The effects of statins on high-density lipoproteins

Targeting NPC1 in Renal Cell Carcinoma

Rapidly proliferating cancer cells have a greater requirement for cholesterol than normal cells. Tumor cells are largely dependent on exogenous lipids given that their growth requirements are not fully met by endogenous pathways. Our current study shows that ccRCC cells have redundant mechanisms of cholesterol acquisition. We demonstrate that all major lipoproteins (i.e., LDL, HDL, and VLDL) have a comparable ability to support the growth of ccRCC cells and are equally effective in counteracting the antitumor activities of TKIs. The intracellular trafficking of exogenous lipoprotein-derived cholesterol appears to be distinct from the movement of endogenously synthesized cholesterol. De novo synthetized cholesterol is transported from the endoplasmic reticulum directly to the plasma membrane and to the acyl-CoA: cholesterol acyltransferase, whereas lipoprotein-derived cholesterol is distributed through the NPC1-dependent endosomal trafficking system. Expression of NPC1 is increased in ccRCC at mRNA and protein levels, and high expression of NPC1 is associated with poor prognosis. Our current findings show that ccRCC cells are particularly sensitive to the inhibition of endolysosomal cholesterol export and underline the therapeutic potential of targeting NPC1 in ccRCC.

Predictive value of neutrophil-to-apolipoprotein A1 ratio in all-cause and cardiovascular death in elderly non-valvular atrial fibrillation patients

Neutrophil-to-apolipoprotein AI ratio's (NAR's) predictive value for the elderly non-valvular atrial fibrillation (NVAF) patients' death has not been fully recognized. We consecutively enrolled 1224 elderly patients with NVAF (≥75 years). With an average follow-up of 733.35 ± 271.39 days, 222 all-cause deaths were identified. Among these, 101 were caused by cardiovascular diseases. Cox regression showed that after correcting for potential confounders, patients in the Q4 group had an increased all-cause (hazard ratio [HR] = 1.90, 95% confidence interval [CI]: 1.20-2.99) and cardiovascular death (HR = 2.59, 95% CI: 1.30-5.15) risk compared to those in the lowest NAR quartile. Kaplan-Meier analysis indicated that all-cause and cardiovascular death were higher in the high NAR than those in the lowest NAR category (log rank, all, P < 0.001). A nonlinear association was observed between death and NAR. NAR may be a promising predictive biomarker for identifying elderly NVAF patients with poor clinical prognoses.

Serum apolipoprotein B/apolipoprotein A1 ratio in relation to intervertebral disk herniation: a cross-sectional frequency-matched case-control study

Study design

This was a cross-sectional frequency-matched case–control study.

Background and aim

The serum lipid profile of lipoprotein(a) [Lp(a)] level and apolipoprotein B/apolipoprotein A1 ratio (Apo B/Apo A1) ratio were found to be more representative for serum lipid level and were recognized as the independent risk factors for various diseases. Although the blood levels of total cholesterol (TC), triglycerides (TG), low-density lipoprotein cholesterol (LDL-C), and high-density lipoprotein cholesterol (HDL-C) were found to be associated with symptomatic intervertebral disk herniation (IDH), no studies to date have evaluated the association of Apo AI, Apo B, Lp(a), and Apo B/Apo AI levels with symptomatic IDH. This study aimed to assess the link between blood lipid levels and symptomatic IDH.

Method

The study included 1839 Chinese patients. Of these, 918 patients were diagnosed with IDH and enrolled in the experimental group. A control group of 921 patients underwent a physical examination during the same period. The serum lipid levels of TC, TG, LDL-C, HDL-C, Lp(a), Apo B, and Apo B/Apo AI were examined and analyzed. The control group comprised randomly selected patients who met the baseline levels of the aforementioned lipid molecules.

Results

Patients with IDH exhibited significantly higher TC, TG, LDL, Apo B, and Lp(a) levels than controls. The percentage of high TC, high TG, high LDL, high Apo B, and high Lp(a) were obviously higher in the IDH group than in the control group. However, hyperlipidemia had no relationship with the degenerated segment of the IDH (P = 0.201). The odds ratio (OR) for the incidence of IDH with elevated levels of LDL-C, TC, TG, Lp(a), Apo B, and Apo B/Apo AI was 1.583, 1.74, 1.62, 1.58, 1.49, and 1.39, respectively. The correlation analysis revealed the correlation between elevated LDL-C, TC, TG, Apo B, Lp(a), and incidence of IDH was significant (R²_LDL = 0.017; R²_TC = 0.004; R²_TG = 0.015; R²_{Apo B} = 0.004; R²_Lp(a) = 0.021) (P < 0.05).

Conclusion

This study suggested that elevated levels of serum TC, TG, LDL, Apo B, Lp(a), and Apo B/Apo AI were associated with a higher risk of IDH. This study provided useful information to identify a population that might be at risk of developing IDH based on elevated lipid levels.

Use of Statins as Lipid Lowering Agent in Hypercholesterolemia in a Tertiary Care Hospital: A Descriptive Cross-sectional Study

INTRODUCTION

Lipids contribute to atherosclerosis and obesity that can lead to different cardiovascular diseases. Statins are hydroxymethylglutaryl reductase inhibitors that effectively lower the cholesterol level. It is widely prescribed in the treatment of hypercholesterolemia. Thus it optimizes the lipoprotein profile. The selection of a particular drug by the practitioner should be primarily based on clinical outcome. This study was conducted to find the type of statins that are most preferred by the doctors for treating dyslipidemia and preferred the fixed-dose in a tertiary care hospital.

METHODS

This was a descriptive cross-sectional study conducted among the practicing doctors of Kathmandu Medical College from July to August 2020. Ethical approval was taken from the Institutional Review Committee of the college (Ref: 207202006). Convenient sampling was done. A semi-structured questionnaire was used with consent. The data were analyzed with Social Statistical Package for the Social Sciences version 20.

RESULTS

Statins, with the score 4.25 was accounted for most preferred for the treatment of dyslipidemia. Among different statins, atorvastatin with a score of 4.48 was most popular followed by rosuvastatin 2.9 score and simvastatin 2.1 scores.

CONCLUSIONS

Statins were the most preferred agents for the treatment of dyslipidemia. Although different types of statins ought to have similar efficacy in treating dyslipidemia, atorvastatin was found to be popular and the most commonly prescribed one. The most common side effect reported with statins was myopathy.

Effect of Rooibos (Aspalathus linearis) extract on atorvastatin-induced toxicity in C3A liver cells

Rooibos (Aspalathus linearis) has various health benefits. Two case studies have associated chronic Rooibos consumption with conventional prescription medications, including atorvastatin (ATV), with hepatotoxicity. Statins act by inhibiting hydroxymethylglutaryl‐coenzyme A reductase, a rate‐limiting enzyme in cholesterol synthesis. Although rare, statins are potentially hepatotoxic. The aim was to investigate interactions between aspalathin‐rich Rooibos extract GRT™ and ATV‐induced hepatotoxicity in C3A liver cells cultured with and without palmitate. Effects of co‐treatment of GRT + ATV on cell viability, oxidative stress, apoptosis, mitochondrial integrity, and cellular reactive oxygen species (ROS) production were assessed. Significantly increased ROS production was observed in cells exposed to ATV and palmitate. Combination therapy of GRT + ATV also showed significant increases in ROS production. Under palmitate‐treated conditions, ATV‐induced significant apoptosis which was not ameliorated by GRT + ATV co‐treatment. Despite studies purporting hepatoprotection from Rooibos, our study showed that GRT was unable to modulate ATV‐induced hepatotoxic effects in this model.

Current and future therapies for addressing the effects of inflammation on HDL cholesterol metabolism

Cardiovascular disease (CVD) is a major cause of morbidity and mortality worldwide. Inflammatory processes arising from metabolic abnormalities are known to precipitate the development of CVD. Several metabolic and inflammatory markers have been proposed for predicting the progression of CVD, including high density lipoprotein cholesterol (HDL-C). For ~50 years, HDL-C has been considered as the atheroprotective 'good' cholesterol because of its strong inverse association with the progression of CVD. Thus, interventions to increase the concentration of HDL-C have been successfully tested in animals; however, clinical trials were unable to confirm the cardiovascular benefits of pharmaceutical interventions aimed at increasing HDL-C levels. Based on these data, the significance of HDL-C in the prevention of CVD has been called into question. Fundamental in vitro and animal studies suggest that HDL-C functionality, rather than HDL-C concentration, is important for the CVD-preventive qualities of HDL-C. Our current review of the literature positively demonstrates the negative impact of systemic and tissue (i.e. adipose tissue) inflammation in the healthy metabolism and function of HDL-C. Our survey indicates that HDL-C may be a good marker of adipose tissue health, independently of its atheroprotective associations. We summarize the current findings on the use of anti-inflammatory drugs to either prevent HDL-C clearance or improve the function and production of HDL-C particles. It is evident that the therapeutic agents currently available may not provide the optimal strategy for altering HDL-C metabolism and function, and thus, further research is required to supplement this mechanistic approach for preventing the progression of CVD.

LINKED ARTICLES

This article is part of a themed section on Targeting Inflammation to Reduce Cardiovascular Disease Risk. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v174.22/issuetoc and http://onlinelibrary.wiley.com/doi/10.1111/bcp.v82.4/issuetoc.

Serum lipid levels are positively correlated with lumbar disc herniation--a retrospective study of 790 Chinese patients

Background

Abnormal serum lipid levels have been shown to be associated with the occurrence of atherosclerosis, but little is known about the relationships of them with the risk of developing intervertebral disc degeneration (IVDD) in Chinese population.

Methods

We performed a case–control study to assess the relationship between serum lipid levels and lumbar disc degeneration. A total of 790 Chinese patients were recruited for this study at the time of hospitalization. We examined fasting serum lipid levels of total cholesterol (TC), triglycerides (TG), low-density lipoprotein cholesterol (LDL-C) and high-density lipoprotein cholesterol (HDL-C). 396 patients (235 men and 161 women; mean age: 41.07 years) underwent surgery for single-level lumbar disc herniation. A control group of 394 patients (225 men and 169 women; mean age: 42.1 years) underwent surgery for wounded lower limbs during the same period. Patients in the control group were collected randomly from among patients who were age- and sex-matched patients with the case group.

Results

Patients with lumbar disc herniation had significantly higher TC and LDL-C serum concentrations (P < 0.001 for both) than controls. Percentage of High-TC, High-TG, High-LDL-C, borderline High-TC and borderline High-LDL-C were significantly higher in the disc herniation group (P = 0.017, P = 0.002, P = 0.039, P =0.002 and P < 0.001, respectively). Ratios of TC/HDL-C and LDL-C/HDL-C were significantly associated with disc herniation (P < 0.001 for both). Logistic regression revealed that patients with higher serum LDL-C levels had a higher risk of disc herniation, in which odds ratio (OR) was 1.462 and confidence interval (CI) was 1.179 ~ 1.813. Moreover, patients with High-TG and borderline High-LDL-C had a higher probability of disc herniation (OR: 2.974, CI: 1.488 ~ 5.945, statistical power: 100 %; OR: 1.626, CI: 1.012 ~ 2.612, statistical power: 61.4 %, respectively). However, hyperlipidaemia did not seem to be associated with the herniated segment of the lumbar intervertebral disc (p = 0.374).

Conclusions

The present study suggests that dyslipidaemia may be associated with a higher risk of developing lumbar disc herniation. Serum lipid levels could be a useful predictor for intervertebral disc degeneration in Chinese population.

Should low high-density lipoprotein cholesterol (HDL-C) be treated?

The first observations linking a low serum level of HDL-C to increased risk for cardiovascular disease were made over 50 years ago. High serum levels of HDL-C appear to protect against the development of atherosclerotic disease, while low serum levels of this lipoprotein are among the most important predictors of atherosclerotic disease in both men and women and people of all racial and ethnic groups throughout the world. It has long been assumed that therapeutic interventions targeted at raising HDL-C levels would lower risk for such cardiovascular events as myocardial infarction, ischemic stroke, and death. Even after five decades of intensive investigation, evidence to support this assumption has been fleeting. A number of post hoc analyses of randomized controlled trials and meta-analyses suggest that HDL-C raising, particularly when coupled with aggressive LDL-C reduction, impacts risk for cardiovascular events and rates of progression of atherosclerotic disease. Unfortunately, four recent prospective trials performed with the intent of testing the "HDL hypothesis" (ILLUMINATE, dal-OUTCOMES, AIM-HIGH, and HPS2-THRIVE) failed to meet their primary composite endpoints. These results have lead many clinicians and investigators to question the validity of the assumption that HDL-C raising reduces risk for cardiovascular events. Additional trials with other drugs are underway. In the meantime, HDL-C cannot be considered a target of therapy. Given the complexity of the HDL proteome and lipidome, there is biological plausibility for how HDL particles might exert atheroprotection. We explore the evidence supporting the inverse relationship between HDL-C and cardiovascular disease risk, documented mechanisms by which HDL particles may exert atheroprotection, and the findings either supporting or negating specific therapeutic interventions in patients afflicted with low HDL-C.

Inventing new medicines: The FGF21 story

Since the discovery of insulin in 1921, protein therapeutics have become vital tools in the treatment of diabetes mellitus. This heritage has been extended with the comparatively recent introduction of recombinant and re-engineered insulins, in addition to the advent of GLP1 agonists. FGF21 represents an example of a novel experimental protein therapy which is able to induce favorable metabolic effects in various species ranging from rodents to man.

The aim of this review is to communicate the story of the FGF21 drug discovery path from identification in a functional in vitro screen, to the eventual evaluation of its utility in patients. Given that the development of FGF21 advanced hand-in-hand with rapidly evolving scientific research around this target, we have also attempted to describe our view of recent developments regarding the mechanistic understanding of FGF21 biology.

Statins and lipid metabolism: an update

PURPOSE OF REVIEW

The reduction in cardiovascular disease risk by statins is well established. This risk reduction has mostly been attributed to decreases in plasma LDL cholesterol and other pleiotropic effects of statins. Emerging evidence indicates that statins exert multiple effects on lipoprotein metabolism, including chylomicrons and HDLs.

RECENT FINDINGS

Kinetic and in-vitro studies have documented that the effects of statins on the metabolism of different lipoproteins are for the most part the direct consequence of cholesterol biosynthesis inhibition and the subsequent change in transcription factors and cell signaling, regulating different aspects of lipoprotein metabolism. Differences in pharmacokinetics and pharmacodynamics among statins lead to diverse biological outcomes.

SUMMARY

The current review summarizes recent experimental evidence highlighting the different effects of statins on cellular pathways regulating gene expression. Understanding the basic mechanisms by which different statins regulate lipoprotein metabolism will lead to improved strategies for the prevention and treatment of specific lipoprotein disorders.

Statin treatment improves plasma lipid levels but not HDL subclass distribution in patients undergoing percutaneous coronary intervention

Despite the established efficacy of statin therapy, the risk of cardiovascular events remains high in many patients. We examined high-density lipoprotein (HDL) subclass distribution profiles among statin-treated coronary heart disease (CHD) patients undergoing percutaneous coronary intervention (PCI). Plasma HDL subclasses were measured in 85 patients with established CHD and quantified by two-dimensional gel electrophoresis and immunoblotting. In CHD patients with statin treatment, the mean value of total cholesterol (TC) reached the desirable level and the triacylglycerol level (TAG) was borderline high. Moreover, low density lipoprotein cholesterol (LDL-C), high density lipoprotein cholesterol (HDL-C), apolipoproteinA-I, and apolipoproteinB-100 levels in these patients resembled those in normolipidemic healthy subjects. The HDL subclass did not show a normal distribution and was characterized by the lower large-sized HDL(2b) contents and higher contents of small-sized preβ₁-HDL in CHD patients, compared to those in normolipidemic control subjects. Multiple stepwise regression analysis revealed that the severity of coronary stenosis, determined by the Gensini Score, was significantly and independently predicted by HDL(2b) and HDL(3b). Statin therapy was effective in modifying plasma lipids levels, but not adequate as a monotherapy to normalize the HDL subclass distribution phenotype of patients with CHD undergoing PCI. The HDL subclass distribution may aid in risk stratification, especially in patients with CHD and therapeutic LDL-C and HDL-C levels.

Reverse cholesterol transport in familial hypercholesterolemia

PURPOSE OF REVIEW

Familial hypercholesterolemia is characterized by a major elevation in circulating LDL-cholesterol levels, cholesterol deposition within the arterial wall and an increased risk of premature coronary artery disease. The reverse cholesterol transport (RCT) is now considered as a key process that protects against development of atherosclerosis. The major antiatherogenic action of HDL particles is intimately linked to their determinant role in RCT pathway. However, the steady-sate of HDL-cholesterol levels does not represent the optimal marker to evaluate the efficiency of the RCT in all circumstances.

RECENT FINDINGS

By using ex-vivo systems for the evaluation of the efficacy of RCT a strong inverse relationship between HDL efflux capacity from macrophages and atherosclerosis progression has been demonstrated. Low HDL-C phenotype observed in familial hypercholesterolemia patients is associated with defective capacities of HDL particles to mediate major steps of the centripetal movement of cholesterol from peripheral cells to feces. However, current available treatment used to reduce LDL-C to therapeutic goals does not correct altered functions of HDL particles in humans.

SUMMARY

In the context of familial hypercholesterolemia, a growing body of evidence suggests that impaired efficacy of the RCT pathway contributes significantly to the progression of atherosclerosis.

Symptomatic disc herniation and serum lipid levels

Insufficient blood supply to the intervertebral disc (IVD) has been proposed to play a role as causative factor in IVD degeneration. There is an association between IVD diseases and increased risk of dying of ischaemic heart disease. Obesity and tobacco are potential risk factors for degenerative IVD disease. High blood cholesterol and triglycerides serum levels are risk factors for atherosclerosis, and could be responsible for a decreased in the blood supply to the already poor vascularized IVD. We performed a frequency-matched case-control study to determine the serum levels of patients with symptomatic herniated lumbar disc. We examined the fasting serum lipid levels in 384 subjects who were operated at our institution. Group 1 included 169 consecutive patients (115 men and 54 women; mean age: 59.1 years, range 29-85) who underwent surgery for symptomatic disc herniation. Group 2 (control group) included 169 patients (115 men and 54 women; mean age: 61 years, range 26-86) who underwent arthroscopic meniscectomy for a meniscal tear in the same period. These patients were frequency-matched by age (within 3 years) and gender with patients of Group 1. Sera were extracted from blood samples and the concentrations of total cholesterol (TC) and triglycerides (TG) were determined. When comparing the two groups, patients with symptomatic herniated lumbar disc showed statistically significant higher triglyceride concentration (P = 0.02) and total cholesterol concentration (P = 0.01). Serum lipid levels may be a risk factor for IVD pathology. An enhanced understanding of these factors holds the promise of new approaches to the prevention and management of IVD pathology.

High-density lipoprotein (HDL) cholesterol: leveraging practice-based biobank cohorts to characterize clinical and genetic predictors of treatment outcome

Over the past decade, large multicenter trials have unequivocally demonstrated that decreasing low-density lipoprotein (LDL) cholesterol can reduce both primary and secondary cardiovascular events in patients at risk. However, even in the context of maximal LDL lowering, there remains considerable residual cardiovascular risk. Some of this risk can be attributed to variability in high-density lipoprotein (HDL) cholesterol. As such, there is tremendous interest in defining determinants of HDL homeostasis. Risk prediction models are being constructed based upon (1) clinical contributors, (2) known molecular determinants and (3) the genetic architecture underlying HDL cholesterol levels. To date, however, no single resource has combined these factors within the context of a practice-based data set. Recently, a number of academic medical centers have begun constructing DNA biobanks linked to secure encrypted versions of their respective electronic medical record. As these biobanks combine resources, the clinical community is in a position to characterize lipid-related treatment outcome on an unprecedented scale.

Effect of rosiglitazone on HDL metabolism in subjects with metabolic syndrome and low HDL

Treatment with the peroxisome proliferator-activated receptor γ agonist rosiglitazone has been reported to increase HDL-cholesterol (HDL-C) levels, although the mechanism responsible for this is unknown. We sought to determine the effect of rosiglitazone on HDL apolipoprotein A-I (apoA-I) and apoA-II metabolism in subjects with metabolic syndrome and low HDL-C. Subjects were treated with placebo followed by rosiglitazone (8 mg) once daily. At the end of each 8 week treatment, subjects (n = 15) underwent a kinetic study to measure apoA-I and apoA-II production rate (PR) and fractional catabolic rate. Rosiglitazone significantly reduced fasting insulin and high-sensitivity C-reactive protein (hsCRP) and increased apoA-II levels. Mean apoA-I and HDL-C levels were unchanged following rosiglitazone treatment, although there was considerable individual variability in the HDL-C response. Rosiglitazone had no effect on apoA-I metabolism, whereas the apoA-II PR was increased by 23%. The change in HDL-C in response to rosiglitazone was significantly correlated with the change in apoA-II concentration but not to changes in apoA-I, measures of glucose homeostasis, or hsCRP. Treatment with rosiglitazone significantly increased apoA-II production in subjects with metabolic syndrome and low HDL-C but had no effect on apoA-I metabolism. The change in HDL-C in response to rosiglitazone treatment was unrelated to effects on apoA-I, instead being related to the change in the metabolism of apoA-II.

Changes in remnant and high-density lipoproteins associated with hormone therapy and progression of coronary artery disease in postmenopausal women

OBJECTIVE

This study examined the effect of hormone therapy (HT) on the plasma concentration of remnant lipoprotein cholesterol (RLP-C) and high-density lipoprotein (HDL) subpopulations and the contribution of HT-related changes in these lipoproteins to the progression of coronary heart disease (CHD) in postmenopausal women.

METHODS

Study participants were 256 women who completed the Estrogen Replacement and Atherosclerosis (ERA) trial, a placebo-controlled, randomized trial that examined the effects of 3.2 years of conjugated equine estrogen (CEE, 0.625 mg/day) or CEE (0.625 mg/day) plus medroxyprogesterone acetate (MPA, 2.5mg/day) on postmenopausal women with established coronary atherosclerosis. Quantitative coronary angiography and plasma RLP-C and HDL subpopulations were assessed at baseline and at follow-up.

RESULTS

Relative to placebo, both CEE and CEE+MPA caused a significant reduction in plasma RLP-C concentrations and a significant increase in alpha1 and alpha2 HDL subpopulations. However, in the HT-treated subjects, faster progression of coronary atherosclerosis was observed in women who experienced the greatest reductions in RLP-C and in prebeta1 HDL subpopulations.

CONCLUSIONS

Our data suggest that individual variability in RLP-C and HDL subpopulation response to HT is a predictor of CHD progression. Lipoprotein response to HT may be an indirect marker of susceptibility to other harmful effect of HT in postmenopausal women with established CHD or an indication of formation of dysfunctional lipoproteins.

When high is low: raising low levels of high-density lipoprotein cholesterol

Low serum levels of high-density lipoprotein cholesterol (HDL-C) are highly prevalent and are recognized as an independent risk factor for cardiovascular morbidity (myocardial infarction, stroke, peripheral arterial disease, and restenosis after coronary stenting) and mortality. HDL plays an important role in modulating atherogenesis, although its functions are varied and complex and the mechanisms for its antiatherogenic effects have not been completely elucidated. The inverse relationship between HDL-C and cardiovascular risk is well established, and epidemiologic studies and clinical trials have provided ample evidence that higher levels of HDL-C are vasculoprotective. Although considerable interest exists in the development of novel approaches to raise serum HDL-C and to augment HDL functionality, this article discusses currently available therapies to raise suboptimal levels of this important lipoprotein.

Ezetimibe: cholesterol lowering and beyond

Ezetimibe is a cholesterol absorption inhibitor that blocks the intestinal absorption of both biliary and dietary cholesterol. It appears to exert its effect by blocking intestinal sterol transporters, specifically Niemann-Pick C1-like 1 proteins, thereby inhibiting the intestinal absorption of cholesterol, phytosterols and certain oxysterols. Ezetimibe monotherapy and in combination with statin therapy is primarily indicated for lowering LDL-cholesterol levels. In addition, it may favorably affect other parameters that could potentially further reduce atherosclerotic coronary heart disease risk, such as raising HDL-cholesterol and lowering levels of triglycerides, non-HDL-cholesterol, apolipoprotein B and remnant-like particle cholesterol. Further effects of ezetimibe include a reduction in circulating phytosterols and oxysterols and, when used in combination with statins, a reduction in high-sensitivity C-reactive protein. The clinical significance of the LDL-cholesterol lowering and other effects of ezetimibe is being evaluated in clinical outcome studies.

HDL, ABC transporters, and cholesterol efflux: implications for the treatment of atherosclerosis

High-density lipoprotein (HDL) has been identified as a potential target in the treatment of atherosclerotic vascular disease. The failure of torcetrapib, an inhibitor of cholesteryl ester transfer protein (CETP) that markedly increased HDL levels in a clinical trial, has called into doubt the efficacy of HDL elevation. Recent analysis suggests that failure may have been caused by off-target toxicity and that HDL is functional and promotes regression of atherosclerosis. New studies highlight the central importance of the ATP-binding cassette (ABC) transporters ABCA1 and ABCG1 in reducing macrophage foam cell formation, inflammation, and atherosclerosis. A variety of approaches to increasing HDL may eventually be successful in treating atherosclerosis.

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.

Weight loss, dietary advice and statin therapy in non-alcoholic fatty liver disease: a retrospective study

BACKGROUND

Studies have shown that weight loss can have a favourable effect upon non-alcoholic fatty liver disease (NAFLD). However, the most effective means of achieving weight loss and safety profile of lipid-lowering drugs in the presence of NAFLD is unknown.

AIM

To investigate the effect of dietary advice and lipid-lowering drugs, particularly statins, on patients with NAFLD and dyslipidaemia.

DESIGN

Observational records based study.

METHODS

We studied 71 patients with NAFLD and dyslipidaemia diagnosed and treated between 1996 and 2002 at University Hospital Lewisham. Some were referred to a dietician for weight loss advice as part of their management. After treatment all patients were assessed for changes in weight, serum alanine transaminase (ALT) and serum lipids including serum cholesterol, serum high density lipoprotein (HDL) and serum triglycerides.

RESULTS

Thirty-seven male and 34 female patients with NAFLD and dyslipidaemia were followed up for a mean period of 440 +/- 374 days (median 335). Regression analysis revealed a significant association between changes in weight and changes in serum ALT (p < 0.039). Dietary advice failed to reduce body weight but significantly lowered the serum cholesterol to HDL ratio (p = 0.05). Only 15.4% of patients taking statins experienced a rise in serum ALT > or = 40 U/l, and in each case the rise was transient, returning near baseline or below without discontinuation of statin treatment.

CONCLUSIONS

Weight loss appears to improve NAFLD, and dietary advice and lipid-lowering drugs may be beneficial for patients with NAFLD and dyslipidaemia even if weight loss is not achieved. Statins appear to be safe and efficacious in this group.

Dose-dependent regulation of high-density lipoprotein metabolism with rosuvastatin in the metabolic syndrome

BACKGROUND

Low plasma concentration of high-density lipoprotein (HDL) cholesterol is a risk factor for cardiovascular disease and a feature of the metabolic syndrome. Rosuvastatin has been shown to increase HDL cholesterol concentration, but the mechanisms remain unclear.

METHODS AND RESULTS

Twelve men with the metabolic syndrome were studied in a randomized, double-blind, crossover trial of 5-wk therapeutic periods with placebo, 10 mg/d rosuvastatin, or 40 mg/d rosuvastatin, with 2-wk placebo washout between each period. Compared with placebo, there was a significant dose-dependent increase in HDL cholesterol, HDL particle size, and concentration of HDL particles that contain apolipoprotein A-I (LpA-I). The increase in LpA-I concentration was associated with significant dose-dependent reductions in triglyceride concentration and LpA-I fractional catabolic rate, with no changes in LpA-I production rate. There was a significant dose-dependent reduction in the fractional catabolic rate of HDL particles containing both apolipoprotein A-I and A-II (LpA-I:A-II), with concomitant reduction in LpA-I:A-II production rate, and hence no change in LpA-I:A-II concentration.

CONCLUSIONS

Rosuvastatin dose-dependently increased plasma HDL cholesterol and LpA-I concentrations in the metabolic syndrome. This could relate to reduction in plasma triglycerides with remodeling of HDL particles and reduction in LpA-I fractional catabolism. The findings contribute to understanding mechanisms for the HDL-raising effect of rosuvastatin in the metabolic syndrome with implications for reduction in cardiovascular disease.

Lipoprotein lipase HindIII polymorphism influences HDL-cholesterol levels in statin-treated patients with coronary artery disease

BACKGROUND

HDL-cholesterol (HDL-C) is a recognized athero-protective factor and low levels of HDL-C occur frequently in patients with coronary artery disease. Regulation of HDL-C level most probably results from the interaction of genes involved in lipoprotein metabolism and also from non-genetic factors. We studied associations and interactions among HindIII polymorphisms of the lipoprotein lipase gene LPL and selected non-genetic factors with respect to HDL-C levels in patients with coronary artery disease.

PATIENTS AND METHODS

288 Slovak patients (35% women) with documented coronary artery disease, age (mean +/- SEM) 60 +/- 1 years and BMI 29 +/- 0.3 kg/m(2), were examined and genotyped for LPL HindIII (rs320) using a PCR/RFLP method. HDL-C levels were determined in a direct enzymatic assay.

RESULTS

In the sample overall there were no significant differences across the LPL genotypes in adjusted HDL-C levels or in other lipids, although a trend toward higher HDL-C and lower triglycerides in H-H- homozygotes was observed. Multiple linear regression identified a significant interaction between LPL HindIII and statin treatment, which together with sex and diabetes explained 12.1% of HDL-C variance. Accordingly, in statin-treated patients we observed significant stepwise increments of the HDL-C level related to the increasing number of H- alleles (P = 0.04 for linear trend), whereas no such association was observed in patients without hypolipidemic treatment. H-H- homozygotes had a 16% (0.19 mmol/l) higher level of HDL-C than the H+H+ homozygotes (P = 0.06).

CONCLUSION

HDL-C may be influenced by an interaction between statin treatment and LPL HindIII genotype. However, the effect of this interaction appears to be small when compared with the effect of non-genetic factors. This finding requires replication in a pharmacogenetic study.

High-density lipoprotein metabolism: potential therapeutic targets

It is well recognized that the lowering of low-density lipoprotein (LDL) cholesterol can substantially reduce coronary artery disease (CAD)-related morbidity and mortality. The prevention and management of CAD has chiefly focused on 1 component of the lipid profile: the reduction of LDL cholesterol. Yet, the majority of patients in both the primary and secondary prevention settings continue to experience significant residual risk for acute cardiovascular events even when their LDL cholesterol is lowered aggressively with combinations of lifestyle modification and pharmacologic intervention. As a result, there is increased focus on targeting and treating low serum levels of high-density lipoprotein (HDL) cholesterol in an effort to further reduce risk for cardiovascular events, including myocardial infarction, unstable angina, ischemic stroke, and death. Epidemiologically high serum levels of HDL cholesterol are associated with reduced risk for the development of atherosclerotic disease. HDL particles are believed to be antiatherogenic secondary to their capacity to drive reverse cholesterol transport and antagonize pathways of inflammation, thrombosis, and oxidation. HDL cholesterol can be quite challenging to raise in many individuals because of the large number of polymorphisms in the genes, enzymes, cell surface receptors, and apoproteins that regulate the serum concentrations, functionality, and patterns of metabolism of HDL particles This article reviews HDL metabolism and established as well as emerging therapeutic approaches to raising serum concentrations of this fascinating and complex lipoprotein.

Increasing apoA-I production as a target for CHD risk reduction

Dyslipidemia leading to coronary heart diseases (CHD) enables venues to prevent or treat CHD by other strategies than only lowering serum LDL cholesterol (LDL-C) concentrations, which is currently the most frequently targeted change. Unlike LDL-C, elevated high-density lipoprotein cholesterol (HDL-C) concentrations may protect against the development of CHD as demonstrated in numerous large-scale epidemiological studies. In this review we describe that besides elevating serum HDL-C concentrations by increasing alpha-HDL particles, approaches to elevate HDL-C concentrations by increasing pre-beta HDL particle concentrations seems more attractive. Besides infusion of apoA-I(Milano), using apoA-I mimetics, or delipidation of alpha-HDL particles, elevating de novo apoA-I production may be a suitable target to functionally increase pre-beta HDL particle concentrations. Therefore, a detailed description of the molecular pathways underlying apoA-I synthesis and secretion, completed with an overview of known effects of pharmacological and nutritional compounds on apoA-I synthesis will be presented. This knowledge may ultimately be applied in developing dietary intervention strategies to elevate apoA-I production and serum HDL-C concentrations and consequently lower CHD risk.

A 12-Week, Prospective, Open-Label Analysis of the Effect of Rosuvastatin on Triglyceride-Rich Lipoprotein Metabolism in Patients with Primary Dyslipidemia

BACKGROUND

Although the effect of statins on lowering low-density lipoprotein cholesterol (LDL-C) has been extensively studied, their hypotriglyceridemic capacity is not fully understood.

OBJECTIVE

The present study examined clinical and laboratory factors potentially associated with the triglyceride (TG)-lowering effect of rosuvastatin.

METHODS

Eligible patients had primary dyslipidemia and a moderate risk of heart disease. Patients were prescribed rosuvastatin 10 mg/d in an open-label fashion and kept 3-day food diaries. Laboratory measurements, performed at baseline and 12 weeks, included serum lipid parameters (total cholesterol [TC], TGs, LDL-C, high-density lipoprotein cholesterol [HDL-C], and apolipoprotein [apo] levels), non-lipid metabolic variables (including carbohydrate metabolism parameters and renal, liver, and thyroid function tests), and LDL-subfraction profile (by high-resolution 3% polyacrylamide gel electrophoresis). Tolerability was assessed at each visit.

RESULTS

Participants were 75 hyperlipidemic patients (39 men and 36 women; mean age, 51.7 years). At 12 weeks, TC levels were reduced by 35.1% (P < 0.001), TGs by 15.2% (P < 0.001), LDL-C by 48.5% (P < 0.001), apoE by 35.4% (P < 0.001), and apoE by 17.3% (P < 0.001) from baseline, whereas HDL-C and apoA1 levels were not significantly changed. Stepwise linear regression analysis showed that baseline TG levels were most significantly correlated (R(2) = 42.0%; P < 0.001) with the TG-lowering effect of rosuvastatin, followed by the reduction in apoCIII levels (R(2) = 13.6%; P < 0.01). Rosuvastatin use was associated with a reduction in cholesterol mass of both large LDL particles (mean [SD], from 150.5 [36.6] to 90.5 [24.3] mg/dL; P < 0.001) and small, dense LDL (sdLDL) particles (from 11.5 [8.4] to 6.6 [4.5] mg/dL; P < 0.001). Rosuvastatin had no effect on cholesterol distribution of the LDL subfractions (mean [SD], large particles, from 90.8% [7.0%] to 91.8% [5.1%]; sdLDL, from 7.1% [4.7%] to 7.5% [4.8%]) or the mean LDL particle size (from 26.5 [4.2] to 26.6 [4.0] rim). A significant increase in mean LDL particle size after rosuvastatin treatment (mean [SD], from 26.4 [0.4] to 26.9 [0.4] rim; P = 0.02) was observed only in patients with baseline TG levels > or =120 mg/dL. No serious adverse events requiring study treatment discontinuation were reported. One patient who presented with headache and 2 patients who presented with fatigue quickly recovered without discontinuing rosuvastatin treatment. A posttreatment elevation in aminotransferase levels <3-fold the upper limit of normal (ULN) was recorded in 5 (6.7%) patients, and 2 (2.7%) patients experienced elevated creatine kinase concentrations <5-fold ULN.

CONCLUSION

Baseline TG levels were the most important independent variable associated with the TG-lowering effect of rosuvastatin.

Effect of paraoxonase 1 polymorphisms on the response of lipids and lipoprotein-associated enzymes to treatment with fluvastatin

BACKGROUND

Decreased paraoxonase 1 (PON1) and increased total serum lipoprotein-associated phospholipase A(2) (Lp-PLA(2)) activities are suggested to be risk factors for vascular disease. Common PON1 genetic polymorphisms (Q192R and L55M) significantly affect PON1 activity and may also influence high-density lipoprotein (HDL)-associated Lp-PLA(2) activity. However, little is known about the possible effect of PON1 common genetic polymorphisms on the response of lipids as well as PON1 and Lp-PLA(2) activities to treatment with statins.

METHODS

Two hundred two hypercholesterolemic patients were treated with fluvastatin 40 mg/day. Fasting serum lipids, Q192R and L55M PON1 polymorphisms as well as PON1 and Lp-PLA(2) (total serum and HDL-associated) activities were determined before and after 6 months of treatment.

RESULTS

Fluvastatin treatment did not affect HDL-cholesterol or apolipoprotein (apo) AI but resulted in significant decreases in total cholesterol, triglycerides, low-density lipoprotein-cholesterol, apo B and apo E, as well as total serum Lp-PLA(2) activity. In contrast, PON1 activity significantly increased. None of these changes was influenced by Q192R or L55M PON1 polymorphisms. Overall, HDL-Lp-PLA(2) did not change but L55M polymorphism significantly influenced its response to fluvastatin. Specifically, LL homozygotes experienced a significant increase, while M carriers (LM or MM) experienced a non-significant decrease in HDL-Lp-PLA(2) activity (p = 0.030 between groups).

CONCLUSIONS

Q192R and L55M PON1 polymorphisms did not affect the response of lipids, PON1 and total serum Lp-PLA(2) to treatment with a statin. However, L55M PON1 polymorphism significantly modulated the response of HDL-Lp-PLA(2). It should be noted that this is an association study and therefore provides no proof but only indication that PON1 may also exert Lp-PLA(2) activity in HDL.

High-density lipoprotein and the risk of recurrent venous thromboembolism

BACKGROUND

High-density lipoprotein (HDL) protects against arterial atherothrombosis, but it is unknown whether it protects against recurrent venous thromboembolism.

METHODS AND RESULTS

We studied 772 patients after a first spontaneous venous thromboembolism (average follow-up 48 months) and recorded the end point of symptomatic recurrent venous thromboembolism, which developed in 100 of the 772 patients. The relationship between plasma lipoprotein parameters and recurrence was evaluated. Plasma apolipoproteins AI and B were measured by immunoassays for all subjects. Compared with those without recurrence, patients with recurrence had lower mean (+/-SD) levels of apolipoprotein AI (1.12+/-0.22 versus 1.23+/-0.27 mg/mL, P<0.001) but similar apolipoprotein B levels. The relative risk of recurrence was 0.87 (95% CI, 0.80 to 0.94) for each increase of 0.1 mg/mL in plasma apolipoprotein AI. Compared with patients with apolipoprotein AI levels in the lowest tertile (<1.07 mg/mL), the relative risk of recurrence was 0.46 (95% CI, 0.27 to 0.77) for the highest-tertile patients (apolipoprotein AI >1.30 mg/mL) and 0.78 (95% CI, 0.50 to 1.22) for midtertile patients (apolipoprotein AI of 1.07 to 1.30 mg/mL). Using nuclear magnetic resonance, we determined the levels of 10 major lipoprotein subclasses and HDL cholesterol for 71 patients with recurrence and 142 matched patients without recurrence. We found a strong trend for association between recurrence and low levels of HDL particles and HDL cholesterol.

CONCLUSIONS

Patients with high levels of apolipoprotein AI and HDL have a decreased risk of recurrent venous thromboembolism.

Nicotinic acid and other therapies for raising high-density lipoprotein

PURPOSE OF REVIEW

The purpose of this review is to describe the high-density-lipoprotein-raising effect of nicotinic acid and the clinical effects of treatment on cardiovascular diseases, particularly in combination with statins. Other treatments for raising high-density lipoprotein, including changes in lifestyle, other drugs and infusions of 'synthetic' (reconstituted) high-density lipoprotein will be summarized.

RECENT FINDINGS

Treatment of atherosclerotic cardiovascular disease with nicotinic acid and statin results in a pronounced increase of protective high-density lipoprotein cholesterol and reduces morbidity/mortality. Addition of prolonged-release nicotinic acid to ongoing treatment with statin raises high-density lipoprotein cholesterol and induces regression of atherosclerosis that otherwise would progress during statin treatment. Several new high-density lipoprotein-raising drugs in clinical trials are reported. New proposed mechanisms for the broad-spectrum lipid effects of nicotinic acid are described.

SUMMARY

Low plasma concentration of high-density lipoprotein is an important risk factor for atherosclerotic cardiovascular disease. Nicotinic acid has the uncomfortable but harmless side effect of flush. Prolonged-release nicotinic acid gives rise to less flush than immediate-release nicotinic acid. Treatment with nicotinic acid and statin targets the two independent lipid risk factors of low high-density lipoprotein and high low-density lipoprotein and has clinical benefits in secondary prevention of atherosclerotic cardiovascular disease.