Leveraging Stored Platelet Bioenergetics to Improve Hemostatic Function Upon Transfusion

PROJECT SUMMARY / ABSTRACT The overarching aim of this proposal is to advance the field of personalized transfusion medicine by identifying optimal supplementation and storage procedures to yield platelet products with maximum hemostatic capacity to improve outcomes in actively bleeding patients. There has been renewed interest in using cold-stored platelets (CS-PLT) for bleeding patients due to their increased hemostatic function as compared to conventional room temperature-stored platelets (RT-PLT). We have identified that there is a metabolic signature associated with CS-PLT hemostatic function under physiologically relevant flow conditions. This signature suggests that CS-PLT use thiol redox switches, an underappreciated area of redox biology, to protect from oxidative stress during storage. Yet these switches may also confer enhanced hemostatic activity. The mechanisms by which thiol redox switches modulate platelet activation, adhesion, aggregation, and procoagulant capacity are not well defined. In addition, this points to the opportunity to alter the redox potential of platelet storage solutions through metabolic supplementation to create a platelet product with improved hemostatic function. Lastly, there is a paucity of data concerning the in vivo hemostatic efficacy of long-term stored CS-PLT with or without metabolic supplementation. Thus, our central hypothesis is that cold storage induces a redox environment that is associated with increased hemostatic function, and that by adjusting the redox potential of RT-PLT to mimic that incurred by cold storage will confer improved hemostatic capacity. To test this, we have proposed three aims: (i) to identify the thiol redox status of CS-PLT compared to RT-PLT and identify those switches that are associated with platelet hemostatic function; (ii) to determine whether metabolic supplementation of stored platelets to increase the redox potential potentiates hemostatic function; (iii) and to demonstrate in vivo hemostatic activity of alternatively stored platelet products in murine models. Our collaborative team and premier transfusion medicine research environment are ideally suited to perform these studies, to include the use of microfluidic models of hemostasis and thrombosis and murine models which assess platelet product safety and efficacy. Moreover, this proposal addresses two significant unmet needs. First, the need to extend availability and/or shelf life of products due to critically low supplies. This is addressed through our assessment of CS-PLT stored up to 21 days and identification of supplementation strategies to improve the metabolic “age” of stored platelets. Second, the need to transfuse patients with products that will be effective in stopping bleeding. We will provide much needed data on in vivo hemostatic efficacy of CS-PLT and determine if metabolic supplementation of platelets can enhance hemostatic function. Findings generated by this proposal will provide detailed mechanistic data on CS-PLT with the aim of both improving platelet inventory management and most importantly, outcomes in actively bleeding patients via personalized transfusion medicine.