SAA is Found on ApoB-Containing Lipoproteins in Obese Diabetic Humans

In murine models of obesity/diabetes there is an increase in plasma SAA levels along with redistribution of SAA from high density lipoprotein (HDL) to apo-B containing lipoprotein particles, namely low density lipoprotein (LDL) and very low density lipoprotein (VLDL). The goal of this study was to determine if obesity is associated with similar SAA lipoprotein redistribution in humans. Three groups of obese individuals were recruited from a weight loss clinic: healthy obese (n=14), metabolic syndrome obese (n=8) and obese with type 2 diabetes (n=6). Plasma was separated into lipoprotein fractions by fast protein liquid chromatography (FPLC) and SAA was measured in lipid fractions using enzyme-linked immunosorbent assay (ELISA) and western blotting. Only the obese diabetic group had SAA detectable in apoB-containing lipoproteins, and SAA reverted back to HDL with active weight loss. In human subjects, SAA is found in apo-B containing lipoprotein particles only in obese subjects with type 2 diabetes, but not healthy obese, or obese subjects with metabolic syndrome.