Human vascular endothelial cells produce tumor necrosis factor-alpha in response to proinflammatory cytokine stimulation

Objective: To determine whether human vascular endothelial cells produce tu mor necrosis factor-alpha (TNF-alpha) after stimulation with proinflammator y cytokines and bacterial lipopolysaccharides (LPS). Design: Prospective, in vitro repeated-measurements analysis of cellular re sponses. Setting: Research laboratory in an academic medical center. Subjects: Human umbilical vein endothelial cells (HUVECs). interventions: HUVECs were incubated with interferon-gamma (IFN-gamma), int erleukin-1 beta (IL-1 beta), and LPS, or their different combinations for 2 to 48 hrs. Measurements and Main Results:INF-alpha was measured by time-resolved immun ofluorometric assay. Unstimulated HUVECs did not produce detectable amounts of TNF-alpha, but IFN-gamma, IL-1 beta, and LPS when added together induce d INF-alpha production of HUVEGs in a time-dependent manner. Immunofluoresc ent staining confirmed that the TNF-alpha. was produced by endothelial cell s. IFN-gamma, IL-1 beta, or LPS alone did not induce TNF-alpha production, whereas IFN-gamma and IL-1 beta in combination were able to induce TNF-alph a production to some extent, and the production could be further increased with LPS. TNF-alpha messenger RNA expression was detected with reverse tran scriptase-coupled polymerase chain reaction in stimulated, but not in unsti mulated, HUVEGs. Conclusions: HUVECs are capable of producing TNF-alpha after proinflammator y cytokine stimulation and may therefore contribute to the increased amount of TNF-alpha found in pathologic states such as septic shock.