Neurological deficits caused by tissue hypoxia in neuroinflammatory disease.

TitleNeurological deficits caused by tissue hypoxia in neuroinflammatory disease.
Publication TypeJournal Article
Year of Publication2013
AuthorsDavies, AL, Desai, RA, Bloomfield, PS, McIntosh, PR, Chapple, KJ, Linington, C, Fairless, R, Diem, R, Kasti, M, Murphy, MP, Smith, KJ
JournalAnn Neurol
Volume74
Issue6
Pagination815-25
Date Published2013 Dec
ISSN1531-8249
KeywordsAmidines, Animals, Benzylamines, Disease Models, Animal, Encephalomyelitis, Autoimmune, Experimental, Enzyme Inhibitors, Hypoxia, Hypoxia-Inducible Factor 1, alpha Subunit, Inflammation, Micronutrients, Organophosphorus Compounds, Oxygen, Rats, Recovery of Function, Severity of Illness Index, Single-Blind Method, Spinal Cord Diseases, Ubiquinone
Abstract

OBJECTIVE: To explore the presence and consequences of tissue hypoxia in experimental autoimmune encephalomyelitis (EAE), an animal model of multiple sclerosis (MS).METHODS: EAE was induced in Dark Agouti rats by immunization with recombinant myelin oligodendrocyte glycoprotein and adjuvant. Tissue hypoxia was assessed in vivo using 2 independent methods: an immunohistochemical probe administered intravenously, and insertion of a physical, oxygen-sensitive probe into the spinal cord. Indirect markers of tissue hypoxia (eg, expression of hypoxia-inducible factor-1α [HIF-1α], vessel diameter, and number of vessels) were also assessed. The effects of brief (1 hour) and continued (7 days) normobaric oxygen treatment on function were evaluated in conjunction with other treatments, namely administration of a mitochondrially targeted antioxidant (MitoQ) and inhibition of inducible nitric oxide synthase (1400W).RESULTS: Observed neurological deficits were quantitatively, temporally, and spatially correlated with spinal white and gray matter hypoxia. The tissue expression of HIF-1α also correlated with loss of function. Spinal microvessels became enlarged during the hypoxic period, and their number increased at relapse. Notably, oxygen administration significantly restored function within 1 hour, with improvement persisting at least 1 week with continuous oxygen treatment. MitoQ and 1400W also caused a small but significant improvement.INTERPRETATION: We present chemical, physical, immunohistochemical, and therapeutic evidence that functional deficits caused by neuroinflammation can arise from tissue hypoxia, consistent with an energy crisis in inflamed central nervous system tissue. The neurological deficit was closely correlated with spinal white and gray matter hypoxia. This realization may indicate new avenues for therapy of neuroinflammatory diseases such as MS.

DOI10.1002/ana.24006
Alternate JournalAnn. Neurol.
Citation Key10.1002/ana.24006
PubMed ID24038279
Grant ListG0800954 / / Medical Research Council / United Kingdom
MC_U105663142 / / Medical Research Council / United Kingdom
/ / Medical Research Council / United Kingdom