Tirzepatide improves angiogenesis after diabetic hindlimb ischemia through Akt/eNOS and ERK1/2 pathways

Critical limb ischemia (CLI) represents a severe vascular complication of type 2 diabetes, primarily driven by impaired angiogenic capacity, and frequently results in limb amputation or mortality. Here, we investigated the therapeutic potential of tirzepatide in promoting perfusion recovery in diabetic hindlimb ischemia and delineated the underlying molecular mechanisms. Human umbilical vein endothelial cells (HUVECs) exposed to high glucose were employed to evaluate tirzepatide's effects on endothelial proliferation, migration, and tube formation, alongside the activation of Akt, endothelial nitric oxide synthase (eNOS), and extracellular signal-regulated kinase 1/2 (ERK1/2) signaling, assessed by western blotting. Knockdown of GLP-1R or GIPR abrogated the pro-angiogenic effects of tirzepatide, while pharmacological inhibition of the Akt/eNOS or ERK1/2 pathways attenuated endothelial responses. In vivo, tirzepatide treatment significantly enhanced perfusion recovery and increased capillary density in the ischemic limbs of diabetic mice, corroborating its angiogenic effects. Collectively, these findings demonstrate that tirzepatide facilitates angiogenesis and accelerates ischemic limb revascularization through dual GLP-1R/GIPR activation and subsequent engagement of Akt/eNOS and ERK1/2 signaling pathways, highlighting its potential as a therapeutic strategy for diabetic CLI.