Objective: Our goal was to identify and quantitate growth factors and cytokines actively secreted by a permanent human endometrial cell line with embryotrophic properties and to determine if cell lines enhancing embryo development secrete common growth factors and/or cytokines.
Design: Culture medium conditioned by this human endometrial cell line was screened for platelet-derived growth factor (PDGF), leukemia inhibitory factor (LIF), interleukin-6 (IL-6), epidermal growth factor (EGF), and transforming growth factor-beta (TGF-beta) by enzyme-linked immunoassay (ELISA). Comparisons were made to the African Green monkey kidney epithelial cell line (Vero), which has been well documented to be embryotrophic.
Setting: This study was conducted in a university-based research laboratory associated with a clinical IVF program.
Results: The monkey Vero cell line and our permanent human endometrial cell line produced several common growth factors and cytokines, such as IL-6, PDGF, and LIF. IL-6 was secreted in substantial amounts by both Vero cells (400 pg/ml per 100,000 cells) and endometrial cells (100 pg/ml). PDGF levels in culture supernatant were measured to be 72 and 35 pg/ml, respectively, for Vero and endometrial cells. LIF could not be assayed in our human cell line by ELISA but its presence was evidenced by immunocytochemistry. EGF and active TGF-beta were not detectable in conditioned medium from either cell line.
Conclusions: The two embryotrophic cell lines analyzed in this investigation synthesized several common growth factors and cytokines. Identification of factors being secreted by cell lines which positively influence embryo development may aid us in understanding the basic growth requirements of the preimplantation embryo.