Beyond LDL cholesterol reduction

Comparative predictive efficacy of atherogenic indices on metabolic syndrome in patients with schizophrenia

BACKGROUND

Schizophrenia patients endure high risks of metabolic syndrome and related cardiovascular mortality. Evidence on comparing detective power among atherogenic indices of the metabolic syndrome in schizophrenia patients with antipsychotics treatment is still lacking.

METHOD

We recruited 128 schizophrenia patients and collected blood samples to determine plasma levels of fasting glucose, total cholesterol, triglycerides (TG), high-density lipoprotein cholesterol (HDL-C) and low-density lipoprotein cholesterol. Five components of metabolic syndrome were assessed. Atherogenic indices, such as atherogenic index of plasma (AIP), atherogenic coefficient (AC), Castelli's risk index-I (CRI-I) and Castelli's risk index-II (CRI-II), were calculated. The area under the receiver operating characteristics curve (AUC) and regression analysis were adopted to compare the detective power of each atherogenic index for metabolic syndrome. The optimal cutoff points using maximization of Youden's index and the positive likelihood ratios were calculated.

RESULTS

51 (39.8 %) had metabolic syndrome. AIP (0.2 ± 0.2 vs. 0.6 ± 0.2), AC (2.5 ± 0.9 vs. 3.4 ± 0.9), CRI-I (3.5 ± 0.9 vs. 4.4 ± 0.9,) and CRI-II (2.1 ± 0.7 vs. 2.6 ± 0.7) were higher in the group with metabolic syndrome (all p < 0.001). AIP had the highest AUC (0.845, 95 % CI: 0.770, 0.920). The optimal cut-off point of AIP to predict metabolic syndrome was 0.4 with the corresponding sensitivity 83.7 %, specificity 80.3 %, and positive likelihood ratio 4.2. Regression analysis revealed that only AIP significantly correlated with the metabolic syndrome (p < 0.001).

CONCLUSION

Among atherogenic indices, only AIP has superior discrimination for detecting metabolic syndrome in schizophrenia with antipsychotics treatment.

Exploring the Association between Low-Density Lipoprotein Subfractions and Major Adverse Cardiovascular Outcomes—A Comprehensive Review

Cardiovascular disease (CVD) impacts hundreds of millions of people each year and is the main cause of death worldwide, with atherosclerosis being its most frequent form of manifestation. Low-density lipoproteins (LDL) have already been established as a significant cardiovascular risk factor, but more recent studies have shown that small, dense LDLs are the ones more frequently associated with a higher overall risk for developing atherosclerotic cardiovascular disease. Ever since atherogenic phenotypes were defined for the first time, LDL subfractions have been continuously analyzed in order to identify those with a higher atherogenic profile that could further become not only high-accuracy, effective prognostic biomarkers, but also treatment targets for novel lipid-lowering molecules. This review sets out to comprehensively evaluate the association between various LDL-subfractions and the risk of further developing major adverse cardiovascular events, by assessing both genetical and clinical features and focusing on their physiopathological characteristics, chemical composition, and global ability to predict long-term cardiovascular risk within the general population. Further research is required in order to establish the most beneficial range of LDL-C levels for both primary and secondary prevention, as well as to implement LDL subfraction testing as a routine protocol, separately from the general assessment of the other traditional cardiovascular risk factors.

Lipoproteins and Cardiovascular Disease: An Update on the Clinical Significance of Atherogenic Small, Dense LDL and New Therapeutical Options

Dyslipidemia is a potent risk factor for the genesis and progression of cardiovascular disease (CVD), and both the concentration and type of low-density lipoproteins (LDL) augment this association. The small, dense LDL (sdLDL) subfraction is the subtype which is most strongly predictive of atherosclerosis and cardiovascular events. In addition to the traditionally available lipid-lowering treatment options, certain novel therapies have been shown to favorably impact sdLDL, among them the antidiabetic class of agents known as glucagon-like peptide 1 receptor agonists (GLP1-RAs). These drugs seem to alter the pathophysiologic mechanisms responsible for the formation and accumulation of atherogenic lipoprotein particles, thus potentially reducing cardiovascular outcomes. They represent a uniquely targeted therapeutic approach to reduce cardiometabolic risk and warrant further study for their beneficial nonglycemic actions.

Atherogenic index of plasma as predictors for metabolic syndrome, hypertension and diabetes mellitus in Taiwan citizens: a 9-year longitudinal study

Deeply involved with dyslipidemia, cardiovascular disease has becoming the leading cause of mortality since the early twentieth century in the modern world. Whose correlation with metabolic syndrome (MetS), hypertension and type 2 diabetes mellitus (T2DM) has been well established. We conducted a 9-year longitudinal study to identify the association between easily measured lipid parameters, future MetS, hypertension and T2DM by gender and age distribution. Divided into three groups by age (young age: < 40, middle age: ≥ 40 and < 65 and old age: ≥ 65), 7670 participants, receiving standard medical inspection at Tri-Service General Hospital (TSGH) in Taiwan, had been enrolled in this study. Atherogenic index of plasma (AIP) was a logarithmically transformed ratio of triglyceride (TG)/high-density lipoprotein cholesterol (HDL-C). Through multivariate regression analyses, the hazard ratio (HR) of AIP for MetS, hypertension and T2DM were illustrated. AIP revealed significant association with all the aforementioned diseases through the entire three models for both genders. Additionally, AIP revealed significant correlation which remained still after fully adjustment in MetS, hypertension, and T2DM groups for subjects aged 40–64-year-old. Nevertheless, for participants aged above 65-year-old, AIP only demonstrated significant association in MetS group. Our results explore the promising value of AIP to determine the high-risk subjects, especially meddle-aged ones, having MetS, hypertension, and T2DM in the present and the future.

Atherogenic index of plasma is related to arterial stiffness but not to blood pressure in normotensive and never-treated hypertensive subjects

BACKGROUND AND AIMS

Atherogenic index of plasma (AIP), defined as the logarithm of triglycerides to high-density lipoprotein cholesterol (HDL-C) ratio, is a strong predictor of future cardiovascular disease. Our aim was to examine the association of AIP with haemodynamic variables in normotensive and never-treated hypertensive subjects in a cross-sectional study.

METHODS

Supine haemodynamics in 615 subjects without antihypertensive and lipid-lowering medications were examined using whole-body impedance cardiography and radial pulse wave analysis. Linear regression analysis was applied to investigate the association of AIP with haemodynamic variables and age, sex, body mass index (BMI), smoking status, alcohol consumption, plasma C-reactive protein, electrolytes, uric acid, low density lipoprotein cholesterol (LDL-C), estimated glomerular filtration rate, and quantitative insulin sensitivity check index.

RESULTS

The demographics and laboratory values of the study population were (mean ± 95% confidence interval): age 44.9 ± 1.0 years, BMI 26.8 ± 0.4 kg/m², office blood pressure 140.6 ± 1.6/89.4 ± 1.0 mmHg, total cholesterol 5.2 ± 0.08, LDL-C 3.1 ± 0.08, triglycerides 1.2 ± 0.08, HDL-C 1.6 ± 0.04 mmol/l, and AIP -0.15 ± 0.02. Age (standardized coefficient Beta 0.508, p < .001) and aortic systolic blood pressure (Beta 0.239, p < .001) presented with the strongest associations with pulse wave velocity. However, AIP was also associated with pulse wave velocity (Beta 0.145, p < .001). AIP was not related with aortic or radial blood pressure, cardiac output, systemic vascular resistance, or augmentation index.

CONCLUSIONS

AIP is directly and independently associated with arterial stiffness, a variable strongly related to cardiovascular risk. This supports more widespread use of AIP in standard clinical cardiovascular disease risk evaluation.

Effects of a High-Protein Diet Including Whole Eggs on Muscle Composition and Indices of Cardiometabolic Health and Systemic Inflammation in Older Adults with Overweight or Obesity: A Randomized Controlled Trial

Age-related increases in intermuscular adipose tissue (IMAT) impair muscle quality, decrease functional capacity, and promote several cardiometabolic and inflammatory disorders. Whether these age-related alterations in muscle composition improve by consuming a high-protein (HP) diet with whole eggs are unclear. This parallel-design, randomized-controlled trial assessed the effects of a 12-week eucaloric HP diet with three whole eggs per day (1.4 g protein kg⁻¹ day⁻¹) versus a normal-protein diet void of eggs (NP, 0.8 g protein kg⁻¹ day⁻¹) on muscle composition (IMAT), cardiometabolic health, and systemic inflammation in older adults with overweight or obesity (12 men and 10 women; age 70 ± 5 years, BMI 31.3 ± 3.2 kg/m², mean ± SD). No changes in muscle composition were observed over time, independent of protein intake. Total body weight was reduced in both groups (−3.3 ± 1.2%) and lean mass was preserved only with the HP diet. LDL concentration and hip circumference decreased only with the NP diet, while MCP-1 and HsCRP concentrations increased over time in both groups. A HP diet with whole eggs promotes lean mass retention with modest weight loss, but does not positively influence muscle composition, cardiometabolic health or systemic inflammation, compared to a NP diet void of eggs.

Zinc supplementation in prediabetes: A randomized double-blind placebo-controlled clinical trial

BACKGROUND

This study evaluated the effects of zinc supplementation on glycemic control, other cardiometabolic and anthropometric parameters, and disease progression in prediabetes.

METHODS

A randomized double-blind placebo-controlled Phase 2 clinical trial was conducted over a 12-month period in 200 subjects (43% male; mean [± SD] age 51.8 ± 7.3 years), randomly assigned (1:  1) to the treatment or control group. The treatment group received zinc (20 mg daily). Subjects were evaluated at baseline and at 1, 3, 6, and 12 months. The primary outcome was the change in glycemic control from baseline. Multiple regression analyses were performed, with change in outcome variables after intervention from baseline used as continuous dependent variables.

RESULTS

In both groups, mean serum zinc concentrations prior to the trial were below normal (15.29-21.41 μmol/L). During the 12-month follow-up, a significantly higher percentage of participants developed type 2 diabetes in the control compared with zinc-treated group (25.0% vs 11.0% respectively; P = 0.016). Fasting plasma glucose (FPG), 2-h glucose levels in the oral glucose tolerance test (OGTT), homeostasis model assessment of insulin resistance (HOMA-IR), total cholesterol (TC), and low-density lipoprotein cholesterol (LDL-C) were significantly lower in the treated group, with significant improvement in β-cell function. In all four regression models, the best predictor of the dependent variables (i.e. change in FPG, 2-h glucose in the OGTT, HOMA-IR, and homeostatic model assessment of β-cell function) was zinc treatment.

CONCLUSIONS

Zinc supplementation reduced blood glucose and insulin resistance while improving β-cell function. Furthermore, supplementation reduced disease progression to diabetes and had beneficial effects on TC and LDL-C.

The Ratio of Eicosapentaenoic Acid (EPA) to Arachidonic Acid may be a Residual Risk Marker in Stable Coronary Artery Disease Patients Receiving Treatment with Statin Following EPA Therapy

BACKGROUND

We investigated the relationship between the eicosapentaenoic acid (EPA)/arachidonic acid (AA) ratio and non-high-density lipoprotein cholesterol (non-HDL-C) level, a major residual risk of coronary artery disease (CAD), in statin-treated CAD patients following EPA therapy.

METHODS

We conducted a 6-month, prospective, randomized clinical trial to investigate the effect of the additional administration of EPA on the EPA/AA ratio and the serum non-HDL-C level in stable CAD patients receiving statin treatment. We assigned CAD patients already receiving statin therapy to an EPA group (1800 mg/day; n = 50) or a control group (n = 50).

RESULTS

A significant reduction in the serum non-HDL-C level was observed in the EPA group, compared with the control group (-9.7 vs. -1.2%, p = 0.01). A multiple-regression analysis with adjustments for coronary risk factors revealed that achieved EPA/AA ratio was more reliable as an independent and significant predictor of a reduction in the non-HDL-C level at a 6-month follow-up examination (β = -0.324, p = 0.033) than the absolute change in the EPA/AA ratio. Interestingly, significant negative correlations were found between the baseline levels and the absolute change values of both non-HDL-C and triglyceride-rich lipoproteins, both markers of residual risk of CAD, indicating that patients with a higher baseline residual risk achieved a greater reduction.

CONCLUSION

The present results suggest that the achieved EPA/AA ratio, but not the absolute change in EPA/AA ratio, following EPA therapy might be a useful marker for the risk stratification of CAD among statin-treated patients with a high non-HDL-C level.

CLINICAL TRIAL REGISTRATION

UMIN ( http://www.umin.ac.jp/ ) Study ID: UMIN000010452.

Oxidative Stress: An Effective Prognostic Tool for an Early Detection of Cardiovascular Disease in Menopausal Women

Background. Menopause, a form of reproductive aging, is marked by many hormonal variations which cause imbalance in the oxidative processes resulting in onset of endothelial dysfunction leading to cardiovascular disease (CVD). We aimed to analyze the effect of oxidative stress in an early detection of CVD in all menopausal women both normolipidemic and hyperlipidemic. Methods and Results. Study included 523 menopausal women (265 CVD and 258 non-CVD). They were screened for lipid profile, serum malondialdehyde (MDA), serum LDL carbonyl protein, and serum superoxide dismutase (SOD). Pearson's correlation was observed between MDA and atherogenic index of plasma (AIP) in both normolipidemic (r = 0.650; p < 0.001) and hyperlipidemic (r = 0.207; p < 0.01) CVD group as compared to non-CVD menopausal women. Significant correlation was also observed between LDL carbonyl content and AIP in normolipidemic (r = 0.650; p < 0.001) and hyperlipidemic (r = 0.248; p < 0.01) CVD menopausal women as compared to non-CVD ones. Conclusion. Strong correlation between atherogenic index of plasma and oxidative stress in CVD menopausal women reveals oxidative stress as an effective prognostic tool for an early detection of cardiovascular risk.

Effects of Zinc supplementation on serum lipids: a systematic review and meta-analysis

Zinc is a mineral that plays a vital role in many biological processes and plays an important role in insulin action and carbohydrate metabolism. It may also have a protective role in the prevention of atherogenesis. Numerous studies have evaluated the effects of Zinc supplementation on serum lipids in humans and have demonstrated varying results. We systematically evaluated the literature and performed a meta-analysis on the effects of Zinc supplementation on serum lipids. A five staged comprehensive search of the literature was conducted in the following databases; PubMed, Web of Science and SciVerse Scopus for studies published before 31st December 2014. All controlled clinical trial in humans, that included a Zinc supplement intervention, either alone or in combination with other micronutrients and evaluated effects on serum lipids (total cholesterol [TC], triglycerides [TG], LDL cholesterol [LDL-c] and HDL cholesterol [HDL-c]). A meta-analysis of selected studies was performed using RevMan v5.3. The Jaded scale was used to assess the methodological quality of the trials included in the systematic review. A total of 24 studies were included in Meta analysis, which included a total of 33 Zinc interventions, in a total of 14,515 participants in the Zinc intervention or control group. The duration of Zinc supplementation ranged from 1 month to 7.5 years. The dose of elemental Zinc supplemented ranged from 15–240 mg/day. The pooled mean difference for TC between Zinc supplemented and placebo groups from random effects analysis was −10.92 mg/dl (95 % CI: −15.33, −6.52; p < 0.0001, I² = 83 %), while for HDL cholesterol it was 2.12 mg/dl (95 % CI: −0.74, 4.98; p = 0.15, I² = 83 %). The pooled mean difference for LDL-c between Zinc supplemented and placebo group from random effect analysis was −6.87 mg/dl (95 % CI: −11.16,-2.58; p < 0.001, I² = 31) and for TG it was −10.92 mg/dl (95 % CI: −18.56, − 3.28; p < 0.01, I² = 69 %). In conclusion, Zinc supplementation has favourable effects on plasma lipid parameters. Zinc supplementation significantly reduced total cholesterol, LDL cholesterol and triglycerides. Therefore it may have the potential to reduce the incidence of atherosclerosis related morbidity and mortality.

The apolipoprotein B/apolipoprotein A-I ratio as a potential marker of plasma atherogenicity

Background. The apolipoprotein (apo) B/apoA-I ratio represents the balance between apoB-rich atherogenic particles and apoA-I-rich antiatherogenic particles, and this ratio is considered to be a marker of cardiovascular risk. Although many studies have demonstrated the importance of the apoB/apoA-I ratio in predicting the presence or absence of cardiovascular disease, less is known about apoB/apoA-I ratio as a marker of plasma atherogenicity. Methods. A total of 157 normolipidemic men aged 20–59 years were included in the study. The plasma levels of total cholesterol (TC), triglycerides (TG), high-density lipoprotein cholesterol (HDL-C), apoA-I, apoB, and apoE were determined after a 12 h fasting period. Results. The median of the apoB/apoA-I ratio in the studied normolipidemic subjects was 0.52, with values ranging from 0.19 to 2.60. The percentage of subjects with the apoB/apoA-I ratio exceeding 0.9 (the accepted risk value of cardiovascular disease) was 19.1%. The subjects with apoB/apoA-I>0.9 were characterized by higher TG levels and atherogenic index of plasma (AIP) and lower values of ratio of low-density lipoprotein cholesterol (LDL-C) to apoB (LDL-C/apoB) and apoE levels compared with men with apoB/apoA-I<0.9. Conclusion. Despite normolipidemia, the subjects with the unfavorable apoB/apoA-I ratio had more atherogenic lipid profile.

Treatment with omega-3 fatty acid ethyl-ester alters fatty acid composition of lipoproteins in overweight or obese adults with insulin resistance

INTRODUCTION

The effects of dietary fatty acid supplementation on lipoprotein fatty acid composition have rarely been described.

PATIENTS AND METHODS

Sixty-one overweight and obese adults with dyslipidemia and insulin resistance were randomized to placebo, 2g/day extended-release nicotinic acid (ERN), 4g/day prescription omega-3 fatty acid ethyl ester (P-OM3), or combination therapy for 16 weeks. Lipoprotein fatty acid composition was analyzed by gas chromatography pre- and post-treatment.

RESULTS

Treatment with P-OM3 or combination, but not ERN, increased proportions of eicosapentaenoic acid, docosahexaenoic acid, and docosapentaenoic acid, and reduced those for arachidonic acid in all lipoprotein fractions, with greatest impact in the high-density lipoprotein fraction. P-OM3-induced changes in eicosapentaenoic acid within low-density lipoproteins and very low-density lipoproteins were associated with beneficial effects on mean arterial pressure and pulse pressure.

CONCLUSIONS

P-OM3 supplementation, with or without ERN, was associated with differentially altered lipoprotein fatty acid composition and improved blood pressure parameters.

LPL gene variants affect apoC-III response to combination therapy of statins and fenofibric acid in a randomized clinical trial of individuals with mixed dyslipidemia

ApoC-III is a proatherogenic protein associated with elevated triglycerides; its deficiency is associated with reduced atherosclerosis. Mixed dyslipidemia, characterized by elevated triglyceride and apoC-III levels and low HDL cholesterol level, with or without elevated LDL cholesterol, increases cardiovascular disease risk and is commonly treated with combined statin and fibrate therapy. We sought to identify single nucleotide polymorphisms (SNPs) associated with apoC-III level response to combination therapy with statins and fenofibric acid (FA) in individuals with mixed dyslipidemia. Participants (n = 1,250) in a multicenter, randomized, double-blind, active-controlled study examining response to FA alone and in combination with statin were genotyped for candidate SNPs. Multivariate linear regression and two-way ANOVA for percent change in apoC-III level were performed. SNPs in the lipoprotein lipase (LPL) gene region, rs1801177 (P = 4.7 × 10(-8)), rs7016529 (P = 1.2 × 10(-6)), and rs249 (P = 4.1 × 10(-5)), were associated with apoC-III response to combination therapy. A haplotype composed of the minor alleles of these SNPs, with 2% population frequency, was associated with an unexpected apoC-III increase in response to statins and FA. This is the first report to show that genetic variation within the LPL gene region can affect the response of apoC-III levels to combined statin and FA therapy.

Acute metabolic responses to a 24-h ultra-marathon race in male amateur runners

The study was conducted to evaluate the metabolic responses to a 24 h ultra-endurance race in male runners. Paired venous and capillary blood samples from 14 athletes (mean age 43.0 ± 10.8 years, body weight 64.3 ± 7.2 kg, VO(2max) 57.8 ± 6.1 ml kg(-1) min(-1)), taken 3 h before the run, after completing the marathon distance (42.195 km), after 12 h, and at the finish of the race, were analyzed for blood morphology, acid-base balance and electrolytes, lipid profile, interleukin-6 (IL-6), high-sensitivity C-reactive protein (hsCRP), and serum enzyme activities. Mean distance covered during the race was 168.5 ± 23.1 km (range 125.2-218.5 km). Prolonged ultra-endurance exercise triggered immune and inflammatory responses, as evidenced by a twofold increase in total leukocyte count with neutrophils and monocytes as main contributors, nearly 30-fold increase in serum IL-6 and over 20-fold rise in hsCRP. A progressive exponential increase in mean creatine kinase activity up to the level 70-fold higher than the respective pre-race value, a several fold rise in serum activities of aspartate aminotransferase and alanine aminotransferase, and a fairly stable serum γ-glutamyl transferase level, were indicative of muscle, but not of liver damage. With duration of exercise, there was a progressive development of hyperventilation-induced hypocapnic alkalosis, and a marked alteration in substrate utilization towards fat oxidation to maintain blood glucose homeostasis. The results of this study may imply that progressive decline in partial CO(2) pressure (hypocapnia) that develops during prolonged exercise may contribute to increased interleukin-6 production.

Serum lipoprotein (a) levels in patients with first unprovoked venous thromboembolism is not associated with subsequent risk of recurrent VTE

INTRODUCTION

Case-control studies suggest that elevated lipoprotein (a) (Lp(a)) is a risk factor for first venous thromboembolism (VTE). Lp(a) has not been prospectively investigated as a possible risk factor for recurrent VTE in first unprovoked VTE patients. We sought to determine if serum Lp(a) levels in patients with unprovoked VTE who discontinue anticoagulants after 5 to 7 months of therapy predict VTE recurrence in a prospective cohort study.

MATERIALS AND METHODS

Serum Lp(a) measurements were obtained from 510 first unprovoked VTE patients treated for 5 -7 months with anticoagulants in a 12 center study. Patients were subsequently followed for a mean of 16.9 months (SD+/-11.2) for symptomatic VTE recurrence which was independently adjudicated with reference to baseline imaging.

RESULTS

There was no significant association between Lp(a) as a continuous variable and recurrent VTE nor in gender stratified subgroups. No statistically significant differences were observed in the median Lp(a) concentrations between patients who recurred and those who did not recur (median (interquartile range): 0.09 g/L (0.17) versus 0.06 g/L (0.11) respectively; p=0.15). The Lp(a) cut-off point of 0.3g/L was not significantly associated with recurrent VTE for the overall population nor in gender stratified subgroups.

CONCLUSIONS

Elevated serum Lp(a) does not appear to be associated with recurrent VTE in patients with history of first unprovoked VTE and may not play a role in identifying patients with unprovoked VTE at high risk of recurrence. There was no optimal predictive threshold for the overall population or for sex sub-groups and Lp(a)>or=0.3 g/L was not a significant predictor of recurrent VTE.

Atherogenic dyslipidemia and oxidative stress: a new look

Although results from in vitro studies and clinical trials demonstrate strong associations between oxidative stress and cardiovascular risk, to date still no convincing data are available to suggest that treatment with antioxidants might reduce vascular events. Oxidative modifications of low-density lipoproteins (LDL) represent an early stage of atherosclerosis, and small, dense LDL are more susceptible to oxidation than larger, more buoyant particles. Oxidized LDL are independent predictors of subclinical and clinical atherosclerosis. Recent studies suggested that novel therapeutic strategies may take into account the removal of such particles from circulation. Future research is required to explore the potential synergistic impact of markers of oxidative stress and atherogenic dyslipidemia, particularly small dense LDL, on cardiovascular risk.

The therapeutic modulation of atherogenic dyslipidemia and inflammatory markers in the metabolic syndrome: what is the clinical relevance?

The metabolic syndrome consists of a constellation of clinical and biochemical risk factors that cluster together and heighten the risk for atherogenesis, cardiovascular diseases, and diabetes. Established risk cardiovascular factors like hypertension, atherogenic dyslipidaemia, and glucose intolerance occur in the setting of insulin resistance and central adiposity, with genetic and environmental influences modulating the ultimate risk. Chronic insults to the endothelium take its toll in the form of silent as well as clinically evident cardiovascular events. The cellular and vascular accompaniments have shed some light into the underlying pathophysiology. Heightened, low-grade inflammatory processes as well as a continuum of vascular insults ranging from early endothelial derangements to advanced atherosclerosis have been examined. In recent years there has been an explosion of basic and clinical knowledge related to the metabolic syndrome. Although dyslipidaemia is considered a traditional risk component for the syndrome, its qualitative aspects, genetically determined subfractions, and variation in proatherogenic tendency have generated renewed interest and debate. New targets within the dyslipidaemic spectrum that have differing clinical relevance are being evaluated. The effect of heredity, lifestyle changes, pharmacotherapeutic agents, and supplements is being investigated. Further research into the impact of dyslipidemia and inflammation as both pathophysiologic risk factors and objects for targeted therapy in the metabolic syndrome should deepen our understanding and unravel answers to the underlying dynamics in this global epidemic.

Who needs to care about small, dense low-density lipoproteins?

BACKGROUND

Increasing evidence suggest that the 'quality' rather than only the 'quantity' of low-density lipoprotein (LDL) exerts a great influence on the cardiovascular risk. Small, dense LDL seem to be an important predictor of cardiovascular events and progression of coronary artery disease (CAD) and their predominance has been accepted as an emerging cardiovascular risk factor by the National Cholesterol Education Program Adult Treatment Panel III.

DISCUSSION

Some studies showed in past years that small, dense LDL are usually elevated in patients at very high cardiovascular risk, such as those with CAD and type 2 diabetes. More recently elevated levels of these particles have been found in other categories of patients at high cardiovascular risk, such as those with non-coronary forms of atherosclerosis (e.g. with carotid artery disease, aortic abdominal aneurysm and peripheral arterial disease) and metabolic diseases (with polycystic ovary syndrome and growth hormone deficiency); notably, in most of them, the predominance of small, dense LDL characterised their type of dyslipidaemia, alone or in combination with elevated triglycerides and reduced high-density lipoproteins cholesterol concentrations.

CONCLUSIONS

The therapeutical modulation of small, dense LDL have been shown to significantly reduce cardiovascular risk and weight reduction and increased physical activity may constitute first-line therapy. In addition, lipid-lowering drugs are able to favourably alter these particles and fibrates and nicotinic acid seem to be the most effective agents. Promising data are also available with the use of rosuvastatin, the latest statin introduced in the market, and ezetimibe, a cholesterol absorption inhibitor.

Update on the role of the atherogenic lipoprotein phenotype in cardiovascular prevention

Higher plasma triglyceride levels and decreased HDL-cholesterol concentrations are usually accompanied by the presence of small, dense LDL in the so-called lipid triad or ‘atherogenic lipoprotein phenotype’. This phenotype is highly atherogenic and its prevalence may suggest an even higher overall burden of atherosclerotic disease as compared with that associated with hypercholesterolemia. As stated by the National Cholesterol Education Program Adult Treatment Panel III, there is evidence suggesting each component of this lipid triad is individually atherogenic. However, the relative contribution of each component cannot be easily determined. Therefore, it has been suggested to consider the atherogenic lipoprotein phenotype as a whole as a risk factor. This is supported by data from epidemiological studies considering high-risk populations, which showed that the contribution to cardiovascular risk of each individual component cannot be dissected from the sum of all factors. We recently investigated the prevalence of the atherogenic lipoprotein phenotype in different categories of patients at higher cardiovascular risk: with coronary and noncoronary forms of atherosclerosis or metabolic diseases, including Type 2 diabetes, polycystic ovary syndrome and growth hormone deficiency. Subjects with higher triglyceride levels, decreased HDL-cholesterol concentrations and increased levels of small, dense LDL (i.e., subjects with the atherogenic lipoprotein phenotype) are common in coronary and noncoronary forms of atherosclerosis. In the future, it may be possible to measure the presence of small, dense LDL to identify subgroups at higher cardiovascular risk.

The Effects of Niacin on Lipoprotein Subclass Distribution

Dyslipidemia is a heterogeneous metabolic condition; high-density lipoprotein (HDL), low-density lipoprotein (LDL), and very-low-density lipoprotein represent families of lipoprotein particles that differ in size and composition and vary in atherogenicity. Lipoprotein subclasses containing apolipoprotein B promote atherosclerosis, of which the most atherogenic appear to be the small, dense LDL and large very-low-density lipoprotein subclasses, while the large HDL2 subclass, which transports esterified cholesterol from the periphery to the liver, is considered the more cardioprotective. Niacin has long been known to improve concentrations of all major lipids and lipoproteins, but it also has consistently favorable effects on subclass distribution. A MEDLINE search was conducted for clinical studies reporting the effects of niacin on lipoprotein subclasses. The niacin-associated elevations in HDL cholesterol likely stem from differential drug effects on subclasses, producing favorable changes in levels of HDL2 and apolipoprotein A-I. Niacin has more moderate LDL cholesterol-lowering efficacy, but this change is associated with an increase in LDL particle size and a shift from small LDL to the less atherogenic, large LDL subclasses. In addition, it also tends to decrease concentrations of the larger very-low-density lipoprotein subclasses. Niacin confers diverse benefits with respect to both the quantity and quality of lipid and lipoprotein particles.

Small, dense low-density-lipoproteins and the metabolic syndrome

Small, dense low-density-lipoproteins (LDL) are associated with increased risk for cardiovascular diseases and diabetes mellitus and a reduction in LDL size has been reported in patients with coronary and non-coronary forms of atherosclerosis. LDL size has been accepted as an important predictor of cardiovascular events and progression of coronary artery disease as well as an emerging cardiovascular risk factor by the National Cholesterol Education Program Adult Treatment Panel III. Small, dense LDL, with elevated triglyceride levels and low HDL-cholesterol concentrations, constitute the 'atherogenic lipoprotein phenotype (ALP)', a form of atherogenic dyslipidemia that is a feature of type 2 diabetes and the metabolic syndrome. LDL size and subclasses show specific alterations in patients with the metabolic syndrome that probably significantly increase their cardiovascular risk; however, so far it has not been recommended to incorporate LDL size measurements in treatment plans, when hypolipidemic therapies are installed. Patients with type 2 diabetes are at high cardiovascular risk and it is still on debate if the treatment goals may be identical or whether there are distinct groups with different cardiovascular risks and hence with different treatment goals. Measurements beyond traditional lipids, such as measurements on the presence of small, dense LDL in patients with the metabolic syndrome, may help to identify cardiovascular risk subgroups. In addition, it might be possible in the future to individualize hypolipidemic treatments if more than the traditional lipids are taken into account. LDL size measurement may potentially help to assess cardiovascular risk within the metabolic syndrome and adapt the treatment goals thereafter.

Lipid triad or atherogenic lipoprotein phenotype: a role in cardiovascular prevention?

The term "lipid triad" or "atherogenic lipoprotein phenotype" has been introduced to describe a common form of dyslipidemia, characterized by three lipid abnormalities: increased plasma triglyceride levels, decreased HDL-cholesterol concentrations and the presence of small, dense LDL particles. It has been suggested that the clinical importance of the atherogenic lipoprotein phenotype probably exceeds that of LDL-cholesterol, because many more patients with coronary artery disease are found to have this trait than hypercholesterolaemia. There is a body of evidence that therapies effective against plasma HDL-cholesterol and triglycerides are associated with a strong reduction of cardiovascular risk; in addition, hypolipidemic treatment is able to increase LDL particle size and this increment correlates with regression of coronary stenosis. Recently, the Coordinating Committee of the National Cholesterol Education Program suggested that very high-risk patients may benefit from stronger lipid-lowering measures, a category of individuals that includes those with the atherogenic lipoprotein phenotype. Since the therapeutical modulation of each of the three components of the lipid triad is associated with a strong reduction in the risk of cardiovascular events, LDL size measurement may be extended as much as possible to patients at high risk of cardiovascular diseases.

Prognostic value of lipoproteins and their relation to inflammatory markers among patients with coronary artery disease

BACKGROUND

Lipoproteins and their subfractions are associated with the incidence of atherosclerotic diseases. In patients with coronary artery disease (CAD), low serum concentrations of high density lipoprotein (HDL) and high low-density lipoproteins (LDL) are correlated to myocardial infarction and cardiovascular death. There is growing evidence indicating that those lipoprotein factors are related to the inflammatory process in atherogenesis.

METHODS

We investigated in a median follow up of 3.9 years the association of HDL, apolipoprotein A-I (apoA-I), LDL, apolipoprotein B (apoB), and triglycerides with the incidence of a combined endpoint (myocardial infarction and cardiovascular death) and their relation to markers of inflammation in 1298 patients with angiographically documented CAD.

RESULTS

In univariate analysis, serum concentrations of apoA-I were significantly and inversely related to the combined endpoint, whereas serum concentrations of LDL, apoB, and triglycerides were not. HDL was not significantly related to the endpoint in univariate analyses (p=0.057). Multivariate analyses showed that only apoA-I is an independent predictor. ApoA-I (and HDL) was significantly related to markers of inflammation.

CONCLUSION

Serum apoA-I levels were an independent predictor for fatal and non-fatal cardiovascular events in patients with CAD. This may be related to its anti-inflammatory effect.

Sophisticated tests for susceptibility to atherosclerosis: an added value for heart hospitals

Coronary atherosclerosis is the result of multiple complex metabolic disorders acting alone or in combination. Metabolic cardiology has advanced considerably in the past decade and now offers cardiologists a sophisticated approach to treating the underlying cause(s) of coronary artery disease in patients seen in invasive cardiology practices. Disorders which have now been powerfully linked to coronary artery disease include the small low-density lipoprotein trait, impaired reverse cholesterol transport, homocysteinemia, insulin resistance, aspects of inflammation, and infectious burden. These disorders are common and alone, or in combination, are found in over 90% of patients with coronary artery disease. Treatments for these disorders are well elucidated and have been associated with cardiovascular benefit. Incorporation of a sophisticated metabolic atherosclerosis management unit into existing invasive cardiology practices offers the cardiologist and patient many benefits. The cardiologist obtains a powerful tool that complements invasive cardiology, provides patients with access to cutting-edge diagnosis and treatment, and provides a forum that allows incorporation of clinically valid advances in metabolic cardiovascular care in a time frame far shorter than the traditional consensus recommendation approach. Incorporation of such a clinical service is consistent with the recent American College of Cardiology focus on the "CardioTeam."

Planned, ongoing and recently completed clinical trials for atherosclerosis prevention and regression: an update

Recent landmark studies using hydroxy-methyl-glutaryl-Co-enzyme A reductase inhibitors (HMG-CoA reductase inhibitors or statins), specifically, pravastatin and simvastatin, have led to dramatic changes in medical practice. These clinical trials have demonstrated that clinicians can impact coronary morbidity and mortality in primary (pravastatin) and secondary (pravastatin, simvastatin) prevention settings, including post-infarct patients with 'normal' cholesterol levels (pravastatin). The clinical benefit can be seen irrespective of risk factors at baseline and in women, the elderly and diabetics.

Effects of atorvastatin on serum lipids, lipoproteins, and hemostasis

Serum levels of lipids and lipoproteins were examined in individuals with hyperlipidemia treated with atorvastatin or colestimide and in healthy volunteers. Modified low-density lipoprotein (LDL) was measured by its faster electrophoretic mobility and expressed as charge modification frequency (CMF). Serum levels of total cholesterol (t-chol), triglyceride (TG), very low-density lipoprotein (VLDL)-chol, low-density lipoprotein (LDL)-chol, and CMF were significantly higher in hyperlipidemia, but there was no significant difference in serum high-density lipoprotein (HDL)-chol levels between hyperlipidemic and healthy subjects. Treatment with atorvastatin resulted in significant decreases of serum t-chol, TG, and LDL-chol levels but not serum HDL-chol and VLDL-chol. Treatment with colestimide significantly reduced serum t-chol, HDL-chol, and LDL-chol levels but not those of TG and VLDL-chol. CMF was significantly reduced by treatment with atorvastatin but not by colestimide. Atorvastatin significantly reduced plasma levels of thrombomodulin, thrombin antithrombin complex (TAT) and tissue type plasminogen activator-plasminogen activator inhibitor-I complex. Colestimide moderately prolonged activated partial thromboplastin time and reduction of TAT. Based on its actions of lowering modified LDL and improving hemostatic abnormalities, we postulate that atorvastatin might inhibit the onset of ischemic diseases.

Effect of pitavastatin on apolipoprotein A-I production in HepG2 cell

There are few reports describing the mechanism of HDL-elevating action of HMG-CoA reductase inhibitors (statins). As it is considered that the key step of HDL production is the secretion of apolipoprotein A-I (apoA-I), we investigated the effect of statins on apoA-I synthesis and secretion by HepG2 cell to elucidate the mechanism of the action. Each statin induced apoA-I expression (mRNA and protein) dose-dependently: the rank order of the apoA-I induction pitavastatin (3 microM)>simvastatin (10 microM)>atorvastatin (30 microM). The induction of apoA-I by statins disappeared with addition of mevalonate, which indicates that the effect is HMG-CoA reductase inhibition-dependent. Based on HMG-CoA reductase inhibition, pitavastatin-induced apoA-I more efficiently than simvastatin and atorvastatin. Further study revealed that pitavastatin increased ABCA1 mRNA in HMG-CoA reductase-dependent manner and that Rho and Rho kinase inhibitor (C3T and Y27632) increased apoA-I production in the HepG2 cells. These results suggest that pitavastatin efficiently increases apoA-I in the culture medium of HepG2 cells by promoting apoA-I production through inhibition of HMG-CoA reductase and suppression of Rho activity and by protecting apoA-I from catabolism through ABCA1 induction and lipidation of apoA-I.

Apolipoprotein B and apolipoprotein A-I: risk indicators of coronary heart disease and targets for lipid-modifying therapy

Although LDL cholesterol (LDL-C) is associated with an increased risk of coronary heart disease, other lipoproteins and their constituents, apolipoproteins, may play an important role in atherosclerosis. Elevated levels of apolipoprotein (apo) B, a constituent of atherogenic lipoproteins, and reduced levels of apo A-I, a component of anti-atherogenic HDL, are associated with increased cardiac events. Apo B, apo A-I and the apo B/apo A-I ratio have been reported as better predictors of cardiovascular events than LDL-C and they even retain their predictive power in patients receiving lipid-modifying therapy. Measurement of these apolipoproteins could improve cardiovascular risk prediction.

Design, Synthesis, and Biological Evaluation of Thio-Containing Compounds with Serum HDL-Cholesterol-Elevating Properties

A novel series of substituted sulfanyldihydroimidazolones (1) that modulates high-density lipoprotein cholesterol (HDL-C) has been reported to have HDL-elevating properties in several animal models. Concerns about the chemical and metabolic stability of 1 directed us to explore the structure-activity relationship (SAR) of a related series of substituted thiohydantoins (2). Expansion of the scope of the thiohydantoin series led to exploration of compounds in related thio-containing ring systems 3-7 and the N-cyanoguanidine derivative 8. Compounds were tested sequentially in three animal models to assess their HDL-C elevating efficacy and safety profiles. Further evaluation of selected compounds in a dose-response paradigm culminated in the identification of compound 2.39 as a candidate compound for advanced preclinical studies.

Endothelium and the lipid metabolism: the current understanding

The endothelium is a dynamic organ and responds to various physical and humoral conditions. The endothelium secretes several biologically active substances, both vasoconstrictors and vasodilators, which control these processes. Endothelial function is most commonly assessed as the vasodilatory response to stimuli. Several endothelium-dependent agonists have been identified, each of which acts through a membrane receptor. Nitric oxide which is continuously synthesized by the endothelium has a wide range of biological properties that maintain vascular homeostasis. It is a potent vasodilator and inhibitor of platelet aggregation and thus has an important protective role. Endothelial dysfunction in hypercholesterolemic patients is in large part due to a reduced bioavailability of NO. Traditional coronary risk factors, especially hypercholesterolemia, produce endothelial dysfunction even in patients with normal blood vessels. The underlying mechanisms involve a local inflammatory response, release of cytokines and growth factors, activation of oxidation-sensitive mechanisms in the arterial wall, modulation of intracellular signaling pathways, increased oxidation of low-density lipoprotein cholesterol, and quenching of nitric oxide. Clinical studies have shown a significant improvement in endothelial dysfunction following lowering of serum cholesterol levels, infusion of nitric oxide donors like L-arginine and exercise training. Clinical trials are underway examining the role of endothelin-1 receptor antagonists like bosentan in the prevention of graft atherosclerosis.

Hypercholesterolemia and Dyslipidemia: Issues for the Clinician

The current state of the art in the diagnosis and treatment of lipoprotein disorders has progressed beyond the standard "lipid profile," which includes total low-density lipoprotein (LDL), and high-density lipoprotein (HDL) cholesterol, along with fasting triglycerides. Incorporating aspects of the atherogenic lipoprotein profile (ALP) (ALP and LDL subclass distribution), HDL subclass distribution, apolipoprotein E isoforms, lipoprotein (a), homocysteine, and high-sensitivity C-reactive protein provides the clinician with the tools to create a more detailed, accurate, and personalized diagnosis of disorders contributing to coronary artery disease in their patients. Sophisticated laboratory tests are available to clinicians through technology transfer programs as exemplified by the Lawrence Berkeley National Laboratory/Berkeley HeartLab, Berkeley, CA, collaboration and allow clinicians access to research quality laboratory tools. This has significant clinical relevance because the presence of these disorders guides treatment that is specific to the disorder(s). Appropriate treatment has been shown to have significantly greater clinical benefit in patient subgroups exhibiting the disorder the therapy is most likely to correct. A single drug or lifestyle therapy plan is no longer appropriate for all patients. The treatment must match the individual disorder(s).

Niacin treatment of the atherogenic lipid profile and Lp(a) in diabetes

OBJECTIVE

We tested the hypotheses that niacin is effective for the separate treatments of abnormalities of LDL particle size, HDL2 percentage and Lp(a) without potential negative effects on glycated haemoglobin.

RESEARCH DESIGN AND METHODS

The atherogenic lipid profile lipids, such as triglycerides, small, dense LDL cholesterol (LDLc) particle mass, LDL particle size, total HDLc and HDL2 percentage as well as Lp(a), were measured in 42 diabetic patients with abnormalities of LDL particle size, HDL2 percentage and/or Lp(a) levels before and after niacin treatment. LDL particle size and HDL2 were measured using polyacrylamide gradient gel electrophoreses and Lp(a) was measured by enzyme-linked immunoabsorbance assay (ELISA).

RESULTS

After niacin treatment, LDL peak particle diameter increased from 252 +/- 7 A to 263 +/- 7 (p < 0.0001), small, dense LDLc particle mass decreased from 27 +/- 11 mg/dL to 15 +/- 4 (p < 0.0001), total HDLc increased from 39 +/- 7 mg/dL to 51 +/- 11 (p < 0.0001), HDL2 as the percentage of total HDLc mass increased from 29 +/- 8% to 45 +/- 10 (p < 0.0001) and Lp(a) decreased from 43 +/- 17 mg/dL to 25 +/- 10 (p < 0.0001). Mean haemoglobin A1c level was improved during treatment from 7.6 +/- 1.8% to 6.5 +/- 1.0 (p < 0.0001) using increased oral agent and insulin treatment doses in more than 90% of the patients. A total of 21% of the patients were unable to tolerate niacin owing to reversible side-effects, and 14% were unable to adhere to the niacin dosing regimen of three times daily.

CONCLUSIONS

These data indicate that in diabetic patients, niacin (i) is effective for treating diabetic dyslipidaemias associated with both the atherogenic lipid profile and Lp(a); (ii) must be used with modern and aggressive oral hypoglycaemic agents or insulin treatment; and (iii) is an important drug to treat diabetes dyslipidaemias because of its broad spectrum of effectiveness.

Peroxisome proliferator-activated receptor agonists, hyperlipidaemia, and atherosclerosis

Dyslipidaemia is a major risk factor in the development of atherosclerosis, and lipid lowering is achieved clinically using fibrate drugs and statins. Fibrate drugs are ligands for the fatty acid receptor peroxisome proliferator-activated receptor (PPAR)alpha, and the lipid-lowering effects of this class of drugs are mediated by the control of lipid metabolism, as directed by PPARalpha. PPARalpha ligands also mediate potentially protective changes in the expression of several proteins that are not involved in lipid metabolism, but are implicated in the pathogenesis of heart disease. Clinical studies with bezafibrate and gemfibrozil support the hypothesis that these drugs may have a significant protective effect against cardiovascular disease. The thiazolidinedione group of insulin-sensitising drugs are PPARgamma ligands, and these have beneficial effects on serum lipids in diabetic patients and have also been shown to inhibit the progression of atherosclerosis in animal models. However, their efficacy in the prevention of cardiovascular-associated mortality has yet to be determined. Recent studies have found that PPARdelta is also a regulator of serum lipids. However, there are currently no drugs in clinical use that selectively activate this receptor. It is clear that all three forms of PPARs have mechanistically different modes of lipid lowering and that drugs currently available have not been optimised on the basis of PPAR biology. A new generation of rationally designed PPAR ligands may provide substantially improved drugs for the prevention of cardiovascular disease.

The plasma parameter log (TG/HDL-C) as an atherogenic index: correlation with lipoprotein particle size and esterification rate in apoB-lipoprotein-depleted plasma (FER(HDL))

OBJECTIVES

To evaluate if logarithm of the ratio of plasma concentration of triglycerides to HDL-cholesterol (Log[TG/HDL-C]) correlates with cholesterol esterification rates in apoB-lipoprotein-depleted plasma (FER(HDL)) and lipoprotein particle size.

DESIGN AND METHODS

We analyzed previous data dealing with the parameters related to the FER(HDL) (an indirect measure of lipoprotein particle size). In a total of 1433 subjects from 35 cohorts with various risk of atherosclerosis (cord plasma, children, healthy men and women, pre- and postmenopausal women, patients with hypertension, type 2 diabetes, dyslipidemia and patients with positive or negative angiography findings) were studied.

RESULTS

The analysis revealed a strong positive correlation (r = 0.803) between FER(HDL) and Log(TG/HDL-C). This parameter, which we propose to call "atherogenic index of plasma" (AIP) directly related to the risk of atherosclerosis in the above cohorts. We also confirmed in a cohort of 35 normal subjects a significant inverse correlation of LDL size with FER(HDL) (r = -0.818) and AIP (r = -0.776).

CONCLUSION

Values of AIP correspond closely to those of FER(HDL) and to lipoprotein particle size and thus could be used as a marker of plasma atherogenicity.

The role of risk factors in the development of atherosclerosis

Our understanding of risk factors for atherogenesis has changed significantly over the last decade. In addition to better grasp of the mechanism of action of the "classic" (causal) risk factors, a number of potentially important new factors has emerged. In this review we briefly summarize the evidence of the relation between atherosclerosis and the currently recognized causal risk factors, namely, age, smoking, LDL cholesterol, HDL cholesterol, hypertension, and diabetes. More emphasis has been put on description of the emerging entities such as atherogenic profile of plasma lipoproteins with discussion of LDL and HDL subclasses, Lp(a), homocysteine, and, last but not least, on the role of infection and inflammation in atherogenesis. Whenever possible, we tried to summarize the relevant lines of evidence such as epidemiological, pathological, genetic, and clinical trial data linking the specific factor with atherosclerosis.

New developments in atherosclerosis imaging: electron beam tomography

Recently published data have greatly expanded the applicability of electron beam tomography (EBT) and electron beam angiography (EBA). The prognostic power of coronary artery calcium scoring for cardiac events and associated obstructive disease far surpasses that of conventional risk factors, and will increasingly be incorporated into risk assessment and treatment guidelines. EBT leads to the identification of treatable, non-low-density lipoprotein metabolic disorders that contribute to plaque formation, and to appropriate selection of stress test candidates. Change in calcium score can be used to assess the efficacy of lipid therapy and will serve as a surrogate marker in drug studies. EBA provides effective, noninvasive visualization of native coronary arteries and bypass grafts.

Metabolic disorders contribute to subclinical coronary atherosclerosis in patients with coronary calcification

This investigation determined the prevalence of low-density lipoprotein (LDL) subclass distribution abnormalities, elevated lipoprotein(a) (Lp(a)), and elevated total plasma homocysteine in asymptomatic subjects with subclinical coronary artery disease determined by electron beam tomography (EBT). Fifty-five percent of subjects were classified as higher risk patients and 45% as lower risk patients, employing the National Cholesterol Education Program (NCEP) lipid criteria. EBT was performed in 296 consecutive asymptomatic subjects, and blood was analyzed for total, LDL, and high-density lipoprotein (HDL) cholesterol, triglycerides, LDL subclass distribution by S(3) gradient gel electrophoresis, Lp(a), and total homocysteine. Disorders of LDL subclass distribution were the most common disorder with 60.6% of the population expressing a distribution in the small regions IIIa + IIIb of >20%; and this was more common in the NCEP higher risk group (LDL cholesterol > or =130 and/or HDL cholesterol <35 mg/dl) (p <0.0004). A Lp(a) value >25 mg/dl was found significantly more often in the NCEP higher (36.9%) compared with lower (14.3%) risk group (p <0.001). None of the laboratory measurements correlated with the calcium score or calcium score percentile rank, with the exception of a weak correlation of mean LDL peak particle diameter and calcium percentile (r = 0.14, p = 0.02). Determination of metabolic disorders in addition to LDL cholesterol and HDL cholesterol increased the diagnostic yield from 55.1%, based on NCEP lipid criteria, to 84.1% with the addition of LDL subclass distribution, Lp(a), and total homocysteine. We conclude that: (1) disorders of LDL subclass distribution and elevated Lp(a) occur frequently in NCEP higher risk patients with subclinical coronary artery disease and are the only identifiable disorders in lower NCEP risk patients; and (2) electron beam tomographic evaluation and determination of LDL subclass distribution and Lp(a) should be considered for incorporation into primary prevention guidelines.

Statin-induced inhibition of the Rho-signaling pathway activates PPARalpha and induces HDL apoA-I

Statins are inhibitors of the rate-limiting enzyme in cholesterol synthesis, 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase. In addition to reducing LDL cholesterol, statin treatment increases the levels of the antiatherogenic HDL and its major apolipoprotein apoA-I. Here, we investigated the molecular mechanisms of apoA-I regulation by statins. Treatment with statins increased apoA-I mRNA levels in human HepG2 hepatoma cells, and this effect was reversed by the addition of mevalonate, implicating HMG-CoA reductase as the relevant target of these drugs. Pretreatment with Actinomycin D abolished the increase of apoA-I mRNA, indicating that statins act at the transcriptional level. Indeed, statins increased the human apoA-I promoter activity in transfected cells, and we have identified a statin response element that coincides with a PPARalpha response element known to confer fibrate responsiveness to this gene. The statin effect could be abolished not only by mevalonate, but also by geranylgeranyl pyrophosphate, whereas inhibition of geranylgeranyl transferase activity or treatment with an inhibitor of the Rho GTP-binding protein family increased PPARalpha activity. Using dominant negative forms of these proteins, we found that Rho A itself mediates this response. Because cotreatment with statins and fibrates activated PPARalpha in a synergistic manner, these observations provide a molecular basis for combination treatment with statins and fibrates in coronary heart disease.

Pro and con: high-density lipoprotein, triglycerides, and other lipid subfractions are the future of lipid management

Risk assessment limited to low-density lipoprotein cholesterol (LDL-C) levels fails to identify a substantial proportion of individuals at risk for coronary artery disease. Data from the Prospective Cardiovascular Münster (PRO-CAM) study indicate that triglyceride levels and high-density lipoprotein cholesterol levels are important determinants of risk irrespective of LDL-C level. Risk is most accurately predicted using an algorithm incorporating multiple risk factors, as shown by the multiple logistic function analysis using the independent risk variables identified on multivariate analysis in PROCAM. It remains unclear what effect statin therapy to decrease LDL-C has in individuals with risk associated with factors other than elevated LDL-C. Such individuals might derive preferential benefit from treatments targeting such risk factors.