Alzheimer's riddle to be solved
.
Alzheimer's Donation
Donate Online Now
.

US researchers hope to answer an important and long-vexing question about the origins of Alzheimer's disease: Do patients with the condition have high levels of a brain protein because they make too much of it or because they can't clear it from their brains fast enough?
Scientists at the Alzheimer's Disease Research Centre at Washington University School of Medicine in St. Louis say they have developed the first safe and sensitive way to monitor the production and clearance rates of amyloid beta peptide (Abeta) in the human central nervous system. The new testing process could open an important window into the origin of Alzheimer's disease that, in addition to helping scientists better understand the source of the condition, will likely help them improve its diagnosis and treatment, the researchers said.Creation or clearance problems?High levels of Abeta in the brain are a hallmark of Alzheimer's disease and are believed to be a key cause of the condition. Tests that measure Abeta levels in the cerebrospinal fluid have been available for some time. However, those tests gave no hint as to whether Abeta in patients' brains came from an increase in the mechanisms that make the protein or a reduction in the processes that regularly clear it from the brain, the researchers said.
Because Alzheimer's symptoms take many years to develop, some researchers had assumed the creation and clearance rates for Abeta were very slow. But the initial test of the new technique, applied to six healthy volunteers, suggests the opposite.
"Abeta has the second-fastest production rate of any protein whose production rate has been measured so far," says lead author Dr Randall Bateman, assistant professor of neurology at the school. "In a time span of about six or seven hours, you make half the amyloid beta found in your central nervous system."
Ideally, the production and clearance rates stay balanced, causing the overall amount of Abeta in the central nervous system to remain constant. In the healthy volunteers who were the first test subjects, Bateman found the production and clearance rates were the same. He is now applying the technique to individuals with Alzheimer's disease.
Researchers are developing Alzheimer's drugs that either decrease Abeta production or increase its clearance, Bateman said, and the new test could be important in determining which approach is most effective.
The test also may be useful in the diagnosis of Alzheimer's prior to the onset of symptoms, which appear after the disease has inflicted widespread and largely irreversible damage to the brain.
The study appears online June 25 in the journal Nature Medicine. – (HealthDayNews)

Health Highlights: June 26, 2006TMCnet - USA... of amyloid beta peptide (Abeta) in the human central nervous system. The new testing process could open an important window into the origin of Alzheimer's ...
New system may help diagnose, treat Alzheimer'sBelleville News-Democrat - Belleville,IL,USA... Doctors at the school's Alzheimer's Disease Research Center say they have developed the first safe and sensitive way to monitor amyloid beta peptide (Abeta) in ...