The role of cell adhesion molecules in recurrent implantation failure

Abstract

The endometrium is one of the most dynamic and fascinating tissues in the human body. Its sole purpose is to enable implantation of an embryo during a relatively short time period ‘the implantation window’ in the menstrual cycle. Blastocyst implantation and successful establishment of pregnancy require delicate interactions between the embryo and the maternal environment. Recurrent implantation failure (RIF) is determined when embryos of good quality fail to implant following several in vitro fertilization (IVF) treatment cycles. Implantation failure is related to either maternal factors or embryonic causes. A multitude of molecular factors have been implicated in this complex process, including endometrial integrins, extracellular matrix molecules and adhesion molecules. Cellular adhesion molecules found on the surface of cells are protein molecules which provide cell-cell and cell-extracellular matrix interaction. Cellular adhesion molecules have been identified in virtually all tissues associated with reproductive physiology. In recent years, it is accepted that implantation begins with the help of all adhesion molecules including epithelium integrins and selectins. Reduced in endometrial expression of avβ3 integrin, L-selectin and E-kadherin alone or together may contribute to recurrent implantation failure and these molecules could account as the potential molecular markers of infertility. Cell adhesion molecules, which have a very extensive role in implantation, need to be investigated in more detail in biological and pathological situations. In this review, we aim to provide an overview of our current understanding of the morphological changes which occur to the plasma membrane of the uterine endothelium, and the molecular mechanisms that control communication between the early embryo and the endometrium during implantation.