Stem Cell Differentiation Stage Factors (SCDSFs) Taken from Zebrafish Embryo during Organogenesis and their Role as Epigenetics Regulators able to Reverse Neurosensory Hearing Loss

Hearing loss, the most common form of human sensory deficit, is the partial or total inability to hear sound in one or both ears. It may be a sudden or a progressive impairment that gradually gets worse over time. Depending on the cause, it can be mild or severe, temporary or permanent. It may be a bilateral loss occurring in both ears or unilateral. Hearing loss may be fluctuating, that is, varying over improving at times and getting worse at other times. In other cases, hearing loss is stable, not changing at all with time. Hearing loss is caused by many factors, including genetics, age, exposure to noise, illness, chemicals, and physical trauma. Hearing loss may affect all ages, delaying speech and learning in children, and causing social and vocational problems for adults. 1 Hearing dysfunctions can be classified by type, degree, configuration, time of onset, etiology, and finally, consequences on speech development. They can be divided into conductive, mixed, central types and neuro sensory hearing loss 2. Conductive hearing loss results from interference with the mechanical transmission of sound through the external and middle ear; it can be congenital, as a consequence of anatomic abnormalities, but it can commonly be acquired following middle ear inflammatory pathologies. Neuro sensory hearing loss results from failure to transduce vibrations to neural impulses in the cochlea and usually is a consequence of an irreversible damage to the differentiated cells which make up the organ of hearing and the acoustic paths at various levels.