Biomarkers of therapy responsiveness in asthma: pitfalls and promises

Deciphering Exhaled Aerosol Fingerprints for Early Diagnosis and Personalized Therapeutics of Obstructive Respiratory Diseases in Small Airways

Respiratory diseases often show no apparent symptoms at their early stages and are usually diagnosed when permanent damages have been made to the lungs. A major site of lung pathogenesis is the small airways, which make it highly challenging to detect using current techniques due to the diseases’ location (inaccessibility to biopsy) and size (below normal CT/MRI resolution). In this review, we present a new method for lung disease detection and treatment in small airways based on exhaled aerosols, whose patterns are uniquely related to the health of the lungs. Proof-of-concept studies are first presented in idealized lung geometries. We subsequently describe the recent developments in feature extraction and classification of the exhaled aerosol images to establish the relationship between the images and the underlying airway remodeling. Different feature extraction algorithms (aerosol density, fractal dimension, principal mode analysis, and dynamic mode decomposition) and machine learning approaches (support vector machine, random forest, and convolutional neural network) are elaborated upon. Finally, future studies and frequent questions related to clinical applications of the proposed aerosol breath testing are discussed from the authors’ perspective. The proposed breath testing has clinical advantages over conventional approaches, such as easy-to-perform, non-invasive, providing real-time feedback, and is promising in detecting symptomless lung diseases at early stages.

Leveraging statistical shape modeling in computational respiratory dynamics: Nanomedicine delivery in remodeled airways

BACKGROUND AND OBJECTIVE

Accurate knowledge of the delivered doses to the diseased site in the respiratory tract is crucial to elicit desired therapeutic outcomes. However, such information is still difficult to obtain due to inaccessibility for measurement or visualization, complex network structure, and challenges in reconstructing lung geometries with disease-invoked airway remodeling. This study presents a novel method to simulate the airway remodeling in a mouth-lung geometry extending to G9.

METHODS

Statistical shape modeling was used to extract morphological features from a lung geometry database and four new models (i.e., M1-M4) were generated with parameter-controlled dilated/constricted bronchioles in the left-lower (LL) lung. The variations in airflow and particle deposition due to the airway remodeling were simulated using a well-tested k-ω turbulence model and a Lagrangian tracking approach.

RESULTS

Significant variations in flow partitions between the lower and upper lobes of the left lung, as well as between the left and right lungs. The flow partition into the LL lobe varied by 10-fold between the most dilated and constricted models in this study. Significantly lower doses were also predicted on the surface of the constricted LL bronchioles G4-G9, as well as into the peripheral airways beyond G9. However, the total dosimetry in the mouth-lung geometry (up to G9) exhibited low sensitivity to the LL lobar remodeling. Results in this study suggest that the optimal nanomedicine should be 2-10 nm in diameter if targeted at the constricted bronchioles G4-G9 as in topical inhalation therapy but should be larger than 20 nm if targeted at the alveolar region as in systemic therapy.

CONCLUSIONS

This study highlights the large dose variability from local airway remodeling and the need to consider these variations in the treatment planning for pneumonia and other obstructive respiratory diseases.

Inhalation dosimetry of nasally inhaled respiratory aerosols in the human respiratory tract with locally remodeled conducting lungs

Objective: Respiratory diseases are often accompanied by alterations to airway morphology. However, inhalation dosimetry data in remodeled airways are scarce due to the challenges in reconstructing diseased respiratory morphologies. This study aims to study the airway remodeling effects on the inhalation dosimetry of nasally inhaled nanoparticles in a nose-lung geometry that extends to G9 (ninth generation).Materials and methods: Statistical shape modeling was used to develop four diseased lung models with varying levels of bronchiolar dilation/constriction in the left-lower (LL) lobe (i.e. M1-M4). Respiratory airflow and particle deposition were simulated using a low Reynolds number k-ω turbulence model and a Lagrangian tracking approach.Results: Significant discrepancies were observed in the flow partitions between the left and right lungs, as well as between the lower and upper lobes of the left lung, which changed by 10-fold between the most dilated and constricted models.Much lower doses were predicted on the surface of the constricted LL bronchioles G4-G9, as well as into the peripheral airways beyond G9 of the LL lung. However, the LL lobar remodeling had little effect on the dosimetry in the nasopharynx, as well as on the total dosimetry in the nose-lung geometry (up to G9).Conclusion: It is suggested that airway remodeling may pose a higher viral infection risk to the host by redistributing the inhaled viruses to healthy lung lobes. Airway remodeling effects should also be considered in the treatment planning of inhalation therapies, not only because of the dosimetry variation from altered lung morphology but also its evolution as the disease progresses.

Prospective, Single-Arm, Longitudinal Study of Biomarkers in Real-World Patients with Severe Asthma

BACKGROUND

ARIETTA was a prospective, single-arm, noninterventional, multicenter study in patients with severe asthma.

OBJECTIVE

To examine the predictive and prognostic abilities of type 2 biomarkers for severe asthma outcomes.

METHODS

Adult patients with severe asthma receiving daily inhaled corticosteroids (fluticasone propionate ≥500 μg or equivalent) and ≥1 second controller medication were enrolled. Biomarker, clinical, and safety data were collected over 52 weeks. The primary endpoint was the asthma exacerbation rate over 52 weeks in serum periostin-high (≥50 ng/mL at baseline) versus periostin-low subgroups (<50 ng/mL). Correlations between biomarker levels (periostin, blood eosinophils, IgE, and fractional exhaled nitric oxide [FeNO]) and between central and local laboratory measurements (blood eosinophils and IgE) were assessed. The study was terminated before planned enrollment was completed.

RESULTS

Of 465 patients, 66.5% were female, 13.3% were receiving oral corticosteroids, 42.4% had ≥1 exacerbation in the previous year, 52.0% were periostin-high, and 87.5% had type 2 inflammation (blood eosinophils ≥150 cells/μL and/or FeNO ≥25 ppb and/or positive skin allergen test). Biomarker levels correlated poorly with each other. Central and local laboratory blood eosinophil and IgE measurements generally agreed. No difference was observed in exacerbation rates over 52 weeks between periostin-high and periostin-low patients (rate ratio, 0.93; 95% confidence interval, 0.67-1.28; P = .642). Results suggested higher exacerbation rates in patients with blood eosinophils ≥300 cells/μL and FeNO ≥25 ppb.

CONCLUSIONS

No prognostic value for serum periostin related to exacerbations was detected. Higher blood eosinophils combined with increased FeNO were potentially associated with increased exacerbation rates.

Pediatric Clinical Endpoint and Pharmacodynamic Biomarkers: Limitations and Opportunities

Medical research in children typically lags behind that of adult research in both quantity and quality. The conduct of rigorous clinical trials in children can raise ethical concerns because of children's status as a 'vulnerable' population. Moreover, carrying out studies in pediatrics also requires logistical considerations that rarely occur with adult clinical trials. Due to the relatively smaller number of pediatric studies to support evidence-based medicine, the practice of medicine in children is far more reliant upon expert opinion than in adult medicine. Children are at risk of not receiving the same level of benefits from precision medicine research, which has flourished with new technologies capable of generating large amounts of data quickly at an individual level. Although progress has been made in pediatric pharmacokinetics, which has led to safer and more effective dosing, gaps in knowledge still exists when it comes to characterization of pediatric disease and differences in pharmacodynamic response between children and adults. This review highlights three specific therapeutic areas where biomarker development can enhance precision medicine in children: asthma, type 2 diabetes mellitus, and pain. These 'case studies' are meant to update the reader on biomarkers used currently in the diagnosis and treatment of these conditions, and their shortcomings within a pediatric context. Current research on surrogate endpoints and pharmacodynamic biomarkers in the above therapeutic areas will also be described. These cases highlight the current lack in pediatric specific surrogate endpoints and pharmacodynamic biomarkers, as well as the research presently being conducted to address these deficiencies. We finally briefly highlight other therapeutic areas where further research in pediatric surrogate endpoints and pharmacodynamic biomarkers can be impactful to the care of children.

Asthma and Corticosteroid Responses in Childhood and Adult Asthma

Corticosteroids are the most effective treatment for asthma; inhaled corticosteroids (ICSs) are the first-line treatment for children and adults with persistent symptoms. ICSs are associated with significant improvements in lung function. The anti-inflammatory effects of corticosteroids are mediated by both genomic and nongenomic factors. Variation in the response to corticosteroids has been observed. Patient characteristics, biomarkers, and genetic features may be used to predict response to ICSs. The existence of multiple mechanisms underlying glucocorticoid insensitivity raises the possibility that this might indeed reflect different diseases with a common phenotype.

Revisiting Type 2-high and Type 2-low airway inflammation in asthma: current knowledge and therapeutic implications

Asthma is a complex respiratory disorder characterized by marked heterogeneity in individual patient disease triggers and response to therapy. Several asthma phenotypes have now been identified, each defined by a unique interaction between genetic and environmental factors, including inflammatory, clinical and trigger-related phenotypes. Endotypes further describe the functional or pathophysiologic mechanisms underlying the patient's disease. type 2-driven asthma is an emerging nomenclature for a common subtype of asthma and is characterized by the release of signature cytokines IL-4, IL-5 and IL-13 from cells of both the innate and adaptive immune systems. A number of well-recognized biomarkers have been linked to mechanisms involved in type 2 airway inflammation, including fractional exhaled nitric oxide, serum IgE, periostin, and blood and sputum eosinophils. These type 2 cytokines are targets for pharmaceutical intervention, and a number of therapeutic options are under clinical investigation for the management of patients with uncontrolled severe asthma. Anticipating and understanding the heterogeneity of asthma and subsequent improved characterization of different phenotypes and endotypes must guide the selection of treatment to meet individual patients' needs.

Inflammatory biomarkers for asthma endotyping and consequent personalized therapy

INTRODUCTION

We argue that asthma be considered a syndrome caused by multiple inflammatory pathogenic processes. Bronchial hyperresponsiveness, reversible airflow limitation, and chronic airway inflammation characterize asthma pathophysiology. Personalized Medicine, i.e. a tailored management approach, is appropriate for asthma management and is based on the identification of discrete phenotypes and endotypes. Biomarkers can help define phenotypes and endotypes. Several biomarkers have been described in asthma, but most of them are not commonly available or still need external validation. Areas covered: This review presents useful pragmatic biomarkers available in daily clinical practice for assessing airway inflammation in asthmatic patients. Expert commentary: Eosinophil counts and serum allergen-specific IgE assessments are the most reliable biomarkers. Lung function, mainly concerning FEF_25-75, and nasal cytology may be envisaged as ancillary biomarkers in asthma management. In conclusion, biomarkers have a clinical relevance in asthma in identifying asthma endotypes to direct personalized therapy.

Asthma phenotypes in children and stratified pharmacological treatment regimens

INTRODUCTION

Asthma is the most common inflammatory disease in childhood. The interaction of genetic, environmental and host factors may contribute to the development of childhood asthma and defines its progress, including persistence and severity. Until now, various classifications of childhood asthma phenotypes have been suggested based on patient's age during onset of symptoms, type of inflammatory cells, response to treatment and disease severity. Many efforts have been carried out to identify childhood asthma phenotypes and to clarify which are the risk factors that define asthma prediction and the response to therapy. The identification of asthma phenotypes has not only prognostic but also therapeutic role. However, the classification of asthma phenotypes is complex due to the heterogeneity of the disease. Areas covered: The current childhood asthma phenotypes and the new therapeutic strategies for each phenotype are reviewed. Expert commentary: There are multiple phenotypes in childhood asthma and it is crucial to define them before the initiation of personalized treatment. Both the therapeutic strategy and monitoring should follow the recent guidelines.

High-resolution metabolomics to identify urine biomarkers in corticosteroid-resistant asthmatic children

BACKGROUND

Corticosteroid (CS) treatment has been established as the first anti-inflammatory treatment for adults and children with asthma. However, a subset of patients fails to respond to combined systemic and inhaled CS treatment.

OBJECTIVE

This study was aimed at further understanding CS resistance among children with severe asthma.

METHODS

High-resolution metabolomics was performed on urine samples from CS-respondent (n = 15) and CS-nonrespondent (n = 15) children to determine possible urine biomarkers related to CS resistance. The metabolic phenotypes of CS responders and CS nonresponders were analyzed using bioinformatics including Manhattan plot with false- discovery rate, hierarchical cluster analysis, Kyoto Encyclopedia Genes and Genomes, and Mummichog pathway analysis.

RESULTS

The 2-way hierarchical cluster analysis study determined 30 metabolites showing significantly different levels between CS responders and CS nonresponders. The important metabolites annotated were 3,6-dihydronicotinic acid (126.05 m/z, RT: 106, [M+H]⁺), 3-methoxy-4-hydroxyphenyl(ethylene)glycol (185.05 m/z, RT: 155, [M+H]⁺), 3,4-dihydroxy-phenylalanine (198.07 m/z, RT: 446, [M+H]⁺), γ-glutamylcysteine (236.06 m/z, RT: 528, [M+S(34)+H]⁺), Cys-Gly, (253.06 m/z, RT: 528, [M-NH₃+H]⁺), and reduced Flavin mononucleotide (517.0794 m/z, RT: 533, [M+NaCl]⁺). Tyrosine metabolism, degradation of aromatic compounds, and glutathione metabolism are suggested to be significant pathways relating to CS resistance.

CONCLUSIONS

High-resolution metabolomics is a promising approach in asthma research. Five candidate markers were identified to be related to CS-resistant children with severe asthma. These compounds, upon validation, may contribute further in the understanding of CS resistance among children with severe asthma through the use of urine.

Daily life negative mood and exhaled nitric oxide in asthma

BACKGROUND

Psychosocial stress and negative affect have been linked to asthma exacerbations, but longitudinal studies demonstrating a daily life association between negative affect and airway nitric oxide are missing.

OBJECTIVE

The longitudinal association between negative mood fluctuations, exhaled nitric oxide, and lung function in asthma was examined.

METHODS

Self-assessments of the fraction of exhaled nitric oxide (FeNO), spirometry (forced expiratory volume in the first second, FEV1), negative mood, and daily activities were obtained from 20 patients with asthma for 2 months, resulting in 1108 assessments for the analyses (approximately 55 per patient). Concurrent and prospective associations between FeNO, FEV1, and negative mood were analyzed using mixed effects regression models for longitudinal data.

RESULTS

Negative mood was positively associated with changes in FeNO during the same day, and to a stronger extent when prior day negative mood was included in the prediction. FeNO and negative mood were positively associated with same-day FEV1, with the latter relation being partially mediated by changes in FeNO. Associations between FeNO and FEV1 were stronger in younger patients, with earlier onset of asthma, or with lower asthma control. Findings were not changed when controlling for physical activity, medication, cold symptoms, air pollution, and hours spent outside.

CONCLUSION

Daily life changes of negative mood in asthma are positively associated with FeNO changes and FeNO increases are associated with a mild bronchodilation. These findings indicate that psychological influences need to be considered when using FeNO as indicator of airway inflammation and guide for treatment decisions.

Assessing biomarkers in a real-world severe asthma study (ARIETTA)

The prognostic value of asthma biomarkers in routine clinical practice is not fully understood. ARIETTA (NCT02537691) is an ongoing, prospective, longitudinal, international, multicentre real-world study designed to assess the relationship between asthma biomarkers and disease-related health outcomes. The trial aims to enrol and follow for 52 weeks approximately 1200 severe asthma patients from approximately 160 sites in more than 20 countries. Severe asthmatics, treated with daily inhaled corticosteroid (≥500 μg of fluticasone propionate or equivalent) and at least 1 second controller medication are to be included. In this real-world study, patients will be treated according to the investigator's routine clinical practices and no treatment regimen will be implemented as part of the trial. At baseline and again at 26 and 52 weeks, FEV1, FeNO, serum periostin, blood eosinophil count and serum IgE will be measured. Asthma-related symptom and quality of life questionnaires will be administered at the visits and during telephone interviews at Weeks 13 and 39. Data about medication use, asthma exacerbation data, asthma-related healthcare utilization and events raising safety concerns will also be collected. This study design, unique in both its scope and scale, will address fundamental unanswered questions regarding asthma biomarkers and their interrelationship, as well as predict deviations in the course of asthma in a real-world setting.

Current and future biomarkers in allergic asthma

Diagnosis early in life, sensitization, asthma endotypes, monitoring of disease and treatment progression are key motivations for the exploration of biomarkers for allergic rhinitis and allergic asthma. The number of genes related to allergic rhinitis and allergic asthma increases steadily; however, prognostic genes have not yet entered clinical application. We hypothesize that the combination of multiple genes may generate biomarkers with prognostic potential. The current review attempts to group more than 161 different potential biomarkers involved in respiratory inflammation to pave the way for future classifiers. The potential biomarkers are categorized into either epithelial or infiltrate-derived or mixed origin, epithelial biomarkers. Furthermore, surface markers were grouped into cell-type-specific categories. The current literature provides multiple biomarkers for potential asthma endotypes that are related to T-cell phenotypes such as Th1, Th2, Th9, Th17, Th22 and Tregs and their lead cytokines. Eosinophilic and neutrophilic asthma endotypes are also classified by epithelium-derived CCL-26 and osteopontin, respectively. There are currently about 20 epithelium-derived biomarkers exclusively derived from epithelium, which are likely to innovate biomarker panels as they are easy to sample. This article systematically reviews and categorizes genes and collects current evidence that may promote these biomarkers to become part of allergic rhinitis or allergic asthma classifiers with high prognostic value.

Personalized health care beyond oncology: new indications for immunoassay-based companion diagnostics

Personalized health care (PHC) is an evolving field of medicine aimed at providing the right therapy to the right patient at the right time. This approach often incorporates the use of companion diagnostics (CDx) assays that provide information essential for the safe and effective use of the corresponding drug. In addition to oncology, many other therapy areas, such as cardiovascular, neurological, and infectious and inflammatory diseases, may benefit from PHC, owing to disease complexity and heterogeneity. Furthermore, although most U.S. Food and Drug Administration–approved CDx are based on molecular‐based technologies, immunoassays can provide a significant contribution to the evolution of CDx in patient management. In this review we discuss how the incorporation of biomarker immunoassays into routine diagnostic testing may allow early and definitive detection of Alzheimer's disease and enable population enrichment in clinical trials. In addition, we will describe how biomarker‐based CDx immunoassays have potential utility for stratifying patients with asthma based on their potential response to therapy and for selecting treatment according to phenotypic profile. Continued research into the underlying disease pathology and development of accurate and reliable diagnostic assays may ensure that PHC becomes the future standard for many indications.

Oxidative stress and volatile organic compounds: interplay in pulmonary, cardio-vascular, digestive tract systems and cancer

Oxidative stress (OS) can be defined as an imbalance between antioxidant systems and various pro-oxidants. This loss of balance is closely associated with initiation and development of a wide range of systemic or organ specific diseases.

Exhaled breath of healthy humans contains a large number of volatile organic compounds (VOCs) derived from cellular metabolism, released by microorganisms or taken up from the environment. Qualitative or quantitative changes in their composition are associated with diseases and various pathological conditions, also characterized by increased production of reactive oxygen species (ROS), such as superoxide radical, hydrogen peroxide, hydroxyl anion, peroxinitrite, etc. Several volatile organic compounds such as ethane and pentane are direct end-products of the reaction of ROS with various biological compounds (e.g., lipid peroxidation, DNA or protein damage). Being able to accurately identify ROS-generated VOCs could be of particular importance in devising sensitive tests that can diagnose and follow-up oxidative stress-related diseases.

This review describes current knowledge on the associations between oxidative stress and free radicals and the release of several marker volatile organic compounds in a number of diseases. A special focus will be placed on such VOCs in the cardiovascular pathologies, pulmonary diseases and gastro-intestinal tract affections.

Activation states of blood eosinophils in asthma

Asthma is characterized by airway inflammation rich in eosinophils. Airway eosinophilia is associated with exacerbations and has been suggested to play a role in airway remodelling. Recruitment of eosinophils from the circulation requires that blood eosinophils become activated, leading to their arrest on the endothelium and extravasation. Circulating eosinophils can be envisioned as potentially being in different activation states, including non-activated, pre-activated or 'primed', or fully activated. In addition, the circulation can potentially be deficient of pre-activated or activated eosinophils, because such cells have marginated on activated endothelium or extravasated into the tissue. A number of eosinophil surface proteins, including CD69, L-selectin, intercellular adhesion molecule-1 (ICAM-1, CD54), CD44, P-selectin glycoprotein ligand-1 (PSGL-1, CD162), cytokine receptors, Fc receptors, integrins including αM integrin (CD11b), and activated conformations of Fc receptors and integrins, have been proposed to report cell activation. Variation in eosinophil activation states may be associated with asthma activity. Eosinophil surface proteins proposed to be activation markers, with a particular focus on integrins, and evidence for associations between activation states of blood eosinophils and features of asthma are reviewed here. Partial activation of β1 and β2 integrins on blood eosinophils, reported by monoclonal antibodies (mAbs) N29 and KIM-127, is associated with impaired pulmonary function and airway eosinophilia, respectively, in non-severe asthma. The association with lung function does not occur in severe asthma, presumably due to greater eosinophil extravasation, specifically of activated or pre-activated cells, in severe disease.

Clinical application of exhaled nitric oxide measurements in a korean population

Nitric oxide (NO) is a biologic mediator of various physiologic functions. Recent evidence suggests the clinical utility of fractional exhaled NO (FeNO) as a biomarker for assessing asthma and other respiratory diseases. FeNO methodologies have been recently standardized by international research groups and subsequently validated in several Korean population studies. Normal ranges for FeNO have been reported for various ethnic groups, and the clinical utility has been widely evaluated in asthma and various respiratory diseases. Based on current evidence including most of Korean population data, this position paper aims to introduce the methodological considerations, and provide the guidance for the proper clinical application of FeNO measurements in Korean populations.

Exhaled breath analysis by electronic nose in airways disease. Established issues and key questions

Exhaled air contains many volatile organic compounds (VOCs) that are the result of normal and disease-associated metabolic processes anywhere in the body. Different omics techniques can assess the pattern of these VOCs. One such omics technique suitable for breath analysis is represented by electronic noses (eNoses), providing fingerprints of the exhaled VOCs, called breathprints. Breathprints have been shown to be altered in different disease states, including in asthma and COPD. This review describes the current status on clinical validation and application of breath analysis by electronic noses in the diagnosis and monitoring of chronic airways diseases. Furthermore, important methodological issues including breath sampling, modulating factors and incompatibility between eNoses are raised and discussed. Next steps towards clinical application of electronic noses are provided, including further validation in suspected disease, assessment of the influence of different comorbidities, the value in longitudinal monitoring of patients with asthma and COPD and the possibility to predict treatment responses. Eventually, a Breath Cloud may be constructed, a large database containing disease-specific breathprints. When collaborative efforts are put into optimization of this technique, it can provide a rapid and non-invasive first line diagnostic test.

Serum biomarkers in elderly asthma

OBJECTIVE

Asthma is usually misdiagnosed and under-treated in the elderly population, resulting in complications and increased severity to the patient. In this review, we describe some of the most important serum markers of asthma studied so far, reporting their outcomes and possible prediction of asthma in the elderly population.

METHODS

The PubMed electronic database was used to search for promising serum biomarkers of asthma studied in original articles published in peer-reviewed journals from 2000 to January 2013.

RESULTS

A total of 13 relevant serum biomarkers were selected, including IgE, CRP, high sensitive CRP, IL-6, IL-8, IL-17, TNF-α, neopterin, serum amyloid A, eosinophil cationic protein, leukolysin, YKL-40 and soluble CD86.

CONCLUSIONS

Although the major focus of treatment and research has been on allergic asthma, several forms of the disease are recognized, such as neutrophilic asthma, which is characteristic of older patients. Different phenotypes imply different treatments and so it becomes important to correctly determine which type of asthma the patient is suffering from. Serum markers capable of supporting a diagnosis of asthma are needed in order to counter mistreatment and misdiagnosis with other obstructive airways disease (OAD) in elderly patients. As convenient as serum markers may seem to be, a marker capable of accurately identifying asthma with sufficient specificity is yet to be found.

Clinical utility of asthma biomarkers: from bench to bedside

Asthma is a chronic disease characterized by airway inflammation, bronchial hyperresponsiveness, and recurrent episodes of reversible airway obstruction. The disease is very heterogeneous in onset, course, and response to treatment, and seems to encompass a broad collection of heterogeneous disease subtypes with different underlying pathophysiological mechanisms. There is a strong need for easily interpreted clinical biomarkers to assess the nature and severity of the disease. Currently available biomarkers for clinical practice - for example markers in bronchial lavage, bronchial biopsies, sputum, or fraction of exhaled nitric oxide (FeNO) - are limited due to invasiveness or lack of specificity. The assessment of markers in peripheral blood might be a good alternative to study airway inflammation more specifically, compared to FeNO, and in a less invasive manner, compared to bronchoalveolar lavage, biopsies, or sputum induction. In addition, promising novel biomarkers are discovered in the field of breath metabolomics (eg, volatile organic compounds) and (pharmaco)genomics. Biomarker research in asthma is increasingly shifting from the assessment of the value of single biomarkers to multidimensional approaches in which the clinical value of a combination of various markers is studied. This could eventually lead to the development of a clinically applicable algorithm composed of various markers and clinical features to phenotype asthma and improve diagnosis and asthma management.

Inflammatory phenotypes underlying uncontrolled childhood asthma despite inhaled corticosteroid treatment: rationale and design of the PACMAN2 study

BACKGROUND

The diagnosis of childhood asthma covers a broad spectrum of pathological mechanisms that can lead to similarly presenting clinical symptoms, but may nonetheless require different treatment approaches. Distinct underlying inflammatory patterns are thought to influence responsiveness to standard asthma medication.

METHODS/DESIGN

The purpose of the PACMAN2 study is to identify inflammatory phenotypes that can discriminate uncontrolled childhood asthma from controlled childhood asthma by measures in peripheral blood and exhaled air. PACMAN2 is a nested, case-control follow-up study to the ongoing pharmacy-based "Pharmacogenetics of Asthma medication in Children: Medication with Anti-inflammatory effects" (PACMAN) study. The original PACMAN cohort consists of children aged 4-12 years with reported use of asthma medication. The PACMAN2 study will be conducted within the larger PACMAN cohort, and will focus on detailed phenotyping of a subset of the PACMAN children. The selected participants will be invited to a follow-up visit in a clinical setting at least six months after their baseline visit based on their adherence to usage of inhaled corticosteroids, their asthma symptoms in the past year, and their age (≥ 8 years). During the follow-up visit, current and long-term asthma symptoms, medication use, environmental factors, medication adherence and levels of exhaled nitric oxide will be reassessed. The following measures will also be examined: pulmonary function, exhaled volatile organic compounds, as well as inflammatory markers in peripheral blood and blood plasma. Comparative analysis and cluster-analyses will be used to identify markers that differentiate children with uncontrolled asthma despite their use of inhaled corticosteroids (ICS) (cases) from children whose asthma is controlled by the use of ICS (controls).

DISCUSSION

Asthmatic children with distinct inflammatory phenotypes may respond differently to anti-inflammatory therapy. Therefore, by identifying inflammatory phenotypes in children with the PACMAN2 study, we may greatly impact future personalised treatment strategies, uncover new leads for therapeutic targets and improve the design of future clinical studies in the assessment of the efficacy of novel therapeutics.

Developments in the field of allergy in 2011 through the eyes of Clinical and Experimental Allergy

As in previous years, we felt it would be of value to our readership to summarize the new information provided by the authors who have published in Clinical and Experimental Allergy in 2011 and set this in the context of recent advances in our understanding of the pathogenesis and management of allergic disease in all its many manifestations. In 2011, about 210 articles were published in Clinical and Experimental Allergy including editorials, reviews, opinion articles, guidelines, letters, book reviews and of course at the heart of the journal, papers containing original data. As before, this review is divided into sections based on the way the journal is structured, although this year we have grouped together all the papers dealing with mechanisms of allergic disease, whether they involve patients (clinical mechanisms), pure in vitro studies (basic mechanisms) or animal models (experimental models), as we felt this was a more coherent way to deal with the subject. In the field of asthma and rhinitis, the relationship between airway inflammation and airway dysfunction was of perennial interest to investigators, as were phenotypes and biomarkers. Aspirin hypersensitivity appeared in studies in several papers and there was new interest in asthma in the elderly. The mechanisms involved in allergic disease describe advances in our understanding of T cell responses, the relationship between inflammation and disease, mast cell and basophil activation, steroid resistance and novel therapies. In the section dealing with epidemiology, studies seeking to identify risk factors for allergic disease including vitamin D are prominent, as once again are studies investigating gene-environment interactions. The clinical allergy section focuses on drug allergy, food allergy and immunotherapy. The area of oral immunotherapy for food allergy is well covered and we were grateful to Stephen Durham for guest editing an outstanding special issue on immunotherapy in the centenary year of Leonard Noon's pioneering work. Lastly, in the field of allergens, the interest in component-resolved diagnosis continues to grow and there are also articles describing important novel cultivars and the effect of food processing on the allergenic properties of foods. Another terrific year, full of important and high-quality work,which the journal has been proud to bring to the allergy community.

Psychosocial factors and behavioral medicine interventions in asthma

OBJECTIVE

This review examines the evidence for psychosocial influences in asthma and behavioral medicine approaches to its treatment.

METHOD

We conducted a systematic review of the literature on psychosocial influences and the evidence for behavioral interventions in asthma with a focus on research in the past 10 years and clinical trials. Additional attention was directed at promising new developments in the field.

RESULTS

Psychosocial factors can influence the pathogenesis and pathophysiology of asthma, either directly through autonomic, endocrine, immunological, and central nervous system mechanisms or indirectly through lifestyle factors, health behaviors, illness cognitions, and disease management, including medication adherence and trigger avoidance. The recent decade has witnessed surging interest in behavioral interventions that target the various pathways of influence. Among these, self-management training, breathing training, and exercise or physical activation programs have proved particularly useful, whereas other essential or promising interventions, such as smoking cessation, dietary programs, perception and biofeedback training, and suggestive or expressive psychotherapy, require further, more rigorous evaluation. Given the high comorbidity with anxiety and mood disorders, further evaluation of illness-specific cognitive behavior therapy is of particular importance. Progress has also been made in devising community-based and culturally tailored intervention programs.

CONCLUSION

In concert with an essential medication treatment, behavioral medicine treatment of asthma is moving closer toward an integrated biopsychosocial approach to disease management.

Dawn of ocular gene therapy: implications for molecular diagnosis in retinal disease

Personalized medicine aims to utilize genomic information about patients to tailor treatment. Gene replacement therapy for rare genetic disorders is perhaps the most extreme form of personalized medicine, in that the patients' genome wholly determines their treatment regimen. Gene therapy for retinal disorders is poised to become a clinical reality. The eye is an optimal site for gene therapy due to the relative ease of precise vector delivery, immune system isolation, and availability for monitoring of any potential damage or side effects. Due to these advantages, clinical trials for gene therapy of retinal diseases are currently underway. A necessary precursor to such gene therapies is accurate molecular diagnosis of the mutation(s) underlying disease. In this review, we discuss the application of Next Generation Sequencing (NGS) to obtain such a diagnosis and identify disease causing genes, using retinal disorders as a case study. After reviewing ocular gene therapy, we discuss the application of NGS to the identification of novel Mendelian disease genes. We then compare current, array based mutation detection methods against next NGS-based methods in three retinal diseases: Leber's Congenital Amaurosis, Retinitis Pigmentosa, and Stargardt's disease. We conclude that next-generation sequencing based diagnosis offers several advantages over array based methods, including a higher rate of successful diagnosis and the ability to more deeply and efficiently assay a broad spectrum of mutations. However, the relative difficulty of interpreting sequence results and the development of standardized, reliable bioinformatic tools remain outstanding concerns. In this review, recent advances NGS based molecular diagnoses are discussed, as well as their implications for the development of personalized medicine.

Exhaled NO is a poor marker of asthma control in children with a reported use of asthma medication: a pharmacy-based study

BACKGROUND

A high fraction of nitric oxide in exhaled breath (FeNO) has been suggested to be a marker of ongoing airway inflammation and poorly controlled disease in asthma. The usefulness of FeNO to monitor asthma control is still debated today.

AIM

To assess the validity of FeNO as a marker of asthma control in children with reported use of asthma medication.

METHODS

Fraction of nitric oxide in exhaled breath was measured in 601 children (aged 4-12 yr) with reported use of asthma medication in the past 6 months and in 63 healthy non-asthmatic children (aged 5-12). Asthma control was assessed by the Asthma Control Questionnaire (ACQ). A receiver-operator characteristics (ROC) curve was generated to assess the accuracy of FeNO as a marker for asthma control. Logistic regression analysis was used to study whether clinical, healthcare, medication, and environmental factors are associated with high FeNO levels (>25 ppb).

RESULTS

Fraction of nitric oxide in exhaled breath had a poor accuracy to discriminate well-controlled from not well-controlled asthma [area under the ROC curve: 0.56 (95% CI: 0.52-0.61, p = 0.008)]. In addition, high FeNO (>25 ppb) was associated with lower medication adherence rates (OR: 0.4; 95% CI 0.3-0.6), fewer antibiotic courses in the past year (OR: 0.6; 95% CI: 0.4-0.9), fewer leukotriene antagonists use in the past year (OR: 0.4; 95% CI: 0.2-0.9), and fewer visits to a (pulmonary) pediatrician (OR: 0.6; 95% CI: 0.4-0.9). Children living in a non-urban environment had more often high FeNO levels (OR: 1.7; 95% CI: 1.1-2.6).

CONCLUSION

High FeNO is a poor marker of asthma control in children with reported use of asthma medication. Various other factors, including medication adherence and medication use, are associated with increased FeNO levels.

Exhaled nitric oxide measurement in patients affected by nasal polyposis

OBJECTIVES

Nitric oxide (NO) is produced in the respiratory tract with a major contribution coming from paranasal sinuses and the nose. The pathophysiological role of NO in the airways has been debated. The aims of this study were to measure fraction of exhaled NO (FENO), a validated marker of airway inflammation, in patients affected by nasal polyposis with and without asthma; to assess the importance of FENO measurement in detecting subclinical involvement of lower airways in patients with clinical rhinosinusal symptoms; and to clarify the impact of endoscopic surgical removal of polyps on airway inflammation.

SETTING

The study was conducted at the O.R.L. Clinic and Clinical Pharmacology Unit, University Hospital Agostino Gemelli, Rome, Italy.

STUDY DESIGN

Prospective study.

SUBJECTS AND METHODS

Concentrations of FENO were measured with the NIOX system (Aerocrine, Stockholm, Sweden) by using a single-breath online method, according to the American Thoracic Society guidelines.

RESULTS

Compared with those in healthy subjects (15 [11-19] ppb, n = 15; P < .0001), FENO values were elevated in patients with nasal polyposis (41 [21-77] ppb, n = 43). There was no significant difference in FENO concentrations between asthmatic and nonasthmatic patients with nasal polyposis (P = .73). Concentrations of FENO in patients with nasal polyposis were decreased after surgery (64.2 [30.0-132.7] ppb vs 56.0 [26.4-73.8] ppb, respectively; P = .03).

CONCLUSION

The fraction of exhaled NO is elevated in the inflammatory process involving both the rhinosinusal district and lower airways, supporting the one-airway disease hypothesis.

Platelet activation, P-selectin, and eosinophil β1-integrin activation in asthma

RATIONALE

Eosinophil β1-integrin activation correlates inversely with FEV1 and directly with eosinophil-bound P-selectin in subjects with nonsevere allergic asthma.

OBJECTIVES

Determine the relationships between β1-integrin activation and pulmonary function or eosinophil-bound P-selectin in subjects with asthma of varying severity and discern the source of eosinophil-bound P-selectin.

METHODS

Blood was assayed by flow cytometry for P-selectin and activated β1-integrin on eosinophils and platelets. Plasma was analyzed with ELISA for soluble P-selectin, platelet factor 4, and thrombospondin-1.

MEASUREMENTS AND MAIN RESULTS

Activated β1-integrin correlated with eosinophil-bound P-selectin among all subjects with asthma even though activated β1-integrin was higher in subjects with nonsevere asthma than severe asthma. Activated β1-integrin correlated inversely with FEV1 corrected for FVC only in younger subjects with nonsevere asthma. Paradoxically, platelet surface P-selectin, a platelet activation marker, was low in subjects with severe asthma, whereas plasma platelet factor 4, a second platelet activation marker, was high. Correlations indicated that P-selectin-positive platelets complexed to eosinophils are the major source of the eosinophil-bound P-selectin associated with β1-integrin activation. After whole-lung antigen challenge of subjects with nonsevere asthma, a model of asthma exacerbation known to cause platelet activation, circulating eosinophils bearing P-selectin and activated β1-integrin disappeared.

CONCLUSIONS

The relationship between eosinophil β1-integrin activation and pulmonary function was replicated only for younger subjects with nonsevere asthma. However, we infer that platelet activation and binding of activated platelets to eosinophils followed by P-selectin-mediated eosinophil β1-integrin activation occur in both nonsevere and severe asthma with rapid movement of platelet-eosinophil complexes into the lung in more severe disease.