Brain-derived tau biomarker can predict patient outcomes and reveal treatment effects, potentially serving as point-of-care diagnostic tool.
Researchers have identified a blood biomarker that can track the extent of brain injury after ischemic stroke over time and predict patient functional outcomes months to years later.
The biomarker, brain-derived tau (BD-tau), captures tau protein originating from the central nervous system and reflects disease progression in ways that current imaging cannot provide. The study, led by Ludwig-Maximilians-Universität München and published in Science Translational Medicine, analyzed data from more than 1,200 stroke patients across multiple cohorts.
“In stroke care, we currently face the problem that we cannot continuously track how brain injury evolves over time – and this limits our treatment decisions,” says Steffen Tiedt, PhD, MD, scientist at the Institute for Stroke and Dementia Research and attending physician in the stroke unit at LMU University Hospital’s Department of Neurology, in a release.
Biomarker Performance and Clinical Applications
Blood levels of BD-tau correlated with brain injury severity, with early measurements taken within hours of symptom onset associated with initial damage and predictive of final infarct size. The biomarker also captured disease dynamics, showing larger increases during the first 24 to 48 hours linked to infarct growth and elevated levels during complications such as recurrent events.
BD-tau proved to be a strong predictor of recovery, forecasting functional outcome at 90 days and beyond at least as well as, or better than, other blood biomarkers and imaging-based infarct volumes. The biomarker also revealed treatment effects, rising less after thrombectomy when vessels were fully reopened.
In a randomized clinical trial, BD-tau increases were markedly smaller with the neuroprotectant nerinetide compared to placebo, demonstrating the biomarker’s ability to detect therapeutic responses.
Addressing Current Diagnostic Limitations
Current stroke diagnosis relies heavily on CT or MRI scans, which provide only point-in-time information during the acute phase. Repeated imaging is logistically demanding and not always feasible, while imaging measures often reflect later recovery only to a limited extent.
While acute injury to organs like the heart or kidneys can be monitored with blood tests, the brain has lacked such a marker until now. The research team initiated their study in 2013 to develop a reliable blood test that could continuously reflect brain injury and make treatment effects measurable.
The LMU University Hospital study cohort measured BD-tau repeatedly from hospital admission through day seven, with findings validated in two independent multicenter cohorts, including a biomarker-based analysis within a phase 3 clinical trial.
Future Development and Applications
“We don’t just need a picture from the beginning of a stroke; we need a way to follow the course of brain injury over time. BD-tau could become a kind of ‘troponin for the brain,’ an objective blood marker that makes progression and treatment effects measurable,” says Tiedt in a release.
The researchers note that further studies are needed to define reference ranges and thresholds and to enable faster measurement of BD-tau, ideally as a point-of-care test. Such a blood test could help clinicians monitor disease trajectories more closely, detect complications earlier, and evaluate new therapies more efficiently in clinical trials.
BD-tau may also have applications for objectively and rapidly assessing brain injury in other neurological diseases beyond stroke.
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