Advanced Oxidation Protein Products Are Strongly Associated with the Serum Levels and Lipid Contents of Lipoprotein Subclasses in Healthy Volunteers and Patients with Metabolic Syndrome.

The association between advanced oxidation protein products (AOPPs) and lipoprotein subclasses remains unexplored. Therefore, we performed comprehensive lipoprotein profiling of serum using NMR spectroscopy and examined the associations of lipoprotein subclasses with the serum levels of AOPPs in healthy volunteers (HVs) and patients with metabolic syndrome (MS). The serum levels of AOPPs were significantly positively correlated with the serum levels of very-low-density lipoprotein (VLDL), intermediate-density lipoprotein (IDL), and low-density lipoprotein (LDL); however, they were significantly negatively correlated with high-density lipoprotein (HDL). These lipoproteins (and their subclasses) differed markedly regarding the direction of correlations between their lipid contents and AOPPs. The strength of the correlations and the relative contributions of the subclasses to the correlations were different in the HVs and patients with MS. As revealed by orthogonal partial least squares discriminant analyses, the serum levels of IDL were strong determinants of AOPPs in the HVs, whereas the serum levels of VLDL and the lipid content of LDL were strong determinants in both groups. We conclude that IDL, VLDL, and LDL facilitate, whereas HDL diminishes the bioavailability of serum AOPPs. The presence of MS and the lipid contents of the subclasses affect the relationship between lipoproteins and AOPPs.