Morphological changes in thrombocytes during blood bank storage. An ultrastructural morphometric study.

Monitoring the storage lesion of platelet concentrates (PC) is commonly done by determining metabolic parameters, release of cytoplasmic markers and granules contents and watching the light microscopical appearance of platelets. Descriptions of ultrastructural changes are rare, and so we ascertained the changes in two important organelles, the alpha- and lysosomal granules and the open canalicular system (OCS), by morphometric analysis. Single donor PC's were prepared with a CS-3000 plus (Baxter) processor and stored under routine conditions. The volume fraction of the granules displayed a decrease to 43% after 8 days of storage, and the OCS fraction increased to 143%. Moreover, changes in the morphology of granules and the development of OCS channels are described, and ballooning and even complete lysis of some platelets could be observed after only three days. Furthermore, the membrane flux in the formation of pseudopodia is discussed. Our results stress the need to establish better preparation and storage conditions for platelet concentrates.