Studies on the association between maternal cardiometabolic health and the oral microbiota of mother-child pairs.

A reciprocal interaction has been proposed to exist between cardiometabolic risk factors (CRFs) and the oral microbiota. However, the role of maternal CRFs on the oral microbiota in early life is not well understood. We hypothesized that the cardiometabolic background of the mother might affect the oral microbial composition of the child. Therefore, the main aim of this thesis was to evaluate the role of maternal CRFs on the oral bacteriome and mycobiome of mother-child dyads during pregnancy and early life. In order to achieve our goal, a cohort of women/mother-child pairs was followed from the third trimester of pregnancy, one month after delivery, and 6 months after delivery. In summary, we can conclude that: i) The oral bacteriome but not the mycobiome of women in our study population is associated with CRFs (including arterial hypertension). Some of the implicated genera are involved in the nitrate-nitrite-nitric oxide pathway, supporting the current evidence that oral bacteria may be linked to cardiometabolic health. Women with AH, one of the CRFs, presented higher levels of oral inflammation detected via oral proteome and oral health assessments. These were also linked to oral dysbiosis, highlighting a bidirectional relation between host and microbiota. ii) The oral microbiota (bacteriome and mycobiome) of children was not associated with CRFs up to 6 months after delivery. Specific health, environmental, biological, and behavioral factors were associated with the oral microbiota of children up to 6 months after delivery. These may translate into protective and harmful effects on the microbiota of children, potentially having an impact beyond early life. iii) There was a concordance in potential opportunistic and pathogenic oral bacteria and oral fungi isolates between mother child-pairs, with a similarity in the genotypes of fungi found in mother and children. Furthermore, the oral bacteriome of mothers and children became increasingly more similar over time. In sum, the mother had a significant impact on the oral microbiota composition of the child in early life.