Assessment of the serum levels of SCUBE (signal peptide-cub-EGF domain-containing protein) -1,2 and 3 in patients with systemic sclerosis and its association clinical parameters and ultrasound skin thickness

Systemic sclerosis is a chronic, multisystemic, autoimmune disease with unknown etiology. It is accepted that the pathogenesis is due to vasculopathy, immunological activation and fibrosis triad. However, the pathogenesis has not been fully elucidated. Signal peptide-CUB-EGF domain-containing protein (SCUBE) is a family of newly defined proteins known as secretagogues or membrane proteins. These proteins have been shown to be associated with angiogenesis and inflammation. In this study, we aimed to investigate serum levels of SCUBE-1, SCUBE-2 and SCUBE-3 in systemic sclerosis; and association with clinical findings and ultrasonographic skin thickness. Thirty patients who met the ACR / EULAR 2013 criteria for scleroderma and 44 healthy volunteer who matched the patient group in terms of age and gender were included in the study. Valentini disease activity index, modified Rodnan skin score, Duruöz hand index, HAQ stanford health assessment questionnaire and SF-36 forms were used in the evaluation of patients. Simultaneous ultrasonographic skin thickness measurements were performed. Serum SCUBE levels were measured by enzyme-linked immunosorbent assay (ELISA). There was no statistically significant difference between the serum SCUBE levels of the patients with systemic sclerosis and the control group (p: 0.126 for SCUBE-1, p: 0.176 for SCUEB-2, p: 0.195 for SCUBE-3). In correlation analysis; negative correlation was determined between serum SCUBE-1 level and FEV-1 (p: 0.036); positive correlation was found between serum SCUBE-2 level and Duruöz hand index (p: 0.029), negative correlation with the FVC value (p: 0.032), the DLCO value (p: 0.054), hemoglobin level (p: 0.01) and serum C4 levels (p: 0.04); and finally negative correlation between serum SCUBE-3 and echocardiographic pulmonary artery pressure (p: 0.014) and CK level (p: 0.04) was found. There was no correlation between serum SCUBE levels and ultrasonographic skin thicknesses. However, there was a positive correlation between the ultrasonographic skin thickness and the modified Rodnan skin score (p: 0.001). In conclusion, we investigated the role of serum SCUBE levels in the pathogenesis of systemic sclerosis and we found no statistically significant difference between patient and control group. Serum SCUBE levels correlated with some clinical and laboratory parameters. Further clinical trials are needed to better understand the contribution of these molecules to the pathogenesis and progression of systemic sclerosis.