Dried Platelet Biologic Reduces Hemorrhage After Traumatic Brain Injury

Traumatic brain injury (TBI) triggers immediate intracranial bleeding and days-later cerebral edema that can rapidly worsen neurological injury. Effective drug options to curb these processes are limited, leaving surgery as the main recourse when pressure rises. The clinical burden is substantial because TBI is a leading cause of death in people under 44 years of age. To help address this challenge, researchers have developed a shelf-stable, platelet-derived biologic intended to reduce vascular leak and hemorrhage after TBI.

Investigators at the University of California, San Francisco (UCSF) evaluated a freeze-dried platelet product called thrombosomes, originally created to control bleeding in battlefield settings. The formulation is produced by drying platelets with trehalose, preserving key bioactive components and providing a shelf life of up to five years, compared with seven days for donor platelets. Fresh platelets are widely used for hemorrhage control and perioperative support, but they have not been shown to be effective in TBI. No preserved platelet product has been approved for human use.

Mechanistically, analysis of thrombosomes revealed high levels of a protein that activates a receptor on vascular endothelial cells. This interaction stabilized the blood–brain barrier and reduced leakiness in vitro. The team demonstrated these effects in endothelial cell monolayers and in three-dimensional organoid models of blood vessels.

In vivo validation in mice showed that dosing one hour or one day after experimental brain injury reduced intracranial hemorrhage and vascular permeability. The treatment also lessened neuroinflammation, a contributor to delayed cerebral edema. The findings are reported in Blood. The product is already in Phase II clinical trials for bleeding disorders, indicating prior demonstration of human safety, and this could accelerate clinical testing for TBI.

“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, Ph.D., director of the UCSF Center for Research Transfusion Medicine and Cell Therapies and senior author of the paper. "We were excited to see how readily this product reinforced damaged blood vessels in the brain."

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UCSF Center for Research Transfusion Medicine and Cell Therapies