Venom-Based Treatments Gain Popularity


Image: Extracting snake venom.
Photo Credit: Wikipedia

Do you know someone with diabetes, heart disease, hypertension, or cancer? Then you know the misery and death these diseases cause. Who knew the remedy for such diseases might lie in toxins from the venom of Gila monsters, snakes, scorpions, or cone snails? The “molecular gifts” of these animals can kill; but, in these cases, their poisons have already produced powerful medicines to treat diseases and hold promise for treatments and cures in the future.

Cone snail venom, a thousand times deadlier to humans than cyanide, has the potential to treat seizures and mask pain for people with late-stage cancer. The venom in these snails contains peptides, short strings of amino acids similar to proteins, known as conantokins. The specific target of these peptides may prove instrumental in treating seizures and cancer. Conantokins can also protect people from Alzheimer's Disease, Parkinson's Disease, depression, and nicotine addiction. Ziconotide, a morphine-like drug with a structure identical to the conantokins, has already passed human trials. Four more compounds are currently being tested.

In 1992, endocrinologist John Eng first discovered a key component in the venom of Gila monsters' saliva that could change the lives of the 25 million people suffering from type 2 diabetes. This component was responsible not only for reducing appetite but also for controlling blood sugar. Exenatide, a drug derived from the Gila’s saliva venom, acts as a catalyst for cells. Normally in type 2 diabetes, cells ignore insulin’s signals to take in excess sugar. Exenatide tells the cells to deal with excess sugar in the blood but remain inactive when blood sugar levels are in the normal range. Eventually, it even helps people with diabetes lose weight.

The venom of another snake, the Eastern green mamba, may be beneficial to these with heat problems. This venom contains a peptide that, when fused with another peptide in the lining of human blood cells, creates the drug Cenderitide. This drug, which is still in clinical trials, was created by researchers at the Mayo Clinic to lower blood pressure and reduce fibrosis, an excessive amount of connective tissue growth in the heart. It was also created to act as a protective barrier between the kidney and large amounts of salts and water. If clinical trials on humans go well, this drug could significantly improve the quality of life for those suffering heart issues.

Image: Deathstalker Scorpion
Photo Credit: Wikimedia

Reptiles are not the only helpful venomous animals. Arthropods are stepping up as well, including the giant death stalker scorpion. This scorpion contains a neurotoxin in its venom that can attach to the surface of brain cancer cells. An MRI, although helpful and an important part of the diagnostic process, can only detect tumors larger than a billion cells. This puts surgeons in a tough spot. They have to estimate the boundaries between the tumors and healthy tissue based on visual and textural clues. By mixing this neurotoxin, a chlorotoxin, with a near-infrared dye, doctors were able to create a “molecular flashlight” or, in other words, a “tumor paint” that could be used to distinguish cancer cells, effectively. The modified near-infrared dye can color smaller cell clusters, sometimes comprised of as few as 200 cells. This greatly increases the diagnostic capabilities of the process and improves the treatment prospects for patients with glioma, the most common type of brain cancer. In the future, the new dye could also be used to diagnose prostate, colon, lung, breast, pancreatic, and skin cancers.

Venom-based cures are not a new idea. Their history can be traced back to Sanskrit texts from the second century B.C.E. What is new, however, is the amount of knowledge and technology currently available that allows scientists to study and classify venoms in a faster, more efficient way. Each new technological breakthrough accelerates the process of discovering cures for a multitude of life-threatening diseases.

[Source: National Geographic]

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