The Ruminococci: key symbionts of the gut ecosystem

Mechanistic Insights into Propolis in Targeting Type 2 Diabetes Mellitus: A Systematic Review

Type 2 diabetes mellitus (T2DM) is a major global health concern characterized by insulin resistance and impaired glucose metabolism. Growing interest in natural therapies has led to the exploration of propolis, a resinous bee product, for its potential anti-diabetic effects. This review examines the mechanisms by which propolis may aid in T2DM management. A literature search was conducted in SCOPUS and PubMed using the terms (Propolis) AND (diabetes OR "insulin resistance" OR hyperglycemia), focusing on studies published from 2014 onwards. The search yielded 384 and 207 records in SCOPUS and PubMed, respectively. After screening and full-text review, 42 studies met the inclusion criteria. Key variables analyzed included the type and source of propolis, experimental models, dosage, treatment duration, and primary and secondary outcomes. Findings highlight multiple mechanisms through which propolis may benefit T2DM, including enhancing pancreatic β-cell function, improving insulin sensitivity, regulating glucose and lipid metabolism, modulating gut microbiota, and reducing oxidative stress and inflammation. Some studies also reported protective effects on renal and hepatic function. Overall, propolis exhibits promising potential as a complementary therapy for T2DM. However, further well-designed clinical trials are necessary to confirm its efficacy, determine optimal dosing, and identify key bioactive compounds responsible for its therapeutic effects. Future research should focus on optimizing its clinical application for diabetes management.

Deciphering the influence of gut and oral microbiomes on menopause for healthy aging

Menopause is characterized by the cessation of menstruation and a decline in reproductive function, which is an intrinsic component of the aging process. However, it has been a frequently overlooked field of women's health. The oral and gut microbiota, constituting the largest ecosystem within the human body, are important for maintaining human health and notably contribute to the healthy aging of menopausal women. Therefore, a comprehensive review elucidating the impact of the gut and oral microbiota on menopause for healthy aging is of paramount importance. This paper presents the current understanding of the microbiome during menopause, with a particular focus on alterations in the oral and gut microbiota. Our study elucidates the complex interplay between the microbiome and sex hormone levels, explores microbial crosstalk dynamics, and investigates the associations between the microbiome and diseases linked to menopause. Additionally, this review explores the potential of microbiome-targeting therapies for managing menopause-related diseases. Given that menopause can last for approximately 30 years, gaining insights into how the microbiome and menopause interact could pave the way for innovative interventions, which may result in symptomatic relief from menopause and an increase in quality of life in women.

AI for rapid identification of major butyrate-producing bacteria in rhesus macaques (Macaca mulatta)

BACKGROUND

The gut microbiome plays a crucial role in health and disease, influencing digestion, metabolism, and immune function. Traditional microbiome analysis methods are often expensive, time-consuming, and require specialized expertise, limiting their practical application in clinical settings. Evolving artificial intelligence (AI) technologies present opportunities for developing alternative methods. However, the lack of transparency in these technologies limits the ability of clinicians to incorporate AI-driven diagnostic tools into their healthcare systems. The aim of this study was to investigate an AI approach that rapidly predicts different bacterial genera and bacterial groups, specifically butyrate producers, from digital images of fecal smears of rhesus macaques (Macaca mulatta). In addition, to improve transparency, we employed explainability analysis to uncover the image features influencing the model's predictions.

RESULTS

By integrating fecal image data with corresponding metagenomic sequencing information, the deep learning (DL) and machine learning (ML) algorithms successfully predicted 16 individual bacterial genera (area under the curve (AUC) > 0.7) among the 50 most abundant genera in rhesus macaques (Macaca mulatta). The model was successful in predicting functional groups, major butyrate producers (AUC 0.75) and a mixed group including fermenters and short-chain fatty acid (SCFA) producers (AUC 0.81). For both models of butyrate producers and mixed fermenters, the explainability experiments revealed no decline in the AUC when random noise was added to the images. Increased blurring led to a gradual decline in the AUC. The model's performance was robust against the impact of fecal shape from smearing, with a stable AUC maintained until patch 4 for all groups, as assessed through scrambling. No significant correlation was detected between the prediction probabilities and the total fecal weight used in the smear; r = 0.30 ± 0.3 (p > 0.1) and r = 0.04 ± 0.36 (p > 0.8) for the butyrate producers and mixed fermenters, respectively.

CONCLUSION

Our approach demonstrated the ability to predict a wide range of clinically relevant microbial genera and microbial groups in the gut microbiome based on digital images from a fecal smear. The models proved to be robust to the smearing method, random noise and the amount of fecal matter. This study introduces a rapid, non-invasive, and cost-effective method for microbiome profiling, with potential applications in veterinary diagnostics.

A Novel Frontier in Gut-Brain Axis Research: The Transplantation of Fecal Microbiota in Neurodegenerative Disorders

The gut-brain axis (GBA) represents a sophisticated bidirectional communication system connecting the central nervous system (CNS) and the gastrointestinal (GI) tract. This interplay occurs primarily through neuronal, immune, and metabolic pathways. Dysbiosis in gut microbiota has been associated with multiple neurodegenerative diseases, such as Parkinson's disease (PD), Alzheimer's disease (AD), multiple sclerosis (MS), and amyotrophic lateral sclerosis (ALS). In recent years, fecal microbiota transplantation (FMT) has gained attention as an innovative therapeutic approach, aiming to restore microbial balance in the gut while influencing neuroinflammatory and neurodegenerative pathways. This review explores the mechanisms by which FMT impacts the gut-brain axis. Key areas of focus include its ability to reduce neuroinflammation, strengthen gut barrier integrity, regulate neurotransmitter production, and reinstate microbial diversity. Both preclinical and clinical studies indicate that FMT can alleviate motor and cognitive deficits in PD and AD, lower neuroinflammatory markers in MS, and enhance respiratory and neuromuscular functions in ALS. Despite these findings, several challenges remain, including donor selection complexities, uncertainties about long-term safety, and inconsistencies in clinical outcomes. Innovations such as synthetic microbial communities, engineered probiotics, and AI-driven analysis of the microbiome hold the potential to improve the precision and effectiveness of FMT in managing neurodegenerative conditions. Although FMT presents considerable promise as a therapeutic development, its widespread application for neurodegenerative diseases requires thorough validation through well-designed, large-scale clinical trials. It is essential to establish standardized protocols, refine donor selection processes, and deepen our understanding of the molecular mechanisms behind its efficacy.

Elucidating Causal Relationships Among Gut Microbiota, Human Blood Metabolites, and Knee Osteoarthritis: Evidence from a Two-Stage Mendelian Randomization Analysis

Background: Although previous observational studies suggest a potential association between gut microbiota (GM) and knee osteoarthritis (KOA), the causal relationships remain unclear, particularly concerning the role of blood metabolites (BMs) as potential mediators. Elucidating these interactions is crucial for understanding the mechanisms underlying KOA progression and may inform the development of novel therapeutic strategies. Objective: This study aimed to determine the causal relationship between GM and KOA and to quantify the potential mediating role of BMs. Methods: Instrumental variables (IVs) for GM and BMs were retrieved from the MiBioGen consortium and metabolomics genome-wide association studies (GWAS) databases. KOA-associated single-nucleotide polymorphisms were sourced from the FinnGen consortium. Inverse-variance weighted approach was utilized as the main analytical method for Mendelian randomization (MR) analysis, complemented by MR-Egger, simple mode, weighted mode, and weighted median methods. The causal relationships between GM, BMs, and KOA were sequentially analyzed by multivariate MR. False discovery rate correction was applied to account for multiple comparisons in the MR results. Sensitivity analyses and reverse MR analysis were also conducted to verify the reliability of the findings. Finally, a two-step approach was employed to determine the proportion of BMs mediating the effects of GM on KOA. Results: MR analysis identified seven gut microbial species that are causally associated with KOA. Additionally, MR analysis of 1091 BMs and 309 metabolite ratios revealed 13 metabolites that influence the risk of KOA. Through two-step analysis, three BMs were identified as mediators of the effects of two GMs on KOA. Among them, 6-hydroxyindole sulfate exhibited the highest mediation percentage (10.26%), followed by N-formylanthranilic acid (6.55%). Sensitivity and reverse causality analyses further supported the robustness of these findings. Conclusion: This research identified specific GMs and BMs that have a causal association with KOA. These findings provide critical insights into how GM may influence KOA risk by modulating specific metabolites, which could be valuable for the targeted treatment and prevention of KOA.

Effects of dietary fiber on the composition, function, and symbiotic interactions of intestinal microbiota in pre-weaned calves

Introduction

Dietary fiber plays a crucial role in maintaining gastrointestinal health. However, its protective effects on the intestinal health of calves remain to be fully elucidated. This study aimed to investigate the impact of dietary fiber supplementation on the intestinal microbiota of pre-weaned calves and its potential role in modulating microbial metabolic pathways.

Methods

A randomized controlled trial was conducted, enrolling 135 calves that were randomly assigned into three groups: (1) inulin supplementation, (2) psyllium husk powder (PHP) supplementation, and (3) a control group receiving no dietary fiber. Fecal microbiota samples were collected from calves without diarrhea at five time points (0, 7, 14, 28, and 56 days of age). Metagenomic sequencing was performed to analyze microbial composition and functional pathways. Additionally, a differential analysis of carbohydrate-active enzymes (CAZymes) was performed to evaluate the effect of dietary fiber on carbohydrate metabolism enzyme activity within the intestinal microbiota.

Results

Calves supplemented with dietary fiber exhibited a significant increase in the abundance of Bifidobacterium and Prevotella compared to the control group. These bacterial genera contributed to intestinal protection by modulating secondary bile acid metabolism and flavonoid metabolism pathways. CAZymes differential analysis revealed an increased abundance of carbohydrate metabolism enzymes in response to dietary fiber supplementation, with distinct microbial community compositions observed among different fiber treatments. Notably, at 56 days of age, calves fed PHP harbored intergeneric symbiotic clusters comprising Clostridium, Prevotella, and Bacteroides, suggesting a cooperative microbial network that may contribute to intestinal homeostasis.

Discussion

The findings of this study highlight the beneficial effects of dietary fiber on calf intestinal microbiota, particularly in enhancing microbial diversity and enzymatic activity related to carbohydrate metabolism. The observed microbial symbiosis in PHP-fed calves suggests a potential role in maintaining intestinal homeostasis. These insights provide a theoretical foundation for optimizing dietary interventions to promote gut health in calves during the transition period. Further research is warranted to explore the mechanistic interactions between dietary fiber, gut microbiota, and host health outcomes.

Impact of Fermented Soy Beverages Containing Selected Vaginal Probiotics on the In Vitro Fecal Microbiota of Post-Menopausal Women

The gut microbiome of women can change after menopause, and during this phase women can also be more susceptible to vaginal dysbiosis. Recent studies have explored the probiotic potential of Lactobacillus crispatus BC4 and Lactobacillus gasseri BC9 against various pathogens and their use as co-starters in foods. However, their effects on the gut microbiota of post-menopausal women, who are more prone to dysbiosis, have not been examined. This study investigated the effects of predigested soy beverages (INFOGEST) containing BC4 and BC9 (encapsulated or not) on the composition and metabolic activity of the gut microbiota in post-menopausal women, using a fecal batch culture model. Parameters such as pH, gas, SCFAs, and microbiota composition (targeted qPCR and 16S rRNA gene sequencing) were assessed. The study, while highlighting a strong variability among donors, showed differences in gut microbiota response to the tested products. For instance, donor 2 showed a significant increase in bifidobacteria with BC4 + BC9 and E-BC9, while BC4 increased Ruminococcaceae in donors 1 and 3, and E-BC4 and E-BC9 enhanced Akkermansia in donor 1. BC4, E-BC4, E-BC9, and E-BC4 + BC9 significantly impacted metabolic activity, as measured by SCFAs, compared to other samples. However, no significant differences in gas production were observed.

Rumen microbiome associates with postpartum ketosis development in dairy cows: a prospective nested case-control study

BACKGROUND

Approximately, one-third of dairy cows suffer from postpartum diseases. Ketosis is considered an important inducer of other postpartum diseases by disrupting energy metabolism. Although the rumen microbiome may be involved in the etiology of ketosis by supplying volatile fatty acids, the rumen environmental dynamics of ketosis cows are unclear. Using multi-omics, this study aimed to elucidate changes in the rumen microbiome during parturition of ketosis cows and the association between the rumen microbiome and host energy metabolism. The study included 810 rumen content samples and 789 serum samples from day - 21 and 21 relative to calving day from 61 ketosis cows and 84 healthy cows.

RESULTS

In ketosis cows, the rumen bacterial composition after parturition changed dramatically and needed a longer time to restore. The molar proportions of propionate were lower in ketosis cows than those in healthy cows on days 3 and 7 and negatively correlated with the serum β-hydroxybutyrate (BHBA) levels. The fermentation sub-pathway of propionate metabolism and partial glucogenic amino acid pathways were downregulated on day 3. Prevotella, UBA1066, and microbiota diversity indices regulate serum BHBA and glucose (GLU) levels via arginine, alanine, glycine, or propionate. Propionate administration to ketosis cows potentially decreased the serum BHBA concentration.

CONCLUSIONS

Collectively, we found rumen disruption happened after calving among ketosis cows, and insufficient glycogenic substrates, such as propionate, may be related to ketosis development. The study findings have implications for the relationship between rumen microbiome dynamics and host energy metabolism, which lays the foundation for the future rumen microbiome investigation for improving postpartum management in cows. Video Abstract.

Multi-Omics Analysis Reveals the Negative Effects of High-Concentrate Diets on the Colonic Epithelium of Dumont Lambs

Feeding HC diets has been found to induce metabolic dysregulation in the colon. However, the mechanisms by which changes in colonic flora and metabolites damage the colonic epithelium are poorly studied. Therefore, the present experiment used a multi-omics technique to investigate the mechanism of colonic injury induced by high-concentrate diets in lambs. Twelve male Dumont lambs were randomly split into two groups: a low-concentrate diet (LC = concentrate/forage = 30:70) group and a high-concentrate diet (HC = concentrate/forage = 70:30) group. The results showed that the HC group presented significantly increased lipopolysaccharide (LPS) concentrations in the colonic epithelium and significantly decreased serum total cholesterol (TC), superoxide dismutase (SOD), and glutathione peroxidase (GSH-Px) levels (p < 0.05), which led to cavities and inflammatory cell infiltration in the colonic epithelium. The HC group had significantly lower pH and less VFAs in colon contents, as well as a significantly increased abundance of bacteria of the genera [Eubacterium]_coprostanoligenes_group, Rikenellaceae_RC9_gut_group, Treponema, Clostridia_UCG-014, Alistipes, Ruminococcus, Christensenellaceae_R-7_group, UCG-002, Bacteroidales_RF16_group and Lachnospiraceae_AC2044_group compared to the LC diet group. These microorganisms significantly increased the level of metabolites of cholic acid, chenodeoxycholic acid, LysoPA (P-16:0/0:0), methapyrilene, and fusaric acid. A transcriptome analysis showed that cytokine-cytokine receptor interaction, glutathione metabolism, and the peroxisome signaling pathway were downregulated in the colon epithelium of the lambs fed the HC diet. Therefore, the HC diet caused epithelial inflammation and oxidative damage by affecting the interaction between the microbial flora of the colon and metabolites and the host epithelium, which eventually disrupted colon homeostasis and had a negative impact on sheep health.

Ruminococcus gnavus in the gut: driver, contributor, or innocent bystander in steatotic liver disease?

The human gut microbiome plays a crucial role in regulating intestinal and systemic health, impacting host immune response and metabolic function. Dysbiosis of the gut microbiome is linked to various diseases, including steatotic liver diseases. Metabolic dysfunction-associated steatotic liver disease (MASLD), a chronic liver disease characterized by excess hepatic lipid content and impaired metabolism, is the leading cause of liver disease worldwide. Among the gut microbes, Ruminococcus gnavus (R. gnavus) has garnered attention for its association with inflammatory and metabolic diseases. While R. gnavus abundance correlates to liver fat accumulation, further research is needed to identify a causal role or therapeutic intervention in steatotic liver disease. This review surveys our current understanding of R. gnavus in the development and progression of steatotic liver diseases, highlighting its potential mechanisms through metabolite secretion, and emphasizes the need for comprehensive microbiome analyses and longitudinal studies to better understand R. gnavus' impact on liver health. This knowledge could pave the way for targeted interventions aimed at modulating gut microbiota to treat and prevent MASLD and its comorbidities.

Gut microbiota is associated with persistence of longer-term BNT162b2 vaccine immunogenicity

Introduction

BNT162b2 immunogenicity wanes with time and we investigated association between gut microbiota and longer-term immunogenicity.

Methods

This cohort study prospectively recruited adult BNT162b2 two-dose recipients from three vaccination centers in Hong Kong. Blood samples were collected at baseline and day 180 after first dose, and tested for neutralizing antibodies (NAb) against receptor-binding domain (RBD) of wild type SARS-CoV-2 virus using chemiluminescence immunoassay. Shotgun DNA metagenomic sequencing was performed to characterize baseline stool microbiome. Baseline metabolites were measured by gas and liquid chromatography-tandem mass spectrometry (GC-MS/MS and LC-MS/MS). Primary outcome was persistent high NAb response (defined as top 25% of NAb level) at day 180. Putative bacterial species and metabolic pathways were identified using linear discriminant analysis [LDA] effect size analysis. Multivariable logistic regression adjusting for clinical factors was used to derive adjusted odds ratio (aOR) of outcome with bacterial species and metabolites.

Results

Of 242 subjects (median age: 50.2 years [IQR:42.5-55.6]; male:85 [35.1%]), 61 (25.2%) were high-responders while 33 (13.6%) were extreme-high responders (defined as NAb≥200AU/mL). None had COVID-19 at end of study. Ruminococcus bicirculans (log10LDA score=3.65), Parasutterella excrementihominis (score=2.82) and Streptococcus salivarius (score=2.31) were enriched in high-responders, while Bacteroides thetaiotaomicron was enriched in low-responders (score=-3.70). On multivariable analysis, bacterial species (R. bicirculans-aOR: 1.87, 95% CI: 1.02-3.51; P. excrementihominis-aOR: 2.2, 95% CI: 1.18-4.18; S. salivarius-aOR: 2.09, 95% CI: 1.13-3.94) but not clinical factors associated with high response. R. bicirculans positively correlated with most metabolic pathways enriched in high-responders, including superpathway of L-cysteine biosynthesis (score=2.25) and L-isoleucine biosynthesis I pathway (score=2.16) known to benefit immune system. Baseline serum butyrate (aOR:10.00, 95% CI:1.81-107.2) and isoleucine (aOR:1.17, 95% CI:1.04-1.35) significantly associated with extreme-high vaccine response.

Conclusion

Certain gut bacterial species, metabolic pathways and metabolites associate with longer-term COVID-19 vaccine immunogenicity.

Causal relationship between gut microbiota and dental caries: A Mendelian randomization analysis

The onset of dental caries is associated with multiple factors, including oral microbiota, dietary sugars, the defensive mechanisms of saliva and teeth, oral hygiene practices, and socioeconomic factors. However, its relationship with the gut microbiota remains to be further explored. It remains crucial to establish a definitive causal link between the gut microbiota and the development of dental caries. This study aimed to investigate the causal relationship between gut microbiota and the risk of dental caries, focusing on identifying specific microbial communities potentially implicated in its pathogenesis. Gut microbiota data from genome-wide association studies (GWAS) conducted by the MiBioGen consortium were utilized as the exposure variable, with dental caries as the outcome variable. A Mendelian randomization (MR) approach was employed, leveraging comprehensive, publicly available GWAS summary data from European populations. The primary analytical method was the inverse variance weighted method, supplemented by additional techniques such as the weighted median model, MR-Egger, simple mode, and weighted mode, to ensure the robustness of the results. Heterogeneity was evaluated using Cochran Q test, and potential pleiotropy was assessed through MR-Egger regression. Sensitivity analyses were performed using the leave-one-out method to further validate the findings. The results revealed that a higher relative abundance of Christensenellaceae, FamilyXIII, Ruminococcaceae, and Senegalimassilia was associated with a reduced risk of dental caries. In contrast, a higher relative abundance of Erysipelotrichia, Erysipelotrichales, Pasteurellales, Erysipelotrichaceae, Pasteurellaceae, Methanobrevibacter, Roseburia, and Terrisporobacter was linked to an elevated risk of dental caries. This study provides compelling evidence for a causal relationship between gut microbiota and the development of dental caries, offering novel insights into the potential role of specific gut microbial communities in the pathogenesis of dental caries.

Different Efficacy of Five Soluble Dietary Fibers on Alleviating Loperamide-Induced Constipation in Mice: Influences of Different Structural Features

Different dietary fibers have distinct structures, leading to significant variations in their laxative effects. To explore how these structural differences impact constipation intervention, a 14-day study was conducted on loperamide-induced constipated mice using five dietary fibers: soluble dietary fiber from steamed sweet potato (SDF-S), oat β-glucan (OB), polydextrose (PD), arabinogalactan (AG), and inulin (IN). The results showed that four fibers, excluding PD, significantly improved gastrointestinal (GI) transit rate (p < 0.05), although PD had the highest fecal moisture, it was significantly different from the lowest IN (p < 0.05). AG and IN resulted in higher 6 h fecal weights compared to other fibers. SDF-S and OB were more effective in modulating serum levels of gastrointestinal hormones. The different monosaccharide compositions and glycosidic bonds of these fibers led to distinct changes in gut microbiota composition and SCFA profiles. Galactose and arabinose in AG were linked to increased abundance of Lachnospiraceae_UCG-006, Bacteroides, and Odoribacter, promoting butyrate fermentation, which is positively correlated with GI transit rate. Glucose in SDF-S, OB, and PD favored acetate fermentation positively correlated with fecal moisture. Fructose in IN encouraged the proliferation of Muribaculaceae_unclassified and Ruminococcus, associated with butyrate fermentation and increased 6 h stool weight, respectively. The β-glycosidic bonds in OB may lead to high butyrate production through the selective proliferation of Lachnospiraceae_unclassified. Minor components like fucose, rhamnose, and ribose were positively correlated with the abundance of Oscillospiraceae_unclassified, Anaerotignum, and Lachnospiraceae_unclassified. In conclusion, the unique monosaccharide compositions and glycosidic bond differences in dietary fibers selectively promote the proliferation of fiber-degrading and butyrate-producing bacteria, resulting in varied effects on constipation relief.

Human microbiota peptides: important roles in human health

Covering: 1974 to 2024Human microbiota consist of a diverse array of microorganisms, such as bacteria, Eukarya, archaea, and viruses, which populate various parts of the human body and live in a cooperatively beneficial relationship with the host. They play a crucial role in supporting the functional balance of the microbiome. The coevolutionary progression has led to the development of specialized metabolites that have the potential to substitute traditional antibiotics in combating global health challenges. Although there has been a lot of research on the human microbiota, there is a considerable lack of understanding regarding the wide range of peptides that these microbial populations produce. Particularly noteworthy are the antibiotics that are uniquely produced by the human microbiome, especially by bacteria, to protect against invasive infections. This review seeks to fill this knowledge gap by providing a thorough understanding of various peptides, along with their in-depth biological importance in terms of human disorders. Advancements in genomics and the understanding of molecular mechanisms that control the interactions between microbiota and hosts have made it easier to find peptides that come from the human microbiome. We hope that this review will serve as a basis for developing new therapeutic approaches and personalized healthcare strategies. Additionally, it emphasizes the significance of these microbiota in the field of natural product discovery and development.

Cordycepin improves liver fibrosis and the intestinal flora disturbance induced by 3,5-diethoxycarbonyl-1,4-dihydroxylidine in mice

BACKGROUND AND AIMS

Studies have shown that improving the intestinal flora can alleviate the progression of liver fibrosis. Cordycepin has shown potential anti-inflammatory and anti-fibrosis effects. In this study, we aimed to investigate the effects of cordycepin on liver fibrosis and how it affects the intestinal flora composition to determine a potentially effective therapeutic approach for liver fibrosis.

EXPERIMENTAL PROCEDURE

C57BL/6 mice were fed a special diet containing 3,5-diethoxycarbonyl-1,4-dihydroxylidine (DDC) to induce liver fibrosis. The histopathological changes in liver tissue and intestinal mucosa were determining via immunohistochemical staining. Serum transaminase levels were determined using biochemical test kits. Faecalibaculum samples were sequenced via 16S rRNA sequencing.

RESULTS

Cordycepin reduced DDC-induced liver collagen deposition, improved serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels, and reduced the levels of endothelial dysfunction markers vascular cell adhesion molecule 1 (VCAM) and thrombomodulin (TM). Our analysis of the intestinal flora composition showed that Dubosiella, Faecalibaculum, and Bifidobacterium were significantly increased in the cordycepin-treated group (P < 0.05). The Dubosiella level was significantly negatively correlated with TM and VCAM levels, and serum levels of ALT and AST (P < 0.05). After treatment with cordycepin, the microvilli length in the intestinal mucosa, the density of goblet cells, and the expressions of occludin and zonula occludens protein 1 (ZO-1) were significantly increased (P < 0.05).

CONCLUSION

We discovered that cordycepin improves liver fibrosis in vivo. We found that Dubosiella levels were considerably increased in the cordycepin-treated group and were significantly negatively correlated with liver sinusoidal endothelial damage.

Astragalus polysaccharide alleviates mastitis disrupted by Staphylococcus aureus infection by regulating gut microbiota and SCFAs metabolism

Polysaccharides, key bioactive compounds derived from Chinese herbs, are increasingly recognized for their therapeutic potential in modulating gut microbiota to treat various diseases. However, their efficacy in alleviating mammary inflammation and oxidative stress and protecting the blood-milk barrier (BMB) compromised by Staphylococcus aureus (S. au) infection remains uncertain. As evidence for the gut-mammary axis grows, identifying natural prebiotic components that affect this axis is crucial. This study reveals that Astragalus polysaccharide (APS), the primary active constituent of Astragalus, effectively mitigates S. au infection in murine mammary glands, suppresses inflammatory responses, reduces oxidative stress, and restores BMB integrity. The involvement of APS in modulating gut microbiota was substantiated through gut microbial depletion experiments and fecal microbiota transplantation (FMT). Notably, APS uniquely enriched Ruminococcus bromii (R. bromii) in the gut, facilitating the metabolism of short-chain fatty acids (SCFAs), particularly acetate and butyrate, which are pivotal to APS's protective effects. Collectively, these results propose a novel therapeutic approach for the treatment and prevention of S. au-induced mastitis, leveraging APS and R. bromii as prebiotics and probiotics, respectively.

Intestinal microbiota and high-risk antibiotic resistance genes in wild birds with varied ecological traits: Insights from opportunistic direct sampling in Tianjin, China

Within One Health framework, the dissemination of antibiotic resistance genes (ARGs) and pathogenic bacteria by wild birds has attracted increasing attention. In this study, gut samples of wild birds opportunistically collected in Tianjin, China, situated along the East Asian-Australasian Flyway, were used to ascertain the realistic distribution of bacteria and ARGs in their intestinal tracts. These birds have different dietary habits (herbivore, carnivore, and omnivore) and residency statuses (resident and migratory birds). Using 16S rRNA gene sequencing and qPCR, we analyzed microbial communities and the abundance of high-risk ARGs and mobile genetic elements (MGEs). Birds with distinct ecological traits exhibited significant variations in gut bacterial composition, yet similar microbial diversity. Shigella sp. emerged as the core intestinal pathogen, with a mean relative abundance 2.57 to 1466 times higher than that of other pathogenic bacteria, and its concentration correlated with the host's trophic level as indicated by the δ15N values. The distribution of ARGs and MGEs also varied with bird ecological traits. All 10 targeted high-risk ARGs were detected in carnivores or passage migrants, while migratory birds carried significantly greater abundance of intI1 than residents (p < 0.05). The potential of migratory birds to harbor and disseminate pathogenic bacteria and ARGs cannot be ignored. Network analysis revealed blaTEM-1 presence in multiple core microorganisms, positively associated with Clostridioides difficile, emphasizing its risk potential. Positive dfrA12-intI1 correlation across trophic levels suggests potential for intI1-mediated transmission. Our study underscores the high potential risk posed by wild birds in carrying ARGs and pathogenic microorganisms, emphasizing the importance of further research and surveillance in this field.

Inhalation of 2,2',5,5'-tetrachlorobiphenyl (PCB52) causes changes to the gut microbiome throughout the gastrointestinal tract

Polychlorinated biphenyls (PCBs), such as PCB52, are hazardous environmental contaminants present in indoor and outdoor environments. Oral PCB exposure affects the colon microbiome; however, it is unknown if inhalation of PCBs alters the intestinal microbiome. We hypothesize that sub-acute inhalation of PCB52 affects microbial communities depending on the location in the (GI) gastrointestinal tract and the local profiles of PCB52 and its metabolites present in the GI tract following mucociliary clearance and biliary or intestinal excretion. Sprague-Dawley rats were exposed via nose-only inhalation 4 h per day, 7 days per week, for 4 weeks to either filtered air or PCB52. After 28 days, differences in the microbiome and levels of PCB52 and its metabolites were characterized throughout the GI tract. PCB52 inhalation altered taxa abundances and predicted functions altered throughout the gut, with most alterations occurring in the large intestine. PCB52 and metabolite levels varied across the GI tract, resulting in differing PCB × microbiome networks. Thus, the presence of different levels of PCB52 and its metabolites in different parts of the GI tract has varying effects on the composition and predicted function of microbial communities. Future studies need to investigate whether these changes lead to adverse outcomes.

Chlorella and vegetable oil inclusion in diets for growing rabbits: effects on growth, digestibility, plasma metabolites, and caecal fermentations and microbiota

The inclusion of microalgae in livestock diets has been shown to enhance animal productivity, immune response, and meat quality. However, the role of chlorella (Chlorella vulgaris) in growing rabbit nutrition has been scarcely explored, with available studies focusing on low inclusion levels (<1%) and their effects on rabbit growth and immune response. This study evaluated the growth performance, nutrient digestibility, plasma metabolites, caecal fermentative activity, and caecal microbiota composition of growing rabbits fed diets with different inclusion levels of chlorella and crude fat. A total of 648 mixed-sex Grimaud crossbred rabbits (33 d of age; 841 ± 140 g live weight) were fed six experimental diets (96 rabbits per diet for the growth trial) based on a bifactorial design with three dietary inclusion levels of chlorella (0, 1, and 2%) and two levels of crude fat (3 and 5%) obtained by the inclusion of soybean oil (1 and 3%, respectively). The trial lasted 38 days until slaughter. From 47 to 51 days of age, 72 rabbits (12 per diet) were submitted to a digestibility trial. At 51 days of age, samples of plasma and caecal content were collected from 36 rabbits (six rabbits per diet) to analyse plasma metabolites, caecal fermentations, and caecal microbiota. Rabbit live weight at 71 days of age (2 700 g, on average), weight gain (48.8 g/d) and feed conversion ratio (3.27) were unaffected by chlorella inclusion, while feed conversion ratio improved (-5%; P < 0.001) with an increase of crude fat from 3 to 5%. The digestibility of ADF (23.2 vs 20.9%; P < 0.05) and crude fat (83.8 vs 85.6%; P < 0.01) improved with the inclusion of chlorella at 2%, as well as the digestibility of crude fat (82.4 vs 86.9%; P < 0.001) and gross energy (57.3 vs 58.7%; P < 0.001) with crude fat inclusion at 5%. Plasma non-esterified fatty acids decreased (-19%; P < 0.05) in diets with 5% crude fat. Neither chlorella nor crude fat inclusion levels affected other plasma metabolites, caecal fermentations, or caecal microbiota. Overall, the inclusion of chlorella up to 2% in diets for growing rabbits did not significantly affect diet nutritional value, animal performance, or caecal activity. On the other hand, increasing crude fat to 5% improved the overall feed efficiency.

Metabolism of quercitrin in the colon and its beneficial regulatory effects on gut microbiota

BACKGROUND

Quercitrin is a dietary flavonoid widely found in plants with various physiological activities. However, whether quercitrin alters gut microbiota in vivo is not well understood. The aim of this study was to investigate metabolism of quercitrin in the colon and its regulation on gut microbiota in mice.

RESULTS

Herein, 22 flavonoids related to quercitrin metabolism were identified based on ultra-performance liquid chromatography-electrospray ionization-tandem mass spectrometry (UPLC-ESI-MS/MS). Gas chromatography and 16S rDNA gene sequencing were used to investigate short-chain fatty acid (SCFA) content and diversity of composition of gut microbiota, respectively. The results showed that quercitrin significantly alters the beta-diversity of the gut microbiota, probiotics such as Akkermansia and Lactococcus were significantly increased, and the production of propanoate, isovalerate and hexanoate of the quercitrin group were enhanced significantly. The Spearman's association analysis provided evidence that Gardnerella and Akkermansia have obvious correlations with most of quercitrin metabolites and SCFAs.

CONCLUSION

Quercitrin and its metabolites in the colon altered the structure of the mice gut microbiota and increased the content of SCFAs. Our experiments provide valuable insights into quercitrin research and application. © 2024 Society of Chemical Industry.

Traditional Chinese medicine improved diabetic kidney disease through targeting gut microbiota

CONTEXT

Diabetic kidney disease (DKD) affects nearly 40% of diabetic patients, often leading to end-stage renal disease that requires renal replacement therapies, such as dialysis and transplantation. The gut microbiota, an integral aspect of human evolution, plays a crucial role in this condition. Traditional Chinese medicine (TCM) has shown promising outcomes in ameliorating DKD by addressing the gut microbiota.

OBJECTIVE

This review elucidates the modifications in gut microbiota observed in DKD and explores the impact of TCM interventions on correcting microbial dysregulation.

METHODS

We searched relevant articles from databases including Web of Science, PubMed, ScienceDirect, Wiley, and Springer Nature. The following keywords were used: diabetic kidney disease, diabetic nephropathy, gut microbiota, natural product, TCM, Chinese herbal medicine, and Chinese medicinal herbs. Rigorous criteria were applied to identify high-quality studies on TCM interventions against DKD.

RESULTS

Dysregulation of the gut microbiota, including Lactobacillus, Streptococcus, and Clostridium, has been observed in individuals with DKD. Key indicators of microbial dysregulation include increased uremic solutes and decreased short-chain fatty acids. Various TCM therapies, such as formulas, tablets, granules, capsules, and decoctions, exhibit unique advantages in regulating the disordered microbiota to treat DKD.

CONCLUSION

This review highlights the importance of targeting the gut-kidney axis to regulate microbial disorders, their metabolites, and associated signaling pathways in DKD. The Qing-Re-Xiao-Zheng formula, the Shenyan Kangfu tablet, the Huangkui capsule, and the Bekhogainsam decoction are potential candidates to address the gut-kidney axis. TCM interventions offer a significant therapeutic approach by targeting microbial dysregulation in patients with DKD.

In Silico Analysis of Probiotic Bacteria Changes Across COVID-19 Severity Stages

The gut microbiota plays a crucial role in modulating the immune response during COVID-19, with several studies reporting significant alterations in specific bacterial genera, including Akkermansia, Bacteroides, Bifidobacterium, Faecalibacterium, Lactobacillus, Oscillospira, and Ruminococcus. These genera are symbionts of the gut microbiota and contribute to host health. However, comparing results across studies is challenging due to differences in analysis methods and reference databases. We screened 16S rRNA raw datasets available in public databases on COVID-19, focusing on the V3-V4 region of the bacterial genome. In total, seven studies were included. All samples underwent the same bioinformatics pipeline, evaluating the differential abundance of these seven bacterial genera at each level of severity. The reanalysis identified significant changes in differential abundance. Bifidobacterium emerged as a potential biomarker of disease severity and a therapeutic target. Bacteroides presented a complex pattern, possibly related to disease-associated inflammation or opportunistic pathogen growth. Lactobacillus showed significant changes in abundance across the COVID-19 stages. On the other hand, Akkermansia and Faecalibacterium did not show significant differences, while Oscillospira and Ruminococcus produced statistically significant results but with limited relevance to COVID-19 severity. Our findings reveal new insights into the differential abundance of key bacterial genera in COVID-19, particularly Bifidobacterium and Bacteroides.

Microbiota alterations are related to migraine food triggers and inflammatory markers in chronic migraine patients with medication overuse headache

OBJECTIVE

Chronic migraine (CM) patients with medication overuse headache (MOH) were recently shown to be associated with leaky gut and inflammation. We aimed to investigate gut microbiota profiles of CM patients with MOH, and their correlations with inflammatory serum parameters, migraine food triggers, and comorbid anxiety and depression.

MATERIALS AND METHODS

The study included women participants (32 CM patients with NSAID overuse headache, and 16 healthy non-headache sufferers). Migraine duration, monthly migraine headache days, presence of irritable bowel syndrome symptoms, and HADS-D and HADS-A scores were recorded. Serum samples were collected to measure circulating LPS, HMGB1, HIF-1α, and IL-6. The gut microbiota profiles of the patients were evaluated using fecal samples.

RESULTS

Serum LPS, HMGB1, HIF-1α, and IL-6 levels were significantly higher in the CM + MOH group compared to the healthy controls. HADS-A and HADS-D scores were considerably higher in the CM + MOH group compared to the healthy controls. In the microbiota analysis, alpha and beta diversities were similar between the two groups. The class Clostridia, the order Eubacteriales, and the genus Ruminococcus were less abundant in the CM + NSAID overuse headache group compared to the control group. At the genus level Desulfovibrio, Gemmiger, and Dialister and at the species level, Clostridium fessum, Blautia luti, Dorea longicatena, Eubacterium coprostanoligenes, and Gemmiger formicilis were more abundant in the CM + NSAID overuse headache group compared to the control group. Desulfovibrio, Gemmiger, Dialister, Ethanoligenens harbinense, Eubacterium coprostanoligenes, Dorea longicatena, and Thermoclostridium stercorarium showed positive correlations and Clostridia bacteria showed negative correlations with migraine food triggers. Positive correlations were found between LPS and Hapalosiphonaceae, HMGB1 and Melghirimyces, HIF1-α and Rouxeilla and Blautia luti, IL-6 and Melghirimyces and Ruminococcus.

CONCLUSION

In CM patients with MOH, we have revealed the presence of dysbiosis towards an inflammatory state, and positive correlations were shown between altered gut microbiota and inflammatory serum parameters and migraine food triggers.

Blackcurrants shape gut microbiota profile and reduce risk of postmenopausal osteoporosis via the gut-bone axis: Evidence from a pilot randomized controlled trial

This study aimed to investigate the effects of blackcurrant (BC) on gut microbiota abundance and composition, inflammatory and immune responses, and their relationship with bone mass changes. The effects of BC on bone mineral density (BMD), gut microbiota, and blood inflammatory and immune biomarkers were evaluated using DXA, stool and fasting blood collected from a pilot three-arm, randomized, double-blind, placebo-controlled clinical trial. Fifty-one peri- and early postmenopausal women aged 45-60 years were randomly assigned into one of three treatment groups for 6 months: control, low BC (392 mg/day) and high BC (784 mg/day); and 40 women completed the trial. BC supplementation for 6 months effectively mitigated the loss of whole-body BMD (P<.05). Six-month changes (%) in peripheral IL-1β (P=.056) and RANKL (P=.052) for the high BC group were marginally significantly lower than the control group. Six-month changes in whole-body BMD were inversely correlated with changes in RANKL (P<.01). In proteome analysis, four plasma proteins showed increased expression in the high BC group: IGFBP4, tetranectin, fetuin-B, and vitamin K-dependent protein S. BC dose-dependently increased the relative abundance of Ruminococcus 2 (P<.05), one of six bacteria correlated with BMD changes in the high BC group (P<.05), suggesting it might be the key bacteria that drove bone protective effects. Daily BC consumption for 6 months mitigated bone loss in this population potentially through modulating the gut microbiota composition and suppressing osteoclastogenic cytokines. Larger-scale clinical trials on the potential benefits of BC and connection of Ruminococcus 2 with BMD maintenance in postmenopausal women are warranted. Trial Registration: NCT04431960, https://classic.clinicaltrials.gov/ct2/show/NCT04431960.

Gut microbiota, allergic rhinitis, vasomotor rhinitis, Mendelian randomization, causal association

OBJECTIVE

Continuous research on the structure and function of intestinal microecology has confirmed the association between gut microbiota and the occurrence, development, and outcome of allergic diseases. Here, we explored the genetic causality between gut microbiota and rhinitis.

METHODS

We conducted a two-sample Mendelian Randomization (MR) study to investigate the genetic causal relationship between gut microbiota and allergic rhinitis and vasomotor rhinitis. Genetic variations in the human gut microbiota were obtained from the summary statistics of the MiBioGen study. Genome-wide summary statistics of rhinitis were obtained from the FinnGen consortium. The causal effect between gut microbiota and rhinitis was assessed using the inverse variance weighted, MR-Egger regression, and weighted median methods. In addition, sensitivity analyses were conducted using different methods, including maximum likelihood, simple mode, and weighted model methods.

RESULTS

The IVW approach revealed a causal association of the genus Ruminococcus gauvreauii group with an increased risk of allergic rhinitis (IVW Odds Ratio [OR = 1.26] [1.04, 1.53], p-value = 0.01645). In addition, the genus Fusicatenibacter (IVW OR = 1.20 [1.02, 1.41], p-value = 0.02868) was causally associated with an increased risk of vasomotor rhinitis.

CONCLUSION

Gut microbiota belonging to different genera exert different effects on allergic rhinitis and vasomotor rhinitis, including reducing the risk of rhinitis, and increasing the risk of rhinitis. New insights into the mechanisms of underlying gut microbiota-associated rhinitis are provided.

LEVEL OF EVIDENCE

Level 5.

Negative energy balance affects perinatal ewe performance, rumen morphology, rumen flora structure, and placental function

This study investigated the effects of negative energy balance (NEB) on perinatal ewes, with a focus on changes in growth performance, serum biochemical parameters, rumen fermentation, ruminal bacteria composition, placental phenotype-related indicators, and expression levels of genes related to placental function. Twenty ewes at 130 days of gestation were randomly allocated to either the positive energy balance (PEB) or NEB groups. In the experiment, ewes in the PEB group were fed the same amount as their intake during the pre-feeding baseline period, while ewes in the NEB group were restricted to 70% of their individual baseline feed intake. The experiment was conducted until 42 days postpartum, and five double-lamb ewes per group were selected for slaughter. The results demonstrated that NEB led to a significant decrease in body weight, carcass weight, and the birth and weaning weights of lambs (P < 0.05). Additionally, NEB caused alterations in serum biochemical parameters, such as increased non-esterified fatty acids and β-hydroxybutyrate levels and decreased cholesterol and albumin levels (P < 0.05). Rumen fermentation and epithelial parameters were also affected, with a reduction in the concentrations of acetic acid, butyric acid, total acid and a decrease in the length of the rumen papilla (P < 0.05). Moreover, NEB induced changes in the structure and composition of ruminal bacteria, with significant differences in α-diversity indices and rumen microbial community composition (P < 0.05). Gene expression in rumen papilla and ewe placenta was also affected, impacting genes associated with glucose and amino acid transport, proliferation, apoptosis, and angiogenesis (P < 0.05). These findings screened the key microbiota in the rumen of ewes following NEB and highlighted the critical genes associated with rumen function. Furthermore, this study revealed the impact of NEB on placental function in ewes, providing a foundation for investigating how nutrition in ewes influences reproductive performance. This research demonstrates how nutrition regulates reproductive performance by considering the combined perspectives of rumen microbiota and placental function.

Liberated bioactive bound phenolics during in vitro gastrointestinal digestion and colonic fermentation boost the prebiotic effects of triticale insoluble dietary fiber

Phenolics in bound form extensively exist in cereal dietary fiber, especially insoluble fiber, while their release profile in gastrointestinal tract and contribution to the potential positive effects of dietary fiber in modulating gut microbiota still needs to be disclosed. In this work, the composition of bound phenolics (BPs) in triticale insoluble dietary fiber (TIDF) was studied, and in vitro gastrointestinal digestion as well as colonic fermentation were performed to investigate BPs liberation and their role in regulating intestinal flora of TIDF. It turned out that most BPs were unaccessible in digestion but partly released continuously during fermentation. 16 s rRNA sequencing demonstrated that TIDF possessed prebiotic effects by promoting anti-inflammatory while inhibiting proinflammatory bacteria alongside boosting SCFAs production and antioxidative BPs contributed a lot to these effects. Results indicated that TIDF held capabilities to regulate intestinal flora and BPs were important functional components to the health benefits of cereal dietary fiber.

Temporal changes in the mouse gut bacteriota influenced by host sex, diet, and exercise

The gut microbiota plays an important role in host physiology. However, the effects of host sex, lifestyle, and temporal influences on the bacterial community within the gut remain ill-defined. To address this gap, we evaluated 56 male and female mice over a 10-wk study to assess the effects of sex, diet, and exercise on gut community dynamics. Mice were randomly assigned to high-fat or control diet feeding and had free access to running wheels or remained sedentary throughout the study period. The fecal bacterial community was characterized by rRNA operon profiling via nanopore sequencing. Differential abundance testing indicated that ∼200 bacterial taxa were significantly influenced by sex, diet, or exercise (4.2% of total community), which also changed over time (82 taxa, 1.7% of total community). Phylogenetic analysis of taxa closely related to Dysosmobacter welbionis, and several members of the family Muribaculaceae were examined more closely and demonstrated distinct species/strain level subclustering by host sex, diet, and exercise. Collectively, these data suggest that sex and lifestyle can alter the gut bacteriota at the species/strain level that may play a role in host health. These results also highlight the need for improved characterization methods to survey microbial communities at finer taxonomic resolution.NEW & NOTEWORTHY This study demonstrates that host sex, diet, and exercise can each modulate gut bacterial community structure, which may have consequences to host physiology. Our analysis shows selection of novel strains and genera for some members of the Oscillospiraceae and Muribaculaceae by host sex, diet, and activity status. Overall, these findings provide a framework for detecting the next generation of beneficial bacteria targeting obesity and associated metabolic diseases in a sex-specific manner.

Enteromorpha prolifera Polysaccharide Alleviates Acute Alcoholic Liver Injury in C57 BL/6 Mice through the Gut-Liver Axis and NF-κB Pathway

Enteromorpha prolifera polysaccharide (EP2) protection against acute alcoholic liver injury (AALI) in mice was investigated. By integration of physiological indicators, gut microbiota, and short-chain fatty acids (SCFAs), the mechanism of EP2 in alleviating AALI was disclosed. The results showed that EP2 significantly ameliorated alcohol-induced abnormal transaminase activities, liver and intestinal systemic inflammation, and intestinal environmental disorders. EP2 significantly reduces liver and serum LPS contents by 1.69-fold and 1.54-fold. Furthermore, inhibition of the NF-κB signaling pathway by EP2 reduced the production of proinflammatory cytokines such as TNF-α (1.83-fold), IL-6 (11.09-fold), and IL-1β (1.99-fold). EP2 restored SCFAs to normal levels by upregulating the abundance of beneficial bacteria (Colidextribacter, Ruminococcus, unclassified_Lachnospiraceae, and Akkermansia). The alleviation of AALI by EP2 occurs through protection of the intestinal mucosal barrier and reduction of LPS permeating in serum. The decrease in LPS inactivates the NF-κB signaling pathway and prevents inflammation. In short, EP2 regulates the gut-liver axis and inflammation, alleviating effects in AALI mice.

A Systematic Review of the Effect of Polyphenols on Alterations of the Intestinal Microbiota and Shared Bacterial Profiles Between Metabolic Syndrome and Acne

Introduction: Microbiota, composed of micro-organisms like bacteria, viruses, and non-pathogenic fungi, plays a crucial role in digestion, vitamin production, and protection against dangerous microbes. Several factors, including age, diet, alcohol consumption, stress, environmental microorganisms, and therapies (particularly antibiotics), as well as birth and nursing, could modify the microbiota. Recent research has highlighted its alteration and involvement in a various disease, including metabolic syndrome and acne. This systematic review aimed to identify common biomarkers and microbiota alterations shared between metabolic syndrome and acne, and to explore how the potential prebiotic activities of polyphenols may promote intestinal eubiosis. Materials and methods: A comprehensive search in PubMed and EMBASE resulted in 4142 articles, from which nine studies were selected based on specific criteria after removing duplicates and reviewing abstracts and full texts. All studies correlated the microbiota alteration in both pathologies and the activity of polyphenols in metabolic syndrome. Results: This review suggests that acne may be influenced by some of the same microorganisms involved in metabolic syndrome. While the literature highlights the effectiveness of polyphenols in treating metabolic syndrome, no studies have yet demonstrated their specific impact on acne. Conclusions: The research points to the potential benefits of polyphenols in modulating the microbiota, which could be relevant for individuals with metabolic syndrome. However, due to the limited data available, it was not possible to establish a direct correlation between metabolic syndrome and acne.

Differential immunological responses in lamb rumen and colon to alfalfa hay and wheat straw in a concentrate-rich diet: insights into microbe-host interactions

The impact of a concentrate-rich (CR) diet on the gut microbiome and epithelium homeostasis is well documented. However, it has not been systematically studied whether and how host-microbial interaction contributes to the immune homeostasis in the rumen and colon of lambs fed alfalfa hay and wheat straw, alone or combined, in a CR diet. In all, 63 lambs (initial body weight, 16.69 ± 1.50 kg) were randomly allotted to three dietary groups, each consisting of three pens with seven lambs per pen. Over 14 weeks, the lambs were fed diets as follows: 60% concentrate supplemented with either 40% wheat straw (WG), 20% alfalfa hay combined with 20% wheat straw (MG), or 40% alfalfa hay (AG). The present findings showed that lambs in the AG group had greater (P < 0.05) IgG and lower (P = 0.067) tumor necrosis factor-alpha concentrations relative to those in the MG and WG groups. The 16S rRNA analysis highlighted that various bacterial phyla and genera in the rumen and colon preferentially degrade fiber and starch derived from alfalfa hay and wheat straw. The weighted gene co-expression network analysis revealed that the bacterial genera from the Firmicutes are broadly associated with genes involved in various signaling pathways, underscoring the potential role of Firmicutes as key drivers of host-microbial interactions under the present feeding conditions. These findings shed light on the fact that the rumen and colon immune homeostasis is distinctively influenced by diets of alfalfa hay, wheat straw, or their combination in a CR diet. Further studies should examine the prolonged effects of replacing wheat straw with alfalfa hay in a concentrate-rich diet formulated to provide equivalent neutral detergent fiber levels. This could reveal how various forage fibers influence host-microbial interactions and gut health.IMPORTANCEIn contemporary feedlots, a growing trend is to feed animals a concentrate-rich (CR) diet that could disrupt the synchronized interplay between microbes and host metabolism, leading to altered metabolic functions. Wheat straw and alfalfa hay have different levels of protein and neutral detergent fiber, each with varying rates of digestion. It is unclear how including alfalfa hay and wheat straw, alone or combined in a CR diet, influences the host-microbial consortia and immune homeostasis. Herein, we showed that rumen and colon showed differential immune responses to the alfalfa hay, wheat straw, or both. Bacterial genera preferentially degrade fiber and starch derived from alfalfa hay, wheat straw, or both. Bacterial genera from Firmicutes phylum play a pivotal role in driving the host-microbial interactions, as indicated by their extensive association with genes across various signaling pathways.

Gut Microbial Communities Are Seasonally Variable in Warm-Climate Lizards Hibernating in the Winter Months

Hibernation is an energy-saving and adaptive strategy adopted by a diverse array of animals, rarely including warm-climate species, to survive in the harsh winter environment. Here, we collected large-intestinal microbial samples from two species of warm-climate lizards, one (the Reeves' butterfly lizard Leiolepis reevesii) hibernating in the winter months and one (the many-lined sun skink Eutropis multifasciata) not doing so, in summer and winter to analyze and compare their microbiota using 16S rRNA gene amplicon sequencing technology. Gut microbiota were seasonally variable in L. reevesii but not in E. multifasciata. The decreased Firmicutes/Bacteroidetes ratio and increased relative abundance of Verrucomicrobia in hibernating butterfly lizards in a state of long-term fasting should help them live through the winter months, as bacteria of the phyla Bacteroidetes and Verrucomicrobia can use host-derived mucin glycans in the absence of dietary substrates. Facultative plant feeding by omnivorous butterfly lizards resulted in a significant increase in the relative abundance of bacteria of the phylum Firmicutes (e.g., Lachnospiraceae) with the ability to degrade plant fibers. This study not only validates the role of gut microbiota in dietary adaptation in lizards but also shows that gut microbial communities are seasonally variable in warm-climate lizards hibernating in the winter months.

Hawthorn pectin plays a protective role in myocardial ischaemia by regulating intestinal flora and short chain fatty acids

Studies have shown that there is a close relationship between acute myocardial ischaemia (AMI) and intestinal flora imbalance. And pectin has a protective effect on AMI and regulates intestinal flora. Raw hawthorn pectin from hawthorn (RHP) is high methoxyl pectin, which is able to protect injury induced by AMI. After stir-frying of hawthorn, pectin from stir-fried hawthorn (FHP) transformed to low methoxyl pectin, the protective mechanisms against AMI is not well-understood. In this study, the protective effects of RHP and FHP against AMI rats were explored. The results revealed that FHP regulated myocardial enzymes including CK, CK-MB and CTn-1, oxidative stress-related indicator SOD more significantly than RHP. According to the determination of proportion of different kinds of short-chain fatty acids (SCFAs) and abundance of microbiota producing SCFAs, it was speculated that RHP and FHP were fermented by these microbiota. RHP increased the proportion of acetic acid and butyric acid, while FHP increased the proportion of acetic acid in feces. Pretreatment with RHP and FHP enriched the beneficial microbiota and maintained the levels of SCFAs, which significantly increased after modeling. These results revealed that RHP and FHP played a protective role in myocardial ischaemia by regulating intestinal flora and SCFAs.

The Ruminal Microbiome Alterations Associated with Diet-Induced Milk Fat Depression and Milk Fat Globule Size Reduction in Dairy Goats

The aim of this study was to evaluate the effect of conjugated linoleic acid (CLA) on milk fat globule (MFG) size and the ruminal microbiome of goats. Twenty-four mid-lactation Saanen dairy goats weighing 49 ± 4.5 kg (168 ± 27 d in milk, 1.2 ± 0.1 kg milk/d, 2-3 years old) were randomly divided into four groups-a control (CON) group, which was fed a basal diet, and three CLA supplementation groups, in which 30 g CLA (low-dose group, L-CLA), 60 g CLA (medium-dose group, M-CLA), or 90 g CLA (high-dose group, H-CLA) was added to the basal diet daily. The experiment lasted for 21 days, during which time goat milk was collected for composition and MFG size analysis. On day 21 of feeding, ruminal fluid was collected from the CON and H-CLA groups for analysis of the changes in microorganismal abundance. The results showed that CLA supplementation did not affect milk production, milk protein, or lactose content in the dairy goats (p > 0.05), but significantly reduced the milk fat content (p < 0.01) compared with the CON group. The CLA supplementation significantly decreased the D[3,2] and D[4,3] of the MFGs in a dose-dependent manner (p < 0.01). Moreover, dietary CLA inclusion increased the proportion of small-sized MFGs and decreased that of large-sized ones. The results of 16S rRNA gene sequencing showed that CLA-induced milk fat depression in dairy goats was accompanied by significant changes in the relative abundance of ruminal bacterial populations, most of which belonged to the Firmicutes and Bacteroidetes phyla. The relative abundance of Rikenellaceae_RC9_gut_group and Prevolellaceae_UCG-003 in Bacteroidetes and UCG-002, Succiniclasticum, and norank_f__norank_o__Clostridia_vadinBB60_group in Firmicutes was significantly higher in the CON group than in the H-CLA group. In contrast, the relative abundance of norank_f__UCG-011, norank_f_Eubacterium_coprostanoligenes_group, unclassified_f__Lachnospiraceae, and UCG-001 in Firmicutes and norank_f__Muribaculaceae in Bacteroidetes was significantly higher in the H-CLA group than in the CON group. Correlation analysis showed that the milk fat content was negatively correlated with the relative abundance of some bacteria, including members of Firmicutes and Bacteroidetes. Similarly, MFG size (D[3,2] and D[4,3]) was negatively correlated with several members of Firmicutes and Bacteroidetes, including Lachnospiraceae, norank_f__UCG-011, UCG-001, norank_f__Eubacterium_coprostanoligenes_group (Firmicutes), and norank_f__Muribaculaceae (Bacteroidetes), while positively correlated with the relative abundance of some members of Firmicutes and Bacteroidetes, including Mycoplasma, Succiniclasticum, norank_f__norank_o__Clostridia_vadinBB60_group, UCG-002 (Firmicutes), and Rikenellaceae_RC9_gut_group (Bacteroidetes). Overall, our data indicated that CLA treatment affected milk fat content and MFG size in dairy goats, and these effects were correlated with the relative abundance of ruminal bacterial populations. These results provide the first evidence to explain the mechanism underlying diet-induced MFG from the perspective of the ruminal microbiome in dairy goats.

Hong Guo Ginseng Guo (HGGG) protects against kidney injury in diabetic nephropathy by inhibiting NLRP3 inflammasome and regulating intestinal flora

BACKGROUND

Diabetic nephropathy (DN) is one of the most serious complications of diabetes which leads to end-stage renal failure and approximately one-third of patients need dialysis. There is still a lack of effective and specific treatment for DN. Searching new drugs from natural foods is an alternative approach to treat diabetes and its complications. Hong Guo Ginseng Guo (HGGG), a berry with palatability and nutritional benefits, has exhibited medicinal properties to mitigate the progression of DN.

PURPOSE

This study investigates the effects of HGGG on streptozotocin (STZ)-induced diabetic nephropathy (DN) in rats and elucidates the mechanisms underlying its reno-protective and diabetes management benefits.

METHODS

The LC-MS spectra method identified the primary ingredients in HGGG. To induce DN, male Sprague-Dawley (SD) rats received a single intraperitoneal injection of 75 mg/kg STZ. Over an eight-week treatment period, we assessed biochemical parameters including blood glucose, urine albumin-to-creatinine ratio (UACR), blood urea nitrogen (BUN), and urine N-acetyl-beta-d-glucosaminidase (NAG). Tissue pathology was examined using Masson's trichrome, Periodic Acid-Schiff (PAS), and Hematoxylin-Eosin (H&E) stains. We analyzed pro-inflammatory mediators and tissue fibrosis extent using Western blotting and immunohistochemistry. Gut microbiota composition was characterized via 16S rDNA sequencing.

RESULTS

Seventeen chemical compounds were identified, with lobetyolin, luteolin, and rutin highlighted as the primary active elements. HGGG extract appeared to confer renal protection, demonstrated by improvements in UACR, BUN, and urine NAG levels. The reno protective effects in HGGG-treated DN rats were linked to reduced renal fibrosis and inhibition of the NLRP3 inflammasome. Additionally, HGGG administration improved gut barrier integrity and altered the gut microbiota in DN rats, increasing the relative abundance of beneficial bacteria known for regulating polyamines and producing short-chain fatty acids (SCFAs), including Ruminococcus, Barnesiella_sp, Anaerovoracaceae, and Prevotellaceae_NK3B31. Meanwhile, treatment with HGGG decreasing the presence of Oscillospira, potential pathogens responsible for producing lipopolysaccharide (LPS).

CONCLUSION

HGGG has potential as a beneficial fruit for managing diabetes and its associated complications through modulation of the gut microbiota.

Association of gut microbiome and oral cavity cancer: A two sample mendelian randomization and case-control study

INTRODUCTION

Considering the interconnectedness of the oral cavity and gut tract and the presence of abundant natural microbiota in both. We utilized Mendelian Randomization (MR) in a two-sample study to unveil the genetic causal impact of gut microbiota on the development of oral cavity cancer.

MATERIALS & METHODS

The instrumental variables employed in this study consisted of single nucleotide polymorphisms (SNPs) that demonstrated a robust association with 211 distinct gut microbiota taxa, encompassing a sample size of 18,340 individuals. Our investigation sought to explore the potential causal relationship between these genetic variants and the incidence of oral cavity cancer. To accomplish this, we adopted a random effect inverse variance-weighted approach to analyze the causal effect. Additionally, sensitivity analyses were performed utilizing Cochran's Q tests, funnel plots, leave-one-out analyses, and MR-Egger intercept tests, to assess the robustness and validity of our findings.

RESULTS

Five gut microbiota taxa (the family Prevotellaceae, the genus Alloprevotella, the genus Erysipelatoclostridium, the genus Parabacteroides, the genus Ruminococcus gauvreauii group) are predicted to play a causal role in promoting the initiation of the risk of oral cavity cancer. While the genus Christensenellaceae R 7 group, the genus Intestinimonas, the genus Ruminococcaceae, and the order Bacillales causally reduce the risk of oral cavity cancer. Furthermore, no significant evidence suggesting heterogeneity or pleiotropy was observed.

DISCUSSION

The novel genetic causal effects of 211 gut microbiota taxa on oral cavity cancer are elucidated in this investigation, thus offering valuable insights for clinical interventions targeting oral cavity cancer.

Natural Foraging Selection and Gut Microecology of Two Subterranean Rodents from the Eurasian Steppe in China

As the most abundant group of mammals, rodents possess a very rich ecotype, which makes them ideal for studying the relationship between diet and host gut microecology. Zokors are specialized herbivorous rodents adapted to living underground. Unlike more generalized herbivorous rodents, they feed on the underground parts of grassland plants. There are two species of the genus Myospalax in the Eurasian steppes in China: one is Myospalax psilurus, which inhabits meadow grasslands and forest edge areas, and the other is M. aspalax, which inhabits typical grassland areas. How are the dietary choices of the two species adapted to long-term subterranean life, and what is the relationship of this diet with gut microbes? Are there unique indicator genera for their gut microbial communities? Relevant factors, such as the ability of both species to degrade cellulose, are not yet clear. In this study, we analyzed the gut bacterial communities and diet compositions of two species of zokors using 16S amplicon technology combined with macro-barcoding technology. We found that the diversity of gut microbial bacterial communities in M. psilurus was significantly higher than that in M. aspalax, and that the two species of zokors possessed different gut bacterial indicator genera. Differences in the feeding habits of the two species of zokors stem from food composition rather than diversity. Based on the results of Mantel analyses, the gut bacterial community of M. aspalax showed a significant positive correlation with the creeping-rooted type food, and there was a complementary relationship between the axis root-type-food- and the rhizome-type-food-dominated (containing bulb types and tuberous root types) food groups. Functional prediction based on KEGG found that M. psilurus possessed a stronger degradation ability in the same cellulose degradation pathway. Neutral modeling results show that the gut flora of the M. psilurus has a wider ecological niche compared to that of the M. aspalax. This provides a new perspective for understanding how rodents living underground in grassland areas respond to changes in food conditions.

Survey of the fecal microbiota of indigenous small ruminants living in different areas of Guizhou

Introduction

Gut microbiota are associated with the health and performance of ruminant species, and they are affected by altitude, host genetics, and sex. However, there has been little research on comparing the fecal microbiota of indigenous small ruminants such as sheep and goats in Guizhou province, China. In the present study, we revealed the effect of altitude, genetics, and sex on fecal microbiota profiles and enterotypes in indigenous small ruminants of Guizhou province, China.

Methods

Fecal samples were collected from Hei and Qianbei Ma goats and Weining sheep in the Chinese province of Guizhou. 16S rRNA gene sequencing targeting the V3-V4 region was performed using the Illumina MiSeq platform. Sequences were processed using QIIME2, and the qualified sequences were processed using the plugin DADA2 to generate amplicon sequence variants (ASVs). The statistical analysis was performed using R studio.

Results

The fecal microbial profile was found to vary by herd (influenced by genetics/altitude) and sex. All samples were categorized into two enterotypes. The first enterotype is dominated by UCG-005, and the second enterotype is dominated by the Christensenellaceae_R-7_group, which may be highly driven by the host's genetics (breed). The predicted functional profiles of the fecal microbiota were also assigned to two clusters that corresponded exactly to the enterotypes. Cluster 1 of the functional profiling was characterized by biosynthesis pathways, and cluster 2 was characterized by energy metabolism pathways.

Discussion

Our findings may provide new insights into the fecal microbial community and enterotypes in small ruminants by herds, offering clues for understanding the mechanisms by which the fecal microbiota contribute to divergent host phenotypes in indigenous small ruminants in Guizhou.

Diverse mechanisms by which chemical pollutant exposure alters gut microbiota metabolism and inflammation

The human gut microbiome, the host, and the environment are inextricably linked across the life course with significant health impacts. Consisting of trillions of bacteria, fungi, viruses, and other micro-organisms, microbiota living within our gut are particularly dynamic and responsible for digestion and metabolism of diverse classes of ingested chemical pollutants. Exposure to chemical pollutants not only in early life but throughout growth and into adulthood can alter human hosts' ability to absorb and metabolize xenobiotics, nutrients, and other components critical to health and longevity. Inflammation is a common mechanism underlying multiple environmentally related chronic conditions, including cardiovascular disease, multiple cancer types, and mental health. While growing research supports complex interactions between pollutants and the gut microbiome, significant gaps exist. Few reviews provide descriptions of the complex mechanisms by which chemical pollutants interact with the host microbiome through either direct or indirect pathways to alter disease risk, with a particular focus on inflammatory pathways. This review focuses on examples of several classes of pollutants commonly ingested by humans, including (i) heavy metals, (ii) persistent organic pollutants (POPs), and (iii) nitrates. Digestive enzymes and gut microbes are the first line of absorption and metabolism of these chemicals, and gut microbes have been shown to alter compounds from a less to more toxic state influencing subsequent distribution and excretion. In addition, chemical pollutants may interact with or alter the selection of more harmful and less commensal microbiota, leading to gut dysbiosis, and changes in receptor-mediated signaling pathways that alter the integrity and function of the gut intestinal tract. Arsenic, cadmium, and lead (heavy metals), influence the microbiome directly by altering different classes of bacteria, and subsequently driving inflammation through metabolite production and different signaling pathways (LPS/TLR4 or proteoglycan/TLR2 pathways). POPs can alter gut microbial composition either directly or indirectly depending on their ability to activate key signaling pathways within the intestine (e.g., PCB-126 and AHR). Nitrates and nitrites' effect on the gut and host may depend on their ability to be transformed to secondary and tertiary metabolites by gut bacteria. Future research should continue to support foundational research both in vitro, in vivo, and longitudinal population-based research to better identify opportunities for prevention, gain additional mechanistic insights into the complex interactions between environmental pollutants and the microbiome and support additional translational science.

Changes in the Human Gut Microbiome Caused by the Short-Term Impact of Lactic Acid Bacteria Consumption in Healthy People

The gut microbiome is one of the main factors affecting human health. It has been proven that probiotics can regulate the metabolism in the host body. A large number of people use probiotics not as medicines, but as a prophylactic supplement. The aim of our study was to evaluate the effect of lactic acid bacteria on the gut microbiome of healthy people using the V3 region of the 16S rRNA gene. Our study showed changes in the generic composition in the gut of healthy people when taking the supplement. There was an increase in the members responsible for the production of short-chain fatty acids in the gut of the host (Blautia, Fusicatenibacter, Eubacterium hallii group, Ruminococcus), as well as bacteria that improve intestinal homeostasis (Dorea and Barnesiella). There was also a decrease in the abundance of bacteria in the genera Catenibacterium, Hungatella, Escherichia-Shigella, and Pseudomonas, associated with an unhealthy profile of the human gut microbiome. An increase in members of the phylum Actinobacteriota was also observed, which has a positive effect on the host organism. Our results indicate that short-term prophylactic use of lactic acid bacteria-based supplements can be effective, as it contributes to a beneficial effect on the gut microbiome of healthy people.

Assessing the impact of hatching system and body weight on the growth performance, caecal short-chain fatty acids, and microbiota composition and functionality in broilers

BACKGROUND

Variations in body weight (BW) remain a significant challenge within broiler flocks, despite uniform management practices. Chicken growth traits are influenced by gut microbiota, which are in turn shaped by early-life events like different hatching environments and timing of first feeding. Chicks hatched in hatcheries (HH) experience prolonged feed deprivation, which could adversely impact early microbiota colonization. Conversely, hatching on-farm (HOF) allows early feeding, potentially fostering a more favorable gut environment for beneficial microbial establishment. This study investigates whether BW differences among broilers are linked to the disparities in gut microbiota characteristics and whether hatching systems (HS) impact the initial microbial colonization of broilers differing in BW, which in turn affects their growth patterns. Male Ross-308 chicks, either hatched in a hatchery or on-farm, were categorized into low (LBW) and high (HBW) BW groups on day 7, making a two-factorial design (HS × BW). Production parameters were recorded periodically. On days 7, 14, and 38, cecal volatile fatty acid (VFA) and microbiota composition and function (using 16 S rRNA gene sequencing and PICRUSt2) were examined.

RESULTS

HOF chicks had higher day 1 BW, but HH chicks caught up within first week, with no further HS-related performance differences. The HBW chicks remained heavier attributed to higher feed intake rather than improved feed efficiency. HBW group had higher acetate concentration on day 14, while LBW group exhibited higher isocaproate on day 7 and isobutyrate on days 14 and 38. Microbiota analyses revealed diversity and composition were primarily influenced by BW than by HS, with HS having minimal impact on BW-related microbiota. The HBW group on various growth stages was enriched in VFA-producing bacteria like unclassified Lachnospiraceae, Alistipes and Faecalibacterium, while the LBW group had higher abundances of Lactobacillus, Akkermansia and Escherichia-Shigella. HBW microbiota presented higher predicted functional potential compared to the LBW group, with early colonizers exhibiting greater metabolic activity than late colonizers.

CONCLUSIONS

Despite differences in hatching conditions, the effects of HS on broiler performance were transient, and barely impacting BW-related microbiota. BW variations among broilers are likely linked to differences in feed intake, VFA profiles, and distinct microbiota compositions and functions.

The Influence of Increasing Roughage Content in the Diet on the Growth Performance and Intestinal Flora of Jinwu and Duroc × Landrace × Yorkshire Pigs

The Jinwu pig (JW) is a hybrid breed originating from the Chinese indigenous Jinhua pig and Duroc pig, boasting excellent meat quality and fast growth rates. This study aimed to verify the tolerance of JW to roughage, similar to most Chinese indigenous pigs. In this research, two types of feed were provided to JW and Duroc × Landrace × Yorkshire pigs (DLY): a basal diet and a roughage diet (increasing the rice bran and wheat bran content in the basal diet from 23% to 40%) for a 65-day experimental period. The roughage diet showed an increasing trend in the feed conversion ratio (F/G), with a 17.61% increase in feed consumption per unit weight gain for DLY, while the increase for JW was only 4.26%. A 16S rRNA sequencing analysis revealed that the roughage diet increased the relative abundance of beneficial bacteria, such as Lactobacillus and Clostridium, while reducing the relative abundance of some potential pathogens, thus improving the gut microbiota environment. After being fed with the roughage diet, the abundance of bacterial genera, such as Treponema, Terrisporobacter, Coprococcus, and Ruminococcaceae, which aid in the digestion and utilization of dietary fiber, were significantly higher in Jinwu compared to DLY, indicating that these bacterial genera confer Jinwu with a higher tolerance to roughage than DLY.

Alteration of the gut microbial composition of critically endangered Malayan tigers (Panthera tigris jacksoni) in captivity during enrichment phase

BACKGROUND

Enrichment activities may influence the microbiomes of captive tigers', affecting their health, digestion, and behavior. Currently, there are few studies that address the impact of enrichment activity on tigers' health. This study aimed to determine the diversity of the gut microbiome in captive Malayan tigers at Zoo Melaka and Night Safari during the environmental enrichment phase using a metabarcoding approach.

METHODS AND RESULTS

This study utilized different enrichment activities which catered for food, sensory, and cognitive enrichment. Eleven fresh fecal samples from captive Malayan tigers at Zoo Melaka and Night Safari were collected under different conditions. All samples were extracted and 16S rRNA V3-V4 region amplicon sequencing was used to characterize the gut microbiome of captive Malayan tigers subjected to various enrichment activities. Firmicutes, Actinobacteriota, and Fusobacteriota were the dominant phyla observed in the gut microbiome of captive Malayan tigers during enrichment activities. This study revealed β-diversity significantly varied between normal and enrichment phase, however no significant differences were observed in α-diversity. This study demonstrates that environmental enrichment improves the gut microbiome of Malayan tigers because gut microbes such as Lachnoclostridium, which has anti-inflammatory effects and helps maintain homeostasis, and Romboutsia, which has a probiotic effect on the gut microbiome.

CONCLUSIONS

This study provides valuable insights into the effects of enrichment activities on the gut microbiome of captive Malayan tigers, offering guidance for enhancing captive management practices aimed at promoting the health and well-being of Malayan tiger in captivity.

The effect of dietary zinc and zinc physiological status on the composition of the gut microbiome in vivo

Zinc serves critical catalytic, regulatory, and structural roles. Hosts and their resident gut microbiota both require zinc, leading to competition, where a balance must be maintained. This systematic review examined evidence on dietary zinc and physiological status (zinc deficiency or high zinc/zinc overload) effects on gut microbiota. This review was conducted according to PRISMA (Preferred Reporting Items for Systematic reviews and Meta-Analyses) guidelines and registered in PROSPERO (CRD42021250566). PubMed, Web of Science, and Scopus databases were searched for in vivo (animal) studies, resulting in eight selected studies. Study quality limitations were evaluated using the SYRCLE risk of bias tool and according to ARRIVE guidelines. The results demonstrated that zinc deficiency led to inconsistent changes in α-diversity and short-chain fatty acid production but led to alterations in bacterial taxa with functions in carbohydrate metabolism, glycan metabolism, and intestinal mucin degradation. High dietary zinc/zinc overload generally resulted in either unchanged or decreased α-diversity, decreased short-chain fatty acid production, and increased bacterial metal resistance and antibiotic resistance genes. Additional studies in human and animal models are needed to further understand zinc physiological status effects on the intestinal microbiome and clarify the applicability of utilizing the gut microbiome as a potential zinc status biomarker.

Genetic insights into the gut microbiota, herpes zoster, and postherpetic neuralgia: a bidirectional two-sample Mendelian randomization study

Background

An increasing amount of evidence suggests that gastrointestinal diseases are risk factors for herpes zoster (HZ) and postherpetic neuralgia (PHN). Among them, the gut microbiota may play a crucial role in this process. Therefore, this study aims to explore the potential causal association between the gut microbiota and HZ and PHN.

Methods

Bidirectional two-sample Mendelian randomization (MR) analysis was used to detect the causal effect between HZ and PHN and the gut microbiota. Gut microbiota data were derived from the MiBioGen consortium, while HZ and PHN data were obtained from the FinnGen database. We selected single-nucleotide polymorphisms (SNPs) as instrumental variables with a threshold of p < 1 × 10⁻⁵ for the association with the gut microbiota in forward MR analysis and p < 5 × 10⁻8 for the association with HZ or PHN in reverse MR analysis and then removed SNPs in linkage disequilibrium (r 2 < 0.001) within a distance of 10,000 kb for both the gut microbiota and HZ and PHN. These SNPs were utilized to assess the causal effect between exposures and outcomes using inverse-variance weighting (IVW), MR-Egger, weighted mean, and weighted median tests.

Results

The class Deltaproteobacteria, order Desulfovibrionales, family Desulfovibrionaceae, and genus Coprococcus 2 were found to reduce the risk of HZ, while the phylum Cyanobacteria, genus Eubacterium rectale group appeared to increase it. The class Coriobacteriia, order Coriobacteriales, family Coriobacteriaceae, genus Lachnospiraceae NK4A136 and genus Ruminococcaceae UCG011 were found to reduce the risk of PHN, while the genus Candidatus Soleaferrea, genus Eubacterium rectale group, and genus Methanobrevibacter appeared to increase it. Moreover, the onset of HZ was found to increase the level of the genus Eubacterium rectale group. These findings remained robust and unaffected by heterogeneity or horizontal pleiotropy among SNPs in both forward and reverse MR analysis.

Conclusion

This MR study provided evidence supporting a potential causal relationship between the gut microbiota and HZ and PHN. Moreover, we found that the causal effect between the gut microbiota and HZ is bidirectional. Further studies are required to clarify the biological mechanisms linking the gut microbiota and these conditions.

Gut Microbiome Multi-Omics and Cognitive Function in the Hispanic Community Health Study/Study of Latinos- Investigation of Neurocognitive Aging

INTRODUCTION

We conducted a study within the Hispanic Community Health Study/Study of Latinos- Investigation of Neurocognitive Aging (HCHS/SOL-INCA) cohort to examine the association between gut microbiome and cognitive function.

METHODS

We analyzed the fecal metagenomes of 2,471 HCHS/SOL-INCA participants to, cross-sectionally, identify microbial taxonomic and functional features associated with global cognitive function. Omnibus (PERMANOVA) and feature-wise analyses (MaAsLin2) were conducted to identify microbiome-cognition associations, and specific microbial species and pathways (Kyoto Encyclopedia of Genes and Genomes (KEGG modules) associated with cognition.

RESULTS

Eubacterium species( E. siraeum and E. eligens ), were associated with better cognition. Several KEGG modules, most strongly Ornithine, Serine biosynthesis and Urea Cycle, were associated with worse cognition.

DISCUSSION

In a large Hispanic/Latino cohort, we identified several microbial taxa and KEGG pathways associated with cognition.

Bridging the Gap: Harnessing Plant Bioactive Molecules to Target Gut Microbiome Dysfunctions in Amyotrophic Lateral Sclerosis

The correlation between neurodegenerative diseases and the gut microbiome is increasingly evident, with amyotrophic lateral sclerosis (ALS) being particularly notable for its severity and lack of therapeutic options. The gut microbiota, implicated in the pathogenesis and development of ALS, plays a crucial role in the disease. Bioactive plant molecules, specifically volatile compounds in essential oils, offer a promising therapeutic avenue due to their anti-inflammatory properties and gut-modulating effects. Our narrative review aimed to identify microbiota-associated bacteria in ALS and analyze the benefits of administering bioactive plant molecules as much-needed therapeutic options in the management of this disease. A comprehensive search of PubMed database articles published before December 2023, encompassing research on cell, human, and animal ALS models, was conducted. After selecting, analyzing, and discussing key articles, bacteria linked to ALS pathogenesis and physiopathology were identified. Notably, positively highlighted bacteria included Akkermansia muciniphila (Verrucomicrobia phylum), Faecalibacterium prausnitzii, and Butyrivibrio spp. (Firmicutes phylum). Conversely, members of the Escherichia coli spp. (Proteobacteria phylum) and Ruminococcus spp. (Firmicutes phylum) stood out negatively in respect to ALS development. These bacteria were associated with molecular changes linked to ALS pathogenesis and evolution. Bioactive plant molecules can be directly associated with improvements in the microbiome, due to their role in reducing inflammation and oxidative stress, emerging as one of the most promising natural agents for enriching present-day ALS treatments.

Causal relationship between gut microbiota and gastric cancer: A two‑sample Mendelian randomization analysis

The gut microbiota is associated with GC; however, the causal association between the gut microbiota and GC remains to be determined. The aim of the present study was to investigate the causal association between gut microbiota and gastric cancer (GC) from the perspective of Mendelian randomization (MR). The present study performed MR analysis using summary statistics from a genome-wide association study of the gut microbiome and GC. Inverse-variance weighted, MR-Egger and weighted median methods were used to investigate the causal relationship between gut microbiota and GC. Heterogeneity tests were performed using Cochrane's Q statistic. Horizontal polytropy was detected using Mendelian Randomization Pleiotropy RESidual Sum and Outlier were eliminated. Estimates from MR indicated that nine gut microorganism remained stable with regard to acceptance of heterogeneity and sensitivity methods. Among them, the genera Prevotella 7, Roseburia and Ruminococcaceae UCG014 were associated with an increased risk of GC; by contrast, the family Enterobacteriaceae, the genera Allisonella, Lachnospiraceae FCS020, Ruminococcaceae UCG004 and Ruminococcaceae UCG009, and the order Enterobacteriales decreased the risk of GC development. The present study demonstrated the potential importance of modulating the abundance of gut microbiota for the prevention and treatment of GC.

Metabolic and inflammatory perturbation of diabetes associated gut dysbiosis in people living with and without HIV infection

BACKGROUND

Gut dysbiosis has been linked with both HIV infection and diabetes, but its interplay with metabolic and inflammatory responses in diabetes, particularly in the context of HIV infection, remains unclear.

METHODS

We first conducted a cross-sectional association analysis to characterize the gut microbial, circulating metabolite, and immune/inflammatory protein features associated with diabetes in up to 493 women (~ 146 with prevalent diabetes with 69.9% HIV +) of the Women's Interagency HIV Study. Prospective analyses were then conducted to determine associations of identified metabolites with incident diabetes over 12 years of follow-up in 694 participants (391 women from WIHS and 303 men from the Multicenter AIDS Cohort Study; 166 incident cases were recorded) with and without HIV infection. Mediation analyses were conducted to explore whether gut bacteria-diabetes associations are explained by altered metabolites and proteins.

RESULTS

Seven gut bacterial genera were identified to be associated with diabetes (FDR-q <  0.1), with positive associations for Shigella, Escherichia, Megasphaera, and Lactobacillus, and inverse associations for Adlercreutzia, Ruminococcus, and Intestinibacter. Importantly, the associations of most species, especially Adlercreutzia and Ruminococcus, were largely independent of antidiabetic medications use. Meanwhile, 18 proteins and 76 metabolites, including 3 microbially derived metabolites (trimethylamine N-oxide, phenylacetylglutamine (PAGln), imidazolepropionic acid (IMP)), 50 lipids (e.g., diradylglycerols (DGs) and triradylglycerols (TGs)) and 23 non-lipid metabolites, were associated with diabetes (FDR-q <  0.1), with the majority showing positive associations and more than half of them (59/76) associated with incident diabetes. In mediation analyses, several proteins, especially interleukin-18 receptor 1 and osteoprotegerin, IMP and PAGln partially mediate the observed bacterial genera-diabetes associations, particularly for those of Adlercreutzia and Escherichia. Many diabetes-associated metabolites and proteins were altered in HIV, but no effect modification on their associations with diabetes was observed by HIV.

CONCLUSION

Among individuals with and without HIV, multiple gut bacterial genera, blood metabolites, and proinflammatory proteins were associated with diabetes. The observed mediated effects by metabolites and proteins in genera-diabetes associations highlighted the potential involvement of inflammatory and metabolic perturbations in the link between gut dysbiosis and diabetes in the context of HIV infection.

Gut Microbial Dysbiosis Differs in Two Distinct Cachectic Tumor-Bearing Models Consuming the Same Diet

The impact of cancer cachexia on the colonic microbiota is poorly characterized. This study assessed the effect of two cachectic-producing tumor types on the gut microbiota to determine if a similar dysbiosis could be found. In addition, it was determined if a diet containing an immunonutrient-rich food (walnuts) known to promote the growth of probiotic bacteria in the colon could alter the dysbiosis and slow cachexia. Male Fisher 344 rats were randomly assigned to a semi-purified diet with or without walnuts. Then, within each diet group, rats were further assigned randomly to a treatment group: tumor-bearing ad libitum fed (TB), non-tumor-bearing ad libitum fed (NTB-AL), and non-tumor-bearing group pair-fed to the TB (NTB-PF). The TB group was implanted either with the Ward colon carcinoma or MCA-induced sarcoma, both transplantable tumor lines. Fecal samples were collected after the development of cachexia, and bacteria species were identified using 16S rRNA gene analysis. Both TB groups developed cachexia but had a differently altered gut microbiome. Beta diversity was unaffected by treatment (NTB-AL, TB, and NTB-PF) regardless of tumor type but was affected by diet. Also, diet consistently changed the relative abundance of several bacteria taxa, while treatment and tumor type did not. The control diet increased the abundance of A. Anaeroplasma, while the walnut diet increased the genus Ruminococcus. There were no common fecal bacterial changes characteristic of cachexia found. Diet consistently changed the gut microbiota, but these changes were insufficient to slow the progression of cachexia, suggesting cancer cachexia is more complex than a few gut microbiota shifts.