Ichiro Tateya

Immediate Inflammatory Response and Scar Formation in Wounded Vocal Folds

Objectives: Vocal fold scarring is the major cause of voice disorders after voice surgery or laryngeal trauma. The role of inflammatory factors in vocal fold wound healing and fibrosis has not been adequately investigated. Scarless wound healing has been associated with decreased inflammatory responses. To understand scar formation and develop reliable treatments, it is necessary to control extracellular matrix production and inflammation. Thus, we examined the inflammation profile and extracellular matrix production in wounded vocal folds in the acute phase of wound healing. Methods: Vocal fold stripping was performed on 30 Sprague-Dawley rats. Vocal fold tissue was collected at 5 time points (4, 8, 16, 24, and 72 hours). We examined the in vivo messenger RNA expression profile of inflammatory factors interleukin 1β, interferon γ, tumor necrosis factor a, nuclear factor Kβ, transforming growth factor β, and cyclooxygenase 2, as well as hyaluronic acid synthases 1 and 2, procollagen subtypes I and III, and elastin synthase in scarred vocal folds after injury, compared to normal vocal folds, using real-time reverse transcription-polymerase chain reaction. Results: The inflammatory factors showed a time-dependent sequence of expression peaks, starting with interleukin 1β, nuclear factor Kβ, tumor necrosis factor a (4 and 8 hours), and transforming growth factor β (72 hours). Interferon y decreased at 24 hours. Correspondingly, hyaluronic acid synthase 1 expression peaked first (4 and 8 hours), whereas hyaluronic acid synthase 2 expression peaked at 16 hours and again at 72 hours. Procollagen I expression peaked at 72 hours, whereas procollagen III decreased from 8 to 16 hours but peaked at 72 hours. Cyclooxygenase 2 expression was elevated, whereas elastin expression remained constant. Conclusions: The results show a clear profile of vocal fold inflammation with corresponding changes in extracellular matrix production.

Cooperative functions of Hes/Hey genes in auditory hair cell and supporting cell development.

Notch-mediated lateral inhibition has been reported to regulate auditory hair cell and supporting cell development from common precursors. While the Notch effector genes Hes1, Hes5 and Hey1 are expressed in the developing cochlea, inactivation of either of them causes only mild abnormality, suggesting their functional redundancy. To explore the roles of Hes/Hey genes in cochlear development, we examined compound heterozygous or homozygous mutant mice that lacked Hes1, Hes5 and Hey1 alleles. We found that a reduction in Hes/Hey gene dosage led to graded increase of hair cell formation. However, if at least one allele of Hes1, Hes5 or Hey1 was intact, excessive hair cells were accompanied by overproduction of supporting cells, suggesting that the hair cell increase does not occur at the expense of supporting cells, and that each Hes/Hey gene functions to induce supporting cells. By contrast, when all alleles of Hes1, Hes5 and Hey1 were inactivated, the number of hair cells increased more drastically, whereas that of supporting cells was unchanged compared with control, suggesting that supporting cell formation was balanced by their overproduction and fate conversion into hair cells. The increase of the cell numbers seemed to occur after the prosensory domain formation in the mutants because the proliferation state and the size of the prosensory domain were not affected. Thus, Hes1, Hes5 and Hey1 cooperatively inhibit hair cell formation, and one allele of Hes1, Hes5 or Hey1 is sufficient for supporting cell production probably by lateral inhibition in the sensory epithelium. Strikingly, Hes/Hey mutations lead to disorganized cell alignment and polarity and to hearing loss despite hair cell overproduction. These results suggest that Hes/Hey gene dosage is essential not only for generation of appropriate numbers of hair cells and supporting cells by controlling cell proliferation and lateral inhibition but also for the hearing ability by regulating the cell alignment and polarity.

Chronic vocal fold scar restoration with hepatocyte growth factor hydrogel

Therapeutic challenges exist in the management of vocal fold scarring. We have previously demonstrated the therapeutic potential of hepatocyte growth factor (HGF) in the management of acute phase vocal fold scarring using a novel hydrogel‐based HGF drug delivery system (DDS). However, the effect of HGF on matured vocal fold scarring remains unclear. The current study aims to investigate the effect of HGF‐DDS on chronic vocal fold scarring using a canine model.

Histological Study of Acute Vocal Fold Injury in a Rat Model

Objectives: We used an acute vocal fold injury in a rat model to characterize vocal fold wound healing by studying the expression pattern of the extracellular matrix components in the vocal fold lamina propria. Methods: Vocal fold stripping was performed unilaterally in 27 Sprague-Dawley rats. The vocal folds were harvested at 5 time points (1, 3, 5, 7, and 14 days) and histologically analyzed by Alcian blue stain, trichrome stain, and immunofluorescence with antibodies to collagen type I, collagen type III, and fibronectin. Results: Re-epithelialization occurred by day 3 and was complete by day 14. Granulation tissue was formed by day 3. Hyaluronic acid and collagen type I appeared in injured vocal folds by day 3, peaked at day 5, and thereafter decreased. Collagen type III and fibronectin appeared by day 1 and continued to be intense at all time points after day 3. Conclusions: These results suggest that the expression of these extracellular matrix components peaks in the period around days 3 to 5, and that the characteristics of wound healing in the vocal fold are similar to those in the skin in the early phases, but differ during the subsequent remodeling phase.

Increased cortical activation during hearing of speech in cochlear implant users

To investigate the cortical activities while listening to noise and speech in cochlear implant (CI) users, we compared cerebral blood flow in postlingually deafened CI users with that in normal hearing subjects using positron emission tomography. While noise activation in CI users did not significantly differ from that in normal subjects, hearing speech activated more cortical areas in CI users than in normal subjects. A comparison of speech activation in these two groups revealed higher activation in CI users not only in the temporal cortices but also in Brocas area and its right hemisphere homologue, the supplementary motor area and the anterior cingulate gyrus. In postlingually deafened subjects, the hearing of speech coded by CI may be accompanied by increased activation of both the temporal and frontal cortices.

Transplantation of neural stem cells into the modiolus of mouse cochleae injured by cisplatin.

This study aimed to examine the possibility of restoration of spiral ganglion neurons, which transmit sound stimulation to the brain, by transplantation of fetal neural stem cells (NSCs) into the modiolus of cochleae. Fetal mouse NSCs expressing green fluorescence were injected into the modiolus of cisplatin-treated cochleae of mice. The temporal bones were collected 14 days after transplantation, and provided histological examination. The cell fate of transplants was determined by immunohistochemistry for a neural or glial cell-marker. Histological analysis 2 weeks after transplantation revealed robust survival of transplant-derived cells in the modiolus of the cochlea. NSCs injected in the basal portion of cochleae migrated as far as the apical end of the modiolus Grafted NSCs expressing a neural cell marker were identified, but the majority of grafted NSCs differentiated into glial cells. These findings suggest the possible use of NSCs in cell therapy for restoration of spiral ganglion neurons. However, further treatments are required to increase the number of NSC-derived neurons in the modiolus to realize functional recovery.

Regeneration of Radiation Damaged Salivary Glands with Adipose-Derived Stromal Cells

Radiotherapy is one of the most effective treatments for head and neck cancer. However, the development of dry mouth syndrome is an unavoidable side effect because, in addition to the tumor, the normal salivary glands are included in the irradiation field. Previously, we investigated the protective efficacy of basic fibroblast growth factor (bFGF) in radiation‐damaged salivary glands. In this study, we investigated the efficacy of adipose‐derived stromal cell (ADSC) transplantation for the regeneration of radiation damaged salivary glands.

Increased Expression of Phosphatidylcholine (16:0/18:1) and (16:0/18:2) in Thyroid Papillary Cancer

A good prognosis can be expected for most, but not all, cases of thyroid papillary cancer. Numerous molecular studies have demonstrated beneficial treatment and prognostic factors in various molecular markers. Whereas most previous reports have focused on genomics and proteomics, few have focused on lipidomics. With the advent of mass spectrometry (MS), it has become possible to identify many types of molecules, and this analytical tool has become critical in the field of omics. Recently, imaging mass spectrometry (IMS) was developed. After a simple pretreatment process, IMS can be used to examine tissue sections on glass slides with location information. Here, we conducted an IMS analysis of seven cases of thyroid papillary cancer by comparison of cancerous with normal tissues, focusing on the distribution of phospholipids. We identified that phosphatidylcholine (16:0/18:1) and (16:0/18:2) and sphingomyelin (d18:0/16:1) are significantly higher in thyroid papillary cancer than in normal thyroid tissue as determined by tandem mass (MS/MS) analysis. These distributional differences may be associated with the biological behavior of thyroid papillary cancer.

Long-term outcome of transoral organ-preserving pharyngeal endoscopic resection for superficial pharyngeal cancer.

BACKGROUND Early detection of pharyngeal cancer has been difficult. We reported that narrow-band imaging (NBI) endoscopy can detect superficial pharyngeal cancer, and these lesions can be treated endoscopically. OBJECTIVE To assess the safety and long-term efficacy of transoral organ-preserving pharyngeal endoscopic resection (TOPER) for superficial pharyngeal cancer. DESIGN AND SETTING Retrospective 2-center cohort study. PATIENTS The study included 104 consecutive patients with superficial pharyngeal cancer. INTERVENTION TOPER with the patients under general anesthesia. MAIN OUTCOME MEASUREMENTS Safety of the procedure, long-term survival, clinical outcome. RESULTS A total of 148 consecutive lesions were resected in 104 patients. There was no severe adverse event. Temporary tracheostomy was required in 17 patients (16%) to prevent airway obstruction. The median fasting period and hospital stay after TOPER were 2 days (range 1-20 days) and 8 days (range 3-58 days), respectively. Ninety-six patients (92%) had no local recurrence or distant metastases. Local recurrence at the primary site developed in 6 patients, but all were resolved by repeat TOPER. With a median follow-up period of 43 months (range 3-96 months), the overall survival rate at 5 years was 71% (95% CI, 59-82). Cause-specific survival rate at 5 years was 97% (95% CI, 93-100). The cumulative development rate of multiple cancers in pharyngeal mucosal sites at 5 years was 22% (95% CI, 12-33). The pharynx was preserved in all patients, and they experienced no loss of function. LIMITATION Retrospective design. CONCLUSIONS Peroral endoscopic resection of superficial pharyngeal cancer is a feasible and effective treatment with curative intent.

Inflammatory factor profiles one hour following vocal fold injury.

Objectives Inflammatory factors are key mediators of wound healing processes following injury, and their modulation may improve healing outcomes. The objective of this study was to characterize in vivo inflammatory factor and extracellular matrix (ECM) messenger RNA (mRNA) expression levels 1 hour after vocal fold injury. Methods Five Sprague-Dawley rats were subjected to bilateral vocal fold injury, 5 rats were reserved as uninjured controls, and 1 rat was subjected to unilateral vocal fold injury and reserved for histology. Tissue was harvested 1 hour after injury. Real-time reverse transcription–polymerase chain reaction was performed to examine the mRNA expression profiles of inflammatory factors nuclear factor kappa beta (NF-κ β), interferon gamma (IFN-γ), cyclooxygenase 2 (COX-2), transforming growth factor beta isoform 1 (TGF-β1), tumor necrosis factor alpha (TNF-α), and interleukin 1 beta (IL-1β), as well as ECM genes hyaluronic acid synthase (HAS) 1, HAS-2, procollagen 1, procollagen 3, and elastin, in the injured samples compared with the uninjured controls. Results Injury resulted in subepithelial bleeding throughout the vocal fold. The COX-2, TNF-α, IL-1β, and HAS-1 mRNA expression levels were significantly up-regulated 1 hour after injury compared with the uninjured controls. Conclusions Inflammatory factor and ECM gene expression changes occur in vocal fold wound sites as early as 1 hour after injury. These results should inform future efforts to attenuate vocal fold scarring via the modulation of inflammatory factors.