Childhood asthma: new insights into management

Inhaled steroid inhibits development of total and mite IgE

Serum levels of total immunoglobulin E (IgE) and allergen-specific IgE are related to asthma severity and risk factors for persistent asthma in childhood wheezing. Inhaled corticosteroids (ICS) have been the most effective therapy in children with asthma, as well as in adults. The serum levels of total and mite specific IgE in children with asthma and the effects on IgE levels of beclomethasone dipropionate (BDP) treatment on IgE levels in asthmatic children were investigated. First, a cross-sectional study of 255 children with asthma was carried out to measure IgE levels. Children under three years of age with asthma who were negative for Df-specific IgE were then treated with BDP or disodium cromoglycate (DSCG) as controls for one year. Serum IgE levels, numbers of eosinophils in peripheral blood and clinical variables were determined before and after treatment. After one-year DSCG treatment, the total IgE levels increased significantly, whereas the levels remained the same during BDP treatment. Five of 22 (23%) patients in the DSCG-treated group became positive for Df-specific IgE; however, only one of 13 (8%) in the BDP-treated group became positive. Taken together, ICS therapy may modulate the levels of total IgE and allergen-specific IgE.

Therapeutic management of allergic diseases

Allergic diseases are characterized by the activation of inflammatory cells and by a massive release of mediators. The aim of this chapter was to describe succinctly the modes of action, indications, and side effects of the major antiallergic and antiasthmatic drugs. When considering the ideal pharmacokinetic characteristics of a drug, a poorly metabolized drug may confer a lower variability in plasma concentrations and metabolism-based drug interactions, although poorly metabolized drugs may be prone to transporter-based disposition and interactions. The ideal pharmacological properties of a drug include high binding affinity, high selectivity, and appropriate association and dissociation rates. Finally, from a patient perspective, the frequency and route of administration are important considerations for ease of use.

Exercise-induced bronchospasm in children

This review will encompass definition, history, epidemiology, pathogenesis, diagnosis, and management of exercise -induced bronchospasm in the pediatric individual with and without known asthma. Exercise induced asthma is the conventional term for transient airway narrowing in a known asthma in association with strenuous exercise usually lasting 5-10 minutes with a decline in pulmonary function by at least 10%. Exercise induced asthma will be referred to as exercise induced bronchospasm in an asthmatic. Exercise-induced bronchospasm (EIB ) is the same phenomenon in an individual without known asthma. EIB can be seen in healthy individuals including children as well as defense recruits and competitive or elite athletes. The diagnosis with objective exercise challenge methods in conjunction with history is delineated. Management is characterized with pharmacotherapy and non pharmacotherapeutic measures for underlying asthma as well as exercise induced bronchospasm and inhalant allergy. Children can successfully participate in all sports if asthma is properly managed.

Asthma

Asthma has been recognized as a disease since the earliest times. In the Corpus Hippocraticum, Hippocrates used the term “ασθμα” to indicate any form of breathing difficulty manifesting itself by panting. Aretaeus of Cappadocia, a well-known Greek physician (second century A.D.), is credited with providing the first detailed description of an asthma attack [13], and to Celsus it was a disease with wheezing and noisy, violent breathing. In the history of Rome, we find many members of the Julio-Claudian family affected with probable atopic respiratory disorders: Caesar Augustus suffered from bronchoconstriction, seasonal rhinitis as well as a highly pruritic skin disease. Claudius suffered from rhinoconjunctivitis and Britannicus was allergic to horse dander [529]. Maimonides (1136–1204) warned that to neglect treatment of asthma could prove fatal, whereas until the 19th century, European scholars defined it as “nervous asthma,” a term that was given to mean a defect of conductivity of the ninth pair of cranial nerves.

Primary prevention of allergic diseases: current concepts and mechanisms

: Atopic diseases, the new "epidemic of the twenty-first century" and a central health problem of industrial nations, call for the development of innovative primary prevention strategies. The present review provides an overview of current experimental and immunomodulatory procedures and their underlying mechanisms.

Increased leukotriene E4 in the exhaled breath condensate of children with mild asthma

BACKGROUND

Chronic airway inflammation is a feature of asthma. Increased levels of cysteinyl leukotrienes (cys-LTs; leukotriene [LT]C(4), LTD(4), LTE(4)) have been shown in the exhaled breath condensate (EBC) of children with moderate-to-severe asthma. The aim of this study was to examine the relationship between EBC cys-LTs (LTE(4)) levels and bronchial hyperreactivity in children with mild asthma in order to evaluate the clinical utility of measuring EBC cys-LTs levels.

METHODS

We measured LTE(4) levels in the EBC of children aged 8 to 18 years, including healthy nonasthmatic children (n = 6) and children with mild asthma (n = 37). Patients with mild asthma were classified into the following three groups: group 1, participants who had been asymptomatic (no wheezing/symptoms of asthma) for > 6 months prior to examination (n = 12); group 2, participants who were asymptomatic but had had wheezing/symptoms of asthma within 6 months before examination (n = 18); and group 3, patients with current wheeze and/or mild symptoms of asthma exacerbation at the time of examination.

RESULTS

Exhaled LTE(4) levels were increased in all children with mild asthma compared with nonasthmatic control subjects (5.69 +/- 9.62 pg/20 min vs 0.74 +/- 0.79 pg/20 min, p < 0.05) [mean +/- SD]. In particular, the EBC LTE(4) levels in group 2 (4.99 +/- 6.70 pg/20 min) and group 3 (14.66 +/- 17.11 pg/20 min) were increased compared with control subjects and group 1 (1.50 +/- 1.69 pg/20 min). The EBC LTE(4) levels negatively correlated with the provocative concentration of methacholine causing a 15% fall in FEV(1) (r = - 0.454, p = 0.012).

CONCLUSION

EBC cys-LTs may be useful as a noninvasive marker assessing airway inflammation and hyperreactivity in children with asthma.

Advances in the management of pediatric asthma: a review of recent FDA drug approvals and label updates

Children have the highest prevalence of asthma of any age group. In the United States during 2001, there were 12.6 million physician and hospital outpatient visits for asthma treatment, of which almost 5 million involved children 18 years and younger. Therapeutic advances in pediatric asthma could improve patient outcomes and potentially reduce the burden on health care systems. Efforts to obtain efficacy and safety data in pediatric populations and develop pediatric formulations of asthma treatments have been encouraged by the FDA and clinicians. This article reviews the newest additions to asthma therapies approved for use in children, including an inhaled corticosteroid, some long-acting beta2-agonists, some leukotriene-receptor blockers, and a single-isomer, short-acting beta2-agonist.

Exhaled nitric oxide in paediatric asthma

Assessment of airway function is difficult in young children with asthma, and in addition, only reflects the status of the disease at the time of the measurement. Thus, there is increasing interest in monitoring airway inflammation in asthma, which may provide a longer term assessment of disease activity. Most methods of assessing asthmatic inflammation are invasive, and are not feasible in the paediatric population. This review discusses exhaled nitric oxide as a marker of asthmatic inflammation, and compares it with other recognized markers. Exhaled nitric oxide has the potential to become a noninvasive method of assessing asthma control in the paediatric population.

[Asthma treatment in childhood: from guidelines to practice]

Aims for the management of asthma in children are to optimize quality of life and to maintain normal lung functions. International guidelines recommend rapid-acting inhaled beta2-agonist as needed in children with intermittent asthma. Once asthma is persistent, mild, moderate or severe, daily long-term therapy with inhaled corticosteroids should be started. Association with long-acting inhaled beta2-agonist or leukotriene inhibitors are required in children not enough controlled with inhaled corticosteroids alone. Management of the asthmatic child should not be restricted to antiasthmatic drug prescription but should include patient and patient's family education as well as adequate health of life.

Pharmacokinetic properties and tolerability of single-dose terbutaline in patients with severe asthma treated in the pediatric intensive care unit

BACKGROUND

Asthmatic children requiring treatment in the pediatric intensive care unit (PICU) receive aggressive drug therapy that may include IV administration of β 2-receptor agonists to prevent progression to life-threatening respiratory failure. The only pharmacologic agent in this class currently available for parenteral use in the United States is terbutaline. Study of IV dosing of terbutaline in the pediatric population has been limited.

OBJECTIVE

The aim of this study was to determine the pharmacokinetic (PK) properties and tolerability of single-dose terbutaline in pediatric patients across a broad age range who were admitted to the PICU and were receiving maximal conventional asthma drug therapy.

METHODS

This study was conducted at the PICU at Rainbow Babies and Children's Hospital (Cleveland, Ohio). Patients aged 6 months to 16 years with severe exacerbation of reactive airways disease and who were undergoing maximal conventional therapy and had an arterial catheter were enrolled. Patients were arbitrarily assigned to receive a single IV infusion of 1 of 3 doses of terbutaline (10, 20, or 30 μg/kg), infused over 5 minutes. Blood samples were obtained for the determination of plasma terbutaline concentrations just before terbutaline was administered (baseline), immediately on completion of the IV infusion, and at 10, 20, and 40 minutes and 1, 2, 4, 8, 16, 32, 48, and 72 hours after the 5-minute infusion. PK properties (elimination half-life [tl2], mean residence time [MRT], apparent steady-state volume of distribution [Vdss], and total body clearance [CI]) were determined and adverse effects were recorded.

RESULTS

The determination of terbutaline PK properties was possible in 50 of 56 enrolled patients (31 boys, 19 girls; mean [SD] age, 6.5 [4.5] years). The PK properties of terbutaline were linear over the dose range studied and, with the exception of the expected dose-dependent increases in peak terbutaline plasma concentration and area under the terbutaline plasma concentration-time curve, no statistically significant differences were observed in PK relative to dose. Therefore, we pooled the data for all subsequent analyses. Statistically significant correlations with patient age were observed with tl2 (r = 0.4, P < 0.006), MRT (r = 0.4, P < 0.002), and Vdss (r = 0.33, P < 0.02), but not C1 (r = -0.03, P = NS). Single-dose terbutaline administration was generally well tolerated.

CONCLUSIONS

Single-dose IV terbutaline was well tolerated in this study. In maximally treated asthmatic patients in the PICU, terbutaline elimination may be more rapid than in nonacutely ill children. These PK data suggest that if the drug is to be administered intravenously, the continuous IV infusion method, including loading doses for any subsequent dose escalations, may be the most appropriate. The influence of age and safety of long-term, continuous terbutaline IV infusion requires further study.

The need for pediatric studies of allergy and asthma medications

For many years, clinicians have accepted the fact that most medications do not have dosing guidelines for children younger than 12 years of age. Recently, there has been a great effort to correct this deficiency. With the introduction of the 1997 Food and Drug Administration Modernization Act, a provision was established to grant additional market exclusivity to pharmaceutical firms that performed the required studies that would lead to improved labeling of medications for children. This effort has resulted in a significant advance for the management of asthma and allergic disorders in children. Several allergy and asthma medications are now approved for use in children as young as 1 year of age, with studies currently being conducted in younger age groups. In this review, we discuss the background for this effort and the continuing impact it will have on the future management of allergy and asthma in children.

Identifying the child in need of asthma therapy

Based on the results of the long-term CAMP clinical trial in childhood asthma, the benefits of continuous long-term use of inhaled glucocorticoid on asthma control are clear. Studies are in progress to evaluate whether early intervention with inhaled glucocorticoids can alter the natural history of asthma. Indicators are now being defined to identify the patient at risk for persistent asthma and thus to identify candidates for early intervention. Given the right medication and the patient profile, it may be possible to induce remission or even a cure. Patients with severe asthma have low pulmonary function that is difficult to improve, however. It will be important to recognize patients at risk for severe asthma and to intervene more effectively to prevent asthma progression. None of these advances will be possible without a comprehensive approach to asthma care including the ready access to health care. Although it seems that the rise in asthma mortality and morbidity has reached a plateau, there are significant racial and ethic disparities in asthma health care use and mortality. The goal should now be to strive for a reduction in asthma morbidity and mortality. A high proportion of asthma morbidity among inner-city children may be related to nonadherence; therefore targeting management approaches to improve adherence could prove effective in reducing morbidity. Recommendations have been made to integrate available resources in the United States to improve overall asthma outcomes for children.

The antiallergic drug oxatomide promotes human eosinophil apoptosis and suppresses IL-5-induced eosinophil survival

BACKGROUND

Eosinophils accumulated in sites of allergic inflammation are thought to play a crucial role in the pathogenesis of allergic disorders including asthma, allergic rhinitis, and atopic dermatitis, and tissue eosinophilia is attributable to increased eosinophil survival or decreased eosinophil apoptosis.

OBJECTIVE

Effects of the antiallergic, histamine H1 blocker oxatomide on viability and apoptosis of eosinophils isolated from the peripheral blood of atopic subjects were studied.

METHODS

Eosinophil viability and apoptosis were evaluated by using a colorimetric assay and annexin V-labeling, caspase-3 activity, and DNA fragmentation assay.

RESULTS

The viability of eosinophils increased in the presence of IL-5 (10 ng/mL), confirming that IL-5 prolongs eosinophil survival in vitro. Application of oxatomide at concentrations over 20 micromol/L for 24 hours decreased the IL-5-induced enhancement of eosinophil viability. Double staining of the cells with annexin V and propidium iodide showed that deprivation of IL-5 promoted spontaneous eosinophil apoptosis and that oxatomide facilitated apoptosis and suppressed the prolongation of eosinophil survival stimulated by IL-5. In the absence of IL-5, approximately 71% and 96% of eosinophils after 24 and 48 hours, respectively, underwent spontaneous apoptosis. IL-5 decreased the rate of eosinophil apoptosis to 38% and 52% after 24 and 48 hours, respectively. Oxatomide increased eosinophil apoptosis in a concentration-dependent manner in the presence of IL-5. Furthermore, oxatomide increased caspase-3 activity and DNA fragmentation.

CONCLUSION

We demonstrated that oxatomide possesses a novel therapeutic effect of apoptosis promotion on eosinophils and prevents the antiapoptotic effects of IL-5, suggesting that oxatomide may contribute to resolution of tissue eosinophilia in allergic inflammation.

Advances in childhood asthma: hygiene hypothesis, natural history, and management

There is significant interest in early identification and intervention in childhood asthma. Current asthma guidelines identify inhaled corticosteroids (ICS) as the preferred initial long-term control therapy even in young children. ICS clearly improve asthma control in children with mild to moderate persistent asthma, but it is not clear that they can alter the natu-ral history and progression of asthma. New insights regarding the origins of asthma and allergy and their natural history will continue to stimulate questions regarding the appropriate time for intervention and will stimulate the design of new treatment strategies and the discovery of new medications.

Update on glucocorticoid action and resistance

Glucocorticoids (GCs) are the most common group of medications used in the treatment of allergic and autoimmune disorders. They produce potent anti-inflammatory effects by inducing or repressing the expression of target genes. Although most patients with allergic diseases and autoimmune disorders respond to GC therapy, a small subset of patients demonstrate persistent tissue inflammation despite treatment with high doses of GCs. This condition results from an interaction between susceptibility genes, the host's environment, and immunologic factors. The treatment of these patients requires a systematic approach to rule out underlying conditions that lead to steroid resistance or treatment failure, as well as the use of alternative strategies to inhibit tissue inflammation.