Hydrogel delivery of ASCs to promote ischemic tissue flap survival. (A) WT and DM (1 and 2) ASC-seeded hydrogels and unseeded controls were inset following creation of a full-thickness peninsular skin flap, (B) resulting in the creation of a reproducible ischemic gradient. (C) Tissue survival and vascularization as determined by (D) CD31 immunohistochemistry staining and (E) quantification were assessed at day 10. Scale bar = 50 μm. *P ≤0.05.