P-647 Underlying mechanisms in clinical manifestations of polycystic ovarian morphology (PCOM) and PCOS women
Authors: Ramírez Martín N , Romeu M , Martínez J , Peinado I , Chico-Sordo L , Buigues A , Soriano M J , Pellicer N , Pellicer A , Herraiz S 
Published: June 2023

Study question

Does the D19S884 allele 8 (A8) equally affect the pathogenesis and ovarian gene expression of PCOS and PCOM patients?

Summary answer

A8-allele produces metabolic, endocrine, and ovarian alterations regardless diagnose. The mechanisms involved in PCOM alterations are different from those of the ovarian phenotype of PCOS.

What is known already

The specific D19S884 allele 8 of the FBN3 gene may be related to polycystic ovarian syndrome (PCOS) clinical manifestations. The A8 allele participates in alternative splicing of FBN3 and produces Asprosin-3, related to glucose modulation, and Fibrillin-3. Fibrilin-3 is an extracellular matrix protein, and together with a dysregulation of the Hippo pathway, could be responsible for constraining follicular growth in the PCOS ovaries. However, it is still unknown how these pathways act in PCOS, and whether these mechanisms are also involved in pathophysiology of polycystic ovarian morphology (PCOM) in apparently normal women with regular menses.

Study design, size, duration

Cross-sectional and descriptive study with 139 women (24-39 years-old) undergoing an IVF cycle between 2019-2022 at Hospital La Fe (Valencia, Spain). Thirty-one patients were considered PCOS, twenty-eight were classified as PCOM while the remaining eighty were controls. After recruitment women were screened for A8 allele, metabolic status, hormone profile, follicular fluid protein determination and expression of Hippo pathway and extracellular matrix genes. The IVF cycle parameters were recorded to determine their relationship with study variables.

Participants/materials, setting, methods

Women with two or more Rotterdam-criteria were considered as PCOS. PCOM patients were defined by polycystic ovarian morphology on ultrasound with regular ovulatory cycles. Genomic DNA was isolated from blood samples to assess the presence of A8 allele by capillary electrophoresis and FBN3 concentration was measured on follicular fluid by ELISA. TaqMan qPCR assay was used to analyze the expression of Hippo pathway (BIRC1 and CCN2) and extracellular matrix (ECM) genes in cumulus cells.

Main results and the role of chance

PCOS patients showed statistically significant metabolic and endocrine alterations with higher BMI, free androgen index (FAI), and glucose levels compared to controls. Despite having increased AMH levels (PCOS:45.0±21.7; PCOM:33.8±21.5; Control:17.6±7.19pmol/L, p &lt; 0.05), and AMH/AFC ratio (PCOS:1.9±0.9; Control:1.2±0.5, p = 0.008), PCOS showed lower fertilization rates (PCOS:64±26; Control:80±18%, p = 0.008), reduced good quality (PCOS:0.6±1.0; Control:1.3±1, p = 0.003) and transferred embryos (PCOS:1.3±0.9; Control:1.9±1.0, p = 0.018).

In PCOM, metabolic and androgen profiles were not different from controls. Although AMH, AFC (PCOM:24.4±13.7; Control:15.5±7.1, p = 0.007) and aspirated follicles (PCOM:17.3±5.7; Control:14.3±7.0, p = 0.026) were increased, fewer embryos were transferred (PCOM:1.2±1.1; Control:1.9±1.0, p = 0.027). PCOM women also showed ovarian downregulation of the Hippo-pathway (CCN2-PCOM:-4.8±10.8; Control:0.1±3.0, p = 0.010) and increased FBN3 concentration (PCOM:19.6±8.8; Control:14.7±5.6ng/ml, p=N.S).

The A8 allele was detected in 17% of our patients: 4% PCOS, 50% PCOM and 46% controls. Overall, A8 presence associated a Hippo-pathway downregulation (BIRC1-A8+:-2.7±4.5; A8-:0.3±2.2, p = 0.034) and increased ECM expression (EMILIN1-A8+:2.1±1.0; A8-:1.2±1.5, p = 0.04). Interestingly, in controls, higher glucose (A8+:95.1±6.7; A8-:83.5±10.1mg/dl, p = 0.002), cholesterol (A8+:182.5±11.1; A8-:165.4±27.3mg/dl, p = 0.029), LDL (A8+:117.8±10.4; A8-:83.9±29.4mg/dl, p = 0.002), and DHEAS levels (A8+:2633.0±670.7; A8-:1585.8±670.0ng/ml, p = 0.026) were found, consistent with a reduction in HDL (A8+:51.8±8.8; A8-:67.4±15.43mg/dl, p = 0.026) and a downregulation of the Hippo-pathway (BIRC1-A8+:-4.8±4.6; A8-:0.2±4.6, p = 0.013). In PCOM, A8+ promoted higher FAI (A8+:1.6±1.5; A8-:0.8±0.7, p=N.S), and less embryos obtained (A8+:5.9±3.8; A8-:10.7±3.8, p = 0.04).

Limitations, reasons for caution

Due to the low prevalence of A8 in our PCOS population, its effects cannot be evaluated in this group. Further validation of gene expression results by RNA-seq will be required to assess the broad spectrum of ovarian transcriptomic changes induced by both, the PCOM phenotype and the A8 allele.

Wider implications of the findings

Polycystic ovarian morphology is not unique to clinical disorder of PCOS and the triggering mechanisms appear to be distinct from those observed in women with regular cycles. Our findings suggest that the presence of A8 allele impacts on metabolic profile, androgen levels, and ovarian pathway dysregulations, despite the clinical diagnose.

Trial registration number

Not applicable