Determinants for Achieving the LDL-C Target of Lipid Control for Secondary Prevention of Cardiovascular Events in Taiwan

Background

Epidemiological and clinical studies have clearly established the link between low-density lipoprotein cholesterol (LDL-C) and atherosclerosis-related cardiovascular consequences. Although it has been a common practice for physicians to prescribe lipid-lowering therapy for patients with dyslipidemia, the achievement rate is still not satisfied in Taiwan. Therefore, the determinants for achieving the LDL-C target needed to be clarified for better healthcare of the patients with dyslipidemia.

Method

This registry-type prospective observational study enrolled the patients with cardiovascular diseases (coronary artery disease (CAD) and cerebrovascular disease (CVD)) from 18 medical centers across Taiwan, and clinically followed them for five years. At every clinical visit, vital signs, clinical endpoints, adverse events, concurrent medications and laboratory specimens were obtained as thoroughly as possible. The lipid profile (total cholesterol, high-density lipoprotein cholesterol, LDL-C, triglyceride), liver enzymes, and creatinine phosphokinase were evaluated at baseline, and every year thereafter. The cross sectional observational data was analyzed for this report.

Result

Among the 3,486 registered patients, 54% had their LDL-C < 100 mg/dL. By univariate analysis, the patients achieving the LDL-C target were associated with older age, more male sex, taller height, lower blood pressure, more under lipid-lowering therapy, more smoking cessation, more history of CAD, DM, physical activity, but less history of CVD. The multivariate analysis showed statin therapy was the most significant independent determinant for achieving the treatment target, followed by age, history of CAD, diabetes, blood pressure, and sex. However, most patients were on regimens of very-low to low equipotent doses of statins.

Conclusion

Although the lipid treatment guideline adherence is improving in recent years, only 54% of the patients with cardiovascular diseases have achieved their LDL-C target in Taiwan, and the most significant determinant for this was statin therapy.     

Advances in Lipid Testing and Management in Patients with Diabetes Mellitus

ObjectiveTo review the pathophysiologic basis for the classic phenotype associated with diabetic dyslipidemia, discuss recent advances in lipid and lipoprotein testing for risk assessment and lipid therapy monitoring, and summarize a systematic approach to the clinical management of diabetic dyslipidemia.MethodsWe review the pertinent literature, including treatment guidelines and results of major clinical trials, and discuss the effectiveness of various pharmacologic interventions for management of lipid levels in patients with diabetes.ResultsThe incidence and prevalence of type 2 diabetes mellitus continue to escalate globally at alarming rates. Diabetes predisposes to multiple microvascular and macrovascular complications, including cardiovascular disease, the number 1 cause of mortality in the United States. The third report of the National Cholesterol Education Program Adult Treatment Panel in 2001 identified diabetes as a coronary heart disease (CHD) risk equivalent, in light of the evidence that CHD risk in persons with diabetes is similar to that of nondiabetic persons with established CHD. Diabetic dyslipidemia is characterized by a constellation of lipid derangements—hypertriglyceridemia, a low concentration of high-density lipoprotein cholesterol (HDL-C), and a high concentration of small, dense low-density lipoprotein (LDL) particles—that accelerate the progression of atherosclerotic disease and the development of atherothrombotic events.ConclusionStatin trials have demonstrated significant reductions in morbidity and mortality from cardiovascular diseases, including in patients with diabetes. Nevertheless, many patients who achieve their LDL cholesterol (LDL-C) goal still have residual CHD risk. Diabetic dyslipidemia contributes to this residual risk because of the increased concentration of atherogenic apolipoprotein B-containing lipoproteins that can persist despite normalized LDL-C levels and low HDL-C levels. Recent clinical trials emphasize the importance of intensive lipid lowering to achieve recommended goals for LDL-C, non-HDL-C, and apolipoprotein B. (Endocr Pract. 2009;15:641-652)     

Lipodystrophic gene Agpat2 deficiency aggravates hyperlipidemia and atherosclerosis in Ldlr−/− mice

AimsDysfunction of adipose tissue increases the risk of cardiovascular disease. It was well established that obesity aggravates atherosclerosis, but the effect of adipose tissue loss on atherosclerosis has been less studied. AGPAT2 is the first causative gene of congenital generalized lipodystrophy (CGL), but the role of AGPAT2 on atherosclerosis has not been reported. Hypertriglyceridemia is one of the clinical manifestations of CGL patients, but it is usually absent in CGL mouse model on a normal diet. This study will investigate the effect of Agpat2 on hyperlipidemia and atherosclerosis.Methods and resultsIn this study, Agpat2 knockout (Agpat2^−/−) mice were generated using CRISPR/Cas system, which showed severe loss of adipose tissue and fatty liver, consistent with previous reports. Agpat2^−/− mice were then crossed with hypercholesterolemic and atherosclerotic prone LDL receptor knockout (Ldlr^−/−) mice to obtain double knockout mouse model (Agpat2^−/−Ldlr^−/−). Plasma lipid profile, insulin resistance, fatty liver, and atherosclerotic lesions were observed after 12 weeks of the atherogenic high-fat diet (HFD) feeding. We found that compared with Ldlr^−/− mice, Agpat2^−/−Ldlr^−/− mice showed significantly higher plasma total cholesterol and triglycerides after HFD feeding. Agpat2^−/−Ldlr^−/− mice also developed hyperglycemia and hyperinsulinemia, with increased pancreatic islet area. The liver weight of Agpat2^−/−Ldlr^−/− mice was about 4 times higher than that of Ldlr^−/− mice. The liver lipid deposition was severe and Sirius red staining showed liver fibrosis. In addition, in Agpat2^−/−Ldlr^−/− mice, the area of atherosclerotic lesions in aortic arch and aortic root was significantly increased.ConclusionsOur results show that Agpat2 deficiency led to more severe hyperlipidemia, liver fibrosis and aggravation of atherosclerosis in Ldlr^−/− mice. This study provided additional insights into the role of adipose tissue in hyperlipidemia and atherosclerosis.     

The role of hepatic Surf4 in lipoprotein metabolism and the development of atherosclerosis in apoE−/− mice

Elevated plasma levels of low-density lipoprotein-C (LDL-C) increase the risk of atherosclerotic cardiovascular disease. Circulating LDL is derived from very low-density lipoprotein (VLDL) metabolism and cleared by LDL receptor (LDLR). We have previously demonstrated that cargo receptor Surfeit 4 (Surf4) mediates VLDL secretion. Inhibition of hepatic Surf4 impairs VLDL secretion, significantly reduces plasma LDL-C levels, and markedly mitigates the development of atherosclerosis in LDLR knockout (Ldlr^?/?) mice. Here, we investigated the role of Surf4 in lipoprotein metabolism and the development of atherosclerosis in another commonly used mouse model of atherosclerosis, apolipoprotein E knockout (apoE^?/?) mice. Adeno-associated viral shRNA was used to silence Surf4 expression mainly in the liver of apoE^?/? mice. In apoE^?/? mice fed a regular chow diet, knockdown of Surf4 expression significantly reduced triglyceride secretion and plasma levels of non-HDL cholesterol and triglycerides without causing hepatic lipid accumulation or liver damage. When Surf4 was knocked down in apoE^?/? mice fed the Western-type diet, we observed a significant reduction in plasma levels of non-HDL cholesterol, but not triglycerides. Knockdown of Surf4 did not increase hepatic cholesterol and triglyceride levels or cause liver damage, but significantly diminished atherosclerosis lesions. Therefore, our findings indicate the potential of hepatic Surf4 inhibition as a novel therapeutic strategy to reduce the risk of atherosclerotic cardiovascular disease.     

Aggressive lipid management for cardiovascular prevention: evidence from clinical trials

Epidemiologic evidence shows that elevated serum cholesterol, specifically low-density lipoprotein cholesterol (LDL-C), increases the risk of coronary heart disease (CHD). Moreover, large-scale intervention trials demonstrate that treatment with HMG-CoA reductase inhibitors (statins), the most effective drug class for lowering LDL-C, significantly reduces the risk of CHD events. Unfortunately, only a moderate percentage of hypercholesterolemic patients are achieving LDL-C targets specified by the National Cholesterol Education Program (NCEP), in part because clinicians are not effectively titrating medications as needed to achieve LDL-C goals. Recent evidence suggests that more aggressive LDL-C lowering may provide greater clinical benefit, even in individuals with moderately elevated serum cholesterol levels. Furthermore, recent studies suggest that statins have cardioprotective effects in many high-risk individuals, including those with baseline LDL-C <100 mg/dl. High-density lipoprotein cholesterol (HDL-C) was recognized by the NCEP-Adult Treatment Panel II (ATP II) as a negative risk factor for CHD. The NCEP-ATP III guidelines have also reaffirmed the importance of HDL-C by increasing the low HDL-C designation from <35 to <40 mg/dl as a major risk factor for CHD. Similarly, triglyceride control will play a larger role in dyslipidemia management. As more clinicians effectively treat adverse lipid and lipoprotein cardiovascular risk factors, patients will likely benefit from reductions in cardiovascular events.     

Identification of the active site residues in ATP‐citrate lyase's carboxy‐terminal portion

ATP‐citrate lyase (ACLY) catalyzes production of acetyl‐CoA and oxaloacetate from CoA and citrate using ATP. In humans, this cytoplasmic enzyme connects energy metabolism from carbohydrates to the production of lipids. In certain bacteria, ACLY is used to fix carbon in the reductive tricarboxylic acid cycle. The carboxy(C)‐terminal portion of ACLY shows sequence similarity to citrate synthase of the tricarboxylic acid cycle. To investigate the roles of residues of ACLY equivalent to active site residues of citrate synthase, these residues in ACLY from Chlorobium limicola were mutated, and the proteins were investigated using kinetics assays and biophysical techniques. To obtain the crystal structure of the C‐terminal portion of ACLY, full‐length C. limicola ACLY was cleaved, first non‐specifically with chymotrypsin and subsequently with Tobacco Etch Virus protease. Crystals of the C‐terminal portion diffracted to high resolution, providing structures that show the positions of active site residues and how ACLY tetramerizes.     

Cholesteryl Ester Transfer Protein (CETP) Deficiency and CETP Inhibitors

Epidemiologic studies have shown that low-density lipoprotein cholesterol (LDL-C) is a strong risk factor, whilst high-density lipoprotein cholesterol (HDL-C) reduces the risk of coronary heart disease (CHD). Therefore, strategies to manage dyslipidemia in an effort to prevent or treat CHD have primarily attempted at decreasing LDL-C and raising HDL-C levels. Cholesteryl ester transfer protein (CETP) mediates the exchange of cholesteryl ester for triglycerides between HDL and VLDL and LDL. We have published the first report indicating that a group of Japanese patients who were lacking CETP had extremely high HDL-C levels, low LDL-C levels and a low incidence of CHD. Animal studies, as well as clinical and epidemiologic evidences, have suggested that inhibition of CETP provides an effective strategy to raise HDL-C and reduce LDL-C levels. Four CETP inhibitors have substantially increased HDL-C levels in dyslipidemic patients. This review will discuss the current status and future prospects of CETP inhibitors in the treatment of CHD. At present anacetrapib by Merck and evacetrapib by Eli Lilly are under development. By 100mg of anacetrapib HDL-C increased by 138%, and LDL-C decreased by 40%. Evacetrapib 500 mg also showed dramatic 132% increase of HDL-C, while LDL-C decreased by 40%. If larger, long-term, randomized, clinical end point trials could corroborate other findings in reducing atherosclerosis, CETP inhibitors could have a significant impact in the management of dyslipidemic CHD patients. Inhibition of CETP synthesis by antisense oligonucleotide or small molecules will produce more similar conditions to human CETP deficiency and may be effective in reducing atherosclerosis and cardiovascular events. We are expecting the final data of prospective clinical trials by CETP inhibitors in 2015.     

microRNA-30c reduces plasma cholesterol in homozygous familial hypercholesterolemic and type 2 diabetic mouse models

High plasma cholesterol levels are found in several metabolic disorders and their reductions are advocated to reduce the risk of atherosclerosis. A way to lower plasma lipids is to curtail lipoprotein production; however, this is associated with steatosis. We previously showed that microRNA (miR)-30c lowers diet-induced hypercholesterolemia and atherosclerosis in C57BL/6J and Apoe^−/− mice. Here, we tested the effect of miR-30c on plasma lipids, transaminases, and hepatic lipids in different mouse models. Hepatic delivery of miR-30c to chow-fed leptin-deficient (ob/ob) and leptin receptor-deficient (db/db) hypercholesterolemic and hyperglycemic mice reduced cholesterol in total plasma and VLDL/LDL by ∼28% and ∼25%, respectively, without affecting triglyceride and glucose levels. And these mice had lower plasma transaminases and creatine kinase activities than controls. Moreover, miR-30c significantly lowered plasma cholesterol and atherosclerosis in Western diet-fed Ldlr^−/− mice with no effect on plasma triglyceride, glucose, and transaminases. In these studies, hepatic lipids were similar in control and miR-30c-injected mice. Mechanistic studies showed that miR-30c reduced hepatic microsomal triglyceride transfer protein activity and lipid synthesis. Thus miR-30c reduced plasma cholesterol in several diet-induced and diabetic hypercholesterolemic mice. We speculate that miR-30c may be beneficial in lowering plasma cholesterol in different metabolic disorders independent of the origin of hypercholesterolemia.     

Modulation of hepatic lipidome by rhodioloside in high-fat diet fed apolipoprotein E knockout mice

BackgroundRhodioloside is a glucoside of tyrosol isolated from Rhodiola rosea. However, its regulating effect on hepatic dyslipidemia of atherogenic mice has rarely been studied.PurposeThe specific aims of current study included to clarify lipidomic perturbation in liver tissues of apolipoprotein E deficient (apoE^−/−) mice fed with high-fat diet, and to examine the effects of rhodioloside against atherosclerosis and dyslipidemia.Study DesignThe comparisons of hepatic lipidome were executed between wide type (WT) mice fed with normal diet (NDC) and apoE^−/− mice fed with high-fat diet (Model), WT mice fed with high-fat diet (HFDC) versus the model mice, as well as the model mice versus rhodioloside-treated atherosclerotic mice.MethodsUltra high performance liquid chromatography coupled with a Q exactive hybrid quadrupole-orbitrap mass spectrometry (UPLC-MS/MS) was employed to provide an unbiased and simultaneous measurement of individual lipid species in liver tissues.ResultsMultivariate statistical analysis derived from LC-MS spectra revealed that high-fat diet and apoE deficiency caused a series of disturbances on glyerolipid metabolism, glycerophospholipid metabolism and sphingolipid metabolism. Rhodioloside administration showed atheroprotective effects on the apoE^−/− mice with regulating the levels of 1 phosphatidylcholine, 2 phosphatidylserines, 5 alkyldiacylglycerols and 3 alkenyldiacylglycerols back to normal. In particular, PC (4:0/15:0) was positively associated with high-density lipoprotein cholesterol in blood, both of which could be ameliorated by rhodioloside.ConclusionOur results identified the abnormal hepatic lipids in atherosclerosis progression that could efficiently improved by rhodioloside. These lipids contributed to biological understanding of atherogenic dyslipidemia in liver and could also served as sensitive indicators for drug target screening.     

Apolipoprotein E receptor-2 deficiency enhances macrophage susceptibility to lipid accumulation and cell death to augment atherosclerotic plaque progression and necrosis

Genome-wide association studies have linked LRP8 polymorphisms to premature coronary artery disease and myocardial infarction in humans. However, the mechanisms by which dysfunctions of apolipoprotein E receptor-2 (apoER2), the protein encoded by LRP8 gene, influence atherosclerosis have not been elucidated completely. The current study focused on the role of apoER2 in macrophages, a cell type that plays an important role in atherosclerosis. Results showed that apoER2-deficient mouse macrophages accumulated more lipids and were more susceptible to oxidized LDL (oxLDL)-induced death compared to control cells. Consistent with these findings, apoER2 deficient macrophages also displayed defective serum-induced Akt activation and higher levels of the pro-apoptotic protein phosphorylated p53. Furthermore, the expression and activation of peroxisome proliferator-activated receptor γ (PPARγ) were increased in apoER2-deficient macrophages. Deficiency of apoER2 in hypercholesterolemic LDL receptor-null mice (Lrp8^−/−Ldlr^−/− mice) also resulted in accelerated atherosclerosis with more complex lesions and extensive lesion necrosis compared to Lrp8^+/+Ldlr^−/− mice. The atherosclerotic plaques of Lrp8^−/−Ldlr^−/− mice displayed significantly higher levels of p53-positive macrophages, indicating that the apoER2-deficient macrophages contribute to the accelerated atherosclerotic lesion necrosis observed in these animals. Taken together, this study indicates that apoER2 in macrophages limits PPARγ expression and protects against oxLDL-induced cell death. Thus, abnormal apoER2 functions in macrophages may at least in part contribute to the premature coronary artery disease and myocardial infarction in humans with LRP8 polymorphisms. Moreover, the elevated PPARγ expression in apoER2-deficient macrophages suggests that LRP8 polymorphism may be a genetic modifier of cardiovascular risk with PPARγ therapy.     

Acacetin exerts antioxidant potential against atherosclerosis through Nrf2 pathway in apoE−/− Mice

Oxidative stress has a considerable influence on endothelial cell dysfunction and atherosclerosis. Acacetin, an anti-inflammatory and antiarrhythmic, is frequently used in the treatment of myocarditis, albeit its role in managing atherosclerosis is currently unclear. Thus, we evaluated the regulatory effects of acacetin in maintaining endothelial cell function and further investigated whether the flavonoid could attenuate atherosclerosis in apolipoprotein E deficiency (apoE^−/−) mice. Different concentrations of acacetin were tested on EA.hy926 cells, either induced or non-induced by human oxidized low-density lipoprotein (oxLDL), to clarify its influence on cell viability, cellular reactive oxidative stress (ROS) level, apoptotic ratios and other regulatory effects. In vivo, apoE^−/− mice were fed either a Western diet or a chow diet. Acacetin pro-drug (15 mg/kg) was injected subcutaneously two times a day for 12 weeks. The effects of acacetin on the atherosclerotic process, plasma inflammatory factors and lipid metabolism were also investigated. Acacetin significantly increased EA.hy926 cell viability by reducing the ratios of apoptotic and necrotic cells at 3 μmol/L. Moreover, 3 μmol/L acacetin clearly decreased ROS levels and enhanced reductase protein expression through MsrA and Nrf2 pathway through phosphorylation of Nrf2 and degradation of Keap1. In vivo, acacetin treatment remarkably attenuated atherosclerosis by increasing reductase levels in circulation and aortic roots, decreasing plasma inflammatory factor levels as well as accelerating lipid metabolism in Western diet-fed apoE^−/− mice. Our findings demonstrate the anti-oxidative and anti-atherosclerotic effects of acacetin, in turn suggesting its potential therapeutic value in atherosclerotic-related cardiovascular diseases (CVD).     

Cow's milk polar lipids reduce atherogenic lipoprotein cholesterol,modulate gut microbiota and attenuate atherosclerosis development in LDL-receptor knockout mice fed a Western-type diet

Milk sphingomyelin (SM), a polar lipid (PL) component of milk fat globule membranes, is protective against dyslipidemia. However, it is unclear whether ingestion of milk PLs protect against atherosclerosis. To determine this, male LDLr^−/− mice (age 6 weeks) were fed ad libitum either a high-fat, added-cholesterol diet (CTL; 45% kcal from fat, 0.2% cholesterol by weight; n=15) or the same diet supplemented with 1% milk PL (1% MPL; n=15) or 2% milk PL (2% MPL; n=15) added by weight from butter serum. After 14 weeks on diets, mice fed 2% MPL had significantly lower serum cholesterol (−51%) compared to CTL (P<.01), with dose-dependent effects in lowering VLDL- and LDL-cholesterol. Mice fed 2% MPL displayed lower inflammatory markers in the serum, liver, adipose and aorta. Notably, milk PLs reduced atherosclerosis development in both the thoracic aorta and the aortic root, with 2% MPL-fed mice having significantly lower neutral lipid plaque size by 59% (P<.01) and 71% (P<.02) compared to CTL, respectively. Additionally, the 2% MPL-fed mice had greater relative abundance of Bacteroidetes, Actinobacteria and Bifidobacterium, and lower Firmicutes in cecal feces compared to CTL. Milk PL feeding resulted in significantly different microbial communities as demonstrated by altered beta diversity indices. In summary, 2% MPL strongly reduced atherogenic lipoprotein cholesterol, modulated gut microbiota, lowered inflammation and attenuated atherosclerosis development. Thus, milk PL content may be important to consider when choosing dairy products as foods for cardiovascular disease prevention.     

Results of the Dyslipidemia International Study (DYSIS)-Middle East: Clinical Perspective on the Prevalence and Characteristics of Lipid Abnormalities in the Setting of Chronic Statin Treatment

Background

Therapeutic intervention with low-density lipoprotein cholesterol-lowering agents known as statins has been demonstrated to reduce cardiovascular risk. However, many patients on statin treatment have persistent dyslipidemia and remain at a high risk of cardiovascular disease. Therefore, the objective of this study was to assess the frequency of lipid abnormalities in patients receiving chronic statin treatment.

Methods

As part of an international, cross-sectional, observational study, DYSIS-Middle East enrolled 2,182 patients in the United Arab Emirates (UAE), Saudi Arabia, Lebanon and Jordan. All patients were over 45 years of age and had been on statin treatment for at least three months. Data on demographics, lipid parameters and cardiovascular risk profile were recorded. Cardiovascular risk was defined according the guidelines of the European Society of Cardiology.

Results

The majority of patients (82.6%) were classified as being at very high risk of cardiovascular events, and 61.8% of all patients did not attain LDL-C target levels. Low high-density lipoprotein cholesterol levels and elevated triglyceride levels were noted in 55.5% and 48.5% of patients, respectively. Multivariate logistical regression modeling indicated that factors independently associated with LDL-C levels not being at goal were lifestyle choices, diabetes mellitus, ischemic heart disease, and blood pressure ≥ 140/90 mmHg.

Conclusions

Almost two-thirds of statin-treated patients in the United Arab Emirates, Saudi Arabia, Lebanon and Jordan had inadequately controlled lipid levels. More comprehensive surveillance, awareness and treatment regimens, as well as modification of lifestyle choices, is necessary to halt the rise in cardiovascular disease-related mortality.     

Procollagen C-endopeptidase Enhancer Protein 2 (PCPE2) Reduces Atherosclerosis in Mice by Enhancing Scavenger Receptor Class B1 (SR-BI)-mediated High-density Lipoprotein (HDL)-Cholesteryl Ester Uptake

Studies in human populations have shown a significant correlation between procollagen C-endopeptidase enhancer protein 2 (PCPE2) single nucleotide polymorphisms and plasma HDL cholesterol concentrations. PCPE2, a 52-kDa glycoprotein located in the extracellular matrix, enhances the cleavage of C-terminal procollagen by bone morphogenetic protein 1 (BMP1). Our studies here focused on investigating the basis for the elevated concentration of enlarged plasma HDL in PCPE2-deficient mice to determine whether they protected against diet-induced atherosclerosis. PCPE2-deficient mice were crossed with LDL receptor-deficient mice to obtain LDLr^−/−, PCPE2^−/− mice, which had elevated HDL levels compared with LDLr^−/− mice with similar LDL concentrations. We found that LDLr^−/−, PCPE2^−/− mice had significantly more neutral lipid and CD68+ infiltration in the aortic root than LDLr^−/− mice. Surprisingly, in light of their elevated HDL levels, the extent of aortic lipid deposition in LDLr^−/−, PCPE2^−/− mice was similar to that reported for LDLr^−/−, apoA-I^−/− mice, which lack any apoA-I/HDL. Furthermore, LDLr^−/−, PCPE2^−/− mice had reduced HDL apoA-I fractional clearance and macrophage to fecal reverse cholesterol transport rates compared with LDLr^−/− mice, despite a 2-fold increase in liver SR-BI expression. PCPE2 was shown to enhance SR-BI function by increasing the rate of HDL-associated cholesteryl ester uptake, possibly by optimizing SR-BI localization and/or conformation. We conclude that PCPE2 is atheroprotective and an important component of the reverse cholesterol transport HDL system.     

Perilipin 5 deficiency promotes atherosclerosis progression through accelerating inflammation,apoptosis, and oxidative stress

Excessive plasma triglyceride (TG) and cholesterol levels promote the progression of several prevalent cardiovascular risk factors, including atherosclerosis, which is a leading death cause. Perilipin 5 (Plin5), an important perilipin protein, is abundant in tissues with very active lipid catabolism and is involved in the regulation of oxidative stress. Although inflammation and oxidative stress play a critical role in atherosclerosis development, the underlying mechanisms are complex and not completely understood. In the present study, we demonstrated the role of Plin5 in high-fat-diet-induced atherosclerosis in apolipoprotein E null (ApoE^−/−) mice. Our results suggested that Plin5 expressions increased in the artery tissues of ApoE^−/− mice. ApoE/Plin5 double knockout (ApoE^−/−Plin5^−/−) exacerbated severer atherogenesis, accompanied with significantly disturbed plasma metabolic profiles, such as elevated TG, total cholesterol, and low-density lipoprotein cholesterol levels and reduced high-density lipoprotein cholesterol contents. ApoE^−/−Plin5^−/− exhibited a higher number of inflammatory monocytes and neutrophils, as well as overexpression of cytokines and chemokines linked with an inflammatory response. Consistently, the IκBα/nuclear factor kappa B pathway was strongly activated in ApoE^−/−Plin5^−/−. Notably, apoptosis was dramatically induced by ApoE^−/−Plin5^−/−, as evidenced by increased cleavage of Caspase-3 and Poly (ADP-ribose) polymerase-2. In addition, ApoE^−/−Plin5^−/− contributed to oxidative stress generation in the aortic tissues, which was linked with the activation of phosphatidylinositol 3-kinase/protein kinase B and mitogen-activated protein kinases pathways. In vitro, oxidized low-density lipoprotein (ox-LDL) increased Plin5 expression in RAW264.7 cells. Its knockdown enhanced inflammation, apoptosis, oxidative stress, and lipid accumulation, while promotion of Plin5 markedly reduced all the effects induced by ox-LDL in cells. These studies strongly supported that Plin5 could be a new regulator against atherosclerosis, providing new insights on therapeutic solutions.     

Beneficial effects of a novel IH636 grape seed proanthocyanidin extract and a niacin-bound chromium in a hamster atherosclerosis model

Atherosclerosis is a disease of the arteries in which fatty plaques develop on the inner arterial wall, which eventually obstructs blood flow. Identified risk factors for atherosclerosis include genetics, diet, lifestyle, smoking, circulating lipid and cholesterol levels, and molecular and circulating signals of chronic vascular inflammation. The link between flavonoids and atherosclerosis is based partly on the evidence that some flavonoids possess antioxidant properties and have been shown to be potent inhibitors of LDL oxidation in vitro. Hypercholesterolemia, a significant cardiovascular risk factor is prevalent in the American population. Grape seed proanthocyanidin extracts are known to exhibit a broad spectrum of chemopreventive and cardioprotective properties against oxidative stress. A recent study has shown that a combination of IH636 grape seed proanthocyanidin extract (GSPE) and a niacin-bound chromium (NBC) can decrease total cholesterol, LDL and oxidized LDL levels in hypercholesterolemic human subjects. In this study, we assessed the efficacy of GSPE supplementation in hamsters, singly and in combination with NBC, since these animals have a similar lipid profile to hypercholesterolemic humans when fed a hypercholesterolemic diet of 0.2% cholesterol and 10% coconut oil (HCD). After 10 weeks of feeding HCD, these animals developed foam cells, which is a biomarker of early stages of atherosclerosis. Atherosclerosis (% of aorta covered with foam cells) was reduced by approximately 50% and 63% following supplementation of these animals with 50 mg/kg and 100 mg/kg of GSPE, respectively, in conjunction with a HCD, while approximately 32% reduction was observed following supplementation of GSPE plus NBC. A minimum of 7–9 animals were used in each study group. GSPE alone and in combination with NBC exerted a pronounced effect on the cholesterol, and triglyceride levels, as well as oxidative lipid damage as demonstrated by the formation of thiobarbituric acid reactive substances (TBARS). This data demonstrates that GSPE and NBC may provide significant health benefits by dramatically ameliorating the incidence of atherosclerosis as demonstrated by reducing the formation of foam cells.     

Effect of Diets Containing Sucrose vs. D‐tagatose in Hypercholesterolemic Mice

Effects of functional sweeteners on the development of the metabolic syndrome and atherosclerosis are unknown. The objective was to compare the effect of dietary carbohydrate in the form of sucrose (SUCR) to D‐tagatose (TAG; an isomer of fructose currently used as a low‐calorie sweetener) on body weight, blood cholesterol concentrations, hyperglycemia, and atherosclerosis in low‐density lipoprotein receptor deficient (LDLr^−/−) mice. LDLr^−/− male and female mice were fed either standard murine diet or a diet enriched with TAG or SUCR as carbohydrate sources for 16 weeks. TAG and SUCR diets contained equivalent amounts (g/kg) of protein, fat, and carbohydrate. We measured food intake, body weight, adipocyte diameter, serum cholesterol and lipoprotein concentrations, and aortic atherosclerosis. Macrophage immunostaining and collagen content were examined in aortic root lesions. CONTROL and TAG‐fed mice exhibited similar energy intake, body weights and blood glucose and insulin concentrations, but SUCR‐fed mice exhibited increased energy intake and became obese and hyperglycemic. Adipocyte diameter increased in female SUCR‐fed mice compared to TAG and CONTROL. Male and female SUCR‐fed mice had increased serum cholesterol and triglyceride concentrations compared to TAG and CONTROL. Atherosclerosis was increased in SUCR‐fed mice of both genders compared to TAG and CONTROL. Lesions from SUCR‐fed mice exhibited pronounced macrophage immunostaining and reductions in collagen content compared to TAG and CONTROL mice. These results demonstrate that in comparison to sucrose, equivalent substitution of TAG as dietary carbohydrate does not result in the same extent of obesity, hyperglycemia, hyperlipidemia, and atherosclerosis.     

Therapeutic effects of rosuvastatin in hypercholesterolemic prediabetic mice in the absence of low density lipoprotein receptor

Statins are effective drugs used to prevent and treat cardiovascular diseases but their effects in the absence of low density lipoprotein receptor (LDLR) and on the risk of diabetes are not yet well characterized. The aim of this study was to clarify systemic and pleiotropic effects of rosuvastatin on cardiovascular and diabetic phenotypes.IGF-II/LDLR^?/?ApoB^100/100 hypercholesterolemic prediabetic mice were used to test the effects of rosuvastatin on plasma glucose, insulin, lipids, atherosclerosis and liver steatosis. To get a more comprehensive view about changes in gene expression RNA-sequencing was done from the liver.Rosuvastatin significantly reduced plasma cholesterol in hypercholesterolemic mice in the absence of LDLR but had no effects on atherosclerosis at aortic sinus level or in coronary arteries. Rosuvastatin also significantly reduced liver steatosis without any harmful effects on glucose or insulin metabolism. RNA-sequencing showed relatively specific effects of rosuvastatin on genes involved in cholesterol metabolism together with a significant anti-inflammatory gene expression profile in the liver. In addition, significant changes were found in the expression of Perilipin 4 and 5 which are involved in lipid droplet formation in the liver. For the first time it could be shown that Tribbles proteins are affected by rosuvastatin treatment in the hyperlipidemic mice. Rosuvastatin had several positive effects on hypercholesterolemic mice showing early signs of diabetes, many of which are unrelated to cholesterol and lipoprotein metabolism. These results increase our understanding about the systemic and pleiotropic effects of rosuvastatin in the absence of LDLR expression.     

Hypercholesterolemia in young adult APOE−/− mice alters epidermal lipid composition and impairs barrier function

Long-term exposure to hypercholesterolemia induces the development of skin xanthoma's characterized by the accumulation of lipid-laden foam cells in humans and in mice. Early skin changes in response to hypercholesterolemia are however unknown. In this study, we investigated the skin lipid composition and associated barrier function in young adult low-density lipoprotein receptor knockout (LDLR^−/−) and apolipoprotein E knockout (APOE^−/−) mice, two commonly used hypercholesterolemic mouse models characterized by the accumulation of apolipoprotein B containing lipoproteins. No differences were observed on cholesterol content in the epidermis in LDLR^−/− mice nor in the more extremely hypercholesterolemic APOE^−/− mice. Interestingly, the free fatty acid profile in the APOE^−/− epidermis shifted towards shorter and unsaturated chains. Genes involved in the synthesis of cholesterol and fatty acids were downregulated in APOE^−/− skin suggesting a compensation for the higher influx of plasma lipids, most probably as cholesteryl esters. Importantly, in vivo transepidermal water loss and permeability studies with murine lipid model membranes revealed that the lipid composition of the APOE^−/− skin resulted in a reduced skin barrier function. In conclusion, severe hypercholesterolemia associated with increased apolipoprotein B containing lipoproteins affects the epidermal lipid composition and its protective barrier.