As the largest resource of information specific to women's brain health, we are sure you will find what you are looking for, and promise that you will discover new information.
Published on: June 27, 2012
by Janice Wood for Psych Central:
The spread of Alzheimer’s disease through the brain leaves dead neurons and forgotten thoughts in its wake. But researchers haven’t figured out how the disease spread.
Through experiments using stained neurons, a research team at Linköping University in Sweden has been able to demonstrate the process of neurons being invaded by diseased proteins that are then passed on to nearby cells.
“The spread of Alzheimer’s, which can be studied in the brains of diseased patients, always follows the same pattern. But until now, how and why this happens has not been understood,” says Martin Hallbeck, M.D., associate professor of pathology, who led the research team.
The disease starts in the entorhinal cortex — a part of the cerebral cortex — and then spreads to the hippocampus, two areas important for memory. Gradually, pathological changes take place in more and more areas of the brain, while the patient becomes even sicker, the researcher notes.
Two proteins have been identified in connection with Alzheimer’s: beta amyloid and tau. Tau is usually found in the axons — the outgrowths that connect between neurons — where it has a stabilizing function, while beta amyloid seems to have a role in the synapses where the neurons transfer signal substances to each other, Hallbeck said.
But in Alzheimer’s patients, something happens to these proteins, as autopsies reveal abnormal accumulations of both.
Why they become abnormal is still unknown, but what is known is that it’s not the large accumulations, or plaques, that damage the neurons, according to the researchers. Instead, smaller groups of beta amyloid — called oligomeres — seem to be the toxic form that gradually destroy the neurons and shrink the brain.
“We wanted to investigate whether these oligomeres can spread from neuron to neuron, something many researchers tried earlier but didn’t succeed,” Hallbeck said.
The study began with an experiment on neuron cultures, where researchers injected oligomeres stained with a phosphorescent red substance called TMR. The next day the neighboring, connected neurons were also red, which showed that the oligomeres had spread, according to the scientists.
To test whether a sick neuron can “infect” others, they conducted a round of experiments with mature human neurons stained green and mixed with others that were red after having taken up stained oligomeres. After a day, approximately half of the green cells had been in contact with a few of the red ones. After two more days, the axons had lost their shape and organelles in the cell nucleus had started to leak.
“Gradually more and more of the green cells became sick,” Hallbeck said. “Those that hadn’t taken up the oligomeres, on the other hand, weren’t affected.”
The researcher said that if a way of stopping the transfer can be found, it could lead to a more effective way to inhibit the disease.
The study was published in The Journal of Neuroscience.
Are you an apple or a pear? If you’re not sure, look in the mirror. If the image reflecting back to you shows more roundness around the middle of your body, then...
White women whose genes put them at risk of developing Alzheimer’s disease are more likely than white men with similar risk genes to be diagnosed between the ages of 65 and 75, a study drawing on...
Researchers at the Keck School of Medicine of USC are tackling the sixth-leading cause of death in the United States—Alzheimer’s disease—with a new study that intervenes decades before the disease develops. The school is...
The material presented through the Think Tank feature on this website is in no way intended to replace professional medical care or attention by a qualified practitioner. WBHI strongly advises all questioners and viewers using this feature with health problems to consult a qualified physician, especially before starting any treatment. The materials provided on this website cannot and should not be used as a basis for diagnosis or choice of treatment. The materials are not exhaustive and cannot always respect all the most recent research in all areas of medicine.