Search

Redox imbalance and inflammation have been proposed as the principal mechanisms of damage in the auditory system, resulting in functional alterations and hearing loss. Microglia and astrocytes play a crucial role in mediating oxidative/inflammatory injury in the central nervous system; however, the role of glial cells in the auditory damage is still elusive. In this study, we investigated glial-mediated responses to toxic injury in peripheral and central structures of the auditory pathway, i.e., the cochlea and the auditory cortex (ACx), in rats exposed to styrene, a volatile compound with well-known oto/neurotoxic properties. To this aim, male adult Wistar rats were treated with styrene (400 mg/kg daily for 3 weeks, 5/ days a week). At the end of treatment (day 21) electrophysiological, morphological, immunofluorescence and molecular analyses were performed in both the cochlea and in ACx samples to evaluate the mechanisms underlying styrene-in-duced oto/neurotoxicity in the auditory system. We showed that the oto/neurotoxic insult induced by styrene increases oxidative stress in both cochlea and ACx. This was associated with macrophages and glial cell activation, increased expression of inflammatory markers (i.e., pro-inflammatory cytokines and chemokine receptors) and alterations in con-nexin (Cxs) and pannexin (Panx) expression, likely responsible for dysregulation of the microglia/astrocyte network. Specifically, we found downregulation of Cx26 and Cx30 in the cochlea, and high level of Cx43 and Panx1 in the ACx. Collectively, our results provide novel evidence on the role of immune and glial cell activation in the oxidative/inflammatory damage induced by styrene in the auditory system at both peripheral and central levels, also involving alterations of gap junction networks. Our data suggest that targeting glial cells and connexin/pannexin expression might be useful to attenuate oxidative/inflammatory damage in the auditory system. [ABSTRACT FROM AUTHOR]

Cisplatin-induced sensorineural hearing loss is a significant clinical challenge and, currently, only one drug has been approved by Food and Drug Administration as an effective treatment. Thus, several efforts are needed to better understand cisplatin mechanism of damage and to explore new therapeutic strategies. Although the potential effects of brain-derived neurotrophic factor (BDNF) have previously been investigated in some ototoxicity models, its efficacy in cisplatin-induced hearing loss remains uncertain. This study aimed to investigate the therapeutic potential of recombinant human BDNF (rhBDNF) local delivery in counteracting cochlear damage in an in in vivo model of cisplatin-induced ototoxicity. Thus, adult Wistar rats were treated with cisplatin (12 mg/kg, in-traperitoneally injected) and after one hour, they received 5 mg/kg of rhBDNF suspended in a thermogel by a transtympanic injection. Auditory brainstem responses were recorded to evaluate hearing function at 1, 3 and 7 days after treatment. Seven days after cisplatin treatment, we collected cochlear samples to perform, morphological, immunofluorescence, and molecular analyses to investigate the molecular mechanisms underlying the beneficial effects of our rhBDNF formulation. Our data showed that rhBDNF mitigates hearing loss in cisplatin-exposed rats by preserving synaptic connections in the cochlear epithelium and reducing hair cell and spiral ganglion neuron death. rhBDNF maintains the balance of its receptor levels (pTrkB and p75), boosting TrkB-CREB pro-survival signalling and reducing caspase 3-dependent apoptosis in the cochlea. Additionally, it activates antioxidant mechanisms while inhibiting inflammation and promoting vascular repair. Overall, our study demonstrates that the early transtympanic treatment with rhBDNF plays a multi-faceted protective role against cisplatin-induced ototoxicity, thus holding promise as a novel potential approach to preserve hearing in adult and pediatric patients undergoing cisplatin-based chemotherapy. [ABSTRACT FROM AUTHOR]

Background and Purpose: Cisplatin-induced sensorineural hearing loss is a significant clinical challenge. Although the potential effects of brain-derived neurotrophic factor (BDNF) have previously been investigated in some ototoxicity models, its efficacy in cisplatin-induced hearing loss remains uncertain. This study aimed to investigate the therapeutic potential of recombinant human BDNF (rhBDNF) in protecting cells against cisplatin-induced ototoxicity., Experimental Approach: Using an in vivo model of cisplatin-induced hearing loss, we investigated the beneficial effects of transtympanic administration of rhBDNF in a thermogel solution on hearing function and cochlear injury, using electrophysiological, morphological, immunofluorescence and molecular analyses., Key Results: Our data showed that local rhBDNF treatment counteracted hearing loss in rats receiving cisplatin by preserving synaptic connections in the cochlear epithelium and protecting hair cells (HCs) and spiral ganglion neurons (SGNs) against cisplatin-induced cell death. Specifically, rhBDNF maintains the balance of its receptor levels (pTrkB and p75), boosting TrkB-CREB pro-survival signalling and reducing caspase 3-dependent apoptosis in the cochlea. Additionally, it activates antioxidant mechanisms while inhibiting inflammation and promoting vascular repair., Conclusion and Implications: Collectively, we demonstrated that early transtympanic treatment with rhBDNF plays a multifaceted protective role against cisplatin-induced ototoxicity, thus holding promise as a novel potential approach to preserve hearing in adult and paediatric patients undergoing cisplatin-based chemotherapy., (© 2024 The Author(s). British Journal of Pharmacology published by John Wiley & Sons Ltd on behalf of British Pharmacological Society.)

Introduction: Purpose of our study was to compare two competing methods of performing bisyllabic word speech audiometry for the detection of the 50% speech reception threshold in noise (SRT50)., Methods: Classic method is performed submitting multiple word lists at a fixed signal-to-noise ratio. A newer Fast method - Italian Fast Speech Reception Threshold 50 (IFastSRT50) - is performed by means of program software with a single list of bisyllabic words and noise intensity shifting., Results: Means comparison between SRT50 Classic and IFastSRT50 shows a slight significant correlation (r = 0.263; p = 0.044) and a wide significant difference: SRT50 Classic = -2.763 dB (SD = 4.1) and IFastSRT50 = -7.803 dB (SD = 2.1) (p < 0.0001). There is a high difference between the test execution time means (SRT50 Classic = 11 min, IFastSRT50 = 2 min; p < 0.0001). The correlation between test results and execution times was higher for SRT50 Classic than IFastSRT50., Conclusion: IFastSRT50 test is a reliable method to quickly investigate signal-to-noise ratio needed to obtain 50% of recognition scores with bisyllabic words; it allows less execution time than SRT50 Classic method and can avoid patient fatigue and other limitations of different speech discrimination tests in noise as sentences based ones., (© 2024 S. Karger AG, Basel.)

Background : Epistaxis, particularly in Hereditary Hemorrhagic Telangiectasia (HHT) patients, is a common otolaryngological emergency, often requiring complex management. A hierarchy of increasingly invasive interventions, from external compression of the nasal pyramid to nostril closure, is typically proposed and applied. Methods : We conducted a retrospective study on HHT patients to assess the effectiveness and longevity of invasive procedures postoperatively. Data were collected using the Epistaxis Severity Score (ESS) questionnaire. The primary focus was on changes in the frequency and intensity of epistaxis, while the secondary focus was on the overall quality of life. Results : This study found that invasive procedures initially improved the frequency and intensity of epistaxis in HHT patients. However, within 1 to 9 months postoperatively, these benefits often diminished, with hemorrhagic symptoms recurring at similar or worsened levels. Conclusions : The findings suggest a need for a cautious and restrained approach to using invasive treatments in managing epistaxis in HHT patients. Highly invasive procedures should be reserved for cases where less invasive methods fail, due to their temporary effectiveness and the risk of causing anatomical-functional changes in the rhino-sinus area, complicating future management of severe epistaxis.

Background: Redox imbalance and inflammation have been proposed as the principal mechanisms of damage in the auditory system, resulting in functional alterations and hearing loss. Microglia and astrocytes play a crucial role in mediating oxidative/inflammatory injury in the central nervous system; however, the role of glial cells in the auditory damage is still elusive., Objectives: Here we investigated glial-mediated responses to toxic injury in peripheral and central structures of the auditory pathway, i.e., the cochlea and the auditory cortex (ACx), in rats exposed to styrene, a volatile compound with well-known oto/neurotoxic properties., Methods: Male adult Wistar rats were treated with styrene (400 mg/kg daily for 3 weeks, 5/days a week). Electrophysiological, morphological, immunofluorescence and molecular analyses were performed in both the cochlea and the ACx to evaluate the mechanisms underlying styrene-induced oto/neurotoxicity in the auditory system., Results: We showed that the oto/neurotoxic insult induced by styrene increases oxidative stress in both cochlea and ACx. This was associated with macrophages and glial cell activation, increased expression of inflammatory markers (i.e., pro-inflammatory cytokines and chemokine receptors) and alterations in connexin (Cxs) and pannexin (Panx) expression, likely responsible for dysregulation of the microglia/astrocyte network. Specifically, we found downregulation of Cx26 and Cx30 in the cochlea, and high level of Cx43 and Panx1 in the ACx., Conclusions: Collectively, our results provide novel evidence on the role of immune and glial cell activation in the oxidative/inflammatory damage induced by styrene in the auditory system at both peripheral and central levels, also involving alterations of gap junction networks. Our data suggest that targeting glial cells and connexin/pannexin expression might be useful to attenuate oxidative/inflammatory damage in the auditory system., (© 2023. The Author(s).)

Objectives: Despite recent advances in biomolecular research that have improved our knowledge of cholesteatoma pathogenesis, the reasons behind its highly variable clinical course are still not clarified. It has been proposed that biological signaling between peri-matrix and matrix cells could play a critical role in disease homeostasis. The aim of our study was to analyze the expression of inflammatory (IL-1β), hyper-proliferative (STAT-3, TGF-β), and angiogenic (VEGF-C, PDGFr) factors in congenital and acquired cholesteatomas (both in adults and children), which might correlate with the clinical features observed. We performed an experimental study on 37 patients (29 males and 8 females, ranging from 4 to 66 years of age) who were diagnosed with cholesteatoma between 2020 and 2021 in our institution. All patients underwent clinical, audiologic, and radiologic assessments. Bone erosion grading and staging of cholesteatoma growth were assessed through preoperative evaluation and intraoperative middle ear findings, according to the PTAM System proposed by the Japan Otological Society (2016). Retro-auricular skin specimens were intraoperatively collected in all patients. Skin and cholesteatoma samples were analyzed through histopathological, western blot, and immunohistochemical evaluations. The expression rate was measured to find out the differences between congenital and acquired cholesteatomas as well as between the adult and pediatric populations. Expression of angiogenic, inflammatory, and proliferative biomarkers is significantly increased in acquired cholesteatomas in children as compared to congenital and acquired forms in adults, in accordance with the higher stage of disease shown by imaging, surgical, and histological features. Our data suggest that pathways already supposed to be involved in the pathogenesis of cholesteatomas could be differently activated in more destructive forms, typically found in children. The identification of potential biomarkers of cholesteatoma aggressiveness could lead to more personalized management (timing of intervention, recurrence prevention) and the future identification of anti-growth/anti-proliferative agents as non-surgery therapeutic options.

Cochlear redox unbalance is the main mechanism of damage involved in the pathogenesis of noise-induced-hearing loss. Indeed, the increased free radical production, in conjunction with a reduced efficacy of the endogenous antioxidant system, plays a key role in cochlear damage induced by noise exposure. For this reason, several studies focused on the possibility to use exogenous antioxidant to prevent or attenuate noise-induce injury. Thus, several antioxidant molecules, alone or in combination with other compounds, have been tested in both experimental and clinical settings. In our findings, we tested the protective effects of several antioxidant enzymes, spanning from organic compounds to natural compounds, such as nutraceuticals of polyphenols. In this review, we summarize and discuss the strengths and weaknesses of antioxidant supplementation focusing on polyphenols, Q-Ter, the soluble form of CoQ10, Vitamin E and N-acetil-cysteine, which showed great otoprotective effects in different animal models of noise induced hearing loss and which has been proposed in clinical trials.

Para-pharyngeal space (PPS) tumors include an heterogeneous group of neoplasms, accounting for approximatively 0.5-1.5% of all head and neck tumors. Management of these neoplasms requires a careful diagnostic workout and an appropriate surgical approach to obtain good outcomes associated with minimal aesthetic drawbacks. In this study we investigated clinical onset, histologic features, surgical treatment outcomes, peri operative complications and follow up of 98 patients treated for PPS tumors in our Centre between 2002 and 2021. Furthermore, we reviewed our preliminary experience of preoperative embolization of hyper vascular PPS tumors trough SQUID12, an ethylene vinyl alcohol copolymers (EVOH) which exhibits many advantages over other embolic agents, due to its better devascularization rate and lower risk of systemic complications. Our data support the hypothesis that transoral surgery scenario should be significantly revised, as it could represent a valid treatment for tumors located in lower and prestyloyd portion of PPS. Moreover, SQUID12, a novel embolization agent, may be a very promising choice for PPS hyper vascularized tumors, ensuring higher devascularization rate, safer procedures and lower risk of systemic dispersion compared to traditional Contour treatment., Competing Interests: The Authors declare no conflict of interest.

Although vision loss is known to affect equilibrium maintenance, postural control in patients affected by low vision has been poorly investigated. We evaluated postural stability and the ability to use visual, proprioceptive and vestibular information in different low vision patterns. Ten adults with normal vision (NC), fourteen adults affected by central visual impairment (CLV) and eight adults affected by peripheral visual impairment (PLV) were enrolled in our study. Patients underwent visual, vestibular and postural evaluation (bedside examination, Computed Dynamic Posturograophy). Motor Control Tests were performed to analyze automatic postural adaptive responses elicited by unexpected postural disturbances. Clinical evaluations did not show abnormality in all patients. In the Sensory Organization Test, CLV and PLV patients performed more poorly in conditions 3-6 and 3-4, as compared to NC subjects. The condition 5 score was significantly lower in the CLV group with respect to the PLV patients. Composite equilibrium scores demonstrated significant differences between low-vision subjects vs. NC subjects. No differences were found for somatosensorial contribution. Visual afferences showed lower values in all visually impaired subjects, while vestibular contribution was lower in the CLV patients as compared to the NC and PLV patients. MCT latencies were significantly worse in the CLV subjects. In the low-vision patients, postural control was modified with a specific pattern of strategy adaptation. Different modulations of postural control and different adaptive responses seemed to characterize CLV patients as compared to PLV subjects.

Several studies identified hearing loss as a risk factor for aging-related processes, including neurodegenerative diseases, as dementia and age-related hearing loss (ARHL). Although the association between hearing impairment in midlife and ARHL has been widely documented by epidemiological and experimental studies, the molecular mechanisms underlying this association are not fully understood. In this study, we used an established animal model of ARHL (C57BL/6 mice) to evaluate if early noise-induced hearing loss (NIHL) could affect the onset or progression of age-related cochlear dysfunction. We found that hearing loss can exacerbate ARHL, damaging sensory-neural cochlear epithelium and causing synaptopathy. Moreover, we studied common pathological markers shared between hearing loss and ARHL, demonstrating that noise exposure can worsen/accelerate redox status imbalance [increase of reactive oxygen species (ROS) production, lipid peroxidation, and dysregulation of endogenous antioxidant response] and vascular dysfunction [increased expression of hypoxia-inducible factor-1alpha (HIF-1α) and vascular endothelial growth factor C (VEGFC)] in the cochlea. Unveiling the molecular mechanisms underlying the link between hearing loss and aging processes could be valuable to identify effective therapeutic strategies to limit the effect of environmental risk factors on age-related diseases., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Fetoni, Pisani, Rolesi, Paciello, Viziano, Moleti, Sisto, Troiani, Paludetti and Grassi.)

The cross-talk between oxidative stress and inflammation seems to play a key role in noise-induced hearing loss. Several studies have addressed the role of PPAR receptors in mediating antioxidant and anti-inflammatory effects and, although its protective activity has been demonstrated in several tissues, less is known about how PPARs could be involved in cochlear dysfunction induced by noise exposure. In this study, we used an in vivo model of noise-induced hearing loss to investigate how oxidative stress and inflammation participate in cochlear dysfunction through PPAR signaling pathways. Specifically, we found a progressive decrease in PPAR expression in the cochlea after acoustic trauma, paralleled by an increase in oxidative stress and inflammation. By comparing an antioxidant (Q-ter) and an anti-inflammatory (Anakinra) treatment, we demonstrated that oxidative stress is the primary element of damage in noise-induced cochlear injury and that increased inflammation can be considered a consequence of PPAR down-regulation induced by ROS production. Indeed, by decreasing oxidative stress, PPARs returned to control values, reactivating the negative control on inflammation in a feedback loop.

Background: Although styrene is an established ototoxic agent at occupational exposure levels, the mechanisms of styrene toxicity in the auditory system are still unclear., Objectives: The aim of this study was to identify the consequences of styrene chronic exposure in cochlear structures, looking for the mechanisms of ototoxicity of this organic compound and focusing on cell targets and oxidative stress/inflammatory processes., Methods: Male adult Wistar rats were exposed to styrene (400 mg/kg by gavage for 5 days/week, 3 consecutive weeks). Hearing loss was evaluated by measuring auditory brainstem responses (ABR), morphological analysis were performed to evaluate hair cell and spiral ganglion neuron survival, as well as synaptic damage. Analysis of apoptotic (p53) and inflammatory (NF-κB, TNF-α, IL-1β and IL-10) mediators were performed by immunofluorescence analysis and western blot., Results: Styrene ototoxic effects induced a hearing loss of about 35-40 dB. Immunofluorescence and western blotting analyses demonstrated that styrene administration induced redox imbalance and activated inflammatory processes, targeting sensory hair cell and neural dysfunction by a cross-talk between oxidative and inflammatory mediators., Discussion: Major findings connect styrene ototoxicity to an interplay between redox imbalance and inflammation, leading to the intriguing assumption of a mixed sensory and neural styrene-induced ototoxicity. Thus, in a clinical perspective, data reported here have important implications for styrene risk assessment in humans., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Recent progress in hearing loss research has provided strong evidence for the imbalance of cellular redox status and inflammation as common predominant mechanisms of damage affecting the organ of Corti including noise induced hearing loss. The discovery of a protective molecule acting on both mechanisms is challenging. The thiazolidinediones, a class of antidiabetic drugs including pioglitazone and rosiglitazone, have demonstrated diverse pleiotrophic effects in many tissues where they exhibit anti-inflammatory, anti-proliferative, tissue protective effects and regulators of redox balance acting as agonist of peroxisome proliferator-activated receptors (PPARs). They are members of the family of ligand regulated nuclear hormone receptors that are also expressed in several cochlear cell types, including the outer hair cells. In this study, we investigated the protective capacity of pioglitazone in a model of noise-induced hearing loss in Wistar rats and the molecular mechanisms underlying this protective effects. Specifically, we employed a formulation of pioglitazone in a biocompatible thermogel providing rapid, uniform and sustained inner ear drug delivery via transtympanic injection. Following noise exposure (120 dB, 10 kHz, 1 h), different time schedules of treatment were employed: we explored the efficacy of pioglitazone given immediately (1 h) or at delayed time points (24 and 48 h) after noise exposure and the time course and extent of hearing recovery were assessed. We found that pioglitazone was able to protect auditory function at the mid-high frequencies and to limit cell death in the cochlear basal/middle turn, damaged by noise exposure. Immunofluorescence and western blot analysis provided evidence that pioglitazone mediates both anti-inflammatory and anti-oxidant effects by decreasing NF-κB and IL-1β expression in the cochlea and opposing the oxidative damage induced by noise insult. These results suggest that intratympanic pioglitazone can be considered a valid therapeutic strategy for attenuating noise-induced hearing loss and cochlear damage, reducing inflammatory signaling and restoring cochlear redox balance.

Background: Transcranial direct current stimulation (tDCS) is a non-invasive tool capable to modulate cortical functions by affecting neuronal excitability and synaptic plasticity., Objective: Here we investigated the effects of anodal tDCS on auditory cortex (ACx) in normal-hearing rats and following a paradigm of noise-induced hearing loss (NIHL), that causes morphological alterations in ACx pyramidal neurons., Methods: Male rats exposed to intense pure tone (10 kHz) were subsequently subjected to unilateral anodal tDCS of ACx and changes in dendritic morphology and spines were assessed by Golgi-Cox staining 30 days after the onset of the acoustic trauma. Molecular and functional changes were investigated by Western immunoblotting, immunofluorescence experiments and electrophysiological recordings in brain slices., Results: We found that NIHL altered dendritic morphology by decreasing spine density, mostly in layer 2/3 pyramidal neurons. Interestingly, tDCS increased ACx spine density, targeting apical dendrites of layer 2/3 and 5/6 pyramidal neurons in rats with normal auditory function and both apical and basal arborizations in layer 2/3 of NIHL rats. Twenty-four hours after tDCS, Bdnf and synaptophysin levels in ACx increased both in normal-hearing and noise-exposed rats. Field recordings showed that basal synaptic transmission at layer 2/3 horizontal connections was significantly reduced in noise-exposed rats compared to normal-hearing animals and, notably, input-output curves of noise-exposed animals subjected to tDCS were similar to those of normal-hearing rats., Conclusions: Our findings provide novel evidence that anodal tDCS affects structural plasticity in the ACx suggesting that it might be beneficial in treating cortical alterations due to cochlear damage., (Copyright © 2018 Elsevier Inc. All rights reserved.)