Lipoproteins and cancer: The role of HDL-C, LDL-C, and cholesterol-lowering drugs

Cholesterol is an amphipathic sterol molecule that is vital for maintaining normal physiological homeostasis. It is a relatively complicated molecule with 27 carbons whose synthesis starts with 2-carbon units. This in itself signifies the importance of this molecule. Cholesterol serves as a precursor for vitamin D, bile acids, and hormones, including estrogens, androgens, progestogens, and corticosteroids. Although essential, high cholesterol levels are associated with cardiovascular and kidney diseases and cancer initiation, progression, and metastasis. Although there are some contrary reports, current literature suggests a positive association between serum cholesterol levels and the risk and extent of cancer development. In this review, we first present a brief overview of cholesterol biosynthesis and its transport, then elucidate the role of cholesterol in the progression of some cancers. Suggested mechanisms for cholesterol-mediated cancer progression are plentiful and include the activation of oncogenic signaling pathways and the induction of oxidative stress, among others. The specific roles of the lipoprotein molecules, high-density lipoprotein (HDL) and low-density lipoprotein (LDL), in this pathogenesis, are also reviewed. Finally, we hone on the potential role of some cholesterol-lowering medications in cancer.

Effect of alirocumab on coronary plaque in patients with coronary artery disease assessed by optical coherence tomography

BACKGROUND

Proprotein convertase subtilisin kexin type 9 (PCSK9) inhibitors have been demonstrated to produce significantly greater reduction in LDL cholesterol levels and cardiovascular events than standard statin therapy. However, evidence on the impact of PCSK9 inhibitors on coronary plaque composition and morphology is limited.

METHODS

In this open-label randomized study, eligible patients with intermediate coronary lesions and elevated LDL cholesterol values were randomized to either alirocumab 75 mg Q2W plus statin (atorvastatin 20 mg/day or rosuvastatin 10 mg/day) therapy or standard care. Optical coherence tomography (OCT) assessments for target lesions were obtained at baseline and at 36 weeks of follow-up.

RESULTS

LDL cholesterol levels were significantly decreased in both the alirocumab and standard care arms, whereas the absolute reduction in LDL cholesterol was significantly greater in patients treated with alirocumab (1.72 ± 0.51 vs. 0.96 ± 0.59, P < 0.0001). Compared with standard care, the addition of alirocumab to statins was associated with significantly greater increases in minimum fibrous cap thickness (18.0 [10.8-29.2] μm vs 13.2 [7.4-18.6] μm; P = 0.029), greater increases in minimum lumen area (0.20[0.10-0.33] mm2 vs 0.13 [0.12-0.24] mm2; P = 0.006) and a greater diminution in maximum lipid arc (15.1̊ [7.8-24.5] vs. 8.4̊ [2.0-10.5]; P = 0.008).

CONCLUSIONS

The addition of alirocumab to statins can not only provide additional LDL cholesterol lowering effects but also have a potential role in promoting a more stable plaque phenotype.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT04851769 . Registered 2 Mar 2019.

Pharmacoinformatics and UPLC-QTOF/ESI-MS-Based Phytochemical Screening of Combretum indicum against Oxidative Stress and Alloxan-Induced Diabetes in Long-Evans Rats

This research investigated a UPLC-QTOF/ESI-MS-based phytochemical profiling of Combretum indicum leaf extract (CILEx), and explored its in vitro antioxidant and in vivo antidiabetic effects in a Long-Evans rat model. After a one-week intervention, the animals' blood glucose, lipid profile, and pancreatic architectures were evaluated. UPLC-QTOF/ESI-MS fragmentation of CILEx and its eight docking-guided compounds were further dissected to evaluate their roles using bioinformatics-based network pharmacological tools. Results showed a very promising antioxidative effect of CILEx. Both doses of CILEx were found to significantly (p < 0.05) reduce blood glucose, low-density lipoprotein (LDL), and total cholesterol (TC), and increase high-density lipoprotein (HDL). Pancreatic tissue architectures were much improved compared to the diabetic control group. A computational approach revealed that schizonepetoside E, melianol, leucodelphinidin, and arbutin were highly suitable for further therapeutic assessment. Arbutin, in a Gene Ontology and PPI network study, evolved as the most prospective constituent for 203 target proteins of 48 KEGG pathways regulating immune modulation and insulin secretion to control diabetes. The fragmentation mechanisms of the compounds are consistent with the obtained effects for CILEx. Results show that the natural compounds from CILEx could exert potential antidiabetic effects through in vivo and computational study.

Identification of IgG1 isotype phosphorylcholine antibodies for the treatment of inflammatory cardiovascular diseases

BACKGROUND

Phosphorylcholine (PC) is an important pro-inflammatory damage-associated molecular pattern. Previous data have shown that natural IgM anti-PC protects against cardiovascular disease. We aimed to develop a monoclonal PC IgG antibody with anti-inflammatory and anti-atherosclerotic properties.

METHODS

Using various techniques PC antibodies were validated and optimized. In vivo testing was performed in a femoral artery cuff model in ApoE3*Leiden mice. Safety studies are performed in rats and cynomolgus monkeys.

RESULTS

A chimeric anti-PC (PC-mAb(T15), consisting of a human IgG1 Fc and a mouse T15/E06 Fab) was produced, and this was shown to bind specifically to epitopes in human atherosclerotic tissues. The cuff model results in rapid induction of inflammatory genes and altered expression of genes associated with ER stress and choline metabolism in the lesions. Treatment with PC-mAb(T15) reduced accelerated atherosclerosis via reduced expression of endoplasmic reticulum stress markers and CCL2 production. Recombinant anti-PC Fab fragments were identified by phage display and cloned into fully human IgG1 backbones creating a human monoclonal IgG1 anti-PC (PC-mAbs) that specifically bind PC, apoptotic cells and oxLDL. Based on preventing macrophage oxLDL uptake and CCL2 production, four monoclonal PC-mAbs were selected, which to various extent reduced vascular inflammation and lesion development. Additional optimization and validation of two PC-mAb antibodies resulted in selection of PC-mAb X19-A05, which inhibited accelerated atherosclerosis. Clinical grade production of this antibody (ATH3G10) significantly attenuated vascular inflammation and accelerated atherosclerosis and was tolerated in safety studies in rats and cynomolgus monkeys.

CONCLUSIONS

Chimeric anti-PCs can prevent accelerated atherosclerosis by inhibiting vascular inflammation directly and through reduced macrophage oxLDL uptake resulting in decreased lesions. PC-mAb represents a novel strategy for cardiovascular disease prevention.

PCSK9 Biology and Its Role in Atherothrombosis

It is now about 20 years since the first case of a gain-of-function mutation involving the as-yet-unknown actor in cholesterol homeostasis, proprotein convertase subtilisin/kexin type 9 (PCSK9), was described. It was soon clear that this protein would have been of huge scientific and clinical value as a therapeutic strategy for dyslipidemia and atherosclerosis-associated cardiovascular disease (CVD) management. Indeed, PCSK9 is a serine protease belonging to the proprotein convertase family, mainly produced by the liver, and essential for metabolism of LDL particles by inhibiting LDL receptor (LDLR) recirculation to the cell surface with the consequent upregulation of LDLR-dependent LDL-C levels. Beyond its effects on LDL metabolism, several studies revealed the existence of additional roles of PCSK9 in different stages of atherosclerosis, also for its ability to target other members of the LDLR family. PCSK9 from plasma and vascular cells can contribute to the development of atherosclerotic plaque and thrombosis by promoting platelet activation, leukocyte recruitment and clot formation, also through mechanisms not related to systemic lipid changes. These results further supported the value for the potential cardiovascular benefits of therapies based on PCSK9 inhibition. Actually, the passive immunization with anti-PCSK9 antibodies, evolocumab and alirocumab, is shown to be effective in dramatically reducing the LDL-C levels and attenuating CVD. While monoclonal antibodies sequester circulating PCSK9, inclisiran, a small interfering RNA, is a new drug that inhibits PCSK9 synthesis with the important advantage, compared with PCSK9 mAbs, to preserve its pharmacodynamic effects when administrated every 6 months. Here, we will focus on the major understandings related to PCSK9, from its discovery to its role in lipoprotein metabolism, involvement in atherothrombosis and a brief excursus on approved current therapies used to inhibit its action.

Using genetic variants to evaluate the causal effect of cholesterol lowering on head and neck cancer risk: A Mendelian randomization study

Head and neck squamous cell carcinoma (HNSCC), which includes cancers of the oral cavity and oropharynx, is a cause of substantial global morbidity and mortality. Strategies to reduce disease burden include discovery of novel therapies and repurposing of existing drugs. Statins are commonly prescribed for lowering circulating cholesterol by inhibiting HMG-CoA reductase (HMGCR). Results from some observational studies suggest that statin use may reduce HNSCC risk. We appraised the relationship of genetically-proxied cholesterol-lowering drug targets and other circulating lipid traits with oral (OC) and oropharyngeal (OPC) cancer risk using two-sample Mendelian randomization (MR). For the primary analysis, germline genetic variants in HMGCR, NPC1L1, CETP, PCSK9 and LDLR were used to proxy the effect of low-density lipoprotein cholesterol (LDL-C) lowering therapies. In secondary analyses, variants were used to proxy circulating levels of other lipid traits in a genome-wide association study (GWAS) meta-analysis of 188,578 individuals. Both primary and secondary analyses aimed to estimate the downstream causal effect of cholesterol lowering therapies on OC and OPC risk. The second sample for MR was taken from a GWAS of 6,034 OC and OPC cases and 6,585 controls (GAME-ON). Analyses were replicated in UK Biobank, using 839 OC and OPC cases and 372,016 controls and the results of the GAME-ON and UK Biobank analyses combined in a fixed-effects meta-analysis. We found limited evidence of a causal effect of genetically-proxied LDL-C lowering using HMGCR, NPC1L1, CETP or other circulating lipid traits on either OC or OPC risk. Genetically-proxied PCSK9 inhibition equivalent to a 1 mmol/L (38.7 mg/dL) reduction in LDL-C was associated with an increased risk of OC and OPC combined (OR 1.8 95%CI 1.2, 2.8, p = 9.31 x10-05), with good concordance between GAME-ON and UK Biobank (I2 = 22%). Effects for PCSK9 appeared stronger in relation to OPC (OR 2.6 95%CI 1.4, 4.9) than OC (OR 1.4 95%CI 0.8, 2.4). LDLR variants, resulting in genetically-proxied reduction in LDL-C equivalent to a 1 mmol/L (38.7 mg/dL), reduced the risk of OC and OPC combined (OR 0.7, 95%CI 0.5, 1.0, p = 0.006). A series of pleiotropy-robust and outlier detection methods showed that pleiotropy did not bias our findings. We found limited evidence for a role of cholesterol-lowering in OC and OPC risk, suggesting previous observational results may have been confounded. There was some evidence that genetically-proxied inhibition of PCSK9 increased risk, while lipid-lowering variants in LDLR, reduced risk of combined OC and OPC. This result suggests that the mechanisms of action of PCSK9 on OC and OPC risk may be independent of its cholesterol lowering effects; however, this was not supported uniformly across all sensitivity analyses and further replication of this finding is required.

Cost-Effectiveness of Alirocumab in Patients With Acute Coronary Syndromes: The ODYSSEY OUTCOMES Trial

BACKGROUND

Cholesterol reduction with proprotein convertase subtilisin-kexin type 9 inhibitors reduces ischemic events; however, the cost-effectiveness in statin-treated patients with recent acute coronary syndrome remains uncertain.

OBJECTIVES

This study sought to determine whether further cholesterol reduction with alirocumab would be cost-effective in patients with a recent acute coronary syndrome on optimal statin therapy.

METHODS

A cost-effectiveness model leveraging patient-level data from ODYSSEY OUTCOMES (Evaluation of Cardiovascular Outcomes After an Acute Coronary Syndrome During Treatment With Alirocumab) was developed to estimate costs and outcomes over a lifetime horizon. Patients (n = 18,924) had a recent acute coronary syndrome and were on high-intensity or maximum-tolerated statin therapy, with a baseline low-density lipoprotein cholesterol (LDL-C) level ≥70 mg/dl, non-high-density lipoprotein cholesterol ≥100 mg/dl, or apolipoprotein B ≥80 mg/l. Alirocumab 75 mg or placebo was administered subcutaneously every 2 weeks. Alirocumab was blindly titrated to 150 mg if LDL-C remained ≥50 mg/dl or switched to placebo if 2 consecutive LDL-C levels were <15 mg/dl. Incremental cost per quality-adjusted life-year (QALY) was determined with the addition of alirocumab versus placebo and, based on clinical efficacy findings from the trial, was stratified by baseline LDL-C levels ≥100 mg/dl and <100 mg/dl.

RESULTS

Across the overall population recruited to the ODYSSEY OUTCOMES trial, using an annual treatment cost of US$5,850, the mean overall incremental cost-effectiveness ratio was US$92,200 per QALY (base case). The cost was US$41,800 per QALY in patients with baseline LDL-C ≥100 mg/dl, whereas in those with LDL-C <100 mg/dl the cost per QALY was US$299,400. Among patients with LDL-C ≥100 mg/dl, incremental cost-effectiveness ratios remained below US$100,000 per QALY across a wide variety of sensitivity analyses.

CONCLUSIONS

In patients with a recent acute coronary syndrome on optimal statin therapy, alirocumab improves cardiovascular outcomes at costs considered intermediate value, with good value in patients with baseline LDL-C ≥100 mg/dl but less economic value with LDL-C <100 mg/dl. (Evaluation of Cardiovascular Outcomes After an Acute Coronary Syndrome During Treatment With Alirocumab [ODYSSEY OUTCOMES]; NCT01663402).

Persistent arterial wall inflammation in patients with elevated lipoprotein(a) despite strong low-density lipoprotein cholesterol reduction by proprotein convertase subtilisin/kexin type 9 antibody treatment

AIMS

Subjects with lipoprotein(a) [Lp(a)] elevation have increased arterial wall inflammation and cardiovascular risk. In patients at increased cardiovascular risk, arterial wall inflammation is reduced following lipid-lowering therapy by statin treatment or lipoprotein apheresis. However, it is unknown whether lipid-lowering treatment in elevated Lp(a) subjects alters arterial wall inflammation. We evaluated whether evolocumab, which lowers both low-density lipoprotein cholesterol (LDL-C) and Lp(a), attenuates arterial wall inflammation in patients with elevated Lp(a).

METHODS AND RESULTS

In this multicentre, randomized, double-blind, placebo-controlled study, 129 patients {median [interquartile range (IQR)]: age 60.0 [54.0-67.0] years, Lp(a) 200.0 [155.5-301.5] nmol/L [80.0 (62.5-121.0) mg/dL]; mean [standard deviation (SD)] LDL-C 3.7 [1.0] mmol/L [144.0 (39.7) mg/dL]; National Cholesterol Education Program high risk, 25.6%} were randomized to monthly subcutaneous evolocumab 420 mg or placebo. Compared with placebo, evolocumab reduced LDL-C by 60.7% [95% confidence interval (CI) 65.8-55.5] and Lp(a) by 13.9% (95% CI 19.3-8.5). Among evolocumab-treated patients, the Week 16 mean (SD) LDL-C level was 1.6 (0.7) mmol/L [60.1 (28.1) mg/dL], and the median (IQR) Lp(a) level was 188.0 (140.0-268.0) nmol/L [75.2 (56.0-107.2) mg/dL]. Arterial wall inflammation [most diseased segment target-to-background ratio (MDS TBR)] in the index vessel (left carotid, right carotid, or thoracic aorta) was assessed by 18F-fluoro-deoxyglucose positron-emission tomography/computed tomography. Week 16 index vessel MDS TBR was not significantly altered with evolocumab (-8.3%) vs. placebo (-5.3%) [treatment difference -3.0% (95% CI -7.4% to 1.4%); P = 0.18].

CONCLUSION

Evolocumab treatment in patients with median baseline Lp(a) 200.0 nmol/L led to a large reduction in LDL-C and a small reduction in Lp(a), resulting in persistent elevated Lp(a) levels. The latter may have contributed to the unaltered arterial wall inflammation.

Optimization of Lipid-Lowering Therapy for High Cardiovascular Risk Patients Through Electronic Medical Record Reporting and Pharmacist Evaluation

BACKGROUND

Identification of high cardiovascular risk patients on suboptimal lipid-lowering therapy (LLT) may be possible through electronic medical record (EMR) reporting, presenting an opportunity for pharmacist involvement in optimizing drug regimens.

OBJECTIVES

To (a) identify high cardiovascular risk patients with opportunities for LLT optimization through EMR reporting and (b) evaluate effectiveness of pharmacist review and treatment algorithm on recommending treatment modifications compared with algorithm application alone.

METHODS

We generated an EMR report to identify adult patients aged 21-75 years with clinical atherosclerotic cardiovascular disease and low-density lipoprotein cholesterol (LDL-C) level ≥ 70 mg/dL during a 6-month period and collected pertinent data elements. We selected a subgroup of patients for remote pharmacist review and determined recommendations based on our predefined LLT optimization algorithm and pharmacist clinical judgment. One pharmacist was responsible for making all recommendations and communicated potential treatment modification to primary care providers via email and/or EMR messaging. We tracked provider acceptable/rejection rate to all recommendations made. We also compared recommendations based on using the algorithm alone to combining pharmacist chart review and algorithm and examined reasons for any discrepancies.

RESULTS

941 patients met inclusion criteria, with 399 patients (42.4%) not currently on any LLT. At baseline, 249 patients (25.3%) were on a high-intensity statin, and 19 (1.9%) were on a proprotein convertase subtilisin/kexin type 9 inhibitor. A subgroup of 34 patients were reviewed, of which 30 (88.2%) were on suboptimal therapy despite not achieving LDL-C goals. The pharmacist recommended to intensify statin therapy for 16 patients (47.1%), initiate nonstatin therapy for 9 patients (26.5%), and initiate statin therapy in 5 patients (14.7%). Pharmacist recommendation acceptance rate was 53.3%, with no response received in 26.6% of cases. The algorithm evaluation alone yielded the same recommendation as the combined pharmacist review with algorithm in 30 (88.2%) of the cases and differed in 4 cases.

CONCLUSIONS

The underutilization of LLT among high cardiovascular risk patients remains a growing issue despite effective treatment options with cardiovascular benefits. Pharmacists may be able to identify these patients by using reportable EMR data elements and applying a treatment optimization algorithm to make therapy recommendations and improve outcomes.

DISCLOSURES

This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors. The authors have no relevant declarations of interest to disclose. This study was presented as a poster presentation at the APhA Annual Meeting, March 2019, Seattle, WA, and as a platform presentation at the Eastern States Conference, May 2019, Hershey, PA.

Low-density lipoprotein cholesterol lowering treatment: the current approach

In the last 50 years, several clinical and epidemiological studies during have shown that increased levels of low-density lipoprotein cholesterol (LDLc) are associated with the development and progression of atherosclerotic lesions. The discovery of β-Hydroxy β-methylglutaryl-CoA reductase inhibitors (statins), that possess LDLc-lowering effects, lead to a true revolution in the prevention and treatment of cardiovascular diseases. Statins remain the cornerstone of LDLc-lowering therapy. Lipid-lowering drugs, such as ezetimibe and bile acid sequestrants, are prescribed either in combination with statins or in monotherapy (in the setting of statin intolerance or contraindications to statins). Microsomal triglyceride transfer protein inhibitors and protein convertase subtilisin/kexin type 9 (PCSK9) inhibitors are other drug classes which have been investigated for their potential to decrease LDLc. PCSK9 have been approved for the treatment of hypercholesterolemia and for the secondary prevention of cardiovascular events. The present narrative review discusses the latest (2019) guidelines of the European Atherosclerosis Society/European Society of Cardiology for the management of dyslipidemia, focusing on LDLc-lowering drugs that are either already available on the market or under development. We also consider "whom, when and how" do we treat in terms of LDLc reduction in the daily clinical practice.

Intensive LDL cholesterol-lowering treatment beyond current recommendations for the prevention of major vascular events: a systematic review and meta-analysis of randomised trials including 327 037 participants

BACKGROUND

The benefits of LDL cholesterol-lowering treatment for the prevention of atherosclerotic cardiovascular disease are well established. However, the extent to which these effects differ by baseline LDL cholesterol, atherosclerotic cardiovascular disease risk, and the presence of comorbidities remains uncertain.

METHODS

We did a systematic literature search (MEDLINE, Embase, and the Cochrane Central Register of Controlled Trials, from inception up to June 15, 2019) for randomised controlled trials of statins, ezetimibe, and proprotein convertase subtilisin/kexin type 9 inhibitors with at least 1000 patient-years of follow-up. Random-effects meta-analysis and meta-regressions were done to assess for risk of major vascular events (a composite of cardiovascular mortality, non-fatal myocardial infarction, non-fatal ischaemic stroke, or coronary revascularisation) per 1 mmol/L (38·7 mg/dL) reduction in LDL cholesterol concentrations.

FINDINGS

327 037 patients from 52 studies were included in the meta-analysis. Each 1 mmol/L reduction in LDL cholesterol was associated with a 19% relative risk (RR) reduction for major vascular events (RR 0·81 [95% CI 0·78-0·84]; p<0·0001). Similar reductions (per 1 mmol/L reduction in LDL cholesterol) were found in trials with participants with LDL cholesterol 2·60 mmol/L or lower, 2·61-3·40 mmol/L, 3·41-4·10 mmol/L, and more than 4·1 mmol/L (p=0·232 for interaction); and in a subgroup of patients who all had a baseline LDL cholesterol less than 2·07 mmol/L (80 mg/dL; RR 0·83 [95% CI 0·75-0·92]; p=0·001). We found greater RR reductions in patients at lower 10-year atherosclerotic cardiovascular disease risk (change in RR per 10% lower 10-year atherosclerotic cardiovascular disease 0·97 [95% CI 0·95-0·98]; p<0·0001) and in patients at younger age across a mean age of 50-75 years (change in RR per 10 years younger age 0·92 [0·83-0·97]; p=0·015). We found no difference in RR reduction for participants with or without diabetes (p=0·878 for interaction) and chronic kidney disease (p=0·934 for interaction).

INTERPRETATION

For each 1 mmol/L LDL cholesterol lowering, the risk reduction of major vascular events is independent of the starting LDL cholesterol or the presence of diabetes or chronic kidney disease. Patients at lower cardiovascular risk and younger age might have a similar relative reduction in risk with LDL-cholesterol lowering therapies and future studies should investigate the potential benefits of earlier intervention.

FUNDING

None.

Maximizing the benefits of cholesterol-lowering drugs

PURPOSE OF REVIEW

Drugs to lower LDL-C levels are very widely used. In this brief review, I will use selected recent studies to delineate several important principles that provide a rationale for how to maximize the benefits of using LDL-C lowering drugs to reduce cardiovascular disease. The focus will be on using statins, ezetimibe, and PCSK9 monoclonal antibodies as recent studies have predominantly utilized these agents.

RECENT FINDINGS

The key principles to consider when using LDL-C-lowering drugs to reduce cardiovascular disease are: the lower the LDL-C the better; the sooner and the longer one lowers LDL-C the better; the higher the risk of cardiovascular disease the greater the absolute benefit; the higher the baseline LDL-C the greater the absolute benefit; and compared with the benefits of cholesterol-lowering drugs on reducing cardiovascular disease the risk of side effects is very modest.

SUMMARY

Understanding and employing these key concepts in caring for patients will allow one to use cholesterol-lowering drugs wisely to maximize the reduction of cardiovascular events.

Genetically-predicted life-long lowering of low-density lipoprotein cholesterol is associated with decreased frailty: A Mendelian randomization study in UK biobank

Background

High circulating low-density lipoprotein cholesterol (LDL-C) is a major risk factor for atherosclerosis and age-associated cardiovascular events. Long-term dyslipidaemia could contribute to the development of frailty in older individuals through its role in determining cardiovascular health and potentially other physiological pathways.

Methods

We conducted Mendelian randomization (MR) analyses using genetic variants to estimate the effects of long-term LDL-C modification on frailty in UK Biobank (n = 378,161). Frailty was derived from health questionnaire and interview responses at baseline when participants were aged 40 to 69 years, and calculated using an accumulation-of-deficits approach, i.e. the frailty index (FI). Several aggregated instrumental variables (IVs) using 50 and 274 genetic variants were constructed from independent single-nucleotide polymorphisms (SNPs) to instrument circulating LDL-C concentrations. Specific sets of variants in or near genes that encode six lipid-lowering drug targets (HMGCR, PCSK9, NPC1L1, APOB, APOC3, and LDLR) were used to index effects of exposure to related drug classes on frailty. SNP-LDL-C effects were available from previously published studies. SNP-FI effects were obtained using adjusted linear regression models. Two-sample MR analyses were performed with the IVs as instruments using inverse-variance weighted, MR-Egger, weighted median, and weighted mode methods. To address the stability of the findings, MR analyses were also performed using i) a modified FI excluding the cardiometabolic deficit items and ii) data from comparatively older individuals (aged ≥60 years) only. Several sensitivity analyses were also conducted.

Findings

On average 0.14% to 0.23% and 0.16% to 0.31% decrements in frailty were observed per standard deviation reduction in LDL-C exposure, instrumented by the general IVs consisting of 50 and 274 variants, respectively. Consistent, though less precise, associations were observed in the HMGCR-, APOC3-, NPC1L1-, and LDLR-specific IV analyses. In contrast, results for PCSK9 were in the same direction but more modest, and null for APOB. All sensitivity analyses produced similar findings.

Interpretation

A genetically-predicted life-long lowering of LDL-C is associated with decreased frailty in midlife and older age, representing supportive evidence for LDL-C's role in multiple health- and age-related pathways. The use of lipid-lowering therapeutics with varying mechanisms of action may differ by the extent to which they provide overall health benefits.

Evidence for changing lipid management strategy to focus on non-high density lipoprotein cholesterol

Low-density lipoprotein cholesterol (LDL-C) has been recommended as the primary treatment target on lipid management in coronary heart disease (CHD) patients for past several decades. However, even by aggressive LDL-C lowering treatment, patients still present a significant residual risk of major adverse cardiovascular events (MACE). Non-high-density lipoprotein cholesterol (non-HDL-C) contained all the atherogenic lipoproteins, such as chylomicron, very-low density lipoprotein (VLDL), LDL, intermediate density lipoprotein (IDL). Many prospective observation studies have found that non-HDL-C was better than LDL-C in predicting risks of MACE. Since non-HDL-C appears to be superior for risk prediction beyond LDL-C, current guidelines have emphasize the importance of non-HDL-C for guiding cardiovascular prevention strategies and have flagged non-HDL-C as a co-primary therapeutic target. The goals of non-HDL-C were recommended as 30 mg/dl higher than the corresponding LDL-C goals, but the value seemed inappropriate. This review provide evidence for changing lipid management strategy to focus on non-HDL-C and appropriate values for adding to LDL-C goals would be proposed.

Effect of Alirocumab on Mortality After Acute Coronary Syndromes

Supplemental Digital Content is available in the text.

Background:

Previous trials of PCSK9 (proprotein convertase subtilisin-kexin type 9) inhibitors demonstrated reductions in major adverse cardiovascular events, but not death. We assessed the effects of alirocumab on death after index acute coronary syndrome.

Methods:

ODYSSEY OUTCOMES (Evaluation of Cardiovascular Outcomes After an Acute Coronary Syndrome During Treatment With Alirocumab) was a double-blind, randomized comparison of alirocumab or placebo in 18 924 patients who had an ACS 1 to 12 months previously and elevated atherogenic lipoproteins despite intensive statin therapy. Alirocumab dose was blindly titrated to target achieved low-density lipoprotein cholesterol (LDL-C) between 25 and 50 mg/dL. We examined the effects of treatment on all-cause death and its components, cardiovascular and noncardiovascular death, with log-rank testing. Joint semiparametric models tested associations between nonfatal cardiovascular events and cardiovascular or noncardiovascular death.

Results:

Median follow-up was 2.8 years. Death occurred in 334 (3.5%) and 392 (4.1%) patients, respectively, in the alirocumab and placebo groups (hazard ratio [HR], 0.85; 95% CI, 0.73 to 0.98; P=0.03, nominal P value). This resulted from nonsignificantly fewer cardiovascular (240 [2.5%] vs 271 [2.9%]; HR, 0.88; 95% CI, 0.74 to 1.05; P=0.15) and noncardiovascular (94 [1.0%] vs 121 [1.3%]; HR, 0.77; 95% CI, 0.59 to 1.01; P=0.06) deaths with alirocumab. In a prespecified analysis of 8242 patients eligible for ≥3 years follow-up, alirocumab reduced death (HR, 0.78; 95% CI, 0.65 to 0.94; P=0.01). Patients with nonfatal cardiovascular events were at increased risk for cardiovascular and noncardiovascular deaths (P<0.0001 for the associations). Alirocumab reduced total nonfatal cardiovascular events (P<0.001) and thereby may have attenuated the number of cardiovascular and noncardiovascular deaths. A post hoc analysis found that, compared to patients with lower LDL-C, patients with baseline LDL-C ≥100 mg/dL (2.59 mmol/L) had a greater absolute risk of death and a larger mortality benefit from alirocumab (HR, 0.71; 95% CI, 0.56 to 0.90; P_interaction=0.007). In the alirocumab group, all-cause death declined with achieved LDL-C at 4 months of treatment, to a level of approximately 30 mg/dL (adjusted P=0.017 for linear trend).

Conclusions:

Alirocumab added to intensive statin therapy has the potential to reduce death after acute coronary syndrome, particularly if treatment is maintained for ≥3 years, if baseline LDL-C is ≥100 mg/dL, or if achieved LDL-C is low.

Clinical Trial Registration:

URL: https://www.clinicaltrials.gov. Unique identifier: NCT01663402.

Tackling Residual Atherosclerotic Risk in Statin-Treated Adults: Focus on Emerging Drugs

Epidemiological studies and meta-analyses have consistently suggested the importance of lowering low-density lipoprotein cholesterol (LDL-C) to reduce cardiovascular (CV) events. However, these studies and mechanistic studies using intracoronary imaging modalities have reported patients who continue to experience CV events or disease progression despite optimal LDL-C levels on statins. These findings, including statin intolerance, have highlighted the importance of exploring additional potential therapeutic targets to reduce CV risk. Genomic insights have presented a number of additional novel targets in lipid metabolism. In particular, proprotein convertase subtilisin/kexin type 9 inhibitors have rapidly developed and recently demonstrated their beneficial impact on CV outcomes. Triglyceride (TG)-rich lipoproteins have been recently reported as a causal factor of atherosclerotic cardiovascular disease (ASCVD). Indeed, several promising TG-targeting therapies are being tested at various clinical stages. In this review, we present the evidence to support targeting atherogenic lipoproteins to target residual ASCVD risk in statin-treated patients.

Management of Statin Intolerance in 2018: Still More Questions Than Answers

Statin therapy is generally well tolerated and very effective in the prevention and treatment of cardiovascular disease, regardless of cholesterol levels; however, it can be associated with various adverse events (myalgia, myopathy, rhabdomyolysis, and diabetes mellitus, among others). Patients frequently discontinue statin therapy without medical advice because of perceived side effects and consequently increase their risk for cardiovascular events. In patients with statin intolerance, it may be advisable to change the dose, switch to a different statin, or try an alternate-day regimen. If intolerance is associated with all statins-even at the lowest dose-non-statin drugs and certain nutraceuticals can be considered. This review focuses on the definition of statin intolerance and on the development of clinical and therapeutic strategies for its management, including emerging alternative therapies.

Ethyl pyruvate inhibits oxidation of LDL in vitro and attenuates oxLDL toxicity in EA.hy926 cells

Background

Ethyl pyruvate (EP) exerts anti-inflammatory and anti-oxidative properties. The aim of our study was to investigate whether EP is capable of inhibiting the oxidation of LDL, a crucial step in atherogenesis. Additionally, we examined whether EP attenuates the cytotoxic effects of highly oxidized LDL in the human vascular endothelial cell line EA.hy926.

Methods

Native LDL (nLDL) was oxidized using Cu²⁺ ions in the presence of increasing amounts of EP. The degree of LDL oxidation was quantified by measuring lipid hydroperoxide (LPO) and malondialdehyde (MDA) concentrations, relative electrophoretic mobilities (REMs), and oxidation-specific immune epitopes. The cytotoxicity of these oxLDLs on EA.hy926 cells was assessed by measuring cell viability and superoxide levels. Furthermore, the cytotoxicity of highly oxidized LDL on EA.hy926 cells under increasing concentrations of EP in the media was assessed including measurements of high energy phosphates (ATP).

Results

Oxidation of nLDL using Cu²⁺ ions was remarkably inhibited by EP in a concentration-dependent manner, reflected by decreased levels of LPO, MDA, REM, oxidation-specific epitopes, and diminished cytotoxicity of the obtained oxLDLs in EA.hy926 cells. Furthermore, the cytotoxicity of highly oxidized LDL on EA.hy926 cells was remarkably attenuated by EP added to the media in a concentration-dependent manner reflected by a decrease in superoxide and an increase in viability and ATP levels.

Conclusions

EP has the potential for an anti-atherosclerotic drug by attenuating both, the oxidation of LDL and the cytotoxic effect of (already formed) oxLDL in EA.hy926 cells. Chronic administration of EP might be beneficial to impede the development of atherosclerotic lesions.

Protective and therapeutic effects of Crataegus aronia in non-alcoholic fatty liver disease

AIM

We evaluated the potential preventive and therapeutic effects of Crataegus aronia (C. aronia) in NAFLD induced by high-fat diet (HFD) in rat models.

METHODS

Protective effect of Crataegus aronia or simvastatin was investigated in Wistar rats fed either low-fat diet (LFD) or HFD.

RESULTS

Liver histopathological examinations confirmed the development of NAFLD in rats fed HFD. In both protective and therapeutic treatments, C. aronia significantly reduced liver index (3.85 ± 0.21% in HFD plus aronia group versus 6.22 ± 0.58% in HFD model group), increased the HDL-cholesterol and reduced the LDL-cholesterol in blood. The hawthorn plant also significantly ameliorated oxidative stress biomarker (p < 0.002) and liver enzymes (p < 0.0001) that indicate liver damage.

CONCLUSION

C. aronia exhibits therapeutic and protective effects on NAFLD in an animal model possibly by its lipid lowering and antioxidant effects; thus, may offer therapeutic potential in humans.

Evolocumab (Repatha)--a second PCSK9 inhibitor to lower LDL-Cholesterol

The second FDA-approved PCSK9 inhibitor evolocumab (Repatha) appears to be similar in efficacy and safety to alirocumab (Praluent), but no comparative studies are available. Given by subcutaneous injection every 2 weeks or once monthly, evolocumab can further lower LDL-cholesterol levels by about 60% in patients at high risk for atherosclerotic cardiovascular disease already taking maximal statin therapy. Its effect on cardiovascular outcomes remains to be established. The long-term efficacy and safety of both evolocumab and alirocumab are unknown, and they are expensive.

Effect of Ezetimibe on LDL-C Lowering and Atherogenic Lipoprotein Profiles in Type 2 Diabetic Patients Poorly Controlled by Statins

Background

There exists a subpopulation of T2DM in whom first-line doses of statin are insufficient for optimally reducing LDL-C, representing a major risk of CVD. The RESEARCH study focuses on LDL-C reduction in this population along with modifications of the lipid profiles leading to residual risks.

Methods

Lipid changes were assessed in a randomized, multicenter, 12-week, open-label study comparing a high-potency statin (10mg of atorvastatin or 1mg of pitavastatin) plus ezetimibe (EAT: n = 53) with a double dose of statin (20mg of atorvastatin or 2mg of pitavastatin) (DST: n = 56) in DM subjects who had failed to achieve the optimal LDL-C targets. Lipid variables were compared with a primary focus on LDL-C and with secondary focuses on the percentage of patients who reached the LDL-C targets and changes in the levels of RLP-C (remnant like particle cholesterol) and sd-LDL-C, two characteristic atherogenic risks of DM.

Results

The reduction of LDL-C (%), the primary endpoint, differed significantly between the two groups (-24.6 in EAT vs. -10.9 in DST). In the analyses of the secondary endpoints, EAT treatment brought about significantly larger reductions in sd-LDL-C (-20.5 vs. -3.7) and RLP-C (-19.7 vs. +5.5). In total, 89.4% of the patients receiving EAT reached the optimized treatment goal compared to 51.0% of the patients receiving DST. The changes in TC (-16.3 vs. -6.3) and non-HDL-C (-20.7 vs. -8.3) differed significantly between the two groups.

Conclusion

Ezetimibe added to high-potency statin (10 mg of atorvastatin or 1 mg of pitavastatin) was more effective than the intensified-dose statin (20 mg of atorvastatin or 2 mg of pitavastatin) treatment not only in helping T2DM patients attain more LDL-C reduction, but also in improving their atherogenic lipid profiles, including their levels of sd-LDL-C and RLP-C.

We thus recommend the addition of ezetimibe to high-potency statin as a first line strategy for T2DM patients with insufficient statin response.

Trial Registration

The UMIN Clinical Trials Registry UMIN000002593

Pharmacogenomics of statin therapy: any new insights in efficacy or safety?

PURPOSE OF REVIEW

To examine the current evidence concerning the effects of genetic variation on statin-related low-density lipoprotein cholesterol reductions, clinical efficacy, and adverse events and the relevance for patient care.

RECENT FINDINGS

Recent years have seen the emergence of large-scale genetic experiments, including genome-wide association studies and candidate gene studies, exploring the impact of common genetic variation on patient response to statins. These studies have built on previous smaller scale evidence, providing improved statistical power and enhanced ability to explore the genome. Current evidence suggests that common genetic variants do not alter low-density lipoprotein cholesterol response by more than a few percent, or materially alter the effect of statin on vascular risk reduction, and therefore that patients benefit from statins independent of common genetic variation. However, knowledge of SLCO1B1 genotypes is believed to have clinical utility for predicting myopathy risk and ensuring that statins are prescribed as safely as possible. Furthermore, new hypothesis-generating studies, such as those associating GATM with myopathy risk, offer potential insights for the future.

SUMMARY

Common genetic variation does not appear to be an important determinant of statin response, with the exception of SLCO1B1 and risk of myopathy. Future studies will help to determine the impact of low-frequency and rare genetic variation on statin response.

Targeting LDL: is lower better and is it safe?

Low density lipoprotein cholesterol (LDL-C) is one of the most validated targets in clinical medicine. Large randomized, outcome trials have demonstrated a clear relationship between reducing LDL-C and cardiovascular disease (CVD) risk, which has been maintained to LDL-C levels of <1.8 mmol/L. To assess the benefit of even lower LDL-C it is important to recognize that CVD risk reduction is related to absolute reduction in LDL-C, not to percent change. Furthermore measurement of LDL-C is also critical as recent studies show the Friedewald calculation significantly underestimates true LDL-C values <1.8 mmol/L, distorting the relationship with CVD risk reduction. Discussion of potential harm from low, or lower, LDL-C has centered on cancer, hemorrhagic stroke, and violent death, but there is little evidence from outcome trials to show a relationship with low LDL-C. Proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitors which will reduce LDL-C well below 1.3 mmol/L, will likely provide the clearest answer to both the question of efficacy and safety of low LDL-C within the next few years.

PCSK9 inhibitors

PURPOSE OF REVIEW

To summarize the therapeutic strategies to inhibit PCSK9 and to describe the main results obtained in phase I and II trials with monoclonal antibodies targeting PCSK9.

RECENT FINDINGS

Among the various approaches for PCSK9 inhibition, human data are only available for inhibition of PCSK9 binding to LDL receptor by monoclonal antibodies. Promising preclinical studies have also been reported with other strategies, including inhibition of PCSK9 synthesis by gene silencing agents. The two most advanced monoclonal antibodies in development are SAR236553/REGN727 and AMG145. In phase II, these two monoclonal antibodies administered subcutaneously are well tolerated and effective to decrease atherogenic lipoproteins. A dramatic decrease in LDL cholesterol up to 70% can be obtained. The efficacy has been evaluated so far in addition to statins in hypercholesterolemic patients with or without familial hypercholesterolemia, in patients with intolerance to statin therapy and in monotherapy.

SUMMARY

The short-term efficacy, safety and tolerability of two monoclonal antibodies to PSCK9 have been demonstrated in several phase II trials. These PCSK9 inhibitors are now tested in larger phase III studies to provide insights into the long-term safety and clinical efficacy of this very promising approach.

Recent advances in niacin and lipid metabolism

PURPOSE OF REVIEW

This review focuses on the current understanding of the physiological mechanisms of action of niacin on lipid metabolism and atherosclerosis.

RECENT FINDINGS

Emerging findings indicate that niacin decreases hepatic triglyceride synthesis and subsequent VLDL/LDL secretion by directly and noncompetitively inhibiting hepatocyte diacylglycerol acyltransferase 2. Recent studies in mice lacking niacin receptor GPR109A and human clinical trials with GPR109A agonists disproved the long believed hypothesis of adipocyte triglyceride lipolysis as the mechanism for niacin's effect on serum lipids. Niacin, through inhibiting hepatocyte surface expression of β-chain ATP synthase, inhibits the removal of HDL-apolipoprotein (apo) AI resulting in increased apoAI-containing HDL particles. Additional recent findings suggest that niacin by increasing hepatic ATP-binding cassette transporter A1-mediated apoAI lipidation increases HDL biogenesis, thus stabilizing circulation of newly secreted apoAI. New concepts have also emerged on lipid-independent actions of niacin on vascular endothelial oxidative and inflammatory events, myeloperoxidase release from neutrophils and its impact on HDL function, and GPR109A-mediated macrophage inflammatory events involved in atherosclerosis.

SUMMARY

Recent advances have provided physiological mechanisms of action of niacin on lipid metabolism and atherosclerosis. Better understanding of niacin's actions on multiple tissues and targets may be helpful in designing combination therapy and new treatment strategies for atherosclerosis.

Microsomal transfer protein inhibition in humans

PURPOSE OF REVIEW

Microsomal triglyceride transfer protein (MTP) is a key protein in the secretion of apolipoprotein B-containing lipoproteins. Its pharmacological inhibition is associated with a decrease in LDL cholesterol (LDL-C) and triglycerides. However, the clinical use of MTP inhibitors has been uncertain because of the gastrointestinal adverse events and the increase in liver fat content observed during their administration.

RECENT FINDINGS

Lomitapide, a systemic MTP inhibitor, significantly reduces LDL-C in homozygous familial hypercholesterolemia (hoFH) when administered concurrently with other lipid-lowering therapies, including apheresis. Its lipid-lowering effect is additive to that of existing drugs. In the presence of an up-titration regiment and low-fat diet, lomitapide is generally well tolerated and liver fat accumulation stabilizes after the initial increase. Elevation of alanine aminotranferase levels greater than 3 times the upper limit of normal can be managed successfully with temporary dose reduction. Drug-drug interaction studies show that concomitant treatment of lomitapide with other lipid-lowering drugs is generally safe. Based on these findings, lomitapide was recently approved for the treatment of hoFH as add-on therapy.

SUMMARY

MTP inhibition is a valuable therapeutic approach for hoFH. Long-term safety consequences of liver fat accumulation will need to be assessed.

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.

Effects of cholesteryl ester transfer protein inhibitors on human lipoprotein metabolism: why have they failed in lowering coronary heart disease risk?

PURPOSE OF REVIEW

To examine the recent advances in our knowledge of cholesteryl ester transfer protein (CETP) inhibitors, heart disease risk reduction, and human lipoprotein metabolism.

RECENT FINDINGS

CETP inhibitors block the transfer of cholesteryl ester from HDLs to triglyceride-rich lipoproteins (TRLs), thereby raising HDL cholesterol and lowering TRL cholesterol, and in some cases LDL cholesterol. Two CETP inhibitors, dalcetrapib and torcetrapib, have been tested in large clinical trials in statin-treated coronary heart disease patients and have shown no clinical benefit compared to placebo. Anacetrapib and evacetrapib, two potent CETP inhibitors, are now being tested in large clinical trials. Torcetrapib has been shown to decrease the fractional catabolic rate (FCR) of HDL apolipoproteins (apo) A-I and A-II, enhance the FCR of TRL apoB-100 and apoE, and decrease TRL apoB-48 production, but has no significant effects on fecal cholesterol excretion in humans. Anacetrapib also delays the FCR of HDL apoA-I.

SUMMARY

CETP inhibitors form a complex between themselves, CETP, and HDL particles, which may interfere with the many physiologic functions of HDL, including reverse cholesterol transport. Available data would suggest that CETP inhibitors will fail as lipid-altering medications to reduce coronary heart disease risk because of interference with normal human HDL metabolism.

[Binding of human serum low-density lipoprotein cholesterol in vitro by sulfated pectin derivatives]

The ability to bind human serum LDL-C in vitro by the native pectins is lower than that of their sulfation derivatives. The number of sulfate groups and molecular weight of the sulfated derivatives are assumed to be crucial factors. The sulfated derivatives of pectin with molecular weight above 200 kDa containing 45 wt % sulfate groups possess the highest ability to bind atherogenic lipids, the lowest activity was estimated for the derivatives with molecular weight below 50 kDa containing 5 wt % of sulfate groups.

Meta-analysis of the cardiovascular benefits of intensive lipid lowering with statins

OBJECTIVE

To evaluate the efficacy of intensive lipid lowering with higher-dose statins.

METHODS

Meta-analysis of seven randomized controlled trials comprising 50,972 participants.

RESULTS

Mean follow-up was 3.1 years with mean age 63 years. Final LDL-C levels in intensive lipid-lowering group were 1.42-2.07 mmol/l compared to 2.1-3.5 mmol/l in the less intensive or control group. The intensive arm had significantly lower risks for stroke OR 0.80 (95% CI 0.71-0.89); major coronary events OR 0.74 (95% CI 0.65-0.83); cardiovascular disease (CVD) or coronary heart disease (CHD) deaths OR 0.84 (95% CI 0.74-0.95). Significantly higher liver enzyme abnormalities occurred in intensive group* (OR 3.96; 95% CI 2.08-7.53), but it was not associated with drug discontinuations (OR 1.20; 95% CI 0.88-1.64).

CONCLUSION

In those at high risk of cardiovascular events, intensive lipid lowering with statins to LDL-C level <2.1 mmol/l significantly reduces risk of stroke, major coronary events and CVD or CHD deaths compared to LDL-C level ≥ 2.1 mmol/l. [*Correction added on 11 January 2011 after first online publication on 27 October 2010. The phrase, "Significantly higher liver enzyme abnormalities occurred in less intensive group", was amended to "Significantly higher liver enzyme abnormalities occurred in intensive group".].

Cholesterol absorption and synthesis markers in individuals with and without a CHD event during pravastatin therapy: insights from the PROSPER trial

Cholesterol homeostasis, defined as the balance between absorption and synthesis, influences circulating cholesterol concentrations and subsequent coronary heart disease (CHD) risk. Statin therapy targets the rate-limiting enzyme in cholesterol biosynthesis and is efficacious in lowering CHD events and mortality. Nonetheless, CHD events still occur in some treated patients. To address differences in outcome during pravastatin therapy (40 mg/day), plasma markers of cholesterol synthesis (desmosterol, lathosterol) and fractional cholesterol absorption (campesterol, sitosterol) were measured, baseline and on treatment, in the Prospective Study of Pravastatin in the Elderly at Risk trial participants with (cases, n = 223) and without (controls, n = 257) a CHD event. Pravastatin therapy decreased plasma LDL-cholesterol and triglycerides and increased HDL-cholesterol concentrations to a similar extent in cases and controls. Decreased concentrations of the cholesterol synthesis markers desmosterol (-12% and -11%) and lathosterol (-50% and -56%) and increased concentrations of the cholesterol absorption markers campesterol (48% and 51%) and sitosterol (25% and 26%) were observed on treatment, but the magnitude of change was similar between cases and controls. These data suggest that decreases in cholesterol synthesis in response to pravastatin treatment were accompanied by modest compensatory increases in fractional cholesterol absorption. The magnitude of these alterations were similar between cases and controls and do not explain differences in outcomes with pravastatin treatment.

Other therapies for reducing low-density lipoprotein cholesterol: medications in development

Although the past 30 years have been fruitful and productive in lipid research, from basic science to drug development to demonstration of clinical benefit, cardiovascular disease remains the major cause of mortality and morbidity in industrialized societies. With the rapid industrialization of countries, such as India and China, cardiovascular disease rapidly is becoming the leading cause of global death and disability. Although most of the effective lipid-lowering drugs, the statins, have become generic and inexpensive, there remains a need for effective and safe agents. Hopefully, some of those discussed in this article will fill that need.

The crystal structure of PCSK9: a regulator of plasma LDL-cholesterol

Proprotein convertase subtilisin kexin type 9 (PCSK9) has been shown to be involved in the regulation of extracellular levels of the low-density lipoprotien receptor (LDLR). Although PCSK9 is a subtilase, it has not been shown to degrade the LDLR, and its LDLR-lowering mechanism remains uncertain. Here we report the crystal structure of human PCSK9 at 2.3 A resolution. PCSK9 has subtilisin-like pro- and catalytic domains, and the stable interaction between these domains prevents access to PCSK9's catalytic site. The C-terminal domain of PCSK9 has a novel protein fold and may mediate protein-protein interactions. The structure of PCSK9 provides insight into its biochemical characteristics and biological function.

Identifying and Attaining LDL-C Goals: Mission Accomplished? Next Target: New Therapeutic Options to Raise HDL-C Levels

Currently, low density lipoprotein cholesterol (LDL-C) levels are the main, if not the only, lipid target in the effort to reduce cardiovascular disease (CVD) morbidity and mortality. Several primary and secondary CVD prevention trials with statins shaped current guidelines and provided detailed targets across a range of CVD risk categories. These targets can be attained using effective statins or combination therapy. However, the net benefit in CVD risk reduction may be improved if we address other lipid risk factors. High density lipoprotein cholesterol (HDL-C) emerges from epidemiological studies as the most promising target. This review links the increase in HDL-C levels with clinical benefit from "old" (e.g. sustained release niacin) and new treatment options. Synthetically produced recombined apolipoprotein A-I Milano administered intravenously seems to have a marked effect in reducing the atheroma burden. The anti-cholesterol ester transfer protein (CETP) vaccine (CETi-1) produces auto-antibodies against CETP thus increasing the cholesterol ester content in HDL particles. CETP inhibitors (e.g. JTT-705 and torcetrapib) seem to be the most promising regimen to increase HDL-C levels. Torcetrapib (already in phase IIIa studies) can substantially increase HDL-C levels (up to 106%), alone or in combination with atorvastatin. HDL-C strategies, in combination with effective statins, are a new drug target aimed at a further reduction in CVD morbidity and mortality compared with statin monotherapy.

NPC1L1: Evolution From Pharmacological Target to Physiological Sterol Transporter

Niemann-Pick C1-like 1 protein (NPC1L1) was recently shown to be the molecular target of the cholesterol absorption inhibitor class of drugs, of which ezetimibe is the first widely used member. Since its discovery, NPC1L1 has also been shown to play a focal physiological role in intestinal absorption of sterols, including plant sterols and cholesterol. Evidence in support of this new metabolic pathway has been garnered not only through human, animal, and cell studies of function but also through the use of human genetics as an approach to study the association of NPC1L1 sequence variation with metabolic and drug-response phenotypes. The example of NPC1L1 shows how the elucidation of a pharmacological target can serve as a means to gain understanding of a key physiological pathway.

Mechanisms by which dietary fatty acids modulate plasma lipids

Dietary fatty acids have a considerable effect on plasma LDL cholesterol (LDL-C) concentrations and therefore on the risk for coronary heart disease. Numerous studies have been conducted in animal models to elucidate the mechanisms by which different types of fatty acids modulate plasma cholesterol concentrations. In addition, multiple clinical trials and epidemiological data have demonstrated the effects of fatty acids in determining the concentrations of circulating LDL. SFAs and trans fatty acids have a detrimental effect on plasma lipids, whereas PUFAs of the (n-6) family and monounsaturated fatty acids decrease plasma LDL-C concentrations. Among the SFAs, stearic acid (18:0) appears to have a neutral effect on LDL-C, while lauric (12:0), myristic (14:0), and palmitic (16:0) acids are considered to be hypercholesterolemic. SFAs increase plasma LDL-C by increasing the formation of LDL in the plasma compartment and by decreasing LDL turnover. Although unsaturated fatty acids increase cholesterol synthesis, they also increase hepatic LDL receptor number and LDL turnover in vivo. Fatty acids are also ligands of important regulatory elements, which can play a role in determining plasma cholesterol. This article presents a summary of the major effects of various types of fatty acids on plasma lipid concentrations and the mechanisms involved.

Apolipoproteins C-II and C-III inhibit selective uptake of low- and high-density lipoprotein cholesteryl esters in HepG2 cells

Plasma low- and high-density lipoproteins (LDL and HDL) are cleared from the circulation by specific receptors and are either totally degraded or their cholesteryl esters (CE) are selectively delivered to cells by receptors such as the scavenger receptor class B type I (SR-BI). The aim of the present study was to define the effect of apoC-II and apoC-III on the uptake of LDL and HDL by HepG2 cells. Stable transformants were obtained with sense or antisense strategies that secrete 47-294% the normal level of apoC-II or 60-200% that of apoC-III. Different levels of secreted apoC-II or apoC-III had little effect on LDL and HDL protein degradation by HepG2 cells. However, compared to controls, cells under-expressing apoC-II showed a 160% higher capacity to selectively take up HDL-CE, while cells under-expressing apoC-III demonstrated 70 and 160% higher capacity to take up CE from LDL and HDL, respectively. In experiments conducted with exogenously added apoC-II or apoC-III, no significant effect was observed on lipoprotein-protein association/degradation; however, LDL-CE and HDL-CE selective uptake was significantly reduced in a dose-dependent manner. These results indicate that apoC-II and apoC-III inhibit CE-selective uptake.

The beneficial effects of lipid-lowering drugs beyond lipid-lowering effects: a comparative study with pravastatin, atorvastatin, and fenofibrate in patients with type IIa and type IIb hyperlipidemia

Hyperlipidemia is an important risk factor for atherosclerosis. Hemorheological factors contribute to morbidity and mortality in patients with dyslipidemia. We evaluated the effects of 3 antihyperlipidemic drugs (pravastatin, atorvastatin, and fenofibrate), which have different mechanisms of action and different patterns of action on lipid profiles, on erythrocyte deformability and fibrinogen levels in patients with type IIa and type IIb hyperlipidemia. Twenty-one patients ( 4 men and 17 women) with type IIa and IIb hyperlipidemia were randomized to 3 drugs (pravastatin 20 mg/d, atorvastatin 10 mg/d, fenofibrate 250 mg/d) for 8 weeks. Plasma glucose, total cholesterol, triglyceride, high-density lipoprotein cholesterol (HDL-C), and low-density lipoprotein cholesterol (LDL-C) analysis were performed on a BM-Hitachi 747-200 autoanalyzer (Hitachi-Roche, Tokyo, Japan). Fibrinogen analysis was performed according to Clauss method. Erythrocyte deformability was assessed with cell transit analysis device. There was no significant difference in body mass index, lipid profile, fibrinogen level, and erythrocyte deformability index values among the groups before treatment ( P > .05). In all groups, there were statistically significant reductions in total LDL-C levels ( P < .05). The triglyceride levels were significantly reduced in the atorvastatin and fenofibrate groups ( P < .05), but not in the pravastatin group ( P > .05). There was no significant change in HDL-C levels during the treatment with statins ( P > .05), but there was a significant increase in the fenofibrate group ( P < .05). Mean erythrocyte deformability index was improved in all the groups ( P < .05). There was no significant change in fibrinogen levels during the treatment of pravastatin and atorvastatin ( P > .05), but in fenofibrate group, fibrinogen levels were significantly decreased ( P < .05). The 3 groups of antihyperlipidemic drugs have beneficial effects on the erythrocyte deformability index. Only fenofibrate has significant beneficial effects on the fibrinogen levels.

Peripheral Arterial Disease: A Missed Opportunity to Administer Statins so as to Reduce Cardiac Morbidity and Mortality

Peripheral arterial disease (PAD) is a common condition associated with an increased risk of coronary heart disease, myocardial infarction and stroke. It follows that PAD merits aggressive preventive treatment that includes lipid lowering drugs (mainly statins). This review summarises the current knowledge concerning the use and mechanisms of action of statins in patients with PAD. Statins not only lower the risk of vascular events, but they also improve the symptoms associated with PAD. There is also evidence that statins reduce surgical mortality and improve graft patency and limb salvage. Because of the high risk, a more aggressive goal [i.e. low density lipoprotein cholesterol (LDL-C) of 70 mg/dl; 1.8 mmol/l] [National Cholesterol Education Program (NCEP) Adult Treatment Panel III (ATP III), revised guidelines 2004] should be considered to maximally reduce the atheroma burden and related events. Not all statins can achieve this LDL-C target. Furthermore, there may be a need to use an additional lipid lowering drug so as to achieve the LDL-C goal and benefit from the different modes of action. Statins exert beneficial pleiotropic effects on haemostasis, the vasculature and inflammatory markers. There is also evidence that statins improve renal function (the plasma creatinine level is considered as an emerging vascular risk factor). Since PAD patients often take several drugs, there is a need to carefully consider their selection so as to maximize benefits and minimize adverse effects. Patients with PAD often do not receive adequate lipid lowering treatment. This situation needs to change.

HMR 3339, a novel selective estrogen receptor modulator, reduces total cholesterol, low-density lipoprotein cholesterol, and homocysteine in healthy postmenopausal women

OBJECTIVE

To investigate the short-term effects of HMR 3339 in comparison with raloxifene and placebo on cardiovascular risk factors.

DESIGN

A multicenter, randomized, placebo-controlled, double-blind, dose-ranging study.

SETTING

Gynecologic outpatient department.

PATIENT(S)

One hundred eighteen healthy nonhysterectomized postmenopausal women.

INTERVENTION(S)

Participants received daily placebo (n = 22), 2.5 mg of HMR 3339 (n = 25), 10 mg of HMR 3339 (n = 24), 50 mg of HMR 3339 (n = 24), or 60 mg of raloxifene (n = 23) for 12 weeks followed by a 2-week washout period.

MAIN OUTCOME MEASURE(S)

Blood concentrations of lipids measured at baseline, and after 2, 4, 8, 12, and 14 weeks, and of lipoprotein(a), homocysteine, and endothelin-1 measured at baseline, and after 4 and 12 weeks.

RESULT(S)

After 12 weeks of treatment with HMR 3339, compared with placebo, serum total cholesterol was reduced (10 mg of HMR 3339: -9.7%; 50 mg of HMR 3339: -15.2%), low-density lipoprotein (LDL)-cholesterol (10 mg of HMR 3339: -10.8%; 50 mg of HMR 3339: -24.2%) and plasma homocysteine concentrations (2.5 mg of HMR 3339: -3.9%; 10 mg of HMR 3339: -10.8%; 50 mg of HMR 3339: -13.8%), suggesting a dose-dependent effect of HMR 3339. These effects were already apparent after 2 weeks of treatment for total cholesterol and LDL-cholesterol, and after 4 weeks of treatment for homocysteine. After 12 weeks, raloxifene, compared with placebo, significantly decreased total cholesterol (-10.5%), LDL-cholesterol (-15.0%), and triglycerides (-16.9%), but not homocysteine. High-density lipoprotein-cholesterol, lipoprotein(a), and endothelin-1 showed no significant changes in any of the active treatment groups.

CONCLUSION(S)

HMR 3339 reduces total cholesterol, LDL-cholesterol, and homocysteine concentrations in postmenopausal women.

Lipid-altering agents: the future

Lipid-lowering is established as proven intervention to reduce atherosclerosis and its complications. This article summarises novel developments in the lipid-altering therapies under development. It also discusses other therapeutic targets, such as squalene synthase, microsomal transfer protein, acyl-cholesterol acyl transferase, cholesterol ester transfer protein, peroxosimal proliferator-activating receptors and lipoprotein (a), for which compounds have been developed and have at least reached trials in animal models. Lipid-altering drugs are likely to prove a fast-developing area for novel treatments, as possible synergies exist between new and established compounds for the treatment of atherosclerosis.

Antioxidant activity of peptides derived from egg white proteins by enzymatic hydrolysis

This work reports the antioxidant activity of peptides produced by enzymatic hydrolysis of crude egg white with pepsin. Four peptides included in the protein sequence of ovalbumin possessed radical scavenging activity higher than that of Trolox. The hydrolysate of egg white with pepsin for 3 h was previously found to exhibit a strong angiotensin I-converting enzyme (ACE) inhibitory activity in vitro. The combined antioxidant and ACE inhibition properties make it a very useful multifunctional preparation for the control of cardiovascular diseases, particularly hypertension. No correlation was found between antioxidant and ACE inhibitory activities. However, the peptide Tyr-Ala-Glu-Glu-Arg-Tyr-Pro-Ile-Leu, which was a strong ACE inhibitor (50% inhibitory concentration, 4.7 microM) also exhibited a high radical scavenging activity (oxygen radical absorbance capacity-fluorescein value, 3.8 micromol of Trolox equivalent per micromol of peptide) and delayed the low-density lipoprotein lipid oxidation induced by Cu2+ at a concentration of approximately 0.16 mg/mg of low-density lipoprotein. Present results support that antioxidant peptides and amino acids not only act individually, but also cooperatively and synergistically.

PPARalpha activation abolishes LDL-stimulated IL-8 production via AP-1 deactivation in human aortic smooth muscle cells

Native low density lipoprotein (n-LDL) is a major risk factor for cardiovascular diseases by inducing inflammatory processes and vascular smooth muscle cell proliferation in vessel cells. It has previously been reported that LDL enhances inflammatory reactions by the up-regulation of interleukin (IL)-8 via the activation of p38 kinase and activator protein (AP)-1 in human aortic smooth muscle cells (hAoSMCs). The findings of this study show, for the first time, that the peroxisome proliferator-activated receptor (PPARalpha) agonist, fenofibrate, completely abolishes the LDL-induced IL-8 up-regulation at the transcriptional level. Pretreatment of hAoSMCs with fenofibrate abolishes the effects of LDL on AP-1 activation without affecting nuclear factor (NF)-kappaB. In contrast, fenofibrate failed to modulate the activation state of p38 and JNK kinases or the levels of c-fos and phospho-Jun. These data suggest that AP-1 is likely to be located at the crossroads between LDL signaling and the regulation of IL-8 modulation by PPARalpha.

Simulating titration to goal clinical trials with statins

Many countries have local guidelines on the management of subjects' lipid levels with and without pharmaceutical intervention. The statin class of drugs is the preferred class for reducing low density lipoprotein cholesterol (LDL-C). Different statins have different potencies and different dose ranges. It is of interest to simulate clinical trials in which subjects are titrated through the dose ranges of various statins in accordance with local guidelines, in order to estimate the proportion of subjects who reach treatment goal of LDL-C at any particular dose of any particular statin.

Effect of a new beta-sitosterol analogue on plasma lipid concentrations in rats

N-Substituted succinamic acid beta-sitosteryl ester derivatives were prepared and evaluated. Compounds 1 and 2 were prepared in 76-92% yields by the reaction of beta-sitosterol and succinic anhydride, followed by the activation of the resulting acid compound 1 by thionyl chloride or methyl chloroformate, and finally by amination with appropriate amines. Compound 2a (DANA87) was also easily obtained in one step by the direct addition of beta-sitosterol to dicyclohexylcarbodiimide (DCC) in 80% yield. Administration of the dietary compound DANA87 resulted in significant decreases in total plasma cholesterol (TC) and low-density lipoprotein (LDL) cholesterol concentrations compared with controls in a rat model. High-density lipoprotein cholesterol and plasma triglyceride levels were not affected. These findings indicate that DANA87 functions as TC and LDL cholesterol-reducing agent.