A researcher's hunch — made more than 20 years ago in a Kentucky medical examiner's office — may soon lead to a new treatment for Alzheimer's disease.
The treatment is the brainchild of D. Larry Sparks, PhD, now head of the Roberts Laboratory for Neurodegenerative Disease Research at Sun Health Research Institute in Sun City, Ariz.
"We may have found a new medication that will be of benefit in the treatment — and hopefully, in slowing the progression — of neurodegenerative disorders," Sparks tells WebMD.
Though the treatment is new — it seeks to remove excess cholesterol from the brains of Alzheimer's patients — the drug being tested is very familiar. It's Lipitor, a widely used member of the family of cholesterol-lowering drugs called statins.
Sparks is quick to point out that only large clinical trials can prove whether or not Lipitor really helps people with Alzheimer's disease. Two such trials are under way. Early results are expected in about two years.
"Everybody has great hope for these studies," Alzheimer's Association spokesman Bill Thies, MD, tells WebMD. "We are waiting on these bigger trials to take the next step, before saying anyone with dementia should be on statins."
Medical Detective Fingers Alzheimer's Suspect: Cholesterol
Two decades ago, Sparks noticed something nobody else had seen. At the time, everyone thought that brain-clogging amyloid plaques could be seen only in the brains of people with Alzheimer's disease. Yet Sparks found them in the brains of people who had died from coronary artery disease — the buildup of cholesterol in the walls of arteries.
Animal and laboratory studies convinced Sparks — and his doubting colleagues — that excess cholesterol in the brain is, indeed, linked to Alzheimer's disease.
According to the American Heart Association, elevated cholesterol is an important risk factor for Alzheimer's disease. But can lowering cholesterol in the blood improve brain function in people with Alzheimer's disease?
Maybe. Last year, Sparks reported encouraging early results from a study in which people with mild to moderate Alzheimer's disease took Lipitor. Now Sparks and colleagues report their final results, based on 63 Alzheimer's patients who finished at least three months of Lipitor treatment.
"Patients were better after six months of treatment than they were at the start," Sparks tells WebMD. "It was noticeable to their doctors at the end of a year. There were patients who were on Lipitor for a whole year and then went off it. And after a month, their family members said to put them back on the drug. So the improvement is enough for families to notice the difference."
People who have Alzheimer's disease can have depression that typically worsens as the disease progresses. Unexpectedly, the Alzheimer's patients who took Lipitor were significantly less depressed than they were at the beginning of the study.
The Role of Cholesterol in the Blood
How could Lipitor help Alzheimer's patients? Excess cholesterol in the brain seems to play a role in Alzheimer's disease progression. Sparks theorized that if patients had less cholesterol in their blood, their blood could act as a sponge to draw extra cholesterol out of the brain.
The actual biochemical process is, of course, more complicated than that. If it worked, cholesterol lowering wouldn't have an immediate effect.
"You would expect a delayed clinical benefit if this is the case," Sparks says. "That is exactly what we found. The clinical measures of cognitive function deteriorate for the first three months of treatment. But at six months there was this improvement."
Sparks and colleagues report their findings in the May issue of Archives of Neurology.
Lower Cholesterol to Prevent Alzheimer's Disease
Both Sparks and Thies say it's too soon to think of Lipitor or similar drugs as treatments for Alzheimer's disease. But Thies, Alzheimer's Association vice president for medical and scientific affairs, notes that the Alzheimer's Association already urges people to cut their risk of Alzheimer's disease by keeping their cholesterol at recommended levels.
"There are a lot of good reasons for people to take statin drugs," Thies says. "You should track your cholesterol numbers to see if statin treatment is appropriate for you or not. This is not a clarion call to take statins to prevent dementia. But if you are not taking statins — and need them to control high cholesterol — that is probably a bad thing."
Lipitor is manufactured by Pfizer, a WebMD sponsor.
SOURCES: Sparks, D.L. Archives of Neurology, May 2005; vol 62: pp 753-757. Raffaï, R.L. and Weisgraber, K.H. Journal of Lipid Research, 2004; vol 44: pp 1423-1430. D. Larry Sparks, PhD, director, Roberts Laboratory for Neurodegenerative Disease Research, Sun Health Research Institute, Sun City, Ariz. Bill Thies, MD, vice president for medical and scientific affairs, Alzheimer's Association. WebMD Medical News: "Cholesterol Drug May Slow Alzheimer's Disease."