Relationship between Insulin-like Growth Factor and Patients with Systemic Sclerosis

  Objective  To analyze the role of insulin-like growth factor (IGF) in patients with systemic sclerosis (SSc) and explore the relationship between these cytokines and the clinical characteristics of SSc.

  Methods  Serum samples were obtained from 24 SSc patients12 patients with diffuse cutaneous SSc (dcSSc) and 12 patients with limited cutaneous SSc (lcSSc), 12 healthy controls and 6 patients with systemic lupus erythematosus (SLE). The levels of circulating IGF-Ⅰ, IGF-Ⅱ, insulin-like growth factor binding protein (IGFBP)-3, IGFBP-5, IGFBP-related protein 1 (IGFBP-rP1), and transforming growth factor-β1 (TGF-β1) were measured with ELISA kits.

  Results  The mean serum IGF-Ⅰ and IGFBP-3 levels were significantly higher in SSc patients than in healthy controls(49.21±37.94) ng/ml vs. (15.54±9.07) ng/ml; (3.38±2.09) ng/ml vs. (1.00±0.83) ng/ml, both P < 0.001. A positive correlation between serum IGF-Ⅰ and IGFBP-3 levels was found (r=0.883, P < 0.001). Serum IGF-Ⅰ and IGFBP-3 levels were not associated with age, disease course, and the modified Rodnan total skin thickness score. There were no significant differences in serum IGF-Ⅰ and IGFBP-3 levels between patients with Scl-70 antibody and patients without Scl-70 antibody. Also, the serum IGF-Ⅰ and IGFBP-3 levels showed no significant difference between patients with pulmonary interstitial fibrosis and patients without pulmonary interstitial fibrosis. There were no significant differences in serum IGF-Ⅱ, IGFBP-5, and IGFBP-rP1 levels between patients with SSc and healthy controls.

  Conclusion  Serum IGF-Ⅰ and IGFBP-3 levels increase in SSc patients. IGF may play a role in pathogenesis of SSc.