Monitoring the release of glycocalicin in platelet concentrates by ELISA

Platelet membrane glycoprotein Ib (GPIb) is one of many GPs on the platelet membrane which contribute to the functional and morphological properties of platelets. A principal function of GPIb is its attachment to von Willebrand Factor (vWF) on injured blood vessels which leads to the adhesion of platelets to these vessels. The binding site to vWF resides on glycocalicin (GC), which is a major segment of GPIb. Glycoprotein Ib is particularly susceptible to centrifugation and storage of platelets. The assessment of GPIb status on platelets, therefore, comprises one of many traditional methods for monitoring the quality of platelets during storage. We have recently developed a novel ELISA to monitor GC levels in the supernatant of platelet concentrates (PCs) during storage. Using this ELISA we observed a progressive rise of GC in PC supernatants during storage. A recent study of citrated PCs with or without EDTA produced similar results, and showed a substantial increase of GC levels in EDTA-treated PCs. The GC ELISA could therefore be used as a novel method to monitor PCs during storage under various conditions.