Endothelium and thrombomodulin: expression and distribution of thrombomodulin on altered endothelium and neoplastic...

We investigated the expression of thrombomodulin (TM) on endothelium in some pathologic states. We used the cultured endothelial cells treated with interleukin-1 (IL-1) and propagated cells by serial subculture for extended periods of time and assessed cell-surface TM molecules. We also studied the distribution of TM on surgical specimens of chorionic diseases, angiosarcoma and on several established cell lines of human choricarcinoma. Subculture of human umbilical vein endothelial cells (HUVE) up to 2 months (approximately 16 subcultures) decreased the number of cell-surface TM molecules by approximately 20% compared to the primary culture. The number of TM molecules also decreased on HUVE treated by IL-1. The treatment of the cells with IL-1 also induced change of shape. TM was found not only normal syncytiotrophoblast but also on neoplastic syncytiotrophoblast of choriocarcinoma and hydatidiform mole. However, TM was not expressed on the three established cell lines. TM was found on various types of vascular tumors, including angiosarcoma.