An unusual approach and with the natural toxicity toned down it could turn out to be practical.
Thus we may have a useful class of pharmaceuticals that can be delivered to the brain itself.
This was obviously an important problem to solve and a number of protocols are been pursued. Lowering the toxicity may have been the easiest part of the problem and that ring structure is certainly promising
.
Bee venom blasts through blood brain barrier to bring medicine
http://newatlas.com/bee-venom-blood-brain-barrier-drug-delivery/48753/
Getting medication to the brain can be tricky because
of the blood brain barrier, which acts like a semipermeable wall
between the circulatory system and the fluid surrounding the brain to
restrict access to the all-important organ. Certain peptides in animal
venoms are known to bridge that gap in order to attack the brain and new
research hopes to hijack that invasive quality to deliver drugs across
the barrier instead.
We've seen other promising methods of getting through the barrier that involve magnetic nanoparticles and the more natural approach of using bubbles,
but a team of scientists from the Institute for Research in Biomedicine
(IRB) in Barcelona used apamin, a peptide found in the venom of bees
that is known to accumulate in the central nervous system of people who
have been stung.
"We thought that because the venoms of some
animals are able to attack the central nervous system, they should be
able to go through the blood-brain barrier and possibly shuttle drugs
across it," said IRB's Ernest Giralt, Ph.D.
Of course, Giralt's method of using a toxin to
smuggle medication to the brain is a little problematic because of that
little issue of toxicity. Giralt explains that the team set out to
modify apamin to make it less toxic but still able to cross over the
blood brain barrier. This was done by removing the chemicals in apamin
that allow it to attach to a potassium channel in neurons.
"This modification made apamin much less toxic, and its ability to cross the blood brain barrier was intact," Giralt says.
Next, the researchers experimented with making
their modified medicine courier smaller and invisible to the immune
system. The result was a version called Mini-Ap4 that was even better at
accessing the brain than the original peptide.
The researchers concede that other similar drug
delivery methods are in the works that can also cross the barrier, but
they believe the advantage of their technique lies in the fact that
Mini-Ap4 has a ring structure rather than the linear peptides used in
other approaches. The ring shape makes the modified peptide more
resistant to proteases, which are enzymes that break down peptide bonds.
Now that the researchers are confident their
modified peptide can travel where it needs to go, the next steps will
involve seeing how well it does at actually carrying cargo and
delivering medication. The plan is to investigate this using human cells
and in mice.
They'll also be doing additional research to ensure that a person allergic to bees wouldn't have a similar reaction to Mini-Ap4.
The researchers presented their work Sunday at the national meeting of the American Chemical Society.
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