Plasma Trimethylamine N-Oxide as a Non-Invasive Biomarker for Adenomyosis: A Cross-Sectional Study

Objective To identify novel and noninvasive biomarkers for the diagnosis of adenomyosis and to provide potential therapeutic targets. Design We conducted a cross-sectional study using data from 110 women of reproductive age who underwent pelvic examinations, including patients with adenomyosis, endometriosis, and healthy controls. Setting Hospital-based, at Shanghai Fourth People’s Hospital between October 2021 and October 2022. Sample Women of reproductive age who underwent pelvic examinations. Methods 110 women of reproductive age were initially included in this study. Blood routine test results and plasma metabolite levels were compared among healthy controls, patients with endometriosis, and patients with adenomyosis. Plasma phenylacetylglutamine (PAGln) and trimethylamine N-oxide (TMAO) levels were detected using a Thermo Scientific TSQ Quantis triple quadrupole mass spectrometer. Main Outcome Measures Plasma levels of trimethylamine N-oxide (TMAO) and phenylacetylglutamine (PAGln) were the main laboratory outcome measures, while age, gravidity, and complete blood count parameters served as the main clinical outcome measures. Results Among the 110 women, 25 healthy controls, 21 with endometriosis, and 28 with adenomyosis were included in this study. We found that plasma TMAO levels, but not PAGln levels, were specifically higher in the adenomyosis group (adenomyosis vs. Healthy Control: p = 0.029; adenomyosis vs. endometriosis: p = 0.038; endometriosis vs. Healthy Control: p = 0.999). After filtering women aged 30–40 years, the TMAO level in the adenomyosis group remained higher than that in the endometriosis group (p = 0.016). Conclusions Increased plasma TMAO levels may be a potential predictor for the diagnosis and treatment of adenomyosis.