In a preclinical trial on a beating human heart, researchers have found that a drug candidate developed from the venom of the world’s deadliest spider, the funnel web, may hold promise for heart attack treatment and transplants.
The researchers, led by Meredith Redd of the University of Queensland (UQ), and Sarah Scheuer of Victor Chang Cardiac Research Institute, tested a protein called Hi1a, found in the Fraser Island (K’gari) funnel web venom, on a beating heart that had been exposed to heart attack stresses.
“After a heart attack, blood flow to the heart is reduced, resulting in a lack of oxygen to heart muscle,” says Nathan Palpant of UQ, corresponding author of the paper.
“The lack of oxygen causes the cell environment to become acidic, which combine to send a message for heart cells to die.
“The Hi1a protein from spider venom blocks acid-sensing ion channels in the heart, so the death message is blocked, cell death is reduced, and we see improved heart cell survival.”
Lack of oxygen to tissue is called ischemia, but hearts that have been injured in this way can’t be used for transplants.
“The survival of heart cells is vital in heart transplants – treating hearts with Hi1a and reducing cell death will increase how far the heart can be transported and improve the likelihood of a successful transplant,” says Peter MacDonald, senior cardiologist at St Vincent’s Hospital in Sydney and professor at the Victor Chang Cardiac Research Institute.
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“Usually, if the donor heart has stopped beating for more than 30 minutes before retrieval, the heart can’t be used. 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.”
The work built on previous research that showed the protein showed marked improvement in stroke patients.
“We discovered this small protein, Hi1a, amazingly reduces damage to the brain even when it is given up to eight hours after stroke onset,” says co-author Glenn King, of UQ.
“It made sense to also test Hi1a on heart cells because, like the brain, the heart is one of the most sensitive organs in the body to the loss of blood flow and lack of oxygen.
“For heart attack victims, our vision for the future is that Hi1a could be administered by first responders in the ambulance, which would really change the health outcomes of heart disease.
“This is particularly important in rural and remote parts of Australia where patients and treating hospitals can be long distances apart – and when every second counts.”
While the protein has been tested on human tissue, it has not been tested on living humans. The team are aiming for human clinical trials for stroke and heart disease within three years.
The study was published in Circulation.