NRP1 and systemic sclerosis: In particular, previous studies from our group demonstrated that circulating levels of the angiogenic regulator soluble neuropilin 1 (sNRP1) progressively decreased in SSc patients, reaching the lowest values in those with the most severe architectural microvascular changes, while serum levels of semaphorin 3E (Sema3E) and Slit2 were increased, especially in patients with early peripheral vascular involvement [18,20,21,22].