IGF-1, cytokines and biochemical bone turnover markers in synovial fluid and serum of patients with primary and secondary osteoarthritis of the hip

Abstract

Background: To compare the concentrations of IGF-1, bone turnover markers (BSAP, CTx) and cytokines in patients with advanced hip osteoarthritis and to evaluate associations between these parameters and disease etiopathogenesis. Materials and methods: Samples of joint fluid and serum were collected from 17 patients with primary hip osteoarthritis (POA) and 6 patients with avascular osteonecrosis of the hip (SOA) who underwent hip surgery. Concentration of IGH, IL-6, IL-8, IL-10, CTx and BSAP activity were measured by ELISA. Results: Patients with osteoarthritis had serum IGF-1 in the lower range of reference values but those with osteonecrosis - below this range. Serum CTx concentration was, however, significantly higher in SOA than in POA cases (0.58±0.19 and 0.39±0.15, respectively, P=0.02). Synovial fluid IGF-1 in SOA patients was lower (P=0.008) and CTx higher than in POA cases (P<0.001). In patients with primary osteoarthritis synovial fluid IGH, CTx, IL-6 and IL-8 concentrations correlated with those in the serum. Similar and strong associations, but only for CTx and IL-8, were found in cases with osteonecrosis. IGF-1 in synovial fluid correlated with BSAP activity in POA patients. Positive correlation was observed between CTx and IL-8 in synovial fluid and serum. In patients with osteonecrosis, serum IGF-1 was directly related to IL-10 while negative association was found between CTx and IL-10. Conclusions: IGF-1 level may constitute a risk factor predisposing to osteoarthritis and may be related to disease etiopathogenesis. Very low IGF-1 concentration in serum (PPV>70%) or synovial fluid may Indicate necrotic origin of degenerative joint disease. The data reported here show that avascular osteonecrosis is characterized by a more catabolic state, reflected by low IGF-1 with concomitant increase in bone resorption and pro-inflammatory indices.