Korean allergology has made great progress in keeping pace with global scientific advances in spite of a short history. Outstanding academic and scientific researches have been performed in a variety of allergy fields in Korea. Epidemiologic studies revealed increasing prevalence of asthma and allergic diseases and considerable morbidity and mortality in Korea. Novel inhalant allergens such as citrus red mite and two-spotted spider mite as causes of asthma and allergic rhinitis have been discovered and reported in Korea. Bidirectional translational researches have been performed and are underway to elucidate the pathogenesis of asthma and allergy, mechanisms of airway inflammation and remodeling, and new therapeutic modalities for asthma and allergic diseases. Experimental asthma models of different phenotypes according to exposed levels of lipopolysaccharide or double-stranded RNA suggested the crucial role of the innate immunity in the development of allergic airway inflammation and a new insight for asthma pathogenesis, in which both Th1 and Th2 inflammation are involved. In the field of genetic researches, numerous genetic associations with asthma and asthma-related phenotypes, such as atopy, IgE production, and airway hyperresponsiveness, have been demonstrated in Korean population. The Easy Asthma Management (EAM) program, a computer-assisted asthma management program, is anticipated to facilitate the achievement of more successful clinical outcomes by filling the gaps between guidelines and actual practices. The Integration of these multi-disciplinary allergy research resources and translation of scientific achievements to the bedside and society will lead to better allergy and asthma control in Korea.
Allergy; asthma; Korea
The complex phenotype of allergic bronchial asthma involves a variable degree of bronchoobstruction, increased mucus production, and airway remodeling. So far it is suggested that it arises from multiple interactions of infiltrating and structural cells in the context of chronic airway inflammation that is orchestrated by T helper 2 (TH2) cells. By secreting a plethora of typical mediators such as interleukin (IL) 4, IL-5, and IL-13, these cells hold a key position in asthma pathogenesis. However, therapeutic approaches targeting these TH2-type mediators failed to improve asthma symptoms and impressively showed that asthma pathogenesis cannot be reduced by TH2 cell functions. Recently, other T helper cells, that is, TH9 and TH17 cells, have been identified and these cells also contribute to asthma pathogenesis, the processes leading to formation or aggravation of asthma. Furthermore, TH25 cells, TH3 cells, and regulatory T cells have also been implicated in asthma pathogenesis. This paper aims at summarizing recent insights about these new T helper cells in asthma pathogenesis.
Asthmatics with a severe form of the disease are frequently refractory to standard medications such as inhaled corticosteroids, underlining the need for new treatments to prevent the occurrence of potentially life-threatening episodes. A major obstacle in the development of new treatments for severe asthma is the heterogeneous pathogenesis of the disease, which involves multiple mechanisms and cell types. Furthermore, new therapies might need to be targeted to subgroups of patients whose disease pathogenesis is mediated by a specific pathway. One approach to solving the challenge of developing new treatments for severe asthma is to use experimental mouse models of asthma to address clinically relevant questions regarding disease pathogenesis. The mechanistic insights gained from mouse studies can be translated back to the clinic as potential treatment approaches that require evaluation in clinical trials to validate their effectiveness and safety in human subjects. Here, we will review how mouse models have advanced our understanding of severe asthma pathogenesis. Mouse studies have helped us to uncover the underlying inflammatory mechanisms (mediated by multiple immune cell types that produce Th1, Th2 or Th17 cytokines) and non-inflammatory pathways, in addition to shedding light on asthma that is associated with obesity or steroid unresponsiveness. We propose that the strategy of using mouse models to address clinically relevant questions remains an attractive and productive research approach for identifying mechanistic pathways that can be developed into novel treatments for severe asthma.
The National Urban Air Toxics Research Center (NUATRC) hosted its first scientific workshop in 1994 that focused on possible relationships between air toxics and asthma. From that meeting came recommendations for future research including a need for more complete individual personal exposure assessments so that determinations of personal exposures to pollutants could be made. In the spring of 2001, NUATRC held a second such workshop to review progress made in this area during the intervening 7 years. Peer-reviewed articles from the workshop are published in this issue of (italic)Environmental Health Perspectives Supplements(/italic). As in 1994, academic, government, and industry scientists participated. Dave Guinnup of the Environmental Protection Agency discussed the nature of air toxics, their definition, and the basis for federal regulation. George Leikauf from the University of Cincinnati reviewed the 1994 workshop and subsequent research in this field. Current research funded by NUATRC that is addressing individual personal exposure was presented by Clifford Weisel (Environmental and Occupational Health Sciences Institute, University of Medicine and Dentistry of New Jersey), Patrick Kinney (Columbia University) and Candis Claiborn (Washington State University). David Corry from Baylor College of Medicine highlighted new insights into asthma pathogenesis while Stephen Redd from the Centers for Disease Control presented an overview of asthma epidemiology as well as the societal costs of the disease. Mary White (Agency for Toxic Substances and Disease Registry) discussed recent epidemiologic investigations by public health agencies into community concerns about asthma and hazardous air pollutants. David Peden (University of North Carolina) reviewed scientific studies into the links between asthma and air toxics as well as criteria air pollutants. In a session on occupational asthma, Lee Petsonk (National Institute for Occupational Safety and Health) discussed risk factors for work-related asthma, whereas Ralph Delfino (University of California, Irvine) addressed limitations of extrapolating from occupational asthma to asthma in the general population. These presentations were followed by panel discussions focusing on future research programs, both for NUATRC and similar research institutions. Recommendations for future research included improved assessments of personal exposure to air toxics as well as research focused on specific hazardous air pollutants. The latter recommendation was based on medical literature that suggests certain pollutants from the list of 188 air toxics are most likely to adversely affect respiratory health.
Se is a potent nutritional antioxidant important for various aspects of human health. Because asthma has been demonstrated to involve increased oxidative stress, levels of Se intake have been hypothesized to play an important role in the pathogenesis of asthma. However, significant associations between Se status and prevalence or severity of asthma have not been consistently demonstrated in human studies. This highlights both the complex etiology of human asthma and the inherent problems with correlative nutritional studies. In this review, the different findings in human studies are discussed along with results from limited intervention studies. Mouse models of asthma have provided more definitive results suggesting that the benefits of Se supplementation may depend on an individual's initial Se status. This likely involves T helper cell differentiation and the mechanistic studies that have provided important insight into the effects of Se levels on immune cell function are summarized. Importantly, the benefits and adverse effects of Se supplementation must both be considered in using this nutritional supplement for treating asthma. With this in mind new approaches are discussed that may provide more safe and effective means for using Se supplementation for asthma or other disorders involving inflammation or immunity.
selenium; selenoproteins; asthma; allergic airway inflammation; oxidative stress; immunity
Asthma is characterized by lung inflammation caused by complex interaction between the immune system and environmental factors such as allergens and inorganic pollutants. Recent research in this field is focused on discovering new biomarkers associated with asthma pathogenesis. This review illustrates updated research associating biomarkers of allergic asthma and their potential use in systems biology of the disease. We focus on biomolecules with altered expression, which may serve as inflammatory, diagnostic and therapeutic biomarkers of asthma discovered in human or experimental asthma model using genomic, proteomic and epigenomic approaches for gene and protein expression profiling. These include high-throughput technologies such as state of the art microarray and proteomics Mass Spectrometry (MS) platforms. Emerging concepts of molecular interactions and pathways may provide new insights in searching potential clinical biomarkers. We summarized certain pathways with significant linkage to asthma pathophysiology by analyzing the compiled biomarkers. Systems approaches with this data can identify the regulating networks, which will eventually identify the key biomarkers to be used for diagnostics and drug discovery.
allergic asthma; biomarker; DAAB; TH-2 cytokines and ROS pathway
Asthma is a chronic inflammatory disorder of the airways causing typical symptoms, and the diagnosis is supported by evidence of airflow obstruction which is variable, reversible or inducible. However, standard assessment of lung function with spirometry does not measure dysfunction in small airways which are < 2 mm in diameter towards the periphery of the lung. These airways make only a small contribution to airway resistance under normal circumstances. Nevertheless, there is mounting evidence that pathology and dysfunction in these small airways are implicated in the pathogenesis and natural history of asthma. Using forced oscillation and the multibreath nitrogen washout techniques, uneven ventilation (ventilation heterogeneity) due to small airways dysfunction has been shown to be an important marker of asthma disease activity, even in the absence of abnormalities in standard spirometric measurements. Recent advances in imaging research, particularly with hyperpolarised gas magnetic resonance imaging, have also given insights into the significance and dynamic nature of ventilation heterogeneity in asthma. The challenge is to integrate these new physiological and imaging insights to further our understanding of asthma and facilitate potential new treatments.
Asthma; Small airways; Forced oscillation technique; Multibreath nitrogen washout; Xenon computed tomography; Hyperpolarised gas lung imaging
Asthma is a complex disease characterized by sex-specific differences in incidence, prevalence and severity, but little is known about the molecular basis of these sex differences. Objective: To investigate the genetic architecture of sex differences in asthma risk, we evaluated i) associations between polymorphisms in the interferon-gamma (IFNG) gene and childhood onset asthma in combined and sex-specific samples, and ii) interactions between polymorphisms and sex on asthma risk.
Main and sex-interaction effects of IFNG genetic diversity on asthma risk and IFN-γ levels were examined in a birth cohort of children at high risk for asthma and allergic diseases. Replication of the genetic association was assessed in an independent sample of asthma cases.
Significant genotype-by-sex interactions on asthma were observed for two IFNG SNPs, rs2069727 and rs2430561, which were in strong linkage disequilibrium with each other. In contrast, none of the ten IFNG SNPs showed significant main effects on asthma. The observed genotype-by-sex interaction on asthma was characterized by non-additivity, i.e. heterozygote boys had the highest risk for asthma, while heterozygote girls had the lowest risk. The interaction effect was robust to other asthma risk factors but was limited to children who experienced wheezing illnesses with viral infections during the first three years of life. Genotype-by-sex interactions were also observed in IFN-γ response to LPS in the first year of life. Finally, the sex interaction effect was replicated in an independent population of childhood asthma cases.
These results provide insight into the genetic basis of sex differences in asthma and highlight the potential importance of interactions among sex, genotype, and environmental factors in asthma pathogenesis.
IFN-γ; asthma; children; sex differences; single nucleotide polymorphism; association study
Rationale: Distinct sets of corticosteroid-unresponsive genes modulate disease severity in asthma.
Objectives: To identify corticosteroid-unresponsive genes that provide new insights into disease pathogenesis and asthma therapeutics.
Methods: Experimental murine asthma was induced by nasal administration of house dust mite for 5 days per week. Dexamethasone and apolipoprotein E (apo E) mimetic peptides were administered via osmotic minipumps.
Measurements and Main Results: Genome-wide expression profiling of the lung transcriptome in a house dust mite–induced model of murine asthma identified increases in apo E mRNA levels that persisted despite corticosteroid treatment. House dust mite–challenged apo E−/− mice displayed enhanced airway hyperreactivity and goblet cell hyperplasia, which could be rescued by administration of an apo E(130–149) mimetic peptide. Administration of the apo E(130–149) mimetic peptide to house dust mite–challenged apo E−/− mice also inhibited eosinophilic airway inflammation, IgE production, and the expression of Th2 and Th17 cytokines. House dust mite–challenged low-density lipoprotein receptor (LDLR) knockout mice displayed a similar phenotype as apo E−/− mice with enhanced airway hyperreactivity, goblet cell hyperplasia, and mucin gene expression, but could not be rescued by the apo E(130–149) mimetic peptide, consistent with a LDLR-dependent mechanism.
Conclusions: These findings for the first time identify an apo E–LDLR pathway as an endogenous negative regulator of airway hyperreactivity and goblet cell hyperplasia in asthma. Furthermore, our results demonstrate that strategies that activate the apo E–LDLR pathway, such as apo E mimetic peptides, might be developed into a novel treatment approach for patients with asthma.
asthma; house dust mite; apolipoprotein E; LDL receptor
Asthma is a disease characterized by chronic airway inflammation, and Th2 cells play a critical role in initiating and sustaining asthmatic inflammation. It has been shown that CD44 expressed on CD4+ T cells plays a critical role in the accumulation of antigen-specific Th2 cells in the development of airway hyperresponsiveness induced by antigen challenge in the airways. The aim of this study was to determine whether there are specific CD44 variant isoforms (CD44v) expressed on lymphocytes from asthmatic patients. We collected whole blood samples from 103 normal subjects, 165 subjects with asthma and 104 with pneumonia. Peripheral blood lymphocyte isolation was performed, and total RNA was extracted from the isolated lymphocytes, using nested PCR for specific CD44v amplification on lymphocytes. Demographic variables were analyzed using linear regression in order to determine whether the expression of CD44v was correlated with these demographic features. The nested PCR results revealed that CD44v5 was expressed by 55.2% of asthma patients, which was significantly higher than levels of expression in the other groups. Lower percentages of individuals in the normal subject group exhibited expression of CD44v5 and CD44v6. The data demonstrated that the percentage of individuals in the pneumonia group expressing CD44v5 was 29.0%, but a higher percentage of these patients expressed CD44v6. CD44v5 expression was positively correlated with IgE levels (p=0.032) in the asthmatic patient group, and CD44v6 was significantly positively correlated with the neutrophil count (p<0.05). CD44v5 was expressed by a higher proportion of asthmatic patients than other subjects and thus may play an important role in the pathogenesis of asthma. These findings may offer a new target for the diagnosis and treatment of asthma and may also provide insights into the mechanisms of asthma development.
asthma; peripheral blood lymphocytes; CD44v5; CD44v6
Asthma is on the rise despite intense, ongoing research underscoring the need for new scientific inquiry. In an effort to provide unbiased insight into disease pathogenesis, we took an approach involving expression profiling of lung tissue from mice with experimental asthma. Employing asthma models induced by different allergens and protocols, we identified 6.5% of the tested genome whose expression was altered in an asthmatic lung. Notably, two phenotypically similar models of experimental asthma were shown to have distinct transcript profiles. Genes related to metabolism of basic amino acids, specifically the cationic amino acid transporter 2, arginase I, and arginase II, were particularly prominent among the asthma signature genes. In situ hybridization demonstrated marked staining of arginase I, predominantly in submucosal inflammatory lesions. Arginase activity was increased in allergen-challenged lungs, as demonstrated by increased enzyme activity, and increased levels of putrescine, a downstream product. Lung arginase activity and mRNA expression were strongly induced by IL-4 and IL-13, and were differentially dependent on signal transducer and activator of transcription 6. Analysis of patients with asthma supported the importance of this pathway in human disease. Based on the ability of arginase to regulate generation of NO, polyamines, and collagen, these results provide a basis for pharmacologically targeting arginine metabolism in allergic disorders.
Rationale: Airway responsiveness is a prognostic marker for asthma symptoms in later life.
Objectives: To evaluate characteristics responsible for persistence of airway responsiveness in children with asthma.
Methods: A total of 1,041 children, initially aged 5–12 years, with mild to moderate persistent asthma enrolled in the Childhood Asthma Management Program (CAMP) were studied prospectively for 8.6 ± 1.8 years with methacholine challenges yearly.
Measurements and Main Results: Least squares geometric mean models were fit to determine effects of sex and age on airway responsiveness (provocative concentration producing 20% decrease in FEV1 [PC20]). Multiple linear regression analysis was performed to determine factors at baseline and over time, which were associated with PC20 at end of follow-up. A total of 7,748 methacholine challenges were analyzed. PC20 increased with age, with boys having greater increase after age 11 years than girls (P < 0.001). The divergence coincided with the mean age for Tanner stage 2. Postpubertal girls had greater airway responsiveness, even after adjustment for FEV1 and other potential confounders. Although multivariable regression analyses noted a variety of factors that influenced airway responsivness in both sexes, a history of hay fever (β= −0.30, P = 0.005), respiratory allergy (β= −0.32, P = 0.006), or recent inhaled corticosteroid usage (β= −0.18, P = 0.02) were associated with decrements in final log PC20 only in girls.
Conclusions: Airway responsiveness (PC20) is more severe in the postpubertal female with asthma than in males. Although there are factors associated with airway responsiveness in both males and females, sex-specific factors may contribute to new insights into asthma pathogenesis.
methacholine; PC20; FEV1; bronchoconstriction
Asthma is the most common chronic disease in childhood, characterized by chronic airway inflammation. There are problems with the diagnosis of asthma in young children since the majority of the children with recurrent asthma-like symptoms is symptom free at 6 years, and does not have asthma. With the conventional diagnostic tools it is not possible to differentiate between preschool children with transient symptoms and children with asthma. The analysis of biomarkers of airway inflammation in exhaled breath is a non-invasive and promising technique to diagnose asthma and monitor inflammation in young children. Moreover, relatively new lung function tests (airway resistance using the interrupter technique) have become available for young children. The primary objective of the ADEM study (Asthma DEtection and Monitoring study), is to develop a non-invasive instrument for an early asthma diagnosis in young children, using exhaled inflammatory markers and early lung function measurements. In addition, aetiological factors, including gene polymorphisms and gene expression profiles, in relation to the development of asthma are studied.
A prospective case-control study is started in 200 children with recurrent respiratory symptoms and 50 control subjects without respiratory symptoms. At 6 years, a definite diagnosis of asthma is made (primary outcome measure) on basis of lung function assessments and current respiratory symptoms ('golden standard'). From inclusion until the definite asthma diagnosis, repeated measurements of lung function tests and inflammatory markers in exhaled breath (condensate), blood and faeces are performed. The study is registered and ethically approved.
This article describes the study protocol of the ADEM study. The new diagnostic techniques applied in this study could make an early diagnosis of asthma possible. An early and reliable asthma diagnosis at 2–3 years will have consequences for the management of the large group of young children with asthma-like symptoms. It will avoid both over-treatment of children with transient wheeze and under-treatment of children with asthma. This might have a beneficial influence on the prognosis of asthma in these young children. Besides, insight into the pathophysiology and aetiology of asthma will be obtained.
This study is registered by clinicaltrials.gov (NCT00422747).
Viral respiratory infections are closely associated with wheezing illnesses and exacerbations of asthma throughout childhood, and yet there are a number of remaining questions pertaining to the specific nature of this relationship. Infection with an expanding list of respiratory viruses is an important cause of acute wheezing in infancy, and viruses are detected in most exacerbations of asthma throughout childhood. Furthermore, infants who develop severe viral respiratory infections are more likely to have asthma later in childhood. There has been progress in understanding the pathogenesis of viral respiratory illnesses, and this has led to new insights into how these processes might differ in asthma. Several host factors, including respiratory allergy and virus-induced interferon responses, modify the risk of virus-induced wheezing. In the absence of effective antiviral therapies, treatment of virus-induced wheezing and exacerbations of asthma can be challenging, and studies evaluating current treatment strategies are reviewed. Understanding the host-pathogen interactions that determine the severity of respiratory illnesses and long-term sequelae is likely to be of great help in identifying at-risk individuals, and in designing new and more effective treatments.
rhinovirus; respiratory syncytial virus; asthma
Viruses are the predominant infectious cause of asthma exacerbations in the developed world. In addition, recent evidence strongly suggests that viral infections may also have a causal role in the development of childhood asthma. In this article, we will briefly describe the general perception of how the link between infections and asthma has changed over the last century, and then focus on very recent developments that have provided new insights into the contribution of viruses to asthma pathogenesis. Highlighted areas include the contribution of severe early life viral infections to asthma inception, genetic determinants of severe viral infections in infancy, the differences in innate and adaptive immune system cytokine responses to viral infection between asthmatic and nonasthmatic subjects, and a potential vaccine strategy to prevent severe early life virally-induced illness.
Eosinophil-associated gastrointestinal disorders (EGIDs), including eosinophilic esophagitis (EE) and eosinophilic gastroenteritis (EG), are a spectrum of increasingly recognized inflammatory diseases characterized by gastrointestinal symptoms and eosinophilic infiltration of the gastrointestinal tract. Significant morbidity is associated with the development of esophageal strictures in some patients. Immune-mediated reactions to food allergens appear to drive the inflammation in a subset of patients, especially those with solitary EE, but dietary interventions remain difficult in EE and are less effective in EG. Despite the increasing incidence of these disorders and their increased recognition by physicians, there are currently no medications that either United States or European Union regulatory agencies have specifically approved for use in EGIDs. This lack of safe and effective therapies for EGIDs is a major obstacle in the care of these patients and underscores the need for new therapeutic approaches. This review briefly discusses the currently available “off label” drug treatments for EGIDs, most notably topical and systemic corticosteroids. Pathogenesis studies of EGIDs suggest possible therapeutic targets, and conversely, clinical trials of mechanistically-targeted therapeutics give insight into disease pathogenesis. Thus, EGID pathogenesis is discussed as an introduction to mechanistically-targeted immunotherapeutics. The two biologic categories that have been used in EGIDs, anti-IgE (omalizumab) and anti-IL-5 (SCH55700/reslizumab and mepolizumab), are discussed. Since there are similarities in the pathogenesis of EGIDs with asthma and atopic dermatitis, biologic therapeutics currently in early trials for asthma management are also briefly discussed as potential therapeutic agents for EGIDs. Given the deficiencies of current therapeutics and the rapidly advancing knowledge of the pathogenesis of these disorders, EGIDs are an ideal model for translating recent advances in understanding immunopathogenesis into mechanistically-based therapeutics. Further understanding of the early events in pathogenesis is also needed to develop preventive and disease-modifying treatments.
Asthma-related health resource use and costs may be influenced by increasing asthma prevalence, changes to asthma management guidelines, and new medications over the last decade. The objective of this work was to analyze direct asthma-related medical costs, and trends in total and per-patient costs of hospitalizations, physician visits, and medications.
A cohort of asthma patients from British Columbia (BC), Canada, was created. Asthma patients were identified using a validated case definition. Costs for hospitalizations, physician visits, and medications were calculated from billing records (in 2008 Canadian dollars). Trends in total and per-patient costs over the study period were analyzed using Generalized Linear Models.
398,235 patients satisfied the asthma case definition (mid-point prevalence 8.0%). Patients consumed $315.9 million (M) in direct asthma-related health resources between 2002 and 2007. Hospitalizations, physician visits, and medication costs accounted for 16.0%, 15.7% and 68.2% of total costs, respectively. Cost of asthma increased from $49.4 M in 2002 to $54.7 M in 2007. Total annual costs attributable to hospitalizations and physician visits decreased (−39.8% and −25.5%, respectively; p<0.001), while medication costs increased (+38.7%; p<0.001).
This population-based analysis shows that the total direct cost of asthma in BC has increased since 2002, mainly due to a rise in asthma prevalence and cost of medication. Combination therapy with inhaled corticosteroids/long-acting beta-agonists has become a significant component of the cost of asthma. Although billing records capture only a fraction of the true burden of asthma, the simultaneous increase in medication costs and reductions in hospitalization and physician visit costs provides valuable insight for policy makers into the shifts in asthma-related resource use.
Many studies have shown the effectiveness of self-management for patients with asthma. In particular, possession and use of a written asthma action plan provided by a doctor has shown to significantly improve patients’ asthma control. Yet, uptake of a written asthma action plan and preventative asthma management is low in the community, especially amongst adults.
A Web-based personally controlled health management system (PCHMS) called Healthy.me will be evaluated in a 2010 CONSORT-compliant 2-group (static websites verse PCHMS) parallel randomized controlled trial (RCT) (allocation ratio 1:1).
The PCHMS integrates an untethered personal health record with consumer care pathways and social forums. After eligibility assessment, a sample of 300 adult patients with moderate persistent asthma will be randomly assigned to one of these arms. After 12 months of using either Healthy.me or information websites (usual care arm), a post-study assessment will be conducted.
The primary outcome measure is possession of or revision of an asthma action plan during the study. Secondary outcome measures include: (1) adherence to the asthma action plan, (2) rate of planned and unplanned visits to healthcare providers for asthma issues, (3) usage patterns of Healthy.me and attrition rates, (4) asthma control and asthma exacerbation scores, and (5) impact of asthma on life and competing demands, and days lost from work.
This RCT will provide insights into whether access to an online PCHMS will improve uptake of a written asthma action plan and preventative asthma actions.
Trial Registration: Australian New Zealand Clinical Trials Registry ACTRN12612000716864; https://www.anzctr.org.au/Trial/Registration/TrialReview.aspx?id=362714 (Archived by WebCite at http://www.webcitation.org/6IYBJGRnW).
asthma management; Internet intervention; personalized health record; personally controlled health management system; eHealth; asthma action plan
Prevalence of asthma and allergy has increased over the past 2–3 decades in Westernized countries. Despite increased understanding of the pathogenesis of asthma and allergic diseases, control of severe asthma is still difficult. Asthma is also associated with high prevalence of anxiety in particular adolescents. There is no effective treatment for food allergy. Food allergy is often associated with severe and recalcitrant eczema. Novel approaches for treatment of asthma and food allergy and comorbid conditions are urgently needed. Traditional Chinese medicine (TCM), used in Asia for centuries, is beginning to play a role in Western health care. There is increasing scientific evidence supporting the use of TCM for asthma treatment.
This review article discusses promising TCM interventions for asthma, food allergy and comorbid conditions and explores their possible mechanisms of action. Since 2005, several controlled clinical studies of “anti-asthma” herbal remedies have been published. Among the herbal medicines, anti-asthma herbal medicine intervention (ASHMI) is the only anti-asthma TCM product that is a US FDA investigational new drug (IND) that has entered clinical trials. Research into ASHMI’s effects and mechanisms of actions in animal models is actively being pursued. Research on TCM herbal medicines for treating food allergy is rare. The herbal intervention, Food Allergy Herbal Formula-2 (FAHF-2) is the only US FDA botanical IND under investigation as a multiple food allergy therapy. Published articles and abstracts, as well as new data generated in preclinical and clinical studies of ASHMI and FAHF-2 are the bases for this review. The effect of TCM therapy on food allergy associated recalcitrant eczema, based on case review, is also included.
Laboratory and clinical studies demonstrate a beneficial effect of ASHMI treatment on asthma. The possible mechanisms underlying the efficacy are multiple. Preclinical studies demonstrated the efficacy and safety of FAHF-2 for treating food allergy in a murine model. A clinical study demonstrated that FAHF-2 is safe, well tolerated, and exhibited beneficial immunomodulatory effects. A clinical report showed that TCM treatment reduced eczema scores and improved quality of life. Herbal interventions, ASHMI and FAHF-2 may be further developed as botanical drugs for treating asthma and food allergy. TCM may also be of benefit for comorbid conditions such as anxiety and recalcitrant eczema. More controlled studies are warranted.
In conclusion, novel approaches for treatment of asthma and food allergy and comorbid conditions such as anxiety and eczema are urgently needed. This article discusses promising interventions for such conditions from traditional Chinese medicine (TCM) and explores their possible mechanisms of action.
Herbal interventions; traditional Chinese medicine; ASHMI; FAHF-2; asthma; food allergy
Asthma represents a profound worldwide public health problem. The most effective anti-asthmatic drugs currently available include inhaled β2-agonists and glucocorticoids and control asthma in about 90-95% of patients. The current asthma therapies are not cures and symptoms return soon after treatment is stopped even after long term therapy. Although glucocorticoids are highly effective in controlling the inflammatory process in asthma, they appear to have little effect on the lower airway remodelling processes that appear to play a role in the pathophysiology of asthma at currently prescribed doses. The development of novel drugs may allow resolution of these changes. In addition, severe glucocorticoid-dependent and resistant asthma presents a great clinical burden and reducing the side-effects of glucocorticoids using novel steroid-sparing agents is needed. Furthermore, the mechanisms involved in the persistence of inflammation are poorly understood and the reasons why some patients have severe life threatening asthma and others have very mild disease are still unknown. Drug development for asthma has been directed at improving currently available drugs and findings new compounds that usually target the Th2-driven airway inflammatory response. Considering the apparently central role of T lymphocytes in the pathogenesis of asthma, drugs targeting disease-inducing Th2 cells are promising therapeutic strategies. However, although animal models of asthma suggest that this is feasible, the translation of these types of studies for the treatment of human asthma remains poor due to the limitations of the models currently used. The myriad of new compounds that are in development directed to modulate Th2 cells recruitment and/or activation will clarify in the near future the relative importance of these cells and their mediators in the complex interactions with the other pro-inflammatory/anti-inflammatory cells and mediators responsible of the different asthmatic phenotypes. Some of these new Th2-oriented strategies may in the future not only control symptoms and modify the natural course of asthma, but also potentially prevent or cure the disease.
A substantial body of evidence suggests an etiologic role of inflammation and oxidative/nitrosative stress in asthma pathogenesis. Fractional concentration of nitric oxide in exhaled air (FeNO) may provide a non-invasive marker of oxidative/nitrosative stress and aspects of airway inflammation. We examined whether children with elevated FeNO are at increased risk for new-onset asthma.
We prospectively followed 2206 asthma-free children (age 7–10 years) who participated in the Children’s Health Study. We measured FeNO and followed these children for three years to ascertain incident asthma cases. Cox proportional hazard models were fitted to examine the association between FeNO and new-onset asthma.
We found that FeNO was associated with increased risk of new-onset asthma. Children with the highest quartile of FeNO had more than a two-fold increased risk of new-onset asthma compared to those with the lowest quartile (hazard ratio: 2.1; 95% confidence interval: 1.3–3.5). This effect did not vary by child’s history of respiratory allergic symptoms. However, the effect of elevated FeNO on new-onset asthma was most apparent among those without a parental history of asthma.
Our results indicate that children with elevated FeNO are at increased risk for new-onset asthma, especially if they have no parental history of asthma.
Incident Asthma; Exhaled Nitric Oxide; Airway Inflammation
Oxidative stress plays an important role in the development of airway inflammation and hyperreactivity in asthma. The identification of oxidative stress markers in bronchoalveolar lavage fluid (BALF) and lung tissue from ovalbumin (OVA) sensitized mice could provide new insight into disease pathogenesis and possible use of antioxidants to alleviate disease severity. We used two-dimensional polyacrylamide gel electrophoresis (2D-PAGE) and liquid chromatography-tandem mass spectrometry (LC-MS/MS) to determine the impact of the thiol antioxidant, N-acetylcysteine (NAC), on protein expression in a murine OVA model. At least six proteins or protein families were found to be significantly increased in BALF from OVA-challenged mice compared to a control group: chitinase 3-like protein 3 (Ym1), chitinase 3-like protein 4 (Ym2), acidic mammalian chitinase (AMCase), pulmonary surfactant-associated protein D (SP-D), resistin-like molecule α (RELMα) or “found in inflammatory 1” (FIZZ1), and haptoglobin α-subunit. A total of 9 proteins were significantly increased in lung tissue from the murine asthma model, including Ym1, Ym2, FIZZ1, and other lung remodeling-related proteins. Western blotting confirmed increased Ym1/Ym2, SP-D, and FIZZ1 expression measured from BAL fluid and lung tissue from OVA-challenged mice. Intraperitoneal NAC administration prior to the final OVA challenge inhibited Ym1/Ym2, SP-D, and FIZZ1 expression in BALF and lung tissue. The oxidative stress proteins, Ym1/Ym2, FIZZ1 and SP-D, could play an important role in the pathogenesis of asthma and may be useful oxidative stress markers.
proteomics; asthma pathogensis; N-acetylcysteine; antioxidant; diesel exhaust particle; oxidative stress
Last year’s Advances in Pediatric Asthma concluded with the following statement “If we can close these [remaining] gaps through better communication, improvements in the health care system and new insights into treatment, we will move closer to better methods to intervene early in the course of the disease and induce clinical remission as quickly as possible in most children”. This year’s summary will focus on recent advances in pediatric asthma that take steps moving forward as reported in Journal of Allergy and Clinical Immunology publications in 2010.
Some of those recent reports show us how to improve asthma management through steps to better understand the natural history of asthma, individualize asthma care, reduce asthma exacerbations, manage inner city asthma, and some potential new ways to use available medications to improve asthma control. It is clear that we have made many significant gains in managing asthma in children but we have a ways to go to prevent asthma exacerbations, alter the natural history of the disease, and to reduce health disparities in asthma care.
Perhaps new directions in personalized medicine and improved health care access and communication will help maintain steady progress in alleviating the burden of this disease in children, especially young children.
asthma; asthma control; asthma impairment; asthma risk; asthma severity; early intervention in asthma; biomarkers; genetics; inhaled corticosteroids; leukotriene receptor antagonists; long-acting β-adrenergic agonists; omalizumab; personalized medicine; therapeutics
Asthma in obese individuals is poorly understood, these patients are often refractory to standard therapy.
To gain insights into the pathogenesis and treatment of asthma in obese individuals by determining how obesity and bariatric surgery affect asthma control, airway hyperresponsiveness and markers of asthmatic inflammation.
A prospective study of (i) asthmatic and non-asthmatic bariatric surgery patients compared at baseline, and (ii) asthmatic patients followed for 12 months after bariatric surgery.
We studied 23 asthmatic and 21 non-asthmatic patients undergoing bariatric surgery. At baseline, asthmatics had lower FEV1 and FVC, and lower levels of lymphocytes in bronchoalveolar lavage.
Following surgery, asthmatic participants experienced significant improvements in asthma control (asthma control score 1.55 to 0.74, p < 0.0001) and asthma quality of life (4.87 to 5.87, p < 0.0001). Airways responsiveness to methacholine improved significantly (PC20 3.9 to 7.28, p = 0.03). There was a statistically significant interaction between IgE status and change in airways responsiveness (p for interaction term = 0.01), improvement in AHR was significantly related to change in BMI in those with normal IgE (p = 0.02, R2 = 0.46). The proportion of lymphocytes in bronchoalveolar lavage and production of cytokines from activated peripheral blood CD4+ T cells increased significantly.
Bariatric surgery improves airway hyperresponsiveness in obese asthmatics with normal serum IgE. Weight loss has dichotomous effects on airway physiology and T cell function typically involved in the pathogenesis of asthma, suggesting that obesity produces a unique phenotype of asthma that will require a distinct therapeutic approach.
Obesity; asthma; bariatric surgery; weight loss; airway hyperreactivity; CD4 T cell
Little is known about the role of most asthma susceptibility genes during human lung development. Genetic determinants for normal lung development are not only important early in life, but also for later lung function.
To investigate the role of expression patterns of well-defined asthma susceptibility genes during human and murine lung development. We hypothesized that genes influencing normal airways development would be over-represented by genes associated with asthma.
Asthma genes were first identified via comprehensive search of the current literature. Next, we analyzed their expression patterns in the developing human lung during the pseudoglandular (gestational age, 7-16 weeks) and canalicular (17-26 weeks) stages of development, and in the complete developing lung time series of 3 mouse strains: A/J, SW, C57BL6.
In total, 96 genes with association to asthma in at least two human populations were identified in the literature. Overall, there was no significant over-representation of the asthma genes among genes differentially expressed during lung development, although trends were seen in the human (Odds ratio, OR 1.22, confidence interval, CI 0.90-1.62) and C57BL6 mouse (OR 1.41, CI 0.92-2.11) data. However, differential expression of some asthma genes was consistent in both developing human and murine lung, e.g. NOD1, EDN1, CCL5, RORA and HLA-G. Among the asthma genes identified in genome wide association studies, ROBO1, RORA, HLA-DQB1, IL2RB and PDE10A were differentially expressed during human lung development.
Our data provide insight about the role of asthma susceptibility genes during lung development and suggest common mechanisms underlying lung morphogenesis and pathogenesis of respiratory diseases.
Asthma; Development; Expression; Genetics; Lung