Apolipoprotein E phenotypes in patients with myocardial infarction.

Area of Science:

• Cardiovascular Genetics
• Lipid Metabolism
• Atherosclerosis Research

Background:

• Apolipoprotein E (apo E) genetic isoforms (E2, E3, E4) play a role in lipid metabolism and cardiovascular disease risk.
• Previous studies suggest associations between apo E isoforms and conditions like hyperlipoproteinemia and atherosclerosis.

Purpose of the Study:

• To investigate the frequencies of apo E isoforms in patients with myocardial infarction (MI) compared to healthy controls.
• To determine the specific role of apo E2 homozygosity in the context of MI and hyperlipoproteinemia.

Main Methods:

• Genotyping for apo E isoforms (E2, E3, E4) in 523 MI patients and 1031 blood donors.
• Comparison of isoform frequencies between patient and control groups.
• Analysis of lipid profiles (cholesterol, triglycerides) and clinical data in E2 homozygotes.

Main Results:

• Apo E4 frequency was significantly higher in MI patients than in controls.
• No significant difference in apo E3 or E2 frequencies was observed between groups.
• E2 homozygotes with MI consistently presented with hyperlipoproteinemia type III and elevated lipids.
• E2 homozygotes in the control group had primary dysbetalipoproteinemia but normal cholesterol levels.

Conclusions:

• Apo E4 is associated with an increased risk of myocardial infarction.
• E2 homozygotes with hyperlipoproteinemia type III have a substantially elevated risk for coronary atherosclerosis.
• The cardiovascular risk associated with E2 homozygosity may depend on plasma lipid levels, with normal levels potentially conferring lower risk.