👤 Constantinos C Tellis

Oxidative modification of apolipoprotein B-100 (apoB) containing particles and subsequent immune responses contribute to the pathogenesis of atherosclerosis. Circulating IgG and IgM apoB-containing immune complexes (apoB-IC) and autoantibodies to a malondialdehyde mimotope (anti-MDA-mimotope) serve as biomarkers of oxidative stress and immune activation in atherosclerotic cardiovascular disease. Elevated lipoprotein(a) [Lp(a)] is associated with increased oxidative burden and immune activation. To investigate the effect of lipid-lowering medications on IgG and IgM apoB-IC and IgG and IgM autoantibodies to an MDA-mimotope in individuals with elevated lipoprotein(a) [Lp(a)] concentrations. In this prospective study, patients (n = 70) with Lp(a) levels ≥ 75 nmol/L were assigned to 3 treatment regimens according to current guidelines: high-intensity statin monotherapy (n = 28), ezetimibe added to high-intensity statin (n = 31) and proprotein convertase subtilisin/kexin type 9 inhibitor (PCSK9i) added to high-intensity statin plus ezetimibe (n = 11). IgG and IgM apoB-IC and IgG and IgM anti-MDA-mimotope were measured at baseline and 3 months after treatment initiation. Patients had a mean age of 51 ± 15 years and 40% were male. Significant reductions in IgG apoB-IC levels were observed following treatment with high-intensity statins, add-on ezetimibe and add-on PCSK9i (by 18.3%, 17.5% and 25.5%, respectively, all p < 0.05). No significant changes in IgM apoB-IC, or IgG and IgM anti-MDA-mimotope levels were observed in any treatment group. In individuals with Lp(a) levels ≥ 75 nmol/L, high-intensity statins, add-on ezetimibe and add-on PCSK9i reduced IgG apoB-IC but did not affect IgM apoB-IC, or IgG and IgM anti-MDA-mimotope levels. The clinical significance of these findings warrants further investigation. Show less

Oxidized phospholipids (OxPLs) are bound to apolipoprotein B-100 (OxPL-apoB) and apolipoprotein(a) [OxPL-apo(a)] and are present freely within the phospholipid shell of apoB-containing lipoproteins. OxPLs have been linked with the pro-inflammatory properties of lipoprotein(a) [Lp(a)]. OxPLs carried on plasminogen (OxPL-PLG) may extend the time to fibrinolysis. To evaluate the effect of lipid-lowering medications on OxPLs levels in individuals with elevated Lp(a) concentrations. In this prospective study, patients (n = 70) with Lp(a) levels ≥75 nmol/L were assigned to 3 treatment regimens according to current guidelines: high-intensity statin monotherapy (n = 28), ezetimibe added to high-intensity statin (n = 31) and proprotein convertase subtilisin/kexin type 9 inhibitor (PCSK9i) added to high-intensity statin plus ezetimibe (n = 11). Follow-up duration was 3 months. Patients had a mean age of 51 ± 15 years, 40 % were male, 39 % were diagnosed with familial hypercholesterolemia, 16 % had atherosclerotic cardiovascular disease, and 36 %, 33 % and 15 % were at very high, high, and moderate cardiovascular risk, respectively. Lp(a) levels did not change significantly with high-intensity statin and add-on ezetimibe but significantly decreased with add-on PCSK9i treatment. OxPL-apoB and OxPL-apo(a) significantly increased, while OxPL-PLG significantly decreased with both high-intensity statin and add-on ezetimibe. Add-on PCSK9i treatment was associated with no significant changes in OxPL-apoB, OxPL-apo(a) and OxPL-PLG levels. Among patients with elevated Lp(a), both high-intensity statin and add-on ezetimibe significantly increased OxPL-apoB and OxPL-apo(a) levels, while significantly decreased OxPL-PLG levels. Add-on PCSK9i had no significant effect on OxPLs levels. The clinical implications of these findings should be further explored. Show less

APOC3 is produced mainly by the liver and intestine and approximately half of plasma APOC3 associates with HDL. Though it was believed that APOC3 associates with HDL by simple binding to preexisting particles, recent data support that biogenesis of APOC3-containing HDL (APOC3-HDL) requires Abca1. Moreover, APOC3-HDL contributes to plasma triglyceride homeostasis by preventing APOC3 association with triglyceride-rich lipoproteins. Interestingly, APOC3-HDL also shows positive correlation with the morbidly obese phenotype. However, the roles of APOC3 in HDL functionality and adipose tissue metabolic activity remain unknown. Therefore, here we investigated the direct effects of APOC3 expression on HDL structure and function, as well as white adipose tissue (WAT) and brown adipose tissue (BAT) metabolic activity. C57BL/6 mice were infected with an adenovirus expressing human APOC3 or a recombinant attenuated control adenovirus expressing green fluorescent protein and blood and tissue samples were collected at 5 days postinfection. HDL was then analyzed for its apolipoprotein and lipid composition and particle functionality. Additionally, purified mitochondria from BAT and WAT were analyzed for uncoupling protein 1, cytochrome c (Cytc), and Cytc oxidase subunit 4 protein levels as an indirect measure of their metabolic activity. Serum metabolomic analysis was performed by NMR. Combined, our data show that APOC3 modulates HDL structure and function, while it selectively promotes BAT metabolic activation. Show less