Exhaled Breath Condensate—A Non-Invasive Approach for Diagnostic Methods in Asthma

Abstract

The pathophysiology of asthma has been intensively studied, but its underlying mechanisms such as airway inflammation, control of airway tone, and bronchial reactivity are still not completely explained. There is an urgent need to implement novel, non-invasive diagnostic tools that can help to investigate local airway inflammation and connect the molecular pathways with the broad spectrum of clinical manifestations of asthma. The new biomarkers of different asthma endotypes could be used to confirm diagnosis, predict asthma exacerbations, or evaluate treatment response. In this paper, we briefly describe the characteristics of exhaled breath condensate (EBC) that is considered to be an interesting source of biomarkers of lung disorders. We look at the composition of EBC, some aspects of the collection procedure, the proposed biomarkers for asthma, and its clinical implications. We also indicate the limitations of the method and potential strategies to standardize the procedure of EBC collection and analytical methods.

Potential Use of Exhaled Breath Condensate for Diagnosis of SARS-CoV-2 Infections: A Systematic Review and Meta-Analysis

“…In fact, such estimates were in line with earlier reports suggesting the alternative and innovative diagnostic procedures (e.g., Highly Sensitive High Performance Liquid Chromatography Laser Induced Fluorescence, photoacoustic spectroscopy and e-Nose) may represent a more rational choice to be coupled with EBC [ 5 , 6 ]. Nevertheless, diagnostic performances were substantially in line with those guaranteed by rapid antigenic testing [ 35 , 36 , 37 ], whose costs in terms of infrastructural, human and monetary resources are hardly comparable with the requests of EBC collection [ 2 , 20 , 38 ]. Moreover, application of Fagan’s nomogram [ 39 ] in order to cope with requirements of real-world settings hinted towards a further loss of diagnostic performances facing a lower circulation of the pathogen in the reference population.…”

Eosinophilic Asthma, Phenotypes-Endotypes and Current Biomarkers of Choice

“…The pH of the EBC is also evaluated and seems to be reduced in asthma exacerbations, whereas low lipotoxin A4 in EBC is associated with severe asthma and declining lung function. Mediators of oxidative stress such as hydrogen peroxide H 2 O 2 and 8-isoprostane were increased in steroid-naïve patients compared to the control [ 101 ]. Recently, there is increasing interest in conducting metabolomic analysis in EBC.…”

“…Recently, there is increasing interest in conducting metabolomic analysis in EBC. The ATS/ERS recommendations on the EBC sample collection procedure and the technical standards of EBC analysis were published in 2017 and should serve as a guide for future studies, as it seems to be a promising material for obtaining a better understanding of asthma pathology and management [ 101 ].…”

Inflammatory Biomarkers in Exhaled Breath Condensate: A Systematic Review

“…Molecular epidemiology studies, especially when involving children and the elderly, can reliably rely on biological matrices collected by non-invasive methods such as Exhaled Breath Condensate (EBC) and urine [ 8 , 9 ]. Cytokine profiling analyses play a crucial role in the early detection and follow-up of inflammatory processes.…”

“…To date, a variety of both commercial and homemade devices for the collection of EBC are available. The most widely used commercial devices are EcoScreen™, RTube™, and TurboDECCS™ [ 8 ]. The samplers differ in the cooling system type (pre-cooled sleeve or electric cooling system), providing temperatures ranging from 0 °C to −20 °C in the tube covering materials and in the electrical power [ 11 ].…”