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Frontiers in Psychology 2023Congenital toxoplasmosis (CT) occurs mainly by primary maternal infection during pregnancy. It is estimated that the incidence of vertical transmission to the fetus is...
BACKGROUND
Congenital toxoplasmosis (CT) occurs mainly by primary maternal infection during pregnancy. It is estimated that the incidence of vertical transmission to the fetus is 20% and that infected women are more likely to have a premature birth or low birth weight neonate since there is an association between CT and the rate of premature birth and low birth weight. In addition to severe neurological and ophthalmic consequences, hearing disorders such as hearing loss are also among the clinical manifestations seen in children with CT. Given the above, the objective of this study is to verify what are the auditory disorders seen in children with CT.
METHODS
This literature review was structured according to the PRISMA statement and based on the terms of Study Target Population, Intervention, Comparison, Outcomes, and Study Types (PICOS). To obtain the studies, the following electronic databases were consulted: PubMed, Web of Science, Scopus, and Lilacs. The combined terms used for the search were: ("auditory evoked potentials" OR "hearing" OR "hearing loss") AND ("congenital toxoplasmosis"). The selection of articles was carried out independently, blindly, by two of the authors, to minimize risk of bias.
RESULTS
The search in the databases identified 172 articles, after excluding duplicate articles, 105 studies were identified. From the selection made by reading the titles and abstracts, 11 studies were selected for full-text reading. A total of 94 studies were excluded. An article was selected from the list of references. Therefore, 12 studies were included in the final analysis. It was observed that a significant percentage of studies sought to study the peripheral auditory pathway, verifying the occurrence or association between hearing loss and the presence of congenital infection. Only two studies evaluated the central auditory pathway, using the Brainstem Auditory Evoked Potential (BAEP) and the Frequency Following Response (FFR).
CONCLUSION
Toxoplasmosis affects not only the peripheral areas but central areas as well. Most studies suggest this pathology as a risk factor for both peripheral and central impairment. Research has found a greater association between CT and mild to moderate hearing loss, in addition to alterations in exams such as BAEP and FFR. These data recommend that CT be reported as a global public health problem and can help assess complications and impacts of hearing disorders as a result of CT. There is a gap about studies that retract the co-occurrence between CT and other Risk Indicators for Hearing Loss (RIHL), such as prematurity, permanence in the intensive care unit, and use of ototoxic medications, lack of longitudinal studies, that accompany the development of hearing and language of children with CT, since the consequences of this infection may be late.
PubMed: 38298366
DOI: 10.3389/fpsyg.2023.1286211 -
Preventive Medicine Mar 2024This systematic review explores the multifaceted nature of risk factors contributing to adult-onset HL. The objective was to synthesise the most recent epidemiological... (Meta-Analysis)
Meta-Analysis Review
BACKGROUND
This systematic review explores the multifaceted nature of risk factors contributing to adult-onset HL. The objective was to synthesise the most recent epidemiological evidence to generate pooled proportional incidences for the identified risk factors.
METHODS
We conducted an extensive search of electronic databases (MEDLINE, EMBASE, and psychINFO) for studies providing epidemiological evidence of risk factors associated with hearing loss. Topic modelling using Latent Dirichlet Allocation (LDA) was first conducted to determine how many risk factor themes were available from the papers. Data were analysed by calculating the pooled proportional incidence using a meta-analysis of proportions.
RESULTS
From the 72 studies reviewed, six key risk factor themes emerged through LDA topic modelling. The review identified ototoxicity, primarily caused by cancer treatments and antibiotics, infectious diseases like COVID-19, occupational noise exposure, lifestyle factors, health conditions, biological responses, and age progression as significant risk factors for HL. The highest proportional incidence was found with cancer-related ototoxicity at 55.4% (95%CI: 39.0-70.7), followed closely by ototoxicity from infectious diseases at 50.0% (95%CI: 28.5-71.5). This high proportional incidence suggests the need to explore less destructive therapies and proactively monitor hearing function during treatments.
CONCLUSIONS
The findings of this review, combined with the synthesis of epidemiological evidence, enhance our understanding of hearing loss (HL) pathogenesis and highlight potential areas for intervention, thereby paving the way for more effective prevention and management of adult-onset hearing loss in our ageing global population.
Topics: Adult; Humans; Ototoxicity; Hearing Loss; Risk Factors; Anti-Bacterial Agents; Communicable Diseases
PubMed: 38296002
DOI: 10.1016/j.ypmed.2024.107882 -
Frontiers in Pharmacology 2024This study evaluated the potential of high-molecular-weight hyaluronic acid (HHA) as an intratympanic (IT) drug delivery vehicle for dexamethasone (D) in treating acute...
This study evaluated the potential of high-molecular-weight hyaluronic acid (HHA) as an intratympanic (IT) drug delivery vehicle for dexamethasone (D) in treating acute hearing loss. We compared the efficacy, safety, and residence time of HHA to the standard-of-care IT drug delivery method. Endoscopic examinations were used to track tympanic membrane (TM) healing post-IT injection. Micro-computed tomography (CT) was used to gauge drug/vehicle persistence in the bulla air space. Histological analyses covered the middle ear, TM, and hair cell counts. Auditory brainstem responses (ABR) were used to measure hearing thresholds, while high-performance liquid chromatography (HPLC) was employed to quantify cochlear perilymph dexamethasone concentrations. The HHA + D group had a notably prolonged drug/vehicle residence time in the bulla (41 ± 27 days) compared to the saline + D group (1.1 ± 0.3 days). Complete TM healing occurred without adverse effects. Histology revealed no significant intergroup differences or adverse outcomes. Hearing recovery trends favored the HHA + D group, with 85.0% of ears showing clinically meaningful improvement. D concentrations in cochlear perilymph were roughly double in the HHA group. HHA is a promising vehicle for IT drug delivery in treating acute hearing loss. It ensures extended residence time, augmented drug concentrations in targeted tissues, and safety. These results highlight the potential for HHA + D to excel beyond existing standard-of-care treatments for acute hearing loss.
PubMed: 38292943
DOI: 10.3389/fphar.2024.1294657 -
Frontiers in Neuroscience 2023Hearing loss is the most common sensory disorder in human beings. Cochlear sensory cells are the basis of hearing. Cochlear sensory cells suffer from various acute or... (Review)
Review
Hearing loss is the most common sensory disorder in human beings. Cochlear sensory cells are the basis of hearing. Cochlear sensory cells suffer from various acute or chronic injuries, such as excessive sound stimulation, ototoxic drugs, and age-related degeneration. In response to these stresses, the cochlea develops an immune response. In recent years, studies have shown that the immune response of the inner ear has been regarded as one of the important pathological mechanisms of inner ear injury. Therapeutic interventions for inflammatory responses can effectively alleviate different types of inner ear injury. As the main immune cells in the inner ear, macrophages are involved in the process of inner ear injury caused by various exogenous factors. However, its specific role in the immune response of the inner ear is still unclear. This review focuses on discusses the dynamic changes of macrophages during different types of inner ear injury, and clarifies the potential role of macrophage-related immune response in inner ear injury.
PubMed: 38274500
DOI: 10.3389/fnins.2023.1339134 -
Clinical and Experimental... Feb 2024Cochlear hair cells convert sound into electrical signals that are relayed via the spiral ganglion neurons to the central auditory pathway. Hair cells are vulnerable to... (Review)
Review
Cochlear hair cells convert sound into electrical signals that are relayed via the spiral ganglion neurons to the central auditory pathway. Hair cells are vulnerable to damage caused by excessive noise, aging, and ototoxic agents. Non-mammals can regenerate lost hair cells by mitotic regeneration and direct transdifferentiation of surrounding supporting cells. However, in mature mammals, damaged hair cells are not replaced, resulting in permanent hearing loss. Recent studies have uncovered mechanisms by which sensory organs in non-mammals and the neonatal mammalian cochlea regenerate hair cells, and outlined possible mechanisms why this ability declines rapidly with age in mammals. Here, we review similarities and differences between avian, zebrafish, and mammalian hair cell regeneration. Moreover, we discuss advances and limitations of hair cell regeneration in the mature cochlea and their potential applications to human hearing loss.
PubMed: 38271988
DOI: 10.21053/ceo.2023.01382 -
Frontiers in Cell and Developmental... 2023Aminoglycosides are commonly used for the treatment of life-threatening bacterial infections, however, aminoglycosides may cause irreversible hearing loss with a... (Review)
Review
Aminoglycosides are commonly used for the treatment of life-threatening bacterial infections, however, aminoglycosides may cause irreversible hearing loss with a long-term clinical therapy. The mechanism and prevention of the ototoxicity of aminoglycosides are still limited although amounts of studies explored widely. Specifically, advancements in programmed cell death (PCD) provide more new perspectives. This review summarizes the general signal pathways in programmed cell death, including apoptosis, autophagy, and ferroptosis, as well as the mechanisms of aminoglycoside-induced ototoxicity. Additionally, novel interventions, especially gene therapy strategies, are also investigated for the prevention or treatment of aminoglycoside-induced hearing loss with prospective clinical applications.
PubMed: 38259515
DOI: 10.3389/fcell.2023.1305433 -
International Journal of Molecular... Jan 2024Our study investigated the embryo-ototoxic effects of deodorant2 (DA2) on zebrafish embryos, which serve as valuable model organisms due to genetic and physiological...
Our study investigated the embryo-ototoxic effects of deodorant2 (DA2) on zebrafish embryos, which serve as valuable model organisms due to genetic and physiological similarities to humans. We focused on understanding DA2's impact on zebrafish hair cells, which are vital for sensory perception and balance regulation. DA2, provided by the Ministry of Environment, Republic of Korea, was used at 460 μg/mL in dimethyl sulfoxide (DMSO), with a 0.43% DMSO solvent control group. Three experiments, each using 10 zebrafish specimens from each group, showed an initial 13% hair cell count reduction in the DA2-exposed group. Subsequent experiments demonstrated reductions of 37% and 22%, each with one mortality case. Statistical analysis revealed a significant 24% hair cell count reduction in the DA2-exposed group. We also assessed DA2's impact on zebrafish behavior. Although not statistically significant, differences in distances traveled (0.33-0.39, 95% confidence interval: -0.46-1.1, = 0.2033) and latencies (-0.016-0.018, 95% confidence interval: -0.052-0.021, = 0.1917) hinted at negative effects. These results highlight DA2's ototoxic properties affecting zebrafish auditory systems and behavior. Further investigation into DA2's effects on aquatic organisms and potential mitigation strategies are essential. These findings contribute to understanding DA2's safety profile, benefiting aquatic ecosystems and human health assessments.
Topics: Humans; Animals; Deodorants; Dimethyl Sulfoxide; Ecosystem; Zebrafish; Embryo, Mammalian; Ototoxicity; Perciformes
PubMed: 38256022
DOI: 10.3390/ijms25020948 -
Biomolecules Jan 2024Recent advances in cochlear implantology are exemplified by novel functional strategies such as bimodal electroacoustic stimulation, in which the patient has intact...
Recent advances in cochlear implantology are exemplified by novel functional strategies such as bimodal electroacoustic stimulation, in which the patient has intact low-frequency hearing and profound high-frequency hearing pre-operatively. Therefore, the synergistic restoration of dysfunctional cochlear hair cells and the protection of hair cells from ototoxic insults have become a persistent target pursued for this hybrid system. In this study, we developed a composite GelMA/PEDOT:PSS conductive hydrogel that is suitable as a coating for the cochlear implant electrode for the potential local delivery of otoregenerative and otoprotective drugs. Various material characterization methods (e.g., H NMR spectroscopy, FT-IR, EIS, and SEM), experimental models (e.g., murine cochlear organoid and aminoglycoside-induced ototoxic HEI-OC1 cellular model), and biological analyses (e.g., confocal laser scanning microscopy, real time qPCR, flow cytometry, and bioinformatic sequencing) were used. The results demonstrated decent material properties of the hydrogel, such as mechanical (e.g., high tensile stress and Young's modulus), electrochemical (e.g., low impedance and high conductivity), biocompatibility (e.g., satisfactory cochlear cell interaction and free of systemic toxicity), and biosafety (e.g., minimal hemolysis and cell death) features. In addition, the CDR medicinal cocktail sustainably released by the hydrogel not only promoted the expansion of the cochlear stem cells but also boosted the trans-differentiation from cochlear supporting cells into hair cells. Furthermore, hydrogel-based drug delivery protected the hair cells from oxidative stress and various forms of programmed cell death (e.g., apoptosis and ferroptosis). Finally, using large-scale sequencing, we enriched a complex network of signaling pathways that are potentially downstream to various metabolic processes and abundant metabolites. In conclusion, we present a conductive hydrogel-based local delivery of bifunctional drug cocktails, thereby serving as a potential solution to intracochlear therapy of bimodal auditory rehabilitation and diseases beyond.
Topics: Humans; Animals; Mice; Hydrogels; Spectroscopy, Fourier Transform Infrared; Hair Cells, Auditory; Cell Communication; Signal Transduction
PubMed: 38254695
DOI: 10.3390/biom14010095 -
The Lancet. Global Health Feb 2024Hearing loss affects approximately 1·6 billion individuals worldwide. Many cases are preventable. We aimed to estimate the annual number of new hearing loss cases that...
BACKGROUND
Hearing loss affects approximately 1·6 billion individuals worldwide. Many cases are preventable. We aimed to estimate the annual number of new hearing loss cases that could be attributed to meningitis, otitis media, congenital rubella syndrome, cytomegalovirus, and ototoxic medications, specifically aminoglycosides, platinum-based chemotherapeutics, and antimalarials.
METHODS
We used a targeted and a rapid systematic literature review to calculate yearly global incidences of each cause of hearing loss. We estimated the prevalence of hearing loss for each presumed cause. For each cause, we calculated the global number of yearly hearing loss cases associated with the exposure by multiplying the estimated exposed population by the prevalence of hearing loss associated with the exposure, accounting for mortality when warranted.
FINDINGS
An estimated 257·3 million people per year are exposed to these preventable causes of hearing loss, leading to an estimated 33·8 million new cases of hearing loss worldwide per year. Most hearing loss cases were among those with exposure to ototoxic medications (19·6 million [range 12·6 million-27·9 million] from short-course aminoglycoside therapy and 12·3 million from antimalarials). We estimated that 818 000 cases of hearing loss were caused by otitis media, 346 000 by meningitis, 114 000 by cytomegalovirus, and 59 000 by congenital rubella syndrome.
INTERPRETATION
The global burden of preventable hearing loss is large. Hearing loss that is attributable to disease sequelae or ototoxic medications contributes substantially to the global burden of hearing loss. Prevention of these conditions should be a global health priority.
FUNDING
The US National Institute on Deafness and Other Communication Disorders and the US National Institute on Aging.
Topics: Humans; Rubella Syndrome, Congenital; Antimalarials; Hearing Loss; Meningitis; Otitis Media
PubMed: 38245112
DOI: 10.1016/S2214-109X(23)00514-4 -
Frontiers in Cellular Neuroscience 2023Cholesterol is the most abundant sterol molecule in mammalian cells, which not only constitutes the cell membrane but also plays essential roles in the synthesis of... (Review)
Review
Cholesterol is the most abundant sterol molecule in mammalian cells, which not only constitutes the cell membrane but also plays essential roles in the synthesis of important hormones, synapse formation, and cell signal transduction. The effect of hypercholesterolemia on hearing has been studied extensively, and multiple studies have demonstrated that hypercholesterolemia is a risk factor for hearing loss. However, the impact of cholesterol homeostasis within auditory cells on peripheral auditory development and maintenance has not been evaluated in detail. Mutations in certain cholesterol metabolism-related genes, such as , , , and , as well as derivatives of cholesterol metabolism-related ototoxic drugs, such as β-cyclodextrin, can lead to disruptions of cholesterol homeostasis within auditory cells, resulting in hearing loss. This article aims to review the impact of cholesterol homeostasis within auditory cells on the peripheral auditory function from the following two perspectives: (1) changes in cholesterol homeostasis regulatory genes in various hearing loss models; (2) mechanisms underlying the effects of some drugs that have a therapeutic effect on hearing loss via regulating cholesterol homeostasis. This article aims to summarize and analyze the impact of disruption of cellular cholesterol homeostasis within auditory cells on hearing, in order to provide evidence regarding the underlying mechanisms.
PubMed: 38239289
DOI: 10.3389/fncel.2023.1308028