Experimental models for the investigation of high-density lipoprotein-mediated cholesterol efflux

Procoagulant phenotype induced by oxidized high-density lipoprotein associates with acute kidney injury and death

BACKGROUND

Oxidative stress derived from severe systemic inflammation promotes conversion from high-density lipoprotein HDL to oxidized HDL (oxHDL), which interacts with vascular endothelial cells (ECs). OxHDL acquires procoagulant features playing a role in modulating coagulation, which has been linked with organ failure in ICU patients. However, whether oxHDL elicits a ECs-mediated procoagulant phenotype generating organ failure and death, and the underlying molecular mechanism is not known. Therefore, we studied whether oxHDL-treated rats and high-oxHDL ICU patients exhibit a procoagulant phenotype and its association with kidney injury and mortality and the endothelial underlying molecular mechanism.

METHODS

Human ECs, oxHDL-treated rats and ICU patients were subjected to several cellular and molecular studies, coagulation analyses, kidney injury assessment and mortality determination.

RESULTS

OxHDL-treated ECs showed a procoagulant protein expression reprograming characterized by increased E-/P-selectin and vWF mRNA expression through specific signaling pathways. OxHDL-treated rats exhibited a procoagulant phenotype and modified E-/P-selectin, vWF, TF and t-PA mRNA expression correlating with plasma TF, t-PA and D-dimer. Also, showed increased death events and the relative risk of death, and increased creatinine, urea, BUN/creatinine ratio, KIM-1, NGAL, β2M, and decreased eGFR, all concordant with kidney injury, correlated with plasma TF, t-PA and D-dimer. ICU patients showed correlation between plasma oxHDL and increased creatinine, cystatin, BUN, BUN/creatinine ratio, KIM-1, NGAL, β2M, and decreased GFR. Notably, ICU high-oxHDL patients showed decreased survival. Interestingly, altered coagulation factors TF, t-PA and D-dimer correlated with both increased oxHDL levels and kidney injury markers, indicating a connection between these factors.

CONCLUSION

Increased circulating oxHDL generates an endothelial-dependent procoagulant phenotype that associates with acute kidney injury and increased risk of death.

Non-HDL-C/HDL-C ratio is associated with carotid plaque stability in general population: A cross-sectional study

Background

Carotid atherosclerosis, especially the rupture of unstable plaques, plays an important role in the development of stroke. A novel lipid ratio, the non-high-density lipoprotein cholesterol (non-HDL-C)/high-density lipoprotein cholesterol (HDL-C) ratio, contains both atherogenic and anti-atherogenic particle information, and has been shown to be associated with carotid atherosclerosis. However, there is no data on evaluating the association between non-HDL-C/HDL-C ratio and carotid plaque stability.

Methods

This study was carried out on 27,436 urban workers aged 20 years or older who participated in a comprehensive health screening between January 2016 and December 2017. Carotid plaque stability was assessed using ultrasonography. Multinomial logistic regression models were used to explore the relationship between the non-HDL-C/HDL-C ratio and carotid plaque stability by odds ratios (ORs) and 95% confidence intervals (CIs). Subgroup and sensitivity analyses were performed to verify the robustness of the results.

Results

Carotid plaque was detected in 7,161 (26.1%) participants, with stable and unstable plaque accounting for 3,277 (11.9%) and 3,884 (14.2%), respectively. The prevalence of stable carotid plaque substantially increased with increasing non-HDL-C/HDL-C ratio quartile levels (p for trend < 0.001) and with a similar association for unstable carotid plaque (p for trend < 0.001). The mean non-HDL-C/HDL-C ratios (mean ± SD) of non-carotid plaque (2.9 ± 1.1), stable carotid plaque (3.2 ± 1.2), and unstable carotid plaque (3.4 ± 1.4) gradually increased (p < 0.001). In multinomial logistic regression, ORs (95% CIs) for the highest vs. lowest quartile of the non-HDL-C/HDL-C ratio were 1.70 (1.48–1.95) between stable carotid plaques and no carotid plaque, 2.34 (2.06–2.67) between unstable carotid plaques and no carotid plaque, and 1.38 (1.18–1.61) between unstable carotid plaques and stable carotid plaque, after adjusting for common cardiovascular risk factors. The results of subgroup analysis and sensitivity analysis were similar.

Conclusion

Our findings suggested that the non-HDL-C/HDL-C ratio was significantly associated with carotid plaque stability and might be a useful indicator for the early identification of high-risk carotid plaque.

Serum Levels of Cholesterol and Lipoproteins in Patients With Symptomatic Paravalvular Leaks

Paravalvular leak (PVL) is a complication of valve replacement surgery which may lead to serious clinical consequences including hemolytic anemia. This study aimed to retrospectively evaluate the effect of successful intervention on serum lipid parameters in patients with PVL. A total of 106 patients (mean age: 57.2 ± 13.6 years, male: 67) who underwent surgical or transcatheter closure for symptomatic PVL were enrolled in this study. During the follow-up period, hemolysis and lipid parameters were evaluated at each clinical visit. This is the first study describing the effects of PVL on lipid metabolism after surgical or transcatheter closure. In the study, 18 patients (17%) had aortic PVL, 84 patients (79%) had mitral PVL, and 4 patients (3.8%) had both aortic and mitral PVL. A total of 59 patients underwent transcatheter closure and 47 patients were treated surgically. Technical success of the procedures was 83%. After successful PVL closure, hemoglobin and haptoglobin levels increased significantly (9.5 ± 1.3 vs 11.9 ± 2.1 g/dl, p <0.001 and 16.6 ± 7.9 vs 34.1 ± 19.9 mg, p <0.001, respectively). A significant increase in total cholesterol (158.9 ± 42.7 vs 209.3 ± 58.7 mg/dl, p <0.001), low-density lipoprotein cholesterol (99.1 ± 33.8 vs 133.9 ± 45.7 mg/dl, p <0.001), and high-density lipoprotein cholesterol (39.8 ± 12.4 vs 44.8 ± 11.7 mg/dl, p <0.001) levels was observed after successful PVL closure. In conclusion, symptomatic patients with PVL had hypocholesterolemia, reflected by low serum lipoprotein levels. After successful PVL closure, an increase in serum lipoprotein levels was observed. The recovery in levels of lipoproteins could be used as a marker of successful PVL closure, and absence of recovery of lipoprotein levels may indicate incomplete closure.

Simultaneous Noninvasive Detection and Therapy of Atherosclerosis Using HDL Coated Gold Nanorods

Cardiovascular disease (CVD) is a major cause of death and disability worldwide. A real need exists in the development of new, improved therapeutic methods for treating CVD, while major advances in nanotechnology have opened new avenues in this field. In this paper, we report the use of gold nanoparticles (GNPs) coated with high-density lipoprotein (HDL) (GNP-HDL) for the simultaneous detection and therapy of unstable plaques. Based on the well-known HDL cardiovascular protection, by promoting the reverse cholesterol transport (RCT), injured rat carotids, as a model for unstable plaques, were injected with the GNP-HDL. Noninvasive detection of the plaques 24 h post the GNP injection was enabled using the diffusion reflection (DR) method, indicating that the GNP-HDL particles had accumulated in the injured site. Pathology and noninvasive CT measurements proved the recovery of the injured artery treated with the GNP-HDL. The DR of the GNP-HDL presented a simple and highly sensitive method at a low cost, resulting in simultaneous specific unstable plaque diagnosis and recovery.

Fat-1 expression alleviates atherosclerosis in transgenic rabbits

Atherosclerosis is the main cause of cardiovascular diseases. The Fat-1 gene can express the n-3 fatty acid desaturase, which converts n-6 polyunsaturated fatty acids (PUFA) to n-3 PUFAs. The role of n-3 PUFAs in atherosclerosis is widely debated. This study explored the effect of n-3 PUFAs on atherosclerosis in rabbits. In this study, atherosclerosis was induced in Fat-1 transgenic rabbits and their littermate (WT) rabbits by feeding a high-cholesterol diet containing 0.3% cholesterol and 3% soybean oil for 16 weeks. Plasma lipid, fatty acid and pathological analyses of atherosclerotic lesions were conducted. Fatty acid composition in the liver and muscle showed that n-3 PUFAs increased and n-6 PUFAs decreased in the Fat-1 group. Plasma high-density lipoprotein cholesterol (HDL-C) levels were significantly increased in the Fat-1 group, and the atherosclerotic lesion area of the aortic arch in Fat-1 transgenic rabbits was significantly reduced. Histological analysis showed that smooth muscle cells (SMCs) in atherosclerotic lesions decreased significantly. In conclusion, n-3 PUFAs improve atherosclerosis in Fat-1 transgenic rabbits, and this process may depend on the increase in plasma HDL-C and the decrease in the amount of SMCs in atherosclerotic plaques.

Impact of Dietary Lipids on the Reverse Cholesterol Transport: What We Learned from Animal Studies

Reverse cholesterol transport (RCT) is a physiological mechanism protecting cells from an excessive accumulation of cholesterol. When this process begins in vascular macrophages, it acquires antiatherogenic properties, as has been widely demonstrated in animal models. Dietary lipids, despite representing a fundamental source of energy and exerting multiple biological functions, may induce detrimental effects on cardiovascular health. In the present review we summarize the current knowledge on the mechanisms of action of the most relevant classes of dietary lipids, such as fatty acids, sterols and liposoluble vitamins, with effects on different steps of RCT. We also provide a critical analysis of data obtained from experimental models which can serve as a valuable tool to clarify the effects of dietary lipids on cardiovascular disease.

A Ketogenic Low-Carbohydrate High-Fat Diet Increases LDL Cholesterol in Healthy, Young, Normal-Weight Women: A Randomized Controlled Feeding Trial

Ketogenic low-carbohydrate high-fat (LCHF) diets are popular among young, healthy, normal-weight individuals for various reasons. We aimed to investigate the effect of a ketogenic LCHF diet on low-density lipoprotein (LDL) cholesterol (primary outcome), LDL cholesterol subfractions and conventional cardiovascular risk factors in the blood of healthy, young, and normal-weight women. The study was a randomized, controlled, feeding trial with crossover design. Twenty-four women were assigned to a 4 week ketogenic LCHF diet (4% carbohydrates; 77% fat; 19% protein) followed by a 4 week National Food Agency recommended control diet (44% carbohydrates; 33% fat; 19% protein), or the reverse sequence due to the crossover design. Treatment periods were separated by a 15 week washout period. Seventeen women completed the study and treatment effects were evaluated using mixed models. The LCHF diet increased LDL cholesterol in every woman with a treatment effect of 1.82 mM (p < 0.001). In addition, Apolipoprotein B-100 (ApoB), small, dense LDL cholesterol as well as large, buoyant LDL cholesterol increased (p < 0.001, p < 0.01, and p < 0.001, respectively). The data suggest that feeding healthy, young, normal-weight women a ketogenic LCHF diet induces a deleterious blood lipid profile. The elevated LDL cholesterol should be a cause for concern in young, healthy, normal-weight women following this kind of LCHF diet.

Berberine Attenuates Cholesterol Accumulation in Macrophage Foam Cells by Suppressing AP-1 Activity and Activation of the Nrf2/HO-1 Pathway

Atherosclerosis is a chronic inflammation condition resulting from the interaction between lipoproteins, monocyte-derived macrophages, T lymphocytes, and other cellular elements in the arterial wall. Macrophage-derived foam cells play a key role in both early and advanced stage of atherosclerosis. Previous studies have shown that berberine could inhibit foam cell formation and prevent experimental atherosclerosis. However, its underlying molecular mechanisms have not been fully clarified. In this study, we explored the cholesterol-lowering effects of berberine in macrophage-derived foam cells and investigated its possible mechanisms in prevention and treatment of atherosclerosis. Here, we demonstrated that berberine could inhibit atherosclerosis in apolipoprotein E-deficient mice and induce cholesterol reduction as well as decrease the content of macrophages. Berberine can regulate oxLDL uptake and cholesterol efflux, thus suppresses foam cell formation. Mechanisms study showed that berberine can suppress scavenger receptor expression via inhibiting the activity of AP-1 and upregulate ATP-binding cassette transporter via activating Nrf2/HO-1 signaling in human macrophage. In summary, berberine significantly inhibits atherosclerotic disease development by regulating lipid homeostasis and suppressing macrophage foam cell formation.

Relationship Between HDL Functional Characteristics and Cardiovascular Health and Potential Impact of Dietary Patterns: A Narrative Review

Cardiovascular disease is a leading cause of death around the world. Overall diet quality and dietary behaviors are core contributors to metabolic health. While therapeutic targets have traditionally focused on levels of lipoprotein cholesterol when evaluating cardiovascular risk, current perspectives on high-density lipoprotein (HDL) have shifted to evaluating the functionality of this lipoprotein particle. Effects of diet on cardiovascular health are mediated through multiple pathways, but the impact on HDL composition and function deserves greater attention. Potential areas of investigation involve changes in particle characteristics, distribution, microRNA cargo, and other functional changes such as improvements to cholesterol efflux capacity. Various dietary patterns like the Mediterranean diet and Dietary Approaches to Stop Hypertension (DASH) diet have beneficial effects on cardiovascular health and may prevent cardiovascular events. These healthful dietary patterns tend to be rich in plant-based foods, with cardiovascular benefits likely resulting from synergistic effects of the individual dietary components. The purpose of this review is to summarize current perspectives on selected functions of HDL particles and how various dietary patterns affect cardiovascular health biomarkers, with a focus on HDL functionality.

Evacetrapib reduces preβ-1 HDL in patients with atherosclerotic cardiovascular disease or diabetes

BACKGROUND AND AIMS

Cholesteryl ester transfer protein (CETP) inhibitor-mediated induction of HDL-cholesterol has no effect on the protection from cardiovascular disease (CVD). However, the mechanism is still unknown. Data on the effects of this class of drugs on subclasses of HDL are either limited or insufficient. In this study, we investigated the effect of evacetrapib, a CETP inhibitor, on subclasses of HDL in patients with atherosclerotic cardiovascular disease or diabetes.

METHODS

Baseline and 3-month post-treatment samples from atorvastatin 40 mg plus evacetrapib 130 mg (n = 70) and atorvastatin 40 mg plus placebo (n = 30) arms were used for this purpose. Four subclasses of HDL (large HDL, medium HDL, small HDL, and preβ-1 HDL) were separated according to their size and quantified by densitometry using a recently developed native polyacrylamide gel electrophoresis (PAGE) system.

RESULTS

Relative to placebo, while evacetrapib treatment dramatically increased large HDL and medium HDL subclasses, it significantly reduced small HDL (27%) as well as preβ-1 HDL (36%) particles. Evacetrapib treatment reduced total LDL, but also resulted in polydisperse LDL with LDL particles larger and smaller than the LDL subclasses of the placebo group.

CONCLUSION

Evacetrapib reduced preβ-1 HDL and small HDL in patients with ASCVD or diabetes on statin. Preβ-1 HDL and medium HDL are negatively interrelated. The results could give a clue to understand the effect of CETP inhibitors on cardiovascular outcomes.

High-Density Lipoprotein Functionality as a New Pharmacological Target on Cardiovascular Disease: Unifying Mechanism That Explains High-Density Lipoprotein Protection Toward the Progression of Atherosclerosis

The formation of the atherosclerotic plaque that is characterized by the accumulation of abnormal amounts of cholesterol-loaded macrophages in the artery wall is mediated by both inflammatory events and alterations of lipid/lipoprotein metabolism. Reverse transport of cholesterol opposes the formation and development of atherosclerotic plaque by promoting high density lipoprotein (HDL)-mediated removal of cholesterol from peripheral macrophages and its delivery back to the liver for excretion into the bile. Although an inverse association between HDL plasma levels and the risk of cardiovascular disease (CVD) has been demonstrated over the years, several studies have recently shown that the antiatherogenic functions of HDL seem to be mediated by their functionality, not always associated with their plasma concentrations. Therefore, assessment of HDL function, evaluated as the capacity to promote cell cholesterol efflux, may offer a better prediction of CVD than HDL levels alone. In agreement with this idea, it has recently been shown that the assessment of serum cholesterol efflux capacity (CEC), as a metric of HDL functionality, may represent a predictor of atherosclerosis extent in humans. The purpose of this narrative review is to summarize the current evidence concerning the role of cholesterol efflux capacity that is important for evaluating CVD risk, focusing on pharmacological evidences and its relationship with inflammation. We conclude that HDL therapeutics are a promising area of investigation but strategies for identifying efficacy must move beyond the idea of simply raising static HDL-cholesterol levels and toward methods of measuring the dynamics of HDL particle remodeling and the generation of lipid-free apolipoprotein A-I (apoA-I). In this way, apoA-I, unlike mature HDL, can promote the greatest extent of cholesterol efflux relieving cellular cholesterol toxicity and the inflammation it causes.

Anti-Atherosclerotic Effect of a Polyphenol-Rich Ingredient, Oleactiv®, in a Hypercholesterolemia-Induced Golden Syrian Hamster Model

The development of nutraceutical ingredients has risen as a nutritional solution for health prevention. This study evaluated the effects of Oleactiv®, an ingredient developed for the prevention of atherogenesis, in hypercholesterolemic hamsters. Oleactiv® is a polyphenol-rich ingredient obtained from artichoke, olive and grape extracts as part of fruit and vegetables commonly consumed within the Mediterranean diet. A total of 21 Golden Syrian hamsters were divided into three groups. The standard group (STD) was fed a normolipidemic diet for 12 weeks, while the control group (CTRL) and Oleactiv® goup (OLE) were fed a high-fat diet. After sacrifice, the aortic fatty streak area (AFSA), plasmatic total cholesterol (TC), high-density lipoproteins (HDL-C), non-HDL-C and triglycerides (TG), were assessed. The cholesterol efflux capacity (CEC) of hamster plasma was quantified using a radiolabeled technique in murine macrophages J774. OLE administration induced a significant reduction of AFSA (-69%, p < 0.0001). Hamsters of the OLE group showed a significant decrease of both non-HDL-C (-173 mmol/L, p < 0.05) and TG (-154 mmol/L, p < 0.05). Interestingly, OLE induced a significant increase of total CEC (+17,33%, p < 0,05). Oleactiv® supplementation prevented atheroma development and had positive effects on the lipid profile of hypercholesterolemic hamsters. The increased CEC underlines the anti-atherosclerotic mechanism at the root of the atheroma reduction observed.

Correlation of Paraoxonase-1 with the Severity of Crohn's Disease

Diagnostics of Crohn’s disease (CD) requires noninvasive biomarkers facilitating early detection and differentiation of the disease. Therefore, in this study, we aimed to determine the relationship between paraoxonase-1 (PON-1), the severity of CD, oxidative stress, and inflammation in CD. The CD activity index was based on the current classification. Plasma PON-1 was measured in 47 patients with CD, and in 23 control volunteers. Using quantitative variables such as receiver operating characteristics (ROC) (area under the curve (AUC)), the diagnostic utility of PON-1 in differentiating the severity of CD was assessed. Circulating PON-1 was found to be decreased in the CD group compared to the control group (269.89 vs. 402.56 U/L, respectively), and it correlated well with the disease activity. PON-1 correlated positively with hemoglobin (Hb) (r = 0.539, p < 0.001), hematocrit (Ht) (r = 0.48, p < 0.001), total cholesterol (TC) (r = 0.343, p < 0.001), high density lipoprotein (HDL) (r = 0.536, p < 0.001), low density lipoprotein (LDL) (r = 0.54, p < 0.001), and triglyceride (TG) (r = 0.561, p < 0.001) and correlated negatively with white blood cell count (WBC) (r = −0.262, p = 0.029), platelet count (PLT) (r = −0.326, p = 0.006), C-reactive protein (CRP) (r = −0.61, p < 0.001), and malondialdehyde (MDA) (r = −0.924, p < 0.001). PON-1 as a marker for CD differentiation possessed a sensitivity and specificity of 93.62% and 91.30%, respectively. CD was found to be associated with the decrease in the levels of PON-1, which correlates well with activity of the disease and reflects the intensification of inflammation, as well as intensified lipid peroxidation. High sensitivity and specificity of PON-1 determines its selection as a good screening test for CD severity.

T2 mapping MRI technique quantifies carotid plaque lipid, and its depletion after statin initiation, following acute myocardial infarction

BACKGROUND & AIMS

A recently-validated, highly-sensitive T2 mapping magnetic resonance (MRI) technique accurately quantifies carotid plaque lipid. The aims of this study were to determine: (i) the extent of carotid plaque lipid in patients with acute coronary syndromes (ACS); (ii) the effects of initiation of high-intensity statin on plaque lipid content and (iii) whether plaque lipid content is related to standard or 'functional' blood lipid measurements.

METHODS

Statin naïve subjects presenting with ACS underwent carotid artery MRI at 3 T scanner to quantify plaque lipid. Patients were subsequently commenced on high dose statin as part of clinical care and underwent a second MRI after three months. Plaque composition was measured using objective semi-automated techniques.

RESULTS

23 out of 24 patients had measurable lipid. Three months after statin initiation there was a significant reduction in carotid lipid percentage [from 10.3% (7.2-14.2) to 7.4% (5.4-10.0), p = 0.002] and a significant increase in fibrous percentage [from 83.3% ± 6.6-85.5% ± 4.8, p = 0.039]. None of the studied functional blood biomarkers were related to either baseline carotid plaque lipid content or its propensity to change with statin treatment.

CONCLUSIONS

T2-mapping demonstrated depleted carotid plaque lipid following the initiation of high-intensity statin treatment. Standard or 'functional' blood biomarkers were dissociated from plaque lipid content or changes with treatment. These findings further reinforce the importance of disease characterisation over risk factor assessment. Subject to clinical trial findings, quantification of plaque lipid may provide the basis for an approach to identify patients suitable for intensive lipid reduction regimes.

Serum Lipid Profile and Its Association with Diabetes and Prediabetes in a Rural Bangladeshi Population

Dyslipidemia is commonly associated with diabetes (T2DM). This has been demonstrated for the Caucasian population, but few data are available for Asian Indians. The paper aims to investigate serum lipids (separately or in combination) and their association with glucose intolerance status (T2DM and prediabetes) in a rural Bangladeshi population. A sample of 2293 adults (≥20 years) were included in a community based cross-sectional survey in 2009. Anthropometric measures, blood pressure, blood glucose (fasting and 2-h oral glucose tolerance test) and fasting serum lipids (total cholesterol, T-Chol; triglycerides, Tg; low density lipoprotein cholesterol, LDL-C and high density lipoprotein cholesterol, HDL-C) were registered. Analysis of covariance (ANCOVA) and regression analysis were performed. High Tg levels were seen in 26% to 64% of the participants, depending on glucose tolerance status. Low HDL-C levels were seen in all groups (>90%). Significant linear trends were observed for high T-Chol, high Tg and low HDL-C with increasing glucose intolerance (p for trend <0.001). T2DM was significantly associated with high T-Chol (Odds ratio (OR): 2.43, p < 0.001), high Tg (OR: 3.91, p < 0.001) and low HDL-C (OR: 2.17, p = 0.044). Prediabetes showed a significant association with high Tg (OR: 1.96, p < 0.001) and low HDL-C (OR: 2.93, p = 0.011). Participants with combined high Tg and low HDL-C levels had a 12.75-fold higher OR for T2DM and 4.89 OR for prediabetes. In Asian Indian populations an assessment of serum lipids is warranted not only for T2DM patients, but also for those with prediabetes.

Cholesterol efflux capacity does not associate with coronary calcium, plaque vulnerability, and telomere length in healthy octogenarians

Several studies have revealed that traditional risk factors are less effective in predicting CVD risk in the elderly, suggesting the need to identify new biomarkers. Here, we evaluated the association between serum cholesterol efflux capacity (CEC), an atheroprotective property of HDL recently identified as a novel marker of CVD risk, and atherosclerotic burden in a cohort of very old, healthy individuals. Serum CEC values were not significantly correlated either with calcium score or with markers of vulnerable plaque, such as positive remodeling, hypodensity, spotty calcification, or napking-ring sign. In addition, no association was detected between CEC and telomere length, a marker of biological aging that has been linked to atherosclerosis extent. Interestingly, elderly subjects presented a remarkably higher CEC (+30.2%; P < 0.0001) compared with values obtained from a cohort of sex-matched, cardiovascular event-free, middle-aged individuals. In conclusion, serum CEC is not related to traditional risk factors in very old, cardiovascular event-free subjects, but has significantly higher values compared with a healthy, younger population. Whether this improved HDL functionality may represent a protective factor in CVD onset must be established in future studies.

NaoXinTong Enhances Atorvastatin-induced Plaque Stability While Ameliorating Atorvastatin-induced Hepatic Inflammation

Buchang NaoXinTong (NXT) is a Chinese medicine that has been used for many years for treatment of patients with coronary heart disease (CHD) in China. Statins substantially reduce hypercholesterolemia and CHD mortality and morbidity. However, there is still a lot of CHD patients who do not respond well to statin therapy. Herein, we report the effects of NXT on atorvastatin-inhibited atherosclerosis and atorvastatin-induced hepatic side effects. After 10 weeks of high-fat diet (HFD) feeding, apoE-deficient mice were randomly divided into 4 groups and received the following treatment for another 8 weeks: group 1, HFD; group 2, HFD containing NXT; group 3, HFD containing atorvastatin; and group 4, HFD containing both NXT and atorvastatin. After treatment, serum lipid profiles, atherosclerotic lesions, and hepatic lipid content and inflammation were determined. NXT moderately increased high-density lipoprotein cholesterol levels, although had little effect on atorvastatin-induced reduction of low-density lipoprotein cholesterol levels. Both NXT and atorvastatin reduced en face lesions and sinus lesions of aortic root. In addition, NXT enhanced atorvastatin-induced lesion plaque stability by increasing smooth muscle cell/collagen content and reducing macrophage accumulation and calcification in lesion areas. The co-treatment of NXT and atorvastatin further reduced hepatic triglyceride levels by downregulating acyl-CoA:diacylglycerol acyltransferase 1 while activating hormone-sensitive lipase, adipose triglyceride lipase, and comparative gene identification-58 expression. The AMPKα pathway was also further activated by the co-treatment. More importantly, the liver injuries caused by atorvastatin, such as hepatic inflammation and elevated serum aminotransferase activities, were substantially attenuated by NXT. Therefore, our study demonstrates that NXT enhances atorvastatin-induced plaque stability and ameliorates atorvastatin-induced hepatic side effects.

High-density Lipoprotein and Low-density Lipoprotein Therapeutic Approaches in Acute Coronary Syndromes

BACKGROUND

Low-density lipoprotein cholesterol (LDL), and especially its oxidized form, renders the atherosclerotic plaque vulnerable to rupture in acute coronary syndromes (ACS). On the other hand, high-density lipoprotein (HDL) is considered an anti-atherogenic molecule. The more recent HDL-targeted drugs may prove to be superior to those used before. Indeed, delipidated HDL and HDL mimetics are efficient in increasing HDL levels, while the apoA-I upregulation with RVX-208 appears to offer a clinical benefit which is beyond the HDL related effects. HDL treatment however has not shown a significant improvement in the outcomes of patients with ACS so far, studies have therefore focused again on LDL. In addition to statins and ezetimibe, novel drugs such as PSCK9 inhibitors and apolipoprotein B inhibitors appear to be both effective and safe for patients with hyperlipidemia.

CONCLUSION

Data suggest these could potentially improve the cardiovascular outcomes of patient with ACS. Yet, there is still research to be done, in order to confirm whether ACS patients would benefit from LDL- or HDL-targeted therapies or a combination of both.

Apolipoprotein C-I Polymorphism and Its Association with Serum Lipid Levels and Longevity in the Bama Population

This study aims to determine the association between the apolipoprotein C-I polymorphism and the longevity and genetic variants in ApoC-I that can influence the serum lipid levels in Bama. ApoC-I genotypes were determined by Taqman single nucleotide polymorphism (SNP) genotyping assays in 178 long-lived inhabitants (longevity group aged from 90 to 110 years), 147 healthy controls (Control 1 group aged from 40 to 79 years old) from Bama County, and 190 healthy controls (Control 2 group aged from 40 to 79 years old) from Nandan County without a family history of longevity. Statistical analysis was conducted using SPSS 16.0. All genotype distributions of rs584007 and rs4420638 were consistent with the Hardy-Weinberg equilibrium (p > 0.05). Significant differences were observed in the frequencies of the three genotypes (GG, AG, and AA) among the longevity and the two control groups (χ² = 11.238, p = 0.024) for rs584007. No significant differences were observed in the frequencies of the three genotypes (GG, AG, and AA) among the longevity and the two control groups (χ² = 4.587, p = 0.318) for rs4420638. The levels of total cholesterol (TC), triglycerides (TG), high-density lipoprotein-cholesterol (HDL-c), and low-density lipoprotein-cholesterol (LDL-c) were not different among the three genotypes of rs584007 in the three groups. The levels of HDL-c for GG, AG, and AA were significantly different (the highest being in the longevity group), while the levels of TG for AA and AG genotypes (the lowest being in the longevity group) and the levels of LDL-c for AG were significantly different (p < 0.05) among the three groups for rs584007. The levels of TG and HDL-c were significantly different among the three rs4420638 genotypes in the longevity group. The levels of TC for GG, AG, and AA were significantly different in the Control 2 group, while the levels of TG and HDL-c for AA and AG genotypes were significantly different (p < 0.05) among the three groups for rs4420638. The level of HDL-c was highest in the longevity group for AA and AG genotypes, and the level of TG was highest in the Control 2 group for rs4420638. Serum lipid parameters were related to environmental factors, including age, gender, BMI, DBP, SBP, rs4420638, and rs584007. The ApoC-I polymorphism might be one of the genetic factors of longevity in Bama. The ApoC-I rs4420638 and rs584007 SNPs are associated with serum TG and HDL-c levels in the longevous population.

Metabolic Syndrome Modulates Association between Endothelial Lipase and Lipid/Lipoprotein Plasma Levels in Acute Heart Failure Patients

We hypothesised that the established association of endothelial lipase (EL) plasma levels with atherogenic lipid profile is altered in acute heart failure (AHF) and additionally affected by overlapping metabolic syndrome (MetS). We examined the association of EL plasma levels and lipid/lipoprotein plasma levels in AHF patients without and with overlapping MetS. The study was performed as a single-centre, observational study on 152 AHF patients, out of which 85 had overlapping MetS. In the no-MetS group, EL plasma levels were significantly positively correlated with plasma levels of atherogenic lipids/lipoproteins, including total cholesterol, low-density lipoprotein (LDL)-cholesterol, total LDL particles and triglycerides, but also with plasma levels of antiatherogenic high-density lipoprotein (HDL)-cholesterol, total HDL particles and small HDL particles. In the MetS group, EL plasma levels were positively correlated with triglyceride and small LDL-particle levels, and significantly negatively correlated with plasma levels of large HDL particles as well as with LDL- and HDL-particle size, respectively. EL- and lipid/lipoprotein- plasma levels were different in the no-MetS patients, compared to MetS patients. The association of EL with atherogenic lipid profile is altered in AHF and additionally modified by MetS, which strongly modulates EL- and lipid/lipoprotein-plasma levels in AHF.

High density lipoproteins are modulators of protease activity: Implications in inflammation, complement activation, and atherothrombosis

High density lipoproteins (HDL) represent a compositionally diverse population of particles in the circulation, containing a wide variety of lipids and proteins. Gene ontology functional analysis of the 96 commonly identified HDL binding proteins reveals that almost half of these proteins are either proteases or have known roles in protease regulation. Here, we discuss the activities of some of these proteins in regard to their roles in regulating proteases involved in inflammation, coagulation, and complement activation, particularly in the context of atherosclerosis. The overall goal of this review is to discuss potential functional roles of HDL in protease regulatory pathways based on current literature and known functions of HDL binding proteins and to promote the consideration of HDL as a global modulator of proteolytic equilibrium.

Regression of atherosclerosis with apple procyanidins by activating the ATP-binding cassette subfamily A member 1 in a rabbit model

BACKGROUND AND AIMS

Apple polyphenol contains abundant procyanidins, which have been associated with an anti-atherosclerosis and cholesterol-lowering effect. The aim of this study was to investigate whether apple procyanidins (APCs) feature therapeutic efficacy in terms of regressing atherosclerosis and whether this efficacy is due to mechanisms other than a cholesterol-lowering effect.

METHODS

After eight weeks on an atherogenic diet, rabbits were given a normal diet for another eight weeks to normalize the increased serum lipids level. The rabbits in the baseline group were sacrificed at this stage. The control group was subsequently fed a normal diet for eight weeks, while the APCs group was administrated 50 mg/kg/day of APCs in addition to the normal diet. Serum lipids and aortic intimal-medial thickness (IMT) were serially examined, and the resected aorta was examined histologically and through molecular biology.

RESULTS

Aortic IMT on ultrasonography and the lipid accumulation area examined using Sudan IV staining were significantly reduced in the APCs group as compared to the control group. Serum lipid profiles were not different between the groups. Immunohistochemistry showed significantly decreased staining of an oxidative stress marker and significantly increased staining of ATP-binding cassette subfamily A member 1 (ABCA1) in the APCs group. Western blotting and RT-PCR also showed increased expression of ABCA1 mRNA and its protein in the APCs group.

CONCLUSIONS

This study revealed that APCs administration causes a regression of atherosclerosis. APCs might hold promise as an anti-atherosclerotic agent.

Lipidomic and Antioxidant Response to Grape Seed, Corn and Coconut Oils in Healthy Wistar Rats

Specialty oils differ in fatty acid, phytosterol and antioxidant content, impacting their benefits for cardiovascular health. The lipid (fatty acid, phytosterol) and antioxidant (total phenolics, radical scavenging capacity) profiles of grapeseed (GSO), corn (CO) and coconut (CNO) oils and their physiological (triacylglycerides, total and HDL-cholesterol and antioxidant capacity (FRAP) in serum and fatty acid and phytosterol hepatic deposition) and genomic (HL, LCAT, ApoA-1 and SR-BP1 mRNA hepatic levels) responses after their sub-chronic intake (10% diet for 28 days) was examined in healthy albino rats. Fatty acid, phytosterol and antioxidant profiles differed between oils (p ≤ 0.01). Serum and hepatic triacylglycerides and total cholesterol increased (p ≤ 0.01); serum HDL-Cholesterol decreased (p < 0.05); but serum FRAP did not differ (p > 0.05) in CNO-fed rats as compared to CO or GSO groups. Hepatic phytosterol deposition was higher (+2.2 mg/g; p ≤ 0.001) in CO- than GSO-fed rats, but their fatty acid deposition was similar. All but ApoA-1 mRNA level increased in GSO-fed rats as compared to other groups (p ≤ 0.01). Hepatic fatty acid handling, but not antioxidant response, nor hepatic phytosterol deposition, could be related to a more efficient reverse-cholesterol transport in GSO-fed rats as compared to CO or CNO.

Association between coronary microvascular function and the vasa vasorum in patients with early coronary artery disease

BACKGROUND AND AIMS

The vasa vasorum (VV) plays a role in the initial phase of atherosclerosis, and abnormalities in microvascular function may be sensitive measures of the early development of atherosclerosis. The current study was designed to access the association between coronary microvascular function and VV density in patients undergoing cardiac catheterization.

METHODS

Twenty-four patients with early coronary artery disease underwent endothelium-dependent (coronary blood flow, CBF) and endothelium-independent (coronary flow velocity reserve, CFVR) coronary microvascular function testing, and optical coherence tomography (OCT) imaging of the left anterior descending coronary artery (LAD). Using an intracoronary Doppler guidewire, CBF was examined by evaluating changes in blood flow in response to acetylcholine and CFVR in response to adenosine. VV density (VV volume/vessel volume × 100, %VV) of the proximal 10 mm of the LAD was quantified by OCT.

RESULTS

The median values (Q1, Q3) of CFVR, % changes in CBF in response to acetylcholine, and the %VV were 2.70 (2.30, 2.90), -16.82 (-42.34, 54.52), and 2.62 (2.35, 3.35), respectively. %VV correlated inversely with CBF (r = -0.614, p = 0.001) and directly with CFVR (r = 0.423, p = 0.040). Multivariate analysis showed that only %VV was significantly correlated with CBF and the association was independent of other clinical variables, Framingham risk score, body mass index, and a family history of coronary heart disease.

CONCLUSIONS

This study demonstrates that VV density has negative correlation with endothelium-dependent microvascular function in patients with early coronary atherosclerosis. These observations link adventitial VV structure and function to microvascular dysfunction in early coronary atherosclerosis.

A non-hypocholesterolemic atorvastatin treatment improves vessel elasticity by acting on elastin composition in WHHL rabbits

BACKGROUND AND AIMS

Statins are prescribed for their preventative effects within atherosclerosis development. To our knowledge, no study focusing on very low-dose (non-hypolipidemic effect) and long-term atorvastatin treatment in vivo was available. Our aim was to assess the effect of such atorvastatin treatment on the mechanical and functional characteristics of arteries in the context of primary prevention.

METHODS

An atorvastatin treatment (2.5 mg/kg/day) was tested against controls on 34 male 3 to 12 month-old WHHL rabbits. No effect on total cholesterol, triglycerides, HDL or LDL was observed. The arterial stiffness was evaluated on vigil animals by pulse wave velocity (PWV) measurement. Then, in vitro measurements were made to evaluate (1) the endothelial and vascular smooth muscle function, (2) the elasticity of the arterial wall and (3) the composition in collagen and elastin in the aorta.

RESULTS

The PWV increasing observed with age in control group was canceled by treatment, creating a significance difference between groups at 12 months (5.17 ± 0.50 vs 2.14 ± 0.34 m s(-1) in control and treated groups respectively). Vasoreactivity modifications can't explain this result but maintain of elasticity with treatment in large arteries was confirm by a static tensile test. A first possible explanation is the change of wall composition with treatment, validated by the percentage of elastin at 12 months, 4.4% lower in the control group compared to the treated group (p < 0.05).

CONCLUSIONS

This study shows that a non-hypocholesterolemic statin treatment could improve vessel elasticity in the atherosclerotic WHHL model. The great novelty of this work is the vessel wall composition changing associated. This first approach in animal opens the reflection on the use of these low doses in humans. This could be interesting in the context of arterial stiffening with aging, non-hyperlipidemic atherosclerosis or with cholesterol reduce by another therapy or lifestyle modification.

Development of a tree shrew metabolic syndrome model and use of umbilical cord mesenchymal stem cell transplantation for treatment

The aim of this study was to establish a tree shrew metabolic syndrome model and demonstrate the utility of MSCs in treating metabolic syndrome. We used tree shrew umbilical cord mesenchymal stem cell (TS-UC-MSC) transplantation for the treatment of metabolic syndrome to demonstrate the clinical application of these stem cells and to provide a theoretical basis and reference methods for this treatment. Tree shrew metabolic syndrome model showed significant insulin resistance, high blood sugar, lipid metabolism disorders, and hypertension, consistent with the diagnostic criteria. TS-UC-MSC transplantation at 16 weeks significantly reduced blood sugar and lipid levels, improved insulin resistance and the regulation of insulin secretion, and reduced the expression levels of the pro-inflammatory cytokines IL-1 and IL-6 (P < 0.05). The transplanted TS-UC-MSCs targeted the liver, kidney and pancreas; reduced liver cell degeneration, necrosis, and inflammatory exudation; mitigated bleeding congestion and inflammatory cell infiltration in the kidney; and reduced islet cell degeneration and necrosis. We successfully developed a tree shrew metabolic syndrome model and showed that MSC migrate in diseased organs and can attenuate metabolic syndrome severity in a tree shrew model.

Postmenopausal Women Have Higher HDL and Decreased Incidence of Low HDL than Premenopausal Women with Metabolic Syndrome

It is well known that plasma lipids, waist circumference (WC) and blood pressure (BP) increase following menopause. In addition, there is a perceived notion that plasma high-density lipoprotein-cholesterol (HDL-C) concentrations also decrease in postmenopausal women. In this cross-sectional study, we evaluated plasma lipids, fasting glucose, anthropometrics and BP in 88 post and 100 pre-menopausal women diagnosed with metabolic syndrome. No differences were observed in plasma low-density lipoprotein-cholesterol cholesterol, triglycerides, fasting glucose or systolic and diastolic BP between groups. However, plasma HDL-C was higher (p < 0.01) in postmenopausal women and the percentage of women who had low HDL (<50 mg/dL) was higher (p < 0.01) among premenopausal women. In addition, negative correlations were found between WC and HDL-C (r = -0.148, p < 0.05) and BMI and HDL-C (r = -0.258, p < 0.01) for all subjects indicating that increases in weight and abdominal fat have a deleterious effect on plasma HDL-C. Interestingly, there was a positive correlation between age and plasma HDL-C (r = 0.237 p < 0.01). The results from this study suggest that although HDL is decreased by visceral fat and overall weight, low HDL is not a main characteristic of metabolic syndrome in postmenopausal women. Further, HDL appears to increase, not decrease, with age.

Effect of beta-3 adrenoceptor stimulation on the levels of ApoA-I, PPARα, and PPARγ in apolipoprotein E-deficient mice

The beta-3 adrenoceptor (β3-AR) protects against the progression of atherosclerosis. However, the specific mechanism of this antiatherosclerotic effect is still not clear. Thus, the aim of this study was to understand the antiatherosclerotic effects of β3-AR. Thirty-six male homozygous apolipoprotein E-deficient mice and wild-type C57BL/6J mice were randomized into 6 treatment groups: wild-type, atherosclerotic model, atorvastatin, low-dose β3-AR agonist, high-dose β3-AR agonist, and β3-AR antagonist groups. The serum lipids, aortic-free cholesterol (FC), and cholesteryl ester (CE) concentrations were measured at the end of the treatments. The mRNA expression levels of liver apolipoprotein A-I (apoA-I), peroxisome proliferator-activated receptor-α (PPARα), and peroxisome proliferator-activated receptor-γ (PPARγ) were detected by quantitative real-time PCR. Protein expression levels of apoA1, PPARα, and PPARγ in the liver were determined by western blot analysis. Treatment with β3-AR significantly increased the plasma levels of high-density lipoprotein cholesterol and apoA-I, whereas the levels of total cholesterol, triglycerides, and low-density lipoprotein cholesterol decreased. The β3-AR agonist treatment markedly decreased both the FC and the CE concentrations in the aorta compared with the atherosclerotic model mice. The β3-AR agonist increased the mRNA and protein expression levels of apoA-I, PPARα, and PPARγ in the liver. This study demonstrates that long-term β3-AR activation can regulate lipid metabolic disorders and reduces the aortic FC and the CE concentrations. These effects may be related to apoA-I, PPARα, and PPARγ.

Beginning to understand high-density lipoproteins

This article reconciles the classic view of high-density lipoproteins (HDL) associated with low risk for cardiovascular disease (CVD) with recent data (genetics studies and randomized clinical trials) casting doubt over the widely accepted beneficial role of HDL regarding CVD risk. Although HDL cholesterol has been used as a surrogate measure to investigate HDL function, the cholesterol content in HDL particles is not an indicator of the atheroprotective properties of HDL. Thus, more precise measures of HDL metabolism are needed to reflect and account for the beneficial effects of HDL particles. Current and emerging therapies targeting HDL are discussed.

Atheroprotective effects of (poly)phenols: a focus on cell cholesterol metabolism

Collated observations from several epidemiological studies have demonstrated that dietary intake of (poly)phenols from nuts, coffee, cocoa, grapes, and berries may protect against the development of atherosclerosis. Whereas this beneficial activity has previously been linked mainly to antioxidant or anti-inflammatory properties, recently emerging data suggest mechanisms by which (poly)phenolic substances can modulate cellular lipid metabolism, thereby mitigating atherosclerotic plaque formation. In this review, both experimental studies and clinical trials investigating the atheroprotective effects of the most relevant dietary (poly)phenols are critically discussed.

An eicosanoid-centric view of atherothrombotic risk factors

Cardiovascular disease is the foremost cause of morbidity and mortality in the Western world. Atherosclerosis followed by thrombosis (atherothrombosis) is the pathological process underlying most myocardial, cerebral, and peripheral vascular events. Atherothrombosis is a complex and heterogeneous inflammatory process that involves interactions between many cell types (including vascular smooth muscle cells, endothelial cells, macrophages, and platelets) and processes (including migration, proliferation, and activation). Despite a wealth of knowledge from many recent studies using knockout mouse and human genetic studies (GWAS and candidate approach) identifying genes and proteins directly involved in these processes, traditional cardiovascular risk factors (hyperlipidemia, hypertension, smoking, diabetes mellitus, sex, and age) remain the most useful predictor of disease. Eicosanoids (20 carbon polyunsaturated fatty acid derivatives of arachidonic acid and other essential fatty acids) are emerging as important regulators of cardiovascular disease processes. Drugs indirectly modulating these signals, including COX-1/COX-2 inhibitors, have proven to play major roles in the atherothrombotic process. However, the complexity of their roles and regulation by opposing eicosanoid signaling, have contributed to the lack of therapies directed at the eicosanoid receptors themselves. This is likely to change, as our understanding of the structure, signaling, and function of the eicosanoid receptors improves. Indeed, a major advance is emerging from the characterization of dysfunctional naturally occurring mutations of the eicosanoid receptors. In light of the proven and continuing importance of risk factors, we have elected to focus on the relationship between eicosanoids and cardiovascular risk factors.