Jab of tiny pellets could stop pain of arthritis
PAINzAppINg pellets are being fired into the knees to take the discomfort out of arthritic joints. The tiny spheres — made from gellike plastic, each 30 or more times thinner than a credit card — increase in size once injected into the knee.
They work by blocking rogue blood vessels containing new nerve fibres that develop with the onset of osteoarthritis and contribute to the pain.
A pilot study involving five patients who failed to respond to other nonsurgical treatments showed that injecting an arthritic joint with thousands of these microspheres can cut symptoms by a third or more, with longlasting effects.
Four of the five had a significant improvement in pain, which was still apparent three months later, and, overall, symptoms more than halved, according to the study carried out by the Vascular Institute of Virginia in the U.S. and reported in the current issue of the Journal of Vascular and Interventional radiology.
The pellets are already used to treat fibroids, noncancerous growths that develop in, or, around the womb. once the fibroids lose their blood supply, they disappear.
ReSeArCherS now believe that the same approach could work for osteoarthritis, the most common form of arthritis, affecting millions of people in Britain.
The condition develops as the joint surface of cartilage wears away — usually with advancing age — causing inflammation and pain. As the underlying bone becomes exposed and rubs against other bone, the pain worsens.
Inflammation is thought to lead to the production of growth factors and other compounds that trigger the growth of new blood vessels — a process known as angiogenesis. These newly formed blood vessels grow into the cartilage and adjacent bone, bringing with them new nerve fibres that cause increased pain.
The microsphere treatment is thought to destroy these new, abnormal blood vessels and nerves by cutting off the supply of nutrients they need to survive. This reduces inflammation and pain, and halts or delays further joint damage.
During the treatment, rogue blood vessels are identified with mrI scans and then injected with the solution containing the microspheres. once released into the body, the spheres expand by up to onethird and become jammed in the blood vessel, blocking off its blood supply. The blood vessel eventually collapses and the dead tissue is absorbed by the body.
The Virginia team is now conducting a larger trial involving 20 patients with osteoarthritis of the knee, who will be monitored for six months after having the treatment.
Currently, treatment for osteoarthritis in the knee begins with lifestyle changes including weight loss and, in severe cases, requires joint replacement surgery.
‘The excess growth of blood vessels in the knee of osteo
arthritis patients is known, and previous trials into treatments that effectively block this process have shown some promising effects,’ says Dr Stephen Simpson, director of research and programmes at Arthritis research UK.
‘however, this is an ongoing trial, meaning that it is premature to predict what the potential results will mean for the 4.7million people in the UK living with knee osteoarthritis.’
meANWhILe, scientists believe they are on the verge of developing the first gene therapy for osteoarthritis that could be injected straight into the joint.
The idea is that, rather than injecting a drug that could be quickly washed away by fluid in the joint, with gene therapy you deliver DNA that then encourages new tissue to grow.
The jab contains a virus that delivers allogenic chondrocytes, cells that help to regenerate tissue, as well as transforming growth factor, a protein that helps with cell growth.
According to a report published in the journal human gene Therapy, the treatment has been shown to work in principle and has been approved for use in Korea. Trials will soon take place in the U.S. to check if it is as effective as other treatments.