Purpose: Multiple cellular functions are stimulated by a Insulin-like Growth Factor-I (IGF-I). The biological activity of IGF-I is modulated by IGFbinding proteins (IGF-BPs) and at the same time, the availability of IGF-BPs may be regulated by the proteolytic activity of some metalloproteinases (MMPs). The aim of the present study was to compare the amounts of IGF-I and IGF-BPs in relation to the activity of MMP-9 in serum and knee synovial fluid from patients with Lyme arthritis (LA) and post-traumatic damage (PTD). Material and methods: Serum and synovial fluids were taken from knee joints of patients with PTD and LA. ELISA (for IGF-I assay), polyacrylamine gel electrophoresis following Western immuneblotting (for IGF-I and IGF-BPs expression), and zymography (for metalloproteinases detection), were used. Results: The concentration of IGF-I in serum and synovial fluid from LA patients were significantly lowered in comparison to PTD patients. Interesting, the synovial fluid /serum ratio of IGF-I concentrations was also lower in LA patients. Low expression IGF-BP3 and high activity of MMP-9 were detected in the LA synovial fluid. Conclusions: The high proteolytic activity of MMP- 9 results in a cleavage of both IGF-I and IGF-BP3 causing a decrease in content of these substances in LA synovial fluid. In addition, the reduction in IGF and IGF-BP amounts may affect the repair processes in joint tissues of LA patients. The low concentration of IGF-I and IGF-BP3 slows down the repair processes in the joint tissues of LA patients.
JavaScript is turned off in your web browser. Turn it on to take full advantage of this site, then refresh the page.