Amorphous silica nanoparticles aggregate human platelets: potential implications for vascular homeostasis

Area of Science:

• Biomedical Engineering
• Nanotoxicology
• Cardiovascular Research

Background:

• Amorphous silica nanoparticles (SiNP) are increasingly used in medical and industrial applications, raising concerns about human exposure.
• Studies suggest SiNP exposure may lead to cardiovascular inflammation and damage.
• Maintaining a balanced nitric oxide/peroxynitrite ratio ([NO]/[ONOO(-)]) is vital for cardiovascular health and platelet function.

Purpose of the Study:

• To investigate the impact of amorphous SiNP on the [NO]/[ONOO(-)] balance within platelets.
• To determine how SiNP influences platelet aggregation.

Main Methods:

• Transmission electron microscopy to visualize nanoparticle-platelet interactions.
• Electrochemical nanosensors for quantifying NO and ONOO(-) release.
• Light aggregometry, flow cytometry, and phase contrast microscopy to assess platelet aggregation.

Main Results:

• Amorphous SiNP exposure resulted in increased NO release followed by a significant ONOO(-) surge, lowering the [NO]/[ONOO(-)] ratio.
• SiNP induced platelet activation, evidenced by P-selectin and glycoprotein IIb/IIIa expression.
• Platelet aggregation was mediated by adenosine diphosphate and matrix metalloproteinase 2, with effects inversely proportional to SiNP size.

Conclusions:

• Amorphous SiNP exposure critically lowers the platelet [NO]/[ONOO(-)] ratio, promoting platelet aggregation.
• These findings offer novel insights into the pharmacological effects of SiNP on platelets.