654 Stimulation and Protection of Cutaneous Sensory Neuron System induced by Forest Honey from Ikaria Island

Abstract

Sensory innervation involves nerve endings which are located in dermis and epidermis, reaching the uppermost viable layer of skin. Cutaneous innervation is closely linked with major skin functions and contributes to skin homeostasis. Wound-healing, repair process, sense of touch, perception of thermal stimuli as well as intra-epidermal nerve fibre density on face decrease with aging and are associated with changes in neuronal functions and structures. For centuries, honey has been utilized for wound healing purposes but recently, information regarding honey’s mechanisms of action on wound healing and as a therapeutic agent for skin disorders has accumulated at a rapid pace. However, each honey is very specific especially due to the surrounding flora and bee strains associated. Our previous studies have shown that all honeys were not equivalent and consequently, they did not induce the same biological activities. For counteracting the alteration of sensory innervation system, we studied the activities of a forest honey from Ikaria Island (FHII) on a new human sensory neurons 2D model. Human sensory neurons derived from human induced pluripotent cells were co-cultured with human keratinocytes. After treatment by FHII for 10 days; the numbers of neurons, the growth of neurites and the expression of TrkA (NGF receptor) and mu-opioid receptors (MOR), which are four key parameters for sensory neuron homeostasis, were studied by immunocytofluorescence. We have observed that treatment by FHII did not induce neurone proliferation but significantly stimulated by 30% the growth of neurites and the increase of TrkA and MOR expressions by +38% and +45% respectively. These results indicate that FHII stimulates the development of neuronal network, protects its functionalities and suggest a beta-endorphin-like activity of this natural compound making this forest honey from Ikaria island a good candidate for maintaining homeostasis of human cutaneous sensory neuron system and skin.