Roanoke Times
Copyright (c) 1995, Landmark Communications, Inc.
DATE: TUESDAY, November 7, 1995 TAG: 9511070057
SECTION: NATIONAL/INTERNATIONAL PAGE: A-1 EDITION: METRO
SOURCE: Associated Press
DATELINE: DURHAM, N.C. LENGTH: Medium
The new understanding offers numerous possibilities for the development of drugs that might not ``cure'' the disease but could delay it for 20 years, meaning most people would not live long enough to get it, said Dr. Allen Roses, chairman of the neurology department at Duke University Medical Center.
Speaking Monday at a meeting sponsored by the Council for the Advancement of Science Writing, Roses also reported that people with the Alzheimer's gene are more likely than others to die after a head injury, because of the weakened condition of their neurons, or nerve cells.
The gene produces a substance called apolipoprotein E4, or apo E4, which shuttles cholesterol through the bloodstream.
Roses' belief that apo E4 is critical in Alzheimer's puts him at odds with some other leading authorities.
``No one disputes that E4 is important. E4 is a risk factor, not the cause,'' said Dr. Dennis Selkoe, a neurologist at Harvard Medical School.
Selkoe believes that E4 somehow changes the form of a substance called amyloid in the brain. The brains of Alzheimer's victims are laced with amyloid plaques, or deposits, that Selkoe and others believe are the central feature of Alzheimer's disease.
Roses said he believes that amyloid is an incidental consequence of damage produced by apo E4, and that amyloid is not central to the disease itself.
For years, apo E4 had been known to be linked to an increased risk of heart disease. In 1993, Roses reported a link between apo E4 and Alzheimer's.
About 2 percent of Americans have two copies of the apo E4 gene, giving them a 50 percent chance of getting Alzheimer's before age 70. In contrast, for those with no copies of the apo E4 gene, the risk of developing the disease does not rise to 50 percent until after age 90.
About one-third of Americans have one copy, which puts them at intermediate risk.
An estimated 4 million Americans suffer from Alzheimer's disease, and 100,000 die of it every year. It is the fourth leading cause of death in adults after heart disease, cancer and stroke. It usually strikes after age 65.
by CNB