Perspectives in cholesterol-lowering therapy: the role of ezetimibe, a new selective inhibitor of intestinal cholesterol absorption

Research trends in lipid-lowering therapies for coronary heart disease combined with hyperlipidemia: a bibliometric study and visual analysis

Background

Cardiovascular disease (CVD) poses a significant global health and economic challenge, with atherosclerosis being a primary cause. Over the past 40 years, substantial research has been conducted into the prevention and reversal of atherosclerosis, resulting in the development of lipid-lowering agents such as statins and fibrates. Despite the extensive literature and formulation of numerous therapeutic guidelines in this domain, a comprehensive bibliometric analysis of the current research landscape and trends has not been performed. This study aimed to elucidate the evolution and milestones of research into lipid-lowering treatments for coronary heart disease (CHD) in conjunction with hyperlipidemia through bibliometric analysis, offering insights into future directions for treatment strategies.

Methods

This study examined publications from 1986 to 2023 retrieved from the Web of Science database (Core Collection). Utilizing tools such as VOSviewer, Pajek, and CiteSpace, we analyzed publication and citation numbers, H-indexes, contributions by countries and institutions, authorship, journal sources, and keyword usage to uncover research trajectories and areas of focus.

Results

Our analysis of 587 publications revealed a recent surge in research output, particularly post-2003. The American Journal of Cardiology published the highest number of studies, with 40 articles, whereas Circulation received the highest number of citations (6,266). Key contributors included the United States, Japan, and China, with the United States leading in citation numbers and the H-index. Harvard University and Leiden University emerged as pivotal institutions, and Professors J. Wouter Jukema and Robert P. Giugliano were identified as leading experts. Keyword analysis disclosed five thematic clusters, indicating a shift in research towards new drug combinations and strategies, signaling future research directions.

Conclusion

The last 4 decades have seen a notable rise in publications on lipid-lowering therapies for CHD and hyperlipidemia, with the United States retaining world-leading status. The increase in international collaboration aids the shift towards research into innovative lipid-lowering agents and therapeutic approaches. PCSK9 inhibitors and innovative combination therapies, including antisense oligonucleotides and angiopoietin-like protein 3 inhibitors, provide avenues for future research, intending to maximize the safety and efficacy of treatment approaches.

Treatment of Ezetimibe lowers total and low-density lipoprotein cholesterol in hypercholesterolemic dogs with hyperadorenocorticism

Ezetimibe is a cholesterol absorption inhibitor that blocks the intestinal absorption of both biliary and dietary cholesterol, thereby lowering primarily low density lipoprotein-cholesterol (LDL-chol) in human studies. This study aimed to investigate the effects of ezetimibe on dyslipidemia control in nine dogs with hypercholesterolemia. Changes in total cholesterol (T-chol) and each lipoprotein fractions were evaluated at 0, 2, and 4 months following initiation of ezetimibe treatment. A significant decrease in T-chol was observed, and a mean T-chol concentration below 400 mg/dL was achieved at 2 and 4 months. Furthermore, a significant decrease in LDL-chol was observed (-53.3% and -64.3% at 2 and 4 months, respectively). Taken together, treatment of ezetimibe could lower LDL-chol levels in dogs with hypercholesterolemia.

Metabolic dysfunction associated steatotic liver disease: Current practice, screening guidelines and management in the primary care setting

Metabolic dysfunction associated steatotic liver disease, previously known as non-alcoholic fatty liver disease, is the most common cause of chronic liver disease in the United States with rapidly rising prevalence. There have been significant changes recently in the field with screening now recommended for patients at risk for significant liver fibrosis in primary care and endocrine settings, along with clear guidance for management of metabolic comorbidities and changes in nomenclature. This paper serves as a summary of recent guidance for the primary care physician focusing on identifying appropriate patients for screening, selecting suitable screening modalities, and determining when referral to specialty care is necessary. The hope is that providers will shift away from past practices of utilizing liver tests alone as a screening tool and shift towards fibrosis screening in patients at risk for significant fibrosis. This culture change will allow for earlier identification of patients at risk for end stage liver disease and serious liver related complications, and overall improved patient care.

Current Medical Therapy and Revascularization in Peripheral Artery Disease of the Lower Limbs: Impacts on Subclinical Chronic Inflammation

Peripheral artery disease (PAD), coronary artery disease (CAD), and cerebrovascular disease (CeVD) are characterized by atherosclerosis and inflammation as their underlying mechanisms. This paper aims to conduct a literature review on pharmacotherapy for PAD, specifically focusing on how different drug classes target pro-inflammatory pathways. The goal is to enhance the choice of therapeutic plans by considering their impact on the chronic subclinical inflammation that is associated with PAD development and progression. We conducted a comprehensive review of currently published original articles, narratives, systematic reviews, and meta-analyses. The aim was to explore the relationship between PAD and inflammation and evaluate the influence of current pharmacological and nonpharmacological interventions on the underlying chronic subclinical inflammation. Our findings indicate that the existing treatments have added anti-inflammatory properties that can potentially delay or prevent PAD progression and improve outcomes, independent of their effects on traditional risk factors. Although inflammation-targeted therapy in PAD shows promising potential, its benefits have not been definitively proven yet. However, it is crucial not to overlook the pleiotropic properties of the currently available treatments, as they may provide valuable insights for therapeutic strategies. Further studies focusing on the anti-inflammatory and immunomodulatory effects of these treatments could enhance our understanding of the mechanisms contributing to the residual risk in PAD and pave the way for the development of novel therapies.

Bempedoic Acid: Lipid Lowering for Cardiovascular Disease Prevention

The management of low-density lipoprotein cholesterol (LDL-C) levels is a central strategy for the prevention of atherosclerotic cardiovascular disease. Current United States (2018 American Heart Association/American College of Cardiology/Multisociety) and European (2019 European Society of Cardiology/European Atherosclerosis Society) guidelines endorse statin therapy as the first-line therapy for pharmacologic LDL-C lowering. However, in clinical practice up to 30% of patients report partial or complete intolerance to statin therapy. While the nocebo effect with statins is well described, perceived statin intolerance prevents many patients from achieving LDL-C thresholds associated with clinical benefit. Bempedoic acid is a novel, oral, non-statin lipid-l owering therapy that works by inhibiting adenosine triphosphate-citrate lyase, an enzymatic reaction upstream of 3-hydroxy-3-methylglutaryl coenzyme A reductase in the hepatic cholesterol synthesis pathway. Bempedoic acid confers reduction in LDL-C of ~18% on background statin therapy,~21% in patients with statin intolerance, and ~38% when given in fixed-dose combination with ezetimibe. The CLEAR Outcomes trial, which enrolled high-risk primary and secondary prevention patients with reported statin intolerance and LDL-C levels ≥100 mg/dL, showed that bempedoic acid compared with placebo reduced 4-component major adverse cardiovascular events (MACE) by 13% (hazard ratio 0.87, 95% confidence interval 0.79-0.96). Bempedoic acid also reduced 3-component MACE by 15%, myocardial infarction by 23% and coronary revascularization by 19%. The benefit was even greater in the primary prevention cohort (hazard ratio 0.70, 95% confidence interval 0.55-0.89) for 4-component MACE. Bempedoic acid was associated with increases in uric acid levels and cholelithiasis, but numerically fewer events of myalgia and new-onset diabetes. These findings confirm that bempedoic acid is an effective approach to reduce cardiovascular outcomes in high-risk patients with statin intolerance who require further reduction in LDL-C.

Microbial oil, alone or paired with β-glucans, can control hypercholesterolemia in a zebrafish model

Dyslipidemia is often associated with unhealthy dietary habits, and many mammalian studies have explored the mode of action of certain bioactive compounds such as β-glucans and n-3 PUFAs to understand their potential to normalize the lipid metabolism. There are only a few investigations that adopted omic approaches to unveil their combined effect on hypercholesterolemia. Zebrafish (Danio rerio) was used as a model organism to reveal the efficacy of Schizochytrium oil and β-glucans (from Euglena gracilis and Phaeodactylum tricornutum) against cholesterol-rich diet induced dyslipidemia. One of the folowing four diets was fed to a particular group of fish: a control high-cholesterol diet, a Schizochytrium oil diet or one of the two diets containing the oil and β-glucan. The plasma HDL, expression of hepatic genes linked to, among others, ferric ion binding and plasma phosphatidylcholines were higher and plasma cholesterol esters and triacylglycerols were lower in the microbial oil-fed fish compared to the fish fed high cholesterol diet. While the fish fed a mix of microbial oil and Euglena β-glucan had lower plasma triacylglycerols and expression of hepatic genes linked to PPAR signaling pathway and enriched biosynthesis of plasma unsaturated fatty acids, the fish fed microbial oil-Phaeodactylum β-glucan combination had lower abundance of triacylglycerols rich in saturated and mono-unsaturated fatty acids and cholesterol esters in the plasma.

Current and future options in cholesterol lowering treatments

The relative risk reduction of cardiovascular events is proportional to the absolute reduction in LDL-C levels, the primary target of therapy, no matter the way of reduction. During the last decades, the therapeutic regimens for reducing the LDL-C levels have been immerged and improved, with favorable effects on the atherosclerotic process and clinical benefits of various cardiovascular outcomes. From a practical view of point, this review is focusing only on the current available lipid lowering agents: statins, ezetimibe, anti PCSK9 monoclonal antibodies, the small interfering RNA (siRNA) agent, Inclisiran, and Bempedoic acid. The recent changes in lipid lowering regimens, including the early combination of lipid lowering agents and "Low LDL-C" levels <30 mg/dL for high/very high cardiovascular risk patients will also be discussed.

UV-visible absorption spectroscopy for in-line API concentration measurement in nanoparticle production process using controlled expansion of supercritical solutions (CESS®)

Most new small drug molecules in pharmaceutical development require improvement of solubility. The controlled expansion of supercritical solutions (CESS®) process is a nanoparticle production technology, dedicated to enhancing the dissolution rate of active pharmaceutical ingredients (APIs) suffering from poor solubility and enabling novel drug delivery opportunities. In this process, the API is dissolved in supercritical carbon dioxide (scCO₂) and nanoparticles are formed through controlled pressure reduction. To improve process visibility and control, ultraviolet-visible (UV-Vis) spectroscopy was incorporated into CESS® process as a process analytical technology (PAT) tool. The tool quantifies the amount of API dissolved in scCO₂ during the solubilization phase of the process. Sample interfacing of the UV-Vis spectrometer was done with a custom-made pressure and temperature rated transmission flow-through cell. In-process calibration was developed to correlate the UV-Vis absorption spectra to the API concentration. Due to the density-dependent molar absorption coefficient of API in scCO₂, the calibration was done for each combination of temperature and pressure. The developed PAT tool provides insight into the process enabling real-time API quantity estimation. It also facilitates process development through Quality by Design (QbD) and offers a system for enhanced process control and troubleshooting. For instance, the in-line API concentration data allows one to study the solubilization behavior of the API in the process and to optimize the process parameters in order to maximize throughput.

Bioactivity of Dietary Polyphenols: The Role in LDL-C Lowering

Cardiovascular diseases are the leading causes of the death around the world. An elevation of the low-density lipoprotein cholesterol (LDL-C) level is one of the most important risk factors for cardiovascular diseases. To achieve optimal plasma LDL-C levels, clinal therapies were investigated which targeted different metabolism pathways. However, some therapies also caused various adverse effects. Thus, there is a need for new treatment options and/or combination therapies to inhibit the LDL-C level. Dietary polyphenols have received much attention in the prevention of cardiovascular diseases due to their potential LDL-C lowering effects. However, the effectiveness and potential mechanisms of polyphenols in lowering LDL-C is not comprehensively summarized. This review focused on dietary polyphenols that could reduce LDL-C and their mechanisms of action. This review also discussed the limitations and suggestions regarding previous studies.

Cholesterol-Lowering Drugs on Akt Signaling for Prevention of Tumorigenesis

Cholesterol has been reported to be accumulated in cancer cells. The metabolic dysregulation of the cholesterol is associated with tumor development and progression. The cholesterol-lowering drugs have been found to be involved in the prevention and treatment of various cancers. Akt, a serine/threonine kinase, can modulate the role of several downstream proteins involved in cell proliferation, migration, invasion, metabolism, and apoptosis. Since its involvement in several signaling pathways, its dysregulation is commonly reported in several cancers. Thus, targeting Akt could be an effective approach for cancer prevention and therapy. Cholesterol-lowering drugs have been found to affect the expression of Akt, and its activation in the cancer cells and thus have shown anticancer activity in different type of cancers. These drugs act on various signaling pathways such as PTEN/Akt, PI3k/Akt, Akt/NF-κB, Akt/FOXO1, Akt/mTOR, etc., which will be discussed in this article. This review article will discuss the significance of cholesterol in cancer cells, cholesterol-lowering drugs, the role of Akt in cancer cells, and the effects of cholesterol-lowering drugs on Akt in the prevention of therapy resistance and metastasis.

Goal achievement of HbA1c and LDL-cholesterol in a randomized trial comparing colesevelam with ezetimibe: GOAL-RCT

AIM

To compare the efficacy and safety of colesevelam and ezetimibe as second-line low density lipoprotein-cholesterol (LDL-c)-lowering options in type 2 diabetes (T2D).

MATERIALS AND METHODS

GOAL-RCT is a 24-week, open-label, randomized, pragmatic clinical trial. Subjects with T2D with uncontrolled HbA1c (7.1%-10%) and LDL-c (>2.0 mmol/L) were randomized 1:1 to colesevelam 3.75 g or ezetimibe 10 mg daily. The primary composite outcome was the proportion of participants achieving an LDL-c target of ≤2.0 mmol/L and HbA1c target of ≤7.0%. Intention to treat analysis was performed.

RESULTS

Two hundred subjects were enrolled: mean age 59 ± 10 years; mean HbA1c 8.0%; mean LDL-c 2.5 mmol/L; 97% on statin therapy. The primary composite outcome was achieved by similar proportions of participants with colesevelam (14.6%) and ezetimibe (10.5%) (P_{non-inferiority}  < .001, P_superiority = .41). LDL-c reduction from baseline was less with colesevelam compared with ezetimibe (14.0% vs. 23.2%, P < .01), as was the proportion of subjects achieving an LDL-c target of ≤2.0 mmol/L (47.6% and 67.0%, respectively; P = .007). Mean HbA1c was reduced with colesevelam (-0.26 ± 0.10%), while no change was observed with ezetimibe (difference P = .06). Adverse events and discontinuation rates were higher for colesevelam (20.2% and 31.1%) compared with ezetimibe (7.2% and 6.2%), respectively.

CONCLUSIONS

Among subjects with T2D, the initiation of colesevelam or ezetimibe led to similar achievement of primary composite outcome (LDL-c and HbA1c within target), with ezetimibe recording a greater LDL-c reduction and better tolerability than colesevelam.

A Brief Review of Cardiovascular Diseases, Associated Risk Factors and Current Treatment Regimes

Cardiovascular diseases (CVDs) are the leading cause of premature death and disability in humans and their incidence is on the rise globally. Given their substantial contribution towards the escalating costs of health care, CVDs also generate a high socio-economic burden in the general population. The underlying pathogenesis and progression associated with nearly all CVDs are predominantly of atherosclerotic origin that leads to the development of coronary artery disease, cerebrovascular disease, venous thromboembolism and, peripheral vascular disease, subsequently causing myocardial infarction, cardiac arrhythmias or stroke. The aetiological risk factors leading to the onset of CVDs are well recognized and include hyperlipidaemia, hypertension, diabetes, obesity, smoking and, lack of physical activity. They collectively represent more than 90% of the CVD risks in all epidemiological studies. Despite high fatality rate of CVDs, the identification and careful prevention of the underlying risk factors can significantly reduce the global epidemic of CVDs. Beside making favorable lifestyle modifications, primary regimes for the prevention and treatment of CVDs include lipid-lowering drugs, antihypertensives, antiplatelet and anticoagulation therapies. Despite their effectiveness, significant gaps in the treatment of CVDs remain. In this review, we discuss the epidemiology and pathology of the major CVDs that are prevalent globally. We also determine the contribution of well-recognized risk factors towards the development of CVDs and the prevention strategies. In the end, therapies for the control and treatment of CVDs are discussed.

Biocatalysis as Useful Tool in Asymmetric Synthesis: An Assessment of Recently Granted Patents (2014–2019)

The broad interdisciplinary nature of biocatalysis fosters innovation, as different technical fields are interconnected and synergized. A way to depict that innovation is by conducting a survey on patent activities. This paper analyses the intellectual property activities of the last five years (2014–2019) with a specific focus on biocatalysis applied to asymmetric synthesis. Furthermore, to reflect the inventive and innovative steps, only patents that were granted during that period are considered. Patent searches using several keywords (e.g., enzyme names) have been conducted by using several patent engine servers (e.g., Espacenet, SciFinder, Google Patents), with focus on granted patents during the period 2014–2019. Around 200 granted patents have been identified, covering all enzyme types. The inventive pattern focuses on the protection of novel protein sequences, as well as on new substrates. In some other cases, combined processes, multi-step enzymatic reactions, as well as process conditions are the innovative basis. Both industries and academic groups are active in patenting. As a conclusion of this survey, we can assert that biocatalysis is increasingly recognized as a useful tool for asymmetric synthesis and being considered as an innovative option to build IP and protect synthetic routes.

Lipid-lowering effects of Coffea arabica pulp aqueous extract in Caco-2 cells and hypercholesterolemic rats

BACKGROUND

Coffea arabica pulp (CP) is the first by-product obtained from coffee berries during coffee processing. The major constituents of CP, including chlorogenic acid, caffeine, and epicatechin exhibit anti-hyperlipidemic effects in in vitro and in vivo models. Whether Coffea arabica pulp aqueous extract (CPE) has a lipid-lowering effect remains unknown.

PURPOSE

This study examined the effect of CPE on cholesterol absorption, and identified the mechanisms involved in lowered cholesterol in in vitro and in vivo models.

METHODS

Uptake of [³H]-cholesterol micelles and the mode of CPE inhibition were determined using human intestinal Caco-2 cells, and subsequently, confirmed using isolated rat jejunal loops. In addition, the 12-week high-fat diet-induced hypercholesterolemic rats (HF) received either CPE (1000  mg/kg BW), a sole and high dose which was selected because it contained approximately 12  mg of CGA that was previously shown to have lipid-lowering effects, or ezetimibe (10  mg/kg BW), a cholesterol inhibitor. The rats were divided into HF, HF  ++ CPE, and HF  ++ ezetimibe groups for the next 12 weeks. Normal rats received a normal diet (ND) and CPE (ND  +  CPE). Body weights and lipid profiles were evaluated. Cholesterol transporter, Niemann-Pick C1-Like 1 (NPC1L1), protein expression and liver X receptor alpha (LXRα) mRNA expression were determined. In vitro micellar complex properties were also investigated.

RESULTS

CPE inhibited [³H]-cholesterol micelle transport in Caco-2 cells and rat jejunal loops in a dose-dependent, non-competitive manner partly by decreasing membrane NPC1L1 expression. Congruently, CPE and its major constituents activated LXRα which, in turn, down-regulated NPC1L1. Furthermore, CPE interfered with physicochemical characteristics of cholesterol mixed micelles. These data were consistent with decreased body weight and slowed body weight gain and improved lipid profiles by CPE in hypercholesterolemic rats while no change occurred in these parameters in normal rats. Down-regulated intestinal NPC1L1 expression mediated by increased LXRα mRNA were also observed in HF  ++ CPE and ND  +  CPE rats.

CONCLUSION

CPE has a cholesterol-lowering effect in in vitro and in vivo via inhibition of intestinal cholesterol absorption by down-regulating NPC1L1 mediated LXRα activation and interfering with micellar complex formation. Accordingly, CPE could be developed as nutraceutical product to prevent dyslipidemia-induced obesity and insulin resistance.

Ezetimibe prescriptions in older Canadian adults after an acute myocardial infarction: a population-based cohort study

Background

The utility of ezetimibe in preventing cardiovascular outcomes remains controversial. To guide future assessments of the effectiveness of ezetimibe in routine care, we evaluated how this medication has been prescribed to high-risk older adults in Ontario, Canada.

Methods

Using linked healthcare databases, we carried out a population-based cohort study of older adults who were discharged from hospital following an acute myocardial infarction from 2005 until 2014. We ascertained the rate of ezetimibe initiation within 6 months of their discharge. We also examined the characteristics of new ezetimibe prescriptions, as well as the predictors for receiving the therapy.

Results

Seventy one thousand one hundred twenty five older adults were hospitalized for an acute myocardial infarction between 2005 and 2014 (mean age 78.36 ± 7.71 years, 45.8% women). Only 1230 (1.7%) patients were newly prescribed ezetimibe within 6 months of their hospital discharge. The median duration of continuous use of ezetimibe was 1.2 years (IQR 0.3–3.5 years). Ezetimibe was prescribed more often to patients living in rural areas, with a history of coronary artery disease, on high-potency statins, and, with evidence of healthcare follow-up after hospital discharge. Prescriptions were less common in men, older patients, those living in long-term care facilities, those with a history of congestive heart failure, and those who were hospitalized for a myocardial infarction in more recent years.

Conclusions

Real-world drug effectiveness studies can help to complement the findings of randomized controlled trials. In our region however, only a small proportion of high-risk older adults received a prescription for ezetimibe following a myocardial infarction. Clinical and research implications are discussed.

Electronic supplementary material

The online version of this article (10.1186/s12944-017-0649-5) contains supplementary material, which is available to authorized users.

Ezetimibe Use and LDL-C Goal Achievement: A Retrospective Database Analysis of Patients with Clinical Atherosclerotic Cardiovascular Disease or Probable Heterozygous Familial Hypercholesterolemia

BACKGROUND

Ezetimibe is recommended by clinical practice guidelines as a second-line therapy for lowering low-density lipoprotein cholesterol (LDL-C) levels, but little is known about its use and effectiveness in real-world populations.

OBJECTIVE

To understand the real-world impact of adding or switching to ezetimibe on LDL-C goal achievement in patients with clinical atherosclerotic cardiovascular disease (ASCVD) and/or heterozygous familial hypercholesterolemia (HeFH).

METHODS

Patients aged ≥ 18 years with an LDL-C measurement available between January 1, 2013, and June 30, 2014, were identified using the Inovalon MORE ² database; this included commercial, health insurance exchange, Medicare Advantage, and managed Medicaid patients. The index date was the date of the first LDL-C measurement. Patients were required to have evidence of clinical ASCVD or probable HeFH based on ICD-9-CM codes and ≥ 1 outpatient pharmacy claim for a statin in the 1-year pre-index period, as well as continuous medical and pharmacy coverage for 1 year pre- and post-index. Patients who added ezetimibe to existing statin therapy or switched to ezetimibe within 90 days post-index LDL-C measurement were identified in order to replicate the typical time a clinician takes to assess the use of ezetimibe. The primary outcome was the proportion of patients who met the LDL-C goal of < 70 mg/dL within the follow-up period. LDL-C goal achievement was evaluated by baseline LDL-C level groupings: < 70 mg/dL, 70-99 mg/dL, 100-129 mg/dL, or ≥ 130 mg/dL; and across 4 patient diagnosis categories: all patients, ASCVD only, probable HeFH only, and ASCVD and probable HeFH. Descriptive analyses were reported. Categorical variables were summarized as the number of and corresponding percentage of patients. Continuous variables were presented as the mean and SD of the number of observations and median and range where appropriate.

RESULTS

Of 125,330 patients who met selection criteria, mean age was 70.1 (SD = 9.9) years and mean LDL-C baseline was 90.7 (SD = 34.0) mg/dL. Over one half of patients (70%) were receiving statin therapy. Within the post-index time frame, 1.05% (n = 1,309) of patients added or switched to ezetimibe. Of these, 26% achieved LDL-C goal during the 90-day follow-up (59.5% did not achieve goal and 14.4% did not have a follow-up lab value). Therapeutic targets were reached by 30% of patients with baseline LDL-C levels of 70-99 mg/dL; 14% of those with baseline LDL-C of 100-129 mg/dL; and 7% of those with baseline LDL-C of ≥ 130 mg/dL. Achievement of LDL-C goals also varied by baseline diagnosis category.

CONCLUSIONS

The addition of or switch to ezetimibe therapy was associated with a relatively small percentage of LDL-C goal achievement (< 70 mg/dL) in patients with clinical ASCVD and/or HeFH, even among patients with baseline LDL-C between 70 and 99 mg/dL. To provide superior individualized care for patients with hyperlipidemia, there is a potential role for newer therapies in lipid lowering, such as PCSK9 inhibitors, in appropriate high-risk populations.

DISCLOSURES

This study was sponsored by Amgen. Menzin, Yu, and Stern are employees of Boston Health Economics, which was contracted by Amgen to perform this study. Aggarwal is a former employee of Boston Health Economics. Boatman, Patel, and Harrison are employees and stockholders of Amgen. Study concept and design were contributed by Menzin, Aggarwal, Harrison, and Patel. Aggarwal, Stern, and Yu collected the data. Data interpretation was performed by Aggarwal, Harrison, Patel, and Boatman. The manuscript was written and revised primarily by Aggarwal, with assistance from the other authors.

Antilipidemic Drug Therapy Today and in the Future

The armamentarium for the treatment of dyslipidemia today comprises six different modes of action with overall around 24 different drugs. The treatment of lipid disorders was revolutionized with the introduction of statins which have become the most important therapeutic option available today to reduce and prevent atherosclerosis and its detrimental consequences like cardiovascular diseases and stroke. With and optimized reduction of elevated LDL levels with statins, the risk for cardiovascular diseases (CVD) can be reduced by 30%, indicating a residual remaining risk of 70% for the development and progression of CVD notifying still a high medical need for more effective antilipidemic drugs. Consequently, the search for novel lipid-modifying drugs is still one of the most active areas in research and development in the pharmaceutical industry. Major focus lies on approaches to LDL-lowering drugs superior to statins with regard to efficacy, safety, and patient compliance and on approaches modifying plasma levels and functionality of HDL particles based on the clinically validated inverse relationship between high-plasma HDL levels and the risk for CVD. The available drugs today for the treatment of dyslipidemia are small organic molecules or nonabsorbable polymers for binding of bile acids to be applied orally. Besides small molecules for novel targets, biological drugs such as monoclonal antibodies, antisense or gene-silencing oligonucleotides, peptidomimetics, reconstituted synthetic HDL particles and therapeutic proteins are novel approaches in clinical development are which have to be applied by injection or infusion. The promising clinical results of several novel drug candidates, particularly for LDL cholesterol lowering with monoclonal antibodies raised against PCSK9, may indicate more than a decade after the statins, the entrance of new breakthrough therapies to treat lipid disorders.

Preparation and characterization of amorphous ezetimibe nanosuspensions intended for enhancement of oral bioavailability

Objective:

The objective of this study was to prepare and investigate better and stable amorphous ezetimibe nanosuspensions for oral bioavailability enhancement.

Materials and Methods:

Nanosuspensions of ezetimibe were prepared by solvent-antisolvent precipitation technique using the surfactant, Tween 80 as stabilizer. The nanosuspension preparation was optimized for particle size by investigating two factors that is, solvent:antisolvent ratio and surfactant concentration, at three levels. The formulations were characterized for particle size, surface morphology, crystallinity, zeta potential, saturation solubility, in vitro drug release and in vivo drug absorption.

Results:

The nanosuspensions of ezetimibe were successfully prepared using solvent-antisolvent precipitation. The two factors solvent:antisolvent ratio and surfactant concentration influenced the particle size of the nanosuspensions prepared. Nanosuspensions were smooth and spherical. The X-ray powdered diffraction and differential scanning calorimetry results indicated that the antisolvent-solvent method led to the amorphization of ezetimibe. Under storage, the amorphous ezetimibe nanosuspensions demonstrated significant physical stability. Ezetimibe nanosuspensions increased the saturation solubility to an extent of 4-times. Ezetimibe nanosuspensions completely dissolved in the dissolution medium within 1 h, while pure drug was dissolved up to 42% during same time. The C_max with ezetimibe nanosuspension was approximately 3-fold higher when compared with that of ezetimibe conventional suspensions administered orally.

Conclusions:

Stable amorphous ezetimibe nanosuspensions were successfully prepared and these nanosuspensions demonstrated dramatic improvement in oral bioavailability of the active.

Impact of drug policy on regional trends in ezetimibe use

BACKGROUND

Ezetimibe use has steadily increased in Canada during the past decade even in the absence of evidence demonstrating a beneficial effect on clinical outcomes. Among the 4 most populated provinces in Canada, there is a gradient in the restrictiveness of ezetimibe in public-funded formularies (most to least strict: British Columbia, Alberta, Quebec, and Ontario). The effect of formulary policy on the use of ezetimibe over time is unknown.

METHODS AND RESULTS

We conducted a population-level cohort study using Intercontinental Marketing Services Health Canada's data from June 2003 to December 2012 to examine ezetimibe use in these 4 provinces to better understand the association between use and formulary restrictiveness. We found regional variations in the patterns of ezetimibe use. From June 2003 to December 2012, British Columbia (most restrictive) had the lowest monthly increasing rate from $261 to $21 926 ($190/100 000 population/mo), whereas Ontario (least restrictive) had the most rapid monthly increase from $223 to $74 030 ($ 647/100 000 population/mo), and Quebec from $130 to $59 690 ($522/100 000 population/mo) and Alberta from $356 to $ 37 604 ($327/100 000 population/mo) were intermediate (P<0.001).

CONCLUSIONS

Ezetimibe use remains common, increasing during the past decade. Use steadily increased in provinces with the most lenient formularies. In contrast, use was lower, plateauing since 2008 in British Columbia and Alberta, which have more restrictive formularies. The gradient in ezetimibe use was related to variability in restrictiveness of the provincial formularies, illustrating the potential of a policy response gradient that may be used to more effectively manage medication use.

Impact of the ENHANCE trial on the use of ezetimibe in the United States and Canada

BACKGROUND

We previously found that the use of ezetimibe increased rapidly with different patterns between the United States (US) and Canada prior to the landmark Ezetimibe and Simvastatin in Hypercholesterolemia Enhance Atherosclerosis Regression (ENHANCE) trial, which was reported in January 2008, and failed to show that the drug slowed the progression of atherosclerosis. What is not known is how practice in the 2 countries changed after the ENHANCE trial. We examined ezetimibe use trends in the US and Canada before and after the reporting of the ENHANCE trial.

METHODS

We conducted a population-based, retrospective, time-series analysis using the data collected by IMS Health in the US and CompuScript in Canada from January 1, 2002, to December 31, 2009. The main outcome measure was monthly number of prescriptions for ezetimibe-containing products.

RESULTS

The monthly number of ezetimibe prescriptions/100,000 population rose from 6 to 1,082 in the US from November 2002 to January 2008, then significantly declined to 572/100,000 population by December 2009 after the release of the ENHANCE trial, a decrease of 47.1% (P < .001). In contrast, in Canada, use continuously rose from 2 to 495/100,000 population from June 2003 to December 2009 (P = .2). United States expenditures totaled $2.24 billion in 2009.

CONCLUSIONS

Ezetimibe remains commonly used in both the US and Canada. Ezetimibe use has decreased in the US post-ENHANCE, whereas use has gradually but steadily increased in Canada. The diverging patterns of ezetimibe use in the US and Canada require further investigation, as they reveal that a common evidence base is eliciting very different utilization patterns in neighboring countries.

Phytosterols protect against diet-induced hypertriglyceridemia in Syrian golden hamsters

BACKGROUND

In addition to lowering LDL-C, emerging data suggests that phytosterols (PS) may reduce blood triglycerides (TG), however, the underlying mechanisms are not known.

METHODS

We examined the TG-lowering mechanisms of dietary PS in Syrian golden hamsters randomly assigned to a high fat (HF) diet or the HF diet supplemented with PS (2%) for 6 weeks (n = 12/group). An additional subset of animals (n = 12) was provided the HF diet supplemented with ezetimibe (EZ, 0.002%) as a positive control as it is a cholesterol-lowering agent with known TG-lowering properties.

RESULTS

In confirmation of diet formulation and compound delivery, both the PS and EZ treatments lowered (p < 0.05) intestinal cholesterol absorption (24 and 31%, respectively), blood non-HDL cholesterol (61 and 66%, respectively), and hepatic cholesterol (45 and 55%, respectively) compared with the HF-fed animals. Blood TG concentrations were lower (p < 0.05) in the PS (49%) and EZ (68%)-treated animals compared with the HF group. The TG-lowering response in the PS-supplemented group was associated with reduced (p < 0.05) intestinal SREBP1c mRNA (0.45 fold of HF), hepatic PPARα mRNA (0.73 fold of HF), hepatic FAS protein abundance (0.68 fold of HD), and de novo lipogenesis (44%) compared with the HF group. Similarly, lipogenesis was lower in the EZ-treated animals, albeit through a reduction in the hepatic protein abundance of ACC (0.47 fold of HF).

CONCLUSIONS

Study results suggest that dietary PS are protective against diet-induced hypertriglyceridemia, likely through multiple mechanisms that involve modulation of intestinal fatty acid metabolism and a reduction in hepatic lipogenesis.

Efficacy and safety of rosuvastatin in late-onset hypogonadism patients with dyslipidaemia

Rosuvastatin has been used for treatment of dyslipidaemia and metabolic syndrome, but the efficacy has not yet been tested in men with late-onset hypogonadism (LOH). To assess and compare the efficacy and safety of rosuvastatin in men with dyslipidaemia with LOH and non-LOH, a retrospective study was conducted in patients who received rosuvastatin 10 mg day(-1) from the men's health clinic. The primary endpoint was the change in low-density lipoprotein (LDL)-cholesterol (C) after 24 weeks of treatment. A total of 145 dyslipidaemic patients eligible for rosuvastatin treatment were enrolled and divided into LOH group (45.52%) and non-LOH (54.48%) group. There were favourable changes in the lipid profiles. In the LOH group whose serum testosterone had been raised by testosterone administration, the favourable changes of the lipids were of similar magnitude as in the non-LOH group. The percentage of patients reaching the target goal (LDL < 100 mg dL(-1) ) did not differ significantly between the group of non-LOH and LOH men treated with testosterone. Side effects were noted in 1/145 men. It is concluded that rosuvastatin was safe and effective in lowering low-density lipoprotein cholesterol in both non-LOH and LOH dyslipidaemic patients whose serum testosterone levels had normalised.

A Randomized Trial Assessing the Effectiveness of Ezetimibe in South Asian Canadians with Coronary Artery Disease or Diabetes: The INFINITY Study

Background. There is a paucity of data regarding the effectiveness and safety of lipid-lowering treatments among South-Asian patients. Methods. Sixty-four South-Asian Canadians with coronary artery disease or diabetes and persistent hypercholesterolemia on statin therapy, were randomized to ezetimibe 10 mg/day co-administered with statin therapy (EZE + Statin) or doubling their current statin dose (STAT²). Primary outcome was the proportion of patients achieving target LDL-C (<2.0 mmol/L) after 6 weeks. Secondary outcomes included the change in lipid profile and the incidence of treatment-emergent adverse events through 12 weeks. Exploratory markers for vascular inflammation were assessed at baseline and 12 weeks. Results. At 6 weeks, the primary outcome was significantly higher among the EZE + Statin patients (68% versus 36%; P = 0.031) with an OR (95% CI) of 3.97 (1.19, 13.18) upon accounting for baseline LDL-C and adjusting for age. At 12 weeks, 76% of EZE + Statin patients achieved target LDL-C compared to 48% (P = 0.047) of the STAT² patients (adjusted OR (95% CI) = 3.31 (1.01,10.89)). No significant between-group differences in exploratory markers were observed with the exception of CRP. Conclusions. Patients receiving ezetimibe and statin were more likely to achieve target LDL-C after 6 and 12 weeks compared to patients doubling their statin dose. Ezetimibe/statin combination therapy was well tolerated among this cohort of South-Asian Canadians, without safety concerns.

Cyanidin-3-O-β-glucoside upregulates hepatic cholesterol 7α-hydroxylase expression and reduces hypercholesterolemia in mice

SCOPE

Although previous studies have shown that consumption of anthocyanin extract from plant foods reduces hypercholesterolemia and the severity of atherosclerosis in different animal models, the mechanisms of these actions remained unclear. This study investigated whether pure anthocyanin inhibit atherosclerosis development and reduce hypercholesterolemia in the apolipoprotein E (ApoE)-deficient mice through enhancement of fecal bile acid excretion, a critical pathway for eliminating circulation cholesterol from the body.

METHODS AND RESULTS

Five-week-old male ApoE-deficient mice were fed the AIN-93G diet supplemented with or without cyanidin-3-O-β-glucoside (0.06% w/w) for 12 weeks. Results showed that cyanidin-3-O-β-glucoside consumption inhibited the formation of aortic sinus plaque and reduced hypercholesterolemia, along with promoted fecal bile acid excretion and upregulated hepatic cholesterol 7a-hydroxylase expression (CYP7A1). In mouse primary hepatocytes, cyanidin-3-O-β-glucoside treatment increased bile acid synthesis and CYP7A1 expression in a liver X receptor alpha (LXRα)-)-dependent manner. Scintillation proximity and time-resolved fluorescence resonance energy transfer assays revealed that cyanidin-3-O-β-glucoside functions as an agonist of LXRα.

CONCLUSION

Our results indicate that the hypocholesterolemic activity of cyanidin-3-O-β-glucoside was, at least in part, mediated by activating the potential LXRα-CYP7A1-bile acid excretion pathway, thus contributing to the antiatherogenic effect of cyanidin-3-O-β-glucoside. Importantly, cyanidin-3-O-β-glucoside could activate LXRα in an agonist-dependent manner.

Established and emerging approaches for the management of dyslipidaemia

The key role of dyslipidaemia in determining cardiovascular disease (CVD) has been proved beyond reasonable doubt, and therefore several dietary and pharmacological approaches have been developed. The discovery of statins has provided a very effective approach in reducing cardiovascular risk as documented by the results obtained in clinical trials and in clinical practice. The current efficacy of statins or other drugs, however, comes short of providing the benefit that could derive from a further reduction of LDL cholesterol (LDL-C) in high-risk and very high risk patients. Furthermore, experimental data clearly suggest that other lipoprotein classes beyond LDL play important roles in determining cardiovascular risk. For these reasons a number of new potential drugs are under development in this area. Aim of this review is to discuss the available and the future pharmacological strategies for the management of dyslipidemia.

A validated capillary electrophoresis method for simultaneous determination of ezetimibe and atorvastatin in pharmaceutical formulations

A simple, precise, and sensitive capillary electrophoresis technique coupled with a diode array detector has been developed for the separation and simultaneous determination of ezetimibe and atorvastatin in pharmaceutical formulations. Separation of both ezetimibe and atorvastatin was achieved utilizing fused silica capillary (58 cm × 75 μm ID) and background electrolyte solution that consisted of phosphate buffer (2.5 mM, pH 6.7): methanol (70:30 v/v). The proposed method was validated by testing its specificity, linearity, precision, accuracy, recovery, and detection limit/quantitation limit values. The method was linear over the range 2.5-50 μg/ml for ezetimibe (r = 0.9992) and 1-100 μg/ml for atorvastatin (r = 0.9999). Within-day and between-day RSD for ezetimibe and atorvastatin were ⩽5.6% and ⩽2.9%, respectively. The detection limit was 0.07 μg/ml for ezetimibe and 0.06 μg/ml for atorvastatin. The validated method was successfully employed for the determination of ezetimibe and atorvastatin in tablets with no interfering peaks from common pharmaceutical excipients. The percentage recoveries of the two drugs from their tablets were 99.80 ± 1.76 and 100.19 ± 1.83, respectively.

Drug treatment of hyperlipidaemia: a guide to the rational use of lipid-lowering drugs

Mammalian sterol and lipid metabolism depends on a large number of highly evolved biochemical and histological processes responsible for the absorption, distribution and steady-state anabolic/catabolic handling of these substances. Lipoproteins are complex polymolecular assemblies comprising phospholipids, cholesterol and cholesterol esters, triglycerides and a variety of apolipoproteins. The primary function of lipoproteins is to facilitate the systemic distribution of sterols and lipids. Abnormalities in lipoprotein metabolism are quite common and are attributable to a large number of genetic mutations, metabolic derangements such as insulin resistance or thyroid dysfunction, and excess availability of cholesterol and fat from dietary sources. Dyslipidaemic states facilitate endothelial dysfunction and atherogenesis. Dyslipidaemia is recognized as a risk factor for cardiovascular disease in both men and women, and people of all racial and ethnic groups throughout the world. Dyslipidaemia is modifiable with dietary change and the use of medications that impact on lipid metabolism through a variety of mechanisms. Reducing atherogenic lipoprotein burden in serum is associated with significant and meaningful reductions in risk for a variety of cardiovascular endpoints, including myocardial infarction, ischaemic stroke, development of peripheral arterial disease and mortality. This review provides an overview on how to best position lipid-lowering drugs when attempting to normalize serum lipid profiles and reduce risk for cardiovascular disease. HMG-CoA reductase inhibitors (statins) are widely accepted to be the agents of choice for reducing serum levels of low-density lipoprotein cholesterol (LDL-C) in both the primary and secondary prevention settings. Ezetimibe and bile acid sequestrants are both effective agents for reducing LDL-C, either used alone or in combination with statins. The statins, fibric acid derivatives (fibrates) and niacin raise high-density lipoprotein cholesterol to different extents depending upon genetic and metabolic background. Fibrates, niacin and omega-3 fish oils are efficacious therapies for reducing serum triglycerides. Combinations of these drugs are frequently required for normalizing mixed forms of dyslipidaemia.

Pleiotropic effects of statins. - Basic research and clinical perspectives -

Statins are 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors, which are widely used to lower serum cholesterol levels in the primary and secondary prevention of cardiovascular disease. Recent experimental and clinical evidence suggests that the beneficial effects of statins may extend beyond their cholesterol-lowering effects, to include so-called pleiotropic effects. These cholesterol-independent effects include improving endothelial function, attenuating vascular and myocardial remodeling, inhibiting vascular inflammation and oxidation, and stabilizing atherosclerotic plaques. The mechanism underlying some of these pleiotropic effects is the inhibition of isoprenoid synthesis by statins, which leads to the inhibition of intracellular signaling molecules Rho, Rac and Cdc42. In particular, inhibition of Rho and one of its downstream targets, Rho kinase, may be a predominant mechanism contributing to the pleiotropic effects of statins. The aim of the present review is to provide an update on the non-cholesterol-dependent statin effects in the cardiovascular system and highlight some of the recent findings from bench to bedside to support the concept of statin pleiotropy.

Efficacy of combination drug pulse therapy in maintaining lipid levels in patients intolerant of daily statin use

The objective of this study was to evaluate the efficacy of combination drug pulse therapy in maintaining lipid levels in patients intolerant of a daily dose of statins. Twenty-three patients, previously receiving aggressive statin therapy, were treated twice weekly with rosuvastatin or atorvastatin in different dosages along with ezetimibe as well as daily doses of bile acid sequestrant for a mean period of 4.5 months. The recommended National Cholesterol Education Program Adult Treatment Panel III goals had already been achieved in 78% of patients (n=18) before starting combination pulse therapy. This combination therapy significantly increased high-density lipoprotein cholesterol values by 5.82% (t=2.138, P=.044), while the increases in total cholesterol, low-density lipoprotein cholesterol, triglyceride, and apolipoprotein B levels compared with baseline were not statistically significant. Overall, 3 of 23 patients (13%) discontinued the combination therapy because of muscle-related symptoms over a mean course of 4.5 months of treatment.

Improvement of endothelial damage and regeneration indexes in patients with coronary artery disease after 4 weeks of statin therapy

BACKGROUND

In patients with coronary artery disease (CAD), higher numbers of circulating endothelial progenitor cells (EPC) favourably influence clinical outcome. Controversially, increased apoptosis of endothelial cells (EC) may reflect vascular damage. Statins have been shown to improve vascular damage and enhance EPC function and numbers. The availability of ezetimibe, a potent novel cholesterol absorption inhibitor, allows to distinguish between lipid-lowering and pleiotropic properties of statins.

METHODS AND FINDINGS

43 patients with CAD were assigned to receive either: de novo atorvastatin (group A; n=17), ezetimibe as add-on to chronic statin therapy (group B; n=14), or dose escalation of atorvastatin (group C; n=12) over 4 weeks. Circulating apoptotic EC (CD45-CD146+vWF+Annexin-V+) and EPC (CD34+KDR+) were quantified using flow cytometry. LDL cholesterol levels were significantly reduced in all treatment arms. Both statin groups, group A and group C, showed significantly reduced circulating apoptotic EC by 50% each (p<0.01). On the other hand, there was a significant doubling in the numbers of circulating EPC in group A and group C (p<0.005, each). Consequently, the endothelial damage-index calculated from numbers of circulating apoptotic mature EC related to EPC numbers, was improved in group A by 79% (p<0.01) and in group C by 70% (p<0.05). In contrast, sole LDL reduction by ezetimibe exerted no effect on any of the different circulating endothelial cell types.

CONCLUSION

Thus, the improvement in numbers of EPC and reduction of mature apoptotic EC after 4 weeks of statin therapy, document a novel pleiotropic effect of statin therapy in patients with CAD.

Lipid-lowering effects of ezetimibe for hypercholesterolemic patients with and without type 2 diabetes mellitus

To date, there are very few clinical reports that have compared the effects of ezetimibe on lipid parameters between hypercholesterolemic patients with and without type 2 diabetes mellitus (T2DM). In this study, we recruited patients for hypercholesterolemic groups with T2DM (n = 42; men/women = 24/18; HbA1c = 6.7 ± 5.4%) and without T2DM (n = 21; men/women = 7/14; HbA1c = 5.3 ± 0.4%). Patients were prescribed ezetimibe at a dose of 10 mg/daily for the course of the 12-week study. At baseline and after 12 weeks of treatment, several lipid parameters, including serum low-density-lipoprotein cholesterol (LDL-C), non-high-density-lipoprotein cholesterol (non-HDL-C), high-sensitivity C-reactive protein (hs-CRP), and cholesterol synthesis/absorption-related markers, were measured. Compared with those at the baseline, the levels of LDL-C, non-HDL-C, campesterol, and sitosterol were significantly reduced after 12 weeks of ezetimibe treatment in both groups. After adjusting for confounding factors, such as age, gender, smoking, and BMI, the levels of LDL-C and non-HDL-C displayed significantly greater reductions in the patients with T2DM (-25.1 ± 13.6% in LDL-C, -20.5 ± 11.2% in non-HDL-C) than those without T2DM (-20.5 ± 7.8% in LDL-C, P < 0.05; -17.4 ± 7.6% in non-HDL-C, P < 0.05). The reduction of the level of cholestanol was significantly and positively correlated with those of LDL-C and non-HDL-C in the patients with T2DM. Taken together, these findings indicate that ezetimibe could reduce the levels of atherogenic lipoproteins to a greater extent in hypercholesterolemic patients with T2DM than in those without T2DM.

Usefulness of statin-ezetimibe combination to reduce the care gap in dyslipidemia management in patients with a high risk of atherosclerotic disease

Lowering of low-density lipoprotein (LDL) cholesterol is a fundamental step in the comprehensive management of patients at high risk for cardiovascular events. The combination of a statin with ezetimibe usually provides additional LDL cholesterol lowering compared to statin monotherapy. This open-label observational study evaluated the impact of a 26-week treatment program with uptitration of statin dosages and incorporation of ezetimibe 10 mg therapy in 2,577 men and women (median age 64 years) with hypercholesterolemia and an LDL cholesterol level >2.5 mmol/L (97 mg/dl). Attainment of an LDL cholesterol target of 2.5 mmol/L (97 mg/dl) increased with consecutive visits (63%, 67%, and 71% at the second, third, and final visits, respectively). Current guideline-recommended LDL cholesterol value <2.0 mmol/L (77 mg/dl) was achieved by 36%, 40%, and 41% of the group at the same consecutive follow-up sessions. Median LDL cholesterol decreased from 3.0 mmol/L (116 mg/dl) at baseline to 2.1 mmol/L (81 mg/dl) at the end of the 26-week monitoring period. Favorable changes were concomitantly observed for median total cholesterol (5.1 to 4.1 mmol/L [197 to 159 mg/dl]), total cholesterol/high-density lipoprotein cholesterol ratio (4.2 to 3.3), and triglyceride (1.6 to 1.4 mmol/L [142 to 124 mg/dl]). Of those who attended visit 4, 48% exhibited LDL cholesterol lowering of > or =1 mmol/L (39 mg/dl) compared to baseline levels. In conclusion, an algorithm-based statin uptitration/ezetimibe combination regimen is useful to increase LDL cholesterol lowering where statin monotherapy has not achieved target lipid values.

Statins and cardiovascular diseases: from cholesterol lowering to pleiotropy

Statins are 3-hydroxy-3-methyglutaryl coenzyme A (HMG-CoA) reductase inhibitors, which are prescribed extensively for cholesterol lowering in the primary and secondary prevention of cardiovascular disease. Recent compelling evidence suggests that the beneficial effects of statins may not only be due to their cholesterol lowering effects, but also, to their cholesterol-independent or pleiotropic effects. Through these so-called pleiotropic effects, statins are directly involved in restoring or improving endothelial function, attenuating vascular remodeling, inhibiting vascular inflammatory response, and perhaps, stabilizing atherosclerotic plaques. These cholesterol-independent effects of statins are predominantly due to their ability to inhibit isoprenoid synthesis, the products of which are important lipid attachments for intracellular signaling molecules, such as Rho, Rac and Cdc42. In particular, inhibition of Rho and its downstream target, Rho-associated coiled-coil containing protein kinase (ROCK), has emerged as the principle mechanisms underlying the pleiotropic effects of statins. This review provides an update of statin-mediated vascular effects beyond cholesterol lowering and highlights recent findings from bench to bedside to support the concept of statin pleiotropy.

Effect of statins alone versus statins plus ezetimibe on carotid atherosclerosis in type 2 diabetes: the SANDS (Stop Atherosclerosis in Native Diabetics Study) trial

OBJECTIVES

This secondary analysis from the SANDS (Stop Atherosclerosis in Native Diabetics Study) trial examines the effects of lowering low-density lipoprotein cholesterol (LDL-C) with statins alone versus statins plus ezetimibe on common carotid artery intima-media thickness (CIMT) in patients with type 2 diabetes and no prior cardiovascular event.

BACKGROUND

It is unknown whether the addition of ezetimibe to statin therapy affects subclinical atherosclerosis.

METHODS

Within an aggressive group (target LDL-C <or=70 mg/dl; non-high-density lipoprotein cholesterol <or=100 mg/dl; systolic blood pressure <or=115 mm Hg), change in CIMT over 36 months was compared in diabetic individuals >40 years of age receiving statins plus ezetimibe versus statins alone. The CIMT changes in both aggressive subgroups were compared with changes in the standard subgroups (target LDL-C <or=100 mg/dl; non-high-density lipoprotein cholesterol <or=130 mg/dl; systolic blood pressure <or=130 mm Hg).

RESULTS

Mean (95% confidence intervals) LDL-C was reduced by 31 (23 to 37) mg/dl and 32 (27 to 38) mg/dl in the aggressive group receiving statins plus ezetimibe and statins alone, respectively, compared with changes of 1 (-3 to 6) mg/dl in the standard group (p < 0.0001) versus both aggressive subgroups. Within the aggressive group, mean CIMT at 36 months regressed from baseline similarly in the ezetimibe (-0.025 [-0.05 to 0.003] mm) and nonezetimibe subgroups (-0.012 [-0.03 to 0.008] mm) but progressed in the standard treatment arm (0.039 [0.02 to 0.06] mm), intergroup p < 0.0001.

CONCLUSIONS

Reducing LDL-C to aggressive targets resulted in similar regression of CIMT in patients who attained equivalent LDL-C reductions from a statin alone or statin plus ezetimibe. Common carotid artery IMT increased in those achieving standard targets. (Stop Atherosclerosis in Native Diabetics Study [SANDS]; NCT00047424).

Combination of simvastatin with berberine improves the lipid-lowering efficacy

We have identified berberine (BBR) as a novel cholesterol-lowering drug acting through stabilization of the low-density lipoprotein receptor (LDLR) messenger RNA. Because the mechanism differs from that of statins, it is of great interest to examine the lipid-lowering activity of BBR in combination with statins. Our results showed that combination of BBR with simvastatin (SIMVA) increased the LDLR gene expression to a level significantly higher than that in monotherapies. In the treatment of food-induced hyperlipidemic rats, combination of BBR (90 mg/[kg d], oral) with SIMVA (6 mg/[kg d], oral) reduced serum LDL cholesterol by 46.2%, which was more effective than that of the SIMVA (28.3%) or BBR (26.8%) monotherapy (P < .01 for both) and similar to that of SIMVA at 12 mg/(kg d) (43.4%). More effective reduction of serum triglyceride was also achieved with the combination as compared with either monotherapy. Combination of BBR with SIMVA up-regulated the LDLR messenger RNA in rat livers to a level about 1.6-fold higher than the monotherapies did. Significant reduction of liver fat storage and improved liver histology were found after the combination therapy. The therapeutic efficacy of the combination was then evaluated in 63 hypercholesterolemic patients. As compared with monotherapies, the combination showed an improved lipid-lowering effect with 31.8% reduction of serum LDL cholesterol (P < .05 vs BBR alone, P < .01 vs SIMVA alone). Similar efficacies were observed in the reduction of total cholesterol as well as triglyceride in the patients. Our results display the rationale, effectiveness, and safety of the combination therapy for hyperlipidemia using BBR and SIMVA. It could be a new regimen for hypercholesterolemia.

Use of ezetimibe in the United States and Canada

BACKGROUND

Ezetimibe lowers low-density lipoprotein cholesterol, but current lipid-lowering guidelines in the United States and Canada do not recommend it as a first option for either primary or secondary prevention. We sought to describe the adoption of ezetimibe relative to that of other lipid-lowering agents and compare its use in the two countries.

METHODS

We conducted a population-level, cohort study using data from January 2002 to December 2006, provided by IMS Health, to describe prescribing practices and expenditures for lipid-lowering agents and ezetimibe in the United States and Canada.

RESULTS

From 2002 to 2006, the monthly number of prescriptions for lipid-lowering agents rose from 3719 to 7401 per 100,000 population in Canada and from 3927 to 6827 per 100,000 population in the United States. Of these prescriptions, the proportion for ezetimibe rose from 0.2% in 2003 to 3.4% in 2006 in Canada and from 0.1% in 2002 to 15.2% in 2006 in the United States. Statin use was relatively constant between 2002 and 2006 in Canada, whereas the proportion of statin prescriptions decreased from 86.5 to 80.8% in the United States. In 2006, the ratio of prescriptions for statins to those for ezetimibe was 26:1 in Canada and 5:1 in the United States. In 2006, expenditures for ezetimibe per 100,000 population were higher in the United States than in Canada by a factor of more than 4.

CONCLUSIONS

Distinct patterns of use of ezetimibe emerged in the United States and Canada from 2002 to 2006, a difference that markedly altered the approach to the treatment of hyperlipidemia in the United States. The U.S. pattern increased overall costs, but the effect on clinical outcomes is uncertain.

Pleiotropic effects of statin therapy: molecular mechanisms and clinical results

Statins inhibit the enzyme 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase, which is required for cholesterol biosynthesis, and are beneficial in the primary and secondary prevention of cardiovascular disease. Most of the benefits of statin therapy are owing to the lowering of serum cholesterol levels. However, by inhibiting HMG-CoA reductase, statins can also inhibit the synthesis of isoprenoids, which are important lipid attachments for intracellular signaling molecules, such as Rho, Rac and Cdc42. Therefore, it is possible that statins might exert cholesterol-independent or 'pleiotropic' effects through direct inhibition of these small GTP-binding proteins. Recent studies have shown that statins might have important roles in diseases that are not mediated by cholesterol. Here, we review data from recent clinical trials that support the concept of statin pleiotropy and provide a rationale for their clinical importance.

Insights in the regulation of cholesterol 7alpha-hydroxylase gene reveal a target for modulating bile acid synthesis

The transcription of the gene (CYP7A1) encoding cholesterol 7alpha-hydroxylase, a key enzyme in cholesterol homeostasis, is repressed by bile acids via multiple mechanisms involving members of the nuclear receptor superfamily. Here, we describe a regulatory mechanism that can be exploited for modulating bile acid synthesis. By dissecting the mechanisms of CYP7A1 transcription, we found that bile acids stimulate the sequential recruitment of the histone deacetylases (HDACs) 7, 3, and 1, and of the corepressor SMRTalpha (silencing mediator of retinoid and thyroid receptors-alpha) and the nuclear corepressor. Bile acids, but not the farnesoid X receptor-selective agonist GW4064, increase the nuclear concentration of HDAC7, which promotes the assembly of a repressive complex that ultimately represses CYP7A1 transcription. Interestingly, despite its high basal expression level, small heterodimer partner (SHP) is associated with the CYP7A1 promoter only at a later stage of bile acid repression. Gene silencing with small interfering RNA confirms that HDAC7 is the key factor required for the repression of CYP7A1 transcription, whereas knockdown of SHP does not prevent the down-regulation of CYP7A1. Administration of the HDAC inhibitors valproic acid or trichostatin A to genetically hypercholesterolemic mice increases Cyp7a1 messenger RNA and bile acid synthesis and consequently markedly reduces total plasma and low-density lipoprotein cholesterol.

CONCLUSION

By using a combination of molecular, cellular, and animal models, our study highlights the importance of HDACs in the feedback regulation of CYP7A1 transcription and identifies these enzymes as potential targets to modulate bile acid synthesis and for the treatment of hypercholesterolemia.

Low-density lipoprotein cholesterol reduction: the end is more important than the means

Many epidemiologic studies and clinical trials have demonstrated the linear relation between elevated serum levels of low-density lipoprotein (LDL) cholesterol and the risk for coronary heart disease. Conversely, for each 1% reduction in LDL cholesterol in clinical trials, there is a corresponding 1% reduction in coronary heart disease risk. Although the degree of reduction is more important in affecting risk than the means used to lower LDL, statins are considered the most consistently effective means of lowering LDL. The National Cholesterol Education Program now recommends an optional goal of <70 mg/dl for patients at very high risk for coronary heart disease. In conclusion, on the basis of completed clinical trials, there is no evidence that achieving and maintaining such low levels of LDL cholesterol result in adverse effects. The most potent statins, rosuvastatin and atorvastatin, are capable of getting most patients to their LDL cholesterol goals, but combinations of statins with other drugs may be necessary for patients who require additional lipid lowering.