“Higher Blood Pressure May
Lead to Brain Shrinkage” It is clear that hardening of
the arteries inside our brain and cognitive decline
travel hand in hand, something I’ve
addressed before. However, the independent
association of Alzheimer’s with multiple atherosclerotic
vascular disease risk factors suggests that cholesterol is not
the sole culprit in dementia. One of the most
consistent findings is elevated levels of blood
pressure in midlife, meaning ages 40 through 60,
is associated with elevated risk of cognitive impairment and
Alzheimer’s dementia later in life. In fact, even more so than having
the so-called Alzheimer’s gene. The normal arterial tree, all
the blood vessels in the brain, is designed as both
a conduit and cushion. But, when the artery
walls become stiffened, every time our heart pumps
blood up into our brain, the pressure from the pulse can
damage small vessels in our brains. This can cause what are called
microbleeds in our brain, which are frequently found in
people with high blood pressure, even if they were never
diagnosed with a stroke. These microbleeds may be one
of the important factors that cause cognitive impairments,
perhaps not surprisingly, because on autopsy,
microbleeds may be associated with brain tissue necrosis,
meaning brain tissue death. And, speaking of tissue death, high
blood pressure is also associated with so-called lacunar infarcts, from the Latin word
lacuna, meaning hole. These are holes in
our brain that appear when little arteries get
clogged in our brain and result in the death of
a little round region of the brain. Up to a quarter of the elderly
have these little ministrokes, and most don’t even know it,
so-called silent infarcts, but no black holes in
the brain are benign. This is what they
look like— it’s like your brain
has been hole-punched. Although silent infarcts,
by definition, lack overt stroke-like symptoms, they are associated with
subtle deficits in physical and cognitive function
that commonly go unnoticed. And, they can double
the risk of dementia. That’s one of the ways high blood
pressure is linked to dementia. So much damage that high
blood pressure levels can lead to brain volume reduction,
literally a shrinkage of our brain, specifically in the hippocampus,
the memory center of the brain. This helps explain how
high blood pressure can be involved in the development
of Alzheimer’s disease. One can actually visualize the little
arteries in the back of our eyes, using an ophthalmoscope,
providing a noninvasive window to study the health of one’s
intracranial arteries, the little vessels
inside our head. The researchers found a
significant association between arterial disease and
brain shrinkage on MRI. But, this was a cross-sectional study,
just a snapshot in time; so, you can’t prove
cause and effect. What you need is a prospective
study, following people over time; and so, that’s what they did. Over a 10 year period, those
with signs of arterial disease were twice as likely to
suffer a significant loss of brain tissue
volume over time. Video source: https://www.youtube.com/watch?v=HspIdIpuARs
