O-253 Altered telomerase activity in ovarian follicular cells in patients with polycystic ovary syndrome
Authors: Lamsira H  K , Pelligrini L , Bertani N , Maresca L , Galliano D , Pellicer A , Valensise H , Klinger F  G , Cozzolino M 
Published: July 2024

Abstract

Study question
Is telomerase machinery altered in cumulus and granulosa cells of patients with Polycystic ovary syndrome (PCOS) undergoing assisted reproductive treatment (ART)?

Summary answer
Patients with PCOS presented an altered expression of telomerase inhibitor factors TRF1 and TRF2 and shorter telomeres in cumulus cells (CCs) and granulosa cells (GCs)

What is known already
PCOS affects 6%-20% of fertile women; one of the most common features is represented by abnormal folliculogenesis, showing a higher number of follicles at all developmental stages. In PCOS, increased levels of reactive oxygen species (ROS) have been related to abnormal follicular development due to oxidative stress-induced DNA damage. Telomeres, present at the ends of the chromosomes, are essential for maintaining their stability during somatic cell proliferation. When guanine-rich telomeric repeats are exposed to oxidative stress including ROS, they undergo oxidative DNA damage that shortens telomeres in non-dividing cells like follicular cells, thereby potentially altering folliculogenesis.

Study design, size, duration
A prospective experimental study was conducted at IVIRMA Rome and University Unicamillus from September 2022 to January 2024. CCs and GCs were collected from the follicular fluid of patients undergoing in vitro fertilization (IVF). Twenty-eight patients with PCOS and. Thirty-one normal responders were included in the pilot study.

Participants/materials, setting, methods
Women with PCOS (n = 28), diagnosed according to the Rotterdam criteria, were included in the study. The healthy control group (CONT) included normal responders (n = 31) undergoing IVF. CCs and GCs were collected on the day of oocyte retrieval and subsequently used for immunofluorescence spot counting of TRF1 and TRF2. In addition, telomere length was measured using a specific kit. qRT-PCRs for TRF1, TRF2 and apoptotic marker BAX genes were performed and expressed as 2^-ΔCT values.

Main results and the role of chance
Immunofluorescence for TRF1 in the PCOS group presented a higher spot number in CCs compared to the CONT (9.90±0.23 vs 7.96±0.33, p = 0.0009) while TRF2 spots significantly decreased (8.85 ±0.24 vs 11.23±0.28; p = 0.0007). An increase of TRF2 gene expression was observed in CCs of the PCOS group when compared to CONT (0.0052±0.0006 vs 0.0030±0.0003; p = 0.062) no differences were found in the expression of TRF1 (0.0343±0.006 vs 0.026±0.047p=0.68; Bax was significantly increased (0.0139±0.001 vs 0.0102±0,0007 p = 0.007) and telomeres have a shortening trend (0.36±0.36 vs 1±0 p = 0.74).
In GC a lower number of TRF1 spots in PCOS vs CONT was observed while TRF2 had just an increasing trend (11.16± 0.586 vs 11.70 ± 1.99, p = 0.61; 16.79 ± 3,85 vs 11.34 ± 0.588; p = 0.68). In GCs of PCOS group vs CONT there was an increase in TRF2 gene expression (0,007 ± 0,001 vs 0.003 ± 0.0004; p = 0.03) and no differences were found in TRF1 (0.032± 0.003 vs 0.003± 0.012 p = 0.25). Ultimately Bax was increased in GCs of PCOS samples vs CONT (0.018 ±0.002 vs 0.011 ±0.0005 p = 0.0006) and the telomeres were significantly shorter (0.0246± 0.0349 vs 1± 0 p &lt; 0.0001).

Limitations, reasons for caution
A limited number of samples were analyzed in the study and different PCOS sub-phenotypes were not considered. The analysis of CCs could be uninformative due to inter-individual variability in the PCOS sub-phenotypes within the same study group.

Wider implications of the findings
These findings demonstrate that PCOS patients present a higher expression of telomerase-inhibiting factors TRF1 and TRF2, undergo apoptosis and have significantly shorter telomeres supporting the theory that abnormal folliculogenesis in PCOS affects telomere length, therefore shedding new light on this medical condition and possibly explaining its clinical and biochemical features.

Trial registration number
not applicable