Degeneration of stria vascularis in age-related hearing loss; a corrosion cast study in a mouse model

2016 ◽  
Vol 136 (4) ◽  
pp. 385-390 ◽  
Author(s):  
Mattia Carraro ◽  
Robert V. Harrison
Pharmaceutics ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 1041
Author(s):  
Jacqueline Chester ◽  
Edan Johnston ◽  
Daniel Walker ◽  
Melissa Jones ◽  
Corina Mihaela Ionescu ◽  
...  

Aging is considered a contributing factor to many diseases such as cardiovascular disease, Alzheimer’s disease, and hearing loss. Age-related hearing loss, also termed presbycusis, is one of the most common sensory impairments worldwide, affecting one in five people over 50 years of age, and this prevalence is growing annually. Associations have emerged between presbycusis and detrimental health outcomes, including social isolation and mental health. It remains largely untreatable apart from hearing aids, and with no globally established prevention strategies in the clinical setting. Hence, this review aims to explore the pathophysiology of presbycusis and potential therapies, based on a recent advancement in bile acid-based bio-nanotechnologies. A comprehensive online search was carried out using the following keywords: presbycusis, drugs, hearing loss, bile acids, nanotechnology, and more than 150 publications were considered directly relevant. Evidence of the multifaceted oxidative stress and chronic inflammation involvement in cellular damage and apoptosis that is associated with a loss of hair cells, damaged and inflamed stria vascularis, and neuronal signalling loss and apoptosis continues to emerge. New robust and effective therapies require drug delivery deeper into the various layers of the cochlea. Bile acid-based nanotechnology has gained wide interest in its permeation-enhancing ability and potential for numerous applications in treating presbycusis.


2013 ◽  
Vol 22 (2) ◽  
pp. 299-302 ◽  
Author(s):  
Robert D. Frisina ◽  
D. Robert Frisina

Purpose The aim of this study was to highlight growing evidence of interactions between hormones and the structure and function of the auditory system. Method Recent studies implicating sex hormones and other natural hormones in the modulation of hearing status in age-related hearing loss were reviewed. Results Progesterone, a sex hormone, has been shown to have negative effects on the hearing of older women and aging mice, whereas, in contrast, estrogen was found in some cases to have a positive influence. Aldosterone, used in studies of animal models of autoimmune hearing loss, slowed the progression of hearing loss. Follow-up studies in humans revealed that auditory measures varied as serum aldosterone levels shifted within the normal range, in otherwise healthy older subjects. This was true for simple as well as complex auditory tasks (i.e., sound spatial processing), suggesting benefits of aldosterone to postperipheral auditory processing as well. In addition, evidence suggests that this functional hearing improvement occurred in association with anatomical improvements to the stria vascularis—an important site of anatomical change in presbycusis. Conclusions Audiology is now at the point where the search for biomedical interventions to modulate or prevent age-related hearing loss can move forward. Such interventions would require multidisciplinary collaborative initiatives by researchers in such areas as drug development, anatomy, auditory physiological and perceptual testing, and drug microdelivery systems.


Antioxidants ◽  
2021 ◽  
Vol 10 (9) ◽  
pp. 1497
Author(s):  
Luz del Mar Rivas-Chacón ◽  
Sofía Martínez-Rodríguez ◽  
Raquel Madrid-García ◽  
Joaquín Yanes-Díaz ◽  
Juan Ignacio Riestra-Ayora ◽  
...  

Age-related hearing loss (ARHL) is an increasing and gradual sensorineural hearing dysfunction. Oxidative stress is an essential factor in developing ARHL; additionally, premature senescence of auditory cells induced by oxidative stress can produce hearing loss. Hydrogen peroxide (H2O2) represents a method commonly used to generate cellular senescence in vitro. The objective of the present paper is to study H2O2-induced senescence patterns in three auditory cell lines (House Ear Institute-Organ of Corti 1, HEI-OC1; organ of Corti, OC-k3, and stria vascularis, SV-k1 cells) to elucidate the intrinsic mechanisms responsible for ARHL. The auditory cells were exposed to H2O2 at different concentrations and times. The results obtained show different responses of the hearing cells concerning cell growth, β-galactosidase activity, morphological changes, mitochondrial activation, levels of oxidative stress, and other markers of cell damage (Forkhead box O3a, FoxO3a, and 8-oxoguanine, 8-oxoG). Comparison between the responses of these auditory cells to H2O2 is a helpful method to evaluate the molecular mechanisms responsible for these auditory cells’ senescence. Furthermore, this in vitro model could help develop anti-senescent therapeutic strategies for the treatment of AHRL.


2018 ◽  
Vol 9 (4) ◽  
pp. 664 ◽  
Author(s):  
Aurore Marie ◽  
Johann Meunier ◽  
Emilie Brun ◽  
Susanna Malmstrom ◽  
Veronique Baudoux ◽  
...  

2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
Chisato Fujimoto ◽  
Tatsuya Yamasoba

Age-related hearing loss (ARHL), the progressive loss of hearing associated with aging, is the most common sensory disorder in the elderly population. The pathology of ARHL includes the hair cells of the organ of Corti, stria vascularis, and afferent spiral ganglion neurons as well as the central auditory pathways. Many studies have suggested that the accumulation of mitochondrial DNA damage, the production of reactive oxygen species, and decreased antioxidant function are associated with subsequent cochlear senescence in response to aging stress. Mitochondria play a crucial role in the induction of intrinsic apoptosis in cochlear cells. ARHL can be prevented in laboratory animals by certain interventions, such as caloric restriction and supplementation with antioxidants. In this review, we will focus on previous research concerning the role of the oxidative stress and mitochondrial dysfunction in the pathology of ARHL in both animal models and humans and introduce concepts that have recently emerged regarding the mechanisms of the development of ARHL.


Author(s):  
Giulia Gentile ◽  
Fabiola Paciello ◽  
Veronica Zorzi ◽  
Antonio Gianmaria Spampinato ◽  
Maria Guarnaccia ◽  
...  

Pathogenic mutations in the non-syndromic hearing loss and deafness 1 (DFNB1) locus are the primary cause of monogenic inheritance for prelingual hearing loss. To unravel molecular pathways involved in etiopathology and look for early degeneration biomarkers, we used a system biology approach to analyze Cx30−/− mice at an early cochlear post-natal developmental stage. These mice are a DFNB1 mouse model with severely reduced expression levels of two connexins in the inner ear, Cx30, and Cx26. Integrated analysis of miRNA and mRNA expression profiles in the cochleae of Cx30−/− mice at post-natal day 5 revealed the overexpression of five miRNAs (miR-34c, miR-29b, miR-29c, miR-141, and miR-181a) linked to apoptosis, oxidative stress, and cochlear degeneration, which have Sirt1 as a common target of transcriptional and/or post-transcriptional regulation. In young adult Cx30−/− mice (3 months of age), these alterations culminated with blood barrier disruption in the Stria vascularis (SV), which is known to have the highest aerobic metabolic rate of all cochlear structures and whose microvascular alterations contribute to age-related degeneration and progressive decline of auditory function. Our experimental validation of selected targets links hearing acquisition failure in Cx30−/− mice, early oxidative stress, and metabolic dysregulation to the activation of the Sirt1–p53 axis. This is the first integrated analysis of miRNA and mRNA in the cochlea of the Cx30−/− mouse model, providing evidence that connexin downregulation determines a miRNA-mediated response which leads to chronic exhaustion of cochlear antioxidant defense mechanisms and consequent SV dysfunction. Our analyses support the notion that connexin dysfunction intervenes early on during development, causing vascular damage later on in life. This study identifies also early miRNA-mediated biomarkers of hearing impairment, either inherited or age related.


2014 ◽  
Vol 51 ◽  
pp. 8-14 ◽  
Author(s):  
Hao Xiong ◽  
Min Dai ◽  
Yongkang Ou ◽  
Jiaqi Pang ◽  
Haidi Yang ◽  
...  

2013 ◽  
Vol 2013 ◽  
pp. 1-12 ◽  
Author(s):  
Makoto Kinoshita ◽  
Takashi Sakamoto ◽  
Akinori Kashio ◽  
Takahiko Shimizu ◽  
Tatsuya Yamasoba

Age-related hearing loss (AHL) reduces the quality of life for many elderly individuals. Manganese superoxide dismutase (Mn-SOD), one of the antioxidant enzymes acting within the mitochondria, plays a crucial role in scavenging reactive oxygen species (ROS). To determine whether reduction in Mn-SOD accelerates AHL, we evaluated auditory function in Mn-SOD heterozygous knockout (HET) mice and their littermate wild-type (WT) C57BL/6 mice by means of auditory brainstem response (ABR). Mean ABR thresholds were significantly increased at 16 months when compared to those at 4 months in both WT and HET mice, but they did not significantly differ between them at either age. The extent of hair cell loss, spiral ganglion cell density, and thickness of the stria vascularis also did not differ between WT and HET mice at either age. At 16 months, immunoreactivity of 8-hydroxydeoxyguanosine was significantly greater in the SGC and SV in HET mice compared to WT mice, but that of 4-hydroxynonenal did not differ between them. These findings suggest that, although decrease of Mn-SOD by half may increase oxidative stress in the cochlea to some extent, it may not be sufficient to accelerate age-related cochlear damage under physiological aging process.


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