Alzheimer’s disease involves the brain and increases in severity over time. Alzheimer’s destroys brain cells leading to memory loss, the inability to perform simple tasks, behavioral changes and eventually, death. This destructive disease has no cure, although research is progressing in the areas of treatment, delay of onset, and prevention.
In order to know more about how to treat or cure a disease, scientists must know how it originates. Dr Shaohua Xu at the Florida Space Life Sciences Lab at the Kennedy Space Center has developed a theory regarding the inception of Alzheimer’s disease. Using atomic force microscopy, he has discovered a three step process that turns normal proteins in the brain (called tau) into a mass of tangled threads. These threads are what lead to the death of brain cells resulting in Alzheimer’s disease.
The first step in the process involves the tau molecules clustering together and forming spheres. These spheres grow to a certain, specific, uniform size and then stop [1]. The spheres subsequently joint together into chains, like links on a necklace [1]. In the final step, the chains join to other chains to make the larger structures found in the brain cells of Alzheimer’s patients. These groups of chains, called filaments, congregate in the brain’s cells and do not let them function properly. This leads to the death of the cell. The destruction of enough cells signifies the onset of Alzheimer’s. As more brain cells die, the symptoms of the disease become more pronounced. Eventually, when enough cells have expired, the patient dies.
Dr. Xu’s work is based on colloid science. It is the same principle governing the suspension of fat particles in milk or color particles in paint. [4] When the spheres of abnormal proteins, or colloids, stick together they are called amyloid fibers and develop a very specific structure. They are comprised of lengths of proteins, folded into loops. [1, 3] The fibers overlap into what scientists call a beta sheet structure. [1, 3] This specific structure causes the fiber to be very stable and very difficult for the cell to combat. [3]
Dr. Xu’s discovery has been called revolutionary. “This could be the most important biomedical discovery ever made at Kennedy Space Center,” said a NASA physician, David Tipton, chief of the Aerospace Medicine and Environmental Health Branch at Kennedy Space Center [2]. Researchers around the world are predicting that his discovery will have a tremendous impact on the fight against neurodegenerative diseases. Based on this theory, the progression of the disease may be stopped using drugs that prevent the spheres from forming chains. There are chemicals in use now that hinder this aggregation in paints. The next step will be to find and test drugs that have the potential to stop the filament production and halt the progression of the disease.
References:
1. Xu, S. Cross-beta-sheet structure in amyloid fiber formation. J Phys Chem B. 2009 Sep 17;113(37):12447-55.
2. Nagle, Mike. New Alzheimer’s theory gains NASA backing. LabTechnologist.com.
2008 Jan 30
3. Miranker, Andrew D. Unzipping the mysteries of amyloid fiber formation. Proceedings of the National Academy of Sciences of the United States of America. 2004 March 30;10(13):4335-4336
4. Fisher, Len. How to Dunk a Doughnut: The Science of Everyday Life. Arcade Publishing 2003: 127
