In order to combat ageing and age-related diseases, we need to identify and understand the markers of biological age. The processes that underlie ageing occur at different rates in different people and different tissues, and recognising the signs of biological age within an organ is the first step towards slowing or reversing the ageing process.
Here, researchers report that age-related changes in cerebral blood flow may serve as a useful biomarker for the ageing brain, and could be used as a predictor for, a treatable condition that can lead to dementia if left unchecked.
Ventriculomegaly is an abnormal condition in which fluid accumulates in the ventricles of the brain without properly draining, making them enlarged. Although ventricular enlargement within normal range is not itself considered a disease, when left unchecked it can lead to ventriculomegaly and dementia resulting from normal pressure hydrocephalus. In their study, the team found that ventriculomegaly was associated with changes in blood circulation of the brain. “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,” explains first author Toshihiko Aso.
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 at BDR recently found that as we age, the time it takes for blood to drain through these two pathways becomes out of sync. The result is a time lag between the deep drainage pathway and the surface pathway, which increases with age.
Because dementia resulting from hydrocephalus can be reversed by removing the fluid that builds up in the ventricles, early diagnosis is critical and the researchers at BDR 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.”