Altered miRNA-profile dependent on ART outcome in early pregnancy targets Wnt-pathway.

Main goal of this study is to detect the possible alterations in microRNA (miRNA) expression and the pathway targeted in plasma at the time of embryo transfer and pregnancy testing dependent on the assisted reproductive treatment (ART) outcome after ovarian hyperstimulation for in vitro fertilization. Changes in miRNA expression in plasma of women, who became pregnant (n = 6) vs women who failed implantation (n = 6) following day 5 embryo transfer (ET), were investigated at the day of ET and pregnancy testing (PT). Protein expression to validate the finding was performed with a sample size of n = 20 (10 per group) using enzyme-linked immunosorbent assay. Enriched Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses were performed using DIANA-miRPath, v3.0 software based on predicted targets by DIANA-microT-CDS. 4 miRNAs could be identified as possible biomarkers for implantation success. The 11 miRNAs showing the highest significant alterations were all associated with the regulation of WNT3 and WNT7a. While WNT7a presented with a significant decrease between ET and PT in case of ongoing pregnancy, women with implantation failure showed unaltered concentrations. WNT3 presented with a significant decrease in both groups. However, the loss of WNT3 between ET and PT was significantly higher in patients who became pregnant. Main limitation of this prospective study is its small sample size, defining it as a pilot analysis. To conclude, we could demonstrate a significant change in miRNA profile dependent on the ART outcome affecting Wnt pathway. Our findings indicate a possible prospective use of miRNA as biomarkers for implantation success.