Enhanced retention of in vitro functional activity of platelets from recombinant human thrombopoietin-treated patients following long-term cryopreservation with a platelet-preserving solution (ThromboSol) and 2% DMSO

Chemotherapy-induced thrombocytopenia represents a significant clinical pro blem in the management of patients with malignancy. Recombinant human throm bopoietin (rhTPO) is a potent stimulator of platelet production in vivo. Th e ability to cryopreserve rhTPO-derived platelets would enable the use of a utologous platelets during the period of thrombocytopenia. ThromboSol(TM) i s a platelet-stabilizing formulation consisting of second messenger effecte rs that inhibit specific activation pathways endogenous to platelets. To in vestigate the effect of ThromboSol cryopreservation, platelets from rhTPO-t reated patients (n = 23) and normal donors were treated with ThromboSol and 2% DMSO and cryopreserved for up to 6 months. The platelets were thawed at different intervals and tested for retention of platelet functional activi ty in vitro. Following a short-term storage (1 week), the cryopreserved pla telets from patients treated with rhTPO exhibited significantly higher rete ntion of functional activities including discoid morphology (70% v 57%), ex tent of shape change (19% v 13%) stirring shape change (15% v 11%) and hypo tonic shock response (56% v 25%), as compared to the cryopreserved platelet s from controls. Furthermore, there was no further significant loss of func tional activity following cryopreservation for up to 6 months. These findin gs suggest that cryopreservation of platelets from rhTPO-treated donors may provide a useful novel strategy for autologous or allogeneic donation for subsequent transfusions to manage treatment-related thrombocytopenia.