COU254, a specific 3-carboxamide-coumarin inhibitor of coagulation factor XII, does not protect mice from acute ischemic stroke

Abstract

BackgroundAnticoagulation is an important means to prevent from acute ischemic stroke but is associated with a significant risk of severe hemorrhages. Previous studies have shown that blood coagulation factor XII (FXII)-deficient mice are protected from pathological thrombus formation during cerebral ischemia without bearing an increased bleeding tendency. Hence, pharmacological blockade of FXII might be a promising and safe approach to prevent acute ischemic stroke and possibly other thromboembolic disorders but pharmacological inhibitors selective over FXII are still lacking. In the present study we investigated the efficacy of COU254, a novel nonpeptidic 3-carboxamide-coumarin that selectively blocks FXII activity, on stroke development and post stroke functional outcome in mice.MethodsC57Bl/6 mice were treated with COU254 (40 mg/kg i.p.) or vehicle and subjected to 60 min transient middle cerebral artery occlusion (tMCAO) using the intraluminal filament method. After 24 h infarct volumes were determined from 2,3,5-Triphenyltetrazoliumchloride(TTC)-stained brain sections and functional scores were assessed. Hematoxylin and eosin (H&E) staining was used to estimate the extent of neuronal cell damage. Thrombus formation within the infarcted brain areas was analyzed by immunoblot.ResultsInfarct volumes and functional outcomes on day 1 after tMCAO did not significantly differ between COU254 pre-treated mice or untreated controls (p > 0.05). Histology revealed extensive ischemic neuronal damage regularly including the cortex and the basal ganglia in both groups. COU254 treatment did not prevent intracerebral fibrin(ogen) formation.ConclusionsCOU254 at the given concentration of 40 mg/kg failed to demonstrate efficacy in acute ischemic stroke in this preliminary study. Further preclinical evaluation of 3-carboxamide-coumarins is needed before the antithrombotic potential of this novel class of FXII inhibitors can be finally judged.

Factor XIIa inhibition by Infestin-4: in vitro mode of action and in vivo antithrombotic benefit

“…Few FXIIa small molecule inhibitors have been reported. The 3-carboxamide-coumarins are a recently explored structural class awaiting further evaluation of their potency, selectivity, and pharmacological effects in preclinical models (19,20). Infestin-4 is a Kazal domain-containing, native FXIIa inhibitor originally isolated from the haematophagous insect Triatoma infestans (21).…”

The many faces of the contact pathway and their role in thrombosis

“…Novel 3-carboxamide-coumarin inhibitors were developed to be potent and selective inhibitors of FXIIa [132]; however, COU254 did not protect mice from ischemic stroke in a tMCAO at the given concentration [133]. D-ProPhe-Arg chloromethyl ketone (PCK) inhibits the amidolytic activity of FXIIa, was able to increase clotting time in a dose-dependent manner, and protect mice against ischemic brain stroke in a tMCAO [63].…”

“…Effects of FXI and FXII inhibitors in animal thrombosis models[63,66,67,69,72,73,133,[138][139][140][141] …”

Factor XII/XIIa inhibitors: Their discovery, development, and potential indications

“…Among the most attractive compounds, COU-254 and COU-294 emerged as weak but selective FXIIa inhibitors [195]. Due to its higher solubility, COU-254 was selected for in vivo testing and failed to demonstrate efficacy in acute ischemic stroke [203]. COU-294, the most potent, was selected for further optimization.…”