The α₂β₁ and α₃β₁ integrins do not mediate attachment of endometrial cells to peritoneal mesothelium

Objective: To evaluate the possible role of mesothelial α₂β₁ and α₃β₁ integrins in the attachment of endometrial stromal cells (ESCs) and endometrial epithelial cells (EECs). Design: In vitro study. Setting: University medical center. Patient(s): Women of reproductive age (n = 26). Main Outcome Measure(s): Mesothelial cells were grown on collagen IV. Endometrial stromal cells and EECs were plated on mesothelial cells for 1 hour. Before plating, mesothelial cells or endometrial cells were incubated with antibodies to α2, α3, and β1 integrin subunits. The effect of these antibodies on ESC and EEC binding to collagen IV and collagen I was also examined. The expression of collagen I, collagen IV, fibronectin, and laminin by cultured ESCs and EECs was examined. Result(s): The anti-integrin antibodies had no effect on endometrial binding to mesothelium. The β1 integrin antibody decreased binding of ESCs and EECs to the collagen matrices. In culture, ESCs and EECs expressed collagen I, collagen IV, fibronectin, and laminin to varying degrees. Conclusion(s): The initial adhesion of ESCs and EECs to mesothelium is not mediated by β1 integrins. In contrast, ESC and EEC attachment to collagen IV and collagen I, which are present in the submesothelial extracellular matrix, is mediated by β1 integrins.