Linking Gut Microbiota Research Articles

The Role of Gut Microbiota Dysbiosis in Erectile Dysfunction: From Pathophysiology to Treatment Strategies

Erectile dysfunction (ED) is a prevalent male sexual disorder characterized by the persistent inability to achieve or maintain an erection sufficient for satisfactory sexual performance. While its etiology is multifactorial, encompassing vascular, neurological, hormonal, and psychological components, emerging evidence suggests a significant role for gut microbiota dysbiosis in its development. The gut microbiota influences various metabolic, inflammatory, and neuropsychological processes critical to erectile function. Dysbiosis can lead to systemic inflammation, endothelial dysfunction, hormonal imbalances, and altered neurotransmitter production, all of which are key factors in ED pathogenesis. This narrative review synthesizes current research on the association between gut microbiota alterations and ED, highlighting specific bacterial taxa implicated in ED through mechanisms involving inflammation, metabolic disturbances, and hormonal regulation. This review explores potential mechanisms linking gut microbiota and ED, including pro-inflammatory cytokines, gut barrier integrity disruption, metabolic disorders, psychological factors via the gut–brain axis, and hormonal regulation. Furthermore, the gut microbiota offers promising avenues for developing non-invasive biomarkers and therapeutic interventions such as probiotics, prebiotics, dietary modifications, and fecal microbiota transplantation. Future research should focus on longitudinal studies, mechanistic explorations, and clinical trials to validate these findings and translate them into clinical practice. Understanding the interplay between the gut microbiota and erectile function could unveil novel diagnostic biomarkers and pave the way for innovative treatments targeting the microbiota, ultimately improving men’s sexual and overall health.

Integrative multi-omics analysis of autism spectrum disorder reveals unique microbial macromolecules interactions.

Gut microbiota alterations have been implicated in Autism Spectrum Disorder (ASD), yet the mechanisms linking these changes to ASD pathophysiology remain unclear. This study utilized a multi-omics approach to uncover mechanisms linking gut microbiota to ASD by examining microbial diversity, bacterial metaproteins, associated metabolic pathways and host proteome. The gut microbiota of 30 children with severe ASD and 30 healthy controls was analyzed. Microbial diversity was assessed using 16S rRNA V3 and V4 sequencing. A novel metaproteomics pipeline identified bacterial proteins, while untargeted metabolomics explored altered metabolic pathways. Finally, multi-omics integration was employed to connect macromolecular changes to neurodevelopmental deficits. Children with ASD exhibited significant alterations in gut microbiota, including lower diversity and richness compared to controls. Tyzzerella was uniquely associated with the ASD group. Microbial network analysis revealed rewiring and reduced stability in ASD. Major metaproteins identified were produced by Bifidobacterium and Klebsiella (e.g., xylose isomerase and NADH peroxidase). Metabolomics profiling identified neurotransmitters (e.g., glutamate, DOPAC), lipids, and amino acids capable of crossing the blood-brain barrier, potentially contributing to neurodevelopmental and immune dysregulation. Host proteome analysis revealed altered proteins, including kallikrein (KLK1) and transthyretin (TTR), involved in neuroinflammation and immune regulation. Finally, multi-omics integration supported single-omics findings and reinforced the hypothesis that gut microbiota and their macromolecular products may contribute to ASD-associated symptoms. The integration of multi-omics data provided critical evidence that alteration in gut microbiota and associated macromolecule production may play a role in ASD-related symptoms and co-morbidities. Key bacterial metaproteins and metabolites were identified as potential contributors to neurological and immune dysregulation in ASD, underscoring possible novel targets for therapeutic intervention.

The role of the microbiota-gut-brain axis and artificial intelligence in cognitive health of pediatric obstructive sleep apnea: A narrative review.

Pediatric obstructive sleep apnea (OSA) is a prevalent sleep-related breathing disorder associated with significant neurocognitive and behavioral impairments. Recent studies have highlighted the role of gut microbiota and the microbiota-gut-brain axis (MGBA) in influencing cognitive health in children with OSA. This narrative review aims to summarize current knowledge on the relationship between gut microbiota, MGBA, and cognitive function in pediatric OSA. It also explores the potential of artificial intelligence and machine learning in advancing this field and identifying novel therapeutic strategies. Pediatric OSA is associated with gut dysbiosis, reduced microbial diversity, and metabolic disruptions. MGBA mechanisms, such as endocrine, immune, and neural pathways, link gut microbiota to cognitive outcomes. Artificial intelligence and machine learning methodologies offer promising tools to uncover microbial markers and mechanisms associated with cognitive deficits in OSA. Future research should focus on validating these findings through clinical trials and developing personalized therapeutic approaches targeting the gut microbiota.

Gut microbiome and bone health: update on mechanisms, clinical correlations, and possible treatment strategies.

The intestinal microbiome is increasingly regarded as a relevant modulator of the pathophysiology of several age-related conditions, including frailty, sarcopenia, and cognitive decline. Aging is in fact associated with alteration of the equilibrium between symbiotic bacteria and opportunistic pathogens, leading to dysbiosis. The microbiome is able to regulate intestinal permeability and systemic inflammation, has a central role in intestinal amino acid metabolism, and produces a large number of metabolites and byproducts, with either beneficial or detrimental consequences for the host physiology. Recent evidence, from both preclinical animal models and clinical studies, suggests that these microbiome-centered pathways could contribute to bone homeostasis, regulating the balance between osteoblast and osteoclast function. In this systematic review, we provide an overview of the mechanisms involved in the gut-bone axis, with a particular focus on microbiome function and microbiome-derived mediators including short-chain fatty acids. We also review the current evidence linking gut microbiota dysbiosis with osteopenia and osteoporosis, and the results of the intervention studies on pre-, pro-, or post-biotics targeting bone mineral density loss in both animal models and human beings, indicating knowledge gaps and highlighting possible avenues for future research.

Exploring the Characteristics of Gut Microbiota Associated with Depression via the Depression Assessment Scales.

Depression is a prevalent mental disorder with an increasing economic burden, and its pathogenesis remains poorly understood. Given the emerging evidence linking gut microbiota to mental health, a better understanding of microbial profiles associated with depression is necessary. Here, we explore the association between gut microbiota and depression by utilizing 16S rRNA amplicon sequencing and depression assessment scales, including the Hamilton Depression Rating Scale (HDRS) and the Beck Depression Inventory (BDI). The study cohort consisted of 46 subjects, categorized into depression and normal groups based on medical diagnoses and depression scale scores. Our analyses revealed that HDRS-based classification better identified distinct gut microbiota structures associated with depression than medical diagnoses alone. Notably, lower beta diversity was observed in individuals with depression, indicating a more homogeneous gut microbial community. By employing both HDRS and BDI scores simultaneously, we identified specific taxa, such as Bilophila and Alistipes, which are linked to depressive symptoms. These findings highlight the potential of using depression assessment scales in conjunction with gut microbiota data to advance our understanding of depression and inform future treatment strategies.

Microbiota and social behavior alterations in a mouse model of down syndrome: Modulation by a synbiotic treatment

Sex differences in the composition and functionality of gut microbiota are an emerging field of interest in neurodevelopmental disorders, as they may help in understanding the phenotypic disparities between males and females. This study aimed to characterize sex-related specific alterations in gut microbiota composition in a mouse model of Down syndrome (Ts65Dn mice, TS mice) through the sequencing of the PCR-amplified 16S ribosomal DNA fraction. Moreover, it intended to examine whether the modulation of gut microbiota by the administration of a synbiotic (SYN) treatment would be beneficial for the behavioral alterations observed in male and female TS mice. Our results show that male, but not female, TS mice exhibit alterations in beta diversity compared to their wild-type (WT) littermates. Sex-dependent differences are also observed in the relative abundance of the classes Bacilli and Clostridia. Administering the SYN effectively counteracts hypersociability in females, and normalizes the overall abundance of Bacilli, specifically by increasing Lactobacillaceae. On the contrary, it rescues emotional recognition deficits in male TS mice and increases the relative abundance of the families Lactobacillaceae, Streptococcaceae and Atopobiaceae. In addition, a metagenome KEGG analysis of differentially enriched pathways shows relevant changes in the cofactor biosynthesis and the amino acid synthesis categories. Finally, following SYN treatment, both male and female TS mice exhibit a robust increase in propionic acid levels compared to WT littermates. These findings suggest sex-specific mechanisms that could link gut microbiota composition with behavior in TS mice, and underscore the potential of targeted gut microbiota interventions to modulate social abnormalities in neurodevelopmental disorders.

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

The correlation between the gut microbiota and airway inflammation in childhood allergic rhinitis (AR), particularly concerning allergen exposure, remains insufficiently explored. This study aimed to link gut microbiota changes with house dust mite (HDM)-specific IgE responses in pediatric AR. Using metagenomic shotgun sequencing, we compared the fecal microbiota of 60 children with HDM-AR to 48 healthy controls (HC), analyzing the link to IgE reactions. We examined the effects of oral Escherichia (E.) fergusonii treatment in mice sensitized with ovalbumin and HDM on allergic symptoms, mucosal cell infiltration, Th1/Th2/Tregs balance in the spleen, serum cytokine levels, and E. fergusonii presence in feces. Children with HDM-AR have a less diverse gut microbiome and lower levels of E. fergusonii compared to controls, with a negative correlation between E. fergusonii abundance and HDM-specific IgE levels. In mice sensitized with OVA and HDM, oral administration of E. fergusonii improved allergic symptoms, reduced nasal eosinophils/mast cells infiltration and adjusted Th cell populations towards a non-allergic profile in splenic lymphocytes with exception of IFN-γ change in serum. These findings underline the potential of targeting gut microbiota, particularly E. fergusonii, in managing childhood HDM-AR, suggesting a promising approach for future interventions. The composition and distribution of gut microbiota in children with HDM-AR are significant changed. The abundance of Escherichia genus is decreased in HDM-AR children. HDM-specific IgE levels are strongly negatively associated with E. fergusonii abundance. Oral administration of E. fergusonii effectively suppresses allergic responses in murine model. These findings offer novel insights into the diagnosis and treatment of HDM-AR, which suggested that E. fergusonii holds promise as a potential therapeutic avenue for managing HDM-AR.

Exploring the causal pathway from gut microbiota to polycystic ovary syndrome: A network Mendelian randomization study.

Polycystic ovary syndrome (PCOS) is a complicated endocrine and metabolic syndrome with unclear pathogenesis. The gut microbiota sheds light on the etiology and pathophysiology of PCOS. We used Mendelian randomization (MR) studies to systematically evaluate the pathological mechanism gut microbiota causally associated with PCOS risk. A network MR analysis was performed to estimate the causal effects of gut microbiota and risk factors on PCOS, as well as the mediation effect of risk factors linking gut microbiota to PCOS. The investigation of side effects for the important gut microbiota was subsequently broadened to include phenotypes by performing Phenowide-MR analysis for a range of diseases. Genus Sellimonas id.14369 were causally associated with reduced PCOS risk (odds ratio [OR] = 0.69, 95% confidence interval [CI]: 0.58-0.84, P = 1.22 × 10-4) after multiple testing correction. And Sellimonas retained consistent causal effect estimates after a series of sensitivity analyses. In addition, we observed an indirect effect of Sellimonas on PCOS through body mass index (BMI) using network MR (b = -0.05, 95% CI: -0.09 to -0.01), with a mediated proportion of 12.82% of the total effect. Further, Phenowide-MR analyses showed that the protective effects of Sellimonas on type 2 diabetes and depression (for type 2 diabetes: OR = 0.95, 95% CI: 0.90-0.99, P = .0366; for depression: OR = 0.99, 95% CI: 0.98-1.00, P = .0210). We summarized that the causal path between gut microbiota and type 2 diabetes are also jointly mediated by BMI. Sellimonas may be a protective factor of PCOS, which can affect the occurrence of PCOS through BMI, supporting future studies on the importance of addressing obesity and metabolic issues in preventing and managing PCOS.

Linking gut microbiota dysbiosis to molecular pathways in Alzheimer’s disease

BackgroundAlzheimer’s disease (AD) is a progressive neurodegenerative disorder marked by cognitive decline and synaptic dysfunction. Emerging evidence suggests a significant relationship between gut microbiota and brain health, mediated through the gut-brain axis. Alterations in gut microbiota composition may influence AD progression by affecting molecular pathways and miRNA interactions. MethodsWe retrieved and analyzed microarray data from 34 tissue samples of AD patients and controls (GEO accession number GSE110298). Differentially expressed genes (DEGs) with the GCS score package in R, considering a p-value < 0.05 and logFC<-1 and logFC>1 to isolate significant gene clusters. Enrichment analysis of signaling pathways and gene ontology was conducted using Enrichr, KEGG, Panther, DAVID, and shiny GO databases. Protein-protein interactions were visualized with Networkanalyst and CytoScape. Gut microbiota in 200 CE patients was analyzed using next-generation sequencing (NGS) data from gutMDisorder and GMrepo databases. miRNA interactions were evaluated using miEAA, Targetscan, MienTurnet, and miRnet databases. ResultsSignificant reductions in microbial taxa, including Clostridia (LDA score −4.878208), Firmicutes (LDA score −4.817032), and Faecalibacterium (LDA score −4.40714), were observed in AD patients. Pathway analysis highlighted the involvement of Axon guidance, ErbB, and MAPK signaling pathways in AD. Venn diagram analysis identified 619 intersecting genes in brain and gut tissues, emphasizing pathways such as Axon Guidance and Cell Cycle. miRNA analysis revealed important regulatory miRNAs, including hsa-let-7c, hsa-mir-125b-2, and hsa-mir-145, which target key transcription factors involved in AD pathology. ConclusionThe study demonstrates significant dysbiosis in the gut microbiota of AD patients and underscores the potential role of gut microbiota in AD progression through altered signaling pathways and miRNA interactions. These findings highlight the need for further research into microbiota-based interventions as potential therapeutic strategies for AD.

Integrative metagenomic and lipidomic analyses reveal alterations in children with obesity and after lifestyle intervention.

Despite emerging evidence linking alterations in gut microbiota to childhood obesity, the metabolic mechanisms linking gut microbiota to the lipid profile during childhood obesity and weight loss remain poorly understood. In this study, children with obesity were treated with lifestyle weight loss therapy. Metagenomics association studies and serum untargeted lipidomics analyses were performed in children with obesity and healthy controls before and after weight loss. We identified alterations in gut microbiota associated with childhood obesity, as well as variations in circulating metabolite concentrations. Children with obesity showed significant decreases in the levels of s-Rothia_kristinae and s-Enterobacter_roggenkampii, alongsige elevated levels of s-Clostridiales_bacterium_Marseille-P5551. Following weight loss, the levels of s-Streptococcus_infantarius and s-Leuconostoc_citreum increased by factors of 3.354 and 1.505, respectively, in comparison to their pre-weight loss levels. Correlation analyses indicated a significant positive relationship between ChE(2:0) levels and both with s-Lachnospiraceae_bacterium_TF09-5 and fasting glucose levels. CoQ8 levels were significantly negatively correlated with s-Rothia_kristinae and HOMA-IR. We linked altered gut microbiota and serum lipid levels in children with obesity to clinical indicators, indicating a potential impact on glucose metabolism via lipids. This study contributes to understanding the mechanistic relationship between altered gut microbiota and childhood obesity and weight loss, suggesting gut microbiome as a promising target for intervention. https://www.chictr.org.cn/showproj.html?proj=178971, ChiCTR2300072179.

Association of Lipopolysaccharide-Type Endotoxins with Retinal Neurodegeneration: The Alienor Study

PurposeLipopolysaccharide (LPS) -type endotoxins are naturally found in the gut microbiota and there is emerging evidence linking gut microbiota and neuroinflammation leading to retinal neurodegeneration. Thinning of the retinal nerve fiber layer (RNFL) is a biomarker of retinal neurodegeneration, and a hallmark of glaucoma, the second leading cause of blindness worldwide. We assessed the association of a blood biomarker of LPS with peripapillary RNFL thickness (RNFLT) and its longitudinal evolution up to 11 years. DesignThe Alienor study is a single center prospective population-based cohort study. SubjectsThe studied sample of this study includes 1062 eyes of 548 participants receiving at least one gradable RNFL measurement. MethodsPlasma esterified 3-hydroxy fatty acids (3-OH FAs) were measured as a proxy of LPS burden. RNFLT was acquired using spectral domain optical coherence tomography imaging every two years from 2009 to 2020 (up to 5 visits). Main Outcome MeasureAssociations of plasma esterified 3-OH FAs with RNFLT were assessed using linear mixed models. ResultsMean age of the included 548 participants was 82.4 ± 4.3 years and 62.6 % were women. Higher plasma esterified 3-OH FAs was significantly associated with thinner RNFLT at baseline (Coefficient Beta (ß)= -1.42 microns for 1 SD-increase in 3-OH FAs, 95% confidence interval [-2.56; -0.28], p = 0.02). This association remained stable after multivariate adjustment for potential confounders. No statistically significant association was found between 3-OH FAs and longitudinal RNFLT change. ConclusionsHigher plasma esterified 3-OH FAs were associated with thinner RNFLT at baseline, indicating an involvement of LPS in the early processes of optic nerve neurodegeneration and highlighting the potential importance of the human microbiota in preserving retinal health.

Exploring the Role of the Gut Microbiota in Modulating Colorectal Cancer Immunity.

The gut microbiota plays an essential role in maintaining immune homeostasis and influencing the immune landscape within the tumor microenvironment. This review aims to elucidate the interactions between gut microbiota and tumor immune dynamics, with a focus on colorectal cancer (CRC). The review spans foundational concepts of immuno-microbial interplay, factors influencing microbiome composition, and evidence linking gut microbiota to cancer immunotherapy outcomes. Gut microbiota modulates anti-cancer immunity through several mechanisms, including enhancement of immune surveillance and modulation of inflammatory responses. Specific microbial species and their metabolic byproducts can significantly influence the efficacy of cancer immunotherapies. Furthermore, microbial diversity within the gut microbiota correlates with clinical outcomes in CRC, suggesting potential as a valuable biomarker for predicting response to immunotherapy. Conclusions: Understanding the relationship between gut microbiota and tumor immune responses offers potential for novel therapeutic strategies and biomarker development. The gut microbiota not only influences the natural history and treatment response of CRC but also serves as a critical modulator of immune homeostasis and anti-cancer activity. Further exploration into the microbiome's role could enhance the effectiveness of existing treatments and guide the development of new therapeutic modalities.

Age-associated temporal decline in butyrate-producing bacteria plays a key pathogenic role in the onset and progression of neuropathology and memory deficits in 3×Tg-AD mice

ABSTRACT Alterations in the gut-microbiome-brain axis are increasingly being recognized to be involved in Alzheimer’s disease (AD) pathogenesis. However, the functional consequences of enteric dysbiosis linking gut microbiota and brain pathology in AD progression remain largely undetermined. The present work investigated the causal role of age-associated temporal decline in butyrate-producing bacteria and butyrate in the etiopathogenesis of AD. Longitudinal metagenomics, neuropathological, and memory analyses were performed in the 3×Tg-AD mouse model. Metataxonomic analyses showed a significant temporal decline in the alpha diversity marked by a decrease in butyrate-producing bacterial communities and a concurrent reduction in cecal butyrate production. Inferred metagenomics analysis identified the bacterial acetyl-CoA pathway as the main butyrate synthesis pathway impacted. Concomitantly, there was an age-associated decline in the transcriptionally permissive acetylation of histone 3 at lysines 9 and 14 (H3K9/K14-Ac) in hippocampal neurons. Importantly, these microbiome-gut-brain changes preceded AD-related neuropathology, including oxidative stress, tau hyperphosphorylation, memory deficits, and neuromuscular dysfunction, which manifest by 17–18 months. Initiation of oral administration of tributyrin, a butyrate prodrug, at 6 months of age mitigated the age-related decline in butyrate-producing bacteria, protected the H3K9/K14-Ac status, and attenuated the development of neuropathological and cognitive changes associated with AD pathogenesis. These data causally implicate age-associated decline in butyrate-producing bacteria as a key pathogenic feature of the microbiome-gut-brain axis affecting the onset and progression of AD. Importantly, the regulation of butyrate-producing bacteria and consequent butyrate synthesis could be a significant therapeutic strategy in the prevention and treatment of AD.

Microbiome dysbiosis in gallbladder cancer: A systemic review

Gallbladder cancer (GBC) starts in the epithelial tissue (lining of the bile duct and gallbladder). It is a type of aggressive cancer called adenocarcinoma that can spread to other tissues. Among all cases of biliary tract cancer, 50% is from GBC. It is a deadly cancer with a survival rate of 17.6% between 2007 and 2013. GBC is rarely found in the Western world, but it is commonly found in South Asia. In Southeast Asian countries, GBC plays a significant role in cancer-related morbidity and mortality. GBC incidence exhibits marked regional variability, a rare condition in the western population but having a higher frequency in India, especially the Indo-Gangetic belt and some northeast districts excluding Nagaland. This might be attributed to the differences in environmental factors and genetic predisposition modulating carcinogenesis. In GBC, only 10% of cases are identified in the early stages. The low rate of early detection is due to the lack of screening techniques and the aggressive characteristics of the tumor. Various risk factors are associated with GBC, for example, chronic cholecystitis with or without gallstones, obesity, exposure to heavy metals such as lead and arsenic, bacterial infection, congenital biliary cysts, and abnormal pancreaticobiliary duct junction. The risk factors can cause chronic gallbladder mucosa irritation, leading to dysplasia and neoplasia. GBC can form metaplasia to dysplasia in a time span of 5–15 years, then to carcinoma in situ, and finally to invasive cancer. Dysbiosis is responsible for various diseases, including cancer. Multiple triggers can cause dysbiosis, for example, environmental changes, inflammation, infection, medications, dietary changes, or genetic predisposition. Various researches show that Helicobacter pylori, human papillomavirus, Hepatitis B virus, and Hepatitis C virus microbial species can cause cancer. They are the major species responsible for 90% of infection-associated cancers. Various studies demonstrate that the strains of Salmonella and Helicobacter colonize are linked to developing GBC. While the mechanisms linking gut microbiota to GBC are not fully understood, several studies have suggested a potential association. According to a study, certain gut microbiomes, such as Fusobacterium nucleatum, found glut in GBC tissues, compared to adjacent normal tissues. By evaluating gut microbiome dysbiosis, we can see the potential link between gut microbiome dysbiosis and GBC; it may provide valuable insights into the development and progression of GBC. It could lead to the identification of new diagnostic markers and the development of novel therapeutic strategies. In GBC, the evaluation of gut microbiome dysbiosis (involving evaluating the composition, diversity, and functional capacity of the gut microbiome in patients) has emerged as a promising method for understanding the molecular mechanisms and identifying biomarkers for early prevention and detection of GBC and also investigating the possibility of any link between the gut microbiome and host immune response. In conclusion, evaluating gut microbiome dysbiosis in GBC is a promising direction for identifying potential early detection and prevention biomarkers. Additional investigation is therefore needed to determine the role of gut microbiome dysbiosis in the development and progression of GBC and to identify reliable biomarkers for clinical use.

Large-scale genetic correlation studies explore the causal relationship and potential mechanism between gut microbiota and COVID-19-associated risks

Recent observational studies suggest that gut microorganisms are involved in the onset and development of coronavirus disease 2019 (COVID-19), but the potential causal relationship behind them remains unclear. Exposure data were derived from the MiBioGen consortium, encompassing 211 gut microbiota (n = 18,340). The outcome data were sourced from the COVID-19 host genetics initiative (round 7), including COVID-19 severity (n = 1,086,211), hospitalization (n = 2,095,324), and susceptibility (n = 2,597,856). First, a two-sample Mendelian randomization (TSMR) was performed to investigate the causal effect between gut microbiota and COVID-19 outcomes. Second, a two-step MR was used to explore the potential mediators and underlying mechanisms. Third, several sensitivity analyses were performed to verify the robustness of the results. Five gut microbes were found to have a potential causality with COVID-19 severity, namely Betaproteobacteria (beta = 0.096, p = 0.034), Christensenellaceae (beta = -0.092, p = 0.023), Adlercreutzia (beta = 0.072, p = 0.048), Coprococcus 1 (beta = 0.089, p = 0.032), Eisenbergiella (beta = 0.064, p = 0.024). Seven gut microbes were found to have a potential causality with COVID-19 hospitalization, namely Victivallaceae (beta = 0.037, p = 0.028), Actinomyces (beta = 0.047, p = 0.046), Coprococcus 2 (beta = -0.061, p = 0.031), Dorea (beta = 0.067, p = 0.016), Peptococcus (beta = -0.035, p = 0.049), Rikenellaceae RC9 gut group (beta = 0.034, p = 0.018), and Proteobacteria (beta = -0.069, p = 0.035). Two gut microbes were found to have a potential causality with COVID-19 susceptibility, namely Holdemanella (beta = -0.024, p = 0.023) and Lachnospiraceae FCS020 group (beta = 0.026, p = 0.027). Multi-omics mediation analyses indicate that numerous plasma proteins, metabolites, and immune factors are critical mediators linking gut microbiota with COVID-19 outcomes. Sensitivity analysis suggested no significant heterogeneity or pleiotropy. These findings revealed the causal correlation and potential mechanism between gut microbiota and COVID-19 outcomes, which may improve our understanding of the gut-lung axis in the etiology and pathology of COVID-19 in the future.

Causal Relationship Between Gut Microbiota, Metabolites, and Sarcopenia: A Mendelian Randomization Study.

Gut microbiota imbalance and sarcopenia are frequently observed in older adults. Gut microbiota and their metabolites are considered risk factors contributing to the heightened risk of sarcopenia, but whether these associations are causal remains unclear. We conducted linkage disequilibrium score regression and 2-sample Mendelian randomization (MR) methods with single-nucleotide polymorphisms sourced from large-scale genome-wide association studies as instrumental variables to examine the causal associations linking gut microbiota with their metabolites to the sarcopenia. Following the MR analysis, subsequent sensitivity analyses were conducted to reinforce the robustness and credibility of the obtained results. MR analysis yielded compelling evidence demonstrating the correlation between genetically predicted gut microbiota and metabolites and the risk of sarcopenia. The abundance of Porphyromonadaceae, Rikenellaceae, Terrisporobacter, and Victivallis was found to be associated with walking pace. Our study also found suggestive associations of 12 intestinal bacteria with appendicular lean mass, and of Streptococcaceae, Intestinibacter, Paraprevotella, Ruminococcaceae UCG009, and Sutterella with grip strength. Specifically, we identified 21 gut microbiota-derived metabolites that may be associated with the risk of sarcopenia. Utilizing a 2-sample MR approach, our study elucidates the causal interplay among gut microbiota, gut microbiota-derived metabolites, and the occurrence of sarcopenia. These findings suggest that gut microbiota and metabolites may represent a potential underlying risk factor for sarcopenia, and offer the promise of novel therapeutic focal points.

Exploring gut microbiota's role in rheumatic valve disease: insights from a Mendelian randomization study and mediation analysis.

Investigating the relationship between gut microbiota and Rheumatic Valve Disease (RVD) is crucial for understanding the disease's etiology and developing effective interventions. Our study adopts a novel approach to examine the potential causal connections between these factors. Utilizing a two-sample Mendelian Randomization (MR) framework, we incorporated a multi-variable MR (MVMR) strategy to assess the mediatory mechanisms involved. This approach involved analyzing data from the MiBioGen consortium for gut microbiota and the FinnGen for RVD, among other sources. Instrumental variables (IVs) were carefully selected based on rigorous MR principles, and statistical analysis was conducted using bidirectional two-sample MR, such as inverse variance-weighted (IVW), weighted median, MR-Egger regression and MR Steiger Test methods. The MR-PRESSO strategy was employed for outlier detection, and MVMR was used to untangle the complex relationships between multiple microbiota and RVD. Our analysis highlighted several gut microbiota classes and families with potential protective effects against RVD, including Lentisphaerae, Alphaproteobacteria, and Streptococcaceae. In contrast, certain genera, such as Eubacterium eligens and Odoribacter, were identified as potential risk factors. The MVMR analysis revealed significant mediation effects of various immune cell traits and biomarkers, such as CD4-CD8- T cells, CD3 on Terminally Differentiated CD8+ T cell and Pentraxin-related protein PTX, elucidating the complex pathways linking gut microbiota to RVD. This study underscores the intricate and potentially causal relationship between gut microbiota and RVD, mediated through a range of immune and hormonal factors. The use of MVMR in our methodological approach provides a more comprehensive understanding of these interactions, highlighting the gut microbiota's potential as therapeutic targets in RVD management. Our findings pave the way for further research to explore these complex relationships and develop targeted interventions for RVD.

A 12-Week, Single-Centre, Randomised, Double-Blind, Placebo-Controlled, Parallel-Design Clinical Trial for the Evaluation of the Efficacy and Safety of Lactiplantibacillus plantarum SKO-001 in Reducing Body Fat.

There is growing evidence linking gut microbiota to overall health, including obesity risk and associated diseases. Lactiplantibacillus plantarum SKO-001, a probiotic strain isolated from Angelica gigas, has been reported to reduce obesity by controlling the gut microbiome. In this double-blind, randomised clinical trial, we aimed to evaluate the efficacy and safety of SKO-001 in reducing body fat. We included 100 participants randomised into SKO-001 or placebo groups (1:1) for 12 weeks. Dual-energy X-ray absorptiometry was used to objectively evaluate body fat reduction. Body fat percentage (p = 0.016), body fat mass (p = 0.02), low-density lipoprotein-cholesterol levels (p = 0.025), and adiponectin levels (p = 0.023) were lower in the SKO-001 group than in the placebo group after 12 weeks of SKO-001 consumption. In the SKO-001 group, the subcutaneous fat area (p = 0.003), total cholesterol levels (p = 0.003), and leptin levels (p = 0.014) significantly decreased after 12 weeks of SKO-001 consumption compared with baseline values. Additionally, SKO-001 did not cause any severe adverse reactions. In conclusion, SKO-001 is safe and effective for reducing body fat and has the potential for further clinical testing in humans.

Alterations in the gut microbiota and its metabolites contribute to metabolic maladaptation in dairy cows during the development of hyperketonemia.

Metabolic maladaptation in dairy cows after calving can lead to long-term elevation of ketones, such as β-hydroxybutyrate (BHB), representing the condition known as hyperketonemia, which greatly influences the health and production performance of cows during the lactation period. Although the gut microbiota is known to alter in dairy cows with hyperketonemia, the association of microbial metabolites with development of hyperketonemia remains unknown. In this study, we performed a multi-omics analysis to investigate the associations between fecal microbial community, fecal/plasma metabolites, and serum markers in hyperketonemic dairy cows during the transition period. Dynamic changes in the abundance of the phyla Verrucomicrobiota and Proteobacteria were detected in the gut microbiota of dairy cows, representing an adaptation to enhanced lipolysis and abnormal glucose metabolism after calving. Random forest and univariate analyses indicated that Frisingicoccus is a key bacterial genus in the gut of cows during the development of hyperketonemia, and its abundance was positively correlated with circulating branched-chain amino acid levels and the ketogenesis pathway. Taurodeoxycholic acid, belonging to the microbial metabolite, was strongly correlated with an increase in blood BHB level, and the levels of other secondary bile acid in the feces and plasma were altered in dairy cows prior to the diagnosis of hyperketonemia, which link the gut microbiota and hyperketonemia. Our results suggest that alterations in the gut microbiota and its metabolites contribute to excessive lipolysis and insulin insensitivity during the development of hyperketonemia, providing fundamental knowledge about manipulation of gut microbiome to improve metabolic adaptability in transition dairy cows.IMPORTANCEAccumulating evidence is pointing to an important association between gut microbiota-derived metabolites and metabolic disorders in humans and animals; however, this association in dairy cows from late gestation to early lactation is poorly understood. To address this gap, we integrated longitudinal gut microbial (feces) and metabolic (feces and plasma) profiles to characterize the phenotypic differences between healthy and hyperketonemic dairy cows from late gestation to early lactation. Our results demonstrate that cows underwent excessive lipid mobilization and insulin insensitivity before hyperketonemia was evident. The bile acids are functional readouts that link gut microbiota and host phenotypes in the development of hyperketonemia. Thus, this work provides new insight into the mechanisms involved in metabolic adaptation during the transition period to adjust to the high energy and metabolic demands after calving and during lactation, which can offer new strategies for livestock management involving intervention of the gut microbiome to facilitate metabolic adaptation.

Causal relationship between gut microbiota and diabetic nephropathy: a two-sample Mendelian randomization study.

Emerging evidence has provided compelling evidence linking gut microbiota (GM) and diabetic nephropathy (DN) via the "gut-kidney" axis. But the causal relationship between them hasn't been clarified yet. We perform a Two-Sample Mendelian randomization (MR) analysis to reveal the causal connection with GM and the development of DN, type 1 diabetes nephropathy (T1DN), type 2 diabetes nephropathy (T2DN), type 1 diabetes mellitus (T1DM), and type 2 diabetes mellitus (T2DM). We used summary data from MiBioGen on 211 GM taxa in 18340 participants. Generalized MR analysis methods were conducted to estimate their causality on risk of DN, T1DN, T2DN, T1DM and T2DM from FinnGen. To ensure the reliability of the findings, a comprehensive set of sensitivity analyses were conducted to confirm the resilience and consistency of the results. It was showed that Class Verrucomicrobiae [odds ratio (OR) =1.5651, 95%CI:1.1810-2.0742,PFDR=0.0018], Order Verrucomicrobiales (OR=1.5651, 95%CI: 1.1810-2.0742, PFDR=0.0018) and Family Verrucomicrobiaceae (OR=1.3956, 95%CI:1.0336-1.8844, PFDR=0.0296) had significant risk of DN. Our analysis found significant associations between GM and T2DN, including Class Verrucomimicrobiae (OR=1.8227, 95% CI: 1.2414-2.6763, PFDR=0.0139), Order Verrucomimicrobiae (OR=1.5651, 95% CI: 1.8227-2.6764, PFDR=0.0024), Rhodospirillales (OR=1.8226, 95% CI: 1.2412-2.6763, PFDR=0.0026), and Family Verrucomicroniaceae (OR=1.8226, 95% CI: 1.2412-2.6763, PFDR=0.0083). The Eubacteriumprotogenes (OR=0.4076, 95% CI: 0.2415-0.6882, PFDR=0.0021) exhibited a protection against T1DN. Sensitivity analyses confirmed that there was no significant heterogeneity and pleiotropy. At the gene prediction level, we identified the specific GM that is causally linked to DN in both T1DM and T2DM patients. Moreover, we identified distinct microbial changes in T1DN that differed from those seen in T2DN, offering valuable insights into GM signatures associated with subtype of nephropathy.