Recently-published research indicates that a new DNA vaccine could lead to a 50 percent reduction in the number of Alzheimer’s diagnoses made each year. It is the culmination of a ten-year-long study from the Peter O’Donnell Jr. Brain Institute at the University of Texas Southwestern in Dallas. The study’s lead author, Dr. Doris Lambracht-Washington, said, “If the onset of the disease could be delayed by even five years, that would be enormous for the patients and their families.”
The new vaccine has been successfully tested in mice and two other mammal species, indicating that clinical trials in human subjects are not far behind.
Alzheimer’s disease, the most common form of dementia in geriatric patients, is caused by a buildup of plaque due to the accumulation of toxic proteins known as amyloid beta and amyloid tau. Although scientists are not certain how this occurs, the results are well-known: the buildup of amyloids cause a tangle of neurons that interfere with brain function, resulting in the destruction of synapses and brain cells. Currently, Alzheimer’s affects approximately 5.7 million people in the U.S. – a number that is expected to increase by 100 percent over the next 30 years. Currently, there are no treatments for the disease.
A recent study at the University of Florida discovered that a component of the immune system, known as toll-like receptor 5, could be genetically modified in a way that prevents amyloid accumulation in the brain.
This vaccine also targets amyloids by activating an immune response. DNA vaccines are genetically engineered and coded for specific antigens, or proteins designed to elicit a specific immune response. They are usually injected where they are absorbed by cells. The modified proteins present themselves as foreign pathogens similar to bacteria or viruses, thereby activating antibodies.
Earlier attempts to develop such a vaccine resulted in “severe brain swelling” in some test subjects. The latest vaccine has shown no such side effects. A press release from UT Southwestern announced that “…the vaccine is on a shortlist of promising antibody treatments aimed at protecting against both types of proteins that kill brain cells as they spread in deadly plaques and tangles on the brains of Alzheimer’s disease patients.”
If human clinical trials are successful and the new vaccine turns out to be a viable treatment, it will be more of a preventive therapy rather than a cure. It is likely to be most effective in patients whose brains contain high levels of the toxic proteins – but have not yet developed full-blown Alzheimer’s.
Dr. Roger Rosenberg, head of the UT Southwestern Alzheimer’s Disease Center, cautions, “The longer you wait, the less effect it will probably have. Once those plaques and tangles have formed, it may be too late.”
The study appeared in the November 20th edition of Alzheimer’s Research and Therapy.