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Background Anacetrapib is the only cholesteryl ester transfer protein inhibitor proven to reduce coronary heart disease (CHD). However, its effects on reverse cholesterol transport have not been fully elucidated. Macrophage cholesterol efflux (CEC), the initial step of reverse cholesterol transport, is inversely associated with CHD and may be affected by sex as well as haptoglobin copy number variants among patients with diabetes mellitus. We investigated the effect of anacetrapib on CEC and whether this effect is modified by sex, diabetes mellitus, and haptoglobin polymorphism. Methods and Results A total of 574 participants with CHD were included from the DEFINE (Determining the Efficacy and Tolerability of CETP Inhibition With Anacetrapib) trial. CEC was measured at baseline and 24-week follow-up using J774 macrophages, boron dipyrromethene difluoride-labeled cholesterol, and apolipoprotein B-depleted plasma. Haptoglobin copy number variant was determined using an ELISA assay. Anacetrapib increased CEC, adjusted for baseline CEC, risk factors, and changes in lipids/apolipoproteins (standard β, 0.23; 95% CI, 0.05-0.41). This CEC-raising effect was seen only in men ( P interaction=0.002); no effect modification was seen by diabetes mellitus status. Among patients with diabetes mellitus, anacetrapib increased CEC in those with the normal 1-1 haptoglobin genotype (standard β, 0.42; 95% CI, 0.16-0.69) but not the dysfunctional 2-1/2-2 genotypes ( P interaction=0.02). Conclusions Among patients with CHD, anacetrapib at a dose linked to improved CHD outcomes significantly increased CEC independent of changes in high-density lipoprotein cholesterol or other lipids, with effect modification by sex and a novel pharmacogenomic interaction by haptoglobin genotype, suggesting a putative mechanism for reduced risk requiring validation.

We previously reported that reducing the expression of cholesteryl ester transfer protein (CETP) disrupts cholesterol homeostasis in SW872 cells and causes an ∼50% reduction in TG. The causes of this reduced TG content, investigated here, could not be attributed to changes in the differentiation status of CETP-deficient cells, nor was there evidence of endoplasmic reticulum (ER) stress. In short-term studies, the total flux of oleate through the TG biosynthetic pathway was not altered in CETP-deficient cells, although mRNA levels of some pathway enzymes were different. However, the conversion of diglyceride (DG) to TG was impaired. In longer-term studies, newly synthesized TG was not effectively transported to lipid droplets, yet this lipid did not accumulate in the ER, apparently due to elevated lipase activity in this organelle. DG, shown to be a novel CETP substrate, was also inefficiently transferred to lipid droplets. This may reduce TG synthesis on droplets by resident diacylglycerol acyltransferase. Overall, these data suggest that the decreased TG content of CETP-deficient cells arises from the reduced conversion of DG to TG in the ER and/or on the lipid droplet surface, and enhanced TG degradation in the ER due to its ineffective transport from this organelle., (Copyright © 2015 by the American Society for Biochemistry and Molecular Biology, Inc.)

Background: Cholesteryl ester transfer protein (CETP) has been considered as a possible target for treatment of cardiovascular disease. However, first clinical studies employing CETP inhibitors have failed to demonstrate clinical benefit. Additionally, we have previously shown that low endogenous plasma levels of CETP are associated with increased mortality in coronary artery disease (CAD) patients. We hypothesized that low CETP plasma levels are associated with decreased high-density lipoprotein (HDL) function., Materials and Methods: Serum HDL efflux capacity was measured in 154 patients of the Ludwigshafen Risk and Cardiovascular Health (LURIC) study displaying extremely low (< 0·68 μg/mL, n = 77) or high (> 2·13 μg/mL, n = 77) CETP concentrations in their plasma, respectively. The LURIC study is a prospective observational study of patients referred to coronary angiography at baseline with a median follow-up time of 7·75 years. Primary and secondary endpoints were cardiovascular and all-cause mortality, respectively., Results: High CETP patients showed a significant increase in the capacity of their plasma to mediate cholesterol efflux from cholesterol laden macrophages when compared to the efflux capacity observed in low CETP patients (+ 5·4%, P = 0·015). As shown by multiregression analysis, the impact of CETP on cholesterol efflux capacity was independent from classical risk and lifestyle factors, as well as from lipid parameters including HDL cholesterol, LDL cholesterol and triglycerides., Conclusions: Our findings indicate that low plasma concentrations of CETP might indeed lead to impaired HDL function within the reverse cholesterol transport pointing towards an atheroprotective role of CETP at least in patients with high risk of CAD., (© 2014 Stichting European Society for Clinical Investigation Journal Foundation.)

Cholesteryl ester transfer protein (CETP), a key regulator of high-density lipoprotein (HDL) metabolism, induces HDL remodeling by transferring lipids between apolipoprotein B-containing lipoproteins and HDL, and/or by promoting lipid transfer between HDL subparticles. In this study, we investigated the mechanism as to how CETP induces the generation of lipid-poor particles (pre-β-HDL) from HDL, which increases ATP-binding cassette transporter 1-mediated cholesterol efflux. This CETP-dependent HDL remodeling is enhanced by the CETP modulator dalcetrapib both in plasma and isolated HDL. The interaction of dalcetrapib with cysteine 13 of CETP is required, since this effect was abolished when using mutant CETP in which cysteine 13 was substituted for a serine residue. Other thiol-containing compounds were identified as CETP modulators interacting with cysteine 13 of CETP. In order to mimic dalcetrapib-bound CETP, mutant CETP proteins were prepared by replacing cysteine 13 with the bulky amino acid tyrosine or tryptophan. The resultant mutants showed virtually no CETP-dependent lipid transfer activity but demonstrated preserved CETP-dependent pre-β-HDL generation. Overall, these data demonstrate that the two functions of CETP i.e., cholesteryl ester transfer and HDL remodeling can be uncoupled by interaction of thiol-containing compounds with cysteine 13 of CETP or by introducing large amino acid residues in place of cysteine 13., (© 2013.)

Cholesteryl ester transfer protein (CETP) transfers cholesteryl ester and triglyceride between HDL and apoB-containing lipoproteins. Anacetrapib (ANA), a reversible inhibitor of CETP, raises HDL cholesterol and lowers LDL cholesterol in dyslipidemic patients. We previously demonstrated that ANA increases macrophage-to-feces reverse cholesterol transport and fecal cholesterol excretion in hamsters, and increased preβ HDL-dependent cholesterol efflux via ABCA1 in vitro. However, the effects of ANA on in vivo preβ HDL have not been characterized. In vitro, ANA inhibited the formation of preβ, however in ANA-treated dyslipidemic hamsters, preβ HDL levels (measured by two-dimensional gel electrophoresis) were increased, in contrast to in vitro findings. Because changes in plasma preβ HDL have been proposed to potentially affect markers of cholesterol absorption with other CETP inhibitors, a dual stable isotope method was used to directly measure cholesterol absorption in hamsters. ANA treatment of hamsters (on either dyslipidemic or normal diet) had no effect on cholesterol absorption, while dalcetrapib-treated hamsters displayed an increase in cholesterol absorption. Taken together, these data support the notion that ANA promotes preβ HDL functionality in vivo, with no effects on cholesterol absorption.

Preterm birth is the leading cause of neonatal mortality worldwide, and dyslipidemia is associated with preterm birth in observational studies. We use Mendelian randomization (MR) analyses to uncover the causal association between blood lipid levels and preterm birth. We extracted uncorrelated (R2 < 0.001) single-nucleotide polymorphisms strongly associated (p < 5 × 10–8) with blood lipids from genome wide association studies of FinnGen database and UK Biobank participants. Inverse variance weighted method was the main MR analysis. Sensitivity analyses including genetic pleiotropy, heterogeneity, and directionality of causality were conducted. The study included 115,082 participants with lipid measurements, 8,507 patients with preterm birth. Increasing apolipoprotein B (odds ratio (OR), 1.12[95 % CI, 1.02–1.23]; p = 0.019), low-density lipoprotein cholesterol (OR, 1.11[95 % CI, 1.00–1.22]; p = 0.040), non-high-density lipoprotein cholesterol (OR, 1.12[95 % CI, 1.01–1.24]; p = 0.026), remnant cholesterol (OR, 1.11[95 % CI, 1.00–1.23]; p = 0.047) and total free cholesterol (OR, 1.11[95 % CI, 1.01–1.23]; p = 0.037) were associated with increased risk of preterm delivery. Moreover, triglycerides in low-density lipoprotein were causally associated with the risk of PTB. Our sensitivity analysis yielded robust results, uncovering no evidence of horizontal pleiotropy or reverse causal relationships. Our investigation unveils the adverse impact of dyslipidemia on preterm birth, with a particular emphasis on the detrimental effect of elevated low-density lipoprotein cholesterol. [ABSTRACT FROM AUTHOR]

Background: Dysferlin-deficient limb-girdle muscular dystrophy type 2B (Dysf) mice are notorious for their mild phenotype. Raising plasma total cholesterol (CHOL) via apolipoprotein E (ApoE) knockout (KO) drastically exacerbates muscle wasting in Dysf mice. However, dysferlinopathic patients have abnormally reduced plasma high-density lipoprotein cholesterol (HDL-C) levels. The current study aimed to determine whether HDL-C lowering can exacerbate the mild phenotype of dysferlin-null mice. Methods: Human cholesteryl ester transfer protein (CETP), a plasma lipid transfer protein not found in mice that reduces HDL-C, and/or its optimal adapter protein human apolipoprotein B (ApoB), were overexpressed in Dysf mice. Mice received a 2% cholesterol diet from 2 months of age and characterized through ambulatory and hanging functional tests, plasma analyses, and muscle histology. Results: CETP/ApoB expression in Dysf mice caused reduced HDL-C (54.5%) and elevated ratio of CHOL/HDL-C (181.3%) compared to control Dysf mice in plasma, but without raising CHOL. Compared to the severe muscle pathology found in high CHOL Dysf/ApoE double knockout mice, Dysf/CETP/ApoB mice did not show significant changes in ambulation, hanging capacity, increases in damaged area, collagen deposition, or decreases in cross-sectional area and healthy myofibre coverage. Conclusions: CETP/ApoB over-expression in Dysf mice decreases HDL-C without increasing CHOL or exacerbating muscle pathology. High CHOL or nonHDL-C caused by ApoE KO, rather than low HDL-C, likely lead to rodent muscular dystrophy phenotype humanization. [ABSTRACT FROM AUTHOR]

On average, LDL particles are the most populous lipoprotein in serum under fasting conditions. For many reasons, it has been the primary target of lipid-lowering guidelines around the world. In the past 30 years, we have witnessed remarkable changes in each iteration of dyslipidaemia guidelines, with LDL-cholesterol (LDL-C) targets becoming lower and lower among patients at high and very high risk for atherosclerotic cardiovascular disease (ASCVD). The world over, goal attainment rates are low, and hence, ASCVD prevalence remains unacceptably high. Inadequate LDL-C lowering is a major issue in contemporary cardiovascular (CV) medicine. Another issue that vexes even the most astute clinician is that of 'residual risk', meaning the excess risk that remains even after LDL-C is appropriately reduced. In recent years, an important new component of residual risk has emerged: triglyceride-enriched lipoproteins or remnant lipoproteins. These precursors to LDL particles can assume outsized importance among patients with derangements in triglyceride metabolism (e.g. genetic variants, insulin resistance, and diabetes mellitus) and may be more atherogenic than LDL species. Consequently, to reduce total risk for acute CV events, the time has come to include the entire spectrum of apoB-containing lipoproteins in approaches to both risk evaluation and treatment. [ABSTRACT FROM AUTHOR]

Background: Osteoporosis and atherosclerosis frequently afflict older adults, and recent insights suggest a deeper connection between these conditions that surpasses mere aging effects. The ratio of non-high-density to high-density lipoprotein cholesterol (NHHR) has emerged as a novel lipid marker for evaluating the risk of cardiovascular diseases. Nonetheless, investigations into the correlation of the NHHR with the risk of developing osteoporosis remain unexplored. Methods: We collected NHHR and bone mineral density (BMD) data from 11,024 National Health and Nutrition Examination Survey (NHANES) participants between 2011 and 2018. Multivariate linear regression was employed to examine the correlation between BMD and NHHR. Smooth curves were employed to deal with the nonlinearity. To further account for the nonlinear link, we used a two-part linear regression model. The threshold effects were estimated using two components of a linear regression model. Subgroup and sensitivity analyses were carried out to ascertain the stability of the findings. Results: We discovered a negative relationship between the NHHR and lumbar spine BMD in all three models. An L-shaped curvilinear association existed between the NHHR and lumbar spine BMD, with a key inflection point of 6.91. The fully adjusted model showed that the BMD of the lumbar spine fell by 0.03 g/cm2 in those who were in the fourth quartile as opposed to the lowest quartile. The sensitivity analysis using unweighted logistic analysis verified the stability of the results. In addition, BMD in the nondiabetic group was more significantly affected by the negative effect of the NHHR in the subgroup analysis. Conclusions: According to this research, there appears to be a negative correlation between BMD and NHHR in US Adults. To clarify the precise physiological mechanisms by which the NHHR contributes to the onset of osteoporosis, more research is necessary. [ABSTRACT FROM AUTHOR]

The inflammatory corpuscle recombinant absents in melanoma 2 (AIM2) and cholesterol efflux protein ATP binding cassette transporter A1(ABCA1) have been reported to play opposing roles in atherosclerosis (AS) plaques. However, the relationship between AIM2 and ABCA1 remains unclear. In this study, we explored the potential connection between AIM2 and ABCA1 in the modulation of AS by bioinformatic analysis combined with in vitro experiments. The GEO database was used to obtain AS transcriptional profiling data; screen differentially expressed genes (DEGs) and construct a weighted gene co-expression network analysis (WGCNA) to obtain AS-related modules. Phorbol myristate acetate (PMA) was used to induce macrophage modelling in THP-1 cells, and ox-LDL was used to induce macrophage foam cell formation. The experiment was divided into Negative Control (NC) group, Model Control (MC) group, AIM2 overexpression + ox-LDL (OE AIM2 + ox-LDL) group, and AIM2 short hairpin RNA + ox-LDL (sh AIM2 + ox-LDL) group. The intracellular cholesterol efflux rate was detected by scintillation counting; high-performance liquid chromatography (HPLC) was used to detect intracellular cholesterol levels; apoptosis levels were detected by TUNEL kit; levels of inflammatory markers (IL-1β, IL-18, ROS, and GSH) were detected by ELISA kits; and levels of AIM2 and ABCA1 proteins were detected by Western blot. Bioinformatic analysis revealed that the turquoise module correlated most strongly with AS, and AIM2 and ABCA1 were co-expressed in the turquoise module with a trend towards negative correlation. In vitro experiments demonstrated that AIM2 inhibited macrophage cholesterol efflux, resulting in increased intracellular cholesterol levels and foam cell formation. Moreover, AIM2 had a synergistic effect with ox-LDL, exacerbating macrophage oxidative stress and inflammatory response. Silencing AIM2 ameliorated the above conditions. Furthermore, the protein expression levels of AIM2 and ABCA1 were consistent with the bioinformatic analysis, showing a negative correlation. AIM2 inhibits ABCA1 expression, causing abnormal cholesterol metabolism in macrophages and ultimately leading to foam cell formation. Inhibiting AIM2 may reverse this process. Overall, our study suggests that AIM2 is a reliable anti-inflammatory therapeutic target for AS. Inhibiting AIM2 expression may reduce foam cell formation and, consequently, inhibit the progression of AS plaques. [ABSTRACT FROM AUTHOR]

Coronary heart disease, also known as ischemic heart disease, is induced by atherosclerosis, which is initiated by subendothelial retention of lipoproteins. Plasma lipoproteins, including high density lipoprotein, low density lipoprotein (LDL), very low density lipoprotein, and chylomicron, are composed of a surface monolayer containing phospholipids and cholesterol and a hydrophobic core containing triglycerides and cholesteryl esters. Phospholipids play a crucial role in the binding of apolipoproteins and enzymes to lipoprotein surfaces, thereby regulating lipoprotein metabolism. High LDL-cholesterol is a well-known risk factor for coronary heart disease, and statins reduce the risk of coronary heart disease by lowering LDL-cholesterol levels. In contrast, the relationships of phospholipids in plasma lipoproteins with coronary heart disease have not yet been established. To further clarify the physiological and pathological roles of phospholipids, we have developed the simple high-throughput assays for quantifying all major phospholipid classes, namely phosphatidylcholine, phosphatidylethanolamine, phosphatidylserine, phosphatidic acid, phosphatidylinositol, phosphatidylglycerol + cardiolipin, and sphingomyelin, using combinations of specific enzymes and a fluorogenic probe. These enzymatic fluorometric assays will be helpful in elucidating the associations between phospholipid classes in plasma lipoproteins and coronary heart disease and in identifying phospholipid biomarkers. This review describes recent progress in the identification of phospholipid biomarkers of coronary heart disease. [ABSTRACT FROM AUTHOR]

Purpose of reviewCholesteryl ester transfer proteins (CETP) regulate plasma cholesterol levels by transferring cholesteryl esters (CEs) among lipoproteins. Lipoprotein cholesterol levels correlate with the risk factors for atherosclerotic cardiovascular disease (ASCVD). This article reviews recent research on CETP structure, lipid transfer mechanism, and its inhibition.Recent findingsGenetic deficiency in CETP is associated with a low plasma level of low-density lipoprotein cholesterol (LDL-C) and a profoundly elevated plasma level of high-density lipoprotein cholesterol (HDL-C), which correlates with a lower risk of atherosclerotic cardiovascular disease (ASCVD). However, a very high concentration of HDL-C also correlates with increased ASCVD mortality. Considering that the elevated CETP activity is a major determinant of the atherogenic dyslipidemia, i.e., pro-atherogenic reductions in HDL and LDL particle size, inhibition of CETP emerged as a promising pharmacological target during the past two decades. CETP inhibitors, including torcetrapib, dalcetrapib, evacetrapib, anacetrapib and obicetrapib, were designed and evaluated in phase III clinical trials for the treatment of ASCVD or dyslipidemia. Although these inhibitors increase in plasma HDL-C levels and/or reduce LDL-C levels, the poor efficacy against ASCVD ended interest in CETP as an anti-ASCVD target. Nevertheless, interest in CETP and the molecular mechanism by which it inhibits CE transfer among lipoproteins persisted. Insights into the structural-based CETP-lipoprotein interactions can unravel CETP inhibition machinery, which can hopefully guide the design of more effective CETP inhibitors that combat ASCVD. Individual-molecule 3D structures of CETP bound to lipoproteins provide a model for understanding the mechanism by which CETP mediates lipid transfer and which in turn, guide the rational design of new anti-ASCVD therapeutics.

Gold nanoparticles (AuNPs) are good candidates for donor material in energy transfer systems and can easily be functionalized with various ligands on the surface with Au–S bonding. Cyclodextrin (CD) forms inclusion complexes with fluorophores due to its unique structure for host–guest interaction. In this study, we fabricated βCD-functionalized AuNPs using different lengths of thiol ligands and recognized cholesterol to confirm the energy-transfer-based turn-on fluorescence mechanism. AuNP–βCD conjugated with various thiol ligands and quenched the fluorescein (Fl) dye, forming βCD-Fl inclusion complexes. As the distance between AuNPs and βCD decreased, the quenching efficiency became higher. The quenched fluorescence was recovered when the cholesterol replaced the Fl because of the stronger binding affinity of the cholesterol with βCD. The efficiency of cholesterol recognition was also affected by the energy transfer effect because the shorter βCD ligand had a higher fluorescence recovery. Furthermore, we fabricated a liposome with cholesterol embedded in the lipid bilayer membrane to mimic the cholesterol coexisting with lipids in human serum. These cellular cholesterols accelerated the replacement of the Fl molecules, resulting in a fluorescence recovery higher than that of pure lipid. These discoveries are expected to give guidance towards cholesterol sensors or energy-transfer-based biosensors using AuNPs. [ABSTRACT FROM AUTHOR]

BACKGROUND: Cholesterol efflux capacity (CEC) predicts cardiovascular disease independently of high-density lipoprotein (HDL) cholesterol levels. Isolated small HDL particles are potent promoters of macrophage CEC by the ABCA1 (ATPbinding cassette transporter A1) pathway, but the underlying mechanisms are unclear. METHODS: We used model system studies of reconstituted HDL and plasma from control and lecithin-cholesterol acyltransferase (LCAT)-deficient subjects to investigate the relationships among the sizes of HDL particles, the structure of APOA1 (apolipoprotein A1) in the different particles, and the CECs of plasma and isolated HDLs. RESULTS: We quantified macrophage and ABCA1 CEC of 4 distinct sizes of reconstituted HDL. CEC increased as particle size decreased. Tandem mass spectrometric analysis of chemically cross-linked peptides and molecular dynamics simulations of APOA1, the major protein of HDL, indicated that the mobility of C-terminus of that protein was markedly higher and flipped off the surface in the smallest particles. To explore the physiological relevance of the model system studies, we isolated HDL from LCAT-deficient subjects, whose small HDLs (like reconstituted HDLs) are discoidal and composed of APOA1, cholesterol, and phospholipid. Despite their very low plasma levels of HDL particles, these subjects had normal CEC. In both the LCAT-deficient subjects and control subjects, the CEC of isolated extra-small HDL (a mixture of extra-small and small HDL by calibrated ion mobility analysis) was 3- to 5-fold greater than that of the larger sizes of isolated HDL. Incubating LCAT-deficient plasma and control plasma with human LCAT converted extra-small and small HDL particles into larger particles, and it markedly inhibited CEC. CONCLUSIONS: We present a mechanism for the enhanced CEC of small HDLs. In smaller particles, the C-termini of the 2 antiparallel molecules of APOA1 are "flipped" off the lipid surface of HDL. This extended conformation allows them to engage with ABCA1. In contrast, the C-termini of larger HDLs are unable to interact productively with ABCA1 because they form a helical bundle that strongly adheres to the lipid on the particle. Enhanced CEC, as seen with the smaller particles, predicts decreased cardiovascular disease risk. Thus, extra-small and small HDLs may be key mediators and indicators of the cardioprotective effects of HDL. [ABSTRACT FROM AUTHOR]

Although statins have served as the cornerstone for pharmacological lowering of lipid levels in atherosclerotic cardiovascular disease (ASCVD) risk reduction, many patients are unable to achieve target doses of statin medication due to side effects or target levels of cholesterol reduction on statin monotherapy. The landscape of lipid-lowering strategies has expanded in recent years, with the emergence of therapies that make use of small interfering RNA (siRNA) and antisense oligonucleotides, in addition to traditional small-molecule agents. Non-statin therapies that have shown promising results in randomized controlled trials include adenosine triphosphate-citrate lyase inhibitors, proprotein convertase subtilisin/kexin 9 (PCSK9)-inhibiting antibodies and siRNA, omega-3 polyunsaturated fatty acids, and lipoprotein(a) gene-inhibiting siRNA and ASOs, in addition to older therapies such as ezetimibe. In contrast, cholesteryl ester transfer protein (CETP) inhibitors have shown less promising results in randomized trials. The purpose of this narrative review is to summarize the evidence for these medications, with a focus on phase III randomized trials. [ABSTRACT FROM AUTHOR]

Dyslipidemia, with changes in plasma membrane (PM) composition, is associated with hypertension, while rising PM cholesterol induces Na+ channel activity. We hypothesize that ablation of renal tubular ABCA1, a cholesterol efflux protein, leads to cholesterol- and Na+-dependent changes in blood pressure (BP). Transgenic mice (TgPAX8rtTA;tetO-Cre/+) expressing a doxycycline (dox)-inducible CRE recombinase were bred with mice expressing floxed ABCA1 to generate renal tubules deficient in ABCA1 (ABCA1FF). Tail-cuff systolic BP (SBP) was measured in mice on specific diets. Immunoblotting was performed on whole and PM protein lysates of kidney from mice completing experimental diets. Cortical PM of ABCA1FF showed reduced ABCA1 (60 ± 28%; n = 10, P < 0.05) compared with wild-type littermates (WT; n = 9). Tail-cuff SBP of ABCA1FF (n = 11) was not only greater post dox, but also during cholesterol or high Na+ feeding (P < 0.05) compared with WT mice (n = 15). A Na+-deficient diet abolished the difference, while 6 wk of cholesterol diet raised SBP in ABCA1FF compared with mice before cholesterol feeding (P < 0.05). No difference in α-ENaC protein abundance was noted in kidney lysate; however, γ-ENaC increased in ABCA1FF mice versus WT mice. In kidney membranes, NKCC2 abundance was greater in ABCA1FF versus WT mice. Cortical lysates of ABCA1FF mouse kidneys expressed less renin and angiotensin I receptor than WT mouse kidneys. Furosemide injection induced a greater diuretic effect in ABCA1FF (n = 7; 45.2 ± 8.7 µL/g body wt) versus WT (n = 7; 33.1 ± 6.9 µL/g body wt; P < 0.05) but amiloride did not. Tubular ABCA1 deficiency induces cholesterol-dependent rise in SBP and modest Na+ sensitivity of SBP, which we speculate is partly related to Na+ transporters and channels. NEW & NOTEWORTHY Cholesterol has been linked to greater Na+ channel activity in kidney cells, which may predispose to systemic hypertension. We showed that when ABCA1, a protein that removes cholesterol from tissues, is ablated from mouse kidneys, systemic blood pressure is greater than normal mice. Dietary cholesterol further increases blood pressure in transgenic mice, whereas low dietary salt intake reduced blood pressure to that of normal mice. Thus, we speculate that diseases and pharmaceuticals that reduce renal ABCA1 expression, like diabetes and calcineurin inhibitors, respectively, contribute to the prominence of hypertension in their clinical presentation. [ABSTRACT FROM AUTHOR]

BackgroundAortic valve calcification (AVC) shares pathological features with atherosclerosis. Lipoprotein components have been detected in aortic valve tissue, including HDL (high-density lipoprotein). HDL measures have inverse associations with cardiovascular disease, but relationships with long-term AVC progression are unclear. We investigated associations of HDL cholesterol, HDL-particle number and size, apoC3-defined HDL subtypes, and, secondarily, CETP (cholesteryl ester transfer protein) mass and activity, with long-term incidence and progression of AVC.MethodsWe used linear mixed-effects models to evaluate the associations of baseline HDL indices with AVC. AVC was quantified by Agatston scoring of up to 3 serial computed tomography scans over a median of 8.9 (maximum 11.2) years of follow-up in the Multi-Ethnic Study of Atherosclerosis (n=6784).ResultsAfter adjustment, higher concentrations of HDL-C (high-density lipoprotein cholesterol), HDL-P (HDL particles), large HDL-P, and apoC3-lacking HDL-C were significantly associated with lower incidence/progression of AVC. Neither small or medium HDL-P nor apoC3-containing HDL-C was significantly associated with AVC incidence/progression. When included together, a significant association was observed only for HDL-C, but not for HDL-P. Secondary analyses showed an inverse relationship between CETP mass, but not activity, and AVC incidence/progression. In exploratory assessments, inverse associations for HDL-C, HDL-P, large HDL-P, and apoC3-lacking HDL with AVC incidence/progression were more pronounced for older, male, and White participants. ApoC3-containing HDL-C only showed a positive association with AVC in these subgroups.ConclusionsIn a multiethnic population, HDL-C, HDL-P, large HDL-P, and apoC3-lacking HDL-C were inversely associated with long-term incidence and progression of AVC. Further investigation of HDL composition and mechanisms could be useful in understanding pathways that slow AVC.

Atherosclerosis constitutes the leading cause of death worldwide, surpassing violence. Given the physiopathological complexity it presents, it is important to recognize the genetic and atherogenic alterations associated with its development biology, which is useful for the prevention and control of obstructive vascular disease. The genetic inheritance pattern and the availability of candidate genes, such as PCSK9, APOB, APOA5, APOC3, ApoE, ABCA1, LPA, involved in the synthesis and metabolism of lipoproteins, show the possibility of establishing biomarkers related to alterations in plasma levels, demonstrating their risk association in different populations, which allows the identification of potential therapeutic targets. [ABSTRACT FROM AUTHOR]

Aim: To assess the implementation of the 2019 European Society of Cardiology (ESC)/European Atherosclerosis Society (EAS) guideline recommendations for lipid‐lowering therapies among more than 30 000 patients with type 1 diabetes (T1D) and type 2 diabetes (T2D) in a German and Austrian registry from 2020 to 2022. Materials and Methods: Registry data from 2020 and 2021 of 32 170 adult patients (8314 patients with T1D and 23 856 with T2D) were stratified according to the 2019 ESC/EAS risk categories, and guideline‐based low‐density lipoprotein cholesterol (LDL‐C) and non‐high‐density lipoprotein cholesterol (non‐HDL‐C) goal attainment was analysed. Results: In patients with T1D (median age 38.35 [20.51‐57.13] years), overall statin use was 19.3%, ezetimibe use was 2.2% and the use of proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitors or fibrates was less than 1%. In patients with T2D (median age 68.76 [58.86‐78.39] years), 45.7% received statins, 3.4% received ezetimibe, and fibrates and PCSK9 inhibitors were used by 1% and 0.1%, respectively. Among patients with T1D, 6.16% reached their risk‐based recommended LDL‐C goal of less than 55 mg/dL (very high risk), 10.97% of less than 70 mg/dL (high risk), and 69.50% of less than 100 mg/dL (moderate risk), respectively. In patients with T2D, 11.81% reached their risk‐based goal of LDL‐C less than 55 mg/dL, 16.25% of less than 70 mg/dL, and 51.33% of less than 100 mg/dL. Non‐HDL‐C goals were reached more often, with 15.3%, 25.52% and 91.61% in patients with T1D and 18.56%, 17.96% and 82.30% in patients with T2D for very high, high and moderate risk, respectively. Conclusion: Approximately 2 years after publication of the guidelines, LDL‐C and non‐HDL‐C goal attainment was rarely achieved in patients with T1D and T2D with a high or very high cardiovascular risk. [ABSTRACT FROM AUTHOR]

Background: Relationships between the subclasses of high-density lipoprotein (HDL) or low-density lipoprotein (LDL) and the risk of atherosclerotic cardiovascular disease have been studied, and using various methods, such as ultracentrifugation, electrophoresis, and nuclear magnetic resonance, for analysing lipoprotein subclasses. We established a method for HDL and LDL subclasses using anion-exchange high-performance liquid chromatography (AEX-HPLC) with a linear concentration gradient of sodium perchlorate (NaClO4). Method: In the AEX-HPLC, the subclasses of HDL and LDL were separated, and detected using a post-column reactor with an enzymatic cholesterol reagent, that contained cholesterol esterase, cholesterol oxidase, and peroxidase as major ingredients. LDL subclasses were divided based on the absolute value of first-derivative chromatogram. Result: Three HDL subclasses, HDL-P1, HDL-P2, and HDL-P3, and three LDL subclasses, LDL-P1, LDL-P2, and LDL-P3, were separated by AEX-HPLC, and detected in order. The major components of HDL-P2 and HDL-P3 were HDL3 and HDL2, respectively. The linearity was determined for each lipoprotein subclass. The coefficients of variation of cholesterol concentration of the subclasses for within-day assay (n = 10) and between-day assay (n = 10) ranged between 3.08–8.94% and 4.52–9.97%, respectively. Cholesterol levels in HDL-P1 of diabetic patients were positively correlated with oxidized LDL levels (r = 0.409, p = 0.002). Moreover, cholesterol levels in LDL-P2 and LDL-P3 were positively correlated with oxidized LDL levels (r = 0.393, p = 0.004 and r = 0.561, p < 0.001, respectively). Conclusion: AEX-HPLC may be highly suitable as an assay to clinically assess lipoprotein subclasses. [ABSTRACT FROM AUTHOR]

Betamethasone, a fluorinated and synthetic steroid, is a commonly used glucocorticoid. To our knowledge, no available studies exist concerning the hyperlipidemic effect of betamethasone dipropionate (BDP) in rabbits. Therefore, the current study was conducted to highlight the effects of intramuscular injection of BDP on lipid profile in rabbits, investigate the possible mechanism underlying the produced effects and evaluate the possible antihyperlipidemic effect of atorvastatin (ATR) and fenofibrate (FFB). For this purpose, twenty male New Zealand rabbits were classified into control, BDP (0.5 ml/kg B.wt/ IM/day/single dose), BDP+ATR; rabbits were IM injected with BDP, then they were orally given ATR (1.9 mg./kg. B.wt./ once/ day/ month) and group IV (BDP+FFB); rabbits were IM injected with BDP then they were orally given FFB (7.5 mg/kg B.wt/ once/ day/ month). The obtained result revealed that single IM injection of BDP produced a significant elevation in triglycerides, total cholesterol, LDL level with a significant decline in HDL in comparison to control group on the 3rd, 7th, 14th, 21st, 30th day of the experiment. On the 30th day of the experiment there was an increase in the ALT, AST, MDA, VCAM-1 as well as a significant decrease in TAC. Furthermore, BDP induced a significant increase in HMG-COA reductase gene expression and a significant decrease in lipoprotein lipase gene expression. Oral administration of ATR or FFB concurrently with BDP for a month succeeded in reducing the hyperlipidemia induced by BDP in rabbits. [ABSTRACT FROM AUTHOR]

Cholesterol derived from the host milieu forms a critical factor for mycobacterial pathogenesis. However, the molecular circuitry co-opted by Mycobacterium tuberculosis (Mtb) to accumulate cholesterol in host cells remains obscure. Here, we report that the coordinated action of WNT-responsive histone modifiers G9a (H3K9 methyltransferase) and SIRT6 (H3K9 deacetylase) orchestrate cholesterol build-up in in vitro and in vivo mouse models of Mtb infection. Mechanistically, G9a, along with SREBP2, drives the expression of cholesterol biosynthesis and uptake genes; while SIRT6 along with G9a represses the genes involved in cholesterol efflux. The accumulated cholesterol in Mtb infected macrophages promotes the expression of antioxidant genes leading to reduced oxidative stress, thereby supporting Mtb survival. In corroboration, loss-of-function of G9a in vitro and pharmacological inhibition in vivo; or utilization of BMDMs derived from Sirt6−/− mice or in vivo infection in haplo-insufficient Sirt6−/+ mice; hampered host cholesterol accumulation and restricted Mtb burden. These findings shed light on the novel roles of G9a and SIRT6 during Mtb infection and highlight the previously unknown contribution of host cholesterol in potentiating anti-oxidative responses for aiding Mtb survival. Author summary: Mycobacterium tuberculosis (Mtb) rewires the host molecular machinery and several cellular and immunological pathways to survive amidst its challenging microenvironments. Of these, deregulated lipid accumulation in host cells has been shown to play a critical role in the pathogenesis of Mtb. Biochemical analysis has indicated that cholesterol and cholesteryl esters form a major part of the accumulated lipids, and several reports support the relevance of cholesterol in aiding Mtb survival. Therefore, in this study, we aimed to determine the regulatory mechanisms that lead to cholesterol accumulation in host cells during Mtb infection. We find WNT signaling-dependent epigenetic factors G9a and SIRT6 to favor cholesterol accretion during Mtb infection by differentially regulating cholesterol biosynthesis/uptake and efflux genes. We found a distinct role of the accumulated cholesterol in the expression of antioxidant genes, that consequently leads to Mtb growth. Interestingly, perturbation of WNT, G9a, SIRT6, cholesterol accumulation genes or antioxidant genes, was found to restrict Mtb burden in vitro and lack of G9a or SIRT6 was also found to limit Mtb growth and lung pathology in an in vivo mouse model of tuberculosis (TB); thereby suggesting the targeting of these epigenetic factors as potential adjuvants for TB therapy. [ABSTRACT FROM AUTHOR]

Familial hypercholesterolaemia (FH) is a dominantly inherited disorder principally due to mutations in the low-density lipoprotein (LDL)-receptor pathway that causes markedly elevated plasma LDL-cholesterol concentration and premature coronary heart disease (CHD).[1] In addition to elevated LDL-cholesterol levels, there is evidence that alterations in reverse cholesterol transport (RCT) may also contribute to accelerating atherosclerosis in FH.[2] Excess cholesterol in macrophages is eliminated via the process of RCT in which cholesterol from peripheral tissues is transported to the liver for biliary excretion.[3] Cholesterol efflux from macrophages, the first step of RCT, plays a major role in anti-atherogenesis. Total cholesterol, LDL-cholesterol, HDL-cholesterol, apoA-I, apoA-II, apo(a) and Lp(a) concentrations were not significantly altered with -3FA treatment, nor were glucose, insulin concentrations and HOMA score. Whether -3FAs improve RCT in the latter stages by promoting hepatobiliary cholesterol excretion merits further investigation by detailed HDL kinetic and cholesterol balance studies. ABCA1 mediates cellular free cholesterol efflux to lipid-poor apoA-I whereas ABCG5 and SR-BI preferentially promotes the efflux of cellular cholesterol to mature apoA-I and/or apoA-II containing HDL particles. [Extracted from the article]

Elevated low-density lipoprotein cholesterol (LDL-C) is an important risk factor in the development of atherosclerotic cardiovascular disease (ASCVD). Inhibitors of proprotein convertase subtilisin/kexin type 9 (PCSK9), a negative regulator of LDL-C metabolism, have emerged as promising approaches for reducing elevated LDL-C levels. Here, we evaluated the cholesterol-lowering efficacy of virus-like particle (VLP) based vaccines that target epitopes found within the LDL receptor (LDL-R) binding domain of PCSK9. In both mice and non-human primates, a bivalent VLP vaccine targeting two distinct epitopes on PCSK9 elicited strong and durable antibody responses and lowered cholesterol levels. In macaques, a VLP vaccine targeting a single PCSK9 epitope was only effective at lowering LDL-C levels in combination with statins, whereas immunization with the bivalent vaccine lowered LDL-C without requiring statin co-administration. These data highlight the efficacy of an alternative, vaccine-based approach for lowering LDL-C. [ABSTRACT FROM AUTHOR]

Dyslipidemias have emerged as prevalent disorders among patients, posing significant risks for the development and progression of cardiovascular diseases. These conditions are characterized by elevated levels of total cholesterol (TC), triglycerides (TGs), and low-density lipoprotein cholesterol (LDL-C). This review delves into the current treatment approach, focusing on equalizing these parameters while enhancing the overall quality of life for patients. Through an extensive analysis of clinical trials, we identify disorders that necessitate alternative treatment strategies, notably familial hypercholesterolemia. The primary objective of this review is to consolidate existing information concerning drugs with the potential to revolutionize dyslipidemia management significantly. Among these promising pharmaceuticals, we highlight alirocumab, bempedoic acid, antisense oligonucleotides, angiopoietin-like protein inhibitors, apolipoprotein C-III (APOC3) inhibitors, lomitapide, and cholesterol ester transfer protein (CETP) inhibitors. Our review demonstrates the pivotal roles played by each of these drugs in targeting specific parameters of lipid metabolism. We outline the future landscape of dyslipidemia treatment, envisaging a more tailored and effective therapeutic approach to address this widespread medical concern. [ABSTRACT FROM AUTHOR]

High levels of plasma cholesterol, especially high levels of low-density lipoprotein cholesterol (LDL-C), have been associated with an increased risk of Alzheimer's disease. The cholesteryl ester transfer protein (CETP) in plasma distributes cholesteryl esters between lipoproteins and increases LDL-C in plasma. Epidemiologically, decreased CETP activity has been associated with sustained cognitive performance during aging, longevity, and a lower risk of Alzheimer's disease. Thus, pharmacological CETP inhibitors could be repurposed for the treatment of Alzheimer's disease as they are safe and effective at lowering CETP activity and LDL-C. Although CETP is mostly expressed by the liver and secreted into the bloodstream, it is also expressed by astrocytes in the brain. Therefore, it is important to determine whether CETP inhibitors can enter the brain. Here, we describe the pharmacokinetic parameters of the CETP inhibitor evacetrapib in the plasma, liver, and brain tissues of CETP transgenic mice. We show that evacetrapib crosses the blood-brain barrier and is detectable in brain tissue 0.5 h after a 40 mg/kg i.v. injection in a non-linear function. We conclude that evacetrapib may prove to be a good candidate to treat CETP-mediated cholesterol dysregulation in Alzheimer's disease. [ABSTRACT FROM AUTHOR]

A specific feature of dyslipidemia in pregnancy is increased high-density lipoprotein (HDL) cholesterol concentration, which is probably associated with maternal endothelium protection. However, preeclampsia is most often associated with low HDL cholesterol, and the mechanisms behind this change are scarcely explored. We aimed to investigate changes in HDL metabolism in risky pregnancies and those complicated by late-onset preeclampsia. We analyze cholesterol synthesis (cholesterol precursors: desmosterol, 7-dehydrocholesterol, and lathosterol) and absorption markers (phytosterols: campesterol and β-sitosterol) within HDL particles (NCSHDL), the activities of principal modulators of HDL cholesterol's content, and major HDL functional proteins levels in mid and late pregnancy. On the basis of the pregnancy outcome, participants were classified into the risk group (RG) (70 women) and the preeclampsia group (PG) (20 women). HDL cholesterol was lower in PG in the second trimester compared to RG (p < 0.05) and followed by lower levels of cholesterol absorption markers (p < 0.001 for campesterolHDL and p < 0.05 for β-sitosterolHDL). Lowering of HDL cholesterol between trimesters in RG (p < 0.05) was accompanied by a decrease in HDL phytosterol content (p < 0.001), apolipoprotein A-I (apoA-I) concentration (p < 0.05), and paraoxonase 1 (PON1) (p < 0.001), lecithin–cholesterol acyltransferase (LCAT) (p < 0.05), and cholesterol ester transfer protein (CETP) activities (p < 0.05). These longitudinal changes were absent in PG. Development of late-onset preeclampsia is preceded by the appearance of lower HDL cholesterol and NCSHDL in the second trimester. We propose that reduced capacity for intestinal HDL synthesis, decreased LCAT activity, and impaired capacity for HDL-mediated cholesterol efflux could be the contributing mechanisms resulting in lower HDL cholesterol. [ABSTRACT FROM AUTHOR]

Introduction: Cardiovascular disease (CVD) is a systemic multifocal illness called atherosclerosis that causes artery constriction and blockage. By causing cholesterol to build up in the artery wall, hypercholesterolemia is a major factor in the pathophysiology of atherosclerotic plaque development. Reverse cholesterol transport is the process of transporting cholesterol from the periphery back to the liver through cholesterol efflux mediated by high-density lipoprotein (HDL). It was suggested that the cholesterol efflux capacity (CEC), which is inversely linked with cardiovascular risk, can serve as a stand-in measure for reverse cholesterol transport. In this work, we sought to investigate a potential link between the peripheral plaque volume (PV) and CEC. Methods: Since lipid-lowering therapy interferes with CEC, we performed a cross-sectional study of 176 patients (48.9% females) with one cardiovascular risk factor or known CVD that did not currently take lipid-lowering medication. CEC was determined using cAMP-treated 3H-cholesterol-labeled J774 cells. Cholesterol ester transfer protein (CETP)-mediated cholesterol ester transfer was measured by quantifying the transfer of cholesterol ester from radiolabeled exogenous HDL cholesterol to Apolipoprotein B-containing lipoproteins. PV in the carotid and the femoral artery, defined as the total PV, was measured using a 3D ultrasound system equipped with semi-automatic software. Results: In our patients, we discovered an inverse relationship between high total PV and CEC (p = 0.027). However, there was no connection between total PV and low-density lipoprotein cholesterol, lipoprotein (a), or CETP-mediated cholesterol ester transfer. Conclusion: In patients not receiving lipid-lowering treatment, CEC inversely correlates with peripheral atherosclerosis, supporting its role in the pathophysiology of atherosclerosis. [ABSTRACT FROM AUTHOR]

Background: To investigate the association of HMGCR and NPC1L1 gene polymorphisms with residual cholesterol risk (RCR) in patients with premature triple-vessel disease (PTVD). Methods: Three SNPs within HMGCR including rs12916, rs2303151, and rs4629571, and four SNPs within NPC1L1 including rs11763759, rs4720470, rs2072183, and rs2073547 were genotyped. RCR was defined as achieved low-density lipoprotein cholesterol (LDL-C) concentrations after statins higher than 1.8 mmol/L (70 mg/dL). Results: Finally, a total of 609 PTVD patients treated with moderate-intensity statins were included who were divided into two groups: non-RCR group (n = 88) and RCR group (n = 521) according to LDL-C concentrations. Multivariate logistic regression showed the homozygotes for the minor allele of rs12916 within HMGCR gene (CC) were associated with a 2.08 times higher risk of RCR in recessive model [odds ratio (OR): 2.08, 95% confidence interval (CI): 1.16–3.75]. In codominant model, the individuals homozygous for the minor allele of rs12916 (CC) were associated with a 2.26 times higher risk of RCR (OR: 2.26, 95% CI: 1.16–4.43) while the heterozygous individuals (CT) were not, compared with the individuals homozygous for the major allele of rs12916 (TT). There was no significant association between the SNPs within NPC1L1 gene and RCR in various models. Conclusions: We first reported that the variant homozygous CC of rs12916 within HMGCR gene may incur a significantly higher risk of RCR in PTVD patients treated with statins, providing new insights into early individualized guidance of precise lipid-lowering treatment. [ABSTRACT FROM AUTHOR]

Despite many diabetic patients having hypercholesterolemia, the association of total cholesterol (TC) levels with CVD risk in type 2 diabetes (T2D) patients is unclear. Diagnosis of type 2 diabetes often leads to changes in total cholesterol (TC) levels. Thus, we examined whether changes in TC levels from pre- to post-diagnosis of T2D were associated with CVD risk. From the National Health Insurance Service Cohort, 23,821 individuals diagnosed with T2D from 2003 to 2012 were followed-up for non-fatal CVD incidence through 2015. Two measurements of TC, 2 years before and after T2D diagnosis, were classified into 3 levels (low, middle, high) to define changes in cholesterol levels. Cox proportional hazards regression was performed to estimate adjusted hazards ratios (aHRs) and 95% confidence intervals (CIs) for the associations between changes in cholesterol levels and CVD risk. Subgroup analyses were performed by use of lipid-lowering drugs. Compared with low–low, aHR of CVD was 1.31 [1.10–1.56] for low–middle and 1.80 [1.15–2.83] for low–high. Compared with middle–middle, aHR of CVD was 1.10 [0.92–1.31] for middle–high but 0.83 [0.73–0.94] for middle–low. Compared with high–high, aHR of CVD was 0.68 [0.56–0.83] for high–middle and 0.65 [0.49–0.86] for high–low. The associations were observed regardless of use of lipid-lowering drugs. For diabetic patients, management of TC levels may be important to lower CVD risk. [ABSTRACT FROM AUTHOR]

Background: Despite the superiority of non-HDL cholesterol (non-HDL-C) and apolipoprotein B (ApoB) as lipid markers for atherosclerotic cardiovascular disease (ASCVD), these are only suitable as secondary markers. We compared LDL cholesterol (LDL-C), non-HDLC, and ApoB concentrations with respect to the occurrence of cardiovascular disease in adults enrolled in the Korean Genome and Epidemiology Study (KoGES). Methods: We used information on age; sex; medical history; family history of ASCVD; current lipid-lowering therapy; current smoking status; and creatinine, total cholesterol, HDLC, LDL-C, triglyceride, and ApoB concentrations from 5,872 KoGES participants without ASCVD. New ASCVD development was monitored during the 8-year follow-up period. Adjusted hazard ratios (aHRs) for ASCVD of LDL-C, non-HDL-C, and ApoB concentrations were calculated based on the multivariate Cox regression analyses. The participants were also grouped as low and high according to the median values for each lipid marker, and calculated aHRs of each group combined by two lipid makers. Results: ApoB showed the highest aHR per 1-SD for ASCVD (1.26; 95% confidence interval [CI], 1.11-1.43), followed by non-HDL-C (1.25; 95% CI, 1.11-1.41) and LDL-C (1.20; 95% CI, 1.06-1.37). The group with low LDL-C and high ApoB concentrations had a significantly higher aHR for ASCVD (1.61; 95% CI, 1.05-2.48) compared to the reference group values (low LDL-C and low ApoB concentrations). The aHR for the group with high LDL-C and low ApoB concentrations was not significant (1.30; 95% CI, 0.79-2.16). Conclusions: ApoB, non-HDL-C, and LDL-C are independent risk factors for ASCVD. Increases in the aHR per 1-SD for ASCVD were more strongly affected by ApoB, followed by non-HDL-C and LDL-C. Participants with low LDL-C and high ApoB concentrations showed increased ASCVD risk. For individuals with ASCVD risk factors, even those presenting normal LDL-C concentrations, measuring ApoB concentrations can provide useful information for better evaluation of ASCVD risk. [ABSTRACT FROM AUTHOR]

Biomarkers are important tools to improve the early detection of patients at high risk for developing diabetes as well as the stratification of diabetic patients towards risks of complications. In addition to clinical variables, we analyzed 155 metabolic parameters in plasma samples of 51 healthy volunteers and 66 patients with diabetes using nuclear magnetic resonance (NMR) spectrometry. Upon elastic net analysis with lasso regression, we confirmed the independent associations of diabetes with branched-chain amino acids and lactate (both positive) as well as linoleic acid in plasma and HDL diameter (both inverse). In addition, we found the presence of diabetes independently associated with lower concentrations of free cholesterol in plasma but higher concentrations of free cholesterol in small HDL. Compared to plasmas of non-diabetic controls, plasmas of diabetic subjects contained lower absolute and relative concentrations of free cholesterol in all LDL and HDL subclasses except small HDL but higher absolute and relative concentrations of free cholesterol in all VLDL subclasses (except very small VLDL). These disbalances may reflect disturbances in the transfer of free cholesterol from VLDL to HDL during lipolysis and in the transfer of cell-derived cholesterol from small HDL via larger HDL to LDL. [ABSTRACT FROM AUTHOR]

HDL-mediated cholesterol efflux capacity (CEC) may protect from cardiovascular disease. Thus, we aimed to identify its genetic and non-genetic determinants. We measured CEC to 2% apolipoprotein B-depleted serum using BODIPY-cholesterol and cAMP-stimulated J774A.1 macrophages using serum samples from 4,981 participants in the German Chronic Kidney Disease (GCKD) study. Variance of CEC explained by clinical and biochemical parameters in a multivariable linear regression model was calculated by proportional marginal variance decomposition. A genome-wide association study with 7,746,917 variants was performed based on an additive genetic model. The main model was adjusted for age, sex and principal components 1-10. Further models were selected for sensitivity analysis and to reduce residual variance by known CEC pathways. Variables that explained 1% and more of the variance of CEC were concentrations of triglycerides (12.9%), HDL-cholesterol (11.8%), LDL-cholesterol (3.0%), apolipoprotein A-IV (2.8%), PCSK9 (1.0%), and eGFR (1.0%). The KLKB1 (chr4) and APOE/C1 (chr19) loci were genome-wide significantly (p < 5x10−8) associated with CEC in our main model (p = 8.8x10−10 and p = 3.3x10−10, respectively). KLKB1 remained significantly associated after additional adjustment for either kidney parameters, HDL-cholesterol, triglycerides or apolipoprotein A-IV concentrations, while the APOE/C1 locus was not significantly associated anymore after adjustment for triglycerides. Adjustment for triglycerides also revealed an association with the CLSTN2 locus (chr3; p = 6.0x10−9). We identified HDL-cholesterol and triglycerides as the main determinants of CEC. Furthermore, we newly found a significant association of CEC with the KLKB1 and the CLSTN2 locus and confirmed the association with the APOE/C1 locus, likely mediated by triglycerides. [Display omitted] • HDL-C and triglycerides are the main biochemical determinants of cholesterol efflux capacity each explaining >11% of variance. • In a GWAS, 2 novel genetic loci (KLKB1 & CLSTN2) and the known APOE/C1 locus are associated with cholesterol efflux capacity. • The KLKB1 locus is significant irrespective of adjustment for kidney function, HDL-C, triglycerides and apolipoprotein A-IV. • The association with the CLSTN2 locus is suggestive and reaches genome-wide significance with adjustment for triglycerides. [ABSTRACT FROM AUTHOR]

Cellular cholesterol can be metabolized to its fatty acid esters, cholesteryl esters (CEs), to be stored in lipid droplets (LDs). With triacylglycerols (TGs), CEs represent the main neutral lipids in LDs. However, while TG melts at ~4 °C, CE melts at ~44 °C, raising the question of how CE-rich LDs form in cells. Here, we show that CE forms supercooled droplets when the CE concentration in LDs is above 20% to TG and, in particular, liquid-crystalline phases when the fraction of CEs is above 90% at 37 °C. In model bilayers, CEs condense and nucleate droplets when the CE/phospholipid ratio reaches over 10-15%. This concentration is reduced by TG pre-clusters in the membrane that thereby facilitate CE nucleation. Accordingly, blocking TG synthesis in cells is sufficient to strongly dampen CE LD nucleation. Finally, CE LDs emerged at seipins, which cluster and nucleate TG LDs in the ER. However, when TG synthesis is inhibited, similar numbers of LDs are generated in the presence and absence of seipin, suggesting that seipin controls CE LD formation via its TG clustering capacity. Our data point to a unique model whereby TG pre-clusters, favorable at seipins, catalyze the nucleation of CE LDs. Dumesnil et al. report that cholesterol esters (CE), which only melt above body temperature, form supercooled liquid crystalline lipid droplets (LD). Triacylglycerols (TG) solubilize CE to help CE LD nucleation. Through clustering TGs in the ER membrane, seipin controls CE LD nucleation sites. [ABSTRACT FROM AUTHOR]

We report herein the synthesis of two non-ionic amphiphiles with a cholesterol hydrophobic moiety that can be used as chemical additives for biochemical studies of membrane proteins. They were designed to show a high similarity with the planar steroid core of cholesterol and small-to-medium polar head groups attached at the C3 position of ring-A on the sterol skeleton. The two Chol-Tris and Chol-DG have a Tris-hydroxymethyl and a branched diglucose polar head group, respectively, which provide them sufficient water solubility when mixed with the "gold standard" detergent n -Dodecyl-β-D-Maltoside (DDM). The colloidal properties of these mixed micelles were investigated by means of surface tension (SFT) measurements and dynamic light scattering (DLS) experiments and showed the formation of globular micelles of about 8 nm in diameter with a critical micellar concentration of 0.20 mM for DDM:Chol-DG and 0.22 mM for DDM:Chol-Tris. We showed that mixed micelles do not alter the extraction potency of a G-protein coupled receptor (GPCR): the human adenosine A2A receptor (A 2A R). The thermostabilizing effect of the mixed micelles was confirmed on two GPCRs, A 2A R and the growth hormone secretagogue receptor (GHSR). Finally, these two mixed micelles were found suitable for the purification of an active form of A 2A R which remained able to bind two ligands of different class i.e. the specific agonist CGS-21680 and the specific inverse agonist ZM-241385. This suggests that Chol-Tris and Chol-DG may be used as a non-ionic alternative to the cholesteryl hemisuccinate (CHS) stabilizing agent. [Display omitted] • Two non-ionic cholesterol-based amphiphiles were synthesized. • Mixed with DDM, they form micelles similar in size to those of pure DDM. • Mixed micelles led to thermostabilization of two GPCRs. • Mixed micelles allowed the purification of an active form of a GPCR. • These two derivatives are an alternative to the CHS stabilizing agent. [ABSTRACT FROM AUTHOR]

Although dyslipidemia in the brain has been implicated in neurodegenerative disorders, the molecular mechanisms underlying its pathogenesis have been largely unclear. PDZD8 is a lipid transfer protein and mice deficient in PDZD8 (PDZD8-KO mice) manifest abnormal accumulation of cholesteryl esters (CEs) in the brain due to impaired lipophagy, the degradation system of lipid droplets. Here we show the detailed mechanism of PDZD8-dependent lipophagy. PDZD8 transports cholesterol to lipid droplets (LDs), and eventually promotes fusion of LDs and lysosomes. In addition, PDZD8-KO mice exhibit growth retardation, hyperactivity, reduced anxiety and fear, increased sensorimotor gating, and impaired cued fear conditioned memory and working memory. These results indicate that abnormal CE accumulation in the brain caused by PDZD8 deficiency affects emotion, cognition and adaptive behavior, and that PDZD8 plays an important role in the maintenance of brain function through lipid metabolism. [ABSTRACT FROM AUTHOR]

Whilst dietary cholesterol guidelines have waivered through the years with historic restrictions lifted for the majority of the general population, recommendations to reduce saturated fat intake have been the mainstay of dietary guidelines since the 1980s and were recently reinforced by the Scientific Advisory Committee on Nutrition (SACN). Cholesterol metabolism is complex, with saturated fat known to have a more significant contribution at raising levels of low-density lipoprotein (LDL) cholesterol, a well-established risk factor for cardiovascular disease (CVD). However, it is clear from metabolic research that hyper-responsiveness to both dietary cholesterol and saturated fat exists; hence, for specific subsets of the population, reductions in both nutrients may be indicated. With this in mind, the current article aims to provide an overview of the mechanisms underlying biological variation in responsiveness and introduces research currently underway which will hopefully identify simple biomarkers that can be used to predict responsiveness and permit tailored, personalised, dietary advice. Eggs are a well-known source of dietary cholesterol whilst being low in saturated fat. A common question encountered in clinical practice is must individuals limit intake to manage blood cholesterol levels. This article summarises key recent papers which confirm that eggs can be enjoyed as part of a healthy balanced diet, whilst highlighting the need for further research in certain population groups, e.g. in individuals with diabetes. [ABSTRACT FROM AUTHOR]

The milk thistle (Silybum marianum (Sm)) is a medicinal plant used for a long time in the Algerian traditional medicine. its cardioprotective and preventive effects against the development of obesity complications have been very little investigated. The aim of this study was to see if milk thistle seed can slow down the onset of cardio-metabolic disorders in rats prematurely exposed to a High Lipid/High Sugar (HL/HS) diet. Thirty male Wistar rats are divided into three homogeneous groups. The first Control group (C) receives a normocaloric diet; the second consumes the HL/HS diet (untreated group) and the third treated group was exposed to the HL/HS diet supplemented with 10 g/day of Sm seeds (HL/HS-Sm group). After 1 month of experimentation, a reduction in body weight (-14%), enzymatic activities of aspartate aminotransferase (-37%) and alanine aminotransferase (-33%), total lipids, total cholesterol (-58%), unesterified cholesterol (-56%) and cholesteryl esters (-38%) was noted in HL/HS-Sm group compared to HL/HS. Sm seed also reduces blood glucose (1.3-fold), HbA1c (2-fold) as well as CRP, albumin and lactate dehydrogenase (LDH) activity (-32%, -20%, -24%). In contrast, the cholesterol content of anti-atherogenic lipoproteins, the activity of lecithin: cholesterol acyltransferase and the antioxidant capacity (CAox) were high (+36%; +42%; +10%). In conclusion, Sm seeds in an HL/HS diet have a hypolipidemic effect by improving the antiatherogenic pathway, reduce liver disorders and decrease inflammation and lipoperoxidation by strengthening CAox preventing the development of obesity and the progression of fatty liver disease and its complications. [ABSTRACT FROM AUTHOR]

Worldwide, cardiovascular disease is considered a major cause of death and disability. Age, sex, blood pressure, total cholesterol, high-density lipoprotein cholesterol, smoking and diabetes contribute in the development of the disease. Hence, high-density lipoprotein cholesterol modulation using cholesteryl ester transfer protein inhibitors could have a great role in reducing cardiovascular disease risk and mortality. In this work, ten new benzyloxalamides 8a-j were synthesized and characterized targeting the cholesteryl ester transfer protein inhibition. Biological study results showed that compound 8f had the greatest activity with a percentage inhibition of 64.1 at a concentration of 10 µM and an half-maximal inhibitory concentration of 2.1 µM. Functional moieties of 8a-j matched the cholesteryl ester transfer protein inhibitors pharmacophoric features; mainly the aromatic and hydrophobic ones. Moreover, Glide docking revealed that the targeted compounds lodge the binding site of cholesteryl ester transfer protein and are surrounded by hydrophobic liner. Benzyloxalamides can serve as lead scaffold for the development of cholesteryl ester transfer protein inhibitors. [ABSTRACT FROM AUTHOR]

• EPA and DHA lowered plasma TG concentrations. • Changes in TG concentrations were inversely associated with changes in LPL activity. • DHA increased LDL-C concentrations. • EPA and DHA plasma lipid changes varied by sex. Eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) have been shown to similarly lower plasma TG concentrations but differentially regulate plasma LDL-C and HDL-C concentrations. The aim of this study was to evaluate the common and differential effects of these ω-3 fatty acids on plasma lipids and lipoproteins and to assess the metabolic mechanisms of the effects. In a randomized, double-blind, crossover study, we assessed the effect of 10-week supplementation with 3 g/d pure EPA and pure DHA (both as ethyl ester, ≥97% purity) on plasma lipid and lipoprotein concentrations and activities of lipoprotein lipase (LPL), cholesteryl ester transfer protein (CETP) and lecithin:cholesterol acyl transferase (LCAT) in 21 older (>50 y) men and postmenopausal women with some characteristics of metabolic syndrome and low-grade chronic inflammation. Both EPA and DHA lowered plasma TG concentrations and increased LDL-C/apoB and HDL-C/apoA-I ratios, but only DHA increased LDL-C concentrations. The reductions in plasma TG were inversely associated with the changes in LPL activity after both EPA and DHA supplementation. EPA lowered CETP, while DHA lowered LCAT activity. EPA and DHA worked differently in men and women, with DHA increasing LPL activity and LDL-C concentrations in women, but not in men. EPA and DHA exerted similar effects on plasma TG, but differences were observed in LDL-C concentrations and activities of some enzymes involved in lipoprotein metabolism. It was also noted that EPA and DHA worked differently in men and women, supporting sex-specific variations in lipoprotein metabolism. [ABSTRACT FROM AUTHOR]

Excess cholesterol storage can induce the formation of cholesterol crystals in hepatocyte lipid droplets. Such crystals distinguish metabolic dysfunction associated steatohepatitis (MASH) from simple steatosis and may underlie its pathogenesis by causing cell damage that triggers liver inflammation. The mechanism linking cholesterol excess to its crystallization in lipid droplets is unclear. As cholesteryl esters localize to and accumulate in lipid droplets more readily than unesterified free cholesterol, we investigated whether cholesterol esterification by sterol O-acyltransferase (SOAT), also known as acyl co-A cholesterol acyltransferase (ACAT), is required for hepatocyte lipid droplet crystal formation. Cholesterol crystals were measured in cholesterol loaded Hep3B hepatocytes, RAW264.7 macrophages, and mouse liver using polarizing light microscopy. We examined the effect of blocking SOAT activity on crystal formation and compared these results to features of cholesterol metabolism and the progression to intracellular crystal deposits. Cholesterol loading of Hep3B cells caused robust levels of lipid droplet localized crystal formation in a dose- and time-dependent manner. Co-treatment with SOAT inhibitors and genetic ablation of SOAT1 blocked crystal formation. SOAT inhibitor also blocked crystal formation in low density lipoprotein (LDL) treated Hep3B cells, acetylated LDL treated RAW 264.7 macrophages, and in the liver of mice genetically predisposed to hepatic cholesterol overload and in mice with cholesterol enriched diet-induced MASH. SOAT1-mediated esterification may underlie cholesterol crystals associated with MASH by concentrating it in lipid droplets. These findings imply that inhibiting hepatocyte SOAT1 may be able to alleviate cholesterol associated MASH. Moreover, that either a lipid droplet localized cholesteryl ester hydrolase is required for cholesterol crystal formation, or the crystals are composed of cholesteryl ester. • Cholesterol overload induces cholesterol crystals in Hep3B hepatocytes. • Induced crystals are lipid droplet localized and can form lattice structures. • Cholesterol esterification via SOAT/ACAT activity mediates crystal formation. • SOAT-dependent crystals form in cultured RAW264.7 macrophage. • SOAT-dependent crystals form in mouse liver during MASH. [ABSTRACT FROM AUTHOR]

Background: The etiopathogenesis of abdominal aortic aneurysm (AAA) is still unclarified, but vascular inflammation and matrix metalloproteases activation have a recognized role in AAA development and progression. Circulating lipoproteins are involved in tissue inflammation and repair, particularly through the regulation of intracellular cholesterol, whose excess is associated to cell damage and proinflammatory activation. We analyzed lipoprotein metabolism and function in AAA and in control vasculopathic patients, to highlight possible non-atherosclerosis-related, specific abnormalities. Methods: We measured fluorometrically serum esterified/total cholesterol ratio, as an index of lecithin-cholesterol acyltransferase (LCAT) activity, and cholesteryl ester transfer protein (CETP) activity in patients referred to vascular surgery either for AAA (n=30) or stenotic aortic/peripheral atherosclerosis (n=21) having similar burden of cardiovascular risk factors and disease. We measured high-density lipoprotein (HDL)-cholesterol efflux capacity (CEC), through the ATP-binding cassette G1 (ABCG1) and A1 (ABCA1) pathways and serum cell cholesterol loading capacity (CLC), by radioisotopic and fluorimetric methods, respectively. Results: We found higher LCAT (+23%; p < 0.0001) and CETP (+49%; p < 0.0001) activity in AAA sera. HDL ABCG1-CEC was lower (-16%; p < 0.001) and ABCA1-CEC was higher (+31.7%; p < 0.0001) in AAA. Stratification suggests that smoking may partly contribute to these modifications. CEC and CETP activity correlated with CLC only in AAA. Conclusions: We demonstrated that compared to patients with stenotic atherosclerosis, patients with AAA had altered HDL metabolism and functions involved in their anti-inflammatory and tissue repair activity, particularly through the ABCG1-related intracellular signaling. Clarifying the relevance of this mechanism for AAA evolution might help in developing new diagnostic parameters and therapeutic targets for the early management of this condition. [ABSTRACT FROM AUTHOR]

Plasma cholesteryl ester transfer protein (CETP) activity diminishes HDL-cholesterol levels and thus may increase atherosclerosis risk. Experimental evidence suggests CETP may also exhibit anti-inflammatory properties, but local tissue-specific functions of CETP have not yet been clarified. Since oxidative stress and inflammation are major features of atherogenesis, we investigated whether CETP modulates macrophage oxidant production, inflammatory and metabolic profiles. Comparing macrophages from CETP-expressing transgenic mice and non-expressing littermates, we observed that CETP expression reduced mitochondrial superoxide anion production and H2O2 release, increased maximal mitochondrial respiration rates, and induced elongation of the mitochondrial network and expression of fusion-related genes (mitofusin-2 and OPA1). The expression of pro-inflammatory genes and phagocytic activity were diminished in CETP-expressing macrophages. In addition, CETP-expressing macrophages had less unesterified cholesterol under basal conditions and after exposure to oxidized LDL, as well as increased HDL-mediated cholesterol efflux. CETP knockdown in human THP1 cells increased unesterified cholesterol and abolished the effects on mitofusin-2 and TNFα. In summary, the expression of CETP in macrophages modulates mitochondrial structure and function to promote an intracellular antioxidant state and oxidative metabolism, attenuation of pro-inflammatory gene expression, reduced cholesterol accumulation, and phagocytosis. These localized functions of CETP may be relevant for the prevention of atherosclerosis and other inflammatory diseases. [ABSTRACT FROM AUTHOR]

Due to the widespread unorthodox use of nuts to improve cardiovascular health, this clinical trial was carried out to evaluate the efficacy of walnut as an adjuvant statin in hypertensive subjects. A single-blind placebo-controlled randomized clinical trial that lasted for 3 months. Forty-five screened hypertensive subjects on treatment, aged 45–65 years, were randomized into intervention and placebo groups according to their blood pressure defined by the American Heart Association criteria. Fifteen (15) normotensive subjects were also recruited for this study. The participants in the intervention group included daily 7 g of boiled walnut taken as snacks. The study was not controlled for type of diet and frequency of meals in a day. Low-density lipoprotein cholesterol (LDLc) was the primary endpoint for this study. The mean LDLc levels of the intervention groups (84.6 mg/dl and 79.7 mg/dl, respectively) were significantly (p <.005) lower than the placebo (137.6 mg/dl). The high-density lipoprotein cholesterol (HDLc) levels of the intervention groups were significantly higher than the placebo. The mean total cholesterol levels of the intervention groups were significantly lower than the placebo group. The intervention groups recorded a significantly lower systolic and diastolic blood pressure compared to the placebo. The supplementation of walnut significantly decreased the apolipoprotein E (APOE), proprotein convertase subtilisin kexin 9 (PCSK9), and cholesteryl ester transfer protein (CETP) activities relative to the placebo. The use of walnut as a statin adjuvant during hypertension treatment reduced LDLc levels within 42.1% and improved HDL levels by 33.6%, and the LDLc decrease related to reduced PCSK9 and APOE activities while the HDLc increase related to reduced CETP activities. [ABSTRACT FROM AUTHOR]

As opposed to adults, high-density lipoprotein (HDL) is the main cholesterol carrying lipoprotein in fetal circulation. The major HDL receptor, scavenger receptor class B type I (SR-BI), contributes to local cholesterol homeostasis. Arterial endothelial cells (ECA) from human placenta are enriched with cholesterol compared to venous endothelial cells (ECV). Moreover, umbilical venous and arterial plasma cholesterol levels differ markedly. We tested the hypothesis that the uptake of HDL-cholesteryl esters differs between ECA and ECV because of the differential expression of SR-BI. We aimed to identify the key regulators underlying these differences and the functional consequences. Immunohistochemistry was used for visualization of SR-BI in situ. ECA and ECV were isolated from the chorionic plate of human placenta and used for RT-qPCR, Western Blot, and HDL uptake assays with 3H- and 125I-labeled HDL. DNA was extracted for the methylation profiling of the SR-BI promoter. SR-BI regulation was studied by exposing ECA and ECV to differential oxygen concentrations or shear stress. Our results show elevated SR-BI expression and protein abundance in ECA compared to ECV in situ and in vitro. Immunohistochemistry demonstrated that SR-BI is mainly expressed on the apical side of placental endothelial cells in situ, allowing interaction with mature HDL circulating in the fetal blood. This was functionally linked to a higher increase of selective cholesterol ester uptake from fetal HDL in ECA than in ECV, and resulted in increased cholesterol availability in ECA. SR-BI expression on ECV tended to decrease with shear stress, which, together with heterogeneous immunostaining, suggests that SR-BI expression is locally regulated in the placental vasculature. In addition, hypomethylation of several CpG sites within the SR-BI promoter region might contribute to differential expression of SR-BI between chorionic arteries and veins. Therefore, SR-BI contributes to a local cholesterol homeostasis in ECA and ECV of the human feto-placental vasculature. [ABSTRACT FROM AUTHOR]