The cause of high blood pressure may lie within the brain,
rather than with problems relating to the heart, kidneys or blood
vessels, research suggests.
Scientists at Bristol University say the findings could lead to new
ways of treating the condition, which affects about one in five
Britons.
The scientists isolated a protein, JAM-1, which appeared to trap
white blood cells, obstructing blood flow.
This can cause inflammation and result in poor oxygen supply to the
brain.
Brain blood pressure
Professor Julian Paton and colleagues believe these, in turn,
trigger events that raise blood pressure, the journal Hypertension
reports.
Their studies in rats show JAM-1 is linked to raised blood
pressure, but the exact mechanisms behind this are still unclear.
They are now looking at the human brain to understand more.
Professor Paton explained: "The future challenge will be to
understand the type of inflammation within the vessels in the
brain, so that we know what drug to use, and how to target
them.
"JAM-1 could provide us with new clues as to how to deal with this
disease.
"We are looking at the possibility of treating those patients that
fail to respond to conventional therapy for hypertension with drugs
that reduce blood vessel inflammation and increase blood flow
within the brain."
Drug target
Professor Jeremy Pearson of the British Heart Foundation, which
funded the latest work, said: "This exciting study is important
because it suggests there are unexpected causes of high blood
pressure related to blood supply to the brain.
"It therefore opens up the possibility of new ways to treat this
common, but often poorly managed, condition."
It has been known for some time that the brain can affect blood
pressure.
A team of researchers, led by Neurosurgery expert Mr Alex Green of
Oxford's John Radcliffe Hospital, found they could make patients'
blood pressure increase or decrease by stimulating very specific
regions of the brain with electrodes.
Mr Green said the latest work was "very exciting" and that it
suggested JAM-1 could be a good target for new blood pressure
therapies.
Professor Graham MacGregor, chairman of the Blood Pressure
Association, cautioned that the work was at a very early stage and
much more extensive research was needed.
He said blood pressure medicines currently prescribed by doctors
could be very effective, provided they were taken correctly and in
combination with leading a healthy lifestyle.
Although high blood pressure, also known as hypertension, can cause
headaches, dizziness and problems with vision, the majority of
people with the condition do not display any noticeable
symptoms.
It can lead to heart attack, stroke and kidney damage, but
medication can be used to control its effects if changes to
lifestyle fail to lower blood pressure.
From BBC news