This is a summary of Vlegels & Knuth et al. Brain-derived tau for monitoring brain injury in acute ischemic stroke. Published in
Science Translational Medicine (2026). DOI: 10.1126/scitranslmed.adz1280

The challenge

In stroke care, key decisions depend on imaging – yet repeated scans are difficult, and imaging provides only intermittent snapshots of a process that can evolve rapidly over hours and days. While other organs have established blood tests to monitor acute injury, the brain still lacks a widely applicable blood-based marker that can reliably reflect ongoing brain damage and serve as a surrogate endpoint in trials.

Our approach

We measured plasma BD-tau with single-molecule assays in a prospective LMU cohort with serial sampling from admission to day 7 (PROMISE; n=502) and validated findings in two independent cohorts: a multicenter observational cohort (DEMDAS; n=519) and a biomarker sub-study embedded in a global, randomized phase-3 thrombectomy trial (ESCAPE-NEXT; n=193).

Our findings

BD-tau rose early after stroke and tracked injury burden and progression: higher early levels were associated with more extensive injury and predicted larger final infarcts, and early increases were linked to infarct growth. BD-tau continued to rise through the first week and was higher in patients with adverse secondary events. Importantly, BD-tau was a strong predictor of recovery, performing at least as well as – and in several analyses better than – other blood biomarkers and imaging metrics for predicting 90-day and longer-term functional outcome.

The implications

Because BD-tau reflects brain injury dynamics and detects treatment-related differences, it could become a practical tool to (i) monitor evolving injury when repeat imaging is limited, (ii) identify complications earlier, and (iii) accelerate proof-of-concept trials by providing a measurable biological readout of treatment response. The authors emphasize that next steps include defining reference ranges and clinically meaningful thresholds and enabling faster measurement (ideally point-of-care).

Creating SyNergies

This work brought together SyNergy expertise in clinical stroke research and systems neurology through SyNergy clinician scientists alongside the broader SyNergy, LMU and international biomarker and trial collaborations.