Remodeling of the maternal gut microbiome during pregnancy is shaped by parity.

BACKGROUND: The maternal microbiome has emerged as an important factor in gestational health and outcome and is associated with risk of preterm birth and offspring morbidity. Epidemiological evidence also points to successive pregnancies-referred to as maternal parity-as a risk factor for preterm birth, infant mortality, and impaired neonatal growth. Despite the fact that both the maternal microbiome and parity are linked to maternal-infant health, the impact of parity on the microbiome remains largely unexplored, in part due to the challenges of studying parity in humans. RESULTS: Using synchronized pregnancies and dense longitudinal monitoring of the microbiome in pigs, we describe a microbiome trajectory during pregnancy and determine the extent to which parity modulates this trajectory. We show that the microbiome changes reproducibly during gestation and that this remodeling occurs more rapidly as parity increases. At the time of parturition, parity was linked to the relative abundance of several bacterial species, including Treponema bryantii, Lactobacillus amylovorus, and Lactobacillus reuteri. Strain tracking carried out in 18 maternal-offspring "quadrads"-each consisting of one mother sow and three piglets-linked maternal parity to altered levels of Akkermansia muciniphila, Prevotella stercorea, and Campylobacter coli in the infant gut 10 days after birth. CONCLUSIONS: Collectively, these results identify parity as an important environmental factor that modulates the gut microbiome during pregnancy and highlight the utility of a swine model for investigating the microbiome in maternal-infant health. In addition, our data show that the impact of parity extends beyond the mother and is associated with alterations in the community of bacteria that colonize the offspring gut early in life. The bacterial species we identified as parity-associated in the mother and offspring have been shown to influence host metabolism in other systems, raising the possibility that such changes may influence host nutrient acquisition or utilization. These findings, taken together with our observation that even subtle differences in parity are associated with microbiome changes, underscore the importance of considering parity in the design and analysis of human microbiome studies during pregnancy and in infants. Video abstract.

Repeat Biopsy to Assess Duodenal Healing in Children With Celiac Disease and Eosinophilic Gastrointestinal Disorders.

The aim of the study was to determine the correlation between duodenal mucosal biopsies and tissue transglutaminase immunoglobulin A (tTG-IgA) levels in pediatric patients with biopsy-confirmed celiac disease (CD) and eosinophilic gastrointestinal disorders (EGID) who have had repeat duodenal biopsies after initiating a gluten-free diet. Methods: A retrospective chart review was performed of children with CD and EGID seen at the Children's Hospital of Philadelphia between 2003 and 2018. Data collected included duodenal biopsy pathology, celiac serology including tTG-IgA, and symptom reports. Duodenal healing was defined as normal villous architecture and no intraepithelial lymphocytes. These data were compared with tTG-IgA level. Data were analyzed with Fisher exact test and t test methods. Results: Thirty-nine patients had normal IgA and diagnoses of both CD and EGID. At second biopsy, 44% (17/39) of patients showed no histologic evidence of active CD and 36% (14/39) of patients had negative tTG-IgA values. Sixty percent (9/15) of patients with no evidence of CD on biopsy had abnormal tTG-IgA levels, and 57% (8/14) of patients with normal tTG-IgA levels had evidence of active disease on biopsy. Conclusions: The data show that an abnormal tTG-IgA drawn after initiation of a gluten-free diet is not correlated with duodenal mucosal injury in pediatric patients with CD and EGID. This suggests that serologic surveillance with tTG-IgA is not sufficient to monitor CD intestinal healing in this patient cohort. Persistent elevations of tTG-IgA in CD patients with normal duodenal biopsies should prompt investigation into other potential causes.