Biologie cellulaire de la prévention et du traitement des surdités neurosensorielles.

Abstract

Les surdites de perception se caracterisent, pour la plupart, par une atteinte de l' oreille interne, plus particulierement des cellules ciliees et des neurones auditifs. A l' heure actuelle, aucun traitement permettant de restaurer la fonction auditive ne peut etre propose. La regeneration des cellules ciliees de la portion auditive de l' oreille interne semble, dans le cas des mammiferes, limitee a la periode du developpement. Plusieurs facteurs de croissance tels l' acide retinoique, l' IGF, le TGFalpha ou l' EGF peuvent etre utilises pour stimuler la regeneration des cellules ciliees des mammiferes et/ou des neurones du ganglion spiral. Des facteurs trophiques et des piegeurs de radicaux libres protegent des effets toxiques medicamenteux sur les cellules ciliees (aminosides, derives du platine), les neurotrophines pourraient permettre le maintien de l' innervation de l' organe de Corti.

Perception deafness, as opposed to transmission deafness, results from a lesion of the sensory cells and/or of the neurons of the auditory part of inner ear. There is currently no treatment able to stop the progression of a hearing loss or to restore a lost auditory function. In this paper, we review the progress which has been made with respect to the regeneration and the protection of neurosensory structures in the inner ear. A spontaneous post-lesional regeneration of hair cells in the sensory epithelium has been observed in amphibians and birds as well as in the vestibular part of the mammalian inner ear. In contrast, hair cells regeneration in the auditory portion of the inner ear of mammals appears to be limited to the developmental stages. In this review, we discuss the biological mechanisms of this repair process. Several growth factors (such as retinoic acid, IGF, TGFbeta, EGF) might be useful to stimulate hair cell regeneration in mammalian inner ear. Otoprotection of the sensory epithelium is a therapeutical strategy aimed at preventing further degradation of the auditory function. The prevention of the deleterious effect on hair cells of several drugs such as aminoglycosides and platin derivatives has been obtained using free radical scavengers or growth factors. The maintenance of the connection between Corti's organ and the cochlear nucleus is essential to transfer the information to the central nervous system. Studies of the development of the innervation of the inner ear suggests the potential therapeutic interest of various growth factors, mostly the neurotrophins, to maintain the innervation of the adult Corti organ. [References: 38]