Changes in platelet morphology and function during 24 hours of storage

Area of Science:

• Biomaterials Science
• Hematology
• Medical Device Testing

Background:

• Standardized protocols for platelet-rich plasma (PRP) preparation are lacking for in vitro studies.
• Varied protocols may lead to inconsistent results in assessing biomaterial thrombogenicity.
• Platelet aging during preparation and storage can underestimate material thrombogenicity.

Purpose of the Study:

• To investigate the impact of whole blood (WB) and PRP storage times on platelet morphology and function.
• To understand how storage affects platelet reactivity and aggregate formation.
• To highlight the need for standardized protocols in hemocompatibility testing.

Main Methods:

• Collected blood from healthy subjects and examined it immediately, 4, and 24 hours later.
• Assessed platelet function using PFA100 closure times with collagen/epinephrine and collagen/ADP agonists.
• Quantified circulating platelets, analyzed morphology and aggregates (CASY), measured P-selectin (CD62P) expression, and assessed platelet factor 4 (PF4) release.

Main Results:

• Whole blood PFA100 closure times increased significantly with storage, exceeding reference ranges after 24 hours.
• Platelet counts decreased after 4 hours, while mean platelet volume and platelet large cell ratio decreased over time.
• Microscopic analysis revealed increased debris and platelet aggregates with longer storage; CD62P expression and PF4 release increased in resting PRP, while ADP-induced platelet activation decreased.

Conclusions:

• Platelet morphology and function, especially reactivity, change rapidly outside the vascular system.
• Consequent standardization in WB and PRP preparation is essential for reliable in vitro hemocompatibility testing.
• Findings are critical for biomaterial development in cardiovascular applications and defining common testing standards.