Lipid metabolism disorder promotes the development of intervertebral disc degeneration

Lipid metabolism is a complex process that maintains the normal physiological function of the human body. The disorder of lipid metabolism has been implicated in various human diseases, such as cardiovascular diseases and bone diseases. Intervertebral disc degeneration (IDD), an age-related degenerative disease in the musculoskeletal system, is characterized by high morbidity, high treatment cost, and chronic recurrence. Lipid metabolism disorder may promote the pathogenesis of IDD, and the potential mechanisms are complex. Leptin, resistin, nicotinamide phosphoribosyltransferase (NAMPT), fatty acids, and cholesterol may promote the pathogenesis of IDD, while lipocalin, adiponectin, and progranulin (PGRN) exhibit protective activity against IDD development. Lipid metabolism disorder contributes to extracellular matrix (ECM) degradation, cell apoptosis, and cartilage calcification in the intervertebral discs (IVDs) by activating inflammatory responses, endoplasmic reticulum (ER) stress, and oxidative stress and inhibiting autophagy. Several lines of agents have been developed to target lipid metabolism disorder. Inhibition of lipid metabolism disorder may be an effective strategy for the therapeutic management of IDD. However, an in-depth understanding of the molecular mechanism of lipid metabolism disorder in promoting IDD development is still needed.

Effect of cholesterol-lowering agents on soluble epidermal growth factor receptor level in type 2 diabetes and hypercholesterolemia

Soluble epidermal growth factor receptor (sEGFR) levels are elevated in patients with type 2 diabetes mellitus (T2DM) and positively correlate with blood glucose and cholesterol levels. However, how cholesterol-lowering treatment in patients with T2DM affects the sEGFR level is unknown. Therefore, we investigated the change of serum sEGFR after cholesterol-lowering treatment in type 2 diabetic patients with hypercholesterolemia. This study is a non-randomized, prospective observational study. A total of 115 patients were treated in either the rosuvastatin monotherapy group (R group, 5 mg/day, n = 59) or the rosuvastatin/ezetimibe combination therapy group (RE group, 5 mg/10 mg/day, n = 56) for 12 weeks. We measured serum levels of lipids and sEGFR using an ELISA kit before and after 12 weeks of treatment in each group. The low-density lipoprotein cholesterol (LDL-C) level was significantly reduced (from 130.27 ± 27.09 to 76.24 ± 26.82 mg/dL; P < .001) after 12 weeks of treatment and more so in the RE group than in the R group (from 131.68 ± 28.72 to 87.13 ± 27.04 mg/dL, P < .001 in the R group; from 128.78 ± 25.58 to 64.75 ± 21.52 mg/dL, P < .001 in the RE group; R vs RE group, P < .001). The sEGFR level was significantly decreased after 12 weeks of treatment (from 50.34 ± 13.31 to 45.75 ± 11.54 ng/mL; P = .007). The RE group only showed a significant reduction in the sEGFR level after treatment (from 50.94 ± 12.10 to 44.80 ± 11.36 ng/mL; P = .007). Moreover, the sEGFR level was significantly reduced only when the LDL-C level was significantly reduced (from 50.46 ± 10.66 to 46.24 ± 11.86 ng/mL; P = .043). The serum sEGFR level was significantly reduced by cholesterol-lowering treatment with rosuvastatin alone or rosuvastatin/ezetimibe. We suggested that sEGFR may play a significant role in insulin resistance (IR) and inflammation, which are central pathophysiological mechanisms. We confirmed the possibility of using sEGFR as a biomarker to predict a good response to lipid-lowering treatment in type 2 diabetes patients with hypercholesterolemia.

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.

Serum MIG6 concentration is increased by cholesterol-lowering treatment in patients with type 2 diabetes mellitus and hypercholesterolemia

Objective

The protein encoded by mitogen-inducible gene 6 (MIG6) plays an essential role in the regulation of cholesterol homeostasis and bile acid synthesis in mice. However, the physiological functions of MIG6 remain poorly understood in humans. Therefore, we aimed to evaluate the relationship between the serum MIG6 concentration and low-density lipoprotein (LDL)-cholesterol in patients undergoing cholesterol-lowering treatment.

Methods

We performed a non-randomized, prospective controlled trial. In total, 63 patients with type 2 diabetes and hypercholesterolemia were treated using either rosuvastatin monotherapy or rosuvastatin/ezetimibe combination therapy for 12 weeks. We then compared their serum lipid and MIG6 concentrations before and after treatment.

Results

The serum LDL-cholesterol concentration of the participants significantly decreased and the concentration of MIG6 significantly increased during treatment. In addition, higher pre-treatment serum concentrations of MIG6 were associated with larger reductions in LDL-cholesterol, regardless of the therapeutic agent used.

Conclusions

Serum MIG6 concentration significantly increases alongside the reduction in LDL-cholesterol achieved using cholesterol-lowering therapies in patients with diabetes and hypercholesterolemia. This is the first study to provide evidence that MIG6 may be involved in human cholesterol metabolism.

CRIS registration number: KCT0003477. https://cris.nih.go.kr.

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 Monotherapy on Low-Density Lipoprotein Cholesterol and on Markers of Cholesterol Synthesis and Absorption in Japanese Patients With Hypercholesterolemia

Background

The aim of this study was to evaluate effect of ezetimibe monotherapy on serum low-density lipoprotein cholesterol (LDL-C) in Japanese patients and to investigate the association between changes of LDL-C and changes of markers for cholesterol synthesis and absorption.

Methods

Seventy-six hypercholesterolemic patients without statin therapy were enrolled and randomized to two groups, which were an ezetimibe group (group E, n = 44) and a control group without ezetimibe treatment that received diet therapy alone (group C, n = 32). The study period was 12 weeks. In group E, 10 mg of ezetimibe was administered daily after breakfast. Serum lipids were measured every 4 weeks, while lathosterol (a cholesterol synthesis marker) and campesterol and sitosterol (cholesterol absorption markers) were examined at baseline and at 12 weeks.

Results

A significant reduction of LDL-C was observed in group E at both 4 and 12 weeks (from 155 ± 3.9 to 128 ± 3.4 mg/dL and 132 ± 3.9 mg/dL, respectively, both P < 0.01), associated with an increase of high-density lipoprotein cholesterol (HDL-C)at 12 weeks (from 53 ± 1.3 to 55 ± 1.5 mg/dL, P < 0.05) and no change of triglycerides. In contrast, none of these lipids changed in group C. An increase of lathosterol and a decrease of campesterol and sitosterol were observed in group E, while none of these markers changed in group C. When group E was divided into two subgroups according to the reduction of LDL-C, which were a good response group (reduction ≥ 20 mg/dL, ΔLDL-C = -27.9 ± 1.3 mg/dL, n = 18) and a poor response group (reduction < 20 mg/dL, ΔLDL-C = -3.7 ± 2.5 mg/dL, n = 26), baseline levels of campesterol and sitosterol were higher in the good response group.

Conclusion

Ezetimibe monotherapy reduced LDL-C and increased HDL-C, with the reduction of LDL-C being greater in patients with higher levels of cholesterol absorption markers.

The value of surrogate markers to monitor cholesterol absorption, synthesis and bioconversion to bile acids under lipid lowering therapies

INTRODUCTION

Regulation of cholesterol (Chol) homeostasis is controlled by three main fluxes, i.e. intestinal absorption, de novo synthesis (ChS) and catabolism, predominantly as bile acid synthesis (BAS). High serum total Chol and LDL-Chol concentrations in particular are considered risk factors and markers for the development of atherosclerosis. Pharmaceutical treatments to lower serum Chol have focused on reducing absorption or ChS and increasing BAS. Monitoring of these three parameters is complex involving isotope techniques, cholesterol balance experiments and advanced mass spectrometry based analysis methods. Surrogate markers were explored that require only one single fasting blood sample collection. These markers were validated in specific, mostly physiological conditions and during statin treatment to inhibit ChS. They were also applied under cholesterol absorption restriction, but were not validated in this condition. We retrospectively evaluated the use of serum campesterol (Camp), sitosterol (Sit) and cholestanol (Cholol) as markers for cholesterol absorption, lathosterol (Lath) as marker for ChS and 7α-hydroxycholesterol (7α-OH-Ch) and 27-hydroxycholesterol (27-OH-Ch) as markers for BAS under conditions of Chol absorption restriction. Additionally, their values were corrected for Chol concentration (R_sterol or oxysterols).

METHODS

Thirty-seven healthy male omnivore subjects were studied under treatments with placebo (PLAC), ezetimibe (EZE) to inhibit cholesterol absorption, simvastatin (SIMVA) to reduce cholesterol synthesis and a combination of both (EZE+SIMVA). Results were compared to those obtained in 18 pure vegetarian subjects (vegans) whose dietary Chol intake is extremely low. Relative or fractional Chol absorption (FrChA) was measured with the continuous feeding stable isotope procedure, ChS and BAS with the cholesterol balance method. The daily Chol intake (DICh) was inventoried and the daily Chol absorption (DACh) calculated.

RESULTS

Monitoring cholesterol absorption, R_Camp, R_Sit and R_Cholol responded sensitively to changes in FrChA. R_Camp correlated well with FrChA in all omnivore treatment groups and in the vegan group. R_Camp confirmed reduced FrChA under EZE treatment and reduced DACh in the vegan subjects. R_Sit and R_Cholol did not accurately reflect FrChA or DACh in all situations. Monitoring endogenous cholesterol synthesis, R_Lath correlated with ChS in the vegan group, but in none of the omnivore treatment groups. R_Lath confirmed increased ChS under EZE treatment and was reduced under SIMVA treatment, while ChS was not. An increased ChS under EZE+SIMVA treatment could not be confirmed with R_Lath. R_Lath responded very insensitively to a change in ChS. Monitoring BAS, R_7α-OH-Ch but not R_27-OH-Ch correlated with BAS during PLAC, EZE and SIMVA treatments. In line with BAS, R_7α-OH-Ch did not differ in any of the omnivore treatment groups. R_7α-OH-Ch responded insensitively to a change in BAS.

CONCLUSIONS

Under Chol absorption restriction, serum R_Camp is a sensitive and valid marker to monitor FrChA in a population with a normal DICh. Also, major changes in DACh can be detected in vegans. Serum R_Lath does not reflect ChS measured with the cholesterol balance method during EZE treatment. This result initiates the question whether the measured ChS reflects pure de novo synthesis. Serum R_7α-OH-Ch appears to be a valid but insensitive marker for BAS.

Effects of a diet rich in arabinoxylan and resistant starch compared with a diet rich in refined carbohydrates on postprandial metabolism and features of the metabolic syndrome

PURPOSE

Low intake of dietary fibre is associated with the development of type 2 diabetes. Dyslipidaemia plays a key role in the pathogenesis of type 2 diabetes. Knowledge of the impact of dietary fibres on postprandial lipaemia is, however, sparse. This study aimed in subjects with metabolic syndrome to assess the impact on postprandial lipaemia and features of the metabolic syndrome of a healthy carbohydrate diet (HCD) rich in cereal fibre, arabinoxylan and resistant starch compared to a refined-carbohydrate western-style diet (WSD).

METHODS

Nineteen subjects completed the randomised, crossover study with HCD and WCD for 4-week. Postprandial metabolism was evaluated by a meal-challenge test and insulin sensitivity was assessed by HOMA-IR and Matsuda index. Furthermore, fasting cholesterols, serum-fructosamine, circulating inflammatory markers, ambulatory blood pressure and intrahepatic lipid content were measured.

RESULTS

We found no diet effects on postprandial lipaemia. However, there was a significant diet × statin interaction on total cholesterol (P = 0.02) and LDL cholesterol (P = 0.002). HCD decreased total cholesterol (-0.72 mmol/l, 95% CI (-1.29; -0.14) P = 0.03) and LDL cholesterol (-0.61 mmol/l, 95% CI (-0.86; -0.36) P = 0.002) compared with WSD in subjects on but not without statin treatment. We detected no other significant diet effects.

CONCLUSIONS

In subjects with metabolic syndrome on statins a 4-week diet rich in arabinoxylan and resistant starch improved fasting LDL and total cholesterol compared to subjects not being on statins. However, we observed no diet related impact on postprandial lipaemia or features of the metabolic syndrome. The dietary fibre x statin interaction deserves further elucidation.

Effect on Fasting Serum Glucose Levels of Adding Ezetimibe to Statins in Patients With Nondiabetic Hypercholesterolemia

Statin therapy is associated with a slightly increased risk of developing diabetes mellitus and insulin resistance in patients without diabetes. Ezetimibe combined with statins may be considered for high-risk patients who do not achieve optimal low-density lipoprotein cholesterol lowering on statin monotherapy or who are statin intolerant. Changes in fasting serum glucose (FSG) levels during ezetimibe, ezetimibe/statin, and statin treatments were assessed using data pooled from clinical trials in hypercholesterolemic and heterozygous familial hypercholesterolemic patients, who were or were not receiving statin therapy. Study types included first-line trials in statin-naive/wash-out patients and second-line add-on and uptitration studies in patients on stable statin therapy. Similar analyses of FSG changes were performed separately for each study type in patients who were nondiabetic at baseline. Across all study types and treatments, mean FSG increases from baseline were small (0.5 to 3.7 mg/dl with ezetimibe/statin; 0.2 to 4.6 mg/dl with statins) and decreased over time; between-treatment differences (0.3 to 1.4 mg/dl) were nonsignificant for all comparisons. Proportions of patients with elevated FSG ≥126 mg/dl during therapy were low and similar for all treatments in the overall cohort (1.2% to 4.3%). Elevations were highest (3.3% to 25.7%) among patients with baseline factors characteristic of metabolic syndrome and prediabetes, including higher FSG, body mass index, and triglyceride levels, and numerically lower baseline high-density lipoprotein cholesterol; however, these factors were not related to FSG increases. Changes in low-density lipoprotein cholesterol, body mass index, high-density lipoprotein cholesterol, triglycerides, and apolipoprotein B were not significantly correlated with FSG increases. In conclusion, statin therapy was associated with small FSG increases, and the addition of ezetimibe did not further increase FSG levels beyond those of statins when given to patients who are statin naive or those on statin therapy.

Long-term administration of a Niemann-Pick C1-like 1 inhibitor, ezetimibe, does not worsen bile lithogenicity in dyslipidemic patients with hepatobiliary diseases

BACKGROUND

Certain lipid-lowering drugs increase bile lithogenicity. Here we investigated whether long-term administration of ezetimibe, a new class of hypocholesterolemic agents designed to inhibit intestinal cholesterol absorption by inhibiting Niemann-Pick C1-like 1, alters bile lithogenicity in patients with hepatobiliary diseases.

METHODS

Eleven dyslipidemic patients with gallstones and/or fatty liver diseases were treated with ezetimibe (10 mg/day) for 12 months. Bile samples were collected by nasal endoscopy before and after 3 and 12 months of treatment. Serum and bile lipids and serum metabolic parameters were analyzed.

RESULTS

Serum levels of campesterol, total cholesterol, and low-density lipoprotein cholesterol were significantly decreased after 3 and 12 months of treatment. In contrast, serum lathosterol levels increased gradually. The lithogenic index of bile was unsaturated and unchanged in patients who were previously and concomitantly receiving ursodeoxycholic acid (UDCA). In patients who were not receiving UDCA, bile was initially supersaturated, but eventually was unsaturated. However, ezetimibe tended to elevate bile lithogenicity in cholecystectomy patients.

CONCLUSIONS

Long-term treatment with ezetimibe improves lipid metabolism without significantly altering the bile lithogenicity. Therefore, inhibiting intestinal cholesterol absorption in dyslipidemic patients with hepatobiliary diseases is a safe therapeutic strategy without worsening biliary physiology.

The usefulness of a cholesterol absorption inhibitor in Japanese type 2 diabetes patients with dyslipidemia

AIM

Cholesterol absorption has been suggested to be an independent risk factor for cerebral and cardiovascular events. We studied the clinical efficacy of ezetimibe in Japanese patients with type 2 diabetes mellitus complicated by dyslipidemia, in whom increased cholesterol absorption had been reported.

SUBJECTS AND METHODS

Ninety-six patients with type 2 diabetes complicated by dyslipidemia received ezetimibe at 10 mg/day for 12 weeks. The lipid profile, a cholesterol synthesis marker (lathosterol), and cholesterol absorption markers (cholestanol, sitosterol, and campesterol) were measured before and after the therapy to evaluate the clinical efficacy of ezetimibe.

RESULTS

Serum low-density lipoprotein-cholesterol (LDL-C) levels were positively associated with cholesterol absorption markers but not associated with a cholesterol synthesis marker, suggesting that serum LDL-C levels are more strongly related to cholesterol absorption than synthesis. During the 12-week ezetimibe treatment period, cholesterol absorption markers significantly decreased, and serum lipid profiles, including LDL-C levels, significantly improved. The LDL-C-lowering rate was greater in those patients who had been receiving statin therapy and were newly started on ezetimibe additionally than in the ezetimibe monotherapy group (-31.4% vs. -18.4%; P<0.001).

CONCLUSIONS

It is suggested that ezetimibe improves the lipid profile in Japanese type 2 diabetes patients with dyslipidemia through the substantial reduction of cholesterol absorption.

Clinical evaluation of ezetimibe on bile lithogenicity in humans: Use of transnasal endoscopy for bile sampling

AIM

Ezetimibe inhibits cholesterol absorption by blocking Niemann-Pick C1-like 1 proteins (NPC1L1) expressed in the small intestine. Because NPC1L1 is also expressed in human liver, ezetimibe conceivably alters biliary lipid compositions. Here, we performed a clinical trial investigating the effect of ezetimibe on biliary lipids using transnasal endoscopy for bile collection.

METHODS

Eight patients with dyslipidemia enrolled in this study completed blood and bile sampling before and at 3 months after ezetimibe treatment (10 mg/day), and the samples are analyzed.

RESULTS

Endoscopic bile sampling was performed safely and painlessly. Serum sterol-based biomarkers declared decreased cholesterol absorption and increased synthesis. On analysis of biliary lipids, four of the eight patients showed relative decrease of cholesterol and increase of bile acids with improved lithogenicity while the remainder exhibited the symmetrical changes.

CONCLUSION

Our data suggests that biliary lithogenicity is not worsened by ezetimibe. The regulation of biliary cholesterol is presumably multifactorial such as body cholesterol pool size and biliary cholesterol reabsorption by NPC1L1 in the liver.

Hepatic NPC1L1 overexpression ameliorates glucose metabolism in diabetic mice via suppression of gluconeogenesis

OBJECTIVE

Inhibition of intestinal NPC1L1 by ezetimibe has been demonstrated to improve glucose metabolism in rodent models; however, the role of hepatic NPC1L1 in glucose metabolism has not been elucidated. In this study, we analyzed the effects of hepatic NPC1L1 on glucose metabolism.

MATERIAL AND METHODS

We overexpressed NPC1L1 in the livers of lean wild type mice, diet-induced obesity mice and db/db mice with adenoviral gene transfer.

RESULTS

We found that in all three mouse models, hepatic NPC1L1 overexpression lowered fasting blood glucose levels as well as blood glucose levels on ad libitum; in db/db mice, hepatic NPC1L1 overexpression improved blood glucose levels to almost the same as those found in lean wild type mice. A pyruvate tolerance test revealed that gluconeogenesis was suppressed by hepatic NPC1L1 overexpression. Further analyses revealed that hepatic NPC1L1 overexpression decreased the expression of FoxO1, resulting in the reduced expression of G6Pase and PEPCK, key enzymes in gluconeogenesis.

CONCLUSIONS

These results indicate that hepatic NPC1L1 might have distinct properties of suppressing gluconeogenesis via inhibition of FoxO1 pathways.

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.

Effects of ezetimibe on cholesterol metabolism in HIV-infected patients with protease inhibitor-associated dyslipidemia: a single-arm intervention trial

Background

The effects of ezetimibe on cholesterol metabolism in HIV-infected patients receiving boosted protease inhibitors have not been thoroughly assessed. The aim of this study was to assess cholesterol homeostasis in patients with PI associated dyslipidemia and its relationship with the response to treatment with the cholesterol-absorption inhibitor ezetimibe.

Methods

Fifteen patients with ritonavir-boosted PI-containig therapy and LDL-cholesterol > 3.36 mmol/L (>130 mg/dL) were assessed at baseline and after an 8-week course of ezetimibe 10 mg/d. Serum non-cholesterol sterols were measured at each visit as markers of cholesterol synthesis and absorption. Total-, LDL-, and HDL-cholesterol triglycerides, apolipoproteins A1 and B, high sensitivity C-reactive protein, CD4 cells and HIV-1 RNA were also measured.

Results

Ezetimibe treatment was well tolerated in all patients and resulted in significant reductions in total cholesterol (-11.4%, p = .002), LDL-cholesterol (-20.4%, p = .003), non-HDL-cholesterol (-13.4%, p = .002) and apolipoprotein B (-9.1%, p = .021).

Treatment with ezetimibe was associated with decreased cholesterol absorption markers (campesterol-to-cholesterol ratio -43.0%, p = .001; sitosterol-to-cholesterol ratio -41.9%, p = .001) and increased synthesis markers (lathosterol-to-cholesterol ratio 53.2%, p = .005). Baseline absorption or synthesis markers were unrelated to the response to treatment. CD4 cell count and plasma HIV-1 RNA remained unchanged.

Conclusions

The level of cholesterol absorption or synthesis does not appear to be a major determinant of the responsiveness to ezetimibe in patients on ritonavir-boosted PI-containing therapy.

Trial registration

EudraCT: 2006-006156-36

Electronic supplementary material

The online version of this article (doi:10.1186/1471-2334-14-497) contains supplementary material, which is available to authorized users.

The Niemann-Pick C1 like 1 (NPC1L1) inhibitor ezetimibe improves metabolic disease via decreased liver X receptor (LXR) activity in liver of obese male mice

Dyslipidemic patients with diabetes mellitus, including metabolic syndrome, are at increased risk of coronary heart disease. It has been reported that ezetimibe, a cholesterol absorption inhibitor, improves metabolic diseases in mice and humans. However, the underlying mechanism has been unclear. Here we explored the effects of ezetimibe on lipid and glucose homeostasis. Male KK-A(y) mice were fed a high-fat diet, which is the mouse model of metabolic syndrome, with or without ezetimibe for 14 weeks. Ezetimibe improved dyslipidemia, steatosis, and insulin resistance. Ezetimibe decreased hepatic oxysterols, which are endogenous agonists of liver X receptor (LXR), to decrease hepatic lipogenic gene expressions, especially in stearoyl-CoA desaturase-1 (SCD1), leading to a remarkable reduction of hepatic oleate content that would contribute to the improvement of steatosis by reducing triglycerides and cholesterol esters. Simultaneously, hepatic β-oxidation, NADPH oxidase and cytochrome P450 2E1 (CYP2E1) were reduced, and thus reactive oxygen species (ROS) and inflammatory cytokines were also decreased. Consistent with these changes, ezetimibe diminished c-Jun N-terminal kinase (JNK) phosphorylation and improved insulin signaling in the liver. In vitro study using primary hepatocytes obtained from male SD rats, treated with oleate and LXR agonist, showed excess lipid accumulation, increased oxidative stress and impaired insulin signaling. Therefore, in obese subjects, ezetimibe reduces hepatic LXR activity by reducing hepatic oxysterols to lower hepatic oleate content. This improves steatosis and reduces oxidative stress, and this reduction improves insulin signaling in the liver. These results provide insight into pathogenesis and strategies for treatment of the metabolic syndrome.

Coenzyme Q10 ameliorates the reduction in GLUT4 transporter expression induced by simvastatin in 3T3-L1 adipocytes

BACKGROUND

Statins significantly reduce cardiovascular events in a broad population of patients with hyperlipidemia. However, a small, but significant risk of new-onset diabetes has been reported in patients treated with statins. The mechanism by which statins cause diabetes has not been elucidated and therefore preventive strategies have yet to be defined.

METHOD

Our goal was to study the differing effects of a lipophilic (simvastatin) statin, hydrophilic (pravastatin) statin, and ezetimibe on glucose transporter-4 (GLUT4) protein expression in 3T3-L1 adipocytes. We hypothesized that the reductions in GLUT4 protein secondary to statin treatment would be prevented when cells were co-incubated with coenzyme Q10 (CoQ10). GLUT4 protein expression was determined using the In-Cell Western technique. Confluent adipocytes were differentiated using a hormonal cocktail for 3 days; followed by treatment with simvastatin, pravastatin, ezetimibe and CoQ10. Cell morphology was observed after treatment using phase-contrast microscopy.

RESULTS

Treatment with simvastatin (P<0.001) and simvastatin plus ezetimibe (P<0.001) significantly decreased GLUT4 protein expression in the adipocytes compared to control conditions. GLUT4 protein levels were similar to control after treatment with ezetimibe alone (P=0.52) or pravastatin (P=0.32). There was no significant difference (P=0.098) in GLUT4 protein levels after co-treatment with CoQ10 between any of the treatments and control conditions.

CONCLUSION

Our studies have shown that lipophilic statins (simvastatin) reduce the GLUT4 protein levels in adipocytes, whereas hydrophilic statins (pravastatin) or ezetimibe do not. Co-treatment with CoQ10 appears to prevent the reduction in GLUT4 protein levels caused by simvastatin.

Effects of ezetimibe on visceral fat in the metabolic syndrome: a randomised controlled study

BACKGROUND

Although visceral obesity, a key abnormality in the metabolic syndrome, is an important risk for cardiovascular diseases, reduction in visceral fat is hard to achieve despite intensive efforts directed at lifestyle modification. The present study was designed to investigate whether ezetimibe, an inhibitor of intestinal cholesterol absorption through its binding to Niemann-Pick C1-like 1, reduces visceral fat in patients with metabolic syndrome.

MATERIALS AND METHODS

Seventy-eight outpatients (63·7 ± 10·4 years old) with metabolic syndrome were enroled and randomly assigned to receive either ezetimibe (10 mg/day) or nothing for 6 months. Changes in visceral fat were assessed by computed tomography.

RESULTS

Treatment with ezetimibe significantly improved lipid profiles. Visceral fat was decreased 7·2%, from 161·3 ± 58·6 cm(2) to 148·4 ± 52·7 cm(2) (P < 0·05), and adiponectin was increased 7·7%, from 3·61 ± 3·10 μg/mL to 3·86 ± 3·62 μg/mL (P < 0·05), after ezetimibe therapy; these beneficial effects were not observed in the control group. The increase in the adiponectin level was correlated with the reduction in visceral fat after ezetimibe treatment. Furthermore, ezetimibe reduced fasting insulin levels (P < 0·05) and improved the homoeostasis model assessment of insulin resistance (HOMA-IR) (P < 0·05).

CONCLUSIONS

Ezetimibe reduces visceral fat with beneficial effects on adiponectin and insulin resistance in patients with metabolic syndrome, suggesting a new therapeutic approach in such patients.

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.

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

AIM

Ezetimibe selectively blocks intestinal cholesterol absorption by inhibiting Niemann-Pick C1-like 1 (NPC1L1) and reducing LDL cholesterol (LDL-C). In animals, ezetimibe reversed diet-induced obesity, liver steatosis, and insulin resistance. In humans, its potential effects on liver steatosis and insulin resistance have been suggested. We investigated the effects of ezetimibe on postprandial hyperlipidaemia and hyperglycaemia in obese subjects with dyslipidaemia in a double-blind randomized crossover trial.

METHODS

Twenty obese men with hypertriglyceridaemia were assigned randomly to an ezetimibe- or a placebo-precedence-treated group. Subjects in the ezetimibe group were treated with ezetimibe (10 mg/day) for the first 4 weeks, followed by a 4-week interval and then treated with placebo for another 4 weeks. The placebo group received these treatments in reverse order. Subjects were requested to fast for at least 12 hours and then received a standard meal. Blood samples were collected at 0, 30, 60, 120, 240, 360 and 480 minutes after the meal on Days 0, 28, 56 and 84 and were used to measure the lipid and glucose metabolism markers.

RESULTS

Ezetimibe significantly decreased the postprandial serum triglyceride excursion (p=0.01) and fasting serum LDL-C, remnant-like particles(RLP) and ApoB48 levels (p<0.05). Postprandial glucose excursion, serum insulin levels, serum glucose-dependent insulinotropic polypeptide (GIP) and active glucagon-like peptide-1 (GLP-1) were not significantly affected by ezetimibe treatment.

CONCLUSION

Ezetimibe restored the postprandial dysregulation of lipid but did not affect glucose metabolism in a double-blind randomized crossover trial.

Non-alcoholic fatty liver disease and cardiovascular risk: metabolic aspects and novel treatments

Non-alcoholic fatty liver disease (NAFLD) is usually a silent disease that occurs in a very high proportion of people with features of the metabolic syndrome, including overweight, insulin resistance and type 2 diabetes. Because obesity and type 2 diabetes are now extremely common in Westernised societies, it is likely that the prevalence of NAFLD increases markedly in the future. Although previously it was thought that NAFLD was harmless, it is now recognised that NAFLD can be a progressive liver condition that increases risk of cirrhosis, end-stage liver disease and hepatocellular carcinoma. Additionally, liver fat accumulation causes insulin resistance and increases risk of type 2 diabetes. Increasing evidence now shows NAFLD is a risk factor for cardiovascular disease (CVD). The purpose of this review is to briefly discuss the pathogenesis of NAFLD, to describe the relationship between NAFLD and CVD and the mechanisms linking both conditions and to discuss some of the treatment options (including lifestyle, nutrition and drugs) that may influence both NAFLD and risk of CVD.

Comparison of the effects of simvastatin vs. rosuvastatin vs. simvastatin/ezetimibe on parameters of insulin resistance

BACKGROUND

Statin treatment may be associated with adverse effects on glucose metabolism. Whether this is a class effect is not known. In contrast, ezetimibe monotherapy may beneficially affect insulin sensitivity.

OBJECTIVE

The aim of this study was to compare the effects of three different regimens of equivalent low-density lipoprotein cholesterol (LDL-C) lowering capacity on glucose metabolism.

METHODS

A total of 153 patients (56 men), who had not achieved the LDL-C goal recommended by the National Cholesterol Education Program Adult Treatment Panel III (NCEP-ATP III) despite a 3-month dietary and lifestyle intervention, were randomly allocated to receive open-label simvastatin 40 mg or rosuvastatin 10 mg or simvastatin/ezetimibe 10/10 mg for 12 weeks. The primary end point was changes in homeostasis model assessment of insulin resistance (HOMA-IR). Secondary endpoints consisted of changes in fasting insulin levels, fasting plasma glucose (FPG), glycosylated haemoglobin (HbA(1c) ), the HOMA of β-cell function (HOMA-B) (a marker of basal insulin secretion by pancreatic β-cells), LDL-C and high sensitivity C reactive protein (hsCRP).

RESULTS

  At week 12, all three treatment regimens were associated with significant increases in HOMA-IR and fasting insulin levels (p < 0.05 compared with baseline). No significant difference was observed between groups. No change in FPG, HbA(1c) and HOMA-B levels compared with baseline were noted in any of the three treatment groups. Changes in serum lipids and hsCRP were similar across groups.

CONCLUSION

To the extent that simvastatin 40 mg, rosuvastatin 10 mg and simvastatin/ezetimibe 10/10 mg are associated with adverse effects on insulin resistance, they appear to be of the same magnitude.

Cholesterol-absorber status modifies the LDL cholesterol-lowering effect of a Mediterranean-type diet in adults with moderate cardiovascular risk factors

LDL-cholesterol (LDL-C) reduction may be achieved by various types of prudent diets, but their effects on surrogate markers of cholesterol absorption and synthesis have not been well studied in humans. We aimed to assess whether the extent of cholesterol absorption or synthesis, and cholesterol concentrations, are modified in adults when they shift from a Western-type diet (WD) to a combined low-fat, low-cholesterol/Mediterranean-type diet (LFCMD). Cholestanol and sitosterol, as well as desmosterol and lathosterol, surrogate markers of cholesterol absorption or synthesis, respectively, were quantified in the serum of 125 fasting, middle-aged participants at moderate cardiovascular risk. They habitually consumed a WD and then consumed a LFCMD during the 3-mo intervention. The group was stratified by serum cholestanol concentration and classified as high, intermediate, or low absorbers of cholesterol. When they consumed the WD, participants had comparable total and LDL-C concentrations, independent of absorber group and sex. After 3 mo of consuming the LFCMD, absorption and synthesis did not change or changed only slightly. The cholestanol concentration increased in low absorbers by 18% (P < 0.02) and decreased in high absorbers by 14% (P < 0.001), but these variations did not change the high- or low-absorber status. In male and female low absorbers, plasma total (-7%) and LDL-C (-9%) concentrations decreased after the 3-mo intervention and changes were 2.3- and 2.4-fold greater, respectively, than in high absorbers, independent of sex. Cholesterol synthesis/absorption status was not markedly altered by diet, but the decrease in plasma LDL-C due to the Mediterranean-type diet occurred only in low absorbers of cholesterol. This should be considered during further dietary interventions.