title: Intravenous administration of a GPIIb/IIIa receptor antagonist extends the therapeutic window of intra-arterial tenecteplase-tissue plasminogen activator in a rat stroke model.
abstract: OBJECTIVE
  Occlusion of the middle cerebral artery triggers platelet accumulation at the site of occlusion and in downstream microvessels. The platelet-induced secondary thrombosis promotes the progressive development of ischemic brain damage and contributes to the resistance to thrombolysis and to the tight 3-hour therapeutic window. We tested the hypothesis that combination of intravenous (IV) administration of a GPIIb/IIIa receptor antagonist, 7E3 F(ab')2, with intra-arterial (IA) administration of tenecteplase-tissue plasminogen activator (TNK-tPA) increases the efficacy of thrombolysis and extends the therapeutic window of stroke.
  
  
  METHODS
  Rats subjected to embolic stroke were treated with IV 7E3 F(ab')2 (6 mg/kg) in combination with IA or IV TNK-tPA (5 mg/kg) at 4 and 6 hours after onset of stroke, respectively; IA TNK-tPA (5 mg/kg) alone at 6 hours after onset of stroke; or saline at 6 hours after onset of stroke.
  
  
  RESULTS
  The combination of IV 7E3 F(ab')2 (4 hours) and IA TNK-tPA (6 hours) significantly (P<0.05) reduced infarct volume and improved neurological functional deficits, which was associated with significant (P<0.05) reductions in the size of embolus at the origin of the occluded middle cerebral artery and in down-stream microvascular platelet and fibrin deposition, and enhanced microvascular patency compared with saline-treated rats. However, combination of IV 7E3 F(ab')2 (4 hours) and IV TNK-tPA (6 hours) or IA TNK-tPA (6 hours) alone failed to reduce infarct volume and improve neurological function compared with the saline-treated rats. No significant differences of the incidence of hemorrhage were detected among groups.
  
  
  CONCLUSIONS
  These data suggest that the combination of IV 7E3 F(ab')2 (4 hours) and IA TNK-tPA (6 hours) extends the therapeutic window of thrombolysis to 6 hours after stroke.
authors.affiliation: Neurology Department, Henry Ford Health Sciences Center, Detroit, Mich, USA.
authors.forename: Li
authors.initials: L
authors.lastname: Zhang
authors.forename: Zheng Gang
authors.initials: ZG
authors.lastname: Zhang
authors.forename: Chunling
authors.initials: C
authors.lastname: Zhang
authors.forename: Rui Lan
authors.initials: RL
authors.lastname: Zhang
authors.forename: Michael
authors.initials: M
authors.lastname: Chopp
mesh_terms: D000818:Animals; D002543:Cerebral Hemorrhage; D004195:Disease Models, Animal; D005343:Fibrinolytic Agents / Q000008:administration & dosage*; D020244:Infarction, Middle Cerebral Artery / Q000188:drug therapy; D007261:Infusions, Intra-Arterial; D007262:Infusions, Intravenous; D008297:Male; D010975:Platelet Aggregation Inhibitors / Q000008:administration & dosage*; D019039:Platelet Glycoprotein GPIIb-IIIa Complex / Q000037:antagonists & inhibitors*; D051381:Rats; D017208:Rats, Wistar; D020521:Stroke / Q000188:drug therapy*; D000077785:Tenecteplase; D015912:Thrombolytic Therapy; D013997:Time Factors; D010959:Tissue Plasminogen Activator / Q000008:administration & dosage*
chemical_list: D005343:Fibrinolytic Agents; D010975:Platelet Aggregation Inhibitors; D019039:Platelet Glycoprotein GPIIb-IIIa Complex; D010959:Tissue Plasminogen Activator; D000077785:Tenecteplase