In South Florida, Superfund Sites, including the Homestead Air Force Base (HAFB), have been identified as having elevated levels of phthalates, posing a risk to local communities. Phthalates are endocrine disruptors broadly present in the environment, linked to health issues, including infertility, adverse in vitro fertilization (IVF) outcomes, polycystic ovarian syndrome, and endometriosis.
Global epidemiological studies demonstrated association between phthalate exposure and adverse pregnancy outcomes and fertility problems. Elevated levels of phthalate metabolites were detected not only in urine and follicular fluids, but we also recently found them in endocervical samples of women undergoing IVF. The potential threat posed by phthalates is exacerbated by their capacity to disrupt the gut microbiome. Additionally, variations in vaginal microbiomes were linked to undesirable pregnancy outcomes. This suggests a plausible connection between phthalates, the vaginal microbiome, and infertility. However, molecular mechanisms underpinning this correlation remain unknown. Quorum sensing molecules (QSMs) are a class of chemical signaling molecules used by bacteria in both inter-bacterial and bacteria-to-host communications within microbiomes. Changes in QSMs are correlated with microbial imbalances and associated with activation of inflammatory pathways in humans. Our own research revealed correlation between presence of QSMs in the endocervical mucus of women undergoing IVF and a decreased likelihood of achieving pregnancy. Moreover, our analysis of endocervical samples from non-pregnant women showed increase in pro-inflammatory neutrophils and decrease in anti-inflammatory gamma delta T- cells. Further, pregnant women experiencing a first-trimester loss exhibit a more pronounced proinflammatory state compared to those who continue their pregnancy. Collectively, these findings suggest a connection between vaginal QSMs and vaginal inflammation, possibly playing a role in the reproductive process itself. Significantly, we found phthalate metabolites in the vaginal cavity of women facing fertility issues. This raises concerns about potential for phthalates to trigger inflammatory cycles, leading to reproductive tract inflammation, microbiome changes, increased pro-inflammatory QSMs, and ultimately, detrimental conditions for pregnancy.
As of now, there are no reports investigating altered QSMs and their potential connection to reproductive tract inflammation in women exposed to high levels of phthalates. Given that (1) It is widely acknowledged that phthalates induce inflammation, (2) we have found phthalate metabolites within the vaginal cavities of infertile women, and (3) our research demonstrates that inflammation leads to microbiome dysbiosis, changes in QSM levels, and disparities in immunological markers between pregnant and non-pregnant women, we put forth the hypothesis that exposure to phthalates triggers an inflammatory response, resulting in alterations in microbiome QSMs, ultimately leading to decreased pregnancy rates. Additionally, we propose that QSMs can potentially serve as a biomarker of fertility, particularly for women exposed to high environmental phthalate levels, such as those residing near Superfund sites. To assess our hypothesis, we have formulated three Specific Aims.
Specific Aim 1: Assessment of phthalate exposure, endocervical microbiome and inflammatory markers in samples from women with fertility issues and healthy fertile women
We will determine levels of phthalates/metabolites, QSMs, microbiome composition, and inflammatory cytokines in urine and endocervical swabs. Clinical fertility assessment of patients will be recorded. This will establish a baseline of exposure in the Miami-Dade County’s female population, especially those living near the Superfund HAFB.
Specific Aim 2: Mechanistic investigation of impact of phthalates and QSMs on endocervical cells
We will investigate the mechanism that links phthalate exposure, QSM alterations, and reproductive track changes that lead to effects in fertility via in vitro cell studies. Endocervical cells from women with fertility issues and healthy controls will be challenged with phthalates and/or QSMs to determine immunological response.
Specific Aim 3: Meta-analysis of phthalate, endocervical microbiome, QSM profiles, and clinical factors in endocervical samples from women with fertility problems
We will correlate phthalates, phthalate metabolites, QSMs, endocervical microbiome composition, inflammatory markers, and fertility outcomes via bioinformatics and correlation analysis. Findings will be the first to show phthalate exposure effects on QSMs in endocervical microenvironment and help evaluate QSMs as biomarkers for fertility status screening.
Integration within UM SRP
(1) Share data with Project 2 on pregnancy outcomes. (2) Use Project 3 biosensors for phthalate detection. (4) Inform Project 4 of phthalates/phthalate metabolites found to target precision bioremediation. (5) Work with RSC for clinical sample analysis. (6) Transfer data to DMAC for management and meta-analysis. (7) ART will translate our findings to the public. (8) Through the CEC we will inform the community of our findings and create awareness; (7) Train students in biomedical research, integrating with RETCC through lectures and informing students participating in CEC outreach events of our findings.