Researchers at Georgetown University Medical Center say elevated levels of cholesterol may play a bigger part in the development of Alzheimer's disease than originally thought.

"Our study adds to the growing body of evidence implicating high cholesterol as a significant risk factor in Alzheimer's disease, and breaks new ground in showing the damage caused by excessive levels of cholesterol," said Vassilios Papadopoulos, PhD, professor of cell biology and pharmacology.

He and colleagues found that "high cholesterol levels increased the rate at which the amyloid beta peptides break off and form the tangles that kill brain cells."

Amyloid precursor protein (APP) is found in major body organs, but is abnormally processed in Alzheimer's patients and converted to beta amyloid protein that forms thick deposits, or plaques, in the brain.

They also found that high cholesterol increased the production of apolipoprotein E, or APOE preotein, which transports cholesterol out of the cell. And too much APOE, they said, causes an over-accumulation of free cholesterol, which is toxic to human nerve cells.

But they discovered that a certain type of protein, bovine lipoproteins, can actually bind with the cholesterol, allowing the cholesterol to be taken back to the liver, negating harmful effects.

"By giving the dangerous free cholesterol something to bind to, we are paving the way for possible new therapies," Papadopoulos said.

Papadopoulas, who along with Zhi-Xing Yao, assistant professor of cell biology will present the findings at the annual meeting of the Endocrine Society, stressed that many years of study would be necessary before any consequent therapy could be tested in humans.

Other Sources: Georgetown University Medical Center