Myocardial infarction patients show altered lipoprotein properties and functions when compared with stable angina pectoris patients

Several parameters and risk factors were compared between Korean male myocardial infarction (MI) patients (n = 10) and angina pectoris (AP) patients (n = 17) to search unique biomarkers for myocardial infarction (MI) in lipoprotein level. Individual serum and lipoprotein fractions (VLDL, LDL, HDL₂, HDL₃) were isolated and analyzed by lipid and protein determination and enzyme assay. The MI group was found to have a 25 and 30% higher serum cholesterol and triacylglycerol (TG) level than the AP group, respectively, however, their body mass index (BMI), LDL-cholesterol (C), HDL-C, and glucose levels fell within the normal range. MI patients were found to have an approximately two-fold higher level of serum IL-6 and an 18% lower serum apoA-I level than that of the AP group. LDL and HDL₂ fraction of the MI group were more enriched with TG than those of AP group. The increased TG was correlated well with the increased level of apoC-III in the same fraction. Cholesteryl ester transfer protein (CETP) activity and protein level were greatly increased in MI patients in the LDL and HDL₃ fractions. MI patients showed more severely oxidized LDL fraction than patients in the AP group, as well as the weakest antioxidant ability of serum. Conclusively, MI patients were found to have unique serum and lipoprotein characteristics including increased IL-6 and TG in serum, with CETP and apoC-III in the LDL and HDL fractions, as well as severely impaired antioxidant ability of HDL.