Oxidized lipoproteins and endothelium

Area of Science:

• Cardiovascular Biology
• Cellular Stress Response
• Atherosclerosis Research

Background:

• The endothelium, a crucial inner lining of blood vessels, is an initial site affected by pro-atherosclerotic processes.
• Oxidized low-density lipoproteins (oxLDL) are cytotoxic and can disrupt endothelial cell function, potentially leading to cell death or activating protective stress responses.

Purpose of the Study:

• To investigate the effect of chemically oxidized low-density lipoproteins on human endothelial cells.
• To determine if oxLDL induces stress responses, specifically heat shock protein synthesis, in endothelial cells.
• To examine the in vivo association of modified lipoproteins with endothelial cell apoptosis in an animal model of hypercholesterolemia.

Main Methods:

• Cultured human endothelial cells were exposed to chemically oxidized low-density lipoproteins.
• The synthesis of the inducible form of heat shock protein 70 (HSP70) was measured.
• Aortic sections from hypercholesterolemic rabbits were analyzed for the presence of modified lipoprotein epitopes and apoptotic endothelial cells.

Main Results:

• Chemically oxidized low-density lipoproteins induced the synthesis of inducible heat shock protein 70 in cultured human endothelial cells.
• Epitopes of oxidized low-density lipoproteins were found to be associated with apoptotic endothelial cells in the aortas of hypercholesterolemic rabbits.

Conclusions:

• Oxidized low-density lipoproteins can activate cellular stress responses, such as HSP70 synthesis, in endothelial cells.
• The findings suggest a dual role for oxLDL in endothelial cells, potentially contributing to both cell survival mechanisms and apoptosis, which are critical in the development of atherosclerosis.