A potentially life-saving treatment for heart attack victims has beendiscovered from a very unlikely source – the venom of one of the world’sdeadliest spiders.
A drug candidate developed from a molecule found in the venom of the FraserIsland (K’gari) funnel web spider can prevent damage caused by a heart attackand extend the life of donor hearts used for organ transplants.
The discovery was made by a team led by Dr Nathan Palpant and Professor GlennKing from The University of Queensland (UQ) and Professor Peter Macdonald fromthe Victor Chang Cardiac Research Institute.
Dr Palpant, from UQ’s Institute for Molecular Bioscience (IMB), said the drugcandidate worked by stopping a ‘death signal’ sent from the heart in the wakeof an attack.
“After a heart attack, blood flow to the heart is reduced, resulting in a lackof oxygen to heart muscle,” Dr Palpant said.
“The lack of oxygen causes the cell environment to become acidic, whichcombine to send a message for heart cells to die.
“Despite decades of research, no one has been able to develop a drug thatstops this death signal in heart cells, which is one of the reasons why heartdisease continues to be the leading cause of death in the world.”
Dr Palpant tested the drug candidate, a protein called Hi1a, using beatinghuman heart cells exposed to heart attack stresses to see if the drug improvedtheir survival.
“The Hi1a protein from spider venom blocks acid-sensing ion channels in theheart, so the death message is blocked, cell death is reduced, and we seeimproved heart cell survival,” he said.
There are currently no drugs in clinical use that prevent the damage caused byheart attacks.
Victor Chang Cardiac Research Institute and St Vincent’s Hospital seniorcardiologist Professor Macdonald said this incredible result had been decadesin the making.
“This will not only help the hundreds of thousands of people who have a heartattack every year around the world, it could also increase the number andquality of donor hearts, which will give hope to those waiting on thetransplant list,” Professor Macdonald said.
“The survival of heart cells is vital in heart transplants — treating heartswith Hi1a and reducing cell death will increase how far the heart can betransported and **** improve the likelihood of a successful transplant.
“Usually, if the donor heart has stopped beating for more than 30 minutesbefore retrieval, the heart can’t be used – even if we can buy an extra 10minutes, that could make the difference between someone having a heart andsomeone missing out. For people who are literally on death’s door, this couldbe life-changing.”
The discovery builds on earlier work by Professor King, who identified a smallprotein in the venom of the Fraser Island (K’gari) funnel-web spider that wasshown to markedly improve recovery from stroke.
“We discovered this small protein, Hi1a, amazingly reduces damage to the braineven when it is given up to eight hours after stroke onset,” Professor Kingsaid.
“It made sense to also test Hi1a on heart cells, because like the brain, theheart is one of the most sensitive organs in the body to the loss of bloodflow and lack of oxygen.
“For heart attack victims, our vision for the future is that Hi1a could beadministered by first responders in the ambulance, which would really changethe health outcomes of heart disease.
“This is particularly important in rural and remote parts of Australia wherepatients and treating hospitals can be long distances apart – and when everysecond counts.
“Also, this could help for the transfer of donor hearts for cardiactransplantation – allowing these donor hearts to be transported over longerdistances and therefore increasing the network of available donors andrecipients.”
The protein has been tested in human heart cells, and the team is aiming forhuman clinical trials for both stroke and heart disease within two to threeyears.
This research was published in Circulation and funded by The University ofQueensland, the Australian National Health and Medical Research Council andthe National Heart Foundation of Australia. The lead authors are Dr MeredithRedd (Institute for Molecular Bioscience, UQ) and Dr Sarah Scheuer (VictorChang Cardiac Research Institute).
Image above left: Dr Nathan Palpant. Image above right: Dr Meredith Redd.
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