Platelets isolated by albumin gradient retain normal activation pathways

Isolated platelets from samples with low counts produce technical problems. Albumin gradient (AG) has been shown to be useful for this purpose, preserving the aggregating response of these cells. The influence of this method in the enzymatic pathways that regulate the platelet activation is studied. Platelets were isolated by either AG or conventional centrifugation methods and labelled with C-14-arachidonic acid (C-14-AA). Isolated platelets were activated with thrombin (5 U/ml) and lipids were extracted according to Bligh and Dyer. Platelet phospholipids and prostanoids were resolved by TLC. The incorporation of C-14-AA by platelets was similar by both methods (31.7 +/- 18% versus 47.2 +/- 6.9%), as well as the distribution of C-14-AA in the five major platelet phospholipids. Formation of radioactive thromboxane B2, hydroxyheptadecatrienoic acid and hydroxyeicosatetraenoic acid by activated platelets was also similar by both methods. These findings suggest that platelet isolation by albumin gradient preserves the enzymatic pathways responsible for the activation of these cells.