Double-blind randomized clinical trial of the effects of ezetimibe on postprandial hyperlipidaemia and hyperglycaemia

Novel polymorphism of HMGCR gene related to the risk of diabetes in premature triple-vessel disease patients

BACKGROUND

Coronary heart disease and diabetes are highly interrelated and complex diseases. We proposed to investigate the association of genetic polymorphisms of the lipoprotein important regulatory genes Niemann-Pick C1-like 1 (NPC1L1) and 3-hydroxy-3-methylglutaryl-coenzyme A reductase (HMGCR) in patients with premature triple-vessel coronary disease (PTVD) with diabetes, blood glucose and body mass index (BMI).

METHODS

Four single-nucleotide polymorphisms (SNPs) (rs11763759, rs4720470, rs2072183, rs2073547) of NPC1L1, and three SNPs (rs12916, rs2303151, rs4629571) of HMGCR were genotyped in 872 PTVD patients.

RESULTS

After performing logistic regression analysis adjusted for age and sex, rs2303151 of HMGCR was related to the risk of diabetes in dominance model (odds ratio [OR]=1.35, 95% confidence intervals [CI]: 1.01-1.80, P=0.04). However, the four SNPs of NPC1L1 were not associated with the risk of diabetes. Further analyses showed that neither the above SNPs of NPC1L1 nor the SNPs of HMGCR were related to blood glucose and body mass index (all P>0.05).

CONCLUSION

We firstly report that rs2303151 is a novel polymorphism of HMGCR gene related to the risk of diabetes in PTVD patients, which suggests HMGCR may be a potential common targeted pathogenic pathways between the coronary heart disease and diabetes.

Orlistat and ezetimibe could differently alleviate the high-fat diet-induced obesity phenotype by modulating the gut microbiota

This study aimed to evaluate the possible anti-obesity effects of orlistat and ezetimibe and determine the mechanism by which they alter the composition of gut microbiota and short-chain fatty acids (SCFAs) in mice with a high-fat diet (HFD)-induced obesity. Eighty male, specific pathogen-free C57BL/6J mice aged 3 weeks were divided into four groups (n = 20). The NCD group was fed with a normal diet, and the HFD, HFD+ORL, and HFD+EZE groups were fed with HFD for 20 weeks. From the 13th week onward, the HFD+ORL and HFD+EZE groups were administered with orlistat and ezetimibe, respectively. The glucose and lipid metabolism of the tested mice were evaluated by analyzing blood biochemical indicators during the intervention. Furthermore, the changes in the structure of the fecal microbiota and the fecal SCFA content were analyzed by 16S rRNA sequencing and gas chromatography-mass spectrometry, respectively. HFD induced the obesity phenotype in mice. Compared to the HFD group, the body weight, visceral fat-to-body weight ratio, serum total cholesterol (TC), high-density lipoprotein-cholesterol (HDL-C), and oral glucose tolerance test (OGTT) of the HFD+ORL group significantly decreased, whereas fecal butyric acid levels significantly increased. Ezetimibe intervention significantly reduced the OGTT, serum TC, and HDL-C levels only. The α-diversity of the gut microbiota significantly decreased after intervention with orlistat and ezetimibe. Orlistat altered the relative abundance of some bacteria in the fecal microbiota. The populations of Firmicutes, Alistipes, and Desulfovibrio decreased, whereas those of Verrucomicrobia and Akkermansia significantly increased. Ezetimibe caused changes only in some low-abundance bacteria, as manifested by a decrease in Proteobacteria and Desulfovibrio, and an increase in Bacteroides. The administration of orlistat and ezetimibe can characteristically influence the body weight and serum lipid metabolism, and glucolipid levels in diet-induced obese mice and is accompanied by significant changes in the gut microbiota and SCFAs. These results suggest that the two drugs might exert their own specific anti-obesity effects by modulating the gut microbiota in a different manner. The enhanced health-promoting effect of orlistat might result from its stronger ability to alter the gut microbiota and SCFAs, at least partly.

Diabetes and Familial Hypercholesterolemia: Interplay between Lipid and Glucose Metabolism

Familial hypercholesterolemia (FH) is a genetic disease characterized by high low-density lipoprotein (LDL) cholesterol (LDL-c) concentrations that increase cardiovascular risk and cause premature death. The most frequent cause of the disease is a mutation in the LDL receptor (LDLR) gene. Diabetes is also associated with an increased risk of cardiovascular disease and mortality. People with FH seem to be protected from developing diabetes, whereas cholesterol-lowering treatments such as statins are associated with an increased risk of the disease. One of the hypotheses to explain this is based on the toxicity of LDL particles on insulin-secreting pancreatic β-cells, and their uptake by the latter, mediated by the LDLR. A healthy lifestyle and a relatively low body mass index in people with FH have also been proposed as explanations. Its association with superimposed diabetes modifies the phenotype of FH, both regarding the lipid profile and cardiovascular risk. However, findings regarding the association and interplay between these two diseases are conflicting. The present review summarizes the existing evidence and discusses knowledge gaps on the matter.

Efficacy and safety of icosapent ethyl in hypertriglyceridaemia: a recap

Although low-density lipoprotein cholesterol lowering is effective in atherosclerotic cardiovascular disease (ASCVD) prevention, considerable ‘lipid-associated’ residual risk remains, particularly in patients with mild-to-moderate hypertriglyceridaemia (2–10 mmol/L; 176–880 mg/dL). Triglyceride (TG)-rich lipoproteins carry both TGs and cholesterol (remnant-cholesterol). At TG levels >5 mmol/L (440 mg/dL) vs. <1 mmol/L (88 mg/dL) or remnant-cholesterol >2.3 mmol/L (89 mg/dL) vs. <0.5 mmol/L (19 mg/dL), risk is ∼1.5-fold elevated for aortic stenosis, 2-fold for all-cause mortality, 3-fold for ischaemic stroke, 5-fold for myocardial infarction (MI), and 10-fold for acute pancreatitis. Furthermore, Mendelian randomization studies indicate that elevated TG-rich lipoproteins are causally related to increased risk of ASCVD and even all-cause mortality. While genetic and epidemiological data strongly indicate that TG-rich lipoproteins are causally linked to ASCVD, intervention data are ambiguous. Fibrates, niacin and low-dose omega-3 fatty acids have all been used in outcome trials, but have failed to demonstrate clear benefit in combination with statins. Whether the lack of additional benefit relates to methodological issues or true failure is indeterminate. Importantly, a recent intervention trial evaluating a high dose of eicosapentaenoic-acid showed clear benefit. Thus, REDUCE-IT evaluated the effect of icosapent ethyl (4 g/day) on cardiovascular outcomes in 8179 high-risk patients with moderate TG elevation on statin therapy. Over a median duration of 4.9 years, the relative risk for the primary endpoint (composite of cardiovascular death, non-fatal MI, non-fatal stroke, coronary revascularization, or unstable angina) was reduced by 25% (absolute risk 17.2% vs. 22.0%; P < 0.0001; number needed to treat 21). High-dose icosapent ethyl intervention therefore confers substantial cardiovascular benefit in high-risk patients with moderate hypertriglyceridaemia on statin therapy.

Postprandial hyperlipidemia as a risk factor in patients with type 2 diabetes

Introduction: Postprandial hyperlipidemia is a common feature of the atherogenic dyslipidemia in patients with type 2 diabetes. Quantification of this with oral fat tolerance tests is not used routinely in clinical practice and abnormal postprandial lipids are usually inferred from non-fasting plasma triglyceride levels. Identifying excessive postprandial hyperlipidemia may help to refine cardiovascular risk assessment but there are no treatments currently available which selectively target postprandial lipids and no large cardiovascular outcome trials using this as the entry criterion.Areas covered: In this review of relevant published material, we summarize the findings from the most important publications in this area.Expert opinion: Postprandial hyperlipidemia appears to contribute to the cardiovascular risk in patients with diabetes. Non-fasting triglyceride levels provide a surrogate marker of postprandial hyperlipidemia but more specific markers such as apoB48 levels may prove to be more reliable. Omega-3 fatty acids, fibrates and ezetimibe can reduce postprandial lipids but may not correct them completely. Several novel treatments have been developed to target hypertriglyceridemia and some of these may be particularly effective in improving postprandial levels. Further clinical trials are needed to establish the role of postprandial lipids in assessment of cardiovascular risk and to identify the most effective treatments.

Effect of ezetimibe on glycemic control: a systematic review and meta-analysis of randomized controlled trials

PURPOSE

Given the increased risk of incident diabetes and the side effects on glycemic control with statin treatment, statin and ezetimibe combination therapy has been widely used. However, whether the same concern exists in ezetimibe remains uncertain. This meta-analysis aimed to investigate the influence of ezetimibe treatment on glycemic control.

METHODS

Articles were searched from PubMed, EMBASE, and Cochrane Library. Randomized controlled trials (RCTs) were included if they compared the effects of ezetimibe with placebo, ezetimibe plus statin with the same statin, or low-dose stain plus ezetimibe with high-dose statin on FBG and glycosylated hemoglobin A1c (HbA1c).

RESULTS

Of the 2440 articles retrieved, 16 RCTs were included. Ezetimibe did not cause side effects on FBG (WMD -0.62, 95% CI: -3.13 to 1.90) and HbA1c (WMD 0.07, 95% CI: -0.07 to 0.20%). No significant changes in FBG (WMD -1.78, 95% CI: -6.33 to 2.77%) and HbA1c (WMD -0.05, 95% CI: -0.14 to 0.05%) were observed in ezetimibe plus low-dose statin treatment compared with high-dose statin. According to subgroup analysis, in comparison with high-dose statin, ezetimibe plus low-dose statin taken for more than 3 months showed a significant decrease in FBG (WMD -7.12, 95% CI: -13.86 to -0.38%) compared with that taken for less than 3 months (WMD 0.90, 95% CI: -2.91 to 4.71%). Nevertheless, this difference was invalid when the study conducted by Dagli et al. was removed.

CONCLUSIONS

Compared with high-dose statin therapy, ezetimibe with low-dose statin for more than 3 months may have a beneficial tendency of effects on glycemic control.

Effect of ezetimibe on plasma adipokines: a systematic review and meta-analysis

AIMS

Statins are known to influence the status of adipokines, which play a key role in the pathophysiology of cardiometabolic diseases. As the effect of ezetimibe as an add-on to statin therapy on the impact of statins on plasma adipokines levels is currently unclear, the aim of the present study was to investigate this through a meta-analysis of controlled trials.

METHODS

A systematic review was performed, followed by a bibliographic search in PubMed, Medline, SCOPUS, Web of Science and Google Scholar databases. Quantitative data synthesis was performed using a fixed- or random-effects model (based on the level of interstudy heterogeneity) and the generic inverse variance weighting method. Effect sizes were expressed as standardized mean difference (SMD) and 95% confidence interval (CI).

RESULTS

Meta-analysis of 23 controlled trials did not suggest any significant effect of adding ezetimibe on top of statin therapy on plasma concentrations of adiponectin (SMD 0.34, 95% CI -0.28, 0.96; P = 0.288), leptin (SMD -0.75, 95% CI: -2.35, 0.85; P = 0.360), plasminogen activator inhibitor 1 (SMD -1.06, 95% CI: -2.81, 0.69; P = 0.236) and interleukin 6 (SMD 0.30, 95% CI: -0.08, 0.67; P = 0.124). However, significantly greater reductions in plasma concentrations of tumour necrosis factor α (TNF-α) (SMD -0.48, 95% CI -0.87, -0.08; P = 0.018) were achieved with ezetimibe/statin combination therapy.

CONCLUSIONS

The results suggested that ezetimibe add-on to statin therapy is associated with an enhanced TNF-α-lowering effect compared with statin monotherapy. Owing to the emerging role of TNF-α in the pathogenesis of metabolic disorders, further investigations are required to unveil the translational relevance of this TNF-α-lowering effect.

Vascular Disease Is Associated With the Expression of Genes for Intestinal Cholesterol Transport and Metabolism

CONTEXT

Intestinal cholesterol metabolism is important in influencing postprandial lipoprotein concentrations, and might be important in the development of vascular disease.

OBJECTIVE

This study evaluated associations between expression of intestinal cholesterol metabolism genes, postprandial lipid metabolism, and endothelial function/early vascular disease in human subjects.

DESIGN/PATIENTS

One hundred patients undergoing routine oesophago-gastro-duodenoscopy were recruited. mRNA levels of Nieman-Pick C1-like 1 protein (NPC1L1), ABC-G5, ABC-G8, ABC-A1, microsomal tissue transport protein (MTTP), and sterol-regulatory element-binding protein (SREBP)-2 were measured in duodenal biopsies using quantitative reverse transcription polymerase chain reaction. Postprandially, serum lipid and glycemic profiles were measured, endothelial function was assessed using fasting, and postprandial flow-mediated dilatation (FMD) and carotid intima-media thickness (IMT). Subjects were divided into those above and below the median value of relative expression of each gene, and results were compared between the groups.

RESULTS

There were no between-group differences in demographic variables or classical cardiovascular risks. For all genes, the postprandial triglyceride incremental area under the curve was greater (P < 0.05) in the group with greater expression. Postprandial apolipoprotein B48 (ApoB48) levels were greater (P < 0.05) in groups with greater expression of NPC1L1, ABC-G8, and SREBP-2. For all genes, postprandial but not fasting FMD was lower (P < 0.01) in the group with greater expression. Triglyceride and ApoB48 levels correlated significantly with postprandial FMD. Carotid artery IMT was greater (P < 0.05) in groups with greater expression of MTTP, ABC-A1, and SREBP-2.

CONCLUSION

Intestinal cholesterol metabolism gene expression is significantly associated with postprandial increment in triglycerides, intestinal ApoB48, and reduced postprandial FMD. Some genes were also associated with increased IMT. These findings suggest a role of intestinal cholesterol metabolism in development of early vascular disease.

Postprandial Hyperlipidemia and Remnant Lipoproteins

Fasting hypertriglyceridemia is positively associated with the morbidity of coronary heart disease (CHD), and postprandial (non-fasting) hypertriglyceridemia is also correlated with the risk status for CHD, which is related to the increase in chylomicron (CM) remnant lipoproteins produced from the intestine. CM remnant particles, as well as oxidized low density lipoprotein (LDL) or very low density lipoprotein (VLDL) remnants, are highly atherogenic and act by enhancing systemic inflammation, platelet activation, coagulation, thrombus formation, and macrophage foam cell formation. The cholesterol levels of remnant lipoproteins significantly correlate with small, dense LDL; impaired glucose tolerance (IGT) and CHD prevalence. We have developed an assay of apolipoprotein (apo)B-48 levels to evaluate the accumulation of CM remnants. Fasting apoB-48 levels correlate with the morbidity of postprandial hypertriglyceridemia, obesity, type III hyperlipoproteinemia, the metabolic syndrome, hypothyroidism, chronic kidney disease, and IGT. Fasting apoB-48 levels also correlate with carotid intima-media thickening and CHD prevalence, and a high apoB-48 level is a significant predictor of CHD risk, independent of the fasting TG level. Diet interventions, such as dietary fibers, polyphenols, medium-chain fatty acids, diacylglycerol, and long-chain n-3 polyunsaturated fatty acids (PUFA), ameliorate postprandial hypertriglyceridemia, moreover, drugs for dyslipidemia (n-3 PUFA, statins, fibrates or ezetimibe) and diabetes concerning incretins (dipeptidyl-peptidase IV inhibitor or glucagon like peptide-1 analogue) may improve postprandial hypertriglyceridemia. Since the accumulation of CM remnants correlates to impaired lipid and glucose metabolism and atherosclerotic cardiovascular events, further studies are required to investigate the characteristics, physiological activities, and functions of CM remnants for the development of new interventions to reduce atherogenicity.

The Glucotoxicity Protecting Effect of Ezetimibe in Pancreatic Beta Cells via Inhibition of CD36

Inhibition of CD36, a fatty acid transporter, has been reported to prevent glucotoxicity and ameliorate high glucose induced beta cell dysfunction. Ezetimibe is a selective cholesterol absorption inhibitor that blocks Niemann Pick C1-like 1 protein, but may exert its effect through suppression of CD36. We attempted to clarify the beneficial effect of ezetimibe on insulin secreting cells and to determine whether this effect is related to change of CD36 expression. mRNA expression of insulin and CD36, intracellular peroxide level and glucose stimulated insulin secretion (GSIS) under normal (5.6 mM) or high glucose (30 mM) condition in INS-1 cells and primary rat islet cells were compared. Changes of the aforementioned factors with treatment with ezetimibe (20 μM) under normal or high glucose condition were also assessed. mRNA expression of insulin was decreased with high glucose, which was reversed by ezetimibe in both INS-1 cells and primary rat islets. CD36 mRNA expression was increased with high glucose, but decreased by ezetimibe in INS-1 cells and primary rat islets. Three-day treatment with high glucose resulted in an increase in intracellular peroxide level; however, it was decreased by treatment with ezetimibe. Decrease in GSIS by three-day treatment with high glucose was reversed by ezetimibe. Palmitate uptake following exposure to high glucose conditions for three days was significantly elevated, which was reversed by ezetimibe in INS-1 cells. Ezetimibe may prevent glucotoxicity in pancreatic β-cells through a decrease in fatty acid influx via inhibition of CD36.

Potential Drug Combinations to Reduce Cardiovascular Disease Burden in Diabetes

The major cause of death and complications in patients with type 2 diabetes (T2DM) is cardiovascular disease (CVD). More than 60% of all patients with T2DM die of CVD, and an even greater percentage have serious complications. The impact of glucose lowering on cardiovascular complications is a hotly debated issue and recent large clinical trials reported no significant decrease in cardiovascular events with intensive glucose control. Risk remains high even after correcting diabetes-associated dyslipidemia with drugs such as fibrates and niacin. Data from several clinical studies show that postprandial glucose and lipids have a strong predictive value on myocardial infarction (MI) and mortality. However, strategies to reduce postprandial hyperglycemia and/or lipemia through increased utilization of glucose and/or triglycerides (TG) have been shown to not be effective in reducing the CVD burden. In this review, I discus the preferred ways to reduce postprandial glucose and TG with combinations of currently marketed drugs with potential benefit in CVD.

Ezetimibe/statin combination therapy to treat patients with type 2 diabetes

Patients with diabetes represent a population at higher risk for cardiovascular disease. Diabetic dyslipidemia is characterized by the so-called atherogenic lipid triad, consisting of an increase in small dense low density lipoprotein particles and in triglyceride-rich lipoproteins, and a decrease in high-density lipoprotein cholesterol, with an increase in non-HDL cholesterol. Numerous trials have investigated the efficacy of add-on ezetimibe therapy for patients with type 2 diabetes and not controlled by statin therapy. The published data highly suggest that patients with type 2 diabetes may be more likely to benefit from ezetimibe/statin combination therapy. However, evidence specifically addressing hard clinical endpoints and prospective trials addressing differences in response between patients with or without diabetes are still needed.

Postprandial Dysmetabolism and Oxidative Stress in Type 2 Diabetes: Pathogenetic Mechanisms and Therapeutic Strategies

Postprandial dysmetabolism in type 2 diabetes (T2D) is known to impact the progression and evolution of this complex disease process. However, the underlying pathogenetic mechanisms still require full elucidation to provide guidance for disease prevention and treatment. This review focuses on the marked redox changes and inflammatory stimuli provoked by the spike in blood glucose and lipids in T2D individuals after meals. All the causes of exacerbated postprandial oxidative stress in T2D were analyzed, also considering the consequence of enhanced inflammation on vascular damage. Based on this in-depth analysis, current strategies of prevention and pharmacologic management of T2D were critically reexamined with particular emphasis on their potential redox-related rationale.

Ezetimibe stimulates intestinal glucagon-like peptide 1 secretion via the MEK/ERK pathway rather than dipeptidyl peptidase 4 inhibition

OBJECTIVE

Ezetimibe is known as a Niemann-Pick C1-Like 1 (NPC1L1) inhibitor and has been used as an agent for hypercholesterolemia. In our previous study, ezetimibe administration improved glycemic control and increased glucagon like peptide-1 (GLP-1), an incretin hormone with anti-diabetic properties. However, the mechanisms by which ezetimibe stimulates GLP-1 secretion are not fully understood. Thus, the specific aim of this study was to investigate the mechanism(s) by which ezetimibe stimulates GLP-1 secretion.

MATERIALS/METHODS

Male KK/H1J mice were divided into following groups: AIN-93G (NC), NC with ezetimibe (10 mg/kg/day), 45% high fat (HF) diet, and HF diet with ezetimibe. To investigate the role of ezetimibe in glucose homeostasis and GLP-1 secretion, an insulin tolerance test was performed and serum and intestinal GLP-1 levels and intestinal mRNA expression involved in GLP-1 synthesis were measured after 6 weeks of ezetimibe treatment. In vivo and in vitro dipeptidyl peptidase-4 (DPP-4) inhibition assays were employed to demonstrate the association between ezetimibe-induced GLP-1 change and DPP-4. The molecular mechanism by which ezetimibe affects GLP-1 secretion was evaluated by using human enteroendocrine NCI-H716 cells.

RESULTS

Ezetimibe supplementation significantly ameliorated HF-increased glucose and insulin resistance in the type 2 diabetic KK/H1J mouse model. Serum and intestinal active GLP-1 levels were significantly increased by ezetimibe in HF-fed animals. However, mRNA expression of genes involved in intestinal GLP-1 synthesis was not altered. Furthermore, ezetimibe did not inhibit the activity of either in vivo or in vitro dipeptidyl peptidase-4 (DPP-4). The direct effects of ezetimibe on GLP-1 secretion and L cell secretory mechanisms were examined in human NCI-H716 intestinal cells. Ezetimibe significantly stimulated active GLP-1 secretion, which was accompanied by the activation of mitogen-activated protein/extracellular signal-regulated kinase kinase (MEK)/extracellular signal-regulated kinase (ERK). Ezetimibe-increased GLP-1 secretion was abrogated by inhibiting the MEK/ERK pathway with PD98059.

CONCLUSION

These findings suggest a possible novel biological role of ezetimibe in glycemic control to stimulate intestinal GLP-1 secretion via the MEK/ERK signaling pathway.

A randomized, double-blind, placebo-controlled study of the effect of ezetimibe on glucose metabolism in subjects with type 2 diabetes mellitus and hypercholesterolemia

Background

Recent evidence points to an increased incidence of new-onset diabetes and a negative impact on glucose parameters with statin use. This study examined the safety of ezetimibe vs placebo for change from baseline to week 24 in HbA1c (primary endpoint), glycoalbumin, and fasting plasma glucose (secondary endpoints) in Japanese subjects with type 2 diabetes and hypercholesterolemia.

Methods

This was a randomized, double-blind, placebo-controlled, parallel-group, multi-site trial. Adults with type 2 diabetes and hypercholesterolemia whose LDL-C measured <140 mg/dl (subjects receiving lipid-lowering drugs) or <160 mg/dl (subjects not receiving lipid-lowering drugs) at the start of the screening phase, were randomized after a 5-week wash-out period to ezetimibe 10 mg or placebo (1:1) for 24 weeks. Changes in HbA1c, glycoalbumin and fasting plasma glucose from baseline to week 24 were evaluated. The non-inferiority margin was set at 0.5% for HbA1c.

Results

Overall, 152 subjects were randomized (75 to ezetimibe and 77 to placebo). From baseline to 24 weeks, HbA1c significantly increased in both the ezetimibe and placebo groups (between-treatment difference 0.08 [95% CI: −0.07 to 0.23]). Ezetimibe was statistically non-inferior to placebo. At 24 weeks, the mean change from baseline in glycoalbumin levels (between-treatment differences 0.00 [95% CI: −0.47, 0.47]) and fasting plasma glucose (between-treatment differences −4.8 [95% CI: −12.1, 2.1]) were similar in both treatment groups.

Conclusions

These results suggest that ezetimibe 10 mg does not result in dysregulation of glucose metabolism in Japanese patients with type 2 diabetes and hypercholesterolemia over 24 weeks of treatment.

Trial registration

ClinicalTrials.gov identifier NCT01611883.

Electronic supplementary material

The online version of this article (doi:10.1186/s12944-015-0036-z) contains supplementary material, which is available to authorized users.

Ezetimibe ameliorates atherogenic lipids profiles, insulin resistance and hepatocyte growth factor in obese patients with hypercholesterolemia

Background

Ezetimibe ameliorates serum low-density lipoprotein cholesterol (LDL-c) and it has been approved for the treatment of hypercholesterolemia. However, the effects of ezetimibe on specific biomarkers have not been fully clarified in obese Japanese patients.

Methods

A total of 101 patients (47 males and 54 females) were registered in this study during 2011 and 2012. All patients were over 20 years old, were obese [body mass index (BMI) ≥ 25kg/m²] and had hypercholesterolemia (LDL-c ≥ 120mg/dl). After excluding 10 subjects (7 who dropped out and 3 with missing data), 91 patients (39 males and 52 females) were analyzed. They were treated with 10 mg ezetimibe once a day for 24 weeks and were evaluated at 12 and 24 weeks.

Results

Following 12 weeks of ezetimibe therapy, BMI (p < 0.001), waist circumference (p < 0.001), total cholesterol (p < 0.001), LDL-c (p < 0.001), non high-density lipoprotein cholesterol [HDL-c] (p < 0.001), triglycerides (p < 0.05) and remnant-like particle cholesterol (RLP-c; p < 0.001) were significantly decreased. Following 24 weeks of ezetimibe therapy, BMI (p < 0.05), waist circumference (p < 0.001), total cholesterol (p < 0.001), LDL-c (p < 0.001), non HDL-c (p < 0.001), triglycerides (p < 0.05), RLP-c (p < 0.001), insulin (p < 0.05) and hepatocyte growth factor (HGF; p < 0.05) were significantly decreased. In contrast, HDL-c (p < 0.001) was significantly increased.

Conclusions

Ezetimibe ameliorated not only atherogenic lipid profiles but also anthropometric factors, insulin resistance and biomarkers such as HGF. Ezetimibe may have pleiotropic effects on obese patients with hypercholesterolemia.

Ezetimibe combined with standard diet and exercise therapy improves insulin resistance and atherosclerotic markers in patients with metabolic syndrome

Aims/Introduction

Ezetimibe lowers serum lipid levels by inhibiting intestinal absorption of dietary and biliary cholesterol. However, the effect of ezetimibe on insulin resistance remains unclear. The aim of the present study was to examine this issue in patients with metabolic syndrome in local-dwelling Japanese, who were not being treated with lipid-lowering drugs.

Materials and Methods

In 2009, 1,943 participants received a health examination in the Tanushimaru Study, a Japanese cohort of the Seven Countries Study, of whom 490 participants had metabolic syndrome. Among them, 61 participants (41 men and 20 women) were examined in the present study. They were treated with 10 mg of ezetimibe once a day for 24 weeks, combined with standard diet and exercise therapy.

Results

Bodyweight (P < 0.001), body mass index (P < 0.001), systolic blood pressure (P = 0.003), diastolic blood pressure (P < 0.001), triglycerides (P = 0.002), non-high-density lipoprotein cholesterol (P = 0.001), low-density lipoprotein cholesterol (P < 0.001) and homeostasis model assessment of insulin resistance (P = 0.011) significantly decreased after the observational period. There were no statistically significant differences in the effects of ezetimibe between men and women. Univariate analysis showed that the reduction of homeostasis model assessment of insulin resistance was not associated with the improvement of other metabolic components.

Conclusions

Ezetimibe combined with standard diet and exercise therapy improves not only bodyweight and atherogenic lipid profiles, but also insulin resistance, blood pressure and anthropometric factors in metabolic syndrome in local-dwelling Japanese. Interestingly, the improvement of insulin resistance had no correlation with other metabolic components.

Postprandial lipemia as a cardiometabolic risk factor

High levels of fasting circulating triglycerides (TG) represent an independent risk factor for cardiovascular disease. In western countries, however, people spend most time in postprandial conditions, with continuous fluctuation of lipemia due to increased levels of TG-rich lipoproteins (TRLs), including chylomicrons (CM), very low density lipoproteins (VLDL), and their remnants. Several factors contribute to postprandial lipid metabolism, including dietary, physiological, pathological and genetic factors. The presence of coronary heart disease, type 2 diabetes, insulin resistance and obesity is associated with higher postprandial TG levels compared with healthy conditions; this association is present also in subjects with normal fasting TG levels. Increasing evidence indicates that impaired metabolism of postprandial lipoproteins contributes to the pathogenesis of coronary artery disease, suggesting that lifestyle modifications as well as pharmacological approaches aimed at reducing postprandial TG levels might help to decrease the cardiovascular risk.

Origin and therapy for hypertriglyceridaemia in type 2 diabetes

Hypertriglyceridaemia (HTG) is a risk factor for cardiovascular disease (CVD) in type 2 diabetes and is caused by the interaction of genes and non-genetic factors, specifically poor glycaemic control and obesity. In spite of statin treatment, residual risk of CVD remains high in type 2 diabetes, and this may relate to HTG and atherogenic dyslipidemia. Treatment of HTG emphasises correcting secondary factors and adverse lifestyles, in particular, diet and exercise. Pharmacotherapy is also required in most type 2 diabetic patients. Statins are the first-line therapy to achieve recommended therapeutic targets of plasma low-density lipoprotein cholesterol and non-high-density lipoprotein cholesterol. Fibrates, ezetimibe and n-3 fatty acids are adjunctive treatment options for residual and persistent HTG. Evidence for the use of niacin has been challenged by non-significant CVD outcomes in two recent large clinical trials. Further investigation is required to clarify the use of incretin-based therapies for HTG in type 2 diabetes. Extreme HTG, with risk of pancreatitis, may require insulin infusion therapy or apheresis. New therapies targeting HTG in diabetes need to be tested in clinical endpoint trials. The purpose of this review is to examine the current evidence and provide practical guidance on the management of HTG in type 2 diabetes.

New and emerging regulators of intestinal lipoprotein secretion

Overproduction of hepatic apoB100-containing VLDL particles has been well documented in animal models and in humans with insulin resistance such as the metabolic syndrome and type 2 diabetes, and contributes to the typical dyslipidemia of these conditions. In addition, postprandial hyperlipidemia and elevated plasma concentrations of intestinal apoB48-containing chylomicron and chylomicron remnant particles have been demonstrated in insulin resistant states. Intestinal lipoprotein production is primarily determined by the amount of fat ingested and absorbed. Until approximately 10 years ago, however, relatively little attention was paid to the role of the intestine itself in regulating the production of triglyceride-rich lipoproteins (TRL) and its dysregulation in pathological states such as insulin resistance. We and others have shown that insulin resistant animal models and humans are characterized by overproduction of intestinal apoB48-containing lipoproteins. Whereas various factors are known to regulate hepatic lipoprotein particle production, less is known about factors that regulate the production of intestinal lipoprotein particles. Monosacharides, plasma free fatty acids (FFA), resveratrol, intestinal peptides (e.g. GLP-1 and GLP-2), and pancreatic hormones (e.g. insulin) have recently been shown to be important regulators of intestinal lipoprotein secretion. Available evidence in humans and animal models strongly supports the concept that the small intestine is not merely an absorptive organ but rather plays an active role in regulating the rate of production of chylomicrons in fed and fasting states. Metabolic signals in insulin resistance and type 2 diabetes and in some cases an aberrant intestinal response to these factors contribute to the enhanced formation and secretion of TRL. Understanding the regulation of intestinal lipoprotein production is imperative for the development of new therapeutic strategies for the prevention and treatment of dyslipidemia. Here we review recent developments in this field and present evidence that intestinal lipoprotein production is a process with metabolic plasticity and that modulation of intestinal lipoprotein secretion may be a feasible therapeutic strategy in the treatment of dyslipidemia and possibly prevention of atherosclerosis.

Evaluation of hypertriglyceridemia using non-fasting health checkup data in a Japanese population

AIM

Some employees have difficulty undergoing health checkups in the workplace in a fasting state. However, hypertriglyceridemia is usually diagnosed based on fasting triglyceride (TG) measurements. The current study investigated the performance of non-fasting health checkup data for predicting hypertriglyceridemia in a Japanese population.

METHODS

We recruited a total of 1,959 Japanese employees who had their fasting TG levels reexamined after undergoing initial health checkups under either a fasting (the fasting population; n= 856) or non-fasting state (the non-fasting population; n= 1103). Hypertriglyceridemia was defined as a fasting TG level of ≥ 1.7 mmol/l.

RESULTS

The area under the receiver operating characteristic (ROC) curve of the initial TG measurements for reexamination-detected hypertriglyceridemia was 0.85 in the fasting population and 0.83 in the non-fasting population. The area under the ROC curve of the initial TG measurements in the non-fasting population was not inferior to that of the multivariate model where other non-fasting health checkup data were added. The optimal non-fasting TG cutoff point was 2.0 mmol/l. The cutoff point was further lowered when the population was limited to patients undergoing health checkups four or more hours after their last meal and when the prevalence of hypertriglyceridemia in the population was simulated to be reduced.

CONCLUSIONS

The non-fasting workplace TG measurements by themselves exhibited a tolerable performance for predicting hypertriglyceridemia. The optimal cutoff point in Japanese employees appears to be lower than 2.3 mmol/l, the recently proposed Western cutoff point.

Effect of ezetimibe on insulin secretion in db/db diabetic mice

OBJECTIVE

To investigate the effect of ezetimibe on the insulin secretion in db/db mice.

METHODS

The db/db diabetic mice aged 8 weeks were randomly assigned into 2 groups and intragastrically treated with ezetimibe or placebo for 6 weeks. The age matched db/m mice served as controls. At the end of experiment, glucose tolerance test was performed and then the pancreas was collected for immunohistochemistry. In addition, in vitro perfusion of pancreatic islets was employed for the detection of insulin secretion in the first phase.

RESULTS

In the ezetimibe group, the fasting blood glucose was markedly reduced, and the total cholesterol (TC) and low-density lipoprotein cholesterol (LDL-C) were significantly lowered when compared with those in the control group (P < 0.05). At 120 min after glucose tolerance test, the area under curve in the ezetimibe group was significantly smaller than that in the control group (P < 0.05), but the AUC(INS0-30) was markedly higher. In vitro perfusion of pancreatic islets revealed the first phase insulin secretion was improved. In addition, the insulin expression in the pancreas in the ezetimibe group was significantly increased as compared to the control group.

CONCLUSION

Ezetimibe can improve glucose tolerance, recover the first phase insulin secretion, and protect the function of β cells in mice.