From the Journals

PCOS may influence the diversity of the gut microbiome

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Shedding light on PCOS provides opportunity for new treatments.

Polycystic ovarian syndrome (PCOS) can manifest itself in many ways, but this study reveals that it can directly affect the metabolism of those who have the disorder.

“We’re still early days in studying this, but this study suggests that one of the clinical characteristics of these women with this disorder – their elevated testosterone – is correlated with changes in the gut microbiome,” Varykina G. Thackray, PhD, of the department of reproductive medicine and the center for reproductive science and medicine at the University of California, San Diego, said in an interview. “That means that these women are in a different group than other people with metabolic disorders, and it potentially gives us a way to think of new therapies that might be helpful for this specific group of women.”

Dr. Varykina Thackray

Metabolic symptoms affect about 80% of those with PCOS and are generally not as well understood as the fertility issues associated with the disorder. These issues can range from obesity to diabetes and insulin resistance and can have serious effects on an individual’s health. This study shows that the changes in the gut microbiome may be contributing to some of these metabolic disturbances in women with PCOS. Dr. Thackray stated that finding a way to help restore the gut microbiome may be a potential way to help treat PCOS-associated metabolic issues.

When asked whether fecal transplants may be a potential therapy to help treat the metabolic issues associated with PCOS, Dr. Thackray stated that she did not believe a lot of women would use that as a therapy because of the “ick” factor. She stated the goal is to identify some beneficial bacteria that could be taken as a probiotic to help restore the gut microbiome.

Unfortunately, researchers still do not understand what causes PCOS. Some studies suggest that there are environmental and genetic factors, but there is nothing definitive. Dr. Thackray stated that getting more funding and conducting more research are the best ways to understand and combat this disorder.

Dr. Thackray is an associate professor of reproductive medicine at the University of California, San Diego.



The diversity of gut microbiota in women with polycystic ovary syndrome (PCOS) is much less diverse, a problem which may be caused by androgen levels, according to a study from the Journal of Clinical Endocrinology and Metabolism.

“This study demonstrated that Caucasian women diagnosed with PCOS using the Rotterdam criteria had a reduction in overall species richness [alpha diversity] of the gut microbiome, compared to healthy women, and changes in the composition of the microbial community [beta diversity]” wrote Pedro J. Torres and his associates. “Interestingly, our study found that the biodiversity of the microbiome strongly correlated with hyperandrogenism.”

Dr. Torres of the University of California, San Diego, and his colleagues recruited 163 women at the University of Poznan (Poland) and conducted analysis on fecal samples to determine the effects of PCOS on the gut microbiome. Each woman underwent a battery of tests to determine whether she had PCOS or polycystic ovarian morphology (PCOM). Ovarian morphology was determined from a transvaginal ultrasound evaluation. The women were assessed for body mass index and hirsutism. Blood samples were taken to test for hormonal abnormalities common with PCOS and metabolic issues, like type 2 diabetes mellitus and glucose tolerance. Fecal samples were taken to analyze the gut microbiota of each study participant; analysis of the fecal samples generated gut microbial diversity profiles for each of the 163 women. Analysis of the samples was conducted at the University of California, San Diego.

Of the subjects, 48 were healthy, 42 had PCOM, and 73 were diagnosed with PCOS. The researches noted that, compared with healthy women and those with PCOM, women with PCOS had higher levels of serum total and free testosterone, as well as higher rates of hirsutism and fewer menses per year. These women also had higher levels of serum luteinizing hormone and increased ratios of luteinizing hormone to follicle stimulating hormone.

The DNA analysis of fecal samples yielded 481 sequence variants from the fecal swabs. Women with PCOS were found to have lower alpha diversity in their gut microbiome, as evidenced by abundance (P = .04) and Faith’s phylogenetic diveristy (P = .02). The luteinizing hormone to follicle stimulating hormone ratio also appeared to affect the alpha diversity of women with PCOS, as seen in observed sequence variants and Faith’s phylogenetic diversity (P = .08).

Beta diversity analysis, or the biodiversity between samples, revealed that hyperandrogenism could be a primary driver of changes in the gut microbiome. Using permutational multivariate analysis of variance, researchers determined that hyperandrogenism significantly affected beta diversity (P = .0009).

Androgens may help affect the gut microbiome in important ways, and changes in the gut microbiome may influence how the pathology of PCOS develops, according to Mr. Torres and his colleagues; however, more studies should be conducted to determine the effects of androgens on the gut microbiome.

“If hyperandrogenism drives the microbial composition of the gut, it would be interesting to determine if treatment of PCOS with androgen antagonists or oral contraceptives results in recovery of the gut microbiome and improvement of the PCOS metabolic phenotype” wrote Mr. Torres and his colleagues. “Moreover, it would be informative to determine whether the gut microbiome of women diagnosed with PCOS using the criteria of oligomenorrhea and polycystic ovaries is distinct from that of women diagnosed with the other subtypes of PCOS that include hyperandrogenism.”

The authors had no relevant financial disclosures to report.

SOURCE: Torres PJ et al. J Clin Endocrinol Metab. 2018 Jan 23. doi: 10.1210/jc.2017-02153.

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