The intramuscular injection of TNF-α-CM in the simulated chemotactic migration and in vivo homing of human endothelial progenitor cells (EPCs) promoted angiogenesis in the ischemia limb through IL-6 and IL-8 dependent mechanisms, which improved blood perfusion and inhibited tissue necrosis in the ischemia hindlimbs [77]. Here, TNF is linked to ischemia.