Kenji Kondo

Novel scoring system and algorithm for classifying chronic rhinosinusitis: the JESREC Study.

Chronic rhinosinusitis (CRS) can be classified into CRS with nasal polyps (CRSwNP) and CRS without nasal polyps (CRSsNP). CRSwNP displays more intense eosinophilic infiltration and the presence of Th2 cytokines. Mucosal eosinophilia is associated with more severe symptoms and often requires multiple surgeries because of recurrence; however, even in eosinophilic CRS (ECRS), clinical course is variable. In this study, we wanted to set objective clinical criteria for the diagnosis of refractory CRS.

Treatment of neurological disorders by introducing mRNA in vivo using polyplex nanomicelles.

Sensory nerve disorders are difficult to cure completely considering poor nerve regeneration capacity and difficulties in accurately targeting neural tissues. Administering mRNA is a promising approach for treating neurological disorders because mRNA can provide proteins and peptides in their native forms for mature non-dividing neural cells, without the need of entering their nuclei. However, direct mRNA administration into neural tissues in vivo has been challenging due to too unstable manner of mRNA and its strong immunogenicity. Thus, using a suitable carrier is essential for effective mRNA administration. For this purpose, we established a novel carrier based on the self-assembly of polyethylene glycol (PEG)-polyamino acid block copolymer, i.e. polyplex nanomicelles. To investigate the feasibility and efficacy of mRNA administration for the treatment of sensory nerve disorders, we used a mouse model of experimentally induced olfactory dysfunction. Intranasal administration of mRNA-loaded nanomicelles provided an efficient and sustained protein expression for nearly two days in nasal tissues, particularly in the lamina propria which contains olfactory nerve fibers, with effectively regulating the immunogenicity of mRNA. Consequently, once-daily intranasal administration of brain-derived neurotrophic factor (BDNF)-expressing mRNA using polyplex nanomicelles remarkably enhanced the neurological recovery of olfactory function along with repairing the olfactory epithelium to a nearly normal architecture. To the best of our knowledge, this is the first study to show the therapeutic potential of introducing exogenous mRNA for the treatment of neurological disorders. These results indicate the feasibility and safety of using mRNA, and provide a novel strategy of mRNA-based therapy.

Innate immune responses and neuroepithelial degeneration and regeneration in the mouse olfactory mucosa induced by intranasal administration of Poly(I:C).

The pathogenesis of postviral olfactory disorder (PVOD) has not been fully elucidated. We investigated morphological changes and innate immune responses in the mouse olfactory mucosa induced by intranasal administration of polyinosinic-polycytidylic acid [Poly(I:C)], a synthetic analog of viral double-stranded RNA. Mice received three administrations of saline with or without Poly(I:C), once every 24xa0h. The olfactory mucosa was harvested at various intervals after the first administration (8xa0h, 3, 9 and 24xa0days). In the Poly(I:C) group, the number of apoptotic cells in the olfactory neuroepithelium had increased at 8xa0h. At 9xa0days, the olfactory neuroepithelium had severely degenerated and behavioral tests demonstrated that the mice showed signs of olfactory deterioration. At 24xa0days, the structure of the neuroepithelium had regenerated almost completely. Regarding the innate immune responses, many neutrophils had infiltrated the olfactory neuroepithelium at 8xa0h and had exuded into the nasal cavity by 3xa0days. Macrophages had also infiltrated the olfactory neuroepithelium at 8xa0h although to a lesser extent, but they still remained in the neuroepithelium at 24xa0days. Poly(I:C)-induced neuroepithelial damage was significantly inhibited by a neutrophil elastase inhibitor and was suppressed in neutropenic model mice. These findings suggest that the secondary damage caused by the neutrophil-mediated innate immune response plays an important role in the pathogenesis of PVOD.

Damage to Olfactory Progenitor Cells Is Involved in Cigarette Smoke-Induced Olfactory Dysfunction in Mice.

Exposure to cigarette smoke is a major cause of olfactory dysfunction. However, the underlying mechanisms by which cigarette smoke interferes with the highly regenerative olfactory nerve system remain unclear. To investigate whether cigarette smoke induces olfactory dysfunction by disrupting cell proliferation and cell survival in the olfactory epithelium (OE), we developed a mouse model of smoking that involved intranasal administration of a cigarette smoke solution (CSS). Immunohistological analyses and behavioral testing showed that CSS administration during a period of 24 days reduced the number of olfactory marker protein-positive mature olfactory receptor neurons (ORNs) in the OE and induced olfactory dysfunction. These changes coincided with a reduction in the number of SOX2(+) ORN progenitors and Ki-67(+) proliferating cells in the basal layer of the OE, an increase in the number of caspase-3(+) apoptotic cells, and an increase in the expression of mRNA for the inflammatory cytokines IL-1β and IL-6. Notably, the proliferating ORN progenitor population recovered after cessation of treatment with CSS, resulting in the subsequent restoration of mature ORN numbers and olfaction. These results suggest that SOX2(+) ORN progenitors are targets of CSS-induced impairment of the OE, and that by damaging the ORN progenitor population and increasing ORN death, CSS exposure eventually overwhelms the regenerative capacity of the epithelium, resulting in reduced numbers of mature ORNsxa0and olfactory dysfunction.

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.

Effects of nasal septum perforation repair surgery on three-dimensional airflow: an evaluation using computational fluid dynamics.

The purpose of this research is to determine the cause of nasal perforation symptoms and to predict post-operative function after nasal perforation repair surgery. A realistic three-dimensional (3D) model of the nose with a septal perforation was reconstructed using a computed tomography (CT) scan from a patient with nasal septal defect. The numerical simulation was carried out using ANSYS CFX V13.0. Pre- and post-operative models were compared by their velocity, pressure gradient (PG), wall shear (WS), shear strain rate (SSR) and turbulence kinetic energy in three plains. In the post-operative state, the crossflows had disappeared, and stream lines bound to the olfactory cleft area had appeared. After surgery, almost all of high-shear stress areas were disappeared comparing pre-operative model. In conclusion, the effects of surgery to correct nasal septal perforation were evaluated using a three-dimensional airflow evaluation. Following the surgery, crossflows disappeared, and WS, PG and SSR rate were decreased. A high WS.PG and SSR were suspected as causes of nasal perforation symptoms.

Ethmoidectomy combined with superior meatus enlargement increases olfactory airflow

The relationship between a particular surgical technique in endoscopic sinus surgery (ESS) and airflow changes in the post‐operative olfactory region has not been assessed. The present study aimed to compare olfactory airflow after ESS between conventional ethmoidectomy and ethmoidectomy with superior meatus enlargement, using virtual ESS and computational fluid dynamics (CFD) analysis.

Correlation of basophil infiltration in nasal polyps with the severity of chronic rhinosinusitis

Chronic rhinosinusitis (CRS) represents a heterogeneous disease group characterized by local inflammation of the sinonasal tissues.1 It has been defined as symptomatic inflammation of the sinonasal mucosa that lasts more than 12 weeks as confirmed by computed tomography (CT) and nasal endoscopy.2 Generally, CRS is divided into 2 subsets based on endoscopic findings: CRS with nasal polyps (CRSwNP) and CRS without nasal polyps (CRSsNP).3 In Europe and the United States, eosinophilia is evident in nasal polyps (NPs) from patients with CRSwNP.4 In contrast, heterogeneity of CRSwNP has been reported in East Asian countries, such as Japan, Korea, and China, where the presence and extent of eosinophilia are variable and a significant proportion of NPs do not manifest local eosinophilia.5 Although the pathogenesis of CRS remains controversial, eosinophilic inflammation is considered at least partly responsible. Eosinophilic NPs contain an environment enriched for TH2 cytokines, including interleukin (IL) 4, IL-5, and IL-13.6 TH2 cytokines are believed to contribute to the pathogenesis of eosinophilic CRSwNP, with IL-5 and IL-13 inducing eosinophil recruitment and promoting their activation and IL-4 promoting the switching of the immunoglobulin to the IgE isotype.7 Basophils are reportedly increased in the bronchial submucosa of asthmatic patients and the nasal submucosa of patients with allergic rhinitis.8,9 Research is increasingly addressing the role of basophils in inducing TH2-type responses.10 Although CRSwNP is a highly TH2-biased disease, making the involvement of basophils likely, there are few reports of the involvement of basophils in CRS.11

Viral disruption of olfactory progenitors is exacerbated in allergic mice

Upper airway viral infection in patients with airway allergy often exacerbates olfactory dysfunction, but the mechanism for this exacerbation remains unclear. Here, we examined the effects of respiratory syncytial virus (RSV) infection, in the presence or absence of airway allergy, on olfactory receptor neurons (ORNs) and their progenitors in mice. Immunohistological analyses revealed that cockroach allergen (CRA)-induced airway allergy alone did not affect the number of OMP(+) mature ORNs and SOX2(+) ORN progenitors. Intranasal RSV line 19 infection in allergy-free mice resulted in a transient decrease in SOX2(+) ORN progenitors without affecting OMP(+) ORNs. In contrast, the RSV-induced decrease in SOX2(+) ORN progenitors was exacerbated and prolonged in allergic mice, which resulted in eventual loss of OMP(+) ORNs. In the allergic mice, reduction of RSV in the olfactory epithelium was delayed as compared with allergy-free mice. These results suggest that ORN progenitors were impaired by RSV infection and that airway allergy exacerbated damage to ORN progenitors by reducing viral clearance.