Browsing by Author "Leal, Carla"
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- Cumulus cell DNA damage linked to fertilization success in females with an ovulatory dysfunction phenotypePublication . Rodrigues, Bárbara; Sousa, Vanessa; Esteves, Filipa; Vale-Fernandes, Emídio; Costa, Solange; Sousa, Daniela; Brandão, Raquel; Leal, Carla; Pires, Joana; Gaivão, Isabel; Teixeira, João Paulo; Nogueira, António J.A.; Jorge, PaulaIntracytoplasmic sperm injection (ICSI) is a widely used technique in fertility centers. ICSI success depends on both nuclear and cytoplasmic oocyte maturation. Cumulus cells, which surround the oocytes, play a pivotal role in oocyte competence. However, the significance of DNA damage in cumulus cells as a marker of fertilization success remains largely unexplored. This study aims to investigate the relationship between DNA damage in cumulus cells of females undergoing ICSI, and oocyte competence, with a focus on in vitro fertilization (IVF) outcomes. We employed the alkaline comet assay to assess DNA damage levels (%TDNA) in cumulus cells and whole blood from 22 potentially fertile females and 35 infertile females, including 20 with an ovulatory disfunction phenotype. Our results revealed significant differences between the levels of %TDNA in cumulus cells and blood. Females with an ovulatory dysfunction phenotype exhibited higher levels of %TDNA in cumulus cells compared to potentially fertile females. Additionally, within the group of females with ovulatory dysfunction, a significant correlation was observed between %TDNA levels and the number of oocytes with two pronuclei. Our findings suggest that blood does not accurately reflect DNA damage in cumulus cells, which was correlated with the fertilization success in females with ovulatory dysfunction. High levels of %TDNA in cumulus cells were associated with a higher likelihood of successful fertilization. Moreover, our results imply that low levels of %TDNA may be linked to oocytes that fail to complete maturation and, consequently, do not fertilize (oocytes with zero pronuclei). Further research with larger cohorts is necessary to validate these findings and to explore potential applications in female fertility. However, our study provides evidence that DNA damage in cumulus cells may serve as a valuable biomarker for predicting fertilization success and oocyte competence.
- Cumulus cells damage can help to indirectly predict oocyte quality in infertile females undergoing ICSIPublication . Rodrigues, Bárbara; Sousa, Vanessa; Esteves, Filipa; Pires, Joana; Sousa, Daniela; Brandão, Raquel; Leal, Carla; Santos, Rosário; Vale-Fernandes, Emídio; Nogueira, António; Costa, Solange; Jorge, PaulaIntroduction: Intracytoplasmic sperm injection (ICSI) is currently used in clinical practice for couples with fertility issues. Some studies have shown an association between male reproductive ability and sperm DNA damage levels, assessed by comet assay. However, little is known regarding this endpoint and female fertility, mostly due to tissue accessibility. To overcome this, we used cumulus cells (CC) to analyze DNA damage in search of correlation with clinical parameters evaluated in the context of infertility. Methodology: DNA damage was assessed via comet assay, in two different tissues, blood and CC, from females undergoing ICSI: 22 potentially fertile and 35 infertile. DNA damage levels (%TDNA) were compared between the two groups (fertile vs infertile), and correlated, within each group, with hormone levels, stimulation days, number of cumulus-oocyte complexes (COCs) retrieved, and oocytes injected. All analysis were performed using SigmaPlot version 14.0 (Systat Software®Inc., Chicago, IL, United States). Results: No significant differences were found in %TDNA levels between the 2 groups. However, the DNA damage observed in CC was notably increased in the infertile females when compared to the potentially fertile, although it did not reach statistical significance. Interestingly, %TDNA in CC was significantly correlated with the number of oocytes injected, in both groups. This finding was not observed in the blood. Moreover, the difference between number of COCs retrieved and oocytes injected was significantly higher in the infertile females group and showed a correlation with the damage observed in CC. Discussion: Our results established a correlation between DNA damage in CC and oocyte quality. CC support and nurture oocytes during development, but DNA damage in CC can predict a reduced oocyte quality and availability for injection. This finding underscores the importance of CC in oocyte development and emphasizes the need to consider tissue-specific effects in DNA damage studies, particularly those related to fertility and reproductive health. Nevertheless, further studies are needed to confirm our results.