Diverticulosis is not associated with altered gut microbiota nor is it predictive of future diverticulitis: a population-based colonoscopy study.

BACKGROUND: The etiopathogenesis of diverticular disease is unknown. OBJECTIVE: To compare the fecal and mucosa-associated microbiota between participants with and without diverticulosis and participants who later developed diverticulitis versus those that did not from a population-based study. METHODS: The PopCol study, conducted in Stockholm, Sweden, invited a random sample of 3556 adults to participate, of which 745 underwent colonoscopy. Overall, 130 participants (17.5%) had diverticulosis. 16S rRNA gene sequencing was conducted on available sigmoid biopsy samples from 529 and fecal samples from 251 individuals. We identified individuals who subsequently developed acute diverticulitis up to 13 years after sample collection. In a case-control design matching for gender, age (+/-5 years), smoking and antibiotic exposure, we compared taxonomic composition, richness and diversity of the microbiota between participants with or without diverticulosis, and between participants who later developed acute diverticulitis versus those who did not. RESULTS: No differences in microbiota richness or diversity were observed between participants with or without diverticulosis, nor for those who developed diverticulitis compared with those who did not. No bacterial taxa were significantly different between participants with diverticulosis compared with those without diverticulosis. Individuals who later developed acute diverticulitis (2.8%) had a higher abundance of genus Comamonas than those who did not (p = .027). CONCLUSIONS: In a population-based cohort study the only significant difference was that those who later develop diverticulitis had more abundance of genus Comamonas. The significance of Comamonas is unclear, suggesting a limited role for the gut microbiota in the etiopathogenesis of diverticular disease.

Cohort profile: the Swedish Maternal Microbiome project (SweMaMi) - assessing the dynamic associations between the microbiome and maternal and neonatal adverse events.

PURPOSE: The Swedish Maternal Microbiome (SweMaMi) project was initiated to better understand the dynamics of the microbiome in pregnancy, with longitudinal microbiome sampling, shotgun metagenomics, extensive questionnaires and health registry linkage. PARTICIPANTS: Pregnant women were recruited before the 20th gestational week during 2017-2021 in Sweden. In total, 5439 pregnancies (5193 unique women) were included. For 3973 pregnancies (73%), samples were provided at baseline, and for 3141 (58%) at all three timepoints (second and third trimester and postpartum). In total, 38 591 maternal microbiome samples (vaginal, faecal and saliva) and 3109 infant faecal samples were collected. Questionnaires were used to collect information on general, reproductive and mental health, diet and lifestyle, complemented by linkage to the nationwide health registries, also used to follow up the health of the offspring (up to age 10). FINDINGS TO DATE: The cohort is fairly representative for the total Swedish pregnant population (data from 2019), with 41% first-time mothers. Women with university level education, born in Sweden, with normal body mass index, not using tobacco-products and aged 30-34 years were slightly over-represented. FUTURE PLANS: The sample and data collection were finalised in November 2021. The next steps are the characterisation of the microbial DNA and linkage to the health and demographic information from the questionnaires and registries. The role of the microbiome on maternal and neonatal outcomes and early-childhood diseases will be explored (including preterm birth, miscarriage) and the role and interaction of other risk factors and confounders (including endometriosis, polycystic ovarian syndrome, diet, drug use). This is currently among the largest pregnancy cohorts in the world with longitudinal design and detailed and standardised microbiome sampling enabling follow-up of both mothers and children. The findings are expected to contribute greatly to the field of reproductive health focusing on pregnancy and neonatal outcomes.

The healthy female microbiome across body sites: effect of hormonal contraceptives and the menstrual cycle.

STUDY QUESTION: How does hormonal contraceptive use and menstrual cycle phase affect the female microbiome across different body sites? SUMMARY ANSWER: The menstrual cycle phase, but not hormonal contraceptive use, is associated with the vaginal and oral but not the gut microbiome composition in healthy young women. WHAT IS KNOWN ALREADY: Women with low vaginal levels of Lactobacillus crispatus are at increased risk of pre-term birth, fertility treatment failure, sexually transmitted infections and gynaecological cancers. Little is known about the effect of hormonal fluctuations on other body site's microbiomes as well as the interplay between them. STUDY DESIGN, SIZE, DURATION: This study includes a cohort of 160 healthy young Danish women using three different contraceptive regimens: non-hormonal methods (n = 54), combined oral contraceptive (COC, n = 52) or levonorgestrel intrauterine system (LNG-IUS, n = 54). Samples were collected from four body sites during the menstrual cycle (menses, follicular and luteal phases) at Copenhagen University Hospital, Rigshospitalet, Denmark. PARTICIPANTS/MATERIALS, SETTING, METHODS: The oral, vaginal, rectal and faecal microbiomes were characterized by shotgun sequencing. Microbial diversity and community distance measures were compared between study groups, menstrual phase timepoints and body sites. All participants answered an extensive questionnaire on current health, lifestyle and sex life. Confounding factors such as smoking, BMI and diet were analysed by PERMANOVA. Plasma oestradiol and progesterone levels are correlated with microbiome composition. MAIN RESULTS AND THE ROLE OF CHANCE: The use of COC and LNG-IUS was not associated with the microbiome composition or diversity. However, increased diversity in the vaginal microbiome was observed during menses, followed by a subsequent expansion of Lactobacillus spp. during the follicular and luteal phases which correlated with measured serum oestradiol levels (r = 0.11, P < 0.001). During menses, 89 women (58%) had a dysbiotic vaginal microbiome with <60% Lactobacillus spp. This declined to 49 (32%) in the follicular phase (P < 0.001) and 44 (29%) in the luteal phase (P < 0.001). During menses, bacterial richness and diversity in saliva reached its lowest point while no differences were observed in the faecal microbiome. The microbiome in different body sites was on average more similar within the same individual than between individuals, despite phase or hormonal treatment. Only the vagina presented a clear cluster structure with dominance of either L. crispatus, Lactobacillus iners, Gardnerella vaginalis or Prevotella spp. LARGE SCALE DATA: The microbiome samples analysed in this study were submitted to the European Nucleotide Archive under project number PRJEB37731, samples ERS4421369-ERS4422941. LIMITATIONS, REASONS FOR CAUTION: The cohort is homogenous which limits extrapolation of the effects of ethnicity and socio-economic status on the microbiome. We only present three defined timepoints across the menstrual phase and miss potential important day to day fluctuations. WIDER IMPLICATIONS OF THE FINDINGS: The use of hormonal contraception did not significantly associate with the microbiome composition in the vagina, faeces, rectum or saliva in healthy young women. This is a welcome finding considering the widespread and prolonged use of these highly efficient contraceptive methods. The menstrual cycle is, however, a major confounding factor for the vaginal microbiome. As such, the time point in the menstrual cycle should be considered when analysing the microbiome of women of reproductive age, since stratifying by vaginal dysbiosis status during menstruation could be misleading. This is the first study to confirm by direct measurements of oestradiol, a correlation with the presence of L. crispatus, adding evidence of a possible hormonal mechanism for the maintenance of this desirable microbe. STUDY FUNDING/COMPETING INTEREST(S): This work was partly funded by the Ferring Pharmaceuticals through a research collaboration with The Centre for Translational Microbiome Research (CTMR) at the Karolinska Institutet (L.W.H., E.F., G.E. and I.S.-K.). Ferring Pharmaceuticals also funded the infrastructure to obtain the clinical samples at Copenhagen University Hospital ([#MiHSN01], M.C.K., Z.B., and H.S.N.). This work was also supported by funding from Rigshospitalet's Research Funds ([#E-22614-01 and #E-22614-02] to M.C.K.) and Oda and Hans Svenningsen's Foundation ([#F-22614-08] to H.S.N.). M.C.K., L.W.H., E.F., Z.B., G.E., L.E., I.S.-K. and H.S.N., are partially funded by Ferring Pharmaceuticals, which also provided funds for the collection and processing of the samples analysed in this study. H.S.N.'s research is further supported by Freya Biosciences and the BioInnovation Institute. H.S.N. has received honoraria from Ferring Pharmaceuticals, Merck A/S, Astra-Zeneca, Cook Medical and Ibsa Nordic. A.N.A. reports no competing interests.

The microbiome in reproductive health: protocol for a systems biology approach using a prospective, observational study design.

STUDY QUESTION: What is the microbiome profile across different body sites in relation to the normal menstrual cycle (with and without hormonal contraception), recurrent pregnancy loss (RPL) (before and during pregnancy, pregnancy loss or birth) and endometriosis (before, during and after surgery)? How do these profiles interact with genetics, environmental exposures, immunological and endocrine biomarkers? WHAT IS KNOWN ALREADY: The microbiome is a key factor influencing human health and disease in areas as diverse as immune functioning, gastrointestinal disease and mental and metabolic disorders. There is mounting evidence to suggest that the reproductive microbiome may be influential in general and reproductive health, fertility and pregnancy outcomes. STUDY DESIGN SIZE DURATION: This is a prospective, longitudinal, observational study using a systems biology approach in three cohorts totalling 920 participants. Since microbiome profiles by shot-gun sequencing have never been investigated in healthy controls during varying phases of the menstrual cycle, patients with RPL and patients with endometriosis, no formal sample size calculation can be performed. The study period is from 2017 to 2024 and allows for longitudinal profiling of study participants to enable deeper understanding of the role of the microbiome and of host-microbe interactions in reproductive health. PARTICIPANTS/MATERIALS SETTING METHODS: Participants in each cohort are as follows: Part 1 MiMens-150 healthy women with or without hormonal contraception; Part 2 MiRPL-200 couples with RPL, 50 healthy couples with prior uncomplicated pregnancy and 150 newborns; Part 3 MiEndo-120 patients with endometriosis requiring surgery with or without hormonal treatment. Microbiome profiles from saliva, faeces, rectal mucosa, vaginal fluid and endometrium will be studied, as well as the Omics profile, endocrine disrupting chemicals and endocrine and immune factors in blood, hair, saliva and urine. Pregnancy loss products, seminal microbiome, HLA types, endometriotic tissue and genetic risk and comprehensive questionnaire data will also be studied, where appropriate. Correlations with mental and physical health will be evaluated. STUDY FUNDING/COMPETING INTERESTS: This work is supported by funding from Ferring Pharmaceuticals ([#MiHSN01] to H.S.N., M.C.K., M.E.M., L.E.V., L.E., I.S.-K., F.B., L.W.H., E.F. and M.H.), Rigshospitalet's Research Funds ([#E-22614-01 and #E-22614-02] to M.C.K. and [#E-22222-06] to S.B.), Niels and Desiree Yde's Foundation (S.B., endocrine analyses [#2015-2784]), the Musikforlæggerne Agnes and Knut Mørk's Foundation (S.B., endocrine and immune analyses [#35108-001]) and Oda and Hans Svenningsen's Foundation ([#F-22614-08] to H.S.N.). Medical writing assistance with this manuscript was provided by Caroline Loat, PhD, and funded by Ferring Pharmaceuticals. H.S.N. reports personal fees from Ferring Pharmaceuticals, Merck Denmark A/S, Ibsa Nordic, Astra Zeneca and Cook Medical outside the submitted work. K.W. is a full-time employee of Ferring Pharmaceuticals. No other conflicts are reported. TRIAL REGISTRATION NUMBER: N/A. TRIAL REGISTRATION DATE: N/A. DATE OF FIRST PATIENT'S ENROLMENT: N/A.

Dysbiosis of the Human Oral Microbiome During the Menstrual Cycle and Vulnerability to the External Exposures of Smoking and Dietary Sugar.

Physiological hormonal fluctuations exert endogenous pressures on the structure and function of the human microbiome. As such, the menstrual cycle may selectively disrupt the homeostasis of the resident oral microbiome, thus compromising oral health. Hence, the aim of the present study was to structurally and functionally profile the salivary microbiome of 103 women in reproductive age with regular menstrual cycle, while evaluating the modifying influences of hormonal contraceptives, sex hormones, diet, and smoking. Whole saliva was sampled during the menstrual, follicular, and luteal phases (n = 309) of the cycle, and the participants reported questionnaire-based data concerning their life habits and oral or systemic health. No significant differences in alpha-diversity or phase-specific clustering of the overall microbiome were observed. Nevertheless, the salivary abundances of genera Campylobacter, Haemophilus, Prevotella, and Oribacterium varied throughout the cycle, and a higher species-richness was observed during the luteal phase. While the overall community structure maintained relatively intact, its functional properties were drastically affected. In particular, 11 functional modules were differentially abundant throughout the menstrual cycle, including pentose phosphate metabolism, and biosynthesis of cobalamin and neurotransmitter gamma-aminobutyric acid. The menstrual cycle phase, but not oral contraceptive usage, was accountable for greater variations in the metabolic pathways of the salivary microbiome. Further co-risk factor analysis demonstrated that Prevotella and Veillonella were increased in current smokers, whereas high dietary sugar consumption modified the richness and diversity of the microbiome during the cycle. This is the first large study to systematically address dysbiotic variations of the oral microbiome during the course of menstrual cycle, and document the additive effect of smoking and sugar consumption as environmental risk factors. It reveals the structural resilience and functional adaptability of the oral microbiome to the endogenous hormonal pressures of the menstrual cycle, while revealing its vulnerability to the exogenous exposures of diet and smoking.

Assessment of In Vitro and In Silico Protocols for Sequence-Based Characterization of the Human Vaginal Microbiome.

The vaginal microbiome has been connected to a wide range of health outcomes. This has led to a thriving research environment but also to the use of conflicting methodologies to study its microbial composition. Here, we systematically assessed best practices for the sequencing-based characterization of the human vaginal microbiome. As far as 16S rRNA gene sequencing is concerned, the V1-V3 region performed best in silico, but limitations of current sequencing technologies meant that the V3-V4 region performed equally well. Both approaches presented very good agreement with qPCR quantification of key taxa, provided that an appropriate bioinformatic pipeline was used. Shotgun metagenomic sequencing presents an interesting alternative to 16S rRNA gene amplification and sequencing but requires deeper sequencing and more bioinformatic expertise and infrastructure. We assessed different tools for the removal of host reads and the taxonomic annotation of metagenomic reads, including a new, easy-to-build and -use reference database of vaginal taxa. This curated database performed as well as the best-performing previously published strategies. Despite the many advantages of shotgun sequencing, none of the shotgun approaches assessed here agreed with the qPCR data as well as the 16S rRNA gene sequencing.IMPORTANCE The vaginal microbiome has been connected to various aspects of host health, including susceptibility to sexually transmitted infections as well as gynecological cancers and pregnancy outcomes. This has led to a thriving research environment but also to conflicting available methodologies, including many studies that do not report their molecular biological and bioinformatic methods in sufficient detail to be considered reproducible. This can lead to conflicting messages and delay progress from descriptive to intervention studies. By systematically assessing best practices for the characterization of the human vaginal microbiome, this study will enable past studies to be assessed more critically and assist future studies in the selection of appropriate methods for their specific research questions.

Ileocolonic Histopathological and Microbial Alterations in the Irritable Bowel Syndrome: A Nested Community Case-Control Study.

INTRODUCTION: Histopathological alterations in the ileum and colon in irritable bowel syndrome (IBS) are controversial, and normal values are poorly established. We hypothesized that changes in mucosal immune cells characterize IBS and key changes in immune composition are associated with the mucosa-associated microbiota (MaM). METHODS: A nested case-control study (48 IBS and 106 controls included) from 745 colonoscopy participants in a random population sample. Intraepithelial lymphocytes (IELs)/100 enterocytes and eosinophils/5 nonoverlapping high-power fields counted; mast cells identified by immunocytochemistry (CD117)/5 high-power fields. Paneth cells quantified per 5 crypts. 16S rRNA gene amplicon sequencing performed on available sigmoid MaM, n = 55 and fecal microbiota, n = 20. Microbiota profiles compared between samples with high and low IEL counts. RESULTS: IBS had increased IELs in the terminal ileum (relative risk ratio = 1.70, 95% confidence interval 1.08-2.76, P = 0.022 adjusted for age, sex, and smoking). Cecal IELs were increased in IBS-diarrhea (relative risk ratio = 2.03, 95% confidence interval 1.13-3.63, P = 0.017). No difference was observed in alpha diversity of MaM or fecal microbiota based on IEL count. There was no difference in beta diversity of the MaM according to IEL count in the terminal ileal (TI) (P = 0.079). High TI IEL counts associated with a significant expansion of the genus Blautia (P = 0.024) and unclassified Clostridiales (P = 0.036) in colon MaM. DISCUSSION: A modest but significant increase in IELs was observed in IBS vs. controls in a population-based setting. Subtle TI and cecal inflammation may play a pathogenic role in IBS but needs confirmation. Modest but discernible differences in the colonic MaM were seen according to TI IEL count but not IBS status.

No distinct microbiome signature of irritable bowel syndrome found in a Swedish random population.

OBJECTIVE: The ethiopathogenesis of irritable bowel syndrome (IBS) is unknown. While a link to the gut microbiome is postulated, the heterogeneity of the healthy gut makes it difficult to draw definitive conclusions. We aimed to describe the faecal and mucosa-associated microbiome (MAM) and health correlates on a community cohort of healthy and IBS individuals with no colonoscopic findings. DESIGN: The PopCol study recruited a random sample of 3556 adults; 745 underwent colonoscopy. IBS was defined by Rome IV criteria and organic disease excluded. 16S rRNA gene sequencing was conducted on sigmoid biopsy samples from 376 representative individuals (63 IBS cases) and faecal samples from 185 individuals (32 IBS cases). RESULTS: While sigmoid MAM was dominated by Lachnospiraceae, faeces presented a higher relative abundance of Ruminococcaceae. Microbial richness in MAM was linearly correlated to that in faeces from the same individual (R²=0.255, p<3E-11) as was diversity (R²=0.06, p=0.0022). MAM diversity decreased with increasing body mass index (BMI; Pearson's r=-0.1, p=0.08) and poorer self-rated health (r=-0.15, p=0.007), but no other health correlates. Faecal microbiome diversity was correlated to stool consistency (r=-0.16, p=0.043). Several taxonomic groups were correlated to age, BMI, depression and self-reported health, including Coprococcus catus associated with lower levels of depression (r=-0.003, p=0.00017). The degree of heterogeneity observed between IBS patients is higher than that observed between healthy individuals. CONCLUSIONS: No distinct microbial signature was observed in IBS. Individuals presenting with low self-rated health or high BMI have lower gut microbiome richness.

Mucosal-associated invariant T cells and oral microbiome in persistent apical periodontitis.

Opportunistic bacteria in apical periodontitis (AP) may pose a risk for systemic dissemination. Mucosal-associated invariant T (MAIT) cells are innate-like T cells with a broad and potent antimicrobial activity important for gut mucosal integrity. It was recently shown that MAIT cells are present in the oral mucosal tissue, but the involvement of MAIT cells in AP is unknown. Here, comparison of surgically resected AP and gingival tissues demonstrated that AP tissues express significantly higher levels of Vα7.2-Jα33, Vα7.2-Jα20, Vα7.2-Jα12, Cα and tumour necrosis factor (TNF), interferon (IFN)-γ and interleukin (IL)-17A transcripts, resembling a MAIT cell signature. Moreover, in AP tissues the MR1-restricted MAIT cells positive for MR1-5-OP-RU tetramer staining appeared to be of similar levels as in peripheral blood but consisted mainly of CD4+ subset. Unlike gingival tissues, the AP microbiome was quantitatively impacted by factors like fistula and high patient age and had a prominent riboflavin-expressing bacterial feature. When merged in an integrated view, the examined immune and microbiome data in the sparse partial least squares discriminant analysis could identify bacterial relative abundances that negatively correlated with Vα7.2-Jα33, Cα, and IL-17A transcript expressions in AP, implying that MAIT cells could play a role in the local defence at the oral tissue barrier. In conclusion, we describe the presence of MAIT cells at the oral site where translocation of oral microbiota could take place. These findings have implications for understanding the immune sensing of polymicrobial-related oral diseases.

Enrichment of oral microbiota in early cystic precursors to invasive pancreatic cancer.

OBJECTIVES: Intraductal papillary mucinous neoplasms (IPMNs) are pancreatic cysts that can progress to invasive pancreatic cancer. Associations between oncogenesis and oral microbiome alterations have been reported. This study aims to investigate a potential intracystic pancreatic microbiome in a pancreatic cystic neoplasm (PCN) surgery patient cohort. DESIGN: Paired cyst fluid and plasma were collected at pancreatic surgery from patients with suspected PCN (n=105). Quantitative and qualitative assessment of bacterial DNA by qPCR, PacBio sequencing (n=35), and interleukin (IL)-1ß quantification was performed. The data were correlated to diagnosis, lesion severity and clinical and laboratory profile, including proton-pump inhibitor (PPI) usage and history of invasive endoscopy procedures. RESULTS: Intracystic bacterial 16S DNA copy number and IL-1ß protein quantity were significantly higher in IPMN with high-grade dysplasia and IPMN with cancer compared with non-IPMN PCNs. Despite high interpersonal variation of intracystic microbiota composition, bacterial network and linear discriminant analysis effect size analyses demonstrated co-occurrence and enrichment of oral bacterial taxa including Fusobacterium nucleatum and Granulicatella adiacens in cyst fluid from IPMN with high-grade dysplasia. The elevated intracystic bacterial DNA is associated with, but not limited to, prior exposure to invasive endoscopic procedures, and is independent from use of PPI and antibiotics. CONCLUSIONS: Collectively, these findings warrant further investigation into the role of oral bacteria in cystic precursors to pancreatic cancer and have added values on the aetiopathology as well as the management of pancreatic cysts.

Colitis-induced colorectal cancer and intestinal epithelial estrogen receptor beta impact gut microbiota diversity.

Chronic inflammation of the colon (colitis) is a risk factor for colorectal cancer (CRC). Hormone-replacement therapy reduces CRC incidences, and the estrogen receptor beta (ERß/ESR2) has been implicated in this protection. Gut microbiota is altered in both colitis and CRC and may influence the severity of both. Here we test the hypothesis that intestinal ERß impacts the gut microbiota. Mice with and without intestine-specific deletion of ERß (ERßKOVil ) were generated using the Cre-LoxP system. Colitis and CRC were induced with a single intraperitoneal injection of azoxymethane (AOM) followed by administration of three cycles of dextran sulfate sodium (DSS) in drinking water. The microbiota population were characterized by high-throughput 16S rRNA gene sequencing of DNA extracted from fecal samples (N = 39). Differences in the microbiota due to AOM/DSS and absence of ERß were identified through bioinformatic analyses of the 16S-Seq data, and the distribution of bacterial species was corroborated using qPCR. We demonstrate that colitis-induced CRC reduced the gut microbiota diversity and that loss of ERß enhanced this process. Further, the Bacteroidetes genus Prevotellaceae_UCG_001 was overrepresented in AOM/DSS mice compared to untreated controls (3.5-fold, p = 0.004), and this was enhanced in females and in ERßKOVil mice. Overall, AOM/DSS enriched for microbiota impacting immune system diseases and metabolic functions, and lack of ERß in combination with AOM/DSS enriched for microbiota impacting carbohydrate metabolism and cell motility, while reducing those impacting the endocrine system. Our data support that intestinal ERß contributes to a more favorable microbiome that could attenuate CRC development.