Researchers Discover Brain Blood Flow Sensor Which Could Lead To New Treatments For Hypertension And Dementia
Source : Thailand Medical News Jan 16, 2020 4 years, 10 months, 1 week, 38 minutes ago
Medical researchers from University College London (UCL) have discovered the mechanism that allows the
brain to monitor its own
blood supply, a finding in rats which may help to find new treatments for human conditions including
hypertension (
high blood pressure) and
dementia.
For many years, 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 until now no one had proven this.
The human
brain needs more
blood than any other organ to satisfy neurons' relentless, high demand for oxygen, so it makes sense that it would have a way of buffering itself from
blood flow fluctuations in the wider body. Disturbances to
brain blood flow are a known cause in many diseases, for example, sustained reduction in
brain blood flow is a likely cause of cognitive decline,
dementia, and neurodegenerative disease such as Alzheimer's disease.
The study published in
Nature Communications, indicated that researchers from UCL, the University of Auckland and Bristol University, found a new function for the star-shaped
brain glial 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.
The
astrocytes are strategically positioned between the
brain blood vessels and important nerve cells, which control the heart and peripheral circulation, ultimately determining the arterial
blood pressure.
The researchers found that decreases in
brain blood flow caused
astrocytes to release a chemical signal, which stimulated the specialised nerve cells to increase
blood pressure and restore/maintain
blood flow (and oxygen supply) to the
brain.
Dr Alexander Gourine, a Professor at UCL Division of Biosciences, who led the study told
Thailand Medical News, "We are very excited about this observation: 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 (arterial)
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."
Professor Julian Paton, (
University of Auckland), coauthor added, "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.”
Professor Paton further added, "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."
Dr. Nephtali Marina-Gonzalez, corresponding author from UCL Division of Medicine, commented, "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."
Reference: Nephtali Marina et al, Astrocytes monitor cerebral perfusion and control systemic circulation to maintain brain blood flow, Nature Communications (2020). DOI: 10.1038/s41467-019-13956-y 
