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Nicotine May Slow Progression to Alzheimer's Disease

January 9, 2012 – Nicotine patches may one day slow the progression of mild cognitive impairment (MCI) to Alzheimer’s disease, according to a study Georgetown professors and other researchers will have published tomorrow in the journal Neurology.

Georgetown University Medical Center (GUMC) was one of three academic medical centers participating in the study, which showed that six months of nicotine patch treatment resulted in patients regaining up to 46 percent of normal performance for their age on certain long-term memory tests. The placebo group worsened by 26 percent during that time.

As many as 15 percent of people with MCI progress to Alzheimer’s disease within about a year, according to a 2011 report by the Alzheimer’s Association.

Changing the Course

“We may have some early evidence that could suggest nicotine can change the course of MCI, and possibly slow progression to Alzheimer’s disease,” says Ken Kellar, professor of pharmacology, part of the GUMC team of researchers.

The relatively small clinical trial involved 74 nonsmokers with an average age of 76. Half received the nicotine patch and half a placebo patch for six months. The study was conducted blind, meaning neither the subjects nor the investigators knew who received nicotine and who received a placebo.

Neurology is the medical journal of the American Academy of Neurology. The National Institute of Aging funded the clinical study.

Caution Advised

Kellar, who worked on the study with former GUMC professor Paul Aisen and investigators from Duke University Medical Center and the University of Vermont, say the findings should not be interpreted as a license to put nicotine patches on all people with MCI.

“There are a lot of things we don’t know yet, and so we need to be very cautious,” he says. “Certainly, use of nicotine should be supervised by a physician because it can have side effects in some people.”

But the trial did find that MCI patients tolerated the daily 15-milligram nicotine patch well. These subjects, however, were started on lower doses, which were then increased to the 15 mg. dose.

The study’s lead author, Dr. Paul Newhouse, now of Vanderbilt, also stressed that people with mild memory loss should not use the patches on their own.

“But this study provides strong justification for further research into the use of nicotine for people with early signs of memory loss,” Newhouse says. “We do not know whether benefits persist over long periods of time and provide meaningful improvement.”

Decades of Study

Kellar’s lab has been studying the relationship between Alzheimer’s disease and nicotinic acetylcholine receptors in the brain since the mid-1980s.

The Georgetown scientists found that brains from autopsied Alzheimer’s patients showed a large loss of those receptors, which are stimulated by nicotine and acetylcholine, a neurotransmitter.

That study was confirmed by numerous other investigations internationally, and Kellar hopes the same will happen with the recent study.

“If a lot of people get involved, we could have a definitive answer within just a few short years,” he says. “That’s not too soon for thousands and thousands of people who hope for help as soon as possible.”