Related Experiment Video
Updated: Oct 21, 2026
A Pilot Study on the Repetitive Transcranial Magnetic Stimulation of Aβ and Tau Levels in Rhesus Monkey Cerebrospinal Fluid
Published on: September 3, 2021
Brain-derived tau in plasma and cerebrospinal fluid after surgery: a prospective cohort substudy
Martin Thorsson1, Lars I Eriksson2, Mattias Danielson3
1Department of Anesthesiology and Intensive Care, Institute of Clinical Sciences, The Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden; Department of Anesthesiology and Intensive Care, Sahlgrenska University Hospital/Sahlgrenska, Gothenburg, Sweden.
Background:
Postoperative increases in plasma total tau (t-tau) protein have raised concerns that surgery can cause CNS injury. Brain-derived tau (BD-tau) is a novel biomarker that quantifies CNS-derived tau. We assessed BD-tau concentrations in plasma and CSF after surgery to investigate neuronal injury and mechanisms driving increases in plasma t-tau.
Methods:
This was a substudy of a previous prospective cohort study enrolling adult patients undergoing hip and knee arthroplasty. We measured plasma and CSF BD-tau and t-tau before neuraxial anaesthesia (baseline) and at 4, 8, 24, 32, and 48 h after surgery and assessed cognitive performance at baseline and 3 months. Biomarker concentrations are reported as median (IQR) percentage change from baseline.
Results:
Plasma BD-tau peaked at 4 h with a 254% increase (137-382%, P<0.001) and remained elevated by 31% (6-75%, P<0.001) at 48 h. CSF BD-tau was unchanged at 4 h but increased by 51% (21-82%, P=0.004) at 48 h. Plasma BD-tau was associated with plasma t-tau (β=1.09, 95% CI 0.95-1.23, P<0.001), whereas plasma BD-tau and CSF BD-tau were inversely associated (β=-0.71, -0.97 to -0.45, P<0.001). Higher postoperative plasma BD-tau was associated with both higher CSF albumin and worse cognitive performance at 3 months.
Conclusions:
Early postoperative increases in plasma t-tau are consistent with a CNS origin but not concomitant neuronal injury. Instead, the early plasma BD-tau increase and the inverse association between CSF and plasma BD-tau could indicate a redistribution of tau from the CNS to plasma.
