Project description:<p>The pregnancy vaginal microbiome contributes to risk of preterm birth, the primary cause of death in children under 5 years of age. Here we describe direct on-swab metabolic profiling by Desorption Electrospray Ionization Mass Spectrometry (DESI-MS) for sample preparation-free characterisation of the cervicovaginal metabolome in two independent pregnancy cohorts (VMET, n = 160; 455 swabs; VMET II, n = 205; 573 swabs). By integrating metataxonomics and immune profiling data from matched samples, we show that specific metabolome signatures can be used to robustly predict simultaneously both the composition of the vaginal microbiome and host inflammatory status. In these patients, vaginal microbiota instability and innate immune activation, as predicted using DESI-MS, associated with preterm birth, including in women receiving cervical cerclage for preterm birth prevention. These findings highlight direct on-swab metabolic profiling by DESI-MS as an innovative approach for preterm birth risk stratification through rapid assessment of vaginal microbiota-host dynamics.</p><p><br></p><p><strong>Linked cross omic data sets:</strong></p><p>Meta-taxonomics data associated with this study are available in the European Nucleotide Archive (ENA): accession number <a href='https://www.ebi.ac.uk/ena/browser/view/PRJEB11895' rel='noopener noreferrer' target='_blank'>PRJEB11895</a>, <a href='https://www.ebi.ac.uk/ena/browser/view/PRJEB12577' rel='noopener noreferrer' target='_blank'>PRJEB12577</a> and <a href='https://www.ebi.ac.uk/ena/browser/view/PRJEB41427' rel='noopener noreferrer' target='_blank'>PRJEB41427</a>.</p>
Project description:Spontaneous preterm birth (sPTB) is a leading cause of maternal and neonatal morbidity and mortality, yet its prevention and early risk stratification are limited. Previous investigations have suggested that vaginal microbes and metabolites may be implicated in sPTB. Here we performed untargeted metabolomics on 232 second-trimester vaginal samples, 80 from pregnancies ending preterm. We find multiple associations between vaginal metabolites and subsequent preterm birth, and propose that several of these metabolites, including diethanolamine and ethyl glucoside, are exogenous. We observe associations between the metabolome and microbiome profiles previously obtained using 16S ribosomal RNA amplicon sequencing, including correlations between bacteria considered suboptimal, such as Gardnerella vaginalis, and metabolites enriched in term pregnancies, such as tyramine. We investigate these associations using metabolic models. We use machine learning models to predict sPTB risk from metabolite levels, weeks to months before birth, with good accuracy (area under receiver operating characteristic curve of 0.78). These models, which we validate using two external cohorts, are more accurate than microbiome-based and maternal covariates-based models (area under receiver operating characteristic curve of 0.55-0.59). Our results demonstrate the potential of vaginal metabolites as early biomarkers of sPTB and highlight exogenous exposures as potential risk factors for prematurity.
Project description:<p>Preterm birth is the leading cause of neonatal morbidity and mortality. A failure to predict and understand the causes of preterm birth have limited effective interventions and therapeutics. From a cohort of 2,000 pregnant women, we performed a nested case control study on 107 well-phenotyped cases of spontaneous preterm birth (sPTB) and 432 women delivering at term. Modern and innovative Bayesian modeling of vaginal microbiota identified features of these communities associated with PTB. Seven bacterial taxa were shown to have relative abundances significantly associated with an increased risk of sPTB, with a stronger effect in African American women. However, higher vaginal levels of β-defensins significantly decreased the risk of sPTB associated with the vaginal microbiota in an ethnicity-dependent manner. These findings hold promise for the development of novel diagnostics that could more accurately identify women at risk for sPTB early in pregnancy and offer new therapeutic strategies that would include immune modulators and microbiome-based therapeutics to reduce this significant health burden.</p>
Project description:Chorioamnionitis (CA), resulting from intra-amniotic inflammation, is a frequent cause of preterm birth and exposes the immature intestine to bacterial toxins and/or inflammatory mediators before birth via fetal swallowing. This may affect intestinal immune development, interacting with the effects of enteral feeding and gut microbiota colonization just after birth. Using preterm pigs as model for preterm infants, we hypothesized that prenatal exposure to gram-negative endotoxin influences postnatal bacterial colonization and gut immune development. Pig fetuses were given intra-amniotic lipopolysaccharide (LPS) 3 d before preterm delivery by cesarean section, and were compared with litter-mate controls (CON) at birth and after 5 d of formula feeding and spontaneous bacterial colonization. Amniotic fluid was collected for analysis of leukocyte counts and cytokines, and the distal small intestine was analyzed for endotoxin level, morphology and immune cell counts. Intestinal gene expression and microbiota were analyzed by transcriptomics and metagenomics, respectively. At birth, LPS-exposed pigs showed higher intestinal endotoxin, neutrophil/macrophage density and shorter villi. About 1.0% of intestinal genes were affected at birth and DMBT1, a regulator of mucosal immune defense, was identified as the hub gene in the co-expression network. Genes related to innate immune response (TLR2, LBP, CD14, C3, SFTPD), neutrophil chemotaxis (C5AR1, CSF3R, CCL5) and antigen processing (MHC II, CD4) were also affected and expression levels correlated with intestinal neutrophil/macrophage density and amniotic fluid cytokine levels. On day 5, LPS and CON pigs showed similar necrotizing enterocolitis (NEC) lesions, endotoxin levels, morphology, immune cell counts, gene expressions and microbiota (except for difference in some low-abundant species). Our results show that CA markedly affects intestinal genes at preterm birth, including genes related to immune cell infiltration. However, a few days later, following the physiological adaptations to preterm birth, CA had limited effects on intestinal structure, function, gene expression, bacterial colonization and NEC sensitivity. We conclude that short-term, prenatal intra-amniotic inflammation is unlikely to exert marked effects on intestinal immune development in preterm neonates beyond the immediate neonatal period.
2019-10-25 | GSE139366 | GEO
Project description:Urinary microbiota and preterm birth
Project description:Intestinal microbiota colonization is important for intestinal development and health of preterm infants, especially those with extremely low birth weight. Recent studies indicated for a dynamic crosstalk between that gut microbiota and DNA methylome of host intestinal cells. Thereby, we sought to determine the epigenomic and metagenomic consequences of suppression of microbiota colonization in the intestine of preterm neonates to gain insights into biological pathways that shape the interface between the gut microbiota and the preterm intestinal cells. We examined 14 preterm piglets by comparing the conventional preterm neonates with those ones treated with oral antibiotics for genome wide DNA methylation and 16S rDNA microbiome. Our results demonstrated an extensive genome-wide DNA methylation changes in response to the suppression of intestinal microbe colonization, especially genes involved in neonatal immune response signaling and glycol-metabolism pathways were identified. Our study highlights several key genes that might predispose preterm neonates to NEC risk due to their key roles involved in the immune-metabolic networks. Our study not only provided rich omic-data to interpret molecular program in relation with microbiota-associated methylome-proteome network changes, but also confer clinical usage of key gene markers for potential early diagnostics of NEC of preterm neonates.
Project description:DNA methylation (DNAm) plays a determining role in neural cell fate and provides a molecular link between early life stress and life-course neuropsychiatric disease. Preterm birth is a profound environmental stressor that is closely associated with alterations in connectivity of neural systems and long-term neuropsychiatric impairment. The aims of this study were to examine the relationship between preterm birth and DNAm and to investigate factors that contribute to variance in DNAm. DNA was collected from preterm infants (birth < 32 weeks’ gestation) and healthy controls (birth > 37 weeks), and a genome-wide analysis of DNAm was performed; diffusion MRI (dMRI) data were acquired from the preterm group. The major fasciculi were segmented, and fractional anisotropy, mean diffusivity and tract shape were calculated. Principal components analysis was used to investigate the contribution of MRI features and key clinical variables to variance in DNAm. Differentially methylated regions were found within 25 gene bodies and 61 promoters of protein-coding genes in preterm infants compared with controls; 10 of these are associated with neural development or function. Differences detected in the array were validated with pyrosequencing. Ninety-five percent of the variance in DNAm in preterm infants was explained by 23 principal components (PC); corticospinal tract shape associated with 6th PC, and gender and early nutritional exposure associated with the 7th PC. Preterm birth is associated with alterations in the methylome at sites that influence neural development and function. The differentially methylated regions identified provide several promising candidate genes for understanding the genetic/epigenetic basis of preterm brain injury.