SCIENTISTS have made a world-first breakthrough which could change the treatment of dementia.
New research, led by experts at University College London, is the first to identify blood flow sensors within the brain.
The groundbreaking study, published in the journal Nature Communications, could help find new treatments for conditions including dementia, high blood pressure and migraines.
For decades, scientists have suspected that the brain had a way of monitoring and regulating its own blood flow separate from the body-wide blood pressure control system.
But experts had been unable to prove this – until now.
The team, who collaborated with the University of Auckland and Bristol University, discovered a new function of tiny star-shaped brain cells, known as astrocytes.
These cells function as specialised brain blood flow sensors that operate to self-protect the brain from potentially damaging reductions in blood supply.
Astrocytes are strategically positioned between the brain blood vessels and important nerve cells, which control the heart and circulation – ultimately determining the arterial blood pressure.
In the lab-based study in rats, the researchers found that decreases in brain blood flow caused astrocytes to release a chemical signal.
This stimulated the specialised nerve cells to increase blood pressure and restore blood flow to the brain.
UCL Professor Alexander Gourine, who led the study, said: “There has never been a formal description of a blood flow or blood pressure sensor within the brain before.
“Our new data identify astrocytes as brain blood flow sensors that are critically important for setting the level of systemic blood pressure and in doing so ensure that the brain receives a sufficient amount of oxygen and nutrients to support the uninterrupted operation of the information processing machinery.”
Co-author Professor Julian Paton, from the University of Auckland, said: “These astrocyte cells are exquisitely sensitive to reductions in brain blood flow.
“When blood supply is reduced, they release a chemical signal to nearby nerve cells that raise blood pressure, restoring blood flow to the brain.
“What we have discovered is that the brain has an automatic way to make sure that brain blood flow is preserved.
“Unfortunately, in pathological conditions this is happening at the expense of generating higher blood pressure in the rest of the body.
“This suggests that increasing brain blood flow by reducing activity in these blood flow sensing astrocytes may be a way to lower blood pressure in people with hypertension.
“It may also be a way to combat migraines and strokes. On the other hand, sensitising these cells may help in conditions of dementia to improve brain blood flow.”
Corresponding author, Dr Nephtali Marina-Gonzalez, from UCL, said: “In disease situations where blood supply to the brain is reduced, the mechanisms we describe can over-react causing migraines, high blood pressure and strokes.
“The identity of the brain blood flow sensor will make it possible to search for novel targeted treatment strategies to alleviate these diseases”.