Scientists Discover Route of Alzheimer's Transmission

Alzheimer's disease has long been a major challenge for scientists because it destroys brain cells. The main cause of this damage is a toxic protein called Tau. In healthy brains, this protein is harmless, but it becomes sticky in patients with Alzheimer's. Dr. Mitali Tyagi, a researcher at Washington University, has compared these sticky tangles to glue monsters. These monsters block the internal transport system of the cell, which eventually kills the neuron. When the toxic Tau spreads to other areas, patients suffer from worse memory loss.

Recently, researchers at University of Utah Health have discovered how this harmful protein travels. They focused on a normal brain protein called Arc, which helps neurons communicate with each other. Under normal conditions, Arc travels inside tiny membrane-bound sacs that are known as extracellular vesicles. However, the scientists found that toxic Tau can attach itself to Arc inside these vesicles. As a result, the vesicles carry the disease from sick cells into healthy ones.

To confirm this, the team studied mice that did not have the Arc protein. They observed that the transfer of Tau was almost gone when Arc was absent. However, they also pointed out that Arc performs a helpful role during the early stages. The protein helps sick neurons release excess Tau so that the cells can survive longer. If scientists block Arc, the toxic Tau might build up inside the cells and kill them.

For this reason, they believe that the best solution is to stop the vesicles from entering healthy cells. They have also found similar vesicles containing Arc and Tau in human brain tissue. Dr. Jason Shepherd, a neurobiology professor, has explained that they must conduct more research on humans. Although a treatment is still far away, this study might open new paths to slow down the disease.