Isolation and Characterization of Mammalian Otic Progenitor Cells that Can Differentiate into Both Sensory Epithelial and Neuronal Cell Lineages.

The mammalian inner ear mediates hearing and balance and during development generates both cochleo-vestibular ganglion neurons and sensory epithelial receptor cells, that is, hair cells and support cells. Cell marking experiments have shown that both hair cells and support cells can originate from a common progenitor. Here, we demonstrate the lineage potential of individual otic epithelial cell clones using three cell lines established by a combination of limiting dilution and gene-marking techniques from an embryonic day 12 (E12) rat otocyst. Cell-type specific marker analyses of these clonal lines under proliferation and differentiation culture conditions demonstrate that during differentiation immature cell markers (Nanog and Nestin) were downregulated and hair cell (Myosin VIIa and Math1), support cell (p27Kip1 and cytokeratin) and neuronal cell (NF-H and NeuroD) markers were upregulated. Our results suggest that the otic epithelium of the E12 mammalian inner ear possess multipotent progenitor cells able to generate cell types of both sensory epithelial and neural cell lineages when cultured under a differentiation culture condition. Understanding the molecular mechanisms of proliferation and differentiation of multipotent otic progenitor cells may provide insights that could contribute to the development of a novel cell therapy with a potential to initiate or stimulate the sensorineural repair of damaged inner ear sensory receptors. Anat Rec, 303:451-460, 2020. © 2019 American Association for Anatomy.

Multifocal hyperfunctioning thyroid carcinoma without metastases.

Hyperthyroidism due to thyroid carcinoma is rare, and most cases are caused by hyperfunctioning metastatic thyroid carcinoma rather than primary carcinoma. Among primary hyperfunctioning thyroid carcinoma, multifocal thyroid carcinoma is exceedingly rare, with the only one case being reported in the literature. Here, we describe the case of a 62-year-old woman with multifocal functioning thyroid carcinoma. Technetium-99m (99m Tc) scintigraphic imaging showed four hot areas in the thyroid gland. Histopathological examination of all four nodules revealed papillary carcinoma, corresponding to hot areas in the 99m Tc scintigram. DNA sequencing of the thyrotropin receptor (TSH-R) gene from all nodules revealed no mutation, indicating that activation of TSH-R was unlikely in the pathophysiogenesis of hyperfunctioning thyroid carcinoma in the present case.

Therapeutic outcomes of oral cancers at Kyoto University Hospital.

CONCLUSION: The results suggest that early diagnosis and treatment are the most important factors to improve the prognosis in oral cancer patients. OBJECTIVE: In this retrospective study we analyzed the therapeutic outcome of oral cancers at out institute. PATIENTS AND METHODS: Thirty-one patients with oral cancers were treated between January 2000 and December 2004 at the Department of Otolaryngology-Head and Neck Surgery, Kyoto University Hospital. Transoral resection of tumor with or without neck dissection was performed for early oral cancers (stage I and II), while more extensive resection and radical neck dissection followed by postoperative radiotherapy was performed for advanced cases (stage IIII and IV). In the treatment of early tongue cancer, either partial glossectomy or brachytherapy was selected. The 3-year disease-specific survival rates of all patients, early-staged, and advanced-staged patients were 82.2%, 92.9%, and 63.5%, respectively. The prognosis was significantly related to the clinical stage of the tumor.

OC29 is preferentially expressed in the presumptive sensory organ region of the otocyst.

The mammalian inner ear derives from the otocyst. Molecular mechanisms underlying inner ear development are largely unknown. We have isolated a secreted molecule, OC29, from a rat otocyst cDNA library by the signal sequence trap method. OC29 was revealed to be a rat homologue of human WFIKKN. OC29 is preferentially expressed in the developing inner ear and the dorsal neural tube. In the inner ear, the expression of OC29 is first detectable at embryonic day 11.5 (E11.5), broadly in the dorsolateral region of the otocyst, which gives rise to the vestibular organ. At E12.5, the expression of OC29 becomes restricted to the presumptive sensory region, mainly to the BMP4-positive presumptive cristae, and expression becomes reduced at later stages. These results suggest that OC29 may have a role in the early development of the inner ear sensory organ, particularly in the formation of the cristae of the semicircular canals.

Generation of inner ear hair cell immunophenotypes from neurospheres obtained from fetal rat central nervous system in vitro.

Neural stem cells are suggested to possess a highly plastic ability to differentiate into several specific cell types, not only neuronal lineages but also other germ layer tissue-specific cell lineages. To examine whether hair cell immunophenotypes could be derived from the central nervous system (CNS), we established cell cultures from embryonic day 16.5 fetal rat brain tissues, and analyzed changes in immunohistochemical features of the CNS cell cultures by induction of differentiation. The results of this study showed that neural progenitors obtained from fetal rat CNS generated hair cell immunophenotypes with expression of both epitopes of hair cell marker proteins Brn-3c and myosin VIIa in vitro. These findings indicate that immature neural progenitors possess the potential to differentiate into hair cell phenotypes. Immature neural progenitors may be useful as materials for cell transplantation therapy for replacement of damaged inner ear hair cells.

Transplantation of neural stem cells into explants of rat inner ear.

Damage and loss of hair cells in the inner ear is the most frequent cause of hearing loss and balance disorders. Mammalian hair cells do not regenerate in the conventional ways. To regenerate the hair cell in the mammalian inner ear we transplanted neural stem cells into explants of rat inner ear. The stem cells integrated successfully into the sensory epithelium of the vestibular organs, but not into the organ of Corti. This method is useful to investigate efficient ways to transplant stem cells into the inner ear.

Expression of calretinin by fetal otocyst cells after transplantation into damaged rat utricle explants.

Severe damage by acoustic overstimulation or ototoxins induces inner ear hair cell loss, resulting in permanent hearing loss and balance disorders because hair cell regeneration scarcely occurs in the inner ear sensory organs of mammals. In this study, to evaluate the possibilities of cell transplantation therapy for damaged inner ear sensory organs, dissociated cell cultures of fetal otocyst cells (FOCs) were established from embryonic day 12.5 (E12.5) rat inner ears, and transplanted into gentamicin-treated explants of vestibular sensory epithelia. Two weeks after transplantation, immunohistochemical analysis demonstrated that some of the grafted FOCs survived within the vestibular sensory epithelia and expressed epitopes of calretinin. one of the hair cell marker proteins. These findings indicate that FOCs have the potential to migrate into damaged vestibular epithelia and differentiate into hair cell immunophenotypes. Cell transplantation therapy may be available for functional regeneration in inner ear diseases.