Abstract 15817: Newly Determined Molecular Form Apolipoprotein A1 Des Q243 and the Ratio HDL/Apolipoprotein A1 Des Q243 are Significantly Correlated with Coronary Artery Disease

Abstract

BACKGROUND: Recently, molecularly modified forms of apolipoproteins have become available for routine measurement. Yet their significance as cardiac risk factors is controversial. HYPOTHESIS: We hypothesize that the newly determined posttranslational modification of apolipoprotein A1 “des Q243” and the ratio HDL/ apolipoprotein A1 des Q243 are associated with risk factors of heart diseases.

METHODS: We studied blood samples from one hundred patients presenting for cardiovascular evaluation. Collected patients' data included: demographic information, such as: age, gender, height and weight, past medical history of coronary artery disease (CAD), diabetes mellitus (DM) and myocardial infarction (MI), vital signs: BP and HR, cardiac diagnostics, such as: ECG and coronary artery stenosis (location and degrees), laboratory data, including: CK-MB (mg/dl), Troponin I (ng/ml), creatinine (mg/dl) and lipid profile. Electrospray ionization-based mass spectrometric immunoassay (ESI-MSIA) was used to ascertain the relative degree of C-terminal glutamine residue truncation "des-Q243" of apolipoprotein A-I (apoA1) (mg/dl). RESULTS: We tested one hundred patients with a mean age of 53 (SD +/-12) years, male (N = 59) and female (N = 41). Out of these patients, 38 (male = 25, female = 13) had been previously diagnosed with CAD, 25 (14, 11) had an angiographically confirmed diagnosis of MI and 32 (18, 14) had DM. The newly determined truncated form of Apo A1 "des Q243" (6.8 +/- 4.1) was found to be significantly correlated with elevated levels of troponin I (0.028 +/- 5.56) (Pearson Correlation (PC) = 0.314 Sig. 2-tailed = 0.021, N = 54) and stenosis in the territories of the right coronary artery (RCA) and left circumflex artery (LCx) (PC = 0.208 Sig.2-tailed = 0.038, N = 100). The ratio of HDL (41.055 +/- 11) / apo A1 des Q243 was significantly correlated with CAD (PC = 0.23 Sig. 2-tailed = 0.045, N = 73) and DM (PC = 0.231, Sig. 2-tailed = 0.049, N = 73). CONCLUSION: The newly determined molecularly modified ApoA1 “des Q243” is correlated with angiographically documented CAD and cardiac enzymes. The HDL/apoA1 des Q243 ratio is significantly correlated with the presence of coronary artery disease and diabetes mellitus. They hold promise as new cardiac risk factors.