Fatty Acid Composition and Stoichiometry Determine the Angiogenesis Microenvironment

The current study tested the hypothesis of whether specific lipids may control angiogenic reactions. Using the chorioallantoic membrane assay of the chick embryo, new vessel formation was analyzed quantitatively by gas chromatography and mass spectrometry as well as bioinformatics tools including an angiogenesis analyzer. Our biochemical experiments showed that a specific lipid composition and stoichiometry determine the angiogenesis microenvironment to accelerate or inhibit vessel formation. Specific lipids of angiogenesis determinants in the vessel area and the non-vessel area were identified as nitrooleic acid, docosahexaenoic acid (DHA), eicosapentaenoic acid (EPA), palmitic acid, oleic acid, linoleic acid, linolenic acid, epoxyoleic acid, lysophosphatidylcholine (LPC), cholesterol, 7-ketocholesterol, and docosahexaenoyl lysophosphatidylcholine (DHA-LPC). Vessel formation happens on the surface area of the hydrophilic membrane of the yolk. Our biochemical data demonstrated that angiogenesis was followed in the white lipid complex area to generate more branches, junctions, segments, and extremities. We analyzed lipid fragments in the vessel, non-vessel, and albumen area to show that each area contains a specific lipid composition and stoichiometry. Mass spectrometry data demonstrated that the vessel area has higher concentrations of nitrooleic acid, palmitic acid, stearic acid, LPC, lysophosphatidylethanolamine, cholesterol, oleic acid, linoleic acid, 7-ketocholesterol, and DHA-LPC; however, DHA and EPA were abundant in the hydrophobic non-vessel area. The purpose of vessel formation is to wrap up the yolk area to transport nutrients including specific fatty acids. Besides, angiogenesis requires aqueous albumen shown by distance-dependent vessel formation from albumen and oxygen. Higher concentrations of fatty acids are required for energy and carbon structure from the carbon-carbon bond, membrane building blocks, and amphiphilic detergent to solubilize a hydrophobic environment in the aqueous blood layer. The current study may guide that the uncovered hydrophobic or zwitterionic molecules such as DHA and DHA-LPC may control angiogenesis as antiangiogenic or proangiogenic molecules as potential drug targets for treating uncontrolled angiogenesis-related diseases, including diabetic retinopathy and age-related macular degeneration.