Role of vascular disorders in lung injury in patients with rheumatoid arthritis

Introduction. The incidence of respiratory system involvement in patients with rheumatoid arthritis (RA) has currently increased; thereby new diagnostic methods have been developed actively. Meanwhile role of vascular disorders in pathogenesis of lung injury is almost unknown and single-photon emission computed tomography (SPECT) isn't used as method of lung assessment in RA. The detector of endothelial glycocalyx damage syndecan-1 is little known but potentially perspective serum marker of lung injury in RA. Objective. The purpose of the study was to investigate the role of vascular disorders in lung injury in patients with RA. Materials and methods. 61 patients with RA without comorbid lung diseases were enrolled in the study. Control group consisted of 26 healthy persons. Patients underwent survey and physical examination, high-resolution computed tomography (HRCT) and SPECT of the lungs and pulmonary function tests (PFTs). Also serum levels of rheumatoid factor (RF), anti-cyclic citrullinated peptide antibodies (ACCP) and syndecan-1 were measured. Results. All patients developed microcirculation impairment on SPECT. Vascular disorders were according to changes of lung structure detected by HRCT (r = 0.434; p = 0.044). Areas of hypoperfusion matched with ground glass opacities, lung fibrosis, branching linear structures and airway obstruction on HRCT-SPECT fusion scans. Syndecan-1 level was higher in patients with RA compared with healthy controls (р = 0.019). Conclusion. Vascular disorders are important in pathogenesis of lung injury in RA, and SPECT has high sensitivity in lung assessment. Perfusion impairment in lungs correlates with syndecan-1 level, thus syndecan-1 could be used as marker of lung injury in RA thereafter.