BiomarkerChronic inflammationGut MicrobiotaHOMA-IRHyperandrogenism

PCOS without hyperandrogenism is associated with higher plasma Trimethylamine N-oxide levels

  • 2020
  • Huang Jiayu, Liu Lin, Chen Chunyan, et al.
Why this matters for your gut health

Most PCOS research focuses on the hyperandrogenic phenotype, leaving the non-hyperandrogenic (non-HA) phenotype — which is especially common among Chinese women with anovulatory infertility — poorly understood. This study explores whether a gut-microbiome-derived metabolite, TMAO, could serve as a novel biomarker linking gut dysbiosis, low-grade inflammation, and PCOS pathogenesis in this understudied subgroup, potentially opening new diagnostic and therapeutic avenues.

Summary

The researchers compared 27 PCOS patients without hyperandrogenism (PCOS-N) to 23 non-PCOS controls, further split into normal-weight and obese subgroups. They measured plasma TMAO levels, inflammatory markers (via LEGENDplex flow cytometry panel), and metabolic indices (HOMA-IR, FINS, FBG, lipid profile). TMAO was quantified using LC-MS/MS. The study found TMAO levels were significantly elevated in PCOS-N patients, particularly the obese subgroup, and correlated with select inflammatory cytokines and BMI. Logistic regression identified TMAO and LH/FSH ratio as independent predictors of PCOS risk.

Key findings

  • Plasma TMAO, insulin levels, and HOMA-IR were significantly higher in PCOS-N patients, especially those who were obese.
  • IL-17A, IL-18, and IFN-γ were significantly elevated in obese PCOS-N patients (not in normal-weight PCOS-N).
  • TMAO correlated positively with BMI in normal-weight groups, and with IL-17A specifically in the obese PCOS-N group.
  • Logistic regression: TMAO (OR = 3.814, 95% CI 1.330–10.939, P=0.013) and LH/FSH (OR = 18.008, 95% CI 1.012–320.449, P=0.049) were independent predictors of PCOS.
  • No direct significant correlation was found between TMAO and insulin resistance (IR) itself — TMAO’s association appeared more tied to inflammation than IR directly.
  • Conclusion: Elevated TMAO may be linked to non-HA PCOS pathogenesis and systemic inflammation, warranting further research as a biomarker/therapeutic target.

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Citation

Huang J, Liu L, Chen C, Gao Y. PCOS without hyperandrogenism is associated with higher plasma Trimethylamine N-oxide levels. BMC Endocr Disord. 2020;20:3. https://doi.org/10.1186/s12902-019-0486-9

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