Cholesterol Levels Linked to Brain Changes of Alzheimer’s Disease
Study: High Cholesterol Predicts Brain-Clogging Protein Deposits on Autopsy
Cholesterol and the Brain continued...
People who keep their cholesterol down as they age might therefore be able to reduce the risk of plaque formation, Sasaki says.
In Alzheimer’s, plaques are usually found in conjunction with another problem called tangles. Tangles are twisted fibers of tau protein that build up inside nerve cells.
It had been thought that a buildup of beta-amyloid might cause tangles and that growing numbers of tangles in the brain might lead to Alzheimer’s symptoms.
Curiously, though, the study found that while cholesterol seemed to be associated with the development of plaques, it did not seem to influence tangles.
“This study lends credence to the notion that there may be different factors driving amyloid pathology versus tangle pathology,” says Marc L. Gordon, MD, chief of Neurology at Zucker Hillside Hospital in Glen Oaks, N.Y. and an Alzheimer’s researcher at The Feinstein Institute for Medical Research in Manhasset, N.Y.
He says the study may mean that sequence of brain damage in Alzheimer’s is less straightforward than “amyloid causes tangles causes disease,” Gordon says.
Important Questions Remain
Experts who reviewed the study for WebMD say its findings are valuable, since few studies have been able to connect blood cholesterol levels to physical changes that happen years later in the brain.
“There’s actually fairly little data on the relationship between cholesterol and Alzheimer’s disease pathology in humans,”says Zoe Arvanitakis, MD, an associate professor in the department of neurological sciences at Rush University Medical Center in Chicago.
“And really there’s little known about the relationship of cholesterol in earlier life to the development of Alzheimer’s disease in later life, and this study tried to get at those two points,” Arvanitakis says.
But Arvanitakis and other experts say the study has important weaknesses that limit what it can say.
“There’s a lot of missing pieces in the chain of evidence in this study,” says Adam Rosenblatt, MD, director of neuropsychiatry at the Johns Hopkins School of Medicine in Baltimore.
Rosenblatt says that although scientists have long suspected that cholesterol plays a role in Alzheimer’s disease, it is still not clear what that may be.