Abstract
BACKGROUND AND AIM: Recent epidemiological research focused on the effects of environmental chemicals on the female reproductive system shows mixed results, which may be partially due to differences in exposure assessment, residual confounding from diet or lifestyle factors, or co-exposures to other chemicals. These challenges highlight the need for more precise exposure assessment at the end-organ of interest to accurately understand the adverse reproductive effects of environmental exposures. Our aim was to perform untargeted metabolomic analysis of menstrual blood, a novel biospecimen, to identify environmental toxins present in the endometrium. METHODS: Whole menstrual effluent samples were collected from four women using a menstrual cup. To evaluate the effect of sample processing times, one portion of menstrual effluent was immediately frozen at -20°C for 24hrs and the second portion was kept at 4°C for 24hrs; both samples were then stored at -80°C. Samples were analyzed using untargeted liquid chromatography with high-resolution mass spectrometry (LC-HRMS). To survey the presence of environmental exposures, LC-HRMS chemical profiles were matched to the ToxCast chemical database, which includes 4,557 commonly used commercial chemicals. Select compounds were confirmed using MS/MS and comparison to reference standards. Principal component analysis (PCA) was used to identify differences within and between individuals’ menstrual blood metabolomic profiles, and the influence of the sample processing method. RESULTS:We identified 261 high confidence matches to environmental chemicals, including suspected reproductive toxicants such as phenols, parabens, phthalates, and organochlorides. PCA showed analysis of menstrual blood samples was highly reproducible, with much higher variability between participants than between an individual’s analytical replicates. CONCLUSIONS:Our results show chemical exposures linked to reproductive toxicity and endocrine disruption are present in the endometrium. In addition, our results demonstrate that menstrual blood can be successfully collected and provides a suitable biofluid for untargeted profiling to assess environmental exposures associated with potential adverse reproductive outcomes. KEYWORDS: metabolomics, exposome, biomarkers of exposure, endocrine disrupting chemicals, reproductive outcomes
Published Version
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