Overly Reactivated Star-Shaped Cells Explain the Unpredictability of Alzheimer's Disease

Medical Xpress reports that a study in Nature Neuroscience explored the implications of star-shaped "reactive astrocytes" in the mechanism of Alzheimer's disease. The researchers found the severity of these cells is a key indicator for Alzheimer's onset. They learned that mild reactive astrocytes can naturally reverse astrocytic reactivity, while severe reactive astrocytes can induce irreversible neurodegeneration. "This finding suggests experiences such as traumatic brain injury, viral infection, and post-traumatic stress disorder might be necessary to transform a healthy brain to be vulnerable to Alzheimer's disease via excessive oxidative stress," explained C. Justin Lee at the Institute for Basic Science. "The excessive oxidative stress disables the body's ability to counteract the harmful effects of overproduced oxygen-containing molecules, subsequently transforming mild reactive astrocytes into neurotoxic severe reactive astrocytes." The researchers determined that toxin-responsive astrocytes trigger a cellular restoration mechanism and boost hydrogen peroxide by activating monoamine oxidase B — which plays a critical function in reducing dopamine that impedes the signal transmission to generate smooth, purposeful movement. "This study suggests that an important step to establishing a new treatment strategy for Alzheimer's disease should be by targeting reactive astrocytes that appear to be overly activated in the early stages," said Ryu Hoon at the Korea Institute of Science and Technology.