Endothelial cell apoptosis is accelerated by inorganic iron and heat via an oxygen radical dependent mechanism

Ammini K. Jacob, Richard S. Hotchkiss, Susan L. DeMeester, Masako Hiramatsu, Irene E. Karl, Paul E. Swanson, J. Perren Cobb, Timothy G. Buchman*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

59 Scopus citations


Background. Iron participates in diverse pathologic processes by way of the Fenton reaction, which catalyzes the formation of reactive oxygen species (ROS). To test the hypothesis that this reaction accelerates apoptosis, we used human umbilical vein endothelial cells (HUVECs) as surrogates for the microvasculature in vivo. Methods. HUVECs were loaded with Fe [III](ferric chloride and ferric ammonium citrate] with 8-hydroxyquinoline as carrier and were then challenged with two stimuli of the heat shock response, authentic heat or sodium arsenite. Iron dependence was tested with two chelators, membrane-impermeable deferoxamine and membrane permeable o-phenanthroline. The role of ROS was assessed with superoxide dismutase, catalase, and the reporter compound dichlorofluorescein diacetate. The mechanism of cell death was assessed with three complementary techniques, Annexin V/propidium iodide labeling, the TUNEL stain, and electron microscopy. Results. Iron-loaded HUVECs executed apoptosis after a heat shock stimulus. Iron-catalyzed formation of ROS appeared to be a critical mechanism, because both chelation of iron and enzymatic detoxification of ROS attenuated this apoptosis. Conclusions. Inorganic iron, in concert with chemical and physical inducers of the heat shock response, may trigger apoptosis. The accumulation of iron in injured tissue may thereby predispose to accelerated apoptosis and account, in part, for poor wound healing and organ failure.

Original languageEnglish
Pages (from-to)243-254
Number of pages12
Issue number2
StatePublished - Aug 1997
Externally publishedYes


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