|ZACEK, PETR - Forest Service (FS)|
|ROSENBERGER, THAD - University Of North Dakota|
Submitted to: Journal of Lipid Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/29/2016
Publication Date: 9/27/2016
Citation: Zacek, P., Bukowski, M.R., Rosenberger, T., Picklo, M.J. 2016. Quantitation of isobaric phosphatidylcholine species in human plasma using a hybrid quadrupole linear ion trap mass spectrometer. Journal of Lipid Research. 57:2225-2234.
Interpretive Summary: Specific types of phospholipids, a class of fats circulating in the blood, are often used as biomarkers for cardiovascular disease, diabetes, and Alzheimer’s disease. A drawback to the use of these biomarkers is that they are chemically very similar. These phospholipids often are the same size but have different types of fatty acids attached to them. The inability to distinguish between these types of phospholipids can cause misinterpretation of clinical results and can hinder the development of therapies. Using an instrument called a hybrid quadrupole linear ion trap mass spectrometer, we were able to develop an analytical method that is able to identify and quantify these phospholipids that have the same size but different structure. This method is rapid and provides more detailed information regarding bloods lipids. This work will assist clinical and basic scientists in improving biomarker analysis for human disease.
Technical Abstract: Phosphatidylcholine (PC) species in human plasma are used as biomarkers of disease. PC biomarkers are often limited by the inability to separate isobaric PC. In this work, we developed a targeted shotgun approach for analysis of isobaric and isomeric PC. This approach is comprised of two mass spectrometric (MS) methods: a precursor ion scanning of mass m/z 184 in positive mode (PIS m/z +184) and MS3 fragmentation in negative mode, both performed on a single instrument - a hybrid triple quadrupole / ion-trap mass spectrometer. The MS3 experiment identified the fatty acids (FA) composition and the relative abundance of isobaric and sn-1, sn-2 positional isomeric PC, which were subsequently combined with absolute quantitative data obtained by PIS m/z +184 scan. This approach was applied to the analysis of an NIST human blood plasma standard reference material (SRM 1950). We quantified more than 70 PCs and confirmed that a majority are present in isobaric and isomeric mixtures. The fatty acid content determined by this method was comparable to that obtained using gas chromatography with flame ionization detection, supporting the quantitative nature of this MS method. This methodology will provide more in-depth biomarker information for clinical and mechanistic studies.