Researchers at the University of Illinois at Chicago College of Medicine have identified two protein molecules that seem to promote the abnormal formation of blood vessels in joints affected by rheumatoid arthritis (RA), finding that the substances are present at higher levels in the joints of patients affected by the disease. Shiva Shahrara, PhD, explains, “Our results show, for the first time, that these two proteins — a receptor and its corresponding binding protein — play a key role in the progression of rheumatoid arthritis pathology.”

Shahrara and colleagues wanted to see if the protein CCL28 and its receptor could be found in patients’ affected joints. The research team measured the levels of the proteins in the tissues and fluid of joints from patients with RA and with osteoarthritis (OA). Patients of both types had protein levels in their joints that were significantly higher than individuals without joint disease. According to the University of Illinois news release, the investigators found that CCL28, which is over-produced in joints affected by rheumatoid arthritis, attracts the surface-lining cells that carry its receptor.

The University of Illinois news release notes that when the researchers added CCL28 to cells carrying the receptor, the cells organized into blood vessels. However, if they chemically blocked the receptor and added CCL28, formation of blood vessels was reduced. Shahrara says the findings provide “strong evidence” that the binding of CCL28 to joint-lining cells carrying its corresponding receptor is a necessary step in angiogenesis.

The results of the study are reported in the journal Annals of the Rheumatic Diseases.

Source: University of Illinois at Chicago