Indices of nonspecific bronchial reactivity in severe asthma phenotype determination in schoolchildren

OBJECTIVE

Introduction: Severe asthma phenotype is characterized by peculiarities of inflammatory process in the airways and consequently hypersensitivity and bronchial lability. The aim: The study aims at determining the diagnostic value of bronchial lability indices in identifying severe bronchial asthma phenotype compared to the moderate variant of disease in schoolchildren.

PATIENTS AND METHODS

Materials and methods: We formed two clinical groups of observation, the first clinical group included 57 children with severe asthma phenotype, the second clinical group included 65 patients with moderate disease course. Bronchial lability was determined by evaluating their response to dosed physical activity (bronchospasm index) and shortacting β2-agonist inhalation (200 mcg of salbutamol - bronchodilation index).

RESULTS

Results: Despite the lack of probable differences in average bronchospasm index in children of comparison groups, patients with severe bronchial asthma tended to more pronounced bronchospasm after dosed physical activity. Pronounced bronchospasm after physical activity (bronchospasm index >20%) is characteristic for children with severe disease persistence. Significantly higher bronchodilation index and severe bronchodilation reaction (bronchodilation index >25%) was determined in children of the first clinical group. Statistical analysis showed that all bronchial lability indices at these distribution points in confirming severe bronchial asthma proved to be highly specific, but low-sensitive with insufficient likelihood ratio.

CONCLUSION

Conclusions: So, the use of bronchial lability indices for screening of severe asthma phenotype is justified only in combination with other parameters reflecting the characteristic phenomena of disease because of the large proportion of false negative results and insufficient likelihood ratio.

Prostaglandin E2 prevents hyperosmolar-induced human mast cell activation through prostanoid receptors EP2 and EP4

Background

Mast cells play a critical role in allergic and inflammatory diseases, including exercise-induced bronchoconstriction (EIB) in asthma. The mechanism underlying EIB is probably related to increased airway fluid osmolarity that activates mast cells to the release inflammatory mediators. These mediators then act on bronchial smooth muscle to cause bronchoconstriction. In parallel, protective substances such as prostaglandin E₂ (PGE₂) are probably also released and could explain the refractory period observed in patients with EIB.

Objective

This study aimed to evaluate the protective effect of PGE₂ on osmotically activated mast cells, as a model of exercise-induced bronchoconstriction.

Methods

We used LAD2, HMC-1, CD34-positive, and human lung mast cell lines. Cells underwent a mannitol challenge, and the effects of PGE₂ and prostanoid receptor (EP) antagonists for EP_1–4 were assayed on the activated mast cells. Beta-hexosaminidase release, protein phosphorylation, and calcium mobilization were assessed.

Results

Mannitol both induced mast cell degranulation and activated phosphatidyl inositide 3-kinase and mitogen-activated protein kinase (MAPK) pathways, thereby causing de novo eicosanoid and cytokine synthesis. The addition of PGE₂ significantly reduced mannitol-induced degranulation through EP₂ and EP₄ receptors, as measured by beta-hexosaminidase release, and consequently calcium influx. Extracellular-signal-regulated kinase 1/2, c-Jun N-terminal kinase, and p38 phosphorylation were diminished when compared with mannitol activation alone.

Conclusions

Our data show a protective role for the PGE₂ receptors EP₂ and EP₄ following osmotic changes, through the reduction of human mast cell activity caused by calcium influx impairment and MAP kinase inhibition.

Wheat-dependent, exercise-induced anaphylaxis in Thai children: a report of 5 cases

Wheat is not an uncommon cause of food-dependent, exercise-induced anaphylaxis. This study aims to describe common clinical characteristics and laboratory manifestations of the disease. Five children, aged 8-14 years were evaluated. An atopic history was found in 20% of the patients. All patients had symptoms which involved the skin and three had hypotension. Serum specific IgE for wheat was measured and showed a positive result in 2 patients. A three-day challenge protocol with an open challenge for wheat on day 1, an exercise challenge test on day 2 and another exercise challenge test on day 3 after a meal containing wheat was performed. Four patients completed the three-day challenge protocol. Anaphylaxis occurred in 2 out of 4 patients who consumed more than 100 grams of wheat prior to the exercise. The three-day challenge protocol is a definitive diagnostic tool to confirm the diagnosis of WDEIA. However, the amount of wheat used for challenging should be at least 100 grams.

Eosinophils play a major role in the severity of exercise-induced bronchoconstriction in children with asthma

Exercise-induced bronchoconstriction (EIB) was associated with eosinophilic airway inflammation, bronchial hyperresponsiveness (BHR), atopy and airway obstruction. To understand the pathogenesis of EIB, we determine whether eosinophil is more related to the mechanism of EIB than atopy, BHR and airway obstruction. This study comprised 268 asthmatic children who underwent lung function test, methacholine challenge test, exercise challenge test, and blood tests for total IgE levels and total eosinophil counts (TEC). Urine eosinophil protein X (EPX) levels after exercise were measured by using ELISA method. EIB was observed in 195 of 268 asthmatics (72.8%). Asthmatics with EIB showed significantly increased TEC (P < 0.01) and decreased log PC(20) as compared with asthmatics without EIB. Maximal percent fall in FEV(1) after exercise was significantly correlated with TEC, log IgE, FEF(25-75%), log PC(20) (P < 0.001, respectively) and FEV(1) (P = 0.013). When the same study was carried out in nonatopic asthmatics, those with EIB showed significantly increased TEC (P = 0.01) compared with those without EIB; however, log PC(20), FEV(1), and FEF(25-75%) showed no significant differences between the two groups of nonatopic asthmatics. In addition, there was a significant correlation between the severity of EIB and TEC in nonatopic asthmatics. Urine EPX/Cr levels after exercise were correlated with the severity of EIB (r = 0.238, P = 0.014). Blood eosinophils and urine EPX/Cr after exercise correlate significantly with the maximal percent fall in FEV(1) after exercise, therefore EIB may reflect a state of eosinophilic inflammation in the airway of asthmatic children.

Effect of body mass on exercise-induced bronchospasm and atopy in African children

BACKGROUND

Sensitization to allergen is common in rural populations in less affluent countries, but atopic disease is less frequent than in richer countries. Variables explaining this dichotomy may provide insight into underlying mechanisms of atopic diseases like asthma.

OBJECTIVE

To test whether risk of exercise-induced bronchospasm (EIB) in urbanized African populations is increased in association with greater skin sensitivity or increased body mass.

METHODS

A total of 3322 children were enrolled in a prevalence survey of EIB in urban and rural South Africa. Children responding positively to an exercise challenge and a random sample of children responding negatively were recruited into a case-control study (393 controls, 380 cases). Subjects were investigated by using allergen skin prick testing, anthropometry, and assay of IgE. Stools were analyzed for parasite infestation.

RESULTS

The prevalence of EIB was higher in urban (14.9%) than rural (8.9%) areas (P < .0001). The difference in risk of EIB between urban and rural subjects was associated with atopy (odds ratio [OR] for upper tertile of skin wheal diameter, 2.65; 95% CI, 1.43-4.89; P < .0001), increasing weight (OR for upper tertile of body mass index [BMI], 2.17; 95% CI, 1.45-3.26; P = .001), and affluence. Increasing BMI was also associated with a greater strength of association between specific IgE and the corresponding skin test (Dermatophagoides pteronyssinus, OR for a positive skin test result in presence of specific IgE: heavier subjects, OR, 34.6; 95% CI, 0.9-109.3; P < .0001; lighter subjects, OR, 8.05; 95% CI, 2.74-23.6; P < .001).

CONCLUSION

Increases in BMI of rural children in subsistence economies may lead to an increased prevalence of atopic disease. This observation merits further investigation in prospective studies.

Airway immunopathology of asthma with exercise-induced bronchoconstriction

BACKGROUND

Exercise-induced bronchoconstriction (EIB) is a common cause of symptoms in a subgroup of asthmatic subjects. The pathobiology that makes this group of asthmatic subjects susceptible to bronchoconstriction after a brief period of exercise remains poorly understood.

OBJECTIVE

We sought to determine whether there are differences in lower airway inflammation and production of cytokines and eicosanoids between asthmatic subjects with and without EIB.

METHODS

Two distinct groups of asthmatic subjects based on a priori definitions were identified, one with moderate-to-severe EIB and the other without significant bronchoconstriction after exercise challenge. Both groups met the definition of asthma on the basis of bronchodilator response, bronchial hyperresponsiveness, or both. A comparative immunopathology study was conducted by using induced sputum to identify differences in lower airway inflammation and production of cytokines and eicosanoids.

RESULTS

The groups had similar baseline lung function and bronchodilator response and did not have any asthma exacerbations within the prior year. The concentration of columnar epithelial cells was markedly higher in the group with EIB (1.4 x 10(5) vs 2.9 x 10(4) cells/mL, P=.01). The concentration of eosinophils was higher in the group with EIB (3.6 x 10(4) vs 4.9 x 10(3) cells/mL P=.04). Cysteinyl leukotrienes (CysLTs; 727.7 vs 151.9 pg/mL, P=.01) and the ratio of CysLTs to prostaglandin E(2) (1.85 vs 1.04, P=.002) in the airways were higher in the group with EIB.

CONCLUSION

Injury to the airway epithelium, overexpression of CysLTs, relative under production of prostaglandin E(2), and greater airway eosinophilia are distinctive immunopathologic features of asthma with EIB.

Lower airway inflammatory responses to high-intensity training in athletes

PURPOSE

There is an increased prevalence of asthma and airway hyperresponsiveness in elite athletes, particularly in swimmers. High intensity exercise may induce airway inflammation and subsequent remodelling in these subjects. Our aim was to evaluate the effects of high-intensity training on induced-sputum cell populations in elite athletes.

METHODS

Swimmers and runners with hyperresponsive airways (SH and RH), defined by a provocative concentration of methacholine inducing a 20% decrease in FEV1 (PC20) <16 mg/ml or with normoresponsive airways (PC20 > 16 mg/ml; SN, RN) to methacholine were enrolled. The mean PC20 was 2.27 mg/ml in SH (n=12), 32.2 in SN (n=10), 3.25 in RH (n=10) and 41.5 in RN (n=13). All athletes had two induced sputum analyses at one- to two-week intervals in random order: after a period of 72 hours without training, 24 hours after a training session.

RESULTS

PC20 was unchanged after training. The median % neutrophils and eosinophils in groups SH, SN, RH, and RN, respectively, were 26.5-1.6, 8.6-0.3, 28.0-0.03 and 25.5-0.1 before and 45.0-0.5, 31.1-0.4, 54.0-0.6 and 48.3-0.3 after training. While the magnitude of the increase in neutrophils was similar for all groups, it reached statistical significance (pre-post-training) only in the SH group (P = 0.039).

CONCLUSION

A one-hour session of high-intensity training was associated with an increase in airway neutrophils among hyperresponsive swimmer athletes, while airway responsiveness remained unchanged in all groups.

Involvement of vascular endothelial growth factor in exercise induced bronchoconstriction in asthmatic patients

BACKGROUND

There is evidence that the bronchial microcirculation has the potential to contribute to the pathophysiological mechanisms of exercise induced bronchoconstriction (EIB) in asthmatic subjects. Vascular endothelial growth factor (VEGF), which is highly expressed in asthmatic airways, increases vascular permeability. The relationship between VEGF levels in induced sputum and the severity of EIB in asthmatic subjects was studied.

METHODS

The concentration of VEGF in induced sputum was examined in 23 asthmatic subjects and 11 normal controls. The asthmatic subjects performed an exercise test and the % maximal fall in forced expiratory volume in 1 second (FEV(1)) was measured. Beclomethasone dipropionate (BDP) 400 micro g twice daily was administered to the asthmatic subjects for 8 weeks and the exercise test and sputum induction were repeated.

RESULTS

The concentration of VEGF in induced sputum was significantly higher in asthmatic subjects than in normal controls. There was a significant correlation between the concentration of VEGF and the % maximal fall in FEV(1) (r=0.826, p=0.0001) and between the concentration of VEGF and airway vascular permeability index (r=0.621, p=0.0037). After treatment with inhaled BDP there was a significant decrease in the concentration of VEGF in the asthmatic subjects (before treatment: 7051 (2361) pg/ml, after treatment: 4498 (2135) pg/ml, p<0.0001). The change in the concentration of VEGF was significantly correlated with the change in the % maximal fall in FEV(1) (r=0.463, p=0.031).

CONCLUSIONS

Excessive production of VEGF in asthmatic airways may contribute to the pathogenesis of EIB via increased airway vascular permeability.

Effects of single-dose fluticasone on exercise-induced asthma in asthmatic children: a pilot study

A single high dose of inhaled corticosteroid (ICS) can increase airway caliber in children with asthma attacks and laryngitis subglottica. Presumably the effect is due to the vasoconstrictive and antiedematous properties of topical steroids. Enlarged vessels have been suggested to play a role in the pathophysiology of exercise-induced bronchial obstruction (EIB). To investigate this, we evaluated the effect of a single high dose of fluticasone propionate (FP) on EIB in asthmatic children. Nine children aged 8-16 years with mild to moderate asthma were included. All children had a history of EIB, which was confirmed by an exercise test. None was taking ICS maintenance therapy. The children inhaled either a single dose of 1 mg FP or placebo on 2 separate days within 7-14 days. After inhalation, airway caliber (FEV(1)) was assessed for 4 hr before exercise. Then an exercise challenge was performed on a treadmill to assess EIB (% fall FEV(1)). A significant increase in FEV(1) was observed 1 hr after inhalation of FP compared to placebo. Response to exercise was expressed as maximal % fall in FEV(1) from baseline (% fall) and as area under the curve (AUC) of the 30-min time/response curve. The % fall FEV(1) after exercise and the AUC were significantly reduced when FP was inhaled compared to placebo inhalation (% fall 9.7% vs. 19.2%, respectively, P = 0.038 and AUC 92.0%.min vs. 205.7%.min, respectively, P = 0.03). There was considerable individual variability in reduction of EIB, with 5 out of 9 children having a clinically significant response. We conclude that a single high dose of inhaled FP has an acute protective effect on the bronchial response to exercise in a substantial proportion of asthmatic children.

Exercise-induced bronchoconstriction among Malay schoolchildren

OBJECTIVE

Exercise-induced bronchoconstriction (EIB) may be demonstrated in 60-70% of asthmatic children in temperate climates. In areas of high humidity it is postulated to be low. The aim of the study was to determine the prevalence of EIB in a population of schoolchildren with wheezing, living in the humid tropical climate of Kuala Lumpur, Malaysia.

METHOD

We performed a cross-sectional study using the International Study of Asthma and Allergies in Childhood questionnaire to identify 7-12-year-old Malay children with asthma symptoms from a primary school in central Kuala Lumpur. Sixty-five of 76 children with 'ever wheeze' performed an exercise challenge test successfully in an uncontrolled environment. A random sample of 80 schoolchildren with no history of wheeze were similarly tested as controls. The relative humidity and temperature were recorded. A fall of > 15% was considered as clinically important.

RESULTS

The prevalence of EIB in schoolchildren with 'ever wheeze' was 47.7%. The prevalence of EIB in children with 'current wheeze' was 51.6%. The prevalence of EIB in controls was 7.5%. The relative humidity during the study ranged from 41 to 90%. There was no significant relationship between different humidity levels and EIB (P = 0.58, regression analysis).

CONCLUSION

This study demonstrates that EIB is present in asthmatic children despite the highly humid tropical environment.

Self-reported symptoms and exercise-induced asthma in the elite athlete

PURPOSE

The purpose of this study was to compare self-reported symptoms for exercise-induced asthma (EIA) to postexercise challenge pulmonary function test results in elite athletes.

METHODS

Elite athletes (N = 158; 83 men and 75 women; age: 22 +/- 4.4 yr) performed pre- and post-exercise spirometry and were grouped according to postexercise pulmonary function decrements (PFT-positive, PFT-borderline, and PFT-normal for EIA). Before the sport/environment specific exercise challenge, subjects completed an EIA symptoms-specific questionnaire.

RESULTS

Resting FEV1 values were above predicted values (114--121%) and not different between groups. Twenty-six percent of the study population demonstrated >10% postexercise drop in FEV1 and 29% reported two or more symptoms. However, the proportion of PFT-positive and PFT-normal athletes reporting two or more symptoms was not different (39% vs. 41%). Postrace cough was the most reported symptom, reported significantly more frequently for PFT-positive athletes (P < 0.05). Sensitivity/specificity analysis demonstrated a lack of effectiveness of self-reported symptoms to identify PFT-positive or exclude PFT-normal athletes. Postexercise lower limit reference ranges (MN-2SDs) were determined from normal athletes for FEV1, FEF25--75% and PEF to be -7%, -12.5%, and -18%, respectively.

CONCLUSION

Although questionnaires provide reasonable estimates of EIA prevalence among elite cold-weather athletes, the use of self-reported symptoms for EIA diagnosis in this population will likely yield high frequencies of both false positive and false negative results. Diagnosis should include spirometry using an exercise/environment specific challenge in combination with the athlete's history of asthma symptoms.

Evidence of airway inflammation and remodeling in ski athletes with and without bronchial hyperresponsiveness to methacholine

Asthma-like symptoms, methacholine hyperresponsiveness, and use of asthma medication are prevalent in elite cross-country skiers. We quantitated mucosal inflammatory cell infiltration and tenascin expression in the subepithelial basement membrane in endobronchial biopsy specimens of the proximal airways from 40 elite, competitive skiers (mean: 17.5; range: 16 to 20 yr) without a diagnosis of asthma, in 12 subjects with mild asthma, and in 12 healthy controls, through immunohistochemistry and indirect immunofluorescence, respectively. All of the subjects were nonsmokers. T-lymphocyte, macrophage, and eosinophil counts were, respectively, greater by 43-fold (p < 0.001), 26-fold (p < 0.001), and twofold (p < 0.001) in skiers, and by 70-fold (p < 0.001), 63-fold (p < 0.001), and eightfold (p < 0.001) in asthmatic subjects than in controls. In skiers, neutrophil counts were more than twofold greater than in asthmatic subjects, and mast cell counts were not significantly different than in controls. Tenascin expression (as measured through the thickness of the tenascin-specific immunoreactivity band in the basement membrane) was increased in skiers (median: 6.7 microm; interquartile range [IQR]: 5.3 to 8.5 microm, p < 0.001) and asthmatic subjects (mean: 8.8 microm; IQR: 7.2 to 10.8 microm, p < 0. 001) compared with controls (mean: 0.8 microm; IQR: 0 to 3.1 microm) and did not correlate with inflammatory cell counts. Inflammatory changes were present irrespective of asthmalike symptoms, hyperresponsiveness, or atopy. Prolonged repeated exposure of the airways to inadequately conditioned air may induce inflammation and remodeling in competitive skiers.

Bronchoscopy and bronchoalveolar lavage findings in cross-country skiers with and without "ski asthma"

Bronchial hyperresponsiveness to methacholine with asthma-like symptoms ("ski asthma") is frequent in elite cross-country skiers. To further the understanding of "ski asthma", 10 nonasthmatic, nonatopic controls and 30 adolescent elite skiers were investigated by bronchoscopy and bronchoalveolar lavage (BAL). Nine skiers were atopic without allergy symptoms. Compared with controls, the macroscopic inflammatory index in the proximal airways in skiers was three-fold greater (median (interquartile range) 3.0 (2.0-5.0) versus 1.0 (0.8-2.3), p=0.008). In the BAL fluid, skiers had significantly greater total cell (p<0.05) and percentage lymphocyte (p<0.01) and mast cell counts (p<0.05). Neutrophil and eosinophil counts were not significantly different and eosinophil cationic protein was not detected. Tumour necrosis factor-alpha and myeloperoxidase were detected in 12 (40%) and six (20%) skiers, respectively. In skiers with ski asthma, the inflammatory index was greater than in nonasthmatic skiers. Lymphocyte subtypes and activation markers, and concentration of albumin, fibronectin and hyaluronan were not different from those in controls. Cross-country skiers have a minor to moderate degree of macroscopic inflammation in the proximal airways at bronchoscopy and a bronchoalveolar lavage fluid profile which differs in several respects from healthy controls. Skiers with ski asthma tend to show even higher degrees of bronchial inflammation.

Response of nose and bronchi to exercise in asthma and rhinitis: similarities and differences

The response of asthmatic patients to exercise differs from that of healthy subjects, and the mechanisms responsible for the exercise-induced bronchoconstriction in the former group remain uncertain. The severity of bronchospasm may be related to water loss from the respiratory tree, but there are conflicting explanations for this. The response of the nose to exercise, in healthy subjects or in patients with asthma and rhinitis, has been the subject of few investigations, but a recent study found that the nose responds in a different fashion to the bronchi in patients with rhinitis and asthma. The bronchial tree responds by narrowing, while the nose becomes more patent. There is evidence that the bronchi are the main sites of airway narrowing in exercise-induced bronchoconstriction, while there can also be simultaneous tracheal dilatation. In addition, it now appears that the nasal response to exercise in all subjects parallels that of the trachea. In total, the results suggest that different mechanisms are responsible for regulating the patency of the upper and lower airways.

Airway and tissue responses during hyperpnea-induced constriction in guinea pigs

It has been reported that hyperpnea-induced bronchoconstriction in guinea pigs is a potential model for exercise-induced asthma in humans. On the basis of recent studies that show increases in tissue resistance after allergen exposure in sensitized rats, we hypothesized that lung tissues might also be involved in the pathophysiology in this asthma model. We measured tracheal pressure (Ptr) and alveolar pressure (PA) using alveolar capsules in open-chested, mechanically ventilated (respiratory frequency [f] = 1 Hz, tidal volume [VT] = 9 ml/kg, positive end-expiratory pressure [PEEP] = 4 cm H2O) guinea pigs under control conditions (regular breathing of warm, humidified air) and after dry gas hyperpnea challenge (HC, mixture of 95% O2 and 5% CO2, 150 breaths/min, 7 min). We calculated lung elastance (EL) and resistance of lung (RL), tissue (Rti), and airway (Raw) by fitting the equation of motion to changes in Ptr and PA. To assess the effects of volume history, we applied a single deep inflation (three times VT) in five HC animals. We performed morphometric analysis in five control and five HC animals, freezing the lungs with liquid nitrogen and processing the tissues via freeze substitution. HC significantly increased RL, Rti, Raw, and EL (424 +/- 62, 771 +/- 230, 287 +/- 33, 259 +/- 31% baseline, respectively). A deep inflation reduced RL, Rti, Raw, and EL by 30 +/- 4, 31 +/- 4, 29 +/- 6, 23 +/- 5%, respectively. In HC animals, the degree of airway constriction was most prominent in the larger airways; extensive tissue distortion was also observed.(ABSTRACT TRUNCATED AT 250 WORDS)

Airway effects of local challenge with hypertonic saline in exercise-induced asthma

Hypertonicity of airway lining fluid has been suggested as the stimulus for bronchoconstriction in exercise-induced asthma. We explored the airway effects of delivering a direct hypertonic stimulus to asthmatic airways via a fiberoptic bronchoscope, comparing hypertonic saline challenge by direct instillation with local aerosol delivery. A group of 18 asthmatic subjects responsive to inhaled hypertonic saline with a history of EIA were studied; the first 9 subjects received local challenge with hypertonic saline by direct instillation, and the next 9 subjects were challenged by local aerosol delivery. A control challenge with isotonic saline by either instillation or aerosol was performed at a same bronchoscopy. Local challenge with hypertonic saline by aerosol delivery was found to be more effective in inducing local bronchoconstriction (8 of 9 subjects) than instillation (2 of 6 subjects). Paired BAL fluid samples and bronchial biopsies were obtained in total of 11 and 9 subjects, respectively. Local challenge with hypertonic saline either by instillation or aerosol produced no significant change in histamine, tryptase, or PGD2 levels in BAL fluid or mast cell numbers and degranulation in bronchial biopsies. A significant correlation was observed between histamine levels in BAL fluid and airway responsiveness to inhaled hypertonic saline (rs = -0.59, p < 0.05). Bronchial biopsies showed evidence of extensive epithelial damage; however, this was not related to airway responsiveness to inhaled hypertonic saline.

Airway inflammation and occurrence of delayed bronchoconstriction in exercise-induced asthma

We studied nine asthmatic patients with a history of exercise-induced asthma (EIA) in order to investigate whether inflammatory changes in the airways occur after exercise and are eventually associated with the development of a late-phase asthmatic response. On two separate study days, bronchoalveolar lavage (BAL), bronchial lavage (BL), and bronchial biopsy (BB) were performed 3 h after an exercise or a methacholine (MCh) challenge. On two other separate occasions, FEV1 was monitored for 12 h after identical exercise and MCh challenges not followed by BAL, BL, and BB. We found a greater percentage of eosinophils in BAL after exercise versus MCh challenge (p < 0.05). In five patients, BAL eosinophils after exercise were > or = 2% of total inflammatory and immunoeffector cells. In three of these patients an FEV1 fall > 20% of control was recorded 5 to 12 h after exercise. However, two of these patients had 2% or more eosinophils in BAL and similar late falls of FEV1 after MCh challenge. The percentage of degranulating mast cells in BB was higher (p < 0.05) after EIA than after MCh, but no significant differences were found in BL histamine and leukotrienes. We conclude that (1) exercise may enhance mast cell degranulation and eosinophilic inflammation of the airways, and (2) a delayed bronchoconstriction after exercise is not specific to EIA but is more likely the result of fluctuations in lung function associated with airway inflammation.

Airway levels of mast cell-derived mediators in exercise-induced asthma

In order to assess the role of mast cell-derived mediators in the pathogenesis of exercise-induced asthma (EIA), we completed pre- and postexercise bronchoalveolar lavage (BAL) in seven atopic subjects with EIA. The study subjects were defined as having EIA if they exhibited a greater than 15% decrease in FEV1 after completing 6 min of treadmill exercise. There were no significant differences between mean preexercise and mean postexercise mast cell-derived BAL histamine (186 +/- 67 versus 148 +/- 36 pg/ml), tryptase (4.5 +/- 2.0 versus 2.8 +/- 2.0 ng/ml), prostaglandin D2 (26 +/- 11 versus 32 +/- 25 pg/ml), or leukotriene C4 (less than 100 versus less than 100 pg/ml). In addition, mast cells present in BAL fluid after exercise contained similar amounts of cellular histamine compared with BAL mast cells obtained before exercise (preexercise BAL cellular histamine, 26.6 +/- 12.3 ng/10(6) BAL cells; postexercise BAL cellular histamine, 22.7 +/- 9.1 ng/10(6) BAL cells), indicating that depletion of preformed mast cell mediators are unlikely to account for the refractory period in EIA. This study suggests that the cellular pathogenesis of EIA (mast cell-independent) differs from current theories of the pathogenesis of extrinsic allergen-induced asthma (mast cell-dependent).

A study of exercise-induced bronchial hyperreactivity in patients with rhinosinusal pathology

Bronchial hyperreactivity is an increased response to different stimuli, with the corresponding edema, hypersecretion or dyscrinia and bronchospasm. There are many techniques to provoke bronchial hyperreactivity. The exercise challenge is a simple technique which has certain advantages so as to be chosen as a method especially for a pediatric group. In the present study, we analyzed the response to exercise in 21 children with rhinosinusal pathology but without any bronchial pathology. To evaluate this, we studied the pre- and post-exercise spirometries and airway resistances. As results, 75% of the patients presented with an increase in airway resistance (Raw) after exercise.

Enhancement of leukocyte cytotoxicity after exercise-induced asthma

We have previously shown that there were elevations of neutrophil chemotactic activity (NCA) and increases in the percentages of neutrophil and monocyte complement rosettes after exercise-induced asthma (EIA). These observations suggested that leukocyte activation may occur after EIA, possibly as a result of the release of mast-cell-associated mediators. In the present study, we have attempted to establish whether neutrophils and monocytes are functionally altered after EIA as assessed by changes in their cytotoxic capacity. Cytotoxicity was assessed by a direct visual killing assay using opsonized (complement-coated) schistosomula of Schistosoma mansoni as target organisms. Neutrophils and mononuclear cells obtained from 8 patients after exercise-induced asthma (EIA+ve) had increased cytotoxicity for opsonized schistosomula for as long as 60 min after exercise. These changes were preceded by elevations in the concentrations of serum high molecular weight NCA (which were maximal at 10 min after exercise). In asthmatic patients who did not develop exercise-induced asthma (EIA-ve), no significant increases in neutrophil or mononuclear cell killing of schistosomula, or serum NCA concentrations, were observed. There was a highly significant correlation (p less than 0.001) between the reduction in FEV1 and the increases in neutrophil cytotoxicity. In 5 EIA+ve patients, administration of disodium cromoglycate (cromolyn) prior to the exercise task inhibited both the enhancement in neutrophil and mononuclear cell cytotoxicity, as well as the elevations in circulating NCA and the reductions in FEV1.(ABSTRACT TRUNCATED AT 250 WORDS)

Combination drug therapy in children with exercise-induced bronchospasm

Fifty-three children with moderately severe asthma were studied to determine the capacity of drugs to block exercise-induced bronchospasm (EIB). All 53 children demonstrated EIB (as defined by a 20% fall in FEV1 or 30% fall in FEF25-75) while receiving therapeutic theophylline (serum level 10-20 micrograms/ml). EIB was completely blocked in 47 children by an inhaled metaproterenol 10 minutes prior to exercise, in addition to the theophylline. In six children, EIB was only partially blocked when either metaproterenol or cromolyn was added to the theophylline, but was completely blocked when all three drugs were used. A small group of children may benefit from combination therapy for EIB.

Upper airway obstruction presenting as exercise-induced asthma

A patient presented with a ten-year history of exercise-induced wheezing. After trials of metaproterenol and cromolyn failed to improve her symptoms, she was observed during exercise. She proved to have inspiratory stridor caused by collapse of the posterior aryepiglottic folds over the vocal cords during inspiration only following exercise. Symptoms primarily improved with physical conditioning. Further improvement came after treatment of her chronic rhinitis and post-nasal drip with a steroid nasal spray.