Finnish researchers tested whether manipulating blood vessels could push proteins out of the human brain and into the bloodstream. Twenty-nine healthy adults aged 27 to 61 received sublingual nitroglycerin, a nitric oxide donor that relaxes arteries and lowers blood pressure, combined with 37 minutes of patterned whole-body vibration designed to stimulate the mechanosensitive Piezo1 channel. After the combined session, blood levels of amyloid-beta 40, amyloid-beta 42 and the astrocyte protein GFAP rose by roughly 30 to 35 percent, and the size of the rise tracked how far blood pressure fell. MRI showed brain tissue signal darkening, more fluid around the brain and brighter signal in posterior venous sinuses. Larger proteins, neurofilament light and phosphorylated tau, did not change. The findings hint at a non-invasive way to boost brain clearance, but the study was small and short, and its key blood measurements had no control arm.
Every night while you sleep, your brain rinses itself. Cerebrospinal fluid washes through brain tissue and carries away waste proteins, including the amyloid-beta that clumps into plaques in Alzheimer’s disease. This plumbing, often called the glymphatic system, appears to falter with age, and many researchers suspect the failure begins years before memory does. A team led by Vesa Kiviniemi at the University of Oulu in Finland asked a direct question: can we turn that drainage up in awake humans?
Their approach targeted the blood vessels that drive brain fluid flow. Nitric oxide relaxes arteries, and in mice, lowering blood pressure with nitric oxide donors pushes cerebrospinal fluid tracers out of the skull and into the blood. A second lever is Piezo1, a channel in vessel walls that responds to mechanical force. Gentle mechanical stimulation of Piezo1 in mice restores sluggish lymphatic drainage in the neck. The Finnish group combined both. Volunteers placed a nitroglycerin tablet under the tongue, the same drug used for angina, then lay on a vibrating mattress that cycled between 22 and 50 hertz in a pattern meant to keep Piezo1 responsive rather than numb.
The results were clear in direction, if modest in scale. Blood pressure fell by about 15 percent at its lowest point. Blood levels of two forms of amyloid-beta and of GFAP, a protein made by the brain’s astrocyte support cells, rose by roughly a third after correcting for the blood thinning that nitroglycerin causes. People whose blood pressure dropped the most showed the biggest protein rises. Two larger brain proteins, neurofilament light and phosphorylated tau, did not budge, which the authors read as a size filter on the exit route.
Brain scans told a parallel story. A clinical MRI sequence sensitive to the protein content of water showed the whole brain darkening slightly, the fluid space around the brain expanding by about 6.5 milliliters, and signal brightening in two large veins at the back of the head. Blood amyloid levels correlated, weakly, with that venous signal. Changes were larger in older participants. Nitroglycerin alone reproduced much of the brain darkening, vibration alone did little the scanner could detect, and the combination affected a wider area of brain than either alone.
The authors draw a parallel to sleep. Nitroglycerin amplified slow oscillations in blood vessel diameter near 0.1 hertz and breathing-linked pulsations, rhythms that intensify in deep sleep and are thought to pump fluid through the brain.
The study has important gaps. It enrolled 29 healthy adults and measured blood proteins once, about 90 minutes after treatment. It did not measure blood proteins at all after vibration alone, nitroglycerin alone or a sham session. A rise in blood amyloid could mean more protein leaving the brain, but it could also mean slower removal of amyloid by the liver and kidneys while blood pressure is low, or a temporary loosening of the blood-brain barrier. Nobody yet knows whether repeated treatment would lower brain amyloid or protect memory.
What the paper does establish is that human brain fluid dynamics respond measurably, within a couple of hours, to deliberate vascular manipulation. That moves the brain’s drainage system closer to being a practical therapeutic target rather than a purely theoretical one.
Insights
- In this trial, one volunteer taking nitroglycerin vomited and withdrew, and others had headaches or nausea. Combining nitrates with PDE5 inhibitors such as tadalafil or sildenafil can cause dangerous, potentially fatal drops in blood pressure. For repeated or long-term use for this purpose: Safety Data Absent.
- The benefit measured is a short-term biomarker shift, not a health outcome. Blood amyloid rose about a third, a moderate effect (Cohen’s d about 0.5, meaning the average person moved about half of the normal person-to-person spread). The size of the blood pressure drop explained roughly 25 to 40 percent of the variation in that rise. Memory, plaque load and dementia risk were not measured.
- Deep sleep naturally produces similar vascular pulsations. Long-term blood pressure control has real outcome data: in the SPRINT MIND trial, intensive control lowered the risk of mild cognitive impairment by about 19 percent (hazard ratio 0.81).
- Vibration platforms are low risk, but here vibration alone produced only small imaging changes and was never tested on blood biomarkers.
- Endothelial nitric oxide production declines with age. Regular aerobic exercise is the best-documented way to maintain it.
Context and Source
- Open access Paper: Vasomechanic treatment is associated with increased efflux of human brain proteins
- Institution: Oulu Functional Neuroimaging, University of Oulu and Oulu University Hospital, with collaborators at Lund University, University of Eastern Finland and Kuopio University Hospital, University of Rochester, and University of Copenhagen (Maiken Nedergaard’s group)
- Country: Finland (lead), with Sweden, USA and Denmark
- Journal: Nature Communications
- Impact evaluation: The impact score of this journal is 18.1, evaluated against a typical high-end range of 0-60+ for top general science, therefore this is a High impact journal.
Related Reading:
- Vibrating mattress helps clear Alzheimer’s protein from the brain (New Scientist)
- My Dementia Avoidance Protocol - Please improve it and offer advice
- Predicting and Preventing Alzheimers & Dementia (and minimizing risk)
- How the Collapse of Nitric Oxide Signaling Accelerates Aging
- Broken Vessels: How Sugar, Insulin, and a Rogue Glycoprotein Starve the Heart of Protective Nitric Oxide