The sensory organs responsible of hearing and balance have a common embryonic origin in the otic placode. Lineages of neural, sensory and support cells are generated from common otic neuroepithelial progenitors. The sequential generation of the cell types that will structure the adult inner ear requires the dynamic coordination of cell proliferation with cell differentiation programs; as well as the strict regulation of cell survival, apoptosis, autophagy and senescence to refine cell numbers and sculpt the organs. A network of intracellular signals orchestrates the transcriptional response to the extracellular input. Understanding the molecular clues that direct otic development is fundamental for the design of novel strategies for the protection and repair of hearing loss (HL) and balance disorders. Some forms of genetic HL are rare diseases, in striking contrast, presbyacusis, affects approximately half of the population over 60 years old. HL occurs when the sensory cells and neurons of the cochlea degenerate and die. Genetic and environmental factors contribute to the progression of HL, being noise the main environmental noxious agent for human hearing. There is no restorative treatment for deafness but functional replacement by means of prosthesis. Therefore, prevention and treatment of HL is an unmet medical need. The described pathophysiological mechanisms involved in HL include oxidative stress, excitotoxicity and inflammation, resulting in synaptic loss, axonal degeneration, and apoptosis of spiral ganglion neurons. These mechanisms are shared with other neurodegenerative disorders. Neuroinflammation is an essential element in the progression of injury and cell loss, and a target for cell protection strategies. Autophagy and senescence are cellular processes involved in development and ageing, whose contribution to inner ear structures and functions will be discussed in the context of their regulation by IGF-1.

Video de la presentación realizada en el Simposio Internacional: "Hipoacusias hereditarias: del diagnóstico a la terapia", celebrado en Madrid (España) los días 5 y 6 de marzo de 2015.

Peer Reviewed