Development of an Improved System for Platelet Storage

Survival rates of human platelets cryopreserved using current methods are very low (10%). This is largely due to a lack of knowledge regarding the fundamental cryobiology of this cell type. Because of this limitation, most blood banks maintain platelets in non-frozen solutions. Using this approach, platelets can only be stored for about 5 days and then they are discarded. This situation greatly limits the use of platelet transfusion in clinical practice. In addition, the ability to successfully cryopreserve platelets would allow increased time for disease screening (e.g. HIV, HBV, HCV). We have found with other cell types that the major limiting factor in the cryopreservation process is the approach (rate) used to add and remove the cryoprotectant solutes to cells. Therefore, this Phase I project has 3 technical objectives: (1) Determine human platelet cell volume excursion limits (osmotic tolerance limits), (2) Determine platelet plasma membrane permeability coefficients for water and cryoprotectants and their activation energies and (3) Determine optimal methods for addition and removal of cryoprotectants which prevent cell damage. Using this information, Phase II will focus on development of specific device to facilitate the implementation of optimal platelet cryopreservation in blood banks and for military applications in the field. BENEFITS: Platelet survival should be improved using methods developed in this project. This will provide wider application of human platelet utilization in blood bank and transfusion medicine settings. In addition, the longer storage times provided by this technology will allow for more complete disease screening of platelet preparations.