Substance P and thiorphan synergically enhance angiogenesis in wound healing

Impaired angiogenesis is a common pathological characteristic of chronic wounds. Therefore, the regulation of angiogenesis is important for proper tissue repair. It was reported that substance P (SP) accelerates wound healing in a skin injury model. SP is degraded by neutral endopeptidase (NEP). Our study shows that systemic co-treatment of SP and thiorphan, an inhibitor of NEP synergically increased the number of α-smooth muscle actin positive-blood vessels in skin wounds. However, there was no synergic improvement in wound contraction and extracellular matrix deposition. Therefore, inhibition of endogenous NEP activity by thiorphan treatment might modulate the effects of SP treatment specifically on accelerating angiogenesis during wound healing. However, the molecular mechanism(s) of the synergic increase in angiogenesis by SP and thiorphan treatment is still unknown.