Antiplatelet Drug Development for Stroke

Platelet adhesion, activation, and aggregation are key events in hemostasis and thrombosis. At the site of vascular injury, platelet aggregates (stabilized by fibrin) rapidly form hemostatic plugs. These plugs or thrombi cause thromboembolic complications of atherosclerosis, such as stroke. Currently, antiplatelet therapy is successfully used in the treatment of noncardiac ischemic stroke and transient ischemic attack (TIA). The most commonly used antiplatelet drugs worldwide include aspirin, clopidogrel, and dipyridamole. However, these drugs exhibit resistance and side effects in clinical use. Additionally, concomitant use of antiplatelet drugs increases the risk of bleeding when used for long-term prophylaxis. Therefore, further development of safer and more effective antiplatelet drugs is needed.

Fig. 1. Antiplatelet drugs and their mechanisms of action on the platelet. (Kamarova et al., 2022)

Our Services

Ace Therapeutics is a stroke-focused preclinical CRO providing reliable antiplatelet drug development services to help clients develop novel antiplatelet drugs. Our laboratories are equipped with advanced molecular biology, cell culture, and high throughput screening instrumentation, enabling us to conduct cutting-edge research in antiplatelet drug development.

Our antiplatelet drug development services cover the entire drug development process, from target identification to preclinical efficacy evaluation.

Target Identification and Validation

Our team of experts has a deep understanding of the mechanism of action of various antiplatelet drugs for stroke prevention, and is dedicated to exploring the key pathways involved in platelet activation and aggregation, such as the thromboxane A2 pathway, ADP receptor (P2Y12), glycoprotein IIb/IIIa, and prothrombin receptor (PAR-1). In addition, we help clients explore less conventional targets such as glycoprotein VI (GPVI), prostaglandin E receptor subtype 3 (EP3), and platelet endothelial aggregation receptor 1 (PEAR1). We use genome-wide association studies (GWAS) to help clients identify genetic variants associated with stroke and platelet function.

Design and Optimization of Antiplatelet Drugs

Large chemical libraries are screened to identify small molecules that inhibit platelet activation. We use surface plasmon resonance (SPR) and isothermal titration calorimetry (ITC) techniques to identify and characterize binding interactions. In addition, we use molecular docking and kinetic simulations to predict how structural changes affect function and binding. We iteratively modify lead compounds to improve potency, selectivity, and pharmacokinetic properties.

In Vitro Evaluation of Antiplatelet Drugs

• Platelet aggregation assay: Assess the antiplatelet activity of drugs.
• Platelet activation markers: Use flow cytometry to measure the effect of antiplatelet drugs on the expression of platelet activation markers, e.g., P-selectin, fibrinogen.
• Platelet adhesion and extent of spreading assay: Determine the effect of antiplatelet drugs on the ability of platelets to adhere to and spread on immobilized adhesion proteins.
• Platelet integrin αIIbβ3 activation: Measure the effect of antiplatelet drugs on the activation of αIIbβ3 integrin using flow cytometry or ELISA.
• Light transmission aggregometry: Measure the increase in light transmission through platelet-rich plasma samples when platelets aggregate in the presence of antiplatelet drugs.
• Platelet-leukocyte aggregation assay: Measure the effect of antiplatelet drugs on the formation of platelet-leukocyte aggregates.

Evaluation of Antiplatelet Drugs Efficacy in Animal Stroke Models

Our laboratory has access to a wealth of animal models of stroke to evaluate the efficacy of antiplatelet drugs for secondary stroke prevention in different stroke subtypes, such as large artery atherosclerosis and small vessel lacunar infarction. In addition, we can we can evaluate the efficacy of different combinations of antiplatelet drugs or the combined use of antiplatelet drugs and anticoagulants.

• Behavioral analysis: Foot fault test, grip strength test, rotating rod test
• TTC staining of brain slices
• Blood-brain barrier (BBB) permeability analysis
• Biomarker analysis: Measurement of inflammatory cytokines, coagulation factors, and other relevant biomarkers in blood and brain tissue.
• Magnetic resonance imaging (MRI) analysis of cerebral infarct volume

Types of Antiplatelet Drugs We Can Develop

• Cyclooxygenase inhibitors
• Phosphodiesterase inhibitors
• ADP receptor antagonists
• Membrane protein IIb/IIIa (GP IIb/IIIa) receptor antagonists
• Adenosine receptor antagonists
• 5-hydroxytryptamine (5-HT) receptor antagonists

Ace Therapeutics' integrated drug development services cover multiple aspects to ensure the successful discovery and optimization of novel antiplatelet drugs. If you are interested in our services, please do not hesitate to contact us!

1. Kamarova, M., et al. (2022). Antiplatelet use in ischemic stroke. Annals of Pharmacotherapy, 56(10), 1159-1173.