Researchers reverse arthritis damage in mice

Researchers have developed a treatment in mice that reverses the damage caused by rheumatoid arthritis. The findings could point the way towards new treatments for the thousands of people crippled by this progressive disease.

The research by Dr Mario Delgado and colleagues of the Complutense University in Spain is published this morning in Nature Medicine. It describes how a natural biochemical, vasointestinal peptide (VIP), delayed the onset of the disease in mice, reduced the destruction of cartilage and bone and brought about improvements where disease was already established.

Rheumatoid arthritis causes serious inflammation in joints, making movement painful and in severe cases impossible. It affects about 500,000 men and women in the Republic, but the disease knows no age restrictions. About 5,000 children under 12 here suffer from it.

Most treatments are aimed at pain control since no cure is available. Some of the latest treatments seek to interfere with the body's natural inflammatory process as a way to reduce symptoms, but these do not reverse the symptoms.

VIP is a "neuropeptide" present in the body's lymphatic system. It has a number of biological functions, Dr Delgado writes, and is known to have a powerful anti-inflammatory action. "VIP has emerged as one of the more promising candidates for treatment of [rheumatoid arthritis]," he said.

"Mice treated with VIP showed delayed onset, lower incidence and decreased severity of [disease] in comparison with untreated arthritic mice, as assessed by clinical score and paw swelling," he said.

"We saw no remission in therapeutic effects two weeks after cessation of VIP administration, indicating that no additional neuropeptide is necessary after a short period of VIP treatment to maintain protection from the disease. Importantly, VIP can prevent and ameliorate already established disease."

Dr Delgado believes VIP represents a "viable candidate" for the development of treatments for rheumatoid arthritis. It will take some years, however, before a treatment for humans could be developed if this approach was found to work in humans.

Scientists believe VIP blocks the production of the cascade of substances released in the body during the onset of inflammation. Immune system messaging chemicals called cytokines can provoke inflammation in an arthritic joint but their action is dampened down.