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Stroke. 2011 Mar;42(3):776-82. doi: 10.1161/STROKEAHA.110.607200. Epub 2011 Feb 11.

Endothelial nitric oxide synthase mediates endogenous protection against subarachnoid hemorrhage-induced cerebral vasospasm.

Author information

1
Department of Neurological Surgery, Washington University School of Medicine, 660 S Euclid Avenue, St Louis, MO 63110, USA.

Abstract

BACKGROUND AND PURPOSE:

Vasospasm-induced delayed cerebral ischemia remains a major source of morbidity in patients with aneurysmal subarachnoid hemorrhage (SAH). We hypothesized that activating innate neurovascular protective mechanisms by preconditioning (PC) may represent a novel therapeutic approach against SAH-induced vasospasm and neurological deficits and, secondarily, that the neurovascular protection it provides is mediated by endothelial nitric oxide synthase (eNOS).

METHODS:

Wild-type mice were subjected to hypoxic PC or normoxia followed 24 hours later by SAH. Neurological function was analyzed daily; vasospasm was assessed on post-surgery Day 2. Nitric oxide availability, eNOS expression, and eNOS activity were also assessed. In a separate experiment, wild-type and eNOS-null mice were subjected to hypoxic PC or normoxia followed by SAH and assessed for vasospasm and neurological deficits.

RESULTS:

PC nearly completely prevented SAH-induced vasospasm and neurological deficits. It also prevented SAH-induced reduction in nitric oxide availability and increased eNOS activity in mice with and without SAH. PC-induced protection against vasospasm and neurological deficits was lost in wild-type mice treated with the nitric oxide synthase inhibitor N(G)-nitro-l-arginine methyl ester and in eNOS-null mice.

CONCLUSIONS:

Endogenous protective mechanisms against vasospasm exist, are powerful, and can be induced by PC. eNOS-derived nitric oxide is a critical mediator of PC-induced neurovascular protection. These data provide strong "proof-of-principle" evidence that PC represents a promising new strategy to reduce vasospasm and delayed cerebral ischemia after SAH.

PMID:
21317271
PMCID:
PMC3042520
DOI:
10.1161/STROKEAHA.110.607200
[Indexed for MEDLINE]
Free PMC Article

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