OxPLs‐Masking/Degradation Immune Assay: An “All‐Included” Analysis of Mechanisms Detoxifying Oxidized Phospholipids

Abstract

The manuscript discusses the use of circulating oxidized phospholipids (OxPLs) as potential disease biomarkers. Blood levels of OxPLs have been previously demonstrated to be strongly associated with cardiovascular disease. These data were obtained using an immune assay based on monoclonal antibody E06 which detects oxidized phosphatidylcholine. The impact of other classes of OxPLs on disease progression is not known. It is postulated that 1) other classes of OxPLs may contribute to cardiovascular disease and 2) both the absolute concentrations of OxPLs and the activity of detoxifying mechanisms are essential factors linking OxPLs with disease progression. Among such mechanisms is opsonization of OxPLs by endogenous antibodies and other plasma proteins. Furthermore, plasma contains enzymes degrading OxPLs. Experimental data from this study show that highly diluted blood plasma significantly reduces (“masks”) binding of E06, as well as another anti‐OxPL monoclonal antibody that recognizes oxidized phosphatidylethanolamine, to OxLDL. Potentially, sequestration or degradation of OxPLs by plasma proteins, antibodies or enzymes can ameliorate pathogenic effects of OxPLs, thus preventing disease onset. Based on these considerations, it is hypothesized that analysis of blood levels of “masking/degrading” proteins may provide important additional information complementary to the E06‐based assay and therefore improve its diagnostic value. Practical Applications: The manuscript discusses application of antibodies against OxPLs for their analysis as potential disease biomarkers. Plates are coated with OxLDL, blocked and incubated with either control buffer or plasma, which contains proteins and enzymes binding or degrading OxPLs present on OxLDL. Then the amount of remaining OxPLs is determined using monoclonal antibodies detecting OxPCs or OxPEs. The difference in signal intensities between the buffer‐ and plasma‐treated wells represents the activity of OxPLs‐masking/degradation.

Exploration of oxidized phosphocholine profile in non-small-cell lung cancer

“…Therefore, oxPCs themselves cannot be used as potential biomarkers of NSCLC due to their lack of specificity. However, Philippova et al (2019) pointed out that simultaneous determination of plasma levels of oxPCs and estimation of the detoxifying capacity of plasma to neutralize these lipids can significantly improve the diagnostic importance of oxPCs as a disease biomarker. In the context of our results, oxPCs might be rather considered as potential markers to distinguish between different NSCLC subtypes instead, however this requires more investigation, including the quantification of these lipids in plasma.…”

Increase in Plasma Oxidized Phosphatidylcholines (OxPCs) in Patients Presenting With ST-Elevation Myocardial Infarction (STEMI)

“…OxPC species, particularly fragmented forms, are bioactive and can rapidly interact with plasma proteins ( 9 ). Philippova et al ( 26 ) also suggested that in OxPC analysis, results of LC-MS/MS and immunoassay are related but not duplicates, as they observed weak correlations between free levels of 8 OxPC species measured by LC-MS/MS and E06 antibody in plasma of patients that underwent coronary angiography. They suggested that E06 recognizes both free form and covalent adducts of OxPCs which are bound to lipoproteins, cell membranes and other plasma proteins.…”