P-selectin mRNA is maintained in platelet concentrates stored at 4°C

BACKGROUND: Platelets (PLTs) contain mRNA and synthesize proteins in response to activation. Most guidelines for PLT concentrates (PCs) recommend ambient temperature for storage but the impact of the storage temperature on PLT mRNA content has not yet been investigated. STUDY DESIGN AND METHODS: Ten leukoreduced apheresis PCs were split and stored at 22 and 4°C. P-selectin mRNA, its expression on PLTs, and its soluble form were quantified. In parallel, cellular (cell count, mean PLT volume), metabolic (pH, pO2, pCO2, HCO3, glucose), and functional markers (swirling, hypotonic shock response, aggregation to collagen) were analyzed. Rotation thrombelastography was used to monitor the hemostatic potential of PLTs. All measurements were performed on Days 1 and 5 of storage. RESULTS: After 5 days of storage at 4°C, only 31 ± 27 percent of P-selectin mRNA and 29 ± 41 percent of glyceraldehyde-3-phosphate dehydrogenase mRNA were lost, while minute amounts of the mRNAs were detectable at 22°C. In PCs stored at 4°C the percentage of P-selectin–positive PLTs was significantly higher when compared to PCs stored at 22°C. Soluble P-selectin concentrations did not significantly differ between both storage temperatures. Thrombelastography revealed significantly shorter reaction times in PLTs kept at 4°C. CONCLUSION: Our data indicate that storage at 4°C is accompanied by maintained mRNA levels. PLTs with intact mRNA levels and short reaction times in thrombelastography might be functionally superior to PLTs that are devoid of mRNA and show less augmented P-selectin surface expression. In therapeutic applications, that is, if PLTs are transfused to control acute bleeding, PLTs kept at 4°C may be advantageous.