Two key hallmarks of Alzheimer’s disease are tangles of tau proteins that form inside neurons and amyloid plaques that build up between the neurons. Brain scans and spinal taps are useful for detecting these abnormalities, but Thomas Karikari wants to give patients a less invasive option: a simple blood test. (Photo Credit: Tom Altany/University of Pittsburgh)

“We need to find the best ways of understanding and identifying individuals who may be at risk,” says Karikari, a neuroscientist at the University of Pittsburgh. A blood test, he says, “can provide a snapshot of what’s happening in the brain, even up to 20 years before symptoms manifest.”

Early in Karikari’s career, the consensus around blood-based tests was one of incredulity. As a postdoctoral student, he set himself the challenge of designing a blood test that can detect a form of tau called p-tau181, which exists in high levels in the brains of people who have Alzheimer’s and accumulates as the disease progresses.

After screening dozens of antibodies, Karikari and his collaborators discovered that the part of tau commonly detected in blood is the left end section not the middle part that spinal-fluid tests usually target. This insight helped them design antibodies that could bind to the left portion of the tau protein. The team went on to develop a blood test that detects p-tau181 with an accuracy of more than 82%.

What challenges limit widespread use?
Labs use different methods to measure the same protein, which means results aren’t always consistent. And because tau is also common in the liver, kidney, heart and other organs, “we might run into some false positivity” when it’s detected in the blood. One of his team’s tests specifically targets brain-derived tau.

What drives the push for accessibility?
A key goal is making tests usable in places such as his home village of Manfo in Ghana. His lab has developed a pared-back method requiring smaller blood samples and “remote-friendly tools,” such as a collection tube that can store blood at room temperature for up to 96 hours. “I will feel most accomplished when all that we are doing gets to reach my village,” he says.

Source: https://www.adrc.pitt.edu/three-rising-stars-in-ageing-research/