Póster Congreso ESHRE20: Selecting spermatozoa with the highest chromatin integrity

  • Fecha: July 2020. Congreso ESHRE 2020
  • Revista: ESHRE 2020
  • Autores: J. Stewart, A. Parrella, D. Tavares, M.S. Wang, M. Haddad, Z. Rosenwaks, G.D. Palermo.


Study question: What is the impact of selecting spermatozoa with the highest chromatin integrity on ICSI outcomes?

Summary answer: We selected spermatozoa with the highest progressive motility and chromatin integrity by microfluidic sperm selection (MFSS) and achieved superior implantation and delivery rates.

What is known already: Sperm preparation methods aim at providing specimens for insemination with the highest progressive motility independent of phenotypic and genomic integrity. It has recently been recognized that a microfluidics device yielded spermatozoa with the highest progressive motility as well as superior chromatin integrity. Here we compared two sperm selection methods: density gradient centrifugation (DGC) and MFSS.

Study design, size, duration: From October 2016 to January 2020, ejaculates that were processed by DGC and MFSS for ICSI treatment from 8 consenting men were screening for DNA fragmentation by TUNEL. In addition, ejaculates from 22 men were processed solely by MFSS for ICSI treatment. Semen parameters, chromatin integrity, embryo implantation, and pregnancy characteristics were compared.

Participants/materials, setting, methods: Fresh ejaculated specimens from consenting men were collected for standard semen analysis in accordance with WHO 2010 criteria. DGC and MFSS were used to isolate motile spermatozoa based on cell motility and fluid dynamics. Sperm chromatin fragmentation (SCF) was assessed by terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) on at least 500 spermatozoa under a fluorescent microscope utilizing a threshold of ≥15%. ICSI was performed in the standard fashion.

Main results and the role of chance: A total of 20 men (43±6 years) had the following average semen parameters: concentration of 18±15 x 106/mL, 30±18% motility, and 2.4±1% morphology. After DGC and MFSS, the sperm concentration was 2.2±1 and 1.5±12.6 x106/mL, with 49±32% and 97.4±5% motility, respectively (P<0.0001). The morphology of the raw sperm sample improved from 2.3±1% to 4.0±1% after MFSS, while it remained at 2.6±1% after DGC. In 8 men (43±6 years), the SCF in their raw sample was 23%, falling to 18% after DCG selection and to 1.2% after MFSS (P < 0.0001). They underwent 20 ICSI cycles with their female partners, (37±3 years) with DGS sperm selection, achieving a 58% fertilization rate (80/138). The implantation rate was 5% (2/41) with an 11% clinical pregnancy rate (CPR) (2/18) and one pregnancy loss. Subsequently, ICSI with MFSS achieved a fertilization rate of 65%, a 29% (5/17; P<0.01) implantation rate, and a 63% (5/8; P<0.001) CPR. An additional 22 men (43±7 years) underwent 28 ICSI cycles solely with MFSS due to poor reproductive history. A 76% fertilization rate (203/266) and 54% (31/57) good quality embryos were achieved. The implantation rate was 26% (15/57) with a 50% CPR (13/26).

Limitations, reasons for caution: This is a preliminary study on a small number of subjects. Although we controlled for a concurrent female factor, this cannot be excluded with certainty. As this is a new method, the health of the resulting offspring would need to be evaluated to confirm the safety of the technique.

Wider implications of the findings: According to our study, SCF appears to be linked to the kinetic characteristics of the sperm cell. This novel microfluidic device may help to identify spermatozoa with the highest functional and genomic integrity and ultimately be routinely used in ART treatments.