Animal studies demonstrate that noise exposure can permanently damage the synapses between inner hair cells and auditory nerve fibers, even when outer hair cells are intact and there is no clinically relevant permanent threshold shift. Synaptopathy disrupts the afferent connection between the cochlea and the central auditory system and is predicted to impair speech understanding in noisy environments and potentially result in tinnitus and/or hyperacusis. While cochlear synaptopathy has been demonstrated in numerous experimental animal models, synaptopathy can only be confirmed through post-mortem temporal bone analysis, making it difficult to study in living humans. A variety of non-invasive measures have been used to determine whether noise-induced synaptopathy occurs in humans, but the results are conflicting. The overall objective of this article is to synthesize the existing data on the functional impact of noise-induced synaptopathy in the human auditory system. The first section of the article summarizes the studies that provide evidence for and against noise-induced synaptopathy in humans. The second section offers potential explanations for the differing results between studies. The final section outlines suggested methodologies for diagnosing synaptopathy in humans with the aim of improving consistency across studies.
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http://dx.doi.org/10.1016/j.heares.2019.02.016 | DOI Listing |
Front Biosci (Landmark Ed)
January 2025
Department of Neurology, Jinshan Hospital, Fudan University, 201508 Shanghai, China.
Background: Neuronal cholesterol deficiency may contribute to the synaptopathy observed in Alzheimer's disease (AD). However, the underlying mechanisms remain poorly understood. Intact synaptic vesicle (SV) mobility is crucial for normal synaptic function, whereas disrupted SV mobility can trigger the synaptopathy associated with AD.
View Article and Find Full Text PDFBiomolecules
January 2025
Institute of Neuroscience, Lobachevsky State University of Nizhny Novgorod, 23 Gagarin Ave., 603022 Nizhny Novgorod, Russia.
Developmental and epileptic encephalopathies (DEEs) are a group of neuropediatric diseases associated with epileptic seizures, severe delay or regression of psychomotor development, and cognitive and behavioral deficits. What sets DEEs apart is their complex interplay of epilepsy and developmental delay, often driven by genetic factors. These two aspects influence one another but can develop independently, creating diagnostic and therapeutic challenges.
View Article and Find Full Text PDFFunct Integr Genomics
January 2025
National Agri-Food and Biomanufacturing Institute, Sector-81, SAS Nagar, Knowledge City, Punjab, India.
Mitochondria, the cellular powerhouses, are pivotal to neuronal function and health, particularly through their role in regulating synaptic structure and function. Spine reprogramming, which underlies synapse development, depends heavily on mitochondrial dynamics-such as biogenesis, fission, fusion, and mitophagy as well as functions including ATP production, calcium (Ca) regulation, and retrograde signaling. Mitochondria supply the energy necessary for assisting synapse development and plasticity, while also regulating intracellular Ca homeostasis to prevent excitotoxicity and support synaptic neurotransmission.
View Article and Find Full Text PDFJAMA Netw Open
January 2025
Alzheimer Center Limburg, Department of Psychiatry and Neuropsychology, School for Mental Health and Neuroscience, Maastricht University, Maastricht, the Netherlands.
Importance: Baseline cerebral microbleeds (CMBs) and APOE ε4 allele copy number are important risk factors for amyloid-related imaging abnormalities in patients with Alzheimer disease (AD) receiving therapies to lower amyloid-β plaque levels.
Objective: To provide prevalence estimates of any, no more than 4, or fewer than 2 CMBs in association with amyloid status, APOE ε4 copy number, and age.
Design, Setting, And Participants: This cross-sectional study used data included in the Amyloid Biomarker Study data pooling initiative (January 1, 2012, to the present [data collection is ongoing]).
Acta Neuropathol
January 2025
Department of Neurology, NYU Grossman School of Medicine, New York, NY, USA.
Down syndrome (DS) is strongly associated with Alzheimer's disease (AD) due to APP overexpression, exhibiting Amyloid-β (Aβ) and Tau pathology similar to early-onset (EOAD) and late-onset AD (LOAD). We evaluated the Aβ plaque proteome of DS, EOAD, and LOAD using unbiased localized proteomics on post-mortem paraffin-embedded tissues from four cohorts (n = 20/group): DS (59.8 ± 4.
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