Strong currents and sharks aren't the only threat to saltwater swimmers in Australia. A deadly jellyfish often tops their list of threats.
But researchers working with mice have discovered a potential antidote to the lethal sting of the Australian box jellyfish – the world's most venomous sea creature.
The treatment in question? A cholesterol drug.
Effective on live mice
Each box jellyfish carries enough venom to kill more than 60 people. A sting causes skin tissue death (necrosis) and severe pain. If the dose of venom is large enough, cardiac arrest and death can occur within minutes.
"Our drug works on the big beast... We know the drug will stop the necrosis, skin scarring and the pain completely when applied to the skin," said study senior author Greg Neely.
He and his colleagues at the University of Sydney had been using CRISPR genome editing techniques – a form of genetic editing where sections of DNA are taken out, modified or replaced – to investigate how the jellyfish venom works. From that, they discovered that the venom pathway required cholesterol, so an existing cholesterol medicine would block the effects of the venom if injected within 15 minutes.
Neely and team found that the medicine was effective on human cells in the laboratory and on live mice. They'll now try to develop an antidote that can be applied to the skin.
"We were looking at how the venom works, to try to better understand how it causes pain. Using new CRISPR genome editing techniques we could quickly identify how this venom kills human cells," Neely said in a university news release.
About 60 tentacles
"Luckily, there was already a drug that could act on the pathway the venom uses to kill cells. And when we tried this drug as a venom antidote on mice, we found it could block the tissue scarring and pain related to jellyfish stings," said Neely, an associate professor and pain researcher.
"It is super-exciting," he added. However, it's important to note that results of animal experiments aren't always replicated in humans.
Study lead author Raymond Lau explained the molecular antidote.
"Since there are lots of drugs available that target cholesterol, we could try to block this pathway to see how this impacted venom activity," Lau said. "We took one of those drugs, which we know is safe for human use, and we used it against the venom, and it worked."
Neely said it's not yet known if the drug will stop a heart attack associated with the jellyfish sting. "That will need more research and we are applying for funding to continue this work," he noted.
This particular jellyfish has about 60 tentacles that can stretch almost 10 feet, the researchers noted. It's found in northern Australian waters and around the Philippines.
The study was published in the journal Nature Communications.
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