Estrogens Shape the Oral Microbial Miches in Womens Aging Metagenome
Estrogen fluctuations significantly impact oral health in aging women, affecting both oral tissues and the resident microbiome. These hormones are found throughout the oral cavity, playing a crucial role in various physiological processes. However, the specific effects of estrogen on the oral microbial niches in aging women remain underexplored. This study investigated the association between salivary estrogens levels (estradiol and estrone) and oral microbial composition in 30 aging women within the framework of ecosystem ecology to understand the dynamic interactions within the oral environment. We assessed clinical oral health, measured salivary estradiol and estrone levels, and analyzed microbial samples from the buccal mucosa, tongue dorsum, supragingival, and subgingival plaque. Using a multilevel ecological approach, we examined the influence of estrogens on bacterial diversity, richness, community structure, and interspecies interactions within and between oral niches. Our results showed that salivary estrone levels negatively correlated with age, suggesting a link between declining estrone and oral health deterioration. Estrone exhibited niche-specific effects on microbial diversity, positively associating with diversity on the tongue dorsum. Both estradiol and estrone modulated microbial interactions, promoting beneficial bacteria in some niches while suppressing potential pathogens in others. Estradiol promoted Streptococcus in tooth-associated niches and Lactobacillus in the buccal mucosa, while suppressing Gemella, Fusobacterium, and Capnocytophaga. Estrone increased the abundance of several taxa on the tongue and selectively influenced Saccharibacteria species in the buccal mucosa. Network analysis highlighted significant intra-niche microbial interactions, with estrogens acting as key modulators within the oral ecosystem. These results demonstrate the significant role of estrogens in distinctly modulating microbial diversity and interactions across various oral niches. This ecological perspective underscores the need to consider hormonal status in the assessment and treatment of oral health in aging women.