Friday, 12 October 2018

Tiny Nanoparticles to Treat a Huge


Tiny Nanoparticles to Treat a Huge Problem: Snakebites An Epi-Pen to treat a snakebite?

It’s still a foreign dream, but a Californian chemist and Costa Rican venom expert is
reporting progress during a novel effort to form injectable nanoparticles which will neutralize
snake venom and can be carried in backpacks.

In a recent study in PLOS Neglected Tropical Diseases, their particles protected mice against
tissue damage from spitting-cobra venom without triggering allergies.
In wealthy countries, snakes are an abiding threat to an unlucky few, among them hikers,
ranch hands, soldiers, zookeepers and reptile collectors.

In the tropics of Africa, Asia, and Latin America, however, they're a serious explanation for death
and disability in rural areas: quite 2 million people are bitten annually. About 100,000
of them die, and another 400,000 are left with serious disabilities, including amputations or
nerve damage so extensive that a leg or hand is permanently useless.

Snakebite research has been slim, compared to the scope of the threat — and sometimes
controversial. Old first-aid maxims — like slitting open the wound and sucking out the
venom — are now discredited.

There are reports of electrical shocks, including stun guns, wont to break down the
poisons. But most reports are anecdotal, and there's no accepted explanation about how
they work — if they work.

Antivenins have existed for many years, of course, but they're expensive, potentially
dangerous and used only rarely in poor countries. The medicines contain antibodies
harvested from the blood of sheep or horses that are injected with diluted venom
and allowed to recover.

The process is cumbersome, and therefore the antibodies must be kept refrigerated. Few drug
companies bother to form antivenins, therefore the prices are high.

Because they contain horse or sheep proteins, antivenins can also, trigger life-threatening
anaphylactic shock or hemorrhaging. They must be given intravenously in an emergency
room and lots of bite victims die before they will reach hospitals.

Moreover, anti-venoms are very species-specific: a treatment for cobra bites, for instance,
will not help against rattlesnake or asp bites. Hospitals must keep many kinds of antivenins
on hand, and victims must be ready to produce or describe the snake that bit them.

“They have tons of issues, but they’re the sole show in town,” said Kenneth J. Shea, a chemist
at the University of California, Irvine.

Dr. Shea’s lab is creating hydrogel nanoparticles coated with polymers — the building blocks
of plastics — sufficiently small to connect to proteins.

While screening them against common venoms, he isolated some nanoparticles that bind
with and neutralize two poisons produced by snakes like cobras, kraits, coral snakes, sea
snakes and mambas.

José María Gutiérrez, a venom specialist at the University of Costa Rica, injected dozens of
mice with the venom of the black-necked black-necked cobra. He found that Dr. Shea’s
nanoparticles significantly reduced tissue damage in the mice. Importantly, the nanoparticles didn't appear to interfere with normal proteins or to trigger dangerous allergic reactions.

Much more research needs to be done, Dr. Shea said, but the goal is to make a cocktail of
particles that would be loaded in an injector like an Epi-Pen.

It would not completely replace antivenins. But since the nanoparticles are relatively easy to
make and wish no refrigeration, they might be carried within the field and injected into the location
of a bite, reducing tissue damage and stopping the poison from spreading. That would buy
time to reach better treatment.

Asked about the source of his funding, Dr. Shea said, “Well, immediately I don’t have any
money for this.”The military expressed initial interest, he said, then has the veterinary industry. But he also hopes to draw in the eye of groups that fund global health research, just like the Bill
and Melinda Gates Foundation or the Wellcome Trust.

The path to regulatory acceptance could also be an extended one. The use of nanoparticles in medicine is relatively new, and for clinical trials involving snakebites, “there aren’t many volunteers,” Dr. Shea said.

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