SYDNEY — Scientists in Australia, home to some of the most poisonous creatures on Earth, have made a discovery about spider venom that they hope could lead to a new class of drugs to help heart attack victims.

Spiders use their venom to immobilize or kill their prey. Researchers from the University of Queensland and Sydney’s Victor Chang Cardiac Research Institute are working on a potential drug candidate derived from spider venom that blocks the “death signal” sent from the heart in the wake of a heart attack that causes heart cells to die. There are no drugs in clinical use that prevent the damage caused by heart attacks, the researchers said.

The protein, called Hi1a, originally identified in the venom of the Fraser Island funnel-web spider, could also eventually be used to treat donor hearts, increasing how far they can be transported and improving the likelihood of a successful transplant, the researchers said. The study was published recently in the journal Circulation.

“This will not only help the hundreds of thousands of people who have a heart attack every year around the world, it could also increase the number and quality of donor hearts, which will give hope to those waiting on the transplant list,” said Peter Macdonald, a professor at the Victor Chang Cardiac Research Institute who is one of the study’s authors.

“Usually, if the donor heart has stopped beating for more than 30 minutes before retrieval, the heart can’t be used,” Macdonald said. “Even if we can buy an extra 10 minutes, that could make the difference between someone having a heart and someone missing out. For people who are literally on death’s door, this could be life-changing.”

Spiders aren’t the only venomous creatures being studied for medical purposes. A diagnostic drug in development uses the potent venom of the Israeli deathstalker scorpion and an infrared dye to seek out and illuminate tumors. The drug has gone through safety testing and early clinical trials to view brain tumors in children.

Funnel-webs are regarded by some scientists to be one of the most dangerous spiders in the world. Their fangs are large, powerful and capable of penetrating fingernails and soft shoes.

The Australian heart research is in its early stages; the researchers have tested the drug candidate on beating human heart cells exposed to heart attack stresses to see whether the drug improved their survival, and they are aiming to begin human clinical trials in the next two or three years.

Cardiovascular diseases are the leading cause of death globally, taking an estimated 17.9 million lives each year, according to the World Health Organization. More than four out of five cardiovascular deaths are due to heart attacks and strokes, and a third of these deaths occur in people under 70 years of age, the WHO says.

The Australian discovery builds on earlier work by Glenn King, a professor at the University of Queensland, who identified a small protein in the venom of the same funnel-web spider that was shown to markedly improve recovery from stroke.

After a heart attack, blood flow to the heart is reduced, resulting in a lack of oxygen to the heart muscle. This causes the cell environment to become acidic, triggering a message for the heart cells to die.

“Despite decades of research, no one has been able to develop a drug that stops this death signal in heart cells, which is one of the reasons why heart disease continues to be the leading cause of death in the world,” said Nathan Palpant, one of the study’s co-authors, who is also from the University of Queensland.

Toby Passioura, who works in peptide drug discovery at the University of Sydney and wasn’t involved in the study, said it shows “a lot of promise,” especially because a lot of medical injuries — including strokes and heart attacks — occur as a result of a sudden loss of oxygen.

“It seems to work quite a long time after the injury as well, which is important if you’re thinking about someone who has had a heart attack or a stroke,” he said. “It’s exciting stuff.”

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