Modified lipoprotein-derived lipid particles accumulate in human stenotic aortic valves

Area of Science:

• Cardiovascular Biology
• Lipid Metabolism
• Atherosclerosis Research

Background:

• Plasma lipoproteins accumulate in aortic valves during stenosis.
• Lipid composition of stenotic valves and atherosclerotic plaques share similarities.
• Proinflammatory lipid mediators derive from arachidonic acid, found in valve phospholipids.

Purpose of the Study:

• To compare lipid compositions of stenotic aortic valves and atherosclerotic plaque cores.
• To isolate and characterize extracellular lipid particles from human aortic valves.
• To investigate modifications of lipoproteins within stenotic aortic valves.

Main Methods:

• Comparison of lipid profiles in stenotic aortic valves and atherosclerotic plaque cores.
• Isolation and characterization of extracellular lipid particles from human stenotic and non-stenotic aortic valves.
• Analysis of lipid particle size, apoB-100 content, and lipid composition (sphingomyelin, phosphatidylcholine, lysophosphatidylcholine, unesterified cholesterol).

Main Results:

• Both pathological tissues were enriched in cholesteryl linoleate.
• Stenotic valves contained significantly more apoB-100 particles than non-stenotic valves.
• Valvular lipid particles from stenotic valves were larger, showed oxidative modifications, and had altered lipid profiles compared to plasma LDL.

Conclusions:

• Infiltrated plasma lipoproteins undergo oxidative and lipolytic modifications within stenotic aortic valves.
• These modified lipoproteins aggregate and fuse, forming larger lipid particles.
• These altered, aggregated lipid particles may contribute to the pathogenesis of human aortic stenosis.