Les kératinocytes : des cellules non neuronales impliquées dans la douleur

Keratinocytes are not only the constituent elements of a passive barrier for organism protection. These non neuronal cells are real sensors that are able to be activated by physical or chemical stimulations issued from their environment, as well as respond by emitting chemical signals addressed to adjacent sensory neurons. That way, they have a part in painful information genesis. Keratinocytes play an important part in pain development, whatever its origin: inflammation, bone fracture, nevroma. NGF is an important factor secreted at high levels by keratinocytes to exacerbate inflammatory lesions, at least in part. Epidermal keratinocytes contain a variety of sensory and information transmission systems. Thus, the traditional view of the sensory system in the skin, focusing on peripheral sensory fibres as the sensor, can no longer be admitted. Considering all data presented in this review, epidermal keratinocytes could be considered at the “forefront” of the body's sensory system, able to detect information coming from their own environment, and to generate information transmitted to peripheral sensory fibres innervating epidermal tissue. Signals consecutive to environmental factor variations are processed in the epidermis, and may influence, via central and peripheral nervous systems, emotional states such as pain.