Effects of maternal type 1 diabetes and confounding factors on neonatal microbiomes

Abstract

Aims/hypothesis Body niche-specific microbiota in maternal–neonatal dyads from gravidae with type 1 diabetes have not been quantitatively and functionally examined. Similarly, the impact of pregnancy-specific factors, such as the presence of comorbidities known to occur more frequently among gravidae with type 1 diabetes, including Caesarean delivery, as well as antibiotic prophylaxis, level of glycaemic control during each trimester of pregnancy and insulin administration, has not been adequately considered. The aims of this study were to characterise the maternal and neonatal microbiomes, assess aspects of microbiota transfer from the maternal microbiomes to the neonatal microbiome and explore the impact of type 1 diabetes and confounding factors on the microbiomes. Methods In this observational case–control study, we characterised microbiome community composition and function using 16S rRNA amplicon sequencing in a total of 514 vaginal, rectal and ear-skin swabs and stool samples derived from 92 maternal–neonatal dyads (including 50 gravidae with type 1 diabetes) and in-depth clinical metadata from throughout pregnancy and delivery. Results Type 1 diabetes-specific microbiota were identified among gravidae with type 1 diabetes and their neonates. Neonatal microbiome profiles of ear-skin swabs and stool samples were established, indicating the taxa more prevalent among neonates born to mothers with type 1 diabetes compared with neonates born to control mothers. Without taking into account the type 1 diabetes status of mothers, both delivery mode and intrapartum antibiotic prophylaxis were found to have an influence on neonatal microbiota composition (both p=0.001). In the logistic regression analysis involving all confounding variables, neonatal ear-skin microbiome variation was explained by maternal type 1 diabetes status (p=0.020) and small for gestational age birthweight (p=0.050). Moreover, in women with type 1 diabetes, a relationship was found between HbA1c levels >55 mmol/mol (>7.2%) measured in the first trimester of pregnancy and neonatal ear-skin microbiota composition (p=0.008). In the PICRUSt (Phylogenetic Investigation of Communities by Reconstruction of Unobserved States) assessment, pathways concerning carbohydrate biosynthesis were predicted as key elements of the microbial functional profiles dysregulated in type 1 diabetes. Additionally, in SourceTracker analysis, we found that, on average, 81.0% of neonatal microbiota was attributed to maternal sources. An increase in the contribution of maternal rectum microbiota and decrease in the contribution of maternal cervix microbiota were found in ear-skin samples of vaginally delivered neonates of mothers with type 1 diabetes compared with neonates born to control mothers (83.2% vs 59.5% and 0.7% vs 5.2%, respectively). Conclusions/interpretation These findings indicate that, in addition to maternal type 1 diabetes, glycaemic dysregulation before/in the first trimester of pregnancy, mode of delivery and intrapartum antibiotic prophylaxis may contribute to the inoculation and formation of the neonatal microbiomes. Data availability The BioProject (PRJNA961636) and associated SRA metadata are available at http://www.ncbi.nlm.nih.gov/bioproject/961636. Processed data on probiotic supplementation and the PICRUSt analysis are available in the Mendeley Data Repository (https://doi.org/10.17632/g68rwnnrfk.1). Graphical Abstract

The impact of gestational diabetes on functional capacity of the infant gut microbiome is modest and transient

“… 9 In utero exposure to maternal type 1 diabetes (T1D), and in particular poorly regulated T1D, has recently been associated with a distinct infant rectal and skin microbiomes as early as the first day of life. 10 Gestational diabetes mellitus (GDM) is a relatively common metabolic derangement of pregnancy, occurring in 3–20% of pregnancies 11 in which mothers exhibit hyperglycemia during the later stages of gestation. 12 While maternal hyperglycemia is generally manageable with dietary changes, and in fewer cases exogenous insulin or metformin, and often resolves after birth, it can increase the risk of type 2 diabetes and other metabolic disorders in both the mother and offspring in later life.…”

“…The composition of the neonatal ear-skin microbiome was related to maternal levels of HbA1c in first trimester in a beta-diversity analysis. 10 While such dysbioses in infants have been postulated as contributory to the increased risk of cardiometabolic diseases, little is known concerning the functional implications of such microbiome shifts.…”