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Background Niacin as an adjunct to statin treatment to reduce cardiovascular risk is questioned. Objective To evaluate interrelationships between the effects of niacin on mixed dyslipidemia and a spectrum of metabolic and inflammatory biomarkers. Methods Obese, nondiabetic, hypertriglyceridemic males ( n = 19) with low high-density lipoprotein–cholesterol levels received extended-release nicotinic acid for 8 weeks. Multiple biomarkers were measured using enzyme-linked immunosorbent assay, enzymatic/absorptiometric, or multiplex biochip assays. Treatment effects were determined for each variable and a differential correlation network created on the basis of univariate correlations between baseline and response to niacin treatment for all pairs of variables. Results Extended-release niacin treatment favoured normalization of plasma lipid and apolipoprotein profile. Plasma markers of inflammation, hepatic function, cellular adhesion and proliferation, and macrophage phenotype were attenuated; however, insulin resistance increased. Differential network analysis revealed that changes in triglycerides and high-density lipoprotein–cholesterol were closely linked; equally, niacin mediated reductions in total cholesterol, apolipoprotein B, low-density lipoprotein–cholesterol and lipoprotein(a) clustered together, as did homeostatic model assessment of insulin resistance, insulin, and interleukin-6 levels. Two clusters of inflammatory markers were identified, involving (1) intercellular adhesion molecule 1 and high-sensitive C-reactive protein and (2) soluble tumor necrosis factor receptors; and novel clusters involving matrix metallopeptidase 9 and apolipoprotein E, and adiponectin and cystatin C, respectively, were equally revealed. At lower stringency, lipid and insulin resistance clusters were linked; a C-reactive protein-centered cluster linked reduction in apolipoprotein CIII to intercellular adhesion molecule 1, gamma-glutamyltransferase, soluble tumor necrosis factor receptors, and E-selectin. Conclusion A niacin-mediated trend to normalize atherogenic mixed dyslipidemia was intimately linked to attenuation of biomarkers of inflammation, cell adhesion, hepatic dysfunction and cell proliferation, but to enhanced insulin resistance and plasma homocysteine elevation. [ABSTRACT FROM AUTHOR]

Background Statins impact the metabolism, concentrations, composition, and function of circulating lipoproteins. Objective We evaluated time course relationships between statin-mediated reduction in atherogenic apolipoprotein B (ApoB)–containing particles and dynamic intravascular remodeling of ApoAI-containing lipoprotein subpopulations in the mixed dyslipidemia of metabolic syndrome. Methods Insulin-resistant, hypertriglyceridemic, hypercholesterolemic, obese males (n = 12) were treated with pitavastatin (4 mg/d) and response evaluated at 6, 42, and 180 days. Results Reduction in low-density lipoprotein (LDL) cholesterol, ApoB, and triglycerides (TGs) was essentially complete at 42 days (–38%, –32%, and –35%, respectively); rapid reduction equally occurred in remnant cholesterol, ApoCII, CIII, and E levels (day 6; –35%, –50%, –23%, and –26%, respectively). Small dense LDLs (LDL4 and LDL5 subpopulations) predominated at baseline and were markedly reduced on treatment (–29% vs total LDL mass). Cholesteryl ester (CE) transfer protein activity and mass decreased progressively (–18% and –16%, respectively); concomitantly, TG depletion (up to –49%) and CE enrichment occurred in all high-density lipoprotein (HDL) particle subpopulations with normalization of CE/TG mass ratio at 180 days. ApoAI was redistributed from LpAI to LpAI:AII particles in HDL2a and HDL3a subpopulations; ApoCIII was preferentially depleted from LpAI:AII–rich particles on treatment. Conclusion Overall, statin action exhibits duality in mixed dyslipidemia, as CE transfer protein–mediated normalization of the HDL CE/TG core lags markedly behind subacute reduction in elevated levels of atherogenic ApoB-containing lipoproteins. Normalization of the HDL neutral lipid core is consistent with enhanced atheroprotective function. The HDL CE/TG ratio constitutes a metabolomic marker of perturbed HDL metabolism in insulin-resistant states, equally allowing monitoring of statin impact on HDL metabolism, structure, and function. [ABSTRACT FROM AUTHOR]

Background Low plasma levels of high-density lipoprotein-cholesterol (HDL-C) are typical of acute myocardial infarction (MI) and predict risk of recurrent cardiovascular events. The potential relationships between modifications in the molecular composition and the functionality of HDL subpopulations in acute MI however remain indeterminate. Methods and results ST segment elevation MI (STEMI) patients were recruited within 24 h after diagnosis (n = 16) and featured low HDL-C (− 31%, p < 0.05) and acute-phase inflammation (determined as marked elevations in C-reactive protein, serum amyloid A (SAA) and interleukin-6) as compared to age- and sex-matched controls (n = 10). STEMI plasma HDL and its subpopulations (HDL2b, 2a, 3a, 3b, 3c) displayed attenuated cholesterol efflux capacity from THP-1 cells (up to − 32%, p < 0.01, on a unit phospholipid mass basis) vs. controls. Plasma HDL and small, dense HDL3b and 3c subpopulations from STEMI patients exhibited reduced anti-oxidative activity (up to − 68%, p < 0.05, on a unit HDL mass basis). HDL subpopulations in STEMI were enriched in two proinflammatory bioactive lipids, lysophosphatidylcholine (up to 3.0-fold, p < 0.05) and phosphatidic acid (up to 8.4-fold, p < 0.05), depleted in apolipoprotein A-I (up to − 23%, p < 0.05) and enriched in SAA (up to + 10.2-fold, p < 0.05); such changes were most marked in the HDL3b subfraction. In vitro HDL enrichment in both lysophosphatidylcholine and phosphatidic acid exerted deleterious effects on HDL functionality. Conclusions In the early phase of STEMI, HDL particle subpopulations display marked, concomitant alterations in both lipidome and proteome which are implicated in impaired HDL functionality. Such modifications may act synergistically to confer novel deleterious biological activities to STEMI HDL. Significance Our present data highlight complex changes in the molecular composition and functionality of HDL particle subpopulations in the acute phase of STEMI, and for the first time, reveal that concomitant modifications in both the lipidome and proteome contribute to functional deficiencies in cholesterol efflux and antioxidative activities of HDL particles. These findings may provide new biomarkers and new insights in therapeutic strategy to reduce cardiovascular risk in this clinical setting where such net deficiency in HDL function, multiplied by low circulating HDL concentrations, can be expected to contribute to accelerated atherogenesis. [ABSTRACT FROM AUTHOR]