INTEGRINS AND REPRODUCTIVE PHYSIOLOGY - EXPRESSION AND MODULATION IN FERTILIZATION, EMBRYOGENSIS, AND IMPLANTATION

Objective: To review the available information regarding the role of i ntegrins in reproductive physiology and to discuss their potential cli nical implications. Design: Studies that specifically relate to the ex pression and modulation of integrins in fertilization, embryogenesis, and implantation were identified through the literature and Medline se arches. Result(s): Integrins are a class of adhesion molecules that pa rticipate in cell-to-cell and cell-to-substratum interactions and are present on essentially all human cells. All mammalian eggs express int egrins at their surface, and the integrin alpha(6) beta(1), serves as a sperm receptor that mediates sperm-egg binding. In addition, certain integrin moieties appear to be regulated within the cycling endometri um. Specifically, the expression of beta(1) integrins in the early pro liferative phase is restricted to the glandular epithelium, whereas st romal cells also express beta(1) integrins in the midsecretory phase. The expression of beta(1) integrins increases at the time of implantat ion and remains elevated in the decidua during early pregnancy. A disr uption of integrin expression is associated with certain types of infe rtility in women. The apical surface of the mural trophectoderm does i ndeed possess functional integrins, and trophoblast interactions with extracellular matrix proteins largely depend on the integrin family of adhesion receptors. Conclusion(s): Integrins play particularly import ant roles in both fertilization and embryogenesis, including the proce ss of implantation. (C) 1997 by American Society for Reproductive Medi cine.