Molecular interactions between embryo and uterus in the adhesion phase of human implantation.

Molecular interactions at the embryo-maternal interface at the time of implantation is an exciting field demanding a wide effort in order to understand the crucial process of embryonic implantation. The objective of the present work is to demonstrate the existence of a specific communication pathway (at the molecular level) between embryo and endometrium in the adhesion phase of human embryonic implantation. This pathway of molecular interactions is apparently initiated by the endometrium in the presence of an implanting blastocyst. It is mediated through the embryonic interleukin 0(IL)-1-alpha + IL-1-beta, and the target is the endometrial epithelial beta-3 integrin subunit. If the relevance of beta-3 is accepted as a marker of uterine receptively, these observations may imply that the normal hormonally-regulated human endometrium is the trigger of molecular events preparing the blastocyst to efficiently communicate and regulate endometrial adhesion molecules in order to implant.