Ezetimibe and bile acid sequestrants: impact on lipoprotein metabolism and beyond

Attainment of Low-Density Lipoprotein Cholesterol Targets and Prescribing Pattern of Lipid-Lowering Medications among Patients with Familial Hypercholesterolemia Attending Specialist Clinics

AIMS

Patients with familial hypercholesterolemia (FH) are known to have higher exposure to coronary risk than those without FH with similar low-density lipoprotein cholesterol (LDL-C) level. Lipid-lowering medications (LLMs) are the mainstay treatments to lower the risk of premature coronary artery disease in patients with hypercholesterolemia. However, the LLM prescription pattern and its effectiveness among Malaysian patients with FH are not yet reported. The aim of this study was to report the LLM prescribing pattern and its effectiveness in lowering LDL-C level among Malaysian patients with FH treated in specialist hospitals.

METHODS

Subjects were recruited from lipid and cardiac specialist hospitals. FH was clinically diagnosed using the Dutch Lipid Clinic Network Criteria. Patients' medical history was recorded using a standardized questionnaire. LLM prescription history and baseline LDL-C were acquired from the hospitals' database. Blood samples were acquired for the latest lipid profile assay.

RESULTS

A total of 206 patients with FH were recruited. Almost all of them were on LLMs (97.6%). Only 2.9% and 7.8% of the patients achieved the target LDL-C of ＜1.4 and ＜1.8 mmol/L, respectively. The majority of patients who achieved the target LDL-C were prescribed with statin-ezetimibe combination medications and high-intensity or moderate-intensity statins. All patients who were prescribed with ezetimibe monotherapy did not achieve the target LDL-C.

CONCLUSION

The majority of Malaysian patients with FH received LLMs, but only a small fraction achieved the therapeutic target LDL-C level. Further investigation has to be conducted to identify the cause of the suboptimal treatment target attainment, be it the factors of patients or the prescription practice.

Efficacy and safety of add on therapies in patients with hypercholesterolemia undergoing statin therapy

INTRODUCTION

Statins are the first-line treatment to reduce cardiovascular (CV) events, mainly by reducing low-density-lipoprotein cholesterol (LDL-C), but many patients need additional treatments to reach the current lipid goals.

AREAS COVERED

Herein, the authors review the published literature on the efficacy and safety of the therapies that are most often added to statins to achieve lipid targets.

EXPERT OPINION

Ezetimibe is usually the first additional treatment to achieve LDL-C targets. It reduces LDL-C by about a further 20% and has an excellent safety and tolerability profile. The monoclonal antibody proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitors, evolocumab, and alirocumab, can reduce LDL-C by ≥50% when added to statins and they also have a well-established safety and tolerability record. The recently approved bempedoic acid is well tolerated and appears to be free of skeletal muscle-related problems, but the CV outcome study with this drug has not been completed. Inclisiran, a small-interfering RNA targeting PCSK9 is at an advanced stage of development and the available data indicate a satisfactory safety profile and LDL-C lowering efficacy similar to the PCSK9 monoclonal antibodies with the advantage of less frequent administration.

LDL-cholesterol: The lower the better

The reduction of low density lipoprotein-cholesterol (LDL-chol) has been associated with a decrease in cardiovascular morbidity and mortality. It has been demonstrated that there is no value of LDL-chol below which there ceases to be a preventive benefit with its reduction, and neither has it been observed that there is a higher incidence of secondary effects associated with lower concentrations of LDL-chol. Although there is a wide range of lipid-lowering drugs available, a high percentage of patients do not achieve the desired LDL-chol levels. The high-potency statins reduce the LDL-chol by 15-30%, and can double the percentage of patients that reach their desired level. This combination has shown to be safe and effective in the primary and secondary prevention of cardiovascular disease. Another option is the combination of statins with exchange resins, although this requires a more complex management. The inhibition of PCSK9 protein with monoclonal antibodies reduces the LDL-chol by more than 60%, and is effective in the prevention of cardiovascular disease. However, due to its cost, its use is restricted to patients with ischaemia or familial hypercholesterolaemia that do not achieve the desired levels with conventional drugs. The evidence base as regards the benefit and safety of achieving the desired levels of LDL-chol is very wide and is still increasing. In the next few years, it may be necessary to adjust the intensity of the hypercholesterolaemia treatment to the level of vascular risk of the patients, and to the level of reduction necessary to achieve the therapeutic targets. This will result in a more effective cardiovascular prevention and in a better quality of life, particularly in the large group of patients at higher vascular risk.

Ezetimibe in Combination With Simvastatin Reduces Remnant Cholesterol Without Affecting Biliary Lipid Concentrations in Gallstone Patients

Background

In randomized trials (SHARP [Study of Heart and Renal Protection], IMPROVE‐IT [Improved Reduction of Outcomes: Vytorin Efficacy International Trial]), combination of statin and ezetimibe resulted in additional reduction of cardiovascular events. The reduction was greater in patients with type 2 diabetes mellitus (T2DM), where elevated remnant cholesterol and high cardiovascular disease risk is characteristic. To evaluate possible causes behind these results, 40 patients eligible for cholecystectomy, randomized to simvastatin, ezetimibe, combined treatment (simvastatin+ezetimibe), or placebo treatment during 4 weeks before surgery, were studied.

Methods and Results

Fasting blood samples were taken before treatment start and at the end (just before surgery). Bile samples and liver biopsies were collected during surgery. Hepatic gene expression levels were assessed with qPCR. Lipoprotein, apolipoprotein levels, and content of cholesterol, cholesteryl ester, and triglycerides were measured after lipoprotein fractionation. Lipoprotein subclasses were analyzed by nuclear magnetic resonance. Apolipoprotein affinity for human arterial proteoglycans (PG) was measured. Biomarkers of cholesterol biosynthesis and intestinal absorption and bile lipid composition were analyzed using mass spectrometry. Combined treatment caused a statistically significant decrease in plasma remnant particles and apolipoprotein B (ApoB)/lipoprotein content of cholesterol, cholesteryl esters, and triglycerides. All treatments reduced ApoB‐lipoprotein PG binding. Simvastatin and combined treatment modified the composition of lipoproteins. Changes in biomarkers of cholesterol synthesis and absorption and bile acid synthesis were as expected. No adverse events were found.

Conclusions

Combined treatment caused atheroprotective changes on ApoB‐lipoproteins, remnant particles, bile components, and in ApoB‐lipoprotein affinity for arterial PG. These effects might explain the decrease of cardiovascular events seen in the SHARP and IMPROVE‐IT trials.

Clinical Trial Registration

URL: www.clinicaltrialsregister.eu. Unique identifier: 2006‐004839‐30).

Lipid management in patients with chronic kidney disease

An increased risk of cardiovascular disease, independent of conventional risk factors, is present even at minor levels of renal impairment and is highest in patients with end-stage renal disease (ESRD) requiring dialysis. Renal dysfunction changes the level, composition and quality of blood lipids in favour of a more atherogenic profile. Patients with advanced chronic kidney disease (CKD) or ESRD have a characteristic lipid pattern of hypertriglyceridaemia and low HDL cholesterol levels but normal LDL cholesterol levels. In the general population, a clear relationship exists between LDL cholesterol and major atherosclerotic events. However, in patients with ESRD, LDL cholesterol shows a negative association with these outcomes at below average LDL cholesterol levels and a flat or weakly positive association with mortality at higher LDL cholesterol levels. Overall, the available data suggest that lowering of LDL cholesterol is beneficial for prevention of major atherosclerotic events in patients with CKD and in kidney transplant recipients but is not beneficial in patients requiring dialysis. The 2013 Kidney Disease: Improving Global Outcomes (KDIGO) Clinical Practice Guideline for Lipid Management in CKD provides simple recommendations for the management of dyslipidaemia in patients with CKD and ESRD. However, emerging data and novel lipid-lowering therapies warrant some reappraisal of these recommendations.

[Pharmacological targets for dislipidemies correction. Opportunities and prospects of therapeutic usage]

Literature data on influence of existing and new groups of drug preparations for dyslipidemias correction are systemized, and molecular mechanisms of their effects are reviewed. The results of experimental and clinical investigations aimed at revealing of new pharmacological targets of dyslipidemias correction were analyzed. The approaches for activation of high density lipoproteins functionality are described. The implementation of alternative preparations with new alternative mechanisms of action may be suggested to improve the effectiveness of traditional treatment in the future.

The Spectrum of Familial Hypercholesterolemia (FH) in Saudi Arabia: Prime Time for Patient FH Registry

BACKGROUND

Familial hypercholesterolemia (FH) is a life-threatening inherited condition. Untreated patients have the risk to develop raised plasma levels of cholesterol, atherosclerosis and cardiovascular disease (CVD). If diagnosed and treated early in life, the pathological consequences due to atherosclerosis could be avoided and patients with FH can have an anticipated normal life. Mounting evidence suggests that FH is underdiagnosed and undertreated in all populations. The underlying molecular basis of FH is the presence of mutations in one or more genes in the low-density lipoprotein receptor (LDLR), apolipoprotein B (APOB) or proprotein convertase subtilisin/kexin 9 (PCSK9). However, their prevalence is largely unknown in Saudi Arabia but given the high rates of consanguinity, the prevalence appears to be higher. Furthermore, the high prevalence of obesity and diabetes mellitus in Saudi Arabia increases the vascular disease burden in FH cases by adding additional CVD risk factors.

OBJECTIVE

This article explores the spectrum of FH-causing mutations in the highly consanguineous Saudi community, the need for establishing the Saudi FH registry, the challenges in creating gene databases, and cascade screening.

CONCLUSION

The establishment of FH registry and genetic testing should raise awareness not only among healthcare professionals, but the general population as well. It also helps to provide the best treatment regimen in a cost effective manner to this under-recognised population of FH patients.

The effects of amoxicillin and vancomycin on parameters reflecting cholesterol metabolism

BACKGROUND

Changes in the microbiota composition have been implicated in the development of obesity and type 2 diabetes. However, not much is known on the involvement of gut microbiota in lipid and cholesterol metabolism. In addition, the gut microbiota might also be a potential source of plasma oxyphytosterol and oxycholesterol concentrations (oxidation products of plant sterols and cholesterol). Therefore, the aim of this study was to modulate the gut microbiota by antibiotic therapy to investigate effects on parameters reflecting cholesterol metabolism and oxyphytosterol concentrations.

DESIGN

A randomized, double blind, placebo-controlled trial was performed in which 55 obese, pre-diabetic men received oral amoxicillin (broad-spectrum antibiotic), vancomycin (antibiotic directed against Gram-positive bacteria) or placebo (microcrystalline cellulose) capsules for 7days (1500mg/day). Plasma lipid and lipoprotein, non-cholesterol sterol, bile acid and oxy(phyto)sterol concentrations were determined at baseline and after 1-week intervention.

RESULTS

Plasma secondary bile acids correlated negatively with cholestanol (marker for cholesterol absorption, r=-0.367; P<0.05) and positively with lathosterol concentrations (marker for cholesterol synthesis, r=0.430; P<0.05). Fasting plasma secondary bile acid concentrations were reduced after vancomycin treatment as compared to placebo treatment (-0.24±0.22μmol/L vs. -0.08±0.29μmol/L; P<0.01). Vancomycin and amoxicillin treatment did not affect markers for cholesterol metabolism, plasma TAG, total cholesterol, LDL-C or HDL-C concentrations as compared to placebo. In addition, both antibiotic treatments did not affect individual isoforms or total plasma oxyphytosterol or oxycholesterol concentrations.

CONCLUSION

Despite strong correlations between plasma bile acid concentrations and cholesterol metabolism (synthesis and absorption), amoxicillin and vancomycin treatment for 7days did not affect plasma lipid and lipoprotein, plasma non-cholesterol sterol and oxy(phyto)sterol concentrations in obese, pre-diabetic men.

HMG-CoA Reductase inhibitors: an updated review of patents of novel compounds and formulations (2011-2015)

INTRODUCTION

Statins are remarkably safe and efficient medications that are the mainstay of hypercholesterolemia treatment and have proven to be an invaluable tool to lower the risk of acute cardiovascular events. These compounds are inhibitors of 3-hydroxy-methylglutaryl CoA reductase (HMG-R), the rate-limiting enzyme in cholesterol biosynthesis. In spite of their success, they present undesirable side effects and are now loosing patent protection, which provides a great opportunity for the development of new and improved statins. Areas covered: This review summarizes the new patents for HMG-R inhibitors for the 2011-2015 period. Combinations of existing statins with other drugs are also addressed, as well as novel applications of existing statins. Expert opinion: Recent efforts for the discovery of HMG-CoA-R inhibitors has resulted in several new molecules. Most of these are based on commercially available statins, including sterol and terpenoid derivatives. A few peptides have also been patented. However, the origin of the side effects caused by previous statins continues to be, to a large extent, unknown. Although the patents published in the past 5 years are promising, and might result in new drugs, there is still no way to know if they will present reduced toxicity. Only future clinical trials will answer this question.

The effect of colesevelam treatment on bile acid and lipid metabolism and glycemic control in healthy men

The treatment of hypercholesterolemia with bile acid (BA) sequestrants results in upregulation of BA synthesis through the classical pathway initiated by cholesterol 7alpha-hydroxylase (CYP7A1). To characterize the detailed dynamics of serum lipid and BA concentrations and the BA synthesis rate in response to treatment with BA sequestrants and to determine whether the -203A/C promoter polymorphism of the CYP7A1 encoding gene (CYP7A1) affects such a response, this pilot study was carried out in healthy men (8 homozygous for the -203A allele and 8 homozygous for the -203C allele of CYP7A1). The subjects were treated for 28 days with colesevelam and blood was drawn for analysis before and on days 1, 3, 7, 14 and 28 of treatment. The response of lipids, BA, fibroblast growth factor-19 (FGF19) and 7alpha-hydroxy-4-cholesten-3-one (C4) to colesevelam did not differ between carriers of -203A and -203C alleles; their data were then aggregated for further analysis. Colesevelam treatment caused immediate suppression of FGF19 concentration and a fivefold increase in CYP7A1 activity, as assessed from C4 concentration, followed by a 17 % decrease in LDL-cholesterol. Although total plasma BA concentrations were not affected, the ratio of cholic acid/total BA rose from 0.25+/-0.10 to 0.44+/-0.16 during treatment at the expense of decreases in chenodeoxycholic and deoxycholic acid.

Lipid lowering efficacy and safety of Ezetimibe combined with rosuvastatin compared with titrating rosuvastatin monotherapy in HIV-positive patients

Background

HIV-infected patients on antiretroviral therapy frequently develop dyslipidemias and, despite therapy with potent lipid-lowering agents, a high percentage does not achieve guideline recommended lipid targets. In this study, we examined the efficacy of combination treatment with a statin and the cholesterol transport blocker, ezetimibe, vs. monotherapy with a statin in HIV-infected patients not achieving lipid goals.

Methods

This was a 12-week, prospective, randomized, open-label clinical trial. Patients were eligible if they had an apolipoprotein B (apoB) >0.80 g/L despite therapy with rosuvastatin 10 mg daily for a minimum of 12 weeks. Patients were randomized to take ezetimibe 10 mg/rosuvastatin 10 mg or rosuvastatin 20 mg for 12 weeks. Percentage and absolute change in apoB (primary outcome), low-density lipoprotein cholesterol (LDL-C), total cholesterol (TC), triglyceride (TG), high-density lipoprotein cholesterol (HDL-C), non-HDL-C, apoliporpotein A1 (apoA1), apoB/apoA1, TC/HDL-C, atherogenic index of plasma (API), and high-sensitivity C-reactive protein (hsCRP) were compared. Changes in safety parameters (such as AST, ALT, CK) and clinical symptoms were also assessed.

Results

Forty-three patients (23 on ezetimibe 10 mg/rosuvastatin 10 mg and 20 on rosuvastatin 20 mg) completed the trial. Baseline characteristics did not differ between the groups. Significant improvements in apoB were seen with both ezetimibe plus rosuvastatin (mean of -0.17 g/L, p < 0.001) and rosuvastatin 20 mg (mean of -0.13 g/L, p = 0.03) treatment groups, but did not differ between groups (p = 0.53). Significant between-group differences were observed for mean TC (-1.01 mmol/L vs. -0.50 mmol/L, p = 0.03), TG (-0.62 mmol/L vs -0.17 mmol/L, p = 0.03), and non-HDL-C (-0.97 mmol/L vs. -0.53 mmol/L, p = 0.03) all in favour of the ezetimibe plus rosuvastatin group. Two patients, both in the rosuvastatin 20 mg group, experienced mild myalgias; neither discontinued the study.

Conclusions

The addition of ezetimibe to rosuvastatin appears to be safe in patients with HIV. Furthermore, the combination of ezetimibe and rosuvastatin improved TG, AIP and non-HDL cholesterol levels more than a dose increase in rosuvastatin in patients with HIV-associated dyslipidemia.

Triple Recycling Processes Impact Systemic and Local Bioavailability of Orally Administered Flavonoids

Triple recycling (i.e., enterohepatic, enteric and local recycling) plays a central role in governing the disposition of phenolics such as flavonoids, resulting in low systemic bioavailability but higher gut bioavailability and longer than expected apparent half-life. The present study aims to investigate the coexistence of these recycling schemes using model bioactive flavonoid tilianin and a four-site perfused rat intestinal model in the presence or absence of a lactase phlorizin hydrolase (LPH) inhibitor gluconolactone and/or a glucuronidase inhibitor saccharolactone. The result showed that tilianin could be metabolized into tilianin glucuronide, acacetin, and acacetin glucuronide, which are excreted into the bile and luminal perfusate (highest in the duodenum and lowest in the colon). Gluconolactone (20 mM) significantly reduced the absorption of tilianin and the enteric and biliary excretion of acacetin glucuronide. Saccharolactone (0.1 mM) alone or in combination of gluconolactone also remarkably reduced the biliary and intestinal excretion of acacetin glucuronide. Acacetin glucuronides from bile or perfusate were rapidly hydrolyzed by bacterial β-glucuronidases to acacetin, enabling enterohepatic and enteric recycling. Moreover, saccharolactone-sensitive tilianin disposition and glucuronide deconjugation, which was more active in the small intestine than the colon, points to the small intestinal origin of the deconjugation enzyme and supports the presence of local recycling scheme. In conclusion, our studies have demonstrated triple recycling of a bioactive phenolic (i.e., a model flavonoid), and this recycling may have an impact on the site and duration of polyphenols pharmacokinetics in vivo.

Glucagon-like peptide-1 receptor agonists for the treatment of type 2 diabetes: differences and similarities

Glucagon-like peptide-1 (GLP-1) is a gastrointestinal hormone, secreted in response to ingestion of nutrients, and has important effects on several of the pathophysiological features of type 2 diabetes (T2D). The effects include potentiation of insulin secretion, suppression of glucagon secretion, slowing of gastric emptying and suppression of appetite. In circulation, GLP-1 has a half-life of approximately 2min due to rapid degradation by the enzyme dipeptidyl peptidase 4 (DPP-4). Because of this short half-life GLP-1 receptor (GLP-1R) agonists, resistant to degradation by DPP-4 have been developed. At the moment four different compounds are available for the treatment of T2D and many more are in clinical development. These compounds, although all based on the effects of native GLP-1, differ with regards to structure, pharmacokinetics and size, which ultimately leads to different clinical effects. This review gives an overview of the clinical data on GLP-1R agonists that have been compared in head-to-head studies and focuses on relevant differences between the compounds. Highlighting these similarities and differences could be beneficial for physicians in choosing the best treatment strategy for their patients.

The ebbs and flows in the development of cholesterol-lowering drugs: prospects for the future

Cardiovascular disease (CVD) is the leading cause of mortality worldwide, and its prevalence is increasing worldwide. Statins are the mainstay of treatment but do not address all aspects of CVD risk. Other lipid-lowering therapies are available but are less effective than statins. New therapies to lower low-density-lipoprotein cholesterol (LDL-C) by as much as statins, to reduce triglycerides (TGs), and to modify the metabolism of high-density lipoproteins (HDLs) are in development.

Toward individualized cholesterol-lowering treatment in end-stage renal disease

There is broad evidence that lowering low-density lipoprotein (LDL) cholesterol will reduce cardiovascular risk. However, in patients on maintenance hemodialysis treatment, lowering LDL cholesterol is not as effective in preventing cardiovascular complications as in the general population. Cholesterol is either endogenously synthesized or absorbed from the intestine. It has been suggested that the benefit of using statins to prevent atherosclerotic complications is less pronounced in people with high absorption of cholesterol. Recent data indicate that patients on hemodialysis have high absorption of cholesterol. Therefore, these patients may benefit from dietary counseling to reduce cholesterol intake, from functional foods containing plant sterols and stanols, and from drugs that interfere with intestinal absorption of sterols (i.e., ezetimibe, bile acid resins, and sevelamer). This review discusses cholesterol homeostasis and the perspective of personalized treatment of hypercholesterolemia in hemodialysis.

Hyodeoxycholic acid improves HDL function and inhibits atherosclerotic lesion formation in LDLR-knockout mice

We examined the effects of a natural secondary bile acid, hyodeoxycholic acid (HDCA), on lipid metabolism and atherosclerosis in LDL receptor-null (LDLRKO) mice. Female LDLRKO mice were maintained on a Western diet for 8 wk and then divided into 2 groups that received chow, or chow + 1.25% HDCA, diets for 15 wk. We observed that mice fed the HDCA diet were leaner and exhibited a 37% (P<0.05) decrease in fasting plasma glucose level. HDCA supplementation significantly decreased atherosclerotic lesion size at the aortic root region, the entire aorta, and the innominate artery by 44% (P<0.0001), 48% (P<0.01), and 94% (P<0.01), respectively, as compared with the chow group. Plasma VLDL/IDL/LDL cholesterol levels were significantly decreased, by 61% (P<0.05), in the HDCA group as compared with the chow diet group. HDCA supplementation decreased intestinal cholesterol absorption by 76% (P<0.0001) as compared with the chow group. Furthermore, HDL isolated from the HDCA group exhibited significantly increased ability to mediate cholesterol efflux ex vivo as compared with HDL of the chow diet group. In addition, HDCA significantly increased the expression of genes involved in cholesterol efflux, such as Abca1, Abcg1, and Apoe, in a macrophage cell line. Thus, HDCA is a candidate for antiatherosclerotic drug therapy.