[Guidelines of the German Respiratory Society for Diagnosis and Treatment of Adults Suffering from Acute, Subacute and Chronic Cough]

The present 2019 S2k consensus guideline of the German Respiratory Society was written - in contrast to the predecessor more general S3 guidelines from 2004 and 2010 - for pneumologists, since 2014 the German College of General Practitioners and Family Physicians (DEGAM) published his own cough guidelines.The guideline contains 48 recommendations agreed by consensus and 16 statements, which are explained in the background text in the following nine chapters: epidemiology, physiology, classification, acute, subacute or chronic cough, diagnostics and therapy; an extra chapter was dedicated to chronic idiopathic cough. Further emphasis of the guideline is the physiology of cough in anticipation of the introduction of new drugs, as well as detailed treatises on cough triggered by affections in the upper respiratory tract or by gastroesophageal reflux. The guideline should provide the pneumologist with the latest knowledge from neighboring disciplines required for diagnosis and therapy of cough. The clinical chapters also contain a short summary, practical recommendations and a bibliography of their own. Three new, simplified algorithms for acute, subacute and chronic cough round off the Diagnostics chapter.

High probability of comorbidities in bronchial asthma in Germany

Clinical experience has shown that allergic and non-allergic respiratory, metabolic, mental, and cardiovascular disorders sometimes coexist with bronchial asthma. However, no study has been carried out that calculates the chance of manifestation of these disorders with bronchial asthma in Saarland and Rhineland-Palatinate, Germany. Using ICD10 diagnoses from health care institutions, the present study systematically analyzed the co-prevalence and odds ratios of comorbidities in the asthma population in Germany. The odds ratios were adjusted for age and sex for all comorbidities for patients with asthma vs. without asthma. Bronchial asthma was strongly associated with allergic and with a lesser extent to non-allergic comorbidities: OR 7.02 (95%CI:6.83-7.22) for allergic rhinitis; OR 4.98 (95%CI:4.67-5.32) allergic conjunctivitis; OR 2.41 (95%CI:2.33-2.52) atopic dermatitis; OR 2.47 (95%CI:2.16-2.82) food allergy, and OR 1.69 (95%CI:1.61-1.78) drug allergy. Interestingly, increased ORs were found for respiratory diseases: 2.06 (95%CI:1.64-2.58) vocal dysfunction; 1.83 (95%CI:1.74-1.92) pneumonia; 1.78 (95%CI:1.73-1.84) sinusitis; 1.71 (95%CI:1.65-1.78) rhinopharyngitis; 2.55 (95%CI:2.03-3.19) obstructive sleep apnea; 1.42 (95%CI:1.25-1.61) pulmonary embolism, and 3.75 (95%CI:1.64-8.53) bronchopulmonary aspergillosis. Asthmatics also suffer from psychiatric, metabolic, cardiac or other comorbidities. Myocardial infarction (OR 0.86, 95%CI:0.79-0.94) did not coexist with asthma. Based on the calculated chances of manifestation for these comorbidities, especially allergic and respiratory, to a lesser extent also metabolic, cardiovascular, and mental disorders should be taken into consideration in the diagnostic and treatment strategy of bronchial asthma.

BRONCHIAL ASTHMA

PREVALENCE OF CO-EXISTING DISEASES IN GERMANY: Patients in Germany with bronchial asthma are highly likely to suffer from co-existing diseases and their treatments should reflect this. Quoc Thai Dinh at Saarland University Hospital in Homburg, Germany, and co-workers conducted a large-scale study of patients presenting with bronchial asthma in the Saarland region between 2009 and 2012. Patients with asthma made up 5.4% of the region's total population, with a higher prevalence occurring in females. They found that bronchial asthma was strongly associated with allergic comorbidities such as rhinitis. Indeed, asthmatic patients had a seven times higher chance to suffer from allergic rhinitis than the rest of the population, and were at higher risk of respiratory diseases like pneumonia and obstructive sleep apnea syndrome. Further associations included cardiovascular, metabolic and mental disorders. Dinh's team call for asthma treatments to take such comorbidities into account.

Local Effects on Airway Inflammation and Systemic Uptake of 5 nm PEGylated and Citrated Gold Nanoparticles in Asthmatic Mice

Nanotechnology is showing promise in many medical applications such as drug delivery and hyperthermia. Nanoparticles administered to the respiratory tract cause local reactions and cross the blood-air barrier, thereby providing a means for easy systemic administration but also a potential source of toxicity. Little is known about how these effects are influenced by preexisting airway diseases such as asthma. Here, BALB/c mice are treated according to the ovalbumin (OVA) asthma protocol to promote allergic airway inflammation. Dispersions of polyethylene-glycol-coated (PEGylated) and citrate/tannic-acid-coated (citrated) 5 nm gold nanoparticles are applied intranasally to asthma and control groups, and (i) airway resistance and (ii) local tissue effects are measured as primary endpoints. Further, nanoparticle uptake into extrapulmonary organs is quantified by inductively coupled plasma mass spectrometry. The asthmatic precondition increases nanoparticle uptake. Moreover, systemic uptake is higher for PEGylated gold nanoparticles compared to citrated nanoparticles. Nanoparticles inhibit both inflammatory infiltrates and airway hyperreactivity, especially citrated gold nanoparticles. Although the antiinflammatory effects of gold nanoparticles might be of therapeutic benefit, systemic uptake and consequent adverse effects must be considered when designing and testing nanoparticle-based asthma therapies.

Transcriptional down-regulation of suppressor of cytokine signaling (SOCS)-3 in chronic obstructive pulmonary disease

BACKGROUND

Tobacco is a leading environmental factor in the initiation of respiratory diseases and causes chronic obstructive pulmonary disease (COPD). Suppressor of cytokine signaling (SOCS) family members are involved in the pathogenesis of many inflammatory diseases and SOCS-3 has been shown to play an important role in the regulation, onset and maintenance of airway allergic inflammation indicating that SOCS-3 displays a potential therapeutic target for anti-inflammatory respiratory drugs development. Since chronic obstructive pulmonary disease (COPD) is also characterized by inflammatory changes and airflow limitation, the present study assessed the transcriptional expression of SOCS-3 in COPD.

METHODS

Real-time PCR was performed to assess quantitative changes in bronchial biopsies of COPD patients in comparison to unaffected controls.

RESULTS

SOCS-3 was significantly down-regulated in COPD at the transcriptional level while SOCS-4 and SOCS-5 displayed no change.

CONCLUSIONS

It can be concluded that the presently observed inhibition of SOCS-3 mRNA expression may be related to the dysbalance of cytokine signaling observed in COPD.

[Innervation of the airways in asthma bronchiale and chronic obstructive pulmonary disease (COPD)]

Airway nerves have the capacity to control airway functions via neuronal reflexes and through neuromediators and neuropeptides. Neuronal mechanisms are known to play a key role in the initiation and modulation of airway hyperresponsiveness and inflammation. Therefore, the nerve fibres may contribute to airway narrowing in asthma and COPD. In addition to the traditional transmitters such as norepinephrine in postganglionic sympathetic nerve fibres and acetylcholine in parasympathetic nerve fibres, a large number of neuropeptides have been identified to have different pharmacological effects on the muscle tone of the vessels and bronchi, mucus secretion and immune cells. Meanwhile, a broad range of stimuli including capsaicin, bradykinin, hyperosmolar saline, tobacco smoke, allergens, ozone, inflammatory mediators and even cold, dry air have been shown to activate sensory nerve fibres to release neuropeptides such as the tachykinins substance P (SP) and neurokinin A (NKA) to mediate neurogenic inflammation. Different aspects of the neurogenic inflammation have been well studied in animal models of chronic airway inflammation and anticholinergic agents such as ipratropium bromide (Atrovent (®)) and tiotropium bromide (Spiriva (®)) have been proved to be important when used as bronchodilators for the treatment of obstructive airway diseases such as COPD. However, little is known about the role of neurogenic airway inflammation in human diseases. In this review, we address the current knowledge of the airway sensory nerves in human asthma and COPD.

Catheter fragmentation and local lysis in two lung transplant patients with pulmonary embolism

In conjunction with the rising number of lung transplant operations in the past decade, an increased predisposition to venous thrombosis (VT), particularly within the first year posttransplantation has been observed. Previous studies have revealed that between 8.6% and 12% of patients develop VT, which can ultimately result in pulmonary emboli (PE).Transplanted lungs pose a much greater infarction risk due to their lack of collateral vascularisation, relying entirely on the vasa publica--the pulmonary artery--in the absence of vasa privata. Such losses in viable lung parenchyma are always serious, but carry still greater risks for single-lung transplant recipients, an early diagnosis and treatment remain critical. Here we report on two cases of PE after lung transplantation, both of whom were managed with catheter fragmentation and local thrombolysis. In our opinion, this approach represents a viable treatment for symptomatic PE in lung transplant recipients. The benefits and risks of the alternative treatment options in these special cases will be reviewed and the definitive therapy was described. In the patients treated, catheter fragmentation with localized thrombolysis resulted in short term improvements in graft function, but could not prevent later lung infarction in one case.

Mobile Air Quality Studies (MAQS)-an international project

Due to an increasing awareness of the potential hazardousness of air pollutants, new laws, rules and guidelines have recently been implemented globally. In this respect, numerous studies have addressed traffic-related exposure to particulate matter using stationary technology so far. By contrast, only few studies used the advanced technology of mobile exposure analysis. The Mobile Air Quality Study (MAQS) addresses the issue of air pollutant exposure by combining advanced high-granularity spatial-temporal analysis with vehicle-mounted, person-mounted and roadside sensors. The MAQS-platform will be used by international collaborators in order 1) to assess air pollutant exposure in relation to road structure, 2) to assess air pollutant exposure in relation to traffic density, 3) to assess air pollutant exposure in relation to weather conditions, 4) to compare exposure within vehicles between front and back seat (children) positions, and 5) to evaluate "traffic zone"-exposure in relation to non-"traffic zone"-exposure.Primarily, the MAQS-platform will focus on particulate matter. With the establishment of advanced mobile analysis tools, it is planed to extend the analysis to other pollutants including NO2, SO2, nanoparticles and ozone.

Dopamine D2 receptor mRNA expression is increased in the jugular-nodose ganglia of rats with nitrogen dioxide-induced chronic bronchitis

The bronchodilatatory effect of inhaled dopamine or dopamine D(2) receptor agonists in cases of bronchial constriction may involve the suppression of pathologically increased airway sensory nerve activity. The aim of this study is to investigate the regulation of the dopamine D(2) receptor mRNA expression in the ganglia of rats with nitrogen dioxide-induced chronic bronchitis compared with that in ganglia of healthy control animals. Rats were exposed to nitrogen dioxide (10 ppm, 20 d) and dopamine D(2) receptor mRNA levels in sensory ganglia (jugular-nodose, trigeminal, cervical dorsal root and thoracic dorsal root ganglia) were examined by quantitative real-time polymerase chain reaction and compared to control tissues. Whereas for trigeminal and dorsal root ganglia the dopamine D(2) receptor expression levels showed no difference between both animal groups, there was a significant (p<0.05) increase in the jugular-nodose ganglia with a 2.1-fold factor. The increase of dopamine D(2) receptor mRNA in jugular-nodose sensory neurons which innervate the airways may represent a neurochemical basis for the effects seen in man and animal models following topical administration of dopamine or dopamine agonists onto the respiratory epithelium.

Inter-disease comparison of research quantity and quality: bronchial asthma and chronic obstructive pulmonary disease

BACKGROUND

The two obstructive airway diseases bronchial asthma and chronic obstructive pulmonary disease (COPD) represent major global causes of disability and death. Whereas COPD research was largely underfunded in the 1980s and 1990s, increased funding activities have been initiated since the year 2000. However, detailed scientometric data on the development of research for asthma and COPD have not been generated so far.

METHODS

The present scientometric study was conducted to establish a database of research quantity and quality in the 20-year period between 1987 and 2006 using the Web of Science information system and the United Kingdom and Germany for comparison of research activities.

RESULTS

The information database Web of Science was screened and during the period from 1987 to 2006 a number of 8,874 items related to asthma was published by UK affiliations. Of these, 1,824 were published in cooperation with a total of 86 other countries. This is a ratio of 20.55%. In the same period, 3,341 items were published by German institutions (923 in cooperation with 56 other countries, ratio of 27.63%). Citation analysis demonstrated an average citation of 24.48 per UK article and 17.62 per German article. For COPD, 2,179 items were published by UK affiliations and 689 items by German institutions. Of the UK COPD publications, 570 were published in cooperations with 47 countries (ratio of 22.95 %). By contrast, 218 of the 689 German COPD articles were published with 29 other countries (ratio of 25.49%). When citation analysis was performed, average citation ratios of 18.93 for the UK and 10.61 for German were found.

CONCLUSION

Summarizing this first country-specific comparative benchmarking analysis for obstructive pulmonary diseases it can be concluded that (1) asthma research dominated in the past 20 years; (2) COPD research gained importance in the field since the end of the 1990s; (3) there are large differences present in the research output between the two high-income countries examined.

Cough as a symptom and a disease entity: scientometric analysis and density-equalizing calculations

BACKGROUND

Cough is a prominent symptom of many allergic diseases and a major health burden but there is little information available on the current state of research in this area.

OBJECTIVES

To analyze long-term developments in cough research and recent trends.

METHODS

We searched the Thomson Reuters Web of Science databases for cough-related items published between 1900 and 2007 and analyzed the results using scientometric methods and density-equalizing calculations.

RESULTS

We found 12 960 cough-related publications from 132 countries for the period studied. The most productive country was the United States of America (USA), followed by the United Kingdom (UK), France, Japan, Canada, and Germany. These 12 960 published items were cited 165 868 times. The average number of citations per item increased from 1976 to 1992, with peaks in 1977, 1979, 1981, 1984, 1989 and 1992. Each of these years was followed by a decrease in citation numbers. Bilateral and multilateral cooperation analysis using the radar chart technique showed a progressive increase in international co-authorship starting at the beginning of the 1990s, with a leading role by the USA and the UK.

CONCLUSION

We detected a marked increased in cough-related research starting in the 1990s. While the majority of data originates from the US, other countries have taken a leading position in terms of research quality (number of citations per item).

Desacyl ghrelin inhibits the orexigenic effect of peripherally injected ghrelin in rats

Studies showed that the metabolic unlike the neuroendocrine effects of ghrelin could be abrogated by co-administered unacylated ghrelin. The aim was to investigate the interaction between ghrelin and desacyl ghrelin administered intraperitoneally on food intake and neuronal activity (c-Fos) in the arcuate nucleus in non-fasted rats. Ghrelin (13 microg/kg) significantly increased food intake within the first 30 min post-injection. Desacyl ghrelin at 64 and 127 microg/kg injected simultaneously with ghrelin abolished the stimulatory effect of ghrelin on food intake. Desacyl ghrelin alone at both doses did not alter food intake. Both doses of desacyl ghrelin injected separately in the light phase had no effects on food intake when rats were fasted for 12h. Ghrelin and desacyl ghrelin (64 microg/kg) injected alone increased the number of Fos positive neurons in the arcuate nucleus compared to vehicle. The effect on neuronal activity induced by ghrelin was significantly reduced when injected simultaneously with desacyl ghrelin. Double labeling revealed that nesfatin-1 immunoreactive neurons in the arcuate nucleus are activated by simultaneous injection of ghrelin and desacyl ghrelin. These results suggest that desacyl ghrelin suppresses ghrelin-induced food intake by curbing ghrelin-induced increased neuronal activity in the arcuate nucleus and recruiting nesfatin-1 immunopositive neurons.

Trigeminal nasal-specific neurons respond to nerve growth factor with substance-P biosynthesis

BACKGROUND

Nerve growth factor (NGF) has been found to induce substance-P biosynthesis in large-diameter A-fibres vagal airway neurons. However, the effect of NGF on trigeminal neurons innervating the nasal mucosa of the mouse has not been investigated so far.

OBJECTIVE

NGF has been implicated in allergic diseases by modulating sensory nerves. Therefore, the present study investigated the effect of NGF on neuropeptides expression such as substance-P and glutamate in nasal trigeminal neurons.

METHODS

Using neuronal tracing in combination with double labelling immunohistochemistry the expression of substance-P, glutamate and neurofilament protein 68-kDa expression was examined in nasal-specific trigeminal neurons of BALB/c-mice.

RESULTS

The numbers of Fast blue-labelled trigeminal neurons expressing substance-P were significantly increased after NGF exposure (NGF-treated ganglia: 16.4 +/- 0.6% vs. control: 7.0 +/- 0.4%, P<or=0.001). NGF treatment-induced substance-P biosynthesis in neurofilament-positive (NGF-treated ganglia: 8.6 +/- 0.2% vs. control: 1.1 +/- 0.2%, P<or=0.001) as well as neurofilament-negative (NGF-treated ganglia: 7.8 +/- 0.6% vs. control: 5.9 +/- 0.4%, P=0.05) and non-glutamatergic neurons (NGF-treated ganglia: 11.8 +/- 1.9% vs. control 1.1 +/- 1.0%, P<or=0.001) 24 h after NGF exposure.

CONCLUSION

Under normal conditions, substance-P was expressed in nasal-specific neurofilament-negative, glutamatergic and C-fibre neurons. Nasal-specific trigeminal neurons respond to NGF treatment with substance-P biosynthesis in non-glutamatergic, neurofilament-positive as well as -negative neurons. These findings suggest that nasal-specific trigeminal neurons are composed of heterogenous subpopulations in relation to their peptide profiles and therefore may have different functions in neurogenic airway inflammation.

IL-8 production and AP-1 transactivation induced by UVA in human keratinocytes: roles of D-alpha-tocopherol

Identification of individual response-signal pathway induced by UVA-irradiation is necessary for understanding photo-biological and -pathological mechanisms with respect to the prevention of UV-irradiated skin damage and aging. Here, we investigated the role of D-alpha-tocopherol in the regulation of IL-8 production and AP-1 binding activity in UVA-irradiated human keratinocytes. UVA dramatically upregulated IL-8 mRNA expression and protein secretion and enhanced the AP-1-DNA binding activity. These effects of UVA irradiation were effectively reduced by D-alpha-tocopherol in a dose-dependent manner. The human keratinocytes expressed various NAD(P)H oxidase components, gp91phox homologues Nox1, and p22phox, p47phox, p67phox, as well as NOXO1, suggesting that cellular stress induced by UVA included the activation of non-phagocytic NADPH oxidase system, leading to AP-1 transactivation and IL-8 expression. D-alpha-tocopherol significantly inhibited the NADPH oxidase activity and the formation of malondialdehyde-thiobarbituric acid under UVA exposure. These results demonstrated that D-alpha-tocopherol may be able to prevent the IL-8 upregulation and the increase in AP-1 activation induced by UVA irradiation through down-modulating cellular oxidative stress.

Dose-dependent inhibition of allergic inflammation and bronchial hyperresponsiveness by budesonide in ovalbumin-sensitised Brown-Norway rats

Corticosteroids are known to inhibit bronchial hyperresponsiveness (BHR) and allergic inflammation but there is little information on its dose-dependence. We examined the effect of different doses of the glucocorticosteroid budesonide in an allergic model. Brown-Norway rats were sensitised to ovalbumin (OVA) and pretreated with an intra-gastric dose of budesonide (0.1, 1.0, or 10 mgkg(-1)). Exposure to OVA induced BHR, accumulation of eosinophils in the bronchoalveolar lavage (BAL) fluid and in the airways submucosa. Budesonide dose-dependently inhibited BAL fluid influx of lymphocytes, eosinophils and neutrophils, tissue eosinophils and lymphocytes and BHR. At 0.1 mgkg(-1), budesonide did not inhibit these parameters but at 1 mgkg(-1), BAL fluid eosinophils and T-cells, and submucosal T-cells were significantly reduced. At 10 mgkg(-1), budesonide suppressed BHR, BAL fluid inflammatory cells numbers and tissue eosinophilia. T-cell numbers were more related to BHR than eosinophil numbers. Budesonide inhibited both airway inflammation and BHR, but BAL fluid eosinophil cell counts may be dissociated from BHR.

Inhibition of citric acid- and capsaicin-induced cough by novel TRPV-1 antagonist, V112220, in guinea-pig

BACKGROUND

Cough reflex can be induced by the pepper extract capsaicin and by low pH in guinea-pig airways. Transient receptor potential vanniloid-1 (TPRV-1) is expressed in the sensory and afferent nerve fibres in airways.

OBJECTIVE

We hypothesized that a novel pyridazinylpiperazine analog TPRV-1 inhibitor can effectively reduce cough reflex stimulated by citric acid and capsaicin.

METHODS

Guinea pigs were injected with specific TPRV-1 inhibitor, V112220, a pyridazinylpiperazine analog of N-(4-tertiarybutylphenyl)-4-(3-chloropyridin-2-yl) tetrahydropyrazine-1(2H)-carbox-amide (BCTC) (3 mg/kg) intra-peritoneally. One hour before cough response assessment. Coughs were recorded using a recorder system that identified cough sound and accompanying expiratory flows, distinct from sneezes. Guinea-pigs exposed to citric acid (0.4 M) and to capsaicin (10-4M) aerosols, in succession separately by 2 hours.

RESULTS

V112220 significantly inhibited the number of coughs induced by citric acid (73 +/- 11%, p < 0.01) and capsaicin (70 +/- 9.4%, p < 0.05) compared to vehicle control.

CONCLUSION

A novel pyridazinylpiperazine analog TPRV-1 inhibitor can inhibit the cough reflex, induced by both low pH and capsaicin, suggesting that it could be clinically beneficial in treatment of cough.

Selective induction of nerve growth factor and brain-derived neurotrophic factor by LPS and allergen in dendritic cells

BACKGROUND

Neurotrophins are produced by various cells upon different stimuli and participate in the initiation and regulation of inflammation in various diseases including allergy and asthma, but little is known about the production and control of neurotrophins by dendritic cells (DCs). The aim of this study was to assess whether DCs produce the neurotrophins nerve growth factor (NGF) and brain-derived neurotrophic factor (BDNF), and whether inflammatory stimuli or allergens are able to induce the production of neurotrophic factors.

METHODS

Monocyte-derived dendritic cells (MoDCs) were generated from different donors. The neurotrophins NGF and BDNF were demonstrated by RT-PCR, Western blotting, flow cytometry analysis and fluorescence microscopy. MoDCs were cultured and stimulated with lipopolysaccharide (LPS) or allergen for 24 h. The supernatants and cells were collected. Measurement for NGF and BDNF was performed by ELISA.

RESULTS

DCs express mRNA for the neurotrophins NGF and BDNF. Proteins were detectable by Western blot, FACS analysis and fluorescence microscopy. LPS led to an up-regulation of BDNF, while NGF was unaffected. Cell lysates demonstrated an increased amount of BDNF after stimulation with LPS or allergen, while NGF was not affected significantly.

CONCLUSIONS

DCs are a source of neurotrophins. LPS selectively regulates the production of BDNF. Allergen stimulation leads to an LPS-independent regulation. This contributes to a complex involvement of neurotrophins in allergic diseases.

Cell type-specific regulation of brain-derived neurotrophic factor in states of allergic inflammation

BACKGROUND

Brain-derived neurotrophic factor (BDNF) is a molecule influencing neuronal proliferation and differentiation. In states of allergy, it may orchestrate inflammatory changes by linking the immune system with the nervous system. Because the precise regulation of gene transcription in mast cells MCs is not clear, the present studies assessed the gene regulation of BDNF in this inflammatory cell type.

METHODS

Transcriptional expression of BDNF in human skin was studied in isolated cells using RT-PCR. In situ lesional MC BDNF protein expression was analysed by immunohistochemistry and related to the differential staining of MCs and functional effects of BDNF on HaCaT keratinocytes.

RESULTS

BDNF mRNA expression was found in isolated human skin MCs, keratinocytes, and fibroblasts. Also, low levels were found in endothelial cells and melanocytes. BDNF protein expression was found in situ in lesional and non-lesional MCs. A significantly decreased expression of BDNF protein was found in atopic dermatitis lesional MCs when compared with control MC expression. Functional in vitro experiments demonstrated that a decrease in BDNF stimulation led to increased secretion rates for stem cell factor and IL-8 in HaCaT keratinocytes.

CONCLUSION

The demonstration of a decreased level of BDNF gene transcription in lesional MCs points to a differential regulation of MC-released neutrotrophins in cutaneous allergic inflammation. Topically administered neurotrophin receptor-modulating compounds should be receptor target specific and not universally acting in diseases such as atopic dermatitis or allergic asthma.

Neurokinin-1 receptor activation induces reactive oxygen species and epithelial damage in allergic airway inflammation

BACKGROUND

An induction of reactive oxygen species (ROS) is characteristic for inflammation but the exact pathways have not been identified for allergic airway diseases so far.

OBJECTIVE

The aim of this study was to characterize the role of the tachykinin NK-1 receptor on ROS production during allergen challenge and subsequent inflammation and remodelling.

METHODS

Precision-cut lung slices of ovalbumin (OVA)-sensitized mice were cultivated and ROS-generation in response to OVA challenge (10 microg/mL) was examined by the 2',7'-dichloroflourescein-diacetate method. Long-term ROS effects on epithelial proliferation were investigated by 5-bromo-2'-deoxyuridine incorporation (72 h). In vivo, the results were validated in OVA-sensitized animals which were treated intra-nasally with either placebo, the tachykinin neurokinin 1 (NK-1) receptor antagonist SR 140333 or the anti-oxidant N-acetylcystein (NAC) before allergen challenge. Inflammatory infiltration and remodelling were assessed 48 h after allergen challenge.

RESULTS

ROS generation was increased by 3.7-fold, which was inhibited by SR 140333. [Sar(9),Met(11)(O(2))]-Substance P (5 nM) caused a tachykinin NK-1 receptor-dependent fourfold increase in ROS generation. Epithelial proliferation was decreased by 68% by incubation with [Sar(9),Met(11)(O(2))]-SP over 72 h. In-vivo, treatment with SR 140333 and NAC reduced epithelial damage (91.4% and 76.8% vs. placebo, respectively, P<0.01) and goblet cell hyperplasia (67.4% and 50.1% vs. placebo, respectively, P<0.05), and decreased inflammatory cell influx (65.3% and 45.3% vs. placebo, respectively, P<0.01).

CONCLUSION

Allergen challenge induces ROS in a tachykinin NK-1 receptor-dependent manner. Inhibition of the tachykinin NK-1 receptor reduces epithelial damage and subsequent remodelling in vivo. Therefore, patients may possibly benefit from treatment regime that includes radical scavengers or tachykinin NK-1 receptor antagonists.

Neuronal plasticity of the “brain–skin connection”: stress-triggered up-regulation of neuropeptides in dorsal root ganglia and skin via nerve growth factor-dependent pathways

Emerging research indicates that central-nervous stress perception is translated to peripheral tissues such as the skin not only via classical stress hormones but also via neurotrophins and neuropeptides. This can result in neurogenic inflammation, which is likely to contribute to the triggering and/aggravation of immunodermatoses. Although the existence of such a "brain-skin connection" is supported by steadily increasing experimental evidence, it remains unclear to which extent perceived stress affects the sensory "hardwiring" between skin and its afferent neurons in the corresponding dorsal root ganglia (DRG). In this paper, we provide experimental evidence in a murine model of stress (exposure of C57BL/6 mice to sound stress) that stress exposure, or intracutaneous injection of recombinant nerve growth factor (NGF) to mimic the skin's response to stress, up-regulate the percentage of substance P (SP)+ or calcitonin gene-related peptide (CGRP)+ sensory neurons in skin-innervating DRG. Further, we show that the number of SP+ or CGRP+ sensory nerve fibers in the dermis of stressed C57BL/6 mice is significantly increased. Finally, we document that neutralization of NGF activity abrogates stress-induced effects on the percentage of SP+ and CGRP+ sensory neurons in skin-innervating DRG as well as on dermal sensory nerve fibers. These data suggest that high stress perception results in an intense cross talk between the skin and skin-innervating DRG, which increases the likelihood of NGF-dependent neurogenic skin inflammation by enhancing sensory skin innervation.

Gene and protein expression of protease-activated receptor 2 in structural and inflammatory cells in the nasal mucosa in seasonal allergic rhinitis

BACKGROUND

Protease-activated receptor 2 (PAR 2) has been shown to be responsible for trypsin and mast cell tryptase-induced airway inflammation. Here, the present study aimed to explore the expression of PAR 2 in the nasal mucosa of seasonal allergic rhinitis (SAR).

METHODS

Study subjects were recruited for the study by medical history, physical examination and laboratory screening tests. Using immunohistochemistry, laser-assisted cell picking and subsequently real-time PCR, nasal mucosa biopsies of SAR patients were investigated for PAR 2 gene and protein expression in complex tissues of the nasal mucosa.

RESULTS

Gene and protein expression of PAR 2 was firstly detected in nasal mucosa of SAR patients. The relative gene expression level of PAR 2 was significantly increased in complex tissues of the nasal mucosa of SAR (6.21+/-4.02 vs. controls: 1.38+/-0.86, P=0.004). Moreover, PAR 2 mRNA expression in epithelial cells (SAR: 4.78+/-4.64 vs. controls: 0.84+/-0.61, P=0.003) but not in mucus (SAR: 1.51+/-1.15 vs. controls: 1.35+/-1.02, P=0.78) and endothelial cells (SAR: 1.20+/-0.57 vs. controls: 1.73+/-1.30, P=0.5) was found to be significantly changed in the nasal mucosa in SAR. Using double immunohistochemistry the present study demonstrated that the total numbers of mast cells (P=0.0003) and eosinophils (P=0.03) and the numbers of eosinophils expressing PAR 2 (P=0.006) were significantly elevated in the nasal mucosa of SAR compared with the controls.

CONCLUSION

The abundant presence and distribution of gene and protein expression of PAR 2 in different cell types in the nasal mucosa under normal situation, the increased expression of PAR 2 in epithelial cells and the increased number of eosinophils with PAR 2 suggest that PAR 2 may contribute to the pathogenesis of allergic diseases such as SAR.

Effect of stress on eotaxin and expression of adhesion molecules in a murine model of allergic airway inflammation

Recently we have shown that sound stress enhances allergic airway inflammation in a combined murine model. In the current study we investigated mediating factors and early kinetics of stress exacerbated allergic airway inflammation. Stress significantly increased allergen induced airway inflammation as identified by leukocyte numbers in BAL fluids. Eotaxin levels from stressed mice were significantly higher 24 h after stress. No differences were found for vascular or cellular adhesion molecule expression or cytokine levels. Our data indicate that the effect of stress on allergic airway inflammation might be mediated by the chemoattractant eotaxin, while Th2 cytokines and expression of adhesion molecules seem not to be differently regulated in stressed and non-stressed mice.

Tachykinins in the respiratory tract

Tachykinins as substance P and neurokinin A belong to a family of peptides, which are released from airway nerves after noxious stimulation. They influence numerous respiratory functions under both normal and pathological conditions including the regulation of airway smooth muscle tone, vascular tone, mucus secretion and immune functions. For the most part the synthesis/release of tachykinins is associated with neuronal cells; nevertheless, inflammatory and immune cells can synthesize and release tachykinins under certain physiological conditions. Moreover, this second cellular source of tachykinins may play an important role in inflammatory airway diseases such as bronchial asthma or chronic obstructive pulmonary disease (COPD). Dual tachykinin (NK1 and NK2) receptor antagonists demonstrate a significant bronchoprotection and a possible future role in the development of novel therapeutic approaches. In addition, NK3 receptors could also possess a bronchoprotective action, however, their presence in the human respiratory tract still needs to be confirmed. The family of tachykinins has recently been extended by the discovery of a third tachykinin gene that encodes the previously unknown NK1 receptor selective tachykinins hemokinin 1, endokinin A and B. Together with other novel tachykinin peptides such as C14TKL-1 and virokinin further research is required to define their respiratory biological role in health and disease.

Allergic airway inflammation induces tachykinin peptides expression in vagal sensory neurons innervating mouse airways

BACKGROUND

Allergic airway inflammation has been shown to induce pro-inflammatory neuropeptides such as tachykinin peptides substance P (SP) and neurokinin A (NKA) together with related peptide like calcitonin gene-related peptide (CGRP) in nodose sensory neurons innervating guinea-pig airways.

OBJECTIVE

The present study was designed to examine the effects of allergen sensitization and challenge on the SP/NKA expression in the jugular-nodose ganglion neurons innervating the murine airways.

METHODS

Using retrograde neuronal tracing technique in combination with double-labelling immunohistochemistry, the expression of SP/NKA was investigated in a murine model of allergic airway inflammation.

RESULTS

Allergic airway inflammation was found to induce the expression of SP/NKA (13.2+/-1.43% vs. 5.8+/-0.37%, P<0.01) in large-diameter (>20 microm) vagal sensory neurons retrograde labelled with Fast blue dye from the main stem bronchi.

CONCLUSION

Based on the induction of tachykinins in airway-specific large-sized jugular-nodose ganglia neurons by allergic airway inflammation, the present study suggests that allergen sensitization and challenge may lead to de novo induction of tachykinins in neurons. This may partly contribute to the pathogenesis of airways diseases such as allergic airway inflammation.

Stress induces substance P in vagal sensory neurons innervating the mouse airways

BACKGROUND

Tachykinins-like substance P (SP) have been shown to play an important role in initiating and perpetuating airway inflammation. Furthermore, they are supposed to be released into tissues in response to stress.

OBJECTIVE

The aim of this study was to investigate the effects of stress alone or in combination with allergic airway inflammation on SP expression in sensory neurons innervating the mouse airways.

METHODS

Balb/c mice were systemically sensitized to ovalbumin (OVA), followed by allergen aerosol exposure, and compared with non-sensitized controls. Additionally, OVA-sensitized and -challenged and non-sensitized mice were exposed to sound stress. SP expression in airway-specific and overall vagal sensory neurons of the jugular and nodose ganglion complex was analysed using retrograde neuronal tracing in combination with immunohistochemistry. Preprotachykinin A (PPT-A) mRNA, the precursor for SP, was quantified in lung tissue by real-time PCR. Bronchoalveolar lavage (BAL) fluid was obtained, and cell numbers and differentiation were determined.

RESULTS

Stress and/or allergic airway inflammation significantly increased SP expression in retrograde-labelled vagal sensory neurons from the mouse lower airways compared with controls [stress: 15.7+/-0.8% (% of retrograde-labelled neurons, mean+/-SEM); allergen: 17.9+/-0.4%; allergen/stress: 13.1+/-0.7% vs. controls: 6.3+/-0.3%]. Similarly, SP expression increased in overall vagal sensory neurons identified by the neuronal marker protein gene product (PGP) 9.5 [stress: 9.3+/-0.6% (% of PGP 9.5-positive neurons, means+/-SEM); allergen: 12.5+/-0.4%; allergen/stress: 10.2+/-0.4% vs. controls: 5.1+/-0.3%]. Furthermore, stress significantly increased PPT-A mRNA expression in lung tissue from OVA-sensitized and -challenged animals, and immune cells were identified as an additional source of SP in the lung by immunohistochemistry. Associated with enhanced neuronal SP expression, a significantly higher number of leucocytes were found in the BAL following allergen exposure. Further, stress significantly increased allergen-induced airway inflammation identified by increased leucocyte numbers in BAL fluids.

CONCLUSION

The central event of sound stress leads to the stimulation of SP expression in airway-specific neurons. However, in sensitized stressed mice an additional local source of SP (probably inflammatory cells) might enhance allergic airway inflammation.

[Airway sensory nerve and tachykinins in asthma and COPD]

The airway nerve has gained importance in the field of respiratory research as it is known to have the capacity to release numerous mediators which can cause pulmonary effects in the airways. Meanwhile, a broad range of stimuli including capsaicin, bradykinin, hyperosmolar saline, tobacco smoke, allergens, ozone, inflammatory mediators and cold dry air have been shown to activate sensory nerve fibres to release neuropeptides such as the tachykinins substance P (SP) and neurokinin A (NKA) to mediate neurogenic inflammation. SP is synthesized in cell bodies of airway neurons of the trigeminal, jugulare and nodose ganglia. Following their release, tachykinins are degraded by neutral endopeptidase (NEP) and an angiotensin-converting enzyme. Tachykinins have been proposed to play an important role in human respiratory diseases such as bronchial asthma und chronic obstructive diseases (COPD) as they have been shown to have potent effects on the tone of airway smooth muscle, airway secretions, bronchial circulation and on inflammatory and immune cells by activation of the neurokinin-1 (NK-1) and neurokinin-2 (NK-2) receptors. Recently, new tachykinins such as virokinin and hemokinin were identified and characterised. Different aspects of the neurogenic inflammation have been well studied in animal models of allergic airway inflammation, but only little is known about the role of neurogenic airway inflammation in human diseases. To address the precise role of tachykinins and airway sensory nerves in human asthma und COPD, experiments on sensory nerve sensitisation and neuro-immune interaction have to be carried out in future studies.

Transcriptional up-regulation of histamine receptor-1 in epithelial, mucus and inflammatory cells in perennial allergic rhinitis

BACKGROUND

Histamine receptors play an important role in the pathogenesis of nasal allergy. Activation of histamine receptor 1 (H1R) and 2 (H2R) can cause allergic symptoms which can be blocked effectively by antihistamines. H1R and H2R transcript levels have been found to be up-regulated in perennial - but not in seasonal - allergic rhinitis (AR). The present study aimed to explore H1R and H2R expression in complex tissues of the nasal mucosa of perennial allergic rhinitis (PAR).

METHODS

Ten patients with PAR and 13 non-AR subjects were recruited for the study by medical history, physical examination and laboratory screening tests. In this study, we have analysed single cells dissected from the nasal mucosa biopsies by laser-assisted microdissection. H1R mRNA expression was analysed in different cell types such as epithelial, endothelial, mucus and inflammatory cells isolated from the nasal mucosa of PAR in comparison with non-AR subjects.

RESULTS

H1R mRNA gene expression level was significantly increased in the nasal mucosa of PAR in comparison with non-AR (P<0.0001). H1R mRNA was significantly elevated in epithelial (P<0.001) and mucus cells (P<0.05) of PAR in comparison with non-AR whereas H1R gene expression levels in endothelial cells between both groups were not changed (P=0.23). Interestingly, inflammatory cells in the nasal mucosa of PAR patients were also strongly expressed H1R mRNA (P<0.001).

CONCLUSION

The present study indicates that PAR alters the expression of H1R mRNA in epithelial, mucus and inflammatory cells of the nasal mucosa and but not in endothelial cells. Therefore, epithelial, mucus and inflammatory cells may play an important role in histamine-mediated allergic airway inflammation in PAR.

Parental tobacco smoking is associated with augmented IL-13 secretion in children with allergic asthma

BACKGROUND

Exposure to environmental tobacco smoke (ETS) has been shown to increase symptoms of allergic bronchial asthma, but direct effects on the expression of inflammatory markers have not been demonstrated thus far.

OBJECTIVE

The aim of this study was to assess the correlation of ETS exposure with the expression of proinflammatory mediators in airway secretions, including IFN-gamma and IL-12, as well as IL-5 and IL-13, in allergic asthmatic schoolchildren and healthy control subjects.

METHODS

By using the nasopharyngeal aspiration technique, airway secretions were collected from 24 atopic children with asthma (age, 6-16 years) and 26 healthy control subjects, and the concentration of cytokines was measured with immunoenzymatic methods.

RESULTS

IL-13 levels were highly increased in patients with asthma (P < .005), and parental tobacco smoke resulted in a significant increase in airway IL-13 secretion in these children compared with that seen in nonexposed children and healthy control subjects (median, 860 pg/mL vs 242 pg/mL and 125 pg/mL, respectively). Furthermore, a positive correlation between IL-13 levels and serum IgE concentrations (r(s) = 0.55) was found in children with allergic asthma.

CONCLUSIONS

These results indicate that ETS augments the expression and secretion of IL-13 in allergic asthma and that nasopharyngeal aspiration is a suitable method to assess cytokine measurements in airways in children. Measurements of IL-13 in secretions might be taken into account as a noninvasive marker of airway inflammation and to assess the detrimental effects of ETS.

Regulation of NGF and BDNF by dexamethasone and theophylline in human peripheral eosinophils in allergics and non-allergics

BACKGROUND

Recent studies have shown that the neurotrophins NGF and BDNF are produced by eosinophils. The influence of neurotrophins in allergic diseases including asthma has been described. The regulation by pharmacological substance remains unclear.

OBJECTIVES

The aim of this study was to assess whether approved pharmacological substances in the treatment of asthma such as corticosteroids or theophylline regulate neurotrophins on a cellular level.

METHODS

Eosinophils were purified by negative immunoselection from allergics and non-allergic donors. Eosinophils were incubated with dexamethasone and theophylline and supernatants were collected for measurement of neurotrophic factors. The content of neurotrophins in eosinophil lysates was determined by ELISA. Regulation of stored NGF and BDNF was demonstrated by Western-blotting and flow cytometry while influence on transcription level was demonstrated by RT-PCR.

RESULTS

Eosinophils produce and release the neurotrophins NGF and BDNF at different levels in allergics and non-allergics. Dexamethason lead to a significant downregulation of NGF in eosinophils of allergics. The levels of BDNF were not significantly reduced. Theophylline did not influence the levels of NGF nor BDNF significantly.

CONCLUSIONS

The production of the neurotrophin NGF was downregulated by an established substance such as dexamethasone. This might further contribute to the pharmacological potential of corticosteroids in allergic asthma.

Protease-activated receptor 2 expression in trigeminal neurons innervating the rat nasal mucosa

Protease-activated receptor 2 (PAR2) is activated by trypsin and mast cell tryptase to induce widespread inflammation by unknown mechanisms. Trypsin and tryptase were shown to activate sensory neurons to release substance-P and related peptides to mediate neurogenic inflammation. In the present study, the expression of PAR2 and tachykinins were investigated in rat trigeminal neurons that were identified by retrograde labeling with rhodamine dye from the nasal mucosa by using neuronal tracing in combination with immunohistochemistry. We found that large subpopulation of all trigeminal neurons (43.5+/-2.6%) identified by the pan-neuronal marker PGP 9.5 were stained with PAR2-immunoreactivity. Of all trigeminal neurons, 7.5+/-2.1% were immunoreactive for tachykinins and PAR2, and only 3.9+/-1.7% of all trigeminal neurons expressed tachykinins, but not PAR2-immunoreactivity. The present study also found that a large number trigeminal neurons innervating the nasal mucosa expressed PAR2-immunoreactivity. Of the rhodamine-labeled trigeminal neurons, 52.5+/-1.8% were immunoreactive for only PAR2 expression, 7.3+/-1.9% contained tachykinins and PAR2, and 3.1+/-0.4 of the rhodamine-labeled trigeminal neurons were non-immunoreactive PAR2, but were positive for tachykinins-immunoreactivity. In conclusion, based on the co-localization of PAR2 and tachykinins in trigeminal sensory neurons innervating the nasal mucosa, the present study suggests that, following an activation of PAR2 receptor in tachykinergic neurons by trypsin and mast cell tryptase, there may be a triggering of tachykinin-mediated phenomena such as neurogenic inflammation in allergic or non-allergic rhinitis.

Expression of tyrosine hydroxylase and neuropeptide tyrosine in mouse sympathetic airway-specific neurons under normal situation and allergic airway inflammation

BACKGROUND

The traditional neurotransmitter catecholamine and the neuropeptide tyrosine in sympathetic airway nerves have been proposed to be involved in the pathogenesis of airway diseases.

OBJECTIVE

The aim of the present study was to investigate the effect of allergic airway inflammation on the expression of catecholamine enzyme tyrosine hydroxylase (TH), neuropeptide tyrosine (NPY) and tachykinins in mouse sympathetic airway ganglia.

METHODS

Using neuronal tracing in combination with immunohistochemistry, the present study was designed to characterize TH, NPY and tachykinin profiles of superior cervical (SCG) and stellate ganglia after allergen challenge.

RESULTS

The vast majority of fast blue-labelled SCG neurons (allergen: 97.5+/-1.22% (mean+/-SEM) vs. controls: 94.5+/-1.48%, P=0.18) and stellate neurons (allergen: 95.3+/-1.01% vs. controls: 93.6+/-1.33%, P=0.34) were immunoreactive for TH. Of the TH immunoreactive and fast blue-labelled SCG neurons, 52.0+/-1.01% allergen vs. 51.2+/-3.58% controls (P=0.83) and stellate neurons, 57.3%+/-0.97 allergen vs. 56.4+/-1.65% controls (P=0.64) were positive for TH only but not NPY, whereas 45.3+/-1.05% allergen vs. 43.3+/-1.18% controls (P=0.47) of fast blue-labelled SCG neurons and 37.9+/-0.86% allergen vs. 37.1+/-1.24% controls (P=0.62) of fast blue-labelled stellate neurons were immunoreactive for both TH and NPY immunoreactivities. There was a trend of an increase, but not significant one, in the percentage of TH-/NPY-immunoreactive and fast blue-labelled neurons in allergen-treated animals in comparison with the controls. Tachykinins, however, were not expressed by sympathetic neurons and were also not induced in sympathetic neurons after allergen challenge.

CONCLUSION

The present study indicates that allergic airway inflammation does not alter the expression of noradrenalin and NPY in sympathetic ganglia and also shows that sympathetic neurons do not respond to allergic airway inflammation with tachykinins induction. However, a participation of catecholamine and NPY in the pathogenesis of allergic airway inflammation cannot be excluded in the present study as a higher neurotransmitter output per neuron following allergen challenge could be possible.

Dopamine type 2 receptor expression and function in rodent sensory neurons projecting to the airways

Agonists of the dopamine receptors have been demonstrated to have bronchodilatory properties in pathologically constricted airways. The mechanism by which these agonists induce bronchodilatation is thought to involve airway sensory nerves. In this study, the expression and function of dopamine D(2) receptor were examined in sensory ganglia supplying the airways. Neuronal dopamine D(2) receptor mRNA expression was demonstrated by single-cell RT-PCR following laser-assisted microdissection. The projection of the neurons to the airways was confirmed by retrograde neuronal labeling. In functional studies, dopamine D(2) receptor agonists (AR-C65116AB and ropinirole) inhibited intraneuronal calcium mobilization in rat capsaicin-sensitive primary sensory neurons and capsaicin-induced plasma extravasation in the rat trachea. Our results provide support to the hypothesis that dopamine D(2) receptor activation inhibits neurogenic inflammation and proinflammatory reflex responses.

Expression of substance P and nitric oxide synthase in vagal sensory neurons innervating the mouse airways

INTRODUCTION

Airway sensory nerves have the capacity to release neuromediators such as substance P and nitric oxide to control airway functions. The aim of the present study was to investigate substance P and neuronal nitric oxide synthase (NOS-1) expression in airway-specific sensory neurons.

METHODS

Airway-projecting neurons in the jugular-nodose ganglia were investigated for NOS-1 and substance P expression by neuronal tracing and double-labelling immunoreactivity.

RESULTS

Of the Fast blue labelled neurons, 14.6+/-1.8% (mean+/-S.E.M.) were immunoreactive only for NOS-1, 3.0+/-0.3% for NOS-1 and substance P, 2.7+/-0.3% only for substance P, and 79.7+/-1.7% of the labelled neurons were nonimmunoreactive for substance P or NOS-1 but were partly positive for I-B4-lectin-binding. Fast blue labelled NOS and/or substance P-positive neurons were small to medium sized (<20 microm).

CONCLUSION

Based on the expression of substance P and nitric oxide synthase in airway neurons, the present study suggests that there may be substance P and NO biosynthesis and release following a peripheral activation of the afferents, there could be a triggering of substance P and NO-mediated phenomena, including those related to airway inflammation, such as plasma extravasation and vasodilatation.