The effect of cold on platelets. II. Platelet function after short-term storage at cold temperatures.

Citrated platelet-rich plasma (PAP) was kept at cold temperatures or room temperature. After 4 hr or more at these temperatures, the PRPs were warmed 1 hr at 37#{176}C. This prevents the spontaneous aggregation seen in chilled PRP that is stirred immediately after warming. Platelet aggregation in response to connective tissue (CT), epinephrine, and adenosine diphosphate (ADP) was considerably greater in the PRPs originally kept at cold temperatures. In addition, chilling would restore the aggregation of platelets whose function had deteriorated due to prolonged storage at warm temperatures. Neither ADP-induced refractoriness, serotonin uptake, or CT-induced serotonin release was affected by cold. Retention in glass bead columns was greater in platelets that had been chilled than in platelets kept at room temperature or 37#{176}C. Thus, the storage of platelets at cold temperatures leads to changes that improve platelet aggregation but may also increase platelet adhesion, which would account for the decreased in vivo survival of platelets preserved for transfusion at cold temperatures. I N A PREVIOUS STUDY, we indicated that cold temperature induces platelet aggregation.’ This phenomenon is responsible for the clumping that occurs in platelet concentrates prepared in the cold.2 Since clumping decreases their in vivo recovery,3 we concluded that the preparation of platelet concentrates under such conditions is probably detrimental. However, it is not clear what temperature is best for the preservation of platelets for transfusion. Traditionally, platelets prepared for transfusion have been stored at cold temperatures. However, recent studies have indicated that the preservation of platelets at cold temperatures, either as platelet-rich plasma or as concentrates,4” shortens their in vivo survival. Thus, in many institutions, platelet concentrates are stored at room temperature, and this is the recommendation of the American Association of Blood Banks (Manual of Blood Component Preparation, 1969.). In addition, it is not clear what temperature of storage best preserves platelet function. Accordingly, this study was undertaken to determine which temperature of storage is better for preservation of in vitro platelet function, and whether storage at cold temperature causes a change in platelets that might effect their ability to circulate in vivo. Our results indicate that (1) platelet function, as measured by aggregation in response to ADP, connective