Summary: Researchers have identified a potential breakthrough for traumatic brain injuries (TBI) using a freeze-dried blood product called “Thrombosomes.” Originally designed for battlefield hemorrhage, this product has demonstrated a unique ability to stabilize damaged blood vessels in the brain, reducing both immediate bleeding and the dangerous brain swelling (edema) that typically follows days later.
The study suggests that these shelf-stable platelets outperform fresh platelets in protecting the “leaky” vessels associated with TBI, providing a much-needed tool for ambulances and remote clinics.
Key Facts
- Five-Year Shelf Life: Unlike fresh platelets, which expire after only seven days and require refrigeration, Thrombosomes are freeze-dried with a sugar called trehalose and can be stored at room temperature for up to five years.
- Stabilizing the “Leak”: The product contains high levels of a specific protein that activates receptors on blood vessel cells, reinforcing them against the “leakiness” that causes life-threatening cerebral edema.
- Superior to Fresh Platelets: While fresh platelets are used for clotting, they haven’t been effective against TBI. Thrombosomes appear to concentrate potent “factors” that go beyond simple clotting to actively reduce brain inflammation.
- Fast-Track Potential: Because Thrombosomes are already in Phase II clinical trials for bleeding disorders, their safety in humans is established, which could significantly accelerate testing for TBI patients.
Source: UCSF
A freeze-dried blood product that could be stored for years on ambulances or in remote emergency departments is showing promise at treating traumatic brain injuries.
The news comes from a mouse study done by researchers at UC San Francisco. If it pans out in people, it could answer a huge unmet need for therapies that treat these injuries, which are the leading cause of death in people under 44 years old.
In addition to the immediate bleeding, traumatic brain injury (TBI) also causes dangerous brain swelling days later, as blood vessels begin to leak. Even if a person is rushed to the hospital, doctors have few options, aside from surgery, to stop the bleeding or the brain swelling.
“In some cases, surgeons will remove part of the skull to relieve the pressure — but there’s no drug that effectively treats swelling, or cerebral edema, directly,” said Shibani Pati, MD, PhD, director of the UCSF Center for Research Transfusion Medicine and Cell Therapies and senior author of the paper, which published March 17 in Blood. “We were excited to see how readily this product reinforced damaged blood vessels in the brain.”
The product, called “Thrombosomes,” was originally developed to control bleeding in battlefield settings. It is derived from platelets that have been freeze-dried with a sugar called trehalose, which helps preserve some of their beneficial contents. It has a shelf life of up to 5 years — far longer than the 7-day shelf life of fresh platelets from human blood donors.
Fresh platelets, which must be stored in refrigerators, are used to treat hemorrhage and some cancer patients and to prevent bleeding during surgery. But they have not been shown to be effective against TBI.
Scientists have only learned how to preserve platelets in the last 30 years, hoping to address an ongoing global shortage of fresh platelets, but no preserved platelet product has been approved for human use, let alone TBI.
The team tested Thrombosomes on the blood vessel cells in petri dishes and in 3D organoid models of blood vessels. The product made both the cell layers and vessels resilient to damage.
Mice that received the product either an hour or a day after a brain injury had less hemorrhage and their blood vessels were not as leaky. They also had less brain inflammation, which can lead to swelling.
The scientists found that the product contained high amounts of a protein that activates a receptor on blood vessel cells, helping to stabilize them. This may explain how the product makes them less leaky.
So far, that protein is the first of what the researchers say could be a cocktail of beneficial molecules.
“Platelets carry many potent factors that go beyond clotting,” Pati said. “In our mouse model of TBI, we saw hints that this product concentrates these factors, making it more effective than platelets themselves.”
The product is in Phase II clinical trials for bleeding disorders, which means it has already been shown to be safe for people. This could hasten trials that test it for TBI.
Authors: Other UCSF authors are Alpa Trivedi, PhD; Byron Miyazawa; Haoqian Zhang, PhD; Longhui Qiu, PhD; Daniel Potter; Austin Edwards; Lindsay Vivona; Maximillian Lin; Callie Keane; Huimin Geng, PhD; Simon J. Cleary, PhD; Alison Nair, MD; and Mark R. Looney, MD. For all authors, see the paper.
Funding: This work was supported by the Department of Defense (W81XWH‐19‐1‐0462 BA180248). For all funding see the paper.
Key Questions Answered:
A: Your skull is a fixed, hard container. When the brain swells (cerebral edema), there is nowhere for the tissue to go, which can cut off blood flow and cause permanent damage. Currently, the main “treatment” is a craniectomy, literally removing part of the skull. A drug that stops the swelling directly would be a game-changer.
A: It’s about concentration and durability. The freeze-drying process preserves and concentrates beneficial molecules that fresh platelets lose quickly. Plus, the ability to keep them in an ambulance for years means treatment can start the moment a paramedic arrives, rather than waiting until the patient reaches a major trauma center.
A: While this study focused on TBI, the mechanism—stabilizing leaky blood vessels—is highly relevant to hemorrhagic strokes. If the product can reinforce the “blood-brain barrier” elsewhere, its applications could expand to various forms of acute brain trauma.
Editorial Notes:
- This article was edited by a Neuroscience News editor.
- Journal paper reviewed in full.
- Additional context added by our staff.
About this TBI and neurology research news
Author: Levi Gadye
Source: UCSF
Contact: Levi Gadye – UCSF
Image: The image is 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, Byron Y Miyazawa, Haoqian Zhang, Longhui Qiu, Daniel Potter, Austin William Edwards, Lindsay Vivona, Maximillian Lin, Callie Keane, Huimin Geng, Simon J Cleary, Alison Nair, Michael M Fitzpatrick, Mark R. Looney, Shibani Pati. Blood
DOI:10.1182/blood.2025031826
Abstract
A Dried Platelet-Derived Biologic for Blood-Brain Barrier Repair and Hemorrhage Control Following TBI in Mice
Traumatic Brain Injury (TBI) is the leading cause of death in children and adults aged 18-44. Despite its high prevalence and devastating consequences, there are currently few effective therapies that target the acute, life-threatening complications of TBI – particularly cerebral edema and intracranial hemorrhage (ICH).
The blood-brain barrier (BBB) and regulation of vascular stability following injury are emerging as critical therapeutic targets. In this study, we evaluate the therapeutic potential of a first-in-class, freeze-dried platelet-derived biologic (FDPlts) in a murine model of TBI. FDPlt transfusion significantly reduces post-TBI ICH and restores cerebral vascular perfusion.
Additionally, FDPlts attenuate BBB permeability, suppress intravascular leukocytosis, and mitigate neuroinflammation evidenced by decreased microglial activation, astrocyte reactivity, and macrophage infiltration. Transcriptomic profiling of cortical and hippocampal tissues reveals that FDPlts downregulate gene networks associated with inflammation and fibrosis, suggesting a role for FDPlts in the modulation of post-injury repair.
Mechanistically, FDPlts are enriched in Angiopoietin-1, a key bioactive protein that signals through the Tie2 receptor pathway, a central regulator of endothelial stability. Inhibition of Tie2 exacerbates BBB permeability after TBI, an effect attenuated by FDPlt administration; implicating Ang-1 as a key mediator of FDPlts mediated BBB protection in TBI.
The BBB plays a vital role in maintaining cerebral homeostasis, and its breakdown after TBI initiates harmful cascades of edema, inflammation, and neuronal injury.
Our findings demonstrate, for the first time, that a dried, platelet-derived biologic can promote vascular repair and neuroprotection in TBI.
