A New Target for Septic Arthritis

A matrix metalloproteinase enzyme found in all vertebrates, invertebrates, and plants plays a prominent role in the joint destruction that occurs in septic arthritis, a group of Italian researchers reported.

After infection with group B streptococci, joints of 80% of wild-type mice with intact matrix metalloproteinase-2 (MMP-2) had become markedly arthritic. These joints, including the subcutaneous and periarticular tissues as well as the joint cavity itself, showed inflammatory infiltrates and a pronounced influx of inflammatory cytokines, such as interleukin-6 and tumor necrosis factor-alpha.

In comparison, mice lacking the MMP-2 enzyme had erythema and edema, but only in the subcutaneous tissue. The majority of the joints had no histologic evidence of arthritis.

The researchers, led by Luciana Tissi, PhD, of the University of Perugia, explained that these findings are important because invasive infections in adults caused by group B streptococci - once largely limited to neonates, infants, and pregnant women - are on the rise in nonpregnant adults. The identification of MMP-2 as an important contributor suggests that this enzyme could serve as a possible therapeutic target for treating septic arthritis, they wrote in the April issue of Arthritis & Rheumatism.

- N.W.

By MedPage Today Staff