Recovery of in vitro functional activity of platelet concentrates stored at 4 degrees C and treated with second-messenger effectors.

BACKGROUND

The potential for bacterial contamination limits the storage of platelets at 22 degrees C to 5 days. Refrigerated storage at 4 degrees C would abrogate this problem but would also result in a rapid loss of in vitro viability and functional activity and in vivo viability. The inhibition of platelets during storage by a combination of specific, reversible, second-messenger effectors has been investigated to allow prolonged storage at 4 degrees C with significant retention of in vitro viability and functional activity.

STUDY DESIGN AND METHODS

The combination of effectors was added directly to platelet concentrates, and this step was followed by storage at 4 degrees C. Control units were incubated at 4 degrees C without the effectors and at 22 degrees C according to standard blood-banking techniques. At 1, 5, and 9 days, the units were tested for recovery of cell number, recovery of in vitro functional activity and viability, and expression of platelet surface markers.

RESULTS

Treated platelets stored at 4 degrees C for 9 days, while spherical in shape, displayed no loss of cell number and had a recovery of viability and functional activity, as compared with control platelets stored at 22 degrees C for 5 days, as follows: ADP and collagen aggregation responses of 250 and 100 percent, respectively; a 70-percent recovery of hypotonic shock response; and a 60-percent recovery of extent of shape change. The treated platelets also expressed an equivalent amount of the surface marker glycoprotein lb and a lower amount of the activation marker alpha-granule membrane protein-140 on the membrane surface.

CONCLUSION

Second-messenger effectors added to platelets significantly maintained in vitro functional activity with storage at 4 degrees C. In vitro analysis demonstrates the potential for extended 4 degrees C storage of platelets with numerical and functional recovery comparable to that achieved with current methods. Refrigerated storage of platelet concentrates has the potential to reduce the risk of bacterial contamination.