Two presentations on stroke at a Society for Neuroscience press conference on Tuesday revealed a possible strategy to mitigate stroke’s effects and a brain mechanism at play.
Ron Frostig, at UC Irvine, described his lab’s research into using sensory and sound stimulation as a protective measure against stroke. As Dr. Frostig explained, 88 percent of strokes are ischemic, caused by a blockage of blood flow usually to the middle cerebral artery, or MCA.
Dr. Frostig and his colleagues began their experiment by stimulating the whisker of a rat for about five minutes. Then, they caused a permanent occlusion, or blockage, to the animal’s MCA. Within two hours of the occlusion, they again stimulated a whisker for less than five minutes.
The stimulation proved completely protective to brain injury in the rat.
Next, Dr. Frostig replaced whisker stimulation with auditory stimulation. This, too, was completely protective. As Dr. Frostig concluded, “sensory-induced activation triggers compensatory self-protective mechanisms.”
Could this research translate to humans? Dr. Frostig pointed out that, with the notable exception of Salvador Dali, most of us don’t have whiskers. But he believes that auditory and sensory stimulation could have a protective effect. Stimulation has to impact the area of the brain affected by the stroke—it’s not always possible to know where that is—and must occur within the two hour window. If done too late, stimulation could be harmful. But if you know when a stroke began, about five minutes of auditory and sensory stimulation could be beneficial while waiting for an ambulance to arrive.
Jaime Grutzendler and his colleagues at Yale University Medical School used confocal microscopy to identify a brain process that clears clots from small blood vessels.
By imaging a tiny vessel in a living mouse brain, Dr. Grutzendler saw a vesicle envelop a clot and expel it through the cell wall. In a young brain, the vessels survive. In an older brain, the vessels often die and surrounding vessels suffer permanent injury. This may be why stroke recovery can be more difficult in older people.
Dr. Grutzendler and his colleagues named the process angiophagy, and found that it begins one to three days post-stroke. He hopes that this finding—and future research into how the mechanisms involved work—could lead to new treatments for blockages in the brain, heart, retina, and other organs.
--Johanna Goldberg
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