Human Vascular Endothelium Heterogeneity

Abstract

Background and Purpose Hormones, neurotransmitters, and autacoids play a key role in the regulation of vascular tone as a result of their interaction with the endothelium. The aim of this study was to compare selected properties of three human endothelial cell lines isolated from cerebral pial arteries (PEC) and two peripheral vessels, the superficial temporal (SEC) and omental (OEC) arteries. Methods Intracellular free calcium concentration ([Ca 2+ ] i ) and receptor protein expression were measured in characterized primary cultures of human endothelial cells. Results All cell lines labeled positively for factor VIII/von Willebrand factor. Growth rate and constitutive release of endothelin-1, expressed as a function of protein, were both significantly lower in cerebral cells (PEC) than in endothelial cells derived from peripheral vessels. Basal [Ca 2+ ] i measured with the fluorescent calcium indicator fura 2-AM (2 μmol/L) did not differ in either of the three cell lines. Although PEC responded to endothelin-1 (0.1 μmol/L) and vasoactive intestinal peptide (1 μmol/L) by a twofold to threefold increase in [Ca 2+ ] i , OEC were unresponsive to these peptides. Moreover, the calcium response to α-thrombin (10 nmol/L) was greater in cerebral (PEC) than in peripheral (SEC, OEC) endothelial cells, while bradykinin (100 nmol/L) increased [Ca 2+ ] i to a similar level in all three cell types. Conclusions This study demonstrates that endothelial cells from different sites of the vasculature exhibit different growth rates and vary in their response to agonists.