PECAM1 and systemic sclerosis: As shown in Figure 12 and Table 2, the endothelial markers’ expression, namely CD31 and VE-cadherin, and the mesenchymal markers’ expression, namely vimentin and N-cadherin, were lower and higher, respectively, in HUVECs treated with the EVs isolated from SSc patients than those found in HUVECs treated with EVs isolated from HCs.