Oxidized phospholipids on apolipoprotein B-100 among black US adults with and without PCSK9 loss-of-function variants

Abstract Background High oxidized phospholipid-apolipoprotein B-100 (OxPL-apoB) levels are associated with an increased risk for coronary heart disease (CHD). Genetic PCSK9 loss-of-function (LOF) variants result in life-long lower levels of LDL-C and lipoprotein(a) and reduced CHD risk, but the association with OxPL-apoB is unknown. Purpose To estimate the association between PCSK9 LOF variants and OxPL-apoB levels among black adults. Methods Genotyping for LOF variants (Y142X and C679X) was conducted for 10,196 black Reasons for Geographic And Racial Differences in Stroke study participants. OxPL-apoB was measured using antibody E06 for all participants with LOF variants (n=241) and randomly selected participants, matched at a 1:3 ratio, without LOF variants (n=723). Low OxPL-apoB was defined as the bottom quartile of the population distribution (<1.6 nM). Prevalence ratios (PR) and 95% confidence intervals (CI) were calculated for the association between PCSK9 LOF variants and low OxPL-apoB levels adjusting for age, sex, and estimated glomerular filtration rate. Results Adults with versus without PCSK9 LOF variants had lower LDL-C and lipoprotein(a) and were less likely to be taking a statin. (Table) A higher proportion of adults with versus without PCSK9 LOF variants had low OxPL-apoB levels (30.3 vs 23.4, p=0.03). After adjustment for covariates, the PR of low OxPL-apoB was increased for participants with compared to without LOF variants (PR 1.31, 95% CI 1.00, 1.72). Characteristics of REGARDS participants PCSK9 loss-of-function variant p-value Yes (n=241) No (n=723) Age, years, mean (SD) 63.7 (9.2) 63.8 (8.6) 0.81 Female, % 61.4 60.6 0.82 Diabetes, % 34.4 27.4 0.04 LDL-C, mg/dL, mean (SD) 85 (32) 118 (37) <0.001 Lp(a), nmol/L, median (25th, 75th percentile) 63.2 (30.4, 119.6) 80.4 (39.7, 138.4) 0.02 Statin use, % 13.3 30.4 <0.001 OxPL-apoB <1.6 nM, % 30.3 23.4 0.03 Abbreviations: LDL-C, low-density lipoprotein cholesterol; Lp(a), lipoprotein(a); LOF, loss-of-function; nM, nanomolar; OxPL-apoB, oxidized phospholipids on apolipoprotein B-100; PCSK9, proprotein convertase subtilisin/kexin type-9; REGARDS, REasons for Geographic And Racial Differences in Stroke; SD, standard deviation. Conclusion Among black adults, PCSK9 LOF variants were associated with lower OxPL-apoB levels. Acknowledgement/Funding Industry/academic collaboration between Amgen Inc., University of Alabama at Birmingham and the Icahn School of Medicine at Mt. Sinai; and U01NS041588