Background: The Fischer 344/NHsd rat undergoes age-related, progressive, high-frequency hearing loss beginning at age 12 months. The loss has been linked to defects/death in the outer hair cells related to oxidative stress originating in the mitochondria. Acetyl L-carnitine (ALCAR) is known to enhance mitochondrial bioenergetics and membrane efficiency. Therefore, ALCAR was targeted as a possible pharmacologic intervention to prevent, or even restore, hearing loss from aging.
Methods: Three different paradigms were used to deliver ALCAR to aging Fischer 344/NHsd rats. Rats in each condition had their hearing evaluated by auditory brainstem responses before, during, and after treatment. First, 24-month-old rats were given ALCAR (100 mg/kg dissolved 25 mg/ml in saline) by IP injection daily for one month. Second, 18-month-old rats were given ALCAR (100 mg/kg) by oral gavage for 90 days. Third, 15-month-old rats were given ALCAR (100 mg/kg) by oral gavage for 90 days. Control rats in each condition received saline by i.p. injection or gavage.
Results: Hearing thresholds of the three sets of ALCAR-treated animals were never significantly different from their matched controls before, during, or after the treatments at any of the five test stimuli (5, 10, 20, and 40 kHz tone bursts and a click).
Conclusion: The current study does not provide evidence that age-related hearing loss in the Fischer 344/NHsd rat can be altered with systemic administration of ALCAR.
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http://dx.doi.org/10.1186/1477-5751-7-4 | DOI Listing |
Biochem Genet
January 2025
Department of Dermatology, Yale University School of Medicine, New Haven, CT, USA.
Non-syndromic hearing loss (NSHL) is a genetically heterogeneous disorder accounting for almost 70% of the total congenital hearing loss. The implementation of rapid advanced sequencing methods has significantly contributed to the correct molecular diagnosis for several rare genetic disorders, including NHSL. Features of two probands with NHSL were clinically and genetically evaluated.
View Article and Find Full Text PDFJ Vis Exp
December 2024
Department of Otolaryngology, Head and Neck Surgery, Beijing Children's Hospital, Capital Medical University, National Center for Children's Health;
Single-sided deafness (SSD), where there is severe to profound hearing loss in one ear and normal hearing in the other, is a prevalent auditory condition that significantly impacts the quality of life for those affected. The ability to accurately localize sound sources is crucial for various everyday activities, including speech communication and environmental awareness. In recent years, bone conduction intervention has emerged as a promising solution for patients with SSD, offering a non-invasive alternative to traditional air conduction hearing aids.
View Article and Find Full Text PDFAge-related hearing loss (ARHL) is considered one of the most common neurodegenerative disorders in the elderly; however, how it contributes to cognitive decline is poorly understood. With resting-state functional magnetic resonance imaging from 66 individuals with ARHL and 54 healthy controls, group spatial independent component analyses, sliding window analyses, graph-theory methods, multilayer networks, and correlation analyses were used to identify ARHL-induced disturbances in static and dynamic functional network connectivity (sFNC/dFNC), alterations in global network switching and their links to cognitive performances. ARHL was associated with decreased sFNC/dFNC within the default mode network (DMN) and increased sFNC/dFNC between the DMN and central executive, salience (SN), and visual networks.
View Article and Find Full Text PDFFront Aging Neurosci
December 2024
Department of Psychology, Game Design, and Physical Therapy, Movement and Rehabilitation Services, Northeastern University, Boston, MA, United States.
A growing literature suggests that declines in sensory/perceptual systems predate cognitive declines in aging, and furthermore, they are highly predictive for developing Alzheimer's disease and Alzheimer's related dementias (ADRD). While vision, hearing, olfaction, and vestibular function have each been shown to be related to ADRD, their causal relations to cognitive declines, how they interact with each other remains to be clarified. Currently, there is substantial debate whether sensory/perceptual systems that fail early in disease progression are causal in their contributions to cognitive load and/or social isolation or are simply coincident declines due to aging.
View Article and Find Full Text PDFIran J Public Health
December 2024
Department of Social Medicine, Faculty of Medical Sciences, University of Kragujevac, Kragujevac, Serbia.
Background: Sensory impairments, notably hearing loss (68% in those aged 70+) and vision loss (24%-50%), are prevalent in older individuals. We investigated the correlation between visual and hearing impairments in older adults, considering sociodemographic factors, mental health, and social support.
Methods: The study is part of The Serbian 2019 National Health Survey, conducted in 2019.
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