A high fiber diet or supplementation with Lactococcus lactis subspecies cremoris to pregnant mice confers protection against intestinal injury in adult offspring.

The diet during pregnancy, or antenatal diet, influences the offspring's intestinal health. We previously showed that antenatal butyrate supplementation reduces injury in adult murine offspring with dextran sulfate sodium (DSS)-induced colitis. Potential modulators of butyrate levels in the intestine include a high fiber diet or dietary supplementation with probiotics. To test this, we supplemented the diet of pregnant mice with high fiber, or with the probiotic bacteria Lactococcus lactis subspecies cremoris or Lactobacillus rhamnosus GG. We then induced chronic colitis with DSS in their adult offspring. We demonstrate that a high fiber antenatal diet, or supplementation with Lactococcus lactis subspecies cremoris during pregnancy diminished the injury from DSS-induced colitis in offspring. These data are evidence that antenatal dietary interventions impact offspring gut health and define the antenatal diet as a therapeutic modality to enhance offspring intestinal health.

Gender-affirming hormone therapy preserves skeletal maturation in young mice via the gut microbiome.

Gender-affirming hormone therapy (GAHT) is often prescribed to transgender (TG) adolescents to alleviate gender dysphoria, but the effect of GAHT on the growing skeleton is unclear. We found GAHT to improve trabecular bone structure via increased bone formation in young male mice and not to affect trabecular structure in female mice. GAHT modified gut microbiome composition in both male and female mice. However, fecal microbiota transfers (FMTs) revealed that GAHT-shaped gut microbiome was a communicable regulator of bone structure and turnover in male, but not in female mice. Mediation analysis identified 2 species of Bacteroides as significant contributors to the skeletal effects of GAHT in male mice, with Bacteroides supplementation phenocopying the effects of GAHT on bone. Bacteroides have the capacity to expand Treg populations in the gut. Accordingly, GAHT expanded intestinal Tregs and stimulated their migration to the bone marrow (BM) in male but not in female mice. Attesting to the functional relevance of Tregs, pharmacological blockade of Treg expansion prevented GAHT-induced bone anabolism. In summary, in male mice GAHT stimulated bone formation and improved trabecular structure by promoting Treg expansion via a microbiome-mediated effect, while in female mice, GAHT neither improved nor impaired trabecular structure.

Fecal microbiota transplantation promotes reduction of antimicrobial resistance by strain replacement.

Multidrug-resistant organism (MDRO) colonization is a fundamental challenge in antimicrobial resistance. Limited studies have shown that fecal microbiota transplantation (FMT) can reduce MDRO colonization, but its mechanisms are poorly understood. We conducted a randomized, controlled trial of FMT for MDRO decolonization in renal transplant recipients called PREMIX (NCT02922816). Eleven participants were enrolled and randomized 1:1 to FMT or an observation period followed by delayed FMT if stool cultures were MDRO positive at day 36. Participants who were MDRO positive after one FMT were treated with a second FMT. At last visit, eight of nine patients who completed all treatments were MDRO culture negative. FMT-treated participants had longer time to recurrent MDRO infection versus PREMIX-eligible controls who were not treated with FMT. Key taxa (Akkermansia muciniphila, Alistipes putredinis, Phocaeicola dorei, Phascolarctobacterium faecium, Alistipes species, Mesosutterella massiliensis, Barnesiella intestinihominis, and Faecalibacterium prausnitzii) from the single feces donor used in the study that engrafted in recipients and metabolites such as short-chain fatty acids and bile acids in FMT-responding participants uncovered leads for rational microbiome therapeutic and diagnostic development. Metagenomic analyses revealed a previously unobserved mechanism of MDRO eradication by conspecific strain competition in an FMT-treated subset. Susceptible Enterobacterales strains that replaced baseline extended-spectrum ß-lactamase-producing strains were not detectable in donor microbiota manufactured as FMT doses but in one case were detectable in the recipient before FMT. These data suggest that FMT may provide a path to exploit strain competition to reduce MDRO colonization.

Defining optimal thresholds for digital Brix refractometry to determine IgG concentration in ewe colostrum and lamb serum in Scottish lowland sheep flocks.

This research aimed to define thresholds for ewe colostrum and lamb serum Brix refractometer measurements in lowland Scottish sheep. This would facilitate the use of this convenient, sheep-side test, enabling quick and accurate identification of poor quality colostrum and prevention of failure of transfer of passive immunity (FTPI) in lambs. Secondary aims were to identify risk factors for poor colostrum quality and FTPI in lambs. Serum samples (n = 233) were collected from lambs between 24 and 48hrs after birth, from four lowland Scottish meat sheep farms. Pre-suckle colostrum samples (n = 112) were also collected from ewes on two of these farms. Farmers provided information on litter size, ewe body condition score, ewe breed and dystocia. Duplicate digital Brix refractometer measurements were compared with immunoglobulin G (IgG) radial immunodiffusion (RID) testing for all colostrum and serum samples. Receiver operating characteristic (ROC) curves were used to redefine thresholds for Brix testing in colostrum and serum. Linear regression models were constructed with colostrum and serum IgG concentration as the outcomes of interest. Colostrum and serum IgG concentrations were highly variable. The prevalence of inadequate colostrum quality (using <50 g/L IgG on RID) was 4.5% (95% CI = 1.5 - 10.1) and the prevalence of FTPI (using <15 g/L IgG in serum on RID) was 7.73% (95% CI = 4.64-11.93). A ewe's colostrum IgG concentration was significantly and positively associated with the serum IgG concentration of her lamb(s) (p = 0.02). ROC analysis defined a Brix threshold for adequate colostrum quality of > 22.10% (sensitivity 80% (95%CI=28.4-99.5), specificity 90% (95%CI=82.3-94.8)). ROC analysis defined a Brix threshold for serum of > 8.65% for adequate passive transfer of immunity in Scottish lambs (sensitivity 94% (95%CI=72.7-99.8), specificity 82% (95%CI=76.6-87.2)). To optimise passive transfer of immunity in lambs, we suggest that ewe colostrum Brix measurements be defined as 'poor' (<22%); 'fair' (22-26%) and 'good' (>26%); and lamb serum as 'poor' (<8%); 'fair' (8-9%) and 'good' (>9%). It is recommended that these tests are used as for flock screening, using samples from multiple animals.

Microbial Changes occurring during oronasal fistula wound healing.

The oral microbiome is a complex community that matures with dental development while oral health is also a recognized risk factor for systemic disease. Despite the oral cavity having a substantial microbial burden, healing of superficial oral wounds occurs quickly and with little scarring. By contrast, creation of an oro-nasal fistula (ONF), often occurring after surgery to correct a cleft palate, is a significant wound healing challenge that is further complicated by a connection of the oral and nasal microbiome. In this study, we characterized the changes in the oral microbiome of mice following a freshly inflicted wound in the oral palate that results in an open and unhealed ONF. Creation of an ONF in mice significantly lowered oral microbiome alpha diversity, with concurrent blooms of Enterococcus faecalis, Staphylococcus lentus, and Staphylococcus xylosus in the oral cavity. Treatment of mice with oral antibiotics one week prior to ONF infliction resulted in a reduction in the alpha diversity, prevented E. faecalis and S. lentus, and S. xylosus blooms, but did not impact ONF healing. Strikingly, delivery of the beneficial microbe Lactococcus lactis subsp. cremoris (LLC) to the wound bed of the freshly inflicted ONF via a PEG-MAL hydrogel vehicle resulted in rapid healing of the ONF. Healing of the ONF was associated with the maintenance of relatively high microbiome alpha diversity, and limited the abundance of E. faecalis and S. lentus, and S. xylosus in the oral cavity. These data demonstrate that a freshly inflicted ONF in the murine palate is associated with a dysbiotic oral microbiome state that may prevent ONF healing, and a bloom of opportunistic pathogens. The data also demonstrate that delivery of a specific beneficial microbe, LLC, to the ONF can boost wound healing, can restore and/or preserve oral microbiome diversity, and inhibit blooms of opportunistic pathogens.

Intestinal barrier dysfunction in murine sickle cell disease is associated with small intestine neutrophilic inflammation, oxidative stress, and dysbiosis.

The intestinal microbiome has emerged as a potential contributor to the severity of sickle cell disease (SCD). We sought to determine whether SCD mice exhibit intestinal barrier dysfunction, inflammation, and dysbiosis. Using the Townes humanized sickle cell mouse model, we found a 3-fold increase in intestinal permeability as assessed via FITC-dextran (4 kDa) assay in SS (SCD) mice compared to AA (wild type) mice (n = 4, p < 0.05). This was associated with 25 to 50% decreases in claudin-1, 3, and 15 and zonula occludens-1 gene expression (n = 8-10, p < 0.05) in the small intestine. Increased Ly6G staining demonstrated more neutrophils in the SS small intestine (3-fold, n = 5, p < 0.05) associated with increased expression of TNFα, IL-17A, CXCL1, and CD68 (2.5 to 5-fold, n = 7-10, p < 0.05). In addition, we observed 30 to 55% decreases in superoxide dismutase-1, glutathione peroxidase-1, and catalase antioxidant enzyme expression (n = 7-8, p < 0.05) concomitant to an increase in superoxide (2-fold, n = 4, p < 0.05). Importantly, all significant observations of a leaky gut phenotype and inflammation were limited to the small intestine and not observed in the colon. Finally, characterization of the composition of the microbiome within the small intestine revealed dysbiosis in SS mice compared to their AA littermates with 47 phyla to species-level significant alterations in amplicon sequence variants. We conclude that the intestinal barrier is compromised in SCD, associated with decreased gene expression of tight junction proteins, enhanced inflammation, oxidative stress, and gut microbiome dysbiosis, all specific to the small intestine.

Callus γδ T cells and microbe-induced intestinal Th17 cells improve fracture healing in mice.

IL-17A (IL-17), a driver of the inflammatory phase of fracture repair, is produced locally by several cell lineages including γδ T cells and Th17 cells. However, the origin of these T cells and their relevance for fracture repair are unknown. Here, we show that fractures rapidly expanded callus γδ T cells, which led to increased gut permeability by promoting systemic inflammation. When the microbiota contained the Th17 cell-inducing taxon segmented filamentous bacteria (SFB), activation of γδ T cells was followed by expansion of intestinal Th17 cells, their migration to the callus, and improved fracture repair. Mechanistically, fractures increased the S1P receptor 1-mediated (S1PR1-mediated) egress of Th17 cells from the intestine and enhanced their homing to the callus through a CCL20-mediated mechanism. Fracture repair was impaired by deletion of γδ T cells, depletion of the microbiome by antibiotics (Abx), blockade of Th17 cell egress from the gut, or Ab neutralization of Th17 cell influx into the callus. These findings demonstrate the relevance of the microbiome and T cell trafficking for fracture repair. Modifications of microbiome composition via Th17 cell-inducing bacteriotherapy and avoidance of broad-spectrum Abx may represent novel therapeutic strategies to optimize fracture healing.

The microbiome restrains melanoma bone growth by promoting intestinal NK and Th1 cell homing to bone.

Bone metastases are frequent complications of malignant melanoma leading to reduced quality of life and significant morbidity. Regulation of immune cells by the gut microbiome influences cancer progression, but the role of the microbiome in tumor growth in bone is unknown. Using intracardiac or intratibial injections of B16-F10 melanoma cells into mice, we showed that gut microbiome depletion by broad-spectrum antibiotics accelerated intraosseous tumor growth and osteolysis. Microbiome depletion blunted melanoma-induced expansion of intestinal NK cells and Th1 cells and their migration from the gut to tumor-bearing bones. Demonstrating the functional relevance of immune cell trafficking from the gut to the bone marrow (BM) in bone metastasis, blockade of S1P-mediated intestinal egress of NK and Th1 cells, or inhibition of their CXCR3/CXCL9-mediated influx into the BM, prevented the expansion of BM NK and Th1 cells and accelerated tumor growth and osteolysis. Using a mouse model, this study revealed mechanisms of microbiota-mediated gut-bone crosstalk that are relevant to the immunological restraint of melanoma metastasis and tumor growth in bone. Microbiome modifications induced by antibiotics might have negative clinical consequences in patients with melanoma.

Spatial and temporal analysis of sheep scab notifications in Scotland, 2014-2019.

BACKGROUND: Sheep scab is considered an endemic disease of great welfare and economic significance in the UK. METHOD: This paper provides an up-to-date assessment of the impact of Sheep Scab (Scotland) Order 2010 on sheep scab notifications in Scotland between 1 January 2014 and 31 December 2019, using data collected by the APHA. RESULTS: In total, 564 sheep scab notifications were reported from 503 unique holdings, of which 44 holdings (8.7%) reported more than one incident. The number of notifications did not differ between years, with 81, 84, 93, 101, 109 and 97 notifications recorded in 2014, 2015, 2016, 2017, 2018 and 2019, respectively: representing an average annual notification prevalence of 0.63% (1/159 flocks/year). A total of 413/564 records documented how notifications were resolved, with macrocyclic lactone and organophosphate treatments accounting for 79.6% and 20.4% of resolutions, respectively. CONCLUSION: Our results suggest that the Order has facilitated the notification of sheep scab in Scotland (including trends and preferred methods of resolution), allowed industry and government to identify previously unidentified potentially free areas as well as recurrent incidents on sheep farms, and start to understand better the geographical and temporal nature of scab outbreaks. However, concerns remain about a potential lack of engagement, evidenced by the low notification prevalence and stagnant annual notification rates.

Gut microbiota regulate Alzheimer's disease pathologies and cognitive disorders via PUFA-associated neuroinflammation.

OBJECTIVE: This study is to investigate the role of gut dysbiosis in triggering inflammation in the brain and its contribution to Alzheimer's disease (AD) pathogenesis. DESIGN: We analysed the gut microbiota composition of 3×Tg mice in an age-dependent manner. We generated germ-free 3×Tg mice and recolonisation of germ-free 3×Tg mice with fecal samples from both patients with AD and age-matched healthy donors. RESULTS: Microbial 16S rRNA sequencing revealed Bacteroides enrichment. We found a prominent reduction of cerebral amyloid-ß plaques and neurofibrillary tangles pathology in germ-free 3×Tg mice as compared with specific-pathogen-free mice. And hippocampal RNAseq showed that inflammatory pathway and insulin/IGF-1 signalling in 3×Tg mice brain are aberrantly altered in the absence of gut microbiota. Poly-unsaturated fatty acid metabolites identified by metabolomic analysis, and their oxidative enzymes were selectively elevated, corresponding with microglia activation and inflammation. AD patients' gut microbiome exacerbated AD pathologies in 3×Tg mice, associated with C/EBPß/asparagine endopeptidase pathway activation and cognitive dysfunctions compared with healthy donors' microbiota transplants. CONCLUSIONS: These findings support that a complex gut microbiome is required for behavioural defects, microglia activation and AD pathologies, the gut microbiome contributes to pathologies in an AD mouse model and that dysbiosis of the human microbiome might be a risk factor for AD.

Butyrate supplementation to pregnant mice elicits cytoprotection against colonic injury in the offspring.

BACKGROUND: Maternal diet during pregnancy can impact progeny health and disease by influencing the offspring's gut microbiome and immune development. Gut microbial metabolism generates butyrate, a short-chain fatty acid that benefits intestinal health. Here we assess the effects of antenatal butyrate on the offspring's gastrointestinal health. We hypothesized that antenatal butyrate supplementation will induce protection against colitis in the offspring. METHODS: C57BL/6 mice received butyrate during pregnancy and a series of experiments were performed on their offspring. RNA sequencing was performed on colonic tissue of 3-week-old offspring. Six-8-week-old offspring were subjected to dextran sulfate sodium-induced colitis. Fecal microbiome analysis was performed on the 6-8-week-old offspring. RESULTS: Antenatal butyrate supplementation dampened transcript enrichment of inflammation-associated colonic genes and prevented colonic injury in the offspring. Antenatal butyrate increased the offspring's stool microbiome diversity and expanded the prevalence of specific gut microbes. CONCLUSIONS: Antenatal butyrate supplementation resulted in downregulation of genes in the offspring's colon that function in inflammatory signaling. In addition, antenatal butyrate supplementation was associated with protection against colitis and an expanded fecal microbiome taxonomic diversity in the offspring. IMPACT: Dietary butyrate supplementation to pregnant mice led to downregulation of colonic genes involved in inflammatory signaling and cholesterol synthesis, changes in the fecal microbiome composition of the offspring, and protection against experimentally induced colitis in the offspring. These data support the mounting evidence that the maternal diet during pregnancy has enduring effects on the offspring's long-term health and disease risk. Although further investigations are needed to identify the mechanism of butyrate's effects on fetal gut development, the current study substantiates the approach of dietary intervention during pregnancy to optimize the long-term gastrointestinal health of the offspring.

Microbial metabolite delta-valerobetaine is a diet-dependent obesogen.

Obesity and obesity-related metabolic disorders are linked to the intestinal microbiome. However, the causality of changes in the microbiome-host interaction affecting energy metabolism remains controversial. Here, we show the microbiome-derived metabolite δ-valerobetaine (VB) is a diet-dependent obesogen that is increased with phenotypic obesity and is correlated with visceral adipose tissue mass in humans. VB is absent in germ-free mice and their mitochondria but present in ex-germ-free conventionalized mice and their mitochondria. Mechanistic studies in vivo and in vitro show VB is produced by diverse bacterial species and inhibits mitochondrial fatty acid oxidation through decreasing cellular carnitine and mitochondrial long-chain acyl-coenzyme As. VB administration to germ-free and conventional mice increases visceral fat mass and exacerbates hepatic steatosis with a western diet but not control diet. Thus, VB provides a molecular target to understand and potentially manage microbiome-host symbiosis or dysbiosis in diet-dependent obesity.

Lactobacillus rhamnosus GG Orchestrates an Antitumor Immune Response.

BACKGROUND & AIMS: In colorectal cancer, approximately 95% of patients are refractory to immunotherapy because of low antitumor immune responses. Therefore, there is an exigent need to develop treatments that increase antitumor immune responses and decrease tumor burden to enhance immunotherapy. METHODS: The gut microbiome has been described as a master modulator of immune responses. We administered the human commensal, Lactobacillus rhamnosus GG (LGG), to mice and characterized the changes in the gut immune landscape. Because the presence of lactobacilli in the gut microbiome has been linked with decreased tumor burden and antitumor immune responses, we also supplemented a genetic and a chemical model of murine intestinal cancer with LGG. For clinical relevance, we therapeutically administered LGG after tumors had formed. We also tested for the requirement of CD8 T cells in LGG-mediated modulation of gut tumor burden. RESULTS: We detected increased colonic CD8 T-cell responses specifically in LGG-supplemented mice. The CD8 T-cell induction was dependent on dendritic cell activation mediated via Toll-like receptor-2, thereby describing a novel mechanism in which a member of the human microbiome induces an intestinal CD8 T-cell response. We also show that LGG decreased tumor burden in the murine gut cancer models by a CD8 T-cell-dependent manner. CONCLUSIONS: These data support the potential use of LGG to augment antitumor immune responses in colorectal cancer patients and ultimately for increasing the breadth and efficacy of immunotherapy.

Cruciferous vegetables (Brassica oleracea) confer cytoprotective effects in Drosophila intestines.

Varieties and cultivars of the cruciferous vegetable Brassica oleracea are widely presumed to elicit positive influences on mammalian health and disease, particularly related to their indole and sulforaphane content. However, there is a considerable gap in knowledge regarding the mechanisms whereby these plant-derived molecules elicit their beneficial effects on the host. In this study, we examined the chemical variation between B. oleracea varieties and evaluated their capacity to both activate Nrf2 in the Drosophila intestine and elicit cytoprotection. Ten types of edible B. oleracea were purchased and B. macrocarpa was wild collected. Fresh material was dried, extracted by double maceration and green kale was also subjected to anaerobic fermentation before processing. Untargeted metabolomics was used to perform Principal Component Analysis. Targeted mass spectral analysis determined the presence of six indole species and quantified indole. Extracts were tested for their capacity to activate Nrf2 in the Drosophila intestine in third instar Drosophila larvae. Cytoprotective effects were evaluated using a paraquat-induced oxidative stress gut injury model. A "Smurf" assay was used to determine protective capacity against a chemically induced leaky gut. Extracts of Brussels sprouts and broccoli activated Nrf2 and protected against paraquat-induced damage and leaky gut. Lacto-fermented kale showed a cytoprotective effect, increasing survival by 20% over the non-fermented extract, but did not protect against leaky gut. The protective effects observed do not directly correlate with indole content, suggesting involvement of multiple compounds and a synergistic mechanism.

At the heart of microbial conversations: endocannabinoids and the microbiome in cardiometabolic risk.

Cardiometabolic syndrome encompasses intertwined risk factors such as hypertension, dyslipidemia, elevated triglycerides, abdominal obesity, and other maladaptive metabolic and inflammatory aberrations. As the molecular mechanisms linking cardiovascular disease and metabolic disorders are investigated, endocannabinoids have emerged as molecules of interest. The endocannabinoid system (ECS) of biologically active lipids has been implicated in several conditions, including chronic liver disease, osteoporosis, and more recently in cardiovascular diseases. The gut microbiome is a major regulator of inflammatory and metabolic signaling in the host, and if disrupted, has the potential to drive metabolic and cardiovascular diseases. Extensive studies have unraveled the impact of the gut microbiome on host physiology, with recent reports showing that gut microbes exquisitely control the ECS, with significant influences on host metabolic and cardiac health. In this review, we outline how modulation of the gut microbiome affects host metabolism and cardiovascular health via the ECS, and how these findings could be exploited as novel therapeutic targets for various metabolic and cardiac diseases.

The gut microbiota is a transmissible determinant of skeletal maturation.

Genetic factors account for the majority of the variance of human bone mass, but the contribution of non-genetic factors remains largely unknown. By utilizing maternal/offspring transmission, cohabitation, or fecal material transplantation (FMT) studies, we investigated the influence of the gut microbiome on skeletal maturation. We show that the gut microbiome is a communicable regulator of bone structure and turnover in mice. In addition, we found that the acquisition of a specific bacterial strain, segmented filamentous bacteria (SFB), a gut microbe that induces intestinal Th17 cell expansion, was sufficient to negatively impact skeletal maturation. These findings have significant translational implications, as the identification of methods or timing of microbiome transfer may lead to the development of bacteriotherapeutic interventions to optimize skeletal maturation in humans. Moreover, the transfer of SFB-like microbes capable of triggering the expansion of human Th17 cells during therapeutic FMT procedures could lead to significant bone loss in fecal material recipients.

Immune Cell Isolation from Murine Intestine for Antibody Array Analysis.

Gut mucosal immune cells play an essential role in health due to their ability to orchestrate host signaling events in response to exogenous antigens. These antigens may originate from microorganisms including viruses, commensal or pathogenic bacteria, or single-celled eukaryotes, as well as from dietary foodstuff-derived proteins or products. A critical technological capacity to understand host responses to antigens is the ability to efficiently isolate and functionally characterize immune cells from intestinal tissues. Additionally, after characterization, it is of paramount importance to understand the exact functions of these immune cells under different disease states or genetic variables. Here, we outline methods for immune cell isolation from murine small and large intestines with the goal of undertaking a functional analysis of isolated cell types using antibody array platforms.

Gut Microbiota in Intestinal and Liver Disease.

It is known that the gut microbiota, the numerically vast and taxonomically diverse microbial communities that thrive in a symbiotic fashion within our alimentary tract, can affect the normal physiology of the gastrointestinal tract and liver. Further, disturbances of the microbiota community structure from both endogenous and exogenous influences as well as the failure of host responsive mechanisms have been implicated in a variety of disease processes. Mechanistically, alterations in intestinal permeability and dysbiosis of the microbiota can result in inflammation, immune activation, and exposure to xenobiotic influences. Additionally, the gut and liver are continually exposed to small molecule products of the microbiota with proinflammatory, gene regulatory, and oxidative properties. Long-term coevolution has led to tolerance and incorporation of these influences into normal physiology and homeostasis; conversely, changes in this equilibrium from either the host or the microbial side can result in a wide variety of immune, inflammatory, metabolic, and neoplastic intestinal and hepatic disorders.

Bifidobacterium adolescentis supplementation attenuates fracture-induced systemic sequelae.

The gut microbiota is an important contributor to both health and disease. While previous studies have reported on the beneficial influences of the gut microbiota and probiotic supplementation on bone health, their role in recovery from skeletal injury and resultant systemic sequelae remains unexplored. This study aimed to determine the extent to which probiotics could modulate bone repair by dampening fracture-induced systemic inflammation. Our findings demonstrate that femur fracture induced an increase in gut permeability lasting up to 7 days after trauma before returning to basal levels. Strikingly, dietary supplementation with Bifidobacterium adolescentis augmented the tightening of the intestinal barrier, dampened the systemic inflammatory response to fracture, accelerated fracture callus cartilage remodeling, and elicited enhanced protection of the intact skeleton following fracture. Together, these data outline a mechanism whereby dietary supplementation with beneficial bacteria can be therapeutically targeted to prevent the systemic pathologies induced by femur fracture.

A Human Microbiota-Associated Murine Model for Assessing the Impact of the Vaginal Microbiota on Pregnancy Outcomes.

Disease states are often linked to large scale changes in microbial community structure that obscure the contributions of individual microbes to disease. Establishing a mechanistic understanding of how microbial community structure contribute to certain diseases, however, remains elusive thereby limiting our ability to develop successful microbiome-based therapeutics. Human microbiota-associated (HMA) mice have emerged as a powerful approach for directly testing the influence of microbial communities on host health and disease, with the transfer of disease phenotypes from humans to germ-free recipient mice widely reported. We developed a HMA mouse model of the human vaginal microbiota to interrogate the effects of Bacterial Vaginosis (BV) on pregnancy outcomes. We collected vaginal swabs from 19 pregnant African American women with and without BV (diagnosed per Nugent score) to colonize female germ-free mice and measure its impact on birth outcomes. There was considerable variability in the microbes that colonized each mouse, with no association to the BV status of the microbiota donor. Although some of the women in the study had adverse birth outcomes, the vaginal microbiota was not predictive of adverse birth outcomes in mice. However, elevated levels of pro-inflammatory cytokines in the uterus of HMA mice were detected during pregnancy. Together, these data outline the potential uses and limitations of HMA mice to elucidate the influence of the vaginal microbiota on health and disease.