Alteration in gut mycobiota of patients with polycystic ovary syndrome Original paper

What Was Studied?

This study examined the composition and function of the gut mycobiota in women with polycystic ovary syndrome (PCOS), a condition primarily explored through bacterial profiling in prior research. The authors aimed to fill a critical knowledge gap by focusing on the fungal component of the gut microbiome, which has increasingly been recognized as a modulator of immune responses and metabolic regulation. Using internal transcribed spacer (ITS) sequencing, they compared fecal fungal communities in 17 PCOS patients and 17 age-matched healthy controls. Functional profiling through PICRUSt2 enabled prediction of metabolic pathways associated with the altered mycobiota. The study’s objective was to determine whether PCOS is associated with fungal dysbiosis and to identify fungal genera that may influence metabolic, immune, or hormonal dysregulation in PCOS pathophysiology.

Who Was Studied?

Seventeen women diagnosed with PCOS based on the 2003 Rotterdam criteria were recruited from a hospital in Northeast China and compared with 17 healthy controls. The two groups were matched for age but differed significantly in body weight and BMI, consistent with typical PCOS presentations. PCOS participants had elevated levels of luteinizing hormone, testosterone, fasting insulin, triglycerides, and other markers indicative of endocrine and metabolic dysfunction. Fecal samples from all participants were collected and analyzed for fungal composition, and serum hormone profiles were assessed to correlate gut mycobiota shifts with systemic alterations.

What Were the Most Important Findings?

This study revealed that women with PCOS exhibit marked fungal dysbiosis in their gut microbiota. PCOS patients had significantly lower alpha diversity, as shown by Shannon and Simpson indices, and distinct fungal community structures as demonstrated by β-diversity analyses. At the phylum level, there was a consistent increase in Ascomycota and a reduction in Basidiomycota in PCOS patients. At the genus level, Saccharomyces, Candida, Zygosaccharomyces, Monascus, and Lentinula were significantly enriched, while Aspergillus, Asterotremella, Trichomonascus, and Cryptococcus were depleted. Notably, Saccharomyces and Lentinula were the dominant fungal taxa in PCOS, whereas Aspergillus, which may exert anti-inflammatory and probiotic-supporting effects, was significantly underrepresented.

Functionally, the fungal taxa enriched in PCOS patients contributed to altered pathways involving ceramide glucosyltransferase, uroporphyrinogen-III synthase, and dextransucrase, among others. These functional predictions suggest that gut fungi in PCOS may be involved in modulating host metabolism, immune signaling, and gut barrier function. Saccharomyces overgrowth, previously associated with immune activation and increased intestinal permeability, may exacerbate inflammation and metabolic stress in PCOS. Lentinula, typically a source of immune-stimulating β-glucans, may shift from immunomodulatory to pro-inflammatory roles under dysregulated conditions. In contrast, the depletion of Aspergillus—a β-galactosidase-producing genus linked to probiotic growth and anti-diabetic activity—may remove protective influences from the gut environment.

What Are the Greatest Implications of This Study?

This study introduces a compelling new dimension to PCOS pathogenesis by demonstrating that fungal dysbiosis, not just bacterial, plays a potentially significant role in disease expression. For clinicians, the findings underscore the need to expand microbiome diagnostics beyond bacterial sequencing, particularly in metabolically complex conditions like PCOS. The identification of Saccharomyces and Lentinula as enriched taxa, and Aspergillus as depleted, offers potential fungal biomarkers for disease stratification or treatment response. These fungal alterations may drive systemic inflammation, disrupt gut barrier integrity, and interfere with hormonal and metabolic signaling.

Therapeutically, the results open up new avenues for interventions aimed at modulating the gut mycobiome. Strategies may include antifungal probiotics, dietary modifications to reduce fungal overgrowth, or fungal metabolite targeting. Additionally, the study paves the way for interkingdom microbiome approaches that account for fungal-bacterial interactions, which may be particularly important in developing combination therapies for PCOS. These findings encourage integrative research into the gut–ovary axis that includes fungi as primary actors rather than passive bystanders.