Biomedical engineers at Duke University have created an injectable biomaterial that may help the brain recover from damage left behind by an ischemic stroke. In experiments with mice, the material transformed the cavity created by lost brain tissue into a more favorable environment for healing. The treatment recruited the body's own immune cells, encouraged the formation of new blood vessels, supported changes in neural tissue, and improved motor function in the animals.
The findings were published in Cell Biomaterials. The Challenge of Repairing Brain Tissue After Stroke Millions of people experience ischemic strokes each year. These strokes occur when a blood clot blocks blood flow to part of the brain.
Emergency treatments such as clot-dissolving drugs and procedures that physically remove the clot can restore circulation and help save brain tissue that is still viable. However, once brain tissue has died, restoring blood flow cannot replace what has already been lost. Severe strokes can destroy substantial amounts of tissue, leaving a cavity where healthy brain tissue once existed.
After doctors remove the clot, recovery depends largely on rehabilitation. Rehabilitation can help surviving brain circuits adapt, but it does not directly rebuild the damaged region. "Once brain tissue has been lost, restoring blood flow is no longer enough," said Tatiana Segura, the Robert Plonsey Distinguished Professor of Biomedical Engineering at Duke.
"Our goal is to engineer the injured space so that immune, vascular and neural repair processes can begin to work together." Segura and her team sought to create an environment inside the stroke cavity that could support several types of repair at once. They used MAPS, or microporous annealed particle scaffolds. These scaffolds consist of individual hydrogel microparticles that assemble into a porous structure.
The open spaces provide cells with a framework they can enter and use while rebuilding neural tissue. Building on earlier successes with the biomaterial, the researchers wanted to determine whether they could also use the body's immune system to guide and strengthen the repair process. For that part of the strategy, they focused on astrocytes.
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