Adjuvant treatment with a glycoprotein IIb/IIIa receptor inhibitor increases the therapeutic window for low-dose tissue plasminogen activator administration in a rat model of embolic stroke.
BACKGROUND
Platelet aggregation and fibrin deposition are key events leading to microvascular thrombosis and progressive impairment of downstream microvascular perfusion after stroke. We tested the hypothesis that inhibition of platelet function with a GP IIb/IIIa receptor antagonist would increase the efficacy and safety and increase the time window for thrombolytic therapy for stroke with full- and half-dose tissue plasminogen activator (tPA).


RESULTS
Rats were subjected to embolic middle cerebral artery occlusion. Four hours after ischemia, rats were treated with 7E3 F(ab')2 (6 mg/kg) in combination with tPA at doses of 10 and 5 mg/kg, tPA alone at a dose of 10 or 5 mg/kg, 7E3 F(ab')2 (6 mg/kg) alone, or saline. Combination treatment with 7E3 F(ab')2 and tPA (full- or half-dose) significantly (P<0.05) reduced infarct volume and neurological deficits compared with saline-treated rats. However, treatment with 7E3 F(ab')2 or tPA (full- or half-dose) alone did not reduce infarct volume. Quantitative measurements of cerebral microvessels perfused by FITC-dextran revealed that combination treatment with 7E3 F(ab')2 and full-dose tPA significantly (P<0.05) increased the percentage of FITC-dextran-perfused vessels compared with saline and full-dose tPA-treated rats. In addition, treatment with 7E3 F(ab')2 in combination with full-dose tPA significantly (P<0.05) decreased microvascular platelet accumulation and matrix metalloproteinase 9 immunoreactivity and protected against loss of collagen IV immunoreactivity.


CONCLUSIONS
Combination treatment with 7E3 F(ab')2 with full- and half-dose tPA at 4 hours after ischemia significantly reduces infarct volume and improves neurological outcome. Enhancement of patency and integrity of cerebral microvessels most likely contributes to the benefits observed with this combination therapy.
Zhang
Li
L
Department of Neurology, Henry Ford Health Sciences Center, Detroit, Mich, USA.
Zhang
Zheng Gang
ZG
Zhang
Ruilan
R
Morris
Daniel
D
Lu
Mei
M
Coller
Barry S
BS
Chopp
Michael
M
D000077284:Abciximab; D000818:Animals; D000911:Antibodies, Monoclonal / Q000627:therapeutic use*; D001835:Body Weight / Q000187:drug effects; D002560:Cerebrovascular Circulation / Q000187:drug effects; D017024:Chemotherapy, Adjuvant; D004195:Disease Models, Animal; D004305:Dose-Response Relationship, Drug; D004357:Drug Synergism; D005342:Fibrinolysis / Q000187:drug effects; D007140:Immunoglobulin Fab Fragments / Q000627:therapeutic use*; D020244:Infarction, Middle Cerebral Artery / Q000150:complications / Q000188:drug therapy; D007262:Infusions, Intravenous; D007275:Injections, Intravenous; D020766:Intracranial Embolism / Q000150:complications / Q000188:drug therapy*; D008297:Male; D008833:Microcirculation / Q000187:drug effects; D019039:Platelet Glycoprotein GPIIb-IIIa Complex / Q000037:antagonists & inhibitors*; D051381:Rats; D017208:Rats, Wistar; D020127:Recovery of Function / Q000187:drug effects; D020521:Stroke / Q000150:complications / Q000188:drug therapy*; D010959:Tissue Plasminogen Activator / Q000008:administration & dosage*; D016896:Treatment Outcome
D000911:Antibodies, Monoclonal; D007140:Immunoglobulin Fab Fragments; D019039:Platelet Glycoprotein GPIIb-IIIa Complex; D010959:Tissue Plasminogen Activator; D000077284:Abciximab