Challenge-induced plasma exudation and mucinous secretion in human airways

Humoral First-Line Mucosal Innate Defence in vivo

Based on observations in vivo in guinea-pig and human airways, this review presents plasma exudation as non-sieved transmission of bulk plasma across an unperturbed mucosa that maintains its normal barrier functions. Several steps have led to the present understanding of plasma exudation as a non-injurious response to mucosal challenges. The implication of a swift appearance of all circulating multipotent protein systems (also including antimicrobial peptides that now are viewed as being exclusively produced by local cells) on challenged, but intact, mucosal surfaces cannot be trivial. Yet, involvement of early plasma exudation responses in innate mucosal immunology has dwelled below the radar. Admittedly, exploration of physiological plasma exudation mechanisms requires in vivo approaches beyond mouse studies. Plasma exudation also lacks the specificity that is a hallmark of biological revelations. These aspects separate plasma exudation from mainstream progress in immunology. The whole idea, presented here, thus competes with strong paradigms currently entertained in the accepted research front. The present focus on humoral innate immunity in vivo further deviates from most discussions, which concern cell-mediated innate defence. Indeed, plasma exudation has emerged as sole in vivo source of major mucosal defence proteins that now are viewed as local cell produce. In conclusion, this review highlights opportunities for complex actions and interactions provided by non-sieved plasma proteins/peptides on the surface of intact mucosal barriers in vivo.

Broad Th2 neutralization and anti-inflammatory action of pentosan polysulfate sodium in experimental allergic rhinitis

Background

Th2 cytokines like interleukin‐4, ‐5, and ‐13 are regarded as important drivers of the immunopathology underlying allergic rhinitis (AR) and asthma. The present study explores the capacity of pentosan polysulfate sodium (PPS), a semi‐synthetic heparin‐like macromolecular carbohydrate, to bind Th2 cytokines and exert biological neutralization in vitro, as well as anti‐inflammatory actions in vivo.

Methodology

The capacity of PPS to bind recombinant Th2 cytokines was tested with surface plasmon resonance (SPR) technology and biological Th2 neutralization was assessed by Th2‐dependent proliferation assays. The in vivo anti‐inflammatory action of PPS was studied using a validated Guinea‐pig model of AR.

Results

Binding studies revealed a strong and specific binding of PPS to IL‐4, IL‐5, and IL‐13 with IC values suggesting as stronger cytokine binding than for heparin. Cytokine binding translated to a biological neutralization as PPS dose dependently inhibited Th2‐dependent cell proliferation. Topical administration of PPS 30 min prior to nasal allergen challenge of sensitized animals significantly reduced late phase plasma extravasation, luminal influx of eosinophils, neutrophils, and total lavage leukocytes. Similar, albeit not statistically secured, effects were found for tissue leukocytes and mucus hyper‐secretion. The anti‐inflammatory effects of PPS compared favorably with established topical nasal steroid treatment.

Conclusion

This study points out PPS as a potent Th2 cytokine‐binding molecule with biological neutralization capacity and broad anti‐inflammatory effects in vivo. As such PPS fulfills the role as a potential candidate molecule for the treatment of AR and further studies of clinical efficacy seems highly warranted.

Immunopathology of exercise-induced bronchoconstriction in athletes--a new modified inflammatory hypothesis

Elite athletes have a higher prevalence of exercise-induced bronchoconstriction than the general population. The pathogenesis of exercise-induced bronchoconstriction is not fully elucidated. Increasing evidence suggests that airway inflammation plays a major role in the immunopathogenesis of exercise-induced bronchoconstriction. The aim of our review is to discuss existing evidence and to present a new, modified inflammatory hypothesis of exercise-induced bronchoconstriction. Exercise alters the number and function of circulating immune cells. Episodes of upper respiratory symptoms in elite athletes do not follow the usual seasonal patterns. Moreover, they have an unusual short-term duration, which suggests a non-infectious etiology. If the pro-inflammatory response to exercise has the potential to induce symptoms that mimic respiratory tract infection, it definitely up-regulates pro-inflammatory cytokine expression in the airways. We can conclude that exercise up-regulates airway cytokine expression in a way that favors inflammation and allergic reactions in bronchi and lowers the threshold for bronchoconstriction to different stimuli like cool, dry air, allergens, and pollutants.

TRPV1 and TRPA1 stimulation induces MUC5B secretion in the human nasal airway in vivo

AIM

Nasal transient receptor potential vanilloid 1 (TRPV1) stimulation with capsaicin produces serous and mucinous secretion in the human nasal airway. The primary aim of this study was to examine topical effects of various TRP ion channel agonists on symptoms and secretion of specific mucins: mucin 5 subtype AC (MUC5AC) and B (MUC5B).

METHODS

Healthy individuals were subjected to nasal challenges with TRPV1 agonists (capsaicin, olvanil and anandamide), TRP ankyrin 1 (TRPA1) agonists (cinnamaldehyde and mustard oil) and a TRP melastatin 8 (TRPM8) agonist (menthol). Symptoms were monitored, and nasal lavages were analysed for MUC5AC and MUC5B, i.e. specific mucins associated with airway diseases. In separate groups of healthy subjects, nasal biopsies and brush samples were analysed for TRPV1 and MUC5B, using immunohistochemistry and RT-qPCR. Finally, calcium responses and ciliary beat frequency were measured on isolated ciliated epithelial cells.

RESULTS

All TRP agonists induced nasal pain or smart. Capsaicin, olvanil and mustard oil also produced rhinorrhea. Lavage fluids obtained after challenge with capsaicin and mustard oil indicated increased levels of MUC5B, whereas MUC5AC was unaffected. MUC5B and TRPV1 immunoreactivities were primarily localized to submucosal glands and peptidergic nerve fibres, respectively. Although trpv1 transcripts were detected in nasal brush samples, functional responses to capsaicin could not be induced in isolated ciliated epithelial cells.

CONCLUSION

Agonists of TRPV1 and TRPA1 induced MUC5B release in the human nasal airways in vivo. These findings may be of relevance with regard to the regulation of mucin production under physiological and pathophysiological conditions.

Gastroesophageal reflux disease and chronic sinusitis: in search of an esophageal-nasal reflex

BACKGROUND

This study was performed to explore whether or not a neural reflex linking the esophagus and the nasal airway exists, as a pathogenic mechanism accounting for the association between gastroesophageal reflux (GER) disease and chronic rhinosinusitis (CRS). A prospective trial of healthy human volunteers was performed.

METHODS

Ten healthy volunteers without GER or sinonasal disease were investigated using an acid infusion challenge test. Normal saline and hydrochloric acid were infused into the lower esophagus through an esophageal manometry catheter. Nasal responses in symptom score, nasal inspiratory peak flow, and mucus production were analyzed after the esophageal challenge.

RESULTS

A tendency for an increase in nasal mucus production was observed after esophageal stimulation with both normal saline and HCl. This returned to baseline level 45 minutes after the acid infusion. A similar trend was also observed with the measurements of nasal symptom scores and, to a lesser extent, nasal inspiratory peak flow.

CONCLUSION

These results support the possibility that a neural reflex exists between the esophagus and the paranasal sinuses via the vagus nerve. If indeed present, the reflex-mediated rhinitis derived from this neuropathic inflammation may contribute to the development of CRS in patients with GER. Further study is required to define the relationship between GER and CRS.

Wine produced by ecological methods produces relatively little nasal blockage in wine-sensitive subjects

CONCLUSION

Subjects with self-reported nasal symptoms following consumption of red wine may respond with less nasal blockage to a wine produced with ecological methods than to wine not labelled as ecologically produced.

OBJECTIVE

To compare nasal symptoms following intake of three different wines--one that was ecologically produced and two that were traditionally produced.

SUBJECTS AND METHODS

Individuals with self-reported nasal symptoms following consumption of red wine were subjected to controlled intake of three different wines in a double-blinded, randomized, and crossover design. Nasal symptoms and peak nasal inspiratory flow (PNIF) were monitored before and 15, 30, 45, and 60 min following intake of wine.

RESULTS

All wines produced nasal symptoms, notably nasal blockage. While blockage scores did not differ between the two non-ecological wines, the ecological wine was associated with significantly lower blockage scores, as compared with both the other wines.

Effects of long-term clarithromycin treatment on lavage-fluid markers of inflammation in chronic rhinosinusitis

Macrolides can be clinically effective in chronic rhinosinusitis (CRS). However, little is known about how these drugs affect pathophysiological features of CRS in vivo. In the present study, patients with CRS were subjected to long-term treatment with clarithromycin. Nasal lavages with and without histamine (40 and 400 microg ml(-1)) were carried out prior to and late into the treatment period. Histamine was included as a tool to produce plasma exudation, a process known to move free cellular products from the mucosal tissue into the airway lumen thereby enriching nasal surface liquids with such products. Interleukin-8 (IL-8), myeloperoxidase (MPO), eosinophil cationic protein (ECP), alpha(2)-macroglobulin and fucose were monitored as indices of pro-inflammatory cytokine production, neutrophil and eosinophil granulocyte activities, plasma exudation and mucinous secretion, respectively. Clarithromycin reduced the lavage fluid levels of IL-8 at the low-dose histamine observation (P<0.001). There was a trend towards reduced MPO by the treatment, whereas ECP was significantly reduced at the low-dose histamine observation (P<0.05). alpha(2)-Macroglobulin was reduced by clarithromycin (saline lavages) (P = 0.05), whereas fucose was unaffected. The exudative responsiveness to high-dose histamine was significantly reduced by the treatment (P<0.05). Furthermore, significantly lower levels of fucose were observed at the low-dose histamine observation (P<0.01). We conclude that long-term clarithromycin treatment likely exerts an anti-inflammatory effect in CRS.

Airway injury as a mechanism for exercise-induced bronchoconstriction in elite athletes

Exercise-induced bronchoconstriction (EIB) is a consequence of evaporative water loss in conditioning the inspired air. The water loss causes cooling and dehydration of the airway surface. One acute effect of dehydration is the release of mediators, such as prostaglandins, leukotrienes, and histamine, that can stimulate smooth muscle, causing contraction and a change in vascular permeability. Inspiring cold air increases dehydration of the surface area and causes changes in bronchial blood flow. This article proposes that the pathogenesis of EIB in elite athletes relates to the epithelial injury arising from breathing poorly conditioned air at high flows for long periods of time or high volumes of irritant particles or gases. The evidence to support this proposal comes from many markers of injury. The restorative process after injury involves plasma exudation and movement of cells into the airways, a process repeated many times during a season of training. This process has the potential to expose smooth muscle to a wide variety of plasma- and cell-derived substances. The exposure to these substances over time can lead to an alteration in the contractile properties of the smooth muscle, making it more sensitive to mediators of bronchoconstriction. It is proposed that cold-weather athletes have airway hyperresponsiveness (AHR) to pharmacologic agents as a result of epithelial injury. In those who are allergic, AHR can also be expressed as EIB. The role of beta(2)-receptor agonists in inhibiting and enhancing the development of AHR and EIB is discussed.

How does exercise cause asthma attacks?

PURPOSE OF REVIEW

To remind readers that evaporative water loss from the airway surface is the stimulus for exercise-induced bronchoconstriction. To emphasize that recruitment of the peripheral airways determines severity of exercise-induced bronchoconstriction. To draw attention to the potential for injury of the epithelium and for plasma exudation to contribute to the pathogenesis of exercise-induced bronchoconstriction in athletes. To emphasize that many inflammatory mediators are involved in exercise-induced bronchoconstriction and that some are found in both asthmatic and healthy subjects.

RECENT FINDINGS

That inflammatory mediators are released into the airways in response to exercise and can be measured by inducing sputum (histamine, cysteinyl leukotrienes) or collecting condensate from exhaled air (cysteinyl leukotrienes and adenosine). The concentration of mediators was reduced in response to a combination of loratadine and montelukast. Exercise is a stimulus for upregulating the genes coding for the 5-lipoxygenase pathway in healthy subjects.

SUMMARY

Dehydration of the airways results in release of mediators. The likely source of these mediators is the mast cell. Epithelial injury occurs in exercise-induced bronchoconstriction. The process of repair may contribute to the development of airway hyperresponsiveness in healthy subjects. Measuring the airway response to exercise, or a surrogate for exercise, as an indicator of airway hyperresponsiveness is warranted in patients with symptoms of asthma.

A double-blind, randomized, placebo-controlled trial of macrolide in the treatment of chronic rhinosinusitis

OBJECTIVES

The antiinflammatory effect of macrolide antibiotics has been well-established, as has their role in the treatment of certain disorders of chronic airway inflammation. Several studies have suggested that long-term, low-dose macrolides may be efficacious in the treatment of chronic rhinosinusitis; however, these studies have lacked a control group. To date, this effect has not been tested in a randomized, placebo-controlled study.

METHOD

The authors conducted a double-blind, randomized, placebo-controlled clinical trial on 64 patients with chronic rhinosinusitis. Subjects received either 150 mg roxithromycin daily for 3 months or placebo. Outcome measures included the Sinonasal Outcome Test-20 (SNOT-20), measurements of peak nasal inspiratory flow, saccharine transit time, olfactory function, nasal endoscopic scoring, and nasal lavage assays for interleukin-8, fucose, and a2-macroglobulin.

RESULTS

There were statistically significant improvements in SNOT-20 score, nasal endoscopy, saccharine transit time, and IL-8 levels in lavage fluid (P<.05) in the macrolide group. A correlation was noted between improved outcome measures and low IgE levels. No significant improvements were noted for olfactory function, peak nasal inspiratory flow, or lavage levels for fucose and a2-macroglobulin. No improvement in any outcome was noted in the placebo-treated patients.

CONCLUSION

These findings suggest that macrolides may have a beneficial role in the treatment of chronic rhinosinusitis, particularly in patients with low levels of IgE, and supports the in vitro evidence of their antiinflammatory activity. Additional studies are required to assess their place in clinical practice.