Journal
DEVELOPMENTAL NEUROSCIENCE
Volume 27, Issue 2-4, Pages 87-92Publisher
KARGER
DOI: 10.1159/000085979
Keywords
hypoxia; tolerance; preconditioning; cerebral ischemia; stroke; hypoxia-inducible factor
Categories
Funding
- NATIONAL INSTITUTE OF NEUROLOGICAL DISORDERS AND STROKE [P50NS044283, R01NS043252, R01NS042774, R01NS028167] Funding Source: NIH RePORTER
- NIMH NIH HHS [MH67039] Funding Source: Medline
- NINDS NIH HHS [NS28167, NS43252, NS44283, NS42774] Funding Source: Medline
Ask authors/readers for more resources
Exposure to moderate hypoxia alone does not cause neuronal death as long as blood pressure and cerebral blood flow are maintained in mammals. In neonatal and adult mammals including rats and mice, carotid occlusion in combination with hypoxia produces neuronal death and brain infarction. However, preexposure to 8% oxygen for 3 h protects the brain and likely other organs of neonatal and adult rats against combined hypoxia-ischemia 24 h later. In this paper, the possible mechanisms of this so-called hypoxia-induced tolerance to ischemia is discussed. One mechanism likely involves hypoxia-inducible factor-1 alpha (HIF-1 alpha). HIF-1 alpha is a transcription factor that - during hypoxia - binds with a second protein (HIF-1 beta) in the nucleus to promoter elements in hypoxia-responsive target genes. This causes upregulation of HIF target genes including VEGF, erythropoietin, iNOS, glucose transporter-1, glycolytic enzymes, and many other genes to protect the brain against ischemia 24 h later. In addition, non-HIF pathways including MTF-1, Egr-1 and others act directly or indirectly on other target genes to also promote hypoxia-induced preconditioning. Hypoxia preconditioning can be mimicked by iron chelators like desferrioxamine and transition metals like cobalt chloride that inhibit prolyl hydroxylases, increase HIF-1 alpha levels in the brain, and produce protection of the brain against combined hypoxia-ischemia 24 h later. This hypoxia preconditioning has potential clinical usefulness in protecting high-risk newborns or to provide protection prior to surgery. Copyright (c) 2005 S. Karger AG, Basel.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available