Integrin cell adhesion molecules in endometrium of fertile and infertile women throughout menstrual cycle

323-331Integrins (ITGs) are ubiquitous cell adhesion molecules that undergo dynamic alterations during the normal menstrual cycle in human endometrium. The di stribution of four different subunits, viz. α4, α6, β3 and β4 in human endometrial tissue at different stages of the menstrual cycle was studied using immunohistochemical, enzyme immunoassay and SDS-PAGE/ Western blot techniques. The specificity of each mAb to their respective ligands viz. , laminin (Ln), fibronectin (Fn) and vitronectin (Vn) was done by cell adhesion assays. Both α6 and β4 subunits (Ln receptors) expressed primarily on the glandular epithelium, while glandular, stromal and luminal cells expressed predominantly α4 (Fn receptor) and β3 (Vn receptor). The appearance of α4 and β3 ITG subunits was found to be cell and cycle specific. The levels of both α6 and β4 increased throughout the menstrual cycle, while β3 subunit appeared abruptly on cycle day 19/20. The immunostaining for α4 and β3 was absent in 90% of infertile women. The timing of expression of α4 and β3, the two cycle - dependent ITGs framed the putative window of implantation and suggests a role in the diagnosis of infertility. In conclusion, the absence of α4 and β3 ITG expression in the endometrium of infertility subjects during mid luteal phase may be associated with defects in uterine function. The defective uterine receptivity may be an unrecognised cause of infertility in these group of women