Gut microbiome-wide association study of depressive symptoms

The causal relationship between gut microbiota and preterm birth: a two-sample Mendelian randomization study

BACKGROUND

Preterm birth, a significant global health concern, has been associated with alterations in the gut microbiota. However, the causal nature of this relationship remains uncertain due to the limitations inherent in observational studies.

PURPOSE

To investigate the potential causal relationship between gut microbiota imbalances and preterm birth.

METHODS

We conducted a two-sample Mendelian randomization (MR) study using genome-wide association study (GWAS) data from the MiBioGen consortium focusing on microbiota and preterm birth. Single nucleotide polymorphisms (SNPs) associated with the microbiota were selected as instrumental variables. The inverse variance weighting (IVW) method was used to estimate causality. We confirmed pleiotropy and identified and excluded outlier SNPs using MR-PRESSO and MR-Egger regression. Cochran's Q test was applied to assess heterogeneity among SNPs, and a leave-one-out analysis was performed to evaluate the influence of individual SNPs on overall estimates.

RESULTS

Our findings provide evidence for a causal link between specific components of the gut microbiota and preterm birth, with the identification of relevant metabolites.

CONCLUSION

This study highlights the causal role of gut microbiota imbalances in preterm birth, offering novel insights into the development of preterm birth and potential targets for prevention strategies.

Effect of ultra-processed food consumption on the gut microbiota in the first year of life: Findings from the MINA-Brazil birth cohort study

BACKGROUND AND AIMS

The first years of life are fundamental for the establishment of the gut microbiota, with diet being one of the main early exposures. During this period, the beneficial effect of breastfeeding on modulating the gut microbiota is well known; however, there are important gaps in the literature on the effects of ultra-processed food (UPF) consumption, particularly in longitudinal and large sample designs. Through a prospective birth cohort study, we investigated the effects of UPF consumption on the gut microbiota of children during the first year of life.

METHODS

This study included children from the MINA-Brazil birth cohort with gut microbiota data (16S rRNA) available at the 1-year follow-up (n = 728). Data on breastfeeding practices were collected after childbirth and during follow-up visits. Complementary feeding was measured using a semi-structured questionnaire, referring to the day before the interview at the 1-year follow-up. A combined variable was generated according to breastfeeding practices and UPF consumption and was used as an independent variable in the adjusted median regression models, with alpha diversity parameters as the dependent variable. Beta diversity was analyzed using PERMANOVA according to Bray-Curtis dissimilarity and Distance-based Redundancy Analysis (db-RDA) adjusted for covariates. Relative abundance was analyzed using ANCOM-BC (corrected by FDR) and MaAsLin2 adjusted for covariates.

RESULTS

Weaned children who consumed UPF showed a significant increase in alpha diversity for all parameters in the median regression models (Observed ASVs: p = 0.005; Shannon index: p = 0.036; Chao index: p = 0.026; Simpson index: p = 0.012) and in beta diversity (PERMANOVA: p = 0.006; db-RDA: p < 0.001) compared to breastfed children who did not consume UPF. Breastfed children who did not consume UPF had a higher relative abundance of Bifidobacterium than weaned children who consumed UPF (both p < 0.001 for ANCOM-BC and MaAsLin2) and a lower relative abundance of Firmicutes (p < 0.001 for MaAsLin2), Blautia (both p < 0.001 for ANCOM-BC and MaAsLin2), Sellimonas (p = 0.008 for ANCOM-BC) and Finegoldia (p = 0.045 for MaAsLin2) than weaned children who consumed UPF.

CONCLUSION

These findings suggest that UPF consumption may negatively impact the diversity and abundance of the gut microbiota, with a more pronounced effect in children who have already been weaned.

The effect of mitochondrial-associated endoplasmic reticulum membranes (MAMs) modulation: New insights into therapeutic targets for depression

Depression is a prevalent mental disorder with high morbidity and mortality and its pathogenesis remains exactly unclarified. However, mitochondria and endoplasmic reticulum (ER) are two highly dynamic organelles that perform an indispensable role in the development of depression. Mitochondrial dysfunction and ER stress are recognized as vital pathological hallmarks in depression. The changes of intracellular activities such as mitochondrial dynamics, mitophagy, energy metabolism and ER stress are closely correlated with the progression of depression. Moreover, organelles interactions are conducive to homeostasis and cellular functions, and mitochondrial-associated endoplasmic reticulum membranes (MAMs) serve as signaling hubs of the two organelles and the coupling of the pathological progression. The main roles of MAMs are involved in metabolism, signal transduction, lipid transport, and maintenance of its structure and function. At present, accumulating studies elucidated that MAMs have gradually become a novel therapeutic target in treatment of depression. In the review, we focus on influence of mitochondria dysfunction and ER stress on depression. Furthermore, we discuss the underlying role of MAMs in depression and highlight natural products targeting MAMs as potential antidepressants to treat depression.

Nutritional Strategies in Major Depression Disorder: From Ketogenic Diet to Modulation of the Microbiota-Gut-Brain Axis

Major depressive disorder (MDD) is a leading cause of disability worldwide. While traditional pharmacological treatments are effective for many cases, a significant proportion of patients do not achieve full remission or experience side effects. Nutritional interventions hold promise as an alternative or adjunctive approach, especially for treatment-resistant depression. This review examines the potential role of nutrition in managing MDD through addressing biological deficits and modulating pathways relevant to its pathophysiology. Specifically, it explores the ketogenic diet and gut microbiome modulation through various methods, including probiotics, prebiotics, synbiotics, postbiotics, and fecal microbiota transplantation. Numerous studies link dietary inadequacies to increased MDD risk and deficiencies in nutrients like omega-3 s, vitamins D and B, magnesium, and zinc. These deficiencies impact neurotransmitters, inflammation, and other biological factors in MDD. The gut-brain axis also regulates mood, stress response, and immunity, and disruptions are implicated in MDD. While medications aid acute symptoms, nutritional strategies may improve long-term outcomes by preventing relapse and promoting sustained remission. This comprehensive review aims to provide insights into nutrition's multifaceted relationship with MDD and its potential for developing more effective integrated treatment approaches.

The joint and interactive effects of the non-high-density lipoprotein cholesterol to high-density lipoprotein cholesterol ratio (NHHR) and body mass index on the risk of depression, as well as the mediating role of NHHR: results from NHANES 2005-2023

BACKGROUND

Various research in the past has indicated that the NHHR, which represents the ratio of non-high-density lipoprotein cholesterol (non-HDL-C) to high-density lipoprotein cholesterol (HDL-C), and body mass index (BMI) each act independently as contributors to depression risk. Nonetheless, studies exploring the combination of NHHR with BMI in relation to depression are limited. Consequently, the central aim of this study is investigating the joint and interactive effects of NHHR and BMI on depression risk, as well as the mediating role of NHHR.

METHODS

Encompassing participants aged 20 years or over, this research incorporated a total of 39,704 individuals from the National Health and Nutrition Examination Survey (NHANES), which covered the period of 2005 to 2023. To analyze the impact of NHHR and its combination with BMI on depression, our analytical approach included multivariate logistic regression, restricted cubic spline modeling, interaction testing and subgroup analyses. Additionally, we studied the joint effects of NHHR and BMI. Finally, we applied a four-way decomposition analysis method to examine the interactions and mediating effects within the aforementioned relationships.

RESULTS

Among all participants in this study, the prevalence of depressive disorder (Patient Health Questionnaire-9 score ≥ 10) was 9.2%. Both the NHHR and BMI were associated with depression, which remained significant even after full adjustment for covariates [NHHR, OR (95% CI): 1.07 (1.04-1.09); BMI, OR (95% CI): 1.02 (1.02-1.03)]. Compared with the reference group, the OR (95% CI) for the highest groups of NHHR, BMI, and their product term NHHR-BMI were 1.41 (1.24-1.61), 1.35 (1.18-1.54), and 1.59 (1.37-1.84), respectively. Participants with NHHR in the fourth quartile and BMI exceeding 30 kg/m², had higher depression risk compared to other participants with NHHR in the first quartile and BMI below 25 kg/m² [OR (95% CI): 1.64 (1.34-2.00)]. Results of the four-way decomposition analyses indicated that NHHR played a mediating role in the association between BMI and depression, with the mediating effect accounting for 17.6%. Similarly, NHHR also mediated 11.0% of the mediating effect between BMI and PHQ-9 score. However, no interaction between NHHR and BMI related to depression was found in the general population. After stratifying by gender, it was found that the mediated interaction between NHHR and BMI had a statistically significant effect on depression and PHQ-9 score in males.

CONCLUSIONS

Depression risk is linked to both NHHR and BMI, and NHHR has a significant mediating impact on the association between BMI and depression. Notably, there is a non-negligible mediated interaction effect between BMI and NHHR in male participants. Compared to considering NHHR or BMI individually, participants had a higher risk of depression when the combined terms of the two were in the higher quartiles. These findings suggest that the combined assessment of these two indicators may help deepen the understanding and evaluation of depression, enhance the accuracy of risk stratification, and is worthy of further research.

Complete genome sequences of Sellimonas intestinalis JCM 30749T, Sellimonas caecigallum JCM 35759T, and Sellimonas catena JCM 35622T and JCM 35623

We obtained complete genome sequences of Sellimonas intestinalis JCM 30749T, "Sellimonas caecigallum" JCM 35759T, Sellimonas catena JCM 35622T, and Sellimonas catena JCM 35623. All four genomes consist of a single circular chromosome, with lengths of 2,758,996 to 3,825,976 base pairs and G + C contents of 45.12% to 45.59%.

Beyond weight loss: exploring the neurological ramifications of altered gut microbiota post-bariatric surgery

This review discusses findings related to neurological disorders, gut microbiota, and bariatric surgery, focusing on neurotransmitters, neuroendocrine, the pathophysiology of bacteria contributing to disorders, and possible therapeutic interventions. Research on neurotransmitters suggests that their levels are heavily influenced by gut microbiota, which may link them to neurological disorders such as Alzheimer's disease, Parkinson's disease, Multiple sclerosis, Depression, and Autism spectrum disorder. The pathophysiology of bacteria that reach and influence the central nervous system has been documented. Trends in microbiota are often observed in specific neurological disorders, with a prominence of pro-inflammatory bacteria and a reduction in anti-inflammatory types. Furthermore, bariatric surgery has been shown to alter microbiota profiles similar to those observed in neurological disorders. Therapeutic interventions, including fecal microbiota transplants and probiotics, have shown potential to alleviate neurological symptoms. We suggest a framework for future studies that integrates knowledge from diverse research areas, employs rigorous methodologies, and includes long-trial clinical control groups.

Differences in Gut Microbiota Composition Depending on the Site of Pain in Patients with Chronic Pain

Background

There are many factors associated with chronic pain, including changes in the nervous and musculoskeletal systems and so on. Recently, it has become clear that the gut microbiota (GM) influences these factors, and there are many reports of GM dysbiosis in patients with chronic pain. However, the relationship between pain and GM remains unclear. Our previous study reported that defecation status, which reflects GM composition, was associated with pain intensity and that this relationship was different for each pain site. Our study investigated the association between pain site and the GM composition of feces in chronic pain patients.

Methods

The subjects were 136 patients with chronic pain and 125 healthy controls. Patients were classified into four groups, whole body (WB) pain, lower back and lower extremity (LL) pain, headache, and upper back and upper extremity pain, based on the site of pain, and we investigated differences in GM taxonomy groups compared with healthy subject.

Results

Chronic pain patients had a lower alpha diversity (effect size=0.16, p=0.02). But each pain site group did not differ in alpha diversity. WB pain patients showed higher Eggerthellaceae (LDA=3.09, p<0.01) and lower Halomonas (LDA =-2.72, p<0.01). LL pain patients had increased Fusobacterium and Sellimonas (LDA=4.09,3.03 p<0.01, 0.01) but reduced Halomonas (LDA=-2.59, p<0.01), and other key taxa.

Conclusion

WB and LL patients may have GM compositions different from healthy controls, but larger studies are needed to confirm this.

Selenium Broussonetia papyrifera polysaccharide alleviated cyclophosphamide-induced immune suppression, growth inhibition, intestinal damage, and gut microbiota disorder in yellow-feather broilers

This study aims to investigate the effects of selenium Broussonetia papyrifera polysaccharide (Se-BPP) on growth performance, immune regulation, intestinal barrier function, and gut microbiota in cyclophosphamide (CTX)-induced immunosuppressed chicks. A total of 120 one-day-old male yellow-feathered broilers were randomly divided into five groups: normal control group (NC), model control group (MC), low-dose Se-BPP group (Se-L), high-dose Se-BPP group (Se-H), and Astragalus polysaccharide (APS) group The Se-L and Se-H groups were supplemented with 0.1 % or 0.2 % Se-BPP, respectively, while the APS group was supplemented with 0.2 % APS. On days 22, 24, and 26, the NC group received intramuscular injections of 80 mg/kg saline, while the other groups received the same dose of CTX to induce immunosuppression in the chicks. The results showed that CTX caused growth retardation, immunosuppression, intestinal damage, and alterations in gut microbiota structure. Supplementation with Se-BPP improved average daily gain and reduced feed-to-gain ratio, promoting growth in immunosuppressed chicks. Se-BPP increased the immune organ index and serum content of IgG, IgM, IgA, SOD, GSH-Px, CAT, IL-2, IL-4, IL-6, IL-10, and INF-γ, thus alleviating the immunosuppression and oxidative stress caused by CTX. Additionally, Se-BPP enhanced the mRNA expression levels of ZO-1, Claudin 1, and MUC2 and increased villus height in the jejunum, effectively mitigating intestinal damage induced by CTX. Although the effect of Se-BPP on alpha diversity of the gut microbiota was not significant, it increased the abundance of beneficial bacteria such as Ruminococcus and Lactobacillus. In brief, this study demonstrated that adding Se-BPP to the diet could improve immunosuppression, intestinal damage, and microbiota disturbances in yellow-feather broiler chickens challenged with CTX, enhancing their production performance.

Gut Microbiome, Diet and Depression: Literature Review of Microbiological, Nutritional and Neuroscientific Aspects

PURPOSE OF REVIEW

This review explores the intricate relationships among the gut microbiota, dietary patterns, and mental health, focusing specifically on depression. It synthesizes insights from microbiological, nutritional, and neuroscientific perspectives to understand how the gut-brain axis influences mood and cognitive function.

RECENT FINDINGS

Recent studies underscore the central role of gut microbiota in modulating neurological and psychological health via the gut-brain axis. Key findings highlight the importance of dietary components, including probiotics, prebiotics, and psychobiotics, in restoring microbial balance and enhancing mood regulation. Different dietary patterns exhibit a profound impact on gut microbiota composition, suggesting their potential as complementary strategies for mental health support. Furthermore, mechanisms like tryptophan metabolism, the HPA axis, and microbial metabolites such as SCFAs are implicated in linking diet and microbiota to depression. Clinical trials show promising effects of probiotics in alleviating depressive symptoms. This review illuminates the potential of diet-based interventions targeting the gut microbiota to mitigate depression and improve mental health. While the interplay between microbial diversity, diet, and brain function offers promising therapeutic avenues, further clinical research is needed to validate these findings and establish robust, individualized treatment strategies.

Microbiomic and Metabolomic Insights into the Mechanisms of Alfalfa Polysaccharides and Seaweed Polysaccharides in Alleviating Diarrhea in Pre-Weaning Holstein Calves

Neonatal calves' diarrhea, which can be severe enough to cause death, has a significant impact on the global cattle industry. In this study, alfalfa polysaccharides and seaweed polysaccharides were found to significantly improve the diarrhea condition in neonatal calves. To explore the underlying mechanisms, further microbiomic and metabolomic analyses were conducted. This study investigated the impact of alfalfa polysaccharides and seaweed polysaccharides on growth performance, serum metabolites, gut microbiota, and metabolomics in neonatal Holstein calves. A total of 24 newborn calves were randomly assigned to three groups, with 8 calves per treatment group. The control (CON) group was fed a basal diet, the alfalfa polysaccharide (AP) group received a basal diet supplemented with alfalfa polysaccharides (4 g/calf/day), and the seaweed polysaccharide group (SP) received a basal diet supplemented with seaweed polysaccharides (4 g/calf/day). These polysaccharides were plant extracts. Compared to the CON group, the results indicated that SP significantly enhanced the body weight, height, chest circumference, and average daily gain of Holstein calves (p < 0.05), while also reducing the diarrhea rate and improving manure scoring (p < 0.05). Compared to the CON, AP also reduced the diarrhea rate (p < 0.05). In terms of serum biochemistry, supplementation with AP and SP increased serum alkaline phosphatase (ALP) and insulin-like growth factor 1 (IGF-1) levels compared to the CON group (p < 0.05). Both AP and SP elevated serum catalase (CAT) and Total Antioxidant Capacity (T-AOC) levels, indicating enhanced antioxidant status (p < 0.05). Regarding immune responses, supplementation with AP and SP significantly increased serum complement component 3 (C3) and immunoglobulin M (IgM) levels, while significantly reducing pro-inflammatory cytokines interleukin-18 (IL-18), tumor necrosis factor alpha (TNF-α), and interferon-gamma (IFN-γ) compared to the CON group (p < 0.05). Microbiota analysis revealed that AP modulated the abundance of Firmicutes, while SP influenced the abundance of Prevotella and Succiniclasticum. AP and SP differentially influenced intestinal metabolites compared to the CON group, leading to enrichment in pathways related to immunity, antibacterial, and anti-inflammatory functions. These pathways included the biosynthesis of alkaloids from ornithine, lysine, and nicotinic acid, glucocorticoid and mineralocorticoid receptor canothersis/antagonists, secondary metabolite biosynthesis, and alkaloid biosynthesis from histidine and purine, thus alleviating intestinal inflammation. Therefore, by supplementing with AP and SP, the diarrhea rate in calves was reduced, and the immune function of Holstein calves was enhanced, while simultaneously promoting a higher relative abundance of beneficial gut bacteria and suppressing the relative abundance of pathogenic bacteria. Additionally, gut pathways associated with immune response and inflammation were modulated by AP and SP. This study provided valuable insights and theoretical underpinnings for the use of AP and SP in preventing diarrhea in neonatal calves.

Multimedia: multimodal mediation analysis of microbiome data

Mediation analysis has emerged as a versatile tool for answering mechanistic questions in microbiome research because it provides a statistical framework for attributing treatment effects to alternative causal pathways. Using a series of linked regressions, this analysis quantifies how complementary data relate to one another and respond to treatments. Despite these advances, existing software's rigid assumptions often result in users viewing mediation analysis as a black box. We designed the multimedia R package to make advanced mediation analysis techniques accessible, ensuring that statistical components are interpretable and adaptable. The package provides a uniform interface to direct and indirect effect estimation, synthetic null hypothesis testing, bootstrap confidence interval construction, and sensitivity analysis, enabling experimentation with various mediator and outcome models while maintaining a simple overall workflow. The software includes modules for regularized linear, compositional, random forest, hierarchical, and hurdle modeling, making it well-suited to microbiome data. We illustrate the package through two case studies. The first re-analyzes a study of the microbiome and metabolome of Inflammatory Bowel Disease patients, uncovering potential mechanistic interactions between the microbiome and disease-associated metabolites, not found in the original study. The second analyzes new data about the influence of mindfulness practice on the microbiome. The mediation analysis highlights shifts in taxa previously associated with depression that cannot be explained indirectly by diet or sleep behaviors alone. A gallery of examples and further documentation can be found at https://go.wisc.edu/830110.

IMPORTANCE

Microbiome studies routinely gather complementary data to capture different aspects of a microbiome's response to a change, such as the introduction of a therapeutic. Mediation analysis clarifies the extent to which responses occur sequentially via mediators, thereby supporting causal, rather than purely descriptive, interpretation. Multimedia is a modular R package with close ties to the wider microbiome software ecosystem that makes statistically rigorous, flexible mediation analysis easily accessible, setting the stage for precise and causally informed microbiome engineering.

Increased expression of ER stress, inflammasome activation, and mitochondrial biogenesis-related genes in peripheral blood mononuclear cells in major depressive disorder

A subset of major depressive disorder (MDD) is characterized by immune system dysfunction, but the intracellular origin of these immune changes remains unclear. Here we tested the hypothesis that abnormalities in endoplasmic reticulum (ER) stress, inflammasome activity and mitochondrial biogenesis contribute to the development of systemic inflammation in MDD. RT-qPCR was used to measure mRNA expression of key organellar genes from peripheral blood mononuclear cells (PBMCs) isolated from 186 MDD and 67 healthy control (HC) subjects. The comparative CT (2-ΔΔCT) method was applied to quantify mRNA expression using GAPDH as the reference gene. After controlling for age, sex, BMI, and medication status using linear regression models, expression of the inflammasome (NLRC4 and NLRP3) and the ER stress (XBP1u, XBP1s, and ATF4) genes was found to be significantly increased in the MDD versus the HC group. Sensitivity analyses excluding covariates yielded similar results. After excluding outliers, expression of the inflammasome genes was no longer statistically significant but expression of the ER stress genes (XBP1u, XBP1s, and ATF4) remained significant and the mitochondrial biogenesis gene, MFN2, was significantly increased in the MDD group. NLRC4 and MFN2 were positively correlated with serum C-reactive protein concentrations, while ASC trended significant. The altered expression of inflammasome activation, ER stress, and mitochondrial biogenesis pathway components suggest that dysfunction of these organelles may play a role in the pathogenesis of MDD.

Role of the gut microbiome in psychological symptoms associated with inflammatory bowel diseases

The brain-gut axis constitutes the basis for the bidirectional communication between the central nervous system and the gastrointestinal tract driven by neural, hormonal, metabolic, immunological, and microbial signals. Alterations in the gut microbiome composition as observed in inflammatory bowel diseases can modulate brain function and emerging empirical evidence has indicated that interactions among the brain-gut microbiome-axis seem to play a significant role in the pathogenesis of both inflammatory bowel diseases and psychiatric disorders and their comorbidity. Yet, the immunological and molecular mechanisms underlying the co-occurrence of inflammatory bowel diseases and psychological symptoms are still poorly understood. The aim of this narrative review is to highlight contemporary empirical findings supporting a pivotal role of the gut microbiome in the pathophysiology of highly prevalent neuropsychiatric symptoms in inflammatory bowel diseases such as fatigue, depression, and anxiety. Finally, we focus on microbiome modulation as potential treatment option for comorbid neuropsychiatric symptoms in immune-mediated diseases and especially in inflammatory bowel diseases. High-quality clinical trials are required to clarify how microbiome modulation through dietary interventions or probiotic, prebiotic or synbiotic treatment can be used clinically to improve mental health and thus quality of life of patients with inflammatory bowel diseases.

Impact of antidepressants on the composition of the gut microbiome: A systematic review and meta-analysis of in vivo studies

BACKGROUND

There is a growing body of evidence suggesting that antidepressant drugs (ADs) alter the gut microbiome of persons with depressive disorders. Herein, we aim to investigate the gut microbial profile of AD-treated animal models of depression (MoD) and persons with major depressive disorder (MDD).

METHODS

We conducted a systematic review and meta-analysis investigating the gut microbiome community-level diversity and relative abundance of microbial taxa in AD-treated animal MoD and persons with MDD.

RESULTS

24 human studies (898 participants) and 48 animal studies (849 subjects) were identified. Nonsignificant differences in gut microbial richness were observed between AD-treated and nonmedicated animals and humans. Beta diversity analysis in animals shows that AD intake is linked to a distinct gut microbial profile, a result not observed in humans. Consistent depletion of the genera Faecalibacterium and Parasutterella, along with enrichment of Bifidobacterium, was observed in AD-treated persons with MDD. In AD-treated animals, AD intake was associated with depletion of Flavobacterium and Adlercreutzia, and enrichment of Parabacteroides.

LIMITATIONS

The studies in our review were heterogeneous in their participant population, dietary intake, type of ADs used, length and dosing of AD treatment, and frequency and time of fecal sample collection.

CONCLUSION

ADs are associated with some changes to the gut microbiome. Future studies should evaluate the gut microbiome profiles between depressive disorder diagnoses that may reveal potential differences and predictors of AD response, as well as new combinatorial therapeutics with agents (e.g., specific-strain probiotic adjunctive treatment) that can ameliorate micro-composition gut dysbiosis.

Medication use is associated with distinct microbial features in anxiety and depression

This study investigated the relationship between gut microbiota and neuropsychiatric disorders (NPDs), specifically anxiety disorder (ANXD) and/or major depressive disorder (MDD), as defined by Diagnostic and Statistical Manual of Mental Disorders (DSM)-IV or V criteria. The study also examined the influence of medication use, particularly antidepressants and/or anxiolytics, classified through the Anatomical Therapeutic Chemical (ATC) Classification System, on the gut microbiota. Both 16S rRNA gene amplicon sequencing (16S) and shallow shotgun sequencing (WGS) were performed on DNA extracted from 666 fecal samples from the Tulsa-1000 and Neurocomputational Mechanisms of Affiliation and Personality Study Center for Biomedical Research Excellence (NeuroMAP CoBRE) cohorts. The results highlight the significant influence of medication use; antidepressant use is associated with significant differences in gut microbiota beta diversity and has a larger effect size than NPD diagnosis. Next, specific microbes were associated with ANXD and MDD, highlighting their potential for non-pharmacological intervention. Finally, the study demonstrated the capability of Random Forest classifiers to predict diagnoses of NPD and medication use from microbial profiles, suggesting a promising direction for the use of gut microbiota as biomarkers for NPD. Though the effect sizes were larger in females than males, similar trends emerged for both sexes. These findings encourage future research on the gut microbiota's role in NPD and its interactions with pharmacological treatments.

The Causal Role of Esophageal Cancer and Gut Microbiota: A Bidirectional Mendelian Randomization Study

AIMS

Gut microbiota are reported to be associated with the incidence and prognosis of Esophageal cancer (EC) but their genetic association is unclear. We carried out a bidirectional MR analysis to assess the causal relationship between EC and gut microbiota from fecal samples.

METHODS

The microbiome genome-wide association studies (GWAS) data of 18,340 individuals provided by MiBioGen consortium and the EC GWAS data (740 esophageal cancers cases and 372 016 controls) provided by UK Biobank were respectively utilized as exposure and/or outcome data. Reliable single nucleotide polymorphisms (SNPs) were obtained after rigorous screening. A bidirectional Mendelian randomization (MR) analysis was conducted using the inverse-variance weighted (IVW) method. The sensitivity analyses including the MR-Egger method, weighted median, weighed mode and leave-one-out method were performed to examine the stability, heterogeneity and pleiotropy of the results.

RESULTS

Forward MR analysis revealed the increase in abundance of the microbial trait by each standard deviation was associated with a higher risk of EC (Coprobacter (OR = 1.001,95%CI = 1.000-1.002, P = .0281, FDR = 0.0424); Ruminococcus1(OR = 1.001,95%CI = 1.000-1.002, P = .0318, FDR = 0.0424); Senegalimassilia (OR = 1.002,95%CI = 1.000-1.003, P = .0062, FDR = 0.0372); Veillonella (OR = 1.001,95%CI = 1.000-1.002, P = .0182, FDR = 0.0372)) or a lower risk of EC (Eubacterium oxidoreducens (OR = 0.999, 95%CI = 0.998-1.000, P = .0379, FDR = 00 433); Lachnospira (OR = 0.998,95%CI = 0.996-1.000, P = .0186, FDR = 0.0372); Romboutsia (OR = 0.999,95%CI = 0.998-1.000, P = .0482, FDR = 0.0482); Turicibacter (OR = 0.999,95%CI = 0.998-1.000, P = .0133, FDR = 0.0372)). Reverse MR analysis showed that genetic liability to EC was also causally linked toincreased susceptibility of changes in the gut microbiome (genera Eggerthella (Beta = 37.63,95%CI = 4.76-70.50, P = .0248, FDR = 0.0331); Coprococcus 2 (Beta = 23.90,95%CI = 1.65-46.15, P = .0353, FDR = 0.0353); Christensenellaceae R.7 (Beta = 22.75,95%CI = 4.22-41.28, P = .0161, FDR = 0.0322); Intestinimonas (Beta = -33.24,95%CI = -54.90-11.58, P = .0026, FDR = 0.0104)).

CONCLUSIONS

Our findings supported a bidirectionally causal relationship between gut microbiota and EC, implying the potential role of gut microbiota in preventing the occurrence and development of EC.

Lactobacillus rhamnosus: An emerging probiotic with therapeutic potential for depression

Depression, a complex psychological disorder, involves multiple biological pathways in its pathogenesis. In recent years, the gut-brain axis theory has provided novel insights into the pathogenesis of depression, particularly the crucial role of the gut microbiota in mood regulation. While there remains no universal consensus on the most efficacious strains for depression treatment, Lactobacillus rhamnosus has risen to prominence within the realm of probiotics for its potential to positively modulate depressive symptoms. This review preliminarily explores the clinical significance of Lactobacillus rhamnosus in the treatment of depression and summarizes the potential mechanisms by which Lactobacillus rhamnosus treats depression, including its regulation of gut microbiota, alterations in gene expression, improvement of intestinal barrier function, maintenance of neurotransmitter balance, suppression of inflammatory responses, modulation of the immune system, coping with oxidative stress, and optimization of metabolic processes. Future research needs to further explore these mechanisms and combine them with clinical research results to optimize treatment plans and provide more effective treatment options for patients with depression.

Affective symptoms in pregnancy are associated with the vaginal microbiome

BACKGROUND

Composition of the vaginal microbiome in pregnancy is associated with adverse maternal, obstetric, and child health outcomes. Therefore, identifying sources of individual differences in the vaginal microbiome is of considerable clinical and public health interest. The current study tested the hypothesis that vaginal microbiome composition during pregnancy is associated with an individual's experience of affective symptoms and stress exposure.

METHODS

Data were based on a prospective longitudinal study of a medically healthy community sample of 275 mother-infant pairs. Affective symptoms and stress exposure and select measures of associated biomarkers (diurnal salivary cortisol, serum measures of sex hormones) were collected at each trimester; self-report, clinical, and medical records were used to collect detailed data on socio-demographic factors and health behavior, including diet and sleep. Vaginal microbiome samples were collected in the third trimester (34-40 weeks) and characterized by 16S rRNA sequencing. Identified taxa were clustered into three community clusters (CC1-3) based on dissimilarity of vaginal microbiota composition.

RESULTS

Results indicate that depressive symptoms during pregnancy were reliably associated with individual taxa and CC3 in the third trimester. Prediction of functional potential from 16S taxonomy revealed a differential abundance of metabolic pathways in CC1-3 and individual taxa, including biosynthetic pathways for serotonin and dopamine. We did not find robust evidence linking symptom- and stress-related biomarkers and CCs.

CONCLUSIONS

Our results provide further evidence of how prenatal psychological distress during pregnancy alters the maternal-fetal microbiome ecosystem that may be important for understanding maternal and child health outcomes.

Gut microbiome-gut brain axis-depression: interconnection

OBJECTIVES

The relationship between the gut microbiome and mental health, particularly depression, has gained significant attention. This review explores the connection between microbial metabolites, dysbiosis, and depression. The gut microbiome, comprising diverse microorganisms, maintains physiological balance and influences health through the gut-brain axis, a communication pathway between the gut and the central nervous system.

METHODS

Dysbiosis, an imbalance in the gut microbiome, disrupts this axis and worsens depressive symptoms. Factors like diet, antibiotics, and lifestyle can cause this imbalance, leading to changes in microbial composition, metabolism, and immune responses. This imbalance can induce inflammation, disrupt neurotransmitter regulation, and affect hormonal and epigenetic processes, all linked to depression.

RESULTS

Microbial metabolites, such as short-chain fatty acids and neurotransmitters, are key to gut-brain communication, influencing immune regulation and mood. The altered production of these metabolites is associated with depression. While progress has been made in understanding the gut-brain axis, more research is needed to clarify causative relationships and develop new treatments. The emerging field of psychobiotics and microbiome-targeted therapies shows promise for innovative depression treatments by harnessing the gut microbiome's potential.

CONCLUSIONS

Epigenetic mechanisms, including DNA methylation and histone modifications, are crucial in how the gut microbiota impacts mental health. Understanding these mechanisms offers new prospects for preventing and treating depression through the gut-brain axis.

The effect of exercise on depression and gut microbiota: Possible mechanisms

Exercise can effectively prevent and treat depression and anxiety, with gut microbiota playing a crucial role in this process. Studies have shown that exercise can influence the diversity and composition of gut microbiota, which in turn affects depression through immune, endocrine, and neural pathways in the gut-brain axis. The effectiveness of exercise varies based on its type, intensity, and duration, largely due to the different changes in gut microbiota. This article summarizes the possible mechanisms by which exercise affects gut microbiota and how gut microbiota influences depression. Additionally, we reviewed literature on the effects of exercise on depression at different intensities, types, and durations to provide a reference for future exercise-based therapies for depression.

Gut microbiota dysbiosis promotes cognitive impairment via bile acid metabolism in major depressive disorder

Evidence suggests that complex interactions among the gut microbiome, metabolic abnormalities, and brain have important etiological and therapeutic implications in major depressive disorder (MDD). However, the influence of microbiome-gut-brain cross-talk on cognitive impairment in MDD remains poorly characterized. We performed serum metabolomic profiling on 104 patients with MDD and 77 healthy controls (HCs), and also performed fecal metagenomic sequencing on a subset of these individuals, including 79 MDD patients and 60 HCs. The findings were validated in a separate cohort that included 40 patients with MDD and 40 HCs using serum-targeted metabolomics. Abnormal bile acid metabolism was observed in patients with MDD, which is related to cognitive dysfunction. The following gut microbiota corresponded to changes in bile acid metabolism and enzyme activities involved in the bile acid metabolic pathway, including Lachnospiraceae (Blautia_massiliensis, Anaerostipes_hadrus, Dorea_formicigenerans, and Fusicatenibacter_saccharivorans), Ruminococcaceae (Ruminococcus_bromii, Flavonifractor_plautii, and Ruthenibacterium_lactatiformans), and Escherichia_coli. Furthermore, a combinatorial marker classifier that robustly differentiated patients with MDD from HCs was identified. In conclusion, this study provides insights into the gut-brain interactions in the cognitive phenotype of MDD, indicating a potential therapeutic strategy for MDD-associated cognitive impairment by targeting the gut microbiota and bile acid metabolism.

Gut Microbiome Modulation of Glutamate Dynamics: Implications for Brain Health and Neurotoxicity

The gut-brain axis plays an integral role in maintaining overall health, with growing evidence suggesting its impact on the development of various neuropsychiatric disorders, including depression. This review explores the complex relationship between gut microbiota and glutamate (Glu) regulation, highlighting its effect on brain health, particularly in the context of depression following certain neurological insults. We discuss how microbial populations can either facilitate or limit Glu uptake, influencing its bioavailability and predisposing to neuroinflammation and neurotoxicity. Additionally, we examine the role of gut metabolites and their influence on the blood-brain barrier and neurotransmitter systems involved in mood regulation. The therapeutic potential of microbiome-targeted interventions, such as fecal microbiota transplantation, is also highlighted. While much research has explored the role of Glu in major depressive disorders and other neurological diseases, the contribution of gut microbiota in post-neurological depression remains underexplored. Future research should focus on explaining the mechanisms linking the gut microbiota to neuropsychiatric outcomes, particularly in conditions such as post-stroke depression, post-traumatic brain-injury depression, and epilepsy-associated depression. Systematic reviews and human clinical studies are needed to establish causal relationships and assess the efficacy of microbiome-targeted therapies in improving the neuropsychiatric sequalae after neurological insults.

Dynamic human gut microbiome and immune shifts during an immersive psychosocial intervention program

BACKGROUND

Although depression is a leading cause of disability worldwide, the pathophysiological mechanisms underlying this disorder-particularly those involving the gut microbiome-are poorly understood.

METHOD

To investigate, we conducted a community-based observational study to explore complex associations between changes in the gut microbiome, cytokine levels, and depression symptoms in 51 participants (Mage = 49.56, SD = 13.31) receiving an immersive psychosocial intervention. A total of 142 multi-omics samples were collected from participants before, during, and three months after the nine-day inquiry-based stress reduction program.

RESULTS

Results revealed that depression was associated with both an increased presence of putatively pathogenic bacteria and reduced microbial beta-diversity. Following the intervention, we observed reductions in neuroinflammatory cytokines and improvements in several mental health indicators. Interestingly, participants with a Prevotella-dominant microbiome showed milder symptoms when depressed, along with a more resilient microbiome and more favorable inflammatory cytokine profile, including reduced levels of CXCL-1.

CONCLUSIONS

These findings reveal a potentially protective link between the Prevotella-dominant microbiome and depression, as evidenced by a reduced pro-inflammatory environment and fewer depressive symptoms. These insights, coupled with observed improvements in neuroinflammatory markers and mental health from the intervention, may highlight potential avenues for microbiome-targeted therapies for managing depression.

The blood metabolome of cognitive function and brain health in middle-aged adults - influences of genes, gut microbiome, and exposome

Increasing evidence suggests the involvement of metabolic alterations in neurological disorders, including Alzheimer's disease (AD), and highlights the significance of the peripheral metabolome, influenced by genetic factors and modifiable environmental exposures, for brain health. In this study, we examined 1,387 metabolites in plasma samples from 1,082 dementia-free middle-aged participants of the population-based Rotterdam Study. We assessed the relation of metabolites with general cognition (G-factor) and magnetic resonance imaging (MRI) markers using linear regression and estimated the variance of these metabolites explained by genes, gut microbiome, lifestyle factors, common clinical comorbidities, and medication using gradient boosting decision tree analysis. Twenty-one metabolites and one metabolite were significantly associated with total brain volume and total white matter lesions, respectively. Fourteen metabolites showed significant associations with G-factor, with ergothioneine exhibiting the largest effect (adjusted mean difference = 0.122, P = 4.65×10-7). Associations for nine of the 14 metabolites were replicated in an independent, older cohort. The metabolite signature of incident AD in the replication cohort resembled that of cognition in the discovery cohort, emphasizing the potential relevance of the identified metabolites to disease pathogenesis. Lifestyle, clinical variables, and medication were most important in determining these metabolites' blood levels, with lifestyle, explaining up to 28.6% of the variance. Smoking was associated with ten metabolites linked to G-factor, while diabetes and antidiabetic medication were associated with 13 metabolites linked to MRI markers, including N-lactoyltyrosine. Antacid medication strongly affected ergothioneine levels. Mediation analysis revealed that lower ergothioneine levels may partially mediate negative effects of antacids on cognition (31.5%). Gut microbial factors were more important for the blood levels of metabolites that were more strongly associated with cognition and incident AD in the older replication cohort (beta-cryptoxanthin, imidazole propionate), suggesting they may be involved later in the disease process. The detailed results on how multiple modifiable factors affect blood levels of cognition- and brain imaging-related metabolites in dementia-free participants may help identify new AD prevention strategies.

Intricate mechanism of anxiety disorder, recognizing the potential role of gut microbiota and therapeutic interventions

Anxiety is a widespread psychological disorder affecting both humans and animals. It is a typical stress reaction; however, its longer persistence can cause severe health disorders affecting the day-to-day life activities of individuals. An intriguing facet of the anxiety-related disorder can be addressed better by investigating the role of neurotransmitters in regulating emotions, provoking anxiety, analyzing the cross-talks between neurotransmitters, and, most importantly, identifying the biomarkers of the anxiety. Recent years have witnessed the potential role of the gut microbiota in human health and disorders, including anxiety. Animal models are commonly used to study anxiety disorder as they offer a simpler and more controlled environment than humans. Ultimately, developing new strategies for diagnosing and treating anxiety is of paramount interest to medical scientists. Altogether, this review article shall highlight the intricate mechanisms of anxiety while emphasizing the emerging role of gut microbiota in regulating metabolic pathways through various interaction networks in the host. In addition, the review will foster information about the therapeutic interventions of the anxiety and related disorder.

Exploring the Potential of Probiotics and Prebiotics in Major Depression: From Molecular Function to Clinical Therapy

Major depressive disorder (MDD) represents a complex and challenging mental health condition with multifaceted etiology. Recent research exploring the gut-brain axis has shed light on the potential influence of gut microbiota on mental health, offering novel avenues for therapeutic intervention. This paper reviews current evidence on the role of prebiotics and probiotics in the context of MDD treatment. Clinical studies assessing the effects of prebiotic and probiotic interventions have demonstrated promising results, showcasing improvements in depression symptoms and metabolic parameters in certain populations. Notably, prebiotics and probiotics have shown the capacity to modulate inflammatory markers, cortisol levels, and neurotransmitter pathways linked to MDD. However, existing research presents varied outcomes, underscoring the need for further investigation into specific microbial strains, dosage optimization, and long-term effects. Future research should aim at refining personalized interventions, elucidating mechanisms of action, and establishing standardized protocols to integrate these interventions into clinical practice. While prebiotics and probiotics offer potential adjunctive therapies for MDD, continued interdisciplinary efforts are vital to harnessing their full therapeutic potential and reshaping the landscape of depression treatment paradigms.

A Multi-Enzyme Complex That Mitigates Hepatotoxicity, Improves Egg Production and Quality, and Enhances Gut and Liver Health in Laying Hens Exposed to Trace Aflatoxin B1

Aflatoxin B1 is a prevalent secondary hazardous metabolite generated by fungus present in feed ingredients and the surrounding environment: enzymes are currently being recognized as an efficient and promising approach to reducing the associated risks. The objective of this study was to assess the effects of varying doses of enzyme complexes on several parameters in laying hens that were exposed to aflatoxin. During an 8-week experiment, a total of 288 Yukou Jingfen No.6 laying hens were placed into four groups. These groups included a group treated with toxins (CON group) and groups supplemented with compound enzyme complexes at doses of 250 g/t (E1 group), 500 g/t (E2 group), and 1000 g/t (E3 group). The E2 and E3 groups exhibited a statistically significant 2.6% increase in egg production rate compared to the CON group (p < 0.05). In addition, the E2 group showed significant improvements in both the feed-to-egg ratio and egg weight (p < 0.05). In addition, the E2 and E3 groups showed improved hutch unit and egg white height compared to the control group (p < 0.05). The E2 and E3 groups showed a substantial rise in liver health indicators, namely serum alanine transaminase (ALT) and alkaline phosphatase (ALP) activity. On the other hand, malondialdehyde (MDA) was lowered, and total superoxide dismutase (T-SOD) and total antioxidant capacity (T-AOC) were raised. These findings were statistically significant (p < 0.05). The E2 and E3 groups showed notable enhancements in intestinal morphology, as evidenced by a rise in villus height and a decrease in crypt depth in all segments of the intestine (p < 0.05). Furthermore, analysis of 16S rRNA sequencing revealed that these participants had a higher prevalence and variety of microorganisms in their gut microbiota. More precisely, there was a significant rise in the abundance of Bacteroidota and a decline in Firmicutes at the level of the phylum. In general, the inclusion of the enzyme complex had advantageous impacts on performance, egg quality, intestinal morphology, intestinal barrier function, and intestinal flora in laying hens. Our results indicate that toxin-degrading enzymes, when used as feed additives, play a significant role in mitigating AFB1 contamination in diets and improving the production performance of laying hens.

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 the 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, who were 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.

Unlocking gut-liver-brain axis communication metabolites: energy metabolism, immunity and barriers

The interaction between the gut-microbiota-derived metabolites and brain has long been recognized in both health and disease. The liver, as the primary metabolic organ for nutrients in animals or humans, plays an indispensable role in signal transduction. Therefore, in recent years, Researcher have proposed the Gut-Liver-Brain Axis (GLBA) as a supplement to the Gut-Brain Axis. The GLBA plays a crucial role in numerous physiological and pathological mechanisms through a complex interplay of signaling pathways. However, gaps remain in our knowledge regarding the developmental and functional influences of the GLBA communication pathway. The gut microbial metabolites serve as communication agents between these three distant organs, functioning prominently within the GLBA. In this review, we provide a comprehensive overview of the current understanding of the GLBA, focusing on signaling molecules role in animal and human health and disease. In this review paper elucidate its mechanisms of communication, explore its implications for immune, and energy metabolism in animal and human, and highlight future research directions. Understanding the intricate communication pathways of the GLBA holds promise for creating innovative treatment approaches for a wide range of immune and metabolic conditions.

The saNeuroGut Initiative: Investigating the Gut Microbiome and Symptoms of Anxiety, Depression, and Posttraumatic Stress

INTRODUCTION

Common mental disorders, such as anxiety disorders, depression, and posttraumatic stress disorder (PTSD), present a substantial health and economic burden. The gut microbiome has been associated with these psychiatric disorders via the microbiome-gut-brain axis. However, previous studies have focused on the associations between the gut microbiome and common mental disorders in European, North American, and Asian populations. As part of the saNeuroGut Initiative, we assessed associations between gut microbial composition and self-reported symptoms of anxiety, depression, and posttraumatic stress (PTS) among South African adults.

METHODS

Participants completed validated, online self-report questionnaires to evaluate symptoms of state anxiety, trait anxiety, depression, and PTSD. Eighty-six stool-derived microbial DNA samples underwent sequencing of the V4 region of the 16S rRNA gene to characterise gut bacterial taxa in the sample.

RESULTS

No significant associations were observed between symptom severity scores and alpha (Shannon and Simpson indices) and beta (Aitchison distances) diversity metrics. Linear regression models revealed that the abundances of Catenibacterium, Collinsella, and Holdemanella were significantly positively associated with the severity of PTS symptoms.

CONCLUSION

Catenibacterium, Collinsella, and Holdemanella have each previously been associated with various psychiatric disorders, with Catenibacterium having been positively associated with symptoms of PTSD in another South African cohort. This study sheds light on the relationship between the human gut microbiome and symptoms of anxiety, depression, and PTS in a South African adult sample.

Faecal microbiota composition and impulsivity in a cohort of older adults with metabolic syndrome

Impulsivity is an important determinant of human behaviour, affecting self-control, reasonable thinking and food choices. Recent evidence suggests a role for gut microbiota in human behaviour, but the relationship between gut microbiota and impulsive behaviours remains largely unexplored. To address this knowledge gap, the present study aims to explore the associations between faecal microbiota composition with trait and behavioural impulsivity, in a subcohort of the PREDIMED-Plus trial, including older adults presenting overweight/obesity. Fecal samples (n = 231) were profiled for their microbiota composition using 16 S rRNA amplicon sequencing and impulsivity was determined through four different assessments. Adherence to different dietary patterns was estimated through questionnaires. Beta diversity analyses showed a significant association with the Conner's Performance Test (CPT) in multivariate-adjusted models, and, in total, 13 bacterial genera associated with CPT. Erysipelotrichaceae UCG 003 showed the highest association with CPT and known butyrate producers such as Butyricicoccus spp., Roseburia spp., and Eubacterium hallii were among the identified bacteria. The bacteria Lachnospiraceae UCG 001, Anaerostipes and Blautia were associated with CPT and also the adherence to healthy and unhealthy plant-based diets. In addition, functional analysis showed a significant negative association between the CPT and the glucuronate and galacturonate metabolic pathways. From the other impulsivity assessments, two more associations were identified, for the genus Phascolarctobacterium with the Stroop test, and the genus Lachnospiraceae GAG 54 with the positive urgency subscore of UPPS-P Impulsive Behaviour Scale. Overall, our findings suggest potential links between the faecal microbiota composition and function with behavioural impulsive inattention as determined by the CPT.

Multi-omics insights implicate the remodeling of the intestinal structure and microbiome in aging

Background

Aging can impair the ability of elderly individuals to fight infections and trigger persistent systemic inflammation, a condition known as inflammaging. However, the mechanisms underlying the development of inflammaging remain unknown.

Methods

We conducted 16S rRNA sequencing of intestinal contents from young and old C57BL/6J mice to elucidate changes in gut microbiota diversity and microbial community composition after aging. Aging-related differential bacterial taxa were then identified, and their abundance trends were validated in human samples. The variances in intestinal barrier function and circulating endotoxin between groups were also assessed. Furthermore, widely targeted metabolomics was conducted to characterize metabolic profiles after aging and to investigate the key metabolic pathways enriched by the differential metabolites.

Results

Our findings demonstrated an increase in relative proportion of pathogenic bacteria with age, a trend also revealed in healthy populations of different age groups. Additionally, aging individuals exhibited reduced intestinal barrier function and increased circulating endotoxin levels. Widely targeted metabolomics revealed a significant increase in various secondary bile acid metabolites after aging, positively correlated with the relative abundance of several aging-related bacterial taxa. Furthermore, old group had lower levels of various anti-inflammatory or beneficial metabolites. Enrichment analysis identified the starch and sucrose metabolism pathway as potentially the most significantly impacted signaling pathway during aging.

Conclusion

This study aimed to provide insights into the complex interactions involved in organismal inflammaging through microbial multi-omics. These findings lay a solid foundation for future research aimed at identifying novel biomarkers for the clinical diagnosis of aging-related diseases or potential therapeutic targets.

Multiplatform metabolomic interlaboratory study of a whole human stool candidate reference material from omnivore and vegan donors

INTRODUCTION

Human metabolomics has made significant strides in understanding metabolic changes and their implications for human health, with promising applications in diagnostics and treatment, particularly regarding the gut microbiome. However, progress is hampered by issues with data comparability and reproducibility across studies, limiting the translation of these discoveries into practical applications.

OBJECTIVES

This study aims to evaluate the fit-for-purpose of a suite of human stool samples as potential candidate reference materials (RMs) and assess the state of the field regarding harmonizing gut metabolomics measurements.

METHODS

An interlaboratory study was conducted with 18 participating institutions. The study allowed for the use of preferred analytical techniques, including liquid chromatography-mass spectrometry (LC-MS), gas chromatography-mass spectrometry (GC-MS), and nuclear magnetic resonance (NMR).

RESULTS

Different laboratories used various methods and analytical platforms to identify the metabolites present in human stool RM samples. The study found a 40% to 70% recurrence in the reported top 20 most abundant metabolites across the four materials. In the full annotation list, the percentage of metabolites reported multiple times after nomenclature standardization was 36% (LC-MS), 58% (GC-MS) and 76% (NMR). Out of 9,300 unique metabolites, only 37 were reported across all three measurement techniques.

CONCLUSION

This collaborative exercise emphasized the broad chemical survey possible with multi-technique approaches. Community engagement is essential for the evaluation and characterization of common materials designed to facilitate comparability and ensure data quality underscoring the value of determining current practices, challenges, and progress of a field through interlaboratory studies.

Randomised control trial indicates micronutrient supplementation may support a more robust maternal microbiome for women with antenatal depression during pregnancy

BACKGROUND AND AIMS

We investigated the effects of high dose dietary micronutrient supplementation or placebo on the human gut microbiome in pregnant women who had moderate symptoms of antenatal depression. There is a significant absence of well-controlled clinical studies that have investigated the dynamic changes of the microbiome during pregnancy and the relationship among diet, microbiome and antenatal depression. This research is among the first to provide an insight into this area of research.

METHODS

This 12 - week study followed a standard double blinded randomised placebo-controlled trial (RCT) design with either high dose micronutrients or active placebo. Matching stool microbiome samples and mood data were obtained at baseline and post-treatment, from participants between 12 and 24 weeks gestation. Stool microbiome samples from 33 participants (17 in the placebo and 16 in the treatment group) were assessed using 16s rRNA sequencing. Data preparation and statistical analysis was predominantly performed using the QIIME2 bioinformatic software tools for 16s rRNA analysis.

RESULTS

Microbiome community structure became increasingly heterogenous with decreased diversity during the course of the study, which was represented by significant changes in alpha and beta diversity. This effect appeared to be mitigated by micronutrient administration. There were less substantial changes at the genus level, where Coprococcus decreased in relative abundance in response to micronutrient administration. We also observed that a higher abundance of Coprococcus and higher alpha diversity correlated with higher antenatal depression scores.

CONCLUSIONS

Micronutrient treatment appeared to support a more diverse (alpha diversity) and stable (beta diversity) microbiome during pregnancy. This may aid in maintaining a more resilient or adaptable microbial community, which would help protect against decreases or fluctuations that are observed during pregnancy.

A systematic and comprehensive review of the role of microbiota in urinary chronic pelvic pain syndrome

BACKGROUND

Many genitourinary tract disorders could be attributed partly to the microbiota. This study sought to conduct a systematic review of the role of the microbiota in urinary chronic pelvic pain syndrome (UCPPS).

METHODS

We searched Embase, Scopus, Web of Science, and PubMed with no time, language, or study type restrictions until December 1, 2023. The JBI Appraisal Tool was used to assess the quality of the studies. Study selection followed the PRISMA statement. Studies addressing microbiome variations among patients suffering from interstitial cystitis/bladder pain syndrome (IC/BPS) or chronic prostatitis/chronic pelvic pain syndrome (CP/CPPS) and a control group were considered eligible.

RESULTS

A total of 21 studies (1 UCPPS, 12 IC/BPS, and 8 CP/CPPS) comprising 1125 patients were enrolled in our final data synthesis. It has been shown that the reduced diversity and discrepant composition of the gut microbiota may partly be attributed to the UCPPS pathogenesis. In terms of urine microbiota, some operational taxonomic units were shown to be elevated, while others became less abundant. Furthermore, various bacteria and fungi are linked to specific clinical features. Few investigations denied UCPPS as a dysbiotic condition.

CONCLUSIONS

Urinary and intestinal microbiota appear to be linked with UCPPS, comprising IC/BPS and CP/CPPS. However, given the substantial disparity of published studies, a battery of prospective trials is required to corroborate these findings.

Baseline gut microbiome as a predictive biomarker of response to probiotic adjuvant treatment in gout management

Gout is characterized by dysregulation of uric acid (UA) metabolism, and the gut microbiota may serve as a regulatory target. This two-month randomized, double-blind, placebo-controlled trial aimed to investigate the additional benefits of coadministering Probio-X alongside febuxostat. A total of 160 patients with gout were randomly assigned to either the probiotic group (n = 120; Probio-X [3 × 1010 CFU/day] with febuxostat) or the placebo group (n = 40; placebo material with febuxostat). Coadministration of Probio-X significantly decreased serum UA levels and the rate of acute gout attacks (P < 0.05). Based on achieving a target sUA level (360 μmol/L) after the intervention, the probiotic group was further subdivided into probiotic-responsive (ProA; n = 54) and probiotic-unresponsive (ProB; n = 66) subgroups. Post-intervention clinical indicators, metagenomic, and metabolomic changes in the ProB and placebo groups were similar, but differed from those in the ProA group, which exhibited significantly lower levels of acute gout attack, gout impact score, serum indicators (UA, XOD, hypoxanthine, and IL-1β), and fecal gene abundances of UA-producing pathways (KEGG orthologs of K13479 and K01487; gut metabolic modules for formate conversion and lactose and galactose degradation). Additionally, the ProA group showed significantly higher levels (P < 0.05) of gut SCFAs-producing bacteria and UA-related metabolites (xanthine, hypoxanthine, bile acids) after the intervention. Finally, we established a gout metagenomic classifier to predict probiotic responsiveness based on subjects' baseline gut microbiota composition. Our results indicate that probiotic-driven therapeutic responses are highly individual, with the probiotic-responsive cohort benefitting significantly from probiotic coadministration.

Gut Microbiome in Impulsively Violent Female Convicts

INTRODUCTION

Impulsivity and aggression are often interlinked behavioral traits that have major implications for our society. Therefore, the study of this phenomenon and derivative interventions that could lead to better control of impulsive aggression are of interest.

METHODS

We analyzed the composition and diversity of the gut bacterial microbiome of 33 impulsively violent female convicts with dissocial personality disorder and 20 non-impulsive age-matched women. Further, levels of assorted neurotransmitters and short-chain fatty acids (SCFAs) were analyzed in serum and stool samples. We also assessed all participants using a battery of psychological questionnaires and tested possible correlations between the collected clinical data and the composition and diversity of their microbiomes and metabolites.

RESULTS

We identified four bacterial amplicon sequencing variants that were differentially abundant in non-impulsive versus impulsive women - the genera Bacteroides, Barnesiella, and the order Rhodospirillales were more abundant in impulsive women. In contrast, the genus Catenisphaera was more abundant in non-impulsive women. Fecal tryptophan levels were significantly higher in impulsive women. Association analysis revealed a strong positive intercorrelation between most fecal SCFAs in the entire dataset.

CONCLUSIONS

Our study demonstrated possible associations between gut microbiomes and their metabolites and impulsive behavior in a unique cohort of prisoners convicted of violent assaults and a matched group of non-impulsive women from the same prison. Genus Bacteroides, which was differentially abundant in the two groups, encoded enzymes that affect serotonin pathways and could contribute to this maladaptive behavior. Similarly, increased fecal tryptophan levels in impulsive individuals could affect neuronal circuits in the brain.

INTRODUCTION

Impulsivity and aggression are often interlinked behavioral traits that have major implications for our society. Therefore, the study of this phenomenon and derivative interventions that could lead to better control of impulsive aggression are of interest.

METHODS

We analyzed the composition and diversity of the gut bacterial microbiome of 33 impulsively violent female convicts with dissocial personality disorder and 20 non-impulsive age-matched women. Further, levels of assorted neurotransmitters and short-chain fatty acids (SCFAs) were analyzed in serum and stool samples. We also assessed all participants using a battery of psychological questionnaires and tested possible correlations between the collected clinical data and the composition and diversity of their microbiomes and metabolites.

RESULTS

We identified four bacterial amplicon sequencing variants that were differentially abundant in non-impulsive versus impulsive women - the genera Bacteroides, Barnesiella, and the order Rhodospirillales were more abundant in impulsive women. In contrast, the genus Catenisphaera was more abundant in non-impulsive women. Fecal tryptophan levels were significantly higher in impulsive women. Association analysis revealed a strong positive intercorrelation between most fecal SCFAs in the entire dataset.

CONCLUSIONS

Our study demonstrated possible associations between gut microbiomes and their metabolites and impulsive behavior in a unique cohort of prisoners convicted of violent assaults and a matched group of non-impulsive women from the same prison. Genus Bacteroides, which was differentially abundant in the two groups, encoded enzymes that affect serotonin pathways and could contribute to this maladaptive behavior. Similarly, increased fecal tryptophan levels in impulsive individuals could affect neuronal circuits in the brain.

Microbiota-gut-brain axis: Natural antidepressants molecular mechanism

BACKGROUND

Major depressive disorder (MDD) is a severe mental health condition characterized by persistent depression, impaired cognition, and reduced activity. Increasing evidence suggests that gut microbiota (GM) imbalance is closely linked to the emergence and advancement of MDD, highlighting the potential significance of regulating the "Microbiota-Gut-Brain" (MGB) axis to impact the development of MDD. Natural products (NPs), characterized by broad biological activities, low toxicity, and multi-target characteristics, offer unique advantages in antidepressant treatment by regulating MGB axis.

PURPOSE

This review was aimed to explore the intricate relationship between the GM and the brain, as well as host responses, and investigated the mechanisms underlying the MGB axis in MDD development. It also explored the pharmacological mechanisms by which NPs modulate MGB axis to exert antidepressant effects and addressed current research limitations. Additionally, it proposed new strategies for future preclinical and clinical applications in the MDD domain.

METHODS

To study the effects and mechanism by which NPs exert antidepressant effects through mediating the MGB axis, data were collected from Web of Science, PubMed, ScienceDirect from initial establishment to March 2024. NPs were classified and summarized by their mechanisms of action.

RESULTS

NPs, such as flavonoids,alkaloids,polysaccharides,saponins, terpenoids, can treat MDD by regulating the MGB axis. Its mechanism includes balancing GM, regulating metabolites and neurotransmitters such as SCAFs, 5-HT, BDNF, inhibiting neuroinflammation, improving neural plasticity, and increasing neurogenesis.

CONCLUSIONS

NPs display good antidepressant effects, and have potential value for clinical application in the prevention and treatment of MDD by regulating the MGB axis. However, in-depth study of the mechanisms by which antidepressant medications affect MGB axis will also require considerable effort in clinical and preclinical research, which is essential for the development of effective antidepressant treatments.

The interplay of gut microbiota, obesity, and depression: insights and interventions

The gut microbiome, body weight, and related comorbidities are intricately linked through a complex interaction of microbial, genetic, environmental, and psychological factors. Alterations in gut microbiota can contribute to the development of weight disorders and depressive symptoms, with the potential for these relationships to be bidirectional. Effective management of these interconnected conditions often involves a combination of lifestyle modifications and psychological support. Medical interventions, including treatments for obesity, antidiabetic drugs, antidepressants, antibiotics, and probiotics, can have beneficial and detrimental effects on gut microbiota and mental health. Further research is needed to better understand their impact on gut microbiome and mental health in the context of obesity.

Fecal fermentation behaviors of Konjac glucomannan and its impacts on human gut microbiota

Dietary fiber targets the regulation of the intestinal flora and thus affects host health, however, the complex relationship between these factors lacks direct evidence. In this study, the regulatory effects of Konjac glucomannan (KGM) on key metabolites of host intestinal flora were examined by using in vitro fermentation. The results showed that KGM could be utilized by the intestinal flora, which inhibited the relative abundance of Paeniclostridium, Lachnoclostridium, Phascolarctobacterium, and Bacteroides and enriched the relative abundance of Desulfovibrio, Sutterella, etc. Fermentation is accompanied by the production of short-chain acids, including acetic and propionic acids. Metabolomics revealed that KGM significantly promoted amino acid metabolism, lipid metabolism, and the biosynthesis of other secondary metabolites. Correlation analysis results showed that the increase of panose and N-(1-carboxy-3-carboxanilidopropyl) alanylproline content was positively correlated with the relative abundance of Megamonas. These results provide evidence that KGM affects host health by regulating gut microbiota and its metabolites.

Gut microbial and human genetic signatures of inflammatory bowel disease increase risk of comorbid mental disorders

The high prevalence of comorbid mental disorders (CMDs) in patients with inflammatory bowel disease (IBD) is well-documented. This study delves into the intricate CMD-IBD relationship through comprehensive analyses using human variants, gut microbiome, and anxiety/depression estimates from a cohort of 507 IBD patients and 75 controls. Notably, patients with IBD, especially those with CMD, exhibited lower diversity than controls. We identified 106 differentially abundant taxa (DATs) in IBD patients compared to controls and 21 DATs distinguishing CMD-affected from CMD-free IBD patients. Microbial IBD-risk scores, reflecting an individual's microbial burden for IBD, revealed a significant enrichment of IBD-risk signatures in CMD-affected patients compared to CMD-free patients. Additionally, there was an IBD-risk variant potentially regulating the abundance of an IBD/CMD-associated DAT, suggesting an interplay between IBD-risk variants and dysbiosis in CMD. Our investigation underscores the pivotal role of IBD-associated gut dysbiosis in predisposing IBD patients to CMD, partially through genetic variant-mediated mechanisms.

The potential of including the microbiome as biomarker in population-based health studies: methods and benefits

The key role of our microbiome in influencing our health status, and its relationship with our environment and lifestyle or health behaviors, have been shown in the last decades. Therefore, the human microbiome has the potential to act as a biomarker or indicator of health or exposure to health risks in the general population, if information on the microbiome can be collected in population-based health surveys or cohorts. It could then be associated with epidemiological participant data such as demographic, clinical or exposure profiles. However, to our knowledge, microbiome sampling has not yet been included as biological evidence of health or exposure to health risks in large population-based studies representative of the general population. In this mini-review, we first highlight some practical considerations for microbiome sampling and analysis that need to be considered in the context of a population study. We then present some examples of topics where the microbiome could be included as biological evidence in population-based health studies for the benefit of public health, and how this could be developed in the future. In doing so, we aim to highlight the benefits of having microbiome data available at the level of the general population, combined with epidemiological data from health surveys, and hence how microbiological data could be used in the future to assess human health. We also stress the challenges that remain to be overcome to allow the use of this microbiome data in order to improve proactive public health policies.

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.

Gut microbiota causally impacts adrenal function: a two-sample mendelian randomization study

Some studies have reported that the gut microbiota can influence adrenal-related hormone levels. However, the causal effects of the gut microbiota on adrenal function remain unknown. Therefore, we employed a two-sample Mendelian randomization (MR) study to systematically investigate the impact of gut microbiota on the function of different regions of the adrenal gland. The summary statistics for gut microbiota and adrenal-related hormones used in the two-sample MR analysis were derived from publicly available genome-wide association studies (GWAS). In the MR analysis, inverse variance weighting (IVW) was used as the primary method, with MR-Egger, weighted median, and cML-MA serving as supplementary methods for causal inference. Sensitivity analyses such as the MR-Egger intercept test, Cochran's Q test, and leave-one-out analysis were used to assess pleiotropy and heterogeneity. We identified 27 causal relationships between 23 gut microbiota and adrenal function using the IVW method. Among these, Sellimonas enhanced the function of the adrenal cortex reticularis zone (beta = 0.008, 95% CI: 0.002-0.013, P = 0.0057). The cML-MA method supported our estimate (beta = 0.009, 95% CI: 0.004-0.013, P = 2 × 10- 4). Parasutterella, Sutterella, and Anaerofilum affect the functioning of different regions of the adrenal gland. Notably, pleiotropy was not observed. Our findings revealed that the gut microbiota is causally associated with adrenal function. This enhances our understanding of the gut-microbiota-brain axis and provides assistance in the early diagnosis and treatment of adrenal-related diseases in clinical practice.

multimedia: Multimodal Mediation Analysis of Microbiome Data

Mediation analysis has emerged as a versatile tool for answering mechanistic questions in microbiome research because it provides a statistical framework for attributing treatment effects to alternative causal pathways. Using a series of linked regressions, this analysis quantifies how complementary data relate to one another and respond to treatments. Despite these advances, existing software's rigid assumptions often result in users viewing mediation analysis as a black box. We designed the multimedia R package to make advanced mediation analysis techniques accessible, ensuring that statistical components are interpretable and adaptable. The package provides a uniform interface to direct and indirect effect estimation, synthetic null hypothesis testing, bootstrap confidence interval construction, and sensitivity analysis, enabling experimentation with various mediator and outcome models while maintaining a simple overall workflow. The software includes modules for regularized linear, compositional, random forest, hierarchical, and hurdle modeling, making it well-suited to microbiome data. We illustrate the package through two case studies. The first re-analyzes a study of the microbiome and metabolome of Inflammatory Bowel Disease patients, uncovering potential mechanistic interactions between the microbiome and disease-associated metabolites, not found in the original study. The second analyzes new data about the influence of mindfulness practice on the microbiome. The mediation analysis highlights shifts in taxa previously associated with depression that cannot be explained indirectly by diet or sleep behaviors alone. A gallery of examples and further documentation can be found at https://go.wisc.edu/830110.

Effects of Bifidobacterium breve 207-1 on regulating lifestyle behaviors and mental wellness in healthy adults based on the microbiome-gut-brain axis: a randomized, double-blind, placebo-controlled trial

PURPOSE

Our study aimed to explore the efficacy of Bifidobacterium breve 207-1 on specific neurotransmitters and hormones and the ability to regulate lifestyle behaviors in healthy adults.

METHODS

In total, 120 healthy adults with high mental stress, overweight, insomnia, and constipation were randomly assigned to receive low-dose B. breve 207-1 (LD, n = 40), high-dose B. breve 207-1 (HD, n = 40), or placebo (n = 40) for 28 days. Fecal and blood samples were collected and questionnaires were answered before and after the trial. Neurotransmitters and serum hormones were detected using enzyme-linked immunosorbent assay. The gut microbiota composition was assessed using 16 S rRNA sequencing. Short-chain fatty acids (SCFAs) concentrations were determined via gas chromatography-mass spectrometry (GC-MS).

RESULTS

The primary outcome of our study was changes in mental wellness, including neurotransmitters, the hypothalamic-pituitary-adrena (HPA) axis hormones, and the psychological scales. The results showed that γ-aminobutyric acid (GABA) increased significantly and the HPA axis hormones were suppressed overall in the probiotic groups while 5-hydroxytryptamine (5-HT) did not change significantly. However, there was no significant change in mood scale scores. The secondary outcome focused on the ability of 207-1 to regulate the body and lifestyle of healthy adults (e.g., sleep, diet, exercise, etc.). The PSQI scores in the probiotics groups significantly decreased, indicating improved sleep quality. Meanwhile, the probiotic groups had a slight increase in exercise consumption while dietary intake stabilized. By physical examination, the participants showed weight loss although no statistically significant difference was observed between the groups. Then, validated by gut microbiota, changes in the gut microbiota were observed under the effective intervention of 207-1 while short-chain fatty acids (SCFAs) increased in the LD group, particularly acetic and propionic acids. There was a slight decrease in alpha-diversity in the HD group.

CONCLUSION

Bifidobacterium breve 207-1 entered the organism and affected neurotransmitter and the HPA axis hormone levels via the microbiome-gut-brain axis. Meanwhile, 207-1 supplementation improved daily lifestyle behaviors in healthy adults, which may in turn lead to changes in their bodies (e.g. weight and lipid metabolism). However, this study did not find significant mood-modulating efficacy. The mechanism of the overall study is unclear, but we hypothesize that SCFAs may be the key pathway, and more experiments are needed for validation in the future.

TRIAL REGISTRATION

This trial was retrospectively registered in the Chinese Clinical Trial Registry under the accession number ChiCTR2300069453 on March 16, 2023.

Exploratory studies of the antidepressant effect of Cordyceps sinensis polysaccharide and its potential mechanism

Cordyceps sinensis, a traditionally prized medicinal fungus, contains polysaccharides as one of its main bioactive constituents, known for their significant immunomodulatory properties. In this study, we systematically investigated the composition and structure of Cordyceps sinensis polysaccharide, followed by an evaluation of its therapeutic effect on depression using a chronic restraint stress-induced depression model. The polysaccharide CSWP-2, extracted via hot water, precipitated with ethanol, and purified using DEAE-cellulose column chromatography from Cordyceps sinensis, is primarily composed of glucose, mannose, and galactose, with α-1,4-D-glucan as its major structural component. Behavioral tests, immunological profiling, metabolomics, and gut microbiota analyses indicated a notable ameliorative effect of CSWP-2 on depressive-like symptoms in mice. Furthermore, the action of CSWP-2 may be attributed to the modulation of the gut microbiome's abundance and its metabolic impacts, thereby transmitting signals to the host immune system and exerting immunomodulatory activity, ultimately contributing to its antidepressant effects.

Balancing the mind: Toward a complete picture of the interplay between gut microbiota, inflammation and major depressive disorder

The intricate interplay existing between gut microbiota and homeostasis extends to the realm of the brain, where emerging research underscores the significant impact of the microbiota on mood regulation and overall neurological well-being and vice-versa, with inflammation playing a pivotal role in mediating these complex interactions. This comprehensive review explores the complex interplay between inflammation, alterations in gut microbiota, and their impact on major depressive disorder (MDD). It provides a cohesive framework for the puzzle pieces of this triad, emphasizing recent advancements in understanding the gut microbiota and inflammatory states' contribution to the depressive features. Two directions of communication between the gut and the brain in depression are discussed, with inflammation serving as a potential modulator. Therapeutic implications were discussed as well, drawing insights from interventional studies on the effects of probiotics on gut bacterial composition and depressive symptoms. Ultimately, this review will attempt to provide a complete and valuable framework for future research and therapeutic interventions in MDD.

Depressive Symptoms and Gut Microbiota after Bowel Preparation and Colonoscopy: A Pre-Post Intervention Study

Mechanical bowel preparation (MBP) is essential for visualisation of the colon during colonoscopy. Previous studies have identified changes in gut microbiota composition after MBP and colonoscopy. Considering the gut microbiota is increasingly implicated in psychiatry, we explored the potential impact of this intervention on mood and the microbiota-gut-brain axis. We conducted a pre-post intervention study in adults, with timepoints of one week before and one month after MBP and colonoscopy. Our primary outcome was change in average Hospital Anxiety and Depression Scale depression sub-scores. We examined changes in average anxiety, stress, and quality of life scores and gut microbiota composition using 16S rRNA sequencing. We further explored associations between changes in depressive symptoms and gut microbiota and conducted post hoc analyses to explore potential effect modifiers. Average depressive symptom scores decreased one month post-procedure compared to baseline (n = 59; adjusted β = -0.64; 95%CI: -1.18, -0.11). Irritable bowel syndrome (IBS) appeared to moderate this relationship (β = 1.78; 95%CI: 0.292, 3.26); depressive symptoms increased in those with, and decreased in those without, IBS. Reduced alpha diversity, modest effects on beta-diversity, and increases in health-associated genera were observed one month post-procedure. Increases in the CLR-transformed abundances of Ruminococcaceae UCG-009 were associated with improvements in depressive symptoms. There is preliminary evidence of a potential mental health effect of MBP and colonoscopy, particularly for those with IBS, which may be associated with changes to the gut microbiota. Further research is required to confirm these findings and their clinical relevance.