Differences In Gut Microbiome Research Articles

Longitudinal gut microbiome dynamics in relation to age and senescence in a wild animal population.

In humans, gut microbiome (GM) differences are often correlated with, and sometimes causally implicated in, ageing. However, it is unclear how these findings translate in wild animal populations. Studies that investigate how GM dynamics change within individuals, and with declines in physiological condition, are needed to fully understand links between chronological age, senescence and the GM, but have rarely been done. Here, we use longitudinal data collected from a closed population of Seychelles warblers (Acrocephalus sechellensis) to investigate how bacterial GM alpha diversity, composition and stability are associated with host senescence. We hypothesised that GM diversity and composition will differ, and become more variable, in older adults, particularly in the terminal year prior to death, as the GM becomes increasingly dysregulated due to senescence. However, GM alpha diversity and composition remained largely invariable with respect to adult age and did not differ in an individual's terminal year. Furthermore, there was no evidence that the GM became more heterogenous in senescent age groups (individuals older than 6 years), or in the terminal year. Instead, environmental variables such as season, territory quality and time of day, were the strongest predictors of GM variation in adult Seychelles warblers. These results contrast with studies on humans, captive animal populations and some (but not all) studies on non-human primates, suggesting that GM deterioration may not be a universal hallmark of senescence in wild animal species. Further work is needed to disentangle the factors driving variation in GM-senescence relationships across different host taxa.

Sex-specific effects of gut microbiome on shaping bile acid metabolism.

Gut microbiome is a group of microorganisms that plays important roles in contributing to health and diseases. These bacterial compositions have been demonstrated to impact bile acids (BAs) profiles, either by directly metabolizing primary BAs to secondary BAs or indirect ways through host metabolism by influencing BAs synthesis, transportation and conjugation in liver. It has been observed sexually dimorphic gut microbiome and bile acids composition, with variations in expression levels of bile acid metabolizing genes in the liver. However, associations between sex-specific differences in gut microbiome and BAs profiles are not well understood. This study aimed to investigate whether gut microbiome could influence BAs profiles in host in a sexspecific manner. We transplanted cecum feces of male and female C57BL/6 mice to male mice and measured BAs concentrations in feces, serum and liver samples 7 days after fecal transplantation. We found different BAs profiles between mice with male and female gut microbiome, including altering levels and proportions of secondary BAs. We also observed varied expression levels of genes related to bile acid metabolism in the liver and distal ileum. Our results highlight sex-specific effects of gut microbiome on shaping bile acid metabolism through gut bacteria and regulation of host genes.

Associations of plant-based foods, red and processed meat, and dairy with gut microbiome in Finnish adults.

Population-based studies on the associations of plant-based foods, red meat or dairy with gut microbiome are scarce. We examined whether the consumption of plant-based foods (vegetables, potatoes, fruits, cereals), red and processed meat (RPM) or dairy (fermented milk, cheese, other dairy products) are related to gut microbiome in Finnish adults. We utilized data from the National FINRISK/FINDIET 2002 Study (n = 1273, aged 25-64 years, 55% women). Diet was assessed with 48-hour dietary recalls. Gut microbiome was analyzed using shallow shotgun sequencing. We applied multivariate analyses with linear models and permutational ANOVAs adjusted for relevant confounders. Fruit consumption was positively (beta = 0.03, SE = 0.01, P = 0.04), while a dairy subgroup including milk, cream and ice-creams was inversely associated (beta=-0.03, SE 0.01, P = 0.02) with intra-individual gut microbiome diversity (alpha-diversity). Plant-based foods (R2 = 0.001, P = 0.03) and dairy (R2 = 0.002, P = 0.01) but not RPM (R2 = 0.001, P = 0.38) contributed to the compositional differences in gut microbiome (beta-diversity). Plant-based foods were associated with several butyrate producers/cellulolytic species including Roseburia hominis. RPM associations included an inverse association with R. hominis. Dairy was positively associated with several lactic producing/probiotic species including Lactobacillus delbrueckii and potentially opportunistic pathogens including Citrobacter freundii. Dairy, fermented milk, vegetables, and cereals were associated with specific microbial functions. Our results suggest a potential association between plant-based foods and dairy or their subgroups with microbial diversity measures. Furthermore, our findings indicated that all the food groups were associated with distinct overall microbial community compositions. Plant-based food consumption particularly was associated with a larger number of putative beneficial species.

Ambient long-term exposure to organophosphorus pesticides and the human gut microbiome: an observational study

BackgroundOrganophosphorus pesticides (OP) have been associated with various human health conditions. Animal experiments and in-vitro models suggested that OP may also affect the gut microbiota. We examined associations between ambient chronic exposure to OP and gut microbial changes in humans.MethodsWe recruited 190 participants from a community-based epidemiologic study of Parkinson’s disease living in a region known for heavy agricultural pesticide use in California. Of these, 61% of participants had Parkinson’s disease and their mean age was 72 years. Microbiome and predicted metagenome data were generated by 16S rRNA gene sequencing of fecal samples. Ambient long-term OP exposures were assessed using pesticide application records combined with residential addresses in a geographic information system. We examined gut microbiome differences due to OP exposures, specifically differences in microbial diversity based on the Shannon index and Bray–Curtis dissimilarities, and differential taxa abundance and predicted Metacyc pathway expression relying on regression models and adjusting for potential confounders.ResultsOP exposure was not associated with alpha or beta diversity of the gut microbiome. However, the predicted metagenome was sparser and less evenly expressed among those highly exposed to OP (p = 0.04). Additionally, we found that the abundance of two bacterial families, 22 genera, and the predicted expression of 34 Metacyc pathways were associated with long-term OP exposure. These pathways included perturbed processes related to cellular respiration, increased biosynthesis and degradation of compounds related to bacterial wall structure, increased biosynthesis of RNA/DNA precursors, and decreased synthesis of Vitamin B1 and B6.ConclusionIn support of previous animal studies and in-vitro findings, our results suggest that ambient chronic OP pesticide exposure alters gut microbiome composition and its predicted metabolism in humans.

P1222 Gut microbiome differences regarding lifestyle and the history of COVID-19 infection in ulcerative colitis patients

Abstract Background The microbiome contributes to the pathogenesis of ulcerative colitis (UC) but the contribution of different lifestyle and environmental factors to the compositional variability of the gut microbiota is unclear. Also, it is known that microbiota plays an important role in infectious diseases like coronavirus disease 2019 (COVID-19). Methods In 6-month time (June 2021 to December 2021) 49 UC outpatients from Riga East Clinical University Hospital were included in a Cross-sectional study. All patients were divided into groups according to COVID-19 status (COVID-19posvs COVID-19neg) within 6 months. The effect of the lifestyle (smoking cigarettes, alcohol intake, sports activities, and high psychological stress level) and COVID-19 to the gut microbiota in patients with UC was investigated. For taxonomical classifying of the gut microbiome metagenome data, MetaPhlAn v.2.6.0 tool was used. In further analysis gut microbiome (mostly bacteria phyla) and related data was analysed with SPSS 20.0. Results Out of 49 patients, 31(63%) were male and 18(37%) were female, the mean age was Md=38 [IQR:34-51]. Fourteen patients (28.6%) have been COVID-19 pos and 35(71.4%) COVID-19 neg. There were no statistically significant differences between COVID-19 pos and COVID-19 neg patients and their microbiota, nor between COVID-19 pos symptomatic 12(24.5%) and asymptomatic 37(75.5%) patients and their gut microbiome. Out of 49, 24(49%) were doing sports, of those 18(51.4%) were COVD-19neg vs. 6 (42.9%) COVID-19pos, p=0.82. Evaluating differences in the gut microbiome regarding physical activities there was no statistical significance. Of 49 patients, 30(61.2%) have smoked before, while 19(38.8%) haven’t smoked. Medium smoking time was 8 years Md=8 [IQR:4.50-20.0]. Analysing gut microbiome in smokers/non-smokers, and the length of smoking, there were found no statistically significant differences. Thirty-five (71.4%) were using alcohol, and 14(28.6%) were not. Those who were using alcohol had statistically significantly more Firmicutes in their gut microbiome Md= 64.8[IQR:53.7-70.4] than no users Md=48[IQR:37.5-66.3], p=0.041. Regarding high stress levels, those who had less stress 18(36.7%), had more Actinobacteria in their gut microbiome Md=11.7[IQR:6.92-14.8] vs stressful patients 31(63.3%) Md=6.03[IQR:2.23-13.8], p=0.03. Conclusion There were no changes in gut microbiome in COVID-19 positive and COVID-19 negative patients, nor in smokers and no smokers. Alcohol users had more bacteria Firmicutes in their gut microbiome. There were no differences in gut microbiome in UC patients doing or lacking sports. UC patients with less stress had more Actinobacteria in their gut microbiome.

Homogeneity Gut microbiome Characteristics in Autoimmune Epithelitis: Primary Biliary Cholangitis and Primary Sjögren’s Syndrome.

Background : Accumulating studies had revealed that dysbiosis of the gut microbiome was involved in the occurrence and development of Primary biliary cholangitis (PBC) and Primary Sjögren’s syndrome (pSS). Aims : To examine the similarities and differences in gut microbiome as well as the relationship with pathogenesis in PBC and pSS. Methods : High throughput sequencing was conducted to analyze the 16S rDNA V3-V4 region of fecal microbial samples from 109 subjects including PBC (n=38), pSS (n=41) and healthy controls (HC, n=30) from the Affiliated Hospital of Qingdao University. The composition, diversity and markers of gut microbiome were compared between PBC, pSS and HC. Inter-group comparisons were conducted using analysis

DOP30 Cross-ethnic microbiome analyses identify shared and specific signals for Northern Indian IBD patients

Abstract Background Clinical manifestation of the inflammatory bowel disease (IBD) shows considerable variation across the world. We hypothesized these differences may be influenced by geographical differences in gut microbiome. To test this, we investigated the correlation between gut microbiota and the disease phenotypes of IBD in a cohort form the Northern part of India. Methods Stool samples and clinical metadata were collected from 226 IBD patients (198 ulcerative colitis and 28 Crohn’s disease) and 66 controls from a population cohort from the Northern India. We used metagenomic shotgun sequencing to determine diversity, composition and function of the gut microbiota of the participants. Microbiome was then associated to IBD and its subtypes and clinical metadata (e.g. medication use, drug response, and disease activity). We replicated our results in 436 IBD patients and 903 population controls from the Netherlands analyzed using an identical workflow and used machine learning to assess how well do the Indian IBD signals generalize to Dutch IBD. Results We identified reduction in microbiome diversity and changes in beta diversity in Indian IBD patients (FDR < 0.05, replicated in Dutch population) and identified that 319 taxa and 71 biochemical pathways are altered in Indian patients (FDR < 0.05). Of note, 39% of these signals were replicated in the Dutch cohort (at FDR < 0.05 level). We identified strong dysbiosis shared across Indian and Dutch IBD patients, characterized by expansion of opportunistic pathogens (e.g. Genera Clostridium, Streptococcus and Lactobacilli) and oral bacteria (e.g. Streptococcus oralis and Bifidobacterium dentium) as well as reduction in butyrate producers such as Faecalibacterium prausnitzii, Roseburia hominis and Blautia massiliensis. In addition, we found novel pathobionts specific to the Indian cohort (including oral bacteria from Genus Scardovia and Oribacterium; Actinomyces dentalis and Klebsiella pneumoniae). Machine-learning models trained on the Indian cohort were highly predictive in the Indian test set (Sensitivity 0.84, Specificity 0.95) and generalized to Dutch cohort (Sensitivity 0.77, Specificity 0.69). In addition to IBD-associated dysbiosis, we identified links between medication use and gut microbiota independent of the disease activity: use of Tofacitinib (used by 26 UC patients) was linked to decrease in Lactobacilliales and increase in Clostridia, while Prednisolone and Azathioprine associated to reduction in Roseburia and increase in Streptococcus and Granulicatella. Conclusion The IBD patients from Northern India show gut dysbiosis similar to European patients, but also show enrichment in India-specific pathobionts. The microbiome-based diagnostic models generalize across these populations.

Gut Microbial Dysbiosis in Myeloid Neoplasms: Correlations with Clinical and Genomic Features

Background Deeper insights into somatic mutations have advanced our understanding of myeloid malignancies like Myelodysplastic Neoplasms (MDS), Myeloproliferative Neoplasms (MPN), and Acute Myeloid Leukemia (AML), particularly in terms of malignant clone interactions and immune dysregulation. However, the role of diverse extrinsic factors, such as gut microbial dysbiosis, in interacting with and modifying the microenvironment is still being studied. Here we analyzed gut microbial species and function in AML, MDS, and MPN patients, investigating correlation of disease metagenomic signatures with blood indices, somatic mutations, and disease subtype. Methods Fecal samples were collected from 337 Caucasian adult patients with MDS, MPN, and AML at Humanitas Research Hospital, Milan, Italy. Extracted DNA samples were sequenced (Illumina Novaseq 6000) and quality-trimmed data mapped against Integrated Gut Catalog (IGC2) using METEOR pipeline (Plaza Oñate et al., 2019). Human contaminant sequences were removed, and gene count tables were normalized according to the FPKM strategy using MOMR normFreqRPKM function. Results Overall 138 AML patients (63 females, 75 males, average age 62.3 ± 13.64); 93 MPN patients (29 females, 77 males, average age 66.3 ± 10.61) and 106 MDS patients (29 females, 77 males, average age 71.7 ± 10.87) were included. Concerning microbial richness we observed significantly lower richness and diversity in AML patients vs MDS or MPN. Principal Coordinates Analysis (PCoA) at the species level revealed significant differences in gut microbiomes among disease groups (PERMANOVA R2=7.38, p<0.001)(Figure 1A). AML and MDS shared seven depleted species, including three MetaGenomic Species (MGS) for Faecalibacterium prausnitzii, a key beneficial gut bacterium. Random Forest classification modelling to accurately identified AML, MDS, and MPN patients (AUCROC=0.91, 0.89, 0.85,MDS, AML, MPN respectively), with primary distinguishing features tied to increased levels of inflammation-inducing species. We further investigated mutation-specific microbiome signatures using Shannon Diversity:, JAK2 V617F mutated MPN had significantly greater diversity than MDS or AML (log2(MPN/AML)=0.28,p=7.7e-12, log2(MPN/MDS)=0.12,p=1.3e-9)). Additionally, within MDS, patients with SF3B1 mutation were significantly different from those with TP53 mutation (log2(SF3B1/TP53)=0.23,p=0.03)). We conducted a correlation analysis with blood indices. Two depleted signatures in AML and MDS, butyrate producing species such as Faecalibacterium prausnitzii , positively correlated with platelets (rho=0.17,q=0.001) and hemoglobin (rho=0.23, q=1.7e-5). Conversely, enriched species like Erysipiclostridium ramosum showed a negative correlation with hemoglobin (rho=-0.23,q=1.26e-5), and platelet count (rho=-0.17,q=0.002) in AML and MDS. Notably, in MPN, the pattern was reversed; depleted species like Flavonifractor plautii were negatively correlated with hemoglobin (rho=-0.15,p=0.004) and platelet count (rho=-0.19,q=0.4e-3)). (Figure 1B). We compared microbiome signatures at diagnosis and disease relapse in 94 patients with MDS/AML treated with hypomethylating-based therapies. A significant reduced taxonomical abundances was found in samples collected at disease relapse with respect to those from the same subject at diagnosis (p<0.001). Finally, in 133 MDS/AML patients who underwent disease modifying treatment at diagnosis, we evaluate the incidence of severe infections and the possible associations with specific microbiome signatures. We noticed that patients who developed a severe infection (G3-G4) showed a significantly reduced taxonomical abundances in gut microbiome (as evaluated at disease diagnosis before treatment) with respect to those subject who didn't experience relevant infectious complications (P<.001) Conclusion Our study reveals striking correlations between gut microbiome and clinical/genetic features of AML, MDS, and MPN, suggesting gut microbiome as potential disease markers and therapeutic targets. This enhances our grasp of myeloid malignancies' pathophysiology, setting the stage for further investigations into the intricate interaction between the gut microbiome, genetic mutations, and clinical traits in these conditions, potentially leading to the development of microbiome-focused therapies.

Gut feelings: the relations between depression, anxiety, psychotropic drugs and the gut microbiome

ABSTRACT The gut microbiome is involved in the bi-directional relationship of the gut – brain axis. As most studies of this relationship are small and do not account for use of psychotropic drugs (PTDs), we explored the relations of the gut microbiome with several internalizing disorders, while adjusting for PTDs and other relevant medications, in 7,656 Lifelines participants from the Northern Netherlands (5,522 controls and 491 participants with at least one internalizing disorder). Disorders included dysthymia, major depressive disorder (MDD), any depressive disorder (AnyDep: dysthymia or MDD), generalized anxiety disorder (GAD) and any anxiety disorder (AnyAnx: GAD, social phobia and panic disorder). Compared to controls, 17 species were associated with depressive disorders and 3 were associated with anxiety disorders. Around 90% of these associations remained significant (FDR <0.05) after adjustment for PTD use, suggesting that the disorders, not PTD use, drove these associations. Negative associations were observed for the butyrate-producing bacteria Ruminococcus bromii in participants with AnyDep and for Bifidobacterium bifidum in AnyAnx participants, along with many others. Tryptophan and glutamate synthesis modules and the 3,4-Dihydroxyphenylacetic acid synthesis module (related to dopamine metabolism) were negatively associated with MDD and/or dysthymia. After additional adjustment for functional gastrointestinal disorders and irritable bowel syndrome, these relations remained either statistically (FDR <0.05) or nominally (P < 0.05) significant. Overall, multiple bacterial species and functional modules were associated with internalizing disorders, including gut – brain relevant components, while associations to PTD use were moderate. These findings suggest that internalizing disorders rather than PTDs are associated with gut microbiome differences relative to controls.

The role of intestine in metabolic dysregulation in murine Wilson disease.

The clinical manifestations of Wilson disease (WD) are related to copper accumulation in the liver and the brain, but little is known about other tissue involvement regarding metabolic changes in WD. In vitro studies suggested that the loss of intestinal ATP7B affects metabolic dysregulation in WD. We tested this hypothesis by evaluating the gut microbiota and lipidome in 2 mouse models of WD and by characterizing a new mouse model with a targeted deletion of Atp7b in the intestine. Cecal content 16S sequencing and untargeted hepatic and plasma lipidome analyses in the Jackson Laboratory toxic-milk and the Atp7b null global knockout mouse models of WD were profiled and integrated. Intestine-specific Atp7b knockout mice (Atp7bΔIEC) were generated and characterized using targeted lipidome analysis following a high-fat diet challenge. Gut microbiota diversity was reduced in animal models of WD. Comparative prediction analysis revealed amino acid, carbohydrate, and lipid metabolism functions to be dysregulated in the WD gut microbial metagenome. Liver and plasma lipidomic profiles showed dysregulated triglyceride and diglyceride, phospholipid, and sphingolipid metabolism in WD models. However, Atp7bΔIEC mice did not show gut microbiome differences compared to wild type. When challenged with a high-fat diet, Atp7bΔIEC mice exhibited profound alterations to fatty acid desaturation and sphingolipid metabolism pathways as well as altered APOB48 distribution in intestinal epithelial cells. Gut microbiome and lipidome underlie systemic metabolic manifestations in murine WD. Intestine-specific ATP7B deficiency affected both intestinal and systemic response to a high-fat challenge but not the microbiome profile, at least at early stages. WD is a systemic disease in which intestinal-specific ATP7B loss and diet influence the phenotype and the lipidome profile.

Racial and Ethnic Differences in Studies of the Gut Microbiome and Osteoporosis.

The purpose of this review is to summarize the scientific evidence published in the past 5 years examining the epidemiology of bone health as it relates to the gut microbiome, across race and ethnicity groups. The link between the gut microbiome and bone health is well established and is supported by numerous biological mechanisms. However, human study research in this field is dominated by studies of older adults residing in Asian countries. A limited number of epidemiological and randomized controlled trials have been conducted with individuals in other countries; however, they are marked by their racial and ethnic homogeneity, use varied measures of the gut microbiome, and different interventions (where applicable), making comparisons across race and ethnic groups difficult. As the global prevalence of osteoporosis increases, the need for lifestyle interventions is critical. Existing data suggest that racial and ethnic differences in gut microbiome exist. Studies examining the relation between bone health and gut microbial structure and function across diverse racial and ethnic groups are needed to determine appropriate microbiome-based interventions.

Integrated multi-omic analyses provide insight into colon adenoma susceptibility modulation by the gut microbiota.

Colon cancer onset is strongly associated with the differences in microbial taxa in the gastrointestinal tract. Although recent studies highlight the role of individual taxa, the effect of a complex gut microbiome (GM) on the metabolome and host transcriptome is still unknown. We used a multi-omics approach to determine how differences in the GM affect the susceptibility to adenoma development in a rat model of human colon cancer. Ultra-high performance liquid chromatography mass spectrometry of feces collected prior to observable disease onset identified putative metabolite profiles that likely predict future disease severity. Transcriptome analyses performed after disease onset from normal colonic epithelium and tumor tissues show a correlation between GM and host gene expression. Integrated pathway analyses of the metabolome and transcriptome based on putatively identified metabolic features indicate that bile acid biosynthesis is enriched in rats with high tumors along with increased fatty acid metabolism and mucin biosynthesis. Targeted pyrosequencing of the Pirc allele indicates that the GM alters the mechanism of adenoma development and may drive an epigenetic pathway of tumor suppressor silencing. This study reveals how untargeted metabolomics identifies signatures of susceptibility and integrated analyses uncover pathways of differential mechanisms of loss of tumor suppressor gene function and for potential prevention and therapeutic intervention. IMPORTANCE The association between the gut microbiome and colon cancer is significant but difficult to test in model systems. This study highlights the association of differences in the pathogen-free gut microbiome to changes in the host transcriptome and metabolome that correlate with colon adenoma initiation and development in a rat genetic model of early colon cancer. The utilization of a multi-omics approach integrating metabolomics and transcriptomics reveals differences in pathways including bile acid biosynthesis and fatty acid metabolism. The study also shows that differences in gut microbiomes significantly alter the mechanism of adenoma formation, shifting from genetic changes to epigenetic changes that initiate the early loss of tumor suppressor function. These findings enhance our understanding of the gut microbiome's role in colon cancer susceptibility, offer insights into potential biomarkers and therapeutic targets, and may pave the way for future prevention and intervention strategies.

Ischaemic stroke patients present sex differences in gut microbiota.

Gut microbiota plays a role in the pathophysiology of ischaemic stroke (IS) through the bidirectional gut-brain axis. Nevertheless, little is known about sex-specific microbiota signatures in IS occurrence. A total of 89 IS patients and 12 healthy controls were enrolled. We studied the taxonomic differences of the gut microbiota between men and women with IS by shotgun metagenomic sequencing. To evaluate the causal effect of several bacteria on IS risk, we performed a two-sample Mendelian randomisation (MR) with inverse-variance weighting (IVW) using genome-wide association analysis (GWAS) summary statistics from two cohorts of 5959 subjects with genetic and microbiota data and 1,296,908 subjects with genetic and IS data, respectively. α-Diversity analysis measured using Observed Species (p = 0.017), Chao1 (p = 0.009) and Abundance-based Coverage Estimator (p = 0.012) indexes revealed that IS men have a higher species richness compared with IS women. Moreover, we found sex-differences in IS patients in relation to the phylum Fusobacteria, class Fusobacteriia, order Fusobacteriales and family Fusobacteriaceae (all Bonferroni-corrected p < 0.001). MR confirmed that increased Fusobacteriaceae levels in the gut are causally associated with an increased risk of IS (IVW p = 0.02, β = 0.32). Our study is the first to indicate that there are gut microbiome differences between men and women with IS, identifying high levels of Fusobacteriaceae in women as a specific risk factor for IS. Incorporating sex stratification analysis is important in the design, analysis and interpretation of studies on stroke and the gut microbiota.

1679-P: L-arginine Ameliorates Polycystic Ovary Syndrome and Attenuates Intestinal Oxidative Stress by Regulating Gut Microbiota

More than half of Polycystic ovary syndrome (PCOS) women are overweight or obese, and weight gain amplifies and worsens the symptoms of PCOS. Hence, it is essential to further understand and treat PCOS women with obesity. Therefore, this study tried to use a multi-omics approach that integrates the gut microbiome, serum metabolomics, serum transcriptomics, and clinical indicators to distinguish obese PCOS from obese non-PCOS women. The stool and blood samples from 33 obese PCOS patients and 30 obese control women were collected. The sequencing results suggested there were significant differences in gut microbiome and metabolites between obese PCOS women and obese women. Of which, the level of L-arginine (Arg) in obese PCOS patients was significantly lower than that in the control group and associated with gut microbiota alterations. Further correlation analysis between metabolite and clinical phenotype showed that Arg was significantly correlated with the clinical phenotype of obese PCOS patients. In this study, C57BL/6 mice were treated with dehydroepiandrosterone (DHEA) with a high-fat diet (HFD) to induce obese PCOS mice models for 3 weeks. PCOS mice were randomly divided into four groups: Arg group, Arg + antibiotic cocktail (ABX) group, PCOS group, and PCOS + ABX group. After 3 weeks of Arg supplementation, the estrous cycle, ovarian morphology, intestinal oxidative stress and intestinal barrier integrity were improved in Arg group PCOS mice, while testosterone levels and insulin resistance levels were decreased. However, these improvements were not observed in the Arg plus ABX group, suggesting that ABX-mediated depletion of the gut microbiome would eliminate these improvements. Then the 16s rRNA sequencing was performed to determine the gut microbiota of the four groups. The results showed that Arg can ameliorate reproductive characteristics of PCOS and attenuate intestinal oxidative stress by regulating gut microbiota. Disclosure D.Dilimulati: None. M.Cai: None. Y.Zhang: None. S.Qu: None. M.Zhang: None.

A Randomized Controlled Trial of Probiotics Targeting Gut Dysbiosis in Huntington's Disease.

Gastrointestinal symptoms are clinical features of Huntington's disease (HD), which adversely affect people's quality of life. We recently reported the first evidence of gut dysbiosis in HD gene expansion carriers (HDGECs). Here, we report on a randomized controlled clinical trial of a 6-week probiotic intervention in HDGECs. The primary objective was to determine whether probiotics improved gut microbiome composition in terms of richness, evenness, structure, and diversity of functional pathways and enzymes. Exploratory objectives were to determine whether probiotic supplementation improved cognition, mood, and gastrointestinal symptoms. Forty-one HDGECs, including 19 early manifest and 22 premanifest HDGECs were compared with 36 matched-healthy controls (HCs). Participants were randomly assigned probiotics or placebo and provided fecal samples at baseline and 6-week follow-up, which were sequenced using 16S-V3-V4 rRNA to characterize the gut microbiome. Participants completed a battery of cognitive tests and self-report questionnaires measuring mood and gastrointestinal symptoms. HDGECs had altered gut microbiome diversity when compared to HCs, indicating gut dysbiosis. Probiotic intervention did not ameliorate gut dysbiosis or have any effect on cognition, mood, or gastrointestinal symptoms. Gut microbiome differences between HDGECs and HCs were unchanged across time points, suggesting consistency of gut microbiome differences within groups. Despite the lack of probiotic effects in this trial, the potential utility of the gut as a therapeutic target in HD should continue to be explored given the clinical symptomology, gut dysbiosis, and positive results from probiotics and other gut interventions in similar neurodegenerative diseases.

Sex Differences in Gut Microbiota Fatty Acid Metabolism in Human Salt Sensitivity of Blood Pressure

Salt sensitivity is a trait in which high dietary sodium (Na+) intake causes an increase in blood pressure. We previously demonstrated that in the gut, elevated dietary Na+ causes dysbiosis. The mechanistic interplay between excess dietary Na+-induced alteration in the gut microbiome and sex differences is less understood. The goal of this study was to identify novel metabolites in salt sensitivity and sex differences in response to a high dietary Na+ intake. We hypothesized that excess dietary salt-induced dysbiosis is associated with distinct metabolomic changes in men and women. We performed plasma metabolomics analysis and measured blood pressure of human volunteers who completed a validated 3-day food record to estimate dietary Na+ intake. Based on the recommendations by the American Heart Association, we classified daily Na+ intake of &lt;2.3g as normal salt and high salt for subjects consuming ≥ 2.3g Na+. Spearman correlation was used to assess the relationship between Na+ intake and blood pressure. We also performed RNA sequencing on human (N=11) monocytes treated with high salt in vitro. The relationship between dietary Na+ intake and mean arterial pressure was different in women (r=0.3422, p=0.0022, N=81) and men (r=0.4552, p=0.0010, N=49). Network analysis of human plasma untargeted metabolome revealed fatty acids as top subnetworks differentially changed with salt intake. In subjects consuming a high Na+ diet, levels of linoleate (1.211 ± 0.330 vs. 0.869 ± 0.170; p&lt;0.001); palmitate (1.155 ± 0.292 vs. 0.924 ± 0.233; p= 0.003); arachidonic acid (1.119 ± 0.242 vs. 0.965 ± 0.201; p=0.015); and 12-hydroxyeicosatetraenoic acid (1.329 ± 0.925 vs. 0.902 ± 0.520; p=0.0469) were higher in women (28) than men (25). In contrast, we observed no sex differences in these parameters between men and women consuming a normal salt diet. RNA sequencing analysis revealed that exposure of human monocytes to high salt in vitro upregulated transcription of fatty acid receptors and arachidonic acid-related genes. Specifically, ALOX12 (277.8 ± 13.8 vs. 169.5 ± 16.7, p&lt;0.0001) which encodes for arachidonate 12-lipoxygenase, ALOX5AP (6459 ± 1553 vs. 2598 ± 30, p=0.0310) which encodes for 5-lipoxygenase activating protein, and FFR2 (418.1 ± 97.8 vs. 115.9 ± 29.4, p=0.0078) which encodes for free fatty acids receptor 2 were increased in human monocytes, and this was associated with a pro-inflammatory phenotype. These findings suggest that excess dietary Na+ is associated with fatty acid metabolism dysregulation, and that the arachidonic acid pathway may potentially play a role in sex differences of salt-sensitive hypertension. This work was supported by American Heart Association grants POST9034281 (to JAI) and 15SDG24890015 (to JFF) and NIH grants K01HL130497 (to AK) as well as Venture Pilot Funding (to AK) from Vanderbilt Microbiome Initiative and Vanderbilt Institute for Infection, Immunology, and Inflammation (VI4) and a P&amp;F award (to JFF) from Vanderbilt University Medical Center's Digestive Disease Research Center supported by NIH grant P30DK058404. This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Bacterial gut microbiome differences in adults with ADHD and in children with ADHD on psychostimulant medication

Recent evidence suggests that there is a link between neurodevelopmental disorders, such as attention-deficit hyperactivity disorder (ADHD), and the gut microbiome. However, most studies to date have had low sample sizes, have not investigated the impact of psychostimulant medication, and have not adjusted for potential confounders, including body mass index, stool consistency and diet. To this end, we conducted the largest, to our knowledge, fecal shotgun metagenomic sequencing study in ADHD, with 147 well-characterized adult and child patients. For a subset of individuals, plasma levels of inflammatory markers and short-chain fatty acids were also measured. In adult ADHD patients (n = 84), compared to controls (n = 52), we found a significant difference in beta diversity both regarding bacterial strains (taxonomic) and bacterial genes (functional). In children with ADHD (n = 63), we found that those on psychostimulant medication (n = 33 on medication vs. n = 30 not on medication) had (i) significantly different taxonomic beta diversity, (ii) lower functional and taxonomic evenness, (iii) lower abundance of the strain Bacteroides stercoris CL09T03C01 and bacterial genes encoding an enzyme in vitamin B12 synthesis, and (iv) higher plasma levels of vascular inflammatory markers sICAM-1 and sVCAM-1. Our study continues to support a role for the gut microbiome in neurodevelopmental disorders and provides additional insights into the effects of psychostimulant medication. However, additional studies are needed to replicate these findings and examine causal relationships with the disorder.

Comparative Gut Microbiome Differences between High and Low Aortic Arch Calcification Score in Patients with Chronic Diseases.

Gut dysbiosis can induce chronic inflammation and contribute to atherosclerosis and vascular calcification. The aortic arch calcification (AoAC) score is a simple, noninvasive, and semiquantitative assessment tool to evaluate vascular calcification on chest radiographs. Few studies have discussed the relationship between gut microbiota and AoAC. Therefore, this study aimed to compare the microbiota composition between patients with chronic diseases and high or low AoAC scores. A total of 186 patients (118 males and 68 females) with chronic diseases, including diabetes mellitus (80.6%), hypertension (75.3%), and chronic kidney disease (48.9%), were enrolled. Gut microbiota in fecal samples were analyzed by sequencing of the 16S rRNA gene, and differences in microbial function were examined. The patients were divided into three groups according to AoAC score, including 103 patients in the low AoAC group (AoAC ≤ 3), 40 patients in the medium AoAC group (3 < AoAC ≤ 6), and 43 patients in the high AoAC group (AoAC > 6). Compared to the low AoAC group, the high AoAC group had a significantly lower microbial species diversity (Chao1 index and Shannon index) and increased microbial dysbiosis index. Beta diversity showed that the microbial community composition was significantly different among the three groups (p = 0.041, weighted UniFrac PCoA). A distinct microbial community structure was found in the patients with a low AoAC, with an increased abundance at the genus level of Agathobacter, Eubacterium coprostanoligenes group, Ruminococcaceae UCG-002, Barnesiella, Butyricimonas, Oscillibacter, Ruminococcaceae DTU089, and Oxalobacter. In addition, there was an increased relative abundance of class Bacilli in the high AoAC group. Our findings support the association between gut dysbiosis and the severity of AoAC in patients with chronic diseases.

Sex Differences in Fatty Acid Metabolism and Blood Pressure Response to Dietary Salt in Humans.

Salt sensitivity is a trait in which high dietary sodium (Na+) intake causes an increase in blood pressure (BP). We previously demonstrated that in the gut, elevated dietary Na+ causes dysbiosis. The mechanistic interplay between excess dietary Na+-induced alteration in the gut microbiome and sex differences is less understood. The goal of this study was to identify novel metabolites in sex differences and blood pressure in response to a high dietary Na+ intake. We performed stool and plasma metabolomics analysis and measured the BP of human volunteers with salt intake above or below the American Heart Association recommendations. We also performed RNA sequencing on human monocytes treated with high salt in vitro. The relationship between BP and dietary Na+ intake was different in women and men. Network analysis revealed that fatty acids as top subnetworks differentially changed with salt intake. We found that women with high dietary Na+ intake have high levels of arachidonic acid related metabolism, suggesting a role in sex differences of the blood pressure response to Na+. The exposure of monocytes to high salt in vitro upregulates the transcription of fatty acid receptors and arachidonic acid-related genes. These findings provide potentially novel insights into metabolic changes underlying gut dysbiosis and inflammation in salt sensitivity of BP.

Differences in peripheral and central metabolites and gut microbiome of laying hens with different feather-pecking phenotypes.

Feather pecking (FP) is a maladaptive behavior in laying hens that is associated with numerous physiological traits, including those involving the central neurotransmitter system and the immune system, which have been identified in many species as being regulated by the gut microbiota via the "microbiota-gut-brain" (MGB) axis. Yet, it is unknown whether and how gut microbiota influences FP by regulating multiple central neurotransmission systems and immune system. This study was measured the prevalence of severe FP (SFP) in the commercial layer farm. The chicken flock with the highest frequency of SFP were selected for FP phenotype identification. Nontargeted metabolomics was performed to investigated the differences in the peripheral and central metabolites and 16S rDNA sequencing was performed to investigated the differences in gut microbiome of laying hens with different FP phenotypes. Correlation analysis was performed to determine the potential mechanism by which the disturbed gut microbiota may modulate host physiology and behavior. The results showed that pullets (12 weeks of age) showed significantly higher SFP frequencies than chicks (6 weeks of age) and adults (22 weeks of age; p < 0.05). Compared to neutrals (N), peckers (P) exhibited the stress-induced immunosuppression with the increased plasma levels of corticosterone and norepinephrine, and the decreased plasma levels of IgA, IL-1, IL-6 and tumor necrosis factor α (p < 0.05). In the cecum, the relative abundances of Bacteroides and Gemmiger were higher in the P group, while Roseburia, Ruminococcus2, Anaerostipes, Lachnospiracea_incertae_sedis and Methanobrevibacter were more enriched in the N group. Moreover, increased plasma levels of L-tryptophan, beta-tyrosine and L-histidine were found in the P group (p < 0.05). Notably, in the P group, hippocampal levels of L-tryptophan, xanthurenic acid, L-histidine and histamine were improved and showed a positive association with L-glutamic acid levels. Plasma levels of L-tryptophan, beta-tyrosine and L-histidine were both positively correlated with Bacteroides abundance but negatively correlated with Methanobrevibacter abundance. Overall, these findings suggest that the development of FP may be affected by the gut microbiota, which regulates the central glutamatergic nerve system by altering the metabolism of tryptophan, histidine and tyrosine.