Monday, November 8, 2010

5 Medicinal Uses for Common Animal Venoms

Whether you're talking about Spider-man's archenemy or the deadly poisons that animals and insects use to kill their prey, venom most often conjures up negative thoughts. Spider bites, snakebites, bee stings: All of these frighten us, and it's not only about the pain of getting bitten, but also the potentially harmful toxins. But as it turns out, some venoms may be actually be beneficial to human health. Venoms contain hundreds of different ingredients, some of which are not the harmful toxins we assume them to be. Venoms are extremely biologically active and these chemical concoctions provide a great natural resource for researchers to study different chemicals, some of which can be developed into drugs. From scorpions and spiders to snakes and bees, many other researchers are finding ways to bring out the positive in poison. Here's a look at five recent examples of venom as medicine.

Deathstalker Scorpion Venom for Brain Cancer



Deathstalker Scorpion, Leiurus Quinquestriatus (Photo by Furryscaly/Flickr)

The deathstalker scorpion, native to North Africa and the Middle East, is highly dangerous because of its venom—a neurotoxin powerful enough to kill a child or elderly person, often by causing pulmonary edema.

Recently, Miqin Zhang, a materials scientist at the University of Washington, and her research team showed that a certain compound found in the venom of the deathstalker scorpion could help in the treatment of brain cancer.

In a study published in the monthly journal ACS Nano, Zhang showed off a way to use an ingredient of the venom called chlorotoxin (which, despite its name, is nontoxic) to help treat brain cancer. In gene therapy, doctors inject small bits of healthy DNA that are attached to nanoparticles, and these move toward the tumor site to repair or replace the cancer-causing gene mutations.

The problem is that many of the substances currently used for delivery either don't deliver the genes efficiently or have potentially harmful side effects. But by attaching chlorotoxin to the nanoparticle, Zhang and her research team managed to get significantly more of the therapeutic DNA sequence into the cancerous cells than by using nanoparticles without the compound.

Bee Venom in Cancer Treatment



Honey Bee, Apis Mellifera

In a similar study, Samuel A. Wickline, a biomedical engineer at Washington University School of Medicine, altered a protein found in bee venom—which often causes inflammation after stings—called melittin. Like chlorotoxin, melittin can help deliver therapeutic drug compounds to damaged cells. Wickline linked the compound to the membrane of nanoparticles, which, without disrupting a drug's normal function, helped it more accurately hit its target. Scientists are primarily focused on using this as an anticancer therapy.

 

Tarantula Venom for Muscle Dystrophy



Chilean Rose Tarantula, Grammostola Rosea

Frederick Sachs, a biophysicist at the University of Buffalo, studies the function of ion channels on the membranes of muscle cells to see what happens in muscle tissue when you turn these channels on and off. He has been searching for a chemical that would inhibit these channels.

After getting no results from known drug compounds, he and his research team turned to the Chilean rose tarantula, a relatively harmless spider commonly bought in pet stores. In their studies of the venom, which is too weak to harm a human, they came across a peptide that they called GsMtx-4.

Sure enough, the isolated peptide successfully turned the channels off, which Sachs figured could reduce the amount of stress in muscles. Excessive mechanical stress on muscles is common in muscular dystrophy, a disease that can cripple young children. But by injecting a synthetic version of the peptide into lab mice with dystrophy, Sachs found that muscle activity improves. Currently, Sachs and his research team are awaiting FDA approval to begin clinical trials.

Scorpion Venom for Studying Pancreatitis



Brazilian Yellow Scorpion, Tityus Serrulatus

A compound called antarease, similar to the peptide found in tarantula venom, has proved a useful medical tool because of its effect on ion channels. East Carolina's Fletcher discovered the compound in the venom of the Brazilian yellow scorpion, which often causes pancreatitis—a severe inflammation of the pancreas—in sting victims.

Fletcher's research team found that antarease is the likely cause; when they injected the purified compound into pancreatic tissue, it disrupted the pancreas' control of its digestive enzymes, insulin, and other proteins, which can cause inflammation.

Pancreatitis is more commonly caused by gallstones and alcohol abuse, and recent studies suggest it may be a precursor to pancreatic cancer. Fletcher hopes to use his work with scorpion venom and antarease to further understand the pathology of pancreatitis and eventually plan a better treatment for it.

Cobra Venom for Arthritis



Indian Cobra, Naja Naja

The Indian cobra is one of the most common venomous snakes in South East Asia, and is responsible for most of the 10,000 deaths by snakebite that occur in India each year. Despite that danger, India's traditional medicine system, ayurveda, has used these cobra venoms to treat various health conditions for thousands of years. Witch-doctor-esque as that may sound, a recent study may lend validity to the practice.

Earlier this year, physiologist Antony Gomes and his research team at the University of Calcutta in India published a paper in the journal Toxicon showing the role the venom might play in improving arthritis. In the study, male rats were induced with arthritis and were then injected with nonlethal doses of Indian monocellate cobra venom. The rats showed significant improvement in their arthritic symptoms.