Upper airway defence mechanisms

Fokkens, W. J.; Scheeren, R. A.

doi:10.1053/prrv.2000.0073

Cited by 40 publications

(43 citation statements)

References 13 publications

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“…The upper airway is continuously exposed to micro‐organisms and other foreign substances, like allergens. These are normally eliminated by the first layer of defence in the mucosa, consisting of mucus, ciliated epithelial cells and secretion of different molecules, such as lysozymes [8]. The recent finding of Toll‐like receptors (TLRs) on epithelial cells has indicated a role for the nasal mucosa also in the primary immune response [9].…”

Section: Introductionmentioning

confidence: 99%

Lipopolysaccharide administration to the allergic nose contributes to lower airway inflammation

Bachar

Gustafsson

Jansson

et al. 2007

Clin Experimental Allergy

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Background Allergic rhinitis is an inflammatory reaction not confined to a single local compartment, but rather involving the whole airway system. Allergens known to induce allergic rhinitis are not always the sole trigger of the inflammatory reaction. Infections and organic dust might also cause exacerbations of rhinitis and associated conditions.Objective To examine the effects of intranasal LPS exposure, as a surrogate for upper airway bacterial infections, in patients with symptomatic allergic rhinitis.Methods 14 patients with a history of moderate to severe pollen induced allergic rhinitis were challenged intranasally with LPS. After 3 to 6 weeks the same patients were challenged again, first with allergen and 24 hours later with LPS. Nasal symptom scores, nasal lavage leukocyte counts and nasal airway resistance were assessed at 6 and 24 h after each provocation along with measurements of nitric oxide (NO) levels in nose and lung.Results Six hours after the LPS challenge, increased level of leucocytes could be obtained in the lavage fluid, but no symptoms were experienced and no increase in nasal resistance could be recorded. The NO production in the upper and lower airways was similar before and 6 h after the provocation. In contrast, in patients exposed to pollen prior to the LPS challenge, both the nasal and the pulmonary NO levels were enhanced. This was accompanied by an increase in leukocytes. ConclusionThe present study demonstrates a priming effect of allergen on the nasal response to LPS as well as the presence of a systemic link between airway mucosal sites in upper and lower airways. This suggests that exogenously derived signals, like upper airway infections, can interfere with the initiation, maintenance and progression of asthma.Abs word count: 279 (max 300) 3

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Section: Introductionmentioning

confidence: 99%

Lipopolysaccharide administration to the allergic nose contributes to lower airway inflammation

Bachar

Gustafsson

Jansson

et al. 2007

Clin Experimental Allergy

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“…In the case of chemical agents, this is achieved by the capture and neutralization of foreign agents in the inspired airstream, limiting their impact on lower airway structures [15]. It has also been demonstrated that the nose can serve as a repository for inhaled viral and bacterial pathogens where they can be eliminated or held in check by immune defenses, thereby reducing the risk and/or severity of lower airway infections [16-19].…”

Section: Introductionmentioning

confidence: 99%

“…Evidence indicates that inherent antioxidant and other protective defenses in the tissues of the upper and lower respiratory structures mitigate pulmonary inflammation and that enhancement of these protective pathways can reduce tissue damage, immune responses and morbidity [20,21]. However, little is known about mechanisms through which nasal antioxidant processes might be augmented and, if so, to what extent such augmentation would be effective as an intervention.…”

Section: Introductionmentioning

confidence: 99%

Antioxidant components of naturally-occurring oils exhibit marked anti-inflammatory activity in epithelial cells of the human upper respiratory system

et al. 2011

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BackgroundThe upper respiratory tract functions to protect lower respiratory structures from chemical and biological agents in inspired air. Cellular oxidative stress leading to acute and chronic inflammation contributes to the resultant pathology in many of these exposures and is typical of allergic disease, chronic sinusitis, pollutant exposure, and bacterial and viral infections. Little is known about the effective means by which topical treatment of the nose can strengthen its antioxidant and anti-inflammatory defenses. The present study was undertaken to determine if naturally-occurring plant oils with reported antioxidant activity can provide mechanisms through which upper respiratory protection might occur.MethodsControlled exposure of the upper respiratory system to ozone and nasal biopsy were carried out in healthy human subjects to assess mitigation of the ozone-induced inflammatory response and to assess gene expression in the nasal mucosa induced by a mixture of five naturally-occurring antioxidant oils - aloe, coconut, orange, peppermint and vitamin E. Cells of the BEAS-2B and NCI-H23 epithelial cell lines were used to investigate the source and potential intracellular mechanisms of action responsible for oil-induced anti-inflammatory activity.ResultsAerosolized pretreatment with the mixed oil preparation significantly attenuated ozone-induced nasal inflammation. Although most oil components may reduce oxidant stress by undergoing reduction, orange oil was demonstrated to have the ability to induce long-lasting gene expression of several antioxidant enzymes linked to Nrf2, including HO-1, NQO1, GCLm and GCLc, and to mitigate the pro-inflammatory signaling of endotoxin in cell culture systems. Nrf2 activation was demonstrated. Treatment with the aerosolized oil preparation increased baseline levels of nasal mucosal HO-1 expression in 9 of 12 subjects.ConclusionsThese data indicate that selected oil-based antioxidant preparations can effectively reduce inflammation associated with oxidant stress-related challenge to the nasal mucosa. The potential for some oils to activate intracellular antioxidant pathways may provide a powerful mechanism through which effective and persistent cytoprotection against airborne environmental exposures can be provided in the upper respiratory mucosa.

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“…They let air pass to the pharynx and protect the tracheobronchial tree by means of humidification, warming, and filtration of the air (Fokkens and Scheeren, 2000), antioxidants present in the mucous epiphase (Koren et al, 1990), and reflexes such as sneezing. This passage represents between 30 and 50% of the total resistance of inspired air in humans (Geurkink, 1983;Hilger and Hilger, 1987).…”

Section: Introductionmentioning

confidence: 99%

Histological changes in rat nasal epithelia after unilateral neonatal naris occlusion

Cámara

Garrosa

Gayoso

2006

Microscopy Res & Technique

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The authors studied the extent of the different epithelia lining the nasal fossae of the albino rat after neonatal closure of one naris. Newborn pups were anesthetized by hypothermia and the external opening of their right naris cauterized, while littermates served as controls. Animals were sacrificed at 3 months, and the occluded (OCF) and nonoccluded (NOF) fossae of experimental animals as well as both fossae of control animals (CTF) were histologically studied. In both control and experimental animals, nasal fossae were lined by five different types of epithelia: squamous stratified, transitional, metaplastic, respiratory, and olfactory epithelia. It was found that closure of one naris provokes reorganization of the epithelial lining in both the occluded and nonoccluded side. In CTF airflow, physical conditions as well as pollutants and biological agents irritate the epithelial lining, causing squamous metaplasia as well as metaplastic epithelium showing inflammation in rostral levels. In CTF caudal levels, the metaplastic epithelium appears to a lesser degree and the respiratory epithelium prevails, except for the most caudal level where the olfactory epithelium is prevalent. In OCF, the protected environment created prevents the occurrence of metaplastic epithelium, the transitional, respiratory, and olfactory epithelia developing in the corresponding area instead. In NOF, where the airflow is double, the same pattern occurs as in CTF, although metaplastic epithelium values are approximately double, suggesting a clear linear effect. An outstanding feature observed was the increased extent of the olfactory epithelium in OCF regarding NOF, although changes in its morphological structure were not found. Airflow properties, including pressure, coldness, velocity, and turbulence, as well as biological and chemical hazards present in inflow, cause histological reorganization of the nasal epithelium lining during postnatal development. Results prove the need to consider airflow changes in nasal fossae surgery and point to the protective value of naris closure in ENT clinics, supporting it as a treatment of atrophic rhinitis.

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Upper airway defence mechanisms

Cited by 40 publications

References 13 publications

Lipopolysaccharide administration to the allergic nose contributes to lower airway inflammation

Lipopolysaccharide administration to the allergic nose contributes to lower airway inflammation

Antioxidant components of naturally-occurring oils exhibit marked anti-inflammatory activity in epithelial cells of the human upper respiratory system

Histological changes in rat nasal epithelia after unilateral neonatal naris occlusion

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