Human embryos derived from first polar body nuclear transfer exhibit comparatively abnormal morphokinetics during...

Area of Science:

• Reproductive biology
• Assisted reproductive technologies
• Genetics

Background:

• Polar body genome transfer (PB1NT) offers a potential method to rescue genetic material from oocytes, particularly for patients with embryo fragmentation or advanced maternal age.
• Current PB1NT techniques require further refinement for successful clinical application.

Purpose of the Study:

• To evaluate the efficacy and developmental outcomes of PB1NT in in vitro matured (IVM) oocytes.
• To assess fertilization rates, embryonic morphokinetics, and cleavage patterns following PB1NT and intracytoplasmic sperm injection (ICSI).

Main Methods:

• Eighty-five IVM oocytes were divided into PB1NT (n=54) and control (n=31) groups.
• PB1NT involved oocyte enucleation, first polar body (PB1) genomic transfer, and fusion, followed by ICSI.
• Embryo development was monitored using time-lapse imaging to assess fertilization, kinetics, and cleavage patterns.

Main Results:

• Oocyte survival post-enucleation and fusion was 77.14%, with 92.59% PB fusion rate.
• The PB1NT group exhibited significantly lower normal fertilization rates (56.41%) compared to controls (92%).
• Embryos in the PB1NT group showed increased developmental arrest post-four-cell stage, abnormal cleavage divisions (93.3%), and reduced implantation potential and euploidy rates.

Conclusions:

• PB1NT in IVM oocytes can produce normal zygotes after PB fusion and ICSI.
• However, PB1NT is associated with decreased fertilization efficiency and a higher incidence of abnormal embryonic development, indicating limitations for clinical translation.