inflammatory cells and collagen deposition area were significantly decreased in HFD group by LOLA treatment. Meanwhile, LOLA significantly increased lean body mass, grip strength, and average muscle fiber diameter of HFD-fed mice. These findings suggest that the occurrence of NASH precedes sarcopenia in HFD mice, and the steatohepatitis-related hyperammonemia might contribute to the pathogenesis of sarcopenia. LOLA might be an effective drug for both steatohepatitis and sarcopenic obesity.

Maternal obesogenic diet regulates offspring bile acid homeostasis and hepatic lipid metabolism via the gut microbiome in mice

Mice exposed in gestation to maternal high-fat/high-sucrose (HF/HS) diet develop altered bile acid (BA) homeostasis. We hypothesized that these reflect an altered microbiome and asked if microbiota transplanted from HF/HS offspring change hepatic BA and lipid metabolism to determine the directionality of effect. Female mice were fed HF/HS or chow (CON) for 6 wk and bred with lean males. 16S sequencing was performed to compare taxa in offspring. Cecal microbiome transplantation (CMT) was performed from HF/HS or CON offspring into antibiotic-treated mice fed chow or high fructose. BA, lipid metabolic, and gene expression analyses were performed in recipient mice. Gut microbiomes from HF/HS offspring segregated from CON offspring, with increased Firmicutes to Bacteriodetes ratios and Verrucomicrobial abundance. After CMT was performed, HF/HS-recipient mice had larger BA pools, increased intrahepatic muricholic acid, and decreased deoxycholic acid species. HF/HS-recipient mice exhibited downregulated hepatic Mrp2, increased hepatic Oatp1b2, and decreased ileal Asbt mRNA expression. HF/HS-recipient mice exhibited decreased cecal butyrate and increased hepatic expression of Il6. HF/HS-recipient mice had larger livers and increased intrahepatic triglyceride versus CON-recipient mice after fructose feeding, with increased hepatic mRNA expression of lipogenic genes including Srebf1, Fabp1, Mogat1, and Mogat2. CMT from HF/HS offspring increased BA pool and shifted the composition of the intrahepatic BA pool. CMT from HF/HS donor offspring increased fructose-induced liver triglyceride accumulation. These findings support a causal role for vertical transfer of an altered microbiome in hepatic BA and lipid metabolism in HF/HS offspring.NEW & NOTEWORTHY We utilized a mouse model of maternal obesogenic diet exposure to evaluate the effect on offspring microbiome and bile acid homeostasis. We identified shifts in the offspring microbiome associated with changes in cecal bile acid levels. Transfer of the microbiome from maternal obesogenic diet-exposed offspring to microbiome-depleted mice altered bile acid homeostasis and increased fructose-induced hepatic steatosis.