scholarly journals Research Progress on Flat Epithelium of the Inner Ear

2020 ◽  
pp. 775-785
Author(s):  
L HE ◽  
J-Y GUO ◽  
K LIU ◽  
G-P WANG ◽  
S-S GONG

Sensorineural hearing loss and vertigo, resulting from lesions in the sensory epithelium of the inner ear, have a high incidence worldwide. The sensory epithelium of the inner ear may exhibit extreme degeneration and is transformed to flat epithelium (FE) in humans and mice with profound sensorineural hearing loss and/or vertigo. Various factors, including ototoxic drugs, noise exposure, aging, and genetic defects, can induce FE. Both hair cells and supporting cells are severely damaged in FE, and the normal cytoarchitecture of the sensory epithelium is replaced by a monolayer of very thin, flat cells of irregular contour. The pathophysiologic mechanism of FE is unclear but involves robust cell division. The cellular origin of flat cells in FE is heterogeneous; they may be transformed from supporting cells that have lost some features of supporting cells (dedifferentiation) or may have migrated from the flanking region. The epithelial-mesenchymal transition may play an important role in this process. The treatment of FE is challenging given the severe degeneration and loss of both hair cells and supporting cells. Cochlear implant or vestibular prosthesis implantation, gene therapy, and stem cell therapy show promise for the treatment of FE, although many challenges remain to be overcome.

2020 ◽  
Vol 12 (1) ◽  
pp. 59
Author(s):  
Diana Kusuma Wardhani ◽  
Jojok Mukono Mukono

Introduction: As one of the preferred modes of land transportation, the frequency of train services was very high. One of the negative impacts arising from train activity was noise. The high noise intensity of the train causes hearing loss. Method: This study aims to analyze the differences in the incidence of hearing loss in 2 groups of residents in Turirejo Lawang Malang. This research used the observational method and the data were analyzed descriptive qualitative. A total of 20 people were selected as respondents by purposive sampling. Noise intensity was measured by Sound Level Meter and audiometric measurements were examined at SIMA Malang Laboratory. Result and Discussion: The prevalence of sensorineural hearing loss was more common in residents whose homes at 3-7 m away from the railroad tracks. In addition, residents who lived at least 15 years at a distance of 3-7 m also experienced more hearing loss. One cause of hearing loss is due to exposure to high noise and for a long time and will damage the hair cells in the cochlea, causing hearing loss. If noise exposure continues and for a long period of time damage to hair cells will be permanent and cannot return to normal. Conclusion: There needs to be a policy from the government in determining the minimum limit of the distance of the house to the railroad tracks. In addition, it is necessary to install a barrier near people’s homes to reduce noise.


2021 ◽  
Vol 15 ◽  
Author(s):  
Lingna Guo ◽  
Wei Cao ◽  
Yuguang Niu ◽  
Shuangba He ◽  
Renjie Chai ◽  
...  

Inner ear hair cells (HCs) and spiral ganglion neurons (SGNs) are the core components of the auditory system. However, they are vulnerable to genetic defects, noise exposure, ototoxic drugs and aging, and loss or damage of HCs and SGNs results in permanent hearing loss due to their limited capacity for spontaneous regeneration in mammals. Many efforts have been made to combat hearing loss including cochlear implants, HC regeneration, gene therapy, and antioxidant drugs. Here we review the role of autophagy in sensorineural hearing loss and the potential targets related to autophagy for the treatment of hearing loss.


2020 ◽  
pp. jmedgenet-2020-106892
Author(s):  
Xue Gao ◽  
Sha-Sha Huang ◽  
Shi-Wei Qiu ◽  
Yu Su ◽  
Wei-Qian Wang ◽  
...  

BackgroundGermline variants in PTPN11 are the primary cause of Noonan syndrome with multiple lentigines (NSML) and Noonan syndrome (NS), which share common skin and facial symptoms, cardiac anomalies and retardation of growth. Hearing loss is considered an infrequent feature in patients with NSML/NS. However, in our cohort, we identified a group of patients with PTPN11 pathogenic variants that were primarily manifested in congenital sensorineural hearing loss (SNHL). This study evaluated the incidence of PTPN11-related NSML or NS in patients with congenital SNHL and explored the expression of PTPN11 and the underlying mechanisms in the auditory system.MethodsA total of 1502 patients with congenital SNHL were enrolled. Detailed phenotype-genotype correlations were analysed in patients with PTPN11 variants. Immunolabelling of Ptpn11 was performed in P35 mice. Zebrafish with Ptpn11 knockdown/mutant overexpression were constructed to further explore mechanism underlying the phenotypes.ResultsTen NSML/NS probands were diagnosed via the identification of pathogenic variants of PTPN11, which accounted for ~0.67% of the congenital SNHL cases. In mice cochlea, Shp2, which is encoded by Ptpn11, is distributed in the spiral ganglion neurons, hair cells and supporting cells of the inner ear. In zebrafish, knockdown of ptpn11a and overexpression of mutant PTPN11 were associated with a significant decrease in hair cells and supporting cells. We concluded that congenital SNHL could be a major symptom in PTPN11-associated NSML or NS. Other features may be mild, especially in children.ConclusionScreening for PTPN11 in patients with congenital hearing loss and variant-based diagnoses are recommended.


2021 ◽  
Vol 15 ◽  
Author(s):  
Shan Xu ◽  
Ning Yang

Mammalian inner ear hair cells do not have the ability to spontaneously regenerate, so their irreversible damage is the main cause of sensorineural hearing loss. The damage and loss of hair cells are mainly caused by factors such as aging, infection, genetic factors, hypoxia, autoimmune diseases, ototoxic drugs, or noise exposure. In recent years, research on the regeneration and functional recovery of mammalian auditory hair cells has attracted more and more attention in the field of auditory research. How to regenerate and protect hair cells or auditory neurons through biological methods and rebuild auditory circuits and functions are key scientific issues that need to be resolved in this field. This review mainly summarizes and discusses the recent research progress in gene therapy and molecular mechanisms related to hair cell regeneration in the field of sensorineural hearing loss.


2021 ◽  
Vol 2021 ◽  
pp. 1-14
Author(s):  
Xiaochang Zhao ◽  
Heidi J. Henderson ◽  
Tianying Wang ◽  
Bo Liu ◽  
Yi Li

Hearing loss is a debilitating disease that affects 10% of adults worldwide. Most sensorineural hearing loss is caused by the loss of mechanosensitive hair cells in the cochlea, often due to aging, noise, and ototoxic drugs. The identification of genes that can be targeted to slow aging and reduce the vulnerability of hair cells to insults is critical for the prevention of sensorineural hearing loss. Our previous cell-specific transcriptome analysis of adult cochlear hair cells and supporting cells showed that Clu, encoding a secreted chaperone that is involved in several basic biological events, such as cell death, tumor progression, and neurodegenerative disorders, is expressed in hair cells and supporting cells. We generated Clu-null mice (C57BL/6) to investigate its role in the organ of Corti, the sensory epithelium responsible for hearing in the mammalian cochlea. We showed that the deletion of Clu did not affect the development of hair cells and supporting cells; hair cells and supporting cells appeared normal at 1 month of age. Auditory function tests showed that Clu-null mice had hearing thresholds comparable to those of wild-type littermates before 3 months of age. Interestingly, Clu-null mice displayed less hair cell and hearing loss compared to their wildtype littermates after 3 months. Furthermore, the deletion of Clu is protected against aminoglycoside-induced hair cell loss in both in vivo and in vitro models. Our findings suggested that the inhibition of Clu expression could represent a potential therapeutic strategy for the alleviation of age-related and ototoxic drug-induced hearing loss.


2020 ◽  
Vol 2020 ◽  
pp. 1-10
Author(s):  
Muhammad Waqas ◽  
Iram Us-Salam ◽  
Zainab Bibi ◽  
Yunfeng Wang ◽  
He Li ◽  
...  

The hair cells that reside in the cochlear sensory epithelium are the fundamental sensory structures responsible for understanding the mechanical sound waves evoked in the environment. The intense damage to these sensory structures may result in permanent hearing loss. The present strategies to rehabilitate the hearing function include either hearing aids or cochlear implants that may recover the hearing capability of deaf patients to a limited extent. Therefore, much attention has been paid on developing regenerative therapies to regenerate/replace the lost hair cells to treat the damaged cochlear sensory epithelium. The stem cell therapy is a promising approach to develop the functional hair cells and neuronal cells from endogenous and exogenous stem cell pool to recover hearing loss. In this review, we specifically discuss the potential of different kinds of stem cells that hold the potential to restore sensorineural hearing loss in mammals and comprehensively explain the current therapeutic applications of stem cells in both the human and mouse inner ear to regenerate/replace the lost hair cells and spiral ganglion neurons.


2012 ◽  
Vol 9 (3) ◽  
pp. 231-242 ◽  
Author(s):  
Teresa Rivera ◽  
Lorena Sanz ◽  
Guadalupe Camarero ◽  
Isabel Varela-Nieto

1993 ◽  
Vol 21 (4) ◽  
pp. 192-196 ◽  
Author(s):  
Aytac Saraçaydin ◽  
Sedat Katircioğlu ◽  
Sami Katircioğlu ◽  
M Can Karatay

A total of twelve patients with a relatively uncommon form of progressive sensorineural deafness (autoimmune innerear disease) were treated orally with 1 mg/kg azathioprine, once daily, and with 30 mg prednisolone, every other day, for 4 weeks. Statistically significant increases in the ability to hear pure tones or in discrimination on audiometry took place in 10/12 patients. This condition was initially described as ‘sensorineural hearing loss', but it is now clear that the term ‘autoimmune inner-ear disease’ is more appropriate since the vestibular compartment as well as the cochlear compartment is involved. This relatively uncommon disease is one of the few forms of sensorineural deafness that can be successfully treated.


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