Background: Platelet transfusion is challenging in emergency medicine because of short platelet shelf life and stringent storage conditions. Platelet-derived extracellular vesicles (PEV) exhibit platelet-like properties. A plasma generated from expired platelet units rich in procoagulant PEV may be able to combine the benefits of plasma and platelets for resuscitation while increasing shelf life and utilizing an otherwise wasted resource.
Study design and methods: Freeze–thaw cycling of platelet-rich plasma (PRP) followed by centrifugation to remove platelet remnants was utilized to generate platelet-enhanced plasma (PEP). An in vitro model of dilutional coagulopathy was also designed and used to test PEP. Rotational thromboelastometry and calibrated automated thrombography were used to assess clotting and extracellular vesicles (EV) procoagulant activity. Capture arrays were used to specifically measure EV subpopulations of interest (ExoView™, NanoView Biosciences). Captured vesicles were quantified and labeled with Annexin-V-FITC, CD41-PE, and CD63-AF647. Platelet alpha granule content (platelet-derived growth factor AB, soluble P-selectin, vascular endothelial growth factor A, and neutrophil activating peptide 2-chemokine (C-X-C motif) ligand 7) was measured. Commercially available platelet lysates were also characterized.
Results: PEP is highly procoagulant, rich in growth factors, exhibits enhanced thrombin generation, and restores hemostasis within an in vitro model of dilutional coagulopathy. The predominant vesicle population were PEV with 7.0 × 10 9 CD41+PS+ EV/ml compared to 4.7 × 10 7 CD41+PS+ EV/ml in platelet-free plasma (p =.0079). Commercial lysates show impaired but rescuable clotting.
Discussion: PEP is a unique candidate resuscitation fluid containing high PEV concentration with preliminary evidence, indicating a potential for upscaling the approach using platelet concentrates. Commercial lysate manufacturer workflows may be suitable for this, but further optimization and characterization of PEP is required.
|Early online date||4 May 2021|
|Publication status||E-pub ahead of print - 4 May 2021|
Bibliographical noteFunding Information:
The authors would like to thank Callum Watson for useful technical discussions regarding ExoView experiments. We also thank Dr. Robert Purcell for useful comments on the manuscript, NHSBT for use of expired platelet units, and Dr Nikki Curry for kindly providing us fibrinogen concentrate. This study was funded by a Defence and Security Accelerator (DASA) award, an MRC Proximity to Discovery grant, and a BHF PhD studentship for JP. The ExoView platform was funded by an EPSRC Capital award awarded to Dr. Sophie Cox.
© 2021 AABB
- platelet extracellular vesicle
ASJC Scopus subject areas
- Immunology and Allergy