A quantitative evaluation of alpha 1, alpha 4, alpha V and beta 3 endometrial integrins of fertile and unexplained infertile women during the menstrual cycle. A flow cytometric appraisal

The expression of integrin molecules alpha 1 beta 1, alpha 4 beta 1 and alp ha V beta 3 within endometrial tissue has been proposed as a marker of uter ine receptivity during the implantation window, The present investigation e xamines by flow cytometric analysis the concentrations of alpha 1, alpha 4, alpha V and beta 3 integrin subunits in endometrial stromal (ESC) and epit helial cells (EEC) in two groups of women throughout the menstrual cycle: n ormal fertile women (n = 27) and women with unexplained infertility (n = 26 ). Integrin concentrations in endometrial cells were calculated in relative fluorescence units against a negative cellular control. The assessment of integrin subunits detected the protein in ESC and EEC from the late prolife rative to the late secretory phase. In both groups of women, the al was the highest integrin expressed in ESC and EEC throughout the menstrual cycle. All women exhibited low concentrations of alpha 4-EEC at the time of the im plantation window. Infertile women expressed lower concentrations of the al pha 4-ESC during the proliferative and early secretory phase while lower co ncentrations of the alpha 1-ESC were seen during the late secretory phase. Interestingly, the infertile women expressed lower concentrations of beta 3 -EEC in the early, mid-secretory and late secretory phases (P < 0.05). Infe rtile women also expressed loa er concentrations of alpha 1-EEC and alpha V -EEC during the late secretory phase (P < 0.05). It can be concluded that t he quantitative determination of beta 3-EEC by flow cytometry confirmed its potential feature as a marker of endometrial receptivity at the time of th e implantation window. In addition, the defective expression of the alpha 1 -ESC found in the late secretory phase might be associated with the poor fe rtility outcome of women with unexplained infertility.