A blood test may help identify individuals at risk for Alzheimer’s before they show any signs of the disease, according to a new study published in the journal Nature Medicine.
The blood test looks at the activity of star-shaped brain cells in the blood called astrocytes, according to researchers from the University of Pittsburgh School of Medicine.
Only patients whose brains showed a combination of “abnormally reactive” astrocytes and high accumulations of amyloid — one of the proteins that is linked to Alzheimer’s — went on to develop cognitive symptoms of the disease, per the study findings.
“This puts astrocytes at the center as key regulators of disease progression, challenging the notion that amyloid is enough to trigger Alzheimer’s disease,” senior author Tharick Pascoal, M.D., PhD, an associate professor of psychiatry and neurology at the University of Pittsburgh School of Medicine, said in a news release.
Astrocytes are specialized cells in the brain that supply nerve cells with nutrients and serve other protective functions, according to Verywell Health.
Signs of Alzheimer’s in the brain
Alzheimer’s is a degenerative condition that affects the brain, resulting in a progressive loss of memory and the onset of dementia.
Brain scientists believed for decades that one telltale sign of the disease — and a possible direct culprit — was an accumulation of amyloid plaques and concentrations of protein fibers called “tau tangles,” according to the University of Pittsburgh’s press release.
Researchers have been puzzled, however, by a significant share of individuals whose brains appear to be “chock-full of toxic amyloid aggregates” yet never go on to develop Alzheimer’s-associated dementias.
The new findings may help solve this mystery, the study authors noted in the release.
The role of inflammation in Alzheimer’s disease has been the focus of many ongoing clinical trials.
“Our study argues that testing for the presence of brain amyloid along with blood biomarkers of astrocyte reactivity is the optimal screening to identify patients who are most at risk for progressing to Alzheimer’s disease,” Pascoal said in the release.
Blood test results could be a ‘game changer’
During the study, researchers tested the blood of more than 1,000 cognitively unimpaired elderly people with and without signs of amyloid in the brain.
The study showed that only those who were positive for both amyloid protein accumulations and increased astrocyte reactivity showed evidence of progressively developing tau pathology, which experts said might predispose a person to develop clinical symptoms of Alzheimer’s disease.
“Astrocytes coordinate [the] brain amyloid and tau relationship like a conductor directing the orchestra,” Bruna Bellaver, PhD, lead author of the study and a postdoctoral associate at the University of Pittsburgh, said in the release.
“This can be a game changer [in] the field, since glial biomarkers in general are not considered in any main disease model,” Bellaver added.
Nearly two years ago, Pascoal and his team of researchers found that inflammation of brain tissue triggered the spread of “pathologically misfolded proteins in the brain and is a direct cause of eventual cognitive impairment in patients with Alzheimer’s disease,” according to the release.
The role of inflammation in Alzheimer’s disease has been the focus of many ongoing clinical trials, Dr. Marc L. Gordon, chief of neurology at Zucker Hillside Hospital in Manhasset, New York, told Fox News Digital in an interview.
Gordon was not part of the study but has conducted research on Alzheimer’s disease.
“It’s not just amyloid and tau, but neuro-inflammation” that potentially play an important role in the cognitive decline associated with Alzheimer’s disease, he said.
This new study “is another piece of the puzzle,” Gordon said, as it helps identify individuals who are not yet experiencing symptoms of the disease but could possibly benefit from treatments to halt its progression.
“The notion here is that if you could identify a subset of the people who are cognitively normal but have amyloid present … on the basis of this biomarker for inflammation, those would be the people who you may want to test a new drug on,” he added.
With clinical trials starting to include people at earlier stages of pre-symptomatic disease, accurate early diagnosis of Alzheimer’s risk is critical for success, brain experts shared with Fox News Digital.
Including astrocyte reactivity markers in the panel of diagnostic tests could help identify candidates at risk for Alzheimer’s disease for future research studies, the University of Pittsburgh researchers stated in the release.
More than six million people in the U.S. have Alzheimer’s, 73% of whom are 75 or older, according to the Alzheimer’s Association.