Induced sputum in children with newly diagnosed mild asthma: the effect of 6 months of treatment with budesonide or disodium cromoglycate

Using induced sputum method in clinical practice in patients with bronchial asthma

This article presents an overview of modern statements of the induced sputum method; detailed description of the methods and protocols for taking sputum in adults and children, methods for processing the obtained substance. The paper describes in detail the features of the cellular composition of induced sputum in healthy individuals and in patients with bronchial asthma, emphasizes the importance of the eosinophilia level as a prognostic and diagnostic criterion of asthma and also determines the functions of other induced sputum cells such as neutrophils, macrophages, basophils. The article is illustrated with photographs of sputum microscopy. In addition to sputum cytology, we give accent to the possibility of using other research methods such as an identification of viral and bacterial pathogens, genomics, proteomics, lipidomics, metabolomics, determination of the concentration of various mediators in the sputum supernatant. The paper presents the ideas on biochemical inflammatory markers and remodelling of the respiratory tract in asthma, which can be determined in sputum (C3a anaphylatoxin, clusterin, periostin, eosinophil-derived neurotoxin, folliculin). In addition, we summarize the information on inflammatory phenotypes of bronchial asthma, emphasize their variability and modification depending on the period of the disease, prescribed treatment, intercurrent respiratory infections, and smoking. The article also presents detailed characteristics of eosinophilic, neutrophilic, mixed and small granulocyte phenotypes of bronchial asthma, and describes the most frequent correlations of phenotypes with the severity and course of the disease, with lung function parameters and other indicators. The paper gives an account of the possibilities of using the induced sputum method for a comprehensive assessment of the course, asthma controllability and the effectiveness of drug therapy, as well as for a personalized selection of an antiinflammatory drug considering the inflammatory phenotype.

[Use of inflammatory markers for monitoring paediatric asthma]

The assessment of asthma control takes into account the symptoms, quality of life, lung function, and inflammatory markers. In the last few years, there has been a large increase in the number of publications related to the study of biomarkers in the management of paediatric asthma. Despite the large variety of inflammatory markers described in research studies, only a small group has shown to be useful in monitoring the disease. Induced sputum eosinophils offer the most solid evidence in assessing asthma control. Exhaled breath condensate and urinary leucotrienes could be useful in the future if there is standardisation in their procedures and interpretation of the results. Nitric oxide, basic eosinophil cationic protein, and bronchial biopsy with bronchoalveolar lavage, only appeared to be useful in a reduced group of patients.

The Association of Lung Function, Bronchial Hyperresponsiveness, and Exhaled Nitric Oxide Differs Between Atopic and Non-atopic Asthma in Children

Purpose

Although many previous studies have attempted to identify differences between atopic asthma (AA) and non-atopic asthma (NAA), they have mainly focused on the difference of each variable of lung function and airway inflammation. The aim of this study was to evaluate relationships between lung function, bronchial hyperresponsiveness (BHR), and the exhaled nitric oxide (eNO) levels in children with AA and NAA.

Methods

One hundred and thirty six asthmatic children aged 5-15 years and 40 normal controls were recruited. Asthma cases were classified as AA (n=100) or NAA (n=36) from skin prick test results. Lung function, BHR to methacholine and adenosine-5'-monophosphate (AMP), eNO, blood eosinophils, and serum total IgE were measured.

Results

The AA and NAA cases shared common features including a reduced small airway function and increased BHR to methacholine. However, children with AA showed higher BHR to AMP and eNO levels than those with NAA. When the relationships among these variables in the AA and NAA cases were evaluated, the AA group showed significant relationships between lung function, BHR to AMP or methacholine and eNO levels. However, the children in the NAA group showed an association between small airway function and BHR to methacholine only.

Conclusions

These findings suggest that the pathogenesis of NAA may differ from that of AA during childhood in terms of the relationship between lung function, airway inflammation and BHR.

Asymmetric dimethylarginine in exhaled breath condensate and serum of children with asthma

BACKGROUND

Asymmetric dimethylarginine (ADMA) is an endogenous inhibitor and uncoupler of nitric oxide synthase. By promoting the formation of peroxynitrite, ADMA is believed to contribute to several aspects of asthma pathogenesis (ie, airway inflammation, oxidative stress, bronchial hyperresponsiveness, and collagen deposition). The aim of the present study was to compare this mediator in healthy children and children with asthma using the completely noninvasive exhaled breath condensate (EBC) technique.

METHODS

We recruited 77 children with asthma (5-16 years of age) and 65 healthy children (5-15 years of age) who underwent EBC collection and spirometry. Serum ADMA levels and fractional exhaled nitric oxide levels were measured on the same day in a subgroup of children with asthma. EBC was collected using the Turbo-Deccs (Medivac). ADMA levels were measured using the ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) technique.

RESULTS

ADMA could be detected in the EBC of 71 subjects with asthma and 64 healthy subjects. ADMA levels in the EBC of children with asthma were significantly higher than in the healthy control subjects (median, 0.12 [interquartile range, 0.05-0.3] vs 0.07 [0.05-0.12]; P = .017), whereas no difference emerged between the children with asthma who were or were not receiving inhaled steroid treatment. No correlation was found between serum and EBC ADMA levels (P > .5).

CONCLUSIONS

We measured ADMA in EBC by UPLC-MS/MS, a reference analytical technique. Higher ADMA levels were found in children with asthma, supporting a role for this mediator in asthma pathogenesis. This oxidative stress-related mediator also seems to be scarcely affected by steroid therapy. We speculate that ADMA might be a target for new therapeutic strategies designed to control oxidative stress in asthma.

Markers of eosinophilic and neutrophilic inflammation in bronchoalveolar lavage of asthmatic and atopic children

BACKGROUND

Recent studies performing fiberoptic bronchoscopy in children have improved our understanding of asthma pathophysiology. Eosinophilic, but also neutrophilic, inflammation has been described in asthma, but the relationship with atopy was incompletely investigated. The aim of this study is to examine inflammatory cells and mediators in children with asthma compared to the appropriate controls, i.e. atopic children without asthma and children with no atopy or asthma. Moreover, asthmatic children were analysed separately based on the presence of atopy and stratified by age.

METHODS

We recruited 191 children undergoing fiberoptic bronchoscopy for appropriate indications: 91 asthmatics (aged 1.4-17 years), 44 atopics without asthma (1.6-17.8 years) and 56 nonasthmatic nonatopic controls (1.4-14 years). In bronchoalveolar lavage, total and differential cell counts and inflammatory mediators, including ECP, eotaxin, IL-8 and TNFalpha, were analysed.

RESULTS

Eosinophils and ECP levels were increased in asthmatic children when compared to controls (P = 0.002 and P = 0.01, respectively), but also atopic children without asthma had increased ECP levels compared to controls (P = 0.0001). Among asthmatic children, eosinophils and ECP levels were not different between atopic and nonatopic individuals. Neither neutrophils nor the related mediators (IL-8 and TNFalpha) differed significantly in the three groups. This pattern of inflammation was observed in both preschool and school-aged asthmatic children.

CONCLUSIONS

This study suggests that markers of eosinophilic, but not neutrophilic inflammation, are increased in asthmatic children and also in atopic children without asthma. Of interest, in asthmatic children, the activation of the eosinophilic response is not solely because of the presence of atopy.

Relationships of methacholine and adenosine monophosphate responsiveness with serum vascular endothelial growth factor in children with asthma

BACKGROUND

Airway hyperresponsiveness, which is a characteristic feature of asthma, is usually measured by means of bronchial challenge with direct or indirect stimuli. Vascular endothelial growth factor (VEGF) increases vascular permeability and angiogenesis, leads to mucosal edema, narrows the airway diameter, and reduces airway flow.

OBJECTIVE

To examine the relationships between serum VEGF level and airway responsiveness to methacholine and adenosine monophosphate (AMP) in children with asthma.

METHODS

Peripheral blood eosinophil counts, serum eosinophil cationic protein (ECP) concentrations, and serum VEGF concentrations were measured in 31 asthmatic children and 26 control subjects. Methacholine and AMP bronchial challenges were performed on children with asthma.

RESULTS

Children with asthma had a significantly higher mean (SD) level of VEGF than controls (361.2 [212.0] vs 102.7 [50.0] pg/mL; P < .001). Blood eosinophil counts and serum ECP levels significantly correlated inversely with AMP provocation concentration that caused a decrease in forced expiratory volume in 1 second of 20% (PC20) (r = -0.474, P =.01; r = -0.442, P =.03, respectively), but not with methacholine PC20 (r = -0.228, P = .26; r = -0.338, P =.10, respectively). Serum VEGF levels significantly correlated with airway responsiveness to AMP (r = -0.462; P = .009) but not to methacholine (r = -0.243; P = .19).

CONCLUSIONS

Serum VEGF levels were increased in children with asthma and were related to airway responsiveness to AMP but not to methacholine. Increased VEGF levels in asthmatic children may result in increased airway responsiveness by mechanisms related to airway inflammation or increased permeability of airway vasculature.

Anti-inflammatory drug therapy in asthma

Asthma is a disease with chronic inflammation of the airways and and-inflammatory treatment is a logical treatment. Inhaled corticosteroids [ICS] remain the cornerstone of anti-inflammatory therapy in recent international guidelines. Asthma cannot be cured by any medication: if the drug is discontinued, the disease manifestations return. This has been proven at all ages. In preschool children the diagnosis of asthma is difficult to establish. In this heterogeneous group ICS or leukotriene receptor antagonists [LTRA] are just as effective as placebo; in the future it will hopefully be possible to describe characteristics of responders. LTRA are an alternative in mild asthma, especially when mono-triggered viral related wheeze is present. Theophylline is effective and also has bronchodilatory properties, which need to be balanced against the relatively frequent side effects. The working mechanisms of anti-inflammatory asthma medications including ICS, LTRA, cromones, macrolides and theophylline are described.

The value of sputum 8-isoprostane in detecting oxidative stress in mild asthma

BACKGROUND

Exhaled nitric oxide and induced sputum eosinophils are well established as direct markers of inflammation/oxidative stress in asthma. Recently, it has been proposed that sputum 8-isoprostane concentrations may present a reliable index for measuring oxidative stress in asthmatic patients. We assessed the value of sputum 8-isoprostane in mild asthma in children and adolescents.

METHODS

Patients with newly diagnosed asthma (children, n = 23; adults, n = 14) and age-matched healthy controls (children, n = 13; adults, n = 15) were studied. Lung function was measured by spirometry, sputum was induced by hypertonic saline, and fractional exhaled nitric oxide (FeNO) was measured with standard methods. Cell differential counts were obtained from sputum slides and the concentration of 8-isoprostane was measured with an enzyme immunoassay from sputum supernatants.

RESULTS

High-quality sputum specimens could be obtained from 10 children and 10 adults, and the sputum analyses were conducted only for the representative specimens. Asthmatics had increased FeNO (children 35.5 vs. 11.9 ppb; adults 81.1 vs. 16.6 ppb; p < 0.001) and sputum eosinophils (children 2.4% vs. 1.4%; adults 10.4% vs. 0.2%; p = 0.005) compared to healthy controls. There was a significant correlation between FeNO and eosinophils (R = 0.65; p < 0.0001). Sputum 8-isoprostane was not elevated in asthmatics compared to healthy subjects (children 81.1 vs. 89.9 and adults 76.9 vs. 73.4 pg/mL) and did not correlate with lung function or other measurements of airway inflammation. However, increased 8-isoprostane levels were detected in patients with chronic obstructive pulmonary disease (n = 11, 184.7 pg/mL, used as controls for assays).

CONCLUSIONS

In agreement with earlier studies, FeNo is sensitive in detecting oxidative/nitrosative stress in asthmatic airways. However, our results suggest that 8-isoprostane may not be sensitive in reflecting oxidant burden in mild asthma.

Eosinophilic airway inflammation and the prognosis of childhood asthma

BACKGROUND

Eosinophilic airway inflammation is a key pathophysiological feature of asthma that can predict treatment response. However, the prognostic value of sputum eosinophilia is not established.

OBJECTIVE

The aim of this study was to determine the influence of induced sputum eosinophilia on the prognosis of childhood asthma.

METHODS

A cohort of children with asthma was evaluated by induced sputum analysis at inception and classified as having either eosinophilic asthma (EA) (sputum eosinophils >2.5%) or non-eosinophilic asthma (NEA). After a mean follow-up period of 5 years, eligible subjects (n=83) were contacted and 69 subjects (33 EA, 36 NEA) evaluated. The children had a mean age of 15.9 years, and 61% were male.

RESULTS

Children with EA reported more wheeze during the follow-up period (27% vs. 6% wheezed most years; P<0.0001), increased night waking during the past 12 months (28% vs. 3% reported weekly waking; P=0.01), and greater impairment of quality of life due to asthma (P=0.04). Subsequent beta2-agonist use was increased in children with EA (P=0.02), although there was no difference in corticosteroid use. In EA, subsequent forced expiratory volume in 1 s/forced vital capacity was lower (79% vs. 86%; P=0.01) and grass pollen allergy was more prevalent (77% vs. 27%; P=0.006).

CONCLUSION

In children, eosinophilic airway inflammation is associated with deteriorating asthma over time. This is consistent with the hypothesis that airway inflammation has an adverse impact on the prognosis of childhood asthma, and suggests a role for monitoring inflammation in asthma management.

Bronchial responsiveness to methacholine and adenosine 5'-monophosphate in young children with asthma: their relationship with blood eosinophils and serum eosinophil cationic protein

BACKGROUND

Bronchial hyperresponsiveness is a characteristic feature of asthma, and is usually measured by bronchial challenges using direct or indirect stimuli. Blood eosinophil numbers and serum levels of eosinophil cationic protein (ECP) are considered as indirect measures of airway inflammation in asthma. The aim of this study was to investigate whether bronchial responsiveness to adenosine 5'-monophosphate (AMP) is more closely associated with blood eosinophil markers, compared with that to methacholine, in young children with asthma.

METHODS

Methacholine and AMP bronchial challenges were performed in 4- to 6-year-old children with asthma (n = 77) and in healthy controls (n = 32), using a modified auscultation method. The end-point was defined as the appearance of wheezing and/or oxygen desaturation. The peripheral blood eosinophil counts and serum ECP concentrations were determined in each subject.

RESULTS

A positive response to methacholine (end-point concentration < or =8mg/ml) and to AMP (end-point concentration < or =200 mg/ml) was observed in 74 (96.1%) and 66 asthmatic children (85.7%), respectively. A majority of controls was unresponsive to both challenges. In the asthma group, there was no significant correlation between methacholine end-point concentration and the eosinophil counts (r = -0.111, P = 0.337) or serum ECP levels (r = -0.126, P = 0.274). In contrast, AMP end-point concentration correlated significantly with the eosinophil counts (r = -0.372, P = 0.001) and with serum ECP levels (r = -0.371, P = 0.001).

CONCLUSIONS

Our results suggest that bronchial responsiveness to AMP is more closely related to airway inflammation, compared with that to methacholine, and support the potential usefulness of AMP challenges in detecting inflammatory changes in young children with asthma.

Epithelial damage and angiogenesis in the airways of children with asthma

RATIONALE

Airway remodeling and inflammation are characteristic features of adult asthma that are still poorly investigated in childhood asthma.

OBJECTIVES

To examine epithelial and vascular changes as well as the inflammatory response in airways of children with asthma.

METHODS

We analyzed bronchial biopsies obtained from 44 children undergoing bronchoscopy for appropriate clinical indications other than asthma: 17 with mild/moderate asthma (aged 2-15 yr), 12 with atopy without asthma (1-11 yr), and 15 control children without atopy or asthma (1-14 yr). By histochemistry and immunohistochemistry, we quantified epithelial loss, basement membrane thickness, number of vessels, and inflammatory cells in subepithelium.

RESULTS

Epithelial loss and basement membrane thickness were increased in children with asthma compared with control subjects (p = 0.005 and p = 0.0002, respectively) and atopic children (p = 0.002 and p = 0.005, respectively). The number of vessels and eosinophils was increased not only in asthmatic children (p = 0.03 and p = 0.0002, respectively) but also in atopic children without asthma (p = 0.03 and p = 0.008, respectively) compared with control subjects. When we stratified the analysis according to age, we observed that children with asthma younger than 6 yr had increased epithelial loss, basement membrane thickening, and eosinophilia compared with control subjects of the same age.

CONCLUSIONS

Epithelial damage and basement membrane thickening, which are pathologic features characteristic of adult asthma, are present even in childhood asthma. Other changes, such as airway eosinophilia and angiogenesis, were also observed in atopic children without asthma. These observations suggest that pathologic changes occur early in the natural history of asthma and emphasize the concept that some of these lesions may characterize atopy even in the absence of asthmatic symptoms.

Sputum induction in children with asthma: a tertiary-center experience

Our aims were 1) to report on our experience with sputum induction (SI), and 2) to determine predictive factors associated with successful SI in asthmatic children. Children with asthma attending the chest clinic of a university teaching hospital between October 2003-December 2004 were recruited. They completed a visual analogue scale for symptom severity, and underwent physical examination, skin-prick test, exhaled nitric oxide (eNO) measurement, spirometry, and SI. Adequate sputum contained <50% squamous epithelial cells. Predictors for successful induction were evaluated using multivariate logistic regression analysis. One hundred and thirty subjects were recruited. The median age was 11.25 years (range 7.0-17.5), and the majority were boys (75%). All except two had normal percent predicted forced expired volume in 1 sec (>80%). The median eNO was 48.95 ppb. Sputum induction was successful in 93 subjects (74.5%). Sore throat and chest discomfort occurred in 20 (15%) and 8 (6%) subjects, respectively, and the procedure was prematurely terminated in three cases. Levels of eNO were found to be a predictor for successful induction (area under the ROC (receiver operator characteristics curves) curve, 0.634). Sputum induction was well-tolerated by all subjects, and was successful in 74.5% of cases. Exhaled nitric oxide may be a useful marker for successful induction.

Asthma therapy for children under 5 years of age

PURPOSE OF REVIEW

The evidence for effectiveness of currently used asthma medication for wheeze in young children is reviewed.

RECENT FINDINGS

The management of the infant and preschool child with wheezing is complicated by the uncertainty with respect to the aetiology. Difficulties in defining phenotypes and objective outcome parameters combined with the transient nature of symptoms which often resolve spontaneously have confounded many therapeutic studies. Recent studies on the effect of pharmacotherapy in wheezing infants have tried to define a more homogeneous phenotype as well as make a selection of patients that are likely to respond to the studied drug. In addition, these studies have used lung function parameters and nitric oxide as one of the outcome measurements. Studies on the nature of inflammation and the development of airway remodelling in infants and young children are done to further define phenotypes.

SUMMARY

Currently, there are no evidence-based guidelines and not even consensus statements on the right approach in pharmacological treatment of wheezing in infants and preschool children. The main issue still is the difficulty in coming to a correct diagnosis. Further studies are needed on the nature and the diagnostics of phenotypes and on the effect of early intervention.

The treatment of asthma in children: inhaled corticosteroids

The evidence that asthma is characterized by extensive inflammation of the airways has warranted the use of inhaled corticosteroid (ICS) in asthma maintenance therapy. Corticosteroid treatment, especially if high or frequent doses are required, is associated with a range of adverse effects including adrenal suppression and impairment in growth and bone metabolism. New corticosteroids are in development, including mometasone furoate, and some of these are predicted to have reduced adverse effects such as the soft steroid ciclesonide. Soft steroids are designed for delivery near to their site of action, to exert their effect and then to undergo controlled and predictable metabolism to inactive metabolites. This review points out the anti-inflammatory effects of corticosteroid in asthmatic airways and the clinical efficacy and safety of ICS in asthmatic children. The development of a soft steroid should help to achieve the aim of improving the therapeutic profile of ICS in asthma and thus alleviate the ongoing problem of poor patient compliance especially in childhood.