The UQ study found the neurotoxic venom of fat-tailed scorpions also causes blood clots.
(Photo credit: Adobestock/ Ernie Cooper )
A University of Queensland study has shown a deadly scorpion's venom carries an extra biochemical sting that could be used to guide future medical treatments and tests.
Professor Bryan Fry and PhD candidate Sam Campbell from UQ's School of the Environment investigated the blood clotting effect of fat-tailed scorpion venoms.
"Found in the Middle East and North Africa, scorpions in the genus Androctonus have a potentially lethal neurotoxic venom that can overwhelm the nervous system leading to heart failure," Mr Campbell said.
"We've now shown how their venom also causes rapid clots in human blood.
"Clinical reports had hinted that some scorpion sting patients had abnormal clotting, but until now the mechanism behind it wasn't known.
"By introducing the venoms to human plasma, we saw them accelerate clotting and then mapped the molecular steps responsible.
"It was exciting be able to explain the biochemistry of this procoagulant effect because it opens a new chapter in how we study venom evolution and medical effects."
The research revealed Androctonus venoms activate major clotting factors in blood, particularly Factors VII and X, and this process depends on Factor V being in its activated form.
The team also tested neutralisation and showed an antivenom routinely used to treat fat-tailed scorpion stings did not prevent the procoagulant activity.
Mr Campbell hopes the work improves the treatment of scorpion envenomation by alerting medical staff to watch and test for clotting.
"While the available antivenom is effective against the neurotoxic effects of the scorpion venom, in our testing it did not affect the clotting.
"We found that 2 small-molecule metalloprotease inhibitors, marimastat and prinomastat, neutralised the procoagulant effects in our testing," he said.
"Seeing the inhibitor drugs block the clotting activity also told us a lot about the enzyme class involved.
"And it highlights that adjunct treatments targeting venom enzymes could be valuable, especially when antivenom does not fully neutralise a specific effect."
Professor Fry said the findings have the potential to be translated into diagnostic tools for blood disorders or treatments.
"Venoms contain highly evolved molecules that act with precision on human physiology," Professor Fry said.
"When you uncover a new mechanism, you reveal molecular tools that can seed drug discovery, even if the final medicines look nothing like the original venom components.
"This work shows that some scorpions can biochemically hijack core components of the clotting cascade in a way we typically associate with some snake venoms.
"Being novel, they may hold the key to saving lives through controlling blood loss during surgery or after injury."
The research is published in Biochimie.
