PB0343 - N-Acetyl Cysteine Prevents Occlusive Arterial Thrombosis in a Dose-Dependent Manner

Background: Platelet-rich thrombi formed with elongated VWF can cause occlusions of arteries causing fatal infarcts. N-acetyl cysteine (NAC) has been shown to cleave vWF and promote clot lysis previously. In this study we investigate the efficacy of NAC to prevent thrombi from forming under high shear stress conditions.

Aims: Prevention of arterial thrombosis due to NAC is assessed. A dose-response curve for occlusion time in NAC-treated human blood is assessed in a microfluidic assay. Efficacy is shown in a murine model.

Methods: Human whole blood incubated with 3, 5 or 10mM NAC for 30 minutes was run through a microfluidic device of a stenosis. Occlusion time (OT) and platelet intensity were measured. Subsequently, a Modified-Folts model of a carotid stenosis in 13 mice were treated with either 200, 400 mg/kg NAC or vehicle 45 minutes prior to the carotid injury.

Results: Human blood treated with 3mM or 5mM NAC had occlusion times of 255s and 457s respectively while the control OT was 124s (Figure 1). Blood treated with 10mM NAC did not occlude and no platelet aggregation was detected during the experiment. Platelet intensity measurements show the increase in occlusion time is due to a decreased platelet aggregation rate. Mice treated with 200mg/kg NAC formed occlusive thrombi in 18.0m versus 9.4m for the control (Figure 2). 80% of the control clots were stable and remained occlusive, while all 200mg/kg clots were unstable, breaking and reforming. No clots were formed in the 400mg/kg mice.

Conclusion(s): NAC reduces the rate of platelet aggregation and increases the time to form occlusion with concentrations between 3 mM and 10mM. At 10mM NAC completely prevented platelet aggregation. This work demonstrates the dose-response curve for NAC preventing arterial thrombosis with human and murine blood, and provides evidence that NAC can be repurposed into an anti-thrombotic therapeutic.