PATTERNS OF EXPRESSION OF INTEGRIN MOLECULES IN HUMAN ENDOMETRIUM THROUGHOUT THE MENSTRUAL-CYCLE

A heterogeneous group of cells interact with each other and with the surrounding matrix to form the complex structure of human endometrium. Since the integrin superfamily of molecules is involved in the cell - cell and cell - matrix interactions, this study was designed to screen, in situ, the cellular distribution of CDW49a-f molecules in human endometrium throughout the menstrual cycle. The integrin molecules were localized by immunohistochemistry using monoclonal antibodies. Glandular epithelium expressed all integrin molecules. With the exception of CDW49d (alpha-4-beta-1), surface epithelium also expressed all these molecules. Endothelial cells were positive for all integrin molecules except CDW49a (alpha-1-beta-1). Endometrial lymphoid cells were positively immunostained for CDW49a, d and e (alpha-5-beta-1) and were negative for CDW49b (alpha-2-beta-1), CDW49c (alpha-3-beta-1) and CDW49f (alpha-6-beta-1). Regional differences in the expression of integrin molecules were observed. As compared to the functionalis epithelium, basalis epithelium characteristically exhibited higher expression of CDW49a, d and e. Two integrins in endometrium, CDW49a and d exhibited changes related to the menstrual cycle. CDW49a, which was not expressed in glandular epithelial cells in the proliferative phase, was strongly expressed in these cells after ovulation and its expression was diminished in the late secretory phase. This molecule was not expressed in the stromal cells, however, predecidual cells characteristically expressed this molecule in the late secretory phase. CDW49d was only expressed in the glandular epithelial cells in the mid-proliferative to mid-secretory phases. The endometrial pattern of expression of integrins shows the large array of molecules involved in the cell - cell and cell - matrix interactions in human endometrium and demonstrates the existence of specific microenvironments in this tissue. In addition, the menstrual cycle-related changes in the expression of these molecules are probably related to the cyclic fluctuations in the levels of steroid hormones.