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Apolipoprotein A-I containing lipoproteins in coronary artery disease
P Puchois1, A Kandoussi, P Fievet
1Institut Pasteur, Lille, France.
Insights
Coronary artery disease lowers levels of LpA-I, a potentially antiatherogenic HDL particle, while LpA-I:A-II levels remain unchanged. This suggests LpA-I is specifically affected in atherosclerosis.
Area of Science:
- Cardiovascular Science
- Lipid Metabolism
- Biochemistry
Background:
- High-density lipoprotein (HDL) cholesterol levels are often decreased in coronary artery disease (CAD).
- HDL particles contain distinct apolipoprotein compositions, including LpA-I and LpA-I:A-II.
Purpose of the Study:
- To investigate how CAD affects specific HDL subfractions, LpA-I and LpA-I:A-II.
- To determine if LpA-I represents an antiatherogenic HDL fraction.
Main Methods:
- Plasma concentrations of LpA-I and LpA-I:A-II were measured.
- Subjects included normolipidemic males with (CAD(+)) and without (CAD(-)) angiographically defined CAD, plus age-matched controls.
Main Results:
- CAD(+) subjects showed lower HDL cholesterol, total apo A-I, and LpA-I compared to controls.
- CAD(+) subjects had lower HDL cholesterol and LpA-I compared to CAD(-) subjects.
- LpA-I levels were significantly decreased in CAD(+) individuals, while LpA-I:A-II levels remained unchanged.
Conclusions:
- Coronary artery disease is associated with a specific decrease in LpA-I levels.
- The distribution of apo A-I between LpA-I and LpA-I:A-II is altered in atherosclerotic patients.
- LpA-I may represent a protective, antiatherogenic HDL subfraction.
Abstract:
At least 2 main types of lipoprotein particles are identified within HDL. Those which contain apo A-I and apo A-II (LpA-I:A-II) and those which contain apo A-I but not apo A-II (LpA-I). This study was designed to elucidate to what degree the HDL cholesterol decrease observed in coronary artery disease affects these 2 types of lipoprotein particles. Concentrations of LpA-I:A-II and LpA-I were measured in plasma from 100 normolipidemic male subjects with angiographically defined coronary artery disease (CAD(+)) or without CAD (CAD(-)) and from 50 control subjects, matched for age. CAD(+) subjects had significantly lower levels of HDL cholesterol, total apo A-I, and LpA-I than controls. When compared to CAD(-) subjects, only their levels of HDL cholesterol and LpA-I were found lower. In both cases (CAD(+) vs CAD(-) and CAD(+) vs controls), LpA-I levels were decreased while LpA-I:A-II levels were unchanged. Even, when the levels of their total plasma lipids and lipoproteins are normal, atherosclerotic patients are characterized by a different distribution of apo A-I between LpA-I and LpA-I:A-II. These data support the view that LpA-I might represent the "antiatherogenic" fraction of HDL.