In vitro Evaluation of the Hemostatic Effectiveness of Non Viable Platelet Preparations: Studies with Frozen-Thawed, Sonicated or Lyophilized Platelets

Objectives: Because of the limited life span of platelets in regular storage systems, we were interested in investigating the effects on hemostasis of nonliving platelet derivatives. Methods: We evaluated the effects of different platelet preparations on primary hemostasis in a well-established perfusion model. Studies were carried out with blood anticoagulated with low molecular weight heparin. Similar amounts of frozen-thawed, sonicated or lyophilized platelets were added to normal blood or to blood which had been experimentally depleted of platelets. Platelet interaction with the subendothelium and fibrin deposition were morphometrically evaluated. Results: Addition of nonviable platelet preparations to thrombocytopenic blood always promoted a statistically significant increase in the deposition of fibrin on the subendothelium, but only lyophilized platelets retained some ability to interact with the subendothelium. Flow cytometry studies demonstrated the presence of GPIb, GPIIIa and P-selectin on lyophilized platelets. Conclusions: Preparations containing nonviable platelets may still retain some hemostatic properties.