Effects of Tissue Plasminogen Activator and Annexin A2 Combination Therapy on Long-Term Neurological Outcomes of Rat Focal Embolic Stroke

Abstract

Tissue-type plasminogen activator (tPA) in combination with recombinant annexin A2 (rA2) is known to reduce acute brain damage after focal ischemia. Here, we ask whether tPA-plus-rA2 combination therapy can lead to sustained long-term neurological improvements as well. We compared the effects of intravenous high-dose tPA alone (10 mg/kg) versus a combination of low-dose tPA (5 mg/kg) plus 10 mg/kg rA2 in a model of focal embolic cerebral ischemia in rats. All rats were treated at 3 hours after embolization. Brain tissue and neurological outcomes were assessed at 1 month. Surrogate biomarkers for endogenous neurovascular remodeling in peri-infarct area were analyzed by immunohistochemistry. Compared with high-dose tPA alone, low-dose tPA-plus-rA2 significantly decreased infarction and improved neurological function at 1-month poststroke. In peri-infarct areas, tPA-plus-rA2 combination therapy also significantly augmented microvessel density, vascular endothelial growth factor, and synaptophysin expression. Compared with conventional high-dose tPA alone, combination low-dose tPA plus rA2 therapy may provide a safe and effective way to improve long-term neurological outcomes after stroke.