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16-11-2011 | Cardiometabolic | Article

Reduced HDL apolipoprotein ratio linked to increased risk for heart attack in young


Free abstract

MedWire News: A reduced high-density lipoprotein (HDL) apolipoprotein A-I (apoA-I)/apoC-III ratio and increased HDL oxidation potential is linked to increased risk for myocardial infarction (MI) in the young, researchers say.

The possibility that such changes may serve as marker for the early identification of young individuals at high risk for a life-threatening acute MI should be further explored in a prospective epidemiologic study, say Kyriakos Kypreos (University of Patras, Greece) and colleagues.

They studied the structural characteristics of HDL in 20 patients who experienced their first MI when aged 35 years or younger. These patients were matched on the basis of age and gender to 20 control participants without a history of cardiovascular or thromboembolic disease.

ELISA analysis showed that MI patients had reduced apoA-I, apolipoprotein M, and paraxonase 1 levels, and had significantly elevated apoC-III levels compared with the control participants. Indeed, the ratio of HDL (apoA-I/apoC-III) was significantly lower in the MI patients, at 0.24, versus 4.88 in the control participants.

These structural alterations correlated with an increased HDL oxidation potential in the MI group, which was significantly increased 2.5-fold compared with the control group.

Electron microscopy showed no significant difference in average HDL diameter distribution between control participants and MI patients, suggesting the presence of different HDL subpopulations in MI and control participants, note the authors.

Indeed, electrophoresis showed that MI patients had reduced levels of HDL subpopulations pre-beta1a, pre-beta1b and alpha2 particles and elevated alpha1, alpha3, and pre-alpha4 particles compared with control patients.

The authors say that although the findings of their study are mainly qualitative, the changes in the apoA-I/apoC-III ratio and oxidation potential of HDL between the two groups could be a cause or effect of pathological conditions leading to an early acute MI.

Thus, "changes in HDL quality may be an important parameter in atheroprotection," they conclude in the journal Atherosclerosis.

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By Piriya Mahendra