Objective: To determine the existence of a soluble signal, secreted from the human blastocyst embryo, that induces HOXA10 gene expression before cell-cell contact.
Design: To analyze, by semiquantitative reverse transcriptase polymerase chain reaction (RT-PCR), cell-free media that had contained human embryos cultured to the blastocyst stage for a soluble molecule that induces HOXA10 expression in an endometrial epithelial cell line (Ishikawa).
Setting: Assisted reproduction technology program of Yale University, New Haven, Connecticut.
Patient(s): Patients undergoing intracytoplasmic sperm injection (ICSI) or in vitro fertilization (IVF) cycles. Treatment of Ishikawa cells with blastocyst-conditioned media.
Main outcome measure(s): Determination of HOXA10 gene expression.
Result(s): We demonstrate that cell-free media that had contained human embryos cultured to the blastocyst stage contain a soluble molecule that induces HOXA10 expression in an endometrial epithelial cell line (Ishikawa). We found that hCG does not induce HOXA10 in Ishikawa cells.
Conclusion(s): Soluble molecules induce a well-characterized marker of endometrial receptivity in endometrial cells without blastocyst apposition. Additionally, HOXA10 induction can serve as a means of evaluating human embryos cultured for IVF and ET. High quality embryos may induce local endometrial receptivity before trophectoderm-endometrial contact.