Unfortunately the brain has limited capacity for recovery after stroke and other diseases. The brain does not regenerate new connections, blood vessels, or new tissues structures like other organs such as the liver or skin; tissue that dies from stroke in the brain is absorbed leaving a cavity that is devoid of axons and neurons.
To investigate whether healthy tissue surrounding the cavity could be coaxed into healing the injured stroke area a gel was engineered to inject into stroke cavities that thickens to mimic properties of brain tissue to create a scaffolding for new growth. Molecules are infused with the gel that stimulate blood vessel growth and suppress inflammation, as inflammation is known to result in scars which will impede regrowth of functional tissues.
16 weeks after being injected with the gel stroke cavities in model mice were found to contain regenerated brain tissue which included new neural networks, gel was absorbed by the body eventually, leaving behind only new tissue. Animals displayed improved motor behavior, exact mechanisms of this were not clear, new axons could be working or new tissue could be improving performance of surrounding unharmed brain tissue.
This study was designed to explore recovery in acute stroke or the period immediately following, in mice it is 5 days and humans that is two months. Next the team will be conducting further studies to determine if brain tissue can be regenerated in a longer period after stroke injury has occurred. It is estimated that upwards of 6 million people within the USA alone are living with long terms outcomes of stroke, of whom this work may be very beneficial to.
NOTE: Image accompanying this article is a photomicrograph of tissue grown into stroke cavity using the bioengineered stroke healing gel. Blue ovoids in the image are cell nuclei in the tissue. Red tubes are blood vessels growing into the stroke site at the center of the image. Green filaments are axons growing along blood vessels as they enter the gel and infarct area. Image credit: UCLA Health
