Unlocking Alzheimer’s mysteries

About seven million people in the U.S. are living with Alzheimer’s disease, according to the Alzheimer’s Association.

Research shows that some older adults have signs of the disease in their brains after they die, even though they never had symptoms while they were alive.

These cases could be key to developing new treatments.

It’s called asymptomatic Alzheimer’s. Professor Nur Jury-Garfe said that when studying postmortems, these brains show beta-amyloid plaques and tau tangles, which are the two hallmarks of the disease.

“The postmortem diagnosis was ‘oh, this person had Alzheimer’s,’ but when you see, and you go to the clinical records, they were perfectly normal,” Jury-Garfe said.

Now, researchers are trying to determine how these asymptomatic cases avoid cognitive decline. One theory involves immune cells in the brain called microglia and their association with the beta-amyloid plaques.

“You have the plaque, and then in the asymptomatic cases, the microglia is more dynamic, so it can reach the plaque faster. Once it’s there in the plaque, it can embrace the plaque and start fighting and eating all these toxic molecules,” Jury-Garfe said.

If researchers can find a way to mimic these protective mechanisms, it could lead to therapies to help slow the progression of symptoms in someone with the disease.

According to the National Institutes of Health, 30 to 50% of brains donated for research as “healthy” actually show signs of Alzheimer’s.

These donors, who were around 85 years old on average, had no symptoms of the disease while they were alive.