“…Regenerative cell therapies in the fast-emerging field of tissue engineering are based on the anticipation that delivered cells rebuild the affected tissues [ 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 ]. Various technologies tested to introduce adequate stem cells for the construction of functioning tissues and organs, both in vitro and in vivo, have had only minimal success [ 8 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 ]. In most cases, in vitro-constructed non-vascularized 3D tissue-engineered complex tissues based on differentiated stem cells seemed to fade upon their implantation.…”