487-P: In Vivo Vasculogenic Tissue Reprogramming and Rescue of Diabetic Ischemic Tissue

Our recent work reported on the identification of the vasculogenic fibroblast (VF) that is capable of generating new blood vessels during tissue repair (Pal et al. Nat Com, 2023). While VF are physiologic and injury-inducible, inducible VF generation is blunted under conditions of diabetes. We report that such barrier may be overcome by the induction of fibroblast Etv2, Fli1 and Foxc2 (EFF) using tissue nanotransfection (TNT) technology (PMIDs: 28785092, 34837085, 35819852). To understand the mechanisms underlying VF function and significance, we developed EFF^fl/fl COL1A2^creER mice. In these mice, EFF regions in fibroblasts (COL1A2⁺ cells) are induced in response to tamoxifen. To gain insight into the significance of VF in vivo, hind limb ischemia (HLI) studies were performed. Significant overexpression of EFF was noted in laser capture dissected dermal fibroblast tissue elements of tamoxifen treated HLI mice (n=6, P < 0.05). Tamoxifen treatment enhanced hindlimb perfusion, as determined by laser speckle perfusion imaging (Perimed Inc.), in HLI mice (n=7, P < 0.05). This rescue was associated with increased abundance of COL1A2⁺VWF⁺ VF as compared to control (EFF^fl/fl) (n=7, P<0.05). These favorable rescue findings were reproduced in diabetic (db/db) mice subjected to HLI (n=7, P<0.05).

In conclusion, vasculogenic reprogramming in vivo is capable rescuing ischemic tissue under both nondiabetic and diabetic conditions.