The storage lesion of platelets: ultrastructural and functional aspects

When prepared and stored as concentrates, platelets undergo a lot of structural, biochemical and functional alterations that lead to an impaired function after transfusion. Besides signs of activation like disc-to-sphere transformation, extension of pseudopodes and loss of storage granules, platelets may display a swollen open canalicular system and changes in the structure of their alpha-granules. These partly reversible morphological alterations correspond to a deterioration of basic metabolic parameters and a decrease in the reactivity of stored platelets to weak agonists. All these changes occur to a very different degree depending on the methods of preparation and storage. With the introduction of acetate-containing additive solutions, the storage conditions could be greatly improved, and platelets from pooled buffy coats and stored in an acetate-containing medium with at least 20% autologous plasma show the best structural integrity over 8 days of storage.