High-level of circulating progranulin and its relationship with plasma glycosaminoglycans, as biochemical indicators of proteolytic and oxidative aggrecan modification, in the course of juvenile idiopathic arthritis

Abstract

Aim: Progranulin (PGRN) plays an important role in cartilage metabolism. The disturbed interaction between PGRN and glycosaminoglycans (GAGs), as biochemical indicators of aggrecan modification, may contribute to articular damage observed in the course of juvenile idiopathic arthritis (JIA). Hence, the aim of this study was to assess quantitatively the level of progranulin in children with JIA as well as to evaluate the correlation between PGRN and GAGs, MMP-3 (matrix metalloproteinase 3), ADAMTS-4 (a disintegrin and metalloproteinase with thrombospondin motifs 4) as well as the total oxidative status (TOS) and the total antioxidative status (TAS). We have also evaluated interactions between PGRN and inflammatory and anemia indicators, i.e. C-reactive protein (CRP), and hemoglobin (Hb), respectively. Material/Methods: The PRGN level was measured using the immunoenzymatic method, in blind tested coded plasma samples, obtained from both JIA patients before and after treatment and from healthy children. Results: Increased (p<0.001) plasma progranulin in JIA patients before treatment was observed. Therapy resulted in a decrease in the PRGN level. However, the plasma PRGN level still remained higher (p<0.05) than in the controls. In both groups of patients, we have revealed an insignificant correlation between plasma PGRN and GAGs levels. Moreover, a significant correlation between plasma PGRN level and MMP-3, ADAMTS-4, TOS, TAS, CRP and Hb levels, was stated in untreated JIA patients. Conclusions: The obtained results may indicate that PGRN has antioxidative properties in the course of JIA, but do not confirm the protective roles of this glycoprotein in respect to the destructive effects of proteolytic factors.