ASC, BMSC, and DF from IV to XI passage at 90% of confluence were incubated in starving conditions for 72 hours (the absence of FBS). No signals of cell suffering were ever observed. The medium was collected and centrifuged at 2500g for 15 minutes at 4°C to remove dead cells, large apoptotic bodies, and debris. The supernatants were split in half to obtain paired CM and EV samples, while donor cells were counted in order to correlate cell number to the final products (CM or EV). An aliquot of the CM was concentrated about 40-50 times by centrifuging at 4000g for 90 minutes at 4°C in AmiconUltra-15 Centrifugal Filter Devices with 3 kDa molecular weight cutoff (Merck Millipore, Burlington, MA, USA). This procedure allows the retention of the vesicular component of cell secretome, as previously demonstrated in the studies of Carlomagno et al., Niada et al., and Giannasi et al.13 ,14 (link),18 In parallel, EV were isolated starting from CM through differential centrifugation at 100 000g (L7-65; Rotor 55.2 Ti; Beckman Coulter, Brea, CA, USA), 4°C for 70 minutes).14 (link),21 (link) The resulting CM and EV were kept at −80°C until use.