Lipid metabolite levels of prostaglandin D2 and eicosapentaenoic acid recovered from bronchoalveolar lavage fluid correlate with lung function of chronic obstructive pulmonary disease patients and controls

One-step global profiling of analyte (mRNA, protein, metabolite) biomarkers may soon replace conventional blood and histological/biopsy diagnostics technologies. It is important to establish whether the numerous blood and other body fluid-derived potential novel diagnostics will be sufficiently efficacious and precise to replace, for example, imaging and functional diagnostic tests. Currently, imaging technologies and spirometry are indispensable for the diagnosis and management of chronic obstructive pulmonary disease (COPD). To validate the concept of using body fluid biomarkers in COPD and to address the question of whether biomarker levels correlate with lung function, we measured the level of a number of biologically relevant lipids and metabolites in the bronchoalveolar lavage (BAL) fluid of COPD and control subjects and examined whether these correlate with numeric parameters of lung function. Both the diagnosis and management of COPD rely on costly and labor intensive lung function tests. Thus, there is an imminent need to replace the current diagnostic approaches with simpler clinical assays. As a first step, we demonstrate proof of principle; the correlation of lipid biomarkers as measured by LC-MS with lung function. In the apparently BAL-accessible fluid compartment, the total recovered lipid metabolite amount, particularly prostaglandin D-2 and eicosapentaenoic acid show a remarkable linear correlation with lung function (R-2 > 0.7). The study outcome is encouraging for the continuation of the work toward the measurement of lipid metabolite levels in more easily obtainable biological fluids such as sputum, exhaled air condensate, urine and plasma.