Efficacy and Safety of Platelet Glycoprotein Receptor Blockade in Aged and Comorbid Mice With Acute Experimental Stroke.

Background And Purpose: Despite the medical and socioeconomic effect of ischemic stroke and extensive preclinical research, treatment options for ischemic stroke are limited. We recently identified and characterized essential steps of thrombus formation in stroke and demonstrated that inhibition of the platelet glycoprotein (GP) receptors Ib and VI, but not IIb/IIIa, protects young and healthy mice from ischemic neurodegeneration. Whether these findings translate to the clinic remains unclear. Considering that the typical stroke patient is elderly with comorbidity, we aimed to analyze the efficacy and safety of novel preclinical antithrombotics in adult and comorbid mice with acute experimental stroke.

Methods: We subjected adult, healthy, atherosclerotic (Ldlr(-/-)), diabetic (streptozotocin treated), and hypertensive (RenTgMK) mice to a 60-minute transient middle cerebral artery occlusion. Animals were pretreated with anti-GPVI antibodies or treated 1 hour after stroke induction with anti-GPIb or anti-GPIIb/IIIa antigen-binding fragments, respectively. Isotype treatment served as control. Twenty-four hours after transient middle cerebral artery occlusion, we visually assessed the intracerebral hemorrhage rate and measured infarct volumes (using 2,3,5-triphenyltetrazolium chloride-stained brain slices) and functional outcome (using Bederson and grip-test scores).

Results: GPIb and GPVI inhibition protected the mice from ischemic stroke without increasing bleeding complications. In contrast, GPIIb/IIIa inhibition was not protective but increased the intracerebral hemorrhage rate.

Conclusions: Inhibition of early steps of thrombus formation protects adult and comorbid mice from ischemic stroke. The use of clinically meaningful mouse strains might improve the translation of preclinical stroke research to the clinic.