Vaccine Patch Developed for Alzheimer's Disease

An innovative needle-free vaccine approach has been found to be effective and safe in clearing brain-damaging plaques from a mouse model of Alzheimer's disease (AD).

The transdermal (across the skin) vaccination, may provide a simpler way of preventing or treating the devastating neurodegenerative disease with less probability of adverse immune reactions. The study was published online January 22, 2007, in the journal Proceedings of the [U.S.] National Academy of Sciences.

"While many groups have shown vaccinating against the beta amyloid protein [Ab] can reduce Alzheimer's-like pathology including certain cognitive deficits, this study is the first to demonstrate that immunization using the skin may be an effective way to reduce Ab pathology,” said senior study author Jun Tan, Ph.D., M.D., director of the Neuroimmunology Laboratory at the Institute for Research in Psychiatry, department of psychiatry at University of South Florida (USF; Tampa, FL, USA).

"The beauty is that something as simple and non-invasive as a skin patch could potentially be a promising therapy for Alzheimer's disease,” said study coauthor USF investigator, Terrence Town, Ph.D.

The Alzheimer's vaccine functions by triggering the immune system to recognize Ab--a protein that abnormally builds up in the brains of Alzheimer's patients--as a foreign invader and attack it. Earlier studies on an injectable AD vaccine proven safe and effective in an animal model were suspended indefinitely when the initial clinical trial caused brain inflammation and death in a small percentage of patients. These serious side effects were secondary to an autoimmune reaction, which occurred when immune cells aggressively attacked the body's own proteins generated by the vaccine.

The USF researchers targeted the skin as the route of vaccine delivery in mice bred to develop age-related brain degeneration imitating AD. They discovered that transdermal immunization with Ab does not seem to initiate specific toxicities associated with earlier immunization strategies.

Specialized immune cells prevalent in the skin, called Langerhans, may direct the body's reaction to the vaccine toward a response that is beneficial instead of overly aggressive and ultimately harmful, according to Dr. Tan. The USF researchers plan to further evaluate whether the transdermal vaccine can reduce memory loss in AD mice as well as curb their "senile” plaque load. "If those studies show clear cognitive benefits,” Dr. Tan said, "we believe clinical trials to evaluate a beta amyloid skin patch or topical cream in patients with Alzheimer's would be warranted.”




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