Apolipoprotein A1: A potential biomarker in the secretome of euploid and aneuploid human embryos.

Objective: Morphologic assessment of an embryo is a valuable indicator for determining embryo health; however, it does not provide information on the chromosomal status of an embryo. Therefore, this study aimed to investigate the levels of Apolipoprotein A1 secreted by day-5 embryos in the spent media of euploid and aneuploid human embryos.

Methods: This study utilized 131 spent culture media samples from 22 infertile couples who were referred to the fertility clinic of Royan Institute. Following ovulation induction, retrieved oocytes were fertilized by intracytoplasmic sperm injection. For pre-implantation genetic diagnosis, embryos were frozen and thawed on days 2 to 3 and a single blastomere was isolated from each embryo for the assessment of chromosomal abnormalities by fluorescence in situ hybridization. Five days after fertilization, the levels of Apolipoprotein A1 were determined in the spent media of normal embryos, aneuploid embryos (with chromosome abnormalities), and the control group (medium without any embryos) using enzyme-linked immunosorbent assay.

Results: The Apolipoprotein A1 levels in the secretome of euploid cleavage-arrested embryos were significantly lower than those in the control group (p<0.04). However, Apolipoprotein A1 levels increased significantly in groups of euploid blastocysts, aneuploid cleavage-arrested embryos, aneuploid morulae, and aneuploid blastocysts compared to the control group (p<0.04). Furthermore, the Apolipoprotein A1 levels in the spent media of euploid early blastocysts were significantly higher compared to euploid hatching blastocysts and aneuploid blastocysts in the early, mid, and late stages (p<0.03).

Conclusions: This study highlights the significant potential of Apolipoprotein A1 as a developmental bi-omarker to distinguish between euploid and aneuploid embryos.