Usefulness of Noninvasive Methods for the Study of Bronchial Inflammation in the Control of Patients with Asthma

Abstract

Bronchial asthma is one of the most prevalent respiratory conditions. Although it is defined as an inflammatory disease, the current guidelines for both diagnosis and follow-up of patients are based only on clinical and lung function parameters. Current research is focused on finding markers that can accurately predict future risk, and on assessing the ability of these markers to guide medical treatment and thus improve prognosis. The use of noninvasive methods to study airway inflammation is gaining increasing support. The study of eosinophils in induced sputum has proved useful for the diagnosis of asthma; however, its clinical implementation is complex. Some studies have shown that the measurement of exhaled nitric oxide (FeNO) may also be useful to establish disease phenotypes and improve control. Others have found that the measurement of pH and certain markers of oxidative stress, cytokines and prostanoids in exhaled breath condensate (EBC) may also be useful as well as the measurement of the temperature of exhaled breath and the analysis of volatile organic compounds (VOCs). In conclusion, since asthma is an inflammatory disease, it seems appropriate to try to control it through the study of airway inflammation using noninvasive methods. In this regard, the analysis of induced sputum cells has proved very useful, although the clinical implementation of this technique seems difficult. Other techniques such as temperature measurement, the analysis of FeNO, the analysis of the VOCs in exhaled breath, or the study of certain biomarkers in EBC require further study in order to determine their clinical applicability.

Fractional Exhaled Nitric Oxide: A Potential Biomarker in Allergic Rhinitis?

“…In addition, the present outcomes are consistent with the most relevant literature concerning this issue [31,32,33,34]. …”

Potential of Mass Spectrometry in Developing Clinical Laboratory Biomarkers of Nonvolatiles in Exhaled Breath

“…However, no such clinically significant marker is yet established. Immunoassay of a number of known proinflammatory cytokines has been reported for EBC (26 ), but studies often lack the reproducibility needed for clinical application. An immunoassay of surfactant protein A, a major locally produced protein involved in both surfactant and host-defense functions, was established for PEx (27 ).…”

Increased Levels of Interleukin-33 and Thymic Stromal Lymphopoietin in Exhaled Breath Condensate in Chronic Bronchial Asthma

“…It is a simple, noninvasive, and safe method of airway sampling [16]. EBC is collected using special condensing devices that freeze the exhaled air.…”