Oxidized Low-Density Lipoprotein: Preparation, Validation, and Use in Cell Models

Area of Science:

• Biochemistry
• Lipid Metabolism
• Cell Biology

Background:

• Plasma lipoproteins, including chylomicrons, VLDL, LDL, and HDL, are crucial for lipid transport.
• Low-density lipoprotein (LDL) is the primary carrier of cholesterol in circulation.
• Oxidized LDL (oxLDL) plays a significant role in the pathogenesis of cardiovascular diseases.

Purpose of the Study:

• To present a rapid ultracentrifugation method using iodixanol for efficient lipoprotein fractionation.
• To detail the preparation and characterization of native and oxidized LDL (oxLDL).
• To demonstrate the application of fluorescently labeled oxLDL for studying cellular uptake in macrophage and retinal pigment epithelial cell models.

Main Methods:

• Rapid ultracentrifugation with iodixanol for lipoprotein separation.
• Characterization of oxLDL using TBARS, conjugated diene formation, and agarose gel electrophoresis.
• In vitro cell models (THP-1 and ARPE-19) utilizing fluorescently labeled oxLDL (DiI-oxLDL) to study uptake.

Main Results:

• Iodixanol-based ultracentrifugation provides a faster, reproducible, and high-recovery method for lipoprotein isolation compared to traditional techniques.
• Oxidized LDL (oxLDL) can be effectively prepared and characterized for use in cellular studies.
• The study successfully visualizes and quantifies oxLDL uptake in macrophage and retinal pigment epithelial cells.

Conclusions:

• The rapid iodixanol ultracentrifugation method is highly effective for isolating native and preparing oxidized LDL (oxLDL).
• This method facilitates lipid peroxidation studies and characterization of LDL subclasses for functional and clinical research.
• Investigating oxLDL uptake in cellular models provides insights into atheroma formation and endothelial dysfunction, highlighting potential for further research in metabolic diseases.