Looking For Lag As A Brain Aging Biomarker

Using MRI to measure a time lag between two blood drainage systems in the brain could be a quick and easy way to diagnose brain aging, researchers say.

AsianScientist (Jun. 8, 2020) – In a study published in Brain, researchers at the RIKEN Center for Biosystems Dynamics Research, Japan, describe a new biomarker of brain aging that can be easily detected with magnetic resonance imaging (MRI).

As we age, certain people experience ventriculomegaly, the enlargement of the ventricles of the brain caused by the accumulation of fluid. Although ventricular enlargement within normal range is not itself considered a disease, when left unchecked it can lead to ventriculomegaly and dementia.

In the present study, a team led by Dr. Toshihiko Aso has found that a lag time between two blood drainage pathways in the brain precedes the development of ventriculomegaly and could be used as a biomarker of brain aging. This lag can be detected easily with MRI, making it a potential biomarker for predicting ventriculomegaly and the aging brain, which can then be treated quickly.

After blood circulates through the brain providing necessary oxygen, the deoxygenated blood must return to the heart though our veins. This happens through two pathways, one draining blood from regions close to the surface of the brain, and the other from areas deep in the brain. By using MRI to measure changes in blood flow, the team found that the time it takes for blood to drain through these two pathways becomes out of sync as we age. The result is a time lag between the deep drainage pathway and the surface pathway, which grows at almost the same rate as enlarging ventricles, but begins slightly earlier.

“We found an age-related perfusion timing shift in the brain’s venous systems whose lifespan profile was very similar to, but slightly preceded that of ventricular enlargement,” explained study first author Toshihiko Aso.

They also examined people with traumatic brain injury because these individuals often suffer from enlarged ventricles and have brains that appear to have aged prematurely. Their analysis showed a time lag in blood drainage that was related to the disease, but this effect depended on the age at injury, being large in people who suffered traumatic brain injury when they were young, but much less for those who were injured later in life.

“The timing asynchrony between deep and superficial venous drainage might therefore be a common mechanism that underlies both types of ventriculomegaly,” said Aso. “This new biomarker might therefore be useful for diagnosing and monitoring normal-pressure hydrocephalus that is either age-related or that results from brain injury.”

Because dementia resulting from hydrocephalus can be reversed by removing the fluid that builds up in the ventricles, early diagnosis is critical. To aid early diagnosis, the researchers are already developing non-invasive applications of this technology.

“We hope that using this biomarker to monitor the aging brain becomes a part of the annual health checkup system for people in Japan.”

The article can be found at: Aso et al. (2020) A Venous Mechanism of Ventriculomegaly Shared Between Traumatic Brain Injury and Normal Aging.


Source: RIKEN; Photo: Shutterstock.
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