Neurological deficits caused by tissue hypoxia in neuroinflammatory disease
Article first published online: 17 OCT 2013
© 2013 American Neurological Association
Annals of Neurology
Volume 74, Issue 6, pages 815–825, December 2013
How to Cite
Davies, A. L., Desai, R. A., Bloomfield, P. S., McIntosh, P. R., Chapple, K. J., Linington, C., Fairless, R., Diem, R., Kasti, M., Murphy, M. P. and Smith, K. J. (2013), Neurological deficits caused by tissue hypoxia in neuroinflammatory disease. Ann Neurol., 74: 815–825. doi: 10.1002/ana.24006
- Issue published online: 21 JAN 2014
- Article first published online: 17 OCT 2013
- Accepted manuscript online: 16 AUG 2013 12:11PM EST
- Manuscript Accepted: 3 AUG 2013
- Manuscript Revised: 29 JUL 2013
- Manuscript Received: 4 APR 2013
- Brain Research Trust
- Medical Research Council (United Kingdom)
- Multiple Sclerosis Society of Great Britain and Northern Ireland
- European Union Sixth Framework Program. Grant Number: LSHM-CT-2005-018637
To explore the presence and consequences of tissue hypoxia in experimental autoimmune encephalomyelitis (EAE), an animal model of multiple sclerosis (MS).
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).
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.
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. Ann Neurol 2013;74:815–825