A new biomarker test can detect early-stage tau protein clumping up to a decade before it appears on brain scans, improving early Alzheimer’s diagnosis. Unlike amyloid-beta, tau neurofibrillary tangles are directly linked to cognitive decline.
Years before tau tangles appear in brain scans of Alzheimer’s patients, a biomarker test developed by the University of Pittsburgh School of Medicine can detect small amounts of tau protein prone to clumping, along with its misfolded pathological forms in the brain, cerebrospinal fluid, and possibly blood, according to new research published in Nature Medicine.
This cerebrospinal fluid test correlates with cognitive decline severity, independent of factors such as brain amyloid deposition, offering a potential pathway for early diagnosis and intervention.
Since amyloid-beta abnormalities typically emerge before tau pathology in Alzheimer’s disease, most biomarker research has prioritized detecting amyloid-beta changes. However, the clumping of tau protein into well-ordered structures referred to by pathologists as “neurofibrillary tangles” is a more defining event for Alzheimer’s disease as it is more strongly associated with the cognitive changes seen in affected people.
“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 author Thomas Karikari, Ph.D., assistant professor of psychiatry at Pitt. “Early detection is key to more successful therapies for Alzheimer’s disease since trials show that patients with little-to-no quantifiable insoluble tau tangles are more likely to benefit from new treatments than those with a significant degree of tau brain deposits.”
The Need for a More Reliable Tau Biomarker
Since many elderly people who have amyloid-beta plaques in their brains will never go on to develop cognitive symptoms of Alzheimer’s disease during their lifetime, the widely adopted diagnostics framework developed by the Alzheimer’s Association specifies the three neuropathological pillars necessary to diagnose the disease – combined presence of tau and amyloid-beta pathology and neurodegeneration.
In a quest for early and accessible biomarkers for Alzheimer’s disease, Karikari’s earlier work showed that a brain-specific form of tau, called BD-tau, can be measured in blood and reliably indicate the presence of Alzheimer’s disease-specific neurodegeneration. Several years prior, Karikari showed that specific forms of phosphorylated tau, p-tau181, p-tau217, and p-tau212, in the blood can predict the presence of brain amyloid-beta without the need for costly and time-consuming brain imaging.
But these tools largely detect amyloid pathology, so the issue of early detection of tau still looms large. While tau-PET remains a reliable and accurate predictor of tau burden in the brain, the test’s utility is limited by availability, low resolution, high cost, labor, and sensitivity. At present, tau-PET scans can pick up the signal from neurofibrillary tangles only when a large number are present in the brain, at which point the degree of brain pathology has become pronounced and is not easily reversible.
A Breakthrough in Early Tau Detection
In this latest research, using the tools of biochemistry and molecular biology, Karikari and team identified a core region of the tau protein that is necessary for neurofibrillary tangle formation. Detecting sites within that core region of 111 amino acids, a sequence they call tau258-368, can identify clumping-prone tau proteins and help initiate further diagnostics and early treatment. In particular, the two new phosphorylation sites, p-tau-262 and p-tau-356, can accurately inform the status of early-stage tau aggregation that, with an appropriate intervention, could potentially be reversed.
“Amyloid-beta is a kindling, and tau is a matchstick. 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,” said Karikari. “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.”
Reference: “Phospho-tau serine-262 and serine-356 as biomarkers of pre-tangle soluble tau assemblies in Alzheimer’s disease” by Tohidul Islam, Emily Hill, Eric E. Abrahamson, Stijn Servaes, Denis S. Smirnov, Xuemei Zeng, Anuradha Sehrawat, Yijun Chen, Przemysław R. Kac, Hlin Kvartsberg, Maria Olsson, Emma Sjons, Fernando Gonzalez-Ortiz, Joseph Therriault, Cécile Tissot, Ivana Del Popolo, Nesrine Rahmouni, Abbie Richardson, Victoria Mitchell, Henrik Zetterberg, Tharick A. Pascoal, Tammaryn Lashley, Mark J. Wall, Douglas Galasko, Pedro Rosa-Neto, Milos D. Ikonomovic, Kaj Blennow and Thomas K. Karikari, 10 February 2025, Nature Medicine.
DOI: 10.1038/s41591-024-03400-0
This study was supported by, among others, the National Institute on Aging (grants R01AG083874, U24AG082930, P30AG066468, RF1AG052525-01A1, R01AG053952, R37AG023651, RF1AG025516, R01AG073267, R01AG075336, R01AG072641, P01AG14449, and P01AG025204, among others), the Swedish Research Council (grant 2021-03244), the Alzheimer’s Association (grant AARF-21-850325), the Swedish Alzheimer Foundation, the Aina (Ann) Wallströms and Mary-Ann Sjöbloms Foundation, the Emil and Wera Cornells Foundation and a professorial endowment fund from the Department of Psychiatry, University of Pittsburgh.

News
Specially engineered antibody delivers RNA therapy to treatment-resistant tumors
Elias Quijano, PhD; Diana Martinez-Saucedo, PhD; Zaira Ianniello, PhD; and Natasha Pinto-Medici, PhD, there are 25 other contributors, most from Yale's Department of Therapeutic Radiology and from the departments of genetics, molecular biophysics and [...]
Vaccinated women face fewer cervical cancer risks
New data from Denmark shows the HPV vaccine’s powerful long-term impact, while also revealing why cervical cancer screening is still essential. A Danish study published in the journal Eurosurveillance reports that women who received the human [...]
3D-printed implant offers a potential new route to repair spinal cord injuries
A research team at RCSI University of Medicine and Health Sciences has developed a 3-D printed implant to deliver electrical stimulation to injured areas of the spinal cord, offering a potential new route to [...]
Nanocrystals Carrying Radioisotopes Offer New Hope for Cancer Treatment
The Science Scientists have developed tiny nanocrystal particles made up of isotopes of the elements lanthanum, vanadium, and oxygen for use in treating cancer. These crystals are smaller than many microbes and can carry isotopes of [...]
New Once-a-Week Shot Promises Life-Changing Relief for Parkinson’s Patients
A once-a-week shot from Australian scientists could spare people with Parkinson’s the grind of taking pills several times a day. The tiny, biodegradable gel sits under the skin and releases steady doses of two [...]
Weekly injectable drug offers hope for Parkinson’s patients
A new weekly injectable drug could transform the lives of more than eight million people living with Parkinson's disease, potentially replacing the need for multiple daily tablets. Scientists from the University of South Australia [...]
Most Plastic in the Ocean Is Invisible—And Deadly
Nanoplastics—particles smaller than a human hair—can pass through cell walls and enter the food web. New research suggest 27 million metric tons of nanoplastics are spread across just the top layer of the North [...]
Repurposed drugs could calm the immune system’s response to nanomedicine
An international study led by researchers at the University of Colorado Anschutz Medical Campus has identified a promising strategy to enhance the safety of nanomedicines, advanced therapies often used in cancer and vaccine treatments, [...]
Nano-Enhanced Hydrogel Strategies for Cartilage Repair
A recent article in Engineering describes the development of a protein-based nanocomposite hydrogel designed to deliver two therapeutic agents—dexamethasone (Dex) and kartogenin (KGN)—to support cartilage repair. The hydrogel is engineered to modulate immune responses and promote [...]
New Cancer Drug Blocks Tumors Without Debilitating Side Effects
A new drug targets RAS-PI3Kα pathways without harmful side effects. It was developed using high-performance computing and AI. A new cancer drug candidate, developed through a collaboration between Lawrence Livermore National Laboratory (LLNL), BridgeBio Oncology [...]
Scientists Are Pretty Close to Replicating the First Thing That Ever Lived
For 400 million years, a leading hypothesis claims, Earth was an “RNA World,” meaning that life must’ve first replicated from RNA before the arrival of proteins and DNA. Unfortunately, scientists have failed to find [...]
Why ‘Peniaphobia’ Is Exploding Among Young People (And Why We Should Be Concerned)
An insidious illness is taking hold among a growing proportion of young people. Little known to the general public, peniaphobia—the fear of becoming poor—is gaining ground among teens and young adults. Discover the causes [...]
Team finds flawed data in recent study relevant to coronavirus antiviral development
The COVID pandemic illustrated how urgently we need antiviral medications capable of treating coronavirus infections. To aid this effort, researchers quickly homed in on part of SARS-CoV-2's molecular structure known as the NiRAN domain—an [...]
Drug-Coated Neural Implants Reduce Immune Rejection
Summary: A new study shows that coating neural prosthetic implants with the anti-inflammatory drug dexamethasone helps reduce the body’s immune response and scar tissue formation. This strategy enhances the long-term performance and stability of electrodes [...]
Scientists discover cancer-fighting bacteria that ‘soak up’ forever chemicals in the body
A family of healthy bacteria may help 'soak up' toxic forever chemicals in the body, warding off their cancerous effects. Forever chemicals, also known as PFAS (per- and polyfluoroalkyl substances), are toxic chemicals that [...]
Johns Hopkins Researchers Uncover a New Way To Kill Cancer Cells
A new study reveals that blocking ribosomal RNA production rewires cancer cell behavior and could help treat genetically unstable tumors. Researchers at the Johns Hopkins Kimmel Cancer Center and the Department of Radiation Oncology and Molecular [...]