Histopathological Observations on the Cochlear Changes in Otosclerosis

1977 ◽  
Vol 86 (6) ◽  
pp. 813-820 ◽  
Author(s):  
F. Antoli-Candela ◽  
T. McGill ◽  
D. Peron
Keyword(s):  
Hearing Loss ◽  
Hair Cell ◽  
Sensorineural Hearing Loss ◽  
Cell Population ◽  
Basilar Membrane ◽  
Stria Vascularis ◽  
Spiral Ligament ◽  
Age Group ◽  
Histopathological Findings ◽  
Temporal Bones

Alterations in the dimensions of the basilar membrane and spiral ligament have been implicated in the pathogenesis of sensorineural hearing loss in otosclerosis. The histopathological findings in nineteen temporal bones with otosclerotic involvement of the cochlear endosteum are reviewed. Hyalinization and decrease in the width of the spiral ligament are the only consistent findings related to the otosclerotic focus in these temporal bones. The width of the basilar membrane is normal. The hair cell population and the stria vascularis are normal for the age group.

Mechanisms of hearing loss and cell death in the cochlea of connexin mutant mice

2020 ◽  
Vol 319 (3) ◽  
pp. C569-C578
Author(s):  
Bei Chen ◽  
Hongen Xu ◽  
Yanfang Mi ◽  
Wei Jiang ◽  
Dan Guo ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Hearing Loss ◽  
Hair Cell ◽  
Stria Vascularis ◽  
Reactive Oxygen Species Generation ◽  
Cell Loss ◽  
Outer Hair Cells ◽  
Spiral Ligament ◽  
Hair Cell Loss ◽  
Auditory Brain Stem Response

Mutations in connexin 30 (Cx30) are known to cause severe congenital hearing impairment; however, the mechanism by which Cx30 mediates homeostasis of endocochlear gap junctions is unclear. We used a gene deletion mouse model to explore the mechanisms of Cx30 in preventing hearing loss. Our results suggest that despite severe loss of the auditory brain-stem response and endocochlear potential at postnatal day 18, Cx30−/− mice only show sporadic loss of the outer hair cells. This inconsistency in the time course and severity of hearing and hair cell losses in Cx30−/− mice might be explained, in part, by an increase in reactive oxygen species generation beginning at postnatal day 10. The expression of oxidative stress genes was increased in Cx30−/− mice in the stria vascularis, spiral ligament, and organ of Corti. Furthermore, Cx30 deficiency caused mitochondrial dysfunction at postnatal day 18, as assessed by decreased ATP levels and decreased expression of mitochondrial complex I proteins, especially in the stria vascularis. Proteomic analysis further identified 444 proteins that were dysregulated in Cx30−/− mice, including several that are involved in mitochondria electron transport, ATP synthesis, or ion transport. Additionally, proapoptotic proteins, including Bax, Bad, and caspase-3, were upregulated at postnatal day 18, providing a molecular basis to explain the loss of hearing that occurs before hair cell loss. Therefore, our results are consistent with an environment of oxidative stress and mitochondrial damage in the cochlea of Cx30−/− mice that is coincident with hearing loss but precedes hair cell loss.

Comparative Measurements of Cochlear Apparatus

1968 ◽  
Vol 11 (2) ◽  
pp. 229-235 ◽  
Author(s):  
Makoto Igarashi ◽  
Robert G. Mahon ◽  
Shizuo Konishi
Keyword(s):  
Cross Section ◽  
Basilar Membrane ◽  
Stria Vascularis ◽  
The Other ◽  
Tectorial Membrane ◽  
Spiral Ligament ◽  
Scala Tympani ◽  
Basal Turn ◽  
Temporal Bones ◽  
Scala Vestibuli

Micromeasurements of horizontal midmodiolar sections of temporal bones were performed to obtain the dimensions of the different cochlear partitions in the squirrel monkey, the cat, and the rat. The width of the basilar membrane and the tectorial membrane were larger in the apical turn than in the basal turn in all three species. The thickness of the spiral ligament, the width of Reissner’s membrane, and the width of the stria vascularis were larger in the basal turn than in the apical turn. The cross-section areas of scala vestibuli and scala tympani in the three species were larger in the basal turn than in the other turns.

Sensorineural Hearing Loss due to Cochlear Otospongiosis: Theoretical Considerations of Etiology

1975 ◽  
Vol 84 (4) ◽  
pp. 544-551 ◽  
Author(s):  
Fred H. Linthicum ◽  
Roberto Filipo ◽  
Sidney Brody
Keyword(s):  
Hearing Loss ◽  
Sensorineural Hearing Loss ◽  
Inner Ear ◽  
Basilar Membrane ◽  
Stria Vascularis ◽  
Organ Of Corti ◽  
Sensorineural Hearing ◽  
Toxic Substances ◽  
Theoretical Considerations

Several theories have been advanced to explain the sensorineural hearing loss that occurs in patients with otospongiosis: toxic substances produced by the otospongiotic focus; vascular shunts between the inner ear vessels and the otospongiotic focus; and atrophy of the organ of Corti and stria vascularis due to unknown causes. Presented here is yet another theory: impingement upon the cochlear walls by the otospongiotic focus, causing a narrowing of the lumen of the cochlea and distortion of the basilar membrane.

Connexin 26 Immunohistochemistry in Temporal Bones With Cochlear Otosclerosis

2018 ◽  
Vol 127 (8) ◽  
pp. 536-542 ◽  
Author(s):  
Mia E. Miller ◽  
Ivan A. Lopez ◽  
Fred H. Linthicum ◽  
Akira Ishiyama
Keyword(s):  
Hearing Loss ◽  
Stria Vascularis ◽  
Organ Of Corti ◽  
Connexin 26 ◽  
Spiral Ligament ◽  
Mixed Hearing Loss ◽  
Cell Counts ◽  
Normal Hair ◽  
Connexin 30 ◽  
Temporal Bones

Hypothesis: Connexin-26 (Cx26) expression is diminished in the spiral ligament of subjects with hearing loss and cochlear otosclerosis (CO). Background: Human temporal bone (HTB) studies have demonstrated that CO is associated with hyalinization of the spiral ligament. We hypothesize that hyalinization is associated with a loss of fibrocytes with a consequent decline in Cx26 expression. Cx26 and Connexin-30 (Cx30) encode gap junction proteins expressed in supporting cells of the organ of Corti, the spiral limbus, stria vascularis, and in fibrocytes of the spiral ligament. These gap junctions are critical for potassium recycling and maintenance of the endocochlear potential. Diminished expression of these proteins would likely be associated with hearing dysfunction. Methods: Histopathology and clinical characteristics of 45 HTB specimens with CO and spiral ligament hyalinization were reviewed. Those with sensorineural or mixed hearing loss but normal or near-normal hair cell counts were analyzed with light microscopy, and Cx26-immunoreactive (IR) signal was qualitatively assessed. Results: H&E staining demonstrated hyalinization in the spiral ligament and loss of type II and type III fibrocytes. Cx26-IR was diminished throughout the cochlea affected with CO compared with normal controls. Conclusions: Cx26-IR reduction in the spiral ligament of subjects with CO likely plays a role in hearing loss.

scholarly journals Experimental estrogen-induced hyperprolactinemia results in bone-related hearing loss in the guinea pig

2007 ◽  
Vol 293 (5) ◽  
pp. E1224-E1232 ◽  
Author(s):  
Kathleen C. Horner ◽  
Yves Cazals ◽  
Régis Guieu ◽  
Marc Lenoir ◽  
Nicole Sauze
Keyword(s):  
Hearing Loss ◽  
Hair Cell ◽  
Inner Ear ◽  
Stria Vascularis ◽  
Compound Action Potential ◽  
Spiral Ligament ◽  
Functional Studies ◽  
Fischer 344 ◽  
Inner Ear Dysfunction ◽  
Cryostat Sections

Our group (Horner KC, Guieu R, Magnan J, Chays A, Cazals Y. Neuropsychopharmacology 26: 135–138, 2002) has earlier described hyperprolactinemia in some patients presenting inner ear dysfunction. However, in that study, it was not possible to determine whether hyperprolactinemia was a cause or an effect of the symptoms. To investigate the effect of hyperprolactinemia on inner ear function, we first developed a model of hyperprolactinemia in estrogen-primed Fischer 344 rats and then performed functional studies on pigmented guinea pigs. Hyperprolactinemia induced, after 2 mo, a hearing loss of ∼30–40 dB across all frequencies, as indicated by the compound action potential audiogram. During the 3rd mo, the hearing loss continued to deteriorate. The threshold shifts were more substantial in males than in females. Observations under a dissection microscope revealed bone dysmorphology of the bulla and the cochlea. Light microscopy observations of cryostat sections confirmed bone-related pathology of the bony cochlear bulla and the cochlear wall and revealed morphopathology of the stria vascularis and spiral ligament. Scanning electron microscopy revealed loss of hair cells and stereocilia damage, in particular in the upper three cochlear turns and the two outermost hair cell rows. The data provide the first evidence of otic capsule and hair cell pathology associated with estrogen-induced prolonged hyperprolactinemia and suggest that conditions such as pregnancy, anti-psychotic drug treatment, aging, and/or stress might lead to similar ear dysfunctions.

scholarly journals Prevention of acquired sensorineural hearing loss in mice by in vivo Htra2 gene editing

2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Xi Gu ◽  
Daqi Wang ◽  
Zhijiao Xu ◽  
Jinghan Wang ◽  
Luo Guo ◽  
...  
Keyword(s):  
Hearing Loss ◽  
Protective Effect ◽  
Hair Cell ◽  
Sensorineural Hearing Loss ◽  
Auditory Brainstem Response ◽  
Gene Editing ◽  
Auditory Brainstem ◽  
Sensorineural Hearing ◽  
Brainstem Response

Abstract Background Aging, noise, infection, and ototoxic drugs are the major causes of human acquired sensorineural hearing loss, but treatment options are limited. CRISPR/Cas9 technology has tremendous potential to become a new therapeutic modality for acquired non-inherited sensorineural hearing loss. Here, we develop CRISPR/Cas9 strategies to prevent aminoglycoside-induced deafness, a common type of acquired non-inherited sensorineural hearing loss, via disrupting the Htra2 gene in the inner ear which is involved in apoptosis but has not been investigated in cochlear hair cell protection. Results The results indicate that adeno-associated virus (AAV)-mediated delivery of CRISPR/SpCas9 system ameliorates neomycin-induced apoptosis, promotes hair cell survival, and significantly improves hearing function in neomycin-treated mice. The protective effect of the AAV–CRISPR/Cas9 system in vivo is sustained up to 8 weeks after neomycin exposure. For more efficient delivery of the whole CRISPR/Cas9 system, we also explore the AAV–CRISPR/SaCas9 system to prevent neomycin-induced deafness. The in vivo editing efficiency of the SaCas9 system is 1.73% on average. We observed significant improvement in auditory brainstem response thresholds in the injected ears compared with the non-injected ears. At 4 weeks after neomycin exposure, the protective effect of the AAV–CRISPR/SaCas9 system is still obvious, with the improvement in auditory brainstem response threshold up to 50 dB at 8 kHz. Conclusions These findings demonstrate the safe and effective prevention of aminoglycoside-induced deafness via Htra2 gene editing and support further development of the CRISPR/Cas9 technology in the treatment of non-inherited hearing loss as well as other non-inherited diseases.

Causes and Types of Sensorineural Hearing Loss. Clinical Manifestations and Basic Principles of Treatment

2020 ◽  
pp. 9-16
Author(s):  
Sergey Armakov
Keyword(s):  
Hearing Loss ◽  
Sensorineural Hearing Loss ◽  
Inner Ear ◽  
Clinical Manifestations ◽  
Sensorineural Hearing ◽  
Doppler Imaging ◽  
Comprehensive Treatment ◽  
Impaired Hearing ◽  
Temporal Bones ◽  
The Brain

Sensorineural hearing loss is a disorder associated with the damage to the inner ear structures: the cochlea (cortical organ), dysfunctioning of the vestibule-cochlear nerve or the central part of the auditory analyser (brain stem and cortical representation of the cortical temporal lobe). In recent years, there has been a steady increase in ensorineural hearing loss patients; they account for ca. 70% among the total patients with impaired hearing. The disease has numerous causes and a complex pathogenesis. Among the main factors contributing to hearing loss are genetic predisposition, perinatal pathology, including hypoxia at childbirth, exposure to infectious and toxic agents and metabolic disorders, injuries (mechanical, acoustic and altitude trauma). Vascular-rheological disorders in the vertebro-basilar system play an important part because blood is supplied to the inner ear from the anterior inferior cerebellar artery. There are sudden, acute and chronic sensorineural hearing loss. The ensorineural hearing loss isdiagnosed by examinations that allow to verify the diagnosis and to determine the sound analyser damage level. This complex includes audiometric examinations, including the tuning fork examination, speech audiometry, and acoustic impedancemetry. If necessary, ultrasound Doppler imaging of the main blood vessels of the brain, computed tomography of the temporal bones, and MRI of the brain are prescribed. The pattern of comprehensive treatment should include, first of all, the elimination of the disease cause and anti-hypoxic drugs, anti-oxidants and a number of physiotherapy procedures.

scholarly journals Noise-induced and age-related hearing loss:  new perspectives and potential therapies

F1000Research ◽  
2017 ◽  
Vol 6 ◽  
pp. 927 ◽  
Author(s):  
M Charles Liberman
Keyword(s):  
Hearing Loss ◽  
Hair Cell ◽  
Sensorineural Hearing Loss ◽  
Hair Cells ◽  
Auditory Nerve ◽  
Cell Loss ◽  
Sensorineural Hearing ◽  
Hair Cell Loss ◽  
Age Related ◽  
Age Related Hearing Loss

The classic view of sensorineural hearing loss has been that the primary damage targets are hair cells and that auditory nerve loss is typically secondary to hair cell degeneration. Recent work has challenged that view. In noise-induced hearing loss, exposures causing only reversible threshold shifts (and no hair cell loss) nevertheless cause permanent loss of >50% of the synaptic connections between hair cells and the auditory nerve. Similarly, in age-related hearing loss, degeneration of cochlear synapses precedes both hair cell loss and threshold elevation. This primary neural degeneration has remained a “hidden hearing loss” for two reasons: 1) the neuronal cell bodies survive for years despite loss of synaptic connection with hair cells, and 2) the degeneration is selective for auditory nerve fibers with high thresholds. Although not required for threshold detection when quiet, these high-threshold fibers are critical for hearing in noisy environments. Research suggests that primary neural degeneration is an important contributor to the perceptual handicap in sensorineural hearing loss, and it may be key to the generation of tinnitus and other associated perceptual anomalies. In cases where the hair cells survive, neurotrophin therapies can elicit neurite outgrowth from surviving auditory neurons and re-establishment of their peripheral synapses; thus, treatments may be on the horizon.

scholarly journals Using the Zebrafish Lateral Line to Understand the Roles of Mitochondria in Sensorineural Hearing Loss

2021 ◽  
Vol 8 ◽  
Author(s):  
Melanie Holmgren ◽  
Lavinia Sheets
Keyword(s):  
Cell Death ◽  
Hearing Loss ◽  
Hair Cell ◽  
Sensorineural Hearing Loss ◽  
Lateral Line ◽  
Hair Cells ◽  
High Energy ◽  
Sensorineural Hearing ◽  
Mitochondrial Activity ◽  
Ototoxic Drugs

Hair cells are the mechanosensory receptors of the inner ear and can be damaged by noise, aging, and ototoxic drugs. This damage often results in permanent sensorineural hearing loss. Hair cells have high energy demands and rely on mitochondria to produce ATP as well as contribute to intracellular calcium homeostasis. In addition to generating ATP, mitochondria produce reactive oxygen species, which can lead to oxidative stress, and regulate cell death pathways. Zebrafish lateral-line hair cells are structurally and functionally analogous to cochlear hair cells but are optically and pharmacologically accessible within an intact specimen, making the zebrafish a good model in which to study hair-cell mitochondrial activity. Moreover, the ease of genetic manipulation of zebrafish embryos allows for the study of mutations implicated in human deafness, as well as the generation of transgenic models to visualize mitochondrial calcium transients and mitochondrial activity in live organisms. Studies of the zebrafish lateral line have shown that variations in mitochondrial activity can predict hair-cell susceptibility to damage by aminoglycosides or noise exposure. In addition, antioxidants have been shown to protect against noise trauma and ototoxic drug–induced hair-cell death. In this review, we discuss the tools and findings of recent investigations into zebrafish hair-cell mitochondria and their involvement in cellular processes, both under homeostatic conditions and in response to noise or ototoxic drugs. The zebrafish lateral line is a valuable model in which to study the roles of mitochondria in hair-cell pathologies and to develop therapeutic strategies to prevent sensorineural hearing loss in humans.

Prevalence and classification of asymmetric forms of sensorineural hearing loss in older age group

2021 ◽  
Vol 20 (5) ◽  
pp. 8-12
Author(s):  
T. Yu. Vladimirova ◽  
◽  
A. B. Martynova ◽  
Keyword(s):  
Hearing Loss ◽  
Sensorineural Hearing Loss ◽  
Hearing Aids ◽  
Hearing Threshold ◽  
Older Age ◽  
Sensorineural Hearing ◽  
Age Group ◽  
The Difference ◽  
The Right

The significance of asymmetric sensorineural hearing loss (ASNHL) is due to a special approach to diagnosis, followed by the process of hearing aids and auditory rehabilitation. Currently, there is no standard audiometric criterion for determining the forms of asymmetry, which significantly affects the assessment of the prevalence of ASNHL. The study aimed to assess the prevalence and classification of ASNHL forms in the older age group using two methods of calculation: 1) the difference in the average hearing threshold at speech frequencies (in the range of 0,5–4 kHz) ≥15 dB was detected in 14,14% of cases; 2) the different degree of hearing loss, according to the International classification, in the right and left ear was 35,98%. In most cases, asymmetry was manifested by bilateral sensorineural hearing loss of varying severity, prevailing in the group of long-livers – 82,6%. Given the potentially high prevalence of asymmetry depending on the audiological criterion, the results of the work are a reason for further research in the development of a unified method for verifying a clinically significant form of ASNHL.

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