This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Carraro, S. Articles by Baraldi, E. Search for Related Content PubMed Articles by Carraro, S. Articles by Baraldi, E.

Metabolomics in Exhaled Breath Condensates

We appreciate Dr. Effros' comments on our article (1). The issue of oral contribution to exhaled breath condensate (EBC) is well accepted, although not fully clear (2). Lung auscultation can be contaminated by sounds coming from the upper airway tract. Spirometry can be affected by upper airway issues. So it is true for EBC. This fact does not lessen the value of any of these procedures. In addition, as reported in the article (1), our samples were almost completely dried. We decided not to dry them completely to avoid their precipitation and a consequent loss of the nonvolatile compounds. The drying process applied was nonetheless extensive (they were reduced to a volume of 10 µl), leading to the loss of most volatile compounds. Any residual volatile compounds were only at trace levels, and it is highly unlikely that they could have significantly affected our results.

We wish to stress that EBC samples were collected and processed in the same way for asthmatic and healthy children. The statistical methods used in the analysis of our results (pattern recognition methods) led to the identification of the compound patterns discriminating between healthy and asthmatic children, so we are confident that the differences identified are truly important for characterizing asthmatic subjects, whatever the exact source of each product within the respiratory tract. As Dr. Hunt says in his editorial (3), commenting on our article, these patterns may have a role both in classifying asthma subphenotypes and in identifying the biochemical disturbances that lead to asthma symptoms in each patient.

EBC is a new technique that still has its pitfalls, and we are well aware that our results need to be confirmed by further studies. The EBC technique nevertheless has great potential for the noninvasive study of the lung. Metabolomic analysis applied to EBC, enabling the simultaneous assessment of several biocompounds, definitively represents an innovative approach.

Silvia Carraro

University of Padova
Padova, Italy

Claude Guillou, Fabiano Reniero and Giuseppe Giordano

European Commission, Joint Research Centre
Ispra (VA), Italy

Eugenio Baraldi

University of Padova
Padova, Italy

FOOTNOTES

Conflict of Interest Statement: None of the authors has a financial relationship with a commercial entity that has an interest in the subject of this manuscript.

REFERENCES

1. Carraro S, Rezzi S, Reniero F, Héberger K, Giordano G, Zanconato S, Guillou C, Baraldi E. Metabolomics applied to exhaled breath condensate in childhood asthma. Am J Respir Crit Care Med 2007;175:986–990.[Abstract/Free Full Text]
2. Horvath I, Barnes P, Hunt J. Exhaled breath condensate: methodological recommendations and unresolved questions. Eur Respir J 2005;26:523–548.[Abstract/Free Full Text]
3. Hunt J. If it smells like a duck, it might be an asthma subphenotype. Am J Respir Crit Care Med 2007;175:975–976.[Free Full Text]

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Carraro, S. Articles by Baraldi, E. Search for Related Content PubMed Articles by Carraro, S. Articles by Baraldi, E.