Altered serum level of metabolic and endothelial factors in patients with systemic sclerosis

Systemic sclerosis (SSc) is a chronic connective tissue disease characterized by progressive fibrosis, vascular impairment and immune abnormalities. In recent years, adipokines (mediators synthetized by adipose tissue) have been indicated as a possible missing link in the pathogenesis of SSc. The aim of this study was to investigate the serum concentration of metabolic adipose tissue factors: adiponectin, resistin, leptin and endothelial proteins: endothelin-1, fractalkine and galectin-3 in patients with systemic sclerosis. The study included 100 patients with confirmed SSc diagnosis and 20 healthy individuals. The concentration of respective proteins was determined by enzyme-linked immunosorbent assay. The following markers showed statistically significant increased mean concentrations in patients with SSc in comparison to healthy control: resistin (13.41 vs 8.54 ng/mL; P = 0.0012), endothelin-1 (1.99 vs 1.31 pg/mL; P = 0.0072) and fractalkine (2.93 vs 1.68 ng/mL; P = 0.0007). Elevated serum levels of galectin-3 (4.54 vs 3.26 ng/mL; P = 0.0672) and leptin (19,542 vs 14,210 pg/mL; P = 0.1817) were observed. Decreased concentration of adiponectin was found in patients with SSc (5150 vs 8847 pg/mL; P = 0.0001). Fractalkine and galectin-3 levels were significantly higher in diffuse cutaneous SSc than limited cutaneous SSc subset (3.93 ng/mL vs 2.58 ng/mL, P = 0.0018; 6.86 ng/mL vs 3.78 ng/mL, P = 0.0008, respectively) and correlated positively with modified Rodnan Skin Score in total SSc patients (r = 0.376, P = 0.0009; r = 0.236, P = 0.018, respectively). In conclusion, an increased serum level of resistin associated with increased endothelin-1 and fractalkine level and decreased adiponectin level may indicate a significant role of the adipose tissue in the development and progression of vascular abnormalities in patients with systemic sclerosis. Fractalkine and galectin-3 may participate in promoting and exacerbating the fibrotic process in SSc.