156-OR: Apolipoprotein C-II Posttranslational Truncation Is Associated with Reduced Incident Cardiovascular Risk in Multiethnic Study of Atherosclerosis (MESA)

Higher truncated-to-native proteoform ratios of apolipoproteins (apo) C-I (C-I’/C-I) and C-II (C-II’/C-II) are associated with lower triglycerides (TG) and higher HDL levels. Here we examined the relationships of C-I’/C-II and C-II’/C-II, and total apo C-I and C-II concentrations with atherosclerotic cardiovascular disease (ASCVD) and coronary heart disease (CHD). Apo C-I and C-II proteoforms were measured by mass spectrometry immunoassay at baseline in 5,765 MESA participants followed for CHD (definite myocardial infarction, resuscitated cardiac arrest or fatal CHD) and ASCVD (CHD or stroke) for up to 17 years. Baseline total apo C-I and C-II levels were measured in a subgroup of 3,848 participants. After adjusting for age, gender, and race/ethnicity, lower C-II’/C-II was associated with both ASCVD and CHD (Figure). The association of C-II’/C-II with CHD remained significant after further adjusting for BMI, diabetes, systolic BP, eGFR, use of tobacco, statins, antihypertensive medications, total apoC-II, and plasma TG, but was abolished after adjusting for HDL. Neither ASCVD nor CHD were related to total apo C-I and C-II or CI’/CI. In conclusion, increased posttranslational apoC-II truncation (but not total apo C-I or C-II) is associated with reduced cardiovascular risk, possibly explained by differences in HDL cholesterol metabolism.