Association of remnant lipoprotein levels with impairment of endothelium-dependent vasomotor function in human coronary arteries

Association of remnant cholesterol and lipid parameters with new-onset carotid plaque in Chinese population

Background

Remnant lipoprotein cholesterol (RC) is an independent risk factor for cardiovascular disease (CVD). However, the relationships of remnant cholesterol and other conventional lipid parameters with new-onset carotid plaque are not fully understood in the Chinese community-based population.

Materials and methods

A total of 872 plaque-free participants (51.39 ± 4.96 years old) with no history of CVD were included in this study. The plasma concentrations of RC were calculated by subtracting low-density lipoprotein cholesterol (LDL-C) and high-density lipoprotein cholesterol (HDL-C) from total cholesterol (TC). Multivariate regression models were used to evaluate and compare the associations between RC and other lipid parameters and new-onset carotid plaque.

Results

After a mean 6.77-year follow-up, the incidence of new-onset carotid plaque was 188 (21.56%). RC was significantly associated with new-onset carotid plaque [Odd ratio (OR) = 1.57 per 1 mmol/L increase, 95% confidence interval (CI): 1.03–2.41, p = 0.038]. The highest tertile of RC (T3 group) had the highest risk of new-onset carotid plaque (OR = 2.53, 95% CI: 1.63–3.95). Similar results were seen for increased other lipid parameters, but decreased HDL-C levels. When adding another lipid parameter into the adjusted model with RC simultaneously, only RC remained significantly associated with new-onset carotid plaque after adjusting for other lipid parameters (all p value < 0.005). Furthermore, RC was strongly associated with new-onset carotid plaque in participants with lower baseline LDL-C levels.

Conclusion

Increased RC levels were superior to other conventional lipid parameters to be associated with new-onset carotid plaque in the Chinese community-based population. Furthermore, RC should be considered in participants with lower LDL-C levels for the purpose of early atherosclerosis prevention.

Association of triglyceride-rich lipoprotein-cholesterol with recurrent cardiovascular events in statin-treated patients according to different inflammatory status

BACKGROUND AND AIMS

The association of triglyceride-rich lipoprotein-cholesterol (TRL-C) with recurrent cardiovascular events (RCVEs) has not been studied. Moreover, whether inflammation can affect TRL-C-associated cardiovascular risk is unknown. This study sought to examine the association between TRL-C and RCVEs, and whether this relationship is modulated by systemic inflammation in statin-treated patients with coronary artery disease (CAD) and nearly normal triglyceride.

METHODS

In this study, 6723 CAD patients were consecutively enrolled, following a first CVE with triglyceride <2.3 mmol/L. Baseline lipid profile and high-sensitivity C-reactive protein (hsCRP) levels were determined. All patients were searched for RCVEs. The risk of RCVEs was assessed across quartiles (Q) of baseline TRL-C and further stratified by the median of hsCRP.

RESULTS

Over a mean follow-up of 58.91 ± 17.79 months, 538 RCVEs were recorded. After adjustment for potential confounders, Q4 of TRL-C was significantly associated with the risk of RCVEs, which remained unchanged after hsCRP stratification. When subjects were grouped according to both TRL-C and hsCRP levels, patients with Q4 of TRL-C and hsCRP had the highest increase of the risk of RCVEs compared with the reference group (TRL-C Q1-3 and hsCRP Q1-3; HR, 1.90; 95%CI: 1.27-2.87). Furthermore, adding TRL-C to the original predicting model led to a slight but significant improvement.

CONCLUSIONS

The present analysis firstly showed that elevated TRL-C was associated with an increased RCVEs risk in statin-treated patients with CAD independent of systemic inflammation, suggesting that it might be a useful marker for risk stratification and a treatment target in this patient population.

GLP-1 (Glucagon-Like Peptide-1) Is Physiologically Relevant for Chylomicron Secretion Beyond Its Known Pharmacological Role

[Figure: see text].

Impact of persistent endothelial dysfunction in an infarct-related coronary artery on future major adverse cardiovascular event occurrence in STEMI survivors

Although coronary endothelial vasomotor dysfunction predicts future coronary events, few human studies have shown the relationship between persistent endothelial vasomotor dysfunction and major adverse cardiovascular events (MACE) using serial assessments in the same coronary artery. This study examined whether persistent endothelial vasomotor dysfunction is related to MACE occurrence in the infarct-related coronary artery (IRA) of ST-segment elevation myocardial infarction (STEMI) survivors using serial assessments of the coronary vasomotor response to acetylcholine (ACh). This study included 169 consecutive patients with a first acute STEMI due to left anterior descending coronary artery (LAD) occlusion and successful reperfusion therapy with percutaneous coronary intervention. Vasomotor response to ACh in the LAD was measured within 2 weeks of acute myocardial infarction (AMI) (first test) and repeated 6 months (second test) after AMI under optimal anti-atherosclerotic therapy. MACE was defined as the composite of all-cause death, non-fatal MI, angina recurrence requiring percutaneous intervention or surgical bypass, and hospitalization for heart failure. We followed up 126 patients for a period of ≤ 60 months until MACE occurrence after second test. Nineteen MACEs occurred during the follow-up. The log-rank test, Kaplan-Meier curves and univariate Cox proportional hazards regression analysis showed that MACE occurrence was significantly associated with the persistent impairment of epicardial coronary artery dilation and coronary blood flow increases in response to ACh (log-rank test, p < 0.001 and p < 0.001, respectively) (Hazard ratio, p = 0.001 and p = 0.002, respectively). Persistent impairment of endothelial vasomotor function in the infarct-related conduit arterial segment and resistance arteriole were the significant predictor of future MACE occurrence in STEMI survivors.

Prognostic impact of estimated remnant-like particle cholesterol in patients with differing glycometabolic status: an observational cohort study from China

Background

It is uncertain whether estimated remnant-like particle cholesterol (RLP-C) could predict residual risk in patients with different glycometabolic status. This study aimed to evaluate the relationship between estimated RLP-C and adverse prognosis in patients with non-ST-segment elevation acute coronary syndrome (NSTE-ACS) treated with percutaneous coronary intervention (PCI) and to identify the potential impact of glycometabolism on the predictive value of estimated RLP-C.

Methods

The study assessed 2419 participants with NSTE-ACS undergoing PCI at Beijing Anzhen Hospital from January to December 2015. Estimated RLP-C was calculated as follows: total cholesterol (TC) minus low-density lipoprotein cholesterol (LDL-C) and high-density lipoprotein cholesterol (HDL-C). The adverse events included all-cause death, non-fatal myocardial infarction (MI), and ischemia-driven revascularization.

Results

Estimated RLP-C was prominently associated with adverse prognosis in the total population [hazard ratio (HR) 1.291 per 1-SD increase, 95% confidence interval (CI) 1.119–1.490, P <  0.001], independent of confounding risk factors. However, subgroup analysis showed that increasing estimated RLP-C was related to a higher risk of adverse events in the diabetic population only [HR 1.385 per 1-SD increase, 95% CI 1.183–1.620, P <  0.001]. Estimated RLP-C failed to be a significant determinant of adverse prognosis in non-diabetic and pre-diabetic subgroups. The addition of estimated RLP-C to a baseline model including traditional risk factors enhanced the predictive performance both in total and diabetic populations.

Conclusions

High estimated RLP-C level is a significant predictor for recurrent adverse events in patients with diabetes and NSTE-ACS treated with PCI.

Variation in Coronary Atherosclerosis Severity Related to a Distinct LDL (Low-Density Lipoprotein) Profile: Findings From a Familial Hypercholesterolemia Pig Model

OBJECTIVE

In an adult porcine model of familial hypercholesterolemia (FH), coronary plaque development was characterized. To elucidate the underlying mechanisms of the observed inter-individual variation in disease severity, detailed lipoprotein profiles were determined. Approach and Results: FH pigs (3 years old, homozygous LDLR R84C mutation) received an atherogenic diet for 12 months. Coronary atherosclerosis development was monitored using serial invasive imaging and histology. A pronounced difference was observed between mildly diseased pigs which exclusively developed early lesions (maximal plaque burden, 25% [23%-34%]; n=5) and advanced-diseased pigs (n=5) which developed human-like, lumen intruding plaques (maximal plaque burden, 69% [57%-77%]) with large necrotic cores, intraplaque hemorrhage, and calcifications. Advanced-diseased pigs and mildly diseased pigs displayed no differences in conventional risk factors. Additional plasma lipoprotein profiling by size-exclusion chromatography revealed 2 different LDL (low-density lipoprotein) subtypes: regular and larger LDL. Cholesterol, sphingosine-1-phosphate, ceramide, and sphingomyelin levels were determined in these LDL-subfractions using standard laboratory techniques and high-pressure liquid chromatography mass-spectrometry analyses, respectively. At 3 months of diet, regular LDL of advanced-diseased pigs contained relatively more cholesterol (LDL-C; regular/larger LDL-C ratio 1.7 [1.3-1.9] versus 0.8 [0.6-0.9]; P=0.008) than mildly diseased pigs, while larger LDL contained more sphingosine-1-phosphate, ceramides, and sphingomyelins. Larger and regular LDL was also found in plasma of 3 patients with homozygous FH with varying LDL-C ratios.

CONCLUSIONS

In our adult FH pig model, inter-individual differences in atherosclerotic disease severity were directly related to the distribution of cholesterol and sphingolipids over a distinct LDL profile with regular and larger LDL shortly after the diet start. A similar LDL profile was detected in patients with homozygous FH.

Improvement of endothelial dysfunction is mediated through reduction of remnant lipoprotein after statin therapy in patients with coronary artery disease

BACKGROUND

Remnant lipoproteinemia with high levels of low-density lipoprotein cholesterol (LDL-C) is a high risk for endothelial dysfunction. Statins are the first-line lipid-lowering drugs for this combined hyperlipidemia. However, it remains undetermined whether reduction of remnant lipoprotein mediates the relationship between improvement in endothelial dysfunction and reduction of LDL-C level after statin treatment.

METHODS

A total of 122 coronary artery disease (CAD) patients with impaired flow-mediated dilation (FMD; <5.5%), high levels of LDL-C (≥100 mg/dL), and remnant-like lipoprotein particle cholesterol (RLP-C) (≥5 mg/dL) were examined in this study. The lipid profiles and FMD were measured before and after 6-9 months of statin treatment. The association between changes in LDL-C levels and its relationship with changes in FMD was investigated. Furthermore, mediation analysis was performed to assess the changes in RLP-C level as a mediator of the relationship between the reduction in LDL-C level and improvement of FMD.

RESULTS

Treatment with statins improved FMD in 69 (56.5%) patients. Patients with improved FMD showed lower percent changes of LDL-C, triglyceride (TG), RLP-C, RLP-C/TG, and C-reactive protein (CRP) levels, and higher percent change of HDL-C level, compared to patients who did not show improved FMD. The percent changes in FMD levels had a significant inverse correlation with the percent changes in LDL-C, (r = -0.18, p =  0.03), RLP-C (r = -0.39, p < 0.001), RLP-C/TG (r = -0.34, p < 0.001), and CRP (r = -0.27, p < 0.01). Mediation analysis showed that the relationship between reduction in LDL-C and improvement of FMD was mediated by reduction of RLP-C (34.5%), RLP-C/TG (24.4%), and CRP (24.9%) levels.

CONCLUSION

Improvement of remnant lipoproteinemia may be an important mediator for the relationship between improvement of endothelial dysfunction and LDL-lowering after statin treatment in patients with CAD.

Sustained endothelial dysfunction in the infarct-related coronary artery is associated with left ventricular adverse remodeling in survivors of ST-segment elevation myocardial infarction

BACKGROUND

Ischemia-reperfusion causes endothelial injury and dysfunction in the infarct-related coronary artery (IRA). Using serial assessment of coronary endothelial vasomotor function and left ventriculography (LVG), this study prospectively investigated the clinical impact of endothelial vasomotor dysfunction in the patent IRA on left ventricular (LV) remodeling in survivors of ST-elevation myocardial infarction (STEMI).

METHODS

This study included 78 patients with STEMI due to occlusion of the left anterior descending coronary artery (LAD) and successful reperfusion therapy with percutaneous coronary intervention. All of them had LV ejection fraction (LVEF) <55%. LVG and the vasomotor responses to acetylcholine (ACh) in the LAD were examined within 2 weeks (1st test) and 6 months (2nd test) after MI. Cut-off values for coronary vasomotor dysfunction in response to ACh were based on the lower 10% of the distribution of coronary vasomotor responses to ACh in 20 control subjects.

RESULTS

LV adverse remodeling, defined as a >10% increase in either LV end-diastolic volume index (LVEDVI) and/or end-systolic volume index (LVESVI) from the 1st to the 2nd test, occurred in 21 (70%) of 30 patients with sustained impairment of the coronary flow response to ACh at both the 1st and 2nd tests and 14 (29%) of 48 in the other coronary flow response group (p < 0.01). In multivariate logistic regression analysis, a >10% increase in LVEDVI and LVESVI was respectively associated with sustained impairment of the coronary diameter and flow responses to ACh (OR 4.9 and 3.5, 95% CI 1.7-14.1 and 1.1-10.9, p < 0.01 and p = 0.03, respectively), that was independent of hypertension, peak creatine phosphokinase, and the baseline coronary flow response to ACh at the 1st test.

CONCLUSIONS

Sustained endothelial vasomotor dysfunction in the IRA was associated with LV adverse remodeling in STEMI survivors with successful reperfusion therapy.

Persistent Dysfunction of Coronary Endothelial Vasomotor Responses is Related to Atheroma Plaque Progression in the Infarct-Related Coronary Artery of AMI Survivors

Aim: Although coronary endothelial vasomotor dysfunction predicts future coronary events, there are few human studies showing the relationship between endothelial vasomotor dysfunction and atheroma plaque progression in the same coronary artery. This study examined whether endothelial vasomotor dysfunction is related to atheroma plaque progression in the infarct-related coronary artery of ST-segment elevation myocardial infarction (STEMI) survivors using serial assessment of coronary plaque size with intravascular ultrasound (IVUS) and coronary vasomotor responses to acetylcholine (ACh).

Methods: This study included 50 patients with a first acute STEMI due to occlusion of the left anterior descending coronary artery (LAD) and successful reperfusion therapy with percutaneous coronary intervention (PCI). IVUS and vasomotor response to ACh in the LAD were measured within two weeks of acute myocardial infarction (AMI) (1^st test) and repeated six months (2^nd test) after AMI under optimal anti-atherosclerotic therapies.

Results: Percent atheroma volume (PAV) and total atheroma volume (TAV) in the LAD progressed over six months of follow-up in 18 and 14 patients, respectively. PAV and TAV progression was significantly associated with persistent impairment of epicardial coronary artery dilation and coronary blood flow increase in response to ACh at both the 1^st and 2^nd tests. PAV and TAV progression had no significant association with traditional risk factors, PCI-related variables, medications, and the coronary vasomotor responses to sodium nitroprusside, an endothelium-independent vasodilator.

Conclusions: Persistent impairment of endothelial vasomotor function in the conduit arterial segment and the resistance arteriole was related to atheromatous plaque progression in the infarct-related coronary arteries of STEMI survivors.

Oral Fat Tolerance Test for Sitosterolemia and Familial Hypercholesterolemia: A Study Protocol

AIM

Sitosterolemia is an extremely rare, autosomal recessive disease characterized by high plasma cholesterols and plant sterols because of increased absorption of dietary cholesterols and sterols from the intestine, and decreased excretion from biliary tract. Previous study indicated that sitosterolemic patients might be vulnerable to post-prandial hyperlipidemia, including high remnant-like lipoprotein particles (RLP) level. Here we evaluate whether a loading dietary fat increases a post-prandial RLP cholesterol level in sitosterolemic patients compared to heterozygous familial hypercholesterolemic patients (FH).

METHODS

We recruit total of 20 patients: 5 patients with homozygous sitosterolemia, 5 patients with heterozygous sitosterolemia, and 10 patients with heterozygous FH as controls from May 2015 to March 2018 at Kanazawa University Hospital, Japan. All patients receive Oral Fat Tolerance Test (OFTT) cream (50 g/body surface area square meter, orally only once, and the cream includes 34% of fat, 74 mg of cholesterol, and rich in palmitic and oleic acids. The primary endpoint is the change of a RLP cholesterol level after OFTT cream loading between sitosterolemia and FH. We measure them at baseline, and 2, 4, and 6 hours after the oral fat loading.

RESULTS

This is the first study to evaluate whether sitosterolemia patients have a higher post-prandial RLP cholesterol level compared to heterozygous FH patients.

CONCLUSION

The result may become an additional evidence to restrict dietary cholesterols for sitosterolemia. This study is registered at University Hospital Medical Information Network (UMIN) Clinical Trials Registry (UMIN ID: UMIN000020330).

Development of a Novel Homogeneous Assay for Remnant Lipoprotein Particle Cholesterol

Background

Quantification of remnant lipoprotein particle cholesterol (RLP-C) by automated assay is useful in routine clinical laboratories to assess coronary artery disease risk and diagnose type III hyperlipoproteinemia.

Methods

Enzymes and surfactants were screened to establish a homogeneous RLP-C assay using the chylomicron-VLDL, LDL, and HDL fractions isolated by ultracentrifugation, along with the RLP fraction isolated by immunoaffinity gel. All data were generated using a Hitachi analyzer.

Results

A specific cholesterol esterase with a polyoxyethelene styrenated phenyl ether derivative (surfactant) was used for the establishment of a homogeneous RLP-C assay. This cholesterol esterase with subunits of &gt;40 kDa (H-CE) was found to react with lipoproteins other than RLP, whereas this enzyme with subunits of &lt;40 kDa (L-CE) reacted with RLP. H-CE was applied for the first reaction step with the specific surfactant to decompose non-RLP lipoproteins, degrading non-RLP cholesterol into water and oxygen in the presence of cholesterol oxidase and catalase. For the second step, L-CE was applied to release cholesterol from RLP, and then the released RLP-C was determined in a standard cholesterol oxidase and peroxidase system. This new homogeneous assay exhibited good correlation with the RLP-C immunoseparation method.

Conclusions

We established a simple, rapid, automated homogeneous assay for RLP-C. The assay can determine RLP-C levels in 10 min in a fully automated manner, processing a large number of samples in routine clinical laboratories.

ApoCIII as a Cardiovascular Risk Factor and Modulation by the Novel Lipid-Lowering Agent Volanesorsen

PURPOSE OF REVIEW

Apolipoprotein CIII (ApoCIII) is now recognized as a key regulator in severe hypertriglyceridemia, chylomicronemia, and conditions of triglyceride-rich lipoprotein (TRL) remnant excess due to its inhibition of lipoprotein lipase (LPL) and hepatic lipase, leading to decreased hepatic reuptake of TRLs, as well as enhanced synthesis and secretion of VLDL from the liver. ApoCIII gain-of-function mutations are associated with atherosclerosis and coronary heart disease (CHD), and contribute to the development of cardiometabolic syndrome, hypertriglyceridemia, and type 2 diabetes mellitus. Conversely, loss-of-function mutations in ApoCIII are associated with lower levels of plasma triglycerides (TG), attenuation of vascular inflammatory processes such as monocyte adhesion and endothelial dysfunction, and potentially, a reduction in the incidence and progression of atherosclerosis and cardioprotection.

RECENT FINDINGS

Evidence is now emerging that volanesorsen, a second-generation antisense oligonucleotide drug targeting ApoCIII messenger RNA resulting in decreases in TG in patients with familial chylomicronemia syndrome, severe hypertriglyceridemia, and metabolic dyslipidemia with type 2 diabetes giving support to the hypothesis that ApoCIII is a powerful inhibitor of LPL, and when reduced, endogenous clearance of TRLs can result in substantial reductions in TG levels. Discovery of the ApoCIII inhibitor volanesorsen opens a new era of lipid-lowering drugs for reduction in TG and potentially for reduction in LDL-C. Herein, this review will provide an update on the pathophysiology of ApoCIII-linked atherosclerosis and the development of the first drug to target ApoCIII, volanesorsen, as a promising lipid-lowering agent.

Pravastatin improves postprandial endothelial dysfunction and hemorheological deterioration in patients with effort angina pectoris

Postprandial hypertriglyceridemia and hyperglycemia may promote endothelial and hemorheological dysfunction. The present study investigated the effects of pravastatin on endothelial function and hemorheology in patients with stable angina pectoris (AP) before and after eating a test meal. We recruited 26 patients with stable AP who had impaired glucose tolerance and mild dyslipidemia and six healthy men as controls to assess endothelial function and hemorheological behavior. In each group, we measured forearm blood flow (FBF) during post-ischemic reactive hyperemia and obtained blood samples before and 2 h after the test meal. Pravastatin 20 mg/day was then commenced in the 26 AP patients. The above tests were repeated after 2 days and 6 months. Maximum FBF during hyperemia in the baseline fasting phase was significantly lower in the AP patients than in the controls (p < 0.05). Fasting and postprandial FBF during reactive hyperemia time-dependently improved after pravastatin treatment (p < 0.05 vs. baseline data for each phase). Pravastatin treatment for 6 months, but not for 2 days, inhibited leukocyte activation and improved hemorheological parameters. In conclusion, pravastatin treatment for 6 months improved fasting and postprandial endothelial and hemorheological dysfunction in AP patients.

Remnant lipoproteinemia predicts cardiovascular events in patients with type 2 diabetes and chronic kidney disease

BACKGROUND

Patients having type 2 diabetes mellitus (DM) and chronic kidney disease (CKD) are at high risk of cardiovascular events. Triglyceride-rich lipoprotein levels are synergistically increased in patients with DM and CKD. This study examined the predictive value of remnant lipoprotein levels for cardiovascular events in patients with DM and CKD.

METHODS

Three hundred and sixty-five patients with type 2 DM and CKD were enrolled. Serum levels of remnant lipoproteins (remnant-like lipoprotein particles cholesterol; RLP-C) were measured by an immunoseparation method. All patients were followed prospectively for a period of 45±23 months or until occurrence of one of the following events: cardiac death, non-fatal myocardial infarction, unstable angina requiring unplanned coronary revascularization, or ischemic stroke.

RESULTS

During the follow-up period, 59 patients had cardiovascular events. Multivariate Cox analysis revealed that high levels of RLP-C (≥4.3mg/dL; median value) were a significant risk factor for cardiovascular events, independent of traditional risk factors (HR: 1.30; 95% CI: 1.04-1.63; p=0.02). The addition of high levels of RLP-C to traditional risk factors improved net reclassification improvement (NRI) and integrated discrimination improvement (IDI) (NRI 0.36, p=0.01; and IDI 0.03, p=0.02).

CONCLUSIONS

RLP-C is useful for risk assessment of future cardiovascular events in patients having type 2 DM and CKD.

Postprandial hyperlipidemia as a potential residual risk factor

Statin therapy targeting reduction of low-density lipoprotein cholesterol (LDL-C) decreases the risk of coronary heart disease (CHD) and all-cause mortality. However, a substantial number of cases of CHD are not prevented and residual risk factors remain unsettled. A high triglyceride (TG) level is considered to be an important and residual risk factor. Postprandial hyperlipidemia is a condition in which TG-rich chylomicron remnants are increased during the postprandial period and hypertriglycedemia is protracted. Postprandial hyperlipidemia evokes atherogenesis during the postprandial period. Several prospective studies have revealed that nonfasting serum TG levels predict the incidence of CHD. Values of TG, remnant lipoprotein cholesterol, and remnant lipoprotein TG after fat loading were significantly higher in diabetes patients with insulin resistance than in diabetes patients without insulin resistance. Endothelial dysfunction is an initial process of atherogenesis and it contributes to the pathogenesis of CHD. Postprandial hyperlipidemia (postprandial hypertriglyceridemia) is involved in the production of proinflammatory cytokines, recruitment of neutrophils, and generation of oxidative stress, resulting in endothelial dysfunction in healthy subjects, hypertriglyceridemic patients, or type 2 diabetic patients. Effective treatment has not been established till date. Ezetimibe or omega-3 fatty acids significantly decrease postprandial TG elevation and postprandial endothelial dysfunction. Ezetimibe or omega-3 fatty acids added to statin therapy reduce serum TG levels and result in good outcomes in patients with CHD. In conclusion, postprandial hyperlipidemia is an important and residual risk factor especially in patients with insulin resistance syndrome (metabolic syndrome) and diabetes mellitus. Further studies are needed to establish effective treatment.

Effect of the Probiotic Saccharomyces boulardii on Cholesterol and Lipoprotein Particles in Hypercholesterolemic Adults: A Single-Arm, Open-Label Pilot Study

OBJECTIVES

Elevated blood cholesterol levels are a major risk factor for coronary artery disease, the leading cause of death worldwide. Probiotics have been investigated as potential cholesterol-lowering therapies, but no previous studies have assessed the effect of the probiotic yeast Saccharomyces boulardii on cholesterol levels in human volunteers. The objective of this study was to examine the effect of S. boulardii on serum cholesterol and lipoprotein particles in hypercholesterolemic adults.

DESIGN

This study was a single-arm, open-label pilot study.

SUBJECTS

Twelve hypercholesterolemic participants were recruited into the study; one dropped out.

INTERVENTION

Participants took 5.6×10(10) colony forming unit (CFU) encapsulated S. boulardii (Saccharomyces cerevisiae var. boulardii CNCM I-1079) twice daily for an 8-week period.

OUTCOME MEASURES

Fasting concentrations of cholesterol (total cholesterol, low-density lipoprotein-cholesterol [LDL-C], high-density lipoprotein-cholesterol [HDL-C], and triglycerides), lipoprotein particles (very-low-density lipoprotein-particle [VLDL-P], remnant lipoprotein particle [RLP-P], total LDL-P, LDL III-P, LDL IV-P, total HDL-P, and HDL 2b-P), and additional cardiovascular biomarkers (apo B-100, lipoprotein [a], high-sensitivity C-reactive protein, homocysteine, fibrinogen, and insulin) were measured at baseline, after 4 weeks, and after 8 weeks.

RESULTS

Remnant lipoprotein particles decreased by 15.5% (p=0.03) over the 8-week period. The remaining outcome measures were not significantly altered.

CONCLUSIONS

In this pilot study, 8 weeks of daily supplementation with S. boulardii lowered remnant lipoprotein, a predictive biomarker and potential therapeutic target in the treatment and prevention of coronary artery disease.

Utility of the Japan arteriosclerosis longitudinal study score for identifying a high risk for vasospastic angina

OBJECTIVE

The aim of this study was to investigate whether the Japan Arteriosclerosis Longitudinal Study (JALS) score, which is calculated from the traditional atherosclerotic coronary risk, is associated with the incidence of coronary vasospasms.

METHODS

We performed vasospasm provocation tests with acetylcholine in 109 patients referred to our hospital due to suspected vasospastic angina and subsequently calculated the atherosclerotic risk score according to the JALS score. Consequently, coronary vasospasms were evoked in 51 patients. The patients were divided into three groups according to the tertile of the JALS score: 1st, <28, n=36; 2nd, 28-41, n=36, 3rd, >42, n=37. The third tertile exhibited the greatest risk for vasospasms. A multivariate logistic regression analysis revealed that the JALS score (odds ratio: 1.686, p<0.05) was independently associated with the incidence of vasospasms.

CONCLUSION

The JALS score can serve as a useful tool for evaluating patients with suspected coronary vasospasms.

Dietary fat alters the expression of cortistatin and ghrelin systems in the PBMCs of elderly subjects: putative implications in the postprandial inflammatory response

SCOPE

Dietary fat influences systemic inflammatory status, which determines the progression of age-associated diseases. Since somatostatin (SST), cortistatin (CORT), and ghrelin systems modulate inflammatory response, we aim to comprehensively characterize the presence and regulation of the components of these systems in the peripheral blood mononuclear cells (PMBCs), a subset of white blood cells placed at the crossroad between diet and inflammation, in response to diets with different fat composition, and during the postprandial phase in elderly subjects.

METHODS AND RESULTS

The applied nutrigenomic, inflammation-related PBMC-based approach revealed that the majority of components of SST/CORT and ghrelin systems are present in the human PBMCs. Particularly, CORT, SST/CORT receptors (sst2, sst3, sst5, and sst5TMD4), ghrelin, its acylating enzyme (GOAT), In1-ghrelin variant, and GHSR1b were detected in PBMCs. Their expression was altered in the long-term by diet composition, and in the short-term, during the postprandial phase. Of particular relevance is the postprandial elevation of CORT, sst2, and sst5 expression in PBMCs of subjects under n-3 PUFAs-enriched diet.

CONCLUSION

Our results suggest a potential relevant role of CORT/ssts and ghrelin systems in regulating PBMCs response to nutrient intake, which could help to explain the positive effects of n-3 PUFAs-enriched diets in reducing the inflammatory response.

Association of lifestyle-related factors with circadian onset patterns of acute myocardial infarction: a prospective observational study in Japan

OBJECTIVE

The onset of acute myocardial infarction (AMI) shows characteristic circadian variations involving a definite morning peak and a less-defined night-time peak. However, the factors influencing the circadian patterns of AMI onset and their influence on morning and night-time peaks have not been fully elucidated.

DESIGN, SETTING AND PARTICIPANTS

An analysis of patients registered between 1998 and 2008 in the Osaka Acute Coronary Insufficiency Study, which is a prospective, multicentre observational study of patients with AMI in the Osaka region of Japan. The present study included 7755 consecutive patients with a known time of AMI onset.

MAIN OUTCOMES AND MEASURES

A mixture of two von Mises distributions was used to examine whether a circadian pattern of AMI had uniform, unimodal or bimodal distribution, and the likelihood ratio test was then used to select the best circadian pattern among them. The hierarchical likelihood ratio test was used to identify factors affecting the circadian patterns of AMI onset. The Kaplan-Meier method was used to estimate survival curves of 1-year mortality according to AMI onset time.

RESULTS

The overall population had a bimodal circadian pattern of AMI onset characterised by a high and sharp morning peak and a lower and less-defined night-time peak (bimodal p<0.001). Although several lifestyle-related factors had a statistically significant association with the circadian patterns of AMI onset, serum triglyceride levels had the most prominent association with the circadian patterns of AMI onset. Patients with triglyceride ≥150 mg/dL on admission had only one morning peak in the circadian pattern of AMI onset during weekdays, with no peaks detected on weekends, whereas all other subgroups had two peaks throughout the week.

CONCLUSIONS

The circadian pattern of AMI onset was characterised by bimodality. Notably, several lifestyle-related factors, particularly serum triglyceride levels, had a strong relation with the circadian pattern of AMI onset.

TRIAL REGISTRATION NUMBER

UMIN000004575.

How do elevated triglycerides and low HDL-cholesterol affect inflammation and atherothrombosis?

This review article summarizes recent research into the mechanisms as to how elevated levels of triglyceride (TG) and low levels of high- density- lipoprotein cholesterol (HDL-C) contribute to inflammation and atherosclerosis. Evidence supports the role of TG-rich lipoproteins in signaling mechanisms via apolipoproteins C-III and free fatty acids leading to activation of NFKβ, VCAM-1 and other inflammatory mediators which lead to fatty streak formation and advanced atherosclerosis. Moreover, the cholesterol content in TG-rich lipoproteins has been shown to predict CAD risk better than LDL-C. In addition to reverse cholesterol transport, HDL has many other cardioprotective effects which include regulating immune function. The "functionality" of HDL appears more important than the level of HDL-C. Insulin resistance and central obesity underlie the pathophysiology of elevated TG and low HDL-C in metabolic syndrome and type 2 diabetes. Lifestyle recommendations including exercise and weight loss remain first line therapy in ameliorating insulin resistance and the adverse signaling processes from elevated levels of TG-rich lipoproteins and low HDL-C.

Abnormal Lipid levels as a risk factor of eclampsia, study conducted in tertiary care Hospitals of Khyber Pakhtunkhwa Province - Pakistan

Objective: To evaluate abnormal lipid metabolism as a risk factor of eclampsia in pregnant women.

Methods: This cross sectional study was conducted in three tertiary care hospitals of Peshawar. Serum total cholesterol (TC), high density lipoprotein cholesterol (HDL-C), low density lipoprotein cholesterol (LDL-C), very low density lipoprotein cholesterol (VLDL-C), triglyceride (TG), apolipoprotein A1 (APO-A1), APO-B100, lipoprotein-a (Lpa) were measured in 110 women with eclampsia and compared with 90 healthy pregnant women. Mean lipid levels in cases and controls were compared using student’s t test”.

Results: Mean systolic/diastolic blood pressure, TC, TG, VLDL-C and Lpa levels were significantly higher (p<0.001) in patients compared to control women. Similarly TC: HDL-C, LDL-C: HDL-C and TG: HDL-C ratio in the patients group were significantly higher (p<0.001) and HDL-C: VLDL-C ratio was significantly lower (p<0.001) in the patients as compared to control group. Undesirable cholesterol were noted in 35.8% patients, HDL-C in 50.5%, borderline high concentration of LDL-C in 23.6%, high triglycerides levels in 73.2%, undesirable cholesterol ratio in 52.3% and undesirable LDL-C ratio were noted in 82.1% patients of eclampsia.

Conclusion: Serum lipids were found significantly higher thus early assessment may be helpful in prevention of complications in the eclampsia patients.

Age-related trends of blood pressure levels by apolipoprotein E genotype: the Bambuì Cohort Study of Ageing (1997-2008)

The role of apolipoprotein E (apoE) polymorphisms in regulating blood pressure (BP) is still not clear. The aim of this study was to examine longitudinal changes in BP levels by apoE genotypes in a population-based prospective cohort of elderly subjects, and explore interactions with plasma lipids and uric acid. Subjects whose apoE genes had been genotyped at baseline (1408, representing 80.8% of all the elderly residents in Bambuì city, south-eastern Brazil; age range 60-95 years) were included in the analysis. Repeated BP measurements were obtained in four waves. Multi-level random-effects pattern-mixture models were used to evaluate the age-related BP trajectories, accounting for non-ignorable dropouts/deaths and handling heterogeneities as random parameter variations. Subjects with the ɛ4/4 genotype and high levels of low-density lipoprotein cholesterol had higher systolic BP levels at 60 years of age than those with the other genotypes (154.5 vs. 133.2 mm Hg, P=0.020), but this was not the case among the older subjects. Systolic BP increased more rapidly with age in the ɛ2 carriers, leading to significantly higher levels among the oldest. This relationship seemed to be modulated by uric acid levels, as it was present in the subjects with the ɛ2/3 genotype and high uric acid levels, and in those with the ɛ2/4 genotype and low or normal uric acid levels. The differences in systolic BP between the genotypes were age dependent, and the shift between the ɛ4 and ɛ2 alleles suggest that these alleles are involved in the different mechanisms leading to increased BP in middle-aged and elderly subjects.

Ezetimibe inhibits lymphatic transport of esterified cholesterol but not free cholesterol in thoracic lymph duct-cannulated rats

PURPOSE

Ezetimibe has been shown to inhibit dietary cholesterol absorption in animal models and humans, but studies on lymphatic lipid transport have not yet been performed. Rats subjected to permanent lymph duct cannulation were used to investigate the effects of ezetimibe on lipid transport.

METHODS

Rats were fed diets with and without ezetimibe (5.0 mg/kg), and their lymph was collected after feeding to quantify lymphatic lipid levels. Total cholesterol content in the intestinal mucosa was also measured.

RESULTS

Rats that consumed ezetimibe had significantly lower lymphatic total cholesterol transport with the reduction of esterified cholesterol transport. According to the calculation based on cholesterol consumption, ezetimibe reduced the total cholesterol lymphatic recovery rate by 54 %. We also determined that ezetimibe significantly reduced the total cholesterol content in the intestinal mucosa.

CONCLUSION

This is the first direct evidence that ezetimibe inhibits esterified but not free cholesterol lymphatic transport in thoracic duct-cannulated rats. The results also indicate that ezetimibe is not involved in the lymphatic transport of triacylglycerols, phospholipids, or α-tocopherol.

A comparison of the efficacy of combined ezetimibe and statin therapy with doubling of statin dose in patients with remnant lipoproteinemia on previous statin therapy

BACKGROUND AND PURPOSE

It remains undetermined whether the addition of ezetimibe to ongoing statin therapy is more effective than increasing the dose of statin for reducing remnant lipoprotein levels in patients with remnant lipoproteinemia on previous statin treatment. This study examined whether combined ezetimibe and statin therapy resulted in a greater improvement in remnant lipoprotein levels and endothelial function than with the dose of statin in patients with remnant lipoproteinemia on previous statin treatment.

METHODS AND RESULTS

A total of 63 patients with stable coronary artery disease and high levels of remnant-like lipoprotein particle cholesterol (RLP-C) (≥5.0 mg/dL) on statin treatment were assigned randomly to two groups and treated with either addition of ezetimibe (10mg/day, n=32) or doubling of statin dose (n=31). The lipid profiles and flow-mediated dilation (FMD) of the brachial artery were measured at enrollment and after 6 months of treatment. Statin and ezetimibe combined therapy reduced RLP-C and improved FMD to a greater extent than doubling the statin dose (% reduction in RLP-C, 48 ± 18% vs. 33 ± 24%, respectively, p=0.01; % improvement in FMD, 47 ± 48% vs. 24 ± 23%, respectively, p=0.02).

CONCLUSIONS

The addition of ezetimibe to ongoing statin treatment reduced RLP-C levels and improved endothelial dysfunction to a greater extent than doubling the statin dose in patients with high RLP-C levels on previous statin treatment. The present results are preliminary and should be confirmed by further studies on a larger number of study patients.

High levels of remnant lipoprotein cholesterol is a risk factor for large artery atherosclerotic stroke

BACKGROUND AND PURPOSE

Remnant lipoproteins (RLPs) are products of partially catabolized chylomicrons and very-low-density lipoprotein, from which some triglycerides have been removed. These particles are smaller and denser than the parent particles and are believed to be strongly atherogenic. We explored the association between RLP cholesterol (RLP-C) and ischemic stroke, including stroke subtypes.

METHODS

A cohort of 142 ischemic stroke patients (90 men and 52 women; age, 65.2±12.8 years, mean±SD) was enrolled; all had acute infarcts confirmed by diffusion-weighted MRI, and had fasting lipograms. A full stroke-related evaluation was conducted on each patient. An outpatient population of 88 subjects without a history of cerebrovascular or cardiovascular disease served as a control group. Serum RLP fractions were isolated using an immunoaffinity gel containing specific antiapolipoprotein (anti-apo)B-100 and anti-apoA-I antibodies. RLP-C values were considered to be high when they were in the highest quartile of all values in the study.

RESULTS

High RLP-C values were more common in stroke patients than in control patients (31.0% vs. 14.8%, p=0.01), when 5.6 mg/dL (>75th percentile) was used as the cutoff value. Multivariable analyses indicated that RLP-C was a risk factor for stroke, with an odds ratio of 2.54 (p=0.045). The RLP-C level was higher in the large artery atherosclerosis subgroup (5.7±3.9 mg/dL) than in any other stroke subgroup (small vessel occlusion, 4.9±5.9 mg/dL; cardioembolism, 1.8±2.3 mg/dL; stroke of undetermined etiology, 3.1±2.9 mg/dL).

CONCLUSIONS

We have found an association between high RLP-C levels and ischemic stroke, and in particular large artery atherosclerotic stroke.

Comparative reactivity of remnant-like lipoprotein particles (RLP) and low-density lipoprotein (LDL) to LDL receptor and VLDL receptor: effect of a high-dose statin on VLDL receptor expression

BACKGROUND

Comparison of the reactivity of remnant-like lipoprotein particles (RLP) and LDL particles to LDL receptor and VLDL receptor has not been investigated.

METHODS

LDL receptor- or VLDL receptor-transfected ldlA-7, HepG2 and L6 cells were used. Human LDL and rabbit β-VLDL were isolated by ultracentrifugation. Human RLP was isolated using an immunoaffinity mixed gel. The effect of statin on lipoprotein receptors was examined.

RESULTS

Both LDL receptor and VLDL receptor recognized RLP. In LDL receptor transfectants, RLP, β-VLDL and LDL all bound to LDL receptor. Cold RLP competed efficiently with DiI-β-VLDL; however, cold LDL competed weakly. In VLDL receptor transfectants, RLP and β-VLDL bound to VLDL receptor, but not LDL. RLP bound to VLDL receptor with higher affinity than β-VLDL because of higher apolipoprotein E in RLP. LDL receptor expression was induced in HepG2 by the low concentration of statin while VLDL receptor expression was induced in L6 myoblasts at higher concentration.

CONCLUSIONS

RLP are bound to hepatic LDL receptor more efficiently than LDL, which may explain the mechanism by which statins prevent cardiovascular risk by primarily reducing plasma RLP rather than by reducing LDL. Additionally, a high-dose of statins also may reduce plasma RLP through muscular VLDL receptor.

Postprandial lipoprotein metabolism: VLDL vs chylomicrons

Since Zilversmit first proposed postprandial lipemia as the most common risk of cardiovascular disease, chylomicrons (CM) and CM remnants have been thought to be the major lipoproteins which are increased in the postprandial hyperlipidemia. However, it has been shown over the last two decades that the major increase in the postprandial lipoproteins after food intake occurs in the very low density lipoprotein (VLDL) remnants (apoB-100 particles), not CM or CM remnants (apoB-48 particles). This finding was obtained using the following three analytical methods; isolation of remnant-like lipoprotein particles (RLP) with specific antibodies, separation and detection of lipoprotein subclasses by gel permeation HPLC and determination of apoB-48 in fractionated lipoproteins by a specific ELISA. The amount of the apoB-48 particles in the postprandial RLP is significantly less than the apoB-100 particles, and the particle sizes of apoB-48 and apoB-100 in RLP are very similar when analyzed by HPLC. Moreover, CM or CM remnants having a large amount of TG were not found in the postprandial RLP. Therefore, the major portion of the TG which is increased in the postprandial state is composed of VLDL remnants, which have been recognized as a significant risk for cardiovascular disease.

Predictive value of remnant lipoprotein for cardiovascular events in patients with coronary artery disease after achievement of LDL-cholesterol goals

OBJECTIVES

Triglycerides-rich lipoproteins are related to residual cardiovascular risk in patients on lipid-lowering treatment who achieve low-density lipoprotein cholesterol (LDL-C) goals. This study examined the predictive value of remnant lipoprotein levels for cardiovascular events in patients with coronary artery disease (CAD) with LDL-C levels <100mg/dL on lipid-lowering therapy.

METHODS

Serum levels of remnant lipoproteins (remnant-like lipoprotein particles cholesterol; RLP-C) were measured by an immunoseparation method in 560 patients with CAD who had LDL-C levels <100mg/dL on lipid-lowering therapy, including statin (58%), fibrate (13%) or diet only (29%). All the patients were followed prospectively for a period of ≤ 36 months or until occurrence of one of the following events: cardiac death, non fatal myocardial infarction, unstable angina requiring coronary revascularization, or ischemic stroke.

RESULTS

During a mean follow-up period of 33 months, 40 events occurred. Stepwise multivariate Cox proportional hazard analysis showed that RLP-C was a significant predictor of cardiovascular events after adjustment for known risk factors and lipid variables including triglycerides, non-high-density lipoprotein (HDL)-C, and total apolipoprotein B (HR 1.53, 95% CI 1.35-1.97, p<0.01). The c-statistics showed that addition of RLP-C had a greater incremental effect on the predictive value of conventional risk factors than addition of non-HDL-C or total apolipoprotein B.

CONCLUSIONS

RLP-C was superior to non-HDL-C for predicting cardiovascular events in CAD patients with LDL-C levels <100mg/dL on lipid-lowering treatment. Remnant lipoprotein may therefore be an important target for residual risk reduction after LDL-C goals on lipid lowering therapy.

Identification of diacylglycerol acyltransferase inhibitors from Rosa centifolia petals

Diacylglycerol acyltransferase (DGAT) catalyzes the final step of triacylglycerol (TAG) synthesis, and is considered as a potential target to control hypertriglyceridemia or other metabolic disorders. In this study, we found that the extract of rose petals suppressed TAG synthesis in cultured cells, and that the extract showed DGAT inhibitory action in a dose-dependent manner. Fractionation of the rose extract revealed that the DGAT inhibitory substances in the extract were ellagitannins; among them rugosin B, and D, and eusupinin A inhibited DGAT activity by 96, 82, and 84% respectively, at 10 μM. These substances did not inhibit the activities of other hepatic microsomal enzymes, glucose-6-phosphatase and HMG-CoA reductase, or pancreatic lipase, suggesting that ellagitannins inhibit DGAT preferentially. In an oral fat load test using mice, postprandial plasma TAG increase was suppressed by rose extract; TAG levels 2 h after the fat load were significantly lower in mice administered a fat emulsion containing rose extract than in control mice (446.3 ± 33.1 vs 345.3 ± 25.0 mg/dL, control vs rose extract group; P < 0.05). These results suggest that rose ellagitannins or rose extract could be beneficial in controlling lipid metabolism and used to improve metabolic disorders.

Dyslipidaemia in rheumatological autoimmune diseases

Autoimmunity forms the basis of many rheumatological diseases, and may contribute not only to the classical clinical manifestations but also to the complications. Many of the autoimmune rheumatological diseases, including rheumatoid arthritis and systemic lupus erythematosus are associated with an excess cardiovascular morbidity and mortality. Much of this excess cardiovascular risk can be attributed to atherosclerotic disease. Atherosclerosis is a complex pathological process, with dyslipidaemia and inflammation fundamental to all stages of plaque evolution. The heightened inflammatory state seen in conjunction with many rheumatological diseases may accelerate plaque formation, both through direct effects on the arterial wall and indirectly through inflammation-mediated alterations in the lipid profile. Alongside these factors, antibodies produced as part of the autoimmune nature of these conditions may lead to alterations in the lipid profile and promote atherosclerosis. In this review, we discuss the association between several of the rheumatological autoimmune diseases and dyslipidaemia, and the potential cardiovascular impact this may confer.

Identification of ACOX2 as a shared genetic risk factor for preeclampsia and cardiovascular disease

Preeclampsia (PE) is a serious complication of pregnancy, which is highly correlated with later life cardiovascular disease (CVD). Many risk factors are common for both diseases, but the contribution of shared genes remains to be determined. In this study, we used an integrative strategy to assess lipid traits as risk factors for PE and CVD by whole genome transcriptional profiling performed on Norwegian decidua basalis tissues (N = 95) from preeclamptic and normal pregnancies and on blood lymphocytes (N = 1240) from the San Antonio Family Heart Study (SAFHS). Among 222 genes that were differentially expressed (false discovery rate (FDR) P-value <0.05) between the PE, cases and controls, we found one gene, ACOX2 (acyl-coenzyme A oxidase 2, branched chain), that was downregulated in PE whose transcription was also inversely correlated with triglyceride levels (P = 5.6 × 10(-7); FDR P-value = 0.0002) in SAFHS. We further report associations between SNPs in the ACOX2 gene and the transcription level (P-value = 0.0045) of the gene, as well as with triglyceride levels (P-value = 0.0051). ACOX2 is involved in bile acid production, a process that has been associated with both oxidative stress and regulation of triglyceride levels. Oxidative stress and increased triglyceride levels are known risk factors for CVD and both have also been associated with PE. Our results suggest that downregulation of ACOX2 is a shared risk factor for PE and CVD.

Pokkuri Death Syndrome; sudden cardiac death cases without coronary atherosclerosis in South Asian young males

Sudden death is one of the major concerns in forensic medicine. Especially when the deceased is a young subject without significant history, the case will be of major interest to the authorities. Sudden unexplained cardiac death has been known as "Pokkuri Death Syndrome" (PDS) in Japan, "Lai Tai" in Thailand, "Bangungut" in the Philippines, "Dream Disease" in Hawaii, and "Sudden Unexpected Nocturnal Death Syndrome" among South Asian immigrants in the USA. However, the clinical and pathological features of these sudden death cases, especially the characteristics of no coronary atherosclerosis, are surprisingly similar and mainly occur among Southeast Asian young males during sleep in the midnight. In this manuscript, we have reviewed the pathological characteristics and the possible mechanism of death in PDS cases, which were associated with significantly elevated remnant lipoproteins in plasma as revealed from our studies during the past 15 years in Japan. Although elevated plasma remnant lipoproteins have been known to be strongly atherogenic, coronary atherosclerosis was not observed in PDS cases. PDS cases were shown to be an interesting cardiovascular disease death discovered in forensic medicine research, which may suggest the difference between the occurrence of cardiovascular events and the severity of coronary atherosclerosis as separate factors. These observations in PDS cases suggest the possibility that the intervention could be more targeted to suppress the cardiovascular events rather than to slow down the progression of atherosclerosis, which is now most extensively targeted for the therapy of cardiovascular disease in Western countries.

Comparative study of bezafibrate and pravastatin in patients with coronary artery disease and high levels of remnant lipoprotein

BACKGROUND

Remnant lipoproteinemia is a strong risk factor for cardiovascular (CV) diseases. This study examined which of 2 common lipid-lowering drugs (fibrates and statins) is more effective in patients with remnant lipoproteinemia and if lowering remnant lipoprotein levels can reduce CV risk.

METHODS AND RESULTS

Remnant lipoprotein levels were measured by an immunoseparation method (remnant-like lipoprotein particles cholesterol: RLP-C) in 274 patients with coronary artery disease and high RLP-C levels (>or=5.0 mg/dl). They were randomly assigned to receive bezafibrate (200-400 mg/day) or pravastatin (10-20 mg/day), and were prospectively followed-up for 1 year or until the occurrence of CV events. Complete follow-up data were obtained in 180 patients. RLP-C levels at 1 year of treatment were reduced more by bezafibrate than pravastatin (37% and 25% from baseline, respectively). During follow-up, bezafibrate-treated patients had 3 CV events, compared with 12 events in pravastatin-treated patients (P<0.01). In multivariate logistic regression analysis, a decrease in RLP-C level was significantly associated with a reduction in CV events after adjustment for treatment group and changes in levels of other lipids.

CONCLUSIONS

Bezafibrate therapy decreased RLP-C levels to a greater extent than pravastatin and a decrease in RLP-C level may be associated with a reduction in CV events in patients with high RLP-C levels.

Remnant lipoproteins as strong key particles to atherogenesis

Recent epidemiologic studies have revealed that hypertriglyceridemia is associated with atherosclerosis independent of other coronary risk factors. However, it is difficult to select patients at high risk for coronary artery disease using only serum triglyceride levels compared with low-density lipoprotein cholesterol levels since multiple factors are associated with elevating triglycerides. Atherosclerotic diseases with high triglyceride levels can be found in patients with familial combined hyperlipidemia, diabetes mellitus, and metabolic syndrome, in which remnant lipoproteins accumulate in the circulating blood. Recent researches have paid attention to remnant lipoproteins as atherogenic particles with the development of methods for measuring remnant cholesterol levels and apolipoprotein B-48 levels directly from human serum. Measurement of these parameters in addition to serum triglycerides may help to distinguish high-risk patients and enable us to prevent or suppress the progression of atherosclerotic diseases in those patients. However, questions remain to be answered to evaluate the significance of remnant lipoproteins. Here, we focus on three issues: the underlying problems in measuring remnant lipoprotein cholesterol, the assessment of postprandial hyperlipidemia as an atherogenic condition, and finally a review of our experimental and clinical findings about the mechanisms by which remnant lipoproteins induce atherosclerosis.

Dietary saturated and unsaturated fats as determinants of blood pressure and vascular function

The amount and type of dietary fat have long been associated with the risk of CVD. Arterial stiffness and endothelial dysfunction are important risk factors in the aetiology of CHD. A range of methods exists to assess vascular function that may be used in nutritional science, including clinic and ambulatory blood pressure monitoring, pulse wave analysis, pulse wave velocity, flow-mediated dilatation and venous occlusion plethysmography. The present review focuses on the quantity and type of dietary fat and effects on blood pressure, arterial compliance and endothelial function. Concerning fat quantity, the amount of dietary fat consumed habitually appears to have little influence on vascular function independent of fatty acid composition, although single high-fat meals postprandially impair endothelial function compared with low-fat meals. The mechanism is related to increased circulating lipoproteins and NEFA which may induce pro-inflammatory pathways and increase oxidative stress. Regarding the type of fat, cross-sectional data suggest that saturated fat adversely affects vascular function whereas polyunsaturated fat (mainly linoleic acid (18 : 2n-6) and n-3 PUFA) are beneficial. EPA (20 : 5n-3) and DHA (22 : 6n-3) can reduce blood pressure, improve arterial compliance in type 2 diabetics and dyslipidaemics, and augment endothelium-dependent vasodilation. The mechanisms for this vascular protection, and the nature of the separate physiological effects induced by EPA and DHA, are priorities for future research. Since good-quality observational or interventional data on dietary fatty acid composition and vascular function are scarce, no further recommendations can be suggested in addition to current guidelines at the present time.

Brachial artery ultrasound: a noninvasive tool in the assessment of triglyceride-rich lipoproteins

In recent years, endothelial dysfunction has been identified as an early feature of atherosclerosis. Endothelial function can be measured noninvasively by using brachial artery ultrasound. A variety of factors associated with atherosclerosis also impair endothelial function. Some of these factors are lipoproteins such as various forms of low-density lipoproteins, postprandial chylomicron remnants, fasting triglyceride-rich particles, and free fatty acids. A high-fat diet also has an adverse effect on endothelial function. Several interventions can improve endothelial function and, at the same time, reduce cardiovascular events. Measuring endothelial function may eventually serve as a useful index to determine an individual's risk for coronary artery disease.

The effects of low-dose simvastatin and ezetimibe compared to high-dose simvastatin alone on post-fat load endothelial function in patients with metabolic syndrome: a randomized double-blind crossover trial

BACKGROUND AND AIMS

Insulin resistance is associated with postprandial hyperlipidemia and endothelial dysfunction. Patients with metabolic syndrome, characterized by insulin resistance, are at increased cardiovascular risk. The aim of the present study was to investigate whether a similar low-density lipoprotein cholesterol (LDL-c) reduction with combination therapy of low-dose simvastatin and ezetimibe or with high-dose simvastatin alone has similar effects on (post-fat load) endothelial function.

METHODS

Randomized, double blind, crossover trial in 19 male obese patients with metabolic syndrome with high-dose simvastatin 80 mg versus combination therapy of low-dose simvastatin 10 mg with ezetimibe 10 mg. Fasting and post-fat load lipids and endothelial function (brachial artery flow-mediated dilation) were determined.

RESULTS

Fasting LDL-c concentrations (2.1 +/- 0.5 mmol/L) and fasting endothelial function (6.9 +/- 0.8 vs. 7.6 +/- 1.2%) were the same after both treatments. Although post-fat load plasma triglycerides concentrations were higher (3.2 +/- 0.4 vs. 2.6 +/- 0.2 mmol x h/L) with combination therapy compared to monotherapy, ApoB particles were comparable (0.9 +/- 3.3 vs. -0.2 +/- 2.3 g x h/L). Combination therapy did not decrease post-fat load endothelial function (7.6 +/- 1.2 vs. 7.7 +/- 1.6%), contrary to high-dose simvastatin monotherapy (6.9 +/- 0.8 vs. 4.3 +/- 0.6%).

CONCLUSIONS

Combination therapy with low-dose simvastatin and ezetimibe preserved post-fat load endothelial function, contrary to treatment with high-dose simvastatin monotherapy in male metabolic syndrome patients. There were no differences in fasting lipid profiles and endothelial function.