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BMC Medicine Nov 2022Several recent observational studies have reported that gut microbiota composition is associated with preeclampsia. However, the causal effect of gut microbiota on... (Meta-Analysis)
Meta-Analysis
BACKGROUND
Several recent observational studies have reported that gut microbiota composition is associated with preeclampsia. However, the causal effect of gut microbiota on preeclampsia-eclampsia is unknown.
METHODS
A two-sample Mendelian randomization study was performed using the summary statistics of gut microbiota from the largest available genome-wide association study meta-analysis (n=13,266) conducted by the MiBioGen consortium. The summary statistics of preeclampsia-eclampsia were obtained from the FinnGen consortium R7 release data (5731 cases and 160,670 controls). Inverse variance weighted, maximum likelihood, MR-Egger, weighted median, weighted model, MR-PRESSO, and cML-MA were used to examine the causal association between gut microbiota and preeclampsia-eclampsia. Reverse Mendelian randomization analysis was performed on the bacteria that were found to be causally associated with preeclampsia-eclampsia in forward Mendelian randomization analysis. Cochran's Q statistics were used to quantify the heterogeneity of instrumental variables.
RESULTS
Inverse variance weighted estimates suggested that Bifidobacterium had a protective effect on preeclampsia-eclampsia (odds ratio = 0.76, 95% confidence interval: 0.64-0.89, P = 8.03 × 10). In addition, Collinsella (odds ratio = 0.77, 95% confidence interval: 0.60-0.98, P = 0.03), Enterorhabdus (odds ratio = 0.76, 95% confidence interval: 0.62-0.93, P = 8.76 × 10), Eubacterium (ventriosum group) (odds ratio = 0.76, 95% confidence interval: 0.63-0.91, P = 2.43 × 10), Lachnospiraceae (NK4A136 group) (odds ratio = 0.77, 95% confidence interval: 0.65-0.92, P = 3.77 × 10), and Tyzzerella 3 (odds ratio = 0.85, 95% confidence interval: 0.74-0.97, P = 0.01) presented a suggestive association with preeclampsia-eclampsia. According to the results of reverse MR analysis, no significant causal effect of preeclampsia-eclampsia was found on gut microbiota. No significant heterogeneity of instrumental variables or horizontal pleiotropy was found.
CONCLUSIONS
This two-sample Mendelian randomization study found that Bifidobacterium was causally associated with preeclampsia-eclampsia. Further randomized controlled trials are needed to clarify the protective effect of probiotics on preeclampsia-eclampsia and their specific protective mechanisms.
Topics: Female; Humans; Mendelian Randomization Analysis; Genome-Wide Association Study; Polymorphism, Single Nucleotide; Eclampsia; Pre-Eclampsia; Gastrointestinal Microbiome
PubMed: 36380372
DOI: 10.1186/s12916-022-02657-x -
Nature Communications Dec 2022Depression is one of the most poorly understood diseases due to its elusive pathogenesis. There is an urgency to identify molecular and biological mechanisms underlying...
Depression is one of the most poorly understood diseases due to its elusive pathogenesis. There is an urgency to identify molecular and biological mechanisms underlying depression and the gut microbiome is a novel area of interest. Here we investigate the relation of fecal microbiome diversity and composition with depressive symptoms in 1,054 participants from the Rotterdam Study cohort and validate these findings in the Amsterdam HELIUS cohort in 1,539 subjects. We identify association of thirteen microbial taxa, including genera Eggerthella, Subdoligranulum, Coprococcus, Sellimonas, Lachnoclostridium, Hungatella, Ruminococcaceae (UCG002, UCG003 and UCG005), LachnospiraceaeUCG001, Eubacterium ventriosum and Ruminococcusgauvreauiigroup, and family Ruminococcaceae with depressive symptoms. These bacteria are known to be involved in the synthesis of glutamate, butyrate, serotonin and gamma amino butyric acid (GABA), which are key neurotransmitters for depression. Our study suggests that the gut microbiome composition may play a key role in depression.
PubMed: 36473852
DOI: 10.1038/s41467-022-34502-3 -
Frontiers in Immunology 2021Several studies have reported alterations in gut microbiota composition of Alzheimer's disease (AD) patients. However, the observed differences are not consistent across...
INTRODUCTION
Several studies have reported alterations in gut microbiota composition of Alzheimer's disease (AD) patients. However, the observed differences are not consistent across studies. We aimed to investigate associations between gut microbiota composition and AD biomarkers using machine learning models in patients with AD dementia, mild cognitive impairment (MCI) and subjective cognitive decline (SCD).
MATERIALS AND METHODS
We included 170 patients from the Amsterdam Dementia Cohort, comprising 33 with AD dementia (66 ± 8 years, 46%F, mini-mental state examination (MMSE) 21[19-24]), 21 with MCI (64 ± 8 years, 43%F, MMSE 27[25-29]) and 116 with SCD (62 ± 8 years, 44%F, MMSE 29[28-30]). Fecal samples were collected and gut microbiome composition was determined using 16S rRNA sequencing. Biomarkers of AD included cerebrospinal fluid (CSF) amyloid-beta 1-42 (amyloid) and phosphorylated tau (p-tau), and MRI visual scores (medial temporal atrophy, global cortical atrophy, white matter hyperintensities). Associations between gut microbiota composition and dichotomized AD biomarkers were assessed with machine learning classification models. The two models with the highest area under the curve (AUC) were selected for logistic regression, to assess associations between the 20 best predicting microbes and the outcome measures from these machine learning models while adjusting for age, sex, BMI, diabetes, medication use, and MMSE.
RESULTS
The machine learning prediction for amyloid and p-tau from microbiota composition performed best with AUCs of 0.64 and 0.63. Highest ranked microbes included several short chain fatty acid (SCFA)-producing species. Higher abundance of and lower abundance of group spp., spp., spp., spp., spp., , and spp., was associated with higher odds of amyloid positivity. We found associations between lower abundance of spp., spp., and and higher odds of positive p-tau status.
CONCLUSIONS
Gut microbiota composition was associated with amyloid and p-tau status. We extend on recent studies that observed associations between SCFA levels and AD CSF biomarkers by showing that lower abundances of SCFA-producing microbes were associated with higher odds of positive amyloid and p-tau status.
Topics: Aged; Alzheimer Disease; Biomarkers; Brain-Gut Axis; Cognitive Dysfunction; Comorbidity; Dementia; Disease Susceptibility; Female; Gastrointestinal Microbiome; Humans; Machine Learning; Male; Middle Aged; Risk Factors
PubMed: 35173707
DOI: 10.3389/fimmu.2021.794519 -
Frontiers in Immunology 2022Intestinal dysbiosis is associated with inflammatory bowel disease (IBD). Ulcerative colitis (UC) and Crohn's disease (CD), two subtypes of IBD, are characterized by...
Two-Sample Mendelian Randomization Analysis Investigates Causal Associations Between Gut Microbial Genera and Inflammatory Bowel Disease, and Specificity Causal Associations in Ulcerative Colitis or Crohn's Disease.
BACKGROUND
Intestinal dysbiosis is associated with inflammatory bowel disease (IBD). Ulcerative colitis (UC) and Crohn's disease (CD), two subtypes of IBD, are characterized by unique microbial signatures, respectively. However, it is unclear whether UC or CD has a specific causal relationship with gut microbiota.
OBJECTIVE
To investigate the potential causal associations between gut microbial genera and IBD, UC, or CD, two-sample Mendelian randomization (MR) analyses were conducted.
MATERIALS AND METHODS
We obtained genome-wide association study (GWAS) summary statistics of gut microbiota and IBD, UC, or CD from published GWASs. Two-sample MR analyses were performed to identify potential causal gut microbial genera for IBD, UC, and CD using the inverse-variance weighted (IVW) method. Sensitivity analyses were also conducted to validate the robustness of the primary results of the MR analyses. Finally, a reverse MR analysis was performed to evaluate the possibility of reverse causation.
RESULTS
Combining the results from the primary and sensitivity analyses, six bacterial genera were associated with the risk of IBD, UC, or CD in the IVW method. Briefly, group was associated with a lower risk of IBD (=0.011) and UC (=1.00×10), whereas 2 was associated with a higher risk of IBD (=0.022) and UC (=0.007). In addition, we found a positive association between with IBD (=0.001) and CD (=0.002), and UCG014 with IBD (=0.005) and CD (=0.007). We also noticed a negative association between (=0.044) and IBD, and between UCG001 (=0.023) and CD. We did not find causal effects of IBD, UC, or CD on these bacterial genera in the reverse MR analysis.
CONCLUSION
This study expanded gut microbial genera that were causally associated with the risk of IBD, and also revealed specificity-gut microbial genera for UC or CD.
Topics: Colitis, Ulcerative; Crohn Disease; Gastrointestinal Microbiome; Genome-Wide Association Study; Humans; Inflammatory Bowel Diseases; Mendelian Randomization Analysis
PubMed: 35860271
DOI: 10.3389/fimmu.2022.921546 -
Frontiers in Endocrinology 2023Recent studies have indicated a potential correlation between intestinal bacteria and primary ovarian insufficiency (POI). However, the causal relationship between the... (Meta-Analysis)
Meta-Analysis
BACKGROUND
Recent studies have indicated a potential correlation between intestinal bacteria and primary ovarian insufficiency (POI). However, the causal relationship between the gut microbiota (GM) and POI remains unclear.
METHODS
A bidirectional two-sample Mendelian randomization (MR) study was conducted to investigate the relationship between the GM and POI. Data on the GM were based on the MiBioGen consortium's summary statistics from the most comprehensive genome-wide association study meta-analysis to date (n=13,266), and POI data were obtained from the R8 release of the FinnGen consortium, containing a total of 424 cases and 181,796 controls. A variety of analytical methods, including inverse variance weighting, maximum likelihood, MR-Egger, weighted median, and constrained maximum likelihood and model averaging and Bayesian information criterion, were utilized to explore the connection between the GM and POI. The Cochran's Q statistics were used to evaluate the heterogeneity of instrumental variables. The MR-Egger and MR-pleiotropy residual sum and outlier (PRESSO) methods were used to identify the horizontal pleiotropy of instrumental variables. The MR Steiger test was used to evaluate the strength of causal relationships. A reverse MR study was performed to investigate the causal relationship between POI and the targeted GMs which were indicated to have a causal relationship with POI in the forward MR evaluation.
RESULTS
The inverse variance weighted analysis indicated that Eubacterium (hallii group) (odds ratio [OR]=0.49, 95% confidence interval [CI]: 0.26-0.9, P=0.022) and Eubacterium (ventriosum group) (OR=0.51, 95% CI: 0.27-0.97, P=0.04) had protective effects on POI, and Intestinibacter (OR=1.82, 95% CI: 1.04-3.2, P=0.037) and Terrisporobacter (OR=2.47, 95% CI: 1.14-5.36, P=0.022) had detrimental effects on POI. Results of the reverse MR analysis indicated that POI had no significant influence on the four GMs. No significant heterogeneity or horizontal pleiotropy was observed in the performance of the instrumental variables.
CONCLUSION
This bidirectional two-sample MR study revealed a causal link between Eubacterium (hallii group), Eubacterium (ventriosum group), Intestinibacter, and Terrisporobacter and POI. Additional clinical trials are needed to gain a clearer understanding of the beneficial or detrimental effects of the GMs on POI and their mechanisms of action.
Topics: Female; Humans; Gastrointestinal Microbiome; Bayes Theorem; Genome-Wide Association Study; Mendelian Randomization Analysis; Primary Ovarian Insufficiency
PubMed: 37424857
DOI: 10.3389/fendo.2023.1183219 -
Frontiers in Microbiology 2023Observational studies have provided evidence of a close association between gut microbiota and the progression of chronic hepatitis B (CHB). However, establishing a...
BACKGROUND
Observational studies have provided evidence of a close association between gut microbiota and the progression of chronic hepatitis B (CHB). However, establishing a causal relationship between gut microbiota and CHB remains a subject of investigation.
METHODS
Genome-wide association study (GWAS) summary data of gut microbiota came from the MiBioGen consortium, while the GWAS summary data of CHB came from the Medical Research Council Integrative Epidemiology Unit (IEU) Open GWAS project. Based on the maximum likelihood (ML), Mendelian randomization (MR)-Egger regression, inverse variance weighted (IVW), MR Pleiotropy RESidual Sum and Outlier (MR-PRESSO), and weighted-mode and weighted-median methods, we conducted a bidirectional, two-sample, MR analysis to explore the causal relationship between the gut microbiota and CHB. Additionally, we evaluated the genetic associations between individual gut microbes and CHB using the Linkage disequilibrium score regression (LDSC) program.
RESULTS
According to the IVW method estimates, genetically predicted class Alphaproteobacteria (odds ratio [OR] = 0.57; 95% confidence interval [CI], 0.34-0.96; false discovery rate [FDR] = 0.046), genus group (OR = 0.60; 95% CI, 0.39-0.91; FDR = 0.026), genus (OR = 0.73; 95% CI, 0.56-0.94; FDR = 0.022) exhibited a protective effect against CHB. On the other hand, family Family XIII (OR = 1.79; 95% CI, 1.03-3.12; FDR = 0.061), genus group (OR = 1.34; 95% CI, 1.04-1.74; FDR = 0.043), genus group (OR = 1.59; 95% CI, 1.01-2.51; FDR = 0.056), genus (OR = 1.35; 95% CI, 1.00-1.82; FDR = 0.049), and genus group (OR = 1.69; 95% CI, 1.10-2.61; FDR = 0.076) were associated with an increased risk of CHB. The results from LDSC also indicated a significant genetic correlation between most of the aforementioned gut microbiota and CHB. Our reverse MR analysis demonstrated no causal relationship between genetically predicted CHB and gut microbiota, and we observed no significant horizontal pleiotropy or heterogeneity of instrumental variables (IVs).
CONCLUSION
In this study, we identified three types of gut microbiota with a protective effect on CHB and five types with an adverse impact on CHB. We postulate that this information will facilitate the clinical prevention and treatment of CHB through fecal microbiota transplantation.
PubMed: 37655340
DOI: 10.3389/fmicb.2023.1243811 -
Nature Communications Apr 2023Appendicular lean mass (ALM) associates with mobility and bone mineral density (BMD). While associations between gut microbiota composition and ALM have been reported,...
Appendicular lean mass (ALM) associates with mobility and bone mineral density (BMD). While associations between gut microbiota composition and ALM have been reported, previous studies rely on relatively small sample sizes. Here, we determine the associations between prevalent gut microbes and ALM in large discovery and replication cohorts with information on relevant confounders within the population-based Norwegian HUNT cohort (n = 5196, including women and men). We show that the presence of three bacterial species - Coprococcus comes, Dorea longicatena, and Eubacterium ventriosum - are reproducibly associated with higher ALM. When combined into an anabolic species count, participants with all three anabolic species have 0.80 kg higher ALM than those without any. In an exploratory analysis, the anabolic species count is positively associated with femoral neck and total hip BMD. We conclude that the anabolic species count may be used as a marker of ALM and BMD. The therapeutic potential of these anabolic species to prevent sarcopenia and osteoporosis needs to be determined.
Topics: Male; Humans; Female; Absorptiometry, Photon; Body Composition; Bone Density; Sarcopenia; Osteoporosis
PubMed: 37080991
DOI: 10.1038/s41467-023-37978-9 -
Cancers Nov 2022Cancer cachexia exerts a negative clinical influence on patients with advanced non-small-cell lung cancer (NSCLC) treated with immune checkpoint inhibitors (ICI). The...
Cancer cachexia exerts a negative clinical influence on patients with advanced non-small-cell lung cancer (NSCLC) treated with immune checkpoint inhibitors (ICI). The prognostic impact of body weight change during ICI treatment remains unknown. The gut microbiota (GM) is a key contributor to the response to ICI therapy in cancer patients. However, the association between cancer cachexia and GM and their association with the response to ICIs remains unexplored. This study examined the association of cancer cachexia with GM composition and assessed the impact of GM on clinical outcomes in patients with NSCLC treated with ICIs. In this observational, prospective study, which included 113 Japanese patients with advanced NSCLC treated with ICIs, the prevalence of cachexia was 50.4% (57/113). The median progression-free survival (PFS) and overall survival (OS) were significantly shorter in the cachexia group than in the non-cachexia group (4.3 vs. 11.6 months (p = 0.003) and 12.0 months vs. not reached (p = 0.02), respectively). A multivariable analysis revealed that baseline cachexia was independently associated with a shorter PFS. Moreover, a gain in body weight from the baseline (reversible cachexia) was associated with a significantly longer PFS and OS compared to irreversible cachexia. Microbiome profiling with 16S rRNA analysis revealed that the cachexia group presented an overrepresentation of the commensal bacteria, Escherichia-Shigella and Hungatella, while the non-cachexia group had a preponderance of Anaerostipes, Blautia, and Eubacterium ventriosum. Anaerostipes and E. ventriosum were associated with longer PFS and OS. Moreover, a cachexia status correlated with the systemic inflammatory marker-derived-neutrophil-to-lymphocytes ratio (dNLR) and Lung Immune Prognostic Index (LIPI) indexes. Our study demonstrates that cachexia and longitudinal bodyweight change have a prognostic impact on patients with advanced NSCLC treated with ICI therapy. Moreover, our study demonstrates that bacteria associated with ICI resistance are also linked to cachexia. Targeted microbiota interventions may represent a new type of treatment to overcome cachexia in patients with NSCLC.
PubMed: 36358821
DOI: 10.3390/cancers14215405 -
Frontiers in Cellular and Infection... 2022Recent studies have provided insights into the important contribution of gut microbiota in the development of Pulmonary Tuberculosis (PTB). As a chronic consumptive...
INTRODUCTION
Recent studies have provided insights into the important contribution of gut microbiota in the development of Pulmonary Tuberculosis (PTB). As a chronic consumptive infectious disease, PTB involves many pathological characteristics. At present, research on intestinal flora and clinical pathological Index of PTB is still rare.
METHODS
We performed a cross-sectional study in 63 healthy controls (HCs) and 69 patients with untreated active PTB to assess the differences in their microbiota in feces via 16S rRNA gene sequencing.
RESULTS
Significant alteration of microbial taxonomic and functional capacity was observed in PTB as compared to the HCs. The results showed that the alpha diversity indexes of the PTB patients were lower than the HCs (P<0.05). Beta diversity showed differences between the two groups (P<0.05). At the genus level, the relative abundance of Bacteroides, Parabacteroides and Veillonella increased, while Faecalibacterium, Bifidobacterium, Agathobacter and CAG-352 decreased significantly in the PTB group, when compared with the HCs. The six combined genera, including Lactobacillus, Faecalibacterium, Roseburia, Dorea, Monnoglobus and [Eubacterium]_ventriosum_group might be a set of diagnostic biomarkers for PTB (AUC=0.90). Besides, the predicted bacterial functional pathway had a significant difference between the two groups (P<0.05), which was mainly related to the nutrient metabolism pathway. Significant alterations in the biochemical index were associated with changes in the relative abundance of specific bacteria, the short chain fatty acid (SCFA)-producing bacteria enriched in HCs had a positively correlated with most of the biochemical indexes.
DISCUSSION
Our study indicated that the gut microbiota in PTB patients was significantly different from HCs as characterized by the composition and metabolic pathway, which related to the change of biochemical indexes in the PTB group. It was hypothesized that the abovementioned changes in the gut microbiota could exert an impact on the clinical characteristics of PTB through the regulation of the nutrient utilization pathway of the host by way of the gut-lung axis.
Topics: Humans; Gastrointestinal Microbiome; RNA, Ribosomal, 16S; Cross-Sectional Studies; Bacteria; Tuberculosis, Pulmonary; Feces
PubMed: 36619765
DOI: 10.3389/fcimb.2022.1090889 -
Heliyon Nov 2023Recent studies have shown altered gut microbiome composition in patients with scoliosis. However, the causal effect of gut microbiota on scoliosis remains unknown.
BACKGROUND
Recent studies have shown altered gut microbiome composition in patients with scoliosis. However, the causal effect of gut microbiota on scoliosis remains unknown.
METHODS
A Mendelian randomization (MR) study was conducted to quantify the impact of 191 gut microbiome taxa's instrumental variables from the MibioGen Genome-wide association study (GWAS) on scoliosis risk using data from the FinnGen GWAS (1168 cases and 16,4682 controls). Inverse variance weighted (IVW) was the main method, and MR results were verified by sensitive analysis.
RESULTS
(eligens group), 9, and 2 were discovered to have a protective effect on the risk of scoliosis. UCG009, , 2, (ventriosum group), (FCS020 group), 6, and RF9 may increase the occurrence of scoliosis. Heterogeneity (P > 0.05) and pleiotropy (P > 0.05) analysis confirmed the robustness of the MR results.
CONCLUSION
Our study identified four protective bacteria taxa on scoliosis and seven microbiota that may increase scoliosis occurrence. Further MR analysis is required to corroborate our findings, using a more sophisticated technique to obtain estimates with less bias and greater precision or GWAS summary data with more gut microbiome and scoliosis patients.
PubMed: 37964843
DOI: 10.1016/j.heliyon.2023.e21654