P-058 The role of sperm selection in improving embryo euploidy rate: a comparison between Swim-up and Microfluidic Sperm Selection
Authors: Paccagnini D , Barberi M , Nucera C , Musella M , Uva D , Zazzaro V , Listorti I , Greco E 
Published: July 2024

Abstract

Study question
Does Microfluidic Sperm Selection (MSS) improve the blastocysts’ development rate and the euploidy rate compared to Swim-up sperm selection?

Summary answer
MSS doesn’t improve the rate of blastocyst development and euploidy compared to Swim-up. Furthermore, in women age ≥ 37 years D6 aneuploid blastocyst rate increases

What is known already
Sperm defects have been shown to have a negative impact on embryo quality and development. MSS was introduced as an alternative to traditional centrifugation-based sperm preparation techniques to efficiently isolate highly motile and healthy spermatozoa. Centrifugation has been suggested to compromise membrane integrity, motility, mitochondrial energy production, and DNA structure. Less DNA fragmentation and ROS formation was observed in spermatozoa isolated with MSS compared to standard techniques. Our study aims to analyze whether MSS also improves biological outcomes.

Study design, size, duration
In a prospective study of 51 ICSI/PGT-A cycles performed between September 2022 and November 2023, freshly ejaculated semen sample was divided into two aliquots and processed by Swim-up and MSS. Split sperm sample was used to inject siblings’ mature oocytes (249 vs 274 oocytes in Swim-up vs MSS groups). Inclusion criteria: retrieved MII oocytes ≥8, oligoteratozoospermic and normozoospermic semen. Results were analyzed according to women’s age &lt;37 years (21 cycles) and ≥37 years (30 cycles).

Participants/materials, setting, methods
Spermatozoa were selected using either conventional Swim-up or a microfluidics device (ZyMōtTM). Post treatment sperm parameters (sperm count; total sperm motility; progressive motility and hyperactivated motility) were examined for both. Embryo culture was performed in Irvine Continuous Culture-NX media until day5 or day6 and biopsy was performed at the blastocyst stage by next generation sequencing. Primary endpoint was fertilization rate, blastocyst development and usable blastocysts rate. Chi-square analysis was performed and p &lt; 0.05 was considered significant

Main results and the role of chance
There is no significant differences overall between Swim-up and MSS in fertilization rate (73% vs 75%), blastocyst development rate (47% vs 54%) and ploidy rate: aneuploid (47% vs 50%), usable blastocyst (i.e. euploid+mosaics) (53% vs 50%). When considering female age, no significant difference is observed in the primary endpoints in the &lt;37 years group. However, in women aged ≥37 years, the rate of blastocyst development is similar in the two sperm preparation groups, but a significant difference is observed in the timing of blastocyst development: The percentage of blastocysts formed on day 6 in the MSS group is significantly higher than in the Swim-up group (43% vs. 19% p &lt; 0.05). In addition, the aneuploidy rate of blastocysts on day 6 is also significantly higher than in the Swim-up group (79% vs. 50% respectively, p &lt; 0.05). The concentration of sperm recovered post-treatment was similar in Swim-up vs MSS (23 x106 vs 19 x106); total motility and progressive motility were similar in Swim-up compared to MSS (92.7% vs. 95.3% and 85% vs. 87% respectively). Only hyperactivated motility assessed with the SCASCOPE CASA System (Microptic) was significantly higher in MSS vs Swim-up 41% vs 4% respectively (p &lt; 0.0005).

Limitations, reasons for caution
Our study included couples with different infertility diagnosis and semen parameters. Further studies with an increased number of patients may provide more comprehensive data to better evaluate biological and clinical outcomes to eventually suggest the use of MSS in laboratory routines

Wider implications of the findings
Recently, some studies reported that microfluidic-sorted sperm showed significantly less ROS formation and DNA fragmentation compared to those treated with conventional Swim-up method. Nevertheless, our data does not currently show the expected increase in embryo euploidy rate to justify the routine use of these expensive devices in male infertility treatment

Trial registration number
non applicabile