Association between microbial composition, diversity, and function of the maternal gastrointestinal microbiome with impaired glucose tolerance on the glucose challenge test

Stress and depression-associated shifts in gut microbiota: A pilot study of human pregnancy

Background

Psychosocial stress and mood-related disorders, such as depression, are prevalent and vulnerability to these conditions is heightened during pregnancy. Psychosocial stress induces consequences via several mechanisms including the gut microbiota-brain axis and associated signaling pathways. Previous preclinical work indicates that prenatal stress alters maternal gut microbial composition and impairs offspring development. Importantly, although the fecal and vaginal microenvironments undergo alterations across pregnancy, we lack consensus regarding which shifts are adaptive or maladaptive in the presence of prenatal stress and depression. Clinical studies interrogating these relationships have identified unique taxa but have been limited in study design.

Methods

We conducted a prospective cohort study of pregnant individuals consisting of repeated administration of psychometrics (Perceived Stress Scale (PSS) and Center for Epidemiological Studies Depression Scale (CES-D)) and collection of fecal and vaginal microbiome samples. Fecal and vaginal microbial community composition across psychometric responses were interrogated using full-length 16S rRNA sequencing followed by α and β-diversity metrics and taxonomic abundance.

Results

Early pregnancy stress was associated with increased abundance of fecal taxa not previously identified in related studies, and stress from late pregnancy through postpartum was associated with increased abundance of typical vaginal taxa and opportunistic pathogens in the fecal microenvironment. Additionally, in late pregnancy, maternal stress and depression scores were associated with each other and with elevated maternal C-C motif chemokine ligand 2 (CCL2) concentrations. At delivery, concordant with previous literature, umbilical CCL2 concentration was negatively correlated with relative abundance of maternal fecal Lactobacilli. Lastly, participants with more severe depressive symptoms experienced steeper decreases in prenatal vaginal α-diversity.

Conclusion

These findings a) underscore previous preclinical and clinical research demonstrating the effects of prenatal stress on maternal microbiome composition, b) suggest distinct biological pathways for the consequences of stress versus depression and c) extend the literature by identifying several taxa which may serve critical roles in mediating this relationship. Thus, further interrogation of the role of specific maternal microbial taxa in relation to psychosocial stress and its sequelae is warranted.

A case of bacteremia caused by Dialister micraerophilus with Enterocloster clostridioformis and Eggerthella lenta in a patient with pyometra

BACKGROUND

Infection by Dialister micraerophilus, an obligate anaerobic gram-negative bacillus, has rarely been described, and its clinical characteristics remain unclear.

CASE PRESENTATION

We report a case of bacteremia caused by D. micraerophilus, Enterocloster clostridioformis, and Eggerthella lenta in a 47-year-old woman, associated with pyometra. D. micraerophilus was identified using 16S rRNA gene sequencing and matrix-assisted laser desorption ionization time-of-flight mass spectrometry. D. micraerophilus was detected by polymerase chain reaction using D. micraerophilus-specific primers and E. clostridioformis and E. lenta was isolated from the drainage pus sample obtained from the pyometra uterus. The patient achieved a cure after abscess drainage and 2-week antibiotic treatment.

CONCLUSIONS

To the best of our knowledge, this is the first report of D. micraerophilus bacteremia. D. micraerophilus may be associated with gynecological infections. Clinicians should consider both oral and gynecological sites when searching to identify the focus of D. micraerophilus infection.

Oral probiotics increased the proportion of Treg, Tfr, and Breg cells to inhibit the inflammatory response and impede gestational diabetes mellitus

BACKGROUND

Children of mothers with gestational diabetes mellitus (GDM) are more prone to acquire type 2 diabetes and obesity as adults. Due to this link, early intervention strategies that alter the gut microbiome may benefit the mother and kid long-term. This work uses metagenomic and transcriptome sequencing to investigate how probiotics affect gut microbiota dysbiosis and inflammation in GDM.

METHODS

GDM and control metagenomic sequencing data were obtained from the SRA database. This metagenomic data helped us understand gut microbiota abundance and function. KEGG detected and extracted functional pathway genes. Transcriptome sequencing data evaluated GDM-related gene expression. Finally, GDM animal models were given probiotics orally to evaluate inflammatory response, regulatory immune cell fractions, and leptin protein levels.

RESULTS

GDM patients had more Fusobacteria and Firmicutes, while healthy people had more Bacteroidetes. Gut microbiota composition may affect GDM by altering the L-aspartate and L-asparagine super pathways. Mannan degradation and the super pathway of L-aspartate and L-asparagine synthesis enhanced in GDM mice with leptin protein overexpression. Oral probiotics prevent GDM by lowering leptin. Oral probiotics increased Treg, Tfr, and Breg cells, which decreased TNF-α and IL-6 and increased TGF-β and IL-10, preventing inflammation and preserving mouse pregnancy.

CONCLUSION

Dysbiosis of the gut microbiota may increase leptin expression and cause GDM. Oral probiotics enhance Treg, Tfr, and Breg cells, which limit the inflammatory response and assist mice in sustaining normal pregnancy. Thus, oral probiotics may prevent GDM, enabling targeted gut microbiota modulation and maternal and fetal health.

Composition of the maternal gastrointestinal microbiome as a predictor of neonatal birth weight

BACKGROUND

The biological mechanism by which the maternal gastrointestinal microbiota contributes to fetal growth and neonatal birth weight is currently unknown. The purpose of this study was to explore how the composition of the maternal microbiome in varying pre-gravid body mass index (BMI) groups are associated with neonatal birth weight adjusted for gestational age.

METHODS

Retrospective, cross-sectional metagenomic analysis of bio-banked fecal swab biospecimens (n = 102) self-collected by participants in the late second trimester of pregnancy.

RESULTS

Through high-dimensional regression analysis using principal components (PC) of the microbiome, we found that the best performing multivariate model explained 22.9% of the variation in neonatal weight adjusted for gestational age. Pre-gravid BMI (p = 0.05), PC3 (p = 0.03), and the interaction of the maternal microbiome with maternal blood glucose on the glucose challenge test (p = 0.01) were significant predictors of neonatal birth weight after adjusting for potential confounders including maternal antibiotic use during gestation and total gestational weight gain.

CONCLUSIONS

Our results indicate a significant association between the maternal gastrointestinal microbiome in the late second trimester and neonatal birth weight adjusted for gestational age. Moderated by blood glucose at the time of the universal glucose screening, the gastrointestinal microbiome may have a role in the regulation of fetal growth.

IMPACT

Maternal blood glucose in the late second trimester significantly moderates the relationship between the maternal gastrointestinal microbiome and neonatal size adjusted for gestational age. Our findings provide preliminary evidence for fetal programming of neonatal birth weight through the maternal gastrointestinal microbiome during pregnancy.