CRYOPRESERVATION OF SINGLE-DONOR PLATELETS WITH A REDUCED DIMETHYL-SULFOXIDE CONCENTRATION BY THE ADDITION OF 2ND-MESSENGER EFFECTORS - ENHANCED RETENTION OF IN-VITRO FUNCTIONAL-ACTIVITY

BACKGROUND: The potential for bacterial contamination limits the stora ge of platelets at 22 degrees C to 5 days. This creates an inventory p roblem, which could be overcome by the use of cryopreservation to allo w long-term storage of platelets. It has been demonstrated that the ad dition to platelets of a mixture of second-messenger effectors (platel et storage solution), allows these cells to retain significant in vitr o functional activity following cold storage. Analysis is needed of th e ability of this second messenger effector mixture both to protect pl atelets during cryopreservation and to reduce the need for a cryoprote ctant. STUDY DESIGN AND METHODS: Fresh single-donor platelet units (n = 8) were divided into three samples and treated with 8-percent dimeth yl sulfoxide (DMSO), 2-percent DMSO or the platelet storage solution a nd 2-percent DMSO. The samples were placed directly into a -80 degrees C freezer and stored for 1 week, after which they were thawed and ana lyzed for in vitro functional activity. RESULTS: Platelets cryopreserv ed with the platelet storage solution and 2-percent DMSO displayed sta tistically higher retention of functional activity and viability-inclu ding cell number, percent of discoid cells, extent of shape change, an d hypotonic shock response-than did platelets stored by the method usi ng 8-percent DMSO. In addition, the treated platelets displayed statis tically lower expression of p-selectin. The treated platelets showed n o loss of cell number, >88-percent retention of discoid morphology, an d >75-percent retention of ristocetin-induced aggregation as compared to values for these measures in fresh platelets. CONCLUSION: The use o f this platelet storage solution in the cryopreservation of platelets yields a significant improvement in their postthaw in vitro recovery a nd allows for a reduction of the DMSO concentration from 6 to 2 percen t, with superior maintenance of in vitro viability and function.