Capillary blood vessels in the body are not
hermetically sealed and chemicals in the
blood can leak out into the surrounding tissue
(and vice versa).
This is not the case in the brain, where
such general leakage would disrupt message
transmission. There is thus a blood-brain
barrier where capillary cell walls are more
tightly joined together.
There is some transmission through the walls, though this
is carefully managed and the walls are selectively permeable. If nothing from the blood could escape,
then it would serve no purpose. For example
glucose transporters that bring fuel for
the brain are allowed through.
The blood-brain barrier is also weaker in
the area postrema in the medulla, where vomiting is managed.
In this way toxins in the blood can be monitored
and the vomit reaction triggered as needed.
Parts of the brain, Hindbrain
(Please click the red arrow to full text
The Blood-Brain Barrier - Treatment's
The blood-brain barrier stands in the way
of new drug development.
You may have heard of "antisense"
technology, that so-called ultimate magic
bullet of genetic science that promises to
bind to disease-causing strands of messenger
RNA and stop them dead in their tracks. Try
to imagine antisense turned loose inside
your skull, and now imagine kissing your
depression or mania goodbye forever.
The catch? There are probably many, but the
most obvious one is that any drug which targets
any part of the brain must first cross the
blood brain barrier (BBB). The name conjures
up a kind of cross between the Berlin Wall
and a coffee filter, but in fact refers to
nearly 400 miles of narrow capillaries throughout
the brain, all filled with tightly-packed
endothelial cells that are exceedingly selective
in what gets through. Endothelial cells are
also present in capillaries in the body,
but the spacing there poses no difficulty.
The BBB is to protecting the brain internally
as the skull is to protecting it externally.
The problem is the BBB does not differentiate
what it keeps out. Life-saving chemicals,
if they happen to be the wrong chemicals,
simply won't get through. With very few
exceptions, only small molecules soluble
in fat clear the barrier. Alcohol, caffeine,
and nicotine - all meeting this criteria
- have a free pass. So do antidepressants.
The problem is, according to William Pardridge
MD of UCLA writing in the Jan Archives of
Neurology, "small molecules are largely
palliative medicines with often unfavorable
safety profiles." There are no chronic
diseases, other than infectious diseases,
that are cured by small-molecule drug therapy.
Large-molecule drugs have the potential to
cure patients with neurological disorders,
he notes, but none of them can cross the
blood brain barrier. The following paragraph
is worth quoting in full:
"Despite the importance of the BBB to
neuropathic agents, this area is underdeveloped
in the neurosciences. To my knowledge, no
pharmaceutical company in the world has a
BBB drug delivery program! It is not unusual
for an entire conference to be convened on
a given neurologic disorder (eg brain tumors),
with no discussion of targeting drugs through
The blood brain barrier makes certain exceptions
for allowing passage to large molecules and
water-soluble molecules, and exploiting these
exceptions is the key to developing new classes
of drugs. One binding and transport system
in the BBB, for example, permits water-soluble
glucose into the brain and another mediates
the bidirectional movement of large molecule
peptides. According to Dr Partridge: "Based
on the knowledge that these endogenous transport
systems exist, drugs may be reformulated
to enable transport into the brain via the
endogenous BBB transporters."
A lab-made "chimeric peptide",
for example, is half drug (which does not
cross the BBB), and half "molecular
Trojan Horse" (which does). The Trojan
Horses are genetically-engineered proteins
that have slipped through the BBB in lab
Trojan Horses are also being constructed
to slip through concealed genetic material.
New Scientist reports that Dr Partridge and
his team have been working on encasing genes
in fatty spheres called liposomes, which
are coated with a special polymer, to which
certain antibodies are attached. The antibodies
trick the brain-capillary receptors
(Please click the red arrow to text and source
The Blood Brain Barrier (the BBB)
- The brain receives a constant 50ml of blood
per 100g of brain tissue, per minute, no
matter what the conditions. This is unlike
the skeletal muscles or other organs, which
have different blood flow requirements depending
on how they are being used.
- The circle of Willis works to distribute blood at an even pressure,
even if one of the major arteries to the
brain becomes occluded
- With all of this blood coming in, what protects
the brain from blood-borne drugs or other
substances? The blood-brain barrier
- The "barrier" is actually a series
of tight junctions between the endothelial
cells of the tunica intima. The blood vessels
of the brain are the least permeable of all
vessels due to the intercellular connections
- Astrocytes participate in the barrier too.
They cover the capillaries, and their "feet"
help the endothelium to form the tight junctions.
- The barrier is not absolute. Important nutrients such as glucose,
amino acids and certain electrolytes move
easily via facilitated diffusion. Wastes,
such as urea and large proteins, drugs and
other molecules cannot get through to the
- The barrier is not effective against smaller
molecules, including fats, fatty acids, oxygen,
carbon dioxide, alcohol (ethanol) and nicotine.
(Please click the red arrow to text and source)
The Blood-Brain Barrier
The second effect that I want to focus on,
which has been proven in the laboratory,
should by itself have been enough to shut
down this industry and should be enough to
scare away anyone from ever using a cell
phone again. I call it the “smoking
gun” of cell phone experiments. Like
most biological effects of microwave radiation,
this has nothing to do with heating.
The brain is protected by tight junctions
between adjacent cells of capillary walls,
the so-called blood-brain barrier, which,
like a border patrol, lets nutrients pass
through from the blood to the brain, but
keeps toxic substances out. Since 1988, researchers
in the laboratory of a Swedish neurosurgeon,
Leif Salford, have been running variations on this simple
experiment: they expose young laboratory
rats to either a cell phone or other source
of microwave radiation, and later they sacrifice
the animals and look for albumin in their brain tissue. Albumin is a protein
that is a normal component of blood but that does not normally cross the blood-brain
barrier. The presence of albumin in brain tissue is
always a sign that blood vessels have been
damaged and that the brain has lost some
of its protection.
Here is what these researchers have found,
consistently for 18 years: Microwave radiation, at doses equal to
a cell phone’s emissions, causes albumin
to be found in brain tissue. A one-time exposure
to an ordinary cell phone for just two minutes
causes albumin to leak into the brain. In
one set of experiments, reducing the exposure
level by a factor of 1,000 actually increased
the damage to the blood-brain barrier, showing
that this is not a dose-response effect and that reducing the power will not make
wireless technology safer. And finally, in research published in June
2003, a single two-hour exposure to a cell
phone, just once during its lifetime, permanently damaged the blood-brain barrier and, on autopsy 50 days later, was found
to have damaged or destroyed up to 2 percent
of an animal’s brain cells, including
cells in areas of the brain concerned with
learning, memory and movement.1 Reducing
the exposure level by a factor of 10 or 100,
thereby duplicating the effect of wearing
a headset, moving a cell phone further from
your body, or standing next to somebody else’s
phone, did not appreciably change the results!
Even at the lowest exposure, half the animals
had a moderate to high number of damaged
The implications for us? Two minutes on a cell phone disrupts the blood-brain
barrier, two hours on a cell phone causes permanent brain damage, and secondhand radiation may be almost
as bad. The blood-brain barrier is the same
in a rat and a human being.
These results caused enough of a commotion
in Europe that in November 2003 a conference
was held, sponsored by the European Union,
titled “The Blood-Brain Barrier —
Can It Be Influenced by RF [radio frequency]-Field
Interactions?” as if to reassure the
public: “See, we are doing something
about this.” But, predictably, nothing
was done about it, as nothing has been done
about it for 30 years.
America’s Allan Frey, during the 1970s, was the first of many
to demonstrate that low-level microwave radiation
damages the blood-brain barrier.2 Similar
mechanisms protect the eye (the blood-vitreous
barrier) and the fetus (the placental barrier),
and the work of Frey and others indicates
that microwave radiation damages those barriers
also.3 The implication: No pregnant woman
should ever be using a cell phone.
Dr. Salford is quite outspoken about his
work. He has called the use of handheld cell phones
“the largest human biological experiment
ever.” And he has publicly warned that a whole generation
of cell-phone-using teenagers may suffer
from mental deficits or Alzheimer’s disease by the time they reach middle age.
Unfortunately, cell phone users are not the
only ones being injured, nor should we be
worried only about the brain. The following
brief summary is distilled from a vast scientific
literature on the effects of radio waves
(a larger spectrum which includes microwaves),
together with the experiences of scientists
and doctors all over the world with whom
I am in contact.
Organs that have been shown to be especially
susceptible to radio waves include the lungs,
nervous system, heart, eyes, testes and thyroid
gland. Diseases that have increased remarkably
in the last couple of decades, and that there
is good reason to connect....
(Please click the red arrow to full text