NRP1 antagonism as a novel therapeutic target in nasal polyps of patients with chronic rhinosinusitis.

BACKGROUND: Neuropilin-1 (NRP1) is expressed on the surface epithelium of respiratory tract and immune cells, demonstrating its possible function in regulating the immune response in airway disease. However, its role in patient with chronic rhinosinusitis (CRS) remains unknown. This study aimed to elucidate the role of NRP1 in CRS with nasal polyps (CRSwNP). METHODS: Sinonasal biopsy specimens were immunohistochemically stained to investigate NRP1 expression. Double immunofluorescence, immunoblotting, and real-time polymerase chain reaction were performed to evaluate NRP1 in primary human nasal epithelial cells (hNECs). An NRP1 inhibitor was administered to a murine nasal polyp (NP) model. RESULTS: NRP1 was highly expressed in the epithelium in patients with CRSwNP compared to nasal tissue from controls and CRS without NP patients. NRP1 and vascular endothelial growth factor were upregulated in hNECs under hypoxia. Treatment with NRP1 inhibitor (EG00229) reduced the secretion of interleukin (IL)-1ß, IL-6, IL-8, and IL-33 cytokines, as well as inducible nitric oxide synthase, cyclooxygenase-2, and prostaglandin E2 in hNECs. We found that NRP1 was highly expressed in the airway epithelium in the murine NP model. The group treated with the NRP1 inhibitor had significantly fewer nasal polypoid lesions and reduced accumulations of immune cells. CONCLUSIONS: These findings reveal that NRP1 is upregulated in CRS and NP epithelium, and the inhibition of NRP1 may lead to a reduction in NP growth and immune cell infiltration. Our results suggest that NRP1 inhibition could be a novel possibility for treating nasal polyposis.

Neutrophil extracellular traps promote ΔNp63+ basal cell hyperplasia in chronic rhinosinusitis.

BACKGROUND: Neutrophil extracellular traps (NETs) are observed in chronic rhinosinusitis (CRS), although their role remains unclear. OBJECTIVES: This study aimed to investigate the influence of NETs on the CRS epithelium. METHODS: Forty-five sinonasal biopsy specimens were immunofluorescence-stained to identify NETs and p63+ basal stem cells. Investigators treated human nasal epithelial cells with NETs and studied them with immunofluorescence staining, Western blotting, and quantitative real-time PCR. NET inhibitors were administered to a murine neutrophilic nasal polyp model. RESULTS: NETs existed in tissues in patients with CRS with nasal polyps, especially in noneosinophilic nasal polyp tissues. p63+ basal cell expression had a positive correlation with the release of NETs. NETs induced the expansion of Ki-67+p63+ cells. We found that ΔNp63, an isoform of p63, was mainly expressed in the nasal epithelium and controlled by NETs. Treatment with deoxyribonuclease (DNase) I or Sivelestat (NET inhibitors) prevented the overexpression of ΔNp63+ epithelial stem cells and reduced polyp formation. CONCLUSIONS: These results reveal that NETs are implicated in CRS pathogenesis via basal cell hyperplasia. This study suggests a novel possibility of treating CRS by targeting NETs.

DEP-induced ZEB2 promotes nasal polyp formation via epithelial-to-mesenchymal transition.

BACKGROUND: Diesel exhaust particles (DEPs) are associated with the prevalence and exacerbation of allergic respiratory diseases, including allergic rhinitis and allergic asthma. However, DEP-induced mechanistic pathways promoting upper airway disease and their clinical implications remain unclear. OBJECTIVE: We sought to investigate the mechanisms by which DEP exposure contributes to nasal polyposis using human-derived epithelial cells and a murine nasal polyp (NP) model. METHODS: Gene set enrichment and weighted gene coexpression network analyses were performed. Cytotoxicity, epithelial-to-mesenchymal transition (EMT) markers, and nasal polyposis were assessed. Effects of DEP exposure on EMT were determined using epithelial cells from normal people or patients with chronic rhinosinusitis with or without NPs. BALB/c mice were exposed to DEP through either a nose-only exposure system or nasal instillation, with or without house dust mite, followed by zinc finger E-box-binding homeobox (ZEB)2 small hairpin RNA delivery. RESULTS: Bioinformatics analyses revealed that DEP exposure triggered EMT features in airway epithelial cells. Similarly, DEP-exposed human nasal epithelial cells exhibited EMT characteristics, which were dependent on ZEB2 expression. Human nasal epithelial cells derived from patients with chronic rhinosinusitis presented more prominent EMT features after DEP treatment, when compared with those from control subjects and patients with NPs. Coexposure to DEP and house dust mite synergistically increased the number of NPs, epithelial disruptions, and ZEB2 expression. Most importantly, ZEB2 inhibition prevented DEP-induced EMT, thereby alleviating NP formation in mice. CONCLUSIONS: Our data show that DEP facilitated NP formation, possibly via the promotion of ZEB2-induced EMT. ZEB2 may be a therapeutic target for DEP-induced epithelial damage and related airway diseases, including NPs.

Bone morphogenetic protein-2 as a novel biomarker for refractory chronic rhinosinusitis with nasal polyps.

BACKGROUND: Bone morphogenetic proteins (BMPs), which are members of the TGF-ß superfamily, regulate bone remodeling by stimulating osteoblasts and osteoclasts. Although the association between osteitis and poor surgical outcomes is well known in patients with chronic rhinosinusitis (CRS), BMPs have not been fully investigated as potential biomarkers for the prognosis of CRS. OBJECTIVE: Our aim was to investigate the role of BMPs in osteitis in patients with CRS with nasal polyps (NPs) (CRSwNPs), as well as associations between BMPs and inflammatory markers in sinonasal tissues from patients with CRSwNP. METHODS: We investigated the expression of 6 BMPs (BMP-2, BMP-4, BMP-6, BMP-7, BMP-9, and BMP-10) and their cellular origins in NPs of human subjects by using immunohistochemistry and ELISA of NP tissues. Exploratory factor analysis was performed to identify associations between BMPs and inflammatory markers. Air-liquid interface cell culture of human nasal epithelial cells was performed to evaluate the induction of the epithelial-mesenchymal transition by BMPs. RESULTS: Of the 6 BMPs studied, BMP-2 and BMP-7 were associated with refractoriness. Only BMP-2 concentrations were higher in patients with severe osteitis and advanced disease extent according to the computed tomography findings. Eosinophils and some macrophages were identified as cellular sources of BMP-2 in immunofluorescence analysis. An in vitro experiment revealed that BMP-2 induced epithelial-mesenchymal transition in air-liquid interface-cultured human nasal epithelial cells, particularly in a TH2 milieu. CONCLUSION: BMP-2 could reflect the pathophysiology of mucosa and bone remodeling and may be a novel biomarker for refractory CRSwNP.

Effect of lipopolysaccharide and polyinosinic:polycytidylic acid in a murine model of nasal polyp.

Several factors, including bacterial and viral infections, have been associated with rhinosinusitis and nasal tissue remodelling that may result in nasal polyp formation. However, the potential role of bacterial or viral stimuli triggering polyp development is unclear. Here, we used lipopolysaccharide (LPS) and polyinosinic:polycytidylic acid [poly(I:C)] in a murine model of allergic rhinosinusitis to compare different effects of bacterial- and virus-derived stimuli in the pathogenesis of nasal polyp formation. Briefly, BALB/c mice were sensitised and challenged with ovalbumin and staphylococcal enterotoxin, with or without LPS or poly(I:C), and the consequent histopathological profiles, cytokines, and systemic humoral responses were studied. While no significant differences in polyp formations and epithelial disruptions were observed among the experimental groups, the local cell recruitment patterns slightly differed in animals that received either LPS or poly(I:C). Additionally, the local immune environments generated by LPS or poly(I:C) stimulation varied. LPS stimulation induced a marked Th1/Th17 response and predominantly neutrophilic nasal polyp formations, whereas poly(I:C) induced a Th2-skewed environment in neutrophilic nasal polyp development. Overall, our findings show that both cell recruitment patterns and local immune environments induced by these two stimuli differ, which may have implications in the physiopathology of rhinosinusitis with nasal polyp.

Crosstalk Between Mucosal Inflammation and Bone Metabolism in Chronic Rhinosinusitis.

Chronic rhinosinusitis (CRS) is a multifactorial and highly heterogeneous upper airway disease that affects approximately 12% of the general population. There is increasing evidence supporting the impact of osteitis on the pathophysiology of CRS. Osteitis is frequently observed in patients with CRS, and is associated with severe sinonasal inflammation and recalcitrant cases. The overlying inflammatory sinonasal mucosa plays a critical role in the initiation of osteitis; however, the underlying molecular mechanisms and functional significance remain unclear. Increasingly many studies have suggested that immune cells play a crucial role in the bone remodeling process in CRS. The purpose of this review is to summarize the current state of knowledge regarding the specific role of sinonasal inflammation in bone remodeling in CRS patients.

Evaluation of Neo-Osteogenesis in Eosinophilic Chronic Rhinosinusitis Using a Nasal Polyp Murine Model.

PURPOSE: Osteitis refers to the development of new bone formation and remodeling of bone in chronic rhinosinusitis (CRS) patients; it is typically associated with eosinophilia, nasal polyps (NPs), and recalcitrant CRS. However, the roles of ossification in CRS with or without NPs remain unclear due to the lack of appropriate animal models. Thus, it is necessary to have a suitable animal model for greater advances in the understanding of CRS pathogenesis. METHODS: BALB/c mice were administered ovalbumin (OVA) and staphylococcal enterotoxin B (SEB). The numbers of osteoclasts and osteoblasts and bony changes were assessed. Micro computed tomography (micro-CT) scans were conducted to measure bone thickness. Immunofluorescence, immunohistochemistry, and quantitative polymerase chain reaction were performed to evaluate runt-related transcription factor 2 (RUNX2), osteonectin, interleukin (IL)-13, and RUNX2 downstream gene expression. Gene set enrichment analysis was performed in mucosal tissues from control and CRS patients. The effect of resveratrol was evaluated in terms of osteogenesis in a murine eosinophilic CRS NP model. RESULTS: The histopathologic changes showed markedly thickened bones with significant increase in osteoblast numbers in OVA/SEB-treated mice compared to the phosphate-buffered saline-treated mice. The structural changes in bone on micro-CT were consistent with the histopathological features. The expression of RUNX2 and IL-13 was increased by the administration of OVA/SEB and showed a positive correlation. RUNX2 expression mainly co-localized with osteoblasts. Bioinformatic analysis using human CRS transcriptome revealed that IL-13-induced bony changes via RUNX2. Treatment with resveratrol, a candidate drug against osteitis, diminished the expression of IL-13 and RUNX2, and the number of osteoblasts in OVA/SEB-treated mice. CONCLUSIONS: In the present study, we found the histopathological and radiographic evidence of osteogenesis using a previously established murine eosinophilic CRS NP model. This animal model could provide new insights into the pathophysiology of neo-osteogenesis and provide a basis for developing new therapeutics.

Superantigen-related TH2 CD4+ T cells in nonasthmatic chronic rhinosinusitis with nasal polyps.

BACKGROUND: Staphylococcus aureus enterotoxin (SAE) superantigens are detected in nasal polyps (NPs), and SAE-specific IgE predicts asthma comorbidity in patients with NPs. However, roles of SAE superantigens and superantigen-related T-cell responses remain to be elucidated in nonasthmatic patients. OBJECTIVE: We investigated the presence of SAEs and SAE-related T-cell receptor (TCR) Vß (TCRVß) in nonasthmatic NPs, the phenotypes and functions of SAE-related T cells, and the clinical implication of SAE-related T-cell expansion. METHODS: Sinonasal tissue samples were obtained from patients with nonasthmatic chronic rhinosinusitis (CRS) with NPs (CRSwNP), patients with CRS without NPs (CRSsNP), and control subjects. SAE genes were detected by PCR, and the TCRVß distribution and T-cell phenotypes were examined by flow cytometry. RESULTS: Various SAE genes were detected not only in NPs but also in sinonasal mucosa from patients with CRSsNP and from controls. The S aureus enterotoxin I (SEI) gene was detected in all NPs. The fraction of SEI-responsive TCRVß+ (TCRVß1+ and Vß5.1+) CD4+ T cells was significantly increased only in NPs and the ethmoidal mucosa of patients with CRSwNP, indicating superantigen-induced expansion. The expanded TCRVß5.1+ CD4+ T cells expressed proliferation marker Ki-67 and the TH2 transcription factor GATA3. Furthermore, TCRVß5.1+ CD4+ T cells in NPs highly expressed TH2 markers, including IL-17RB, thymic stromal lymphoprotein receptor, and chemoattractant receptor-homologous molecule expressed on TH2 cells, with a potent TH2 cytokine-producing ability. Moreover, the expansion of TCRVß1+ or Vß5.1+ CD4+ T cells was associated with the Lund-Mackay computed tomography score, indicating disease extent. CONCLUSION: In nonasthmatic patients with CRSwNP, superantigen-related expansion of CD4+ T cells with TH2 differentiation was associated with the disease extent.

α-Helical cell-penetrating peptide-mediated nasal delivery of resveratrol for inhibition of epithelial-to-mesenchymal transition.

In the present study, we examined the potential of cell-penetrating peptide (CPP)-based intranasal drug delivery for the treatment of localized nasal diseases. Many charged or non-hydrophobic drugs have difficulty penetrating into the nasal epithelium due to intrinsic membrane impermeability and rapid mucociliary clearance in the nasal cavity. To treat chronic rhinosinusitis with nasal polyps (CRSwNP), one of the most common localized nasal diseases, we conjugated resveratrol (RSV) to an amphiphilic α-helical leucine (L)- and lysine (K)-rich CPP (LK) and intranasally delivered it to the interior of nasal epithelial cells for inhibiting epithelial-to-mesenchymal transition (EMT) caused by hypoxia-inducible factor 1α. The RSV-LK conjugate could penetrate into the nasal epithelium and efficiently inhibit EMT, nasal polyp formation, epithelial disruption, and related inflammation in an eosinophilic CRSwNP mouse model, at 10-fold lower doses and with 3-fold less frequent administration than free RSV. Due to the rapid penetration into the nasal epithelium and the therapeutic effect of the RSV-LK conjugate at much lower doses than free RSV, this CPP-based delivery system, with the ability to overcome the tight nasal epithelial barrier, may provide a new strategy for the treatment of localized nasal diseases without the systemic side effects of cargo drugs.

Interleukin (IL)-13 and IL-17A contribute to neo-osteogenesis in chronic rhinosinusitis by inducing RUNX2.

BACKGROUND: There is increasing evidence supporting the impact of neoosteogenesis in the pathophysiology of chronic rhinosinusitis (CRS), especially in the recalcitrant group of patients. Runt-related transcription factor 2 (RUNX2), a member of the RUNX family, controls osteoblast differentiation and bone formation. However, the role and regulation of RUNX2 in CRS patients with neoosteogenesis remain unclear. The aim of the study is to determine the role of RUNX2 in neoosteogenesis of CRS patients. METHODS: Sinonasal bone and overlying mucosa samples were obtained from CRS patients with or without neoosteogenesis (n = 67) and healthy controls (n = 11). Double immunofluorescence, immunohistochemistry, and immunoblotting were used to evaluate RUNX2 expression in CRS patients with and without neoosteogenesis. In addition, the osteogenic activity of pro-inflammatory cytokines was examined by measuring alkaline phosphatase (ALP) activity and bone mineralisation in vitro. FINDINGS: RUNX2 was highly expressed in osteoblasts of CRS patients with neoosteogenesis compared with tissues from control subjects and those with CRS without neoosteogenesis. Mucosal extracts from CRS patients with neoosteogenesis showed increased RUNX2 expression and ALP activity in C2C12 cells, whereas those from patients without neoosteogenesis did not. Expression of interleukin (IL)-13 and IL-17A was upregulated in CRS patients with neoosteogenesis. ALP activity and Alizarin Red staining showed IL-13 and IL-17A dose-dependent osteoblast differentiation and mineralisation in vitro. INTERPRETATION: These findings suggested that IL-13- or IL-17A-induced RUNX2 contributed to new bone formation in CRS patients through its effect on the activity of osteoblasts. RUNX2 may be a novel target for preventing neoosteogenesis in CRS patients.

The IFN-γ-p38, ERK kinase axis exacerbates neutrophilic chronic rhinosinusitis by inducing the epithelial-to-mesenchymal transition.

Chronic rhinosinusitis (CRS) is a heterogeneous and multifactorial inflammatory disease characterized by involvement of diverse types of inflammatory cells. Asian CRS patients frequently show infiltration of neutrophils and an elevated level of interferon (IFN)-γ; by contrast, western patients exhibit eosinophil infiltration and enhanced levels of Th2-related cytokines. Neutrophilia in tissues decreases sensitivity to corticosteroids, but the mechanisms underlying the progression of neutrophilic CRS are unclear. In this study, we investigated the role of IFN-γ in CRS patients with marked neutrophil infiltration. We report that the IFN-γ level is upregulated in the tissues of these patients, particularly those with non-eosinophilic nasal polyps. The level of IFN-γ was significantly correlated with markers of the epithelial-to-mesenchymal transition (EMT). We further demonstrated that IFN-γ induced the EMT via the p38 and extracellular signal-regulated kinase (ERK) pathways in a manner distinct from the hypoxia-inducible factor (HIF)-1α, SMAD, and NF-κB signaling pathways. In a murine nasal polyp (NP) model, blocking the p38 and ERK signaling pathways prevented NP formation and chemotactic cytokine secretion by neutrophils but not eosinophils. Taken together, our results suggest that IFN-γ can induce the EMT in nasal epithelial cells, and thus blocking the p38 and ERK pathways could be an effective therapeutic strategy against neutrophil-dominant CRS.

Intermittent hypoxia promotes carcinogenesis in azoxymethane and dextran sodium sulfate-induced colon cancer model.

Intermittent hypoxia (IH), a characteristic of obstructive sleep apnea, is known to promote cancer progression and aggressiveness in mouse models. However, little is known regarding the effect of IH on cancer initiation. Here, the effect of IH on carcinogenesis was explored in azoxymethane (AOM) and dextran sodium sulfate (DSS)-induced colon cancer models with three different protocols. In the first protocol, two other application time points (early or late initiation of IH) were applied. In the second protocol, mice were divided into only two groups, and then exposed to either N or IH conditions for 14 days. In the third protocol, a pharmacological inhibition study for anti-inflammation (5-aminosalicylate) or anti-oxidative stress (N-acetylcysteine [NAC]) was performed. The number of tumors was significantly higher in the IH-1 than in the N or IH-2 groups. 8-oxo-2'-deoxyguanosine (8-OHdG) levels were higher in tumors of the IH-1 group than in that of the N and IH-2 groups. Gene expression related to reactive oxygen species production was higher in the IH-1 group than in the N and IH-2 groups, and it showed a positive correlation with 8-OHdG levels. Prior to cancer development 8-OHdG levels were already elevated in colonic epithelial regions in the IH group, possibly due to an imbalance between oxidative stress and antioxidant systems. NAC treatment resulted in a significant reduction in the number of tumors in mice exposed to IH. In conclusion, IH promotes carcinogenesis in a chemically-induced colon cancer model where elevated 8-OHdG may contribute to the increased tumor induction.

Wogonin attenuates nasal polyp formation by inducing eosinophil apoptosis through HIF-1α and survivin suppression.

Chronic rhinosinusitis (CRS) with nasal polyps (CRSwNP) is an inflammatory sinonasal disorder characterized by eosinophilic inflammation and T-helper 2 skewing. Eosinophil accumulation in sinonasal mucosa comprises a major feature of CRSwNP. The study aimed to investigate the effect of the flavone wogonin in nasal polyposis by assessing its ability to induce eosinophil apoptosis in vitro and attenuate eosinophilic CRSwNP in mice. Double immunofluorescence, immunohistochemistry, flow cytometry, and immunoblotting were performed to evaluate hypoxia-inducible factor (HIF)-1α, survivin, and apoptotic markers in the human eosinophilic EoL-1 cell line or sinonasal tissues from patients with CRS with or without NPs. In sinonasal specimens from patients with CRS, HIF-1α and survivin were up-regulated in eosinophils from patients with NPs compared with levels in patients without NPs. Under hypoxia, HIF-1α and survivin expression was up-regulated in EoL-1 cells. Wogonin down-regulated both HIF-1α and survivin in EoL-1 cells. In addition, overexpression of survivin protected EoL-1 cells against apoptosis in response to wogonin. Moreover, wogonin attenuated nasal polyp formation in a murine model. Our findings suggest that wogonin could induce caspase-3 activation by suppressing HIF-1α and survivin expression in EoL-1 cells. Further studies regarding novel therapeutic options for CRSwNP targeting eosinophil apoptosis are needed.

Fibrinogen cleavage products and Toll-like receptor 4 promote the generation of programmed cell death 1 ligand 2-positive dendritic cells in allergic asthma.

BACKGROUND: Inhaled protease allergens preferentially trigger TH2-mediated inflammation in allergic asthma. The role of dendritic cells (DCs) on induction of TH2 cell responses in allergic asthma has been well documented; however, the mechanism by which protease allergens induce TH2-favorable DCs in the airway remains unclear. OBJECTIVE: We sought to determine a subset of DCs responsible for TH2 cell responses in allergic asthma and the mechanism by which protease allergens induce the DC subset in the airway. METHODS: Mice were challenged intranasally with protease allergens or fibrinogen cleavage products (FCPs) to induce allergic airway inflammation. DCs isolated from mediastinal lymph nodes were analyzed for surface phenotype and T-cell stimulatory function. Anti-Thy1.2 and Mas-TRECK mice were used to deplete innate lymphoid cells and mast cells, respectively. Adoptive cell transfer, bone marrow DC culture, anti-IL-13, and Toll-like receptor (TLR) 4-deficient mice were used for further mechanistic studies. RESULTS: Protease allergens induced a remarkable accumulation of TH2-favorable programmed cell death 1 ligand 2 (PD-L2)+ DCs in mediastinal lymph nodes, which was significantly abolished in mice depleted of mast cells and, to a lesser extent, innate lymphoid cells. Mechanistically, FCPs generated by protease allergens triggered IL-13 production from wild-type mast cells but not from TLR4-deficient mast cells, which resulted in an increase in the number of PD-L2+ DCs. Intranasal administration of FCPs induced an increase in numbers of PD-L2+ DCs in the airway, which was significantly abolished in TLR4- and mast cell-deficient mice. Injection of IL-13 restored the PD-L2+ DC population in mice lacking mast cells. CONCLUSION: Our findings unveil the "protease-FCP-TLR4-mast cell-IL-13" axis as a molecular mechanism for generation of TH2-favorable PD-L2+ DCs in allergic asthma and suggest that targeting the PD-L2+ DC pathway might be effective in suppressing allergic T-cell responses in the airway.

Accelerated tumor growth under intermittent hypoxia is associated with hypoxia-inducible factor-1-dependent adaptive responses to hypoxia.

Mounting evidence has revealed a causative role of intermittent hypoxia (IH) in cancer progression in mouse models of obstructive sleep apnea (OSA), but most studies have focused on the effects of IH following tumor implantation using an exposure to single IH frequency. Thus, we aimed to investigate 1) the potential effect of IH on the initial tumor growth in patients with OSA without an interaction with other mechanisms induced by IH in mice and 2) the influence of the IH frequency on tumor growth, which were tested using pre-conditioning with IH (Pre-IH) and 2 different IH frequencies, respectively. Pre-IH was achieved by alternatively maintaining melanoma cells between normoxia (10 min, 21% O2) and hypoxia (50 min, 1% O2) for 7 days (12 cycles per day) before administering them to mice. The conditions for IH-1 and IH-2 were 90 s of 12% FiO2 followed by 270s of 21% FiO2 (10 cycles/h), and 90 s of 12% FiO2 and 90 s of 21% FiO2 (20 cycles/h), respectively, for 8 h per day. Tumor growth was significantly higher in the Pre-IH group than in the normoxia group. In addition, the IH-2 group showed more accelerated tumor growth compared to the normoxia and IH-1 groups. Immunohistochemistry and gene-expression results consistently showed the up-regulation of molecules associated with HIF-1α-dependent hypoxic adaptation in tumors of the Pre-IH and IH-2 groups. Our findings reveal that IH increased tumor progression in a frequency-dependent manner, regardless of whether it was introduced before or after in vivo tumor cell implantation.

Immune Cell Responses and Mucosal Barrier Disruptions in Chronic Rhinosinusitis.

Chronic rhinosinusitis (CRS) is one of the most common presentations of upper airway illness and severely affects patient quality of life. Its frequency is not surprising given levels of environmental exposure to microbes, pollutants, and allergens. Inflammatory cells, inflammatory cytokine and chemokine production, and airway remodeling have been detected in the sinonasal mucosae of CRS patients, although the precise pathophysiological mechanisms causing such persistent inflammation remain unclear. Given its high prevalence and considerable associated morbidity, continued research into CRS is necessary to increase our understanding of factors likely to contribute to its pathogenesis, and facilitate the development of novel therapeutic strategies to improve treatment. The purpose of this review is to summarize the current state of knowledge regarding immune cell responses and epithelial alterations in CRS.

Sinonasal Delivery of Resveratrol via Mucoadhesive Nanostructured Microparticles in a Nasal Polyp Mouse Model.

Resveratrol (RSV) has been shown to effectively suppress chronic rhinosinusitis with nasal polyps in a mouse model; however, when locally administered to the sinonasal cavity, bolus RSV is limited by low drug bioavailability owing to its low aqueous solubility and relatively rapid clearance from the administration site. To address this limitation, we propose mucoadhesive nanostructured microparticles (PLGA/PEG NM) as a potential carrier for the sinonasal delivery of RSV. In this study, PLGA/PEG NM released RSV in a sustained manner. Owing to the enlarged specific surface area of the nanostructures, PLGA/PEG NM had synergistically enhanced mucoadhesiveness and thus showed improved in vivo retention properties in the sinonasal cavity. Therefore, when tested in a mouse nasal polyp model, PLGA/PEG NM mitigated polyp formation and restored epithelial integrity better than the control treatments. The therapeutic effect was similar at half the dose of PLGA/PEG NM, suggesting improved local bioavailability of RSV in the sinonasal cavity.

Serial Analysis of Tracheal Restenosis After 3D-Printed Scaffold Implantation: Recruited Inflammatory Cells and Associated Tissue Changes.

Tracheal restenosis is a major obstacle to successful tracheal replacement, and remains the greatest challenge in tracheal regeneration. However, there have been no detailed investigations of restenosis. The present study was performed to analyze the serial changes in recruited inflammatory cells and associated histological changes after tracheal scaffold implantation. Asymmetrically porous scaffolds, which successfully prevented tracheal stenosis in a partial trachea defect model, designed with a tubular shape by electrospinning and reinforced by 3D-printing to reconstruct 2-cm circumferential tracheal defect. Serial rigid bronchoscopy, micro-computed tomography, and histology [H&E, Masson's Trichrome, IHC against α-smooth muscle actin (α-SMA)] were performed 1, 4, and 8 weeks after transplantation. Progressive stenosis developed especially at the site of anastomosis. Neutrophils were the main inflammatory cells recruited in the early stage, while macrophage infiltration increased with time. Recruitment of fibroblasts peaked at 4 weeks and deposition of α-SMA increased from 4 weeks and was maintained through 8 weeks. During the first 8 weeks post-transplantation, neutrophils and macrophages played significant roles in restenosis of the trachea. Antagonists to these would be ideal targets to reduce restenosis and thus play a pivotal role in successful tracheal regeneration.