Objective: To examine the regulation of endometrial integrin expression by estrogens and progestins in vitro.
Design: Immunocytochemical study.
Setting: Academic research unit.
Patient(s): Twenty-five regularly cycling women without endometrial pathology, of whom seven had endometriosis.
Intervention(s): Endometrial cells obtained by aspiration curettage were treated with diethylstilbestrol, promegestone, and antiprogestin. Immunocytochemistry was performed with antibodies directed against integrins alpha 1 beta 1, alpha 2 beta 1, alpha 4 beta 1, alpha 5 beta 1, alpha v beta 3, and beta 3 integrin subunit.
Main outcome measure(s): Semiquantitative staining score.
Result(s): Endometrial cells express several integrins in vitro in a consistent and cell specific pattern. Neither differences between treated and untreated cells nor an effect of treatment duration or dosage were observed. Cells from patients with and without endometriosis showed similar patterns.
Conclusion(s): The cellular distribution of integrin expression was similar to that described in vivo. In contrast, a steroid regulated expression could not be detected in vitro. Rather, a derepression by a factor not included in our model could be responsible for the cyclic appearance of some integrins. In endometriosis, no fundamental difference of integrin expression was detected.