Distribution, fatty acid composition and apolipoprotein A-I immunoreactivity of high density lipoprotein subfractions in myocardial infarction
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P Marques-Vidal1, J B Ruidavets, J P Cambou
1INSERM U326 (Phospholipides membranaires, signalisation cellulaire et lipoprotéines), C.H.U. Purpan, Toulouse, France.
Insights
Patients with myocardial infarction have lower levels of HDL cholesterol and apolipoprotein A-I. Altered apolipoprotein A-I conformation and reduced HDL phospholipids may indicate increased cardiovascular risk.
Area of Science:
- Cardiovascular Science
- Lipid Metabolism
- Biochemistry
Background:
- High-density lipoprotein (HDL) plays a crucial role in reverse cholesterol transport.
- Dysfunctional HDL is associated with increased risk of cardiovascular diseases, including myocardial infarction.
- Apolipoprotein A-I (apo A-I) is the main protein component of HDL, and its conformation may influence HDL function.
Purpose of the Study:
- To investigate the differences in lipoprotein profiles, HDL subfractions, and apo A-I conformation between patients with myocardial infarction and controls.
- To identify specific HDL-related markers associated with myocardial infarction.
- To explore the relationship between HDL composition and apo A-I conformation in myocardial infarction patients.
Main Methods:
- Analysis of lipoprotein profile, HDL subfractions, apo A-I conformation (using monoclonal antibodies 5F6 and 3G10), HDL phospholipid levels, and fatty acid composition.
- Comparison between 119 myocardial infarction patients and 119 age-matched controls.
- Paired stepwise logistic regression to identify significant predictors of myocardial infarction.
Main Results:
- Patients with myocardial infarction had significantly lower levels of HDL cholesterol, HDL3 cholesterol, apo A-I, LpA-I, and LpA-I:A-II compared to controls.
- Apo A-I showed significantly different immunoreactivity against monoclonal antibody 5F6 in patients versus controls.
- Apo A-I, HDL3 cholesterol, and 5F6 immunoreactivity were significantly associated with myocardial infarction.
Conclusions:
- Apo A-I and HDL3 cholesterol are key markers differentiating myocardial infarction patients from controls.
- Altered apo A-I conformation, potentially due to lower HDL phospholipid and polyunsaturated fatty acid (PUFA) content, may contribute to the pathophysiology of myocardial infarction.
Abstract:
The lipoprotein profile, the HDL subfractions and the apolipoprotein (apo) A-I conformation of HDL were determined in 119 patients with myocardial infarction and 119 controls, paired for age. Apo A-I conformation was assessed by its immunoreactivity towards two monoclonal antibodies, 5F6 and 3G10. HDL phospholipid levels and fatty acid composition were also determined. HDL and HDL3 cholesterol, apo A-I, LpA-I and LpA-I:A-II levels were significantly lower in patients than in controls, whereas the levels of total and LDL-cholesterol and of apo B were not different. Apo A-I immunoreactivity against MAb 5F6 was significantly better in patients than in controls, while the immunoreactivity against 3G10 was similar. Paired stepwise logistic regression showed only apo A-I, HDL3 cholesterol and 5F6 immunoreactivity to be significantly related to myocardial infarction. After adjustment for HDL cholesterol, lower levels of HDL phospholipids and polyunsaturated fatty acids (PUFA) were found in patients compared with controls. Hence, of all HDL markers, apo A-I and HDL3 cholesterol appear to be the most informative. Also, lower HDL phospholipid and PUFA content may explain a different apo A-I conformation in patients with myocardial infarction.