ApoCIII glycoforms determination and proteomic analysis in plasma of coronary patients with different ApoCIII levels .

BACKGROUND:The aims of this study were:i) to analyze and quantify the apolipoproteinCIIIglycoforms characterized by none, one or two sialic acids,(having different lipoprotein lipase-LPLinhibitoryactivity), ii) to assess their relationship with LPL activity and ApoA-V in CAD patients,iii) to analyze some previously identified plasma proteins in relation to lipids status.METHODS: ApoCIII glycoforms in four groups of patients (from “Verona Heart Study” biobank,)classified according to the total plasma concentration of ApoCIII and different triglyceride (TG)levels, were analyzed by a classical (isoelectric focusing/western blotting) and by a shotgun MSapproach. LPL activity (Fluorescent assay) and ApoA-V concentration (ELISA assay) weredetermined, and their correlations with lipid metabolism parameters were analyzed. We alsovalidated by 2D-WB some plasma proteins previously identified by 2-DE analysis.RESULTS The distribution of the ApoCIII glycoforms in the selected groups of patients are relatedto the TG levels, particularly the mono-sialylated isoform (ApoCIII-1) prevails in patients with thehighest TG levels. Moreover, investigating the relation among ApoA-V level, LPL activity and theother parameters of lipid metabolism, we obtained useful information on their interplay as antiatherogenicfactors. ApoA-V concentration was found within the normal range, however higherthan previously reported. LPL activity measured as Vmax did not show significant correlations withApoCIII . Finally 2D-WB showed peculiar proteomic patterns of several proteins associated withelevated apoCIII plasma concentrations .CONCLUSIONS: As compared with the other ones, mono – sialylated isoform of apo CIII ispreferentially associated with TG levels. Samples with elevated levels of apoCIII are characterizedby specific proteomic patterns.