This news may put some minds at ease.
Alzheimer’s disease — which affects an estimated 7 million Americans — is notoriously difficult to detect, especially in its initial stages. Researchers from the University of Pittsburgh say they have developed a new biomarker test that may lead to earlier diagnoses and more treatment options.
“Our test identifies very early stages of tau tangle formation — up to a decade before any tau clumps can show up on a brain scan,” said senior study author Thomas Karikari, an assistant professor of psychiatry at Pitt School of Medicine.
Tau is a naturally occurring protein that helps stabilize nerve cells. Along with another protein, amyloid beta, tau can build up in the brain and disturb cell function.
Irregular clumps of tau are called neurofibrillary tangles, which are a hallmark of Alzheimer’s.
The new Pitt test is a spinal tap — a needle extracts cerebrospinal fluid that’s examined for clumping-prone tau.
Karikari and his team pinpointed the primary site where tau molecules can abnormally bind together and form tangles.
“Early detection of tangle-prone tau could identify the individuals who are likely to develop Alzheimer’s-associated cognitive decline and could be helped with new generation therapies,” Karikari said.
There is no known cure for Alzheimer’s, but certain medications can help slow the cognitive decline that’s characteristic of the disease.
Cognitive assessments, brain scans and blood tests are often used to diagnose Alzheimer’s because no single test is definitive.
One exam, a tau PET scan, relies on a radioactive tracer injected into the body to visualize tau protein in the brain.
But it’s not often used in routine clinical practice because it’s expensive, it may not reliably detect early stages of tau pathology and it requires specialized imaging centers.
Other tests measure the level of amyloid beta, which forms plaques in the brain, but Karikari said the clumping of tau is more of a defining event for Alzheimer’s.
“Amyloid beta is a kindling, and tau is a matchstick,” Karikari explained. “A large percentage of people who have brain amyloid-beta deposits will never develop dementia. But once the tau tangles light up on a brain scan, it may be too late to put out the fire and their cognitive health can quickly deteriorate.”
Karikari’s findings were published last week in the journal Nature Medicine.
The spinal tap hasn’t been approved by the US Food and Drug Administration, so it’s not available for use. Researchers hope to eventually make it a blood test.
