Comparative secretome profile analysis of cultured immortalized human endometrial stromal cells supplemented with implanted versus nonimplanted blastocyst‐conditioned medium: A preliminary analysis.

Aim: Human endometrial stromal cells (HESCs) were previously shown to be capable of discriminating embryos with different qualities. Here we aimed to compare the specific response of the HESC secretome to implanted blastocyst‐conditioned medium (BCM) versus nonimplanted medium and identify cytokine candidates useful for the assessment of blastocyst implantation. Methods: Cleavage embryos were individually cultured in one microdrop of medium for blastocyst formation. The BCM was collected after fresh blastocyst transfer on day 5 and used to supplement HESC culture medium. A high‐throughput antibody array covering 440 cytokines was used to detect the secretory proteins of HESCs supplemented with implanted or nonimplanted BCM. Results: A total of 22 differentially expressed proteins were found out of 440 cytokines in the supernatant of HESCs supplemented with BCM from the implanted group compared to the nonimplanted group, including seven upregulated and 15 downregulated proteins. Gene Ontology enrichment analysis showed that the differentially expressed proteins were mainly involved in cell chemotaxis and motility, and ERK1/2 cascade regulation. Kyoto Encyclopedia of Genes and Genomes analysis suggested that the mitogen‐activated protein kinase and phosphatidylinositol 3 kinase/Akt pathways were mainly involved. Conclusion: HESCs specifically responded to BCM from different quality blastocysts, a finding that can be used to develop a novel approach for blastocyst quality assessment. [ABSTRACT FROM AUTHOR]