Can a sperm selection technique improve embryo ploidy?

Area of Science:

• Reproductive Medicine
• Genetics
• Embryology

Background:

• Elevated sperm chromatin fragmentation (SCF) is linked to impaired conceptus development and implantation.
• The causal mechanism connecting SCF to poor embryo development remains unclear.
• Microfluidic sperm selection (MFSS) yields motile sperm with higher genomic integrity, potentially reducing SCF.

Purpose of the Study:

• To investigate the relationship between sperm chromatin fragmentation (SCF) and high embryo aneuploidy rates.
• To evaluate microfluidic sperm selection (MFSS) as a treatment option for improving IVF/PGT-A outcomes.
• To compare embryo aneuploidy and pregnancy rates between density gradient (DG) and MFSS sperm selection methods.

Main Methods:

• Couples with prior ICSI/PGT-A failure due to aneuploidy were studied.
• Semen specimens were assessed for total SCF and double-stranded DNA (dsDNA) fragmentation using TUNEL and Comet assays.
• Sperm selection was performed using both density gradient (DG) and microfluidic sperm selection (MFSS) in sequential cycles.
• Embryo aneuploidy, implantation, pregnancy, and delivery rates were compared between DG and MFSS cycles.

Main Results:

• MFSS significantly reduced total SCF from 18.0% to 1.9% and dsDNA fragmentation from 3.1% to 0.3% compared to DG.
• Embryo euploidy rates improved from 25.3% (DG) to 42.9% (MFSS).
• Implantation rates increased from 6.7% (DG) to 65.5% (MFSS), with clinical pregnancy rates rising from 10.5% to 64.6%.

Conclusions:

• High embryo aneuploidy in infertile couples may indicate a subtle male factor related to sperm DNA fragmentation.
• Assessing and addressing SCF is crucial for improving chromosomal integrity and IVF success.
• MFSS enhances the selection of spermatozoa with intact genomes, leading to euploid embryos and increased successful pregnancies.