Yi-Bo Huang

Survival and fate of transplanted embryonic neural stem cells by Atoh1 gene transfer in guinea pigs cochlea

Embryonic neural stem cells (NSCs) were isolated from the neuroepithelium of the dorsal telencephalon of embryonic rats and infected by Ad5-Atoh1-enhanced green fluorescent protein. These NSCs were then delivered into neurosphere culture medium or transplanted into the endolymphatic space of the normal guinea pig cochlea through cochleostomy. Embryonic NSC phenotype of these isolated cells was determined by immunohistochemical detection of cell-specific protein markers. Survival, location and hair cell (HC) differentiation of the implanted NSCs were determined by the expression of the report gene, enhanced green fluorescent protein, and a specific marker for HCs, Myosin VIIa. These implanted cells can survive in the endolymphatic space of the cochlea. Some of the surviving cells differentiated into HCs by Atoh1 gene transfer.

Shrinkage of ipsilateral taste buds and hyperplasia of contralateral taste buds following chorda tympani nerve transection

The morphological changes that occur in the taste buds after denervation are not well understood in rats, especially in the contralateral tongue epithelium. In this study, we investigated the time course of morphological changes in the taste buds following unilateral nerve transection. The role of the trigeminal component of the lingual nerve in maintaining the structural integrity of the taste buds was also examined. Twenty-four Sprague-Dawley rats were randomly divided into three groups: control, unilateral chorda tympani nerve transection and unilateral chorda tympani nerve transection + lingual nerve transection. Rats were allowed up to 42 days of recovery before being euthanized. The taste buds were visualized using a cytokeratin 8 antibody. Taste bud counts, volumes and taste receptor cell numbers were quantified and compared among groups. No significant difference was detected between the chorda tympani nerve transection and chorda tympani nerve transection + lingual nerve transection groups. Taste bud counts, volumes and taste receptor cell numbers on the ipsilateral side all decreased significantly compared with control. On the contralateral side, the number of taste buds remained unchanged over time, but they were larger, and taste receptor cells were more numerous postoperatively. There was no evidence for a role of the trigeminal branch of the lingual nerve in maintaining the structural integrity of the anterior taste buds.

Expression of Numb and Numb-like in the development of mammalian auditory sensory epithelium.

The Numb and Numb-like are evolutionarily conserved cell fate-determining factors in mammals. For the first time, we investigate the involvement of the Numb and Numb-like in the developing auditory sensory epithelium. We show that both of them are expressed in the rat auditory sensory epithelium, and the four isoforms of the Numb have dynamic expression patterns during cochlear development. At the early stage of the auditory epithelium development, they occur in all progenitor cells. At the late stage of cell differentiation, they are expressed mainly in the cytoplasm of apical cells and their locations are different. Furthermore, we find overexpression of the Numb or Numb-like, in cochlear whole mount cultures, can upregulate mRNA level of Rath1, which is important in the hair-cell development.

Cutaneous neuroendocrine carcinoma of the external auditory canal: a case report and review of the literature.

Cutaneous neuroendocrine carcinoma (cNEC) is rarely seen in the external ear. In this paper, we newly describe a patient with cNEC in his right external auditory canal, followed by a further discussion on the clinical features, diagnosis, and treatments of cNEC of the external ear. A review of the literature showed that cNEC of the external auditory canal generally presents as asymptomatic and that pathology yields the most confirmative diagnosis. A wide resection with adjuvant radiotherapy and chemotherapy is recommended. The overall prognosis of this condition is poor.

Changes in ADF/destrin expression in the development of hair cells following Atoh1-induced ectopic regeneration

The aim of this study was to investigate the effects of actin depolymerizing factor (ADF)/destrin and position changes of kinetosomes in the development of hair cells following Atoh1-induced ectopic regeneration in the basilar membrane of mice. We observed through immunofluorescence at various time-points the expression of ADF/destrin and the specific kinetosome marker, γ-tubulin, in hair cells following ectopic regeneration induced by adenovirus transfection, overexpression of Atoh1 and in vitro culture. Changes of ADF/destrin distribution and kinetosome position during in vitro culture of new hair cells [Myo7a(+)] following Atoh1-induced ectopic regeneration are consistent with the changes in ADF/destrin expression and the polar migration of kinetosomes in hair cells of the cochlear sensory epithelium in normal development. ADF/destrin is involved in the development of the auditory epithelium and the development and structural rearrangement of ectopically regenerated hair cells in mammals. The kinetosomes of hair cells following Atoh1-induced ectopic regeneration show positional changes in vitro at different time-points.

Three-Dimensional Reconstruction of C57BL/6 Mouse Inner Ear during Development

Purpose: To explore the three-dimensional (3-D) morphological characteristics of the complicated inner ear development of the C57BL/6 mouse. Methods: Specimens of C57BL/6 mouse embryos on days E7.5, E8.5, E9.5, E10.5, E11.5, E12.5 and E14.5 were collected and sectioned serially in this experiment. After hematoxylin and eosin staining, parts of the inner ear were pictured under the microscope with specific positional control. Using the protocol of 3D-DOCTOR software, we outlined the inner ear margin including the inner and extra face in different colors and put them into the 3-D program to reconstruct the 3-D model. Results: 3-D models of the E9.5, E10.5, E11.5, E12.5 and E14.5 inner ear were obtained and proved to be fine. Different parts of the inner ear were shown clearly in different colors in the 3-D model and significant morphological changes of the inner ear were shown during development between E9.5 and E14.5. Conclusion: The new technology of 3-D reconstruction is a useful and important tool to directly observe the complex development of the inner ear, and the development between E9.5 and E14.5 has been proved by the 3-D model to be the most complex and important period of the development of the C57BL/6 mouse inner ear.

Cell proliferation during hair cell regeneration induced by Math1 in vestibular epithelia in vitro

Hair cell regeneration is the fundamental method of correcting hearing loss and balance disorders caused by hair cell damage or loss. How to promote hair cell regeneration is a hot focus in current research. In mammals, cochlear hair cells cannot be regenerated and few vestibular hair cells can be renewed through spontaneous regeneration. However, Math1 gene transfer allows a few inner ear cells to be transformed into hair cells in vitro or in vivo. Hair cells can be renewed through two possible means in birds: supporting cell differentiation and transdifferentiation with or without cell division. Hair cell regeneration is strongly associated with cell proliferation. Therefore, this study explored the relationship between Math1-induced vestibular hair cell regeneration and cell division in mammals. The mouse vestibule was isolated to harvest vestibular epithelial cells. Ad-Math1-enhanced green fluorescent protein (EGFP) was used to track cell division during hair cell transformation. 5-Bromo-2′-deoxyuridine (BrdU) was added to track cell proliferation at various time points. Immunocytochemistry was utilized to determine cell differentiation and proliferation. Results demonstrated that when epithelial cells were in a higher proliferative stage, more of these cells differentiated into hair cells by Math1 gene transfer. However, in the low proliferation stage, no BrdU-positive cells were seen after Math1 gene transfer. Cell division always occurred before Math1 transfection but not during or after Math1 transfection, when cells were labeled with BrdU before and after Ad-Math1-EGFP transfection. These results confirm that vestibular epithelial cells with high proliferative potential can differentiate into new hair cells by Math1 gene transfer, but this process is independent of cell proliferation.

Mechanisms of Hearing Loss in a Guinea Pig Model of Superior Semicircular Canal Dehiscence

Defective acoustic transmission in the cochlea is closely related with various auditory and vestibular symptoms. Among them, semicircular canal dehiscence (SCD) with a defective semicircular bone is typical. Currently, the pathogenesis of SCD is usually explained by the third window hypothesis; however, this hypothesis fails to explain the variability in the symptoms and signs experienced by superior SCD (SSCD) patients. We evaluated the mechanism of hearing loss in a guinea pig model of bony dehiscence with various sizes and locations along the superior semicircular canal. Auditory brainstem responses (ABRs) and laser Doppler velocimetry were used to measure hearing loss and vibration changes before and after fenestration, as well as after restorative patching. ABR thresholds at low frequencies (e.g., 1000 Hz) increased after fenestration and decreased back to the normal range after we repaired the defect. Energy leakage from the surgically introduced third window was detected in the range of 300–1500 Hz, accompanied by increased vibration at the umbo, stapes head, and the dehiscence site, while decreased vibration was observed at the round window membrane in the same frequency range. After the patching procedure, the deviant vibrations were recovered. The degree of postfenestration energy leakage was proportional to the size of fenestration and the proximity of the fenestration site to the oval window. These results suggest that the bony fenestration of the superior semicircular canal mimics the hearing loss pattern of patients with SSCD. The decrease in perilymph wave impedance likely accounts for the auditory changes.

The Role of the Notch Signal Pathway in Mucosal Cell Metaplasia in Mouse Acute Otitis Media

Otitis media (OM) is a major cause of morbidity in pediatric and adult patients. This inflammatory condition is characterized by mucous cell hyperplasia that is thought to produce mucins from the middle ear mucosa. We are interested in the role of Notch signalling pathway in this inflammatory process. Using an acute otitis media (AOM) mouse model through injection of Streptococcus Pneumoniae into the middle ear, histopathologic examination and quantitative RT-PCR, acute inflammation with the thickness of mucosa, Goblet cell hyperplasia, and cilia loss were determined and gene expression related to the Notch signaling pathway were evaluated. Upregulation of the mucous cell markers, Argr2 and Muc5AC, and downregulation of the cilia cell marker, Foxj1 and Dnai2, were observed in AOM. In addition, genes encoding Notch receptors and ligands (Notch1, Notch2, Notch3, Notch4 and Dll1) and the Notch target genes (Hes1, Hes5, Hey1, NRARP) in AOM decreased significantly. The expression of the Notch1 and Jagged1 also showed down-regulation throughout the mouse middle ear epithelium. Taken together, this study suggests that downregulation of the Notch signaling pathway is involved in the mucosa hyperplasia during AOM.

Contents Vol. 71, 2009

R.L. Alford, Houston, Tex. M. Anniko, Uppsala D.D. Backous, Seattle, Wash. Y.A. Bayazit, Ankara H.H. Birdsall, Houston, Tex. P.J. Bradley, Nottingham J. Califano, Baltimore, Md. P.F. Castellanos, Bimingham, Ala. C. Cernea, São Paulo F.-L. Chi, Shanghai A. Chiu, Philadelphia, Pa. N. Cohen, Philadelphia, Pa. M.D. Eisen, Hartford, Conn. E. Ferekidis, Athens A. Ferlito, Udine R.L. Ferris, Pittsburgh, Pa. L.L. Gleich, Cincinnati, Ohio D.-M. Han, Beijing J.P. Harris, San Diego, Calif. R. Häusler, Bern I. Hochmair, Innsbruck K. Hörmann, Mannheim W. Hosemann, Greifswald K.-B. Hüttenbrink, Köln S. Iurato, Bari A. Kakigi, Tokyo B.N. Landis, Geneva T. Linder, Luzern W.J. Mann, Mainz J.J. Manni, Maastricht J.B. Nadol, Jr., Boston, Mass. J.N. Palmer, Philadelphia, Pa. G.J. Petruzzelli, Chicago, Ill. R. Probst, Zürich A. Rinaldo, Udine R.J. Ruben, Bronx, N.Y. I. Salahuddin, Karachi A. Schrott-Fischer, Innsbruck A. Shiotani, Saitama G.A. Tavartkiladze, Moscow T.N. Teknos, Columbus, Ohio K. Tomoda, Osaka R.P. Tufano, Baltimore, Md. R.T. Younis, Miami, Fla. P. Zbären, Bern Journal for Oto-Rhino-Laryngology, Head and Neck Sugery