Effects of various doses of aspirin on platelet activity and endothelial function

Area of Science:

• Cardiovascular Medicine
• Pharmacology
• Internal Medicine

Background:

• Aspirin is widely used for cardiac and cerebrovascular disease prevention.
• The optimal dosage of aspirin for maximizing benefits while minimizing risks remains undetermined.
• Understanding dose-dependent effects on platelet activity and endothelial function is crucial.

Purpose of the Study:

• To evaluate the optimal dose of aspirin in healthy volunteers.
• To assess the impact of varying aspirin doses on platelet activity and endothelial function.
• To determine the relationship between aspirin dosage and P-selectin expression, platelet aggregation, and flow-mediated dilation (FMD).

Main Methods:

• Eleven healthy male volunteers received stepwise increasing doses of aspirin (0, 81, 162, 330, 660 mg/day) every 3 days.
• Platelet activity was measured using P-selectin expression (flow cytometry) and platelet aggregation ratio.
• Endothelial function was assessed by brachial artery flow-mediated dilation (FMD) before and after reactive hyperemia.

Main Results:

• Aspirin significantly and dose-dependently suppressed platelet aggregation and P-selectin expression from 81 to 660 mg.
• Flow-mediated dilation (FMD) showed a trend of increase from 0 to 162 mg aspirin.
• A significant decrease in FMD was observed at the highest dose of 660 mg aspirin.

Conclusions:

• Aspirin effectively suppresses platelet activity and P-selectin expression in a dose-dependent manner.
• Lower doses of aspirin (up to 162 mg) may improve endothelial function.
• Higher doses of aspirin (660 mg) can impair endothelial-mediated arterial dilation, suggesting a potential risk.