Summary: Researchers have reported a promising treatment for traumatic brain injury (TBI) based on a freeze-dried platelet-derived product called Thrombosomes. Developed initially to control battlefield bleeding, this shelf-stable biologic appears to strengthen damaged blood vessels in the brain, reducing immediate hemorrhage and the delayed swelling (cerebral edema) that often follows TBI.
In controlled laboratory experiments using cell cultures, three-dimensional vessel organoids and a mouse model of TBI, Thrombosomes reduced blood-brain barrier (BBB) permeability, limited bleeding, and lowered markers of inflammation. Because this product can be stored at room temperature for years, it has particular appeal for ambulances, rural hospitals and other settings where access to fresh platelets is limited.
Key Facts
- Five-year shelf life: Thrombosomes are produced by freeze-drying platelets with trehalose, a sugar that preserves key components. Unlike donor fresh platelets, which must be refrigerated and expire in about seven days, Thrombosomes remain stable at room temperature for up to five years.
- Stabilizes leaky vessels: The preparation is enriched in proteins that activate receptors on endothelial cells, reinforcing vessel integrity and reducing the “leakiness” that contributes to cerebral edema.
- Different from fresh platelets: Rather than merely promoting clotting, Thrombosomes concentrate biologically active factors that appear to protect blood vessels and suppress neuroinflammation—effects not previously shown for standard platelet transfusions in TBI.
- Clinical development advantage: Thrombosomes are already in Phase II clinical trials for bleeding disorders, so their safety profile in humans is better understood than for a novel product, which could accelerate translational testing for TBI.
Source: UCSF
Freeze-dried platelet product shows potential to treat traumatic brain injuries
A UCSF research team reports that a dried platelet-derived biologic can reinforce damaged cerebral vessels and reduce both bleeding and later swelling in a mouse model of TBI. The findings address a major clinical gap: there are currently few therapies that directly prevent the vascular leakage and inflammation that drive life-threatening cerebral edema after head injury.
In addition to the immediate danger of intracranial hemorrhage, patients with TBI can develop worsening neurologic injury over hours to days as blood vessels become more permeable and the brain swells inside the fixed volume of the skull. Current medical options are limited; in severe cases, surgeons perform a craniectomy to relieve pressure, but there is no approved drug that directly prevents the vascular leak and subsequent edema.
Thrombosomes were designed as a durable, transportable hemostatic product for trauma care. They are made from human platelets preserved with trehalose and lyophilized into a powder that can be reconstituted when needed. In vitro testing showed that the product protects cultured endothelial cell layers and 3D vessel models from injury. In mice, a single administration given one hour or 24 hours after TBI reduced hemorrhage volume, decreased vessel permeability and lowered neuroinflammatory responses compared with untreated controls.
Molecular analysis revealed that Thrombosomes are enriched in Angiopoietin-1, a protein that signals through the Tie2 receptor on endothelial cells to promote stability. Blocking Tie2 increased vascular leak after injury, while treatment with the dried platelet product countered that effect, supporting Angiopoietin-1 as a likely mediator of the protective action. The investigators emphasize that Angiopoietin-1 may be one key component of a broader mix of beneficial factors carried by platelets.
Because Thrombosomes have already completed early clinical testing for bleeding disorders and progressed into Phase II trials, their safety in humans has been at least partially established. That background could shorten the pathway to clinical studies focused on TBI, particularly for pre-hospital or community settings where rapid, on-site treatment could prevent secondary injury.
Authors: Lead authors and contributors on the UCSF paper include Shibani Pati, MD, PhD; Alpa Trivedi, PhD; Byron Miyazawa; Haoqian Zhang, PhD; Longhui Qiu, PhD; Mark R. Looney, MD; and others listed in the published report.
Funding: This work was supported in part by the U.S. Department of Defense (W81XWH‐19‐1‐0462 BA180248).
Key Questions Answered:
A: The skull is a rigid container. When brain tissue swells, pressure rises and can compress blood vessels, reducing blood flow and causing additional, potentially irreversible injury. Surgical decompression is sometimes used, but a drug that prevents swelling would be transformative.
A: Freeze-drying preserves and concentrates bioactive molecules that fresh platelets rapidly lose. The resulting product is durable at ambient temperatures, enabling earlier treatment at the scene of injury and delivering factors that appear to protect the blood-brain barrier beyond simple clotting.
A: The mechanism—stabilizing leaky cerebral vessels—could be relevant to other forms of brain injury that involve vascular breakdown, including some hemorrhagic strokes. Further research is needed to explore those applications.
Editorial Notes:
- This article was edited by a Neuroscience News editor.
- The journal paper was reviewed in full by staff.
- Additional context and clarification were added by the editorial team.
About this TBI and neurology research news
Author: Levi Gadye
Source: UCSF
Contact: Levi Gadye – UCSF
Image: Image credited to Neuroscience News
Original Research: Closed access. “A Dried Platelet-Derived Biologic for Blood-Brain Barrier Repair and Hemorrhage Control Following TBI in Mice” by Alpa Trivedi et al., Blood. DOI: 10.1182/blood.2025031826
Abstract summary
Traumatic brain injury is a leading cause of death and disability among young adults. Acute complications such as intracranial hemorrhage and cerebral edema remain difficult to treat. The blood-brain barrier and endothelial stability are emerging as key therapeutic targets after injury. In this study, a freeze-dried platelet-derived biologic (FDPlts/Thrombosomes) reduced post-TBI hemorrhage, restored cerebral perfusion, decreased BBB permeability and suppressed neuroinflammation in a murine model. Transcriptomic analyses indicated downregulation of pathways linked to inflammation and fibrosis. Mechanistically, FDPlts were enriched in Angiopoietin-1, which signals through the Tie2 pathway to promote endothelial stability; blocking Tie2 worsened permeability and FDPlts mitigated that effect. These findings provide the first evidence that a dried, platelet-derived product can promote vascular repair and neuroprotection after TBI and support further translational study.