ESPE Abstracts

Background and Methods: PCOS is common in adolescents and imparts a significant health and economic burden. Yet, our understanding of its complex pathogenesis is lacking. Proteomic analyses would be a valuable tool to deepen our knowledge of the biological pathways which underpin PCOS, and to identify novel biomarkers to diagnose and monitor this common condition. Therefore, we undertook a deep phenotyping discovery proteomic profiling (nano-2D-LC-QTOF MSe) on urine samples from 15 participants from a longitudinal adolescent PCOS cohort of 40 participants. We compared the urinary proteome of adolescents with PCOS, insulin resistance (IR), and controls. Subsequently, we validated these omic results in the entire adolescent cohort, and an adult PCOS cohort, by running an in-house, multiplexed, targeted proteomic panel of 89 known inflammatory-associated proteins.

Results: In the discovery urine proteomic analysis, we identified 3,793 proteins, of which, 66 were differentially expressed in the PCOS cohort in comparison to both IR and controls. As such these form a pool of potential biomarkers for PCOS. Bioinformatic analysis revealed that almost half of all biological pathways which significant proteins were involved in, were related to inflammatory/immunological responses and the thrombotic/fibrinolytic systems. The inflammatory response was the most significant biological process associated with PCOS (P<0.001). This association was validated using targeted proteomic analysis of inflammatory-associated proteins. Multivariate analysis demonstrated that there were differences between the inflammatory proteome of adolescent PCOS, IR, and control cohorts. Differences were identified at the proteome-level between adolescents and adults with PCOS. However, greater differences were identified between individual inflammatory-associated proteins. In total, 11 inflammatory-associated proteins were upregulated in the adolescent PCOS cohort in comparison to either IR or control cohorts, and eight proteins were downregulated. Of these, four proteins were significantly different in the PCOS cohort in comparison to IR and control cohorts, making them potential candidate biomarkers for PCOS in adolescence. When comparing the proteome of adolescents and adults with PCOS, four proteins were identified as being similarly up- or downregulated in both PCOS cohorts in comparison to their age-matched controls. As such, these form a potential pool of PCOS biomarkers which may be clinically useful across the reproductive lifespan, from adolescence, into adulthood.

Conclusions: These analyses have provided vast data exploring the pathophysiology of PCOS, and strongly suggest that inflammatory processes play a crucial role. Several proteins of interest have been identified in urine, which have the potential for use as non-invasive biomarkers for PCOS.