Proteomic Analysis of Follicular Fluid in Polycystic Ovary Syndrome: Insights into Protein Composition and Metabolic Pathway Alterations.

This study explores the proteomic composition of follicular fluid (FF) from women undergoing oocyte retrieval for in vitro fertilisation (IVF), with a focus on the effects of polycystic ovary syndrome (PCOS). FF samples were collected from 74 patients, including 34 with PCOS and 40 oocyte donors. Proteomic profiling using machine learning identified significant differences in protein abundance between the PCOS and control groups. Of the 484 quantified proteins, 20 showed significantly altered levels in the PCOS group. Functional annotation and pathway enrichment analysis pointed to the involvement of protease inhibitors and immune-related proteins in the pathophysiology of PCOS, suggesting that inflammation and immune dysregulation may play a key role. Additionally, HDL assembly was identified as a significant pathway, with apolipoprotein-AI (APOA1) and alpha-2-macroglobulin (A2M) as the major proteins involved. Notably, myosin light polypeptide 6 was the most downregulated protein, showing the highest absolute fold change, and may serve as a novel independent biomarker for PCOS.