Expression Of Insulin-like Growth Factor System In Patients With Systemic Sclerosis

Objectives:To analyze the role of insulin-like growth factor (IGF) system in patients with systemic sclerosis (SSc) and the relationship between these cytokines and clinical characteristics of SSc.Materials and Methods:Serum samples were obtained from24patients with SSc, concluding12patients with dcSSc and12patients with lcSSc. All patients fulfilled the criteria proposed by the American College of Rheumatology. Control serum samples were also collected from healthy age-and sex-matched volunteers and patients with systemic lupus erythematosus (SLE). Levels of circulating IGF-Ⅰ,IGF-Ⅱ, IGFBP-3, IGFBP-5, IGFBP-rP1and TGF-β1were measured with ELISA kits. Statistical analysis of the clinical manifestations as well as serum antibodies spectrum was carried out with SPSS17.0to analyze the relationship between IGF system and clinical characteristics of SSc. Statistical significance was set P<0.05.Results:1. Mean serum IGF-I levels were significantly higher in SSc patients than healthy controls[(49.21±37.94) ng/ml vs.(15.54±9.07) ng/ml, P<0.001]. Serum IGF-I levels were not associated with age, course of disease and the modified Rodnan total skin thickness score. There were no significant differences in serum IGF-I levels between patients with Scl-70antibody and patients without Scl-70antibody. There were no significant differences in serum IGF-1levels between patients with pulmonary interstitial fibrosis and patients without pulmonary interstitial fibrosis. 2. Mean serum IGFBP-3levels were significantly higher in SSc patients than healthy controls [(3.38±2.09) ng/ml vs.(1.00±0.83) ng/ml, P<0.001]. Serum IGFBP-3levels were not associated with age, course of disease and the modified Rodnan total skin thickness score. There were no significant differences in serum IGFBP-3levels between patients with Scl-70antibody and patients without Scl-70antibody. There were no significant differences in serum IGFBP-3levels between patients with pulmonary interstitial fibrosis and patients without pulmonary interstitial fibrosis.3. A positive correlation between serum IGF-I and IGFBP-3levels (r=0.883, P<0.001was detected.4. There were no significant differences in serum IGF-Ⅱ,1GFBP-5and IGFBP-rP1levels between patients with SSc and healthy controls.Conclusion:Mean serum IGF-I and IGFBP-3levels were significantly higher in SSc patients than healthy controls; IGF system may play a role in pathogenesis of SSc.