Human endometrial epithelial cells (EEC) constitutively express more intercellular adhesion molecule (ICAM)-1 than endometrial stromal cells (ESC) in culture.
PROBLEM: Intercellular adhesion molecule-1 (ICAM-1) is thought to play an important role in pathophysiological processes in endometrial tissue. The aim of this study was to quantify and compare the expression of ICAM-1 mRNA and protein in cultured endometrial epithelial cells (EEC) versus endometrial stromal cells (ESC). METHOD OF STUDY: EEC and ESC were isolated from human endometrium and cultured. At confluency, ICAM-1 mRNA was measured by real-time reverse transcriptase-polymerase chain reaction, the membrane-bound form (mICAM-1) by immunocytodensitometry, and the soluble form (sICAM-1) by enzyme-linked immunosorbent assay. RESULTS: At the transcriptional level, we observed a 1.7-fold increase in ICAM-1 expression in EEC versus ESC. mICAM-1 immunostaining in EEC [cell-relative membrane-bound signal-specific optical density (CR-M-SOD): 0.056 +/- 0.05] was stronger (P < 0.05) than in ESC (CR-M-SOD: 0.009 +/- 0.07). EEC were found to secrete more (P < 0.01) sICAM-1 ([sICAM-1] = 15.59 +/- 2.96 ng/mL) than ESC ([sICAM-1] = 5.14 +/- 2.61 ng/mL). CONCLUSIONS: Cultured EEC constitutively express significantly more ICAM-1 mRNA and protein than ESC.