Since VEGF, bFGF, IGF-1, TGF-β1, and TGF-β2 were significantly elevated after PHD2 silencing, and previous studies had suggested that these cytokines played an active role in NEC repair20,22,23, we further studied if the beneficial effect of PHDMSC-CM on NEC was associated with these cytokines. Here, IGF1 is linked to necrotizing enterocolitis.