Effects of topical application of CHF6467, a mutated form of human nerve growth factor, on skin wound healing in diabetic mice.

Nerve growth factor (NGF) is the protein responsible for the development and maintenance of sensory skin innervation. Given the role of an appropriate innervation in skin healing, NGF has been indicated as a possible pro-healing treatment in pathological conditions characterized by nerve ending loss, such as chronic ulcers in diabetes. However, the use of NGF as a therapeutic agent is limited by its hyperalgesic effect. We tested the effect of topical application of the non-algogenic NGF derivative in two models of skin ulcer induced in diabetic mice dbdb Healing time, repaired skin histology, reinnervation and angiogenesis were investigated using morphological and molecular approaches. In this study we showed that the topical administration of CHF6467, a recombinant human NGF in which an aminoacid substitution (R100E) abolished hyperalgesic effect, accelerates skin repair in experimental wounds (full excision and pressure ulcer) induced in diabetic mice (dbdb). CHF6467-induced acceleration of wound healing was accompanied by increased reepithelization, reinnervation and revascularization, as assessed by histology, immunohistochemistry and image analysis. Bioinformatic analysis of differentially expressed genes and signaling pathways in the wound tissues showed that AKT-mTOR was the most regulated pathway. In spite of the transdermal absorption leading to measurable, dose-dependent increases in CHF6467 plasma levels, no systemic thermal or local mechanical hyperalgesia was observed in treated mice. When tested in vitro in human cell lines, CHF6467 stimulated keratinocyte and fibroblast proliferation and tube formation by endothelial cells. Collectively, these results support a possible use of CHF6467 as a pro-healing agent in skin lesions in diabetes. Significance Statement The topic application of CHF6467, a mutated form of NGF with without hyperalgic effects, accelerates re-innervation, neoangiogenesis and wound healing in diabetic mice in both full skin excision and pressur ulcer model though Akt/mTOR pathway and does not induce hyperalgesia.