CULTURING OF HUMAN VASCULAR ENDOTHELIAL-CELLS STRONGLY AFFECTS THEIR ENDOTHELIN-1 AND PROSTACYCLIN PRODUCTION

Cultured human umbilical vein endothelial cells (HUVECs) are a widely used model to study the regulation of endothelial production of vasoac tive substances such as endothelin-1 (ET-1) and prostacyclin (PGI(2)) in human. As even short term culturing is known to affect the function of many cell types, we studied whether there are differences in the p roduction of ET-1 and PGI(2) between freshly isolated HUVECs and HUVEC s cultured for two passages, and whether variation in cell density aff ects the production of ET-1 and PGI(2) by these cells. At confluency, freshly isolated HUVECs produced only from one-tenth to one-fifth of E T-1, but 46-86 times more PGI2 (p < 0.001), when compared to respectiv e productions by similar amounts of cultured HUVECs. When the cell den sity of freshly isolated HUVECs was lowered either by diluting the cel l suspension or by plating the same amount of cells on different size wells, the production of ET-1 increased: lowering cell density to one- tenth led to 18 fold increase in ET-1 production (p < 0.001). PGI(2) p roduction was not affected by cell density. Thus our data imply that; the production of both ET-1 and PGI(2) are differently regulated in fr eshly isolated and cultured HUVECs, and that cell density is an import ant determinant in the regulation of ET-1 production.