Brain’s ‘Natural Pump’ Reveals New Clues to Alzheimer’s and Aging
A groundbreaking new brain imaging technique is offering unprecedented insight into the health of the brain’s smallest blood vessels, potentially unlocking new avenues for early diagnosis and treatment of Alzheimer’s disease and age-related cognitive decline.
Scientists at the Mark and Mary Stevens Neuroimaging and Informatics Institute (Stevens INI) at the Keck School of Medicine of USC have developed a noninvasive method to measure microvascular volumetric pulsatility – the rhythmic swelling and shrinking of tiny blood vessels – in living humans. Published recently in Nature Cardiovascular Research, the study reveals that these subtle pulsations strengthen with age and may play a critical role in the progression of neurodegenerative diseases.
The research team utilized ultra-high field 7T magnetic resonance imaging (MRI) to observe these previously unseen movements. They discovered that the pulses are particularly pronounced in the brain’s deep white matter, a region vital for communication between brain networks but also susceptible to reduced blood flow. As these pulsations intensify, they may disrupt brain function and contribute to memory loss and the development of Alzheimer’s.
“Arterial pulsation is like the brain’s natural pump, helping to move fluids and clear waste,” explained a senior researcher involved in the study. “Our new method allows us to see, for the first time in people, how the volumes of those tiny blood vessels change with aging and vascular risk factors. This opens new avenues for studying brain health, dementia, and small vessel disease.”
For years, scientists have understood the link between stiffening and excessive pulsation in larger arteries and conditions like stroke and dementia. However, observing these rhythmic changes in the brain’s microvasculature required invasive procedures previously limited to animal studies. The USC team overcame this hurdle by combining two advanced MRI techniques – vascular space occupancy (VASO) and arterial spin labeling (ASL) – to monitor subtle shifts in microvessel volume throughout the cardiac cycle.
The results showed that older adults exhibit stronger microvascular pulsations in deep white matter compared to younger individuals, and that hypertension further exacerbates this effect. “These findings provide a missing link between what we see in large vessel imaging and the microvascular damage we observe in aging and Alzheimer’s disease,” stated the study’s lead author.
Furthermore, excessive vascular pulsation may interfere with the brain’s glymphatic system, a recently discovered waste-removal network. This system clears harmful substances like beta-amyloid, a protein that accumulates in the brains of Alzheimer’s patients. Disruption of this fluid circulation could accelerate cognitive decline.
“Being able to measure these tiny vascular pulses in vivo is a critical step forward,” said the director of the Stevens INI. “This technology not only advances our understanding of brain aging but also holds promise for early diagnosis and monitoring of neurodegenerative disorders.”
Researchers are now working to adapt the method for use with more widely available 3T MRI scanners. Future studies will investigate whether microvascular volumetric pulsatility can predict cognitive outcomes and serve as a biomarker for early intervention in Alzheimer’s disease and related conditions.
“This is just the beginning,” a senior author noted. “Our goal is to bring this from research labs into clinical practice, where it could guide diagnosis, prevention, and treatment strategies for millions at risk of dementia.”
The study was authored by Fanhua Guo, Chenyang Zhao, Qinyang Shou, Kay Jann, and Xingfeng Shao from the Stevens INI, alongside Ning Jin from Siemens Healthcare, and led by Danny JJ Wang. The research received support from the National Institutes of Health (NIH) grants UF1-NS100614, S10-OD025312, R01-600 NS114382, R01-EB032169, RF1AG084072, R01-EB028297, R01-NS134712, and R01-NS121040.
