Ren's research indicates that blood transfusions can take place beyond that limited window—up to seven hours—and still have a positive impact. Replacing 20 percent of the blood in a mouse was enough to show a profound reduction in damage to the brain. The average adult holds around one-and-a-half gallons of blood in the body. ...snip... The idea is to change the immune response that happens after stroke," Simpkins said.
Researchers explained that following a stroke, the makeup of a patient's blood changes, causing disruptions in the brain and how the body responds. Neutrophils, a type of white blood cell that helps lead the immune system's response, play a role in increasing the levels of an enzyme called MMP-9, which can lead to blood-brain barrier leakage and degeneration in brain tissue.
Blood replacement therapy removes inflammatory cells and decreases neutrophils and MMP-9 levels following a stroke, the study concluded.
"The immune system doesn't recognize much of what's happening when there's a stroke," Simpkins said. "So the neutrophils go to the brain and try to clean up the damage that happens. But there's too much in the brain and those same neutrophils release MMP-9, which then exacerbates the damage.
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Covid-19 does cause strokes. For every Covid-19 death there may be 2-3 strokes in surviving Covid-19 patients.
