Increased release of ATP from endothelial cells during acute inflammation.

The effects of lipopolysaccharide (LPS), a potent inflammatory mediator, on the shear stress stimulated release of adenosine triphosphate (ATP) were investigated on endothelial cells from human umbilical vein in primary culture. Human umbilical vein endothelial cells (HUVEC) in primary cultures were subjected to shear stress using a cone and plate apparatus. ATP released by the cells was measured by luminometry, using a luciferin-luciferase assay. Under conditions of shear stress alone (25dyn/cm2), ATP accumulates into the culture medium and reaches a maximum after 3 to 5 min of stimulation (121.7+/-13.2 pmol/ml). The shear stress-stimulated release of ATP was significantly increased after a 4 h pre-incubation of endothelial cells with 50 microg/ml (314.4+/-26.7 pmol/ml) and 10microg/ml lipopolysaccharide (207.7+/-22.2 pmol/ml). Dexamethasone, an anti-inflammatory glucocorticoid, inhibited the effects of lipopolysaccharide. These results show that non-damaged endothelial cells release ATP under experimental inflammatory conditions and support an early role of extracellular ATP in the inflammatory process.