Pyrophosphate as a novel anticoagulant for storage of whole blood: A proof-of-concept study

Citrate is the only anticoagulant currently Food and Drug Administration (FDA)-approved for the long-term storage of blood for transfusion. Citrate inhibits phosphofructokinase and may play a pro-inflammatory role, suggesting that there may be an advantage to using alternative anticoagulants. Here, we examine the use of pyrophosphate as an anticoagulant.

Whole blood samples from healthy donors were anticoagulated either with citrate-phosphate-adenine-dextrose (CPDA-1) or our novel anticoagulant mixture pyrophosphate-phosphate-adenine-dextrose (PPDA-1). Samples were assessed for coagulation capacity by thromboelastography immediately after anticoagulation (T0) with and without recalcification, as well as 5 hours after anticoagulation (T1) with recalcification. Complete blood counts were taken at both timepoints. Flow cytometry to evaluate platelet activation as well as blood smears to evaluate cellular morphology were performed at T1.

No clotting was detected in samples anticoagulated with either solution without recalcification. After recalcification, clotting function was restored in both groups. R-Time in recalcified PPDA-1 samples was shorter than in CPDA-1 samples. A reduction in platelet count at T1 compared to T0 was observed in both groups. No significant platelet activation was observed in either group at T1. Blood smear indicated platelet clumping in PPDA-1.

We have shown initial proof of concept that pyrophosphate functions as an anticoagulant at the dose used in this study, though there is an associated loss of platelets over time that may limit its usefulness for blood storage. Further dose optimization of pyrophosphate may limit or reduce the loss of platelets.