Freeze-dried rehydrated human blood platelets regulate intracellular pH.


BACKGROUND Long-term storage of platelets (PLTs) in the dry state would greatly improve options for PLT storage. Whether trehalose-loaded freeze-dried and rehydrated PLTs could regulate intracellular pH (pHi) was evaluated. STUDY DESIGN AND METHODS Previously it was shown that human PLTs can be successfully preserved by freeze-drying with trehalose. Trehalose-loaded freeze-dried rehydrated PLTs and fresh control PLTs were labeled with the pH dye BCECF-AM. pHi was measured in resting cells, cells acidified with nigericin, and cells treated with thrombin. The sodium-proton pump was blocked by treatment with 5-(N-methyl-N-isobutyl)amiloride (MIA). RESULTS The pHi of rehydrated PLTs is the same as that of fresh control PLTs, 7.27+/-0.03 (SD; n=5) and 7.27+/-0.02 (n=5), respectively. Nigericin treatment of cells showed that the recovery in pHi was Na+-dependent and followed Michaelis-Menten kinetics. The Vmax values (DeltapH/9 sec) were 0.21+/-0.039 (n=3) and 0.22+/-0.025 (n=3) for rehydrated and control PLTs, respectively. The exchange constants were 17.7+/-2.3 mmol per L (n=3) and 17.0+/-1.9 mmol per L (n=3) for rehydrated and control PLTs, respectively. Treatment of cells with MIA showed that NHE1 remained sensitive to the inhibitor after freeze-drying and rehydration. CONCLUSION The results show that the pHi regulation system is largely preserved during freeze-drying and rehydration of PLTs.

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@article{Tang2006FreezedriedRH, title={Freeze-dried rehydrated human blood platelets regulate intracellular pH.}, author={Minke Tang and Willem Frederik Wolkers and John H. Crowe and Fern Tablin}, journal={Transfusion}, year={2006}, volume={46 6}, pages={1029-37} }