New research provides evidence that sleep-driven glymphatic activity moves amyloid beta and tau out of the brain and into the bloodstream.
Key takeaways:
- A randomized crossover study of 39 participants found that normal sleep significantly increased morning plasma levels of amyloid beta and tau compared to sleep deprivation.
- Researchers interpret these elevated blood levels as evidence of the glymphatic system clearing proteins from brain tissue into the bloodstream during sleep.
- The study utilized a novel device to monitor brain electrical activity and cerebrovascular dynamics, identifying a specific sleep-related glymphatic signature.
- The findings support the development of therapeutics targeting glymphatic clearance for the early treatment or prevention of Alzheimer’s disease.
A randomized crossover study conducted by researchers at Applied Cognition and published in Nature Communications links sleep-related glymphatic activity to specific shifts in blood biomarkers for amyloid beta and tau.
The findings suggest that physiological processes occurring during sleep play a central role in removing toxic proteins associated with neurodegeneration. In the trial, which included 39 participants, researchers observed that normal sleep significantly increased morning plasma levels of amyloid beta and tau compared to periods of sleep deprivation.
According to the investigators, these higher levels in the blood indicate that the proteins are being actively cleared from brain tissue and moved into the bloodstream overnight—a mechanism previously hypothesized but now demonstrated in humans.
“This study confirms something profoundly important, that the human brain has an active, sleep-driven clearance system, and when sleep neurophysiology is disrupted, that system fails,” says Paul Dagum, MD, PhD, CEO and co-founder of Applied Cognition, in a release. “These findings directly validate Applied Cognition’s therapeutic strategy to enhance glymphatic clearance as a disease-modifying approach for early Alzheimer’s disease.”
The study methodology paired advanced plasma biomarker analysis with continuous overnight monitoring. Researchers used a novel device developed by Applied Cognition, recently validated in Nature Biomedical Engineering, to capture brain electrical activity (EEG), cerebrovascular dynamics, and neurophysiological measures of fluid transport.
The combined data revealed a distinct sleep-related glymphatic signature characterized by deep-sleep EEG patterns, increased cerebrovascular pulsatility, and decreased resistance to fluid flow within the brain.
“Our findings provide the first causal human evidence that sleep-active glymphatic transport clears amyloid beta and tau,” says Jeffrey Iliff, PhD, a professor of psychiatry at the University of Washington School of Medicine, in a release. “This work brings together over a decade of research in rodents supporting a role for glymphatic transport in the clearance of amyloid beta and tau from the brain and shows that these same processes are indeed operating in the human brain.”
Applied Cognition, a clinical-stage platform therapeutics company, intends to use these results to advance its strategy of developing interventions that enhance the brain’s intrinsic clearance pathways. By establishing a link between sleep physiology, biomarker dynamics, and glymphatic transport, the study highlights glymphatic function as a modifiable therapeutic target for Alzheimer’s disease prevention and treatment.
