Immune cells are an ally, not enemy, in battle against Alzheimer's

January 29, 2015 by Bill Hathaway
Immune cells are an ally, not enemy, in battle against Alzheimer’s
The cell in green is a microglia, an immune system cell that is blocking free floating beta amyloid (in red) as it binds to amyloid plaque (blue), the hallmark of Alzheimer’s Disease. Yale researchers found that rather than a marker for damaging inflammation, these cells protect the brain from free floating amyloid.

Beta-amyloid is a sticky protein that aggregates and forms small plaques in the brains of the elderly and is thought to be a cause of Alzheimer's disease. Because specialized immune cells always surround these plaques, many have theorized that these cells are responsible for inflammation and damage to surrounding brain cells.

That theory appears to be wrong, according to a new study by Yale School of Medicine researchers published in the Jan. 29 issue of Nature Communications. Instead of causing damage, these brain —called microglia—seem to protect the brain by keeping corralled, the paper shows.

Previous research had shown that some people with large accumulations of plaques do not necessarily have symptoms of dementia, which led researchers to search for other causes of . Inflammation was one of potential culprits identified by scientists. However Alzheimer's drugs that target inflammation in the brain have failed to show any benefit.

"The idea that is always bad is a simplistic view and is probably wrong when talking about Alzheimer's," said Jaime Grutzendler, associate professor in the Department of Neurology and senior author of the study. "In fact, as we age we lose microglia and become less able to confine plaques, leading to the release of plaque toxins that destroy the connections between neurons."

The new study using high-resolution imaging technology revealed that in the brains of mice, microglia actually act as a physical barrier that slows the expansion of plaques and blocks the ability of free-floating beta-amyloid proteins to bind to the plaques and cause toxicity.

"One possibility is that microglia nicely insulate the rest of the brain from plaques and may explain why some people with them do not experience severe cognitive decline," Grutzendler said. "By improving microglia's shielding function, we were able to reduce toxicity to neurons."

This insight could lead to new treatments for the disease, he added.

Explore further: In elderly, hardening of arteries linked to plaques in brain

Related Stories

In elderly, hardening of arteries linked to plaques in brain

October 16, 2013
Even for elderly people with no signs of dementia, those with hardening of the arteries are more likely to also have the beta-amyloid plaques in the brain that are a hallmark of Alzheimer's disease, according to a study published ...

Clue to cause of Alzheimer's dementia found in brain samples

October 22, 2012
Researchers at Washington University School of Medicine in St. Louis have found a key difference in the brains of people with Alzheimer's disease and those who are cognitively normal but still have brain plaques that characterize ...

Suppressing protein may stem Alzheimer's disease process

April 25, 2013
Scientists funded by the National Institutes of Health have discovered a potential strategy for developing treatments to stem the disease process in Alzheimer's disease. It's based on unclogging removal of toxic debris that ...

New findings on the brain's immune cells during Alzheimer's disease progression

April 11, 2013
The plaque deposits in the brain of Alzheimer's patients are surrounded by the brain's own immune cells, the microglia. This was already recognized by Alois Alzheimer more than one hundred years ago. But until today it still ...

Protein that rouses the brain from sleep may be target for Alzheimer's prevention

November 24, 2014
A protein that stimulates the brain to awaken from sleep may be a target for preventing Alzheimer's disease, a study by researchers at Washington University School of Medicine in St. Louis suggests.

Recommended for you

Multi-gene test predicts Alzheimer's better than APOE E4 alone

September 22, 2017
A new test that combines the effects of more than two dozen genetic variants, most associated by themselves with only a small risk of Alzheimer's disease, does a better job of predicting which cognitively normal older adults ...

Personality changes don't precede clinical onset of Alzheimer's, study shows

September 21, 2017
For years, scientists and physicians have been debating whether personality and behavior changes might appear prior to the onset of Alzheimer's disease and related dementias.

Newly ID'd role of major Alzheimer's gene suggests possible therapeutic target

September 20, 2017
Nearly a quarter century ago, a genetic variant known as ApoE4 was identified as a major risk factor for Alzheimer's disease—one that increases a person's chances of developing the neurodegenerative disease by up to 12 ...

Is the Alzheimer's gene the ring leader or the sidekick?

September 15, 2017
The notorious genetic marker of Alzheimer's disease and other forms of dementia, ApoE4, may not be a lone wolf.

Potential noninvasive test for Alzheimer's disease

September 6, 2017
In the largest and most conclusive study of its kind, researchers have analysed blood samples to create a novel and non-invasive way of helping to diagnose Alzheimer's disease and distinguishing between different types of ...

Researchers unlock the molecular origins of Alzheimer's disease

September 6, 2017
A "twist of fate" that is minuscule even on the molecular level may cause the development of Alzheimer's disease, VCU researchers have found.

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.