Diabetic neuropathy plays an important role in the development of chronic wounds. Endothelial progenitor cells (EPCs) are known important regulators of wound angiogenesis. However, the role of neuropeptides in EPC function, and particularly Neurotensin (NT), is unknown in diabetic wound healing. EPCs isolated from normal mice were cultured in high glucose (25 mM) or normoglicemia (5.5 mM) and treated with NT (25-400 nM) for 3 days. Moreover, EPCs isolated from streptozotocin (STZ)-induced diabetic mice were treated with NT (100 nM) for 3 days. Subsequently, EPC viability, cell adhesion and reactive oxygen species (ROS) levels were evaluated. To the in vivo wound healing model, 6 mm wounds were created in the dorsum of diabetic mice and wound progression was followed up to day 10. The wound edges were injected with ex-vivo diabetic bone marrow derived EPCs treated in culture with NT (100 nM) for 3 days, or EPCs without NT treatment, or vehicle. Angiogenesis was evaluated by immunohistochemistry. The viability of EPCs cultured under high glucose or EPCs from diabetic mice was improved by NT treatment. Also, EPCs from diabetic mice showed decreased adhesion (58% of control, p<0.05) and increased ROS levels (148% of control, p<0.05) when compared to control EPCs, and these effects were reversed by NT treatment. In addition, NT-treated EPCs, from diabetic mice, improved wound closure (day 10, 4% of original wound size) when compared with non-treated EPCs or vehicle (day 10, 32% and 35% of original wound size, respectively, p<0.05). Furthermore, NT-treated EPCs, from diabetic mice, increased neovascularization at the wound site (153% of vehicle, p<0.05) when compared with non-treated EPCs (115% of vehicle) or vehicle. These results show that neurotensin is able to improve the function of EPCs from diabetic animals, which are able to improve wound healing by promoting angiogenesis. The restoration of EPC function by neurotensin could improve their therapeutic effect for the treatment of chronic diabetic wounds.
E.C. Leal: None. A. Figueiredo: None. E. Carvalho: None.
Portuguese Foundation for Science and Technology; European Foundation for the Study of Diabetes; Portuguese Society of Diabetology