Exploiting the vascular protective effects of high-density lipoprotein and its apolipoproteins: an idea whose time for testing is coming, part I

Extended-release niacin/laropiprant: reducing niacin-induced flushing to better realize the benefit of niacin in improving cardiovascular risk factors

Treatment with niacin effectively improves multiple lipid parameters and cardiovascular outcomes. Widespread use of niacin, however, is limited by flushing, which is mediated primarily by prostaglandin D2 (PGD2). Laropiprant is a selective PGD2 receptor 1 (DP1) antagonist that reduces objective measures of niacin-induced flushing symptoms upon initiation of therapy and with more chronic use. Results from early dosing and formulation studies have culminated in the development of a combination extended-release (ER) niacin/laropiprant tablet aimed at providing the beneficial lipid-modifying effects of niacin, while reducing niacin-induced flushing. The improvement in the tolerability of niacin with ER niacin/laropiprant allows niacin dosing to initiate directly at 1 g and rapidly advance to a 2-g target dose. ER niacin/laropiprant generally is tolerated well and represents a new treatment option for dyslipidemia that offers the potential for more patients to receive the lipid-modifying and cardiovascular benefits of niacin.

Prevalence of low HDL cholesterol, and relationship between serum HDL and cardiovascular disease in elderly Spanish population: the PREV-ICTUS study

OBJECTIVE

To assess the prevalence of low serum high-density lipoprotein cholesterol (HDL-C) concentration and the relationship between HDL-C and established cardiovascular disease (CVD) in an elderly Mediterranean population.

METHODS

Analysis of Prevención del Riesgo de Ictus, a population-based study on Spanish subjects aged > or = 60 years. Low HDL-C was defined following the European guidelines for cardiovascular prevention [men: < 40 mg/dl (< 1.0 mmol/l); women: < 46 mg/dl (< 1.2 mmol/l)]. The relationship between low HDL-C or HDL-C concentration (in quintiles) and CVD was assessed through multivariate models that included cardiovascular risk factors, statins and subclinical organ damage.

RESULTS

On 6010 subjects (71.7 years, 53.5% women), low HDL-C was present in 17.5% [95% confidence interval (CI): 16.5-18.5] and was more frequent in women [20.4% (19.0-21.8) vs. 14.1% (12.8-15.4) in men p < 0.001] and in patients with diabetes, CVD or statin therapy. Low HDL-C was independently associated with CVD [adjusted odds ratio (OR): 1.46, 95% CI: 1.22-1.74, p < 0.001]. The prevalence of CVD was higher as HDL-C concentration was lower (chi-square trend < 0.001). Compared with the highest quintile [> 65 mg/dl (> 1.67 mmol/l)], adjusted OR for CVD were 1.39 (1.10-1.76), 1.41 (1.11-1.80), 1.49 (1.18-1.89) and 1.91 (1.52-2.39), respectively for those in the fourth [57-65 mg/dl (1.46-1.67 mmol/l)], third [51-56 mg/dl (1.31-1.45 mmol/l)], second [46-50 mg/dl (1.18-1.30 mmol/l)] and first [< 46 mg/dl (< 1.18 mmol/l)] quintiles of HDL-C. This association was seen in males and females.

CONCLUSIONS

A total of 17.5% of this Spanish population aged > or = 60 years had low HDL-C. We found a strong, independent and inverse association between HDL-C concentrations and established CVD, even at ranges of HDL-C considered as normal.

Wild-type apo A-I and apo A-I(Milano) gene transfer reduce native and transplant arteriosclerosis to a similar extent

Apolipoprotein (apo) A-I(Milano) is an apo A-I mutant characterized by a cysteine for arginine substitution at position 173. Apo A-I(Milano) carriers have much less atherosclerosis than expected from their low plasma high-density lipoprotein cholesterol levels, suggesting that this mutant may have superior atheroprotective properties. Here, we compare the effect of hepatocyte-directed gene transfer of wild-type human apo A-I and human apo A-I(Milano) on endothelial progenitor cell (EPC) biology and on the progression of native atherosclerosis and allograft vasculopathy in C57BL/6 apo E(-/-) mice. Human apo A-I and apo A-I(Milano) transfer resulted in an equivalent increase of EPC number and function as well as EPC incorporation and endothelial regeneration in allografts and inhibited the progression of native atherosclerosis and allograft vasculopathy to a similar extent. In conclusion, the current head-to-head comparison indicates that human apo A-I(Milano) transfer is not superior compared to wild-type human apo A-I transfer.

Hypolipidemic and hepatoprotective effects of flax and pumpkin seed mixture rich in omega-3 and omega-6 fatty acids in hypercholesterolemic rats

Flax and pumpkin seeds are a rich source of unsaturated fatty acids, antioxidants and fibers, known to have anti-atherogenic and hepatoprotective activities. These effects were evaluated in Wistar rats fed with 1% cholesterol diet. The study was performed on 30 male rats divided into three groups: a control group (CD), CD-chol group fed diet with 1% cholesterol and MS-chol group fed diet enriched with flax and pumpkin seed mixture. In CD-chol group, total cholesterol TC, triacylglycerol TG in plasma and liver, plasma LDL-C, atherogenic index AI and LDL/HDL ratio significantly increased. In MS-chol group lipid parameters decreased significantly, plasma and liver fatty acid composition showed an increase of PUFAs (ALA and LA), and MUFAs (oleic and eicosaenoic acid) and a decrease of SFA (palmitic and stearic acid). In plasma and liver of MS-chol group, malondialdehyde levels decreased and the efficiency of antioxidant defense system was improved compared to CD-chol group. Liver histological sections showed lipid storage in hepatocytes of CD-chol group and an improvement was noted in MS-chol group. Our results suggested that flax and pumpkin seed mixture had anti-atherogenic and hepatoprotective effects which were probably mediated by unsaturated fatty acids present in seed mixture.

Emerging HDL-based therapies for atherothrombotic vascular disease

Statin therapy has been a significant advance in the management of dyslipidemia and atherothrombotic cardiovascular disease with a resultant 30% to 40% reduction in cardiovascular events; however, a significant number of events continue to occur in statin-treated patients, including in patients treated with high-dose statins targeted to achieve mean low-density lipoprotein cholesterol levels in the range of 60 to 80 mg/dL. Therefore, development and testing of new therapies that exploit the vascular protective effects of high-density lipoprotein (HDL) constitutes a rational and complementary approach. A number of HDL-based therapies are in various stages of development and testing. It is hoped that one or more of these new HDL-based therapies, if proven effective and safe, will become a part of our armamentarium against vaso-occlusive cardiovascular disease. A paradigm could emerge in which patients recovering from acute coronary syndromes and at high risk of recurrent events could be treated with rapid-acting HDL-based therapy, such as infusions of recombinant HDL or even HDL delipidation, followed by more sustained long-term HDL-based therapies, such as oral agents and perhaps even HDL-based gene therapy.

Serum lipid profiles and their relationship to cardiovascular disease in the elderly: the PREV-ICTUS study

OBJECTIVE

To assess the relationship between different serum lipid profiles and the prevalence of established cardiovascular disease (CVD) in an elderly population.

RESEARCH DESIGN AND METHODS

An analysis was undertaken of the PREV-ICTUS population-based study on Spanish subjects aged > or =60 years. The following definitions were used: abnormal LDL cholesterol (LDL-C): > or =130 mg/dl (> or =3.3 mmol/L), or > or =100 mg/dl (> or =2.5 mmol/L) in those with diabetes or CVD, or treatment with any hypolipidaemic drug; low HDL cholesterol (HDL-C): <40 mg/dl (<1 mmol/L) (men), or <50 mg/dl (<1.3 mmol/L) (women), and abnormal triglycerides (TG): > or =150 mg/dl (> or =1.7 mmol/L) or treatment with fibrates. We defined eight groups: A (normal lipid profile), B (isolated abnormal LDL-C), C (isolated abnormal TG), D (isolated low HDL-C), E (abnormal LDL-C and HDL-C), F (abnormal LDL-C and TG), G (abnormal TG and HDL-C), H (abnormal LDL-C, HDL-C and TG). A multivariate analysis was performed to assess the relationship between each lipid profile and CVD.

RESULTS

A total of 6010 subjects (mean age 71.7 years, 53.5% women, 73.2% with hypertension, 29.2% with diabetes mellitus, 24.3% with CVD), were included in the analysis. LDL-C elevation was present in 78.1%, 23.3% had low HDL-C and 35.7% abnormal TG. Combined dyslipidaemias were frequent (40.3%). Odds ratios (95% confidence intervals) for CVD, compared with those with a normal lipid profile, were 2.07 (1.24-3.46) for abnormal HDL-C (p = 0.005), 4.09 (3.10-5.39) for abnormal LDL-C; 6.41 (4.59-8.95) for abnormal LDL-C plus HDL-C, 5.33 (3.98-7.14) for abnormal LDL-C plus TG and 7.59 (5.51-10.5) for those with the three parameters altered (all p < 0.001). Compared with those with isolated LDL-C elevation, those with abnormal LDL-C plus HDL-C had 1.57 (1.30-1.97) higher odds of having CVD (p < 0.001), the figures being 1.30 (1.11-1.53) for those with abnormal LDL-C plus TG and 1.86 (1.52-2.28) for those with abnormal LDL-C, TG plus HDL-C (p < 0.001).

CONCLUSIONS

Lipid abnormalities are frequent in the elderly, and are associated with the presence of CVD. Low HDL-C and/or abnormal TG levels, when added to abnormal LDL-C, are associated with a higher prevalence of CVD, suggesting the advisability of a comprehensive lipid evaluation and treatment earlier in life.

Apolipoprotein A-I versus HDL cholesterol in the prediction of risk for myocardial infarction and stroke

PURPOSE OF REVIEW

To compare the potential of high-density lipoprotein (HDL) cholesterol and apolipoprotein (apo) A-I, the major protein in HDL particles, in predicting cardiovascular risk. Pros and cons for using these risk markers are discussed.

RECENT FINDINGS

Both HDL cholesterol and apoA-I are in most clinical conditions antiatherogenic - the higher the values, the lower the cardiovascular risk. Methodological and physiological factors speak in favour of using apoA-I rather than HDL cholesterol as a marker of risk. In prospective risk studies and in lipid-lowering trials it has been shown that the apoB/A-I ratio, which reflects the cholesterol balance between all potentially atherogenic (apoB) and antiatherogenic lipoproteins (apoA-I), is a better risk marker than low-density lipoprotein cholesterol, HDL cholesterol and lipid ratios in predicting cardiovascular risk and response to lipid lowering induced by statins. Practical advantages speak in favour of using apoB and apoA-I - fasting is not needed to analyze and interpret the values of apoB and apoA-I.

SUMMARY

New guidelines should be developed in which target values for apoB and apoA-I are defined to enable the use of these new strong risk markers/factors in clinical practice.

Lipoprotein predictors of cardiovascular events in statin-treated patients with coronary heart disease. Insights from the Incremental Decrease In End-points Through Aggressive Lipid-lowering Trial (IDEAL)

BACKGROUND

Few studies have looked into the ability of measurements of apolipoprotein B (apoB) and apolipoprotein A-1 (apoA-1) or apoB/apoA-1 to predict new coronary heart disease (CHD) events in patients with CHD on statin treatment.

AIMS

In the IDEAL trial, to compare lipoprotein components to predict CHD events and to what degree differences in those parameters could explain the observed outcome.

METHODS

We compared the ability of treatment with atorvastatin 80 mg/day to that of simvastatin 20-40 mg/day to prevent CHD events in patients with CHD and used Cox regression models to study the relationships between on-treatment levels of lipoprotein components to subsequent major coronary events (MCE).

FINDINGS

Variables related to low-density lipoprotein cholesterol (LDL-C) carried more predictive information than those related to high-density lipoprotein cholesterol (HDL-C), but LDL-C was less predictive than both non-HDL-C and apoB. The ratio of apoB to apoA-1 was most strongly related to MCE. However, for estimating differences in relative risk reduction between the treatment groups, apoB and non-HDL-C were the strongest predictors.

INTERPRETATION

The on-treatment level of apoB/apoA-1 was the strongest predictor of MCE in the pooled patient population, whereas apoB and non-HDL-C were best able to explain the difference in outcome between treatment groups. Measurements of apoB and apoA-1 should be more widely available for routine clinical assessments.

Differential regulation of apolipoprotein A-I gene expression by vitamin D receptor modulators

We have found that 1,25-dihydroxy-cholecalciferol (1,25-(OH)(2)D(3)) represses the expression of the apolipoprotein A-I (apo A-I) gene in hepatocytes. In this manuscript we examined the effects of the vitamin D receptor (VDR) modulators EB1089 (EB) and ZK191784 (ZK) on expression of the apo A-I gene in liver (HepG2) and in intestinal (Caco-2) cells. In HepG2 cells, EB and ZK induced apo A-I secretion and gene promoter activity in a dose-dependent manner. This induction did not require the VDR since antisense-mediated inhibition of VDR had no appreciable effect on apo A-I promoter activity in cells treated with EB or ZK. Although repression of apo A-I gene expression by 1,25-(OH)(2)D(3) in hepatocytes required nuclear receptor binding to site A in the promoter, this cis-element was insufficient for induction of apo-AI by EB and ZK. In Caco-2 cells, treatment with 1,25-(OH)(2)D(3) had no effect on apo A-I protein secretion or promoter activity while EB induced and ZK inhibited apo A-I gene expression. Gel shift assays showed that none of the treatments resulted in a change in site A binding activity. These results indicate that VDR modulators in hepatocytes and intestinal cells differentially regulate expression of the apo A-I gene.

High-density lipoprotein cholesterol and residual cardiometabolic risk in metabolic syndrome

It has long been recognized that elevated levels of low-density lipoprotein cholesterol (LDL-C) increase the risk of cardiovascular disease (CVD) and that pharmacologic therapy to decrease LDL-C significantly reduces cardiovascular events. Despite the effectiveness of statins for CVD risk reduction, even optimal LDL-lowering therapy alone fails to avert approximately 60% to 70% of CVD cases, and the incidence of CVD mortality continues to grow. A low plasma concentration of high-density lipoprotein cholesterol (HDL-C) is also associated with increased risk of CVD and is 1 component of metabolic syndrome, a cluster of interrelated CVD risk factors. HDL stimulates reverse cholesterol transport from the peripheral tissues to the liver for removal from the body, prevents deleterious effects of LDL on endothelial function, acts as an antioxidant, and also possesses anti-inflammatory, antithrombotic, and antiapoptotic effects. Some of the treatments that increase HDL-C concentrations have been shown to reduce atheroma volume and may prevent the formation of new atherosclerotic lesions, thereby reducing the risk of CVD. For these reasons, increasing HDL-C concentrations has become a potentially attractive therapeutic target for individuals who are at increased risk of CVD, including those with metabolic syndrome. Traditional strategies to increase HDL-C include the use of niacin, statins, and fibric acid derivatives. Pharmacotherapies that have recently been developed and are currently being evaluated include inhibition of the enzyme cholesteryl ester transfer protein (CETP) and antagonism of the endocannabinoid CB1 receptor. Initial studies of CETP inhibitors suggest that these agents may markedly increase HDL-C concentrations. Clinical trials with rimonabant, a CB1 receptor antagonist, have demonstrated significant weight loss as well as increased HDL-C levels and reduced triglyceride levels.

Anti-atherogenic effects of seabuckthorn (Hippophaea rhamnoides) seed oil

Seabuckthorn (SBT) seed oil is a rich source of unsaturated fatty acids, phytosterols, carotenoids and flavonoids, which are known to have significant anti-atherogenic and cardioprotective activity. The anti-atherogenic activity of supercritical CO(2) extracted SBT seed oil was evaluated in white albino rabbits fed on high cholesterol diet for 60 days. The study was performed on 20 male healthy rabbits divided into four groups of 5 animals each. Group I - control, group II - SBT seed oil, group III - cholesterol (1%) for 60 days, group IV - cholesterol+SBT seed oil. After 30 days of high cholesterol diet, group IV rabbits received 1 ml of SBT seed oil daily for 30 days. Blood total cholesterol (TC), LDL-cholesterol (LDL-C), HDL-cholesterol (HDL-C) and triglyceride (TG) levels were measured before and after the administration of SBT seed oil. The vasorelaxant activity of the seed oil was studied in vitro using aortic ring model technique and changes in isometric force were recorded using a polygraphic recording system. Accumulation of cholesterol in the aorta was studied using Sudan-IV staining technique. SBT seed oil feeding to normal rabbits for 18 days caused a significant decline in plasma cholesterol, LDL-C, atherogenic index (AI) and LDL/HDL ratio. The HDL-C levels, HDL-C/TC ratio (HTR) and vasorelaxant activity of the aorta were significantly increased. In cholesterol-fed animals the TC, TG, LDL-C and AI were significantly increased and showed a decline following seed oil administration. The increase in HDL-C was more marked in seed oil treated hypercholesterolemic animals. The acetylcholine-induced vasorelaxant activity was significantly decreased in cholesterol-fed animals and could be restored to that of normal values by seed oil administration. These observations suggest that supercritical CO(2) extracted SBT seed oil has significant anti-atherogenic and cardioprotective activity.

Immunization for atherosclerosis

This review summarizes experimental findings that highlight the complex roles of the immune system in atherogenesis. Immune activation can have either proatherogenic or atheroprotective effects. Immune-modulation therapy via an active or passive immunization strategy aims to exploit the atheroprotective aspects of the immune system to modulate atherosclerosis. Several experimental studies have demonstrated that such an approach is feasible and effective, raising the tantalizing possibility that an atheroprotective vaccine can be developed for clinical testing. Several potential immunogens have been identified and tested for their atheroprotective efficacy with variable results. Although several questions such as choice of optimal antigens, choice of most effective adjuvants, the optimal route of administration, durability of effects, and safety remain to be answered, we believe that a vaccine-based approach to manage atherosclerotic cardiovascular disease is a potentially viable paradigm.

Role of High-Density Lipoprotein and Scavenger Receptor B Type I in the Promotion of Endothelial Repair

There is considerable experimental evidence that high-density lipoprotein (HDL) cholesterol and the principal high-affinity HDL receptor scavenger receptor B type I (SR-BI) afford cardiovascular protection. However, the fundamental mechanisms underlying the protection remain complex and not well understood. Recent work in cell culture indicates that the HDL-SR-BI tandem stimulates endothelial cell migration. Further studies have revealed that this entails Src-mediated, phosphatidylinositol 3-kinase-mediated, and mitogen-activated protein kinase-mediated signaling that leads to the activation of Rac guanosine triphosphate hydrolase and the resultant rearrangement of the actin cytoskeleton. Furthermore, assessment of reendothelialization after perivascular electric injury in mice indicates that HDL-SR-BI-mediated stimulation of endothelial migration is operative in vivo. Recent additional work in mice also indicates that HDL activates the recruitment of endothelial progenitor cells into the intimal layer in the setting of endothelial injury. As such, signaling initiated by HDL-SR-BI promotes endothelial repair, and this novel mechanism of action may be critically involved in the impact of the lipoprotein on vascular health and disease.

Efetividade de um programa de exercícios no condicionamento físico, perfil metabólico e pressão arterial de pacientes hipertensos

HISTÓRICO E OBJETIVO: Tem sido mostrado que exercícios aeróbios são úteis na redução da pressão arterial. Contudo, a efetividade de um programa de exercícios ainda é controversa e não foi bem analisada em populações de baixa renda. O objetivo do presente estudo foi estabelecer um programa de condicionamento físico individualizado - Projeto Hipertensão - focado em pessoas hipertensas, pacientes da Unidade Básica de Saúde (UBS) e, logo após, investigar os efeitos deste programa no condicionamento físico, perfil metabólico e níveis de pressão. MÉTODOS: Dezesseis mulheres hipertensas (56 ± 3 anos) sob tratamento farmacológico regular foram submetidas a 4 meses de um programa de exercícios aeróbios e de alongamento (3 sessões/semana, 90 min/sessão, 60% de VO2max.) Diversas variáveis físicas e metabólicas foram comparadas antes e depois de 4 meses de treinamento. RESULTADOS: O treinamento diminuiu significativamente a pressão arterial sistólica (PAS, -6%); melhorou o condicionamento cardiorrespiratório (+42% do VO2max), flexibilidade (+11%) e conteúdo de glicose plasmática (-4%). IMC e % de gordura não tiveram modificação. Além de modificar o perfil metabólico, observou-se que o treinamento apresentou correlações significativas entre os valores iniciais individuais de nível de colesterol total (CT), lipoproteína de alta densidade (HDL-C) e lipoproteína de baixa densidade (LDL-C) e suas respostas após exercício. CONCLUSÕES: O estudo mostra que programas de exercício podem ser personalizados para pacientes hipertensos da UBS e confirma a efetividade do exercício na PA, condicionamento físico, flexibilidade e perfil lipídico em pacientes hipertensos. A redução expressiva de PA em sujeitos hipertensos sugere que esta intervenção de exercícios deve ser enfatizada em outros centros que assistam populações de baixa renda.

Effect of torcetrapib on the progression of coronary atherosclerosis

BACKGROUND

Levels of high-density lipoprotein (HDL) cholesterol are inversely related to cardiovascular risk. Torcetrapib, a cholesteryl ester transfer protein (CETP) inhibitor, increases HDL cholesterol levels, but the functional effects associated with this mechanism remain uncertain.

METHODS

A total of 1188 patients with coronary disease underwent intravascular ultrasonography. After treatment with atorvastatin to reduce levels of low-density lipoprotein (LDL) cholesterol to less than 100 mg per deciliter (2.59 mmol per liter), patients were randomly assigned to receive either atorvastatin monotherapy or atorvastatin plus 60 mg of torcetrapib daily. After 24 months, disease progression was measured by repeated intravascular ultrasonography in 910 patients (77%).

RESULTS

After 24 months, as compared with atorvastatin monotherapy, the effect of torcetrapib-atorvastatin therapy was an approximate 61% relative increase in HDL cholesterol and a 20% relative decrease in LDL cholesterol, reaching a ratio of LDL cholesterol to HDL cholesterol of less than 1.0. Torcetrapib was also associated with an increase in systolic blood pressure of 4.6 mm Hg. The percent atheroma volume (the primary efficacy measure) increased by 0.19% in the atorvastatin-only group and by 0.12% in the torcetrapib-atorvastatin group (P=0.72). A secondary measure, the change in normalized atheroma volume, showed a small favorable effect for torcetrapib (P=0.02), but there was no significant difference in the change in atheroma volume for the most diseased vessel segment.

CONCLUSIONS

The CETP inhibitor torcetrapib was associated with a substantial increase in HDL cholesterol and decrease in LDL cholesterol. It was also associated with an increase in blood pressure, and there was no significant decrease in the progression of coronary atherosclerosis. The lack of efficacy may be related to the mechanism of action of this drug class or to molecule-specific adverse effects. (ClinicalTrials.gov number, NCT00134173 [ClinicalTrials.gov].).

High-Density Lipoprotein Cholesterol: A Potential Therapeutic Target for Prevention of Coronary Artery Disease

High-density lipoprotein cholesterol has an important role in the pathophysiology of coronary artery disease. High-density lipoprotein cholesterol is becoming an increasingly important prognostic and therapeutic target. The purpose of this paper is to review the biochemical pathways involved in reverse cholesterol transport and to discuss potential, clinically based high-density lipoprotein therapies that may contribute to reduction in risk of atherosclerosis.

Will torcetrapib be the next big thing in coronary heart disease risk reduction?

Scientists are seeking ways to increase high-density lipoprotein (HDL) cholesterol to lower coronary heart disease (CHD). Emerging from this search is torcetrapib, a partial inhibitor of cholesteryl ester transfer protein. Via this mechanism, cholesteryl ester is prevented from being transferred to apolipoprotein B-containing lipoproteins and is retained in HDL particles, where ostensibly it may be delivered directly to the liver for elimination. Proof that this may reduce atherosclerotic vascular disease is provided by population studies of cholesteryl ester transfer protein (CETP) deficiencies and single nucleotide polymorphisms of CETP, and experiments in animal models treated with torcetrapib. Torcetrapib effectively raises HDL cholesterol when used alone and when added to background therapy with atorvastatin. The drug appears to be well tolerated. Large surrogate and survival outcome trials are underway to document its impact on CHD.

Emerging strategies for increasing high-density lipoprotein

High-density lipoprotein cholesterol is a potent and independent epidemiologic risk factor and is a proved antiatherosclerotic agent in animal models of atherosclerosis, acting through the principal mechanisms of accelerating cholesterol efflux and inhibiting oxidation and inflammation. Lifestyle modification increases serum levels by 5% to 15%, whereas niacin, the drug most widely used to increase high-density lipoprotein cholesterol, increases it by 25% to 35% at the highest doses. This review examines the potent methods of increasing high-density lipoprotein and/or enhancing reverse cholesterol transport, including cholesterol ester transfer protein inhibitors, apolipoprotein A-I Milano, D4F, the dual peroxisome proliferator-activated receptor agonists, and rimonabant, that are now in clinical trials. In conclusion, these new agents, used alone or in combination with existing therapies, carry the potential to markedly reduce the incidence of new coronary disease and cardiac events in this decade.

A long and winding road: defining the biological role and clinical importance of paraoxonases

Paraoxonase-1 (PON1) is an enzyme belonging to a three-member gene family, each of which is highly conserved in mammalian evolution. Whilst there is consensus that the paraoxonase family members have a general protective influence, their precise biological role has remained elusive. A toxicological role, protecting from environmental poisoning by organophosphate derivatives, drove much of the earlier work on the enzymes. More recently, clinical interest has focused on a protective role in vascular disease via a hypothesised impact on lipoprotein lipid oxidation. Recent confirmation that the primary activity of the paraoxonases is that of a lactonase considerably expands the potential sources of biological substrates for the enzyme. Studies on such substrates may shed further light on different mechanisms by which paraoxonases beneficially influence atherosclerosis, as well as defining possible roles in limiting bacterial infection and in innate immunity.

Association of high-density lipoprotein levels and carotid atherosclerotic plaque characteristics by magnetic resonance imaging

A low level of high-density lipoprotein cholesterol (HDL-C) is a risk factor for atherosclerotic disease. Magnetic resonance imaging (MRI) can provide detailed information on carotid atherosclerotic plaque size and composition. The purpose of this study was to correlate HDL levels with carotid plaque burden and composition by MRI. Thirty-four patients with coronary artery disease (CAD) receiving simvastatin plus niacin or placebo for both drugs for three years were randomly selected to undergo MRI of carotid arteries. Atherosclerotic plaque wall volumes (WVs) and plaque components including lipid rich/necrotic core (LR/NC), calcium, fibrous tissue, and loose matrix were measured. Mean WV or atherosclerotic burden was significantly associated with total HDL-C levels (r = -0.39, P = 0.02), HDL(2) (r = -0.36, P = 0.03), HDL(3) (r = -0.34, P = 0.04), and LDL/HDL ratio (r = 0.42, P = 0.02). Plaque lipid composition or LR/NC was significantly associated with HDL(3) (r = -0.68, P = 0.02). Patients with low HDL levels (<or=35 mg/dL) had increased WV (97 +/- 23 vs. 81 +/- 19 mm(3), P = 0.05) compared with patients with HDL levels > 35 mg/dL. Among CAD patients, low HDL-C levels were significantly associated with increased carotid atherosclerotic plaque burden and lipid content by MRI.

Antioxidant and cytoprotective properties of high-density lipoproteins in vascular cells

Beside their key role in the regulation of cholesterol homeostasis, HDL exhibit antioxidant and anti-inflammatory properties that participate to their general antiatherogenic effect. The purpose of this review is to summarize the recent findings on antioxidant activity and cytoprotective cell signalling elicited by HDL against oxidized LDL and proatherogenic agents in vascular cells. HDL exhibit an antioxidant activity efficient to prevent LDL oxidation, or to inactivate newly formed lipid oxidation products. The antioxidant ability of HDL is due to the apoprotein moiety and to the presence of associated enzymes, paraoxonase and PAF-Acetyl Hydrolase. HDL prevent the intracellular oxidative stress and the inflammatory response elicited by oxidized LDL (ox-LDL), by inhibiting the NFkappaB signalling pathway, and the subsequent inflammatory events (expression of adhesion molecules, recruitment and proliferation of mononuclear cells within the vascular wall). HDL prevent ox-LDL-mediated cell activation and proliferation, this being also attributed to the presence in HDL of sphingosine-1 phosphate which modulates the migration and survival of vascular cells. Lastly, HDL inhibit apoptosis elicited by ox-LDL in vascular cells. Recent evidences indicate that, beside their strong antiatherogenic properties, HDL could exert their protective effect in diseases generally associated to inflammatory events.

The apoB/apoA-I ratio: a strong, new risk factor for cardiovascular disease and a target for lipid-lowering therapy--a review of the evidence

During the last several years interest has focused on the importance of the lipid-transporting apolipoproteins--apoB transports all potentially atherogenic very low-density lipoprotein (VLDL), intermediate-density lipoprotein (IDL) and LDL particles, and apoA-I transports and acts as the major antiatherogenic protein in the HDL particles. The evidence for the apoB/apoA-I ratio being a strong, new risk factor for cardiovascular (CV) disease and a target for lipid-lowering therapy is reviewed. Results from clinical prospective studies and lipid-lowering trials in healthy subjects and in patients with different clinical manifestations of atherosclerosis are reported. Risk of nonfatal and fatal myocardial infarction and stroke, and manifestations of atherosclerosis documented by angiographic, ultrasound and other techniques has been related to conventional lipids and apolipoproteins (apo). The cholesterol balance determined as the apoB/apoA-I ratio has repeatedly been shown to be a better marker than lipids, lipoproteins and lipid ratios. The results indicate that the apoB/apoA-I ratio is a simple, accurate and new risk factor for CV disease--the lower the apoB/apoA-I ratio, the lower is the risk. Guidelines should be developed in order to recognize the important clinical risk information embedded in the apoB/apoA-I ratio.

Endothelial dysfunction: a comprehensive appraisal

The endothelium is a thin monocelular layer that covers all the inner surface of the blood vessels, separating the circulating blood from the tissues. It is not an inactive organ, quite the opposite. It works as a receptor-efector organ and responds to each physical or chemical stimulus with the release of the correct substance with which it may maintain vasomotor balance and vascular-tissue homeostasis. It has the property of producing, independently, both agonistic and antagonistic substances that help to keep homeostasis and its function is not only autocrine, but also paracrine and endocrine. In this way it modulates the vascular smooth muscle cells producing relaxation or contraction, and therefore vasodilatation or vasoconstriction. The endothelium regulating homeostasis by controlling the production of prothrombotic and antithrombotic components, and fibrynolitics and antifibrynolitics. Also intervenes in cell proliferation and migration, in leukocyte adhesion and activation and in immunological and inflammatory processes. Cardiovascular risk factors cause oxidative stress that alters the endothelial cells capacity and leads to the so called endothelial "dysfunction" reducing its capacity to maintain homeostasis and leads to the development of pathological inflammatory processes and vascular disease.

There are different techniques to evaluate the endothelium functional capacity, that depend on the amount of NO produced and the vasodilatation effect. The percentage of vasodilatation with respect to the basal value represents the endothelial functional capacity. Taking into account that shear stress is one of the most important stimulants for the synthesis and release of NO, the non-invasive technique most often used is the transient flow-modulate "endothelium-dependent" post-ischemic vasodilatation, performed on conductance arteries such as the brachial, radial or femoral arteries. This vasodilatation is compared with the vasodilatation produced by drugs that are NO donors, such as nitroglycerine, called "endothelium independent". The vasodilatation is quantified by measuring the arterial diameter with high resolution ultrasonography. Laser-Doppler techniques are now starting to be used that also consider tissue perfusion.

There is so much proof about endothelial dysfunction that it is reasonable to believe that there is diagnostic and prognostic value in its evaluation for the late outcome. There is no doubt that endothelial dysfunction contributes to the initiation and progression of atherosclerotic disease and could be considered an independent vascular risk factor. Although prolonged randomized clinical trials are needed for unequivocal evidence, the data already obtained allows the methods of evaluation of endothelial dysfunction to be considered useful in clinical practice and have overcome the experimental step, being non-invasive increases its value making it use full for follow-up of the progression of the disease and the effects of different treatments.

The effect of select nutrients on serum high-density lipoprotein cholesterol and apolipoprotein A-I levels

One of the factors contributing to the increased risk of developing premature atherosclerosis is low plasma concentrations of high-density lipoprotein (HDL) cholesterol (HDLc). Multiple potential mechanisms account for the cardioprotective effects of HDL and its main protein apolipoprotein A-I (apo A-I). The low plasma concentrations of HDL could be the result of increased fractional clearance and reduced expression of apo A-I. To this end, nutrients play an important role in modulating the fractional clearance rate, as well as the rate of apo A-I gene expression. Because medical nutrition therapy constitutes the cornerstone of management of dyslipidemias, it is essential to understand the mechanisms underlying the changes in HDL level in response to alterations in dietary intake. In this review, we will discuss the effect of select nutrients on serum HDLc and apo A-I levels. Specifically, we will review the literature on the effect of carbohydrates, fatty acids, and ketones, as well as some of the nutrient-related metabolites, such as glucosamine and the prostanoids, on apo A-I gene expression. Because there are multiple mechanisms involved in the regulation of serum HDLc levels, changes in gene transcription do not necessarily correlate with clinical observations on serum levels of HDLc.

Endocrinology and Dialysis Jean L. HolleySeries Editor: Lipid Abnormalities Associated with End-Stage Renal Disease

Patients undergoing chronic renal replacement therapy have a high incidence of dyslipidemia. In general, there are increased concentrations of triglyceride-rich apolipoprotein B-containing particles. These elevations lead to increased levels of non-high-density lipoprotein (HDL) levels. This pattern is further modified by the method of dialysis (peritoneal versus hemodialysis) and comorbidities such as diabetes. End-stage renal disease patients also demonstrate increased levels of lipoprotein(a) (Lp(a)) and oxidized low-density lipoprotein (LDL)both of which are highly atherogenic. This review focuses on the pathogenesis of these lipid abnormalities and their role in the atherosclerotic process.

Prevalence of Helicobacter pylori infection and its association with cardiovascular risk factors in Korean adults

OBJECTIVE

The purpose of this study is to evaluate the prevalence of Helicobacter pylori (H. pylori) infection and its association with cardiovascular risk factors in healthy Korean adults. In 58981 subjects who participated in health screening program, the proportion of seropositive subjects for H. pylori and its association with cardiovascular risk factors was evaluated.

RESULTS

A total of 70.9% of participants were tested positive for the H. pylori antibody. The seropositivity was highest in the age group of 50 and 60 years old. More male subjects tended to be infected with H. pylori (p<0.05) than female subjects except for the age group of 50s. H. pylori seropositive subjects tended to be older than seronegative subjects (41.5 vs. 39.2 years old). After adjusting for age, H. pylori-seropositive group showed higher mean values for total cholesterol, triglyceride, low-density lipoprotein (LDL)-cholesterol, apolipoprotein B and lower values for high-density lipoprotein (HDL)-cholesterol, apolipoprotein A1 (p<0.05). In univariate correlation analysis, age, total cholesterol, LDL-cholesterol and apolipoprotein B were positively correlated and HDL-cholesterol and apolipoprotein A1 were negatively correlated with H. pylori immunoglobulin G (IgG) titers (p<0.05). The multiple analysis of covariance analysis (MANCOVA) for the H. pylori infection status showed triglyceride, HDL-cholesterol and apolipoproteins associated with H. pylori infection significantly (p<0.05). In the analysis performed only in the H. pylori-seropositive group, no difference between the groups with and without peptic ulcer were shown according to the risk factors except HDL-cholesterol (p=0.031).

CONCLUSIONS

H. pylori infection is prevalent in Korean adults and is associated with cardiovascular risk factors, especially with triglyceride, HDL-cholesterol and apolipoproteins, independently from the presence of peptic ulcer. This is in line with the previous study results in which H. pylori infection per se might be one of the factors affecting atherosclerosis through modulation of lipid profiles, which needs further research.

High-density lipoprotein cholesterol therapies: the next frontier in lipid management

Current cholesterol treatment guidelines target low-density lipoprotein cholesterol as the primary goal of therapy and recommend statins as first line therapy. However, despite aggressive treatment and success at reaching the recommended goals, coronary heart disease is still a leading cause of morbidity and mortality. Thus, other lipoproteins, such as high-density lipoprotein, are now being looked to as the next promising targets of therapy to help reduce the burden of coronary heart disease and atherosclerosis. This review details currently available strategies to raise high-density lipoprotein cholesterol, and then turns to several new compounds in development that target the varying components of the complex metabolism of high-density lipoprotein.

Atherothrombosis and high-risk plaque: part I: evolving concepts

Atherothrombosis is a complex disease in which cholesterol deposition, inflammation, and thrombus formation play a major role. Rupture of high-risk, vulnerable plaques is responsible for coronary thrombosis, the main cause of unstable angina, acute myocardial infarction, and sudden cardiac death. In addition to rupture, plaque erosion may also lead to occlusive thrombosis and acute coronary events. Atherothrombosis can be evaluated according to histologic criteria, most commonly categorized by the American Heart Association (AHA) classification. However, this classification does not include the thin cap fibroatheroma, the most common form of high-risk, vulnerable plaque. Furthermore, the AHA classification does not include plaque erosion. As a result, new classifications have emerged and are reviewed in this article. The disease is asymptomatic during a long period and dramatically changes its course when complicated by thrombosis. This is summarized in five phases, from early lesions to plaque rupture, followed by plaque healing and fibrocalcification. For the early phases, the role of endothelial dysfunction, cholesterol transport, high-density lipoprotein, and proteoglycans are discussed. Furthermore, the innate and adaptive immune response to autoantigens, the Toll-like receptors, and the mechanisms of calcification are carefully analyzed. For the advanced phases, the role of eccentric remodeling, vasa vasorum neovascularization, and mechanisms of plaque rupture are systematically evaluated. In the final thrombosis section, focal and circulating tissue factor associated with apoptotic macrophages and circulatory monocytes is examined, closing the link between inflammation, plaque rupture, and blood thrombogenicity.

Comparison of serum lipid values in patients with coronary artery disease at <50, 50 to 59, 60 to 69, and >70 years of age

We evaluated the relation between lipids and precocity of coronary artery disease (CAD) in the real world as characterized by increasing statin use. The highest mean values of total cholesterol, low-density lipoprotein cholesterol, triglycerides, non-high-density lipoprotein (HDL) cholesterol, and ratio of triglycerides to HDL cholesterol were found when CAD was detected in patients who were <50 years of age (p <0.01 for all); the opposite occurred for HDL cholesterol (p <0.01). Triglycerides and ratio of triglycerides to HDL cholesterol were the most powerful, independent variables related to precocity of CAD.

Inflammatory markers and serum lipids in idiopathic dilated cardiomyopathy

Coronary microcirculation is impaired in idiopathic dilated cardiomyopathy (IDC), possibly because of endothelial dysfunction. High-density lipoproteins (HDLs) have the potential to regulate endothelial function and modulate inflammation and the innate immune response. This study investigated whether reduced HDLs, concomitantly with the activation of inflammation, are associated with IDC. Fifty-five patients with IDC, without evidence of other organ or systemic, chronic, or recurrent diseases, were compared with 55 healthy controls for HDLs and complete lipid profiles, C-reactive protein, C3 and C4 complement fractions, soluble intercellular adhesion molecule-1 and soluble endothelial leukocyte adhesion molecule-1, haptoglobin, and ceruloplasmin. Patients with IDC differed from controls, with lower HDL levels, lower apolipoprotein A-I and A-II levels, and higher triglyceride levels, but not on total and low-density lipoprotein cholesterol, apolipoprotein B, or lipoprotein(a). In addition, all measured inflammation markers were significantly greater in patients with IDC than in controls and were negatively correlated with HDLs. A strong and independent association with IDC was found for age, soluble intercellular adhesion molecule-1, and HDLs that, when categorized as <40 or >40 mg/dl, showed the strongest association (prevalence odds ratio 0.10, p <0.0005) with the disease. In conclusion, the data here reported on reduced HDLs and increased endothelial inflammatory activation and the linear negative correlation between HDLs and inflammation markers, particularly soluble intercellular adhesion molecule-1, could suggest a role for HDLs in the endothelial-microvascular dysfunction seen in IDC.

Apolipoprotein A-I Mimetic Peptides: Potential Role in Atherosclerosis Management

Atherothrombotic vascular disease continues to be a leading cause of morbidity and mortality in much of the world. Although a healthy lifestyle and low-density lipoprotein cholesterol lowering significantly reduce cardiovascular morbidity and mortality, substantial number of adverse vasoocclusive events continue to occur. These realities have brought attention to additional therapies that could further reduce cardiovascular events. High-density lipoprotein (HDL)/apolipoprotein A-I (apo A-I)-based therapies are a potential therapeutic strategy against atherothrombotic vascular disease because of the known inverse relationship between HDL cholesterol and coronary heart disease, favorable and pleotrophic biologic effects of HDL/apo A-I, results of preclinical experimental studies, and emerging proof of concept in clinical studies. A variety of HDL/apo A-I-based therapies are currently under investigation, including synthetic peptides that mimic the function of HDL. Such apo A-I mimetic peptides are the focus of this review.

High-density lipoprotein cholesterol in the cardiovascular equation: does the "good" still count?

This article will discuss our current understanding of the role of HDL-C in the statin era, focusing on the question as to whether HDL-C still "counts" when determining cardiovascular risk. Epidemiologic evidence consistently demonstrates that low HDL-C is a strong and independent risk factor for CHD. The epidemiologic evidence is complimented by clinical data showing that interventions that raise HDL-C are associated with reductions in CHD risk, as well as by a growing body of experimental data demonstrating biologically plausible mechanisms that may underlie the observed clinical findings. Analyses of large statin trials also indicate that the significant and independent relationship between HDL-C and CHD risk persists despite the therapeutic effects of statins, and that HDL-C levels in statin-treated patients, both at baseline and in response to statin therapy, are relevant. Early studies on novel HDL targeting therapies are promising, but their long term safety profile and impact on clinical outcomes is yet to be determined in larger studies. Recent guidelines emphasize low HDL-C as an independent risk factor for cardiovascular disease, specifically identify HDL-C as a target for intervention, and encourage the use of HDL-C raising interventions in high-risk patients with low HDL-C levels.

Variable expressivity of the clinical and biochemical phenotype associated with the apolipoprotein E p.Leu149del mutation

Splenomegaly with sea-blue histiocytes, thrombocytopenia and hypertriglyceridemia is a very rare association that has been described in only one report to date. The molecular defect in the two reported patients consists in a deletion of a leucine at position 149 in the receptor-binding region of the apoE molecule. Here, we report on another family in whom the proband and his brother were diagnosed with splenomegaly, thrombocytopenia and hypertriglyceridemia. An apoE p.Leu149del mutation was found in both subjects. A large beta band in the VLDL fraction and elevated VLDL cholesterol-to-plasma triglyceride ratio was observed in the proband only. Their mother, presenting with isolated hypertriglyceridemia, also carried the same p.Leu149del mutation. The coexistence of factors facilitating the development of hypertriglyceridemia and/or low HDL-cholesterol level could explain why the proband and his brother developed a splenomegaly with thrombocytopenia, whereas the mother did not. Moreover, the presence of an apoE2 allele in the proband likely explains the more severe phenotype we observed in this subject. In conclusion, the apoE p.Leu149del mutation results in a very striking phenotype including one or all symptoms among splenomegaly, thrombocytopenia and hypertriglyceridemia, and should be considered as a differential diagnosis of storage disorders in the causes of splenomegaly with sea-blue histiocytes.

Emerging role of high-density lipoprotein in the prevention of cardiovascular disease

In major statin trials, the relative risk reduction is typically in the range 25-35%, thus indicating that the majority of cardiac events continues to occur despite statin therapy. Hence, there is a considerable interest in identifying novel therapies capable of further reducing cardiovascular disease risk. One such potential therapeutic target is a low level of high-density lipoprotein (HDL) cholesterol. Emerging targets involved in HDL metabolism are: (i) liver X receptor and peroxisome proliferator-activated receptor agonists; (ii) cholesteryl ester transfer protein inhibitors; (iii) HDL mimetics (ETC-216); (iv) apolipoprotein A-I synthetic peptides; and (v) HDL delipidation and reinfusion. Although they are at various stages of development, each of these therapies has promise for the treatment of cardiovascular disease in humans.

Drugs in development: targeting high-density lipoprotein metabolism and reverse cholesterol transport

PURPOSE OF REVIEW

This review summarizes currently available therapies for raising high-density lipoprotein cholesterol (HDL-C) and expands on therapies currently in development that target high-density lipoprotein cholesterol.

RECENT FINDINGS

In the realm of new high-density lipoprotein-raising therapies, there is a strong focus on high-density lipoprotein metabolism and the reverse cholesterol transport pathway. Several infusions of recombinant apoA-I Milano/phospholipid complexes appeared to reduce atheroma volume as measured by intravascular ultrasound. Both intravenous and oral apoA-I mimetic peptides are in early clinical trials. Next generation PPAR-alpha agonists are more potent at high-density lipoprotein-raising than currently available fibrates, and dual PPAR-alpha/PPAR-gamma agonists are under investigation to help correct atherogenic dyslipidemia seen in many diabetics. Two small molecule inhibitors of the cholesteryl ester transfer protein have shown promise in clinical trials at substantially raising high-density lipoprotein cholesterol.

SUMMARY

Larger scale clinical trials, including those with additional surrogate outcome measures as well as cardiovascular event outcomes are needed to further assess the benefit of newer high-density lipoprotein-raising therapies. Additional therapeutics are currently in development that target other parts of the reverse cholesterol transport pathway and, in addition to providing new potential pharmaceuticals, will help to further elucidate the atheroprotective mechanisms of high-density lipoprotein cholesterol.

HDL: the 'new' target of cardiovascular medicine

Clinical, experimental and epidemiological research has shown the undeniable causal relationship between low HDL plasma concentrations and cardiovascular disease. Low HDL levels are present in about 10% of the general population and represent the most frequent form of dyslipidemia in patients with coronary disease. Reduced HDL concentrations seem to be unable to eliminate efficiently the cholesterol excess at vascular wall level, contributing to the onset of the inflammatory response that typically occurs in the pathogenesis of atherosclerosis right from its earliest stages. The results of numerous studies quite convincingly suggest that HDL is capable of exerting anti-inflammatory activity either directly or by modulating the expression of a number of acute phase proteins. Although the therapeutic options currently available for raising HDL levels still show modest efficacy, both in experimental and pre-clinical fields, genetic investigation and specifically aimed pharmacological treatment have produced more encouraging results, shedding some light on the concrete possibility of being able to treat this disease in the very near future.

Apolipoprotein AI could be a significant determinant of epithelial integrity in rainbow trout gill cell cultures: A study in functional proteomics

The freshwater fish gill forms a barrier against an external hypotonic environment. By culturing rainbow trout gill cells on permeable supports, as intact epithelia, this study investigates barrier property mechanisms. Under symmetrical conditions the apical and basolateral epithelial surfaces contact cell culture media. Replacing apical media with water, to generate asymmetrical conditions (i.e. the situation encountered by the freshwater gill), rapidly increases transepithelial resistance (TER). Proteomic analysis revealed that this is associated with enhanced expression of pre-apolipoprotein AI (pre-apoAI). To test the physiological relevance, gill cells were treated with a dose of 50 microg ml(-1) human apolipoprotein (apoAI). This was found to elevate TER in those epithelia which displayed a lower TER prior to apoAI treatment. These results demonstrate the action of apoAI and provide evidence that the rainbow trout gill may be a site of apoAI synthesis. TER does not differentiate between the trans-cellular (via the cell membrane) and para-cellular (via intercellular tight junctions) pathways. However, despite the apoAI-induced changes in TER, para-cellular permeability (measured by polyethylene glycol efflux) remained unaltered suggesting apoAI specifically reduces trans-cellular permeability. This investigation combines proteomics with functional measurements to show how a proteome change may be associated with freshwater gill function.

Association between diet, lifestyle, metabolic cardiovascular risk factors, and plasma C-reactive protein levels

Increased C-reactive protein (CRP) levels have been associated with several of the components of the metabolic syndrome, but the direct influence of diet and lifestyle factors on CRP levels remains largely unknown. The purpose of the present study was to investigate the association between CRP and diet and lifestyle factors. Plasma CRP levels were determined by a highly sensitive enzyme-linked immunosorbent assay (ELISA) in 760 participants in the beta-Blocker Cholesterol-Lowering Asymptomatic Plaque Study (BCAPS). In accordance with previous findings, increased levels of CRP were associated with high body mass index (BMI) (P = .012), triglycerides (P = .001), systolic blood pressure (P = .019), cholesterol/high-density lipoprotein (HDL) ratio (P = .009), and low HDL cholesterol (P = .001). CRP was also increased in smokers (P = .023) and in subjects with a low vitamin C intake (P = .018). When men and women were analyzed together, there were no significant associations between CRP and dietary intake of total calories, total fat, saturated fat, monounsaturated fat, polyunsaturated fat, n-3 polyunsaturated fatty acids, n-6 polyunsaturated fatty acids, fiber, vitamin E, carotene, or selen, or in physical activity. However, in the female subgroup weak inverse relations were observed between CRP and the intake of total fat (r = -0.13, P = .011), saturated fat (r = -0.13, P = .011), monounsaturated fat (r = -0.13, P = .010), polyunsaturated fat (r = -0.14, P = .007), and n-3 PUFA (r = -0.14, P = .004). Stratified factor analyses in smoking subgroups, obese, and in under-reporters of energy, largely confirmed the results although in male never-smokers a combination of high fiber vitamin C/beta carotene intake was associated with low CRP levels. These observations suggest that CRP levels are only marginally associated with individual dietary and lifestyle factors. Surprisingly, a higher intake of fat tended to be associated with lower CRP values among women.

Genetic kininogen deficiency contributes to aortic aneurysm formation but not to atherosclerosis

Brown Norway (BN) and BN Katholiek (BN/Ka) rat strains are both susceptible to develop lesions in the internal elastic lamina (IEL) of the aorta. BN/Ka rats are characterized by a single point mutation in the kininogen gene leading to deficiency in high- and low-molecular-weight kininogen. Recently, a suggestive quantitative trait locus for lesions in the IEL of the abdominal aorta was identified in an F2 intercross between Dahl salt-sensitive (SS) and BN rats, implicating kininogen as a positional candidate gene. Therefore, BN and BN/Ka rat strains represent ideal model organisms with which to study the contribution of kininogen to the genetic predisposition to IEL lesion formation and to characterize the early events underlying vascular remodeling. Here we present data demonstrating that genetic kininogen deficiency promotes the formation of aneurysms in the abdominal aorta but not the development of atherosclerosis upon 12-wk treatment with an atherogenic diet. Aneurysm formation was associated with an enhanced elastolysis, increased expression of MMP-2 and MMP-3, downregulation of TIMP-4, and with FasL- and caspase-3-mediated apoptosis. Kininogen-deficient animals also featured changes in plasma cytokines compatible with apoptotic vascular damage, i.e., upregulation of IFN-gamma and downregulation of GM-CSF and IL-1beta. Finally, in response to atherogenic diet, kininogen-deficient animals developed an increase in HDL/total cholesterol index, pronounced fatty liver and heart degeneration, and lipid depositions in aortic media without atherosclerotic plaque formation. These findings suggest that genetic kininogen deficiency renders vascular tissue prone to aneurysmatic but not to atherosclerotic lesions.

The prevalence of coronary heart disease in Type 2 diabetic patients in Italy: the DAI study

AIMS

Type 2 diabetes is associated with at least a twofold increase in risk of coronary heart disease (CHD). We aimed to estimate the prevalence of CHD in the population of Type 2 diabetics cared for by the Italian network of outpatient diabetic units.

METHODS

The DAI (Diabetes and Informatics study group, Italian Association of Diabetologists, and Italian National Institute of Health) study is a multicentre cohort study of patients with Type 2 diabetes. Patients were classified as having CHD if they had: (i) a history for hospital admission for either an acute myocardial infarction (AMI) or angina; (ii) a positive ECG for prior AMI or angina; (iii) a positive history for coronary artery bypass graft; or (iv) a positive history for percutaneous transluminal coronary angioplasty.

RESULTS

A cohort of 19 468 patients was analysed: 3157 patients had CHD. The majority of events (80%) had occurred after the diagnosis of diabetes and were considered in the CHD prevalence estimate. The prevalence of CHD, adjusted by age and sex, was 9.9%: 11.0% male and 9.0% female. Angina without AMI occurred in 1306 patients; this condition was more frequent in females while a documented AMI was more frequent in males. Therapeutic procedures were performed more frequently in males. A positive association with CHD was found for gender, age at visit, duration of diabetes, hypertension, relatives with CHD, tryglicerides and microvascular complications.

CONCLUSIONS

The prevalence of CHD in this cohort is lower than previously reported; nevertheless, patients attending the diabetic care units may not be fully representative of the general diabetic population in Italy. Revascularization is less frequent in females than in males; microvascular complications and a worse metabolic control are significantly associated with CHD.

Targeting of scavenger receptor class B type I by synthetic amphipathic alpha-helical-containing peptides blocks lipopolysaccharide (LPS) uptake and LPS-induced pro-inflammatory cytokine responses in THP-1 monocyte cells

Human scavenger receptor class B type I, CLA-1, mediates lipopolysaccharide (LPS) binding and internalization (Vishnyakova, T. G., Bocharov, A. V., Baranova, I. N., Chen, Z., Remaley, A. T., Csako, G., Eggerman, T. L., and Patterson, A. P. (2003) J. Biol. Chem. 278, 22771-22780). Because one of the recognition motifs in SR-B1 ligands is the anionic amphipathic alpha-helix, we analyzed the effects of model amphipathic alpha-helical-containing peptides on LPS uptake and LPS-stimulated cytokine production. The L-37pA model peptide, containing two class A amphipathic helices, bound with high affinity (K(d) = 0.94 microg/ml) to CLA-1-expressing HeLa cells with a 10-fold increased capacity when compared with mock transfected HeLa cells. Both LPS and L-37pA colocalized with anti-CLA-1 antibody and directly bound CLA-1 as determined by cross-linking. SR-BI/CLA-1 ligands such as HDL, apoA-I, and L-37pA efficiently competed against iodinated L-37pA. Bacterial LPS, lipoteichoic acid, and hsp60 also competed against iodinated L-37pA. Model peptides blocked uptake of iodinated LPS in both mock transfected and CLA-1-overexpressing HeLa cells. Bound and internalized Alexa-L-37pA and BODIPY-LPS colocalized at the cell surface and perinuclear compartment. Both ligands were predominantly transported to the Golgi complex, colocalizing with the Golgi markers bovine serum albumin-ceramide, anti-Golgin97 antibody, and cholera toxin subunit B. A 100-fold excess of L-37pA nearly eliminated BODIPY-LPS binding and internalization. L-37pA and its d-amino acid analogue, D-37pA peptide were similarly effective in blocking LPS, Gram-positive bacterial wall component lipoteichoic acid and bacterial heat shock protein Gro-EL-stimulated cytokine secretion in THP-1 cells. In the same culture media used for the cytokine stimulation study, neither L-37pA nor D-37pA affected the Limulus amebocyte lysate activity of LPS, indicating that LPS uptake and cytokine stimulation were blocked independently of LPS neutralization. These results demonstrate that amphipathic helices of exchangeable apolipoproteins may represent a general host defense mechanism against inflammation.

Can change in high-density lipoprotein cholesterol levels reduce cardiovascular risk?

BACKGROUND

The cardiovascular risk reduction observed in many trials of lipid-lowering agents is greater than expected on the basis of observed low-density lipoprotein cholesterol (LDL-C) level reductions. Our objective was to explore the degree to which high-density lipoprotein cholesterol (HDL-C) level changes explain cardiovascular risk reduction.

METHODS

A systematic review identified trials of lipid-lowering agents reporting changes in HDL-C and LDL-C levels and the incidence of coronary heart disease (CHD). The observed relative risk reduction (RRR) in CHD morbidity and mortality rates was calculated. The expected RRR, given the treatment effect on total cholesterol level, was calculated for each trial with logistic regression coefficients from observational studies. The difference between observed and expected RRR was plotted against the change in HDL-C level, and a least-squares regression line was calculated.

RESULTS

Fifty-one trials were identified. Nineteen statin trials addressed the association of HDL-C with CHD. Limited numbers of trials of other therapies precluded additional analyses. Among statin trials, therapy reduced total cholesterol levels as much as 32% and LDL-C levels as much as 45%. HDL-C level increases were <10%. Treatment effect on HDL-C levels was not a significant linear predictor of the difference in observed and expected CHD mortality rates, although we observed a trend in this direction (P =.08). Similarly, HDL-C effect was not a significant linear predictor of the difference between observed and expected RRRs for CHD morbidity (P =.20).

CONCLUSIONS

Although a linear trend toward greater risk reduction was observed with greater effects on HDL-C, differences were not statistically significant. The narrow range of HDL-C level increases in the statin trials likely reduced our ability to detect a beneficial HDL-C effect, if present.