Mesothelial cell-associated hyaluronic acid promotes adhesion of endometrial cells to mesothelium

OBJECTIVE: To evaluate the role of hyaluronic acid in the attachment of endometrial cells to mesothelium. DESIGN: In vitro study of adhesion of endometrial stromal and epithelial cells to mesothelial cells. SETTING: University medical center. PATIENT(S): Reproductive-age women without endometriosis undergoing surgery for benign conditions. INTERVENTION(S): None. MAIN OUTCOME MEASURE(S): The effect of hyaluronidase treatment of mesothelial cells or endometrial cells on adhesion of (51)Cr labeled endometrial stromal and epithelial cells to monolayers of mesothelium was evaluated. The expression of CD44, the hyaluronate receptor, was evaluated by western blot. RESULT(S): Hyaluronidase pretreatment of mesothelial cells decreased the binding of endometrial stromal and epithelial cells to mesothelium by 39% (P< .02) and 31% (P< .03), respectively. There was no effect on endometrial cell binding to mesothelial cells or to collagen IV when the endometrial cells were pretreated with hyaluronidase. CD44 expression by endometrial stromal and epithelial cells was demonstrated by western blot. CONCLUSIONS: This study demonstrates that mesothelial cell-associated hyaluronic acid is involved in attachment of endometrial stromal and endometrial epithelial cells to the mesothelium. We hypothesize that binding of hyaluronic acid by endometrial cells is involved in the pathogenesis of the early endometriotic lesion.