Hypothermic preconditioning of endothelial cells attenuates cold-induced injury by a ferritin-dependent process.
Hypothermia for myocardial protection or storage of vascular grafts may damage the endothelium and impair vascular function upon reperfusion/rewarming. Catalytic iron pools and oxidative stress are important mediators of cold-induced endothelial injury. Because endothelial cells are highly adaptive, we hypothesized that hypothermic preconditioning (HPC) protects cells at 0 degrees C by a heme oxygenase-1 (HO-1) and ferritin-dependent mechanism. Storage of human coronary artery endothelial cells at 0 degrees C caused the release of lactate dehydrogenase, increases in bleomycin-detectible iron (BDI), and increases in the ratio of oxidized/reduced glutathione, signifying oxidative stress. Hypoxia increased injury at 0 degrees C but did not increase BDI or oxidative stress further. HPC at 25 degrees C for 15-72 h attenuated these changes by an amount achievable by pretreating cells with 10-20 microM deferoxamine, an iron chelator, and protected cell viability. Treating cells with hemin chloride at 37 degrees C transiently increased intracellular heme, HO-1, BDI, and ferritin. Elevated heme/iron sensitized cells to 0 degrees C but ferritin was protective. HPC increased iron maximally after 2 h at 25 degrees C and ferritin levels peaked after 15 h. HO-1 was not induced. When HPC-mediated increases in ferritin were blocked by deferoxamine, protection at 0 degrees C was diminished. We conclude that HPC-mediated endothelial protection from hypothermic injury is an iron- and ferritin-dependent process.
Zieger
Michael A J
MA
Methodist Research Institute, Indianapolis, IN 46202, USA. mzieger@clarian.org
Gupta
Mahesh P
MP
D049109:Cell Proliferation / Q000187:drug effects; D002478:Cells, Cultured; D003080:Cold Temperature / Q000009:adverse effects; D003331:Coronary Vessels / Q000473:pathology; D003676:Deferoxamine / Q000494:pharmacology; D042783:Endothelial Cells / Q000473:pathology / Q000502:physiology*; D005293:Ferritins / Q000378:metabolism* / Q000502:physiology; D005978:Glutathione / Q000031:analogs & derivatives / Q000032:analysis; D051547:Heme Oxygenase-1 / Q000378:metabolism; D006801:Humans; D007036:Hypothermia, Induced; D007501:Iron / Q000037:antagonists & inhibitors / Q000502:physiology; D019194:Ischemic Preconditioning; D007770:L-Lactate Dehydrogenase / Q000378:metabolism; D015428:Myocardial Reperfusion Injury / Q000139:chemically induced / Q000201:enzymology / Q000517:prevention & control*; D018384:Oxidative Stress / Q000187:drug effects / Q000502:physiology
D005293:Ferritins; D007501:Iron; D007770:L-Lactate Dehydrogenase; D051547:Heme Oxygenase-1; D005978:Glutathione; D003676:Deferoxamine