Enhancing Transfusable Platelets for Hemorrhage Control Using Liposomal Transfection

Uncontrolled bleeding is a leading cause of death worldwide, and occurs in diverse scenarios, including trauma, childbirth, and surgery. There are many therapeutic strategies for stopping blood loss, including transfusion with platelets, cells that initiate blood clotting, but they are not always effective during the most severe cases of bleeding. A potential strategy to improve the efficacy of platelet transfusions is to manipulate the composition of platelets to enhance their natural blood clotting function. We hypothesize that loading therapeutic molecules into transfusable platelets will allow them to promote faster blood clotting specifically at wound sites, improving outcomes after massive transfusions. Until recently, there have not been any clinically appropriate approaches for loading transfusable platelets with therapeutics. We identified, for the first time, that certain formulations of lipid-based nanoparticles can effectively deliver genetic material and enzymes to platelets. We will develop methods to deliver therapeutic molecules to platelets and create a manufacturing protocol for modifying platelets that can be scaled up for clinical use. We will determine whether the modified platelets have enhanced blood clotting function and whether these strategies can be used to safely improve the effectiveness of transfused platelets. Engineering platelets to have enhanced hemostatic function will improve a clinically used strategy to treat hemorrhage, by augmenting our body's natural mechanism to prevent blood loss. This research will yield more effective platelet products, which could be transported and stored for pre-hospital use, increase the efficacy of transfusions, and decrease the number of blood transfusions and transfusion-related adverse effects.

We will achieve these goals by combining our expertise in genetic engineering, nanomedicine, platelet biochemistry, precision medicine, and transfusion medicine. We will complete the following steps:

Objective I – Deliver and load hemostatic proteins to platelets. We will advance our previous work in delivering clot enhancing enzymes to platelets. Lipid nanoparticles that we have previously optimized will be used for delivery, and subsequent assays will assess stability and hemostatic function of modified platelets.

Objective II – Deliver mRNA for protein expression in platelets. Messenger RNA (mRNA) is the genetic material that is translated to produce proteins and enzymes. Platelets are able to produce proteins from their own mRNA, and we will create a biotechnology that enables platelets to produce proteins from man-made mRNA. Building on our published work delivering mRNA to platelets, we will use lipid nanoparticles and several types of mRNA to engineer platelets to synthesize proteins that help clot blood and seal wounds during hemorrhage.

Objective III – Test the efficacy and safety of modified platelets in animal models of hemorrhage and coagulopathy. Using animal models, we will test the ability of these platelets to safely reduce bleeding without causing thrombosis (unwanted blood clot inside of blood vessels) or other adverse effects. A rat model of severe polytrauma and hemorrhage will be used.

This research directly aligns with the Peer Reviewed Medical Research Program Topic Area: Hemorrhage Control, and three Areas of Encouragement. The proposed research directly aligns with research on novel or engineered blood products that offer physiological, logistical, or cost advantages over current products. It also aligns with development of new and innovative capabilities to stop non-compressible intracavitary hemorrhage and improved technologies to stop junctional and pelvic bleeding in pre-hospital environments, as well as development of innovative damage control resuscitation and damage control surgical capabilities. Modified platelets with enhanced coagulability will be designed to be effective in high-demand situations during peak conflicts by reducing the number of platelet units, other blood products, and pharmaceuticals that are currently required. They will be impactful in Roles 1-3 and expected to enable hemorrhage control in challenging situations, such as intracavitary hemorrhage.

We aim to begin field-testing modified platelets in 2025. To accomplish this, our preliminary results and the results obtained by the proposed work will be used to engage with the US Food and Drug Administration and determine the experiments required to begin using modified platelets for managing severe bleeding during trauma. It is expected that the outcomes will benefit Warfighters, Veterans, military beneficiaries, and the American public. We expect that the biotechnologies developed here will reduce death and disability in Service members and subsequently improve the quality of life for Veterans and their families. It will also be applicable in civilian environments. For example, most civilian platelet transfusions are used as part of cancer treatment, and platelets have the potential in the future to be engineered to have enhanced function in this setting.