Increased decorin and type V collagen in SSc pulmonary fibrosis

Abstract

Objective: To evaluate COL V and decorin expression in pulmonary tissue and to characterize biochemical profile of COLV from lung fibroblasts culture from SSc patients. Method: We evaluated COL V and decorin expression and tridimensional reconstruction (3D) of 6 patients with SSc without pulmonary hypertension that underwent surgical lung biopsy and as control was obtained lung fragments from 6 normal individuals who died from trauma. COL V amount in lung sections was evaluated with immunofluorescence. To biochemical characterization of COL V from lung fibroblasts culture was used quantitative immunoblot. Results: It was found that the structure of COLV fibers was distorted and strongly thickened in lung tissue from SSc patients compared with thin fibers pattern in the healthy controls. Decorin was distributed around COL V fibrils in the bronchovascular interstitium and vascular walls. Histomorphometric analysis of SSc lung demonstrated increased expression of both COL V and decorin when compared to the control (p<0.01). The semiquantitative imunoblot detected an increased high molecular weight COLV fraction in patients when compared to the control. Conclusion: The over expression and unusual organization of COLV fibers with biochemical changes associated to increased decorin indicates that matrix signalization pathway is involved in COLV fibrillogenesis process in SSc pulmonary fibrosis.