Alan G. Cheng, MD

All Publications

• Precise genetic control of ATOH1 enhances maturation of regenerated hair cells in the mature mouse utricle. Nature communications Wang, T., Yang, T., Kedaigle, A., Pregernig, G., McCarthy, R., Holmes, B., Wu, X., Becker, L., Pan, N., So, K., Chen, L., He, J., Mahmoudi, A., Negi, S., Kowalczyk, M., Gibson, T., Druckenbrod, N., Cheng, A. G., Burns, J. 2024; 15 (1): 9166

  Abstract

  Vestibular hair cells are mechanoreceptors critical for detecting head position and motion. In mammals, hair cell loss causes vestibular dysfunction as spontaneous regeneration is nearly absent. Constitutive expression of exogenous ATOH1, a hair cell transcription factor, increases hair cell regeneration, however, these cells fail to fully mature. Here, we profiled mouse utricles at 14 time points, and defined transcriptomes of developing and mature vestibular hair cells. To mimic native hair cells which downregulate endogenous ATOH1 as they mature, we engineered viral vectors carrying the supporting cell promoters GFAP and RLBP1. In utricles damaged ex vivo, both CMV-ATOH1 and GFAP-ATOH1 increased regeneration more effectively than RLBP1-ATOH1, while GFAP-ATOH1 and RLBP1-ATOH1 induced hair cells with more mature transcriptomes. In utricles damaged in vivo, GFAP-ATOH1 induced regeneration of hair cells expressing genes indicative of maturing type II hair cells, and more hair cells with bundles and synapses than untreated organs. Together our results demonstrate the efficacy of spatiotemporal control of ATOH1 overexpression in inner ear hair cell regeneration.

  View details for DOI 10.1038/s41467-024-53153-0

  View details for PubMedID 39448563

  View details for PubMedCentralID 7173647

• Central Hearing Loss in a Pediatric Patient. The Laryngoscope Moon, P. K., Bloom, L., Tribble, M., Ling, A. H., Ahmad, I. N., Yeom, K., Cheng, A. G. 2024

  Abstract

  Sensorineural hearing loss is typically caused by dysfunction of the inner ear or auditory nerve. In pediatric patients diagnosed with sensorineural hearing loss, work-up often includes genetic testing and imaging studies of the auditory pathway. Here, we report a case of a pediatric patient with a history of sensorineural hearing loss following cisplatin and radiation therapy for brainstem medulloblastoma, developing symptoms and signs of central hearing loss based on audiometric and MRI/diffusion tensor imaging studies. Though rare, central hearing loss should be considered among the causes of sensorineural hearing loss in children. Laryngoscope, 2024.

  View details for DOI 10.1002/lary.31742

  View details for PubMedID 39323304

• Single-cell transcriptomic atlas reveals increased regeneration in diseased human inner ear balance organs. Nature communications Wang, T., Ling, A. H., Billings, S. E., Hosseini, D. K., Vaisbuch, Y., Kim, G. S., Atkinson, P. J., Sayyid, Z. N., Aaron, K. A., Wagh, D., Pham, N., Scheibinger, M., Zhou, R., Ishiyama, A., Moore, L. S., Maria, P. S., Blevins, N. H., Jackler, R. K., Alyono, J. C., Kveton, J., Navaratnam, D., Heller, S., Lopez, I. A., Grillet, N., Jan, T. A., Cheng, A. G. 2024; 15 (1): 4833

  Abstract

  Mammalian inner ear hair cell loss leads to permanent hearing and balance dysfunction. In contrast to the cochlea, vestibular hair cells of the murine utricle have some regenerative capacity. Whether human utricular hair cells regenerate in vivo remains unknown. Here we procured live, mature utricles from organ donors and vestibular schwannoma patients, and present a validated single-cell transcriptomic atlas at unprecedented resolution. We describe markers of 13 sensory and non-sensory cell types, with partial overlap and correlation between transcriptomes of human and mouse hair cells and supporting cells. We further uncover transcriptomes unique to hair cell precursors, which are unexpectedly 14-fold more abundant in vestibular schwannoma utricles, demonstrating the existence of ongoing regeneration in humans. Lastly, supporting cell-to-hair cell trajectory analysis revealed 5 distinct patterns of dynamic gene expression and associated pathways, including Wnt and IGF-1 signaling. Our dataset constitutes a foundational resource, accessible via a web-based interface, serving to advance knowledge of the normal and diseased human inner ear.

  View details for DOI 10.1038/s41467-024-48491-y

  View details for PubMedID 38844821

• Microstructural Changes in the Brainstem Auditory Pathway in Children With Hearing Loss. Otology & neurotology : official publication of the American Otological Society, American Neurotology Society [and] European Academy of Otology and Neurotology Moon, P. K., Ward, K. M., Din, T. F., Saki, S., Cheng, A. G., Yeom, K. W., Ahmad, I. N. 2024; 45 (3): e170-e176

  Abstract

  To assess the utility of diffusion tensor imaging of the auditory pathway in children with sensorineural hearing loss (SNHL).Retrospective cohort study.A single academic tertiary children's hospital.Sixteen pediatric patients with bilateral SNHL of at least moderate severity in the poorer ear (eight male; mean age, 5.3 ± 4.9 yrs). Controls consisted of age- and sex-matched children with normal hearing who were imaged for nonotologic, non-neurologic medical concerns and found to have normal magnetic resonance imaging (MRI).Three Tesla MRI scanners were used for diffusion tensor imaging.Quantitative diffusion tensor metrics were extracted from the superior olivary nucleus (SON), inferior colliculus (IC), and ipsilateral fiber tracts between the SON and IC delineated by tractography.We identified differences in fractional anisotropy of the SON between the SNHL cohort and controls (0.377 ± 0.056 vs. 0.422 ± 0.052; p = 0.009), but not in the IC. There were no differences in the mean diffusivity (MD) values in the IC and SON. Among younger children (≤5 yrs), MD was decreased in the SNHL cohort compared with controls in the IC (0.918 ± 0.051 vs. 1.120 ± 0.142; p < 0.001). However, among older children (>5 yrs), there were no differences in MD (1.124 ± 0.198 vs. 0.997 ± 0.103; p = 0.119). There were no differences in MD or fractional anisotropy in the white matter fibers of the IC-SON tract.Our results suggest abnormal neural tracts along the central auditory pathway among children with SNHL. Longitudinal studies should assess the prognostic value of these MRI-based findings for assessing long-term outcomes and determining intervention efficacy.

  View details for DOI 10.1097/MAO.0000000000004129

  View details for PubMedID 38361295

• Loss of Pax3 causes reduction of melanocytes in the developing mouse cochlea. Scientific reports Udagawa, T., Takahashi, E., Tatsumi, N., Mutai, H., Saijo, H., Kondo, Y., Atkinson, P. J., Matsunaga, T., Yoshikawa, M., Kojima, H., Okabe, M., Cheng, A. G. 2024; 14 (1): 2210

  Abstract

  Cochlear melanocytes are intermediate cells in the stria vascularis that generate endocochlear potentials required for auditory function. Human PAX3 mutations cause Waardenburg syndrome and abnormalities of skin and retinal melanocytes, manifested as congenital hearing loss (~ 70%) and hypopigmentation of skin, hair and eyes. However, the underlying mechanism of hearing loss remains unclear. Cochlear melanocytes in the stria vascularis originated from Pax3-traced melanoblasts and Plp1-traced Schwann cell precursors, both of which derive from neural crest cells. Here, using a Pax3-Cre knock-in mouse that allows lineage tracing of Pax3-expressing cells and disruption of Pax3, we found that Pax3 deficiency causes foreshortened cochlea, malformed vestibular apparatus, and neural tube defects. Lineage tracing and in situ hybridization show that Pax3+ derivatives contribute to S100+, Kir4.1+ and Dct+ melanocytes (intermediate cells) in the developing stria vascularis, all of which are significantly diminished in Pax3 mutant animals. Taken together, these results suggest that Pax3 is required for the development of neural crest cell-derived cochlear melanocytes, whose absence may contribute to congenital hearing loss of Waardenburg syndrome in humans.

  View details for DOI 10.1038/s41598-024-52629-9

  View details for PubMedID 38278860

  View details for PubMedCentralID PMC10817906

• Hair Cell Regeneration: From Animals to Humans. Clinical and experimental otorhinolaryngology Choi, S. W., Abitbol, J., Cheng, A. 2024

  Abstract

  Cochlear hair cells are critical in converting sound into electrical signals that are relayed via the spiral ganglion neurons to the central auditory pathway. Hair cells are vulnerable to damage caused by excessive noise, aging, and ototoxic agents. Non-mammals can regenerate lost hair cells by mitotic regeneration and direct transdifferentiation of surrounding supporting cells. However, in mature mammals, damaged hair cells are not replaced, resulting in permanent hearing loss. Recent studies have uncovered mechanisms by which sensory organs in non-mammals and the neonatal mammalian cochlea regenerate hair cells, and outlined possible mechanisms why this ability declines rapidly with age in mammals. Here, we review similarities and differences between avian, zebrafish and mammalian hair cell regeneration. Moreover, we discuss advances and limitations of hair cell regeneration in the mature cochlea and their potential applications to human hearing loss.

  View details for DOI 10.21053/ceo.2023.01382

  View details for PubMedID 38271988

• Is Public Interest Associated with Real-World Management of Ankyloglossia? Otolaryngology--head and neck surgery : official journal of American Academy of Otolaryngology-Head and Neck Surgery Naseem, D. F., Sheth, A. H., Cheng, A. G., Qian, Z. J. 2024

  Abstract

  Assess the relationship between public interest in ankyloglossia as determined by internet search volume and real-world medical claims data.Retrospective Cohort Study.This retrospective cohort study was conducted using claims data from the Merative™ Marketscan® Research Databases. The internet search data was collected from Google Trends.Annual Google Trends data were compiled using search terms associated with "ankyloglossia" and "frenotomy" for the years 2011 to 2021. We obtained incidence of ankyloglossia diagnoses and frenotomy procedures in children under 12 months from Marketscan relative to all infants enrolled. We compared associations between search and incidence data among US states and over time.Google search correlated with ankyloglossia incidence (r = 0.4104, P = .0031) and with frenotomy incidence (r = 0.4062, P = .0034) per state. Ankyloglossia diagnoses increased with Google search index (coefficient = 0.336, 95% confidence interval [CI] 0.284, 0.388) and year (coefficient = 0.028, 95% CI 0.025, 0.031). Similarly, frenotomy procedures increased with Google search index (coefficient = 0.371, 95% CI 0.313, 0.429) and year (coefficient = 0.027, 95% CI 0.024, 0.030).Associations between online ankyloglossia search trends and both diagnosis and treatment rates, persist across US regions and timeframes. Internet search trends are pivotal in shaping pediatric health care decisions, driving clinical consensus, and disseminating evidence-based information.

  View details for DOI 10.1002/ohn.643

  View details for PubMedID 38219744

• Selection of viral capsids and promoters affects the efficacy of rescue of Tmprss3-deficient cochlea. Molecular therapy. Methods & clinical development Aaron, K. A., Pekrun, K., Atkinson, P. J., Billings, S. E., Abitbol, J. M., Lee, I. A., Eltawil, Y., Chen, Y. S., Dong, W., Nelson, R. F., Kay, M. A., Cheng, A. G. 2023; 30: 413-428

  Abstract

  Adeno-associated virus (AAV)-mediated gene transfer has shown promise in rescuing mouse models of genetic hearing loss, but how viral capsid and promoter selection affects efficacy is poorly characterized. Here, we tested combinations of AAVs and promoters to deliver Tmprss3, mutations in which are associated with hearing loss in humans. Tmprss3tm1/tm1 mice display severe cochlear hair cell degeneration, loss of auditory brainstem responses, and delayed loss of spiral ganglion neurons. Under the ubiquitous CAG promoter and AAV-KP1 capsid, Tmprss3 overexpression caused striking cytotoxicity in vitro and in vivo and failed to rescue degeneration or dysfunction of the Tmprss3tm1/tm1 cochlea. Reducing the dosage or using AAV-DJ-CAG-Tmprss3 diminished cytotoxicity without rescue of the Tmprss3tm1/tm1 cochlea. Finally, the combination of AAV-KP1 capsid and the EF1α promoter prevented cytotoxicity and reduced hair cell degeneration, loss of spiral ganglion neurons, and improved hearing thresholds in Tmprss3tm1/tm1 mice. Together, our study illustrates toxicity of exogenous genes and factors governing rescue efficiency, and suggests that cochlear gene therapy likely requires precisely targeted transgene expression.

  View details for DOI 10.1016/j.omtm.2023.08.004

  View details for PubMedID 37663645

  View details for PubMedCentralID PMC10471831

• β-Catenin transcriptional activity is required for establishment of inner pillar cell identity during cochlear development. PLoS genetics Ebeid, M., Kishimoto, I., Roy, P., Zaidi, M. A., Cheng, A. G., Huh, S. H. 2023; 19 (8): e1010925

  Abstract

  The mammalian cochlea is composed of sensory hair cells as well as multiple different types of non-sensory supporting cells. Pillar cells are one type of supporting cell that form the tunnel of Corti and include two morphologically and functionally distinct subtypes: inner pillar cells (IPCs) and outer pillar cells (OPCs). The processes of specification and differentiation of inner versus outer pillar cells are still unclear. Here, we show that β-Catenin is required for establishing IPC identity in the mammalian cochlea. To differentiate the transcriptional and adhesion roles of β-Catenin in establishing IPC identity, we examined two different models of β-Catenin deletion; one that deletes both transcriptional and structural functions and one which retains cell adhesion function but lacks transcriptional function. Here, we show that cochleae lacking β-Catenin transcriptional function lost IPCs and displayed extranumerary OPCs, indicating its requirement for establishing IPC identity. Overexpression of β-Catenin induced proliferation within IPCs but not ectopic IPCs. Single-cell transcriptomes of supporting cells lacking β-Catenin transcriptional function show a loss of the IPC and gain of OPC signatures. Finally, targeted deletion of β-Catenin in IPCs also led to the loss of IPC identity, indicating a cell autonomous role of β-Catenin in establishing IPC identity. As IPCs have the capacity to regenerate sensory hair cells in the postnatal cochlea, our results will aid in future IPC-based hair cell regeneration strategies.

  View details for DOI 10.1371/journal.pgen.1010925

  View details for PubMedID 37639482

• Assessment of drug permeability through an exvivo porcine round window membrane model. iScience Moatti, A., Silkstone, D., Martin, T., Abbey, K., Hutson, K. A., Fitzpatrick, D. C., Zdanski, C. J., Cheng, A. G., Ligler, F. S., Greenbaum, A. 2023; 26 (6): 106789

  Abstract

  Delivery of pharmaceutical therapeutics to the inner ear to treat and prevent hearing loss is challenging. Systemic delivery is not effective as only a small fraction of the therapeutic agent reaches the inner ear. Invasive surgeries to inject through the round window membrane (RWM) or cochleostomy may cause damage to the inner ear. An alternative approach is to administer drugs into the middle ear using an intratympanic injection, with the drugs primarily passing through the RWM to the inner ear. However, the RWM is a barrier, only permeable to a small number of molecules. To study and enhance the RWM permeability, we developed an exvivo porcine RWM model, similar in structure and thickness to the human RWM. The model is viable for days, and drug passage can be measured at multiple time points. This model provides a straightforward approach to developing effective and non-invasive delivery methods to the inner ear.

  View details for DOI 10.1016/j.isci.2023.106789

  View details for PubMedID 37213232

• Ankyloglossia: Clinical and Sociodemographic Predictors of Diagnosis and Management in the United States, 2004 to 2019. Otolaryngology--head and neck surgery : official journal of American Academy of Otolaryngology-Head and Neck Surgery Wei, E. X., Meister, K. D., Balakrishnan, K., Cheng, A. G., Qian, Z. J. 2023

  Abstract

  OBJECTIVE: The past 2 decades have seen a rapid increase in the diagnosis of ankyloglossia. Patients are often managed by lingual frenotomy. The objective is to define the clinical and socioeconomic factors that determine which patients receive frenotomy.STUDY DESIGN: A retrospective analysis of commercially insured children.SETTING: Optum Data Mart database.METHODS: Trends in frenotomy including provider and setting were described. Multiple logistic regression was used to determine predictors of frenotomy.RESULTS: Diagnosis of ankyloglossia increased from 2004 to 2019 (from 3377 in 2004 to 13,200 in 2019), while lingual frenotomy similarly increased from 1483 in 2004 to 6213 in 2019. The proportion of inpatient frenotomy procedures increased from 6.2% to 16.6% from 2004 to 2019, with pediatricians having the highest odds of performing inpatient frenotomies (odds ratio:4.32, 95% confidence interval:4.08, 4.57). Additionally, during the study period, the proportion of frenotomies performed by pediatricians increased from 13.01% in 2004 to 28.38% in 2019. In multivariate regression analyses, frenotomy was significantly associated with the male sex, white non-Hispanic ethnicity, higher parental income and education, and a greater number of siblings.CONCLUSION: Ankyloglossia has been increasingly diagnosed in the past 2 decades, and amongpatients with ankyloglossia, frenotomy is increasingly performed. This trend was driven at least in part due to increasing rates of pediatricians as proceduralists. After accounting for maternal and patient-level clinical factors, socioeconomic differences in the management of ankyloglossia were observed.

  View details for DOI 10.1002/ohn.332

  View details for PubMedID 36994937

• Prevalence of Cochlear Nerve Deficiency and Hearing Device Use in Children With Single-Sided Deafness OTOLARYNGOLOGY-HEAD AND NECK SURGERY Ward, K. M., Coughran, A. J., Lee, M., Fitzgerald, M. B., Cheng, A. G., Chang, K. W., Ahmad, I. N. 2023

  View details for DOI 10.1002/ohn.255

  View details for Web of Science ID 000928877200001

• Prevalence of Cochlear Nerve Deficiency and Hearing Device Use in Children With Single-Sided Deafness. Otolaryngology--head and neck surgery : official journal of American Academy of Otolaryngology-Head and Neck Surgery Ward, K. M., Coughran, A. J., Lee, M., Fitzgerald, M. B., Cheng, A. G., Chang, K. W., Ahmad, I. N. 2023

  Abstract

  This study aimed to assess the prevalence of cochlear nerve deficiency (CND) in a cohort of pediatric patients with single-sided deafness (SSD). A secondary objective was to investigate trends in intervention and hearing device use in these children.Case series with chart review.Pediatric tertiary care center.Children ages 0 to 21 years with SSD (N = 190) who underwent computerized tomography (CT) and/or magnetic resonance imaging (MRI) were included. Diagnostic criteria for SSD included unilateral severe-to-profound sensorineural hearing loss with normal hearing sensitivity in the contralateral ear. Diagnostic criteria for CND included neuroradiologist report of an "aplastic or hypoplastic nerve" on MRI or a "stenotic cochlear aperture" on CT.The prevalence of CND was 42% for children with CT only, 76% for children with MRI only, and 63% for children with both MRI and CT. Of the children with MRI and CT, there was a 90% concordance across imaging modalities. About 36% of children with SSD had hearing devices that routed sound to the normal hearing ear (ie, bone conduction hearing device/contralateral routing of signal), while only 3% received a cochlear implant. Approximately 40% did not have a hearing device. Hearing device wear time averaged 2.9 hours per day and did not differ based on cochlear nerve status.There is a high prevalence of CND in children with SSD. Cochlear nerve status should be confirmed via MRI in children with SSD. The limited implementation and use of hearing devices observed for children with SSD reinforce the need for increased support for early and continuous intervention.

  View details for DOI 10.1002/ohn.255

  View details for PubMedID 36939463

• The impact of targeted ablation of one row of outer hair cells and Deiters' cells on cochlear amplification. Journal of neurophysiology Xia, A., Udagawa, T., Quinones, P. M., Atkinson, P. J., Applegate, B. E., Cheng, A. G., Oghalai, J. S. 2022

  Abstract

  The mammalian cochlea contains three rows of outer hair cells (OHCs) that amplify the basilar membrane traveling wave with high gain and exquisite tuning. The pattern of OHC loss caused by typical methods of producing hearing loss in animal models (noise, ototoxic exposure, or aging) is variable and not consistent along the length of the cochlea. Thus, it is difficult to use these approaches to understand how forces from multiple OHCs summate to create normal cochlear amplification. Here, we selectively removed the third row of OHCs and Deiters' cells in adult mice and measured cochlear amplification. In the mature cochlear epithelia, expression of the Wnt target gene Lgr5 is restricted to the third row of Deiters' cells, the supporting cells directly underneath the OHCs. Diphtheria toxin administration to Lgr5DTR-EGFP/+ mice selectively ablated the third row of Deiters' cells and the third row of OHCs. Basilar membrane vibration in vivo demonstrated disproportionately lower reduction in cochlear amplification by about 13.5 dB. On a linear scale, this means that the 33% reduction in OHC number led to a 79% reduction in gain. Thus, these experimental data describe the impact of reducing the force of cochlear amplification by a specific amount. Furthermore, these data argue that because OHC forces progressively and sequentially amplify the traveling wave as it travels to its peak, the loss of even a relatively small number of OHCs, when evenly distributed longitudinally, will cause a substantial reduction in cochlear amplification.

  View details for DOI 10.1152/jn.00501.2021

  View details for PubMedID 36259670

• Ontogeny of cellular organization and LGR5 expression in porcine cochlea revealed using tissue clearing and 3D imaging. iScience Moatti, A., Li, C., Sivadanam, S., Cai, Y., Ranta, J., Piedrahita, J. A., Cheng, A. G., Ligler, F. S., Greenbaum, A. 2022; 25 (8): 104695

  Abstract

  Over 11% of the world's population experience hearing loss. Although there are promising studies to restore hearing in rodent models, the size, ontogeny, genetics, and frequency range of hearing of most rodents' cochlea do not match that of humans. The porcine cochlea can bridge this gap as it shares many anatomical, physiological, and genetic similarities with its human counterpart. Here, we provide a detailed methodology to process and image the porcine cochlea in 3D using tissue clearing and light-sheet microscopy. The resulting3D images can be employed to compare cochleae across different ages and conditions, investigate the ontogeny of cochlear cytoarchitecture, and produce quantitative expression maps of LGR5, a marker of cochlear progenitors in mice. These data reveal that hair cell organization, inner ear morphology, cellular cartography in the organ of Corti, and spatiotemporal expression of LGR5 are dynamic over developmental stages in a pattern not previously documented.

  View details for DOI 10.1016/j.isci.2022.104695

  View details for PubMedID 35865132

• Repair of surviving hair cells in the damaged mouse utricle. Proceedings of the National Academy of Sciences of the United States of America Kim, G. S., Wang, T., Sayyid, Z. N., Fuhriman, J., Jones, S. M., Cheng, A. G. 2022; 119 (15): e2116973119

  Abstract

  SignificanceThe mammalian utricle shows limited hair cell regeneration despite partial recovery of function. Recovery of vestibular evoked potentials, a measure of utricular function, occurs after utricular hair cell damage in mammals. While previous work has shown limited regeneration in response to damage, most regenerating hair cells are type II with immature-appearing bundles. Whether hair cells that remain ("surviving hair cells") can self-repair and contribute to functional recovery is unknown. Using lineage tracing, we have characterized surviving hair cells over time and found that they repair bundles, regain innervation, and remain differentiated, and are therefore poised to contribute to the recovery of organ function.

  View details for DOI 10.1073/pnas.2116973119

  View details for PubMedID 35380897

• Identifying targets to prevent aminoglycoside ototoxicity. Molecular and cellular neurosciences Kim, J., Hemachandran, S., Cheng, A. G., Ricci, A. J. 2022: 103722

  Abstract

  Aminoglycosides are potent antibiotics that are commonly prescribed worldwide. Their use carries significant risks of ototoxicity by directly causing inner ear hair cell degeneration. Despite their ototoxic side effects, there are currently no approved antidotes. Here we review recent advances in our understanding of aminoglycoside ototoxicity, mechanisms of drug transport, and promising sites for intervention to prevent ototoxicity.

  View details for DOI 10.1016/j.mcn.2022.103722

  View details for PubMedID 35341941

• Use of Polysomnography and CPAP in Children Who Received Adenotonsillectomy, US 2004 to 2018. The Laryngoscope Qian, Z. J., Howard, J. M., Cohen, S. M., Jin, M. C., Bhargava, S., Cheng, A. G., Valdez, T. A. 2022

  Abstract

  OBJECTIVES: 1) To determine the prevalence polysomnogram (PSG) and continuous positive airway pressure (CPAP) therapy use in children who received adenotonsillectomy (AT) for sleep symptoms. 2) To identify health care disparities in these regards.STUDY DESIGN: Retrospective database analysis.METHODS: This study used data from Optum (Health Services Innovation Company) to identify 92,490 children who received AT for sleep symptoms between 2004 and 2018. Prevalence of preoperative PSG and postoperative PSG and CPAP were described. Clinical and demographic characteristics were compared between children who had preoperative PSG and those who did not. Characteristics of children with trisomy 21 (T21) were compared to assess PSG and CPAP use in a high-risk cohort. Predictive modeling was used to identify patient characteristics associated with postoperative PSG and CPAP use.RESULTS: Preoperative PSG was obtained in 5.5% of children overall and 33.2% of children with T21. Male sex, obesity, other medical comorbidities, non-White race/ethnicity, and higher parent education were associated with preoperative PSG. Fewer than 3% of children received postoperative PSGs and approximately 3% went on to receive CPAP therapy postoperatively. Multiple logistic regression showed that age at surgery, male sex, obesity, other medical comorbidities, non-White race/ethnicity, and higher parent education were associated with postoperative PSG and CPAP use.CONCLUSIONS AND RELEVANCE: This study described the prevalence pre-AT PSG use and post-AT PSG and CPAP use for persistent symptoms and identified sleep health care disparities in these regards. These results show that increased, equitable access to PSG is needed in children, particularly in the workup and treatment persistent symptoms after AT.LEVEL OF EVIDENCE: 4 Laryngoscope, 2022.

  View details for DOI 10.1002/lary.30103

  View details for PubMedID 35285524

• Surgical Approach for Rapid and Minimally Traumatic Recovery of Human Inner Ear Tissues from Deceased Organ Donors. Otology & neurotology : official publication of the American Otological Society, American Neurotology Society [and] European Academy of Otology and Neurotology Vaisbuch, Y., Hosseini, D. K., Wagner, A., Hirt, B., Mueller, M., Ponnusamy, R., Heller, S., Cheng, A. G., Lowenheim, H., Aaron, K. A. 2022

  Abstract

  OBJECTIVE: To develop a surgical approach for rapid and minimally traumatic recovery of inner ear tissue from human organ and tissue donors to provide fresh tissue for use in inner ear research.STUDY DESIGN: Exploration of novel surgical methodology and evaluation of the steps necessary for obtaining specimens from donors during the procurement of organs for transplantation.SETTING: Donor procurement locations across multiple local hospitals and tissue processing at the microsurgical temporal bone laboratory.PATIENTS TISSUE SOURCE: Human organ and tissue donors.INTERVENTIONS: Dissection and procurement of the inner ear tissue.MAIN OUTCOME MEASURES: Development of rapid and minimally traumatic inner ear tissue recovery. Primarily, establishing an efficient process which includes collaboration with transplant network, implementing a consent protocol, developing and training an on-call recovery team, and designing a portable surgical kit suitable for use in a variety of settings.RESULTS: The extraction procedure is described in three consecutive steps: the trans-canal exposure, the approach to the vestibule with extraction of the vestibular organs; and the approach to extract inner ear tissues from the cochlear duct.CONCLUSIONS: Organ and tissue donors are a promising and underutilized resource of inner ear organs for purposes of research and future translational studies. Using our modified technique through the trans-canal/trans-otic approach, we were able to extract tissues of the vestibular and auditory end organs in a timely manner.

  View details for DOI 10.1097/MAO.0000000000003500

  View details for PubMedID 35239617

• Infectious Complications Following Cochlear Implant: Risk Factors, Natural History, and Management Patterns. Otolaryngology--head and neck surgery : official journal of American Academy of Otolaryngology-Head and Neck Surgery Moon, P. K., Qian, Z. J., Ahmad, I. N., Stankovic, K. M., Chang, K. W., Cheng, A. G. 2022: 1945998221082530

  Abstract

  OBJECTIVE: To describe the natural history, detail the treatment patterns, and identify the risk factors for cochlear implant (CI) infections in a large US cohort.STUDY DESIGN: Retrospective study based on insurance claims.SETTING: Optum Data Mart database: 6101 patients who received CIs from 2003 to 2019.METHODS: Infections, treatments patterns, and timelines were described. A multivariable logistic regression model was used to assess the association between postoperative oral antibiotics and CI infection.RESULTS: The cohort includes 4736 (77.6%) adults and 1365 (22.4%) children. Between adult and pediatric patients, rates of CI infection (5.1% vs 4.5%, P = .18) and explantation (1.2% vs 0.8%, P = .11) were not significantly different. Infections typically occurred within 5 months of surgery. Children were diagnosed with CI infection earlier than adults (median difference, -1.5 months; P = .001). Postoperative oral antibiotic supply was not associated with lower risk of CI infection in either children or adults. However, among adults, otitis media was associated with higher odds of CI infection (odds ratio, 1.41; P < .001), while higher income was associated with lower odds of CI infection (odds ratio, 0.71; P = .03).CONCLUSIONS: Postoperative oral antibiotics were not associated with lower risk of infection or interventions. Otitis media episodes and lower income were associated with increased risk of infection among adults as well as intervention overall. Infection typically presented within the first 6 months after surgery, with children presenting earlier than adults. Overall, our findings serve as a resource for providers to consider in their care of patients with CIs.

  View details for DOI 10.1177/01945998221082530

  View details for PubMedID 35192408

• Selection Criteria Optimal for Recovery of Inner Ear Tissues from Deceased Organ Donors. Otology & neurotology : official publication of the American Otological Society, American Neurotology Society [and] European Academy of Otology and Neurotology Aaron, K. A., Hosseini, D. K., Vaisbuch, Y., Scheibinger, M., Grillet, N., Heller, S., Wang, T., Cheng, A. G. 2022

  Abstract

  To identify optimal conditions for recovering viable inner ear tissues from deceased organ donors.Tertiary recovery hospitals and Donor Network West Organ Recovery Center.Recovering bilateral inner ear tissues and immunohistological analysis.Immunohistochemical analysis of utricles from human organ donors after brain death (DBD) or donors after cardiac death (DCD).Vestibular tissues from 21 organ donors (39 ears) were recovered. Of these, 18 donors (33 utricles) were examined by immunofluorescence. The sensory epithelium was present in seven utricles (two from DBD and five from DCD). Relative to DBD utricles, DCD organs more commonly displayed dense populations of hair cells and supporting cells. Relative to DBD, DCD had significantly shorter postmortem interval time to tissue recovery (<48 h). Compared to donors with no sensory epithelium, donors with intact and viable sensory epithelium (both DCD and DBD) had significantly shorter lag time to resuscitation prior to hospital admission (6.4 ± 9.2 vs 35.6 ± 23.7 min, respectively) as well as a shorter time between pronouncements of death to organ recovery (22.6 ± 30.4 vs 64.8 ± 22.8 h, respectively).Organ donors are a novel resource for bilateral inner ear organs. Selecting tissue donors within defined parameters can optimize the quality of recovered inner ear tissues, thereby facilitating future research investigating sensory and nonsensory cells.

  View details for DOI 10.1097/MAO.0000000000003496

  View details for PubMedID 35120078

• Lineage-tracing and translatomic analysis of damage-inducible mitotic cochlear progenitors identifies candidate genes regulating regeneration. PLoS biology Udagawa, T., Atkinson, P. J., Milon, B., Abitbol, J. M., Song, Y., Sperber, M., Huarcaya Najarro, E., Scheibinger, M., Elkon, R., Hertzano, R., Cheng, A. G. 2021; 19 (11): e3001445

  Abstract

  Cochlear supporting cells (SCs) are glia-like cells critical for hearing function. In the neonatal cochlea, the greater epithelial ridge (GER) is a mitotically quiescent and transient organ, which has been shown to nonmitotically regenerate SCs. Here, we ablated Lgr5+ SCs using Lgr5-DTR mice and found mitotic regeneration of SCs by GER cells in vivo. With lineage tracing, we show that the GER houses progenitor cells that robustly divide and migrate into the organ of Corti to replenish ablated SCs. Regenerated SCs display coordinated calcium transients, markers of the SC subtype inner phalangeal cells, and survive in the mature cochlea. Via RiboTag, RNA-sequencing, and gene clustering algorithms, we reveal 11 distinct gene clusters comprising markers of the quiescent and damaged GER, and damage-responsive genes driving cell migration and mitotic regeneration. Together, our study characterizes GER cells as mitotic progenitors with regenerative potential and unveils their quiescent and damaged translatomes.

  View details for DOI 10.1371/journal.pbio.3001445

  View details for PubMedID 34758021

• MRI Correlates of Ototoxicity in the Auditory Pathway in Children Treated for Medulloblastoma. Otology & neurotology : official publication of the American Otological Society, American Neurotology Society [and] European Academy of Otology and Neurotology Moon, P., Theruvath, J., Chang, J., Song, Y., Shpanskaya, K., Maleki, M., Cheng, A. G., Ahmad, I. N., Yeom, K. W. 2021

  Abstract

  OBJECTIVE: To assess diffusion and perfusion changes of the auditory pathway in pediatric medulloblastoma patients exposed to ototoxic therapies.STUDY DESIGN: Retrospective cohort study.SETTING: A single academic tertiary children's hospital.PATIENTS: Twenty pediatric medulloblastoma patients (13 men; mean age 12.0 ± 4.8 yr) treated with platinum-based chemotherapy with or without radiation and 18 age-and-sex matched controls were included. Ototoxicity scores were determined using Chang Ototoxicity Grading Scale.INTERVENTIONS: Three Tesla magnetic resonance was used for diffusion tensor and arterial spin labeling perfusion imaging.MAIN OUTCOME MEASURES: Quantitative diffusion tensor metrics were extracted from the Heschl's gyrus, auditory radiation, and inferior colliculus. Arterial spin labeling perfusion of the Heschl's gyrus was also examined.RESULTS: Nine patients had clinically significant hearing loss, or Chang grades more than or equal to 2a; 11 patients had mild/no hearing loss, or Chang grades less than 2a. The clinically significant hearing loss group showed reduced mean diffusivity in the Heschl's gyrus (p = 0.018) and auditory radiation (p = 0.037), and decreased perfusion in the Heschl's gyrus (p = 0.001). Mild/no hearing loss group showed reduced mean diffusivity (p = 0.036) in Heschl's gyrus only, with a decrease in perfusion (p = 0.008). There were no differences between groups in the inferior colliculus. There was no difference in fractional anisotropy between patients exposed to ototoxic therapies and controls.CONCLUSIONS: Patients exposed to ototoxic therapies demonstrated microstructural and physiological alteration of the auditory pathway. The present study shows proof-of-concept use of diffusion tensor imaging to gauge ototoxicity along the auditory pathway. Future larger cohort studies are needed to assess significance of changes in diffusion tensor imaging longitudinally, and the relationship between these changes and hearing loss severity and longitudinal changes of the developing auditory white matter.

  View details for DOI 10.1097/MAO.0000000000003336

  View details for PubMedID 34739428

• Comments on Use of Diagnostic Testing and Intervention for Sensorineural Hearing Loss in US Children-Reply. JAMA otolaryngology-- head & neck surgery Qian, Z. J., Chang, K. W., Cheng, A. G. 2021

  View details for DOI 10.1001/jamaoto.2021.2162

  View details for PubMedID 34436534

• Trends and Healthcare Use Following Different Cholesteatoma Surgery Types in a National Cohort, 2003-2019. Otology & neurotology : official publication of the American Otological Society, American Neurotology Society [and] European Academy of Otology and Neurotology Qian, Z. J., Tran, E. D., Alyono, J. C., Cheng, A. G., Ahmad, I. N., Chang, K. W. 2021

  Abstract

  OBJECTIVE: To describe national trends in cholesteatoma management.STUDY DESIGN AND SETTING: Retrospective analysis Optum Clinformatics Database from 2003 to 2019.PATIENTS: 16,179 unique adult and pediatric patients who received cholesteatoma surgery.INTERVENTIONS AND MAIN OUTCOME MEASURES: Patients were categorized into three groups by initial surgical modality: canal wall down (CWD), canal wall up (CWU), and tympanoplasty without mastoidectomy (TnoM). Three major comparisons between groups were performed: 1) temporal trends, 2) clinical and sociodemographic determinants, and 3) healthcare use in terms of total costs and incidence of postoperative imaging and subsequent surgery.RESULTS: Overall, 23.2% received initial CWD surgery, 44.3% CWU, and 32.5% TnoM. 1) The incidence of initial CWD surgery decreased (odds ratios [OR] = 0.98, 95% confidence intervals [CI] [0.97,0.99]), while CWU increased (OR = 1.02, 95% CI [1.01,1.03]), and TnoM remained stable over the study period (OR = 0.99, 95% CI [0.98,1.00]). 2) Relative to CWU, TnoM surgery was less likely in adults, patients with prior complications, and non-White patients, while being more likely in patients with higher household income. CWD was more likely than CWU in adults, patients with prior complications, and non-White patients, while income had no effect. 3) Postoperative costs for CWU and CWD were similar. In 2 years following initial surgery, postoperative imaging and/or subsequent surgery was performed in 45.48% of CWD, 57.42% of CWU, and 41.62% of TnoM patients.CONCLUSIONS: Incidence of initial CWD surgery decreased and social disparities in cholesteatoma management were observed. Postoperative imaging or second-look surgery were performed in less than 60% of patients with initial CWU surgery and over 40% of patients with initial CWD.

  View details for DOI 10.1097/MAO.0000000000003284

  View details for PubMedID 34310551

• Spatiotemporal dynamics of inner ear sensory and non-sensory cells revealed by single-cell transcriptomics. Cell reports Jan, T. A., Eltawil, Y., Ling, A. H., Chen, L., Ellwanger, D. C., Heller, S., Cheng, A. G. 2021; 36 (2): 109358

  Abstract

  The utricle is a vestibular sensory organ that requires mechanosensitive hair cells to detect linear acceleration. In neonatal mice, new hair cells are derived from non-sensory supporting cells, yet cell type diversity and mechanisms of cell addition remain poorly characterized. Here, we perform computational analyses on single-cell transcriptomes to categorize cell types and resolve 14 individual sensory and non-sensory subtypes. Along the periphery of the sensory epithelium, we uncover distinct groups of transitional epithelial cells, marked by Islr, Cnmd, and Enpep expression. By reconstructing de novo trajectories and gene dynamics, we show that as the utricle expands, Islr+ transitional epithelial cells exhibit a dynamic and proliferative phase to generate new supporting cells, followed by coordinated differentiation into hair cells. Taken together, our study reveals a sequential and coordinated process by which non-sensory epithelial cells contribute to growth of the postnatal mouse sensory epithelium.

  View details for DOI 10.1016/j.celrep.2021.109358

  View details for PubMedID 34260939

• Imaging alloreactive T cells provides early warning of organ transplant rejection. JCI insight Hirai, T., Mayer, A. T., Nobashi, T. W., Lin, P., Xiao, Z., Udagawa, T., Seo, K., Simonetta, F., Baker, J., Cheng, A. G., Negrin, R. S., Gambhir, S. S. 2021; 6 (13)

  Abstract

  Diagnosis of organ transplant rejection relies upon biopsy approaches to confirm alloreactive T cell infiltration in the graft. Immune molecular monitoring is under investigation to screen for rejection, though these techniques have suffered from low specificity and lack of spatial information. ImmunoPET utilizing antibodies conjugated to radioisotopes has the potential to improve early and accurate detection of graft rejection. ImmunoPET is capable of noninvasively visualizing the dynamic distribution of cells expressing specific immune markers in the entire body over time. In this work, we identify and characterize OX40 as a surrogate biomarker for alloreactive T cells in organ transplant rejection and monitor its expression by utilizing immunoPET. In a dual murine heart transplant model that has both syngeneic and allogeneic hearts engrafted in bilateral ear pinna on the recipients, OX40 immunoPET clearly depicted alloreactive T cells in the allograft and draining lymph node that were not observed in their respective isograft counterparts. OX40 immunoPET signals also reflected the subject's immunosuppression level with tacrolimus in this study. OX40 immunoPET is a promising approach that may bridge molecular monitoring and morphological assessment for improved transplant rejection diagnosis.

  View details for DOI 10.1172/jci.insight.145360

  View details for PubMedID 34236044

• Assessment of auditory and vestibular damage in a mouse model after single and triple blast exposures. Hearing research Mao, B., Wang, Y., Balasubramanian, T., Urioste, R., Wafa, T., Fitzgerald, T. S., Haraczy, S. J., Edwards-Hollingsworth, K., Sayyid, Z. N., Wilder, D., Sajja, V. S., Wei, Y., Arun, P., Gist, I., Cheng, A. G., Long, J. B., Kelley, M. W. 2021; 407: 108292

  Abstract

  The use of explosive devices in war and terrorism has increased exposure to concussive blasts among both military personnel and civilians, which can cause permanent hearing and balance deficits that adversely affect survivors' quality of life. Significant knowledge gaps on the underlying etiology of blast-induced hearing loss and balance disorders remain, especially with regard to the effect of blast exposure on the vestibular system, the impact of multiple blast exposures, and long-term recovery. To address this, we investigated the effects of blast exposure on the inner ear using a mouse model in conjunction with a high-fidelity blast simulator. Anesthetized animals were subjected to single or triple blast exposures, and physiological measurements and tissue were collected over the course of recovery for up to 180 days. Auditory brainstem responses (ABRs) indicated significantly elevated thresholds across multiple frequencies. Limited recovery was observed at low frequencies in single-blasted mice. Distortion Product Otoacoustic Emissions (DPOAEs) were initially absent in all blast-exposed mice, but low-amplitude DPOAEs could be detected at low frequencies in some single-blast mice by 30 days post-blast, and in some triple-blast mice at 180 days post-blast. All blast-exposed mice showed signs of Tympanic Membrane (TM) rupture immediately following exposure and loss of outer hair cells (OHCs) in the basal cochlear turn. In contrast, the number of Inner Hair Cells (IHCs) and spiral ganglion neurons was unchanged following blast-exposure. A significant reduction in IHC pre-synaptic puncta was observed in the upper turns of blast-exposed cochleae. Finally, we found no significant loss of utricular hair cells or changes in vestibular function as assessed by vestibular evoked potentials. Our results suggest that (1) blast exposure can cause severe, long-term hearing loss which may be partially due to slow TM healing or altered mechanical properties of healed TMs, (2) traumatic levels of sound can still reach the inner ear and cause basal OHC loss despite middle ear dysfunction caused by TM rupture, (3) blast exposure may result in synaptopathy in humans, and (4) balance deficits after blast exposure may be primarily due to traumatic brain injury, rather than damage to the peripheral vestibular system.

  View details for DOI 10.1016/j.heares.2021.108292

  View details for PubMedID 34214947

• Opposing effects of Wnt/beta-catenin signaling on epithelial and mesenchymal cell fate in the developing cochlea. Development (Cambridge, England) Billings, S. E., Myers, N. M., Quiruz, L., Cheng, A. G. 2021; 148 (11)

  Abstract

  During embryonic development, the otic epithelium and surrounding periotic mesenchymal cells originate from distinct lineages and coordinate to form the mammalian cochlea. Epithelial sensory precursors within the cochlear duct first undergo terminal mitosis before differentiating into sensory and non-sensory cells. In parallel, periotic mesenchymal cells differentiate to shape the lateral wall, modiolus and pericochlear spaces. Previously, Wnt activation was shown to promote proliferation and differentiation of both otic epithelial and mesenchymal cells. Here, we fate-mapped Wnt-responsive epithelial and mesenchymal cells in mice and found that Wnt activation resulted in opposing cell fates. In the post-mitotic cochlear epithelium, Wnt activation via beta-catenin stabilization induced clusters of proliferative cells that dedifferentiated and lost epithelial characteristics. In contrast, Wnt-activated periotic mesenchyme formed ectopic pericochlear spaces and cell clusters showing a loss of mesenchymal and gain of epithelial features. Finally, clonal analyses via multi-colored fate-mapping showed that Wnt-activated epithelial cells proliferated and formed clonal colonies, whereas Wnt-activated mesenchymal cells assembled as aggregates of mitotically quiescent cells. Together, we show that Wnt activation drives transition between epithelial and mesenchymal states in a cell type-dependent manner.

  View details for DOI 10.1242/dev.199091

  View details for PubMedID 34061174

• Editorial: Epidemiology and Genetics of Vestibular Disorders. Frontiers in neurology Lopez-Escamez, J. A., Cheng, A. G., Grill, E., Liu, T. 2021; 12: 743379

  View details for DOI 10.3389/fneur.2021.743379

  View details for PubMedID 34630314

• Gpr125 Marks Distinct Cochlear Cell Types and Is Dispensable for Cochlear Development and Hearing. Frontiers in cell and developmental biology Sun, H., Wang, T., Atkinson, P. J., Billings, S. E., Dong, W., Cheng, A. G. 2021; 9: 690955

  Abstract

  The G protein-coupled receptor (GPR) family critically regulates development and homeostasis of multiple organs. As a member of the GPR adhesion family, Gpr125 (Adgra3) modulates Wnt/PCP signaling and convergent extension in developing zebrafish, but whether it is essential for cochlear development in mammals is unknown. Here, we examined the Gpr125 lacZ/+ knock-in mice and show that Gpr125 is dynamically expressed in the developing and mature cochleae. From embryonic day (E) 15.5 to postnatal day (P) 30, Gpr125-beta-Gal is consistently expressed in the lesser epithelial ridge and its presumed progenies, the supporting cell subtypes Claudius cells and Hensen's cells. In contrast, Gpr125-beta-Gal is expressed transiently in outer hair cells, epithelial cells in the lateral cochlear wall, interdental cells, and spiral ganglion neurons in the late embryonic and early postnatal cochlea. In situ hybridization for Gpr125 mRNA confirmed Gpr125 expression and validated loss of expression in Gpr125 lacZ/lacZ cochleae. Lastly, Gpr125 lacZ/+ and Gpr125 lacZ/ lacZ cochleae displayed no detectable loss or disorganization of either sensory or non-sensory cells in the embryonic and postnatal ages and exhibited normal auditory physiology. Together, our study reveals that Gpr125 is dynamically expressed in multiple cell types in the developing and mature cochlea and is dispensable for cochlear development and hearing.

  View details for DOI 10.3389/fcell.2021.690955

  View details for PubMedID 34395423

• Outpatient healthcare use and outcomes after pediatric tracheostomy. International journal of pediatric otorhinolaryngology Qian, Z. J., Megwalu, U. C., Cheng, A. G., Balakrishnan, K. 2021; 151: 110963

  Abstract

  To 1) describe health outcomes and outpatient healthcare use after pediatric tracheostomy, and 2) identify populations with higher morbidity that may benefit from improved post-operative monitoring.Optum's commercial insurance database was queried from 2003 to 2019. Children aged 0-18 who received tracheostomy identified. Mortality, decannulation, tracheostomy complications, and home ventilator dependence were determined, as well as physician office visits and specialty type. The effect that patient characteristics (age, sex, ethnicity, prematurity, and presence versus absence of chronic lung disease [CLD], congenital heart disease [CHD], neurologic impairment [NI], and upper airway obstruction [UAO]) had on outcomes were compared.1231 children were identified. Infants accounted for 33% of patients and 40% of the cohort was premature. The most common comorbid conditions were NI (76%), UAO (69%), CLD (48%), and CHD (35%). Within 5 years postoperatively, 25% died, 45% had home ventilator dependence, 53% had a complication, and 10% were decannulated. CHD was associated with higher risk of death (HR,1.98; 95% CI 1.22, 3.21), while UAO was associated with lower risk of death (HR,0.51; 95% CI 0.32, 0.83) and higher probability of decannulation (HR,3.56, 95% CI 1.08, 11.74). The median number of physician office visits was 6 per year (IQR 3,10). The most common specialty types were pediatrics (32%), pulmonary medicine (10%), and otolaryngology (8%). NI was associated with greater number of office visits (mean difference/year, 4.10; 95% CI 2.00, 6.19) while Hispanic ethnicity was associated with fewer visits (mean difference/year, -2.94; 95%CI -5.42, -0.45).UAO was associated with lower risk of mortality and higher probability of decannulation, while NI was associated with greater outpatient healthcare utilization. Social disparities in outpatient tracheostomy care were observed.

  View details for DOI 10.1016/j.ijporl.2021.110963

  View details for PubMedID 34736006

• Use of Diagnostic Testing and Intervention for Sensorineural Hearing Loss in US Children From 2008 to 2018. JAMA otolaryngology-- head & neck surgery Qian, Z. J., Chang, K. W., Ahmad, I. N., Tribble, M. S., Cheng, A. G. 2020

  Abstract

  Importance: Early detection and intervention of pediatric hearing loss is critical for language development and academic achievement. However, variations in the diagnostic workup and management of pediatric sensorineural hearing loss (SNHL) exist.Objective: To identify patient and clinician factors that are associated with variation in practice on a national level.Design, Setting, and Participants: This cross-sectional study used the Optum claims database to identify 53 711 unique children with SNHL between January 1, 2008, and December 31, 2018.Main Outcomes and Measures: National use rates and mean costs for diagnostic modalities (electrocardiogram, cytomegalovirus testing, magnetic resonance imaging, computed tomography, and genetic testing) and interventions (speech-language pathology, billed hearing aid services, and cochlear implant surgery) were reported. The associations of age, sex, SNHL laterality, clinician type, race/ethnicity, and household income with diagnostic workup and intervention use were measured in multivariable analyses.Results: Of 53 711 patients, 23 735 (44.2%) were girls, 2934 (5.5%) were Asian, 3797 (7.1%) were Black, 5626 (10.5%) were Hispanic, 33 441 (62.3%) were White, and the mean (SD) age was 7.3 (5.3) years. Of all patients, 32 200 (60.0%) were seen by general otolaryngologists, while 7573 (14.10%) were seen by pediatric otolaryngologists. Diagnostic workup was received by 14 647 patients (27.3%), while 13 482 (25.1%) received intervention. Use of genetic testing increased (odds ratio, 1.22 per year; 95% CI, 1.20-1.24), whereas use of computed tomography decreased (odds ratio, 0.93 per year; 95% CI, 0.92-0.94) during the study period. After adjusting for relevant covariables, children who were seen by pediatric otolaryngologists and geneticists had the highest odds of receiving workup and intervention. Additionally, racial/ethnic and economic disparities were observed in the use of most modalities of diagnostic workup and intervention for pediatric SNHL.Conclusions and Relevance: This cross-sectional study identified factors associated with disparities in the diagnostic workup and intervention of pediatric SNHL, thus highlighting the need for increased education and standardization in the management of this common sensory disorder.

  View details for DOI 10.1001/jamaoto.2020.5030

  View details for PubMedID 33377936

• Dissociating antibacterial from ototoxic effects of gentamicin C-subtypes. Proceedings of the National Academy of Sciences of the United States of America O'Sullivan, M. E., Song, Y., Greenhouse, R., Lin, R., Perez, A., Atkinson, P. J., MacDonald, J. P., Siddiqui, Z., Lagasca, D., Comstock, K., Huth, M. E., Cheng, A. G., Ricci, A. J. 2020

  Abstract

  Gentamicin is a potent broad-spectrum aminoglycoside antibiotic whose use is hampered by ototoxic side-effects. Hospital gentamicin is a mixture of five gentamicin C-subtypes and several impurities of various ranges of nonexact concentrations. We developed a purification strategy enabling assaying of individual C-subtypes and impurities for ototoxicity and antimicrobial activity. We found that C-subtypes displayed broad and potent in vitro antimicrobial activities comparable to the hospital gentamicin mixture. In contrast, they showed different degrees of ototoxicity in cochlear explants, with gentamicin C2b being the least and gentamicin C2 the most ototoxic. Structure-activity relationships identified sites in the C4'-C6' region on ring I that reduced ototoxicity while preserving antimicrobial activity, thus identifying targets for future drug design and mechanisms for hair cell toxicity. Structure-activity relationship data suggested and electrophysiological data showed that the C-subtypes both bind and permeate the hair cell mechanotransducer channel, with the stronger the binding the less ototoxic the compound. Finally, both individual and reformulated mixtures of C-subtypes demonstrated decreased ototoxicity while maintaining antimicrobial activity, thereby serving as a proof-of-concept of drug reformulation to minimizing ototoxicity of gentamicin in patients.

  View details for DOI 10.1073/pnas.2013065117

  View details for PubMedID 33288712

• Opioid Prescribing Patterns Following Pediatric Tonsillectomy in the United States, 2009-2017. The Laryngoscope Qian, Z. J., Alyono, J. C., Jin, M. C., Cooperman, S. P., Cheng, A. G., Balakrishnan, K. 2020

  Abstract

  OBJECTIVES: Assess national trends in opioid prescription following pediatric tonsillectomy: 1) overall percentage receiving opioids and mean quantity, 2) changes during 2009-2017, and 3) determinants of prescription patterns.METHODS: Cross-sectional analysis using 2009-2017 Optum claims data to identify opioid-naive children aged 1-18 with claims codes for tonsillectomy (n = 82,842). Quantities of opioids filled in outpatient pharmacies during the perioperative period were extracted and converted into milligram morphine equivalents (MMEs) for statistical comparison. Demographic, clinical, and socioeconomic predictors of opioid fill rate and quantity were determined using regression analyses.RESULTS: In 2009, 83.3% of children received opioids, decreasing to 58.3% by 2017. Rates of all-cause readmissions and post-tonsillectomy hemorrhages were similar over time. Mean quantity received was 153.47MME (95% confidence intervals [95%CI]: 151.19, 155.76) and did not significantly change during 2009-2017. Opioids were more likely in older children and those with higher household income, but less likely in children with obstructive sleep apnea, other comorbidities, and Hispanic race. Higher quantities of opioids were more likely in older children, while lower quantities were associated with female sex, Hispanic race, and higher household income. Outpatient steroids were prescribed to 8.04% of patients, who were less likely to receive opioids.CONCLUSION: While the percentage of children receiving post-tonsillectomy opioids decreased during 2009-2017, prescribed quantities remain high and have not decreased over time. Prescription practices were also influenced by clinical and sociodemographic factors. These results highlight the need for guidance, particularly with regard to opioid quantity, in children after tonsillectomy.LEVEL OF EVIDENCE: N/A Laryngoscope, 2020.

  View details for DOI 10.1002/lary.29159

  View details for PubMedID 33026683

• Advances in Inner Ear Therapeutics for Hearing Loss in Children. Current otorhinolaryngology reports Aaron, K. A., Kim, G. S., Cheng, A. G. 2020; 8 (3): 285-294

  Abstract

  Hearing loss is a common congenital sensory disorder with various underlying causes. Here, we review and focus on genetic, infectious, and ototoxic causes and recent advances in inner ear therapeutics.While hearing aids and cochlear implantation are the mainstay of treatment for pediatric hearing loss, novel biological therapeutics are being explored. Recent preclinical studies report positive results in viral-mediated gene transfer techniques and surgical approaches to the inner ear for genetic hearing loss. Novel pharmacologic agents, on the other hand, show promising results in reducing aminoglycoside and cisplatin ototoxicity. Clinical trials are underway to evaluate the efficacy of antivirals for cytomegalovirus-related hearing loss, and its pathogenesis and other potential therapeutics are currently under investigation.Individualized therapies for genetic and infectious causes of sensorineural hearing loss in animal models as well as pediatric patients show promising results, with their potential efficacy being active areas of research.

  View details for DOI 10.1007/s40136-020-00300-y

  View details for PubMedID 36090148

  View details for PubMedCentralID PMC9455742

• Congenital Orocutaneous Fistula Associated With Ectopic Salivary Glands and Submandibular Gland Aplasia. The Laryngoscope Trieu, V., Hosseini, D. K., Kim, G. S., Truong, M. T., Cheng, A. G. 2020

  View details for DOI 10.1002/lary.28921

  View details for PubMedID 33059385

• Cerebral volume and diffusion MRI changes in children with sensorineural hearing loss. NeuroImage. Clinical Moon, P. K., Qian, J. Z., McKenna, E. n., Xi, K. n., Rowe, N. C., Ng, N. N., Zheng, J. n., Tam, L. T., MacEachern, S. J., Ahmad, I. n., Cheng, A. G., Forkert, N. D., Yeom, K. W. 2020; 27: 102328

  Abstract

  Sensorineural hearing loss (SNHL) is the most prevalent congenital sensory deficit in children. Information regarding underlying brain microstructure could offer insight into neural development in deaf children and potentially guide therapies that optimize language development. We sought to quantitatively evaluate MRI-based cerebral volume and gray matter microstructure children with SNHL.We conducted a retrospective study of children with SNHL who obtained brain MRI at 3 T. The study cohort comprised 63 children with congenital SNHL without known focal brain lesion or structural abnormality (33 males; mean age 5.3 years; age range 1 to 11.8 years) and 64 age-matched controls without neurological, developmental, or MRI-based brain macrostructure abnormality. An atlas-based analysis was used to extract quantitative volume and median diffusivity (ADC) in the following brain regions: cerebral cortex, thalamus, caudate, putamen, globus pallidus, hippocampus, amygdala, nucleus accumbens, brain stem, and cerebral white matter. SNHL patients were further stratified by severity scores and hearing loss etiology.Children with SNHL showed higher median ADC of the cortex (p = .019), thalamus (p < .001), caudate (p = .005), and brainstem (p = .003) and smaller brainstem volumes (p = .007) compared to controls. Patients with profound bilateral SNHL did not show any significant differences compared to patients with milder bilateral SNHL, but both cohorts independently had smaller brainstem volumes compared to controls. Children with unilateral SNHL showed greater amygdala volumes compared to controls (p = .021), but no differences were found comparing unilateral SNHL to bilateral SNHL. Based on etiology for SNHL, patients with Pendrin mutations showed higher ADC values in the brainstem (p = .029, respectively); patients with Connexin 26 showed higher ADC values in both the thalamus (p < .001) and brainstem (p < .001) compared to controls.SNHL patients showed significant differences in diffusion and volume in brain subregions, with region-specific findings for patients with Connexin 26 and Pendrin mutations. Future longitudinal studies could examine macro- and microstructure changes in children with SNHL over development and potential predictive role for MRI after interventions including cochlear implant outcome.

  View details for DOI 10.1016/j.nicl.2020.102328

  View details for PubMedID 32622314

• Dual regulation of planar polarization by secreted Wnts and Vangl2 in the developing mouse cochlea. Development (Cambridge, England) Huarcaya Najarro, E., Huang, J., Jacobo, A., Quiruz, L. A., Grillet, N., Cheng, A. G. 2020

  Abstract

  Planar cell polarity (PCP) proteins localize asymmetrically to instruct cell polarity within the tissue plane, with defects leading to deformities of the limbs, neural tube, and inner ear. Wnt proteins are evolutionarily conserved polarity cues, yet Wnt mutants display variable PCP defects, thus how Wnts regulate PCP remains unresolved. Here, we used the developing cochlea as a model system to show that secreted Wnts regulate PCP through polarizing a specific subset of PCP proteins. Conditional deletion of Wntless or Porcupine, both essential for secretion of Wnts, caused misrotated sensory cells and shortened cochlea-both hallmarks of PCP defects. Wntless-deficient cochleae lacked the polarized PCP components Dishevelled1/2 and Frizzled3/6, while other PCP proteins (Vangl1/2, Celsr1, Dishevelled3) remained localized. We identified seven Wnt paralogues, including the major PCP regulator Wnt5a, which was surprisingly dispensable for planar polarization in the cochlea. Finally, Vangl2 haploinsufficiency markedly accentuated sensory cell polarization defects in Wntless-deficient cochlea. Together, our study indicates that secreted Wnts and Vangl2 coordinate to ensure proper tissue polarization during development.

  View details for DOI 10.1242/dev.191981

  View details for PubMedID 34004910

• Congenital Hearing Loss Is Associated With a High Incidence of Central Nervous System Abnormalities. Otology & neurotology : official publication of the American Otological Society, American Neurotology Society [and] European Academy of Otology and Neurotology Sayyid, Z. N., Boldt, B. n., Mokhtari, T. E., Schoppy, K. n., Yeom, K. W., Cheng, A. G. 2020

  Abstract

  To assess the incidence of central nervous system abnormalities in pediatric subjects with sensorineural hearing loss (SNHL).One hundred forty-three pediatric subjects evaluated for SNHL at a single academic center from 2007 to 2014 were included and divided into eight diagnosis groups based on etiology of SNHL. One hundred forty-three age- and gender-matched control subjects with no known brain-related pathology or history of hearing loss were included as healthy controls for comparison. Two neuroradiologists independently evaluated magnetic resonance imaging (MRI) and computed tomography (CT) scans for each subject. Comparison of abnormal cerebral development was performed using an ordinal logistic regression model. Concordance between CT and MRI of the temporal bone was assessed using the kappa statistic.The etiologies of hearing loss in our cohort were 37.8% genetic, 12.6% infectious, 1.4% ototoxin-induced, and 48.3% idiopathic. Brain MRI revealed cerebral developmental abnormalities in defined regions in >30% of the SNHL cohort, significantly more than in normal-hearing pediatric controls. The Sylvian fissure, Virchow-Robin spaces, and lateral ventricles were most commonly affected. In the temporal bone, the percentage of subjects with concordant findings on CT and MRI was ≥92% across all anatomical structures.MRI revealed a high incidence of intracranial abnormalities, suggestive of aberrant development of auditory and nonauditory neural structures associated with SNHL. CT and MRI share a high degree of concordance in detecting temporal bone anomalies. Inclusion of MRI as part of the workup of congenital SNHL may facilitate the detection of developmental anomalies of the brain associated with SNHL.

  View details for DOI 10.1097/MAO.0000000000002778

  View details for PubMedID 32740546

• Dual regulation of planar polarization by secreted Wnts and Vangl2 in the developing mouse cochlea. Development (Cambridge, England) Huarcaya Najarro, E. n., Huang, J. n., Jacobo, A. n., Quiruz, L. A., Grillet, N. n., Cheng, A. G. 2020

  Abstract

  Planar cell polarity (PCP) proteins localize asymmetrically to instruct cell polarity within the tissue plane, with defects leading to deformities of the limbs, neural tube, and inner ear. Wnt proteins are evolutionarily conserved polarity cues, yet Wnt mutants display variable PCP defects, thus how Wnts regulate PCP remains unresolved. Here, we used the developing cochlea as a model system to show that secreted Wnts regulate PCP through polarizing a specific subset of PCP proteins. Conditional deletion of Wntless or Porcupine, both essential for secretion of Wnts, caused misrotated sensory cells and shortened cochlea-both hallmarks of PCP defects. Wntless-deficient cochleae lacked the polarized PCP components Dishevelled1/2 and Frizzled3/6, while other PCP proteins (Vangl1/2, Celsr1, Dishevelled3) remained localized. We identified seven Wnt paralogues, including the major PCP regulator Wnt5a, which was surprisingly dispensable for planar polarization in the cochlea. Finally, Vangl2 haploinsufficiency markedly accentuated sensory cell polarization defects in Wntless-deficient cochlea. Together, our study indicates that secreted Wnts and Vangl2 coordinate to ensure proper tissue polarization during development.

  View details for DOI 10.1242/dev.191981

  View details for PubMedID 32907846

• International Pediatric Otolaryngology Group (IPOG) Consensus Recommendations: Congenital Cholesteatoma. Otology & neurotology : official publication of the American Otological Society, American Neurotology Society [and] European Academy of Otology and Neurotology Denoyelle, F., Simon, F., Chang, K. W., Chan, K. H., Cheng, A. G., Cheng, A. T., Choo, D. I., Daniel, S. J., Farinetti, A., Garabedian, E., Greinwald, J. H., Hoff, S. R., Hone, S., Licameli, G. R., Papsin, B. C., Poe, D. S., Pransky, S., Smith, R. J., Triglia, J., Walton, J., Zalzal, G., Leboulanger, N. 2019

  Abstract

  OBJECTIVE: To provide recommendations to otolaryngologists and allied physicians for the comprehensive management of children who present with signs and symptoms of congenital cholesteatoma.METHODS: A two-iterative Delphi method questionnaire was used to establish expert recommendations by the members of the International Pediatric Otolaryngology Group, on the preoperative work-up, the perioperative considerations, and follow-up.RESULTS: Twenty-two members completed the survey, in 14 tertiary-care center departments representing 5 countries. The main consensual recommendations were: a precise otoscopic description of the quadrants involved, extensive audiological workup (bilateral tonal, vocal audiometry, and BERA), and a CT scan are required. Facial nerve monitoring and a combination of microscope and telescope are recommended for surgical removal. Clinical and audiological follow-up should be pursued yearly for at least 5 years. First MRI follow-up should be done at 18 months postoperatively if the removal violated the matrix. MRI follow-up duration depends on the initial extent of the cholesteatoma.CONCLUSION: The goal of preoperative and follow-up consensus from International Pediatric Otolaryngology Group participants is to help manage infants and children with congenital cholesteatoma. The operative techniques may vary, and experienced surgeons must perform these procedures.

  View details for DOI 10.1097/MAO.0000000000002521

  View details for PubMedID 31851066

• beta-Catenin is required for radial cell patterning and identity in the developing mouse cochlea. Proceedings of the National Academy of Sciences of the United States of America Jansson, L., Ebeid, M., Shen, J. W., Mokhtari, T. E., Quiruz, L. A., Ornitz, D. M., Huh, S., Cheng, A. G. 2019

  Abstract

  Development of multicellular organs requires the coordination of cell differentiation and patterning. Critical for sound detection, the mammalian organ of Corti contains functional units arranged tonotopically along the cochlear turns. Each unit consists of sensory hair cells intercalated by nonsensory supporting cells, both specified and radially patterned with exquisite precision during embryonic development. However, how cell identity and radial patterning are jointly controlled is poorly understood. Here we show that beta-catenin is required for specification of hair cell and supporting cell subtypes and radial patterning of the cochlea in vivo. In 2 mouse models of conditional beta-catenin deletion, early specification of Myosin7-expressing hair cells and Prox1-positive supporting cells was preserved. While beta-catenin-deficient cochleae expressed FGF8 and FGFR3, both of which are essential for pillar cell specification, the radial patterning of organ of Corti was disrupted, revealed by aberrant expression of cadherins and the pillar cell markers P75 and Lgr6. Moreover, beta-catenin ablation caused duplication of FGF8-positive inner hair cells and reduction of outer hair cells without affecting the overall hair cell density. In contrast, in another transgenic model with suppressed transcriptional activity of beta-catenin but preserved cell adhesion function, both specification and radial patterning of the organ of Corti were intact. Our study reveals specific functions of beta-catenin in governing cell identity and patterning mediated through cell adhesion in the developing cochlea.

  View details for DOI 10.1073/pnas.1910223116

  View details for PubMedID 31570588

• Atoh1 Directs Regeneration and Functional Recovery of the Mature Mouse Vestibular System. Cell reports Sayyid, Z. N., Wang, T., Chen, L., Jones, S. M., Cheng, A. G. 2019; 28 (2): 312

  Abstract

  Utricular hair cells (HCs) are mechanoreceptors required for vestibular function. After damage, regeneration of mammalian utricular HCs is limited and regenerated HCs appear immature. Thus, loss of vestibular function is presumed irreversible. Here, we found partial HC replacement and functional recovery in the mature mouse utricle, both enhanced by overexpressing the transcription factor Atoh1. Following damage, long-term fate mapping revealed that support cells non-mitotically and modestly regenerated HCs displaying no or immature bundles. By contrast, Atoh1 overexpression stimulated proliferation and widespread regeneration of HCs exhibiting elongated bundles, patent mechanotransduction channels, and synaptic connections. Finally, although damage without Atoh1 overexpression failed to initiate or sustain a spontaneous functional recovery, Atoh1 overexpression significantly enhanced both the degree and percentage of animals exhibiting sustained functional recovery. Therefore, the mature, damaged utricle has an Atoh1-responsive regenerative program leading to functional recovery, underscoring the potential of a reprogramming approach to sensory regeneration.

  View details for DOI 10.1016/j.celrep.2019.06.028

  View details for PubMedID 31291569

• Uncoordinated maturation of developing and regenerating postnatal mammalian vestibular hair cells. PLoS biology Wang, T. n., Niwa, M. n., Sayyid, Z. N., Hosseini, D. K., Pham, N. n., Jones, S. M., Ricci, A. J., Cheng, A. G. 2019; 17 (7): e3000326

  Abstract

  Sensory hair cells are mechanoreceptors required for hearing and balance functions. From embryonic development, hair cells acquire apical stereociliary bundles for mechanosensation, basolateral ion channels that shape receptor potential, and synaptic contacts for conveying information centrally. These key maturation steps are sequential and presumed coupled; however, whether hair cells emerging postnatally mature similarly is unknown. Here, we show that in vivo postnatally generated and regenerated hair cells in the utricle, a vestibular organ detecting linear acceleration, acquired some mature somatic features but hair bundles appeared nonfunctional and short. The utricle consists of two hair cell subtypes with distinct morphological, electrophysiological and synaptic features. In both the undamaged and damaged utricle, fate-mapping and electrophysiology experiments showed that Plp1+ supporting cells took on type II hair cell properties based on molecular markers, basolateral conductances and synaptic properties yet stereociliary bundles were absent, or small and nonfunctional. By contrast, Lgr5+ supporting cells regenerated hair cells with type I and II properties, representing a distinct hair cell precursor subtype. Lastly, direct physiological measurements showed that utricular function abolished by damage was partially regained during regeneration. Together, our data reveal a previously unrecognized aberrant maturation program for hair cells generated and regenerated postnatally and may have broad implications for inner ear regenerative therapies.

  View details for DOI 10.1371/journal.pbio.3000326

  View details for PubMedID 31260439

• Direct cellular reprogramming and inner ear regeneration. Expert opinion on biological therapy Atkinson, P. J., Kim, G. S., Cheng, A. G. 2018

  Abstract

  INTRODUCTION: Sound is integral to communication and connects us to the world through speech and music. Cochlear hair cells are essential for converting sounds into neural impulses. However, these cells are highly susceptible to damage from an array of factors, resulting in degeneration and ultimately irreversible hearing loss in humans. Since the discovery of hair cell regeneration in birds, there have been tremendous efforts to identify therapies that could promote hair cell regeneration in mammals. Areas covered: Here, we will review recent studies describing spontaneous hair cell regeneration and direct cellular reprograming as well as other factors that mediate mammalian hair cell regeneration. Expert opinion: Numerous combinatorial approaches have successfully reprogrammed non-sensory supporting cells to form hair cells, albeit with limited efficacy and maturation. Studies on epigenetic regulation and transcriptional network of hair cell progenitors may accelerate discovery of more promising reprogramming regimens.

  View details for PubMedID 30584811

• Aminoglycoside ribosome interactions reveal novel conformational states at ambient temperature NUCLEIC ACIDS RESEARCH O'Sullivan, M. E., Poitevin, F., Sierra, R. G., Gati, C., Dao, E., Rao, Y., Aksit, F., Ciftci, H., Corsepius, N., Greenhouse, R., Hayes, B., Hunter, M. S., Liang, M., McGurk, A., Mbgam, P., Obrinsky, T., Pardo-Avila, F., Seaberg, M. H., Cheng, A. G., Ricci, A. J., DeMirci, H. 2018; 46 (18): 9793–9804

  View details for DOI 10.1093/nar/gky693

  View details for Web of Science ID 000450953200048

• Aminoglycoside ribosome interactions reveal novel conformational states at ambient temperature. Nucleic acids research O'Sullivan, M. E., Poitevin, F., Sierra, R. G., Gati, C., Dao, E. H., Rao, Y., Aksit, F., Ciftci, H., Corsepius, N., Greenhouse, R., Hayes, B., Hunter, M. S., Liang, M., McGurk, A., Mbgam, P., Obrinsky, T., Pardo-Avila, F., Seaberg, M. H., Cheng, A. G., Ricci, A. J., DeMirci, H. 2018

  Abstract

  The bacterial 30S ribosomal subunit is a primary antibiotic target. Despite decades of discovery, the mechanisms by which antibiotic binding induces ribosomal dysfunction are not fully understood. Ambient temperature crystallographic techniques allow more biologically relevant investigation of how local antibiotic binding site interactions trigger global subunit rearrangements that perturb protein synthesis. Here, the structural effects of 2-deoxystreptamine (paromomycin and sisomicin), a novel sisomicin derivative, N1-methyl sulfonyl sisomicin (N1MS) and the non-deoxystreptamine (streptomycin) aminoglycosides on the ribosome at ambient and cryogenic temperatures were examined. Comparative studies led to three main observations. First, individual aminoglycoside-ribosome interactions in the decoding center were similar for cryogenic versus ambient temperature structures. Second, analysis of a highly conserved GGAA tetraloop of h45 revealed aminoglycoside-specific conformational changes, which are affected by temperature only for N1MS. We report the h44-h45 interface in varying states, i.e. engaged, disengaged and in equilibrium. Third, we observe aminoglycoside-induced effects on 30S domain closure, including a novel intermediary closure state, which is also sensitive to temperature. Analysis of three ambient and five cryogenic crystallography datasets reveal a correlation between h44-h45 engagement and domain closure. These observations illustrate the role of ambient temperature crystallography in identifying dynamic mechanisms of ribosomal dysfunction induced by local drug-binding site interactions. Together, these data identify tertiary ribosomal structural changes induced by aminoglycoside binding that provides functional insight and targets for drug design.

  View details for PubMedID 30113694

• Molecular therapy for genetic and degenerative vestibular disorders. Current opinion in otolaryngology & head and neck surgery Sayyid, Z. N., Kim, G. S., Cheng, A. G. 2018

  Abstract

  PURPOSE OF REVIEW: The primary purpose of this review is to summarize current literature in the field of vestibular regeneration with a focus on recent developments in molecular and gene therapies.RECENT FINDINGS: Since the discovery of limited vestibular hair cell regeneration in mammals in the 1990s, many elegant studies have improved our knowledge of mechanisms of development and regeneration of the vestibular system. A better understanding of the developmental pathways of the vestibular organs has fueled various biological strategies to enhance regeneration, including novel techniques in deriving vestibular hair cells from embryonic and induced pluripotent stem cells. In addition, the identification of specific genetic mutations responsible for vestibular disorders has opened various opportunities for gene replacement therapy.SUMMARY: Vestibular dysfunction is a significant clinical problem with limited therapeutic options, warranting research on biological strategies to repair/regenerate the vestibular organs to restore function. The use of gene therapy appears promising in animal models of vestibular dysfunction.

  View details for DOI 10.1097/MOO.0000000000000477

  View details for PubMedID 30045104

• Sox2 haploinsufficiency primes regeneration and Wnt responsiveness in the mouse cochlea JOURNAL OF CLINICAL INVESTIGATION Atkinson, P. J., Dong, Y., Gu, S., Liu, W., Najarro, E., Udagawa, T., Cheng, A. G. 2018; 128 (4): 1641–56

  Abstract

  During development, Sox2 is indispensable for cell division and differentiation, yet its roles in regenerating tissues are less clear. Here, we used combinations of transgenic mouse models to reveal that Sox2 haploinsufficiency (Sox2haplo) increases rather than impairs cochlear regeneration in vivo. Sox2haplo cochleae had delayed terminal mitosis and ectopic sensory cells, yet normal auditory function. Sox2haplo amplified and expanded domains of damage-induced Atoh1+ transitional cell formation in neonatal cochlea. Wnt activation via β-catenin stabilization (β-cateninGOF) alone failed to induce proliferation or transitional cell formation. By contrast, β-cateninGOF caused proliferation when either Sox2haplo or damage was present, and transitional cell formation when both were present in neonatal, but not mature, cochlea. Mechanistically, Sox2haplo or damaged neonatal cochleae showed lower levels of Sox2 and Hes5, but not of Wnt target genes. Together, our study unveils an interplay between Sox2 and damage in directing tissue regeneration and Wnt responsiveness and thus provides a foundation for potential combinatorial therapies aimed at stimulating mammalian cochlear regeneration to reverse hearing loss in humans.

  View details for PubMedID 29553487

  View details for PubMedCentralID PMC5873847

• Mind Your Ears: A New Antidote to Aminoglycoside Toxicity? JOURNAL OF MEDICINAL CHEMISTRY O'Sullivan, M. E., Cheng, A. G. 2018; 61 (1): 81–83

  Abstract

  Aminoglycoside antibiotics are known toxins to cochlear hair cells, causing permanent hearing loss. Using the zebrafish lateral line system as a platform for drug screen and subsequent validation in the rat cochlea in vivo, Chowdhury et al. characterized a novel otoprotectant working against aminoglycoside-induced hearing loss.

  View details for PubMedID 29256598

• Basilar Membrane Vibration After Targeted Removal of the Third Row of OHCs and Deiters Cells Xia, A., Udagawa, T., Raphael, P. D., Cheng, A. G., Steele, C. R., Applegate, B. E., Oghalai, J. S., Bergevin, C., Puria, S. AMER INST PHYSICS. 2018

  View details for DOI 10.1063/1.5038451

  View details for Web of Science ID 000461049900004

• Towards the Prevention of Aminoglycoside-Related Hearing Loss. Frontiers in cellular neuroscience O'Sullivan, M. E., Perez, A., Lin, R., Sajjadi, A., Ricci, A. J., Cheng, A. G. 2017; 11: 325

  Abstract

  Aminoglycosides are potent antibiotics deployed worldwide despite their known side-effect of sensorineural hearing loss. The main etiology of this sensory deficit is death of inner ear sensory hair cells selectively triggered by aminoglycosides. For decades, research has sought to unravel the molecular events mediating sensory cell demise, emphasizing the roles of reactive oxygen species and their potentials as therapeutic targets. Studies in recent years have revealed candidate transport pathways including the mechanotransducer channel for drug entry into sensory cells. Once inside sensory cells, intracellular targets of aminoglycosides, such as the mitochondrial ribosomes, are beginning to be elucidated. Based on these results, less ototoxic aminoglycoside analogs are being generated and may serve as alternate antimicrobial agents. In this article, we review the latest findings on mechanisms of aminoglycoside entry into hair cells, their intracellular actions and potential therapeutic targets for preventing aminoglycoside ototoxicity.

  View details for DOI 10.3389/fncel.2017.00325

  View details for PubMedID 29093664

  View details for PubMedCentralID PMC5651232

• Towards the Prevention of Aminoglycoside-Related Hearing Loss Frontiers in Cellular Neuroscience O'Sullivan, M. E., Perez, A., Lin, R., Ricci, A. J., Cheng, A. G. 2017; 11: 325

  Abstract

  Aminoglycosides are potent antibiotics deployed worldwide despite their known side-effect of sensorineural hearing loss. The main etiology of this sensory deficit is death of inner ear sensory hair cells selectively triggered by aminoglycosides. For decades, research has sought to unravel the molecular events mediating sensory cell demise, emphasizing the roles of reactive oxygen species and their potentials as therapeutic targets. Studies in recent years have revealed candidate transport pathways including the mechanotransducer channel for drug entry into sensory cells. Once inside sensory cells, intracellular targets of aminoglycosides, such as the mitochondrial ribosomes, are beginning to be elucidated. Based on these results, less ototoxic aminoglycoside analogs are being generated and may serve as alternate antimicrobial agents. In this article, we review the latest findings on mechanisms of aminoglycoside entry into hair cells, their intracellular actions and potential therapeutic targets for preventing aminoglycoside ototoxicity.

  View details for DOI 10.3389/fncel.2017.00325

  View details for PubMedCentralID PMC5651232

• Profiling Specific Inner Ear Cell Types Using Cell Sorting Techniques. Methods in molecular biology (Clifton, N.J.) Jan, T. A., Jansson, L., Atkinson, P. J., Wang, T., Cheng, A. G. 2016; 1427: 431-445

  Abstract

  Studies of specific tissue cell types are becoming increasingly important in advancing our understanding of cell biology and gene and protein expression. Prospective isolation of specific cell types is a powerful technique as it facilitates such investigations, allowing for analysis and characterization of individual cell populations. Such an approach to studying inner ear tissues presents a unique challenge because of the paucity of cells of interest and limited cell markers. In this chapter, we describe methods for selectively labeling and isolating different inner ear cell types from the neonatal mouse cochlea using fluorescence-activated cell sorting.

  View details for DOI 10.1007/978-1-4939-3615-1_23

  View details for PubMedID 27259940

• Intraoperative acupuncture for posttonsillectomy pain: A randomized, double-blind, placebo-controlled trial LARYNGOSCOPE Tsao, G. J., Messner, A. H., Seybold, J., Sayyid, Z. N., Cheng, A. G., Golianu, B. 2015; 125 (8): 1972-1978

  Abstract

  To evaluate the effect of intraoperative acupuncture on posttonsillectomy pain in the pediatric population.Prospective, double-blind, randomized, placebo-controlled trial.Patients aged 3 to 12 years undergoing tonsillectomy were recruited at a tertiary children's hospital between February 2011 and May 2012. Participants were block-randomized to receive acupuncture or sham acupuncture during anesthesia for tonsillectomy. Surgeons, staff, and parents were blinded from treatment. Tonsillectomy was performed by one of two surgeons using a standard technique (monopolar cautery), and a single anesthetic protocol was followed. Study endpoints included time spent in the postanesthesia care unit, the amount of opioids administered in the perioperative period, and pain measures and presence of nausea/vomiting from postoperative home surveys.Fifty-nine children aged 3 to 12 years were randomized to receive acupuncture (n = 30) or sham acupuncture (n = 29). No significant demographic differences were noted between the two cohorts. Perioperative data were recorded for all patients; 73% of patients later returned home surveys. There were no significant differences in the amount of opioid medications administered or total postanesthesia care unit time between the two cohorts. Home surveys of patients but not of parents revealed significant improvements in pain control in the acupuncture treatment-group postoperatively (P = 0.0065 and 0.051, respectively), and oral intake improved significantly earlier in the acupuncture treatment group (P = 0.01). No adverse effects of acupuncture were reported.This study demonstrates that intraoperative acupuncture is feasible, well tolerated, and results in improved pain and earlier return of diet postoperatively.1b. Laryngoscope, 2015.

  View details for DOI 10.1002/lary.25252

  View details for Web of Science ID 000358379700048

• Sensory hair cell development and regeneration: similarities and differences DEVELOPMENT Atkinson, P. J., Najarro, E. H., Sayyid, Z. N., Cheng, A. G. 2015; 142 (9): 1561-1571

  Abstract

  Sensory hair cells are mechanoreceptors of the auditory and vestibular systems and are crucial for hearing and balance. In adult mammals, auditory hair cells are unable to regenerate, and damage to these cells results in permanent hearing loss. By contrast, hair cells in the chick cochlea and the zebrafish lateral line are able to regenerate, prompting studies into the signaling pathways, morphogen gradients and transcription factors that regulate hair cell development and regeneration in various species. Here, we review these findings and discuss how various signaling pathways and factors function to modulate sensory hair cell development and regeneration. By comparing and contrasting development and regeneration, we also highlight the utility and limitations of using defined developmental cues to drive mammalian hair cell regeneration.

  View details for DOI 10.1242/dev.114926

  View details for Web of Science ID 000353591300002

  View details for PubMedID 25922522

  View details for PubMedCentralID PMC4419275

• Intraoperative acupuncture for posttonsillectomy pain: A randomized, double-blind, placebo-controlled trial. The Laryngoscope Tsao, G. J., Messner, A. H., Seybold, J., Sayyid, Z. N., Cheng, A. G., Golianu, B. 2015

  Abstract

  To evaluate the effect of intraoperative acupuncture on posttonsillectomy pain in the pediatric population.Prospective, double-blind, randomized, placebo-controlled trial.Patients aged 3 to 12 years undergoing tonsillectomy were recruited at a tertiary children's hospital between February 2011 and May 2012. Participants were block-randomized to receive acupuncture or sham acupuncture during anesthesia for tonsillectomy. Surgeons, staff, and parents were blinded from treatment. Tonsillectomy was performed by one of two surgeons using a standard technique (monopolar cautery), and a single anesthetic protocol was followed. Study endpoints included time spent in the postanesthesia care unit, the amount of opioids administered in the perioperative period, and pain measures and presence of nausea/vomiting from postoperative home surveys.Fifty-nine children aged 3 to 12 years were randomized to receive acupuncture (n = 30) or sham acupuncture (n = 29). No significant demographic differences were noted between the two cohorts. Perioperative data were recorded for all patients; 73% of patients later returned home surveys. There were no significant differences in the amount of opioid medications administered or total postanesthesia care unit time between the two cohorts. Home surveys of patients but not of parents revealed significant improvements in pain control in the acupuncture treatment-group postoperatively (P = 0.0065 and 0.051, respectively), and oral intake improved significantly earlier in the acupuncture treatment group (P = 0.01). No adverse effects of acupuncture were reported.This study demonstrates that intraoperative acupuncture is feasible, well tolerated, and results in improved pain and earlier return of diet postoperatively.1b. Laryngoscope, 2015.

  View details for DOI 10.1002/lary.25252

  View details for PubMedID 25851423

• Making sense of Wnt signaling-linking hair cell regeneration to development FRONTIERS IN CELLULAR NEUROSCIENCE Jansson, L., Kim, G. S., Cheng, A. G. 2015; 9

  Abstract

  Wnt signaling is a highly conserved pathway crucial for development and homeostasis of multicellular organisms. Secreted Wnt ligands bind Frizzled receptors to regulate diverse processes such as axis patterning, cell division, and cell fate specification. They also serve to govern self-renewal of somatic stem cells in several adult tissues. The complexity of the pathway can be attributed to the myriad of Wnt and Frizzled combinations as well as its diverse context-dependent functions. In the developing mouse inner ear, Wnt signaling plays diverse roles, including specification of the otic placode and patterning of the otic vesicle. At later stages, its activity governs sensory hair cell specification, cell cycle regulation, and hair cell orientation. In regenerating sensory organs from non-mammalian species, Wnt signaling can also regulate the extent of proliferative hair cell regeneration. This review describes the current knowledge of the roles of Wnt signaling and Wnt-responsive cells in hair cell development and regeneration. We also discuss possible future directions and the potential application and limitation of Wnt signaling in augmenting hair cell regeneration.

  View details for DOI 10.3389/fncel.2015.00066

  View details for Web of Science ID 000352399400001

  View details for PubMedID 25814927

  View details for PubMedCentralID PMC4356074

• Protein-engineered hydrogel encapsulation for 3-d culture of murine cochlea. Otology & neurotology Chang, D. T., Chai, R., DiMarco, R., Heilshorn, S. C., Cheng, A. G. 2015; 36 (3): 531-538

  Abstract

  Elastin-like protein (ELP) hydrogel helps maintain the three-dimensional (3-D) cochlear structure in culture.Whole-organ culture of the cochlea is a useful model system facilitating manipulation and analysis of live sensory cells and surrounding nonsensory cells. The precisely organized 3-D cochlear structure demands a culture method that preserves this delicate architecture; however, current methods have not been optimized to serve such a purpose.A protein-engineered ELP hydrogel was used to encapsulate organ of Corti isolated from neonatal mice. Cultured cochleae were immunostained for markers of hair cells and supporting cells. Organ of Corti hair cell and supporting cell density and organ dimensions were compared between the ELP and nonencapsulated systems. These culture systems were then compared with noncultured cochlea.After 3 days in vitro, vital dye uptake and immunostaining for sensory and nonsensory cells show that encapsulated cochlea contain viable cells with an organized architecture. In comparison with nonencapsulated cultured cochlea, ELP-encapsulated cochleae exhibit higher densities of hair cells and supporting cells and taller and narrower organ of Corti dimensions that more closely resemble those of noncultured cochleae. However, we found compromised cell viability when the culture period extended beyond 3 days.We conclude that the ELP hydrogel can help preserve the 3-D architecture of neonatal cochlea in short-term culture, which may be applicable to in vitro study of the physiology and pathophysiology of the inner ear.

  View details for DOI 10.1097/MAO.0000000000000518

  View details for PubMedID 25111520

• Designer aminoglycosides prevent cochlear hair cell loss and hearing loss. journal of clinical investigation Huth, M. E., Han, K., Sotoudeh, K., Hsieh, Y., Effertz, T., Vu, A. A., Verhoeven, S., Hsieh, M. H., Greenhouse, R., Cheng, A. G., Ricci, A. J. 2015; 125 (2): 583-592

  Abstract

  Bacterial infections represent a rapidly growing challenge to human health. Aminoglycosides are widely used broad-spectrum antibiotics, but they inflict permanent hearing loss in up to ~50% of patients by causing selective sensory hair cell loss. Here, we hypothesized that reducing aminoglycoside entry into hair cells via mechanotransducer channels would reduce ototoxicity, and therefore we synthesized 9 aminoglycosides with modifications based on biophysical properties of the hair cell mechanotransducer channel and interactions between aminoglycosides and the bacterial ribosome. Compared with the parent aminoglycoside sisomicin, all 9 derivatives displayed no or reduced ototoxicity, with the lead compound N1MS 17 times less ototoxic and with reduced penetration of hair cell mechanotransducer channels in rat cochlear cultures. Both N1MS and sisomicin suppressed growth of E. coli and K. pneumoniae, with N1MS exhibiting superior activity against extended spectrum β lactamase producers, despite diminished activity against P. aeruginosa and S. aureus. Moreover, systemic sisomicin treatment of mice resulted in 75% to 85% hair cell loss and profound hearing loss, whereas N1MS treatment preserved both hair cells and hearing. Finally, in mice with E. coli-infected bladders, systemic N1MS treatment eliminated bacteria from urinary tract tissues and serially collected urine samples, without compromising auditory and kidney functions. Together, our findings establish N1MS as a nonototoxic aminoglycoside and support targeted modification as a promising approach to generating nonototoxic antibiotics.

  View details for DOI 10.1172/JCI77424

  View details for PubMedID 25555219

• Lgr5+ cells regenerate hair cells via proliferation and direct transdifferentiation in damaged neonatal mouse utricle. Nature communications Wang, T., Chai, R., Kim, G. S., Pham, N., Jansson, L., Nguyen, D., Kuo, B., May, L. A., Zuo, J., Cunningham, L. L., Cheng, A. G. 2015; 6: 6613-?

  Abstract

  Recruitment of endogenous progenitors is critical during tissue repair. The inner ear utricle requires mechanosensory hair cells (HCs) to detect linear acceleration. After damage, non-mammalian utricles regenerate HCs via both proliferation and direct transdifferentiation. In adult mammals, limited transdifferentiation from unidentified progenitors occurs to regenerate extrastriolar Type II HCs. Here we show that HC damage in neonatal mouse utricle activates the Wnt target gene Lgr5 in striolar supporting cells. Lineage tracing and time-lapse microscopy reveal that Lgr5+ cells transdifferentiate into HC-like cells in vitro. In contrast to adults, HC ablation in neonatal utricles in vivo recruits Lgr5+ cells to regenerate striolar HCs through mitotic and transdifferentiation pathways. Both Type I and II HCs are regenerated, and regenerated HCs display stereocilia and synapses. Lastly, stabilized ß-catenin in Lgr5+ cells enhances mitotic activity and HC regeneration. Thus Lgr5 marks Wnt-regulated, damage-activated HC progenitors and may help uncover factors driving mammalian HC regeneration.

  View details for DOI 10.1038/ncomms7613

  View details for PubMedID 25849379

  View details for PubMedCentralID PMC4391285

• Spontaneous hair cell regeneration in the neonatal mouse cochlea in vivo (vol 141, pg 816, 2014) DEVELOPMENT Cox, B. C., Chai, R., Lenoir, A., Liu, Z., Zhang, L., Duc-Huy Nguyen, Chalasani, K., Steigelman, K. A., Fang, J., Rubel, E. W., Cheng, A. G., Zuo, J. 2014; 141 (7): 1599

  View details for DOI 10.1242/dev.109421

  View details for Web of Science ID 000333184500019

• Spontaneous hair cell regeneration in the neonatal mouse cochlea in vivo DEVELOPMENT Cox, B. C., Chai, R., Lenoir, A., Liu, Z., Zhang, L., Nguyen, D., Chalasani, K., Steigelman, K. A., Fang, J., Cheng, A. G., Zuo, J. 2014; 141 (4): 816-829

  Abstract

  Loss of cochlear hair cells in mammals is currently believed to be permanent, resulting in hearing impairment that affects more than 10% of the population. Here, we developed two genetic strategies to ablate neonatal mouse cochlear hair cells in vivo. Both Pou4f3(DTR/+) and Atoh1-CreER™; ROSA26(DTA/+) alleles allowed selective and inducible hair cell ablation. After hair cell loss was induced at birth, we observed spontaneous regeneration of hair cells. Fate-mapping experiments demonstrated that neighboring supporting cells acquired a hair cell fate, which increased in a basal to apical gradient, averaging over 120 regenerated hair cells per cochlea. The normally mitotically quiescent supporting cells proliferated after hair cell ablation. Concurrent fate mapping and labeling with mitotic tracers showed that regenerated hair cells were derived by both mitotic regeneration and direct transdifferentiation. Over time, regenerated hair cells followed a similar pattern of maturation to normal hair cell development, including the expression of prestin, a terminal differentiation marker of outer hair cells, although many new hair cells eventually died. Hair cell regeneration did not occur when ablation was induced at one week of age. Our findings demonstrate that the neonatal mouse cochlea is capable of spontaneous hair cell regeneration after damage in vivo. Thus, future studies on the neonatal cochlea might shed light on the competence of supporting cells to regenerate hair cells and on the factors that promote the survival of newly regenerated hair cells.

  View details for DOI 10.1242/dev.103036

  View details for Web of Science ID 000331460900009

  View details for PubMedID 24496619

  View details for PubMedCentralID PMC3912828

• Transient, afferent input-dependent, postnatal niche for neural progenitor cells in the cochlear nucleus (vol 110, pg 14456, 2013) PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA Volkenstein, S., Oshima, K., Sinkkonen, S. T., Corrales, C., Most, S. P., Chai, R., Jan, T. A., van Amerongen, R., Cheng, A. G., Heller, S. 2013; 110 (42): 17160

  View details for DOI 10.1073/pnas.1317787110

  View details for Web of Science ID 000325634200095

• Transient, afferent input-dependent, postnatal niche for neural progenitor cells in the cochlear nucleus. Proceedings of the National Academy of Sciences of the United States of America Volkenstein, S., Oshima, K., Sinkkonen, S. T., Corrales, C. E., Most, S. P., Chai, R., Jan, T. A., Cheng, A. G., Heller, S. 2013; 110 (35): 14456-14461

  Abstract

  In the cochlear nucleus (CN), the first central relay of the auditory pathway, the survival of neurons during the first weeks after birth depends on afferent innervation from the cochlea. Although input-dependent neuron survival has been extensively studied in the CN, neurogenesis has not been evaluated as a possible mechanism of postnatal plasticity. Here we show that new neurons are born in the CN during the critical period of postnatal plasticity. Coincidently, we found a population of neural progenitor cells that are controlled by a complex interplay of Wnt, Notch, and TGFβ/BMP signaling, in which low levels of TGFβ/BMP signaling are permissive for progenitor proliferation that is promoted by Wnt and Notch activation. We further show that cells with activated Wnt signaling reside in the CN and that these cells have high propensity for neurosphere formation. Cochlear ablation resulted in diminishment of progenitors and Wnt/β-catenin-active cells, suggesting that the neonatal CN maintains an afferent innervation-dependent population of progenitor cells that display active canonical Wnt signaling.

  View details for DOI 10.1073/pnas.1307376110

  View details for PubMedID 23940359

• Tympanic border cells are Wnt-responsive and can act as progenitors for postnatal mouse cochlear cells DEVELOPMENT Jan, T. A., Chai, R., Sayyid, Z. N., van Amerongen, R., Xia, A., Wang, T., Sinkkonen, S. T., Zeng, Y. A., Levin, J. R., Heller, S., Nusse, R., Cheng, A. G. 2013; 140 (6): 1196-1206

  Abstract

  Permanent hearing loss is caused by the irreversible damage of cochlear sensory hair cells and nonsensory supporting cells. In the postnatal cochlea, the sensory epithelium is terminally differentiated, whereas tympanic border cells (TBCs) beneath the sensory epithelium are proliferative. The functions of TBCs are poorly characterized. Using an Axin2(lacZ) Wnt reporter mouse, we found transient but robust Wnt signaling and proliferation in TBCs during the first 3 postnatal weeks, when the number of TBCs decreases. In vivo lineage tracing shows that a subset of hair cells and supporting cells is derived postnatally from Axin2-expressing TBCs. In cochlear explants, Wnt agonists stimulated the proliferation of TBCs, whereas Wnt inhibitors suppressed it. In addition, purified Axin2(lacZ) cells were clonogenic and self-renewing in culture in a Wnt-dependent manner, and were able to differentiate into hair cell-like and supporting cell-like cells. Taken together, our data indicate that Axin2-positive TBCs are Wnt responsive and can act as precursors to sensory epithelial cells in the postnatal cochlea.

  View details for DOI 10.1242/dev.087528

  View details for Web of Science ID 000315445800006

  View details for PubMedID 23444352

  View details for PubMedCentralID PMC3585657

• Integrity and Regeneration of Mechanotransduction Machinery Regulate Aminoglycoside Entry and Sensory Cell Death PLOS ONE Vu, A. A., Nadaraja, G. S., Huth, M. E., Luk, L., Kim, J., Chai, R., Ricci, A. J., Cheng, A. G. 2013; 8 (1)

  Abstract

  Sound perception requires functional hair cell mechanotransduction (MET) machinery, including the MET channels and tip-link proteins. Prior work showed that uptake of ototoxic aminoglycosides (AG) into hair cells requires functional MET channels. In this study, we examined whether tip-link proteins, including Cadherin 23 (Cdh23), regulate AG entry into hair cells. Using time-lapse microscopy on cochlear explants, we found rapid uptake of gentamicin-conjugated Texas Red (GTTR) into hair cells from three-day-old Cdh23(+/+) and Cdh23(v2J/+) mice, but failed to detect GTTR uptake in Cdh23(v2J/v2J) hair cells. Pre-treatment of wildtype cochleae with the calcium chelator 1,2-bis(o-aminophenoxy) ethane-N,N,N',N'-tetraacetic acid (BAPTA) to disrupt tip-links also effectively reduced GTTR uptake into hair cells. Both Cdh23(v2J/v2J) and BAPTA-treated hair cells were protected from degeneration caused by gentamicin. Six hours after BAPTA treatment, GTTR uptake remained reduced in comparison to controls; by 24 hours, drug uptake was comparable between untreated and BAPTA-treated hair cells, which again became susceptible to cell death induced by gentamicin. Together, these results provide genetic and pharmacologic evidence that tip-links are required for AG uptake and toxicity in hair cells. Because tip-links can spontaneously regenerate, their temporary breakage offers a limited time window when hair cells are protected from AG toxicity.

  View details for DOI 10.1371/journal.pone.0054794

  View details for Web of Science ID 000314023600111

  View details for PubMedID 23359017

  View details for PubMedCentralID PMC3554584

• A simple method for purification of vestibular hair cells and non-sensory cells, and application for proteomic analysis. PloS one Herget, M., Scheibinger, M., Guo, Z., Jan, T. A., Adams, C. M., Cheng, A. G., Heller, S. 2013; 8 (6)

  Abstract

  Mechanosensitive hair cells and supporting cells comprise the sensory epithelia of the inner ear. The paucity of both cell types has hampered molecular and cell biological studies, which often require large quantities of purified cells. Here, we report a strategy allowing the enrichment of relatively pure populations of vestibular hair cells and non-sensory cells including supporting cells. We utilized specific uptake of fluorescent styryl dyes for labeling of hair cells. Enzymatic isolation and flow cytometry was used to generate pure populations of sensory hair cells and non-sensory cells. We applied mass spectrometry to perform a qualitative high-resolution analysis of the proteomic makeup of both the hair cell and non-sensory cell populations. Our conservative analysis identified more than 600 proteins with a false discovery rate of <3% at the protein level and <1% at the peptide level. Analysis of proteins exclusively detected in either population revealed 64 proteins that were specific to hair cells and 103 proteins that were only detectable in non-sensory cells. Statistical analyses extended these groups by 53 proteins that are strongly upregulated in hair cells versus non-sensory cells and vice versa by 68 proteins. Our results demonstrate that enzymatic dissociation of styryl dye-labeled sensory hair cells and non-sensory cells is a valid method to generate pure enough cell populations for flow cytometry and subsequent molecular analyses.

  View details for DOI 10.1371/journal.pone.0066026

  View details for PubMedID 23750277

  View details for PubMedCentralID PMC3672136

• Wnt signaling induces proliferation of sensory precursors in the postnatal mouse cochlea PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA Chai, R., Kuo, B., Wang, T., Liaw, E. J., Xia, A., Jan, T. A., Liu, Z., Taketo, M. M., Oghalai, J. S., Nusse, R., Zuo, J., Cheng, A. G. 2012; 109 (21): 8167-8172

  Abstract

  Inner ear hair cells are specialized sensory cells essential for auditory function. Previous studies have shown that the sensory epithelium is postmitotic, but it harbors cells that can behave as progenitor cells in vitro, including the ability to form new hair cells. Lgr5, a Wnt target gene, marks distinct supporting cell types in the neonatal cochlea. Here, we tested the hypothesis that Lgr5(+) cells are Wnt-responsive sensory precursor cells. In contrast to their quiescent in vivo behavior, Lgr5(+) cells isolated by flow cytometry from neonatal Lgr5(EGFP-CreERT2/+) mice proliferated and formed clonal colonies. After 10 d in culture, new sensory cells formed and displayed specific hair cell markers (myo7a, calretinin, parvalbumin, myo6) and stereocilia-like structures expressing F-actin and espin. In comparison with other supporting cells, Lgr5(+) cells were enriched precursors to myo7a(+) cells, most of which formed without mitotic division. Treatment with Wnt agonists increased proliferation and colony-formation capacity. Conversely, small-molecule inhibitors of Wnt signaling suppressed proliferation without compromising the myo7a(+) cells formed by direct differentiation. In vivo lineage tracing supported the idea that Lgr5(+) cells give rise to myo7a(+) hair cells in the neonatal Lgr5(EGFP-CreERT2/+) cochlea. In addition, overexpression of β-catenin initiated proliferation and led to transient expansion of Lgr5(+) cells within the cochlear sensory epithelium. These results suggest that Lgr5 marks sensory precursors and that Wnt signaling can promote their proliferation and provide mechanistic insights into Wnt-responsive progenitor cells during sensory organ development.

  View details for DOI 10.1073/pnas.1202774109

  View details for Web of Science ID 000304445800053

  View details for PubMedID 22562792

  View details for PubMedCentralID PMC3361451

• Isolating LacZ-expressing Cells from Mouse Inner Ear Tissues using Flow Cytometry JOVE-JOURNAL OF VISUALIZED EXPERIMENTS Jan, T. A., Chai, R., Sayyid, Z. N., Cheng, A. G. 2011

  Abstract

  Isolation of specific cell types allows one to analyze rare cell populations such as stem/progenitor cells. Such an approach to studying inner ear tissues presents a unique challenge because of the paucity of cells of interest and few transgenic reporter mouse models. Here, we describe a protocol using fluorescence-conjugated probes to selectively label LacZ-positive cells from the neonatal cochleae. The most common underlying pathology of sensorineural hearing loss is the irreversible damage and loss of cochlear sensory hair cells, which are required to transduce sound waves to neural impulses. Recent evidence suggests that the murine auditory and vestibular organs harbor stem/progenitor cells that may have regenerative potential. These findings warrant further investigation, including identifying specific cell types with stem/progenitor cell characteristics. The Wnt signaling pathway has been demonstrated to play a critical role in maintaining stem/progenitor cell populations in several organ systems. We have recently identified Wnt-responsive Axin2-expressing cells in the neonatal cochlea, but their function is largely unknown. To better understand the behavior of these Wnt-responsive cells in vitro, we have developed a method of isolating Axin2-expressing cells from cochleae of Axin2-LacZ reporter mice. Using flow cytometry to isolate Axin2-LacZ positive cells from the neonatal cochleae, we could in turn execute a variety of experiments on live cells to interrogate their behavior as stem/progenitor cells. Here, we describe in detail the steps for the microdissection of neonatal cochlea, dissociation of these tissues, labeling of the LacZ-positive cells using a fluorogenic substrate, and cell sorting. Techniques for dissociating cochleae into single cells and isolating cochlear cells via flow cytometry have been described. We have made modifications to these techniques to establish a novel protocol to isolate LacZ-expressing cells from the neonatal cochlea.

  View details for DOI 10.3791/3432

  View details for Web of Science ID 000209222300024

  View details for PubMedCentralID PMC3369666

• Dynamic Expression of Lgr5, a Wnt Target Gene, in the Developing and Mature Mouse Cochlea JARO-JOURNAL OF THE ASSOCIATION FOR RESEARCH IN OTOLARYNGOLOGY Chai, R., Xia, A., Wang, T., Jan, T. A., Hayashi, T., Bermingham-McDonogh, O., Cheng, A. G. 2011; 12 (4): 455-469

  Abstract

  The Wnt signaling pathway is a recurring theme in tissue development and homeostasis. Its specific roles during inner ear development are just emerging, but few studies have characterized Wnt target genes. Lgr5, a member of the G protein-coupled receptor family, is a Wnt target in the gastrointestinal and integumentary systems. Although its function is unknown, its deficiency leads to perinatal lethality due to gastrointestinal distension. In this study, we used a knock-in reporter mouse to examine the spatiotemporal expression of Lgr5 in the cochlear duct during embryonic and postnatal periods. In the embryonic day 15.5 (E15.5) cochlear duct, Lgr5-EGFP is expressed in the floor epithelium and overlapped with the prosensory markers Sox2, Jagged1, and p27(Kip1). Nascent hair cells and supporting cells in the apical turn of the E18.5 cochlear duct express Lgr5-EGFP, which becomes downregulated in hair cells and subsets of supporting cells in more mature stages. In situ hybridization experiments validated the reporter expression, which gradually decreases until the second postnatal week. Only the third row of Deiters' cells expresses Lgr5-EGFP in the mature organ of Corti. Normal cochlear development was observed in Lgr5(EGFP/EGFP) and Lgr5(EGFP/+) mice, which exhibited normal auditory thresholds. The expression pattern of Lgr5 contrasts with another Wnt target gene, Axin2, a feedback inhibitor of the Wnt pathway. Robust Axin2 expression was found in cells surrounding the embryonic cochlear duct and becomes restricted to tympanic border cells below the basilar membrane in the postnatal cochlea. Both Lgr5 and Axin2 act as Wnt targets in the cochlea because purified Wnt3a promoted and Wnt antagonist suppressed their expression. Their differential expression among cell populations highlights the dynamic but complex distribution of Wnt-activated cells in and around the embryonic and postnatal cochlea.

  View details for DOI 10.1007/s10162-011-0267-2

  View details for Web of Science ID 000292047900004

  View details for PubMedID 21472479

  View details for PubMedCentralID PMC3123443

• Functional Hair Cell Mechanotransducer Channels Are Required for Aminoglycoside Ototoxicity PLOS ONE Alharazneh, A., Luk, L., Huth, M., Monfared, A., Steyger, P. S., Cheng, A. G., Ricci, A. J. 2011; 6 (7)

  Abstract

  Aminoglycosides (AG) are commonly prescribed antibiotics with potent bactericidal activities. One main side effect is permanent sensorineural hearing loss, induced by selective inner ear sensory hair cell death. Much work has focused on AG's initiating cell death processes, however, fewer studies exist defining mechanisms of AG uptake by hair cells. The current study investigated two proposed mechanisms of AG transport in mammalian hair cells: mechanotransducer (MET) channels and endocytosis. To study these two mechanisms, rat cochlear explants were cultured as whole organs in gentamicin-containing media. Two-photon imaging of Texas Red conjugated gentamicin (GTTR) uptake into live hair cells was rapid and selective. Hypocalcemia, which increases the open probability of MET channels, increased AG entry into hair cells. Three blockers of MET channels (curare, quinine, and amiloride) significantly reduced GTTR uptake, whereas the endocytosis inhibitor concanavalin A did not. Dynosore quenched the fluorescence of GTTR and could not be tested. Pharmacologic blockade of MET channels with curare or quinine, but not concanavalin A or dynosore, prevented hair cell loss when challenged with gentamicin for up to 96 hours. Taken together, data indicate that the patency of MET channels mediated AG entry into hair cells and its toxicity. Results suggest that limiting permeation of AGs through MET channel or preventing their entry into endolymph are potential therapeutic targets for preventing hair cell death and hearing loss.

  View details for DOI 10.1371/journal.pone.0022347

  View details for Web of Science ID 000293175100021

  View details for PubMedID 21818312

  View details for PubMedCentralID PMC3144223

• Intrinsic regenerative potential of murine cochlear supporting cells Scientific Reports Sinkkonen ST, Chai R, Jan, T, Hartman B, Laske R, Gahlen F, Sinkkonen W, Cheng AG, Oshima K, Heller 2011; 1 (26): DOI:10.1038/srep0002
• Mechanisms of aminoglycoside ototoxicity and targets of hair cell protection. International journal of otolaryngology Huth, M. E., Ricci, A. J., Cheng, A. G. 2011; 2011: 937861-?

  Abstract

  Aminoglycosides are commonly prescribed antibiotics with deleterious side effects to the inner ear. Due to their popular application as a result of their potent antimicrobial activities, many efforts have been undertaken to prevent aminoglycoside ototoxicity. Over the years, understanding of the antimicrobial as well as ototoxic mechanisms of aminoglycosides has increased. These mechanisms are reviewed in regard to established and potential future targets of hair cell protection.

  View details for DOI 10.1155/2011/937861

  View details for PubMedID 22121370

  View details for PubMedCentralID PMC3202092

• Decompression of the Orbital Apex An Alternate Approach to Surgical Excision for Radiographically Benign Orbital Apex Tumors ARCHIVES OF OTOLARYNGOLOGY-HEAD & NECK SURGERY Almond, M. C., Cheng, A. G., Schiedler, V., Sires, B. S., Most, S. P., Jian-Amadi, A. 2009; 135 (10): 1015-1018

  Abstract

  To study the outcome of patients with orbital apex lesions treated with endoscopic decompression alone.Retrospective medical chart review with a mean follow-up of 25.6 months.Departments of Ophthalmology and Otolaryngology, University of Washington, Seattle.Five individuals seen at the University of Washington Medical Center from November 2003 through December 2005 with visual disturbance caused by orbital apex lesions as documented by preoperative magnetic resonance imaging or computed tomographic scan.All patients underwent endoscopic decompression of the medial wall of the orbital apex with incision of the periorbita.Postoperative visual acuity, presence or absence of a relative afferent pupillary defect, color vision, and visual field were recorded.All 5 patients presented with visual field deficits, 4 of whom improved postoperatively. Three patients had dyschromatopsia preoperatively, 2 of whom improved postoperatively. Visual acuity improved or stabilized in 4 of 5 patients postoperatively. One patient had progressive visual loss during the course of her follow-up, which, after obtaining postoperative imaging, was attributed to inadequate decompression of the apex at its most posterior aspect. This same patient also developed postoperative sinusitis that resolved with antibiotic treatment. Two patients developed diplopia, 1 in primary gaze requiring treatment with prismatic lenses. All patients presented with and maintained normal intraocular pressures.Orbital apex lesions can often be effectively and relatively safely treated by endoscopic decompression alone.

  View details for Web of Science ID 000270777800010

  View details for PubMedID 19841341

• Sensorineural hearing loss in patients with cystic fibrosis OTOLARYNGOLOGY-HEAD AND NECK SURGERY Cheng, A. G., Johnston, P. R., Luz, J., Uluer, A., Fligor, B., Licameli, G. R., Kenna, M. A., Jones, D. T. 2009; 141 (1): 86-90

  Abstract

  To determine the prevalence of sensorineural hearing loss (SNHL) in cystic fibrosis (CF) patients and its relationship to antibiotic use.Case series with chart review.Tertiary care pediatric hospital.We reviewed the medical records of CF patients seen in our children's hospital between March 1994 and December 2007. Data collected included patient demographics, audiograms, tympanograms, genotype, and use of potentially ototoxic antibiotics.Seven of 50 (14%) patients had SNHL. Three percent of patients who received 10 courses (P<0.01). No patients who received five or fewer courses of nasal irrigation with aminoglycosides had SNHL versus 23 percent of those who received more than five courses (P<0.05). Nine percent of patients who received five or fewer courses of macrolides had SNHL versus 60 percent of those who received more than five courses (P=0.079).CF patients receiving aminoglycosides are at high risk for developing SNHL.

  View details for DOI 10.1016/j.otohns.2009.03.020

  View details for Web of Science ID 000267404900019

  View details for PubMedID 19559964

• Airway management in Nager Syndrome LARYNGOSCOPE Ho, A. S., Aleshi, P., Cohen, S. E., Koltai, P. J., Cheng, A. G. 2009; 119: S179-S179

  View details for DOI 10.1002/lary.20468

  View details for Web of Science ID 000207862500179

• Airway management in Nager Syndrome INTERNATIONAL JOURNAL OF PEDIATRIC OTORHINOLARYNGOLOGY Ho, A. S., Aleshi, P., Cohen, S. E., Koltai, P. J., Cheng, A. G. 2008; 72 (12): 1885-1888

  Abstract

  Nager acrofacial dysostosis is a rare congenital syndrome characterized by malformed mandibulofacial structures and pre-axial upper limbs. Trismus and glossoptosis from mandibular abnormalities predisposes infants to life-threatening respiratory distress. A case of a Nager Syndrome mother delivering a similarly afflicted fetus is presented, with approaches to maintaining both tenuous airways described. Distinguishing this condition from similar syndromes is critical for care and prognosis.

  View details for DOI 10.1016/j.ijporl.2008.09.007

  View details for PubMedID 18947886

• Melanoacanthoma of the external auditory canal: a case report and review of the literature AMERICAN JOURNAL OF OTOLARYNGOLOGY Cheng, A. G., Deubner, H., Whipple, M. E. 2007; 28 (6): 433-435

  View details for DOI 10.1016/j.amjoto.2006.11.006

  View details for Web of Science ID 000251068600016

  View details for PubMedID 17980780

• Cerebrospinal fluid leak in the neck: A rare complication of glomus vagale excision OTOLARYNGOLOGY-HEAD AND NECK SURGERY Cheng, A. G., Maronian, N. C., Futran, N. D. 2006; 134 (2): 334-335

  View details for DOI 10.1016/j.otohns.2005.07.032

  View details for Web of Science ID 000235293600027

  View details for PubMedID 16455388

• Mechanisms of hair cell death and protection. Current opinion in otolaryngology & head and neck surgery Cheng, A. G., Cunningham, L. L., Rubel, E. W. 2005; 13 (6): 343-348

  Abstract

  Sensory hair cells are mechanotransducers of the inner ear that are essential for hearing and balance. Hair cell death commonly occurs following acoustic trauma or exposure to ototoxins, such as the aminoglycoside antibiotics and the antineoplastic agent cisplatin. Loss of these inner ear sensory cells can lead to permanent sensorineural hearing loss, balance disturbance, or both. Currently, the only effective clinical intervention is prevention from exposure to known ototoxic insults. To help improve therapeutic strategies, a better understanding of the molecular mechanisms underlying hair cell degeneration is required. Current knowledge of these cell death mechanisms and potential therapeutic targets are discussed in this review.Studies have shown that caspase-9 and caspase-3 are key mediators of hair cell death induced by noise, aminoglycosides, and cisplatin. The Bcl-2 family consists of a group of proapoptotic and antiapoptotic molecules that act upstream of and regulate caspase activation. Recent studies have shed light on the roles of molecules acting more upstream, including mitogen-activated protein kinases and p53.The mechanisms of sensory hair cell degeneration in response to different ototoxic stimuli share a final common pathway: caspase activation. Inhibition of caspases prevents or delays hair cell death and may preserve hearing/balance function. Inhibition of mitogen-activated protein kinases protects against noise-induced and aminoglycoside-induced but not cisplatin-induced hair cell death, which suggests divergent upstream regulatory mechanisms.

  View details for PubMedID 16282762

• Auramine orange stain with fluorescence microscopy is a rapid and sensitive technique for the detection of cervical lymphadenitis due to mycobacterial infection using fine needle aspiration cytology: a case series OTOLARYNGOLOGY-HEAD AND NECK SURGERY Cheng, A. G., Chang, A., Farwell, D. G., Agoff, S. N. 2005; 133 (3): 381-385

  Abstract

  We sought to evaluate the effectiveness of the auramine orange (AO) stain in diagnosing mycobacterial cervical adenitis (MCA) from fine needle aspiration (FNA) cytology.A retrospective review of 19 patients evaluated at 2 urban hospitals from 2000 to 2003 for suspected MCA. FNA specimens were inoculated to culture media and had direct smears stained by the auramine acid fast method.Mycobacteria were identified in 16 (84.2%) of 19 AO-stained FNA specimens, with results available within 4 hours. Corresponding cultures were positive for mycobacteria in 12 specimens, 9 tuberculous and 3 nontuberculous, and grew Mycobacterium tuberculosis from the 3 AO-negative specimens. Three of the 4 patients with negative cultures had previously taken anti-mycobacterial medications.The AO stain with fluorescence microscopy is a sensitive and rapid method for detecting tuberculous and nontuberculous mycobacteria. It is a valuable tool for the otolaryngologists and pathologists in the diagnosis of MCA.

  View details for DOI 10.1016/j.otohns.2005.04.027

  View details for Web of Science ID 000231748100015

  View details for PubMedID 16143186

• Neomycin-induced hair cell death and rapid regeneration in the lateral line of zebrafish (Danio rerio) JARO-JOURNAL OF THE ASSOCIATION FOR RESEARCH IN OTOLARYNGOLOGY Harris, J. A., Cheng, A. G., Cunningham, L. L., MacDonald, G., Raible, D. W., Rubel, E. W. 2003; 4 (2): 219-234

  Abstract

  Mechanoreceptive hair cells are extremely sensitive to aminoglycoside antibiotics, including neomycin. Hair cell survival was assessed in larval wild-type zebrafish lateral line neuromasts 4 h after initial exposure to a range of neomycin concentrations for 1 h. Each of the lateral line neuromasts was scored in live fish for the presence or absence of hair cells using the fluorescent vital dye DASPEI to selectively label hair cells. All neuromasts were devoid of DASPEI-labeled hair cells 4 h after 500 microM neomycin exposure. Vital DASPEI staining was proportional to the number of hair cells per neuromast identified in fixed larvae using immunocytochemistry for acetylated tubulin and phalloidin labeling. The time course of hair cell regeneration in the lateral line neuromasts was also analyzed following neomycin-induced damage. Regenerated hair cells were first observed using live DASPEI staining 12 and 24 h following neomycin treatment. The potential role of proliferation in regenerating hair cells was analyzed. A 1 h pulse-fix protocol using bromodeoxyuridine (BrdU) incorporation was used to identify S-phase cells in neuromasts. BrdU incorporation in neomycin-damaged neuromasts did not differ from control neuromasts 4 h after drug exposure but was dramatically upregulated after 12 h. The proliferative cells identified during a 1 h period at 12 h after neomycin treatment were able to give rise to new hair cells by 24-48 h after drug treatment. The results presented here provide a standardized preparation for studying and identifying genes that influence vertebrate hair cell death, survival, and regeneration following ototoxic insults.

  View details for DOI 10.1007/s10162-002-3022-x

  View details for Web of Science ID 000184781600008

  View details for PubMedID 12943374

• Hair cell death in the avian basilar papilla: Characterization of the in vitro model and caspase activation JARO-JOURNAL OF THE ASSOCIATION FOR RESEARCH IN OTOLARYNGOLOGY Cheng, A. G., Cunningham, L. L., Rubel, E. W. 2003; 4 (1): 91-105

  Abstract

  Caspases are a family of proteases that have been implicated as key mediators of cell death. Although nonspecific inhibition of caspase activation has been reported to prevent mammalian sensory hair cell death, the exact roles of individual caspases during hair cell death are unclear. In other systems, the activation of initiator caspases, such as caspase-8 and caspase-9, can lead to the activation of the effector caspase-3. We have begun to systematically characterize hair cell death in an in vitro system by examining the activation of these specific caspases in degenerating hair cells after acutely damaging the whole avian basilar papilla with gentamicin. Basilar papillae (BP) displayed a dose-dependent hair cell loss after a 24-h treatment with gentamicin at concentrations of 0.1, 0.5, and 2.0 mM. When treated with 0.5 mM gentamicin for 6, 12, or 24 h, hair cells first began to degenerate in the basal third of the BP and damage progressed apically. Supplementation of z-VAD-fmk, a general caspase inhibitor, provided short-term protection against gentamicin-induced hair cell death. Treatment with gentamicin for 6 or 12 h promoted the expression of active caspase-3 and active caspase-9 in many hair cells along the BP as shown by immunohistochemistry. At these time-points, specific fluorescent-labeled peptide substrates detected more active caspase-3, caspase-8, and caspase-9 in gentamicin-treated hair cells relative to controls. Our data indicate that auditory hair cells degenerate as a result of gentamicin exposure in a caspase-dependent manner. Specifically, the upstream caspases, caspase-8 and caspase-9, and the downstream caspase-3 are activated in aminoglycoside-damaged hair cells.

  View details for DOI 10.1007/s10162-002-3016-8

  View details for Web of Science ID 000181329000008

  View details for PubMedID 12417974

• Caspase activation in hair cells of the mouse utricle exposed to neomycin JOURNAL OF NEUROSCIENCE Cunningham, L. L., Cheng, A. G., Rubel, E. W. 2002; 22 (19): 8532-8540

  Abstract

  Aminoglycoside exposure results in the apoptotic destruction of auditory and vestibular hair cells. This ototoxic hair cell death is prevented by broad-spectrum caspase inhibition. We have used in situ substrate detection, immunohistochemistry, and specific caspase inhibitors to determine which caspases are activated in the hair cells of the adult mouse utricle in response to neomycin exposure in vitro. In addition, we have examined the hierarchy of caspase activation. Our data indicate that both upstream caspase-8 and upstream caspase-9, as well as downstream caspase-3 are activated in hair cells exposed to neomycin. The inhibition of caspase-9-like activity provided significant protection of hair cells exposed to neomycin, whereas the inhibition of caspase-8-like activity was not effective in preventing neomycin-induced hair cell death. In addition, caspase-9 inhibition prevented the activation of downstream caspase-3, whereas the inhibition of caspase-8 did not. These data indicate that caspase-9 is the primary upstream caspase mediating neomycin-induced hair cell death in this preparation.

  View details for Web of Science ID 000178246000021

  View details for PubMedID 12351727

• Oxidative stress-induced apoptosis of cochlear sensory cells: otoprotective strategies INTERNATIONAL JOURNAL OF DEVELOPMENTAL NEUROSCIENCE Huang, T., Cheng, A. G., Stupak, H., Liu, W., Kim, A., Staecker, H., LEFEBVRE, P. P., Malgrange, B., Kopke, R., Moonen, G., Van de Water, T. R. 2000; 18 (2-3): 259-270

  Abstract

  Apoptosis is an important process, both for normal development of the inner ear and for removal of oxidative-stress damaged sensory cells from the cochlea. Oxidative-stressors of auditory sensory cells include: loss of trophic factor support, ischemia-reperfusion, and ototoxins. Loss of trophic factor support and cisplatin ototoxicity, both initiate the intracellular production of reactive oxygen species and free radicals. The interaction of reactive oxygen species and free radicals with membrane phospholipids of auditory sensory cells creates aldehydic lipid peroxidation products. One of these aldehydes, 4-hydroxynonenal, functions as a mediator of apoptosis for both auditory neurons and hair cells. We present several approaches for the prevention of auditory sensory loss from reactive oxygen species-induced apoptosis: 1) preventing the formation of reactive oxygen species; (2) neutralizing the toxic products of membrane lipid peroxidation; and 3) blocking the damaged sensory cells' apoptotic pathway.

  View details for Web of Science ID 000086197800017

  View details for PubMedID 10715580

• Calpain inhibitors protect auditory sensory cells from hypoxia and neurotrophin-withdrawal induced apoptosis BRAIN RESEARCH Cheng, A. G., Huang, T., Stracher, A., Kim, A., Liu, W., Malgrange, B., LEFEBVRE, P. P., Schulman, A., Van De Water, T. R. 1999; 850 (1-2): 234-243

  Abstract

  Inhibitors of calpain have been shown to protect nerve growth factor (NGF)-deprived ciliary ganglion neurons and hypoxic cortical neurons. Calpains have been identified in the cochlea and are active during ischemic injury. Since apoptosis can be initiated by loss of neurotrophic support, hypoxia, and ototoxins (e.g., cisplatin, CDDP), the role of calpain inhibitors under these conditions was examined in auditory hair cells and neurons. Dissociated spiral ganglion neuron (SGN) cell cultures and organ of Corti explants from P3 rats were used to test the efficacy of calpain inhibitors as otoprotective molecules. Our results indicate that calpain inhibitor I, calpain inhibitor II, and leupeptin all provided significant protection of SGNs against neurotrophin-withdrawal and hypoxia-induced apoptosis. The increase in neuronal survival ranged from 2.16 to 2.31 times greater than in untreated neurotrophin-withdrawn SGN cell cultures. BOC-Asp(Ome)-Fluoromethyl Ketone (B-D-FMK), a general caspase inhibitor, increased neuronal survival 2.16 times more. Neuronal survival rates were from 1.88 to 2.27 times greater than in untreated, hypoxic neurons and hair cell survival rates were from 1.98 to 2.03 times greater than untreated, hypoxic organ of Corti explants. However, protection of auditory hair cells and neurons from CDDP-induced damage (10 and 6 micrograms/ml, respectively) was limited with any of these calpain inhibitors. Apoptotic pathways initiated by neurotrophin-deprivation and ototoxic stress (e.g., CDDP) have been shown to be different. Our results agree with this finding, with neurotrophin-withdrawal and hypoxia, but not CDDP damage-induced apoptosis being calpain-dependent.

  View details for Web of Science ID 000084222800027

  View details for PubMedID 10629769

• LATERAL VENTRICULAR EFFACEMENT AS AN ISOLATED SONOGRAPHIC FINDING IN PREMATURE-INFANTS - PREVALENCE AND SIGNIFICANCE AMERICAN JOURNAL OF ROENTGENOLOGY Patel, M. D., Cheng, A. G., Callen, P. W. 1995; 165 (1): 155-159

  Abstract

  The sonographic finding of effaced lateral ventricles in premature infants, defined as the absence of visible CSF within the lateral ventricles on both coronal and sagittal sonograms, may be cause to suspect diffuse cerebral edema, especially as published reference standards do not address this phenomenon. This investigation was undertaken to determine the prevalence and significance of effaced lateral ventricles without associated parenchymal abnormality (isolated lateral ventricular effacement, or ILVE) in premature infants.Sonographic records of 398 consecutive newborns examined from January 1 to December 31, 1993, were reviewed retrospectively to identify those premature infants (< 36 weeks of gestational age) whose initial sonograms showed no evidence of intracranial hemorrhage, ventriculomegaly, structural abnormality, or abnormal parenchymal echogenicity. We identified 142 neonates who met these criteria. Patients were separated into two groups on the basis of whether they had at least one sonographic study in which CSF was not visible within both lateral ventricles on coronal and sagittal images. Medical records were reviewed to assess neurologic outcome.Forty patients (28%) had at least one sonogram demonstrating ILVE, with neurologic follow-up in 33 (representing group A). One hundred two patients (72%) never demonstrated ILVE, with neurologic follow-up established in 86 (representing group B). A comparison of the two groups showed no significant difference in the development of ischemic injury (one patient in each group). ILVE was first detected on the initial sonogram obtained (mean, 4 days) in 30 of the 33 neonates in group A. ILVE was demonstrated beyond the seventh day of life in 30%. Of the 89 patients whose initial sonograms showed CSF in the lateral ventricles (86 in group B and three in group A), three (3%) subsequently had sonograms that showed ILVE; all three were normal at follow-up.ILVE in premature infants is common and not associated with neurologic deficits indicative of hypoxic-ischemic encephalopathy. By itself, ILVE is not a significant finding.

  View details for Web of Science ID A1995RE24000036

  View details for PubMedID 7785575