Escherichia fergusonii Promotes Nonobese Nonalcoholic Fatty Liver Disease by Interfering With Host Hepatic Lipid Metabolism Through Its Own msRNA 23487

Prevotella copri-produced 5-aminopentanoic acid promotes pediatric metabolic dysfunction-associated steatotic liver disease

BACKGROUND

Recent studies suggest an association between the expansion of Prevotella copri and the disease severity in children with metabolic dysfunction-associated steatotic liver disease (MASLD). We aimed to investigate the causative role and molecular mechanisms of P. copri in pediatric MASLD.

METHODS

C57BL/6 J mice aged 3 weeks were fed a high-fat diet (HFD) and orally administered with P. copri for 5 weeks. We assessed the key features of MASLD and the gut microbiota profile. By untargeted metabolomics on mouse fecal samples and the supernatant from P. copri culture, we identified P. copri-derived metabolite and tested its effects in vitro.

RESULTS

In HFD-fed mice, administration of P. copri significantly promoted liver steatosis. Genes associated with inflammation and fibrosis were significantly upregulated in the livers from the HFD + P. copri group compared with those in the livers from the HFD group. In addition, P. copri reduced gut microbial diversity, increased the proportion of Firmicutes and decreased Bacteroidota. Importantly, 5-aminopentanoic acid (5-AVA) was significantly enriched in both mouse feces from the HFD + P. copri group and the culture supernatant of P. copri. In vitro, 5-AVA aggravated palmitic acid-induced lipid accumulation in HepG2 cells and primary mouse hepatocytes. Mechanistically, P. copri-produced 5-AVA exacerbated hepatic steatosis by promoting lipogenesis and fatty acid uptake, while also reducing hepatic very-low-density lipoprotein export.

CONCLUSIONS

Our findings demonstrated that P. copri promotes liver steatosis in HFD-fed juvenile mice through its metabolite 5-AVA, suggesting its potential as a therapeutic target for the management of pediatric MASLD.

Polysaccharides from Cistanche deserticola Ma prevent alcoholic fatty liver disease by regulating hepatic lipid metabolism and gut microbiota in mice

Cistanche deserticola Ma polysaccharide (CDP) is an active ingredient extracted from Cistanche deserticola Ma (CD) and is believed to have hepatoprotective activity. However, the molecular mechanism of its hepatoprotective effect by intervening in alcoholic fatty liver disease (AFLD) remains unclear. In the present study, three polysaccharides were isolated and purified from CD, and the polysaccharide with the better lipid-lowering and liver-protecting activity and the highest yield, CDPS, was selected by in vitro experiments for subsequent. The efficacy of CDPS in ameliorating AFLD in mice was evaluated using hepatic lipidomics, 16S rRNA analysis and molecular biology experiments. The present study showed that CDPS significantly improved alcohol-induced weight loss, lipid accumulation, ALT, AST, inflammation and dyslipidemia, suggesting that CDPS can prevent AFLD. Lipidomics showed that CDPS improved lipid metabolism disorders by regulating glycerophospholipid metabolism, linoleic acid metabolism, and arachidonic acid metabolism. 16S rRNA analysis showed that CDPS ameliorated alcohol-induced gut microbiota disruption. In particular, CDPS supplementation reduced the abundance of Bacteroides, Parabacteroides, and Escherichia-Shigella and increased the abundance of Ruminococcaceae_UCG-010, Lachnospiraceae_NK4A136_group and Faecalibaculum abundance, and promoted the production of SCFAs. We further used Western blotting to determine the levels of proteins involved in lipogenesis and catabolism, and CDPS intervention resulted in decreased levels of lipid synthesis-associated proteins (SREBP-1c and FAS) and increased levels of lipid catabolism-associated proteins (PPARα) and p-AMPK/AMPK ratio. Our results suggest that CDPS has the potential to prevent AFLD by modulating lipid metabolism, altering the gut microbiota, increasing the content of SCFAs, activating the AMPK signaling pathway to promote fatty acid β-oxidation and limiting fatty acid biosynthesis, which provides a basis for further development of therapeutic drugs for AFLD.

Beyond obesity: lean metabolic dysfunction-associated steatohepatitis from unveiling molecular pathogenesis to therapeutic advancement

Nonalcoholic fatty liver disease (NAFLD), now known by the name of metabolic dysfunction-associated fatty liver disease (MAFLD), with increased global incidence, has been recognized as a significant metabolic disorder. NAFLD includes a spectrum liver disease from hepatocellular fat accumulation (isolated steatosis) to an advanced form of liver injury known as nonalcoholic steatohepatitis (NASH), which refers to distinct histologic features, including hepatocellular steatosis and injury, necroinflammation, and eventually fibrosis. Nonobese or lean individuals associated with metabolic dysregulation usually demonstrated diverse risk factors compared to obese MAFLD. The presence of normal range body mass index (BMI) and excess visceral adiposity with increased cardiometabolic and renal comorbidities, along with sarcopenia, has been evidenced to be associated with lean MASH. Genetic predispositions accompanying lifestyle and environmental factors contribute to disease initiation and progression. The genetic influence in pathophysiology indicated the significant contributions of the following genes: PNPLA3, TM6SF2, APOB, LIPA, MBOAT7, and HSD17B13, and the impact of their disease-specific variants in the development of obesity-independent MASH. The epigenetic modifications exhibited differential DNA methylation patterns in the genes involved in lipid metabolism, particularly hypomethylation of PEMT. Diet-induced and genetic animal models of lean MASH, including Slc: Wistar/ST rats, PPAR-α, PTEN, and MAT1A knockout mice models, are indicated to be pivotal in the exploration of disease progression and observing the effect of therapeutic interventions. This comprehensive review comprises the molecular and genetic pathophysiology, molecular diagnostics, and therapeutic aspects of lean MASH to enunciate a diagnostic approach that combines detailed clinical phenotyping regarding genomic analysis.

Erucic acid promotes intramuscular fat deposition through the PPARγ-FABP4/CD36 pathway

The regulation of intramuscular fat (IMF) accumulation plays a crucial role in determining meat quality in the beef industry. In humans, fat deposition in skeletal muscle is closely associated with insulin resistance and obesity. However, its underlying mechanisms are not fully elucidated. We previously identified erucic acid (EA) as a key metabolite that may affect IMF deposition of beef using omics strategies. By utilizing bovine intramuscular preadipocytes in vitro, the study demonstrates a dose-dependent increase in lipid storage induced by EA, along with mRNA expression levels of transporters FABP4 and CD36. At a mechanistic level, EA triggers ERK1/2 phosphorylation and enhances the expression of PPARγ, FABP4, and CD36, thereby facilitating the formation of lipid droplets within preadipocytes. In vivo experiments conducted in mice support these findings, indicating that EA stimulates fat accumulation in skeletal muscles and enhances the levels of FABP4 and CD36 proteins. These outcomes not only enhance our comprehension of the molecular mechanisms governing IMF deposition but also provide insights into potential strategies for enhancing meat quality and addressing metabolic disorders linked to fat accumulation in skeletal muscles. The findings of the study contribute to existing scholarly knowledge and lay the groundwork for future research endeavors aimed at improving meat quality and metabolic well-being.

From gut microbiota to host genes: A dual-regulatory pathway driving body weight variation in dagu chicken (Gallus gallus domesticus)

During the growth and development of animals, there is an interaction between the gut microbiota and the host genotype. The host genotype can regulate the microbiota, and in turn, the microbiota can influence host gene expression, thereby affecting the animal's production performance. This study explored the dynamic interplay between the gut microbiota and host gene expression in body weight variation in Dagu chicken, an indigenous poultry genetic resource in China. We characterized mucosa-associated microbiota across four gastrointestinal segments (duodenum, jejunum, ileum, cecum) and ileocecal chyme microbiota in 12-week-old Dagu chickens stratified by divergent body weight phenotypes, while simultaneously quantifying region-specific intestinal epithelial transcriptional regulation. 16S rDNA sequencing was employed to identify Firmicutes as the predominant bacterial phylum, with notable differences in the abundance of specific genera (e.g., Ligilactobacillus and Lactobacillus) being observed between the high- or low-body-weight groups. Enhanced biosynthesis pathways were functionally predicted in heavier roosters, whereas reduced nutrient metabolism pathways were contrasted. A conserved functional concordance was observed between regionally predominant differential microbiota and the physiological specialization of corresponding intestinal niches. Functional analysis revealed that the high-body-weight group demonstrated superior capabilities in microbial biosynthesis, whereas the low-body-weight group exhibited enhanced microbial metabolic activity. NAA80 was identified as the common differentially expressed gene across all intestinal epithelial tissues. The Gene Ontology and KEGG pathway analyses revealed elevated nutrient absorption efficiency in the high-body-weight group, while the low-body-weight group demonstrated accelerated cellular renewal rates and shorter cycles. Correlation analysis identified significant associations between gut microbiota and host genes expression profiles, with the majority of correlations being positive. These results suggest a coordinated interaction between microbial communities and host genetic regulation, potentially driving phenotypic differences in body weight performance.

The association between the gut microbiome and antituberculosis drug-induced liver injury

Background

This study aimed to explore the distinct characteristics of the gut microbiota in tuberculosis (TB) patients who experienced liver injury following anti-TB treatment compared with those who did not.

Method

We employed a nested case-control study design, recruiting newly diagnosed pulmonary TB patients at Tangshan Infectious Disease Hospital. Participants were categorized into the Antituberculosis Drug-Induced Liver Injury (ADLI) group and the Non-ADLI group based on the occurrence of liver injury after treatment. Both groups received identical anti-TB regimens. Stool samples were collected from patients who developed liver injury within 2-3 weeks of starting treatment, alongside matched controls during the same timeframe. The samples underwent 16S rDNA sequencing, and clinical data and blood samples were also collected for further analysis. At the same time, we constructed mouse models to explore the effects of different anti-tuberculosis drugs on gut microbiota.

Results

Following anti-TB treatment, we observed a decrease in microbial diversity and significant structural changes in the gut microbiota of TB patients (P < 0.05). At T1, the Non_ADLI_T1 group presented relatively high levels of Phascolarctobacterium, Anaerofustis and Mailhella. In contrast, the ADLI_ T1 group presented elevated levels of Bacteroides, Veillonella, Clavibacter, Corynebacterium, Anaerococcus, Gardnerella, Peptostreptococcus and Lautropia. At T2, the ADLI_T2 group presented increased levels of Enterococcus, Faecalibacterium, unclassified_f__Burkholderiaceae, Cardiobacterium, Ruminococcus_gnavus_group and Tyzzerella_4 than did the Non_ADLI_T2 group. Additionally, the ADLI_T2 group presented decreased levels of Prevotella_9, Akkermansia, Erysipelotrichaceae_UCG-003, Rubrobacter and norank_f__Desulfovibrionaceae than did the Non_ADLI_T2 group. In animal experiments, similar changes to those in the human population were observed in the mouse model compared to the control group. Any single anti-tuberculosis drug or two-drug combination or three-drug combination can cause dysbiosis of the mouse gut microbiota. The signature genera between groups are different and related to the type of anti-tuberculosis drug.

Conclusion

Anti-tuberculosis treatment induces dysbiosis in the gut microbiota of TB patients. Notably, there are significant differences in microbiota characteristics between TB patients with and without liver injury at both onset and during treatment. There are some differences in the characteristics of bacterial flora in liver injury caused by different drugs.

Risk factor analysis and predictive model construction of lean MAFLD: a cross-sectional study of a health check-up population in China

AIM

Cardiovascular disease morbidity and mortality rates are high in patients with metabolic dysfunction-associated fatty liver disease (MAFLD). The objective of this study was to analyze the risk factors and differences between lean MAFLD and overweight MAFLD, and establish and validate a nomogram model for predicting lean MAFLD.

METHODS

This retrospective cross-sectional study included 4363 participants who underwent annual health checkup at Yuyao from 2019 to 2022. The study population was stratified into three groups: non-MAFLD, lean MAFLD (defined as the presence of fatty liver changes as determined by ultrasound in individuals with a BMI < 25 kg/m2), and overweight MAFLD (BMI ≥ 25.0 kg/m2). Subsequent modeling analysis was conducted in a population that included healthy subjects with < 25 kg/m2 (n = 2104) and subjects with lean MAFLD (n = 849). The study population was randomly split (7:3 ratio) to a training vs. a validation cohort. Risk factors for lean MAFLD was identify by multivariate regression of the training cohort, and used to construct a nomogram to estimate the probability of lean MAFLD. Model performance was examined using the receiver operating characteristic (ROC) curve analysis and k-fold cross-validation (k = 5). Decision curve analysis (DCA) was applied to evaluate the clinical usefulness of the prediction model.

RESULTS

The multivariate regression analysis indicated that the triglycerides and glucose index (TyG) was the most significant risk factor for lean MAFLD (OR: 4.03, 95% CI 2.806-5.786). The restricted cubic spline curves (RCS) regression model demonstrated that the relationships between systolic pressure (SBP), alanine aminotransferase (ALT), serum urate (UA), total cholesterol (TCHO), triglyceride (TG), triglyceride glucose (TyG) index, high density lipoprotein cholesterol (HDLC), and MAFLD were nonlinear and the cutoff values for lean MAFLD and overweight MAFLD were different. The nomogram was constructed based on seven predictors: glycosylated hemoglobin A1c (HbA1c), serum ferritin (SF), ALT, UA, BMI, TyG index, and age. In the validation cohort, the area under the ROC curve was 0.866 (95% CI 0.842-0.891), with 83.8% sensitivity and 76.6% specificity at the optimal cutoff. The PPV and NPV was 63.3% and 90.8%, respectively. Furthermore, we used fivefold cross-validation and the average area under the ROC curve was 0.866 (Figure S3). The calibration curves for the model's predictions and the actual outcomes were in good agreement. The DCA findings demonstrated that the nomogram model was clinically useful throughout a broad threshold probability range.

CONCLUSIONS

Lean and overweight MAFLD exhibit distinct metabolic profiles. The nomogram model developed in this study is designed to assist clinicians in the early identification of high-risk individuals with lean MAFLD, including those with a normal BMI but at metabolic risk, as well as those with abnormal blood lipid, glucose, uric acid or transaminase levels. In addition, this model enhances screening efforts in communities and medical screening centers, ultimately ensuring more timely and effective medical services for patients.

Efficacy of composite bacterial deodorant constructed with Camellia sinensis and its in-situ deodorization mechanism on pig manure

Here, we constructed a novel bacterial deodorant (BD) composed of Delftia tsuruhatensis, Paracoccus denitrificans, Pediococcus acidilactici, and Bacillus velezensis. The BD alone removed 64.84 % of NH3, 100 % of H2S, and 63.68 % of comprehensive odor (OU) during a five-day fermentation of pig manure. The effect was enhanced by introducing Camellia sinensis in the composite bacterial deodorant (CBD) treatment, with the removal efficiency (RE) of NH3 and OU being 88.68 % and 88.14 %, respectively. In prolonged trials, maximum RE of NH3, H2S and OU RE reached 90.16 %, 92.32 % and 100 % in CBD group. Bacterial composition of manure revealed that the abundance of odor-producing microbes (Kurthia, Solibacillus, Proteiniphilum and Acholeplasma) and potential pathogens decreased after CBD application. Functional prediction and correlation analyses indicated that the process of nitrification, denitrification and S/N assimilation were facilitated, while S/N mineralization and methanogenesis processes might be inhibited. This deodorant promoted the conversion of malodorous substances into non-odorous forms, establishing an efficient odor removal system in hoggery. Therefore, the bacterial deodorant compounded with C. sinensis has been shown to be an effective method for deodorizing pig farms. This approach will advance the livestock industry toward greener practices and environmental protection, contributing positively to the development of a sustainable agro-ecosystem.

Comparison of diet and exercise on cardiometabolic factors in young adults with overweight/obesity: multiomics analysis and gut microbiota prediction, a randomized controlled trial

The optimal strategy for improving cardiometabolic factors (CMFs) in young obese individuals through diet and exercise remains unclear, as do the potential mechanisms. We conducted an 8-week randomized controlled trial to compare the effects of different interventions in youth with overweight/obesity. Gut microbes and serum metabolites were examined to identify regulating mechanisms. A total of 129 undergraduates were randomly assigned to fiber-rich (FR) diet, rope-skipping (RS), combined FR-RS and control groups. The results showed that single interventions were as effective as combined interventions in improving weight, waist circumference, body fat, and lipid profile compared with control group. Notably, the FR group further reduced low-density lipoprotein (LDL-C) and uric acid (UA) (all p < 0.05). Mediation analysis revealed four gut microbiota-metabolite-host axes in improving CMFs. Additionally, we used machine learning algorithms to further predict individual responses based on baseline gut microbiota composition, with specific microbial genera guiding targeted intervention selection. In conclusion, FR diet and/or RS were effective in improving CMFs, with the FR diet particular effectiveness in reducing LDL-C and UA levels. These benefits may drive by gut microbiome-metabolite-host interactions. Moreover, the predictability of gut microbiota composition supports making targeted decisions in selecting interventions. Trial Registration: NCT04834687.

Characterization of the hepatic flora and metabolome in nonalcoholic fatty liver disease

Background/aim

The purpose of this study was to examine the hepatic bacterial composition and metabolome characteristics of patients with NAFLD using 16S rDNA sequencing and metabolomics. The results of the study revealed substantial differences in hepatic bacterial composition and metabolites between the NAFLD group and the control group. These differences were used to identify potential biomarkers that could be employed to diagnose NAFLD.

Subjects/methods

Liver tissues from 13 patients in the NAFLD group and 12 patients in the control group were collected for microbiota examination.

Results

The bacterial DNA profiles of the liver were significantly different between NAFLD patients and controls. NAFLD patients exhibited an enrichment of Enterobacterales, Mycobacteriales, Pseudomonadales, Flavobacteriales and Xanthomonadales, Sphingomonadales, Lysobact, which was characterised by a lack of erales. At the genus level, the abundance values of Escherichia-Shigella, Rhodococcus, and Chryseobacterium in the NAFLD group were significantly elevated, while the abundance values of Stenotrophomonas, Lawsonella and Sphingobium were significantly reduced. A total of 402 distinct metabolites were identified between the two groups, with 78 metabolites that were up-regulated and 14 metabolites that were down-regulated. The enrichment of metabolic pathways indicated that linoleic acid metabolism was the most significant contributor to the metabolic differences, and lipid metabolism was substantially differentiated. The hepatic metabolite levels were substantially correlated with the changes in hepatic microflora, as demonstrated by the correlation analysis.

Conclusion

Differences in pathogenesis and host physiological function of NAFLD may be attributed to the hepatic flora and metabolomic characteristics. In the future, this presents new opportunities for the investigation of prospective diagnostic and therapeutic targets for NAFLD.

Comparative genomic and metabolomic analysis reveals the potential of a newly isolated Enterococcus faecium B6 involved in lipogenic effects

Evidence has indicated that Enterococcus plays a vital role in non-alcoholic fatty liver disease (NAFLD) development. However, the microbial genetic basis and metabolic potential in the disease are yet unknown. We previously isolated a bacteria Enterococcus faecium B6 (E. faecium B6) from children with NAFLD for the first time. Here, we aim to systematically investigate the potential of strain B6 in lipogenic effects. The lipogenic effects of strain B6 were explored in vitro and in vivo. The genomic and functional characterizations were investigated by whole-genome sequencing and comparative genomic analysis. Moreover, the metabolite profiles were unraveled by an untargeted metabolomic analysis. We demonstrated that strain B6 could effectively induce lipogenic effects in the liver of mice. Strain B6 contained a circular chromosome and two circular plasmids and posed various functions. Compared to the other two probiotic strains of E. faecium, strain B6 exhibited unique functions in pathways of ABC transporters, phosphotransferase system, and amino sugar and nucleotide sugar metabolism. Moreover, strain B6 produced several metabolites, mainly enriched in the protein digestion and absorption pathway. The unique potential of strain B6 in lipogenic effects was probably associated with glycolysis, fatty acid synthesis, and glutamine and choline transport. This study pioneeringly revealed the metabolic characteristics and specific detrimental traits of strain B6. The findings provided new insights into the underlying mechanisms of E. faecium in lipogenic effects, and laid essential foundations for further understanding of E. faecium-related disease.

Multi-omics analysis reveals that agaro-oligosaccharides with different degrees of polymerization alleviate colitis in mice by regulating intestinal flora and arginine synthesis

Inflammatory bowel disease (IBD) is a common chronic disease with a complex etiology, characterized by body weight loss, intestinal barrier damage, and an imbalance of intestinal flora, posing a significant threat to people's health. In this work, we studied whether safer natural active agaro-oligosaccharides (AOSs) benefit mice with IBD and elucidated their underlying mechanisms. The findings indicated that oral administration of agarobiose (A2), agarotriose (A3), and agarotetraose (A4) contributed to alleviating body weight loss and colon shortening, as well as enhancing IL-10 levels while reducing IL-6, IL-1β, and TNF-α. AOSs improved colon disruption, reduced the number of goblet cells caused by DSS, and enhanced the expression of Muc2, ZO-1, and occludin-1 to repair the intestinal barrier. It is noteworthy that A3 demonstrated superior outcomes in the evaluated AOSs relative to A2 and A4. This was evidenced by an increase in Bacteroidota and reduced Firmicutes at the phylum level, which corrected DSS-induced intestinal dysbiosis and significantly restored disrupted metabolic pathways, including amino acid and lipid metabolism. The differential metabolites between the AOS treatment groups and the model group were mainly enriched in arginine synthesis with co-regulated critical substances N-acetyl-L-citrulline and N2-acetylornithine, which alleviated colitis. This evidence offers a fresh perspective on the potential application of AOSs as functional foods to improve intestinal inflammation and metabolism.

Gut microbiome impact on childhood allergic rhinitis and house dust mite IgE responses

BACKGROUND

The correlation between the gut microbiota and airway inflammation in childhood allergic rhinitis (AR), particularly concerning allergen exposure, remains insufficiently explored. This study aimed to link gut microbiota changes with house dust mite (HDM)-specific IgE responses in pediatric AR.

METHODS

Using metagenomic shotgun sequencing, we compared the fecal microbiota of 60 children with HDM-AR to 48 healthy controls (HC), analyzing the link to IgE reactions. We examined the effects of oral Escherichia (E.) fergusonii treatment in mice sensitized with ovalbumin and HDM on allergic symptoms, mucosal cell infiltration, Th1/Th2/Tregs balance in the spleen, serum cytokine levels, and E. fergusonii presence in feces.

RESULTS

Children with HDM-AR have a less diverse gut microbiome and lower levels of E. fergusonii compared to controls, with a negative correlation between E. fergusonii abundance and HDM-specific IgE levels. In mice sensitized with OVA and HDM, oral administration of E. fergusonii improved allergic symptoms, reduced nasal eosinophils/mast cells infiltration and adjusted Th cell populations towards a non-allergic profile in splenic lymphocytes with exception of IFN-γ change in serum.

CONCLUSION

These findings underline the potential of targeting gut microbiota, particularly E. fergusonii, in managing childhood HDM-AR, suggesting a promising approach for future interventions.

IMPACT

The composition and distribution of gut microbiota in children with HDM-AR are significant changed. The abundance of Escherichia genus is decreased in HDM-AR children. HDM-specific IgE levels are strongly negatively associated with E. fergusonii abundance. Oral administration of E. fergusonii effectively suppresses allergic responses in murine model. These findings offer novel insights into the diagnosis and treatment of HDM-AR, which suggested that E. fergusonii holds promise as a potential therapeutic avenue for managing HDM-AR.

Autophagy Improves Inflammatory Response in Sepsis Accompanied by Changes in Gut Microbiota

Background: Sepsis is defined as a life-threatening disease. Autophagy and the microbiome are increasingly connected with sepsis. The aim of this study was to investigate the protective effect of autophagy and the possible mechanisms. Methods: The septic rat model was established by cecal ligation perforation (CLP). Rapamycin (Rap), 3-methyladenine (3-MA), and chloroquine (CQ) were administered to interfere autophagy. Western blot (WB) was used to detect the expression of key proteins in autophagy. Hematoxylin and eosin (H&E) staining and enzyme-linked immunosorbent assays (ELISAs) were used to identify the effect of autophagy on various organs. 16S ribosomal RNA gene sequencing was used to analyze the changes of the gut microbiota. Results: Rap significantly upregulated the expression of key autophagy proteins, and 3-MA reduced the relative expression compared to the CLP group. The autophagic flux showed a corresponding trend. Interestingly, the autophagy inducer significantly decreased the mortality and the lipopolysaccharide (LPS) level in serum compared with the CLP group. Autophagy activation significantly improves the inflammatory response in sepsis. Histopathological sections showed that CLP destroyed the tight junctions between ileal epithelial cells, while autophagy induction reversed the damage. The sequencing results showed that autophagy activation increased the alpha diversity and alterted the composition and structure of gut microbiota. The abundance of Proteobacteria was markedly decreased in the Rap group, whereas Bacteroidetes was notably increased compared with the CLP group. Additionally, the protective effect of autophagy further changed the biomarkers in the microbial community. The top 35 functions in each sample were analyzed to obtain 18 genes including RNA synthesis, ATP binding and transport, chromosome assignment, osmotic polysaccharide transport, transcytosis, and methylation. Conclusion: Autophagy is able to improve inflammation and may directly or indirectly regulate the microbiota of septic rats. Autophagy may be an important target for future clinical interventions in the treatment of sepsis.

Maslinic acid alleviates alcoholic liver injury in mice and regulates intestinal microbiota via the gut-liver axis

BACKGROUND

Maslinic acid (MA), a pentacyclic triterpene acid, is widely distributed in natural plants and mainly found in the fruit and leaves of olives and hawthorn. MA has been reported as having many health-promoting functions, such as anticancer, anti-inflammation and neuroprotective activities. According to previous study, hawthorn extract has certain hepatoprotective effects. However, the detailed mechanism is still unclear, especially the effect of MA on gut microbiota.

RESULTS

Our study reveals that MA effectively counteracts alcohol-induced liver injury and oxidative stress. It mitigates alcohol-induced intestinal barrier damage, reverses increased permeability and reduces translocation of lipopolysaccharide (LPS). This prevents LPS/Toll-like receptor 4 activation, leading to decreased TNF-α and IL-1β production. Furthermore, MA rebalances gut microbiota by reversing harmful bacterial abundance and enhancing beneficial bacteria post-alcohol consumption.

CONCLUSION

MA, through modulation of gut microbiota, alleviates alcohol-induced liver injury via the gut-liver axis. These findings support the potential use of MA as a functional food ingredient for preventing or treating alcoholic liver disease. © 2024 Society of Chemical Industry.

Gan-jiang-ling-zhu decoction improves steatohepatitis by regulating gut microbiota-mediated 12-tridecenoic acid inhibition

Introduction: Gan-jiang-ling-zhu (GJLZ) decoction is a classical traditional Chinese medicine prescription. Through invigorating yang, activating qi and dissipating dampness, GJLZ decoction is widely applied for the treatment of chronic digestive disease, including nonalcoholic fatty liver disease. However, efficacy and mechanism of GJLZ decoction behind nonalcoholic steatohepatitis (NASH) treatment remains unelucidated. Methods: NASH was induced in mice, followed by treatment with GJLZ decoction. Various methods including hematoxylin-eosin, oil red O staining, and triglyceride analysis were employed to evaluate the treatment effects of GJLZ decoction on NASH. Gut microbiota, metabolomics, cell viability assays, immunofluorescence and Western blotting were performed to unveil the mechanism behind GJLZ decoction. Results: GJLZ decoction treatment significantly improved hepatic steatosis in mice with NASH. It led to remodeling of gut flora and metabolite structures, including the 12-tridecenoic acid level. 12-Tridecenoic acid aggravated hepatic steatosis by promoting acetyl-coenzyme A carboxylase alpha (ACC) expression and inhibiting carnitine palmitoyltransferase 1A (CPT1A) expression. GJLZ decoction treatment reduced the 12-tridecenoic acid level, inhibited ACC activity and promoted CPT1A expression. Conclusion: Our results demonstrated that 12-tridecenoic acid aggravated hepatic steatosis by affecting the ACC-CPT1A axis and GJLZ decoction treatment effectively reduced the 12-tridecenoic acid level and improved steatosis.

MAFLD: an ideal framework for understanding disease phenotype in individuals of normal weight

The prevalence of metabolic dysfunction-associated fatty liver disease (MAFLD) is significant, impacting almost one-third of the global population. MAFLD constitutes a primary cause of end-stage liver disease, liver cancer and the need for liver transplantation. Moreover, it has a strong association with increased mortality rates due to various extrahepatic complications, notably cardiometabolic diseases. While MAFLD is typically correlated with obesity, not all individuals with obesity develop the disease and a significant percentage of MAFLD occurs in patients without obesity, termed lean MAFLD. The clinical features, progression and underlying physiological mechanisms of patients with lean MAFLD remain inadequately characterized. The present review aims to provide a comprehensive summary of current knowledge on lean MAFLD and offer a perspective on defining MAFLD in individuals with normal weight. Key to this process is the concept of metabolic health and flexibility, which links states of dysmetabolism to the development of lean MAFLD. This perspective offers a more nuanced understanding of MAFLD and its underlying mechanisms and highlights the importance of considering the broader metabolic context in which the disease occurs. It also bridges the knowledge gap and offers insights that can inform clinical practice.

Ferroptosis: a potential bridge linking gut microbiota and chronic kidney disease

Ferroptosis is a novel form of lipid peroxidation-driven, iron-dependent programmed cell death. Various metabolic pathways, including those involved in lipid and iron metabolism, contribute to ferroptosis regulation. The gut microbiota not only supplies nutrients and energy to the host, but also plays a crucial role in immune modulation and metabolic balance. In this review, we explore the metabolic pathways associated with ferroptosis and the impact of the gut microbiota on host metabolism. We subsequently summarize recent studies on the influence and regulation of ferroptosis by the gut microbiota and discuss potential mechanisms through which the gut microbiota affects ferroptosis. Additionally, we conduct a bibliometric analysis of the relationship between the gut microbiota and ferroptosis in the context of chronic kidney disease. This analysis can provide new insights into the current research status and future of ferroptosis and the gut microbiota.

Effects of herbal dregs supplementation of Salvia miltiorrhiza and Isatidis Radix residues improved production performance and gut microbiota abundance in late-phase laying hens

The present study was designed to evaluate the effect of a mixture of Chinese medicinal residues (CMRs) consisting of Salvia miltiorrhiza residues (SMR) and Isatidis Radix residues (IRR) on productive performance, egg quality, serum lipid and hormone levels, liver and blood antioxidant capacity, oviduct inflammation levels, and gut microbiota in the late-laying stage. A total of 288 fifty-four-week-old BaShang long-tailed hens were divided into four groups. The feed trial period was 8 weeks. The control group was fed the basic diet as a CCMR group, supplemented with 3, 4, and 6% for the experimental groups LCMR, MCMR, and HCMR. The egg production rate of the MCMR group was 8.1% higher than that of the CCMR group (p < 0.05). Serum triglyceride (TG) levels of hens of the CMR-supplemented group were significantly decreased than those of the CCMR group (p < 0.05). The group supplemented with different levels of CMR had significantly higher serum HDL-C levels compared with the control group (p < 0.05). Follicle-stimulating hormone (FSH) and luteinizing hormone (LH) levels were remarkably increased for the LCMR and MCMR groups and significantly decreased for the HCMR group compared to CCMR (p < 0.05). Serum and liver glutathione peroxidase (GSH-PX) activities were significantly increased, and malondialdehyde (MDA) levels were significantly decreased in the MCMR group compared to the CCMR group (p < 0.05). The expression levels of tubal inflammatory factor markers (IL-4, IL-1β, TNF-α) in the MCMR and HCMR groups were consistent with the pathological findings of the sections. As for cecal microbiota, supplementation with CMR affected the alpha diversity of the cecum microbiome at the genus level. The Shannon index was significantly higher in the MCMR group than in the CCMR and HCMR groups (p < 0.05). Supplementation with different levels of CMR mainly regulated the ratio of intestinal Firmicutes to Bacteroidetes and the abundance of phyla such as Proteobacteria. In addition, CMR supplementation at different levels in the diet enriched lipid-metabolizing bacteria, such as Bacteroides and Ruminococcus_gnavus_group. Furthermore, according to linear discriminant analysis (LDA) effect size (LEfSe) analysis, the MCMR group showed an increase in the number of short-chain fatty acid-producing bacteria Romboutsia and fiber-degrading specialized bacteria Monoglobus. Therefore, supplementation of appropriate amounts of CMR to the diet of laying hens enhanced reproductive hormone levels, hepatic antioxidant capacity, and lipid metabolism, alleviated the levels of oviductal inflammatory factors, and modulated the abundance structure of bacterial flora to improve the late-laying performance and egg quality. The results of the current study showed that CMR is a beneficial feed supplement for chickens when added in moderation.

Isoleucine‐restricted diets improve high‐fat diet‐induced nonalcoholic fatty liver disease via regulating insulin resistance and gut microbiota

Obesity, caused by a long‐term high‐fat diet, is a risk factor for insulin resistance and nonalcoholic fatty liver disease (NAFLD). The gut microbiota plays an important role in NAFLD development by producing lipopolysaccharides (LPS). Isoleucine (ILE), as one of the branched‐chain amino acids (BCAAs), has a negative effect on glucose and lipid metabolism in obese mice. Therefore, we speculated that isoleucine‐restricted diets could prevent high‐fat diet‐induced insulin resistance and NAFLD. For this purpose, 30 C57BL/6J mice received a control check diet (CK), a high‐fat diet (HFD), and a isoleucine‐restricted diet (IR) for 12 weeks, respectively. The current study revealed that IR diets reversed HFD‐induced weight gain, increased fasting glucose levels, and lipid metabolism disorder. Furthermore, IR diets attenuated HFD‐induced hepatic inflammation by regulating the LPS/TLR4/NF‐κB signaling pathway. Moreover, hepatic insulin resistance and gluconeogenesis disorder were significantly improved by IR diets. In addition, IR diets reshaped HFD‐induced gut microbiota imbalance, reflected in decreasing the proportion of Proteobacteria phylum and LPS contents. Taken together, our studies support that restricting isoleucine in high‐fat diets was a novel means of preventing obesity‐induced NAFLD and insulin resistance.

Development of small intestinal barrier function and underlying mechanism in Chinese indigenous and Duroc piglets during suckling and weaning periods

This study explored the developmental changes in small intestinal barrier function and the potential regulatory roles of intestinal microbiota and metabolites in different breeds of piglets during suckling and weaning periods. Taoyuan black (TB), Xiangcun black (XB), and Duroc (DR) piglets (10 litters per breed; half male and half female) were selected for sampling to evaluate the intestinal barrier-related indexes and intestinal microbiota and metabolites at 1, 10, 21 (weaned), and 24 (3 d after weaning) d old. The results showed that weaning led to severe shedding of small intestinal microvilli and sparse microvilli arrangement. D-lactate level in the ileum of TB and XB piglets during suckling and weaning periods was lower (P < 0.01) than that of DR piglets, as well as the ileal diamine oxidase level at 1 d old. The expression level of mucin 1 was higher (P < 0.05) in the ileum of TB and XB piglets than that of DR piglets, and it was the highest in the ileum of TB piglets at 21 d old. The expression levels of mucin 2 and mucin 13 were higher (P < 0.10) in TB and XB piglets than those of DR piglets at 21 d old, whereas mucin 2 and mucin 13 in the ileum of TB and XB piglets were higher (P < 0.05) than those of DR piglets at 24 d old. TB and XB piglets had a lower relative abundance of Escherichia_Shigella at 21 and 24 d old, but they had higher Streptococcus at 1 and 24 d old than DR piglets (P < 0.01). Differential metabolites between the three breeds of piglets were mainly related to oxidative phosphorylation, steroid biosynthesis, and bile acid synthesis. Collectively, these findings suggest that different pig breeds present differences in the development of the small intestinal barrier function. Compared with DR piglets, TB and XB piglets had higher intestinal permeability during the suckling period and a stronger intestinal mechanical barrier after weaning. Moreover, intestinal microbiota and metabolites are the key factors for developing small intestinal barrier functions in different breeds of piglets.

Identification of commensal gut bacterial strains with lipogenic effects contributing to NAFLD in children

Gut microbiota is known to have a significant impact on nonalcoholic fatty liver disease (NAFLD), particularly in children with obesity. However, the specific functions of microbiota at the strain level in this population have not been fully elucidated. In this study, we successfully isolated and identified several commensal gut bacterial strains that were dominant in children with obesity and NAFLD. Among these, four novel isolates were found to have significant lipogenic effects in vitro. These strains exhibited a potential link to hepatocyte steatosis by regulating the expression of genes involved in lipid metabolism and inflammation. Moreover, a larger cohort analysis confirmed that these identified bacterial strains were enriched in the NAFLD group. The integrated analysis of these strains effectively distinguished NASH from NAFL. These four strains might serve as potential biomarkers in children with NAFLD. These findings provided new insights into the exploration of therapeutic targets for NAFLD.

Natural lipid nanoparticles extracted from Morus nigra L. leaves for targeted treatment of hepatocellular carcinoma via the oral route

The clinical application of conventional medications for hepatocellular carcinoma treatment has been severely restricted by their adverse effects and unsatisfactory therapeutic effectiveness. Inspired by the concept of 'medicine food homology', we extracted and purified natural exosome-like lipid nanoparticles (LNPs) from black mulberry (Morus nigra L.) leaves. The obtained MLNPs possessed a desirable hydrodynamic particle size (162.1 nm), a uniform size distribution (polydispersity index = 0.025), and a negative surface charge (-26.6 mv). These natural LNPs were rich in glycolipids, functional proteins, and active small molecules (e.g., rutin and quercetin 3-O-glucoside). In vitro experiments revealed that MLNPs were preferentially internalized by liver tumor cell lines via galactose receptor-mediated endocytosis, increased intracellular oxidative stress, and triggered mitochondrial damage, resulting in suppressing the viability, migration, and invasion of these cells. Importantly, in vivo investigations suggested that oral MLNPs entered into the circulatory system mainly through the jejunum and colon, and they exhibited negligible adverse effects and superior anti-liver tumor outcomes through direct tumor killing and intestinal microbiota modulation. These findings collectively demonstrate the potential of MLNPs as a natural, safe, and robust nanomedicine for oral treatment of hepatocellular carcinoma.

Cultivated Enterococcus faecium B6 from children with obesity promotes nonalcoholic fatty liver disease by the bioactive metabolite tyramine

Gut microbiota plays an essential role in nonalcoholic fatty liver disease (NAFLD). However, the contribution of individual bacterial strains and their metabolites to childhood NAFLD pathogenesis remains poorly understood. Herein, the critical bacteria in children with obesity accompanied by NAFLD were identified by microbiome analysis. Bacteria abundant in the NAFLD group were systematically assessed for their lipogenic effects. The underlying mechanisms and microbial-derived metabolites in NAFLD pathogenesis were investigated using multi-omics and LC-MS/MS analysis. The roles of the crucial metabolite in NAFLD were validated in vitro and in vivo as well as in an additional cohort. The results showed that Enterococcus spp. was enriched in children with obesity and NAFLD. The patient-derived Enterococcus faecium B6 (E. faecium B6) significantly contributed to NAFLD symptoms in mice. E. faecium B6 produced a crucial bioactive metabolite, tyramine, which probably activated PPAR-γ, leading to lipid accumulation, inflammation, and fibrosis in the liver. Moreover, these findings were successfully validated in an additional cohort. This pioneering study elucidated the important functions of cultivated E. faecium B6 and its bioactive metabolite (tyramine) in exacerbating NAFLD. These findings advance the comprehensive understanding of NAFLD pathogenesis and provide new insights for the development of microbe/metabolite-based therapeutic strategies.

Gut microbiota dynamics in a 1-year follow-up after adult liver transplantation in Northeast China

Background: Liver transplantation (LTx) is the most effective treatment for end-stage liver diseases. Gut microorganisms influence the host physiology. We aim to profile the dynamics of gut microbiota in the perioperative period and a 1-year follow-up of LTx recipients in Northeast China. Methods: A total of 257 fecal samples were longitudinally collected from 85 LTx patients using anal swabs from pre-LTx to 1-year post-LTx. A total of 48 fecal samples from end-stage liver disease patients without LTx served as the control. 16S rRNA sequencing was used to analyze gut microbiota diversity, bacterial genera, phenotype classification, and metabolic pathways. Results: The diversity of gut microbiota decreased significantly after transplantation, accompanied by a profound change in the microbial structure, which is characterized by increased abundance of facultative anaerobic bacteria dominated by g_Enterococcus and reduced anaerobic bacteria composition. Predicted functional analysis also revealed disturbances in the metabolic pathway of the gut microbiota. After LTx, the diversity of microbiota gradually recovered but to a less preoperative level after 1 year of recovery. Compared with pre-transplantation, the microbiome structure was characterized by an increase in Acidaminococcus and Acidithiobacillus after 1 year of transplantation. Conclusion: LTx and perioperative treatment triggered gut microbial dysbiosis. The gut microbiota was restructured after LTx to near to but significantly differed from that of pre-LTx.

Gut microbiota landscape and potential biomarker identification in female patients with systemic lupus erythematosus using machine learning

Objectives

Systemic Lupus Erythematosus (SLE) is a complex autoimmune disease that disproportionately affects women. Early diagnosis and prevention are crucial for women's health, and the gut microbiota has been found to be strongly associated with SLE. This study aimed to identify potential biomarkers for SLE by characterizing the gut microbiota landscape using feature selection and exploring the use of machine learning (ML) algorithms with significantly dysregulated microbiotas (SDMs) for early identification of SLE patients. Additionally, we used the SHapley Additive exPlanations (SHAP) interpretability framework to visualize the impact of SDMs on the risk of developing SLE in females.

Methods

Stool samples were collected from 54 SLE patients and 55 Negative Controls (NC) for microbiota analysis using 16S rRNA sequencing. Feature selection was performed using Elastic Net and Boruta on species-level taxonomy. Subsequently, four ML algorithms, namely logistic regression (LR), Adaptive Boosting (AdaBoost), Random Forest (RF), and eXtreme gradient boosting (XGBoost), were used to achieve early identification of SLE with SDMs. Finally, the best-performing algorithm was combined with SHAP to explore how SDMs affect the risk of developing SLE in females.

Results

Both alpha and beta diversity were found to be different in SLE group. Following feature selection, 68 and 21 microbiota were retained in Elastic Net and Boruta, respectively, with 16 microbiota overlapping between the two, i.e., SDMs for SLE. The four ML algorithms with SDMs could effectively identify SLE patients, with XGBoost performing the best, achieving Accuracy, Sensitivity, Specificity, Positive Predictive Value, Negative Predictive Value, and AUC values of 0.844, 0.750, 0.938, 0.923, 0.790, and 0.930, respectively. The SHAP interpretability framework showed a complex non-linear relationship between the relative abundance of SDMs and the risk of SLE, with Escherichia_fergusonii having the largest SHAP value.

Conclusions

This study revealed dysbiosis in the gut microbiota of female SLE patients. ML classifiers combined with SDMs can facilitate early identification of female patients with SLE, particularly XGBoost. The SHAP interpretability framework provides insight into the impact of SDMs on the risk of SLE and may inform future scientific treatment for SLE.

Continuous oral exposure to micro- and nanoplastics induced gut microbiota dysbiosis, intestinal barrier and immune dysfunction in adult mice

Micro/nanoplastics in the environment can be ingested by organisms and spread throughout the food chain, ultimately posing a threat to human health. However, the risk of continuous oral exposure in mammals remains unresolved. In this study, we utilized a continuous gavage mouse model to investigate the potential intestinal risks associated with oral exposure to polystyrene micro/nanoplastics (PS-MNPs) with environmentally relevant concentrations. The effects of PS-MNPs with different particle sizes on the gut microbiota, intestinal barrier, and intestinal immune function were evaluated. PS-MNPs can accumulate in the intestine after oral exposure and alter the composition of the gut microbiota. Exposure to PS-MNPs significantly reduced the ratio of Firmicutes to Bacteroidetes as well as the number of potentially beneficial bacteria in the gut, while the number of potentially harmful bacteria significantly increased. The short-chain fatty acids metabolized by gut microbiota were significantly changed by PS-MNPs. Exposure to PS-MNPs disrupts the function of the intestinal barrier and leads to inflammation in the intestines. The levels of secretory immunoglobulin A in the intestine and the differentiation of CD4+ and CD8+ T cells in mesenteric lymph nodes were significantly decreased by PS-MNPs. Moreover, the impact of PS-MNPs on mammalian intestinal health is influenced by the exposure duration and particle size, rather than the concentration. It also suggests that nanoplastics may pose more severe environmental risks.

Total Astragalus saponins can reverse type 2 diabetes mellitus-related intestinal dysbiosis and hepatic insulin resistance in vivo

Objective

Intestinal flora homeostasis in rats with type 2 diabetes mellitus (T2DM) was evaluated to explore the effects of total Astragalus saponins (TAS) on hepatic insulin resistance (IR).

Methods

Six-week-old male Sprague-Dawley rats were fed high-fat and high-sugar diet for 4 weeks and intraperitoneally injected with streptozotocin to induce T2DM, and they were then randomly divided into control, model, metformin, and TAS groups. Stool, serum, colon, and liver samples were collected after 8 weeks of drug administration for relevant analyses.

Results

TAS reduced fasting blood glucose, 2-hour postprandial blood glucose, area under the curve of oral glucose tolerance test, glycated serum protein, homeostasis model assessment of insulin resistance, total cholesterol, triglyceride, and low-density lipoprotein cholesterol levels in T2DM rats but increased insulin, C-peptide, and high-density lipoprotein cholesterol levels. Moreover, TAS improved the morphology and structure of liver and colon tissues and improved the composition of the intestinal microbiome and bacterial community structure at different taxonomic levels. In addition, TAS increased the protein expression of hepatic IRS-1, PI3K, PDK1, and p-AKT and decreased the protein expression of p-GSK-3β. Meanwhile, TAS increased the mRNA expression of liver PDK1, PI3K, and GS and decreased the mRNA expression of GSK-3β.

Conclusion

TAS can ameliorate T2DM-related abnormal glucose and blood lipid metabolism, intestinal dysbiosis, and IR.

Lonicera caerulea L. polyphenols improve short-chain fatty acid levels by reshaping the microbial structure of fermented feces in vitro

Increasing evidence suggests that the pathogenesis of type 2 diabetes mellitus (T2DM) is closely related to the gut microbiota. Polyphenols have been shown to alleviate T2DM, but the effects of L. caerulea L. polyphenols (LPs) on the gut microbiota and metabolites remain elusive. In this study, the inhibitory effects of fermented L. caerulea L. polyphenols (FLPs) and unfermented L. caerulea L. polyphenols (ULPs) on α-amylase and α-glucosidase and the impact of LP on the gut microbiota and metabolites were investigated. Furthermore, the relationship between the two was revealed through correlation analysis. The results showed that ULP and FLP had the highest inhibitory rates against α-amylase and α-glucosidase at 4 mg ml-1, indicating a strong inhibitory ability. In addition, LP plays a regulatory role in the concentration of short-chain fatty acids (SCFAs) and tends to restore them to their normal levels. LP reversed the dysbiosis of the gut microbiota caused by T2DM, as evidenced by an increase in the abundance of bacterial genera such as Lactobacillus, Blautia, and Bacteroides and a decrease in the abundance of bacterial genera such as Escherichia-Shigella and Streptococcus. Similarly, after LP intervention, the relationships among microbial species became more complex and interconnected. In addition, the correlation between the gut microbiota and metabolites was established through correlation analysis. These further findings clarify the mechanism of action of LP against T2DM and provide a new target for T2DM interventions.

Lactobacillus johnsonii Attenuates Liver Steatosis and Bile Acid Dysregulation in Parenteral Nutrition-Fed Rats

Parenteral nutrition (PN), a vital therapy for patients with intestinal failure, can lead to the development of parenteral nutrition-associated liver disease (PNALD). In this study, we aimed to investigate the role of Lactobacillus johnsonii (L. johnsonii) in a rat model of PNALD. Total parenteral nutrition (TPN)-fed rats were used to assess the role of L. johnsonii in liver steatosis, bile acid metabolism, gut microbiota, and hepatocyte apoptosis. We observed a depletion of L. johnsonii that was negatively correlated with the accumulation of glycochenodeoxycholic acid (GCDCA), a known apoptosis inducer, in rats subjected to TPN. L. johnsonii attenuated TPN-induced liver steatosis by inhibiting fatty acid synthesis and promoting fatty acid oxidation. TPN resulted in a decrease in bile acid synthesis and biliary bile secretion, which were partially restored by L. johnsonii treatment. The gut microbial profile revealed depletion of pathogenic bacteria in L. johnsonii-treated rats. L. johnsonii treatment reduced both hepatic GCDCA levels and hepatocyte apoptosis compared with the TPN group. In vitro, L. johnsonii treatment inhibited GCDCA-induced hepatocyte apoptosis via its bile salt hydrolase (BSH) activity. Our findings suggest that L. johnsonii protects against liver steatosis, bile acid dysregulation, and hepatocyte apoptosis in TPN-fed rats.

d-Aspartate in Low-Protein Diets Improves the Pork Quality by Regulating Energy and Lipid Metabolism via the Gut Microbes

d-Aspartate is critical in maintaining hormone secretion and reproductive development in mammals. This study investigated the mechanism of different d-aspartate levels (0, 0.005, 0.05, and 0.5% d-aspartate) in low-protein diets on growth performance and meat quality by mediating the gut microbiota alteration in pigs. We found that adding 0.005% d-aspartate to a low-protein diet could dramatically improve the growth performance during the weaned and growing periods. Dietary d-aspartate with different levels markedly increased the back fat, and 0.5% d-aspartate significantly increased the redness in 24 h and reduced the shear force of the longissimus dorsi (LD) muscle. Moreover, d-aspartate treatments decreased the mRNA expression of MyHC II a and MyHC IIx in the LD muscle. The protein expression of MyH1, MyH7, TFAM, FOXO1, CAR, UCP2, and p-AMPK was upregulated by 0.005% d-aspartate. Additionally, the abundance of Alistipes, Akkermansia, and the [Eubacterium]_coprostanoligenes_group in the intestinal chyme of pigs was significantly decreased by d-aspartate treatments at the genus level, which was also accompanied by a significant decrease in acetate content. These differential microorganisms were significantly correlated with meat quality characteristics. These results indicated that d-aspartate in low-protein diets could improve the growth performance and meat quality in pigs by regulating energy and lipid metabolism via the alteration of gut microbiota.

Water-Insoluble Polysaccharide Extracted from Poria cocos Alleviates Antibiotic-Associated Diarrhea Based on Regulating the Gut Microbiota in Mice

Antibiotics are very effective in treating a variety of bacterial infections, while clinical overuse of antibiotics can lead to diseases such as antibiotic-associated diarrhea. Numerous studies have shown that natural polysaccharides can be used as prebiotics to alleviate antibiotic-associated diarrhea (AAD). Poria cocos is a medicinal and edible mushroom widely used for thousands of years in China, and our former study demonstrated that water-insoluble polysaccharide (PCY) has the potential prebiotic function. Therefore, we simulated the digestion and fermentation of PCY using feces from volunteers, and then administered it to C57BL/6 mice with AAD to study its effects on the gut microbiota and metabolites. The results indicated that PCY effectively alleviated the symptoms of AAD in mice, restored the intestinal barrier function, improved the content of short-chain fatty acids (SCFAs), decreased the level of inflammatory cytokines, and changed the structure of gut microbiota by increasing the relative abundance of norank_f__Muribaculaceae and unclassified_f__Lachnospiraceae, and decreasing that of Escherichia-Shigella, Staphylococcus and Acinetobacter. This study further demonstrated that PCY is an effective functional prebiotic for improving AAD disease, and provided a new avenue and insight for developing PCY as a functional food or prebiotic for alleviating gastrointestinal diseases.

Epigenetic Regulation in Lean Nonalcoholic Fatty Liver Disease

Nonalcoholic fatty liver disease (NAFLD), the most prominent cause of chronic liver disease worldwide, is a rapidly growing epidemic. It consists of a wide range of liver diseases, from steatosis to nonalcoholic steatohepatitis, and predisposes patients to liver fibrosis, cirrhosis, and even hepatocellular carcinoma. NAFLD is strongly correlated with obesity; however, it has been extensively reported among lean/nonobese individuals in recent years. Although lean patients demonstrate a lower prevalence of diabetes mellitus, central obesity, dyslipidemia, hypertension, and metabolic syndrome, a percentage of these patients may develop steatohepatitis, advanced liver fibrosis, and cardiovascular disease, and have increased all-cause mortality. The pathophysiological mechanisms of lean NAFLD remain vague. Studies have reported that lean NAFLD demonstrates a close association with environmental factors, genetic predisposition, and epigenetic modifications. In this review, we aim to discuss and summarize the epigenetic mechanisms involved in lean NAFLD and to introduce the interaction between epigenetic patterns and genetic or non genetic factors. Several epigenetic mechanisms have been implicated in the regulation of lean NAFLD. These include DNA methylation, histone modifications, and noncoding-RNA-mediated gene regulation. Epigenetics is an area of special interest in the setting of lean NAFLD as it could provide new insights into the therapeutic options and noninvasive biomarkers that target this under-recognized and challenging disorder.

Escherichia coli Promotes Endothelial to Mesenchymal Transformation of Liver Sinusoidal Endothelial Cells and Exacerbates Nonalcoholic Fatty Liver Disease Via Its Flagellin

BACKGROUND＆AIMS: Gut bacteria translocate into the liver through a disrupted gut vascular barrier, which is an early and common event in the development of nonalcoholic fatty liver disease (NAFLD). Liver sinusoidal endothelial cells (LSECs) are directly exposed to translocated gut microbiota in portal vein blood. Escherichia coli, a commensal gut bacterium with flagella, is markedly enriched in the gut microbiota of patients with NAFLD. However, the impact of E coli on NAFLD progression and its underlying mechanisms remains unclear.

METHODS

The abundance of E coli was analyzed by using 16S ribosomal RNA sequencing in a cohort of patients with NAFLD and healthy controls. The role of E coli was assessed in NAFLD mice after 16 weeks of administration, and the features of NAFLD were evaluated. Endothelial to mesenchymal transition (EndMT) in LSECs induced by E coli was analyzed through Western blotting and immunofluorescence.

RESULTS

The abundance of gut Enterobacteriaceae increased in NAFLD patients with severe fat deposition and fibrosis. Importantly, translocated E coli in the liver aggravated hepatic steatosis, inflammation, and fibrosis in NAFLD mice. Mechanistically, E coli induced EndMT in LSECs through the TLR5/MYD88/TWIST1 pathway during NAFLD development. The toll-like receptor 5 inhibitor attenuated E coli-induced EndMT in LSECs and liver injury in NAFLD mice. Interestingly, flagellin-deficient E coli promoted less EndMT in LSECs and liver injury in NAFLD mice.

CONCLUSIONS

E coli promoted the development of NAFLD and promoted EndMT in LSECs through toll-like receptor 5/nuclear factor kappa B-dependent activation of TWIST1 mediated by flagellin. Therapeutic interventions targeting E coli and/or flagellin may represent a promising candidate for NAFLD treatment.

Experimental models of fatty liver diseases: Status and appraisal

Fatty liver diseases, including alcohol-associated liver disease (ALD) and nonalcoholic fatty liver disease nonalcoholic fatty liver disease (NAFLD), affect a large number of people worldwide and become one of the major causes of end-stage liver disease, such as liver cirrhosis and hepatocellular carcinoma (HCC). Unfortunately, there are currently no approved pharmacological treatments for ALD or NAFLD. This situation highlights the urgent need to explore new intervention targets and discover effective therapeutics for ALD and NAFLD. The lack of properly validated preclinical disease models is a major obstacle to the development of clinical therapies. ALD and NAFLD models have been in the development for decades, but there are still no models that recapitulate the full spectrum of ALD and NAFLD. Throughout this review, we summarize the current in vitro and in vivo models used for research on fatty liver diseases and discuss the advantages and limitations of these models.

Interaction between mucus layer and gut microbiota in non-alcoholic fatty liver disease: Soil and seeds

ABSTRACT

The intestinal mucus layer is a barrier that separates intestinal contents and epithelial cells, as well as acts as the "mucus layer-soil" for intestinal flora adhesion and colonization. Its structural and functional integrity is crucial to human health. Intestinal mucus is regulated by factors such as diet, living habits, hormones, neurotransmitters, cytokines, and intestinal flora. The mucus layer's thickness, viscosity, porosity, growth rate, and glycosylation status affect the structure of the gut flora colonized on it. The interaction between "mucus layer-soil" and "gut bacteria-seed" is an important factor leading to the pathogenesis of non-alcoholic fatty liver disease (NAFLD). Probiotics, prebiotics, fecal microbiota transplantation (FMT), and wash microbial transplantation are efficient methods for managing NAFLD, but their long-term efficacy is poor. FMT is focused on achieving the goal of treating diseases by enhancing the "gut bacteria-seed". However, a lack of effective repair and management of the "mucus layer-soil" may be a reason why "seeds" cannot be well colonized and grow in the host gut, as the thinning and destruction of the "mucus layer-soil" is an early symptom of NAFLD. This review summarizes the existing correlation between intestinal mucus and gut microbiota, as well as the pathogenesis of NAFLD, and proposes a new perspective that "mucus layer-soil" restoration combined with "gut bacteria-seed" FMT may be one of the most effective future strategies for enhancing the long-term efficacy of NAFLD treatment.

Integrated microbiota and metabolite profiling analysis of prebiotic characteristics of Phellinus linteus polysaccharide in vitro fermentation

Phellinus linteus polysaccharide (PLP) had received increasing attention due to its multiple biological activities. Herein, the extraction, characterization and in vitro fermentation of PLP were studied to explore its physiochemical properties and the interaction mechanism between the gut microbiota and PLP. The results obtained demonstrated that PLP was mainly composed of 9 monosaccharides, with three gel chromatographic peaks and molecular weights (M_w) of 308.45 kDa, 13.58 kD and 3.33 kDa, respectively. After 48 h fermentation, the M_w, total sugar, reducing sugar, pH and monosaccharides composition were decreased. Furthermore, PLP regulated the composition of gut microbiota, such as promoting the proliferation of beneficial bacteria such as Bacteroides, Prevotella and Butyricimonas, while preventing the growth of pathogenic bacteria such as Escherichia-Shigella, Morganella and Intestinimonas. Gut microbiota metabolites regulated by PLP such as short-chain fatty acids were the main regulators that impact the host health. Bioinformatics analysis indicated that butyrate, bile acid and purine metabolism were the main metabolic pathways of PLP regulating host health, and the Bacteroides was the key genus to regulate these metabolic pathways. In conclusion, our finding suggested that PLP may be used as a prebiotic agent for human health because of its ability to regulate gut microbiota.

The effects of pectin on the gut microbiota and serum metabolites in mice fed with a high fat diet and exposed to low-dose antibiotics

A sedentary lifestyle, unhealthy diet, and antibiotic use among other environmental factors have been associated with an increased incidence of metabolic disorders and inflammation, as well as gut dysbiosis. Pectin is an edible polysaccharide that exists widely in the cell wall of plants. Our previous study has shown that pectin with various degrees of esterification displayed different effects on preventing acute colitis and regulating the gut microbiome and serum metabolome. This study aimed to further explore the differential effects of pectin with various degrees of esterification on mice simultaneously treated with a high-fat diet and low-dose antibiotics. The results showed that low-esterified pectin L102 improved the biomarkers of metabolic disorders including blood glucose and body weight. The high-esterified pectin H121 and the low-esterified pectin L13 ameliorated inflammatory markers such as superoxide dismutase (SOD). The enrichment of probiotic bacteria such as Lactobacillus by pectin L102, reduction of conditional pathogens such as Klebsiella by pectin L13, and changes in circulating metabolites like L-tryptophan and 3-indoleacrylate by all three types of pectins were detected. These data provide evidence for a differential effect of different types of pectin on the gut microbiota and metabolic health.

Pu-erh tea alleviated colitis-mediated brain dysfunction by promoting butyric acid production

Brain inflammation develops with increased colitis. Pu-erh tea is considered a potential dietary intervention to improve colitis. However, it's unclear whether Pu-erh tea helps alleviate colitis-mediated brain dysfunction. Here, we found that colitis triggered brain dysfunction and increased the risk of depression. Pu-erh tea improved gut-brain barrier function (increased ZO-1 and Occludin) and restored short-chain fatty acids (SCFAs) as well as neurotransmitter release (γ-GABA, 5-HT, and dopamine), which stemmed from the production of butyric acid (BA). Pu-erh tea and BA promoted the production of SCFAs by reshaping the gut microbes (increased Lactobacillus, Akkermansia, Faecalibaculum), thereby downregulating gut inflammatory protein expression (PI3K/AKT/NF-κB). SCFAs, especially BA, intervened directly in the blood-brain barrier via the gut-brain axis to restore neurotransmitter release. Collectively, our results highlighted that increasing BA through Pu-erh tea consumption may be a key mechanism for improving colitis-mediated brain dysfunction by lowering gut inflammation and balancing gut microbe-gut-brain axis homeostasis. These results provide a promising step that might encourage further investigations of Pu-erh tea as a protective agent for brain function in colitis patients.

RGI-Type Pectic Polysaccharides Modulate Gut Microbiota in a Molecular Weight-Dependent Manner In Vitro

In this study, the fermentation characteristics of high rhamnogalacturonan I pectic polysaccharides (RGI) and free-radical degraded RGI (DRGI) were evaluated by a human fecal batch-fermentation model, and their structural properties were also investigated. As a result, the M_w of RGI decreased from 246.8 to 11.6 kDa, and the branches were broken dramatically. Fermentation showed that RGI degraded faster and produced more acetate and propionate than DRGI. Both of them reduced the Firmicutes/Bacteroidetes ratio and promoted the development of Bacteroides, Bifidobacterium, and Lactobacillus, bringing benefits to the gut ecosystem. However, the composition and metabolic pathways of the microbiota in RGI and DRGI were different. Most of the dominant bacteria of RGI (such as [Eubacterium]_eligens_group) participated in carbohydrate utilization, leading to better performance in glucolipid metabolism and energy metabolism. This work elucidated that large molecular weight matters in the gut microbiota modulatory effect of RGI-type pectic polysaccharides in vitro.

Crosstalk between imbalanced gut microbiota caused by antibiotic exposure and rotavirus replication in the intestine

Objective

Rotavirus (RV), one of non-enveloped double-strained RNA viruses, can cause infantile diarrheal illness. It is widely accepted that RV is transmitted mainly via feces-oral route. However, infected asymptomatic adults are becoming the source of infection. It is necessary to explore the underlying mechanism of RV replication in adult's intestine.

Methods

After recruiting healthy volunteers and RV asymptomatic carriers, we firstly investigated the association of animal-derived food intake with antibiotic level in urine samples. Secondly, we compared the difference in the structure of gut microbiota, and identified the taxa that most likely explained the difference. Finally, we investigated the impact of lipopolysaccharide (LPS), produced by gram-negative bacteria, on RV replication in vivo and in vitro.

Results

We found that 10% of participants were RV asymptomatic carriers in our study. High intake of animal-derived food was positively correlated to antibiotic level in urine samples. The disrupted gut microbiota in RV carriers was characterized by high abundance of antibiotic resistant gram-negative bacteria and high level of LPS. The disrupted gut microbiota caused by penicillin treatment was benefit to RV replication in vivo. LPS enhanced RV thermal stability in vitro.

Conclusions

Our findings suggest that the imbalanced gut microbiota caused by antibiotic exposure plays an important role in RV replication, and brings risk to health complications.

Preventive Effects of l-Glutamine on High-Fat Diet-Induced Metabolic Disorders Linking with Regulation of Intestinal Barrier Integrity, Hepatic Lipid Metabolism, and Gut Microbiota in Rats

The present study was conducted to investigate the effects of l-glutamine (Gln) on a high-fat diet (HFD)-induced lipid metabolic abnormality and explore its possible mechanisms. The results demonstrated that Gln administration reduced body weight, improved serum lipids, and decreased glucose tolerance in HFD-fed rats. Meanwhile, Gln administration alleviated liver injury, reduced the hepatic inflammatory response by inhibiting NLRP3 inflammasome activation, and decreased hepatic lipid accumulation by promoting VLDL secretion and fatty acid β-oxidation, as well as reduced bile acid synthesis by activating hepatic and ileal FXR in HFD-fed rats. Moreover, Gln administration restored HFD-induced intestinal barrier dysfunction, promoted intestinal fat absorption, suppressed intestinal inflammation, and also reshaped the gut microbiota composition in HFD-fed rats by downregulating the abundance of potential pathogens Escherichia-Shigella and upregulating the abundance of beneficial bacteria such as Akkermansia. To conclude, the present results showed that Gln may be a potential option for preventing HFD-induced metabolic disorders via the gut-liver axis.

Impact of gut microbiome on dyslipidemia in japanese adults: Assessment of the Shika-machi super preventive health examination results for causal inference

Dyslipidemia (DL) is one of the most common lifestyle-related diseases. There are few reports showing the causal relationship between gut microbiota (GM) and DL. In the present study, we used a linear non-Gaussian acyclic model (LiNGAM) to evaluate the causal relationship between GM and DL. A total of 79 men and 82 women aged 40 years or older living in Shika-machi, Ishikawa Prefecture, Japan were included in the analysis, and their clinical information was investigated. DNA extracted from the GM was processed to sequence the 16S rRNA gene using next-generation sequencing. Participants were divided into four groups based on sex and lipid profile information. The results of one-way analysis of covariance, linear discriminant analysis effect size, and least absolute value reduction and selection operator logistic regression model indicated that several bacteria between men and women may be associated with DL. The LiNGAM showed a presumed causal relationship between different bacteria and lipid profiles in men and women. In men, Prevotella 9 and Bacteroides were shown to be potentially associated with changes in low- and high-density lipoprotein cholesterol levels. In women, the LiNGAM results showed two bacteria, Akkermansia and Escherichia/Shigella, had a presumptive causal relationship with lipid profiles. These results may provide a new sex-based strategy to reduce the risk of developing DL and to treat DL through the regulation of the intestinal environment using specific GM.

Recent advances in lean NAFLD

As the predominant type of chronic liver disease, the growing prevalence of nonalcoholic fatty liver disease (NAFLD) has become a concern worldwide. Although obesity plays the most pivotal role in NAFLD, approximately 10-20% of individuals with NAFLD who are not overweight or obese (BMI < 25 kg/m2, or BMI < 23 kg/m2 in Asians) have "lean NAFLD." Lean individuals with NAFLD have a lower prevalence of diabetes, hypertension, hypertriglyceridemia, central obesity, and metabolic syndrome than nonlean individuals with NAFLD, but higher fibrosis scores and rates of cardiovascular morbidity and all-cause mortality in advanced stages. The pathophysiological mechanisms of lean NAFLD remain poorly understood. Studies have shown that lean NAFLD is more correlated with factors such as environmental, genetic susceptibility, and epigenetic regulation. This review will examine the way in which the research progress and characteristic of lean NAFLD, and explore the function of epigenetic modification to provide the basis for the clinical treatment and diagnosis of lean NAFLD.

Lifestyle Interventions for Non-Obese Patients Both with, and at Risk, of Non-Alcoholic Fatty Liver Disease

Non-alcoholic fatty liver disease occurring in non-obese subjects (the so-called non-obese NAFLD) is a highly prevalent but neglected liver condition, which is closely associated with metabolic disorders and suboptimal lifestyles. Landmark studies have shown that lifestyle interventions are potentially beneficial in decreasing the risk of developing non-obese NAFLD and in ameliorating NAFLD in non-obese individuals with pre-existing NAFLD. Lifestyle interventions usually refer to changes in eating habits and physical activity, both of which have a powerful effect on non-obese NAFLD and on risk factors for non-obese NAFLD. However, to date, patients and health-care professionals have a poor awareness and understanding of non-obese NAFLD and the beneficial effects of lifestyle interventions in this patient population. The aim of this narrative review is to briefly discuss the evidence for the effects of lifestyle changes and what changes are needed amongst medical personnel and other stakeholders in order to raise awareness of non-obese NAFLD.

Gut Microbiota Signature of Obese Adults Across Different Classifications

PURPOSE

Obesity is currently a major global public health issue. It has been shown by many that gut microbiota and microbial factors regulate the pathogenesis of obesity and metabolic abnormalities, but little is known about their roles in the different degrees of obesity. Here, we sought to investigate the microbial signatures of obesity of various severities.

PATIENTS AND METHODS

We did this by characterizing the intestinal microbiome signature in a Chinese cohort of obese patients and healthy controls using 16S rRNA gene sequencing. To this end, obesity was sub-divided into four subgroups, including "Overweight", Class I, Class II, and Class III obesity, based on body mass index (BMI).

RESULTS

Microbial diversity decreased in obese subjects, and the reduction trend was correlated with the severity of obesity. We detected an expansion of Escherichia shigella in obese patients compared to healthy controls. The family Eubacterium coprostanoligenes and Tannerellaceae, the genera Eubacterium coprostanoligenes, Lachnospiraceae NK4A136, Parabacteroides, and Akkermansia, and the species Prevotella copri were microbial biomarkers of healthy people. Gammaproteobacteria and Enterobacterales were biomarkers of being "Overweight". Erysipelatoclostridiaceae was a biomarker of Class I obesity. The class Bacilli and the order Lactobacillales were both biomarkers of Class II obesity. Negativicutes was a biomarker of Class III obesity. We further established relationships between this microbiome data and other biochemical data, including albumin, low-density lipoprotein (LDL), high-density lipoprotein (HDL), vitamin folic acid (FA) and vitamin B12 (VB12), and Interleukin-6 (IL-6) levels. Function prediction results showed a marked energy metabolism dysbiosis in obesity, especially in patients with Class III obesity.

CONCLUSION

These results suggested that people with different levels of obesity had distinct gut microbial signatures. Decreased microbial diversity, depletion of some specific taxa, and deviation in potential functions mirrored the severity of obesity in this cohort.