Nitrites in induced sputum as a simple and cheap non-invasive marker of airway inflammation for asthmatic schoolchildren

Early Prediction of Asthma

The clinical manifestations of asthma in children are highly variable, are associated with different molecular and cellular mechanisms, and are characterized by common symptoms that may diversify in frequency and intensity throughout life. It is a disease that generally begins in the first five years of life, and it is essential to promptly identify patients at high risk of developing asthma by using different prediction models. The aim of this review regarding the early prediction of asthma is to summarize predictive factors for the course of asthma, including lung function, allergic comorbidity, and relevant data from the patient's medical history, among other factors. This review also highlights the epigenetic factors that are involved, such as DNA methylation and asthma risk, microRNA expression, and histone modification. The different tools that have been developed in recent years for use in asthma prediction, including machine learning approaches, are presented and compared. In this review, emphasis is placed on molecular mechanisms and biomarkers that can be used as predictors of asthma in children.

Induced Sputum Nitrite Levels Correlate with Clinical Asthma Parameters in Children Aged 7-18 Years with Mild to Moderate Persistent Asthma

PURPOSE

The objective of this study is to measure levels of nitrites in induced sputum in children with asthma and correlate it with clinical asthma parameters.

METHOD

This prospective observational study was done in PGIMER, Dr. Ram Manohar Lohia Hospital, New Delhi, on 91 children aged 7-18 years with mild and moderate persistent asthma. Patients were specifically evaluated for five clinical parameters of asthma (i.e. Days of acute exacerbations, use of salbutamol as rescue medication, emergency visits, nights with cough, days of school absence) and induced sputum nitrite levels was done at the time of enrollment and 3 months after treatment with inhaled budesonide.

RESULTS

The mean age of subjects was 10.79 ± 2.563yrs. Six (6.59%) patients were not able to perform induced sputum, eighty five (93.41%) patients were suitable for data analysis. There was significant reduction in sputum nitrite levels from 33.42 ± 22.04nmol/ml at enrollment to 11.72 ± 5.61 nmol/ml (P < 0.0005) after 3 months of inhaled budesonide therapy. Significant positive correlation was found between reduction in sputum nitrite level and control of asthma symptoms: Days of acute exacerbations(r value = 0.548, P value = 0.0001), Days of salbutamol use as rescue medication (r value = 0.431, P value =< 0.0001), Number of emergency visits(r value = 0.414, P value = 0.0001), Nights with cough (r value = 0.259, P value = 0.0169), Days of school absence(r value = 0.411, P value = 0.0001). Sputum nitrite levels were significantly higher in moderate persistent asthmatics as compared to mild at the time of enrollment (P < 0.0005), which shows that induced sputum nitrite levels correlate with asthma severity.

CONCLUSIONS

This study confirms that nitrites in induced sputum correlate well with clinical asthma parameters and asthma severity in children and is a simple, non invasive, and cheap method which can be used as a parameter for monitoring of asthma.

Correlation between nitrites in induced sputum and asthma symptoms in asthmatic schoolchildren

OBJECTIVE

To determine if nitrites (nitric oxide metabolites) measured in induced sputum decrease and correlate with improvement of clinical asthma symptoms after treatment, we performed a prospective longitudinal study in a tertiary care hospital in Arequipa, Peru.

METHODS

In 95 schoolchildren with mild and moderate persistent asthma we determined nitrites in induced sputum samples (measured using the Griess assay). Clinical parameters and exercise bronchial challenge (EBC) test were performed twice, at baseline and after 3 months of beclomethasone-dipropionate treatment (median doses: 300 mcg/day, IQR: 300-450).

RESULTS

Sixty out of 95 children completed the study (median age of 9-year [IQR: 7-13]). A significant change in sputum nitrites levels between admission and the end of the study was observed (34.4 nmol/ml [IQR:18.2-58.4] and 11.2 nmol/ml [6-20.1], respectively, P = < 0.0001). Also a significant correlation between decrease of sputum nitrites levels and improvement of clinical parameters (acute exacerbations [r = 0.361, P = 0.005]; use of salbutamol [r = 0.322, P = 0.013]; emergency visits [r = 0.275, P = 0.033]; and school absence [r = 0.41, P = 0.001]) from admission to the end of the study was found. However, sputum nitrites levels did not correlated with peripherical blood eosinophils or serum IgE levels or with EBC test at any point of the study. The decrease of sputum nitrites levels after the treatment was significant in each asthma group (mild and moderate), but not between groups.

CONCLUSION

This study showed that measured nitrite in induced sputum (a simple and cheap non-invasive method) is a good alternative for monitoring asthmatic treatment in schoolchildren.

The Peru Urban versus Rural Asthma (PURA) Study: methods and baseline quality control data from a cross-sectional investigation into the prevalence, severity, genetics, immunology and environmental factors affecting asthma in adolescence in Peru

OBJECTIVES

According to a large-scale international survey, Peru has one of the highest prevalences of asthma worldwide; however, data from this survey were limited to participants from urban Lima. The authors sought to characterise the epidemiology of asthma in Peru in two regions with disparate degrees of urbanisation. In this manuscript, the authors summarise the study design and implementation.

DESIGN

A cross-sectional study.

PARTICIPANTS

Using census data of 13-15-year-old adolescents from two communities in Peru, the authors invited a random sample of participants in Lima (n=725) and all adolescents in Tumbes (n=716) to participate in our study.

PRIMARY AND SECONDARY OUTCOME MEASURES

The authors asked participants to complete a questionnaire on asthma symptoms, environmental exposures and socio-demographics and to undergo spirometry before and after bronchodilator, skin allergy testing and exhaled nitric oxide testing. The authors obtained blood samples for haematocrit, total IgE levels, vitamin D levels and DNA in all participants and measured indoor particulate matter concentrations for 48 h in a random subset of 70-100 households at each site.

RESULTS

Of 1851 eligible participants, 1441 (78%) were enrolled and 1159 (80% of enrolled) completed all physical tests. 1283 (89%) performed spirometry according to standard guidelines, of which 86% of prebronchodilator tests and 92% of postbronchodilator tests were acceptable and reproducible. 92% of allergy skin tests had an adequate negative control. The authors collected blood from 1146 participants (79%) and saliva samples from 148 participants (9%). Overall amounts of DNA obtained from blood or saliva were 25.8 μg, with a 260/280 ratio of 1.86.

CONCLUSIONS

This study will contribute to the characterisation of a variety of risk factors for asthma, including urbanisation, total IgE levels, vitamin D levels and candidate genes, in a resource-poor setting. The authors present data to support high quality of survey, allergic, spirometric and genetic data collected in our study.