An Antidote for Arthritis : Scorpion Venom?!
Rheumatoid arthritis (RA) is an autoimmune disease in which the body’s immune system – which normally protects its health by attacking foreign substances like bacteria and viruses – mistakenly attacks the joints. This creates inflammation that causes the tissue that lines the inside of joints (the synovium) to thicken, resulting in swelling and pain in and around the joints.
If the inflammation goes unchecked, it can damage cartilage, the elastic tissue that covers the ends of bones in a joint, as well as the bones themselves. Over time, there is loss of cartilage, and the joint spacing between bones can become smaller. Joints can become loose, unstable, painful and lose their mobility. Joint deformity also can occur, which is irreversible.
But these patients might eventually be cleared of the disease, thanks to a new study led by Dr. Christine Beeton at Baylor College of Medicine that has now determined that one component out of hundreds in scorpion venom can ease the symptoms of RA in animal models; there also weren’t side effects like those seen with other treatments like this one.
“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 target the immune cells involved in the disease and none are specific for FLS. Beeton and her colleagues studied FLS looking for an ‘Achilles’ heel’ that would allow them to prevent or stop them from damaging the joints.
“In previous work, we identified a potassium channel on FLS of patients with rheumatoid arthritis and found that the channel was very important for the development of the disease,” Beeton said. “We wanted to find a way to block the channel to stop the cells damaging the joints.”
“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,” said first author Dr. Mark Tanner, a graduate student in the Beeton lab during the development of this project.
In this study, they investigated whether this venom component, called iberiotoxin, would be able to specifically block the FLS potassium channel and reduce the severity of rheumatoid arthritis in rat models of the disease. They found that iberiotoxin stopped the progression of the disease. In some cases it reversed the signs of established disease, meaning that the animals had better joint mobility and less inflammation in their joints with no side effects.
Dr. Christine Beeton said, “Although these results are promising, much more research needs to be conducted before we can use scorpion venom components to treat rheumatoid arthritis.”
“We think that this venom component, iberiotoxin, can become the basis for developing a new treatment for rheumatoid arthritis in the future.”
