Lipidomic analysis of platelet senescence

BACKGROUND: A hallmark of platelet (PLT) storage lesion is the loss of PLT lipids. Due to technical limitations a detailed lipidomic analysis of plateletpheresis products during storage was so far not available. STUDY DESIGN AND METHODS: Fifty plateletpheresis products were stored for 5 days at 22°C under agitation. Each day plasma and PLTs were isolated by gel filtration and lipid species analyzed by electrospray ionization tandem mass spectrometry. RESULTS: During 5 days of storage the total lipid content decreased by 10% in PLTs and increased by 5% in plasma. We observed the following changes in lipid class fractions during storage relative to the day of preparation: increases of 69% ceramide (Cer), 32% lysophosphatidylcholine (LPC), and 49% cholesteryl esters (CE) and a decrease of 10% free cholesterol (FC) in PLTs and elevation of 43% LPC and 14% CE and a decline of 20% phosphatidylcholine (PC) and 24% FC in plasma. Significant lipid species shifts were observed for phosphatidylserine, Cer, and LPC. Correlation analysis of lipid changes in plasma indicated that lecithin-cholesterol-acyltransferase (LCAT) activity may be responsible for the shift in plasma lipid composition. These lipid changes correlated between plasma and PLTs for LPC, FC, and CE fractions. CONCLUSIONS: This study presents for the first time detailed lipid species profiles of PLTs and plasma during storage of PLT concentrates. These data provide clear evidence for LCAT-mediated esterification of FC and LPC generation in the plasma of PLT concentrates. Moreover, we showed evidence that these changes also impact PLT lipid composition.