Browsing by Subject "Hair cells"

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    Cell- and gene-therapy approaches to inner ear repair
    (F. Hernández y J.F. Madrid. Murcia: Universidad de Murcia, Departamento de Biología Celular e Histología., 2011) Conde de Felipe, M.M.; Feijoo Redondo, A.; García-Sancho, J.; Schimmang, T.; Durán Alonso, M.B.
    Sensorineural hearing loss is the most common sensory disorder in humans. It is primarily due to the degeneration of highly specialised mechanosensory cells in the cochlea, the so-called hair cells. Hearing problems can also be caused or further aggravated by the death of auditory sensory neurons that convey the information from the hair cells to the brain stem. Despite the discovery of stem/progenitor cells in the mammalian cochlea, no regeneration of either damaged hair cells or auditory neurons has been observed in mammals, in contrast to what is seen in avians and non-mammalian vertebrates. The reasons for this divergence have not yet been elucidated, although loss of stem cells and/or loss of their phenotypic plasticity in adult mammals have been put forward as possible explanations. Given the high incidence of this disorder and its economic and social implications, a considerable number of research lines have been set up aimed towards the regeneration of cochlear sensory cell types. This review summarizes the various routes that have been explored, ranging from the genetic modification of endogenous cells remaining in the inner ear in order to promote their transdifferentiation, to the implantation of exogenous stem or progenitor cells and their subsequent differentiation within the host tissue. Prophylactic treatments to fight against progressive sensory cell degeneration in the inner ear are also discussed.
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    Characterization of the early pathology of cochlear stereocilia in four inbred mouse strains with progressive hearing loss
    (Universidad de Murcia. Departamento de Biología Celular e Histología, 2019) Liu, Xiang; Xie, Yi; Huang, Shanshan; Xu, Ang; Zhao, Mengmeng; Kang, Xiaoxia; Yan, Aiwei; Li, Ping; Jin, Changzhu; Han, Fengchan
    Objective. Inbred strains of mice offer promising models for understanding the genetic basis of age-related hearing loss (AHL). NOD/LtJ, A/J, DBA/2J and C57BL/6J mice are classical models of age-related hearing loss and exhibit early onset of pathology of AHL. This study was carried out to characterize the early pathology of cochlear stereocilia in the four mouse strains with age-related hearing loss. Methods. The structural features of stereocilia in NOD/LtJ, A/J, DBA/2J and C57BL/6J mice were observed by scanning electron microscopy (SEM) at age of 2, 4, 6 or 8, and 10 or 12 weeks. Meanwhile, auditoryevoked brainstem response (ABR) and distortion product otoacoustic emission (DPOAE) amplitudes of the mice were measured at various intervals (3, 4, 6, 8, 10 and 12 weeks of age). Results. The ABR thresholds in NOD/LtJ, A/J and DBA/2J mice increased with age from 3 to 12 weeks. DPOAE amplitudes in NOD/LtJ, A/J, DBA/2J mice were very low at 4 weeks and became negative at 8 weeks at f2 frequency of 17 672 Hz. In addition to the progressive hearing loss, the four mouse strains displayed early onset (at 2 weeks of age) and progressive degeneration of stereocilia in hair cells. Conclusion. Early degeneration of stereocilia contributes to the functional impairment of hair cells and hearing loss in NOD/LtJ, A/J, DBA/2J and C57BL/6J mice.