Vascular Remodelling and Mesenchymal Transition in Systemic Sclerosis

Figure 1

Vascular remodelling and capillaroscopic pattern in Systemic Sclerosis (SSc). (a) Stenoocclusive remodelling in SSc microvasculature (bottom right) is believed to result from an abnormal reparative attempt triggered by chronic endothelial damage, which drives intima-media hyperplasia and increased ECM production within the vessel wall. Mesenchymal cells, specifically myofibroblasts with a highly secretory phenotype, are the main final effectors responsible for these structural changes. Myofibroblasts in SSc vessels can originate from multiple cellular sources (upper left), either of mesenchymal origin, such as pericytes or fibroblast, or of nonmesenchymal origin, such as endothelial cells. (b)–(d) Capillaroscopic pattern in normal subjects (b) and scleroderma patients at magnification 200x ((c): “active” SSc pattern; (d): “late” SSc pattern). Note the heterogeneity in the architecture and morphology of SSc capillaries with frequent ectasias (black arrowheads). In the “active” scleroderma pattern there are plenty of giant capillaries (i.e., more than 50 μm of diameter) and microhaemorrhages (white arrowheads), with mild loss of capillaries. In the “late” scleroderma pattern giant capillaries and microhaemorrhages are less frequent, but a severe loss of capillaries is evident, with extensive avascular areas (white arrows).