Correlation between platelet thrombus formation on collagen-coated beads and platelet aggregation induced by ADP.

ABSTRACT

BACKGROUND: The thrombus-forming ability is a critical in vitro parameter to assess platelets (PLTs), but flow-based methods using collagen-coated materials generally require multistep, proficiency, and advanced analysis. STUDY DESIGN AND METHODS: Commercially available collagen-coated bead columns were examined to assess thrombus-forming ability of PLTs. The retention rate as an index of thrombus formation was calculated using the PLT count before and after column passage. Thrombi were imaged by anti-CD41 using a fluorescent microscope. PLT aggregation was measured by light-transmitting aggregometry. RESULTS: The retention rate was low when apheresis-collected PLT concentrates (PCs) were suspended in plasma either with or without Ca2+. Reconstitution of PCs with red blood cells (RBCs) increased the retention rate with good reproducibility on repeated-measurements, and therefore, PLT samples were reconstructed with RBCs in subsequent experiments. The retention rate of PCs varied widely in a product-dependent manner, and was correlated with the aggregation rate induced by ADP, but not that by collagen. Using platelet-rich-plasma, antagonists of P2Y1 or P2Y12 receptors for ADP reduced both the retention and aggregation of PLTs. Acetylsalicylic acid reduced retention, although it had no effect on ADP-induced aggregation. Prostaglandin E1 significantly inhibited both retention and aggregation. These anti-PLT reagents resulted in reduced or no thrombus formation on the beads. CONCLUSION: The collagen-coated bead column was useful to readily examine the thrombus-forming ability of PLTs. Variance of the PLT retention rate was correlated with responsiveness to ADP. Results from anti-PLT reagents revealed that thrombus formation on collagen-coated beads was similar to in vivo thrombus development.