C-reactive protein inhibits cholesterol efflux from human macrophage-derived foam cells

Lipid-to-neutrophil ratios in predicting in-hospital outcomes in pulmonary thromboembolism

Introduction

Acute pulmonary thromboembolism (PTE) is one of the leading causes of death and severe disability. Considering the impact of inflammation and lipid profile on prevalence and prognosis of deep vein thrombosis and PTE, this study was conducted to assess the predictive value of lipid-to-neutrophil count ratios for the short-term survival of PTE patients.

Methods

This study is an analytical cross-sectional study. Data regarding the demographics, past medical history, vital signs, laboratory variables, and the outcomes of hospitalization were gathered from the Tabriz PTE registry. The receiver operating characteristics (ROC) curve and area under curve (AUC) were utilized for assessing the prognostic values. SPSS 26 was used for all of the statistical analysis.

Results

The population of this analytical cross-sectional study consists of 547 PTE patients of which 41 patients (7.5%) died during hospitalization. There was a significant difference between death and survived groups regarding cholesterol (146.00[60.50] vs. 165.50[59.75]; p-value<0.01), LDL (80.00[48.00] vs. 102.00[52.00]; p-value<0.01), HDL (31.00[19.00] vs. 35.00[14.00]; p-value=0.04). Cholesterol/neutrophil*1000 with a cut-off value of 22.014 (sensitivity: 56.7%; specificity: 61.3%), LDL/neutrophil*1000 with a cut-off value of 10.909 (sensitivity: 69.3%; specificity: 51.9%) and HDL/neutrophile *1000 with a cut-off value of 4.150 (sensitivity: 61.9%; specificity: 58.1%) can predict short-term survival in patients with acute PTE.

Conclusion

Based on our findings, patients with higher cholesterol/neutrophil, LDL/neutrophil, and HDL/neutrophil ratios have a better in-hospital prognosis and measurement of lipid-to-neutrophil ratio in the first 24 hours of hospitalization may be a valuable marker for determining the early prognosis of PTE. However, additional clinical studies are suggested for a more definitive conclusion.

Lipid profile and mortality in patients with pulmonary thromboembolism; a systematic review and meta-analysis

INTRODUCTION

Acute pulmonary thromboembolism (PTE) is a life-threatening disease. Considering the availability and accessibility of assessing the serum lipids, this study aims to define the predictive value of lipid profile, as well as the history of lipid disorders, for the mortality of PTE patients.

CONTENT

Clinical studies, in which the relation of lipid profile, including triglyceride (TG), low-density lipoprotein (LDL), high-density lipoprotein (HDL), and total cholesterol, as well as history of imbalance of lipids, with mortality of PTE patients was reported, were included. Non-English articles, reviews, letters, editorials, and non-English papers were excluded. A systematic search was conducted in PubMed, Embase, Scopus, and Web of Science databases. The risk of bias was assessed using the Joanna Briggs Institute (JBI) Critical Appraisal tools and CMA 4 was utilized for the quantitative synthesis. Out of 3,724 records, six studies were included in this systematic review. Lipid profile is suggested as a prognostic marker for survival in patients with PTE so higher initial serum HDL, LDL, and total cholesterol levels were associated with lower mortality rates in PTE patients. In addition, dyslipidemia was found to be associated with mortality of PTE patients. Based on the quantitative synthesis, there was a greater serum level of HDL in the survival group (standardized mean difference: -0.98; 95 % CI: -1.22 to -0.75; p-value<0.01).

SUMMARY AND OUTLOOK

Mortality is lower in PTE patients with greater serum lipid levels; therefore, the early prognosis of PTE may be ascertained by measuring serum lipids within the first 24 h of admission.

Mito-Tempo alleviates ox-LDL-provoked foam cell formation by regulating Nrf2/NLRP3 signaling

Our previous studies have demonstrated that Mito-Tempol (also known as 4-hydroxy-Tempo), a mitochondrial reactive oxygen species scavenger, alleviates oxidized low-density lipoprotein (ox-LDL)-triggered foam cell formation. Given the effect of oxidative stress on activating the NOD-, LRR-, and pyrin domain-containing 3 (NLRP3) inflammasome, which promotes foam cell formation, we aimed to explore whether Mito-Tempo inhibits ox-LDL-triggered foam cell formation by regulating NLRP3 inflammasome. The results revealed that Mito-Tempo re-activated Nrf2 and alleviated macrophage foam cell formation induced by ox-LDL, whereas the effects were reversed by ML385 (a specific Nrf2 inhibitor). Mito-Tempo restored the expression and nuclear translocation of Nrf2 by decreasing ox-LDL-induced ubiquitination. Furthermore, Mito-Tempo suppressed ox-LDL-triggered NLRP3 inflammasome activation and subsequent pyroptosis, whereas the changes were blocked by ML385. Mito-Tempo decreased lipoprotein uptake by inhibiting CD36 expression and suppressed foam cell formation by regulating the NLRP3 inflammasome. Taken together, Mito-Tempo exhibits potent anti-atherosclerotic effects by regulating Nrf2/NLRP3 signaling.

A novel prognostic prediction indicator in patients with acute pulmonary embolism: Naples prognostic score

Acute pulmonary embolism (APE) is a potentially fatal disease. Early risk stratification is essential to determining appropriate treatment. We aimed to investigate the predictive value of the Naples Prognostic Score (NPS) for 30-day all-cause mortality in patients with APE. In this retrospective analysis, 325 hospitalized patients with APE were divided into Groups 0 (n = 131), 1 (n = 153), and 2 (n = 41) according to the NPS. The primary outcome event was all-cause mortality during 30 days of follow-up from the day of admission. The correlation between NPS, clinical features, and outcomes in each group was evaluated. The patients were divided into two groups, survivor (n = 294) and nonsurvivor (n = 31), according to their prognosis. The results of the comparison between the three NPS groups revealed that patients with older age, faster heart rate, lower systolic blood pressure, low albumin and total cholesterol levels, high neutrophil to lymphocyte ratio (NLR), low lymphocyte-to-monocyte ratio (LMR), right heart dilatation, heart failure, malignancy, and lower extremity venous thrombosis had significantly higher 30-day all-cause mortality (P < 0.05). Area under the receiver operating characteristic curve (AUC) for NPS to predict all-cause death within 30 days in patients with APE was 0.780 (95% confidence interval [CI] = 0.678-0.855), with sensitivity being 80.6% (95% CI = 0.667-0.946) and specificity being 72.1% (95% CI = 0.670-0.772). Kaplan-Meier (KM) curves showed that Group 2 APE patients had the highest risk of all-cause mortality compared with the other two groups (log-rank test, P = 0.0004). Forest plot visualization using the Cox proportional hazard model showed a significant increase in the risk of 30-day all-cause mortality by 239% (hazard ratio [HR] = 3.385 [1.115-10.273], P = 0.031) and 338% (HR = 4.377 [1.228-15.598], P = 0.023), and the trend test showed a statistical difference (P = 0.042). The study concluded that NPS is a novel, reliable, and multidimensional prognostic scoring system with good prediction of 30-day all-cause mortality in patients with APE.

C-Reactive Protein in Atherosclerosis-More than a Biomarker, but not Just a Culprit

C-reactive protein (CRP) is a pentraxin that is mainly synthesized in the liver in response to inflammatory cytokines. It exists in two functionally and structurally distinct isoforms. The first is a highly pro-inflammatory and mostly tissue-bound monomeric isoform (mCRP). The second is circulating pentameric CRP (pCRP), which also serves as a substrate for the formation of mCRP. CRP is elevated during inflammatory conditions and is associated with a higher risk of cardiovascular disease. The aim of this review is to examine the current state of knowledge regarding the role of these two distinct CRP isoforms on atherogenesis. This should allow further evaluation of CRP as a potential therapeutic target for atherosclerosis. While it seems clear that CRP should be used as a therapeutic target for atherosclerosis and cardiovascular disease, questions remain about how this can be achieved. Current data suggests that CRP is more than just a biomarker of atherosclerosis and cardiovascular disease. Indeed, recent evidence shows that mCRP in particular is strongly atherogenic, whereas pCRP may be partially protective against atherogenesis. Thus, further investigation is needed to determine how the two CRP isoforms contribute to atherogenesis and the development of cardiovascular disease.

ATP-binding cassette G1 membrane transporter-mediated cholesterol efflux capacity influences coronary atherosclerosis and cardiovascular risk in Rheumatoid Arthritis

OBJECTIVES

Cholesterol efflux capacity (CEC) measures the ability of high-density lipoprotein (HDL) to remove cholesterol from macrophages and reduce the lipid content of atherosclerotic plaques. CEC inversely associated with cardiovascular risk beyond HDL-cholesterol levels. CEC through the ATP-binding-cassette G1 (ABCG1) membrane transporter is impaired in rheumatoid arthritis (RA). We evaluated associations of ABCG1-CEC with coronary atherosclerosis, plaque progression and cardiovascular risk in RA.

METHODS

Coronary atherosclerosis (noncalcified, partially, fully-calcified, low-attenuation plaque) was assessed with computed tomography angiography in 140 patients and reevaluated in 99 after 6.9 ± 0.3 years. Cardiovascular events including acute coronary syndromes, stroke, cardiovascular death, claudication, revascularization and hospitalized heart failure were recorded. ABCG1-CEC was measured in Chinese hamster ovary cells as percentage of effluxed over total intracellular cholesterol.

RESULTS

ABCG1-CEC inversely associated with extensive atherosclerosis (≥5 plaques) (adjusted odds ratio 0.50 [95% CI 0.28-0.88]), numbers of partially-calcified (rate ratio [RR] 0.71 [0.53-0.94]) and low-attenuation plaques (RR 0.63 [0.43-0.91] per standard deviation increment). Higher ABCG1-CEC predicted fewer new partially-calcified plaques in patients with lower baseline and time-averaged CRP and fewer new noncalcified and calcified plaques in those receiving higher mean prednisone dose. ABCG1-CEC inversely associated with events in patients with but not without noncalcified plaques, with <median but not higher CRP and in prednisone users but not nonusers (p-for-interaction = 0.021, 0.033 and 0.008 respectively).

CONCLUSION

ABCG1-CEC inversely associated with plaque burden and vulnerability, and plaque progression conditionally on cumulative inflammation and corticosteroid dose. ABCG1-CEC inversely associated with events specifically in patients with noncalcified plaques, lower inflammation and in prednisone users.

The Lipid Paradox as a Metabolic Checkpoint and Its Therapeutic Significance in Ameliorating the Associated Cardiovascular Risks in Rheumatoid Arthritis Patients

While the most common manifestations associated with rheumatoid arthritis (RA) are synovial damage and inflammation, the systemic effects of this autoimmune disorder are life-threatening, and are prevalent in 0.5–1% of the population, mainly associated with cardiovascular disorders (CVDs). Such effects have been instigated by an altered lipid profile in RA patients, which has been reported to correlate with CV risks. Altered lipid paradox is related to inflammatory burden in RA patients. The review highlights general lipid pathways (exogenous and endogenous), along with the changes in different forms of lipids and lipoproteins in RA conditions, which further contribute to elevated risks of CVDs like ischemic heart disease, atherosclerosis, myocardial infarction etc. The authors provide a deep insight on altered levels of low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C) and triglycerides (TGs) in RA patients and their consequence on the cardiovascular health of the patient. This is followed by a detailed description of the impact of anti-rheumatoid therapy on the lipid profile in RA patients, comprising DMARDs, corticosteroids, anti-TNF agents, anti-IL-6 agents, JAK inhibitors and statins. Furthermore, this review elaborates on the prospects to be considered to optimize future investigation on management of RA and treatment therapies targeting altered lipid paradigms in patients.

Cardiovascular Risk in Rheumatoid Arthritis and Mechanistic Links: From Pathophysiology to Treatment

Rheumatoid arthritis (RA) is an autoimmune inflammatory arthritis. Inflammation, however, can spread beyond the joints to involve other organs. During the past few years, it has been well recognized that RA associates with increased risk for cardiovascular (CV) disease (CVD) compared with the general population. This seems to be due not only to the increased occurrence in RA of classical CVD risk factors and comorbidities like smoking, obesity, hypertension, diabetes, metabolic syndrome, and others but also to the inflammatory burden that RA itself carries. This is not unexpected given the strong links between inflammation and atherosclerosis and CVD. It has been shown that inflammatory cytokines which are present in abundance in RA play a significant role in every step of plaque formation and rupture. Most of the therapeutic regimes used in RA treatment seem to offer significant benefits to that end. However, more studies are needed to clarify the effect of these drugs on various parameters, including the lipid profile. Of note, although pharmacological intervention significantly helps reduce the inflammatory burden and therefore the CVD risk, control of the so-called classical risk factors is equally important. Herein, we review the current evidence for the underlying pathogenic mechanisms linking inflammation with CVD in the context of RA and reflect on the possible impact of treatments used in RA.

Expression levels of miR-27a, miR-329, ABCA1, and ABCG1 genes in peripheral blood mononuclear cells and their correlation with serum levels of oxidative stress and hs-CRP in the patients with coronary artery disease

Atherosclerosis is a chronic inflammatory disease with high mortality worldwide. The reverse cholesterol transport pathway in macrophage plays an important role in the pathogenesis of coronary artery disease (CAD) and is strongly controlled by regulatory factors. The microRNAs can promote or prevent the formation of atherosclerotic lesions by post-transcriptional regulation of vital genes in this pathway. Therefore, this study was conducted to investigate the relationship between the expression levels of miR-27a, miR-329, ABCA1, and ABCG1 genes and serum levels of hs-CRP, ox-LDL, and indices of oxidative stress in the patients with established CAD and controls. A total of 84 subjects (42 patients with CAD and 42 controls) were included in this study. Expression levels of miR-27a-3p, miR-329-3p, ABCA1, and ABCG1 genes in the peripheral blood mononuclear cells (PBMCs) and serum concentration of hs-CRP and ox-LDL were measured by real time-PCR and ELISA, respectively. Also, oxidative stress parameters in the serum were evaluated by ferric-reducing antioxidant power (FRAP) and malondialdehyde (MDA) assays. ABCA1 and ABCG1 gene expression in PBMC and serum concentration of FRAP were significantly lower in the CAD group compared to the control group. Expression levels of miR-27a and miR-329 and serum levels of hs-CRP, ox-LDL, and MDA were significantly higher in the CAD group compared to the control group. Serum levels of hs-CRP, ox-LDL, and expression level of miR-27a have inversely related to ABCA1 and ABCG1 gene expression in all the subjects. An increase in the expression levels of miR-27a and miR-329 may lead to the progression of atherosclerosis plaque by downregulating the expression of ABCA1 and ABCG1 genes.

The Effect of Inflammation and Insulin Resistance on Lipid and Lipoprotein Responsiveness to Dietary Intervention

Lipids and lipoproteins are major targets for cardiovascular disease (CVD) prevention. Findings from a limited number of clinical trials suggest diet-induced atherogenic lipoprotein lowering can be altered in the presence of chronic low-grade inflammation or insulin resistance. This review summarizes results from randomized controlled trials that have examined diet-induced changes in lipids/lipoproteins by inflammatory or insulin sensitivity status. In addition, mechanisms to explain these clinical observations are explored. Post hoc analyses of data from a limited number of randomized controlled trials suggest attenuation of diet-induced lipid/lipoprotein lowering in individuals with inflammation and/or insulin resistance. These findings are supported by experimental studies showing that inflammatory stimuli and hyperinsulinemia alter genes involved in endogenous cholesterol synthesis and cholesterol uptake, reduce cholesterol efflux, and increase fatty acid biosynthesis. Further a priori defined research is required to better characterize how chronic low-grade inflammation and insulin resistance modulate lipid and lipoprotein responsiveness to guide CVD risk reduction in individuals presenting with these phenotypes.

Analysis of Low Molecular Weight Substances and Related Processes Influencing Cellular Cholesterol Efflux

Cholesterol efflux is the key process protecting the vascular system from the development of atherosclerotic lesions. Various extracellular and intracellular events affect the ability of the cell to efflux excess cholesterol. To explore the possible pathways and processes that promote or inhibit cholesterol efflux, we applied a combined cheminformatic and bioinformatic approach. We performed a comprehensive analysis of published data on the various substances influencing cholesterol efflux and found 153 low molecular weight substances that are included in the Chemical Entities of Biological Interest (ChEBI) database. Pathway enrichment was performed for substances identified within the Reactome database, and 45 substances were selected in 93 significant pathways. The most common pathways included the energy-dependent processes related to active cholesterol transport from the cell, lipoprotein metabolism and lipid transport, and signaling pathways. The activators and inhibitors of cholesterol efflux were non-uniformly distributed among the different pathways: the substances influencing ‘biological oxidations’ activate cholesterol efflux and the substances influencing ‘Signaling by GPCR and PTK6’ inhibit efflux. This analysis may be used in the search and design of efflux effectors for therapies targeting structural and functional high-density lipoprotein deficiency.

Ambient Air Pollution Is Associated With HDL (High-Density Lipoprotein) Dysfunction in Healthy Adults

Objective- We aimed to assess whether exposure to higher levels of ambient air pollution impairs HDL (high-density lipoprotein) function and to elucidate the underlying biological mechanisms potentially involved. Approach and Results- In the Beijing AIRCHD study (Air Pollution and Cardiovascular Dysfunction in Healthy Adults), 73 healthy adults (23.3±5.4 years) were followed-up with 4 repeated study visits in 2014 to 2016. During each visit, ambient air pollution concentrations, HDL function metrics, and parameters of inflammation and oxidative stress were measured. Average daily concentrations of ambient particulate matter in diameter <2.5 μm were 62.9 µg/m³ (8.1-331.0 µg/m³). We observed significant decreases in HDL cholesterol efflux capacity of 2.3% (95% CI, -4.3 to -0.3) to 5.0% (95% CI, -7.6 to -2.4) associated with interquartile range increases in moving average concentrations of particulate matter in diameter <2.5 μm and traffic-related air pollutants (black carbon, nitrogen dioxide, and carbon monoxide) during the 1 to 7 days before each participant's clinic visit. Higher ambient air pollutant levels were also associated with significant reductions in circulating HDL cholesterol and apoA-I (apolipoprotein A-I), as well as elevations in HDL oxidation index, oxidized LDL (low-density lipoprotein), malondialdehyde, and high-sensitivity C-reactive protein. Conclusions- Higher ambient air pollution concentrations were associated with impairments in HDL functionality, potentially because of systemic inflammation and oxidative stress. These novel findings further our understanding of the mechanisms whereby air pollutants promote cardiometabolic disorders.

Prognostic value of lipid levels in short-term outcome after TAVI

BACKGROUND

A satisfactory risk score specific to transaortic valve implantation (TAVI) procedure is strongly needed for accurate assessment of postprocedural mortality and outcome. The purpose of this study was to investigate the association between certain clinical and laboratory parameters, particularly serum cholesterol levels, and major adverse cardiac events in patients who underwent TAVI.

METHOD

We retrospectively analyzed 119 patients who underwent TAVI at our institution between 2008 and 2016. The independent relationship between clinical and laboratory parameters and major adverse cardiac and cerebrovascular events (MACCE) was analyzed by regression analysis.

RESULTS

In all, 34 patients (28%) experienced MACCE during hospitalization and within 30 days of the procedure. Low-density lipoprotein cholesterol (LDL-C) and high-density lipoprotein cholesterol (HDL-C) levels were significantly lower in the MACCE(+) group compared with the MACCE(-) group (91.9 ± 38 vs. 110.8 ± 38.1 mg/dl, p = 0.01; 33.7 ± 7.3 vs. 38.1 ± 9.8 mg/dl, p = 0.02, respectively). In multivariate logistic regression analysis, age, white blood cell count (WBC), and lower levels of LDL-C and HDL-C were found to be independently correlated with MACCE in the study population. Receiver operating curve (ROC) analysis revealed that an LDL value higher than 71 mg/dl predicted MACCE with a sensitivity of 45.4% and a specificity of 91.8% (AUC: 0.814; p = 0.02).

CONCLUSION

This study suggests that lower serum LDL-C and HDL-C levels are independently associated with short-term MACCE in post-TAVI patients. Lower levels of LDL and HDL cholesterol may indicate a poor prognosis. Measurement of serum lipid levels might improve the preoperative risk assessment of potential TAVI candidates.

ABCA1 and metabolic syndrome; a review of the ABCA1 role in HDL-VLDL production, insulin-glucose homeostasis, inflammation and obesity

ATP-binding cassette transporter A1 (ABCA1) is an integral cell-membrane protein that mediates the rate-limiting step of high density lipoprotein (HDL) biogenesis and suppression of inflammation by triggering a number of signaling pathways via interacting with an apolipoprotein acceptor. The hepatic ABCA1 is involved in regulation of very low density lipoprotein (VLDL) production by affecting the apolipoprotein B trafficking and lipidation of VLDL particles. This protein is involved in protecting the function of pancreatic β-cells and insulin secretion by cholesterol homeostasis. Adipose tissue lipolysis is associated with ABCA1 activity. This transporter is involved in controlling obesity and insulin sensitivity by regulating triglyceride (TG) lipolysis and influencing on adiponectin, visfatin, leptin, and GLUT4 genes expression. The ABCA1 of skeletal muscle cells play a role in increasing the glucose uptake by enhancing the Akt phosphorylation and transferring GLUT4 to the plasma membrane. Abnormal status of ABCA1-regulated phenotypes is observed in metabolic syndrome. This syndrome is associated with the occurrence of many diseases. This review is a summary of the role of ABCA1 in HDL and VLDL production, homeostasis of insulin and glucose, suppression of inflammation and obesity controlling to provide a better insight into the association of this protein with metabolic syndrome.

The contribution of chronic intermittent hypoxia to OSAHS: From the perspective of serum extracellular microvesicle proteins

OBJECTIVE

Obstructive sleep apnea hypopnea syndrome (OSAHS) is an independent risk factor for many clinical complications. However, how OSAHS cause multiple organ injury and initiate inter-organ communication remains unclear. Moreover, despite it is well-recognized that chronic intermittent hypoxia (CIH) is a main feature of OSAHS, specific contribution of CIH to overall OSAHS-initiated pathological complications remains unclear. This study aimed to use an unbiased proteomic approach to determine whether OSAHS alters protein profiles of serum extracellular microvesicles (SEMVs) and how CIH contributes to such alterations.

METHODS

Tandem mass tag (TMT)-labeled quantitative proteomics assay was used to compare the differentially expressed proteins (DEPs) in SEMVs of OSAHS patients and non-OSAHS subjects. To evaluate the contribution of CIH to OSAHS, CIH rodent model was constructed and the same comparative proteomics study was performed in SEMVs from CIH and normoxia rats. The similarity and disparity of DEPs and DEPs-related functions predicted by bioinformatics tools were compared in above-mentioned two models, and several DEPs were selected and further verified by ELISA or Western blotting.

RESULTS

TMT-labeled quantitative proteomics assay unravels 32 DEPs in OSAHS patient SEMVs from a total of 560 human SEMV proteins identified. Four DEPs, namely C-reactive protein (CRP), Haptoglobin (HP),Fibronectin (FN1) and Platelet factor 4 (PF4), were further verified by ELISA and three of them (CRP, FN1 and Hp) showed significant difference in expression level between OSAHS and non-OSAHS groups. In SEMVs of rat CIH model, 121 DEPs out of 723 proteins were identified. By comparing the DEPs identified from the two models, 3 proteins (CRP and FN1 and F13a1) were found identical with the same alteration pattern (CRP was upregulated, FN1 and F13a1 were downregulated) in SEMVs from OSAHS patients and CIH rats, which were further verified by Western blotting. Computational functional analysis further revealed the common and distinct DEP-involved pathways under OSAHS or CIH status.

CONCLUSIONS

This study provides the first evidence that OSAHS causes significant alteration in SEMV protein composition, which may contribute to OSAHS-triggered multiple organ injury and organ-to-organ communication. Moreover, we have demonstrated that CIH is the primary contributor for increased inflammatory protein expression in SEMV. As CRP is being increasingly recognized not only as a marker but also a mediator of inflammatory response to tissue injury, increased SEMV CRP in CIH/OSAHS may play an important role in OSAHS-induced tissue injury, suggesting SEMV CRP might be a therapeutic target against OSAHS-related complications.

HDL cholesterol efflux capacity and cholesteryl ester transfer are associated with body mass, but are not changed by diet-induced weight loss: A randomized trial in abdominally obese men

BACKGROUND AND AIMS

Obesity is associated with a lower HDL-mediated cholesterol efflux from macrophages and a higher CETP (cholesteryl ester transfer protein) activity, but effects of weight loss are not clear. In addition, associations with visceral and subcutaneous adipose tissue are not known. We therefore investigated effects of diet-induced weight loss on HDL-mediated cholesterol efflux and cholesterol ester (CE) transfer in abdominally obese men. Differences between normal-weight and abdominally obese men were also examined.

METHODS

Twenty-five apparently healthy, normal-weight men (waist circumference: <94 cm) and 52 abdominally obese men (waist circumference: 102-110 cm) were included. Abdominally obese subjects were randomly allocated to a dietary weight-loss intervention group or a no-weight loss control group. Individuals from the intervention group followed a very-low-calorie diet for 6 weeks to obtain a waist circumference below 102 cm, followed by a 2-week weight-stable period. Cholesterol efflux was measured in BODIPY-labeled murine J774 macrophages. CE transfer was measured by quantifying the transfer of CE from radiolabeled exogenous HDL to apoB-containing lipoproteins.

RESULTS

Cholesterol efflux capacity was 9 percentage point (pp) lower in abdominally obese than in normal-weight men (p≤0.001), while CE transfer was 5 pp higher (p≤0.01). Diet-induced weight-loss of 10.3 kg did not change cholesterol efflux and CE transfer. In addition, stepwise regression analysis did not suggest that the different fat depots are differently related to efflux capacity and CE transfer.

CONCLUSIONS

After a 2-week weight-stable period, dietary weight loss of 10 kg did not improve ABCA1-mediated cholesterol efflux and CE transfer in abdominally obese men.

Changes in High-Density Lipoprotein Cholesterol Efflux Capacity After Bariatric Surgery Are Procedure Dependent

OBJECTIVE

High-density lipoprotein cholesterol efflux capacity (CEC) is inversely associated with incident cardiovascular events, independent of high-density lipoprotein cholesterol. Obesity is often characterized by impaired high-density lipoprotein function. However, the effects of different bariatric surgical techniques on CEC have not been compared. This study sought to determine the effects of Roux-en-Y gastric bypass (RYGB) and sleeve gastrectomy (SG) on CEC.

APPROACH AND RESULTS

We prospectively studied severely obese, nondiabetic, premenopausal Hispanic women not using lipid medications undergoing RYGB (n=31) or SG (n=36). Subjects were examined before and at 6 and 12 months after surgery. There were no differences in baseline characteristics between surgical groups. Preoperative CEC correlated most strongly with Apo A1 (apolipoprotein A1) concentration but did not correlate with body mass index, waist:hip, high-sensitivity C-reactive protein, or measures of insulin resistance. After 6 months, SG produced superior response in high-density lipoprotein cholesterol and Apo A1 quantity, as well as global and non-ABCA1 (ATP-binding cassette transporter A1)-mediated CEC (P=0.048, P=0.018, respectively) versus RYGB. In multivariable regression models, only procedure type was predictive of changes in CEC (P=0.05). At 12 months after SG, CEC was equivalent to that of normal body mass index control subjects, whereas it remained impaired after RYGB.

CONCLUSIONS

SG and RYGB produce similar weight loss, but contrasting effects on CEC. These findings may be relevant in discussions about the type of procedure that is most appropriate for a particular obese patient. Further study of the mechanisms underlying these changes may lead to improved understanding of the factors governing CEC and potential therapeutic interventions to maximally reduce cardiovascular disease risk in both obese and nonobese patients.

Effects of garlic on brachial endothelial function and capacity of plasma to mediate cholesterol efflux in patients with coronary artery disease

Objective:

This study investigated the effects of garlic on brachial endothelial function and THP-1 macrophage cholesterol efflux (CE) and examined whether garlic modulates ATP-binding cassette (ABC) A1 and ABCG1 mRNA expressions in peripheral blood mononuclear cells (PBMCs) isolated from patients with coronary artery disease (CAD).

Methods:

In this randomized, placebo-controlled trial, patients with CAD were randomly divided into two groups: those receiving garlic powder or placebo tablets twice daily for 3 months. Brachial flow-mediated dilation (FMD) was assessed using ultrasound. Fasting blood samples were collected before and after period and PBMC and plasma were isolated. Human THP-1 monocytes were differentiated into macrophages, labeled with 3H-cholesterol, and incubated with plasma samples, and CE was assessed. ABCA1 and ABCG1 mRNA expressions were determined in PBMCs.

Results:

After 3 months, brachial FMD values significantly improved (50.7%) in the garlic group compared with those in the placebo group (p=0.016). High-sensitive C-reactive protein (hs-CRP) levels significantly decreased in the garlic group, but the difference between the two groups was not statistically significant. No significant difference was observed with regard to CE and ABCA1 and ABCG1 mRNA expressions in PBMCs. CE was negatively correlated with hs-CRP levels.

Conclusion:

Short-term treatment with garlic may improve the endothelial function and may affect hs-CRP levels; however, it could neither significantly improve THP-1 macrophage CE nor affect ABCA1 or ABCG1 expressions in PBMCs.

Gly[14]-humanin inhibits ox-LDL uptake and stimulates cholesterol efflux in macrophage-derived foam cells

Foam cell formation, which is caused by imbalanced cholesterol influx and efflux by macrophages, plays a vital role in the occurrence and development of atherosclerosis. Humanin (HN), a mitochondria-derived peptide, can prevent the production of reactive oxygen species and death of human aortic endothelial cells exposed to oxidized low-density lipoprotein (ox-LDL) and has a protective effect on patients with in early atherosclerosis. However, the effects of HN on the regulation of cholesterol metabolism in RAW 264.7 macrophages are still unknown. This study was designed to investigate the role of [Gly14]-humanin (HNG) in lipid uptake and cholesterol efflux in RAW 264.7 macrophages. Flow cytometry and live cell imaging results showed that HNG reduced Dil-ox-LDL accumulation in the RAW 264.7 macrophages. A similar result was obtained for lipid accumulation by measuring cellular cholesterol content. Western blot analysis showed that ox-LDL treatment upregulated not only the protein expression of CD36 and LOX-1, which mediate ox-LDL endocytosis, but also ATP-binding cassette (ABC) transporter A1 and ABCG1, which mediate ox-LDL exflux. HNG pretreatment inhibited the upregulation of CD36 and LOX-1 levels, prompting the upregulation of ABCA1 and ABCG1 levels induced by ox-LDL. Therefore we concluded that HNG could inhibit ox-LDL-induced macrophage-derived foam cell formation, which occurs because of a decrease in lipid uptake and an increase in cholesterol efflux from macrophage cells.

Lck Inhibits Heat Shock Protein 65-Mediated Reverse Cholesterol Transport in T Cells

Previously, we reported that heat shock protein (HSP)65 impairs the effects of high-density lipoprotein on macrophages. We also showed that immune response activation adversely affects reverse cholesterol transport (RCT). In this study, we investigated the effects of the Src family kinase lymphocyte-specific protein tyrosine kinase (Lck) and elucidated the mechanism underlying HSP65-regulated cholesterol efflux in T cells. We evaluated cell proliferation, Lck expression, and inflammatory cytokine production in Jurkat cells and CD4⁺ T cells. HSP65-mediated inhibition of RCT was assessed by evaluating ABCA1, ABCG1, SR-BI, PPAR-γ, and liver X receptor-α expression. A dose-dependent relationship was found between the levels of these proteins and the suppression of cholesterol efflux. Stimulation of Lck-silenced T cells with ionomycin resulted in a decrease in intracellular calcium levels. Treatment of Jurkat cells with PP2, an inhibitor of Src family kinase, inhibited calcium-induced, but not PMA-induced, ERK phosphorylation. NF-κB activation in response to PMA was minimally inhibited in cells stimulated with PP2. HSP65 failed to trigger downstream ERK or JNK phosphorylation or to activate NF-κB or protein kinase C-γ in Lck-silenced cells. Additionally, elevation of intracellular calcium was also impaired. However, HSP65 significantly enhanced cholesterol efflux and decreased cellular cholesterol content by inducing the expression of cholesterol transport proteins in Lck-silenced cells. The treatment of Jurkat cells with PP2 also inhibited cell proliferation and promoted RCT. In conclusion, Lck is a key molecule in the TCR signaling cascade that inhibits cholesterol efflux and upregulates intracellular cholesterol ester content in T cells. Our results demonstrate that the immune response plays a previously unrecognized role in RCT.

Genotype-Dependent Effects of Dalcetrapib on Cholesterol Efflux and Inflammation: Concordance With Clinical Outcomes

BACKGROUND

Dalcetrapib effects on cardiovascular outcomes are determined by adenylate cyclase 9 gene polymorphisms. Our aim was to determine whether these clinical end point results are also associated with changes in reverse cholesterol transport and inflammation.

METHODS AND RESULTS

Participants of the dal-OUTCOMES and dal-PLAQUE-2 trials were randomly assigned to receive dalcetrapib or placebo in addition to standard care. High-sensitivity C-reactive protein was measured at baseline and at end of study in 5243 patients from dal-OUTCOMES also genotyped for the rs1967309 polymorphism in adenylate cyclase 9. Cholesterol efflux capacity of high-density lipoproteins from J774 macrophages after cAMP stimulation was determined at baseline and 12 months in 171 genotyped patients from dal-PLAQUE-2. Treatment with dalcetrapib resulted in placebo-adjusted geometric mean percent increases in high-sensitivity C-reactive protein from baseline to end of trial of 18.1% (P=0.0009) and 18.7% (P=0.00001) in participants with the GG and AG genotypes, respectively, but the change was -1.0% (P=0.89) in those with the protective AA genotype. There was an interaction between the treatment arm and the genotype groups (P=0.02). Although the mean change in cholesterol efflux was similar among study arms in patients with GG genotype (mean: 7.8% and 7.4%), increases were 22.3% and 3.5% with dalcetrapib and placebo for those with AA genotype (P=0.005). There was a significant genetic effect for change in efflux for dalcetrapib (P=0.02), but not with placebo.

CONCLUSIONS

Genotype-dependent effects on C-reactive protein and cholesterol efflux are supportive of dalcetrapib benefits on atherosclerotic cardiovascular outcomes in patients with the AA genotype at polymorphism rs1967309.

CLINICAL TRIALS REGISTRATION

ClinicalTrials.gov; Unique Identifiers: NCT00658515 and NCT01059682.

MEK1/2 inhibitors activate macrophage ABCG1 expression and reverse cholesterol transport-An anti-atherogenic function of ERK1/2 inhibition

Expression of ATP-binding cassette transporter G1 (ABCG1), a molecule facilitating cholesterol efflux to HDL, is activated by liver X receptor (LXR). In this study, we investigated if inhibition of ERK1/2 can activate macrophage ABCG1 expression and functions. MEK1/2 inhibitors, PD98059 and U0126, increased ABCG1 mRNA and protein expression, and activated the natural ABCG1 promoter but not the promoter with the LXR responsive element (LXRE) deletion. Inhibition of ABCG1 expression by ABCG1 siRNA did enhance the formation of macrophage/foam cells and it attenuated the inhibitory effect of MEK1/2 inhibitors on foam cell formation. MEK1/2 inhibitors activated macrophage cholesterol efflux to HDL in vitro, and they enhanced reverse cholesterol transport (RCT) in vivo. ApoE deficient (apoE(-/-)) mice receiving U0126 treatment had reduced sinus lesions in the aortic root which was associated with activated macrophage ABCG1 expression in the lesion areas. MEK1/2 inhibitors coordinated the RXR agonist, but not the LXR agonist, to induce ABCG1 expression. Furthermore, induction of ABCG1 expression by MEK1/2 inhibitors was associated with activation of SIRT1, a positive regulator of LXR activity, and inactivation of SULT2B1 and RIP140, two negative regulators of LXR activity. Taken together, our study suggests that MEK1/2 inhibitors activate macrophage ABCG1 expression/RCT, and inhibit foam cell formation and lesion development by multiple mechanisms, supporting the concept that ERK1/2 inhibition is anti-atherogenic.

Caveolae and Caveolin-1 Integrate Reverse Cholesterol Transport and Inflammation in Atherosclerosis

Lipid disorder and inflammation play critical roles in the development of atherosclerosis. Reverse cholesterol transport is a key event in lipid metabolism. Caveolae and caveolin-1 are in the center stage of cholesterol transportation and inflammation in macrophages. Here, we propose that reverse cholesterol transport and inflammation in atherosclerosis can be integrated by caveolae and caveolin-1.

Remodeling of plasma lipoproteins in patients with rheumatoid arthritis: Interleukin-6 receptor-alpha inhibition with tocilizumab

PURPOSE

Rheumatoid arthritis (RA) is associated with increased cardiovascular risk, mediated in part by elevated circulating interleukin-6 levels and proinflammatory changes in plasma lipoproteins. We hypothesized that RA patients acquire inflammation-induced modifications to the protein cargo of circulating lipoproteins that may be reversed by tocilizumab, an interleukin-6 receptor-alpha inhibitor.

EXPERIMENTAL DESIGN

Size-exclusion chromatography and reverse-phase protein arrays using 29 antibodies against 26 proteins were applied at baseline and after tocilizumab treatment to analyze the distributions of apolipoproteins, enzymes, lipid transfer proteins, and other associated proteins in plasma lipoprotein fractions from 20 women with RA.

RESULTS

A 30% reduction in high-density lipoprotein (HDL)-associated serum amyloid A4 and complement C4 occurred with tocilizumab. Levels of C-reactive protein, associated or comigrating with HDL and low-density lipoprotein (LDL) peaks, were reduced on treatment by approximately 80% and 24%, respectively. Reductions in lipoprotein-associated phospholipase A2, lipoprotein (a), and cholesteryl ester transfer protein in the LDL fraction suggest reductions in LDL-associated proatherogenic factors. Elevations in very low-density lipoprotein (VLDL) enriched with apolipoprotein E were equally observed.

CONCLUSIONS AND CLINICAL RELEVANCE

Tocilizumab treatment led to reductions in proinflammatory components and proatherogenic proteins associated with HDL. Whether changes in the proteome of VLDL, LDL, and HDL induced by anti-inflammatory tocilizumab treatment in RA patients modify cardiovascular disease risk requires further investigation.

Endothelin-1 impairs coronary arteriolar dilation: Role of p38 kinase-mediated superoxide production from NADPH oxidase

Elevated levels of endothelin-1 (ET-1), a potent vasoactive peptide, are implicated as a risk factor for cardiovascular diseases by exerting vasoconstriction. The aim of this study was to address whether ET-1, at sub-vasomotor concentrations, elicits adverse effects on coronary microvascular function. Porcine coronary arterioles (50-100μm) were isolated, cannulated and pressurized without flow for in vitro study. Diameter changes were recorded using a videomicrometer. Arterioles developed basal tone (60±3μm) and dilated to the endothelium-dependent nitric oxide (NO)-mediated vasodilators serotonin (1nmol/L to 0.1μmol/L) and adenosine (1nmol/L to 10μmol/L). Treating the vessels with a clinically relevant sub-vasomotor concentration of ET-1 (10pmol/L, 60min) significantly attenuated arteriolar dilations to adenosine and serotonin but not to endothelium-independent vasodilator sodium nitroprusside. The arteriolar wall contains ETA receptors and the adverse effect of ET-1 was prevented by ETA receptor antagonist BQ123, the superoxide scavenger Tempol, the NADPH oxidase inhibitors apocynin and VAS2870, the NOX2-based NADPH oxidase inhibitor gp91 ds-tat, or the p38 kinase inhibitor SB203580. However, ETB receptor antagonist BQ788, H2O2 scavenger catalase, scrambled gp91 ds-tat, or inhibitors of xanthine oxidase (allopurinol), PKC (Gö 6983), Rho kinase (Y27632), and c-Jun N-terminal kinase (SP600125) did not protect the vessel. Immunohistochemical staining showed that ET-1 elicited Tempol-, apocynin- and SB203580-sensitive superoxide productions in the arteriolar wall. Our results indicate that exposure of coronary arterioles to a pathophysiological, sub-vasomotor concentration of ET-1 leads to vascular dysfunction by impairing endothelium-dependent NO-mediated dilation via p38 kinase-mediated production of superoxide from NADPH oxidase following ETA receptor activation.

Egg intake during carbohydrate restriction alters peripheral blood mononuclear cell inflammation and cholesterol homeostasis in metabolic syndrome

Egg yolk contains bioactive components that improve plasma inflammatory markers and HDL profiles in metabolic syndrome (MetS) under carbohydrate restriction. We further sought to determine whether egg yolk intake affects peripheral blood mononuclear cell (PBMC) inflammation and cholesterol homeostasis in MetS, as HDL and its associated lipid transporter ATP-binding cassette transporter A1 (ABCA1) reduce the inflammatory potential of leukocytes through modulation of cellular cholesterol content and distribution. Thirty-seven men and women classified with MetS consumed a moderate carbohydrate-restricted diet (25%–30% of energy) for 12 weeks, in addition to consuming either three whole eggs per day (EGG) or the equivalent amount of yolk-free egg substitute (SUB). Interestingly, lipopolysaccharide-induced PBMC IL-1β and TNFα secretion increased from baseline to week 12 in the SUB group only, despite increases in PBMC toll-like receptor 4 (TLR4) mRNA expression in the EGG group. Compared to baseline, ABCA1 and 3-hydroxy-3-methyl-glutaryl (HMG)-CoA reductase mRNA expression increased by week 12 in the EGG group only, whereas changes in PBMC total cholesterol positively correlated with changes in lipid raft content. Together, these findings suggest that intake of whole eggs during carbohydrate restriction alters PBMC inflammation and cholesterol homeostasis in MetS.

Relationship between serum cholesterol efflux capacity and glucose intolerance in Japanese-Americans

AIM

Serum cholesterol efflux has been suggested to be a key anti-atherogenic function of reverse cholesterol transport. Meanwhile, the quantitative and qualitative alteration of the levels of lipoproteins in the serum has been reported in patients with diabetes, although it remains unclear whether the serum cholesterol efflux capacity is impaired in cases of newly diagnosed glucose intolerance. We thus assessed the relationship between the serum cholesterol efflux capacity and glucose intolerance as detected using oral glucose tolerance tests (OGTTs).

METHODS

We measured the capacity of whole serum to mediate cholesterol efflux from human THP-1 macrophages in a cohort of 439 Japanese-Americans who underwent 75-g OGTTs. A multiple regression analysis was performed to examine the relationship between the serum cholesterol efflux capacity and glucose intolerance.

RESULTS

The serum cholesterol efflux capacity was found to be negatively correlated with the area under the curve for the serum glucose concentration during the 75-g OGTTs in all subjects. In addition, the serum cholesterol efflux capacity was found to be modestly but significantly lower in the glucose intolerance group (31.4 ± 6.2%) than in the normal glucose tolerance group (33.2 ± 6.1%). There was also a negative association between the serum cholesterol efflux capacity and glucose intolerance after adjusting for age and sex. Moreover, this association remained significant even after further adjustments for serum total cholesterol, high-density lipoprotein cholesterol, apolipoprotein AI and C-reactive protein.

CONCLUSIONS

The serum cholesterol efflux capacity is impaired in Japanese-Americans newly diagnosed with glucose intolerance. This impairment may contribute in some manner to increasing the risk of atherosclerotic disease in subjects with glucose intolerance.

Cardiovascular risk in rheumatoid arthritis: recent advances in the understanding of the pivotal role of inflammation, risk predictors and the impact of treatment

Risk of cardiovascular (CV) disease is increased among RA patients. High inflammatory burden associated with RA appears to be a key driver of the increased cardiovascular risk. Inflammation is linked with accelerated atherosclerosis and associated with a paradoxical inversion of the relationship between CV risk and lipid levels in patients with untreated RA, recently coined the lipid paradox. Furthermore, the inflammatory burden is also associated with qualitative as well as quantitative changes in lipoproteins, with the anti-inflammatory and atheroprotective roles associated with high-density lipoprotein cholesterol significantly altered. RA therapies can increase lipid levels, which may reflect the normalization of lipids due to their inflammatory-dampening effects. However, these confounding influences of inflammation and RA therapies on lipid profiles pose challenges for assessing CV risk in RA patients and interpretation of traditional CV risk scores. In this review we examine the relationship between the increased inflammatory burden in RA and CV risk, exploring how inflammation influences lipid profiles, the impact of RA therapies and strategies for identifying and monitoring CV risk in RA patients aimed at improving CV outcomes.

Effects of Chinese Herbal Compound "Xuemai Ning"on Rabbit Atherosclerosis Model and Expression of ABCA1

OBJECTIVE

To observe the lipid and the pathological changes of carotid artery smooth muscle cells in atherosclerotic rabbits, verification of Chinese herbal compound which has improve blood lipid and anti atherosclerosis effects, focus on ABCA1 as the key receptor which participated in reverse cholesterol transport, to study the mechanism of Chinese herbal compound (Xuemai Ning).

MATERIALS AND METHODS

30 rabbits were randomly divided into blank group, model group and Chinese herbal compound (Xuemai Ning) group, The model group and the Xuemai Ning group with high fat diet and injection of vitamin D3, causing atherosclerosis model 4 weeks after the intervention of traditional Chinese medicine group, In the 4th week after Xuemai Ning group received the intervention of Chinese herbal compound. Blood lipid, the carotid artery pathological changes and expression of ABCA1 gene and protein in peritoneal macrophage surface were detected after 8 weeks.

RESULTS

The carotid artery atherosclerotic plaque formation of the model group was obvious, the carotid atherosclerotic changes of the Xuemai Ning group rabbit significantly lighter than the model group. The serum lipid of model group and Xuemai Ning group were higher than that of the blank group; and the traditional Chinese medicine can up the expression of ABCA1 protein, higher than those in the model group. Expression of macrophage ABCA1 in model group was significantly up regulated at protein level higher than the blank group; and the traditional Chinese medicine can up regulate the expression of ABCA1 protein, higher than those in the model group. Expression of ABCA1 mRNA was significantly up regulated in model group, ABCA1 mRNA of Xuemai Ning group raised more significantly.

CONCLUSION

Xuemai Ning can reduce triglyceride, total cholesterol and low density lipoprotein of hyperlipidemia model in rabbits serum, increase high density lipoprotein, remove foam cells in atherosclerotic cells, improve pathological of AS and up-regulate ABCA1 gene and protein so as to effectively inhibit atherosclerotic disease.

Egg consumption modulates HDL lipid composition and increases the cholesterol-accepting capacity of serum in metabolic syndrome

We recently demonstrated that daily whole egg consumption during moderate carbohydrate restriction leads to greater increases in plasma HDL-cholesterol (HDL-C) and improvements in HDL profiles in metabolic syndrome (MetS) when compared to intake of a yolk-free egg substitute. We further investigated the effects of this intervention on HDL composition and function, hypothesizing that the phospholipid species present in egg yolk modulate HDL lipid composition to increase the cholesterol-accepting capacity of subject serum. Men and women classified with MetS were randomly assigned to consume either three whole eggs (EGG, n = 20) per day or the equivalent amount of egg substitute (SUB, n = 17) throughout a 12-week moderate carbohydrate-restricted (25-30 % of energy) diet. Relative to other HDL lipids, HDL-cholesteryl ester content increased in all subjects, with greater increases in the SUB group. Further, HDL-triacylglycerol content was reduced in EGG group subjects with normal baseline plasma HDL-C, resulting in increases in HDL-CE/TAG ratios in both groups. Phospholipid analysis by mass spectrometry revealed that HDL became enriched in phosphatidylethanolamine in the EGG group, and that EGG group HDL better reflected sphingomyelin species present in the whole egg product at week 12 compared to baseline. Further, macrophage cholesterol efflux to EGG subject serum increased from baseline to week 12, whereas no changes were observed in the SUB group. Together, these findings suggest that daily egg consumption promotes favorable shifts in HDL lipid composition and function beyond increasing plasma HDL-C in MetS.

The transcription levels of ABCA1, ABCG1 and SR-BI are negatively associated with plasma CRP in Chinese populations with various risk factors for atherosclerosis

ATP binding cassette transporters (ABCA1, ABCG1) and scavenger receptor class B type I (SR-BI) are the three most important cellular cholesterol transporters that may prevent atherogenesis. The aim of this study was to investigate whether they were altered in Chinese populations with various risk factors for atherosclerosis and their potential associations with C-reactive protein (CRP). Healthy female controls (n = 30) and populations with various risk factors for atherosclerosis, such as type 2 diabetes (n = 17), hypertension (n = 12), overweight/obesity (n = 10), incipient nephropathy (n = 10), postmenopausal women (n = 9), male (n = 19), ageing male (n = 22), or smoking (n = 16), were recruited. ABCA1, ABCG1 and SR-BI mRNA levels in peripheral monocytes was determined. ABCG1 was decreased in all the risk populations except ageing. ABCA1 was decreased in all the risk populations except diabetes and male. SR-BI was decreased in those with overweight/obesity and incipient nephropathy. Circulating CRP was increased almost in all the risk populations except in males. The levels of ABCA1, ABCG1 and SR-BI were reduced in those with subclinically high CRP, and negatively associated with CRP level. These data indicates that ABCA1, ABCG1, and SR-BI are reduced in various populations under subclinically inflammatory conditions, which may potentially lead to impairing reverse cholesterol transport and developing atherosclerosis.

Tamoxifen alters the plasma concentration of molecules associated with cardiovascular risk in women with breast cancer undergoing chemotherapy

OBJECTIVES

The objective of this study was to evaluate the effect of tamoxifen on blood markers that are associated with cardiovascular risk, such as C-reactive protein (CRP), apolipoprotein A-1 (Apo-A), and apolipoprotein B-100 (Apo-B), in women undergoing chemotherapy for breast cancer.

METHODS

Over a period of 12 months, we followed 60 women with breast cancer. The women were divided into the following groups: a group that received only chemotherapy (n = 23), a group that received chemotherapy plus tamoxifen (n = 21), and a group that received only tamoxifen (n = 16). Plasma CRP levels were assessed at 0, 3, 6, and 12 months, and Apo-A and Apo B levels as well as the Apo-B/Apo-A ratio were assessed at 0 and 12 months.

RESULTS

We found increases in the plasma concentration of CRP in the chemotherapy alone and chemotherapy plus tamoxifen groups after 3 and 6 months of treatment (before the introduction of tamoxifen). However, after 12 months of treatment, women who used tamoxifen (the chemotherapy plus tamoxifen and tamoxifen alone groups) showed a significant reduction in CRP and Apo-B levels and a decrease in the Apo-B/Apo-A ratio. A significant increase in serum Apo-A levels was observed in the group receiving chemotherapy alone as a treatment for breast cancer.

CONCLUSION

The use of tamoxifen after chemotherapy for the treatment of breast cancer significantly reduces the levels of cardiovascular disease risk markers (CRP, Apo-B, and the Apo-B/Apo-A ratio).

Apolipoprotein A-I, apolipoprotein B, high-sensitivity C-reactive protein and severity of coronary artery disease in Tunisian population

BACKGROUND

The relationship between Apolipoprotein A-I, Apolipoprotein B, C-reactive protein and the severity coronary artery disease in Tunisian CAD patients has not been examined. We investigated the association between serum ApoA-I, ApoB, hs-CRP and the severity of coronary artery disease.

METHODS

This study was carried out on 180 patients who underwent angiography and 129 healthy controls. ApoA-I and ApoB as well as the serum total cholesterol, HDL, triglyceride, LDL and hs-CRP levels were measured. The ApoB/ApoA-I ratio was calculated.

RESULTS

We showed a decreased level of ApoA-I and an increased level of ApoB, ApoB/ApoA-I ratio and hs-CRP in CAD patients compared to the control group (P<.001). In addition, we showed a significant increase of ApoB, ApoB/ApoA-I ratio and hs-CRP in CAD patients presenting 0 to 3 vessels stenosis (P<.001). Multivariate analysis showed that ApoB (P<.001), and hs-CRP (P<.001) were independent predictors of the severity of CAD.

CONCLUSION

In this study, ApoB and hs-CRP levels were markedly associated with the severity of CAD in Tunisian patients. We suggested that synergistic effects between dyslipidemia and inflammation led to increase the risk of the severity of CAD.

ApoA-1 mimetic restores adiponectin expression and insulin sensitivity independent of changes in body weight in female obese mice

BACKGROUND

We examined the ability of the apolipoprotein AI mimetic peptide L-4F to improve the metabolic state of female and male ob mice and the mechanisms involved.

METHODS

Female and male lean and obese (ob) mice were administered L-4F or vehicle for 6 weeks. Body weight was measured weekly. Fat distribution, serum cytokines and markers of cardiovascular dysfunction were determined at the end of treatment.

RESULTS

L-4F significantly decreased serum interleukin (IL)-6, tumor necrosis factor-α and IL-1β. L-4F improved vascular function, and increased serum adiponectin levels and insulin sensitivity compared with untreated mice. In addition, L-4F treatment increased heme oxygenase (HO)-1, pAKT and pAMPK levels in kidneys of ob animals. pAKT and pAMPK levels were significantly reduced in the presence of an HO inhibitor. Interestingly, L4F did not alter body weight in female mice, but caused a significant reduction in males.

CONCLUSIONS

L-4F treatments reduced cardiovascular risk factors and improved insulin sensitivity in female ob mice independent of body fat changes. Reduced inflammatory cytokine levels accompanied by increased HO activity, serum adiponectin and improved insulin sensitivity suggest that L-4F may promote the conversion of visceral fat to a healthier phenotype. Therefore, L-4F appears to be a promising therapeutic strategy for treating both cardiovascular risk factors and insulin resistance in obese patients of either gender.

Walnut oil increases cholesterol efflux through inhibition of stearoyl CoA desaturase 1 in THP-1 macrophage-derived foam cells

Background

Walnuts significantly decrease total and low-density lipoprotein cholesterol in normo- and hypercholesterolemic individuals. No study to date has evaluated the effects of walnuts on cholesterol efflux, the initial step in reverse cholesterol transport, in macrophage-derived foam cells (MDFC). The present study was conducted to investigate the mechanisms by which walnut oil affects cholesterol efflux.

Methods

The extract of English walnuts (walnut oil) was dissolved in DMSO and applied to cultured THP-1 MDFC cells (0.5 mg/mL). THP-1 MDFC also were treated with human sera (10%, v:v) taken from subjects in a walnut feeding study. Cholesterol efflux was examined by liquid scintillation counting. Changes in gene expression were quantified by real time PCR.

Results

Walnut oil treatment significantly increased cholesterol efflux through decreasing the expression of the lipogenic enzyme stearoyl CoA desaturase 1 (SCD1) in MDFC. Alpha-linolenic acid (ALA), the major n-3 polyunsaturated fatty acids found in walnuts, recaptured SCD1 reduction in MDFC, a mechanism mediated through activation of nuclear receptor farnesoid-X-receptor (FXR). Postprandial serum treatment also increased cholesterol efflux in MDFC. When categorized by baseline C-reactive protein (CRP; cut point of 2 mg/L), subjects in the lower CRP sub-group benefited more from dietary intervention, including a more increase in cholesterol efflux, a greater reduction in SCD1, and a blunted postprandial lipemia.

Conclusion

In conclusion, walnut oil contains bioactive molecules that significantly improve cholesterol efflux in MDFC. However, the beneficial effects of walnut intake may be reduced by the presence of a pro-inflammatory state.

Trial Registration

ClinicalTrials.gov: NCT00938340

Metabolic nuclear receptor signaling and the inflammatory acute phase response

The acute phase response (APR) classically refers to the rapid reprogramming of gene expression and metabolism in response to inflammatory cytokine signaling. As components of the innate immune system, hepatocyte-derived acute phase proteins (APPs) play a central role in restoring tissue homeostasis. Recently, an intriguing 'metaflammatory' facet of the APR became evident with chronically elevated APP levels being connected to metabolic syndrome disorders. The causality of these connections is unclear but could relate to adverse metabolic and inflammatory disturbances, particularly those affecting lipoprotein properties, cholesterol metabolism and atherogenesis. Here we review these aspects with an emphasis on the emerging importance of lipid-sensing nuclear receptors (LXRs, LRH-1, PPARs), in conjunction with anti-inflammatory transrepression pathways, as physiological and pharmacological relevant modulators of the APR.

Role of C-reactive protein in contributing to increased cardiovascular risk in metabolic syndrome

Metabolic syndrome is associated with increased propensity for diabetes and cardiovascular disease. Low-grade inflammation is characteristic of metabolic syndrome. C-reactive protein, the best characterized biomarker of inflammation, is also an independent predictor of future cardiovascular events. This review outlines the role of high-sensitivity C-reactive protein in contributing to increased cardiovascular risk in metabolic syndrome by inducing endothelial cell dysfunction and activating monocytes.

Relative roles of various efflux pathways in net cholesterol efflux from macrophage foam cells in atherosclerotic lesions

PURPOSE OF REVIEW

Cholesterol efflux mechanisms are essential for macrophage cholesterol homeostasis. HDL, an important cholesterol efflux acceptor, comprises a class of heterogeneous particles that induce cholesterol efflux via distinct pathways. This review focuses on the understanding of the different cholesterol efflux pathways and physiological acceptors involved, and their regulation in atherosclerotic lesions.

RECENT FINDINGS

The synergistic interactions of ATP-binding cassette transporters A1 and G1 as well as ATP-binding cassette transporter A1 and scavenger receptor class B type I are essential for cellular cholesterol efflux and the prevention of macrophage foam cell formation. However, the importance of aqueous diffusion should also not be underestimated. Significant progress has been made in understanding the mechanisms underlying ATP-binding cassette A1-mediated cholesterol efflux and regulation of its expression and trafficking. Conditions locally in the atherosclerotic lesion, for example, lipids, cytokines, oxidative stress, and hypoxia, as well as systemic factors, including inflammation and diabetes, critically influence the expression of cholesterol transporters on macrophage foam cells. Furthermore, HDL modification and remodeling in atherosclerosis, inflammation, and diabetes impairs its function as an acceptor for cellular cholesterol.

SUMMARY

Recent advances in the understanding of the regulation of cholesterol transporters and their acceptors in atherosclerotic lesions indicate that HDL-based therapies should aim to enhance the activity of cholesterol transporters and improve both the quantity and quality of HDL.

C-reactive protein is a bystander of cardiovascular disease

A large number of studies have evaluated the association of hs-C-reactive protein with atherosclerosis and coronary heart disease (CHD) in mechanistic, genetic, population-based studies, as well as clinical trials. This paper reviews the collective evidence to determine if hs-C-reactive protein is part of the causal pathway of atherosclerosis and CHD or whether it is a bystander.

ATP-binding membrane cassette transporter A1 (ABCA1): a possible link between inflammation and reverse cholesterol transport

Atherosclerosis is characterized by a chronic inflammatory condition that involves numerous cellular and molecular inflammatory components. A wide array of inflammatory mediators, such as cytokines and proteins produced by macrophages and other cells, play a critical role in the development and progression of the disease. ATP-binding membrane cassette transporter A1 (ABCA1) is crucial for cellular cholesterol efflux and reverse cholesterol transport (RCT) and is also identified as an important target in antiatherosclerosis treatment. Evidence from several recent studies indicates that inflammation, along with other atherogenic-related mediators, plays distinct regulating roles in ABCA1 expression. Proatherogenic cytokines such as interferon (IFN)-γ and interleukin (IL)-1β have been shown to inhibit the expression of ABCA1, while antiatherogenic cytokines, including IL-10 and transforming growth factor (TGF)-β1, have been shown to promote the expression of ABCA1. Moreover, some cytokines such as tumor necrosis factor (TNF)-α seem to regulate ABCA1 expression in species-specific and dose-dependent manners. Inflammatory proteins such as C-reactive protein (CRP) and cyclooxygenase (COX)-2 are likely to inhibit ABCA1 expression during inflammation, and inflammation induced by lipopolysaccharide (LPS) was also found to block the expression of ABCA1. Interestingly, recent experiments revealed ABCA1 can function as an antiinflammatory receptor to suppress the expression of inflammatory factors, suggesting that ABCA1 may be the molecular basis for the interaction between inflammation and RCT. This review aims to summarize recent findings on the role of inflammatory cytokines, inflammatory proteins, inflammatory lipids, and the endotoxin-mediated inflammatory process in expression of ABCA1. Also covered is the current understanding of the function of ABCA1 in modulating the immune response and inflammation through its direct and indirect antiinflammatory mechanisms including lipid transport, high-density lipoprotein (HDL) formation and apoptosis.

Inflammation and dyslipidaemia: a possible interplay between established risk factors in North Indian males with coronary artery disease

OBJECTIVES

Coronary artery disease (CAD) is a leading cause of morbidity and mortality in the developed world and is rapidly assuming epidemic proportions in developing countries, including India. This has led to extensive research to determine the risk factors and the pathways that may predispose to the elevated risk of this disease. Important among them include lipoproteins, homocysteine, lipoprotein (a), pro-inflammatory cytokines and others. The following study was undertaken to determine a possible inter-relationship between inflammation and dyslipidaemia, which are important risk factors for CAD in the atherosclerosis-prone North Indian male population.

METHODS

The study groups comprised 150 clinically assessed North Indian male patients with acute myocardial infarction (AMI), diagnosed on electrocardiographic and biochemical criteria, and 150 healthy controls. Apolipoprotein-AI (Apo-AI), apolipoprotein-B (Apo-B) and C-reactive protein (CRP) levels were estimated using kits based on the immunoturbidimetric assay from Randox, UK. Tumour necrosis factor-alpha (TNF-alpha) and lipoprotein (a) were assayed using commercially available ELISA kits from Diaclone Research, Belgium and Innogenetics, Belgium, respectively.

RESULTS

The patients with AMI showed highly significant elevations in the levels of total serum cholesterol, triglycerides, LDL cholesterol, Apo-B and a significant decline in HDL cholesterol, compared with healthy controls. Significantly elevated serum levels of inflammatory markers, TNF-alpha and CRP were seen in patients with AMI, compared to the control subjects. A significantly positive correlation of TNF-alpha was observed with lipoprotein (a) in patients with CAD.

CONCLUSION

The data clearly underlines a possible interplay between inflammation and dyslipidaemia in the pathogenesis of CAD in the Indian context. This insight into the aetiopathogenesis of CAD will prove highly beneficial for devising better preventive measures and pharmacological interventions for CAD.

Vitamin E decreases endogenous cholesterol synthesis and apo-AI-mediated cholesterol secretion in Caco-2 cells

Intestine is the gateway for newly absorbed tocopherols. This organ also plays a crucial role in cholesterol metabolism. Because tocopherols are known to impact cholesterol metabolism in the liver, we hypothesized that tocopherols could also modulate cholesterol metabolism in the intestine. This study aimed to verify this hypothesis and to unveil the mechanisms involved, using Caco-2 cells as a model of the human intestinal cell. Both α- and γ-tocopherol significantly (P<.05) decreased endogenous cholesterol synthesis and apo-AI-mediated cholesterol secretion in Caco-2 cells. Tocopherols down-regulated (P<.05) up to half of the genes involved in the cholesterol synthesis pathway, together with CYP27A1, which is involved in oxysterol production. The activity of this enzyme, as well as the levels of intracellular oxysterols, was significantly diminished by tocopherols. Finally, tocopherols significantly reduced ABCA1 mRNA levels in Caco-2 cells. We conclude that tocopherols impair the endogenous synthesis and apo-AI-mediated secretion of cholesterol in Caco-2 cells. This effect involves a down-regulation of genes involved in the cholesterol synthesis pathway, resulting in down-regulation of CYP27A1 which, in turn, diminishes oxysterol concentrations. The outcome is a decrease of LXR activity, resulting in down-regulation of ABCA1. These data reinforce the effect of α- and γ-tocopherol on cholesterol metabolism via gene expression regulation.