Scorpion venom could hold the key to a new treatment for rheumatoid arthritis (RA), US researchers say.
A group of researchers led by Dr Christine Beeton at Baylor College of Medicine found that, in animal models, one of the hundreds of components in scorpion venom can reduce the severity of the disease — without inducing side effects associated with similar treatments.
The findings have been published in the Journal of Pharmacology and Experimental Therapeutics.
“Rheumatoid arthritis is an autoimmune disease — one in which the immune system attacks its own body. In this case, it affects the joints,” said Beeton, associate professor of molecular physiology and biophysics and member of the Dan L Duncan Comprehensive Cancer Center at Baylor College of Medicine. “Cells called fibroblast-like synoviocytes (FLS) play a major role in the disease. As they grow and move from joint to joint, they secrete products that damage the joints and attract immune cells that cause inflammation and pain. As damage progresses, the joints become enlarged and are unable to move.”
Current treatments for RA target the immune cells involved in the disease and none are specific for FLS.
The latest study followed previous work in which the researchers identified a potassium channel on FLS of patients with RA and found that the channel was important for the development of the disease.
“We wanted to find a way to block the channel to stop the cells damaging the joints,” Beeton explained.
“Scorpion venom has hundreds of different components. One of the components in the venom of the scorpion called Buthus tamulus specifically blocks the potassium channel of FLS and not the channels in other cells such as those of the nervous system,” added first author Dr Mark Tanner, a graduate student in Beeton’s lab during the development of this project. “Here, we investigated whether this venom component, called iberiotoxin, would be able to specifically block the FLS potassium channel and reduce the severity of the rheumatoid arthritis in rat models of the disease.”
Results showed that, when the researchers treated rat models of the disease with iberiotoxin, they stopped the progression of the disease. In some cases, they reversed the signs of established disease, meaning that the animals had better joint mobility and less inflammation in their joints.
What’s more, treatment with iberiotoxin did not induce side effects, such as tremors and incontinence, observed when treating with another channel blocker called paxilline.
Further research is needed, but this venom component has the potential to lead to a new treatment for rheumatoid arthritis in the future.