Low density lipoprotein-containing circulating immune complexes and coronary atherosclerosis.

Area of Science:

• Cardiovascular Research
• Immunology
• Lipid Metabolism

Background:

• Coronary heart disease (CHD) is a leading cause of mortality.
• Atherogenic potential of patient serum has been observed in cell cultures.
• The specific components responsible for this atherogenicity are not fully understood.

Purpose of the Study:

• To investigate the role of circulating immune complexes (CICs) in the atherogenic potential of CHD patient serum.
• To determine the composition and lipid content of CICs in CHD patients.
• To assess the correlation between CICs and lipid accumulation in vascular cells.

Main Methods:

• Culturing human aortic smooth muscle cells.
• Treating patient serum with polyethylene glycol 6000 to isolate CICs.
• Measuring intracellular lipid and cholesterol content in cultured cells.
• Analyzing the protein and lipid composition of CICs, including apolipoproteins and lipoproteins.

Main Results:

• CHD patient serum significantly increased lipid content in cultured smooth muscle cells.
• Treatment removing CICs abolished the serum's atherogenic effect.
• Isolated CICs from CHD patients caused a significant rise in intracellular cholesterol.
• CICs contained apolipoprotein B (apo B) and had a lipid profile similar to low-density lipoproteins (LDL).
• High cholesterol and apo B levels in CICs strongly correlated with their atherogenic potential.

Conclusions:

• The atherogenic potential of CHD patient serum is attributed to LDL-containing immune complexes.
• These CICs contribute to lipid accumulation in vascular cells, a key process in atherosclerosis.
• Targeting or understanding these CICs may offer new therapeutic strategies for CHD.