Antimicrobial peptide derived from insulin-like growth factor-binding protein 5 improves diabetic wound healing.

Impaired keratinocyte functions are major factors that are responsible for delayed diabetic wound healing. In addition to its antimicrobial activity, the antimicrobial peptide derived from insulin-like growth factor-binding protein 5 (AMP-IBP5) activates mast cells and promotes keratinocyte and fibroblast proliferation and migration. However, its effects on diabetic wound healing remain unclear. Human keratinocytes were cultured in normal or high glucose milieus. The production of angiogenic growth factor and cell proliferation and migration were evaluated. Wounds in normal and streptozotocin-induced diabetic mice were monitored and histologically examined. We found that AMP-IBP5 rescued the high glucose-induced attenuation of proliferation and migration as well as the production of angiogenin and vascular endothelial growth factors in keratinocytes. The AMP-IBP5-induced activity was mediated by the epidermal growth factor receptor, signal transducer and activator of transcription 1 and 3, and mitogen-activated protein kinase pathways, as indicated by the inhibitory effects of pathway-specific inhibitors. In vivo, AMP-IBP5 markedly accelerated wound healing, increased the expression of angiogenic factors and promoted vessel formation in both normal and diabetic mice. Overall, the finding that AMP-IBP5 accelerated diabetic wound healing by protecting against glucotoxicity and promoting angiogenesis suggests that AMP-IBP5 might be a potential therapeutic target for treating chronic diabetic wounds.

Topical Gynura procumbens as a Novel Therapeutic Improves Wound Healing in Diabetic Mice.

Nonhealing wounds are major socioeconomic challenges to healthcare systems worldwide. Therefore, there is a substantially unmet need to develop new drugs for wound healing. Gynura procumbens, a herb found in Southeast Asia, may be an effective therapeutic for nonhealing diabetic wounds. The aim of this study was to evaluate the efficacy of G. procumbens on wound healing in the diabetic milieu. G. procumbens extract was obtained using 95% ethanol and its components were determined by thin layer chromatography. Diabetes was induced in mice using streptozotocin. We found that G. procumbens extract contained stigmasterol, kaempferol and quercetin compounds. Topical application of G. procumbens on the wounded skin of diabetic mice accelerated wound healing and induced the expression of angiogenin, epidermal growth factor, fibroblast growth factor, transforming growth factor and vascular endothelial growth factor. Furthermore, G. procumbens promoted in vitro wound healing and enhanced the migration and/or proliferation of human endothelial cells, fibroblasts, keratinocytes and mast cells cultured in diabetic conditions. Finally, G. procumbens promoted vascular formation in the diabetic mice. To the best of our knowledge, this is the first study that evaluates in vivo wound healing activities of G. procumbens and activation of cells involved in wound healing process in diabetic conditions. The findings that G. procumbens accelerates wound healing and activates cells involved in the wound healing process suggest that G. procumbens might be an effective alternative therapeutic option for nonhealing diabetic wounds.