P-082 Microfluidic-based device selects sperm with less DNA damage and higher motility, what else?
Authors: Pardiñas Garcia M.L , De los Santos J.M , Viloria T , Ortega-Jaen D , Martin A , De los Santos M.J 
Published: June 2022

Abstract

Study question
Does the microfluidic-based sperm selection device ZyMōt improve sperm parameters and other laboratory key performance indicator (KPI) values compared to the conventional swim-up method?

Summary answer
The microfluidic-based sperm selection device ZyMōt selects sperm with lower DNA fragmentation and higher motility than conventional swim-up method in intracytoplasmic sperm injection (ICSI) cycles.

What is known already
Elevated levels of sperm DNA fragmentation (SDF) in semen samples have been associated with poor embryo development and low pregnancy rates. SDF refers to breaks in the sperm's genetic material, mainly due to defects during spermatogenesis and other factors such as reactive oxygen species that are favored by centrifugation. Conventional sperm selection methods, by integrating centrifugation into their protocols, have become ineffective in selecting sperm with low SDF. In order to solve this problem and improve reproductive outcomes, microfluidic-based devices such as ZyMōt have been designed to avoid centrifugation and select spermatozoa with low SDF.

Study design, size, duration
Prospective, experimental, single-center study conducted from June to December 2021. A total of 14 couples with ≥ 10 retrieved oocytes were recruited for an intra-patient comparison. Semen sample was split and processed for ICSI by the conventional swim-up method or by the microfluidic-based device ZyMōt. Each fraction was used to fertilize half of the total number of oocytes retrieved. SDF index, semen parameters, useful blastocyst rate, fertilization rate and morphokinetic variables were observed.

Participants/materials, setting, methods
Oocytes retrieved were from own (n = 96) and donation cycles (n = 93). From each patient, the cohort of oocytes was divided into two groups: 1) inseminated with spermatozoa selected by swim-up and 2) inseminated with spermatozoa selected by ZyMōt 850 µL device. Embryo evaluation and development were then followed by time-lapse monitoring using EmbryoScope. Sperm chromatin dispersion (SCD) assay was used to measure SDF, analyzed by ImageJ. Each treatment followed routine protocol established in the clinical practice.

Main results and the role of chance
SDF index was significantly lower in ZyMōt group in comparison with swim-up group (10% vs 20%), indicating a better selection by the ZyMōt of sperm with less DNA breaks. Additionally, ZyMōt group also presented a significantly greater number of spermatozoa with progressive motility (96.9% vs 95.4%). In contrast, useful blastocyst rate showed a slightly, but not significantly, increment in ZyMōt group compared to swim-up group (53.2% vs 46.6%). No significant differences in fertilization rate or sperm recovery rate were observed between groups. Regarding morphokinetic parameters, timing variables from first cell division to blastocyst stage (t2-tB) showed no significant correlation with ZyMōt group contrasted with swim-up. Blastocysts were evaluated and a value was assigned with respect to their quality (A to D). There was a higher number of embryos with A grade in ZyMōt group and a higher number of embryos with D grade in swim-up group. The annotated variables were assessed using paired t-test and P value &lt;0.05 was considered statistically significant.

Limitations, reasons for caution
The impact on reproductive outcomes may vary depending on whether the breakage is single- or double-stranded, however, SCD is not able to distinguish between them. These, together with the oocyte's ability to repair sperm damage, lead us to the explanation for the non-significance on embryo quality.

Wider implications of the findings
This study provides further insights into the use of ZyMōt for the selection of low SDF spermatozoa in a simple manner. Its use could be indicated in patients with a high SDF value in their semen samples. Benefits on reproductive outcome will be confirmed with larger sample size.

Trial registration number
2102-VLC-007-MD