Regulation of inflammatory and angiogenesis mediators in a functional model of decidualized endometrial stromal cells

The mechanisms involving the expression of interleukin (IL) 1 family members in the process of preparing the endometrium to receive an embryo remain unclear. In this study, decidualization differentially skewed the balance of IL1 family receptor expression in a pattern that increases endometrial stromal cell receptivity to IL1, IL18 and IL33. Additionally, endometrial cells showed increased expression of homeobox HOXA10 and HOXA11 and LIFR, which are known to be involved in endometrial embryo receptivity. Further analyses of decidual endometrial cells revealed a significant increase in the release of potent proinflammatory, remodelling and angiogenic factors implicated in the embryo invasion process, such as VEGF (P = 0.0305), MMP9 (P = 0.0003), TIMP3 (P = 0.0001), RANTES (P = 0.0020), MCP1 (P = 0.0001) and MIF (P = 0.0068). No significant changes in endogenous IL1B secretion were observed. Decreased secretion of IL18 and decidualization increased secretion of IL33. These findings reveal a significant modulation of endometrial cell receptivity to IL1 family members during endometrial stromal cell decidualization, and suggest that the involvement of IL1 family members is important in physiological processes of endometrial receptivity, including adaptive immunology. This may be relevant to establishing a favourable uterine microenvironment for embryo implantation.