To determine the euploid rate relationship between aspirated and ejaculated sperm-sourced embryos
Materials and Methods:
Trophectoderm biopsy and PGS screening were performed on Day 5, 6 and 7 embryos were tested over a 2 year period. Biopsied embryos were segregated into based on sperm source: Percutaneous Epididymal Sperm Aspiration (PESA), testicular sperm aspiration (TESE) or ejaculated sperm. The euploid rates were retrospectively observed and compared. Oocytes were fertilized using intracytoplasmic sperm injection (ICSI) and embryos were cultured for up to 7 days in Continuous Single Culture Medium (Irvine Scientific). High quality blastocyst embryos exhibiting tightly bound inner cellular mass (ICM) and good quality trophectoderm were subsequently biopsied on days 5, 6 and 7. Biopsied samples were analyzed using next generation sequencing (NGS) was used to determine euploid status. Embryos were vitrified using Vit Kit (Irvine Scientific) for subsequent transfer.
Overall 992 embryos were biopsied from 1/2016 until 12/2017 (751 ejaculated sperm, 114 TESE, and 127 PESA sperm-sourced embryos) yielding an overall euploid rate of 49.7% (493/992). Euploid rates per group were 50% (374/751) for ejaculated sperm, 57% (65/114) for TESE and 43% (54/127) for PESA. Chi-square statistical analysis displayed that PESA sperm embryos resulted in significantly lower euploid rate when compared to TESE sperm rates (p=0.0246). Ejaculated sperm euploid rate was not found to be significantly different between TESE and PESA. Complex abnormal rates were 9% (18/196) for ejaculated sperm, 7% (5/67) for TESE, 14% (15/104) and for PESA; these results were not significantly different from each other.
Micro-surgical sperm aspiration procedures (PESA and TESE) followed by ICSI and PGS are all suitable approaches for treating azoospermia (Weng, 2014). The choice of surgical procedure is based on the cause of azoospermia: non-obstructive azoospermia (NOA) or obstructive azoospermia (OA). NOA often requires extracting testicular spermatozoa, which are fragile, non-motile, and have not undergone chromatin condensation. OA can be treated with a less invasive procedure to extract sperm from the epididymis, which are more durable, mostly motile, and have completed or are currently undergoing meiotic maturation. Embryos sourced from testicular sperm resulted in a significantly higher euploid rate than those from epididymal sperm. These data suggest that, in some patients, maturation of sperm through the epididymis may alter DNA during chromatin condensation. This, in turn, can cause an abnormal random assortment during fertilization causing a potential higher propensity of aneuploidy in the developing embryo. Our findings suggest that sperm retrieved prior to further maturation in the epididymis, may be more effective to treat male patients with azoospermia. Further investigation is needed evaluate reasons for requiring aspirated sperm, as well as pregnancy outcomes.