Uterine Microbiome Decline Linked to Reproductive Aging and IVF Outcomes
The research indicates that as women age, beneficial Lactobacillus bacteria in the uterus decline and are replaced by other bacterial species, altering uterine tissue and reducing the success rates of assisted reproduction treatments.
The Shift in the Uterine Microbiome Over Time
Historically, medical science treated the uterus as a sterile environment. Modern clinical understanding recognizes a distinct uterine microbiome that influences reproductive health. These protective strains help regulate local immune defenses and maintain tissue health in younger, healthy women. As these populations shrink, they are frequently replaced by less favorable bacteria such as Lactobacillus iners and Gardnerella vaginalis, creating an environment associated with lower receptivity and reduced success rates in assisted reproduction treatments.
Postbiotics as a Potential Treatment Strategy
To address this tissue degradation without introducing live bacteria, the research team isolated exopolisaccharides (EPS)—complex sugars produced by Lactobacillus gasseri. According to the study findings, L. gasseri demonstrated strong antioxidant and anti-inflammatory properties along with high cellular adhesion. When researchers applied these purified postbiotics to aged mice and cultured human uterine cells, the compound reduced oxidative stress, inflammation, and fibrosis while reversing cellular aging markers. Furthermore, older mice receiving the postbiotic treatment showed notable improvements in embryo implantation rates.
Cellular Mechanisms of Uterine Aging
This overactivation traps a vital protein called YAP outside the cell nucleus, which diminishes the uterus's natural receptivity to an incoming embryo. The L. gasseri postbiotics deactivate the Hippo pathway signal, allowing YAP to return to the nucleus and reactivate the genes necessary to prepare the endometrium for pregnancy. Study authors suggest that applying these specific exopolisaccharides could eventually serve as a complementary strategy to improve endometrial function and reproductive outcomes for women of advanced reproductive age, though clinical trials in humans remain necessary before medical application.
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