Cryopreservation disturbs stimulus-response coupling in a platelet subpopulation

Cryopreservation of platelet suspensions leads to a severe reduction in the functional responses of these cells. This defect primarily resides in a subpopulation which consists of about half the total platelet mass and shows an increased susceptibility to the cryopreservation procedure. Following freeze-thawing this subpopulation failed to aggregate upon stimulation with collagen despite a normal appearance of membrane glycoproteins. Also the contents of alpha granules was similar to the whole suspension and since changes in alpha and dense granule contents often occur in parallel, the poor aggregability could not be attributed to a defect in secretion granules. In contrast, the generation of phosphatidyl-inositol metabolites, the increase in cytosolic Ca2+ content and the phosphorylation of proteins of mol wt 47,000 and 20,000 seen when normal platelets are activated, were completely absent in the subpopulation. These data reveal a severe defect in stimulus-response coupling mechanisms in about half of the platelets after freeze-thawing. The other half of the suspension endures this treatment relatively unharmed and may be used for transfusion.