Improved PCOS Symptoms Correlate With the Composition of Gut Bacteria

PCOS affects about 10 percent of women of childbearing age, and the exact causes are often unknown. In a study of a mouse model, it was shown that the symptoms of polycystic ovary syndrome improved with exposure to healthy bacteria in the gut. This study from the University of California San Diego School of Medicine in La Jolla, California, builds on recent work by the same researchers showing that the human gut microbiome, or bacterial composition of the gut, is less diverse in women with PCOS. The results suggest that altering the gut microbiome through prebiotic or probiotic therapies could be a possible treatment option for PCOS.

Hormone Disorder Affects Health

In most cases, PCOS occurs between the ages of 20 and 30. The ovaries of women with PCOS produce too many male sex hormones, which is why the hormone balance is disrupted. Typically, cysts form on the ovaries. There is no cure for this hormone disorder, but the symptoms can be treated and alleviated with medication and a change in diet and exercise. Signs of the condition include cystic follicles in the ovaries, high testosterone levels, excess body hair, irregular or absent periods, and sometimes weight gain and insulin resistance. Possible long-term health consequences include infertility, miscarriage, pregnancy complications, type 2 diabetes, high blood pressure and depression.

How Certain Gut Bacteria Contribute to PCOS

Thackray and her research team induced PCOS in female mice that were going through puberty by administering letrozole, an aromatase inhibitor, to them. By blocking the conversion of testosterone to estrogen, this drug leads to increased testosterone levels and, in mice, to other signs of PCOS. Another control group of mice received a placebo treatment in this study, which was funded by the National Institute of Child Health and Human Development. For five weeks, the researchers kept two mice per cage in three different types of accommodation: PCOS mice together, placebo-treated mice together, and mice from both treatment groups together.

The researchers explained that the shared accommodation causes them to be exposed to each other’s gut microbiome. PCOS mice that lived with placebo-controlled mice had significantly improved testosterone levels, normalized cycles, and normalized ovulation compared to PCOS mice that lived with other PCOS mice. In addition, PCOS mice that were placed with placebo mice had lower weight, lower fasting blood glucose and insulin levels, and lower insulin resistance (a major risk factor for type 2 diabetes). The researchers suggested that these improvements in PCOS symptoms were related to changes in the gut microbiome. Further research is needed to understand how certain gut bacteria contribute to PCOS and whether the gut microbiome offers potential avenues for treating the condition.