Adjuvant treatment with neuroserpin increases the therapeutic window for tissue-type plasminogen activator administration in a rat model of embolic stroke.
BACKGROUND
After stroke, the thrombolytic effect of tissue-type plasminogen activator (tPA) in the intravascular space is beneficial, whereas its extravascular effect on ischemic neurons is deleterious. We tested the hypothesis that neuroserpin, a natural inhibitor of tPA, reduces tPA-induced neuronal toxicity and increases its therapeutic window for treatment of embolic stroke.


RESULTS
Rats were subjected to embolic middle cerebral artery occlusion (MCAO). Ischemic brains were treated with neuroserpin in combination with recombinant human tPA (n=7), tPA alone (n=7), or saline (n=9). Neuroserpin (20 micro L of 16 micro mol/L active neuroserpin) was intracisternally injected 3 hours and tPA (10 mg/kg) was intravenously administered 4 hours after ischemia. MRI measurements were performed to study blood brain barrier (BBB) leakage and ischemic lesion volume. Administration of tPA alone 4 hours after ischemia significantly (P<0.05) increased BBB leakage in the ischemic core measured by Gd-DTPA-enhanced MRI compared with rats treated with saline. However, treatment with neuroserpin in combination with tPA significantly (P<0.05) reduced BBB leakage, brain edema, and ischemic lesion volume compared with rats treated with tPA alone, although ischemic lesion volumes were the same in both groups before the treatment. Immunostaining revealed that MCAO resulted in reduction of neuroserpin immunoreactivity in the ipsilateral hemisphere after 2 to 6 hours of ischemia. Zymographic assay showed increased plasminogen activity in areas with BBB leakage in rats treated with tPA.


CONCLUSIONS
Administration of neuroserpin after stroke is neuroprotective, seemingly because it blocks the extravascular effect of tPA, leading to subsequent decrease in stroke volume and widening of the therapeutic window for the thrombolytic effect of tPA.
Zhang
Zhenggang
Z
Department of Neurology, Henry Ford Health Sciences Center, Detroit, Mich, USA.
Zhang
Li
L
Yepes
Manuel
M
Jiang
Quan
Q
Li
Qingjiang
Q
Arniego
Polly
P
Coleman
Timothy A
TA
Lawrence
Daniel A
DA
Chopp
Michael
M
D000277:Adjuvants, Pharmaceutic / Q000627:therapeutic use*; D000818:Animals; D001812:Blood-Brain Barrier; D005343:Fibrinolytic Agents / Q000627:therapeutic use*; D020244:Infarction, Middle Cerebral Artery / Q000378:metabolism / Q000473:pathology / Q000628:therapy; D020766:Intracranial Embolism / Q000188:drug therapy* / Q000378:metabolism / Q000473:pathology; D008279:Magnetic Resonance Imaging; D008297:Male; D009479:Neuropeptides / Q000627:therapeutic use*; D018696:Neuroprotective Agents / Q000627:therapeutic use; D010958:Plasminogen / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D015842:Serine Proteinase Inhibitors / Q000627:therapeutic use*; D015843:Serpins / Q000627:therapeutic use*; D020521:Stroke / Q000188:drug therapy* / Q000378:metabolism / Q000473:pathology; D010959:Tissue Plasminogen Activator / Q000627:therapeutic use*; D000097522:Neuroserpin
D000277:Adjuvants, Pharmaceutic; D005343:Fibrinolytic Agents; D009479:Neuropeptides; D018696:Neuroprotective Agents; D010958:Plasminogen; D015842:Serine Proteinase Inhibitors; D015843:Serpins; D010959:Tissue Plasminogen Activator; D000097522:Neuroserpin