Cytokines and embryo implantation.

The implantation process is currently considered the most relevant limiting factor for successful pregnancy. It is evident that molecular interactions at the embryo-maternal interface at the time of implantation are crucial in order to understand the mechanisms of embryonic implantation. The principal aim of this study is to demonstrate the existence of specific communication pathways between the human embryo and endometrium. The molecular interactions appears to be initiated by the endometrium in the presence of an implanting blastocyst and is mediated through embryonic cytokines (specifically the IL-1 system) and the target is the endometrial epithelial beta3 integrin subunit. If the role of beta3 is accepted as a marker of uterine receptivity these results may indicate that the normal hormonally regulated human endometrium could be the trigger for molecular events preparing the blastocyst to communicate effectively and regulate endometrial adhesion molecules in order to implant.