Identifying Expression Markers of Cumulus Cells to Identify Oocyte Developmental Potential Through a Maturation Analysis

Identifying Markers of Oocyte Competence Through a Maturation Analysis

The aim of the study is to analyze the expression of genes and microRNAs potentially involved in oocyte competence in follicles of different sizes (<17mm and ≥17mm) at the time of oocyte pick-up.

In ART, one of the major obstacles encountered in some patients is the wide variation in the follicular size at the oocyte pick-up day and consequently, the number of available mature oocytes and the number of competent embryos for implantation. The follicular size at the day of oocyte pick-up reflects the synchronicity of the individual follicular responsiveness to FSH.

For successful preimplantation development of an embryo, the oocyte must contain all necessary maternal factors. Two of these factors are specific mRNA transcripts (GDF9, PTX3, HAS2, PTGS2, TNFAIP6) and microRNA (miR-224).

For each Cumulus Oocyte Complex, the evaluation of embryo development and morphokinetics will be correlated with the expression and implantation data to identify a quantitative biomarker to predict the embryo with the highest chance of implantation in patients.

Experimental Design:

1. - Collection of Cumulus Oocyte Complex (COC) from patients
2. - Separation of oocytes according to the size of the follicule they have been retrieved from (<17mm; ≥17mm)
3. - Isolation of mRNA from both groups of cumulus cells
4. - Expression studies, qRT-PCR (GDF9, PTX3, HAS2, PTGS2, TNFAIP6)
5. - Analysis of miR-224, a negative regulator of cumulus expansion via PTX3
6. - Time-lapse culture & evaluation of morphokinetics

Inclusion Criteria:

• No more than 2 previous treatment cycles
• No history of recurrent spontaneous abortions
• Age ≤ 39 years
• BMI < 30 kg / m2
• ≥ 8 cumulus-oocyte-complexes (COC) retrieved
• human Chorionic Gonadotrophin (hCG) triggering

Exclusion Criteria:

• Preimplantaion Genetic Diagnosis (PGD) or Preimplantation Genetics Screening (PGS) indication
• Maximum number of 24 COC during pickup
• Failure to culture until Day 5
• Polycystic ovary syndrome
• Severe endometrial factor that can influence implantation
• Uterine malformation or congenital anomaly
• Severe male factor (Azoospermia)