Figures & data
Figure 1 The markers of oxidative stress are derived from different cells and cell compartments in the alveolar or bronchiolar wall. Neutrophilic granulocytes express myeloperoxidase (MPO) and eosinophilic granulocytes are endowed with eosinophilic peroxidase (EPO). Inducible nitric oxide synthase (iNOS) is expressed in the inflamatory cells and bronchial epithelium. 4-hydroxy-2-nonenal (4-HNE) and 3-nitrotyrosine can be detected in a variety of cell types. Hydrogen peroxide (H2O2), nitric oxide (NO), carbon monoxide (CO), and 8-isoprostane (8-iso) represent widely investigated markers in the exhaled air/exhaled breath condensate.
Table 1 The principal noninvasive methods in assessing airway inflammation and oxidative stress from patients with known or suspected obstructive pulmonary disease. The list includes some markers that already are in clinical use as well as several markers in experimental use
Table 2 Potential noninvasive oxidant biomarkers for the assessment of asthma, COPD, their differential diagnosis and phenotypes by combining the existent knowledge and future technologies
Figure 2 Future strategies for the discovery of new biomarkers in asthma and COPD, their diagnosis, differential diagnosis and assessment of the COPD phenotypes. The methods include microarray and proteomics combined with novel technologies. In these studies, protein expression has multiple advantages compared to gene expression, since proteins and not genes finally determine cellular function. Methods such as metabolomics (analysis of low molecular weight molecules from exhaled breath condensate), lipodomics and sputome (proteomics from induced sputum) have been evaluated and are ready for clinical prospective studies in asthma and COPD. Microarray/proteomics obtained from lung tissue, bronchial brushings and/or bronchoalveolar lavage have been conducted in asthma and/or COPD, and their extrapolation to noninvasive samples is being investigated in many laboratories.
