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Leichtle A, Lupatsii M, Graspeuntner S, Jeschke S, Penxová Z, Kurabi A, Ryan AF, Rupp J, Pries R, Bruchhage KL. Anti-inflammatory response to 1,8-Cineol and associated microbial communities in Otitis media patients. Sci Rep 2024; 14:16362. [PMID: 39014066 PMCID: PMC11252366 DOI: 10.1038/s41598-024-67498-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2024] [Accepted: 07/11/2024] [Indexed: 07/18/2024] Open
Abstract
Chronic Otitis Media (COM) is defined as long term inflammation and colonization with pathogenic bacteria due to a defect or retraction of the tympanic membrane. Surgical interventions are often augmented by antibiotic resistance development and therefore, off-label treatment using the natural drug 1,8-Cineol was carried out. All COM patients underwent antibiotic therapy and middle ear surgery and developed antibiotic resistances. Microbiological investigations from the auditory canal and stool samples were performed in correlation with the clinical course. Therapy of COM patients with 1,8-Cineol revealed a clear reduction of inflammatory microbes P. aeruginosa and Proteus mirabilis in ear samples as well as intestinal Prevotella copri, which was associated with an improved clinical outcome in certain individuals. The present off-label study revealed manifold anti-inflammatory effects of the natural monoterpene 1,8-Cineol in Otitis media patients. A better understanding of the underlying mechanisms will improve the current treatment options and possible forms of application of this natural drug.
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Affiliation(s)
- Anke Leichtle
- Department of Otorhinolaryngology, University of Luebeck, 23538, Lübeck, Germany
| | - Mariia Lupatsii
- Department of Infectious Diseases and Microbiology, University of Luebeck, Lübeck, Germany
| | - Simon Graspeuntner
- Department of Infectious Diseases and Microbiology, University of Luebeck, Lübeck, Germany
| | - Stephanie Jeschke
- Department of Otorhinolaryngology, University of Luebeck, 23538, Lübeck, Germany
| | - Zuzana Penxová
- Department of Otorhinolaryngology, University of Luebeck, 23538, Lübeck, Germany
| | - Arwa Kurabi
- Department of Surgery/ Otolaryngology, University of California San Diego, La Jolla, USA
| | - Allen Frederic Ryan
- Department of Surgery/ Otolaryngology, University of California San Diego, La Jolla, USA
| | - Jan Rupp
- Department of Infectious Diseases and Microbiology, University of Luebeck, Lübeck, Germany
| | - Ralph Pries
- Department of Otorhinolaryngology, University of Luebeck, 23538, Lübeck, Germany
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Gansemer BM, Rahman MT, Zhang Z, Green SH. Spiral ganglion neuron degeneration in aminoglycoside-deafened rats involves innate and adaptive immune responses not requiring complement. Front Mol Neurosci 2024; 17:1389816. [PMID: 38840777 PMCID: PMC11151750 DOI: 10.3389/fnmol.2024.1389816] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2024] [Accepted: 04/29/2024] [Indexed: 06/07/2024] Open
Abstract
Spiral ganglion neurons (SGNs) transmit auditory information from cochlear hair cells to the brain. SGNs are thus not only important for normal hearing, but also for effective functioning of cochlear implants, which stimulate SGNs when hair cells are missing. SGNs slowly degenerate following aminoglycoside-induced hair cell loss, a process thought to involve an immune response. However, the specific immune response pathways involved remain unknown. We used RNAseq to gain a deeper understanding immune-related and other transcriptomic changes that occur in the rat spiral ganglion after kanamycin-induced deafening. Among the immune and inflammatory genes that were selectively upregulated in deafened spiral ganglia, the complement cascade genes were prominent. We then assessed SGN survival, as well as immune cell numbers and activation, in the spiral ganglia of rats with a CRISPR-Cas9-mediated knockout of complement component 3 (C3). Similar to previous findings in our lab and other deafened rodent models, we observed an increase in macrophage number and increased expression of CD68, a marker of phagocytic activity and cell activation, in macrophages in the deafened ganglia. Moreover, we found an increase in MHCII expression on spiral ganglion macrophages and an increase in lymphocyte number in the deafened ganglia, suggestive of an adaptive immune response. However, C3 knockout did not affect SGN survival or increase in macrophage number/activation, implying that complement activation does not play a role in SGN death after deafening. Together, these data suggest that both innate and adaptive immune responses are activated in the deafened spiral ganglion, with the adaptive response directly contributing to cochlear neurodegeneration.
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Affiliation(s)
| | | | | | - Steven H. Green
- Department of Biology, University of Iowa, Iowa City, IA, United States
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3
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Liu W, Li H, Kämpfe Nordström C, Danckwardt-Lillieström N, Agrawal S, Ladak HM, Rask-Andersen H. Immuno-surveillance and protection of the human cochlea. Front Neurol 2024; 15:1355785. [PMID: 38817543 PMCID: PMC11137295 DOI: 10.3389/fneur.2024.1355785] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2023] [Accepted: 02/21/2024] [Indexed: 06/01/2024] Open
Abstract
Background Despite its location near infection-prone areas, the human inner ear demonstrates remarkable resilience. This suggests that there are inherent instruments deterring the invasion and spread of pathogens into the inner ear. Here, we combined high-resolution light microscopy, super-resolution immunohistochemistry (SR-SIM) and synchrotron phase contrast imaging (SR-PCI) to identify the protection and barrier systems in the various parts of the human inner ear, focusing on the lateral wall, spiral ganglion, and endolymphatic sac. Materials and methods Light microscopy was conducted on mid-modiolar, semi-thin sections, after direct glutaraldehyde/osmium tetroxide fixation. The tonotopic locations were estimated using SR-PCI and 3D reconstruction in cadaveric specimens. The sections were analyzed for leucocyte and macrophage activity, and the results were correlated with immunohistochemistry using confocal microscopy and SR-SIM. Results Light microscopy revealed unprecedented preservation of cell anatomy and several macrophage-like cells that were localized in the cochlea. Immunohistochemistry demonstrated IBA1 cells frequently co-expressing MHC II in the spiral ganglion, nerve fibers, lateral wall, spiral limbus, and tympanic covering layer at all cochlear turns as well as in the endolymphatic sac. RNAscope assays revealed extensive expression of fractalkine gene transcripts in type I spiral ganglion cells. CD4 and CD8 cells occasionally surrounded blood vessels in the modiolus and lateral wall. TMEM119 and P2Y12 were not expressed, indicating that the cells labeled with IBA1 were not microglia. The round window niche, compact basilar membrane, and secondary spiral lamina may form protective shields in the cochlear base. Discussion The results suggest that the human cochlea is surveilled by dwelling and circulating immune cells. Resident and blood-borne macrophages may initiate protective immune responses via chemokine signaling in the lateral wall, spiral lamina, and spiral ganglion at different frequency locations. Synchrotron imaging revealed intriguing protective barriers in the base of the cochlea. The role of the endolymphatic sac in human inner ear innate and adaptive immunity is discussed.
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Affiliation(s)
- Wei Liu
- Department of Surgical Sciences, Otorhinolaryngology and Head and Neck Surgery, Uppsala University, Uppsala, Sweden
| | - Hao Li
- Department of Surgical Sciences, Otorhinolaryngology and Head and Neck Surgery, Uppsala University, Uppsala, Sweden
| | - Charlotta Kämpfe Nordström
- Department of Surgical Sciences, Otorhinolaryngology and Head and Neck Surgery, Uppsala University, Uppsala, Sweden
| | | | - Sumit Agrawal
- Department of Otolaryngology-Head and Neck Surgery, Western University, London, ON, Canada
- Department of Medical Biophysics, Western University, London, ON, Canada
- Department of Electrical and Computer Engineering, Western University, London, ON, Canada
| | - Hanif M. Ladak
- Department of Otolaryngology-Head and Neck Surgery, Western University, London, ON, Canada
- Department of Medical Biophysics, Western University, London, ON, Canada
- Department of Electrical and Computer Engineering, Western University, London, ON, Canada
| | - Helge Rask-Andersen
- Department of Surgical Sciences, Otorhinolaryngology and Head and Neck Surgery, Uppsala University, Uppsala, Sweden
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Hirose K, Li SZ, Gill R, Hartsock J. Pneumococcal Meningitis Induces Hearing Loss and Cochlear Ossification Modulated by Chemokine Receptors CX3CR1 and CCR2. J Assoc Res Otolaryngol 2024; 25:179-199. [PMID: 38472515 PMCID: PMC11018586 DOI: 10.1007/s10162-024-00935-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2023] [Accepted: 01/12/2024] [Indexed: 03/14/2024] Open
Abstract
PURPOSE Pneumococcal meningitis is a major cause of hearing loss and permanent neurological impairment despite widely available antimicrobial therapies to control infection. Methods to improve hearing outcomes for those who survive bacterial meningitis remains elusive. We used a mouse model of pneumococcal meningitis to evaluate the impact of mononuclear phagocytes on hearing outcomes and cochlear ossification by altering the expression of CX3CR1 and CCR2 in these infected mice. METHODS We induced pneumococcal meningitis in approximately 500 C57Bl6 adult mice using live Streptococcus pneumoniae (serotype 3, 1 × 105 colony forming units (cfu) in 10 µl) injected directly into the cisterna magna of anesthetized mice and treated these mice with ceftriaxone daily until recovered. We evaluated hearing thresholds over time, characterized the cochlear inflammatory response, and quantified the amount of new bone formation during meningitis recovery. We used microcomputed tomography (microCT) scans to quantify cochlear volume loss caused by neo-ossification. We also performed perilymph sampling in live mice to assess the integrity of the blood-perilymph barrier during various time intervals after meningitis. We then evaluated the effect of CX3CR1 or CCR2 deletion in meningitis symptoms, hearing loss, macrophage/monocyte recruitment, neo-ossification, and blood labyrinth barrier function. RESULTS Sixty percent of mice with pneumococcal meningitis developed hearing loss. Cochlear fibrosis could be detected within 4 days of infection, and neo-ossification by 14 days. Loss of spiral ganglion neurons was common, and inner ear anatomy was distorted by scarring caused by new soft tissue and bone deposited within the scalae. The blood-perilymph barrier was disrupted at 3 days post infection (DPI) and was restored by seven DPI. Both CCR2 and CX3CR1 monocytes and macrophages were present in the cochlea in large numbers after infection. Neither chemokine receptor was necessary for the induction of hearing loss, cochlear fibrosis, ossification, or disruption of the blood-perilymph barrier. CCR2 knockout (KO) mice suffered the most severe hearing loss. CX3CR1 KO mice demonstrated an intermediate phenotype with greater susceptibility to hearing loss compared to control mice. Elimination of CX3CR1 mononuclear phagocytes during the first 2 weeks after meningitis in CX3CR1-DTR transgenic mice did not protect mice from any of the systemic or hearing sequelae of pneumococcal meningitis. CONCLUSIONS Pneumococcal meningitis can have devastating effects on cochlear structure and function, although not all mice experienced hearing loss or cochlear damage. Meningitis can result in rapid progression of hearing loss with fibrosis starting at four DPI and ossification within 2 weeks of infection detectable by light microscopy. The inflammatory response to bacterial meningitis is robust and can affect all three scalae. Our results suggest that CCR2 may assist in controlling infection and maintaining cochlear patency, as CCR2 knockout mice experienced more severe disease, more rapid hearing loss, and more advanced cochlear ossification after pneumococcal meningitis. CX3CR1 also may play an important role in the maintenance of cochlear patency.
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Affiliation(s)
- Keiko Hirose
- Department of Otolaryngology-Head and Neck Surgery, Washington University School of Medicine, 660 S. Euclid Avenue, Campus Box 8115, St. Louis, MO, 63110, USA.
| | - Song Zhe Li
- Department of Otolaryngology-Head and Neck Surgery, Washington University School of Medicine, 660 S. Euclid Avenue, Campus Box 8115, St. Louis, MO, 63110, USA
| | - Ruth Gill
- Department of Otolaryngology-Head and Neck Surgery, Washington University School of Medicine, 660 S. Euclid Avenue, Campus Box 8115, St. Louis, MO, 63110, USA
- Department of Obstetric and Gynecology, Washington University, St. Louis, MO, USA
| | - Jared Hartsock
- Department of Otolaryngology-Head and Neck Surgery, Washington University School of Medicine, 660 S. Euclid Avenue, Campus Box 8115, St. Louis, MO, 63110, USA
- Turner Scientific, Jacksonville, IL, USA
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Ohlemiller KK, Dwyer N, Henson V, Fasman K, Hirose K. A critical evaluation of "leakage" at the cochlear blood-stria-barrier and its functional significance. Front Mol Neurosci 2024; 17:1368058. [PMID: 38486963 PMCID: PMC10937559 DOI: 10.3389/fnmol.2024.1368058] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2024] [Accepted: 02/16/2024] [Indexed: 03/17/2024] Open
Abstract
The blood-labyrinth-barrier (BLB) is a semipermeable boundary between the vasculature and three separate fluid spaces of the inner ear, the perilymph, the endolymph and the intrastrial space. An important component of the BLB is the blood-stria-barrier, which shepherds the passage of ions and metabolites from strial capillaries into the intrastrial space. Some investigators have reported increased "leakage" from these capillaries following certain experimental interventions, or in the presence of inflammation or genetic variants. This leakage is generally thought to be harmful to cochlear function, principally by lowering the endocochlear potential (EP). Here, we examine evidence for this dogma. We find that strial capillaries are not exclusive, and that the asserted detrimental influence of strial capillary leakage is often confounded by hair cell damage or intrinsic dysfunction of the stria. The vast majority of previous reports speculate about the influence of strial vascular barrier function on the EP without directly measuring the EP. We argue that strial capillary leakage is common across conditions and species, and does not significantly impact the EP or hearing thresholds, either on evidentiary or theoretical grounds. Instead, strial capillary endothelial cells and pericytes are dynamic and allow permeability of varying degrees in response to specific conditions. We present observations from mice and demonstrate that the mechanisms of strial capillary transport are heterogeneous and inconsistent among inbred strains.
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Affiliation(s)
- Kevin K. Ohlemiller
- Department of Otolaryngology, Washington University School of Medicine, St. Louis, MO, United States
- Program in Communication Sciences and Audiology, Washington University School of Medicine, St. Louis, MO, United States
| | - Noël Dwyer
- Program in Communication Sciences and Audiology, Washington University School of Medicine, St. Louis, MO, United States
| | - Veronica Henson
- Program in Communication Sciences and Audiology, Washington University School of Medicine, St. Louis, MO, United States
| | - Kaela Fasman
- Program in Communication Sciences and Audiology, Washington University School of Medicine, St. Louis, MO, United States
| | - Keiko Hirose
- Department of Otolaryngology, Washington University School of Medicine, St. Louis, MO, United States
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Abou Assale T, Kuenzel T, Schink T, Shahraz A, Neumann H, Klaus C. 6'-sialyllactose ameliorates the ototoxic effects of the aminoglycoside antibiotic neomycin in susceptible mice. Front Immunol 2023; 14:1264060. [PMID: 38130726 PMCID: PMC10733791 DOI: 10.3389/fimmu.2023.1264060] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2023] [Accepted: 11/21/2023] [Indexed: 12/23/2023] Open
Abstract
Sialic acids are terminal sugars of the cellular glycocalyx and are highly abundant in the nervous tissue. Sialylation is sensed by the innate immune system and acts as an inhibitory immune checkpoint. Aminoglycoside antibiotics such as neomycin have been shown to activate tissue macrophages and induce ototoxicity. In this study, we investigated the systemic subcutaneous application of the human milk oligosaccharide 6'-sialyllactose (6SL) as a potential therapy for neomycin-induced ototoxicity in postnatal mice. Repeated systemic treatment of mice with 6SL ameliorated neomycin-induced hearing loss and attenuated neomycin-triggered macrophage activation in the cochlear spiral ganglion. In addition, 6SL reversed the neomycin-mediated increase in gene transcription of the pro-inflammatory cytokine interleukin-1β (Il-1b) and the apoptotic/inflammatory kinase Pik3cd in the inner ear. Interestingly, neomycin application also increased the transcription of desialylating enzyme neuraminidase 3 (Neu3) in the inner ear. In vitro, we confirmed that treatment with 6SL had anti-inflammatory, anti-phagocytic, and neuroprotective effects on cultured lipopolysaccharide-challenged human THP1-macrophages. Thus, our data demonstrated that treatment with 6SL has anti-inflammatory and protective effects against neomycin-mediated macrophage activation and ototoxicity.
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Affiliation(s)
- Tawfik Abou Assale
- Neural Regeneration, Institute of Reconstructive Neurobiology, Medical Faculty and University Hospital of Bonn, University of Bonn, Bonn, Germany
| | - Thomas Kuenzel
- Auditory Neurophysiology, Department of Chemosensation, Institute for Biology II, RWTH Aachen University, Aachen, Germany
| | - Tamara Schink
- Neural Regeneration, Institute of Reconstructive Neurobiology, Medical Faculty and University Hospital of Bonn, University of Bonn, Bonn, Germany
| | - Anahita Shahraz
- Neural Regeneration, Institute of Reconstructive Neurobiology, Medical Faculty and University Hospital of Bonn, University of Bonn, Bonn, Germany
| | - Harald Neumann
- Neural Regeneration, Institute of Reconstructive Neurobiology, Medical Faculty and University Hospital of Bonn, University of Bonn, Bonn, Germany
| | - Christine Klaus
- Neural Regeneration, Institute of Reconstructive Neurobiology, Medical Faculty and University Hospital of Bonn, University of Bonn, Bonn, Germany
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7
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Chen CP, Chen PC, Pan YL, Hsu YC. Prenatal lipopolysaccharide exposure induces anxiety-like behaviour in male mouse offspring and aberrant glial differentiation of embryonic neural stem cells. Cell Mol Biol Lett 2023; 28:67. [PMID: 37592237 PMCID: PMC10436442 DOI: 10.1186/s11658-023-00480-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2023] [Accepted: 07/26/2023] [Indexed: 08/19/2023] Open
Abstract
BACKGROUND Prenatal infection has been implicated in the development of neuropsychiatric disorders in children. We hypothesised that exposure to lipopolysaccharide during prenatal development could induce anxiety-like behaviour and sensorineural hearing loss in offspring, as well as disrupt neural differentiation during embryonic neural development. METHODS We simulated prenatal infection in FVB mice and mouse embryonic stem cell (ESC) lines, specifically 46C and E14Tg2a, through lipopolysaccharide treatment. Gene expression profiling analyses and behavioural tests were utilized to study the effects of lipopolysaccharide on the offspring and alterations in toll-like receptor (TLR) 2-positive and TLR4-positive cells during neural differentiation in the ESCs. RESULTS Exposure to lipopolysaccharide (25 µg/kg) on gestation day 9 resulted in anxiety-like behaviour specifically in male offspring, while no effects were detected in female offspring. We also found significant increases in the expression of GFAP and CNPase, as well as higher numbers of GFAP + astrocytes and O4+ oligodendrocytes in the prefrontal cortex of male offspring. Furthermore, increased scores for genes related to oligodendrocyte and lipid metabolism, particularly ApoE, were observed in the prefrontal cortex regions. Upon exposure to lipopolysaccharide during the ESC-to-neural stem cell (NSC) transition, Tuj1, Map2, Gfap, O4, and Oligo2 mRNA levels increased in the differentiated neural cells on day 14. In vitro experiments demonstrated that lipopolysaccharide exposure induced inflammatory responses, as evidenced by increased expression of IL1b and ApoB mRNA. CONCLUSIONS Our findings suggest that prenatal infection at different stages of neural differentiation may result in distinct disturbances in neural differentiation during ESC-NSC transitions. Furthermore, early prenatal challenges with lipopolysaccharide selectively induce anxiety-like behaviour in male offspring. This behaviour may be attributed to the abnormal differentiation of astrocytes and oligodendrocytes in the brain, potentially mediated by ApoB/E signalling pathways in response to inflammatory stimuli.
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Affiliation(s)
- Chie-Pein Chen
- Division of High Risk Pregnancy, Department of Obstetrics and Gynecology, MacKay Memorial Hospital, Taipei, Taiwan
- Department of Medical Research, MacKay Memorial Hospital, Taipei, Taiwan
| | - Pei-Chun Chen
- Department of Medical Research, MacKay Memorial Hospital, Taipei, Taiwan
| | - Yu-Ling Pan
- Department of Audiology and Speech-Language Pathology, MacKay Medical College, New Taipei City, Taiwan
| | - Yi-Chao Hsu
- Department of Audiology and Speech-Language Pathology, MacKay Medical College, New Taipei City, Taiwan.
- Institute of Biomedical Sciences, MacKay Medical College, New Taipei City, Taiwan.
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8
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Rahman MT, Bailey EM, Gansemer BM, Pieper AA, Manak JR, Green SH. Anti-inflammatory Therapy Protects Spiral Ganglion Neurons After Aminoglycoside Antibiotic-Induced Hair Cell Loss. Neurotherapeutics 2023; 20:578-601. [PMID: 36697994 PMCID: PMC10121993 DOI: 10.1007/s13311-022-01336-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/06/2022] [Indexed: 01/26/2023] Open
Abstract
Destruction of cochlear hair cells by aminoglycoside antibiotics leads to gradual death of the spiral ganglion neurons (SGNs) that relay auditory information to the brain, potentially limiting the efficacy of cochlear implants. Because the reasons for this cochlear neurodegeneration are unknown, there are no neuroprotective strategies for patients. To investigate this problem, we assessed transcriptomic changes in the rat spiral ganglion following aminoglycoside antibiotic (kanamycin)-induced hair cell destruction. We observed selectively increased expression of immune and inflammatory response genes and increased abundance of activated macrophages in spiral ganglia by postnatal day 32 in kanamycin-deafened rats, preceding significant SGN degeneration. Treatment with the anti-inflammatory medications dexamethasone and ibuprofen diminished long-term SGN degeneration. Ibuprofen and dexamethasone also diminished macrophage activation. Efficacy of ibuprofen treatment was augmented by co-administration of the nicotinamide adenine dinucleotide-stabilizing agent P7C3-A20. Our results support a critical role of neuroinflammation in SGN degeneration after aminoglycoside antibiotic-mediated cochlear hair cell loss, as well as a neuroprotective strategy that could improve cochlear implant efficacy.
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Affiliation(s)
- Muhammad T Rahman
- Department of Biology, University of Iowa, Iowa City, IA, 52242, USA
| | - Erin M Bailey
- Department of Biology, University of Iowa, Iowa City, IA, 52242, USA
| | | | - Andrew A Pieper
- Harrington Discovery Institute, University Hospitals Cleveland Medical Center, Cleveland, OH, 44106, USA
- Department of Psychiatry, Case Western Reserve University, Cleveland, OH, 44106, USA
- Geriatric Psychiatry, GRECC, Louis Stokes Cleveland VA Medical Center, Cleveland, OH, 44106, USA
- Institute for Transformative Molecular Medicine, School of Medicine, Case Western Reserve University, Cleveland, OH, 44106, USA
| | - J Robert Manak
- Department of Biology, University of Iowa, Iowa City, IA, 52242, USA
- Department of Pediatrics, University of Iowa, Iowa City, IA, 52242, USA
| | - Steven H Green
- Department of Biology, University of Iowa, Iowa City, IA, 52242, USA.
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Fallon JB, Dueck W, Trang EP, Smyth D, Wise AK. Effects of chronic implantation and long-term stimulation of a cochlear implant in the partial hearing cat model. Hear Res 2022; 426:108470. [PMID: 35249777 DOI: 10.1016/j.heares.2022.108470] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/16/2021] [Revised: 01/23/2022] [Accepted: 02/21/2022] [Indexed: 12/16/2022]
Abstract
The expansion of criteria for cochlear implantation has resulted in increasing numbers of cochlear implant subjects having some level of residual hearing. The present study examined the effects of implantation surgery and long-term electrical stimulation on residual hearing in a partially deafened cat model. Eighteen animals were partially deafened, implanted and chronically stimulated. Implantation resulted in a pronounced loss evident 2-weeks post implantation of up to 30-40 dB at 4 & 8 kHz which was statistically significant (2-way RM ANOVA (Time, Frequency): p(Time) = 0.001; p(Frequency) < 0.001; p(Time x Frequency) < 0.001)). Chronic stimulation resulted in a significant (RM ANOVA: p(Time) = 0.030) ongoing hearing loss, with 5 animals (∼30%) exhibiting an increase in threshold of 20 dB or more. Different loss profiles were evident with peripheral and central hearing assessments suggests that changes in 'central gain' may be occurring. Despite significant loss of hair cells and spiral ganglion neurons and distinct fibrous tissue growth in the scala tympani following implantation and long-term electrical stimulation, there were no significant correlations with any histological measures and ongoing hearing loss. The partially deafened, chronically stimulated cat model provides a clinically relevant model in which to further investigate the cause of the delayed hearing loss following cochlear implant surgery and use.
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Affiliation(s)
- James B Fallon
- Bionics Institute, Victoria, Australia; Medical Bionics Department, University of Melbourne, Victoria, Australia.
| | | | | | | | - Andrew K Wise
- Bionics Institute, Victoria, Australia; Medical Bionics Department, University of Melbourne, Victoria, Australia
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10
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Claussen AD, Quevedo RV, Kirk JR, Higgins T, Mostaert B, Rahman MT, Oleson J, Hernandez R, Hirose K, Hansen MR. Chronic cochlear implantation with and without electric stimulation in a mouse model induces robust cochlear influx of CX3CR1 +/GFP macrophages. Hear Res 2022; 426:108510. [PMID: 35527124 PMCID: PMC9596618 DOI: 10.1016/j.heares.2022.108510] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/28/2021] [Revised: 03/27/2022] [Accepted: 04/23/2022] [Indexed: 12/16/2022]
Abstract
BACKGROUND Cochlear implantation is an effective auditory rehabilitation strategy for those with profound hearing loss, including those with residual low frequency hearing through use of hybrid cochlear implantation techniques. Post-mortem studies demonstrate the nearly ubiquitous presence of intracochlear fibrosis and neo-ossification following cochlear implantation. Current evidence suggests post-implantation intracochlear fibrosis is associated with delayed loss of residual acoustic hearing in hybrid cochlear implant (CI) recipients and may also negatively influence outcomes in traditional CI recipients. This study examined the contributions of surgical trauma, foreign body response and electric stimulation to intracochlear fibrosis and the innate immune response to cochlear implantation and the hierarchy of these contributions. METHODS Normal hearing CX3CR1+/GFP mice underwent either round window opening (sham), acute CI insertion or chronic CI insertion with no, low- or high-level electric stimulation. Electric stimulation levels were based on neural response telemetry (NRT), beginning post-operative day 7 for 5 h per day. Subjects (n=3 per timepoint) were sacrificed at 4 h, 1,4,7,8,11,14 and 21 days. An unoperated group (n=3) served as controls. Cochleae were harvested at each time-point and prepared for immunohistochemistry with confocal imaging. The images were analyzed to obtain CX3CR1+ macrophage cell number and density in the lateral wall (LW), scala tympani (ST) and Rosenthal's canal (RC). RESULTS A ST peri-implant cellular infiltrate and fibrosis occurred exclusively in the chronically implanted groups starting on day 7 with a concurrent infiltration of CX3CR1+ macrophages not seen in the other groups. CX3CR1+ macrophage infiltration was seen in the LW and RC in all experimental groups within the first week, being most prominent in the 3 chronically implanted groups during the second and third week. CONCLUSIONS The cochlear immune response was most prominent in the presence of chronic cochlear implantation, regardless of electric stimulation level. Further, the development of intracochlear ST fibrosis was dependent on the presence of the indwelling CI foreign body. An innate immune response was evoked by surgical trauma alone (sham and acute CI groups) to a lesser degree. These data suggest that cochlear inflammation and intrascalar fibrosis after cochlear implantation are largely dependent on the presence of a chronic indwelling foreign body and are not critically dependent on electrical stimulation. Also, these data support a role for surgical trauma in inciting the initial innate immune response.
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Affiliation(s)
- Alexander D Claussen
- Department of Otolaryngology Head and Neck Surgery, University of Iowa, Iowa City, IA 52242, United States; Department of Otolaryngology Head and Neck Surgery, University of California San Diego, San Diego, CA 92103, United States.
| | - René Vielman Quevedo
- Department of Otolaryngology Head and Neck Surgery, University of Iowa, Iowa City, IA 52242, United States; Department of Biomedical Sciences, Creighton University, Omaha, NE 68178, United States
| | | | - Timon Higgins
- Department of Otolaryngology Head and Neck Surgery, University of Iowa, Iowa City, IA 52242, United States
| | - Brian Mostaert
- Department of Otolaryngology Head and Neck Surgery, University of Iowa, Iowa City, IA 52242, United States
| | - Muhammad Taifur Rahman
- Department of Otolaryngology Head and Neck Surgery, University of Iowa, Iowa City, IA 52242, United States
| | - Jacob Oleson
- Department of Biostatistics, College of Public Health, University of Iowa, Iowa City, IA 52242, United States
| | - Reyna Hernandez
- Department of Biostatistics, College of Public Health, University of Iowa, Iowa City, IA 52242, United States
| | - Keiko Hirose
- Department of Otolaryngology Head and Neck Surgery, Washington University School of Medicine, St. Louis, MO 63110, United States
| | - Marlan R Hansen
- Department of Otolaryngology Head and Neck Surgery, University of Iowa, Iowa City, IA 52242, United States
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Coffin AB, Dale E, Doppenberg E, Fearington F, Hayward T, Hill J, Molano O. Putative COVID-19 therapies imatinib, lopinavir, ritonavir, and ivermectin cause hair cell damage: A targeted screen in the zebrafish lateral line. Front Cell Neurosci 2022; 16:941031. [PMID: 36090793 PMCID: PMC9448854 DOI: 10.3389/fncel.2022.941031] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2022] [Accepted: 07/29/2022] [Indexed: 11/13/2022] Open
Abstract
The biomedical community is rapidly developing COVID-19 drugs to bring much-need therapies to market, with over 900 drugs and drug combinations currently in clinical trials. While this pace of drug development is necessary, the risk of producing therapies with significant side-effects is also increased. One likely side-effect of some COVID-19 drugs is hearing loss, yet hearing is not assessed during preclinical development or clinical trials. We used the zebrafish lateral line, an established model for drug-induced sensory hair cell damage, to assess the ototoxic potential of seven drugs in clinical trials for treatment of COVID-19. We found that ivermectin, lopinavir, imatinib, and ritonavir were significantly toxic to lateral line hair cells. By contrast, the approved COVID-19 therapies dexamethasone and remdesivir did not cause damage. We also did not observe damage from the antibiotic azithromycin. Neither lopinavir nor ritonavir altered the number of pre-synaptic ribbons per surviving hair cell, while there was an increase in ribbons following imatinib or ivermectin exposure. Damage from lopinavir, imatinib, and ivermectin was specific to hair cells, with no overall cytotoxicity noted following TUNEL labeling. Ritonavir may be generally cytotoxic, as determined by an increase in the number of TUNEL-positive non-hair cells following ritonavir exposure. Pharmacological inhibition of the mechanotransduction (MET) channel attenuated damage caused by lopinavir and ritonavir but did not alter imatinib or ivermectin toxicity. These results suggest that lopinavir and ritonavir may enter hair cells through the MET channel, similar to known ototoxins such as aminoglycoside antibiotics. Finally, we asked if ivermectin was ototoxic to rats in vivo. While ivermectin is not recommended by the FDA for treating COVID-19, many people have chosen to take ivermectin without a doctor’s guidance, often with serious side-effects. Rats received daily subcutaneous injections for 10 days with a clinically relevant ivermectin dose (0.2 mg/kg). In contrast to our zebrafish assays, ivermectin did not cause ototoxicity in rats. Our research suggests that some drugs in clinical trials for COVID-19 may be ototoxic. This work can help identify drugs with the fewest side-effects and determine which therapies warrant audiometric monitoring.
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Affiliation(s)
- Allison B. Coffin
- Department of Integrative Physiology and Neuroscience, Washington State University, Vancouver, WA, United States
- College of Arts and Sciences, Washington State University, Vancouver, WA, United States
- *Correspondence: Allison B. Coffin,
| | - Emily Dale
- College of Arts and Sciences, Washington State University, Vancouver, WA, United States
| | - Emilee Doppenberg
- College of Arts and Sciences, Washington State University, Vancouver, WA, United States
| | - Forrest Fearington
- College of Arts and Sciences, Washington State University, Vancouver, WA, United States
| | - Tamasen Hayward
- College of Arts and Sciences, Washington State University, Vancouver, WA, United States
| | - Jordan Hill
- College of Arts and Sciences, Washington State University, Vancouver, WA, United States
| | - Olivia Molano
- College of Arts and Sciences, Washington State University, Vancouver, WA, United States
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12
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Lee SY, Kim S, Han K, Woong Choi J, Byung Chae H, Yeon Choi D, Min Lee S, Kyun Park M, Mun S, Koo JW. Microarray analysis of lipopolysaccharide-induced endotoxemia in the cochlea. Gene 2022; 823:146347. [PMID: 35227853 DOI: 10.1016/j.gene.2022.146347] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2021] [Revised: 02/06/2022] [Accepted: 02/15/2022] [Indexed: 11/24/2022]
Abstract
Lipopolysaccharide (LPS)-induced endotoxemia alters intracochlear homeostasis and potentiates aminoglycoside-induced ototoxicity. However, the pathological mechanisms in the cochlea following systemic LPS-induced inflammation are unclear. In this study, three groups of mice received intraperitoneal injections [group A, saline control (n = 10); group B, 1 mg/kg LPS (n = 10); group C, 10 mg/kg LPS (n = 10)]. After 24 h, gene expression in cochlea samples was analyzed using DNA microarrays covering 28,853 genes in a duplicate manner. A total of 505 differentially expressed genes (DEGs) (≥2.0-fold change; p < 0.05) were identified. Interferon- and chemotaxis-related genes, including gbp2, gbp5, cxcl10, and Rnf125, were dose-dependently upregulated by LPS-induced endotoxemia. These results were verified by RT-qPCR. Upregulated DEGs were associated with inflammation, positive regulation of immune responses, and regulation of cell adhesion, while downregulated ones were associated with chemical synaptic transmission and the synaptic vesicle cycle. Protein-protein interaction included four functional clusters associated with interleukin-4, -10, and -13 and G protein-coupled receptor (GPCR) ligand binding; activation of matrix metalloproteinases and collagen degradation; recruitment of amyloid A proteins; and neutrophil degranulation. The findings of this study provide an additional basis on changes in the expression of genes in the cochlea in response to LPS-induced endotoxemia.
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Affiliation(s)
- Sang-Yeon Lee
- Department of Otorhinolaryngology-Head and Neck Surgery, Seoul National University Hospital, Seoul National University College of Medicine, Seoul, South Korea; Sensory Organ Research Institute, Seoul National University Medical Research Center, South Korea
| | - Songmi Kim
- Center for Bio-Medical Engineering Core Facility, Dankook University, Cheonan 31116, South Korea; Department of Microbiology, College of Science and Technology, Dankook University, Cheonan 31116, South Korea
| | - Kyudong Han
- Center for Bio-Medical Engineering Core Facility, Dankook University, Cheonan 31116, South Korea; Department of Microbiology, College of Science and Technology, Dankook University, Cheonan 31116, South Korea
| | - Jin Woong Choi
- Department of Otorhinolaryngology-Head and Neck Surgery, Chungnam National University, College of Medicine, Daejeon, South Korea
| | - Ho Byung Chae
- Department of Otorhinolaryngology-Head and Neck Surgery, Seoul National University Bundang Hospital, Seoul National University College of Medicine, Seongnam, South Korea
| | - Da Yeon Choi
- Department of Otorhinolaryngology-Head and Neck Surgery, Seoul National University Hospital, Seoul National University College of Medicine, Seoul, South Korea
| | - So Min Lee
- Department of Otorhinolaryngology-Head and Neck Surgery, Seoul National University Hospital, Seoul National University College of Medicine, Seoul, South Korea
| | - Moo Kyun Park
- Department of Otorhinolaryngology-Head and Neck Surgery, Seoul National University Hospital, Seoul National University College of Medicine, Seoul, South Korea
| | - Seyoung Mun
- Center for Bio-Medical Engineering Core Facility, Dankook University, Cheonan 31116, South Korea; Department of Nanobiomedical Science & BK21 PLUS NBM Global Research Center for Regenerative Medicine, Dankook University, Cheonan 31116, South Korea.
| | - Ja-Won Koo
- Department of Otorhinolaryngology-Head and Neck Surgery, Seoul National University Bundang Hospital, Seoul National University College of Medicine, Seongnam, South Korea; Sensory Organ Research Institute, Seoul National University Medical Research Center, South Korea.
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13
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Keithley EM. Inner ear immunity. Hear Res 2022; 419:108518. [DOI: 10.1016/j.heares.2022.108518] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/22/2021] [Revised: 05/06/2022] [Accepted: 05/10/2022] [Indexed: 11/26/2022]
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14
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Immunomodulatory Potential of Diuretics. BIOLOGY 2021; 10:biology10121315. [PMID: 34943230 PMCID: PMC8698805 DOI: 10.3390/biology10121315] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 11/01/2021] [Revised: 11/25/2021] [Accepted: 12/09/2021] [Indexed: 12/15/2022]
Abstract
In this review, diuretics and their immunomodulatory functions are described. The effects on the immune response of this group of drugs are reported in patients suffering from hypertension and under experimental conditions involving animal models and cell line studies. The pathogenesis of hypertension is strongly connected to chronic inflammation. The vast majority of diuretics modulate the immune response, changing it in favor of the anti-inflammatory response, but depending on the drug, these effects may differ. This topic is significantly important in medical practice regarding the treatment of patients who have coexisting diseases with chronic inflammatory pathogenesis, including hypertension or chronic heart failure. In patients with metabolic syndrome, allergies, or autoimmune disorders, the anti-inflammatory effect is favorable, because of the overstimulation of their immune system. Otherwise, in the geriatric population, it is important to find the proper anti- and pro-inflammatory balance to avoid an enhancement of immune response suppression, which can result in reducing the risk of serious infections that can occur due to the age-diminished function of the immune system. This article is intended to facilitate the selection of an antihypertensive drug that depends on the patient's immune situation.
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15
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Liu W, Danckwardt-Lillieström N, Schrott-Fischer A, Glueckert R, Rask-Andersen H. Distribution of Immune Cells Including Macrophages in the Human Cochlea. Front Neurol 2021; 12:781702. [PMID: 34880828 PMCID: PMC8645652 DOI: 10.3389/fneur.2021.781702] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2021] [Accepted: 10/21/2021] [Indexed: 12/20/2022] Open
Abstract
Background: The human cochlea was earlier believed to lack capacity to mount specific immune responses. Recent studies established that the human cochlea holds macrophages. The cells appear to surveil, dispose of, and restore wasted cells to maintain tissue integrity. Macrophage activities are believed to be the central elements in immune responses and could swiftly defuse invading microbes that enter via adjacent infection-prone areas. This review updates recent human studies in light of the current literature and adds information about chemokine gene expression. Materials and Methods: We analyzed surgically obtained human tissue using immunohistochemistry, confocal microscopy, and multichannel super-resolution structured illumination microscopy. The samples were considered representative of steady-state conditions. Antibodies against the ionized calcium-binding adaptor molecule 1 were used to identify the macrophages. CD68 and CD11b, and the major histocompatibility complex type II (MHCII) and CD4 and CD8 were analyzed. The RNAscope technique was used for fractalkine gene localization. Results: Many macrophages were found around blood vessels in the stria vascularis but not CD4 and CD8 lymphocytes. Amoeboid macrophages were identified in the spiral ganglion with surveilling "antennae" projecting against targeted cells. Synapse-like contacts were seen on spiral ganglion cell bodies richly expressing single CXC3CL gene transcripts. Branching neurite-like processes extended along central and peripheral axons. Active macrophages were occasionally found near degenerating hair cells. Some macrophage-interacting T lymphocytes were observed between the scala tympani wall and Rosenthal's canal. CD4 and CD8 cells were not found in the organ of Corti. Conclusions: The results indicate that the human cochlea is equipped with macrophages and potentially lymphocytes, suggesting both an innate and adaptive immune capacity. A rich expression of fractalkine gene transcripts in spiral ganglion neurons suggest an essential role for auditory nerve protection, as has been demonstrated experimentally. The findings provide further information on the important role of the immune machinery present in the human inner ear and its potential to carry adverse immune reactions, including cytotoxic and foreign body responses. The results can be used to form a rationale for therapies aiming to modulate these immune activities.
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Affiliation(s)
- Wei Liu
- Department of Surgical Sciences, Section of Otorhinolaryngology and Head and Neck Surgery, Uppsala University, Uppsala, Sweden
| | - Niklas Danckwardt-Lillieström
- Department of Surgical Sciences, Section of Otorhinolaryngology and Head and Neck Surgery, Uppsala University, Uppsala, Sweden
| | - Anneliese Schrott-Fischer
- Inner Ear Laboratory, Department of Otorhinolaryngology, Medical University Innsbruck, Innsbruck, Austria
| | - Rudolf Glueckert
- Inner Ear Laboratory, Department of Otorhinolaryngology, Medical University Innsbruck, Innsbruck, Austria
| | - Helge Rask-Andersen
- Department of Surgical Sciences, Section of Otorhinolaryngology and Head and Neck Surgery, Uppsala University, Uppsala, Sweden
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16
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Yang CH, Hwang CF, Chuang JH, Lian WS, Wang FS, Yang MY. Systemic toll-like receptor 9 agonist CpG oligodeoxynucleotides exacerbates aminoglycoside ototoxicity. Hear Res 2021; 411:108368. [PMID: 34678647 DOI: 10.1016/j.heares.2021.108368] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/01/2021] [Revised: 09/20/2021] [Accepted: 10/01/2021] [Indexed: 02/08/2023]
Abstract
The Toll-like receptor (TLR) signaling pathway is the key regulator of the innate immune system in response to systemic infection. Several studies have reported that the systemic TLR4 agonist lipopolysaccharide exacerbates aminoglycoside ototoxicity, but the influence of virus-associated TLR7 and TLR9 signaling cascades on the cochlea is unclear. The present study aimed to investigate the auditory effects of systemic TLR7 and TLR9 agonists during chronic kanamycin treatment. CBA/CaJ mice received the TLR7 agonist gardiquimod or TLR9 agonist CpG oligodeoxynucleotides (ODN) one day before kanamycin injection and on the 5th and 10th days during a 14-day course of kanamycin treatment. We observed that systemic gardiquimod or CpG ODN alone did not affect the baseline auditory brainstem response (ABR) threshold. Three weeks after kanamycin treatment, gardiquimod did not significantly change ABR threshold shifts, whereas CpG ODN significantly increased kanamycin-induced ABR threshold shifts. Furthermore, outer hair cell (OHC) evaluation revealed that CpG ODN reduced distortion product otoacoustic emission amplitudes and increased kanamycin-induced OHC loss. CpG ODN significantly elevated cochlear Irf-7, Tnf-α, Il-1, and Il-6 transcript levels. In addition, an increased number of Iba-1+ cells, which represented activated macrophages, was observed in the cochlea treated with CpG ODN. Our results indicated that systemic CpG ODN exacerbated kanamycin-induced ototoxicity and increased cochlear inflammation. This study implies that patients with underlying virus infection may experience more severe aminoglycoside-induced hearing loss if it occurs.
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Affiliation(s)
- Chao-Hui Yang
- Department of Otolaryngology, Kaohsiung Chang Gung Memorial Hospital and Chang Gung University College of Medicine, Kaohsiung 83301, Taiwan
| | - Chung-Feng Hwang
- Department of Otolaryngology, Kaohsiung Chang Gung Memorial Hospital and Chang Gung University College of Medicine, Kaohsiung 83301, Taiwan
| | - Jiin-Haur Chuang
- Division of Pediatric Surgery, Kaohsiung Chang Gung Memorial Hospital and Chang Gung University College of Medicine, Kaohsiung 83301, Taiwan; Graduate Institute of Clinical Medical Sciences, College of Medicine, Chang Gung University, Tao-Yuan 33302, Taiwan
| | - Wei-Shiung Lian
- Core Laboratory for Phenomics & Diagnostics, Department of Medical Research, Kaohsiung Chang Gung Memorial Hospital and Chang Gung University College of Medicine, Kaohsiung 83301, Taiwan
| | - Feng-Sheng Wang
- Graduate Institute of Clinical Medical Sciences, College of Medicine, Chang Gung University, Tao-Yuan 33302, Taiwan; Core Laboratory for Phenomics & Diagnostics, Department of Medical Research, Kaohsiung Chang Gung Memorial Hospital and Chang Gung University College of Medicine, Kaohsiung 83301, Taiwan
| | - Ming-Yu Yang
- Department of Otolaryngology, Kaohsiung Chang Gung Memorial Hospital and Chang Gung University College of Medicine, Kaohsiung 83301, Taiwan; Graduate Institute of Clinical Medical Sciences, College of Medicine, Chang Gung University, Tao-Yuan 33302, Taiwan.
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17
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Zhang Y, Li Y, Fu X, Wang P, Wang Q, Meng W, Wang T, Yang J, Chai R. The Detrimental and Beneficial Functions of Macrophages After Cochlear Injury. Front Cell Dev Biol 2021; 9:631904. [PMID: 34458249 PMCID: PMC8385413 DOI: 10.3389/fcell.2021.631904] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2020] [Accepted: 07/14/2021] [Indexed: 12/20/2022] Open
Abstract
Macrophages are the main intrinsic immune cells in the cochlea; they can be activated and play a complicated role after cochlear injury. Many studies have shown that the number of macrophages and their morphological characteristics within the major cochlear partitions undergo significant changes under various pathological conditions including acoustic trauma, ototoxic drug treatment, age-related cochlear degeneration, selective hair cell (HC) and spiral ganglion neuron (SGN) elimination, and surgery. However, the exact role of these macrophages after cochlear injury is still unclear. Regulating the migration and activity of macrophages may be a therapeutic approach to reduce the risk or magnitude of trauma-induced hearing loss, and this review highlights the role of macrophages on the peripheral auditory structures of the cochlea and elucidate the mechanisms of macrophage injury and the strategies to reduce the injury by regulating macrophage.
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Affiliation(s)
- Yuan Zhang
- MOE Key Laboratory for Developmental Genes and Human Disease, Jiangsu Province High-Tech Key Laboratory for Bio-Medical Research, School of Life Sciences and Technology, Southeast University, Nanjing, China.,Department of Otolaryngology Head and Neck, Nanjing Tongren Hospital, School of Medicine, Southeast University, Nanjing, China.,Co-innovation Center of Neuroregeneration, Nantong University, Nantong, China
| | - Yiyuan Li
- MOE Key Laboratory for Developmental Genes and Human Disease, Jiangsu Province High-Tech Key Laboratory for Bio-Medical Research, School of Life Sciences and Technology, Southeast University, Nanjing, China
| | - Xiaolong Fu
- MOE Key Laboratory for Developmental Genes and Human Disease, Jiangsu Province High-Tech Key Laboratory for Bio-Medical Research, School of Life Sciences and Technology, Southeast University, Nanjing, China
| | - Pengjun Wang
- Department of Otorhinolaryngology, Affiliated Sixth People's Hospital of Shanghai Jiao Tong University, Shanghai, China
| | - Qin Wang
- Department of Otolaryngology-Head and Neck Surgery, The Second Xiangya Hospital, Central South University, Changsha, China
| | - Wei Meng
- Department of Otolaryngology Head and Neck, Nanjing Tongren Hospital, School of Medicine, Southeast University, Nanjing, China
| | - Tian Wang
- Department of Otolaryngology-Head and Neck Surgery, The Second Xiangya Hospital, Central South University, Changsha, China
| | - Jianming Yang
- Department of Otorhinolaryngology, The Second Affiliated Hospital of Anhui Medical University, Hefei, China
| | - Renjie Chai
- MOE Key Laboratory for Developmental Genes and Human Disease, Jiangsu Province High-Tech Key Laboratory for Bio-Medical Research, School of Life Sciences and Technology, Southeast University, Nanjing, China.,Co-innovation Center of Neuroregeneration, Nantong University, Nantong, China.,Institute for Stem Cell and Regeneration, Chinese Academy of Sciences, Beijing, China
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18
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Stothert AR, Kaur T. Innate Immunity to Spiral Ganglion Neuron Loss: A Neuroprotective Role of Fractalkine Signaling in Injured Cochlea. Front Cell Neurosci 2021; 15:694292. [PMID: 34408629 PMCID: PMC8365835 DOI: 10.3389/fncel.2021.694292] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2021] [Accepted: 07/14/2021] [Indexed: 12/20/2022] Open
Abstract
Immune system dysregulation is increasingly being attributed to the development of a multitude of neurodegenerative diseases. This, in large part, is due to the delicate relationship that exists between neurons in the central nervous system (CNS) and peripheral nervous system (PNS), and the resident immune cells that aid in homeostasis and immune surveillance within a tissue. Classically, the inner ear was thought to be immune privileged due to the presence of a blood-labyrinth barrier. However, it is now well-established that both vestibular and auditory end organs in the inner ear contain a resident (local) population of macrophages which are the phagocytic cells of the innate-immune system. Upon cochlear sterile injury or infection, there is robust activation of these resident macrophages and a predominant increase in the numbers of macrophages as well as other types of leukocytes. Despite this, the source, nature, fate, and functions of these immune cells during cochlear physiology and pathology remains unclear. Migration of local macrophages and infiltration of bone-marrow-derived peripheral blood macrophages into the damaged cochlea occur through various signaling cascades, mediated by the release of specific chemical signals from damaged sensory and non-sensory cells of the cochlea. One such signaling pathway is CX3CL1-CX3CR1, or fractalkine (FKN) signaling, a direct line of communication between macrophages and sensory inner hair cells (IHCs) and spiral ganglion neurons (SGNs) of the cochlea. Despite the known importance of this neuron-immune axis in CNS function and pathology, until recently it was not clear whether this signaling axis played a role in macrophage chemotaxis and SGN survival following cochlear injury. In this review, we will explore the importance of innate immunity in neurodegenerative disease development, specifically focusing on the regulation of the CX3CL1-CX3CR1 axis, and present evidence for a role of FKN signaling in cochlear neuroprotection.
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Affiliation(s)
- Andrew Rigel Stothert
- Department of Biomedical Sciences, School of Medicine, Creighton University, Omaha, NE, United States
| | - Tejbeer Kaur
- Department of Biomedical Sciences, School of Medicine, Creighton University, Omaha, NE, United States
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19
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Wu CH, Lu CW, Hsu TH, Wu WJ, Wang SE. Neurotoxicity of fipronil affects sensory and motor systems in zebrafish. PESTICIDE BIOCHEMISTRY AND PHYSIOLOGY 2021; 177:104896. [PMID: 34301358 DOI: 10.1016/j.pestbp.2021.104896] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/24/2020] [Revised: 05/17/2021] [Accepted: 06/02/2021] [Indexed: 06/13/2023]
Abstract
Fipronil is a phenylpyrazole insecticide that may selectively inhibit gamma-aminobutyric acid receptors in insects. Although fipronil is the most widely used insecticide in aquatic environments, few studies have evaluated its neurotoxicity for the sensory and motor systems of aquatic vertebrates. We assessed the effects of acute fipronil exposure on the survival rate, number of hair cells of lateral lines, and neurotoxicity for zebrafish (Danio rerio). In addition, heat maps and the speed and distance of the swimming trajectory were compared between zebrafish subjected to the sham and fipronil treatments. Western blotting and immunohistochemistry were conducted separately to compare expressions of oxidative stress, inflammation, apoptosis, and neurotoxicity related proteins in the brain tissue between adult zebrafish with sham and fipronil treatments. Our results indicated that the survival rates and the speed and distance of the swimming trajectory significantly decreased for adult zebrafish exposed to fipronil. The results also suggested that the number of hair cells of lateral lines significantly reduced for zebrafish embryos exposed to fipronil. In histopathology and Western blotting tests, substantial oxidative stress, inflammation, and apoptosis were observed in the brain tissue of adult zebrafish exposed to fipronil. Our results revealed that fipronil toxicity may impair sensory and motor systems in zebrafish because of damage to lateral hair cells and brain tissue through oxidative stress, inflammation, and apoptosis, which in turn result in a significantly reduced survival rate and impaired locomotion. The behavioral responses of zebrafish exposed to fipronil toxicity should be determined for better understanding the reliability of behavioral biomarkers in the risk assessment of environmental toxicology.
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Affiliation(s)
- Chung-Hsin Wu
- School of Life Science, National Taiwan Normal University, Taipei, Taiwan.
| | - Chen-Wen Lu
- School of Life Science, National Taiwan Normal University, Taipei, Taiwan
| | - Tai-Hsuan Hsu
- School of Life Science, National Taiwan Normal University, Taipei, Taiwan
| | - Wen-Jhen Wu
- School of Life Science, National Taiwan Normal University, Taipei, Taiwan
| | - Sheue-Er Wang
- Pathologist, Pathological Department, Saint Paul's Hospital, Taoyuan, Taiwa.
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20
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Sabbagh S, Amiri M, Khorramizadeh M, Iranpourmobarake Z, Nickbakht M. Neonatal Hearing Screening: Prevalence of Unilateral and Bilateral Hearing Loss and Associated Risk Factors. Cureus 2021; 13:e15947. [PMID: 34336445 PMCID: PMC8313994 DOI: 10.7759/cureus.15947] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/26/2021] [Indexed: 11/05/2022] Open
Abstract
INTRODUCTION Newborn hearing screening is essential for early identification of hearing loss to decrease the adverse effects of hearing loss. The objective of this study was to determine the prevalence of hearing loss and risk factors of congenital hearing loss in newborns. METHODS In this analytical case-control study, a hearing screening test was performed for all newborns aged 3-14 days. RESULTS Of 5,500 newborns evaluated, 24 newborns had hearing loss. The prevalence of hearing loss was 4.36 per 1,000. Of 24 hearing-impaired newborns, 15 had bilateral hearing loss (BHL) (62.5%) and nine had unilateral hearing loss (UHL) (37.5%). Among the neonates with hearing loss, the prevalence of hearing loss was higher (77.8%) in the right ear. The main risk factors identified in this study were low gestational age (P=0.001), hospitalization in the neonatal intensive care unit (NICU) (P=0.008), exposure to ototoxic drugs (P=0.001), gestational diabetes P=0.01), craniofacial anomalies (P=0.01), convulsion (P=0.03), consanguineous marriage of parents (P=0.001), low birth weight (P=0.01), and hyperbilirubinemia (P=0.001). CONCLUSION The prevalence of hearing loss was higher in the right ear than in the left ear. NICU stay, use of ototoxic drugs, low gestational age (<35 weeks), gestational diabetes, craniofacial anomalies, convulsion, consanguineous marriage of parents, low birth weight, and hyperbilirubinemia were significant risk factors for congenital hearing loss in studied newborns.
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Affiliation(s)
- Susan Sabbagh
- Department of Medical Anatomy, School of Medicine, Dezful University of Medical Sciences, Dezful, IRN
| | - Marzieh Amiri
- Musculoskeletal Rehabilitation Research Center, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, IRN.,Department of Audiology, School of Rehabilitation Sciences, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, IRN
| | - Maryam Khorramizadeh
- Department of Medical Physics, School of Medicine, Dezful University of Medical Sciences, Dezful, IRN
| | - Zahra Iranpourmobarake
- Musculoskeletal Rehabilitation Research Center, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, IRN.,Department of Audiology, School of Rehabilitation Sciences, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, IRN
| | - Mansoureh Nickbakht
- Department of Speech Pathology, School of Health and Rehabilitation Sciences, University of Queensland, Brisbane, AUS
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21
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Chai Y, He W, Yang W, Hetrick AP, Gonzalez JG, Sargsyan L, Wu H, Jung TTK, Li H. Intratympanic Lipopolysaccharide Elevates Systemic Fluorescent Gentamicin Uptake in the Cochlea. Laryngoscope 2021; 131:E2573-E2582. [PMID: 33956344 PMCID: PMC8453712 DOI: 10.1002/lary.29610] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2020] [Revised: 04/09/2021] [Accepted: 04/26/2021] [Indexed: 12/20/2022]
Abstract
Objectives/Hypothesis Lipopolysaccharide (LPS), a key component of bacterial endotoxins, activates macrophages and triggers the release of inflammatory cytokines in mammalian tissues. Recent studies have shown that intratympanic injection of LPS simulates acute otitis media (AOM) and results in morphological and functional changes in the inner ear. Here we established an AOM mouse model with LPS to investigate the uptake of ototoxic gentamicin in the inner ear, and elucidated the underlying mechanism by focusing on cochlear inflammation as a result of AOM. Study Design Preclinical rodent animal model. Methods Fluorescently tagged gentamicin (GTTR) was systemically administered to mice with AOM. Iba1‐positive macrophage morphology and inner ear cytokine profile were evaluated by immunofluorescence technique and a mouse cytokine array kit, respectively. Results We observed characteristic symptoms of AOM in the LPS‐treated ears with elevated hearing thresholds indicating a conductive hearing loss. More importantly, the LPS‐induced AOM activated cochlear inflammatory responses, manifested by macrophage infiltration, particularly in the organ of Corti and the spiral ligament, in addition to the up‐regulation of proinflammatory cytokines. Meanwhile, GTTR uptake in the stria vascularis and sensory hair cells from all the LPS‐treated ears was significantly enhanced at 24, 48, and 72‐hour post‐treatment, as the most prominent enhancement was observed in the 48‐hour group. Conclusion In summary, this study suggests that the pathological cochlea is more susceptible to ototoxic drugs, including aminoglycosides, and justified the clinical concern of aminoglycoside ototoxicity in the AOM treatment. Laryngoscope, 131:E2573–E2582, 2021
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Affiliation(s)
- Yongchuan Chai
- Research Service, VA Loma Linda Healthcare System, Loma Linda, California, U.S.A.,Department of Otolaryngology Head and Neck Surgery, Shanghai Ninth People's Hospital Affiliated Shanghai Jiaotong University School of Medicine, Shanghai, China.,Ear Institute, Shanghai Jiaotong University School of Medicine, Shanghai, China.,Department of Otolaryngology Head and Neck Surgery, Loma Linda University Health, Loma Linda, California, U.S.A
| | - Weiwei He
- Research Service, VA Loma Linda Healthcare System, Loma Linda, California, U.S.A.,Department of Otolaryngology Head and Neck Surgery, Shanghai Ninth People's Hospital Affiliated Shanghai Jiaotong University School of Medicine, Shanghai, China.,Ear Institute, Shanghai Jiaotong University School of Medicine, Shanghai, China.,Department of Otolaryngology Head and Neck Surgery, Loma Linda University Health, Loma Linda, California, U.S.A
| | - Weiqiang Yang
- Research Service, VA Loma Linda Healthcare System, Loma Linda, California, U.S.A.,Department of Otolaryngology Head and Neck Surgery, Loma Linda University Health, Loma Linda, California, U.S.A
| | - Alisa P Hetrick
- Research Service, VA Loma Linda Healthcare System, Loma Linda, California, U.S.A
| | - Jessica G Gonzalez
- Research Service, VA Loma Linda Healthcare System, Loma Linda, California, U.S.A
| | - Liana Sargsyan
- Research Service, VA Loma Linda Healthcare System, Loma Linda, California, U.S.A
| | - Hao Wu
- Department of Otolaryngology Head and Neck Surgery, Shanghai Ninth People's Hospital Affiliated Shanghai Jiaotong University School of Medicine, Shanghai, China.,Ear Institute, Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Timothy T K Jung
- Research Service, VA Loma Linda Healthcare System, Loma Linda, California, U.S.A.,Department of Otolaryngology Head and Neck Surgery, Loma Linda University Health, Loma Linda, California, U.S.A
| | - Hongzhe Li
- Research Service, VA Loma Linda Healthcare System, Loma Linda, California, U.S.A.,Department of Otolaryngology Head and Neck Surgery, Loma Linda University Health, Loma Linda, California, U.S.A
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22
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Babolmorad G, Latif A, Domingo IK, Pollock NM, Delyea C, Rieger AM, Allison WT, Bhavsar AP. Toll-like receptor 4 is activated by platinum and contributes to cisplatin-induced ototoxicity. EMBO Rep 2021; 22:e51280. [PMID: 33733573 PMCID: PMC8097357 DOI: 10.15252/embr.202051280] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2020] [Revised: 02/18/2021] [Accepted: 02/23/2021] [Indexed: 12/12/2022] Open
Abstract
Toll-like receptor 4 (TLR4) recognizes bacterial lipopolysaccharide (LPS) and can also be activated by some Group 9/10 transition metals, which is believed to mediate immune hypersensitivity reactions. In this work, we test whether TLR4 can be activated by the Group 10 metal platinum and the platinum-based chemotherapeutic cisplatin. Cisplatin is invaluable in childhood cancer treatment but its use is limited due to a permanent hearing loss (cisplatin-induced ototoxicity, CIO) adverse effect. We demonstrate that platinum and cisplatin activate pathways downstream of TLR4 to a similar extent as the known TLR4 agonists LPS and nickel. We further show that TLR4 is required for cisplatin-induced inflammatory, oxidative, and cell death responses in hair cells in vitro and for hair cell damage in vivo. Finally, we identify a TLR4 small molecule inhibitor able to curtail cisplatin toxicity in vitro. Thus, our findings indicate that TLR4 is a promising therapeutic target to mitigate CIO.
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Affiliation(s)
- Ghazal Babolmorad
- Department of Medical Microbiology and ImmunologyFaculty of Medicine & DentistryUniversity of AlbertaEdmontonABCanada
| | - Asna Latif
- Department of Medical Microbiology and ImmunologyFaculty of Medicine & DentistryUniversity of AlbertaEdmontonABCanada
| | - Ivan K Domingo
- Department of Medical Microbiology and ImmunologyFaculty of Medicine & DentistryUniversity of AlbertaEdmontonABCanada
| | - Niall M Pollock
- Department of Biological SciencesFaculty of ScienceUniversity of AlbertaEdmontonABCanada
| | - Cole Delyea
- Department of Medical Microbiology and ImmunologyFaculty of Medicine & DentistryUniversity of AlbertaEdmontonABCanada
| | - Aja M Rieger
- Department of Medical Microbiology and ImmunologyFaculty of Medicine & DentistryUniversity of AlbertaEdmontonABCanada
| | - W Ted Allison
- Department of Biological SciencesFaculty of ScienceUniversity of AlbertaEdmontonABCanada
- Department of Medical GeneticsFaculty of Medicine & DentistryUniversity of AlbertaEdmontonABCanada
| | - Amit P Bhavsar
- Department of Medical Microbiology and ImmunologyFaculty of Medicine & DentistryUniversity of AlbertaEdmontonABCanada
- Department of Medical GeneticsFaculty of Medicine & DentistryUniversity of AlbertaEdmontonABCanada
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23
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Perin P, Marino F, Varela-Nieto I, Szczepek AJ. Editorial: Neuroimmunology of the Inner Ear. Front Neurol 2021; 12:635359. [PMID: 33633679 PMCID: PMC7899967 DOI: 10.3389/fneur.2021.635359] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Accepted: 01/07/2021] [Indexed: 12/20/2022] Open
Affiliation(s)
- Paola Perin
- Department of Brain and Behavioural Sciences, University of Pavia, Pavia, Italy
| | - Franca Marino
- Center of Research in Medical Pharmacology University of Insubria, Varese, Italy
| | - Isabel Varela-Nieto
- Institute for Biomedical Research "Alberto Sols" (IIBM), Spanish National Research Council-Autonomous University of Madrid (CSIC-UAM), Madrid, Spain.,Rare Diseases Networking Biomedical Research Centre, Centro de Investigación Biomédica en Red, Carlos III Institute of Health, Madrid, Spain.,La Paz Hospital Institute for Health Research (IdiPAZ), Madrid, Spain
| | - Agnieszka J Szczepek
- Department of Otorhinolaryngology, Head and Neck Surgery, Charité-Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany.,Faculty of Medicine and Health Sciences, University of Zielona Gora, Zielona Gora, Poland
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24
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Xu K, Chen S, Xie L, Qiu Y, Bai X, Liu XZ, Zhang HM, Wang XH, Jin Y, Sun Y, Kong WJ. Local Macrophage-Related Immune Response Is Involved in Cochlear Epithelial Damage in Distinct Gjb2-Related Hereditary Deafness Models. Front Cell Dev Biol 2021; 8:597769. [PMID: 33505961 PMCID: PMC7829512 DOI: 10.3389/fcell.2020.597769] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2020] [Accepted: 12/07/2020] [Indexed: 12/31/2022] Open
Abstract
The macrophage-related immune response is an important component of the cochlear response to different exogenous stresses, including noise, ototoxic antibiotics, toxins, or viral infection. However, the role of the immune response in hereditary deafness caused by genetic mutations is rarely explored. GJB2, encoding connexin 26 (Cx26), is the most common deafness gene of hereditary deafness. In this study, two distinct Cx26-null mouse models were established to investigate the types and underlying mechanisms of immune responses. In a systemic Cx26-null model, macrophage recruitment was observed, associated with extensive cell degeneration of the cochlear epithelium. In a targeted-cell Cx26-null model, knockout of Cx26 was restricted to specific supporting cells (SCs), which led to preferential loss of local outer hair cells (OHCs). This local OHC loss can also induce a macrophage-related immune response. Common inflammatory factors, including TNF-α, IL-1β, Icam-1, Mif, Cx3cr1, Tlr4, Ccl2, and Ccr2, did not change significantly, while mRNA of Cx3cl1 was upregulated. Quantitative immunofluorescence showed that the protein expression of CX3CL1 in Deiters cells, a type of SC coupled with OHCs, increased significantly after OHC death. OHC loss caused the secondary death of spiral ganglion neurons (SGNs), while the remaining SGNs expressed high levels of CX3CL1 with infiltrated macrophages. Taken together, our results indicate that CX3CL1 signaling regulates macrophage recruitment and that enhancement of macrophage antigen-presenting function is associated with cell degeneration in Cx26-null mice.
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Affiliation(s)
- Kai Xu
- Department of Otorhinolaryngology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Sen Chen
- Department of Otorhinolaryngology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Le Xie
- Department of Otorhinolaryngology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Yue Qiu
- Department of Otorhinolaryngology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Xue Bai
- Department of Otorhinolaryngology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Xiao-Zhou Liu
- Department of Otorhinolaryngology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Hui-Min Zhang
- Department of Otorhinolaryngology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Xiao-Hui Wang
- Department of Otorhinolaryngology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Yuan Jin
- Department of Otorhinolaryngology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Yu Sun
- Department of Otorhinolaryngology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Wei-Jia Kong
- Department of Otorhinolaryngology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.,Tongji Medical College, Institute of Otorhinolaryngology, Huazhong University of Science and Technology, Wuhan, China
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25
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Ding Y, Meng W, Kong W, He Z, Chai R. The Role of FoxG1 in the Inner Ear. Front Cell Dev Biol 2020; 8:614954. [PMID: 33344461 PMCID: PMC7744801 DOI: 10.3389/fcell.2020.614954] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2020] [Accepted: 11/18/2020] [Indexed: 12/12/2022] Open
Abstract
Sensorineural deafness is mainly caused by damage to the tissues of the inner ear, and hearing impairment has become an increasingly serious global health problem. When the inner ear is abnormally developed or is damaged by inflammation, ototoxic drugs, or blood supply disorders, auditory signal transmission is inhibited resulting in hearing loss. Forkhead box G1 (FoxG1) is an important nuclear transcriptional regulator, which is related to the differentiation, proliferation, development, and survival of cells in the brain, telencephalon, inner ear, and other tissues. Previous studies have shown that when FoxG1 is abnormally expressed, the development and function of inner ear hair cells is impaired. This review discusses the role and regulatory mechanism of FoxG1 in inner ear tissue from various aspects – such as the effect on inner ear development, the maintenance of inner ear structure and function, and its role in the inner ear when subjected to various stimulations or injuries – in order to explain the potential significance of FoxG1 as a new target for the treatment of hearing loss.
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Affiliation(s)
- Yanyan Ding
- Department of Otorhinolaryngology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Wei Meng
- Department of Otolaryngology Head and Neck, Nanjing Tongren Hospital, School of Medicine, Southeast University, Nanjing, China
| | - Weijia Kong
- Department of Otorhinolaryngology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Zuhong He
- Department of Otorhinolaryngology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Renjie Chai
- State Key Laboratory of Bioelectronics, School of Life Sciences and Technology, Jiangsu Province High-Tech Key Laboratory for Bio-Medical Research, Southeast University, Nanjing, China.,Co-Innovation Center of Neuroregeneration, Nantong University, Nantong, China.,Institute of Stem Cell and Regeneration, Chinese Academy of Sciences, Beijing, China.,Beijing Key Laboratory of Neural Regeneration and Repair, Capital Medical University, Beijing, China
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26
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Yim JJ, Singh SP, Xia A, Kashfi-Sadabad R, Tholen M, Huland DM, Zarabanda D, Cao Z, Solis-Pazmino P, Bogyo M, Valdez TA. Short-Wave Infrared Fluorescence Chemical Sensor for Detection of Otitis Media. ACS Sens 2020; 5:3411-3419. [PMID: 33175516 DOI: 10.1021/acssensors.0c01272] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Otitis media (OM) or middle ear infection is one of the most common diseases in young children around the world. The diagnosis of OM is currently performed using an otoscope to detect middle ear fluid and inflammatory changes manifested in the tympanic membrane. However, conventional otoscopy cannot visualize across the tympanic membrane or sample middle ear fluid. This can lead to low diagnostic certainty and overdiagnoses of OM. To improve the diagnosis of OM, we have developed a short-wave infrared (SWIR) otoscope in combination with a protease-cleavable biosensor, 6QC-ICG, which can facilitate the detection of inflammatory proteases in the middle ear with an increase in contrast. 6QC-ICG is a fluorescently quenched probe, which is activated in the presence of cysteine cathepsin proteases that are up-regulated in inflammatory immune cells. Using a preclinical model and custom-built SWIR otomicroscope in this proof-of-concept study, we successfully demonstrated the feasibility of robustly distinguishing inflamed ears from controls (p = 0.0006). The inflamed ears showed an overall signal-to-background ratio of 2.0 with a mean fluorescence of 81 ± 17 AU, while the control ear exhibited a mean fluorescence of 41 ± 11 AU. We envision that these fluorescently quenched probes in conjunction with SWIR imaging tools have the potential to be used as an alternate/adjunct tool for objective diagnosis of OM.
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Affiliation(s)
- Joshua J. Yim
- Department of Chemical and Systems Biology, Stanford University School of Medicine, Stanford, California 94305, United States
| | - Surya Pratap Singh
- Department of Otolaryngology−Head & Neck Surgery Divisions, Stanford University School of Medicine, Stanford, California 94305, United States
- Department of Biosciences and Bioengineering, Indian Institute of Technology Dharwad, Dharwad, Karnataka 580011, India
| | - Anping Xia
- Department of Otolaryngology−Head & Neck Surgery Divisions, Stanford University School of Medicine, Stanford, California 94305, United States
| | - Raana Kashfi-Sadabad
- Department of Otolaryngology−Head & Neck Surgery Divisions, Stanford University School of Medicine, Stanford, California 94305, United States
| | - Martina Tholen
- Department of Pathology, Stanford University School of Medicine, Stanford, California 94305, United States
| | - David M. Huland
- Molecular Imaging Program at Stanford, Department of Radiology, Stanford University School of Medicine, Stanford, California 94305, United States
| | - David Zarabanda
- Department of Otolaryngology−Head & Neck Surgery Divisions, Stanford University School of Medicine, Stanford, California 94305, United States
| | - Zhixin Cao
- Department of Otolaryngology−Head & Neck Surgery Divisions, Stanford University School of Medicine, Stanford, California 94305, United States
- Department of Pathology, Shandong Provincial Hospital Affiliated to Shandong First Medical University, Jinan, Shandong 250021, China
| | - Paola Solis-Pazmino
- Department of Otolaryngology−Head & Neck Surgery Divisions, Stanford University School of Medicine, Stanford, California 94305, United States
| | - Matthew Bogyo
- Department of Chemical and Systems Biology, Stanford University School of Medicine, Stanford, California 94305, United States
- Department of Pathology, Stanford University School of Medicine, Stanford, California 94305, United States
- Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, California 94305, United States
| | - Tulio A. Valdez
- Department of Otolaryngology−Head & Neck Surgery Divisions, Stanford University School of Medicine, Stanford, California 94305, United States
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27
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Longenecker RJ, Gu R, Homan J, Kil J. A Novel Mouse Model of Aminoglycoside-Induced Hyperacusis and Tinnitus. Front Neurosci 2020; 14:561185. [PMID: 33041759 PMCID: PMC7530258 DOI: 10.3389/fnins.2020.561185] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2020] [Accepted: 08/20/2020] [Indexed: 11/13/2022] Open
Abstract
Aminoglycosides (AG) such as amikacin are commonly used in cystic fibrosis patients with opportunistic pulmonary infections including multi-drug resistant mycobacterium tuberculous and non-tuberculous mycobacterium. Unfortunately, this class of drugs is known to cause peripheral damage to the cochlea leading to hearing loss that can fluctuate and become permanent over time or multiple exposures. However, whether amikacin can lead to central auditory dysfunction like hyperacusis (increased sensitivity to sound) or tinnitus (perception of sound in the absence of acoustic stimulation) is not well-described in the literature. Thus, an animal model needs to be developed that documents these side effects in order to develop therapeutic solutions to reduce AG-induced auditory dysfunction. Here we present pioneer work in mice which demonstrates that amikacin can lead to fluctuating behavioral evidence of hyperacusis and tinnitus as assessed by the acoustic startle reflex. Additionally, electrophysiological assessments of hearing via auditory brainstem response demonstrate increased central activity in the auditory brainstem. These data together suggest that peripheral AG-induced dysfunction can lead to central hyperactivity and possible behavioral manifestations of hyperacusis and tinnitus. Importantly, we demonstrate that ebselen, a novel investigational drug that acts as both an antioxidant and anti-inflammatory, can mitigate AG-induced hyperacusis.
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Affiliation(s)
| | - Rende Gu
- Sound Pharmaceuticals, Inc., Seattle, WA, United States
| | | | - Jonathan Kil
- Sound Pharmaceuticals, Inc., Seattle, WA, United States
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28
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Toll-like Receptor 4 Signaling and Downstream Neutrophilic Inflammation Mediate Endotoxemia-Enhanced Blood-Labyrinth Barrier Trafficking. Otol Neurotol 2020; 41:123-132. [PMID: 31568132 DOI: 10.1097/mao.0000000000002447] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
HYPOTHESIS Both toll-like receptor 4 (TLR4) and downstream neutrophil activity are required for endotoxemia-enhanced blood-labyrinth barrier (BLB) trafficking. BACKGROUND Aminoglycoside and cisplatin are valuable clinical therapies; however, these drugs often cause life-long hearing loss. Endotoxemia enhances the ototoxicity of aminoglycosides and cisplatin in a TLR4 dependent mechanism for which downstream proinflammatory signaling orchestrates effector immune cells including neutrophils. Neutrophil-mediated vascular injury (NMVI) can enhance molecular trafficking across endothelial barriers and may contribute to endotoxemia-enhanced drug-induced ototoxicity. METHODS Lipopolysaccharide (LPS) hypo-responsive TLR4-KO mice and congenitally neutropenic granulocyte colony-stimulating factor (GCSF) GCSF-KO mice were studied to investigate the relative contributions of TLR4 signaling and downstream neutrophil activity to endotoxemia-enhanced BLB trafficking. C57Bl/6 wild-type mice were used as a positive control. Mice were treated with LPS and 24 hours later cochleae were analyzed for gene transcription of innate inflammatory cytokine/chemokine signaling molecules, neutrophil recruitment, and vascular trafficking of the paracellular tracer biocytin-TMR. RESULTS Cochlear transcription of innate proinflammatory cytokines/chemokines was increased in endotoxemic C57Bl/6 and GCSF-KO, but not in TLR4-KO mice. More neutrophils were recruited to endotoxemic C57Bl/6 cochleae compared with both TLR4 and GCSF-KO cochleae. Endotoxemia enhanced BLB trafficking of biocytin-TMR in endotoxemic C57Bl/6 cochleae and this was attenuated in both TLR4 and GCSF-KO mice. CONCLUSION Together these results suggest that TLR4-mediated innate immunity cytokine/chemokine signaling alone is not sufficient for endotoxemia-enhanced trafficking of biocytin-TMR and that downstream neutrophil activity is required to enhance BLB trafficking. Clinically, targeting neutrophilic inflammation could protect hearing during aminoglycoside, cisplatin, or other ototoxic drug therapies.
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29
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Zhang C, Frye MD, Sun W, Sharma A, Manohar S, Salvi R, Hu BH. New insights on repeated acoustic injury: Augmentation of cochlear susceptibility and inflammatory reaction resultant of prior acoustic injury. Hear Res 2020; 393:107996. [PMID: 32534268 DOI: 10.1016/j.heares.2020.107996] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/22/2019] [Revised: 04/29/2020] [Accepted: 05/12/2020] [Indexed: 12/20/2022]
Abstract
In industrial and military settings, individuals who suffer from one episode of acoustic trauma are likely to sustain another episode of acoustic stress, creating an opportunity for a potential interaction between the two stress conditions. We previously demonstrated that acoustic overstimulation perturbs the cochlear immune environment. However, how the cochlear immune system responds to repeated acoustic overstimulation is unknown. Here, we used a mouse model to investigate the cochlear immune response to repeated stress. We reveal that exposure to an intense noise at 120 dB SPL for 1 h activates the cochlear immune response in a time-dependent fashion with substantial expansion and activation of the macrophage population in the cochlea at 2-days post-exposure. At 20-days post-exposure, the number and pro-inflammatory phenotypes of cochlear macrophages have significantly subsided, but have yet to return to homeostatic levels. Monocytes with anti-inflammatory phenotypes are recruited into the cochlea. With the presence of this residual immune activation, a second exposure to the same noise provokes an exaggerated inflammatory response as evidenced by exacerbated maturation of macrophages. Furthermore, the second noise causes greater sensory cell pathogenesis. Unlike the first noise-induced damage that occurs mainly between 0 and 2 days post-exposure, the second noise-induced damage occurs more frequently between 2 and 20 days post-exposure, the period when secondary damage takes place. These observations suggest that repeated acoustic overstimulation exacerbates cochlear inflammation and secondary sensory cell pathogenesis. Together, our results suggest that the cochlear immune system plays an important role in modulating cochlear responses to repeated acoustic stress.
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Affiliation(s)
- Celia Zhang
- Center for Hearing and Deafness, University at Buffalo, 137 Cary Hall, 3435 Main Street, Buffalo, NY, 14214, USA.
| | - Mitchell D Frye
- Center for Hearing and Deafness, University at Buffalo, 137 Cary Hall, 3435 Main Street, Buffalo, NY, 14214, USA.
| | - Wei Sun
- Center for Hearing and Deafness, University at Buffalo, 137 Cary Hall, 3435 Main Street, Buffalo, NY, 14214, USA.
| | - Ashu Sharma
- Department of Oral Biology, University at Buffalo, School of Dental Medicine, University of Buffalo, The State University of New York, Buffalo, NY, USA, 14214.
| | - Senthilvelan Manohar
- Center for Hearing and Deafness, University at Buffalo, 137 Cary Hall, 3435 Main Street, Buffalo, NY, 14214, USA.
| | - Richard Salvi
- Center for Hearing and Deafness, University at Buffalo, 137 Cary Hall, 3435 Main Street, Buffalo, NY, 14214, USA.
| | - Bo Hua Hu
- Center for Hearing and Deafness, University at Buffalo, 137 Cary Hall, 3435 Main Street, Buffalo, NY, 14214, USA.
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30
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Peek NFAW, Nell MJ, Brand R, Jansen-Werkhoven T, van Hoogdalem EJ, Verrijk R, Vonk MJ, Wafelman AR, Valentijn ARPM, Frijns JHM, Hiemstra PS, Drijfhout JW, Nibbering PH, Grote JJ. Ototopical drops containing a novel antibacterial synthetic peptide: Safety and efficacy in adults with chronic suppurative otitis media. PLoS One 2020; 15:e0231573. [PMID: 32287316 PMCID: PMC7156094 DOI: 10.1371/journal.pone.0231573] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2018] [Accepted: 03/25/2020] [Indexed: 11/18/2022] Open
Abstract
OBJECTIVE Chronic suppurative otitis media (CSOM) is a chronic infectious disease with worldwide prevalence that causes hearing loss and decreased quality of life. As current (antibiotic) treatments often unsuccessful and antibiotic resistance is emerging, alternative agents and/or strategies are urgently needed. We considered the synthetic antimicrobial and anti-biofilm peptide P60.4Ac to be an interesting candidate because it also displays anti-inflammatory activities including lipopolysaccharide-neutralizing activity. The aim of the present study was to investigate the safety and efficacy of ototopical drops containing P60.4Ac in adults with CSOM without cholesteatoma. METHODS We conducted a range-finding study in 16 subjects followed by a randomized, double blinded, placebo-controlled, multicentre phase IIa study in 34 subjects. P60.4Ac-containing ototopical drops or placebo drops were applied twice a day for 2 weeks and adverse events (AEs) and medication use were recorded. Laboratory tests, swabs from the middle ear and throat for bacterial cultures, and audiometry were performed at intervals up to 10 weeks after therapy. Response to treatment was assessed by blinded symptom scoring on otoscopy. RESULTS Application of P60.4Ac-containing ototopical drops (0.25-2.0 mg of peptide/ml) in the ear canal of patients suffering from CSOM was found to be safe and well-tolerated. The optimal dose (0.5 mg of peptide/ml) was selected for the subsequent phase IIa study. Safety evaluation revealed only a few AEs that were unlikely related to study treatment and all, except one, were of mild to moderate intensity. In addition to this excellent safety profile, P60.4Ac ototopical drops resulted in a treatment success in 47% of cases versus 6% in the placebo group. CONCLUSION The efficacy/safety balance assessed in the present study provides a compelling justification for continued clinical development of P60.4Ac in therapy-resistant CSOM.
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Affiliation(s)
- Nanno F. A. W. Peek
- Department of Ear Nose and Throat, Leiden University Medical Centre (LUMC), Leiden, The Netherlands
| | - Marja J. Nell
- Octoplus Technologies BV/Dr Reddy’s research and development BV, Leiden, The Netherlands
| | - Ronald Brand
- Department of Biomedical Data Sciences, Leiden University Medical Centre, Leiden, The Netherlands
| | - Thekla Jansen-Werkhoven
- Department of Biomedical Data Sciences, Leiden University Medical Centre, Leiden, The Netherlands
| | - Ewoud J. van Hoogdalem
- Octoplus Technologies BV/Dr Reddy’s research and development BV, Leiden, The Netherlands
| | - Ruud Verrijk
- Octoplus Technologies BV/Dr Reddy’s research and development BV, Leiden, The Netherlands
| | - Marcel J. Vonk
- Department of Pulmonology, Leiden University Medical Centre, Leiden, The Netherlands
| | - Amon R. Wafelman
- Clinical Pharmacology and Toxicology, Leiden University Medical Centre, Leiden, The Netherlands
| | - A. Rob P. M. Valentijn
- Clinical Pharmacology and Toxicology, Leiden University Medical Centre, Leiden, The Netherlands
| | - Johan H. M. Frijns
- Department of Ear Nose and Throat, Leiden University Medical Centre (LUMC), Leiden, The Netherlands
| | - Pieter S. Hiemstra
- Department of Pulmonology, Leiden University Medical Centre, Leiden, The Netherlands
| | - Jan W. Drijfhout
- Immunohematology and Blood Transfusion, Leiden University Medical Centre, Leiden, The Netherlands
| | - Peter H. Nibbering
- Department of Infectious Diseases, Leiden University Medical Centre, Leiden, The Netherlands
| | - Jan J. Grote
- Department of Ear Nose and Throat, Leiden University Medical Centre (LUMC), Leiden, The Netherlands
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31
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Low WK, Teng SW, Tan MGK. Synergistic Ototoxicity of Gentamicin and Low-Dose Irradiation: Molecular Basis and Clinical Significance. Audiol Neurootol 2019; 25:111-119. [PMID: 31838466 DOI: 10.1159/000503133] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2019] [Accepted: 09/03/2019] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Inner ear structures may be included in the radiation fields when irradiation is used to treat patients with head and neck cancers. These patients may also have concurrent infections that require gentamicin treatment. Radiation and gentamicin are both potentially ototoxic, and their combined use has been shown to result in synergistic ototoxicity in animals. OBJECTIVE We aimed to confirm the synergistic ototoxicity of combined gentamicin and low-dose irradiation treatment and identify the underlying molecular mechanisms using an in vitro model. METHOD We compared the ototoxic effects of gentamicin, low-dose irradiation, and their combination in the OC-k3 mouse cochlear cell line using cell viability assay, live/dead stain, apoptosis detection assay, oxidative stress detection, and studied the molecular mechanisms involved using immunoblot analysis. RESULTS Combined treatment led to prolonged oxidative stress, reduced cell viability, and synergistic apoptosis. Gentamicin induced the concurrent accumulation of LC3b-II and SQSTM1/p62, suggesting an impairment of autophagic flux. Low-dose irradiation induced transient p53 phosphorylation and persistent Akt phosphorylation in response to DNA damage. In combined treatment, gentamicin attenuated irradiation-induced Akt activation. CONCLUSIONS Besides increased oxidative stress, synergistic apoptosis observed in combined treatment could be attributed to gentamicin-induced perturbation of autophagic flux and attenuation of Akt phosphorylation, which led to an impairment of radiation-induced DNA repair response.
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Affiliation(s)
- Wong Kein Low
- Department of Otolaryngology, Singapore General Hospital, Singapore, Singapore, .,Duke-NUS Graduate Medical School, Singapore, Singapore, .,Novena Ent-Head and Neck Surgery Specialist Centre, Mount Elizabeth Novena Medical Centre, Singapore, Singapore,
| | - Siaw Wei Teng
- Department of Otolaryngology, Singapore General Hospital, Singapore, Singapore
| | - Michelle G K Tan
- Departments of Clinical Translational Research, Singapore General Hospital, Singapore, Singapore
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32
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The nuclear transcription factor FoxG1 affects the sensitivity of mimetic aging hair cells to inflammation by regulating autophagy pathways. Redox Biol 2019; 28:101364. [PMID: 31731101 PMCID: PMC6920089 DOI: 10.1016/j.redox.2019.101364] [Citation(s) in RCA: 117] [Impact Index Per Article: 23.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2019] [Revised: 10/22/2019] [Accepted: 10/27/2019] [Indexed: 12/18/2022] Open
Abstract
Inflammation is a self-defense response to protect individuals from infection and tissue damage, but excessive or persistent inflammation can have adverse effects on cell survival. Many individuals become especially susceptible to chronic-inflammation-induced sensorineural hearing loss as they age, but the intrinsic molecular mechanism behind aging individuals' increased risk of hearing loss remains unclear. FoxG1 (forkhead box transcription factor G1) is a key transcription factor that plays important roles in hair cell survival through the regulation of mitochondrial function, but how the function of FoxG1 changes during aging and under inflammatory conditions is unknown. In this study, we first found that FoxG1 expression and autophagy both increased gradually in the low concentration lipopolysaccharide (LPS)-induced inflammation model, while after high concentration of LPS treatment both FoxG1 expression and autophagy levels decreased as the concentration of LPS increased. We then used siRNA to downregulate Foxg1 expression in hair cell-like OC-1 cells and found that cell death and apoptosis were significantly increased after LPS injury. Furthermore, we used d-galactose (D-gal) to create an aging model with hair cell-like OC-1 cells and cochlear explant cultures in vitro and found that the expression of Foxg1 and the level of autophagy were both decreased after D-gal and LPS co-treatment. Lastly, we knocked down the expression of Foxg1 under aged inflammation conditions and found increased numbers of dead and apoptotic cells. Together these results suggest that FoxG1 affects the sensitivity of mimetic aging hair cells to inflammation by regulating autophagy pathways.
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33
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Singh SP, Xia A, Tusty M, Victorovich Malkovskiy A, Easwaran M, Zarabanda D, Valdez TA. Identification of early inflammatory changes in the tympanic membrane with Raman spectroscopy. Analyst 2019; 144:6721-6728. [PMID: 31612878 DOI: 10.1039/c9an01772k] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The tympanic membrane (TM) is a dynamic structure that separates the middle ear from the external auditory canal. It is also integral for the transmission of sound waves. In this study, we demonstrate the feasibility of using Raman spectroscopy to identify early chemical changes resulting from inflammation in the TM that can serve as an indicator of acute otitis media. Bacterial lipopolysaccharide (LPS) was injected trans-tympanicaly in a murine model. Presence of inflammatory response was assessed with binocular microscopy, confirmed with histopathology and immunofluorescence staining. Successful discrimination suggesting spectral differences among the control and LPS treated groups was achieved using principal component analysis. Raman imaging revealed major differences in collagen distribution and nucleic acid content. Image segmentation analysis on the trichrome stained tissue sections was performed to corroborate the Raman spectra. The spectral co-localization study suggests changes in the expression of collagen IV specific signals in LPS treated samples. The overall findings of the study support prospective application of RS in the diagnosis and therapeutic monitoring of otitis media.
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Affiliation(s)
- S P Singh
- Department of Otolaryngology and Head and Neck Surgery, School of Medicine, Stanford University, Palo Alto, CA 94305, USA.
| | - Anping Xia
- Department of Otolaryngology and Head and Neck Surgery, School of Medicine, Stanford University, Palo Alto, CA 94305, USA.
| | - Mahbuba Tusty
- Department of Otolaryngology and Head and Neck Surgery, School of Medicine, Stanford University, Palo Alto, CA 94305, USA.
| | | | - Meena Easwaran
- Department of Otolaryngology and Head and Neck Surgery, School of Medicine, Stanford University, Palo Alto, CA 94305, USA.
| | - David Zarabanda
- Department of Otolaryngology and Head and Neck Surgery, School of Medicine, Stanford University, Palo Alto, CA 94305, USA.
| | - Tulio A Valdez
- Department of Otolaryngology and Head and Neck Surgery, School of Medicine, Stanford University, Palo Alto, CA 94305, USA.
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34
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Chan YH, Liu TC, Liao CK, Cheng YF, Tsai CH, Lu YC, Hu CJ, Lin HJ, Lee YL, Wu CC, Hsu CJ. Consumption of betel quid contributes to sensorineural hearing impairment through arecoline-induced oxidative stress. Sci Rep 2019; 9:14554. [PMID: 31601870 PMCID: PMC6787045 DOI: 10.1038/s41598-019-49815-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2019] [Accepted: 08/22/2019] [Indexed: 11/09/2022] Open
Abstract
Betel quid is one of the most widely used psychoactive substances, and is consumed by approximately 10% of the world’s population. In addition to its carcinogenicity, betel quid has also been reported to affect many organs, including the brain, heart, lungs, gastrointestinal tract, and reproductive organs. As betel quid contains several neurotoxic ingredients, we hypothesize that it also possesses ototoxicity and may lead to sensorineural hearing impairment (SNHI). In this study, we investigated the contribution of betel quid consumption to SNHI in a large clinical cohort, and validated the pathogenetic mechanisms in ex vivo tissue explants. We enrolled a total of 2364 volunteers, and determined their audiologic results based on Z-scores converted from their original frequency-specific hearing thresholds. Using generalized linear regression, we identified a positive correlation between betel quid consumption and the Z-scores across different frequencies. Subsequently, we explored the toxicity of arecoline, the main neuroactive component of betel quid, on tissue explants from murine cochleae. Arecoline reduced cell activity in the explant cultures and induced apoptosis in the hair cells, probably through the effects of oxidative stress. These findings have expanded the potential hazards of betel quid to common neurological disorders, and provide insights into preventive strategies against SNHI caused by neurotoxic substances.
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Affiliation(s)
- Yen-Hui Chan
- Department of Otolaryngology, National Taiwan University Hospital, Taipei, Taiwan.,Department of Otolaryngology, Taichung Tzu Chi Hospital, Buddhist Tzu Chi Medical Foundation, Taichung, Taiwan
| | - Tien-Chen Liu
- Department of Otolaryngology, National Taiwan University Hospital, Taipei, Taiwan
| | - Chun-Kang Liao
- Department of Otolaryngology, National Taiwan University Hospital, Taipei, Taiwan
| | - Yen-Fu Cheng
- Department of Medical Research, Taipei Veterans General Hospital, Taipei, Taiwan.,Department of Otolaryngology-Head and Neck Surgery, Taipei Veterans General Hospital, Taipei, Taiwan.,School of Medicine, National Yang-Ming University, Taipei, Taiwan
| | - Ching-Hui Tsai
- Institute of Epidemiology and Preventive Medicine, College of Public Health, National Taiwan University, Taipei, Taiwan
| | - Ying-Chang Lu
- Department of Otolaryngology, National Taiwan University Hospital, Taipei, Taiwan
| | - Chin-Ju Hu
- Department of Otolaryngology, National Taiwan University Hospital, Taipei, Taiwan
| | - Hung-Ju Lin
- Health Management Center, National Taiwan University Hospital, Taipei, Taiwan
| | - Yungling Leo Lee
- Institute of Epidemiology and Preventive Medicine, College of Public Health, National Taiwan University, Taipei, Taiwan.,Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan
| | - Chen-Chi Wu
- Department of Otolaryngology, National Taiwan University Hospital, Taipei, Taiwan. .,Department of Medical Genetics, National Taiwan University Hospital, Taipei, Taiwan.
| | - Chuan-Jen Hsu
- Department of Otolaryngology, National Taiwan University Hospital, Taipei, Taiwan.,Department of Otolaryngology, Taichung Tzu Chi Hospital, Buddhist Tzu Chi Medical Foundation, Taichung, Taiwan
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35
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Sahley TL, Anderson DJ, Hammonds MD, Chandu K, Musiek FE. Evidence for a dynorphin-mediated inner ear immune/inflammatory response and glutamate-induced neural excitotoxicity: an updated analysis. J Neurophysiol 2019; 122:1421-1460. [DOI: 10.1152/jn.00595.2018] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Acoustic overstimulation (AOS) is defined as the stressful overexposure to high-intensity sounds. AOS is a precipitating factor that leads to a glutamate (GLU)-induced Type I auditory neural excitotoxicity and an activation of an immune/inflammatory/oxidative stress response within the inner ear, often resulting in cochlear hearing loss. The dendrites of the Type I auditory neural neurons that innervate the inner hair cells (IHCs), and respond to the IHC release of the excitatory neurotransmitter GLU, are themselves directly innervated by the dynorphin (DYN)-bearing axon terminals of the descending brain stem lateral olivocochlear (LOC) system. DYNs are known to increase GLU availability, potentiate GLU excitotoxicity, and induce superoxide production. DYNs also increase the production of proinflammatory cytokines by modulating immune/inflammatory signal transduction pathways. Evidence is provided supporting the possibility that the GLU-mediated Type I auditory neural dendritic swelling, inflammation, excitotoxicity, and cochlear hearing loss that follow AOS may be part of a brain stem-activated, DYN-mediated cascade of inflammatory events subsequent to a LOC release of DYNs into the cochlea. In support of a DYN-mediated cascade of events are established investigations linking DYNs to the immune/inflammatory/excitotoxic response in other neural systems.
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Affiliation(s)
- Tony L. Sahley
- Department of Biological, Geological, and Environmental Sciences, Cleveland State University, Cleveland, Ohio
- School of Health Sciences, Cleveland State University, Cleveland, Ohio
| | - David J. Anderson
- Department of Chemistry, Cleveland State University, Cleveland, Ohio
| | | | - Karthik Chandu
- Department of Chemistry, Cleveland State University, Cleveland, Ohio
| | - Frank E. Musiek
- Department of Speech, Language, and Hearing Sciences, University of Arizona, Tucson, Arizona
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36
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Sattler RA, Maruyama J, Shehu NY, Makishima T, Paessler S. Current small animal models for LASV hearing loss. Curr Opin Virol 2019; 37:118-122. [PMID: 31479989 DOI: 10.1016/j.coviro.2019.08.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2019] [Revised: 08/08/2019] [Accepted: 08/08/2019] [Indexed: 11/20/2022]
Abstract
Lassa virus (LASV) is endemic in West Africa, causing an estimated 100000-300000 new infections and up to 5000-10000 deaths yearly. There are no vaccines and therapeutics are extremely limited. Typical case fatality rates are ∼1%, although a recent 2018 Nigerian outbreak featured an unprecedented 25.4% case fatality rate. Survivors of infection suffer a lifetime of sequelae with sudden onset sensorineural hearing loss (SNHL) being the most prevalent. The cause of this hearing loss remains unknown, and there is a critical need for further research on its mechanisms and potential therapeutics. The objective of this review is to outline the only currently available small animal model for LASV-induced hearing loss and to identify potential surrogate models.
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Affiliation(s)
- Rachel A Sattler
- Department of Pathology, University of Texas Medical Branch, 301 University Blvd., Galveston, TX, 77551-0609, USA
| | - Junki Maruyama
- Department of Pathology, University of Texas Medical Branch, 301 University Blvd., Galveston, TX, 77551-0609, USA
| | - Nathan Y Shehu
- Department of Medicine, Infectious Disease Unit, Jos University Teaching Hospital, Jos, Plateau State, Nigeria
| | - Tomoko Makishima
- Department of Otolaryngology, University of Texas Medical Branch, 301 University Blvd., Galveston, TX, 77551-0609, USA
| | - Slobodan Paessler
- Department of Pathology, University of Texas Medical Branch, 301 University Blvd., Galveston, TX, 77551-0609, USA.
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37
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Köles L, Szepesy J, Berekméri E, Zelles T. Purinergic Signaling and Cochlear Injury-Targeting the Immune System? Int J Mol Sci 2019; 20:ijms20122979. [PMID: 31216722 PMCID: PMC6627352 DOI: 10.3390/ijms20122979] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2019] [Revised: 06/14/2019] [Accepted: 06/14/2019] [Indexed: 02/06/2023] Open
Abstract
Hearing impairment is the most common sensory deficit, affecting more than 400 million people worldwide. Sensorineural hearing losses currently lack any specific or efficient pharmacotherapy largely due to the insufficient knowledge of the pathomechanism. Purinergic signaling plays a substantial role in cochlear (patho)physiology. P2 (ionotropic P2X and the metabotropic P2Y) as well as adenosine receptors expressed on cochlear sensory and non-sensory cells are involved mostly in protective mechanisms of the cochlea. They are implicated in the sensitivity adjustment of the receptor cells by a K+ shunt and can attenuate the cochlear amplification by modifying cochlear micromechanics. Cochlear blood flow is also regulated by purines. Here, we propose to comprehend this field with the purine-immune interactions in the cochlea. The role of harmful immune mechanisms in sensorineural hearing losses has been emerging in the horizon of cochlear pathologies. In addition to decreasing hearing sensitivity and increasing cochlear blood supply, influencing the immune system can be the additional avenue for pharmacological targeting of purinergic signaling in the cochlea. Elucidating this complexity of purinergic effects on cochlear functions is necessary and it can result in development of new therapeutic approaches in hearing disabilities, especially in the noise-induced ones.
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Affiliation(s)
- László Köles
- Department of Pharmacology and Pharmacotherapy, Semmelweis University, H-1089 Budapest, Hungary.
| | - Judit Szepesy
- Department of Pharmacology and Pharmacotherapy, Semmelweis University, H-1089 Budapest, Hungary.
| | - Eszter Berekméri
- Department of Pharmacology and Pharmacotherapy, Semmelweis University, H-1089 Budapest, Hungary.
- Department of Ecology, University of Veterinary Medicine, H-1078 Budapest, Hungary.
| | - Tibor Zelles
- Department of Pharmacology and Pharmacotherapy, Semmelweis University, H-1089 Budapest, Hungary.
- Department of Pharmacology, Institute of Experimental Medicine, Hungarian Academy of Sciences, H-1083 Budapest, Hungary.
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38
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Warchol ME. Interactions between Macrophages and the Sensory Cells of the Inner Ear. Cold Spring Harb Perspect Med 2019; 9:cshperspect.a033555. [PMID: 30181352 DOI: 10.1101/cshperspect.a033555] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Macrophages are present in most somatic tissues, where they detect and attack invading pathogens. Macrophages also participate in many nonimmune functions, particularly those related to tissue maintenance and injury response. The sensory organs of the inner ear contain resident populations of macrophages, and additional macrophages enter the ear after acoustic trauma or ototoxicity. As expected, such macrophages participate in the clearance of cellular debris. However, otic macrophages can also influence the long-term survival of both hair cells and afferent neurons after injury. The signals that recruit macrophages into the injured ear, as well as the precise contributions of macrophages to inner ear pathology, remain to be determined.
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Affiliation(s)
- Mark E Warchol
- Department of Otolaryngology, Department of Neuroscience, Washington University School of Medicine, St. Louis, Missouri 63110
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39
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Mariano F, Mella A, Vincenti M, Biancone L. Furosemide as a functional marker of acute kidney injury in ICU patients: a new role for an old drug. J Nephrol 2019; 32:883-893. [PMID: 31090022 DOI: 10.1007/s40620-019-00614-1] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2019] [Accepted: 04/16/2019] [Indexed: 12/21/2022]
Abstract
New pharmacokinetics insight suggests that the furosemide pharmacology occurring in ICU patients with AKI is similar, but not equal to that described in chronic stable renal patients. Even if the diuretic response to furosemide is expressed by a steep dose-response curve positively correlated with renal function, pharmacodynamic limitations occur when creatinine clearance is < 20 ml/min or urine output is < 500 ml/12 h. In such cases, other factors specifically due to acute tubular injury can interfere with the furosemide-induced diuretic output. As modality of administration recent reports and metanalysis, even if not conclusive, suggest that for the same given dose a continuous infusion of furosemide was superior in diuretic response. For septic shock patients on CVVHDF where treatment adds an additional clearance of furosemide the maximum diuretic response is achieved by a continuous infusion of 20 mg/h of furosemide. At this infusion rate the reached plasma level was < 20 mg/L, a range considered safe and not ototoxic. Therefore, the severity of AKI establishes whether a patient will respond to furosemide. In this review we summarized all these recent updates, also suggesting that the diuretic response under continuous infusion may allow assessing glomerular and tubular functions with increased reliability than a bolus dose. However, validation studies are still needed to support continuous infusion as a stress test.
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Affiliation(s)
- Filippo Mariano
- Nephrology, Dialysis and Transplantation U, Department of Medical Sciences, CTO Hospital, University of Turin, City of Health and Science, Via G. Zuretti 29, 10126, Turin, Italy.
| | - Alberto Mella
- Nephrology, Dialysis and Transplantation U, Department of Medical Sciences, CTO Hospital, University of Turin, City of Health and Science, Via G. Zuretti 29, 10126, Turin, Italy
| | - Marco Vincenti
- Department of Chemistry, University of Turin, Turin, Italy
| | - Luigi Biancone
- Nephrology, Dialysis and Transplantation U, Department of Medical Sciences, CTO Hospital, University of Turin, City of Health and Science, Via G. Zuretti 29, 10126, Turin, Italy
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40
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Hong H, Dooley KE, Starbird LE, Francis HW, Farley JE. Adverse outcome pathway for aminoglycoside ototoxicity in drug-resistant tuberculosis treatment. Arch Toxicol 2019; 93:1385-1399. [PMID: 30963202 DOI: 10.1007/s00204-019-02407-8] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2018] [Accepted: 02/06/2019] [Indexed: 12/22/2022]
Abstract
Individuals treated for multidrug-resistant tuberculosis (MDR-TB) with aminoglycosides (AGs) in resource-limited settings often experience permanent hearing loss. However, AG ototoxicity has never been conceptually integrated or causally linked to MDR-TB patients' pre-treatment health condition. We sought to develop a framework that examines the relationships between pre-treatment conditions and AG-induced hearing loss among MDR-TB-infected individuals in sub-Saharan Africa. The adverse outcome pathway (AOP) approach was used to develop a framework linking key events (KEs) within a biological pathway that results in adverse outcomes (AO), which are associated with chemical perturbation of a molecular initiating event (MIE). This AOP describes pathways initiating from AG accumulation in hair cells, sound transducers of the inner ear immediately after AG administration. After administration, the drug catalyzes cellular oxidative stress due to overproduction of reactive oxygen species. Since oxidative stress inhibits mitochondrial protein synthesis, hair cells undergo apoptotic cell death, resulting in irreversible hearing loss (AO). We identified the following pre-treatment conditions that worsen the causal linkage between MIE and AO: HIV, malnutrition, aging, noise, smoking, and alcohol use. The KEs are: (1) nephrotoxicity, pre-existing hearing loss, and hypoalbuminemia that catalyzes AG accumulation; (2) immunodeficiency and antioxidant deficiency that trigger oxidative stress pathways; and (3) co-administration of mitochondrial toxic drugs that hinder mitochondrial protein synthesis, causing apoptosis. This AOP clearly warrants the development of personalized interventions for patients undergoing MDR-TB treatment. Such interventions (i.e., choosing less ototoxic drugs, scheduling frequent monitoring, modifying nutritional status, avoiding poly-pharmacy) will be required to limit the burden of AG ototoxicity.
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Affiliation(s)
- Hyejeong Hong
- Johns Hopkins University School of Nursing, 525 North Wolfe Street, Baltimore, MD, 21205, USA. .,Johns Hopkins University School of Nursing, The REACH Initiative, 855 N. Wolfe Street, 21205, Baltimore, MD, USA.
| | - Kelly E Dooley
- Divisions of Clinical Pharmacology and Infectious Disease, Johns Hopkins University School of Medicine, 600 North Wolfe Street, 21205, Baltimore, MD, USA
| | - Laura E Starbird
- Center for Health Policy, Columbia University School of Nursing, 560 W 168 St, 10032, New York, NY, USA
| | - Howard W Francis
- Division of Head and Neck Surgery and Communication Sciences, Duke University School of Medicine, 40 Duke Medicine Circle, 27710, Durham, NC, USA
| | - Jason E Farley
- Johns Hopkins University School of Nursing, 525 North Wolfe Street, Baltimore, MD, 21205, USA.,Johns Hopkins University School of Nursing, The REACH Initiative, 855 N. Wolfe Street, 21205, Baltimore, MD, USA
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41
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Kämpfe Nordström C, Danckwardt-Lillieström N, Laurell G, Liu W, Rask-Andersen H. The Human Endolymphatic Sac and Inner Ear Immunity: Macrophage Interaction and Molecular Expression. Front Immunol 2019; 9:3181. [PMID: 30774637 PMCID: PMC6367985 DOI: 10.3389/fimmu.2018.03181] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2018] [Accepted: 12/27/2018] [Indexed: 12/20/2022] Open
Abstract
Background: The endolymphatic sac (ES) is endowed with a multitude of white blood cells that may trap and process antigens that reach the inner ear from nearby infection-prone areas, it thus serves as an immunologic defense organ. The human ES, and unexpectedly the rest of the inner ear, has been recently shown to contain numerous resident macrophages. In this paper, we describe ES macrophages using super-resolution structured fluorescence microscopy (SR-SIM) and speculate on these macrophages' roles in human inner ear defense. Material and Methods: After ethical permission was obtained, human vestibular aqueducts were collected during trans-labyrinthine surgery for acoustic neuroma removal. Tissues were placed in fixative before being decalcified, rapidly frozen, and cryostat sectioned. Antibodies against IBA1, cytokine fractalkine (CX3CL1), toll-like receptor 4 (TLR4), cluster of differentiation (CD)68, CD11b, CD4, CD8, and the major histocompatibility complex type II (MHCII) were used for immunohistochemistry. Results: A large number of IBA1-positive cells with different morphologies were found to reside in the ES; the cells populated surrounding connective tissue and the epithelium. Macrophages interacted with other cells, showed migrant behavior, and expressed immune cell markers, all of which suggest their active role in the innate and adaptive inner ear defense and tolerance. Discussion: High-resolution immunohistochemistry shows that antigens reaching the ear may be trapped and processed by an immune cell machinery located in the ES. Thereby inflammatory activity may be evaded near the vulnerable inner ear sensory structures. We speculate on the immune defensive link between the ES and the rest of the inner ear.
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Affiliation(s)
- Charlotta Kämpfe Nordström
- Section of Otolaryngology, Department of Surgical Sciences, Uppsala University Hospital, Uppsala, Sweden
| | | | - Göran Laurell
- Section of Otolaryngology, Department of Surgical Sciences, Uppsala University Hospital, Uppsala, Sweden
| | - Wei Liu
- Section of Otolaryngology, Department of Surgical Sciences, Uppsala University Hospital, Uppsala, Sweden
| | - Helge Rask-Andersen
- Section of Otolaryngology, Department of Surgical Sciences, Head and Neck Surgery, Uppsala University Hospital, Uppsala, Sweden
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42
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Hirose K, Li SZ. The role of monocytes and macrophages in the dynamic permeability of the blood-perilymph barrier. Hear Res 2019; 374:49-57. [PMID: 30710792 DOI: 10.1016/j.heares.2019.01.006] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/01/2018] [Revised: 12/27/2018] [Accepted: 01/11/2019] [Indexed: 12/20/2022]
Abstract
The blood-perilymph barrier serves a critical role by separating the components of blood from inner ear fluids, limiting traffic of cells, proteins and other solutes into the labyrinth, and allowing gas (O2-CO2) exchange. Inflammation produces changes in the blood-perilymph barrier resulting in increased vascular permeability. It is commonly thought that compromise of the blood-inner ear barrier would lead to hearing impairment through loss of the endocochlear potential (EP). In fact, the effect of increasing cochlear vascular permeability on hearing function and EP is poorly understood. We used a novel method to measure the integrity of the blood-perilymph barrier and demonstrated the effects of barrier compromise on ABR threshold and EP. We also investigated the contribution of CX3CR1 cochlear macrophages and CCR2 inflammatory monocytes to barrier function after systemic exposure to lipopolysaccharide (LPS). We found that systemic LPS induced a profound change in vascular permeability, which correlated with minimal change in ABR threshold and EP. Macrophage depletion using CX3CR1-DTR mice did not alter the baseline permeability of cochlear vessels and resulted in preservation of barrier function in LPS-treated animals. We conclude that cochlear macrophages are not required to maintain the barrier in normal mice and activated macrophages are a critical factor in breakdown of the barrier after LPS. CCR2 null mice demonstrated that LPS induction of barrier leakiness occurs in the absence of CCR2 expression. Thus, enhanced aminoglycoside ototoxicity after LPS can be linked to the expression of CCR2 in inflammatory monocytes, and not to preservation of the blood-perilymph barrier in CCR2 knockout mice.
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Affiliation(s)
- Keiko Hirose
- Department of Otolaryngology, Washington University School of Medicine, St. Louis, Missouri, USA.
| | - Song-Zhe Li
- Department of Otolaryngology, Washington University School of Medicine, St. Louis, Missouri, USA
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43
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Herranen A, Ikäheimo K, Virkkala J, Pirvola U. The Stress Response in the Non-sensory Cells of the Cochlea Under Pathological Conditions-Possible Role in Mediating Noise Vulnerability. J Assoc Res Otolaryngol 2018; 19:637-652. [PMID: 30191426 DOI: 10.1007/s10162-018-00691-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2018] [Accepted: 07/08/2018] [Indexed: 10/28/2022] Open
Abstract
Various stressors, such as loud sounds and the effects of aging, impair the function and viability of the cochlear sensory cells, the hair cells. Stressors trigger pathophysiological changes in the cochlear non-sensory cells as well. We have here studied the stress response mounted in the lateral wall of the cochlea during acute noise stress and during age-related chronic stress. We have used the activation of JNK/c-Jun, ERK, and NF-κB pathways as a readout of the stress response, and the expression of the FoxO3 transcription factor as a possible additional player in cellular stress. In the aging cochlea, NF-κB transcriptional activity was strongly induced in the stria vascularis of the lateral wall. This induction was linked with the atrophy of the stria vascularis, suggesting a role for NF-κB signaling in mediating age-related strial degeneration. Acutely following noise exposure, the JNK/c-Jun, ERK, and NF-κB pathways were activated in the spiral ligament of the lateral wall of CBA/Ca mice. This activation was concomitant with the morphological transformation of macrophages, suggesting that the upregulation of stress signaling leads to macrophage activation. In contrast, C57BL/6J mice lacked these responses. Only the combination of noise exposure and a systemic stressor, lipopolysaccharide, exceeded the threshold for the activation of stress signaling in the lateral wall of C57BL/6J mice. In addition, we found that, at the young adult age, outer hair cells of CBA/Ca mice are much more vulnerable to loud sounds compared to these cells of C57BL/6J mice. These results suggest that the differential stress response in the lateral wall of the two mouse strains underlies, in part, the differential noise vulnerability of their outer hair cells. Together, we propose that the molecular stress response in the lateral wall modulates the outcome of the stressed cochlea.
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Affiliation(s)
- Anni Herranen
- Molecular and Integrative Biosciences Research Programme, Faculty of Biological and Environmental Sciences, University of Helsinki, Viikinkaari 1, P.O. Box 65, 00014, Helsinki, Finland
| | - Kuu Ikäheimo
- Molecular and Integrative Biosciences Research Programme, Faculty of Biological and Environmental Sciences, University of Helsinki, Viikinkaari 1, P.O. Box 65, 00014, Helsinki, Finland
| | - Jussi Virkkala
- Finnish Institute of Occupational Health, 00251, Helsinki, Finland
| | - Ulla Pirvola
- Molecular and Integrative Biosciences Research Programme, Faculty of Biological and Environmental Sciences, University of Helsinki, Viikinkaari 1, P.O. Box 65, 00014, Helsinki, Finland.
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44
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Sato T, Shapiro MG, Tsao DY. Ultrasonic Neuromodulation Causes Widespread Cortical Activation via an Indirect Auditory Mechanism. Neuron 2018; 98:1031-1041.e5. [PMID: 29804920 PMCID: PMC8127805 DOI: 10.1016/j.neuron.2018.05.009] [Citation(s) in RCA: 202] [Impact Index Per Article: 33.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2017] [Revised: 03/20/2018] [Accepted: 05/04/2018] [Indexed: 01/28/2023]
Abstract
Ultrasound has received widespread attention as an emerging technology for targeted, non-invasive neuromodulation based on its ability to evoke electrophysiological and motor responses in animals. However, little is known about the spatiotemporal pattern of ultrasound-induced brain activity that could drive these responses. Here, we address this question by combining focused ultrasound with wide-field optical imaging of calcium signals in transgenic mice. Surprisingly, we find cortical activity patterns consistent with indirect activation of auditory pathways rather than direct neuromodulation at the ultrasound focus. Ultrasound-induced activity is similar to that evoked by audible sound. Furthermore, both ultrasound and audible sound elicit motor responses consistent with a startle reflex, with both responses reduced by chemical deafening. These findings reveal an indirect auditory mechanism for ultrasound-induced cortical activity and movement requiring careful consideration in future development of ultrasonic neuromodulation as a tool in neuroscience research.
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Affiliation(s)
- Tomokazu Sato
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA.
| | - Mikhail G Shapiro
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA 91125, USA.
| | - Doris Y Tsao
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA; Howard Hughes Medical Institute, Pasadena, CA 91125, USA.
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45
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Hu BH, Zhang C, Frye MD. Immune cells and non-immune cells with immune function in mammalian cochleae. Hear Res 2018; 362:14-24. [PMID: 29310977 PMCID: PMC5911222 DOI: 10.1016/j.heares.2017.12.009] [Citation(s) in RCA: 58] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/15/2017] [Revised: 11/21/2017] [Accepted: 12/08/2017] [Indexed: 02/07/2023]
Abstract
The cochlea has an immune environment dominated by macrophages under resting conditions. When stressed, circulating monocytes enter the cochlea. These immune mediators, along with cochlear resident cells, organize a complex defense response against pathological challenges. Since the cochlea has minimal exposure to pathogens, most inflammatory conditions in the cochlea are sterile. Although the immune response is initiated for the protection of the cochlea, off-target effects can cause collateral damage to cochlear cells. A better understanding of cochlear immune capacity and regulation would therefore lead to development of new therapeutic treatments. Over the past decade, there have been many advances in our understanding of cochlear immune capacity. In this review, we provide an update and overview of the cellular components of cochlear immune capacity with a focus on macrophages in mammalian cochleae. We describe the composition and distribution of immune cells in the cochlea and suggest that phenotypic and functional characteristics of macrophages have site-specific diversity. We also highlight the response of immune cells to acute and chronic stresses and comment on the potential function of immune cells in cochlear homeostasis and disease development. Finally, we briefly review potential roles for cochlear resident cells in immune activities of the cochlea.
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Affiliation(s)
- Bo Hua Hu
- Center for Hearing and Deafness, University at Buffalo, 137 Cary Hall, 3435 Main Street, Buffalo, NY 14214, USA.
| | - Celia Zhang
- Center for Hearing and Deafness, University at Buffalo, 137 Cary Hall, 3435 Main Street, Buffalo, NY 14214, USA.
| | - Mitchell D Frye
- Center for Hearing and Deafness, University at Buffalo, 137 Cary Hall, 3435 Main Street, Buffalo, NY 14214, USA.
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Liu W, Molnar M, Garnham C, Benav H, Rask-Andersen H. Macrophages in the Human Cochlea: Saviors or Predators-A Study Using Super-Resolution Immunohistochemistry. Front Immunol 2018; 9:223. [PMID: 29487598 PMCID: PMC5816790 DOI: 10.3389/fimmu.2018.00223] [Citation(s) in RCA: 61] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2017] [Accepted: 01/26/2018] [Indexed: 12/20/2022] Open
Abstract
The human inner ear, which is segregated by a blood/labyrinth barrier, contains resident macrophages [CD163, ionized calcium-binding adaptor molecule 1 (IBA1)-, and CD68-positive cells] within the connective tissue, neurons, and supporting cells. In the lateral wall of the cochlea, these cells frequently lie close to blood vessels as perivascular macrophages. Macrophages are also shown to be recruited from blood-borne monocytes to damaged and dying hair cells induced by noise, ototoxic drugs, aging, and diphtheria toxin-induced hair cell degeneration. Precise monitoring may be crucial to avoid self-targeting. Macrophage biology has recently shown that populations of resident tissue macrophages may be fundamentally different from circulating macrophages. We removed uniquely preserved human cochleae during surgery for treating petroclival meningioma compressing the brain stem, after ethical consent. Molecular and cellular characterization using immunofluorescence with antibodies against IBA1, TUJ1, CX3CL1, and type IV collagen, and super-resolution structured illumination microscopy (SR-SIM) were made together with transmission electron microscopy. The super-resolution microscopy disclosed remarkable phenotypic variants of IBA1 cells closely associated with the spiral ganglion cells. Monitoring cells adhered to neurons with “synapse-like” specializations and protrusions. Active macrophages migrated occasionally nearby damaged hair cells. Results suggest that the human auditory nerve is under the surveillance and possible neurotrophic stimulation of a well-developed resident macrophage system. It may be alleviated by the non-myelinated nerve soma partly explaining why, in contrary to most mammals, the human’s auditory nerve is conserved following deafferentiation. It makes cochlear implantation possible, for the advantage of the profoundly deaf. The IBA1 cells may serve additional purposes such as immune modulation, waste disposal, and nerve regeneration. Their role in future stem cell-based therapy needs further exploration.
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Affiliation(s)
- Wei Liu
- Section of Otolaryngology, Department of Surgical Sciences, Uppsala University Hospital, Uppsala, Sweden
| | - Matyas Molnar
- Immunology, Genetics and Pathology - Biovis Platform, Uppsala University, Uppsala, Sweden
| | | | | | - Helge Rask-Andersen
- Head and Neck Surgery, Section of Otolaryngology, Department of Surgical Sciences, Uppsala University Hospital, Uppsala, Sweden
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Kim SH, Jung G, Kim S, Koo JW. Novel Peptide Vaccine GV1001 Rescues Hearing in Kanamycin/Furosemide-Treated Mice. Front Cell Neurosci 2018; 12:3. [PMID: 29403358 PMCID: PMC5780435 DOI: 10.3389/fncel.2018.00003] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2017] [Accepted: 01/03/2018] [Indexed: 12/25/2022] Open
Abstract
The cell-penetrating peptide GV1001 has been investigated as an anticancer agent and recently demonstrated anti-oxidant and anti-inflammatory effects. It has shown a protective effect on a kanamycin (KM)-induced ototoxicity mouse model. In the present study, we administered GV1001 at different time points after inducing hair cell damage, and examined if it rescues hair cell loss and restores hearing. A deaf mouse model was created by intraperitoneal injection of KM and furosemide. First, to test the early temporal change of hearing and extent of hair cell damage after KM and furosemide injection, hearing and outer hair cells (OHCs) morphology were evaluated on day 1, day 2 and day 3 after injection. In the second experiment, following KM and furosemide injection, GV1001, dexamethasone, or saline were given for three consecutive days at different time points: D0 group (days 0, 1, and 2), D1 group (days 1, 2, and 3), D3 group (days 3, 4, and 5) and D7 group (days 7, 8, and 9). The hearing thresholds were measured at 8, 16, and 32 kHz before ototoxic insult, and 7 days and 14 days after KM and furosemide injection. After 14 days, each turn of the cochlea was imaged to evaluate OHCs damage. GV1001-treated mice showed significantly less hearing loss and OHCs damage than the saline control group in the D0, D1 and D3 groups (p < 0.0167). However, there was no hearing restoration or intact hair cell in the D7 group. GV1001 protected against cochlear hair cell damage, and furthermore, delayed administration of GV1001 up to 3 days rescued hair cell damage and hearing loss in KM/furosemide-induced deaf mouse model.
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Affiliation(s)
- Shin Hye Kim
- Department of Otorhinolaryngology-Head and Neck Surgery, Korea University Medical Center, Korea University College of Medicine, Seoul, South Korea
| | - Gaon Jung
- Department of Otorhinolaryngology-Head and Neck Surgery, Seoul National University Bundang Hospital, Seoul National University College of Medicine, Seongnam, South Korea
| | - Sangjae Kim
- GemVax & Kael Co., Ltd, Seongnam, South Korea
| | - Ja-Won Koo
- Department of Otorhinolaryngology-Head and Neck Surgery, Seoul National University Bundang Hospital, Seoul National University College of Medicine, Seongnam, South Korea.,Sensory Organ Research Institute, Seoul National University Medical Research Center, Seoul, South Korea
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48
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Kaur T, Ohlemiller KK, Warchol ME. Genetic disruption of fractalkine signaling leads to enhanced loss of cochlear afferents following ototoxic or acoustic injury. J Comp Neurol 2017; 526:824-835. [PMID: 29218724 DOI: 10.1002/cne.24369] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2017] [Revised: 11/17/2017] [Accepted: 11/27/2017] [Indexed: 11/11/2022]
Abstract
Cochlear hair cells are vulnerable to a variety of insults like acoustic trauma and ototoxic drugs. Such injury can also lead to degeneration of spiral ganglion neurons (SGNs), but this occurs over a period of months to years. Neuronal survival is necessary for the proper function of cochlear prosthetics, therefore, it is of great interest to understand the mechanisms that regulate neuronal survival in deaf ears. We have recently demonstrated that selective hair cell ablation is sufficient to attract leukocytes into the spiral ganglion, and that fractalkine signaling plays a role in macrophage recruitment and in the survival of auditory neurons. Fractalkine (CX3 CL1), a chemokine that regulates adhesion and migration of leukocytes is expressed by SGNs and signals to leukocytes via its receptor CX3 CR1. The present study has extended the previous findings to more clinically relevant conditions of sensorineural hearing loss by examining the role of fractalkine signaling after aminoglycoside ototoxicity or acoustic trauma. Both aminoglycoside treatment and acoustic overstimulation led to the loss of hair cells as well as prolonged increase in the numbers of cochlear leukocytes. Lack of CX3 CR1 did not affect macrophage recruitment after injury, but resulted in increased loss of SGNs and enhanced expression of the inflammatory cytokine interleukin-1β, when compared to mice with intact CX3 CR1. These data indicate that the dysregulation of macrophage response caused by the absence of CX3 CR1 may contribute to inflammation-mediated neuronal loss in the deafened ear, suggesting a key role for inflammation in the long-term survival of target-deprived afferent neurons.
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Affiliation(s)
- Tejbeer Kaur
- Department of Otolaryngology, Washington University School of Medicine, St. Louis, Missouri
| | - Kevin K Ohlemiller
- Department of Otolaryngology, Washington University School of Medicine, St. Louis, Missouri
| | - Mark E Warchol
- Department of Otolaryngology, Washington University School of Medicine, St. Louis, Missouri
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Jiang M, Taghizadeh F, Steyger PS. Potential Mechanisms Underlying Inflammation-Enhanced Aminoglycoside-Induced Cochleotoxicity. Front Cell Neurosci 2017; 11:362. [PMID: 29209174 PMCID: PMC5702304 DOI: 10.3389/fncel.2017.00362] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2017] [Accepted: 11/03/2017] [Indexed: 12/20/2022] Open
Abstract
Aminoglycoside antibiotics remain widely used for urgent clinical treatment of life-threatening infections, despite the well-recognized risk of permanent hearing loss, i.e., cochleotoxicity. Recent studies show that aminoglycoside-induced cochleotoxicity is exacerbated by bacteriogenic-induced inflammation. This implies that those with severe bacterial infections (that induce systemic inflammation), and are treated with bactericidal aminoglycosides are at greater risk of drug-induced hearing loss than previously recognized. Incorporating this novel comorbid factor into cochleotoxicity risk prediction models will better predict which individuals are more predisposed to drug-induced hearing loss. Here, we review the cellular and/or signaling mechanisms by which host-mediated inflammatory responses to infection could enhance the trafficking of systemically administered aminoglycosides into the cochlea to enhance the degree of cochleotoxicity over that in healthy preclinical models. Once verified, these mechanisms will be potential targets for novel pharmacotherapeutics that reduce the risk of drug-induced hearing loss (and acute kidney damage) without compromising the life-saving bactericidal efficacy of aminoglycosides.
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Affiliation(s)
- Meiyan Jiang
- Oregon Hearing Research Center, Oregon Health & Science University, Portland, OR, United States
| | - Farshid Taghizadeh
- Oregon Hearing Research Center, Oregon Health & Science University, Portland, OR, United States
| | - Peter S Steyger
- Oregon Hearing Research Center, Oregon Health & Science University, Portland, OR, United States.,National Center for Rehabilitative Auditory Research, VA Portland Health Care System, Portland, OR, United States
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50
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Jiang M, Karasawa T, Steyger PS. Aminoglycoside-Induced Cochleotoxicity: A Review. Front Cell Neurosci 2017; 11:308. [PMID: 29062271 PMCID: PMC5640705 DOI: 10.3389/fncel.2017.00308] [Citation(s) in RCA: 171] [Impact Index Per Article: 24.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2017] [Accepted: 09/15/2017] [Indexed: 12/20/2022] Open
Abstract
Aminoglycoside antibiotics are used as prophylaxis, or urgent treatment, for many life-threatening bacterial infections, including tuberculosis, sepsis, respiratory infections in cystic fibrosis, complex urinary tract infections and endocarditis. Although aminoglycosides are clinically-essential antibiotics, the mechanisms underlying their selective toxicity to the kidney and inner ear continue to be unraveled despite more than 70 years of investigation. The following mechanisms each contribute to aminoglycoside-induced toxicity after systemic administration: (1) drug trafficking across endothelial and epithelial barrier layers; (2) sensory cell uptake of these drugs; and (3) disruption of intracellular physiological pathways. Specific factors can increase the risk of drug-induced toxicity, including sustained exposure to higher levels of ambient sound, and selected therapeutic agents such as loop diuretics and glycopeptides. Serious bacterial infections (requiring life-saving aminoglycoside treatment) induce systemic inflammatory responses that also potentiate the degree of ototoxicity and permanent hearing loss. We discuss prospective clinical strategies to protect auditory and vestibular function from aminoglycoside ototoxicity, including reduced cochlear or sensory cell uptake of aminoglycosides, and otoprotection by ameliorating intracellular cytotoxicity.
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Affiliation(s)
- Meiyan Jiang
- Oregon Hearing Research Center, Oregon Health & Science University, Portland, OR, United States
| | - Takatoshi Karasawa
- Oregon Hearing Research Center, Oregon Health & Science University, Portland, OR, United States
| | - Peter S Steyger
- Oregon Hearing Research Center, Oregon Health & Science University, Portland, OR, United States.,National Center for Rehabilitative Auditory Research, Portland VA Medical Center (VHA), Portland, OR, United States
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