In vitro expression of soluble and cell surface-associated CD44 on endometrial cells from women with and without endometriosis

Background Endometriosis is one of the most common benign gynaecological di seases, and attachment of retrogradely shed viable endometrial cells is con sidered to be important in its development. CD44 is a multifunctional adhes ion molecule that undergoes alternative splicing, giving rise to different isoforms. Methods The expression of cell surface-associated CD44 std, v4, v5, v6 and v10 variants before and after cytokine treatment was investigated in endome trial cultures derived from 10 endometriosis patients and 22 women without the disease using immunocytochemistry. The immunoreactivity of soluble CD44 std, v5 and v6 variants was measured in culture medium using an enzyme imm unoassay kit. Results We report on the presence of soluble CD44 in endometrial culture su pernatants. In particular, circulating CD44 standard form levels were signi ficantly higher than levels of splice variants. We also found that both epi thelial and stromal cells express surface-associated CD44 molecules in a di stinct pattern and that this expression is not modulated by tumour necrosis factor (TNF)-alpha or/and interleukin 1 (IL-1) alpha/beta. Finally, cell s urface-associated as well as soluble CD44 expression was similar in the two groups. Conclusion Our results indicate that endometrial cells can serve as a sourc e of circulating CD44, but a direct role in the pathogenesis of endometrios is is rather improbable.