Study: Sting's venom hid fat-fighting secret


Study: Sting’s venom hid fat-fighting secret

A mouse made chubby on a high-fat diet, left, stands next to a mouse that lost weight after being treated with a drug derived from sea anemone venom.

A drug derived from sea anemone venom can make fat mice thin – with potentially powerful implications for treating obesity and diabetes in humans.

The compound, called ShK-186, not only reduced weight, but cholesterol and blood sugar as well. What's more, the drug had no effect on regular mice fed a normal diet – suggesting its effects are only triggered in mice on an obesity-inducing diet.

The discovery was recently published by a UC Irvine team, whose work has been leading up to it for 30 years; human trials of the drug's effects on obesity could begin in a few years.

"This is a drug that both affects fat metabolism and diabetes," said George Chandy, a UC Irvine physiology and biophysics professor who led the team. "There aren't any drugs that do both."

How Chandy and his science team found their way to the discovery is at least as interesting as the discovery itself.

Chandy and a colleague, Michael Cahalan, began their journey in 1984 when they traced out a molecular pathway shared by immune cells that cause multiple sclerosis, diabetes and rheumatoid arthritis.

The pathway, in fact, is a kind of superhighway for immune cells run amok. A protein called the Kv 1.3 potassium channel, which is found on the surface of one class of immune cells, allows the cells to attack.

They attack the brain, along with a nerve-insulator known as myelin, in MS patients, the pancreas in children with type 1 diabetes and the joints of rheumatoid arthritis sufferers.

The next link in the chain came in the 1990s. That was when the potentially beneficial effects from nasty stings first caught the attention of Chandy's team.

According to reports in the press and the medical literature, stings from anemones and scorpions sometimes had an astonishing effect on people with multiple sclerosis.

"One doctor from England said he had very severe MS," Chandy said. "He's taken to the Bahamas, gets into the water and is stung by a sea anemone. He comes out with his whole back full of rash, terrible pain – then, 48 hours later, surprise! This guy who could not walk could now run a mile."

Another case involved a woman with severe MS who was stung by a scorpion while vacationing in Arizona, according to a study published in the early 1980s. Her MS symptoms vanished for eight to 10 weeks.

In most cases, the effects wore off after a few weeks, though often leaving the patient with less-severe symptoms.

"We started wondering, 'What is in venoms that can do this?'" Chandy said. "Venoms are known to paralyze people, and the way they do this is by blocking channel proteins."

They began trying to find out if the venom might, just possibly, block the pathway they discovered in 1984.

"We started playing around with scorpion toxins," he said. "We found one that blocked Kv 1.3."

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