Protective effects of statins involving both eNOS and tPA in focal cerebral ischemia.
Previous studies have shown that 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors (statins) protect the brain against ischemic injury by upregulating endothelial nitric oxide synthase (eNOS). Here, we tested the hypothesis that statins provide additional beneficial effects by also upregulating endogenous tissue plasminogen activator (tPA) and enhancing clot lysis in a mouse model of embolic focal ischemia. Heterologous blood clots (0.2 mm) were injected into the distal internal carotid artery to occlude blood flow in the middle cerebral artery territory after long-term (14 days) simvastatin, atorvastatin or vehicle treatment. Ischemic lesion volume, neurologic deficits, as well as residual blood clots were measured at 22 h. Reverse transcription-polymerase chain reaction assessed mRNA levels of eNOS, tPA, and the endogenous plasminogen activator inhibitor PAI-1. Ischemic lesion volumes and neurologic deficits were significantly reduced in wild-type mice by both simvastatin and atorvastatin. Statins increased eNOS and tPA mRNA levels but did not change mRNA levels of PAI-1. In eNOS knockout mice, atorvastatin reduced the volume of ischemic tissue and improved neurologic outcomes after arterial occlusion by blood clot emboli. In contrast, statins did not have protective effects in tPA knockout mice after embolic focal ischemia, but only in a filament model where focal ischemia was achieved via mechanical occlusion. These results suggest that statins protect against stroke by multiple mechanisms involving both eNOS and tPA. The involvement of each pathway may be revealed depending on the choice of experimental stroke model.
Asahi
Minoru
M
Neuroprotection Research Laboratory, Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Charlestown, 02129, USA.
Huang
Zhihong
Z
Thomas
Sunu
S
Yoshimura
Shin-ichi
S
Sumii
Toshihisa
T
Mori
Tatsuro
T
Qiu
Jianhua
J
Amin-Hanjani
Sepideh
S
Huang
Paul L
PL
Liao
James K
JK
Lo
Eng H
EH
Moskowitz
Michael A
MA
D000818:Animals; D000069059:Atorvastatin; D002545:Brain Ischemia / Q000188:drug therapy* / Q000378:metabolism*; D004195:Disease Models, Animal; D006538:Heptanoic Acids / Q000494:pharmacology; D019161:Hydroxymethylglutaryl-CoA Reductase Inhibitors / Q000494:pharmacology*; D020766:Intracranial Embolism / Q000188:drug therapy / Q000378:metabolism; D008297:Male; D051379:Mice; D008815:Mice, Inbred Strains; D018345:Mice, Knockout; D018696:Neuroprotective Agents / Q000494:pharmacology; D019001:Nitric Oxide Synthase / Q000235:genetics / Q000378:metabolism*; D052247:Nitric Oxide Synthase Type II; D052250:Nitric Oxide Synthase Type III; D011758:Pyrroles / Q000494:pharmacology; D019821:Simvastatin / Q000494:pharmacology*; D020521:Stroke / Q000188:drug therapy / Q000378:metabolism; D010959:Tissue Plasminogen Activator / Q000235:genetics / Q000378:metabolism*
D006538:Heptanoic Acids; D019161:Hydroxymethylglutaryl-CoA Reductase Inhibitors; D018696:Neuroprotective Agents; D011758:Pyrroles; D000069059:Atorvastatin; D019821:Simvastatin; D019001:Nitric Oxide Synthase; D052247:Nitric Oxide Synthase Type II; D052250:Nitric Oxide Synthase Type III; C496315:Nos3 protein, mouse; D010959:Tissue Plasminogen Activator
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