APOE-E4 allele as a potential marker for implantation failure: A comparison between fertile women, ART success and RIF patients.

Objective: Apolipoprotein E (APOE) is the most important precursor for the production of steroid hormones and is also involved in regulating the function of steroid hormones, hence playing a significant role in reproductive processes. So, APOE gene expression may be correlated with the implantation process. This study tries to make a better clarification of the correlation between APOE gene polymorphisms and recurrent implantation failure (RIF), where we compared the frequency of APOE polymorphisms in RIF patients, assisted reproductive treatment (ART) success cases and fertile women.

Method: In all, 100 women with successful ART who got pregnant (fetal heart rate positive) in their first or second cycle of in vitro fertilization or intracytoplasmic sperm injection, 100 infertile RIF cases, and 100 normal fertile control cases with at least one live birth were included in present study. Following DNA extraction, genotypes were determined through polymerase chain reaction-restriction fragment length polymorphism method using HhaI restriction enzyme. Finally, statistical analysis was performed by chi-squared (χ) test in SPSS software (P < 0.05).

Results: The RIF group showed significantly higher frequency for E3/E4 genotype (29%) compared with the other two control groups (fertile = 15%, ART success [ART+] = 13%) (P = 0.007). There was also a significantly higher frequency of the E4 allele in the RIF group (14.5%) compared with both of the control groups (fertile = 7.5%, ART+ = 6.5%) (P = 0.018).

Conclusion: APOE4 is correlated with recurrent failure in the process of embryo implantation and, accordingly, it may potentially be considered a possible risk factor to the implantation process. The presence of E4 can be proposed as a predictive indicator in determining the results of assisted reproductive techniques.