Lipid analysis of bronchoalveolar lavage fluid (BAL) by MALDI-TOF mass spectrometry and P-31 NMR spectroscopy

Despite the high clinical relevance, only the cellular moiety of bronchoalv eolar lavage (DAL) has been intensively investigated and is used for diagno sis purposes. On the other hand, the cell-free fluid is, by far, less chara cterized. Although this fluid represents a relatively simple mixture of onl y a few different phospholipids (mainly phosphatidylcholine, phosphatidylgl ycerol and cholesterol), methods for the routine analysis of these fluids a re still lacking. In the present investigation we have applied, for the fir st time, MALDI-TOF mass spectrometry, as well as IT NMR spectroscopy to the analysis of organic extracts of bronchoalveolar lavage fluids. BAL from di fferent mammals (rat, minipig, rabbit and man) were investigated and, for m eans of comparison, organic extracts of lung tissue were also examined. Bot h applied methods provide fast and reliable information on the lipid compos ition of the bronchoalveolar lavage. However, despite of its comparably low sensitivity, P-31 NMR spectroscopy detects all phospholipid species in a s ingle experiment and with the same sensitivity, whereas MALDI-TOF fails in the detection of phosphatidylethanolamine in the presence of higher quantit ies of phosphatidylcholine. In contrast, MALDI-TOF mass spectrometry is mor e suitable for the detection of cholesterol and the determination of the fa tty acid composition of the individual phospholipids, especially lysolipids . It will be shown that all BALs exhibit significant, species-dependent dif ferences that mainly concern the content of phosphatidylglycerol and lyso-p hosphatidylcholine. It is concluded that both methods are suitable tools in lipid research due to the (in comparison to alternative methods) simplicit y of performance. (C) 2001 Elsevier Science Ireland Ltd. All rights reserve d.