Clinical relevance of the biochemical, metabolic, and genetic factors that influence low-density lipoprotein heterogeneity

Association of LDL-cholesterol subfractions with cardiovascular disorders: a systematic review

BACKGROUND

Cardiovascular disorders (CVDs) are the leading cause of death worldwide. This study aimed to evaluate the association between low-density lipoprotein (LDL) subfractions and cardiovascular disorders.

METHODS

To ensure the rigor of the systematic review, the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines were used. For this systematic review, a comprehensive search strategy was performed in important databases including PubMed, Scopus, Embase, International Statistical Institute (ISI) Web of Science, and google scholar from 2009 to February 2021. The following terms were used for systematic search: low-density lipoprotein, LDL, subfractions, subclasses, nuclear magnetic resonance, NMR, chromatography, high-pressure liquid, HPLC, cardiovascular disease, cerebrovascular, and peripheral vascular disease. Also, for evaluating the risk of bias, the Newcastle-Ottawa scale was employed.

RESULTS

At the end of the search process, 33 articles were included in this study. The results of most of the evaluated studies revealed that a higher LDL particle number was consistently associated with increased risk for cardiovascular disease, independent of other lipid measurements. Also, small dense LDL was associated with an increased risk of CVDs. There was no association between LDL subfraction and CVDs in a small number of studies.

CONCLUSIONS

Overall, it seems that the evaluation of LDL subclasses can be used as a very suitable biomarker for the assessment and diagnosis of cardiovascular diseases. However, further studies are required to identify the mechanisms involved.

The LDL-C/ApoB ratio predicts cardiovascular and all-cause mortality in the general population

BACKGROUND

Generally, low-density lipoprotein (LDL) particle size can be inferred from the LDL cholesterol concentration to total apolipoprotein B concentration ratio (LDL-C/ApoB ratio, hereinafter called LAR), which is a good predictor of cardiovascular disease. However, the predictive ability of LAR for mortality risk in the general population is still unclear. This study aimed to explore the association between LAR and cardiovascular as well as all-cause mortality among American adults.

METHODS

The present study was a secondary analysis of existing data from the National Health and Nutrition Examination Survey (NHANES). The final analysis included 12,440 participants from 2005 to 2014. Survival differences between groups were visualized using Kaplan‒Meier curves and the log-rank test. The association of LAR with cardiovascular and all-cause mortality was evaluated using multivariate Cox regression and restricted cubic spline analysis. Age, sex, coronary artery disease, diabetes, lipid-lowering medication use and hypertriglyceridemia were analyzed in subgroup analyses.

RESULTS

The median age in the study cohort was 46.0 years [interquartile range (IQR): 31.0-62.0], and 6,034 (48.5%) participants were male. During the follow-up period, there were 872 (7.0%) all-cause deaths and 150 (1.2%) cardiovascular deaths. Compared with individuals without cardiovascular events, those who experienced cardiovascular deaths had a lower LAR (1.13 vs. 1.25) (P < 0.001). The adjusted Cox regression model indicated that lower LAR was an independent risk factor for both cardiovascular [hazard ratio (HR) = 0.304, 95% confidence interval (CI): 0.114-0.812] and all-cause mortality (HR = 0.408, 95% CI: 0.270-0.617). Moreover, a significant age interaction was observed (P for interaction < 0.05), and there was a strong association between LAR and mortality among participants over 65 years of age. Further analysis showed an inverse association between LAR and both cardiovascular and all-cause mortality.

CONCLUSIONS

LAR can independently predict cardiovascular and all-cause mortality in the general population.

Obesity and diabetes

Obesity, which has currently reached pandemic dimensions, is usually accompanied by diabetes mellitus type 2 (T2DM). These two conditions share common pathophysiological mechanisms. Adipose tissue secretes cytokines which are involved in inflammation and various endocrine functions. As for T2DM, it is characterized also by inflammation, mitochondrial dysfunction, and hyperinsulinemia. These conditions occur also in other diseases related to obesity and T2DM, like cardiovascular disease (CVD) and nonalcoholic fatty liver disease (NAFLD). Thus, management of obesity-related complications with lifestyle modification, anti-obesity drugs, and bariatric surgery, all contribute to improvement in any of these conditions. This review provides an overview of the literature addressing the association between obesity and T2DM, briefly discussing the pathophysiological mechanisms linking these conditions and outlining the management approach at the overlap of obesity and T2DM.

Certain sulfonylurea drugs increase serum free fatty acid in diabetic patients: A systematic review and meta-analysis

BACKGROUND

Sulfonylurea (SU) is a commonly used antidiabetic drugs effective for type 2 diabetes mellitus. Previous studies have reported that the SU treatment could alter the serum free fatty acid (FFA) concentration in diabetic patients; however, their exact effects remain unknown.

AIM

To assess the impact of SU on the FFA level in diabetic patients.

METHODS

A systematic literature search was conducted by consulting the PubMed, EMBASE, Cochrane Library, Reference Citation Analysis (https://www.referencecitationanalysis.com/), and Web of Science databases from January 1, 1991 to July 30, 2021. Either a fixed-effects model or random-effects model was applied to study the association between SU treatment and FFA concentration according to the heterogeneity test. Two investigators independently performed data extraction. The mean difference (MD) and corresponding 95% confidence interval (CI) were used to measure effect size. R3.5.1 software was utilized for conducting statistical analyses.

RESULTS

A total of 13 studies with 2273 individuals were selected. Results indicated that FFA concentration increased slightly after treatment with SU (MD = 0.08, 95%CI: 0.03-0.12, P < 0.01). In addition, we found that SU treatment combined with other antidiabetics could also increase the concentration of serum FFA (MD = 0.14, 95%CI: 0.01-0.28, P < 0.01). Regarding the type of SU, there was no significant difference in FFA concentration with glimepiride or glibenclamide. FFA concentration was higher at ≥ 12 wk (MD = 0.09, 95%CI: 0.04-0.13) but not at < 12 wk (MD = 0.01, 95%CI: -0.07-0.09).

CONCLUSION

SU treatment could increase the serum FFA concentration in diabetic patients. The fundamental underlying mechanism still needs further investigation.

Utilization of Small Dense Low-Density Lipoprotein Cholesterol Testing in Korean Patients Visiting Local Clinics and Hospitals

Small dense low-density cholesterol (sdLDL) has been the focus of studies due to its potential as an independent risk factor for atherosclerotic cardiovascular diseases. We aimed to investigate the utilization of sdLDL testing by LDL particle size analysis and the prevalence of an sdLDL predominant phenotype in Korean adult patients by visiting local clinics and hospitals. Among 9222 Korean adults (4577 men and 4645 women) with a median age of 62.8 years (interquartile range, IQR 54.5 to 71.8 years) undergoing lipid profile testing using LDL particle size analysis, the prevalence of hypercholesterolemia (total cholesterol ≥ 240 mg/dL), hypo HDL cholesterolemia (<40 mg/dL), and hyper LDL cholesterolemia (≥160 mg/dL) was 7.8%, 12.9%, and 0.5%, respectively. The overall prevalence of the sdLDL predominant non-A phenotype of LDL was 46.8% of study subjects. Approximately 32.8% of the study subjects possessed lipid test results that did not exhibit increased risk except for sdLDL (only the sdLDL predominant non-A phenotype as a risk factor). In Korea, sdLDL testing was utilized in patients whose LDL cholesterol level was not increased. Future studies to clarify the clinical significance of this test in the Korean population are needed.

Baseline Insulin Resistance Is a Determinant of the Small, Dense Low-Density Lipoprotein Response to Diets Differing in Saturated Fat, Protein, and Carbohydrate Contents

Individual responses to diet vary but causes other than genetics are poorly understood. This study sought to determine whether baseline values of homeostasis model assessment (HOMA-IR) was related to changes in small, dense low-density lipoprotein (sdLDL, i.e., LDL4, d = 1.044-1.063 g/mL) amounts quantified by isopycnic density profiling, in mildly hypercholesterolemic subjects (n = 27) consuming one of three low saturated fatty acid (SFA) diets: Dietary Approaches to Stop Hypertension (DASH), Beef in an Optimal Lean Diet (BOLD) and BOLD plus extra protein (BOLD+) when compared to a higher-SFA healthy American diet (HAD). The diets were consumed in random order for 5 wk, with 1 wk between diets. BOLD+ reduced fractional abundance (%) LDL4 (p < 0.05) relative to HAD, DASH and BOLD, and reductions in % LDL4 correlated with reductions in triglycerides (p = 0.044), total cholesterol (p = 0.014), LDL cholesterol (p = 0.004) and apolipoprotein B (p < 0.001). Responses to the four diets were similar (~12% decrease in % LDL4, p = 0.890) in the lower (<2.73 median) HOMA-IR subgroup but differed across diet conditions in the higher HOMA-IR subgroup (p = 0.013), in which % LDL4 was reduced with BOLD+ (-11%), was unchanged in BOLD and increased with the HAD (8%) and DASH (6%) diets (p < 0.05 for BOLD+ vs. HAD). Individual responses to diet interventions are influenced by presence and degree of insulin resistance as measured by HOMA-IR.

Waist-to-height ratio, waist circumference, body mass index, waist divided by height0.5 and the risk of cardiometabolic multimorbidity: A national longitudinal cohort study

BACKGROUND AND AIMS

Cardiometabolic multimorbidity (CM) is an increasing public health burden. This study aimed to evaluate the association of waist-to-height ratio (WHtR), waist circumference (WC), waist divided by height^0.5 (WHT.5R) and body mass index (BMI) with the risk of CM.

METHODS AND RESULTS

We used data from the China Health and Retirement Longitudinal Study (CHARLS). A total of 10,521 participants aged 45 years and over were recruited, including 8807 individuals with 0 cardiometabolic diseases at baseline (stage I) and 1714 individuals with 1 cardiometabolic disease at baseline (stage II). CM was defined as self-reporting of two or more of the following conditions: stroke, diabetes and heart disease. Logistic regression was conducted to estimate the odds ratios (ORs) and 95% confidence intervals (CIs). The net reclassification index (NRI) and integrated discrimination improvement (IDI) were used to evaluate the incremental predictive value beyond conventional factors. In stage I, an increased risk of CM was observed among participants with WHtR ≥0.5 (OR: 1.76, 95% CI: 1.05-2.97), WC ≥ 90 cm (men) + WC ≥ 80 cm (women) (OR: 2.06, 95% CI: 1.29-3.27), WHT.5R ≥ 6.54 cm^0.5 (OR: 1.81, 95% CI: 1.16-2.83) or BMI ≥24 kg/m² (OR: 1.48, 95% CI: 0.98-2.24). Furthermore, the NRI and IDI of WHtR, WC and WHT.5R were all higher than those of BMI. In stage II, the adjusted ORs (95% CIs) of WHtR, WC, WHT.5R and BMI were 2.04 (1.24-3.35), 1.89 (1.29-2.77), 1.86 (1.24-2.78) and 1.47 (1.06-2.04), respectively. In addition, WC exhibited the highest NRI and IDI.

CONCLUSION

WHtR, WC, WHT.5R and BMI are independent predictors of CM in the middle-aged and older Chinese population. WHtR, WC and WHT.5R show better abilities in predicting CM than BMI.

The effects of fat consumption on low-density lipoprotein particle size in healthy individuals: a narrative review

Cardiovascular disease (CVD) is the number one contributor to death in the United States and worldwide. A risk factor for CVD is high serum low-density lipoprotein cholesterol (LDL-C) concentrations; however, LDL particles exist in a variety of sizes that may differentially affect the progression of CVD. The small, dense LDL particles, compared to the large, buoyant LDL subclass, are considered to be more atherogenic. It has been suggested that replacing saturated fatty acids with monounsaturated and polyunsaturated fatty acids decreases the risk for CVD. However, certain studies are not in agreement with this recommendation, as saturated fatty acid intake did not increase the risk for CVD, cardiovascular events, and/or mortality. Furthermore, consumption of saturated fat has been demonstrated to increase large, buoyant LDL particles, which may explain, in part, for the differing outcomes regarding fat consumption on CVD risk. Therefore, the objective was to review intervention trials that explored the effects of fat consumption on LDL particle size in healthy individuals. PubMed and Web of Science were utilized during the search process for journal articles. The results of this review provided evidence that fat consumption increases large, buoyant LDL and/or decreases small, dense LDL particles, and therefore, influences CVD risk.

The association between low-density lipoprotein cholesterol/high-density lipoprotein cholesterol ratio cholesterol ratio and thickened carotid intima-media thickness: A case-control study

BACKGROUND

It is indicated that Low-density lipoprotein cholesterol/high-density lipoprotein cholesterol ratio (LDL-C/HDL-C ratio) has greater predictive value for thickened carotid intima-media thickness (CIMT) comparing with classic lipid parameters. However, there have been few reports about their association in general Chinese population.

METHOD

We included a total of 1220 CIMT participants and 2440 matched controls, who had ultrasonography of carotid artery during 2009 and 2016. Univariate and multivariate logistic regression models were used to calculate odds ratios (ORs) and 95% confidence intervals (CIs) for thickened CIMT risk associated with LDL-C/HDL-C ratio.

RESULT

In the univariate logistic regression model, there was significant association between LDL-C/HDL-C ratio and thickened CIMT (Q4 vs. Q1, OR = 1.94, 95% CI: 1.60-2.36; p_trend < 0.05). After adjusting for potential covariates, LDL-C/HDL-C ratio remained significantly associated with thickened CIMT (Q4 vs. Q1, OR = 1.81, 95% CI: 1.41-2.34, p_trend < 0.001; ≥3.05 v.s. <3.05, OR = 1.66, 95% CI: 1.37-2.02). In subgroup analyses, the association between LDL-C/HDL-C ratio and thickened CIMT remained significant in the subgroups stratified by sex, impaired fasting glucose (IFG), hypertension, and fatty liver disease but only remained significant in the subgroups of ≥45 years (OR = 2.01, 95% CI: 1.46-2.76; P_trend<0.05), BMI ≥24 (kg/m²) (OR = 2.22; 95% CI = 1.63-3.03; Ptrend < 0.05) and BMI ≥25 (kg/m²) (OR = 2.50, 95% CI: 1.76-3.54; P_trend < 0.05), dyslipidemia (OR = 3.28, 95% CI: 1.83-5,85; P_trend < 0.001), and without periodontitis (OR = 2.08, 95% CI: 1.54-2.81 ; Ptrend < 0.05) comparing Q4 to Q1. Similar results were observed in the subgroup analyses for LDL-C/HDL-C ratio ≥3.05 v.s. <3.05 except for the age stratification.

CONCLUSION

High LDL-C/HDL-C ratio could significantly increase the risk of thickened CIMT independent of gender, IFG, hypertension, and fatty liver disease in general Chinese population.

The effect of aged garlic extract on the atherosclerotic process - a randomized double-blind placebo-controlled trial

Background

One of the most serious secondary manifestations of Cardiovascular Disease (CVD) is coronary atherosclerosis. This study aimed to evaluate whether aged garlic extract (AGE) can influence coronary artery calcification (CAC) and to predict the individual effect of AGE using a standard process for data mining (CRISP–DM).

Method

This was a single-center parallel randomized controlled study in a university hospital in Europe. Patients were randomized, in a double-blind manner, through a computer-generated randomization chart. Patients with a Framingham risk score ≥ 10 after CT scan (n = 104) were randomized to an intake of placebo or AGE (2400 mg daily) for 1 year.

Main outcome measures were changes in CAC score and secondary outcome measures changes in blood pressure, fasting blood glucose, blood lipids and inflammatory biomarkers.

Result

104 patients were randomized and 46 in the active group and 47 in the placebo group were analyzed. There was a significant (p < 0.05) change in CAC progression (OR: 2.95 [1.05–8.27]), blood glucose (OR: 3.1 [1.09–8.85]) and IL-6 (OR 2.56 [1.00–6.53]) in favor of the active group. There was also a significant (p = 0.027) decrease in systolic blood pressure in the AGE group, from a mean of 148 (SD: 19) mmHg at 0 months, to 140 (SD: 15) mmHg after 12 months. The AGE Algorithm, at a selected probability cut-off value of 0.5, the accuracy score for CAC progression was 80%, precision score of 79% and recall score 83%. The score for blood pressure was 74% (accuracy, precision and recall). There were no side-effects in either group.

Conclusions

AGE inhibits CAC progression, lowers IL–6, glucose levels and blood pressure in patients at increased risk of cardiovascular events in a European cohort. An algorithm was made and was used to predict with 80% precision which patient will have a significantly reduced CAC progression using AGE. The algorithm could also predict with a 74% precision which patient will have a significant blood pressure lowering effect pressure using AGE.

Trial registration

Clinical trials NCT03860350, retrospectively registered (1/32019).

Triglyceride to high-density lipoprotein cholesterol and low-density lipoprotein cholestrol to high-density lipoprotein cholesterol ratios are predictors of cardiovascular risk in Iranian adults: Evidence from a population-based cross-sectional study

BACKGROUND

The superiority of TG/HDL-C and LDL-C/HDL-C ratios in predicting CVD risk is a matter of debates. Thus, the objective of this study was to compare TG/HDL-C and LDL-C to HDL-C ratios in predicting the risk of CVD events.

METHODS

In a population-based cross-sectional study, 567 representative participants aged 40 years or older were entered in the study in Babol, North of Iran. The demographic data, anthropometric measures, and the cardio metabolic risk factors were measured. The individual risk of CVD events was assessed by ACC/AHA risk model. ROC analysis was applied to estimate the diagnostic accuracy and the optimal cut-off points of TG/HDL-C and LDL-C/HDL-C ratios.

RESULTS

The AUC of TG/HDL-C and LDL-C/HDL-C ratios were rather similar and both parameters significantly predicted CVD risk in men comparably, and TG/HDL-C at optimal cutoff point of 3.6 produced 75% sensitivity and 39% specificity. However,in women TG/HDL-C with AUC of 0.65( p=0.091) at optimal cutoff value of 3.4 produced a sensitivity of 82% and specificity of 51%. The LDL-C/HDL-C ratio had no discriminative ability in predicting CVD risk in women. The adjusted OR of TG/HDL-C at 2nd quartile was significant (OR=3.22, 95% CI:1.25-8.29) and a greater association was found with 3rd and 4rth quartiles.

CONCLUSION

Both TG/HDL-C and LDL-C/HDL-C ratios comparably predict CVD risk in men, whereas in women only TG/ HDL-C is a significant predictor but not LDL-C/HDL-C.

Cardiovascular Risk Reduction in High-Risk Pediatric Patients: A Scientific Statement From the American Heart Association

This scientific statement presents considerations for clinical management regarding the assessment and risk reduction of select pediatric populations at high risk for premature cardiovascular disease, including acquired arteriosclerosis or atherosclerosis. For each topic, the evidence for accelerated acquired coronary artery disease and stroke in childhood and adolescence and the evidence for benefit of interventions in youth will be reviewed. Children and adolescents may be at higher risk for cardiovascular disease because of significant atherosclerotic or arteriosclerotic risk factors, high-risk conditions that promote atherosclerosis, or coronary artery or other cardiac or vascular abnormalities that make the individual more vulnerable to the adverse effects of traditional cardiovascular risk factors. Existing scientific statements and guidelines will be referenced when applicable, and suggestions for risk identification and reduction specific to each setting will be described. This statement is directed toward pediatric cardiologists, primary care providers, and subspecialists who provide clinical care for these young patients. The focus will be on management and justification for management, minimizing information on pathophysiology and epidemiology.

Impact of phytosterol supplementation on plasma lipoprotein(a) and free fatty acid (FFA) concentrations: A systematic review and meta-analysis of randomized controlled trials

BACKGROUND AND AIM

Although some earlier studies have indicated the effect of phytosterol (PS) supplementation on serum lipoprotein(a) (Lp(a)) and free fatty acid (FFA) concentration, findings are still conflicting. We aimed to assess the impact of PS supplementation on serum Lp(a) and FFA concentration through a systematic review and meta-analysis of available RCTs.

METHODS AND RESULTS

We performed a systematic search of all available RCTs conducted up to 21 February 2019 in the following databases: PubMed, Scopus, and Cochrane. The choice of fixed- or random-effect model for analysis was determined according to the I² statistic. Effect sizes were expressed as weighted mean difference (WMD) and 95% confidence interval (CI). Pooling of 12 effect sizes from seven articles revealed a significant reduction of Lp(a) levels following PS supplementation (MD: -0.025 mg/dl, 95% CI: -0.045, -0.004, p = 0.017) without significant heterogeneity among the studies (I² = 0.0%, p = 0.599). Also, PS supplementation significantly lowered FFA (MD: -0.138 mg/dl, 95% CI: -0.195, -0.081, p = 0.000) without significant heterogeneity among the studies (I² = 0.0%, p = 0.911). The results for meta-regression and sensitivity analysis were not significant.

CONCLUSION

The meta-analysis suggests that oral PS supplementation could cause a significant reduction in serum Lp(a) and FFA.

Ratio of triglyceride to high-density lipoprotein cholesterol and risk of major cardiovascular events in kidney transplant recipients

BACKGROUND

Dyslipidemia is common in kidney transplant (KT) recipients. We analyzed the ratio of triglyceride to high-density lipoprotein cholesterol (TG/HDL-C) in KT recipients to identify risk factors for major cardiovascular events (MACE).

METHODS

We retrospectively included KT recipients with a lipid profile performed 1 year after transplantation. We classified patients according to the TG/HDL-C divided into quintiles. Subsequently, we analyzed the association between TG/HDL-C and MACE, defined as heart failure, coronary artery disease, and cerebrovascular disease confirmed by imaging studies.

RESULTS

A total of 1301 KT recipients were enrolled. The median follow-up duration was 7.4 years (interquartile range 4.4-11.1 years). During the follow-up period, 80 (6.2%) patients developed MACE, which included 38 of unstable anginas, 9 of MIs, 19 of heart failures, 18 of cerebral infarcts, and 4 of cerebral hemorrhages. The fourth and fifth quintiles of TG/HDL-C showed a significantly increased risk of MACE [fourth quintile: adjusted hazard ratio (aHR), 3.38; 95% confidence interval (CI) 1.44-7.95; p = 0.005, fifth quintile: aHR, 2.67; 95% CI 1.13-6.30; p = 0.02]) compared to the second quintile of TG/HDL-C. This association is particularly evident in subgroups of non-DM, HTN, no history of CVD, and statin users.

CONCLUSIONS

Higher TG/HDL-C levels may be associated with MACE risk in KT recipients.

Two-Hour Postprandial Lipoprotein Particle Concentration Differs Between Lean and Obese Individuals

The concentrations of lipoprotein particles [high-density lipoproteins (HDLs), low-density lipoproteins (LDLs), very-low-density lipoproteins (VLDLs), and chylomicrons] are associated with the risk of cardiovascular diseases. Most studies have examined these associations in the fasting state. Previous studies have shown lipoprotein particle concentration change following meal, and these changes are different in individuals with obesity. In this study, we aimed to assess whether various meal compositions lead to adverse short-term (2-h) postprandial lipoproteinemia in obese insulin resistant (obese-IR) subjects as compared to lean insulin sensitive (lean-IS) subjects. In a randomized crossover trial, nine lean-IS and nine obese-IR Chinese men aged 22–35 years were challenged with isoenergetic and isovolumic meals rich in protein (HP), fat (HF), or carbohydrate (HC). Plasma samples were collected after a 10-h fast, as well as 1-h and 2-h post-meal and analyzed using nuclear magnetic resonance. Plasma concentration of large VLDLs and chylomicron particles was higher and increased more after all meals in obese-IR compared to lean-IS subjects. The HP meal decreased small LDL particle concentration in obese-IR subjects, and increased small HDL particle concentration in all subjects. The HF meal led to a decrease in small HDL concentration in all subjects. In conclusion, obese-IR subjects revealed a detrimental response to meal challenges even as early as 2-h after meal intake.

Metabolic disorders and inflammation are associated with familial combined hyperlipemia

BACKGROUND

Familial Combined Hyperlipidemia (FCH) is related to different metabolic disorders. The objective of this study was to evaluate the presence of alterations of hydrocarbonated metabolism and lipid profile together with inflammatory and adhesion molecules in subjects with FCH compared to controls.

METHODS

75 HFC patients and 75 healthy individuals were studied. Glucose, insulin, HOMA-IR index and lipid parameters, in addition to anti-oxidized LDL antibodies (Anti ox-LDL), small and dense LDL (sdLDL) and HDL subfractions, proinflammatory cytokines and adhesion molecules were measured.

RESULTS

FCH patients showed higher levels of hydrocarbonated metabolism parameters, total cholesterol, triglycerides, LDLc, Apolipoprotein B and non-HDLc (p < .001), and lower levels of HDLc (p < .001) and Apolipoprotein AI (p < .05) than controls. In addition, the inflammatory markers hsCRP, IL-6, IL-8, P-selectin, E-selectin and ICAM were all higher with (p < .05) respect to controls. The increase of sdLDL was correlated with the presence of IR and IL-6 levels. Significant differences in diameter and percentage of phenotype B LDL, small HDL subfractions and Anti ox-LDL were also detected between patients and controls.

CONCLUSIONS

The lipid characteristics of FCH are confirmed by IR and a low grade inflammatory state in patients, and are associated with the predominance of sdLDL and Anti ox-LDL.

Statin Effects on Metabolic Profiles: Data From the PREVEND IT (Prevention of Renal and Vascular End-stage Disease Intervention Trial)

BACKGROUND

Statins lower cholesterol by inhibiting HMG-CoA reductase, the rate-limiting enzyme of the metabolic pathway that produces cholesterol and other isoprenoids. Little is known about their effects on metabolite and lipoprotein subclass profiles. We, therefore, investigated the molecular changes associated with pravastatin treatment compared with placebo administration using a nuclear magnetic resonance-based metabolomics platform.

METHODS AND RESULTS

We performed metabolic profiling of 231 lipoprotein and metabolite measures in the PREVEND IT (Prevention of Renal and Vascular End-stage Disease Intervention Trial) study, a placebo-controlled randomized clinical trial designed to test the effects of pravastatin (40 mg once daily) on cardiovascular risk. Metabolic profiles were assessed at baseline and after 3 months of treatment. Pravastatin lowered low-density lipoprotein cholesterol (change in SD units [95% confidence interval]: -1.01 [-1.14, -0.88]), remnant cholesterol (change in SD units [95% confidence interval]: -1.03 [-1.17, -0.89]), and apolipoprotein B (change in SD units [95% confidence interval]: -0.98 [-1.11, -0.86]) with similar effect magnitudes. In addition, pravastatin globally lowered levels of lipoprotein subclasses, with the exception of high-density lipoprotein subclasses, which displayed a more heterogeneous response pattern. The lipid-lowering effect of pravastatin was accompanied by selective changes in lipid composition, particularly in the cholesterol content of very-low-density lipoproteinparticles. In addition, pravastatin reduced levels of several fatty acids but had limited effects on fatty acid ratios.

CONCLUSIONS

These randomized clinical trial data demonstrate the widespread effects of pravastatin treatment on lipoprotein subclass profiles and fatty acids.

CLINICAL TRIAL REGISTRATION

URL: http://www.clinicaltrials.gov. Unique identifier: NCT03073018.

Hypertriglyceridemia - Common Causes, Prevention and Treatment Strategies

BACKGROUND

Prevention and treatment of dyslipidemias represent the key issues of Cardiovascular Disease (CVD) prophylaxis. Consequently, the effective management of different types of lipid disorders, including hypertriglyceridemia, should be a priority for the healthcare practitioners (e.g.: cardiology and endocrinology specialists, primary care physicians, dietitians, and pharmacists), who provide medical care, as well as for the patients, who receive this care, and need to be directly engaged in it, in order to improve their outcomes. The aim of this review is to facilitate the translation of current trends in hypertriglyceridemia management into a daily practice. The article focuses on the common causes and consequences of hypertriglyceridemia, and discusses diagnostic evaluation and therapeutic options for patients with high Triglyceride (TG) levels and CVD risk.

CONCLUSION

This review presents the main practice-related strategies, based on the current guidelines for the management of dyslipidemias and CVD risk, according to the European Society of Cardiology (ESC), the European Atherosclerosis Society (EAS), and the American College of Cardiology (ACC)/American Heart Association (AHA), including both non-pharmacological, and pharmacological approaches. It also addresses the beneficial impact of pharmaceutical Care (PC) interventions on clinical outcomes of patients with lipid disorders and CVD risk (in light of Randomized Controlled Trials (RCT) data), and underlines the importance of close cooperation between physicians and pharmacists, who manage such patients.

Differential Effects of Lipid-lowering Drugs in Modulating Morphology of Cholesterol Particles

Treatment of dyslipidemia patients with lipid-lowering drugs leads to a significant reduction in low-density lipoproteins (LDL) level and a low to moderate level of increase in high-density lipoprotein (HDL) cholesterol in plasma. However, a possible role of these drugs in altering morphology and distribution of cholesterol particles is poorly understood. Here, we describe the in vitro evaluation of lipid-lowering drug effects in modulating morphological features of cholesterol particles using the plaque array method in combination with imaging flow cytometry. Image analyses of the cholesterol particles indicated that lovastatin, simvastatin, ezetimibe, and atorvastatin induce the formation of both globular and linear strand-shaped particles, whereas niacin, fibrates, fluvastatin, and rosuvastatin induce the formation of only globular-shaped particles. Next, purified very low-density lipoprotein (VLDL) and LDL particles incubated with these drugs showed changes in the morphology and image texture of cholesterol particles subpopulations. Furthermore, screening of 50 serum samples revealed the presence of a higher level of linear shaped HDL cholesterol particles in subjects with dyslipidemia (mean of 18.3%) compared to the age-matched normal (mean of 11.1%) samples. We also observed considerable variations in lipid-lowering drug effects on reducing linear shaped LDL and HDL cholesterol particles formation in serum samples. These findings indicate that lipid-lowering drugs, in addition to their cell-mediated hypolipidemic effects, may directly modulate morphology of cholesterol particles by a non-enzymatic mechanism of action. The outcomes of these results have potential to inform diagnosis of atherosclerosis and predict optimal lipid-lowering therapy.

Cardiac and Metabolic Variables in Obese Dogs

Background

The etiology of obesity‐related cardiac dysfunction (ORCD) is linked to metabolic syndrome in people. Studies have indicated that obese dogs have components of metabolic syndrome, warranting evaluation for ORCD in obese dogs.

Objectives

To evaluate cardiac structure and function and metabolic variables in obese dogs compared to ideal weight dogs.

Animals

Forty‐six healthy, small‐breed (<25 pounds), obese dogs (n = 29) compared to ideal weight dogs (n = 17).

Methods

A cross‐sectional study of cardiac structure and function by standard and strain echocardiographic measurements and quantification of serum metabolic variables (insulin:glucose ratios, lipid analysis, adiponectin, inflammatory markers).

Results

Compared to the ideal weight controls, obese dogs had cardiac changes characterized by an increased interventricular septal width in diastole to left ventricular internal dimension in diastole ratio, decreased ratios of peak early to peak late left ventricular inflow velocities, and ratios of peak early to peak late mitral annular tissue velocities, and increased fractional shortening and ejection fraction percentages. The left ventricular posterior wall width in diastole to left ventricular internal dimension in diastole ratios were not significantly different between groups. Systolic blood pressure was not significantly different between groups. Obese dogs had metabolic derangements characterized by increased insulin:glucose ratios, dyslipidemias with increased cholesterol, triglyceride, and high‐density lipoprotein concentrations, decreased adiponectin concentrations, and increased concentrations of interleukin 8 and keratinocyte‐derived chemokine‐like inflammatory cytokines.

Conclusions and Clinical Importance

Compared to ideal weight controls, obese dogs have alterations in cardiac structure and function as well as insulin resistance, dyslipidemia, hypoadiponectinemia, and increased concentrations of inflammatory markers. These findings warrant additional studies to investigate inflammation, dyslipidemia, and possibly systemic hypertension as potential contributing factors for altered cardiac function.

The Mediterranean Diet decreases LDL atherogenicity in high cardiovascular risk individuals: a randomized controlled trial

SCOPE

Traditional Mediterranean diet (TMD) protects against cardiovascular disease through several mechanisms such as decreasing LDL cholesterol levels. However, evidence regarding TMD effects on LDL atherogenic traits (resistance against oxidation, size, composition, cytotoxicity) is scarce.

METHODS AND RESULTS

We assessed the effects of a 1-year intervention with a TMD on LDL atherogenic traits in a random sub-sample of individuals from the PREDIMED study (N = 210). We compared two TMDs: one enriched with virgin olive oil (TMD-VOO, N = 71) and another with nuts (TMD-Nuts, N = 68), versus a low-fat control diet (N = 71). After the TMD-VOO intervention, LDL resistance against oxidation increased (+6.46%, p = 0.007), the degree of LDL oxidative modifications decreased (-36.3%, p<0.05), estimated LDL particle size augmented (+3.06%, p = 0.021), and LDL particles became cholesterol-rich (+2.41% p = 0.013) relative to the low-fat control diet. LDL lipoproteins became less cytotoxic for macrophages only relative to baseline (-13.4%, p = 0.019). No significant effects of the TMD-Nuts intervention on LDL traits were observed versus the control diet.

CONCLUSION

Adherence to a TMD, particularly when enriched with virgin olive oil, decreased LDL atherogenicity in high cardiovascular risk individuals. The development of less atherogenic LDLs could contribute to explaining some of the cardioprotective benefits of this dietary pattern.

Hypertriglyceridemia and Cardiovascular Outcomes

Cardiovascular disease, particularly ischemic heart disease, is one of the most common causes of morbidity and mortality in the United States. Atherosclerosis, the root cause of ischemic heart disease, is promoted by risk factors like elevated plasma low-density lipoprotein, low plasma high-density lipoprotein, smoking, hypertension, and diabetes mellitus. Even 66 years after a relation between triglycerides (TG) and cardiovascular disease was first suspected, TGs still continue to be a controversial risk factor and target for therapy. Some previous studies did not show any significant positive relationship between TG and cardiovascular mortality; however, recent meta-analyses found otherwise. The role of elevated TG in patients with low low-density lipoprotein and interventions to lower TG to reduce cardiovascular mortality and morbidity is an area of active research.

Enzyme-Linked Immunoassay-Based Quantitative Measurement of Apolipoprotein B (ApoB) in Dried Blood Spots, a Biomarker of Cardiovascular Disease Risk

Apolipoprotein B (ApoB) is a strong predictor of cardiovascular disease, which remains the leading cause of mortality in both higher and lower income countries. Here, we adapted an enzyme-linked immunosorbent assay (ELISA) development kit for quantitative determination of ApoB levels in serum and plasma for use with dried blood spots (DBS). After confirming the dilution linearity of the assay for DBS, we measured ApoB in 208 venous DBS samples. Then, using Passing-Bablok regression analysis and Spearman rank correlation analysis, we evaluated the correspondence in ApoB values between matched plasma and finger-prick DBS samples from 40 individuals who had ApoB values spanning the range of ApoB values observed in the 208 vDBS samples. We also evaluated assay precision and recovery, the effects of hematocrit, number of freeze-thaw cycles, and different storage temperatures on ApoB levels in DBS. There was a strong, significant correlation between plasma and DBS ApoB levels with little bias. Assay precision and recovery were within the range recommended by the U.S. government's industry guidelines for bioanalytical assay validation. The assay was not affected by the DBS matrix or physiological hematocrit levels. This DBS-based ELISA assay will facilitate population-scale assessment of cardiovascular risk in previously unexplored populations.

Reduced first-phase insulin secretion increases postprandial lipidemia in subjects with impaired glucose tolerance

OBJECTIVE

It is not clear which phase of insulin secretion is more important to regulate lipoprotein lipase (LPL) activity. After a meal, insulin is released and acts as a major regulator of LPL activity. Postprandial hyperlipidemia is a common comorbidity in subjects with insulin resistance (IR). Therefore this study aimed to evaluate the role of the first-phase insulin secretion (FPIS) on postprandial lipidemia in subjects with IR and impaired glucose tolerance (IGT).

RESEARCH DESIGN AND METHODS

This is a cross-sectional, observational and comparative study. We included male and female subjects between 40 and 60 years with a body mass index (BMI) between 23 and 30 kg/m². Then, patients were divided into three groups. Group 1 consisted of control subjects with normal glucose tolerance and preserved FPIS. Group 2 included patients with IGT and a reduced FPIS. Group 3 consisted of subjects with IGT but normal FPIS. Both groups were paired by age and BMI with subjects in the control group. Subjects underwent an intravenous glucose tolerance test to classify each case, and then a load with a mixed meal load to measure postprandial lipidemia.

RESULTS

A total of 32 subjects were evaluated: 10 were control subjects, 8 subjects with IGT with a reduced FPIS and 14 subjects with IGT and preserved FPIS. After administration of a standardized meal, group 2 showed a greater glucose area under the curve (AUC) at 30 and 120 min (p=0.001, for both). This group also showed a statistically significant increase (p<0.001) in triglyceride AUC.

CONCLUSIONS

A reduced FPIS is significantly and independently associated with a larger postprandial hyperlipidemia in subjects with IGT.

Relevance of the triglyceride-to-high-density lipoprotein cholesterol ratio as an important lipid fraction in apparently healthy, young, and middle-aged Indian men

CONTEXT

Cardiovascular disease (CVD) is the largest cause of mortality in Indians. Insulin resistance and related dyslipidemia of increased triglyceride (TG), small dense low-density lipoprotein (sd-LDL) particles, and decreased high-density lipoprotein-cholesterol (HDL-C) are associated with increased risk of CVD. TG/HDL-C ratio could be a potential surrogate marker for this South Asian phenotype. Data are scarce on the relevance of TG/HDL-C ratio as a useful lipid marker among Indians.

AIMS

To study the prevalence of TG/HDL-C ratio among healthy, young, and middle-aged Indian men (25-44 years) and its relationship with other lipid and nonlipid factors.

SUBJECTS AND METHODS

In this cross-sectional analysis, fasting blood samples from 236 healthy participants recruited from an urban community setting were tested for TG/HDL-C ratio, HDL-C, TG, total cholesterol (TC), non-HDL-C, TC/HDL-C, high-sensitivity C-reactive protein, body mass index (BMI), and body fat.

RESULTS

Mean (standard deviation) age of participants was 34.7 (7.7) years; median (interquartile range) TG/HDL-C ratio was 4 (2.85-5.2). More than half (51.3%) the participants (n = 121) recorded abnormal TG/HDL-C ratio (≥4.0). Across tertiles of TG/HDL-C ratio, there was a significant trend of higher conventional lipid parameters such as non-HDL-C*, TC/HDL-C ratio*, TG*, HDL-C*, TC**; and non-lipid parameters body-fat* and BMI*** (*P < 0.001, **P = 0.015, ***P = 0.002). LDL-C showed moderate and nonsignificant (P = 0.646) increase across tertiles.

CONCLUSION

In a sample of apparently healthy, young, and middle-aged Indian men abnormal TG/HDL-C ratio levels were observed among more than half the participants. The TG/HDL-C ratio was closely associated with other lipid parameters and measures of adiposity, such as BMI and body fat, apart from its previously documented unique association with sd-LDL particles. TG/HDL-C ratio should be evaluated in future for risk prediction of incident CVD among Indians.

Statin therapy and plasma free fatty acids: a systematic review and meta-analysis of controlled clinical trials

AIM

The aim of this meta-analysis was to evaluate the effect of statin therapy on plasma FFA concentrations in a systematic review and meta-analysis of controlled clinical trials.

METHODS

PubMed-Medline, SCOPUS, Web of Science and Google Scholar databases were searched (from inception to February 16 2015) to identify controlled trials evaluating the impact of statins on plasma FFA concentrations. A systematic assessment of bias in the included studies was performed using the Cochrane criteria. A random effects model and generic inverse variance method were used for quantitative data synthesis. Sensitivity analysis was conducted using the leave-one-out method. Random effects meta-regression was performed using unrestricted maximum likelihood method to evaluate the impact of potential moderators.

RESULTS

Meta-analysis of data from 14 treatment arms indicated a significant reduction in plasma FFA concentrations following treatment with statins (weighted mean difference (WMD) -19.42%, 95% CI -23.19, --15.64, P < 0.001). Subgroup analysis confirmed the significance of the effect with both atorvastatin (WMD -20.56%, 95% CI -24.51, -16.61, P < 0.01) and simvastatin (WMD -18.05%, 95% CI -28.12, -7.99, P < 0.001). Changes in plasma FFA concentrations were independent of treatment duration (slope -0.10, 95% CI -0.30, 0.11, P = 0.354) and magnitude of reduction in plasma low density lipoprotein cholesterol concentrations (slope 0.55, 95% CI -0.17, 1.27, P = 0.133) by statins.

CONCLUSIONS

The results of the present study suggest that statin therapy may lower plasma FFA concentrations. The cardiovascular and metabolic significance of this finding requires further investigation.

Cholesterol Metabolism in CKD

Patients with chronic kidney disease (CKD) have a substantial risk of developing coronary artery disease. Traditional cardiovascular disease (CVD) risk factors such as hypertension and hyperlipidemia do not adequately explain the high prevalence of CVD in CKD. Both CVD and CKD are inflammatory states and inflammation adversely affects lipid balance. Dyslipidemia in CKD is characterized by elevated triglyceride levels and high-density lipoprotein levels that are both decreased and dysfunctional. This dysfunctional high-density lipoprotein becomes proinflammatory and loses its atheroprotective ability to promote cholesterol efflux from cells, including lipid-overloaded macrophages in the arterial wall. Elevated triglyceride levels result primarily from defective clearance. The weak association between low-density lipoprotein cholesterol level and coronary risk in CKD has led to controversy over the usefulness of statin therapy. This review examines disrupted cholesterol transport in CKD, presenting both clinical and preclinical evidence of the effect of the uremic environment on vascular lipid accumulation. Preventative and treatment strategies are explored.

Exercise for obese youth: refocusing attention from weight loss to health gains

Despite evidence to the contrary, exercise interventions for obese youth target weight loss as a means of improving health. Using Exercise is Medicine® as a framework, we present a conceptual model for the beneficial effects of exercise independent of weight loss in obese youth and highlight novel biomarkers of cardiometabolic health that could prove useful as interventional targets for this population.

"Role of the adipocyte hormone leptin in cardiovascular diseases - a study from Chennai based Population"

Background

Obesity is currently regarded as a pro-inflammatory condition during which leptin (Ob gene product) might act as a risk factor for Cardiovascular Diseases (CVD) including Acute Myocardial Infarction (AMI). There is a marked increase in circulating leptin concentrations and inflammatory markers such as Tumor Necrosis Factor-α (TNF-α) in AMI patients but still the association of leptin with inflammation during AMI is not known. The present study suggest that elevated levels of leptin might elicit the risk for CVD by signaling for the secretion of inflammatory cytokines especially, TNF-α.

Methods

Blood samples were collected from 100 CVD subjects diagnosed for AMI immediately after their admission to the hospital and serum leptin, insulin, glucose, lipids and inflammatory marker such as TNF-α were measured. 5 ml random (non-fasting) blood was collected from 100 non-CVD (control) subjects and the results obtained in case of AMI subjects were compared with that of the control subjects. The subjects under study included both men and women belonging to the age group of 35 – 75 and they were classified based on their BMI as normal weight, overweight and obese.

Results

Circulating levels of leptin are found to be elevated in obese control subjects and in patients with AMI irrespective of their Body Mass Index (BMI). In addition, leptin is also found to be positively correlated to serum triglycerides, insulin and TNF-α in AMI subjects. MANOVA analysis suggests that leptin might influence the synthesis of insulin and TNF-α. This is the first report relating leptin to TNF-α in Chennai based population, India.

Conclusions

Hyperleptinemia might act as a risk marker for AMI. The present study suggests that at elevated levels, leptin may favor atherosclerosis by promoting the synthesis of TNF-α and insulin. However, our report warrants further investigation both in vitro and in vivo to determine the exact mechanism behind the pro-atherogenic role of leptin. The observed positive correlation between leptin and BMI in both AMI and control subjects suggests that obese subjects manifest leptin resistance and hence, they possess a greater risk for the incidence of CVD.

SORT1 Protective Allele Is Associated With Attenuated Postprandial

Background—

Elevated levels of lipids and lipoproteins have strong genetic determinants and are recognized as key risk factors for atherogenesis and cardiovascular disease, particularly in the postprandial state. The aim of the study to determine whether young adults, when stratified by genotype at the rs646776 variant of the 1p13 locus, displayed differential postprandial responses to an oral fat tolerance test.

Methods and Results—

Participants (n=30) received a high-fat mixed meal (91 g; 55% kcal from fat) after an overnight fast and a fat-exclusion meal (3.9 g; 6% kcal from fat) at 8 hours postprandially. Blood samples were obtained at t =0, 2, 4, 6, 8, and 24 hours for lipoprotein analyses via nuclear magnetic resonance profiling. Carriers of the minor, protective allele (TC/CC) displayed lower fasting (TC/CC, 30.1±3.0 nmol/L versus TT, 48.8±5.1 nmol/L; P <0.01) and mean postprandial (TC/CC, 44.2±3.1 nmol/L versus TT, 57.0±4.5 nmol/L; P =0.03) very low-density lipoprotein and chylomicron particle number in addition to triglyceride content when compared with individuals homozygous for the major, risk allele (TT).

Conclusions—

We report a novel association between the SORT1 1p13 locus and extent of postprandial lipaemia. These results provide evidence of decreased exposure to atherogenic particles in carriers of the minor SORT1 allele, suggesting relative protection against cardiovascular disease when compared with TT homozygotes.

A review on the traditional Chinese medicinal herbs and formulae with hypolipidemic effect

Hyperlipidemia, characterized by the abnormal blood lipid profiles, is one of the dominant factors of many chronic diseases such as diabetes, obesity, and cardiovascular diseases (CVD). For the low cost, effectiveness, and fewer side effects, the popularity of using traditional Chinese medicine (TCM) to handle hyperlipidemia is increasing and its role in health care has been recognized by the public at large. Despite the importance of TCM herbs and formulations, there is no comprehensive review summarizing their scientific findings on handling hyperlipidemia. This review summarizes the recent experimental and clinical results of nine representative single Chinese herbs and seven classic TCM formulae that could improve lipid profiles so as to help understand and compare their underlying mechanisms. Most of single herbs and formulae demonstrated the improvement of hyperlipidemic conditions with multiple and diverse mechanisms of actions similar to conventional Western drugs in spite of their mild side effects. Due to increasing popularity of TCM, more extensive, well-designed preclinical and clinical trials on the potential synergistic and adverse side effects of herb-drug interactions as well as their mechanisms are warranted. Hyperlipidemic patients should be warned about the potential risks of herb-drug interactions, particularly those taking anticoagulants and antiplatelet drugs.

Dietary intake of palmitate and oleate has broad impact on systemic and tissue lipid profiles in humans

BACKGROUND

Epidemiologic evidence has suggested that diets with a high ratio of palmitic acid (PA) to oleic acid (OA) increase risk of cardiovascular disease (CVD).

OBJECTIVE

To gain additional insights into the relative effect of dietary fatty acids and their metabolism on CVD risk, we sought to identify a metabolomic signature that tracks with diet-induced changes in blood lipid concentrations and whole-body fat oxidation.

DESIGN

We applied comprehensive metabolomic profiling tools to biological specimens collected from 18 healthy adults enrolled in a crossover trial that compared a 3-wk high-palmitic acid (HPA) with a low-palmitic acid and high-oleic acid (HOA) diet.

RESULTS

A principal components analysis of the data set including 329 variables measured in 15 subjects in the fasted state identified one factor, the principal components analysis factor in the fasted state (PCF1-Fasted), which was heavily weighted by the PA:OA ratio of serum and muscle lipids, that was affected by diet (P < 0.0001; HPA greater than HOA). One other factor, the additional principal components analysis factor in the fasted state (PCF2-Fasted), reflected a wide range of acylcarnitines and was affected by diet in women only (P = 0.0198; HPA greater than HOA). HOA lowered the ratio of serum low-density lipoprotein to high-density lipoprotein (LDL:HDL) in men and women, and adjustment for the PCF1-Fasted abolished the effect. In women only, adjustment for the PCF2-Fasted eliminated the HOA-diet effect on serum total- and LDL-cholesterol concentrations. The respiratory exchange ratio in the fasted state was lower with the HPA diet (P = 0.04), and the diet effect was eliminated after adjustment for the PCF1-Fasted. The messenger RNA expression of the cholesterol regulatory gene insulin-induced gene-1 was higher with the HOA diet (P = 0.008).

CONCLUSIONS

These results suggest that replacing dietary PA with OA reduces the blood LDL concentration and whole-body fat oxidation by modifying the saturation index of circulating and tissue lipids. In women, these effects are also associated with a higher production and accumulation of acylcarnitines, possibly reflecting a shift in fat catabolism.

Effect of Mediterranean Diet With and Without Weight Loss on Apolipoprotein B 100 Metabolism in Men With Metabolic Syndrome

Objective—

To assess the effect of a Mediterranean diet (MedDiet) with and without weight loss (WL) on apolipoprotein B 100 (apoB 100 ) metabolism in men with metabolic syndrome.

Approach and Results—

The diet of 19 men with metabolic syndrome (age, 24–62 years) was first standardized to a North American isoenergetic control diet for 5 weeks, followed by an isoenergetic MedDiet for an additional 5 weeks under full-feeding conditions (MedDiet−WL). Participants next underwent a 20-week supervised WL program under free-living conditions (−10.2±2.9% body weight; P <0.01) and finally consumed the MedDiet (5 weeks) under weight-stabilizing feeding conditions (MedDiet+WL). In vivo kinetic of apoB 100 was assessed in the fasted state at the end of the 3 controlled diets using a bolus of D 3 -leucine. Compared with the control diet, MedDiet−WL reduced low-density lipoprotein (LDL)-apoB 100 pool size (−14.2%, P <0.01) primarily through an increase in LDL-apoB 100 fractional catabolic rate (+30.4%, P =0.02) and increased LDL particle size ( P <0.01) but had no effect on very-LDL (VLDL)-apoB 100 pool size or triglyceride concentrations, despite a significant increase in VLDL-apoB 100 fractional catabolic rate (+25.6%; P =0.03). MedDiet+WL had no further effect on LDL-apoB 100 pool size and fractional catabolic rate but further increased LDL particle size and reduced VLDL-apoB 100 pool size versus the control diet primarily through an increase in VLDL-apoB 100 fractional catabolic rate (+30.7%; P <0.01).

Conclusions—

Consumption of MedDiet increases LDL size and reduces LDL-apoB 100 concentrations primarily by increasing the catabolism of LDL even in the absence of WL in men with metabolic syndrome. MedDiet seems to have a trivial effect on VLDL concentrations and kinetics unless accompanied by significant WL.

Clinical Trial Registration

—URL: http://www.clinicaltrials.gov . Unique identifier: NCT00988650.

Association between urinary albumin excretion and low-density lipoprotein heterogeneity following treatment of type 2 diabetes patients with the dipeptidyl peptidase-4 inhibitor, vildagliptin: a pilot study

BACKGROUND

Few data exist as to whether dipeptidyl peptidase (DPP)-4 inhibitors affect cardio-renal interaction, which is a strong independent prognostic factor for cardiovascular disease (CVD), in diabetic patients. We evaluated the effects of a DPP-4 inhibitor on atherogenic low-density lipoprotein (LDL) heterogeneity and albuminuria in diabetics as an indicator of the severity of diabetic nephropathy.

METHODS

Type 2 diabetes patients (n = 47) inadequately controlled with diabetes therapy were treated with vildagliptin 50 mg bid for 8 weeks. LDL heterogeneity was evaluated on the basis of the patients' small dense (sd) LDL levels and sd-LDL proportion (sd-LDL/LDL cholesterol [LDL-C]). The level of albuminuria was evaluated on the basis of the urinary albumin-to-creatinine ratio (UACR).

RESULTS

After 8 weeks of treatment, there was no significant change in serum LDL-C level, but the serum sd-LDL level had decreased significantly by 8.8 %, and the UACR had also decreased significantly by 44.6 %. Triglyceride (TG)-metabolism-related markers (TG, remnant-like particle cholesterol, apolipoprotein [apo] B, apoC-2, and apoC-3) had decreased significantly. The Δ (absolute change from baseline) sd-LDL values correlated positively with ΔTG-metabolism-related markers, but not with the Δ hemoglobin (Hb) A1c or Δ fasting blood sugar (ΔFBS). Furthermore, multivariate regression analysis revealed that Δsd-LDL proportion, but not ΔHbA1c or ΔFBS, was an independent predictor of ΔUACR (β = 0.292, p = 0.0016).

CONCLUSIONS

Although this was a single-arm study, treatment of type 2 diabetes with vildagliptin might prevent the progression of CVD complicating diabetes by improving LDL heterogeneity, and it might improve renal function by decreasing albuminuria. A randomized controlled trial is warranted.

Diagnosis and management of familial dyslipoproteinemias

The three major pathways of lipoprotein metabolism provide a superb paradigm to delineate systematically the familial dyslipoproteinemias. Such understanding leads to improved diagnosis and treatment of patients. In the exogenous (intestinal) pathway, defects in LPL, apoC-II, APOA-V, and GPIHBP1 disrupt the catabolism of chylomicrons and hepatic uptake of their remnants, producing very high TG. In the endogenous (hepatic) pathway, six disorders affect the activity of the LDLR and markedly increase LDL. These include FH, FDB, ARH, PCSK9 gain-of-function mutations, sitosterolemia and loss of 7 alpha hydroxylase. Hepatic overproduction of VLDL occurs in FCHL, hyperapoB, LDL subclass pattern B, FDH and syndrome X, often due to insulin resistance and resulting in high TG, elevated small LDL particles and low HDL-C. Defects in APOB-100 and loss-of-function mutations in PCSK9 are associated with low LDL-C, decreased CVD and longevity. An absence of MTP leads to marked reduction in chylomicrons and VLDL, causing abetalipoproteinemia. In the reverse cholesterol pathway, deletions or nonsense mutations in apoA-I or ABCA1 transporter disrupt the formation of the nascent HDL particle. Mutations in LCAT disrupt esterification of cholesterol in nascent HDL by LCAT and apoA-1, and formation of spherical HDL. Mutations in either CETP or SR-B1 and familial high HDL lead to increased large HDL particles, the effect of which on CVD is not resolved. The major goal is to prevent or ameliorate the major complications of many familial dyslipoproteinemias, namely, premature CVD or pancreatitis. Dietary and drug treatment specific for each inherited disorder is reviewed.

LOW-DENSITY LIPOPROTEIN SUBFRACTIONS AND VARYING DEGREE OF CORONARY STENOSIS

Aim.To investigate whether low and intermediate density lipoprotein (LDL, IDL) subfractions are associated with a degree of angiographically verified coronary atherosclerosis, as well as with other biochemical risk factors of coronary heart disease (CHD), and hypertriglyceridemia (HTG) in particular.

Material and methods.The study included 129 patients (76 men and 53 women), aged 33–75 years, who were referred for coronary angiography. All participants were divided into three groups by the degree of coronary artery (CA) stenosis: 0–20%, 21–70%, and >70%. LDL and IDL subfractions were measured with the Lipoprint LDL System (electrophoresis in 3% polyacrylamide gel).

Results.All groups were similar by the levels of lipid and apoprotein parameters. The levels of high-sensitive C-reactive protein and glucose, as well as HOMA-IR index, were higher in Group 3 patients. In most cases of severe CA stenosis, small dense LDL particles were detected. In HTG patients, higher levels of small dense LDL3 particles were registered only together with the CA stenosis of at least 21–70%.

Conclusion.The findings on lipoprotein subfractions, obtained with the Lipoprint LDL System, have demonstrated that in patients with verified coronary atherosclerosis, there is a link between the levels of more atherogenic small dense LDL3 particles, the degree of CA stenosis, and blood TG levels. The combination of HTG and high LDL3 levels could be considered an additional marker of severe CA atherosclerosis. 

The Role of Endocannabinoid System Blockade in the Treatment of the Metabolic Syndrome

This review considers the use of the first selective blocker of the cannabinoid receptor type 1, rimonabant, to reduce weight and improve cardiovascular disease risk factors in obese patients with metabolic syndrome or multiple cardiovascular disease risk factors. In 4 large trials-Rimonabant in Obesity (RIO)-Lipids, RIO-Europe, RIO-North America, and RIO-Diabetes-after 1 to 2 years of treatment, rimonabant (20 mg/day) led to a significantly greater weight loss and reduction in waist circumference compared with placebo. Treatment with rimonabant was also associated with other favorable changes, including better glycemic control in type 2 diabetes mellitus, improved lipid profile, reduced blood pressure, increased adiponectin levels, fall in high-sensitivity C-reactive protein concentrations, and an overall decrease in the prevalence of the metabolic syndrome. Initial experience with rimonabant shows that it is generally well tolerated with the most common side effect of mild nausea. Rimonabant may be a useful adjunct to lifestyle and behavior modification in the treatment of obese subjects with metabolic syndrome or multiple cardiometabolic risk factors.

Study design, rationale, and baseline characteristics: evaluation of fenofibric acid on carotid intima-media thickness in patients with type IIb dyslipidemia with residual risk in addition to atorvastatin therapy (FIRST) trial

PURPOSE

Elevated triglycerides (TG) and low high-density lipoprotein cholesterol (HDL-C) levels contribute to cardiovascular disease risk and can be effectively treated with fenofibric acid. A trial is under way to evaluate the effect of once-daily fenofibric acid or placebo on carotid intima-media thickness (CIMT) progression in patients with controlled low-density lipoprotein cholesterol (LDL-C) levels achieved through atorvastatin treatment, but with high TG and low HDL-C levels.

METHODS

In this multicenter, double-blind study, 682 patients were randomized to once-daily delayed-release capsules of choline fenofibrate 135 mg (fenofibric acid [Trilipix(®); Abbott, North Chicago, IL]) or placebo plus atorvastatin treatment after a 2- to 10-week diet and atorvastatin run-in period. Key inclusion criteria included age ≥45 years; posterior-wall common CIMT ≥0.7 mm on at least one side at baseline; fasting results of TG ≥150 mg/dL, and HDL-C ≤45 mg/dL for men or HDL-C ≤55 mg/dL for women at screening while receiving atorvastatin; controlled LDL-C; and known coronary heart disease (CHD) or a CHD risk equivalent. The primary efficacy variable is the rate of change from baseline through week 104 in the mean posterior-wall intima-media thickness of the common carotid arteries (composite value of left and right sides).

CONCLUSIONS

This trial is the first to examine the effect of fenofibric acid on CIMT and the first CIMT trial to select patients with controlled LDL-C and elevated TG and low HDL-C as inclusion criteria. Also, this trial will prospectively evaluate the effect of treatment on LDL particles and address shortcomings of previous CIMT trials.

The triglyceride/high-density lipoprotein cholesterol ratio, the small dense low-density lipoprotein phenotype, and ischemic heart disease risk

This study investigated the relevance of using the plasma triglyceride to high-density lipoprotein cholesterol ratio (Log TG/HDL-C) for the prediction of the small dense lowdensity lipoprotein (LDL) phenotype and the risk of ischemic heart disease (IHD). Analyses were based on data from the Quebec Cardiovascular Study in a cohort of 2072 men free of IHD at baseline, among whom 262 had a first IHD event (coronary death, non fatal myocardial infarction and unstable angina) during a 13-year follow-up period. LDL particle size phenotype was characterized using 2-16% polyacrylamide gradient gel electrophoresis (PAGGE) of whole plasma. There were significant associations between the Log TG/HDL-C ratio and features of LDL size phenotype such as the proportion of LDL with a diameter <255A (r = 0.43, p < 0.001) and LDL peak particle size (r = -20.55, p < 0.001). However, the Log TG/HDL-C ratio brought no additional value (p â yen 0.1) in predicting the small dense LDL phenotype (area under the receiver operating curve (AUROC = 71.9%) compared to TG alone (AUROC = 71.2%) or to a combination of Log TG and HDL-C (AUROC = 72.4%) after multivariate adjustment for non lipid risk factors. Finally, elevations in the Log TG/HDL-C ratio did not improve the discrimination of incident IHD cases from non IHD cases compared to the use of plasma TG levels alone (p = 0.5) or a combination of the individual TG and HDL-C values (p = 0.5). The Log TG/HDL-C ratio does not improve our ability to identify individuals with the small dense LDL phenotype compared to plasma TG levels alone. The Log TG/HDLC is also not superior to plasma TG levels alone in predicting IHD risk in men of the QuA(c)bec Cardiovascular Study.

Kinetic analysis of thermal stability of human low density lipoproteins: a model for LDL fusion in atherogenesis

Fusion of modified LDL in the arterial wall promotes atherogenesis. Earlier we showed that thermal denaturation mimics LDL remodeling and fusion, and revealed kinetic origin of LDL stability. Here we report the first quantitative analysis of LDL thermal stability. Turbidity data show sigmoidal kinetics of LDL heat denaturation, which is unique among lipoproteins, suggesting that fusion is preceded by other structural changes. High activation energy of denaturation, E(a) = 100 ± 8 kcal/mol, indicates disruption of extensive packing interactions in LDL. Size-exclusion chromatography, nondenaturing gel electrophoresis, and negative-stain electron microscopy suggest that LDL dimerization is an early step in thermally induced fusion. Monoclonal antibody binding suggests possible involvement of apoB N-terminal domain in early stages of LDL fusion. LDL fusion accelerates at pH < 7, which may contribute to LDL retention in acidic atherosclerotic lesions. Fusion also accelerates upon increasing LDL concentration in near-physiologic range, which likely contributes to atherogenesis. Thermal stability of LDL decreases with increasing particle size, indicating that the pro-atherogenic properties of small dense LDL do not result from their enhanced fusion. Our work provides the first kinetic approach to measuring LDL stability and suggests that lipid-lowering therapies that reduce LDL concentration but increase the particle size may have opposite effects on LDL fusion.

Drug treatment of obesity in cardiovascular disease

Obesity is a significant health problem worldwide and is associated with a number of co-morbidities including type 2 diabetes mellitus, hypertension, dyslipidemia, obstructive sleep apnea, and cardiovascular disease. A number of different pathophysiologic mechanisms including increased inflammation, oxidative stress, and insulin resistance have been associated with initiation and progression of atherosclerotic disease in obese individuals. Lifestyle modifications have provided modest results in weight reduction and the focus of interest has now shifted towards drug development to treat severely obese individuals with a body mass index (BMI) >30 kg/m(2) or those with a BMI >27 kg/m(2) who have additional co-morbidities. Different regimens focusing on dietary absorption or acting centrally to control hunger and food intake have been developed. However, their weight loss effect is, in most cases, modest and this effect is lost once the medication is discontinued. In addition, long-term use of these drugs is limited by significant side effects and lack of long-term safety and efficacy data. Orlistat is the only US FDA-approved medication for long-term use. A number of new medications are currently under investigation in phase III trials with promising preliminary results. This review comments on available anti-obesity pharmacologic regimens, their weight-loss benefit, and their impact on cardiovascular risk factors.

The effect of EPA and DHA on metabolic syndrome patients: a systematic review of randomised controlled trials

Metabolic syndrome (MS) is characterised by accumulation of CVD risk factors. The use of very long chain n-3 polyunsaturated fatty acids (VLC n3 PUFA) could potentially benefit MS by reducing risk factors. To better understand the possible VLC n3 PUFA benefits, the literature was systematically reviewed for randomised controlled trials (RCT) that published effects of VLC n3 PUFA on MS patients. 17 RCT fulfilled the inclusion criteria and were analysed for relevance to the research question. The available RCT convincingly show that the administration of VLC n3 PUFA doses > 1 g for at least 3 months produces a significant reduction of triglycerides ranging from 7 % to 25 %. These results confirm the hypotriglyceridemic effect of VLC n3 PUFA in MS patients. The triglyceride lowering may produce further benefits by reducing the % of pro-atherogenic small dense LDL particles (sdLDL) and also perhaps by ameliorating the inflammatory process associated with MS. High doses of VLC n3 PUFA ( ≥ 3 g/day) may produce further TAG reductions but could raise other risk factors such as LDL-C. No clear effects were found on other MS markers. The combination of VLC n3 PUFA plus a statin may be useful to prevent the occurrence of coronary events. More studies are needed using different amounts of VLC n3 PUFA, time lengths, dietary backgrounds and different profiles of MS patients before clear recommendations can be made.

Effect of short-term low- and high-fat diets on low-density lipoprotein particle size in normolipidemic subjects

High-fat, low-carbohydrate diets have been shown to raise plasma cholesterol levels, an effect associated with the formation of large low-density lipoprotein (LDL) particles. However, the impact of dietary intervention on time-course changes in LDL particle size has not been investigated. To test whether a short-term dietary intervention affects LDL particle size, we conducted a randomized, double-blind, crossover study using an intensive dietary modification in 12 nonobese healthy men with normal plasma lipid profile. Participants were subjected to 2 isocaloric 3-day diets: high-fat diet (37% energy from fat and 50% from carbohydrates) and low-fat diet (25% energy from fat and 62% from carbohydrates). Plasma lipid levels and LDL particle size were assessed on fasting blood samples after 3 days of feeding on each diet. The LDL particles were characterized by polyacrylamide gradient gel electrophoresis. Compared with the low-fat diet, plasma cholesterol, LDL cholesterol, and high-density lipoprotein cholesterol were significantly increased (4.45 vs 4.78 mmol/L, P = .04; 2.48 vs 2.90 mmol/L, P = .005; and 1.29 vs 1.41 mmol/L, P = .005, respectively) following the 3-day high-fat diet. Plasma triglycerides and fasting apolipoprotein B-48 levels were significantly decreased after the high-fat diet compared with the low-fat diet (1.48 vs 1.01 mmol/L, P = .0003 and 9.6 vs 5.5 mg/L, P = .008, respectively). The high-fat diet was also associated with a significant increase in LDL particle size (255.0 vs 255.9 Å;P = .01) and a significant decrease in the proportion of small LDL particle (<255.0 Å) (50.7% vs 44.6%, P = .01). As compared with a low-fat diet, the cholesterol-raising effect of a high-fat diet is associated with the formation of large LDL particles after only 3 days of feeding.