Kaori Kanaya

Age-related changes in cell dynamics of the postnatal mouse olfactory neuroepithelium: Cell proliferation, neuronal differentiation, and cell death

Age‐related changes in cell proliferation, neuronal differentiation, and cell death in mouse olfactory neuroepithelium were investigated. Mice at the age of 10 days through 16 months were given a single injection of bromodeoxyuridine (BrdU). The olfactory mucosae were fixed at 9 timepoints ranging from 2 hours to 3 months after the injection and examined using double immunostaining for BrdU and olfactory marker protein (OMP), and double staining with terminal deoxynucleotidyl transferase‐mediated biotinylated dUTP nick end labeling (TUNEL) and immunostaining for OMP. The number of BrdU‐labeled cells/mm epithelial length initially increased, peaked at 2–3 days after the BrdU injection, then declined at each age. The number of BrdU‐ and TUNEL‐labeled neuronal cells both decreased with increasing age, suggesting that the rates of both cell proliferation and cell death in the olfactory neuroepithelium decrease with increasing age. Double‐labeled cells for BrdU and OMP appeared at 7 days after injection in all age groups, suggesting that the time required for neuronal differentiation is broadly similar irrespective of age. In older age groups, smaller amounts of the newly produced cohort are integrated into the OMP‐positive ORN population, and even once it is integrated it is eliminated from the population more rapidly compared to the younger age groups. Furthermore, TUNEL assay showed that the fraction of apoptotic cells distributed in the OMP‐positive layer/total apoptotic cells decreased with age. This observation suggests that the turnover of mature ORNs is slower in the older neuroepithelium compared to the younger neuroepithelium. J. Comp. Neurol. 518:1962–1975, 2010.

Expression of IL‐33 and its receptor ST2 in chronic rhinosinusitis with nasal polyps

Interleukin (IL)−33 is a novel member of the IL‐1 cytokine family and a ligand for the orphan IL‐1 family receptor ST2. IL‐33 induces T helper 2‐type inflammatory responses and is considered to play a crucial role in allergic inflammatory reactions such as asthma and atopic dermatitis. However, the role of IL‐33 and its receptor ST2 in chronic rhinosinusitis remains unclear.

Age‐related changes of the regeneration mode in the mouse peripheral olfactory system following olfactotoxic drug methimazole‐induced damage

We investigated age‐related changes in the mode of regeneration in the mouse peripheral olfactory system after olfactotoxic drug‐induced damage. Mice at postnatal ages of 10 days, 3 months, and 16 months were given an intraperitoneal injection of methimazole to produce damage in the olfactory neuroepithelium. The olfactory neuroepithelia were harvested and analyzed immunohistochemically at various postlesion timepoints, from 1 day through to 94 days, to investigate neuroepithelial cell proliferation, the time course of neuronal differentiation, the reconstitution of neuroepithelium, and the innervation of the olfactory bulb. Functional recovery was assessed using the vanillin avoidance behavioral test. The chronological pattern in the expression of Ki67, beta III tubulin, and olfactory marker protein, molecular markers for neuronal cell proliferation and differentiation, changed similarly among the different age groups. In contrast, the extent of neuroepithelial cell proliferation after injury decreased with age, and the final histological recovery of the olfactory neuroepithelium and the innervation of the olfactory bulb were significantly smaller in the 16‐month‐old group compared to the younger age groups. These results suggest that the age‐related decline in the capacity of olfactory neuroepithelium to reconstitute neuroepithelium is associated with its age‐related decrease in proliferative activity after the neuroepithelial injury rather than changes in the process of neuronal differentiation. In spite of these incomplete anatomical recoveries, 16‐month‐old mice regained the ability to avoid vanillin solution by 1 month postlesion, suggesting that the extent of anatomical epithelial damage is not necessarily proportional to the threshold of olfactory perception. J. Comp. Neurol. 519:2154–2174, 2011.

Recovery of facial movement and facial synkinesis in Bell's palsy patients.

Objective: We examined the relationship between the time course of development of facial synkinesis in patients with Bells palsy and the severity of facial nerve damage. Study Design: Retrospective study. Setting: Tertiary referral center. Patients: Thirty-nine consecutive patients with Bells palsy who developed synkinesis. Intervention: Diagnostic. Main Outcome Measures: Subjects were divided into groups A (electroneurographic [ENoG] value, <10%; n = 31) and B (ENoG value, ≥10%; n = 8). Development of facial synkinesis was assessed based on the appearance of synkinetic potentials from the orbicularis oris muscle on the blink reflex test. Times to appearance of facial synkinesis in groups A and B were compared. The proportion of patients who developed facial synkinesis after complete recovery of facial movement was also assessed in 14 patients whose facial movement recovered completely. Results: The mean time to maximal recovery of facial movement was significantly longer in group A than in group B (p < 0.001), whereas the duration between the appearance of facial synkinesis and the onset of facial paralysis did not differ significantly between the 2 groups (p = 0.72). The proportion of patients who developed facial synkinesis after complete recovery of facial movement was significantly greater in group B than in group A (p = 0.015). Conclusion: During the course of recovery from Bells palsy, the patients with an ENoG value of 10% or greater have a higher risk of developing facial synkinesis after complete recovery of facial movement.

Local increase in IgE and class switch recombination to IgE in nasal polyps in chronic rhinosinusitis

Chronic rhinosinusitis with nasal polyps is generally characterized by local Th2 inflammation and is categorized into two subtypes in Japan: eosinophilic chronic rhinosinusitis (similar to chronic rhinosinusitis with nasal polyps in western countries) and non‐eosinophilic chronic rhinosinusitis (characterized by Th1‐dominant inflammation).

Transcription Factor Early Growth Response 3 Is Associated with the TGF-β1 Expression and the Regulatory Activity of CD4-Positive T Cells In Vivo

TGF-β1 is an important anti-inflammatory cytokine, and several regulatory T cell (Treg) subsets including CD4+CD25+Foxp3+ Tregs and Th3 cells have been reported to exert regulatory activity via the production of TGF-β1. However, it has not yet been elucidated which transcription factor is involved in TGF-β1 transcription. Early growth response 3 (Egr-3) is a zinc-finger transcription factor that creates and maintains T cell anergy. In this study, we found that Egr-3 induces the expression of TGF-β1 in both murine and human CD4+ T cells. Egr-3 overexpression in murine CD4+ T cells induced the production of TGF-β1 and enhanced the phosphorylation of STAT3, which is associated with TGF-β1 transcription. Moreover, Egr-3 conferred Ag-specific regulatory activity on murine CD4+ T cells. In collagen-induced arthritis and delayed-type hypersensitivity model mice, Egr-3–transduced CD4+ T cells exhibited significant regulatory activity in vivo. In particular, the suppression of delayed-type hypersensitivity depended on TGF-β1. In human tonsils, we found that CD4+CD25−CD45RO−lymphocyte activation gene 3 (LAG3)− T cells express membrane-bound TGF-β1 in an EGR3-dependent manner. Gene-expression analysis revealed that CD4+CD25−CD45RO−LAG3− T cells are quite different from conventional CD4+CD25+Foxp3+ Tregs. Intriguingly, the CD4+CD25−CD45RO−LAG3− T cells suppressed graft-versus-host disease in immunodeficient mice transplanted with human PBMCs. Our results suggest that Egr-3 is a transcription factor associated with TGF-β1 expression and in vivo regulatory activity in both mice and humans.

Sensory Deprivation Disrupts Homeostatic Regeneration of Newly Generated Olfactory Sensory Neurons after Injury in Adult Mice

Although it is well known that injury induces the generation of a substantial number of new olfactory sensory neurons (OSNs) in the adult olfactory epithelium (OE), it is not well understood whether olfactory sensory input influences the survival and maturation of these injury-induced OSNs in adults. Here, we investigated whether olfactory sensory deprivation affected the dynamic incorporation of newly generated OSNs 3, 7, 14, and 28 d after injury in adult mice. Mice were unilaterally deprived of olfactory sensory input by inserting a silicone tube into their nostrils. Methimazole, an olfactotoxic drug, was also injected intraperitoneally to bilaterally ablate OSNs. The OE was restored to its preinjury condition with new OSNs by day 28. No significant differences in the numbers of olfactory marker protein-positive mature OSNs or apoptotic OSNs were observed between the deprived and nondeprived sides 0–7 d after injury. However, between days 7 and 28, the sensory-deprived side showed markedly fewer OSNs and mature OSNs, but more apoptotic OSNs, than the nondeprived side. Intrinsic functional imaging of the dorsal surface of the olfactory bulb at day 28 revealed that responses to odor stimulation were weaker in the deprived side compared with those in the nondeprived side. Furthermore, prevention of cell death in new neurons 7–14 d after injury promoted the recovery of the OE. These results indicate that, in the adult OE, sensory deprivation disrupts compensatory OSN regeneration after injury and that newly generated OSNs have a critical time window for sensory-input-dependent survival 7–14 d after injury.

Cigarette Smoke Delays Regeneration of the Olfactory Epithelium in Mice

The olfactory system is a unique part of the mammalian nervous system due to its capacity for neurogenesis and the replacement of degenerating receptor neurons. Cigarette smoking is a major cause of olfactory dysfunction. However, the mechanisms by which cigarette smoke impairs the regenerative olfactory receptor neurons (ORNs) remain unclear. Here, we investigated the influence of cigarette smoke on ORN regeneration following methimazole-induced ORN injury. Administration of methimazole caused detachment of the olfactory epithelium from the basement membrane and induced olfactory dysfunction, thus enabling us to analyze the process of ORN regeneration. We found that intranasal administration of cigarette smoke solution (CSS) suppressed the recovery of ORNs and olfaction following ORN injury. Defective ORN recovery in CSS-treated mice was not associated with any change in the number of SOX2+ ORN progenitor cells in the basal layer of the OE, but was associated with impaired recovery of GAP43+ immature ORNs. In the nasal mucosa, mRNA expression levels of neurotrophic factors such as brain-derived neurotrophic factor, neurotrophin-3, neurotrophin-5, glial cell-derived neurotrophic factor, and insulin-like growth factor-1 (IGF-1) were increased following OE injury, whereas CSS administration decreased the ORN injury-induced IGF-1 expression. Administration of recombinant human IGF-1 prevented the CSS-induced suppression of ORN recovery following injury. These results suggest that CSS impairs regeneration of ORNs by suppressing the development of immature ORNs from ORN progenitors, at least partly by reducing IGF-1 in the nasal mucosa.

Bell's palsy in children: relationship between electroneurography findings and prognosis in comparison with adults.

Objectives To investigate the correlation between electroneurography (ENoG) findings and the prognosis of Bell’s palsy in children compared with adults. Methods Twenty-two children and 92 adults with Bell’s palsy who underwent ENoG between 8 days and 4 weeks from the onset of symptoms were retrospectively enrolled. The time to maximal recovery and rate of favorable recovery (House-Brackmann grade I or II) was assessed. Children (C) and adults (A) were further subdivided into low (<10%) or high (≧10%) subgroups according to their ENoG values (affected versus unaffected side) at initial evaluation. The numbers in each subgroup were as follows: C-low (n = 8), A-low (n = 21), C-high (n = 14), and A-high (n = 71). Results Of the 22 children assessed, 2 of the 4 patients who showed a total loss of evoked potentials on the affected side (0% ENoG value) exhibited an unfavorable recovery. The remaining 20 patients achieved a favorable recovery eventually. Patients in group C-low reached a maximal recovery of facial movement significantly later than those in group C-high (p < 0.001). Time to maximal recovery of facial movement in group A-low was later than that in group C-low, although the difference was not statistically significant (p = 0.15). The patients in group A-high reached a maximal recovery significantly later than those in group C-high (p < 0.05). Conclusion Bell’s palsy seems to recover earlier in children than adults when matched for severity. The presence of an identifiable response in ENoG, irrespective of its amplitude, may indicate a favorable recovery of facial movement in children.

Evaluation of the Carhart Effect in Congenital Middle Ear Malformation with Both an Intact External Ear Canal and a Mobile Stapes Footplate

The medical charts of 41 ears with congenital middle ear malformation with both an intact external ear canal and a mobile stapes footplate were reviewed retrospectively to study the Carhart effect. The operations were categorized as successful or unsuccessful according to the extent of decrease in the average air-bone gap. Statistically significant differences were observed between the 2 groups with respect to the changes in pure-tone average and the changes in the bone conduction (BC) threshold at 1 and 2 kHz. Linear regression analysis revealed weak correlations between the change in the BC threshold and the postoperative BC threshold at an overall level and at the 4 frequencies tested. Stapes ankylosis is a main cause of the Carhart effect. The present study showed that in congenital middle ear malformation, the Carhart effect was caused not only by stapes ankylosis but also by other types of disruption in the ossicular chain.