Endocrine Abstracts

Objective: Polycystic ovary syndrome (PCOS) affects 5–20% of women of reproductive age worldwide and is associated with disorders of glucose metabolism. Hormone and metabolic signalling may be influenced by phytoestrogens, such as isoflavones. Their endocrine effects may modify symptom penetrance in PCOS.

We investigated, whether women with PCOS and healthy controls differ in their capacity to metabolize dietary isoflavones and whether this capacity is associated with PCOS-typical metabolic, microbiome and predicted metagenomic markers.

Objectives: After clinical and biochemical characterisation, urine isoflavone levels were measured in PCOS and control women before and 3 days after a defined isoflavone intervention via soy milk. In parallel, bacterial equol production was evaluated using the log (equol:daidzein ratio) and microbiome, metabolic and predicted metagenome analyses were performed. Urine isoflavone and equol levels were measured by mass spectrometry in women with PCOS (n = 24) and non-PCOS controls (n = 20) before and after 3 days ofsoy challenge. Bacterial equol production was evaluated using the log(equol:daidzein ratio). Group size was calculated according to the effects of equol. Metagenome analyses were performed using PiCRUST (Phylogenetic Investigation of Communities by Reconstruction of Unobserved States), LEfSe (Linear discriminant analysis effect size) and QIIME1.9 (Quantitative Insights Into Microbial Ecology).

Results: We found metabolic changes, decreased glucose (P = 0.01) and fasting insulin (P < 0.01) as well as a decreasedrespective HOMA2-IR (P < 0.02) in PCOS patients, but not in control women (P = 0.48, P = 0.70, P = 0.72) after isoflavone intervention. Investigating the effect of an equol rise on androgenic as well as fertility markers, these two categories correlated negatively with the rise of equol (− 0.364, P = 0.021, −0.396, P = 0.021 resp.). In addition, we found PCOS-associated predicted metagenomic pathways improved after soy intervention with specific strains linked to carbohydrate metabolism as well as inflammation being increased in PCOS women but not in controls.

Summary and conclusions: There is increasing evidence on specific interactions between energy metabolism, hormone systems and bacterial pathways e.g. via active intestinal compounds. The importance of the equol producing gut microbiota and metagenomic pathway changes in PCOS women may therefore be considered from a new perspective. However, dietetic and microbiota-associated aspects in PCOS should be investigated in more detail in the near future.