Figure 1.

Overview of lipid class occurrence in cell and plasma compartments, major sources of plasma lipids, investigated lipid classes, captured fatty acid features, and assessed lipidomics levels. A, Lipids have several functions in the organism that determine their location in cells and tissues. They make up membranes and thereby determine membrane fluidity and function, serve as energy storage, exert intracellular signaling properties, and are precursors of hormones (steroids and eicosanoids). In plasma, FFAs are mostly transported bound to albumin, whereas complex lipids are transported as part of lipoproteins. Lipids are continuously exchanged between plasma and tissues. B, The plasma lipidome largely comprises lipids ingested from the diet, released from adipose tissue, or produced by the liver. The liver, in particular, is the central hub of lipid metabolism through lipoprotein production and de novo lipogenesis. C, The lipid classes depicted here are covered by Metabolon’s Complex Lipid Panel and represent most of the major lipid classes found in the human plasma. More detailed information on the molecular differences between the lipid classes is shown in Figure S1. D, Fatty acid feature information provided by the lipidomics platform. E, Metabolon’s Complex Lipid Panel allows investigation of lipids on different aggregated levels. The main results of this publication refer to “Within-class FA sum.” More details on the different naming conventions used throughout are in Table 1. This figure was produced using smart.servier.com. CE indicates cholesterylesters; FFA, free fatty acid; PEO, phosphatidylethanolamine ether; and PEP, phosphatidylethanolamine plasmalogen.