Endocrine Abstracts

The successful establishment of pregnancy is dependent on appropriate embryo development and uterine receptivity. The latter consists of secretory transformation of the glandular epithelial cells followed by decidualisation of the stromal compartment during the mid to late secretory phase of the menstrual cycle. This phase of the cycle is also characterised by extensive tissue remodelling in the superficial layer of the endometrium in preparation for the invasion and implantation of the proliferating trophoblast cells.

Ovarian steroids are known to play a crucial role in the development of a differentiated endometrium capable of supporting implantation. However, many lines of evidence suggest that other locally produced molecules act in an autocrine/paracrine manner to prepare the endometrium for implantation. The regulation of local events critical for decidualisation and tissue remodelling in normal implantation remain poorly defined. However, a host of molecules have been identified following null mutation of individual genes, which result in implantation failure or normal progression of pregnancy. Others have been implicated in the implantation process following observational studies of temporal and spatial gene expression during the window of implantation. More recent technological advances, such as application of cDNA array and proteomic technologies, will outline valuable clues as to the hierarchy of molecular changes and events that culminate in the preparation of a receptive endometrium.

A better understanding of the mechanisms that govern successful implantation is of clinical relevance, as it will assist in the development of improved strategies to correct for pathologies associated with impaired implantation, early pregnancy development and utero-placental function.