Use of exhaled nitric oxide measurements to guide treatment in chronic asthma

Small airway inflammation is associated with residual airway hyperresponsiveness in Th2-high asthma

Background: Asthma is characterized by airway inflammation, variable airflow obstruction, and airway hyperresponsiveness (AHR). Generally, AHR takes longer to resolve than does airflow obstruction or clinical symptoms. AHR occasionally persists despite adequate asthma treatment.Objective: To evaluate factors which associates with residual AHR in patients with seemingly remitted airway inflammation.Methods: Patients who exhibited high fractional exhaled nitric oxide (FeNO) levels (>25 ppb) at the first visit (Visit 1) and normalized FeNO levels (<25 ppb) after adequate asthma treatment, including inhaled corticosteroid administration (Visit 2), were analyzed. Patients underwent a blood test, FeNO and small airway/alveolar nitric oxide concentration (CANO) measurements and a methacholine challenge test (continuous inhalation method) at both visits. Clinical indices were compared between patients with and without residual AHR.Results: Fifty patients were analyzed. All exhibited high FeNO levels at Visit 1 [mean, 54.0 ppb (95% confidence interval, 42.4-65.5)] and improvement of FeNO levels at Visit 2 [20.4 (19.2-21.6)] (p < 0.0001). Thirty-three patients (66%) had remission of AHR at Visit 2. No significant differences were observed between patients with and without residual AHR in terms of FeNO levels, lung function parameters and blood eosinophil counts at both visits. CANO level at Visit 2 was the only factor that significantly differed between patients with residual AHR [2.7 (1.9-3.6)] and those who achieved AHR remission [0.8 (0.5-1.0)] (p < 0.0001).Conclusion: Small airway inflammation, as assessed by CANO, was associated with residual AHR in patients with Th2-high asthma.

Exercise capacity reflects airflow limitation rather than hypoxaemia in patients with pulmonary arteriovenous malformations

BACKGROUND

Pulmonary arteriovenous malformations (PAVMs) generate a right-to-left shunt. Impaired gas exchange results in hypoxaemia and impaired CO2 clearance. Most patients compensate effectively but some are dyspneic, and these are rarely the most hypoxaemic.

AIM

To test degrees of concurrent pathology influencing exercise capacity.

DESIGN

Replicate, sequential single centre, prospective studies.

METHODS

Cardiopulmonary exercise tests (CPETs) were performed in 26 patients with PAVMs, including individuals with and without known airflow obstruction. To replicate, relationships were tested prospectively in an independent cohort where self-reported exercise capacity evaluated by the Veterans Specific Activity Questionnaire (VSAQ) was used to calculate metabolic equivalents (METs) at peak exercise (n = 71). Additional measurements included oxygen saturation (SpO2), forced expiratory volume in 1 s (FEV1), vital capacity (VC), fractional exhaled nitric oxide (FeNO), haemoglobin and iron indices.

RESULTS

By CPET, the peak work rate was only minimally associated with low SpO2 or low arterial oxygen content (calculated as CaO2=1.34 × SpO2 × haemoglobin), but was reduced in patients with low FEV1 or VC. Supranormal work rates were seen in patients with severe right-to-left shunting and SpO2 < 90%, but only if FEV1 was >80% predicted. VSAQ-calculated METS also demonstrated little relationship with SpO2, and in crude and CaO2-adjusted regression, were lower in patients with lower FEV1 or VC. Bronchodilation increased airflow even where spirometry was in the normal range: exhaled nitric oxide measurements were normal in 80% of cases, and unrelated to any PAVM-specific variable.

CONCLUSIONS

Exercise capacity is reduced by relatively mild airflow limitation (obstructive or restrictive) in the setting of PAVMs.

Exhaled nitric oxide in chronic cough: A good tool in a multi-step approach

INTRODUCTION

The impact of fractional exhaled nitric oxide (FENO) on the management of chronic cough (CC) is still inconclusive. The aim of the present study was to assess whether FENO is a good tool to predict the response to inhaled corticosteroids (ICS) in patients with CC.

METHODS

Patients, referred for investigation of CC, had a FENO measurement determined as part of their first-line assessment. A methacholine test was performed as part of a second-line assessement. Patients were assigned to two groups according to their FENO values: a high FENO level group (Ⱕ25 ppb) and a normal FENO level group (<25 ppb).

RESULTS

One hundred patients were included in the study. High FENO levels were found in 25 patients (25%). The proportion of patients who responded to ICS was significantly greater in the high FENO group compared to the normal FENO level group (86.4% vs 46.3%, P<0.05). FENO is a good tool to predict ICS response in patients with high FENO levels but a response to ICS cannot be ruled out in patients with normal FENO levels. In patients with normal FENO values, a methacholine test could be an interesting tool for a second-line assessment. Among the 13 patients with a positive methacholine test result, 11 responded to ICS whilst 2 did not. Of the patients with a negative methacholine test result, 3 responded to ICS whilst 13 did not.

CONCLUSION

FENO may be a more reliable predictor of ICS response when used as part of a multi-step assessment procedure.

Biomarkers and asthma management: analysis and potential applications

PURPOSE OF REVIEW

Asthma features a high degree of heterogeneity in both pathophysiology and therapeutic response, resulting in many asthma patients being treated inadequately. Biomarkers indicative of underlying pathological processes could be used to identify disease subtypes, determine prognosis and to predict or monitor treatment response. However, the newly identified as well as more established biomarkers have different applications and limitations.

RECENT FINDINGS

Conventional markers for type 2-high asthma, such as blood eosinophils, fraction of exhaled nitric oxide, serum IgE and periostin, feature limited sensitivity and specificity despite their significant correlations. More distinctive models have been developed by combining biomarkers and/or using omics techniques. Recently, a model with a positive predictive value of 100% for identification of type 2-high asthma based on a combination of minimally invasive biomarkers was developed.

SUMMARY

Individualisation of asthma treatment regimens on the basis of biomarkers is necessary to improve asthma control. However, the suboptimal properties of currently available conventional biomarkers limit its clinical utility. Newly identified biomarkers and models based on combinations and/or omics analysis must be validated and standardised before they can be routinely applied in clinical practice. The development of robust biomarkers will allow development of more efficacious precision medicine-based treatment approaches for asthma.

Pharmacodynamic monitoring using biomarkers to individualize pharmacotherapy

Drug doses are often titrated upon their clinical effects (e.g., blood pressure). Unfortunately, for many drugs there is no direct, clinical read-out to estimate dose adequateness. Alternatively, drug dosing is based on the maximum tolerated dose approach or therapeutic drug monitoring. However, the concentration-response curves may be flattened or bell-shaped as suggested for some ‘biologicals’. Together, these aspects raise the question why drug dosing is not individualized by pharmacodynamic monitoring. Evaluating the effects of drugs at their pharmacological target or meaningful biomarkers might indicate nonresponders, objectively quantify the maximum molecular effect and thus restrict overdose and underdosing. This review outlines the theory and biological or technical prerequisites for biomarker-based pharmacodynamic monitoring, and highlights selected examples from different fields of clinical medicine.

The Fraction Exhaled Nitric Oxide as a Biomarker of Asthma Control

INTRODUCTION AND OBJECTIVE

The main goal of asthma treatment is to achieve and maintain clinical control of the disease. The exhaled fraction nitric oxide (FeNO) level is a biomarker of T-helper cell type 2 (Th2) inflammation of the airways. Our objective was to determine whether the FeNO level can be used to discriminate between patients with controlled, partially controlled, and uncontrolled asthma.

MATERIALS AND METHODS

The FeNO level and asthma control were evaluated in a retrospective and analytic cross-sectional study through data collected from asthmatic patients who were assessed by clinical history, asthma control, physical examination, spirometry, and FeNO level. Asthma control was determined by the criteria of the Global Initiative for Asthma and classified as controlled asthma, partially controlled asthma, and uncontrolled asthma. The FeNO values were classified as low (<25 ppb) or intermediate/high (⩾25 ppb) based on the American Thoracic Society recommendations.

RESULTS

The symptoms of 81 asthmatic patients were classified as controlled (34 [42%] patients), partially controlled (27 [33.3%] patients), and uncontrolled (20 [24.7%] patients). The FeNO level discriminated between the uncontrolled and controlled groups (P = .01) and between the uncontrolled and partially controlled groups (P = .01), but not between the controlled and partially controlled groups (P = .98). An FeNO level >30 ppb was associated with uncontrolled asthma (P = .0001) with an area under the receiver operating characteristic curve of 0.78 (95% confidence interval = 0.65-0.89).

CONCLUSIONS

FeNO level could be helpful in determining asthma control as >30 ppb was associated with uncontrolled asthma.

School-aged asthma children with high fractional exhaled nitric oxide levels and lung dysfunction are at high risk of prolonged lung dysfunction

Background

Long-term management of bronchial asthma based on the fractional exhaled nitric oxide (FeNO) value alone is not conclusive yet. Therefore, we combined FeNO testing and spirometry, a commonly used test in routine practice, to evaluate acute exacerbation and respiratory function in children with bronchial asthma.

Objective

We combined FeNO testing and spirometry, commonly used in routine practice, to evaluate acute exacerbations and respiratory function in children with bronchial asthma.

Methods

Subjects were school aged children 7 years and older with bronchial asthma who underwent FeNO testing in January 2015 to May 2016. We evaluated the changes in the frequency of acute exacerbations and respiratory function in the 30 subsequent months. Subjects were divided into 2 groups: those with initial FeNO levels ≥ 21 parts per billion (ppb) (high FeNO) and < 20 ppb (normal FeNO) groups.

Results

There were 48 children (33 boys) in the high FeNO group and 68 children (46 boys) in the normal FeNO group. Spirometry was conducted on 83 children (72%) prior to the initial FeNO test, revealing no difference in the ratio of detecting lung dysfunction between the 2 groups. The observation period was 25.8 ± 0.7 and 24.7 ± 0.6 months for the high and normal FeNO groups, respectively. The children in the high FeNO group with lung dysfunction in the initial FeNO test continued to exhibit lung dysfunction at the test at 30 months. In the normal FeNO group, even if lung dysfunction was observed at the initial FeNO, it improved within the 20-month point, and the improvement was maintained thereafter.

Conclusion

Children with bronchial asthma with high FeNO levels and lung dysfunction are at a higher risk of prolonged lung dysfunction.

Fractional Exhaled Nitric Oxide-Assisted Management of Uncontrolled Persistent Asthma: A Real-World Prospective Observational Study

CONTEXT

The utility of fractional exhaled nitric oxide (FeNO) measurement in real-world asthma management requires investigation.

OBJECTIVE

To determine whether FeNO-assisted care added to standard asthma management improves asthma control in a managed care organization.

DESIGN

Prospective observational study in patients aged 12 years and older with uncontrolled persistent asthma identified during a scheduled visit to an Allergy Department that routinely used FeNO (FeNO-assisted care, n = 426) vs visits to 4 Allergy Departments that did not, but followed routine guideline-based care (standard care, n = 925). The FeNO-assisted care was based on FeNO level, asthma control status, and step-care level.

MAIN OUTCOME MEASURES

Composite primary outcome was 1 or more asthma exacerbations or 7 or more dispensed canisters containing short-acting β2-agonists in the follow-up year. Inverse probability of treatment weighting propensity scoring balanced covariates, and multivariable regression analyses compared outcomes between groups.

RESULTS

Compared with standard care, FeNO-assisted care was not associated with reducing the primary composite outcome (adjusted risk ratio = 0.94, 95% confidence interval = 0.69-1.29, p = 0.71), nor with a reduction in asthma exacerbations or dispensing of 7 or more short-acting β2-agonist canisters as separate outcomes. In an atopic subgroup with aeroallergen sensitization, the composite outcome was similar between groups, but the rate of asthma exacerbations was lower with FeNO-assisted treatment (adjusted rate ratio = 0.67, 95% confidence interval = 0.49-0.91, p = 0.01).

CONCLUSION

These findings suggest future studies of FeNO-assisted care should be directed at the atopic phenotype.

Measurement of fractional exhaled nitric oxide in real-world clinical practice alters asthma treatment decisions

BACKGROUND

Assessment of asthma using clinical measures alone often fails to detect underlying airway inflammation. Fractional exhaled nitric oxide (FeNO) is a recognized biomarker of type 2 airway inflammation in asthma. Measurement of FeNO is instrumental in the assessment and management of patients with corticosteroid-sensitive asthma.

OBJECTIVE

To determine the impact of measuring FeNO on asthma management in real-world clinical practices.

METHODS

Clinicians from 337 US practices performed a clinical assessment and recorded treatment plans before and after measuring FeNO in 7,901 patients with asthma. Airway inflammation was classified as low, intermediate, or high according to the clinician's usual procedures, including clinical examination, spirometry, and symptoms. Clinicians recorded asthma medication plans, indicating medications to be initiated, continued, or stopped. FeNO measurement was performed, followed by documentation of any change(s) in the treatment plans based on the FeNO value (eg, initiating new medications or changing the dose of or discontinuing existing medications).

RESULTS

Clinical assessment was concordant with FeNO measurement in only 56% of cases, matching FeNO more frequently in patients with low inflammation (64%) vs high inflammation (34%). After FeNO measurement, clinicians modified their treatment plan in 31% and altered prescriptions for inhaled corticosteroids in 90% of cases. Inhaled corticosteroids were initiated or their dose increased in 66% of patients with high inflammation but discontinued or their dose decreased in only 9% of patients with low inflammation.

CONCLUSION

Measurement of FeNO enabled clinicians to assess underlying airway inflammation, leading to a significant revision of their treatment plans compared with real-world clinical assessment of asthma alone.

Values of fractional exhaled nitric oxide for cough-variant asthma in children with chronic cough

BACKGROUND

Chronic cough is a common symptom in children. We wished to explore the value of fractional exhaled nitric oxide (FeNO) for cough-variant asthma (CVA) in children with chronic cough.

METHODS

This prospective cohort study was conducted in the Children's Hospital of Soochow University from January 2012 to December 2014. Children aged 6-14 years with a cough of duration >4 weeks were enrolled. They underwent FeNO measurement, sputum cytology and pulmonary function tests.

RESULTS

A total of 115 patients and 25 healthy controls were evaluated. For the diagnosis of CVA, the optimal FeNO cutoff value was 25 ppb with a sensitivity of 84.0%, specificity of 97.1%, positive predictive value of 97.5%, and negative predictive of being 81.4%. The FeNO level had a significant correlation with eosinophil count in sputum (P<0.05). FeNO level in CVA was decreased significantly after treatment (P=0.001).

CONCLUSIONS

In children, FeNO measurement might be an excellent method for diagnosing CVA with high sensitivity and specificity.

Urinary organic acids as biomarkers in the assessment of pulmonary function in children with asthma

Childhood asthma prevalence continues to rise despite advancements in prevention and medical management strategies. The purpose of this study was to investigate correlations between urinary organic acids and pulmonary diagnostic tests, asthma control in Greek asthmatic children. We hypothesized that urinary organic acids are positively associated with poor pulmonary function in children with asthma. Seventy-two children, 5 to 12 years old with asthma were recruited from a pediatric asthma clinic in Athens, Greece. Pulmonary function was assessed using spirometry and exhaled nitric oxide analysis. Asthma control was measured qualitatively using the Asthma Control Questionnaire. Targeted metabolomic analysis of 34 urinary organic acids in children was conducted by gas chromatography-mass spectrometry. A statistically significant difference between girls and boys was found for asthma control score (P = .02), lactic acid (P = .03), but not for any other organic acids (P > .05). Statistically significant correlations were found between lactic acid and Forced Expiratory Volume in 1 second (FEV₁) (P = .02), Forced Vital Capacity (FVC) (P = .03); 4- hydroxyphenylacetic acid and FEV₁ (P = .01), FVC (P = .01); 5-hydroxyindoleacetic acid and FEV₁/FVC (P = .03), eNO (P = .05); glycolic acid with Peak Expiratory Flow (PEF) (P = .03); and malic acid with asthma control (P = .02). In conclusion, metabolomics was used to determine correlations between urinary organic acids and conventional pulmonary diagnostic tests in Greek asthmatic children. Metabolomics could be a promising approach for asthma research and in detection of novel biomarkers for asthma monitoring and therapeutic targets for childhood asthma. This study contributes towards a better understanding of the biochemical pathways involved in asthma.

F eNO-based asthma management results in faster improvement of airway hyperresponsiveness

Asthma is characterised by inflammation and respiratory symptoms. Current asthma treatment is based on severity of asthma symptoms only. Exhaled nitric oxide fraction (F _eNO) is not recommended by the Global Initiative for Asthma guidelines. The aim was to compare the usefulness of a F _eNO guided versus symptom-based treatment in achieving improved asthma control assessed by airway hyperresponsiveness (AHR). 80 asthmatic patients were included in a double-blinded, parallel, randomised controlled trial with follow-up visits after 8, 24 and 36 weeks. Treatment was tailored using either a F _eNO or Asthma Control Questionnaire (ACQ) based algorithm. Inclusion criteria were asthma symptoms and a provocative dose causing a 15% fall in forced expiratory volume in 1 s <635 mg mannitol. At each visit AHR, F _eNO, ACQ and blood tests were performed. No differences between the two groups were found at inclusion. AHR from 8 to 24 weeks was improved in the F _eNO group compared to the ACQ group (response dose ratio (RDR) geometric mean (95% CI): 0.02 (0.01-0.04) versus 0.05 (0.03-0.07), respectively, p=0.015). AHR to mannitol at 36 weeks showed no differences between the two groups (mean difference RDR (95% CI): -0.02 (-0.05-0.02), p=0.3). Total doses of inhaled steroid and number of exacerbations were similar (p>0.05). When using F _eNO as a treatment management tool, lowering of airway responsiveness occurred earlier than using ACQ. However, airway responsiveness and asthma control after 9 months were similar.

Validation of ATS clinical practice guideline cut-points for FeNO in asthma

BACKGROUND

The American Thoracic society (ATS) has suggested using fractional exhaled nitric oxide (FeNO) to monitor the level of eosinophilic (EOS) airway inflammation in asthma, but validation of the proposed cut-points is required in real-life populations.

OBJECTIVE

To validate FeNO cut-points suggested by ATS in relation to sputum EOS count in a real life population of asthma patients.

METHODS

All patients referred consecutively over a 12-months period for specialist assessment of asthma, were examined with FeNO and induced sputum, and re-examined 12 months later. The predicted values of a positive and a negative test (PPV and NPV) for a cut off ≥3% EOS in sputum were calculated. Change in FeNO was defined in accordance with ATS (>20% or 10 ppb if FeNO was <50 ppb).

RESULTS

144 adult asthma patients were examined (59% female). Low FeNO (<25 ppb) at baseline was found in 94 (65%), FeNO between 25 and 50 ppb in 34 (24%) subjects and high FeNO >50 ppb in 16 (11%) subjects. The PPV for FeNO >25 ppb and >50 ppb to predict EOS ≥3% was 45% and 77%, NPV was 88% and 83%. The sensitivity decreased from 70% to 37% at the >50 ppb cut-off. A significant reduction in FeNO was associated with a reduction in sputum EOS (p = 0.01).

CONCLUSION

The findings support the validity of the FeNO cut-points suggested by ATS to monitor eosinophilic airway inflammation in asthma. However, in this real-life population, a large proportion of patients had intermediate FeNO values, which may limit the clinical usefulness of the ATS FeNO cut-points.

Exhaled Nitric Oxide: An Update

Fractional concentration of exhaled nitric oxide (FENO) is a biomarker used to identify allergic airway inflammation. Because it is noninvasive and easy to obtain, its utility has been studied in the diagnosis and management of several respiratory diseases. Much of the research has been done in asthma, and many studies support the use of FENO in aiding diagnosing asthma, predicting steroid responsiveness, and preventing exacerbations by guiding medication dosage and assessing adherence.

Molecular Endotypes Contribute to the Heterogeneity of Asthma

Diagnosis and management of asthma is commonly implemented based on clinical assessment. Although these nonmolecular biomarkers have been useful, limited resolution of the heterogeneity among asthmatic patients and little information regarding the underlying pathobiology of disease in individuals have been provided. Molecular endotying using global transcriptome expression profiling associated with clinical features of asthma has improved our understanding of disease mechanisms, risk assessment of asthma exacerbations, and treatment responses, especially in patients with type 2 inflammation. Further advances in establishing pathobiological subgroups, bioactive pathways, and true disease endotypes hold potential for a more personalized medical approach in asthmatic patients.

Use of biomarkers to identify phenotypes and endotypes of severeasthma

OBJECTIVE

Severe asthma can be classified into phenotypes and endotypes, which may inform clinicians about inflammatory pathways leading to disease and ultimately guide optimal therapeutic strategy. Biomarkers, objectively measurable characteristics of the disease, are of increasing interest to clinicians and researchers as powerful tools to distinguish among the severe asthma phenotypes and endotypes. The objective of this review is to highlight current knowledge of biomarker applications to identify phenotypes and endotypes of severe asthma.

DATA SOURCES

Sources used include observational cohorts, clinical trials, translational studies, comprehensive reviews, and expert/taskforce statements.

STUDY SELECTIONS

Included studies were selected for their relevance to the topic and for strength of data or study design.

RESULTS

In severe asthma, biomarkers can be used for diagnosis of phenotype or endotype, can also be predictive of clinical outcomes or response to therapy, and may be dynamic with time or therapy. Fully determining phenotype or endotype of severe asthma will require interpretation of combinations of commercially available biomarkers.

CONCLUSION

Biomarkers have multiple potential clinical applications in severe asthma. Novel biomarkers may add accuracy to this field.

Tailoring asthma treatment on eosinophilic markers (exhaled nitric oxide or sputum eosinophils): a systematic review and meta-analysis

BACKGROUND

Asthma guidelines guide health practitioners to adjust treatments to the minimum level required for asthma control. As many people with asthma have an eosinophilic endotype, tailoring asthma medications based on airway eosinophilic levels (sputum eosinophils or exhaled nitric oxide, FeNO) may improve asthma outcomes.

OBJECTIVE

To synthesise the evidence from our updated Cochrane systematic reviews, for tailoring asthma medication based on eosinophilic inflammatory markers (sputum analysis and FeNO) for improving asthma-related outcomes in children and adults.

DATA SOURCES

Cochrane reviews with standardised searches up to February 2017.

STUDY SELECTION

The Cochrane reviews included randomised controlled comparisons of tailoring asthma medications based on sputum analysis or FeNO compared with controls (primarily clinical symptoms and/or spirometry/peak flow).

RESULTS

The 16 included studies of FeNO-based management (seven in adults) and 6 of sputum-based management (five in adults) were clinically heterogeneous. On follow-up, participants randomised to the sputum eosinophils strategy (compared with controls) were significantly less likely to have exacerbations (62 vs 82/100 participants with ≥1 exacerbation; OR 0.36, 95% CI 0.21 to 0.62). For the FeNO strategy, the respective numbers were adults OR 0.60 (95% CI 0.43 to 0.84) and children 0.58 (95% CI 0.45 to 0.75). However, there were no significant group differences for either strategy on daily inhaled corticosteroids dose (at end of study), asthma control or lung function.

CONCLUSION

Adjusting treatment based on airway eosinophilic markers reduced the likelihood of asthma exacerbations but had no significant impact on asthma control or lung function.

Biomarkers for severe allergic asthma in children: could they be useful to guide disease control and use of omalizumab?

INTRODUCTION

Although symptom controls in asthmatic children can be achieved through compliant use of conventional medication, some children have uncontrolled severe persistent asthma, especially if they are allergic. For these children, omalizumab (approved by the EMA and FDA in children aged > 6 years) could be a therapeutic option. However, response to omalizumab varies from one child to another. Predictive biomarkers of omalizumab effectiveness could be useful to monitor response to treatment. Area covered: The authors searched in the PubMed database for publications related to the use of biomarkers in allergic asthma. Supported by their own experience in phenotyping asthma in children, they analyzed whether these biomarkers could be useful in assessing response to omalizumab. Expert commentary: Th2 inflammation in children with allergic asthma can be assessed by measuring several biomarkers (blood eosinophil, serum ECP or periostin, FeNO). While a single measurement may be insufficient, a combination of biomarkers assessments may improve the follow-up of children treated by omalizumab.

Exhaled nitric oxide as a guiding tool for bronchial asthma: A randomised controlled trial

Background

Evidence regarding the role of non-invasive marker of airway inflammation, fractional exhaled nitric oxide (FeNO) to guide asthma treatment is equivocal. We aimed to evaluate if the use of FeNO to adjust inhaled corticosteroid treatment resulted in reduced daily corticosteroid use and lesser exacerbations.

Methods

100 patients of bronchial asthma in the age group of 12-70 years were randomised to receive inhaled corticosteroids based on either FeNO measurements (n = 50) or as per Global Initiative for Asthma (GINA) guidelines. Follow up was done every 2 months for period of 12 months. Results were compared in terms of mean daily inhaled corticosteroid use and number of exacerbations.

Results

After the follow up period of 12 months, mean daily dose of ICS (SD) required in FeNO group was 267.5 μg (126.29), as opposed to control group in which mean daily dose of steroid was 320.00 μg (138.69). However this observed difference in steroid dose was statistically insignificant (p value = 0.061). The estimated mean (SD) rate of asthma exacerbation experienced in follow up period of 12 months in FeNO group was 0.3 episodes (0.54) per patient per year (95% confidence interval, 0.145-455) and 0.4 episodes (0.61) per patient per year in control group (95% confidence interval, 0.228-572). However this difference in rate of exacerbations between the two study groups was not statistically significant (p = 0.387).

Conclusion

FeNO guided management strategy for asthma did not result in statistically significant reduction in dose of inhaled corticosteroids or number of asthma exacerbations.

Influence of dietary nitrate supplementation on lung function and exercise gas exchange in COPD patients

BACKGROUND

During exercise as pulmonary blood flow rises, pulmonary capillary blood volume increases and gas exchange surface area expands through distention and recruitment. We have previously demonstrated that pulmonary capillary recruitment is limited in COPD patients with poorer exercise tolerance. Hypoxia and endothelial dysfunction lead to pulmonary vascular dysregulation possibly in part related to nitric oxide related pathways.

PURPOSE

To determine if increasing dietary nitrate might influence lung surface area for gas exchange and subsequently impact exercise performance.

METHODS

Subjects had stable, medically treated COPD (n = 25), gave informed consent, filled out the St George Respiratory Questionnaire (SGRQ), had a baseline blood draw for Hgb, performed spirometry, and had exhaled nitric oxide (exNO) measured. Then they performed the intra-breath (IB) technique for lung diffusing capacity for carbon monoxide (DLCO) as well as pulmonary blood flow (Qc). Subsequently they completed a progressive semi-recumbent cycle ergometry test to exhaustion with measures of oxygen saturation (SpO₂) and expired gases along with DLCO and Qc measured during the 1st work load only. Subjects were randomized to nitrate supplement group (beetroot juice) or placebo group (black currant juice) for 8 days and returned for repeat of the above protocol.

RESULTS

Exhaled nitric oxide levels rose >200% in the nitrate group (p < 0.05) with minimal change in placebo group. The SGRQ suggested a small fall in perceived symptom limitation in the nitrate group, but no measure of resting pulmonary function differed post nitrate supplementation. With exercise, there was no influence of nitrate supplementation on peak VO₂ or other measures of respiratory gas exchange. There was a tendency for the exercise DLCO to increase slightly in the nitrate group with a trend towards a rise in the DLCO/Qc relationship (p = 0.08) but not in the placebo group. The only other significant finding was a fall in the exercise blood pressure in the nitrate group, but not placebo group (p < 0.05).

CONCLUSION

Despite evidence of a rise in exhaled nitric oxide levels with nitrate supplementation, there was minimal evidence for improvement in exercise performance or pulmonary gas exchange surface area in a stable medically treated COPD population.

Superior Self-Powered Room-Temperature Chemical Sensing with Light-Activated Inorganic Halides Perovskites

Hybrid halide perovskite is one of the promising light absorber and is intensively investigated for many optoelectronic applications. Here, the first prototype of a self-powered inorganic halides perovskite for chemical gas sensing at room temperature under visible-light irradiation is presented. These devices consist of porous network of CsPbBr₃ (CPB) and can generate an open-circuit voltage of 0.87 V under visible-light irradiation, which can be used to detect various concentrations of O₂ and parts per million concentrations of medically relevant volatile organic compounds such as acetone and ethanol with very quick response and recovery time. It is observed that O₂ gas can passivate the surface trap sites in CPB and the ambipolar charge transport in the perovskite layer results in a distinct sensing mechanism compared with established semiconductors with symmetric electrical response to both oxidizing and reducing gases. The platform of CPB-based gas sensor provides new insights for the emerging area of wearable sensors for personalized and preventive medicine.

Severe Asthma Phenotypes - How Should They Guide Evaluation and Treatment?

Although patients with "severe" asthma tend to be characterized by ongoing symptoms and airway inflammation despite treatment with high doses of inhaled and systemic corticosteroids, there is increasing recognition of marked phenotypic heterogeneity within affected patients. Although "precision medicine" approaches for patients with severe asthma are needed, there are many hurdles that must be overcome in daily practice. The National Heart, Lung and Blood Institute's Severe Asthma Research Program (SARP) has been at the forefront of phenotype discovery in severe asthma for the past decade. SARP, along with other international groups, has described clinical severe asthma phenotypes in both adults and children that can be evaluated in the clinical setting. Although these clinical phenotypes provide a good "starting point" for addressing disease heterogeneity in severe asthma in everyday practice, more efforts are needed to understand how these phenotypes relate to underlying disease mechanisms and pharmacological treatment responses. This review highlights the clinical asthma phenotypes identified to date, their associations with underlying endotypes and potential biomarkers, and remaining knowledge gaps that must be addressed before precision medicine can become a reality for patients with severe asthma.

Exhaled nitric oxide as a potential marker for detecting non-ulcer dyspepsia and peptic ulcer disease

Nitric oxide (NO) plays a key role in the development of peptic ulcer disease (PUD). Conversely, the gastric pathogen Helicobacter pylori colonizes the human stomach and contributes to the development of non-ulcer dyspepsia (NUD) and PUD. However, the underlying relation between molecular NO in exhaled breath and H. pylori-associated NUD and PUD remains largely unknown. Here, we found that the excretion kinetics of NO profiles in exhaled breath are altered markedly in H. pylori-infected NUD and PUD subjects. In our observations, PUD led to considerably higher enrichments of NO in exhaled breath compared to NUD, thus revealing a potential link between exhaled NO and ulcer and non-ulcer complications. Our findings therefore suggest that molecular NO in exhaled breath could be used as a potential biomarker for non-invasive diagnosis and selective differentiation of NUD from PUD. Our observations also highlight that alterations of NO in the gastric environment can play an important role in the pathogenesis of peptic ulcers and thus may provide a new strategy for precise evolution of the actual disease state without the need for endoscopic biopsy, even after the eradication of H. pylori infection.

A Self-Powered Breath Analyzer Based on PANI/PVDF Piezo-Gas-Sensing Arrays for Potential Diagnostics Application

The increasing morbidity of internal diseases poses serious threats to human health and quality of life. Exhaled breath analysis is a noninvasive and convenient diagnostic method to improve the cure rate of patients. In this study, a self-powered breath analyzer based on polyaniline/polyvinylidene fluoride (PANI/PVDF) piezo-gas-sensing arrays has been developed for potential detection of several internal diseases. The device works by converting exhaled breath energy into piezoelectric gas-sensing signals without any external power sources. The five sensing units in the device have different sensitivities to various gas markers with concentrations ranging from 0 to 600 ppm. The working principle can be attributed to the coupling of the in-pipe gas-flow-induced piezoelectric effect of PVDF and gas-sensing properties of PANI electrodes. In addition, the device demonstrates its use as an ethanol analyzer to roughly mimic fatty liver diagnosis. This new approach can be applied to fabricating new exhaled breath analyzers and promoting the development of self-powered systems.

Low Variability in Peak Expiratory Flow Predicts Successful Inhaled Corticosteroid Step-Down in Adults with Asthma

BACKGROUND

The prognosis for patients beyond 1 year after reduction of their inhaled corticosteroid (ICS) dose remains unknown. Predictive factors that can be evaluated before the initiation of asthma treatment or at ICS dose reduction are unknown.

METHODS

We prospectively studied 223 patients in 6 hospitals in the National Hospital Organization of Japan during the 36 months after 50% reduction of their daily ICS dose. All patients recorded their morning and evening peak expiratory flows (PEFs) in their diaries. Lung function, bronchial hyperresponsiveness, fractional nitric oxide levels, number of eosinophils in sputum, and serum IgE levels were measured in most patients. Serum levels of IL-10, IL-33, and thymic stromal lymphopoietin before ICS dose reduction were measured in all patients.

RESULTS

During the 36-month study period, asthma control was retained in 127 (59.6%) of the 213 enrolled patients who underwent ICS dose reduction. Multivariate logistic regression analysis revealed that, at the initiation of dose reduction, the factors most predictive of maintenance of asthma control after ICS dose reduction were a low serum IL-33 level (P < .01), low PEF variability over 1 week (P = .014), childhood onset of asthma (at age <10 years) (P = .03), and high serum IL-10 level (P = .035).

CONCLUSIONS

We demonstrated that low PEF variability over 1 week, high serum IL-10 level, and low serum IL-33 concentration were useful factors for predicting that an adult's asthma will remain in control for months to years after a 50% reduction in the daily ICS dose.

Fractional exhaled nitric oxide and multiple breath nitrogen washout in preschool healthy and asthmatic children

INTRODUCTION

Objectively assessing pulmonary disease is challenging in preschool children with asthma. We evaluated the feasibility of measuring fractional exhaled nitrogen oxide (FeNO) and multiple breath nitrogen washout (N₂MBW) in children. We compared their capacities for discriminating between children with asthma and healthy controls.

METHODS

We measured FeNO and N₂MBW-derived indices of lung clearance (LCI_2.5) and conductive and acinar ventilation heterogeneity (S_cond and S_acin) in 65 preschool children; 35 with physician-diagnosed asthma and 30 healthy. FeNO was measured with a portable device (sampling time, 6 s). We employed data quality control guidelines on N₂MBW. Feasibility was evaluated in a maximum of 8 attempts for both methods. Atopic co-morbidity and first-degree disposition were evaluated with the ISAAC-questionnaire.

RESULTS

FeNO and N₂MBW testing were feasible in 45% and 91% of children, respectively. Feasibility was highly age-dependent. In children under 4 years old, FeNO was not feasible, but N₂MBW was 85% feasible. Children with asthma had significantly elevated S_cond values (median; 95% CI) (0.024; 0.020; 0.029) compared to healthy controls (0.019; 0.016; 0.023), but similar FeNO, LCI_2.5 and S_acinvalues.

CONCLUSION

The feasibility of measuring FeNO was highly age-dependent and not applicable in children under age 4. N₂MBW was feasible in the majority of preschool children. S_cond, but not FeNO, could discriminate between children with asthma and healthy controls.

The clinical role of fractional exhaled nitric oxide in asthma control

BACKGROUND

The potential role and characteristics of fractional exhaled nitric oxide (FeNO) remain unclear in the treatment of asthma.

OBJECTIVE

To explore the clinical role of FeNO in asthmatic treatment.

METHODS

We evaluated whether the mean or change of FeNO levels in the treatment period is associated with other conventional control parameters and predicted some clinical outcomes of asthma. We retrospectively analyzed the mean and percentage change of FeNO levels in the first 5 measurements at our hospital.

RESULTS

The study found a significantly strong correlation between FeNO level at diagnosis and the largest changes of FeNO values from diagnosis. No significant correlations were observed between FeNO levels and other parameters (Asthma Control Test [ACT] score or forced expiratory volume in one second [FEV₁]) in mean and percentage change of values under treatment of asthma; however, significant positive correlations were found between ACT scores and FEV₁. The mean FeNO level revealed a significant negative correlation with an annual change in FEV₁ in individuals with asthma who were followed up for more than 2 years. Both the mean ACT score and percent predicted FEV₁ revealed a significant negative correlation with occasional use of systemic corticosteroids.

CONCLUSION

During conventional treatment of asthma, the largest changes of FeNO values from diagnosis were strongly correlated with FeNO levels at diagnosis. As for the unlikely conventional parameters, no significant associations were observed between FeNO levels and deterioration of asthma during the treatment periods. An elevated mean FeNO level may be a marker of decreased lung function in individuals with asthma.

Perspectives on exhaled nitric oxide

The history of nitric oxide (NO) in the respiratory field dates back to the beginning of the 1990s with the pioneering study by Lars Gustafsson et al describing the presence of endogenous NO in the exhaled breath of human beings. Soon after, independent studies showed that exhaled NO concentrations (F_ENO) is higher in asthmatics than in normal subjects. Not all asthmatics demonstrate a high F_ENO, reflecting the heterogeneity of asthma. High values of F_ENO are associated with over-expression of corticosteroid-sensitive iNOS isoform and allergic/eosinophilic inflammation. A major feature of elevated F_ENO in asthma is the prediction of inhaled corticosteroid (ICS) response, and F_ENO more than 50 ppb in adults is a strong indicator of likely ICS sensitivity. In addition, F_ENO values are elevated in asthma when asthma control deteriorates, identifying patients at risk of exacerbations, and, on the other hand, F_ENO reductions during ICS therapy precede improvement in respiratory symptoms and lung function, suggesting that F_ENO is a sensitive predictor of loss of asthma control. F_ENO also predicts the response to biological therapy (anti-IgE, -IL-5 and -IL-13 antibodies) in severe asthma but, interestingly, F_ENO values fall only after treatment with anti-IL-13 and -IL-4/IL-13 receptor antibodies. The use of F_ENO as a Type-2 inflammatory biomarker, in constellation with other Type-2 markers, could help to determine who might benefit from ICS and biological treatment. It remains to find out more precise cut-off values of F_ENO to identify potential ICS responders in specific phenotypes.

Predictive Biomarkers for Asthma Therapy

PURPOSE OF REVIEW

Asthma is a heterogeneous disease characterized by multiple phenotypes. Treatment of patients with severe disease can be challenging. Predictive biomarkers are measurable characteristics that reflect the underlying pathophysiology of asthma and can identify patients that are likely to respond to a given therapy. This review discusses current knowledge regarding predictive biomarkers in asthma.

RECENT FINDINGS

Recent trials evaluating biologic therapies targeting IgE, IL-5, IL-13, and IL-4 have utilized predictive biomarkers to identify patients who might benefit from treatment. Other work has suggested that using composite biomarkers may offer enhanced predictive capabilities in tailoring asthma therapy. Multiple biomarkers including sputum eosinophil count, blood eosinophil count, fractional concentration of nitric oxide in exhaled breath (FeNO), and serum periostin have been used to identify which patients will respond to targeted asthma medications. Further work is needed to integrate predictive biomarkers into clinical practice.

Baseline Features of the Severe Asthma Research Program (SARP III) Cohort: Differences with Age

BACKGROUND

The effect of age on asthma severity is poorly understood.

OBJECTIVES

The objective of this study was to compare the baseline features of severe and nonsevere asthma in the Severe Asthma Research Program (SARP) III cohort, and examine in cross section the effects of age on those features.

METHODS

SARP III is a National Institutes of Health/National Heart Lung Blood Institute multisite 3-year cohort study conducted to investigate mechanisms of severe asthma. The sample included 188 children (111 severe, 77 nonsevere) and 526 adults (313 severe, 213 nonsevere) characterized for demographic features, symptoms, health care utilization, lung function, and inflammatory markers compared by age and severity.

RESULTS

Compared with children with nonsevere asthma, children with severe asthma had more symptoms and more historical exacerbations, but no difference in body weight, post-bronchodilator lung function, or inflammatory markers. After childhood, and increasing with age, the cohort had a higher proportion of women, less allergen sensitization, and overall fewer blood eosinophils. Enrollment of participants with severe asthma was highest in middle-aged adults, who were older, more obese, with greater airflow limitation and higher blood eosinophils, but less allergen sensitization than adults with nonsevere asthma.

CONCLUSIONS

The phenotypic features of asthma differ by severity and with advancing age. With advancing age, patients with severe asthma are more obese, have greater airflow limitation, less allergen sensitization, and variable type 2 inflammation. Novel mechanisms besides type 2 inflammatory pathways may inform the severe asthma phenotype with advancing age.

Relationship between fraction of exhaled nitric oxide and airway morphology assessed by three-dimensional CT analysis in asthma

Fraction of exhaled nitric oxide (FeNO) provides information about chronic inflammation in asthma. However, its relationship with structural changes in the airways is unknown. We aimed to evaluate the correlation between computer-based airway changes and FeNO in patients with asthma. The wall area (WA) and airway inner luminal area (Ai) of the third- to sixth-generation bronchi were measured using three-dimensional computed tomography in asthmatic patients. Each value was corrected by body surface area (BSA). Relationships between FeNO and WA/BSA and Ai/BSA were evaluated. Forty-one clinically stable patients with asthma were evaluated. FeNO was significantly correlated with WA/BSA of the third-, fourth-, fifth- and sixth-generation bronchi (Spearman correlation coefficient (ρ) = 0.326, p = 0.041; ρ = 0.356, p = 0.025; ρ = 0.496, p = 0.002; and ρ = 0.529, p < 0.001, respectively). The correlation with sixth-generation bronchi was significantly greater than with the third-generation bronchi (p = 0.047). Partial rank correlation analysis indicated FeNO was significantly correlated with WA/BSA of the sixth-generation bronchi, independent from confounding factors of Ai/BSA, age, duration of asthma, dose of inhaled corticosteroid, blood eosinophil percentage, and blood IgE (ρ = 0.360, p = 0.034). In contrast, there was no correlation between FeNO and Ai/BSA. FeNO correlates with bronchial wall thickening in asthma patients. Measurement of FeNO may be useful to detect airway remodeling in asthma.

Tailored interventions based on sputum eosinophils versus clinical symptoms for asthma in children and adults

BACKGROUND

Asthma severity and control can be measured both subjectively and objectively. Sputum analysis for evaluation of percentage of sputum eosinophilia directly measures airway inflammation, and is one method of objectively monitoring asthma. Using sputum analysis to adjust or tailor asthma medications is potentially superior to traditional methods based on symptoms and spirometry.

OBJECTIVES

To evaluate the efficacy of tailoring asthma interventions based on sputum analysis in comparison to traditional methods (usually symptom-based with or without spirometry/peak flow) for asthma-related outcomes in children and adults.

SEARCH METHODS

We searched the Cochrane Airways Group Specialised Register of Trials, the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, Embase, trials' registries, and reference lists of articles. The last search was conducted in February 2017.

SELECTION CRITERIA

All randomised controlled comparisons of adjustment of asthma therapy based on sputum eosinophils compared to traditional methods (primarily clinical symptoms and spirometry/peak flow).

DATA COLLECTION AND ANALYSIS

Results of searches were reviewed against pre-determined criteria for inclusion. In this update, two reviewers selected relevant studies, independently assessed trial quality and extracted the data. We contacted authors for further information when relevant. We analysed data as 'treatment received' and performed sensitivity analyses.

MAIN RESULTS

Three new studies were added in this update, resulting in a total of six included studies (five in adults and one involving children/adolescents). These six studies were clinically and methodologically heterogeneous (use of medications, cut-off for percentage of sputum eosinophils and definition of asthma exacerbation). Of 374 participants randomised, 333 completed the trials. In the meta-analysis, there was a significant reduction in the occurrence of any exacerbations when treatment was based on sputum eosinophil counts, compared to that based on clinical symptoms with or without lung function; pooled odds ratio (OR) was 0.57 (95% confidence interval (CI) 0.38 to 0.86). The risk of having one or more exacerbations over 16 months was 82% in the control arm and 62% (95% CI 49% to 74%) in the sputum strategy arm, resulting in a number needed to treat to benefit (NNTB) of 6 (95% CI 4 to 13).There were also differences between the groups in the rate of exacerbation (any exacerbation per year) and severity of exacerbations defined by requirement for use of oral corticosteroids and hospitalisations: the risk of one or more hospitalisations over 16 months was 24% in controls compared to 8% (95% CI 3% to 21%) in the sputum arm. Data for clinical symptoms, quality of life and spirometry were not significantly different between groups. The mean dose of inhaled corticosteroids per day was also similar in both groups. However sputum induction was not always possible. The included studies did not record any adverse events.One study was not blinded and thus was considered to have a high risk of bias. However, when this study was removed in a sensitivity analysis, the difference between the groups for the primary outcome (exacerbations) remained statistically significant between groups. The GRADE quality of the evidence ranged from moderate (for the outcomes 'Occurrence of any exacerbation' and 'Hospitalisation' ) to low (for the outcome 'Mean dose of inhaled corticosteroids per person per day') due to the inconsistency in defining exacerbations and the small number of hospital admissions.

AUTHORS' CONCLUSIONS

In this updated review, tailoring asthma interventions based on sputum eosinophils is beneficial in reducing the frequency of asthma exacerbations in adults with asthma. Adults with frequent exacerbations and severe asthma may derive the greatest benefit from this additional monitoring test, although we were unable to confirm this through subgroup analysis. There is insufficient data available to assess tailoring asthma medications based on sputum eosinophilia in children.Further robust RCTs need to be undertaken and these should include participants with different underlying asthma severities and endotypes.

Airway calibre variation is a major determinant of exhaled nitric oxide's ability to capture asthma control

Changes in airway calibre have the potential to modify exhaled nitric oxide fraction (F_ENO) values and could hamper how F_ENO captures changes in asthma control. Here, our objective was to assess whether forced expiratory volume in 1 s (FEV₁) variations alter the ability of F_ENO to reflect asthma control.F_ENO, asthma control (Asthma Control Questionnaire (ACQ)) and FEV₁ were measured at least two times in 527 patients during 1819 pairs of visits. Determinants of F_ENO-ACQ discordance probability were evaluated through a logistic regression analysis. The effectiveness of F_ENO at capturing either asthma control worsening or improvement between two visits was then assessed by undertaking a stratified receiver operating characteristic curves analysis.When FEV₁ and F_ENO change in the same direction, the odds of F_ENO-ACQ being discordant are multiplied by 3 (p<0.001). The area under the curve values were 0.765 (95% CI 0.713-0.805) (improvement; p<0.001) and 0.769 (95% 0.706-0.810) (worsening; p<0.001) or 0.590 (95% 0.531-0.653) (improvement; p=0.001) and 0.498 (95% 0.416-0.567) (worsening; p=0.482) when FEV₁ and F_ENO changed in the opposite or same direction, respectively.The manner in which F_ENO and FEV₁ vary concomitantly when asthma control changes determines the ability of F_ENO to capture this change: parallel or opposite changes in FEV₁ and F_ENO either decrease or increase this ability to capture asthma control changes.

A Review of Pulmonary Toxicity of Electronic Cigarettes in the Context of Smoking: A Focus on Inflammation

The use of electronic cigarettes (e-cigs) is increasing rapidly, but their effects on lung toxicity are largely unknown. Smoking is a well-established cause of lung cancer and respiratory disease, in part through inflammation. It is plausible that e-cig use might affect similar inflammatory pathways. E-cigs are used by some smokers as an aid for quitting or smoking reduction, and by never smokers (e.g., adolescents and young adults). The relative effects for impacting disease risk may differ for these groups. Cell culture and experimental animal data indicate that e-cigs have the potential for inducing inflammation, albeit much less than smoking. Human studies show that e-cig use in smokers is associated with substantial reductions in blood or urinary biomarkers of tobacco toxicants when completely switching and somewhat for dual use. However, the extent to which these biomarkers are surrogates for potential lung toxicity remains unclear. The FDA now has regulatory authority over e-cigs and can regulate product and e-liquid design features, such as nicotine content and delivery, voltage, e-liquid formulations, and flavors. All of these factors may impact pulmonary toxicity. This review summarizes current data on pulmonary inflammation related to both smoking and e-cig use, with a focus on human lung biomarkers. Cancer Epidemiol Biomarkers Prev; 26(8); 1175-91. ©2017 AACR.

Biomarkers of Airway Type-2 Inflammation and Integrating Complex Phenotypes to Endotypes in Asthma

PURPOSE OF REVIEW

Over the past decade, the most important advance in the field of asthma has been the widespread recognition that asthma is a heterogeneous disease driven by multiple molecular processes.

RECENT FINDINGS

The most well-established molecular mechanism in asthma is increased airway type-2 inflammation, and consequently, non-invasive biomarkers of increased airway type-2 inflammation, such as blood eosinophil counts or blood periostin levels, have proven important in stratifying asthma patients in clinical trials of type-2 cytokine inhibitors. However, it remains ambiguous how well these non-invasive biomarkers represent airway measures of type-2 inflammation in asthma. As a result, the utility of these biomarkers to assist with asthma management or as research tools to better understand asthma pathogenesis remains unclear. This article reviews primary data assessing biomarkers of airway type-2 inflammation in asthma and describes how the use of biomarkers can advance a precision medicine approach to asthma treatment.

Elevated nitric oxide in recurrent vulvovaginal candidiasis - association with clinical findings

INTRODUCTION

Recurrent vulvovaginal candidiasis is defined as having three to four episodes per year and causes substantial suffering. Little is known about the mechanisms leading to relapses in otherwise healthy women. Nitric oxide is part of the nonspecific host defense and is increased during inflammation. Nitric oxide levels were measured and the expression of inducible nitric oxide synthase was analyzed in the vagina during an acute episode of recurrent vulvovaginal candidiasis and after treatment with fluconazole.

MATERIAL AND METHODS

Twenty-eight women with symptoms of recurrent vulvovaginal candidiasis were enrolled together with 31 healthy controls. Nitric oxide was measured with an air-filled 25-mL silicon catheter balloon incubated in the vagina for five minutes and then analyzed by chemiluminescence technique. Vaginal biopsies were analyzed for the expression of inducible nitric oxide synthase. Symptoms and clinical findings were surveyed using a scoring system. The measurements and biopsies were repeated in patients after six weeks of fluconazole treatment.

RESULTS

Nitric oxide levels were increased during acute infection (median 352 ppb) compared with controls (median 6 ppb), p < 0.0001. The levels decreased after treatment (median 18 ppb) but were still higher than in controls. Increased expression of inducible nitric oxide synthase was observed in the epithelial basal layer in patients before and after treatment compared with controls. Before treatment, there were positive correlations between nitric oxide and symptom (r_s  = 0.644) and examination scores (r_s  = 0.677), p < 0.001.

CONCLUSIONS

Nitric oxide is significantly elevated in patients with recurrent vulvovaginal candidiasis during acute episodes of infection and decreases after antifungal treatment. The results illustrate the pronounced inflammatory response in recurrent vulvovaginal candidiasis correlating to symptoms of pain and discomfort.

Japanese guidelines for adult asthma 2017

Adult bronchial asthma is characterized by chronic airway inflammation, and presents clinically with variable airway narrowing (wheezes and dyspnea) and cough. Long-standing asthma induces airway remodeling, leading to intractable asthma. The number of patients with asthma has increased; however, the number of patients who die of asthma has decreased (1.2 per 100,000 patients in 2015). The goal of asthma treatment is to enable patients with asthma to attain normal pulmonary function and lead a normal life, without any symptoms. A good relationship between physicians and patients is indispensable for appropriate treatment. Long-term management by therapeutic agents and elimination of the causes and risk factors of asthma are fundamental to its treatment. Four steps in pharmacotherapy differentiate between mild and intensive treatments; each step includes an appropriate daily dose of an inhaled corticosteroid, varying from low to high levels. Long-acting β₂-agonists, leukotriene receptor antagonists, sustained-release theophylline, and long-acting muscarinic antagonist are recommended as add-on drugs, while anti-immunoglobulin E antibody and oral steroids are considered for the most severe and persistent asthma related to allergic reactions. Bronchial thermoplasty has recently been developed for severe, persistent asthma, but its long-term efficacy is not known. Inhaled β₂-agonists, aminophylline, corticosteroids, adrenaline, oxygen therapy, and other approaches are used as needed during acute exacerbations, by choosing treatment steps for asthma in accordance with the severity of exacerbations. Allergic rhinitis, eosinophilic chronic rhinosinusitis, eosinophilic otitis, chronic obstructive pulmonary disease, aspirin-induced asthma, and pregnancy are also important issues that need to be considered in asthma therapy.

Can biomarkers help us hit targets in difficult-to-treat asthma?

Biomarkers may be a key foundation for the precision medicine of the future. In this article, we review current knowledge regarding biomarkers in difficult-to-treat asthma and their ability to guide the use of both conventional asthma therapies and novel (targeted) therapies. Biomarkers (as measured by tests including prednisolone and cortisol assays and the fractional exhaled nitric oxide (NO) suppression test) show promise in the assessment and management of non-adherence to inhaled and oral corticosteroids. Multiple markers of type 2 inflammation have been developed, including eosinophils in sputum and blood, exhaled NO, serum IgE and periostin. Although these show potential in guiding the selection of novel interventions for refractory type 2 inflammation in asthma, and in determining if the desired response is being achieved, it is becoming clear that different biomarkers reflect distinct components of the complex type 2 inflammatory pathways. Less progress has been made in identifying biomarkers for use in difficult-to-treat asthma that is not associated with type 2 inflammation. The future is likely to see further biomarker discovery, direct measurements of individual cytokines rather than surrogates of their activity and the increasing use of biomarkers in combination. If the promise of biomarkers is to be fulfilled, they will need to provide useful information that aids clinical decision-making, rather than being 'just another test' for clinicians to order.

MyAirCoach: the use of home-monitoring and mHealth systems to predict deterioration in asthma control and the occurrence of asthma exacerbations; study protocol of an observational study

INTRODUCTION

Asthma is a variable lung condition whereby patients experience periods of controlled and uncontrolled asthma symptoms. Patients who experience prolonged periods of uncontrolled asthma have a higher incidence of exacerbations and increased morbidity and mortality rates. The ability to determine and to predict levels of asthma control and the occurrence of exacerbations is crucial in asthma management. Therefore, we aimed to determine to what extent physiological, behavioural and environmental data, obtained by mobile healthcare (mHealth) and home-monitoring sensors, as well as patient characteristics, can be used to predict episodes of uncontrolled asthma and the onset of asthma exacerbations.

METHODS AND ANALYSIS

In an 1-year observational study, patients will be provided with mHealth and home-monitoring systems to record daily measurements for the first-month (phase I) and weekly measurements during a follow-up period of 11 months (phase II). Our study population consists of 150 patients, aged ≥18 years, with a clinician's diagnosis of asthma, currently on controller medication, with uncontrolled asthma and/or minimally one exacerbation in the past 12 months. They will be enrolled over three participating centres, including Leiden, London and Manchester. Our main outcomes are the association between physiological, behavioural and environmental data and (1) the loss of asthma control and (2) the occurrence of asthma exacerbations.

ETHICS

This study was approved by the Medical Ethics Committee of the Leiden University Medical Center in the Netherlands and by the NHS ethics service in the UK.

TRIAL REGISTRATION NUMBER

NCT02774772.

New Insights in Oxidant Biology in Asthma

Research over the past 30 years has identified mechanistic biochemical oxidation pathways that contribute to asthma pathophysiology. Redox imbalance is present in asthma and strongly linked to the pathobiology of airflow obstruction, airway hyperreactivity, and remodeling. High levels of reactive oxygen species, reactive nitrogen species, and oxidatively modified proteins in the lung, blood, and urine provide conclusive evidence for pathologic oxidation in asthma. Concurrent loss of antioxidants, such as superoxide dismutases and catalase, is attributed to redox modifications of the enzymes, and further amplifies the oxidative injury in the airway. The presence of high levels of urine bromotyrosine, an oxidation product of eosinophil peroxidase, identifies activated eosinophils, and shows promise for use as a noninvasive biomarker of poor asthma control.

Inhaled corticosteroid dose response in asthma: Should we measure inflammation?

BACKGROUND

Inhaled corticosteroid (ICS) titration in asthma is primarily based on symptoms and pulmonary function. ICSs may not be increased on this basis despite residual airway inflammation.

OBJECTIVE

To compare the dose-response relationships of ICSs on measures of pulmonary function, symptoms, and inflammation in patients with persistent asthma.

METHODS

We performed a pooled post hoc analysis of 121 patients with mild to moderate asthma from 4 randomized clinical trials that incorporated an ICS dose ramp. Dose ramps were 0 to 200, 0 to 800, and 200 to 800 μg/d (beclomethasone equivalents). Outcome measures included spirometry, fractional exhaled nitric oxide, airway hyperresponsiveness (AHR), symptoms, serum eosinophilic cationic protein, and blood eosinophils.

RESULTS

We found a plateau beyond a small improvement at 0 to 200 μg for forced expiratory volume in 1 second: 3.3% (95% confidence interval [CI], 2.0%-4.7%) at 0 to 200 μg vs 0.3% (95% CI, -0.8% to 1.4%) 200 to 800 μg (P = .001). A similar plateau was seen for symptom improvement beyond 0 to 200 μg. Inflammatory and AHR outcomes revealed further room for improvement beyond low-dose ICSs. There was dose-related suppression (P < .001) for fractional exhaled nitric oxide: 40.4 ppb (95% CI, 34.7-46.9 ppb) for ICS free, 26.8 ppb (95% CI, 23.4-30.2 ppb) for 200 μg, and 20.8 ppb (95% CI, 18.8-23.1 ppb) for 800 μg. Eosinophilic cationic protein concentration was significantly reduced with both higher dose ramps. Eosinophil counts also improved across all 3 dose ramps, with dose separation of 370/μL (95% CI, 280-450/μL) for ICS free vs 250/μL (95% CI, 200-300/μL) 800 μg (P = .03). AHR improved with all 3 dose ramps, with greater improvement at lower doses for indirect vs direct challenges.

CONCLUSION

ICS dose response may extend beyond low dose for inflammation and AHR but not symptoms or spirometry. Further study is required to identify whether this correlates with suboptimal longitudinal asthma control.

TRIAL REGISTRATION

ClinicalTrials.gov Identifiers: NCT00667992, NCT00995657, NCT01216579, NCT01544634.

Pharmacogenomics and Molecular Diagnostics

To develop new Polymerase Chain Reaction (PCR)-based assays for nucleic acid detection for infectious diseases. Development of new assays on demand for emerging infectious diseases. For example, no proper nucleic acid-based tests exist for detection of H1N1 influenza virus. My lab, being the parasitology research unit aims to fill this gap by developing this ability.