Molecular basis of implantation.

The process of embryonic implantation needs coordinated development and communication between the blastocyst and the maternal endometrium. Considerable advances in the understanding of the cell biology of the human embryo and maternal endometrium have been achieved separately. However, the communication between them, and the reciprocal effects on each other, constitute a complicated and yet unsolved question in reproductive medicine that must be further investigated. A paracrine dialogue between the embryo, endometrium and the corpus luteum is known to occur in other species such as rodents and primates. The aim of this work is to present updated information on the embryonic regulation of endometrial epithelial molecules such as adhesion molecules, anti-adhesion molecules, cytoskeletal proteins, chemokines and leptin during the apposition and adhesion phases of human implantation.