Animal Models in CRS and Pathophysiologic Insights Gained: A Systematic Review

Akt activator SC79 stimulates antibacterial nitric oxide generation in human nasal epithelial cells in vitro

BACKGROUND

The role of Akt in nasal immunity is unstudied. Akt phosphorylates and activates endothelial nitric oxide synthase (eNOS) expressed in epithelial ciliated cells. Nitric oxide (NO) production by ciliated cells can have antibacterial and antiviral effects. Increasing nasal NO may be a useful antipathogen strategy in chronic rhinosinusitis (CRS). We previously showed that small-molecule Akt activator SC79 induces nasal cell NO production and suppresses IL-8 via the transcription factor Nrf-2. We hypothesized that SC79 NO production may additionally have antibacterial effects.

METHODS

NO production was measured using fluorescent dye DAF-FM. We tested effects of SC79 during co-culture of Pseudomonas aeruginosa with primary nasal epithelial cells, using CFU counting and live-dead staining to quantify bacterial killing. Pharmacology determined the mechanism of SC79-induced NO production and tested dependence on Akt.

RESULTS

SC79 induced dose-dependent, Akt-dependent NO production in nasal epithelial cells. The NO production required eNOS and Akt. The NO released into the airway surface liquid killed P. aeruginosa. No toxicity (LDH release) or inflammatory effects (IL8 transcription) were observed over 24 h.

CONCLUSIONS

Together, these data suggest multiple immune pathways are stimulated by SC79, with antipathogen effects. This in vitro pilot study suggests that a small-molecule Akt activator may have clinical utility in CRS or respiratory other infection settings, warranting future in vivo studies.

Which are the best murine models to study Eosinophilic Chronic Rhinosinusitis? A contemporary review

OBJECTIVE

Mechanisms that lead to Eosinophilic Chronic Rhinosinusitis (ECRS) are not fully established in the literature. It is desirable to assess ECRS in a model that embraces most of the related events. This article reviewed the murine models for ECRS and compared them regarding eosinophilic polypoid formation.

METHODS

The authors reviewed the articles that included the terms "chronic rhinosinusitis" OR "chronic sinusitis" AND "animal model". We analyzed articles in English that evaluated both the number of polyps and the number of eosinophils in the sinus mucosa of mouse models.

RESULTS

We identified a total of 15 articles describing different models of ECRS that used BALB/c or C57BL/6 mice, and different triggers/stimulants such as Staphylococcus aureus Enterotoxin B (SEB) + Ovalbumin (OVA); House Dust Mite (HDM) ± Ovalbumin (OVA); and Aspergillus oryzae Protease (AP) + Ovalbumin (OVA). OVA associated with SEB was the commonest protocol to induce ECRS in both BALB/c and C57BL/6 mice, and it produced a robust response of eosinophilic nasal polyps in both. AP + OVA protocol also led to a good ECRS response. The other models were not considered adequate to produce eosinophilic polyps in mice.

CONCLUSION

In conclusion, OVA associated with SEB seems to produce the most robust eosinophilic sinonasal inflammation.

Nanotechnology-enabled topical delivery of therapeutics in chronic rhinosinusitis

Chronic rhinosinusitis (CRS) is a chronic inflammatory disease of the paranasal sinuses which represents a significant health burden due to its widespread prevalence and impact on patients' quality of life. As the molecular pathways driving and sustaining inflammation in CRS become better elucidated, the diversity of treatment options is likely to widen significantly. Nanotechnology offers several tools to enhance the effectiveness of topical therapies, which has been limited by factors such as poor drug retention, mucosal permeation and adhesion, removal by epithelial efflux pumps and the inability to effectively penetrate biofilms. In this review, we highlight the successful application of nanomedicine in the field of CRS therapeutics, discuss current limitations and propose opportunities for future work.

Lipopolysaccharide-Initiated Rhinosinusitis Causes Neuroinflammation and Olfactory Dysfunction in Mice

Background

Olfactory dysfunction is a common disease and it may be caused by sinonasal inflammation, toxin inhalation, or neurological disorders. After sinonasal inflammation, if both olfactory neuroinflammation and olfactory dysfunction occur still under investigation.

Objective

This study aimed to investigate whether neuroinflammation and olfactory dysfunction occur after lipopolysaccharide (LPS)-initiated rhinosinusitis.

Methods

Adult C57BL/6 mice were intranasally administered with LPS for 3 weeks. The olfactory function was evaluated with a buried food test. The inflammatory status of sinonasal cavity and olfactory bulb was evaluated with histology and biochemistry.

Results

After 3-week LPS treatment, mice developed olfactory dysfunction, sinonasal cavity, and olfactory bulb inflammation. LPS-treated mice had greater sinonasal mucosal thickness. Besides, pro-inflammatory interleukin-6, the number of goblet cells and neutrophils in the sinonasal cavity was increased after LPS administration. The olfactory sensory neurons in the olfactory epithelium and the olfactory bulb were decreased, and the olfactory function was impaired by LPS administration. Inflammatory cytokines such as interferon-γ and tumor necrosis factor-α were increased in the olfactory bulb.

Conclusion

This study showed that LPS-initiated rhinosinusitis caused olfactory neuroinflammation and olfactory dysfunction in mice.

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.

Unilateral Intervention in the Sinuses of Rabbits Induces Bilateral Inflammatory and Microbial Changes

Background

Chronic rhinosinusitis (CRS) is a globally prevalent inflammatory condition of the paranasal sinuses which severely impairs patients' quality of life. An animal model of unilateral sinusitis by transient sinus occlusion has been described previously in rabbits. The aim of this study was to characterise the sinusitis rabbit model by investigating temporal and bilateral changes in the bacterial community and mucosal inflammation.

Methods

Development of sinusitis was achieved by endoscopically placing Merocel ^® , a sterile nasal packing material, in the left middle meatus of six New Zealand white rabbits for four weeks. After a total period of 14 weeks, rabbits were assessed for sinusitis by endoscopic examination, magnetic resonance imaging (MRI) and histology. Swabs from the left and right middle meatus were obtained for bacterial community analysis at three time points (week 0, week 4, week 14) during the study.

Results

Endoscopic evaluation showed unilateral inflammation in all animals examined after the 4-week blocking period and at week 14. Notably, inflammatory changes were also seen in the contralateral sinus of all animals at week 4. MRI images demonstrated unilateral sinus opacification at week 4 in two rabbits, and partial unilateral sinus opacification at week 14 in one rabbit only. Histological analyses revealed substantial spatial heterogeneity of mucosal inflammation with inconsistent findings across all animals. No significant differences in mucosal inflammatory markers (such as goblet cell hyperplasia, epithelial denudation and oedema) could be identified between nostrils at week 14. The bacterial community in the rabbit sinuses was heavily dominated by Helicobacter at week 0 (baseline). At the end of the blocking period (week 4), bacterial alpha and beta diversity were significantly increased in both nostrils. The bacterial community composition at week 14 had primarily returned to baseline, reflecting the endoscopic and radiological results.

Conclusion

This study reaffirmed the ability for development of sinusitis without inoculation of any pathogens in a rabbit model. We were able to demonstrate bilateral sinonasal mucosal inflammation, by inducing unilateral sinus blockage, which resulted in significant changes to the sinonasal bacterial community. These findings may explain some of the clinical observations seen in CRS and warrant further research to reveal potential implications for its therapeutic management.

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.

Interleukin-17A Expression Correlated with the Prognosis of Chronic Rhinosinusitis with Nasal Polyps and the Anti-Interleukin-17A Effect in a Murine Nasal Polyps Model

OBJECTIVE

To investigate the expression of interleukin-17A (IL-17A) in patients with chronic rhinosinusitis with nasal polyps (CRSwNP) and to analyze its effect on prognosis and to explore the role and mechanism of anti-IL-17A effect in vivo by establishing a murine nasal polyps (NP) model.

METHODS

Patients with CRSwNP who underwent endoscopic sinus surgery and matched control subjects were collected. We investigated IL-17A expression in human NP tissues using immunohistochemistry and analyzed their clinical features, including Lund-Mackay computed tomography scoring (LMCS) before surgery, Lund-Kennedy endoscopic scoring (LKES) before surgery (LKES B), LKES 6 months after surgery (LKES A), and reduction of LKES (LKES R). Then, after establishing the murine NP model to detect the expression and correlation of IL-17A and matrix metalloproteinase-9 (MMP-9) in nasal tissue, we studied nasal lavage fluid and serum by PCR and enzyme-linked immunosorbent assay in vivo. Anti-IL-17A treatment was administered in the murine NP model to confirm the function of IL-17A during the pathogenic processes.

RESULTS

IL-17A expression was upregulated in NP tissues from patients with CRSwNP compared with control subjects (p < 0.001). The number of IL-17A+ cells was significantly negatively correlated with LKES R in patients with CRSwNP (p < 0.01). However, there was no significant correlation between IL-17A and LMCS or LKES B (all p < 0.05). Further, IL-17A and MMP-9 were more abundant in nasal mucosa of the murine NP model compared with that of control mice (all p < 0.05), and severe polypoid lesions were apparently observed in murine NP models. Anti-IL-17A treatment downregulated the mRNA and protein expression of MMP-9 in nasal mucosa and reduced the number of polypoid lesions in the murine NP model (all p < 0.05).

CONCLUSION

Our results suggest that IL-17A plays a crucial role and may affect the prognosis of CRSwNP. Anti-IL-17A treatment may reduce the formation of polypoid lesions through inhibition of MMP-9 expression.

Respiratory Viral Infections in Exacerbation of Chronic Airway Inflammatory Diseases: Novel Mechanisms and Insights From the Upper Airway Epithelium

Respiratory virus infection is one of the major sources of exacerbation of chronic airway inflammatory diseases. These exacerbations are associated with high morbidity and even mortality worldwide. The current understanding on viral-induced exacerbations is that viral infection increases airway inflammation which aggravates disease symptoms. Recent advances in in vitro air-liquid interface 3D cultures, organoid cultures and the use of novel human and animal challenge models have evoked new understandings as to the mechanisms of viral exacerbations. In this review, we will focus on recent novel findings that elucidate how respiratory viral infections alter the epithelial barrier in the airways, the upper airway microbial environment, epigenetic modifications including miRNA modulation, and other changes in immune responses throughout the upper and lower airways. First, we reviewed the prevalence of different respiratory viral infections in causing exacerbations in chronic airway inflammatory diseases. Subsequently we also summarized how recent models have expanded our appreciation of the mechanisms of viral-induced exacerbations. Further we highlighted the importance of the virome within the airway microbiome environment and its impact on subsequent bacterial infection. This review consolidates the understanding of viral induced exacerbation in chronic airway inflammatory diseases and indicates pathways that may be targeted for more effective management of chronic inflammatory diseases.

The Microbiome and Chronic Rhinosinusitis

Chronic rhinosinusitis (CRS) is persistent inflammation and/or infection of the nasal cavity and paranasal sinuses. Recent advancements in culture-independent molecular techniques have enhanced understanding of interactions between sinus microbiota and upper airway microenvironment. The dysbiosis hypothesis-alteration of microbiota associated with perturbation of the local ecological landscape-is suggested as a mechanism involved in CRS pathogenesis. This review discusses the complex role of the microbiota in health and in CRS and considerations in sinus microbiome investigation, dysbiosis of sinus microbiota in CRS, microbial interactions in CRS, and development of preclinical models. The authors conclude with future directions for CRS-associated microbiome research.

Dual and Triple Epithelial Coculture Model Systems with Donor-Derived Microbiota and THP-1 Macrophages To Mimic Host-Microbe Interactions in the Human Sinonasal Cavities

Despite the relevance of the resident microbiota in sinonasal health and disease and the need for cross talk between immune and epithelial cells in the upper respiratory tract, these parameters have not been combined in a single in vitro model system. We have developed a coculture system of differentiated respiratory epithelium and natural nasal microbiota and incorporated an immune component. As indicated by absence of cytotoxicity and stable cytokine profiles and epithelial integrity, nasal microbiota from human origin appeared to be well tolerated by host cells, while microbial community composition remained representative for that of the human (sino)nasal cavity. Importantly, the introduction of macrophage-like cells enabled us to obtain a differential readout from the epithelial cells dependent on the donor microbial background to which the cells were exposed. We conclude that both model systems offer the means to investigate host-microbe interactions in the upper respiratory tract in a more representative way.

The epithelium of the human sinonasal cavities is colonized by a diverse microbial community, modulating epithelial development and immune priming and playing a role in respiratory disease. Here, we present a novel in vitro approach enabling a 3-day coculture of differentiated Calu-3 respiratory epithelial cells with a donor-derived bacterial community, a commensal species (Lactobacillus sakei), or a pathobiont (Staphylococcus aureus). We also assessed how the incorporation of macrophage-like cells could have a steering effect on both epithelial cells and the microbial community. Inoculation of donor-derived microbiota in our experimental setup did not pose cytotoxic stress on the epithelial cell layers, as demonstrated by unaltered cytokine and lactate dehydrogenase release compared to a sterile control. Epithelial integrity of the differentiated Calu-3 cells was maintained as well, with no differences in transepithelial electrical resistance observed between coculture with donor-derived microbiota and a sterile control. Transition of nasal microbiota from in vivo to in vitro conditions maintained phylogenetic richness, and yet a decrease in phylogenetic and phenotypic diversity was noted. Additional inclusion and coculture of THP-1-derived macrophages did not alter phylogenetic diversity, and yet donor-independent shifts toward higher Moraxella and Mycoplasma abundance were observed, while phenotypic diversity was also increased. Our results demonstrate that coculture of differentiated airway epithelial cells with a healthy donor-derived nasal community is a viable strategy to mimic host-microbe interactions in the human upper respiratory tract. Importantly, including an immune component allowed us to study host-microbe interactions in the upper respiratory tract more in depth.

IMPORTANCE Despite the relevance of the resident microbiota in sinonasal health and disease and the need for cross talk between immune and epithelial cells in the upper respiratory tract, these parameters have not been combined in a single in vitro model system. We have developed a coculture system of differentiated respiratory epithelium and natural nasal microbiota and incorporated an immune component. As indicated by absence of cytotoxicity and stable cytokine profiles and epithelial integrity, nasal microbiota from human origin appeared to be well tolerated by host cells, while microbial community composition remained representative for that of the human (sino)nasal cavity. Importantly, the introduction of macrophage-like cells enabled us to obtain a differential readout from the epithelial cells dependent on the donor microbial background to which the cells were exposed. We conclude that both model systems offer the means to investigate host-microbe interactions in the upper respiratory tract in a more representative way.

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.

An Experimental Model of Eosinophilic Chronic Rhinosinusitis Induced by Bacterial Toxins in Rabbits

Background

The pathophysiology of chronic rhinosinusitis (CRS) is still not well known due to the multifactorial etiologies involved. Bacteria play a role in the pathogenesis of CRS by various means, including biofilm adhesion, intracellular persistence, or inducing inflammation secondary to toxins. Endotoxins and exotoxins, especially Staphylococcus aureus superantigens, can produce significant immune responses in the host and are implicated in patients with CRS. The majority of animal models described for CRS revalidates the pathophysiology of acute sinusitis, ostium occlusion, or foreign body associated infection.

Objectives

To evaluate an experimental model of eosinophilic CRS using prolonged exposure to bacterial toxins. The histological changes in rabbits exposed to S. aureus enterotoxin B (SEB), lipopolysaccharide (LPS), or lipoteichoic acid (LTA) were compared.

Methods

After induction with ovalbumin (OVA) sensitization with subcutaneous injection for 2 weeks, rabbits underwent surgery to insert an indwelling catheter into the maxillary sinus. The sinus was irrigated with OVA 3 times weekly for 2 weeks, followed by sinus irrigation with bacterial toxin (SEB: 1 µg/mL, LPS: 100 ng/mL, or LTA: 100 ng/mL) 3 times weekly for 4 weeks. The histological changes in the treated sinus were compared with control rabbits.

Results

Sinuses exposed to bacterial toxins (SEB, LPS, and LTA) produced significant mucosal thickening with infiltration of inflammatory cells, notably eosinophils. SEB was the only toxin that promoted a mixed pattern of inflammation, including eosinophilic and neutrophilic infiltration.

Conclusion

Our experimental model of eosinophilic CRS in rabbits produced significant mucosal thickening and inflammation in the sinuses exposed to bacterial toxins, with histological changes analogous to what is observed in patients with CRS with nasal polyps. This model may serve as a basis for future investigation of the pathogenesis of eosinophilic CRS in relation to bacterial toxins or as a model for testing new therapeutic modalities for this disease.

Blood Loss and Visibility with Esmolol vs Labetalol in Endoscopic Sinus Surgery: A Randomized Clinical Trial

Objectives:

Improved intraoperative visibility during functional endoscopic sinus surgery (FESS) decreases the risk of serious orbital or skull base injuries. Esmolol and labetalol have been used to reduce bleeding and achieve better visibility, but it remains unclear which drug is more effective. This study aims to measure visibility scores and mucosal bleeding rates for esmolol and labetalol in FESS.

Methods:

This is a 1-year randomized double-blind trial of adults undergoing FESS at a tertiary academic center. The inclusion criteria were as follows: age 18 or older; history of chronic rhinosinusitis (CRS) with or without nasal polyps; undergoing FESS for CRS; and American Society of Anesthesiologists (ASA) physical status 1 (healthy) or 2 (patient with mild systemic disease). The exclusion criteria were as follows: pregnancy; asthma, chronic obstructive pulmonary disease (COPD), bradycardia, heart failure, end-stage renal disease, cerebrovascular accident, diabetes mellitus; preoperative use of nonsteroidal anti-inflammatory drugs (NSAIDs), aspirin, or beta-blockers; and body mass index (BMI) greater than 40 kg/m². Patients received either dose-infused esmolol or intravenous push labetalol. The primary outcome was intraoperative visibility determined by surgeon using validated scoring systems (Boezaart, Wormald). The secondary outcome was hemodynamic control (rate of blood loss, average mean arterial pressure [MAP], average heart rate [HR]). Hypothesis of no difference between drugs formed before data collection.

Results:

Of the 32 adults given drug (mean age = 50), 28 patients (13 esmolol and 15 labetalol) with complete data were included in the final analysis. There were no statistically significant differences between esmolol and labetalol in rate of blood loss (0.59 [0.28] vs 0.66 [0.37] mL/min, P = 0.62), average MAP (79.7 [7.5] vs 79.4 [7.7] mm Hg, P = .93), HR (72 [8.7] vs 68 [11.7] bpm, P = .26), or mean visibility scores for the Boezaart (3.1 [0.69] vs 3.1 [0.89], P = .85) and Wormald (6.1 [1.7] vs 5.9 [1.9], P = .72) grading scales.

Conclusions:

There were no significant differences between esmolol and labetalol in rate of blood loss, MAP control, HR, or surgical visibility in FESS. Either drug may be used, and other considerations (availability, cost) can dictate choice.

Neuroplastic changes in the olfactory bulb associated with nasal inflammation in mice

BACKGROUND

Rhinitis and rhinosinusitis are olfactory disorders caused by inflammation of the nasal passage and paranasal sinuses. Although patients with chronic rhinosinusitis have smaller olfactory bulbs (OBs), there is limited knowledge regarding the influence of chronic nasal inflammation on OB neurons.

OBJECTIVE

Repeated intranasal administration of LPS that induced persistent nasal inflammation in mice caused a loss of olfactory sensory neurons (OSNs) and gliosis and synaptic loss in the OBs within 3 weeks. The present study aimed to clarify the effects of long-term LPS treatment on the OB neurocircuit.

METHODS

LPS was repeatedly administered into a mouse nostril for up to 24 weeks. For the recovery analyses, the mice received LPS for 10 weeks and were subsequently maintained without additional treatment for another 10 weeks. The effects of these treatments on the OBs were examined histologically. Three or more mice were analyzed per group.

RESULTS

Long-term repeated LPS administration caused OB atrophy, particularly in the layers along which OSN axons travel and in the superficial external plexiform layer, in which tufted cells form synapses with interneurons. Interestingly, the OBs recovered from atrophy after cessation of LPS administration: OB volume and superficial external plexiform layer thickness returned to pretreatment levels after the nontreatment period. In contrast, OSN regeneration was incomplete.

CONCLUSION

These results suggest that chronic nasal inflammation induces structural changes in a specific OB circuit related to tufted cells, whereas tufted cells retain a high degree of plasticity that enables recovery from structural damages after inflammation subsides.

Modelling upper respiratory tract diseases: getting grips on host-microbe interactions in chronic rhinosinusitis using in vitro technologies

Chronic rhinosinusitis (CRS) is a chronic inflammation of the mucosa of the nose and paranasal sinuses affecting approximately 11% of the adult population in Europe. Inadequate immune responses, as well as a dysbiosis of the sinonasal microbiota, have been put forward as aetiological factors of the disease. However, despite the prevalence of this disease, there is no consensus on the aetiology and mechanisms of pathogenesis of CRS. Further research requires in vitro models mimicking the healthy and diseased host environment along with the sinonasal microbiota. This review aims to provide an overview of CRS model systems and proposes in vitro modelling strategies to conduct mechanistic research in an ecological framework on the sinonasal microbiota and its interactions with the host in health and CRS.

Advances in in vitro production of sheep embryos

Sheep is an important livestock in the world providing meat, milk and wool for human beings. With increasing human population, the worldwide needs of production of sheep have elevated. To meet the needs, the assistant reproductive technology including ovine in vitro embryo production (ovine IVP) is urgently required to enhance the effective production of sheep in the world. To learn the status of ovine IVP, we collected some publications related to ovine IVP through PubMed and analyzed the progress in ovine IVP made in the last five years (2012-2017). We made comparisons of these data and found that the recent advances in ovine IVP has been made slowly comparable to that of ovine IVP two decades ago. Therefore, we suggested two strategies or approaches to tackle the main problems in ovine IVP and expect that the efficiency of ovine IVP could be improved significantly when the approaches would be implemented.

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.