Differential Impact In Vivo of Pf4-ΔCre-Mediated and Gp1ba-ΔCre-Mediated Depletion of Cyclooxygenase-1 in Platelets in Mice.

BACKGROUND: Low-dose aspirin is widely used for the secondary prevention of cardiovascular disease. The beneficial effects of low-dose aspirin are attributable to its inhibition of platelet Cox (cyclooxygenase)-1-derived thromboxane A2. Until recently, the use of the Pf4 (platelet factor 4) Cre has been the only genetic approach to generating megakaryocyte/platelet ablation of Cox-1 in mice. However, Pf4-ΔCre displays ectopic expression outside the megakaryocyte/platelet lineage, especially during inflammation. The use of the Gp1ba (glycoprotein 1bα) Cre promises a more specific, targeted approach. METHODS: To evaluate the role of Cox-1 in platelets, we crossed Pf4-ΔCre or Gp1ba-ΔCre mice with Cox-1flox/flox mice to generate platelet Cox-1-/- mice on normolipidemic and hyperlipidemic (Ldlr-/-; low-density lipoprotein receptor) backgrounds. RESULTS: Ex vivo platelet aggregation induced by arachidonic acid or adenosine diphosphate in platelet-rich plasma was inhibited to a similar extent in Pf4-ΔCre Cox-1-/-/Ldlr-/- and Gp1ba-ΔCre Cox-1-/-/Ldlr-/- mice. In a mouse model of tail injury, Pf4-ΔCre-mediated and Gp1ba-ΔCre-mediated deletions of Cox-1 were similarly efficient in suppressing platelet prostanoid biosynthesis. Experimental thrombogenesis and attendant blood loss were similar in both models. However, the impact on atherogenesis was divergent, being accelerated in the Pf4-ΔCre mice while restrained in the Gp1ba-ΔCres. In the former, accelerated atherogenesis was associated with greater suppression of PGI2 biosynthesis, a reduction in the lipopolysaccharide-evoked capacity to produce PGE2 (prostaglandin E) and PGD2 (prostanglandin D), activation of the inflammasome, elevated plasma levels of IL-1ß (interleukin), reduced plasma levels of HDL-C (high-density lipoprotein receptor-cholesterol), and a reduction in the capacity for reverse cholesterol transport. By contrast, in the latter, plasma HDL-C and α-tocopherol were elevated, and MIP-1α (macrophage inflammatory protein-1α) and MCP-1 (monocyte chemoattractant protein 1) were reduced. CONCLUSIONS: Both approaches to Cox-1 deletion similarly restrain thrombogenesis, but a differential impact on Cox-1-dependent prostanoid formation by the vasculature may contribute to an inflammatory phenotype and accelerated atherogenesis in Pf4-ΔCre mice.

New Insight Into Metformin-Induced Cholesterol-Lowering Effect Crosstalk Between Glucose and Cholesterol Homeostasis via ChREBP (Carbohydrate-Responsive Element-Binding Protein)-Mediated PCSK9 (Proprotein Convertase Subtilisin/Kexin Type 9) Regulation.

[Figure: see text].

Kanglexin, a new anthraquinone compound, attenuates lipid accumulation by activating the AMPK/SREBP-2/PCSK9/LDLR signalling pathway.

Hyperlipidaemia is one of the major risk factors for atherosclerosis, coronary heart disease, stroke and diabetes. In the present study, we synthesized a new anthraquinone compound, 1,8-dihydroxy-3-succinic acid monoethyl ester-6-methylanthraquinone, and named it Kanglexin (KLX). The aim of this study was to evaluate whether KLX has a lipid-lowering effect and to explore the potential molecular mechanism. In this study, Sprague-Dawley rats were fed a high fat diet (HFD) for 5 weeks to establish a hyperlipidaemia model; then, the rats were orally administered KLX (20, 40, and 80 mg kg-1·d-1) or atorvastatin calcium (AT, 10 mg kg-1·d-1) once a day for 2 weeks. KLX had prominent effects on reducing blood lipids, hepatic lipid accumulation, body weight and the ratio of liver weight/body weight. Furthermore, KLXdramatically reduced the total cholesterol (TC) and triglyceride (TG) levels and lipid accumulation in a HepG2 cell model of dyslipidaemia induced by 1 mmol/L oleic acid (OA). KLX may decrease lipid levels by phosphorylating adenosine monophosphate-activated protein kinase (AMPK) and the downstream sterol regulatory element binding protein 2 (SREBP-2)/proprotein convertase subtilisin/kexin type 9 (PCSK9)/low-density lipoprotein receptor (LDLR) signalling pathway in the HFD rats and OA-treated HepG2 cells. The effects of KLX on the AMPK/SREBP-2/PCSK9/LDLR signalling pathway were abolished when AMPK was inhibited by compound C (a specific AMPK inhibitor) in HepG2 cells. In summary, KLX has an efficient lipid-lowering effect mediated by activation of the AMPK/SREBP-2/PCSK9/LDLR signalling pathway. Our findings may provide new insight into and evidence for the discovery of a new lipid-lowering drug for the prevention and treatment of hyperlipidaemia, fatty liver, and cardiovascular disease in the clinic.

Partial analytical validation of the VetScan cPL rapid test.

BACKGROUND: Serum canine pancreatic lipase immunoreactivity (cPLI) concentrations have become the standard laboratory test used to diagnose canine pancreatitis. Recently, a new point-of-care assay for cPLI, the VetScan cPL rapid test (VetScan cPL), has become available, but analytical validation data have not yet been published. OBJECTIVE: This study aimed to perform a partial analytical validation of the VetScan cPL. METHODS: Leftover serum samples from a diagnostic laboratory were used. Adherence to the manufacturer's guidelines, linearity, repeatability, and reproducibility were evaluated. Results of the VetScan cPL were correlated with the Spec cPL results. RESULTS: Observed-to-expected ratios for dilutional parallelism ranged from 77.4% to 162.9% (mean 119.3%). Intra-assay and inter-assay variabilities ranged from 16.9% to 36.7% (mean 25.1%) and from 14.1% to 51.2% (mean 31.8%), respectively. Adherence to the manufacturer's specification regarding results within ± 60 µg/L of the Spec cPL result was only achieved for 39% of the measurements. The VetScan cPL and Spec cPL correlation showed a Spearman's r of .758 for 29 data pairs. CONCLUSIONS: Under the conditions of this study, the VetScan cPL did not adhere to the manufacturer's specifications for most measurements. Also, the VetScan cPL showed suboptimal linearity and was not precise. In conclusion, the VetScan cPL failed basic analytical validation.

Development of Wheat Bran Oil Concentrates Rich in Bioactives with Antioxidant and Hypolipidemic Properties.

Wheat bran, an abundant byproduct of the milling industry, comprises fat-soluble bioactives and fibers. In the present study, two concentrates were prepared from wheat bran oil (WBO) using silicic acid coupled with acetone (WBA) and hexane (WBH). WBA extract had enhanced color and viscosity and was enriched with fat-soluble bioactives (sterols, oryzanol-like compounds, tocopherols, and carotenoids) as evidenced from NMR and other techniques. In in vitro studies, WBA exhibited significant free radical scavenging activity, limited DNA and LDL oxidation, and inhibiting HMG-CoA reductase and lipase activity better than WBH and WBO. Further, an in vivo study with WBA 2 or 3.5% containing high fat diet ameliorated malonaldehyde (MDA) level, lipid profile, and antioxidant enzyme (SOD, catalase, GPx, and GR) activities in liver. A possible reason for this effect is downregulation of HMG-CoA reductase expression with WBA. Thus, WBA has significant potential as an ingredient in health food formulations.

Paraoxonase-1 and myeloperoxidase correlate with vascular biomarkers in overweight patients with newly diagnosed untreated hyperlipidaemia.

BACKGROUND: In hyperlipidaemic state, increased levels of myeloperoxidase (MPO) and decreased paraoxonase-1 (PON1) activity have been reported; however, their relationships with other atherosclerotic biomarkers have not been completely clarified. PATIENTS AND METHODS: Serum concentrations of lipid and inflammatory parameters, MPO levels, and PON1 activities were investigated in 167 untreated hyperlipidaemic patients with and without vascular complications and in 32 healthy controls. Additionally, levels of CD40 ligand (sCD40L) and asymmetric dimethyl arginine (ADMA), soluble intercellular adhesion molecule-1 (sICAM-1), soluble vascular cell adhesion molecule-1, and oxidized LDL were determined. RESULTS: We found elevated C-reactive protein (CRP), ADMA, sCD40L, sICAM-1 concentrations, and higher MPO levels in patients with vascular complications compared to those without. The PON1 arylesterase activity correlated negatively with sCD40L, ADMA, and sICAM-1 levels, respectively. In contrast, MPO concentrations showed positive correlations with sCD40L, ADMA, and sICAM-1 levels, respectively. CONCLUSIONS: It can therefore be stated that PON1 activity and MPO level correlate strongly with the vascular biomarkers, highlighting the importance of the HDL-associated pro- and antioxidant enzymes in the development of endothelial dysfunction and atherogenesis.

Current smokers with hyperlipidemia lack elevated preß1-high-density lipoprotein concentrations.

BACKGROUND: Preß1-high-density lipoprotein (HDL) is an efficient acceptor of cell-derived free cholesterol, which is converted into lipid-rich HDL by lecithin-cholesterol acyltransferase. Previous studies have shown that preß1-HDL is significantly higher in individuals with hyperlipidemia. Preß1-HDL concentrations may be altered in smokers, who are at high risk for atherosclerosis. OBJECTIVE: The aim of the present study was to investigate the effect of smoking on preß1-HDL concentrations. METHODS: We measured the preß1-HDL concentration and lecithin-cholesterol acyltransferase-dependent conversion rate (CHTpreß1) in 74 men (39 nonsmokers and 35 smokers) using an immunoassay. RESULTS: The smoker and nonsmoker groups were further divided into normolipidemic and hyperlipidemic subjects. Among nonsmokers, the mean preß1-HDL concentration was 27% higher in hyperlipidemics than in normolipidemics (25.5 ± 6.7 vs 20.3 ± 4.6 mg/L apoAI, P < .01). In contrast, mean preß1-HDL concentrations did not differ between hyperlipidemic and normolipidemic smokers (19.9 ± 3.1 vs 22.4 ± 6.9 mg/L apoAI). We found a positive correlation between preß1-HDL concentration and CHTpreß1 in nonsmokers, but not in smokers. Smoking a single cigarette did not change preß1-HDL concentrations or CHTpreß1. Compared with nonsmokers, preß1-HDL concentrations were relatively low in hyperlipidemic smokers but not in normolipidemic smokers, and CHTpreß1 was not a significant determinant of preß1-HDL concentrations in smokers. CONCLUSION: Our findings suggest that smoking may be disadvantageous to individuals with hyperlipidemia because preß1-HDL metabolism is altered.

Preservation of vascular DDAH activity contributes to the protection of captopril against endothelial dysfunction in hyperlipidemic rabbits.

Endothelial dysfunction plays a pivotal role in the pathogenesis of atherosclerosis. Endogenous inhibitor of nitric oxide synthase (NOS) asymmetric dimethylarginine (ADMA) has been recognized as an independent risk factor of endothelial dysfunction and the biomarker of atherosclerosis. This study was to investigate whether endogenous ADMA and its metabolic enzyme dimethylarginine dimethylaminohydrolase (DDAH) were involved in mechanisms of captopril protection against endothelial dysfunction in high fat diet feeding rabbits. Half of model rabbits were treated with captopril (10mg/kg/d, i.g.) for 12w. Vascular morphology and serum lipid profiles were detected. Serum ADMA concentration were assayed by high performance liquid chromatography. Recombinant DDAH2 gene adenoviruses were ex vivo transferred to thoracic aortas of high fat diet feeding rabbits. Endothelium-dependent relaxation of aortas response to acetylcholine and DDAH activity were measured. Atherosclerosis was confirmed in high fat diet feeding rabbits by increased serum lipid profiles and morphologic changes of vascular wall. Serum ADMA levels were significantly increased in hyperlipidemic rabbits accompanied with impairment of endothelium-dependent relaxation and inhibition of DDAH activity in thoracic aortas. Captopril treatment not only decreased vascular intima thickening and serum ADMA concentration but also preserved vascular DDAH activity and endothelium-dependent relaxation in hyperlipidemic rabbits without influence on serum lipid profiles. Similar beneficial effects on endothelial function and DDAH activity could be achieved by DDAH2 gene transfection. These results indicated that captopril could protect against injuries of vascular morphology and endothelial function in hyperlipidemic rabbits, the mechanisms may be related to the preservation of DDAH activity and decrease of ADMA accumulation in vascular endothelium.

Association of the Common Catalase Gene Polymorphism rs1001179 With Glycated Hemoglobin and Plasma Lipids in Hyperlipidemic Patients.

Catalase represents perhaps the most effective antioxidant defense in the body under conditions of increased oxidative stress, and rs1001179 (CAT-262C >T) is its most extensively studied gene polymorphism. Using an established PCR-RFLP method for genotyping, we examined the association of rs1001179 with glycated hemoglobin (HbA1c) and plasma lipids using univariate analyses with age, sex, body mass index (BMI), smoking, and alcohol abuse as covariates, in a group of dyslipidemic patients from northern Greece. Our results suggest that the TT genotype is a risk factor for increased HbA1c and plasma triglycerides, and that this association is modulated by the BMI and/or age of the patients.

Physiological Study on Association between Nicotinamide N-Methyltransferase Gene Polymorphisms and Hyperlipidemia.

Nicotinamide N-methyltransferase (NNMT) catalyzes the methylation of nicotinamide. Our previous works indicate that NNMT is involved in the body mass index and energy metabolism, and recently the association between a SNP (rs694539) of NNMT and a variety of cardiovascular diseases was reported. At present, more than 200 NNMT single nucleotide polymorphisms (SNPs) have been identified in the databases of the human genome projects; however, the association between rs694539 variation and hyperlipidemia has not been reported yet, and whether there are any SNPs in NNMT significantly associated with hyperlipidemia is still unclear. In this paper, we selected 19 SNPs in NNMT as the tagSNPs using Haploview software (Haploview 4.2) first and then performed a case-control study to observe the association between these tagSNPs and hyperlipidemia and finally applied physiological approaches to explore the possible mechanisms through which the NNMT polymorphism induces hyperlipidemia. The results show that a SNP (rs1941404) in NNMT is significantly associated with hyperlipidemia, and the influence of rs1941404 variation on the resting energy expenditure may be the possible mechanism for rs1941404 variation to induce hyperlipidemia.

A study on the association between hyperlipidemia and hypothyroidism and the response to TKIs in metastatic renal cell carcinoma.

AIM: Vascular endothelial growth facto receptor-tyrosine kinase inhibitors (VEGFR-TKIs) are widely used for metastatic renal cell carcinoma (mRCC). The aim of this study was to investigate the association between the response to VEGFR-TKIs and hyperlipidemia and hypothyroidism. METHODS: Clinical data on 155 patients with mRCC treated with VEGFR-TKIs at the Cancer Hospital of Chinese Academy of Medical Sciences from 2006 to 2014 were retrospectively analyzed. All patients received first-line TKI therapy. Survival analysis was performed with a significance level of 0.05 using a Kaplan-Meier curve. The χ(2) test was used for the intergroup comparison. The Cox regression model was used for the analysis of multiple factors affecting survival. RESULTS: The median survival for the whole group (n = 155) was 36.2 months. A total of 57 patients (36.8 percent) developed hypothyroidism and 85 patients (54.9 percent) experienced hyperlipidemia. The response rate (RR) and median progression-free survival (mPFS) for patients with normal thyroid function were 32.7 percent and 9.1 months, respectively, 54.5 percent and 13.7 months with grade I hypothyroidism, 70.8 percent and 23.8 months with grade II hypothyroidism (P values of 0.001 and 0.017, respectively). The RR and mPFS for patients with normal blood lipids were 23.9 percent and 8.0 months, respectively, 54.0 percent and 12.9 months with grade I hyperlipidemia, 60.7 percent and 14.0 months with grade II hyperlipidemia, and 100.0 percent and 22.2 months with grade III hyperlipidemia. Significant differences in the RR and mPFS were seen between groups (the P values were 0.000 and 0.005, respectively). CONCLUSION: Hypothyroidism or hyperlipidemia may be effective predictive factors for response to treatment with VEGFR-TKIs in mRCC patients. Large-sample studies are warranted to further prove these results.

Pharmacological Inhibition of Monoacylglycerol O-Acyltransferase 2 Improves Hyperlipidemia, Obesity, and Diabetes by Change in Intestinal Fat Utilization.

Monoacylglycerol O-acyltransferase 2 (MGAT2) catalyzes the synthesis of diacylglycerol (DG), a triacylglycerol precursor and potential peripheral target for novel anti-obesity therapeutics. High-throughput screening identified lead compounds with MGAT2 inhibitory activity. Through structural modification, a potent, selective, and orally bioavailable MGAT2 inhibitor, compound A (compA), was discovered. CompA dose-dependently inhibited postprandial increases in plasma triglyceride (TG) levels. Metabolic flux analysis revealed that compA inhibited triglyceride/diacylglycerol resynthesis in the small intestine and increased free fatty acid and acyl-carnitine with shorter acyl chains than originally labelled fatty acid. CompA decreased high-fat diet (HFD) intake in C57BL/6J mice. MGAT2-null mice showed a similar phenotype as compA-treated mice and compA did not suppress a food intake in MGAT2 KO mice, indicating that the anorectic effects were dependent on MGAT2 inhibition. Chronic administration of compA significantly prevented body weight gain and fat accumulation in mice fed HFD. MGAT2 inhibition by CompA under severe diabetes ameliorated hyperglycemia and fatty liver in HFD-streptozotocin (STZ)-treated mice. Homeostatic model assessments (HOMA-IR) revealed that compA treatment significantly improved insulin sensitivity. The proximal half of the small intestine displayed weight gain following compA treatment. A similar phenomenon has been observed in Roux-en-Y gastric bypass-treated animals and some studies have reported that this intestinal remodeling is essential to the anti-diabetic effects of bariatric surgery. These results clearly demonstrated that MGAT2 inhibition improved dyslipidemia, obesity, and diabetes, suggesting that compA is an effective therapeutic for obesity-related metabolic disorders.

PPARδ activation induces hepatic long-chain acyl-CoA synthetase 4 expression in vivo and in vitro.

The arachidonic acid preferred long-chain acyl-CoA synthetase 4 (ACSL4) is a key enzyme for fatty acid metabolism in various metabolic tissues. In this study, we utilized hamsters fed a normal chow diet, a high-fat diet or a high cholesterol and high fat diet (HCHFD) as animal models to explore novel transcriptional regulatory mechanisms for ACSL4 expression under hyperlipidemic conditions. Through cloning hamster ACSL4 homolog and tissue profiling ACSL4 mRNA and protein expressions we observed a selective upregulation of ACSL4 in testis and liver of HCHFD fed animals. Examination of transcriptional activators of the ACSL family revealed an increased hepatic expression of PPARδ but not PPARα in HCHFD fed hamsters. To explore a role of PPARδ in dietary cholesterol-mediated upregulation of ACSL4, we administered a PPARδ specific agonist L165041 to normolipidemic and dyslipidemic hamsters. We observed significant increases of hepatic ACSL4 mRNA and protein levels in all L165041-treated hamsters as compared to control animals. The induction of ACSL4 expression by L165041 in liver tissue in vivo was recapitulated in human primary hepatocytes and hepatocytes isolated from hamster and mouse. Moreover, employing the approach of adenovirus-mediated gene knockdown, we showed that depletion of PPARδ in hamster hepatocytes specifically reduced ACSL4 expression. Finally, utilizing HepG2 as a model system, we demonstrate that PPARδ activation leads to increased ACSL4 promoter activity, mRNA and protein expression, and consequently higher arachidonoyl-CoA synthetase activity. Taken together, we have discovered a novel PPARδ-mediated regulatory mechanism for ACSL4 expression in liver tissue and cultured hepatic cells.

Early hyperlipidemia promotes endothelial activation via a caspase-1-sirtuin 1 pathway.

OBJECTIVE: The role of receptors for endogenous metabolic danger signals-associated molecular patterns has been characterized recently as bridging innate immune sensory systems for danger signals-associated molecular patterns to initiation of inflammation in bone marrow-derived cells, such as macrophages. However, it remains unknown whether endothelial cells (ECs), the cell type with the largest numbers and the first vessel cell type exposed to circulating danger signals-associated molecular patterns in the blood, can sense hyperlipidemia. This report determined whether caspase-1 plays a role in ECs in sensing hyperlipidemia and promoting EC activation. APPROACH AND RESULTS: Using biochemical, immunologic, pathological, and bone marrow transplantation methods together with the generation of new apoplipoprotein E (ApoE)(-/-)/caspase-1(-/-) double knockout mice, we made the following observations: (1) early hyperlipidemia induced caspase-1 activation in ApoE(-/-) mouse aorta; (2) caspase-1(-/-)/ApoE(-/-) mice attenuated early atherosclerosis; (3) caspase-1(-/-)/ApoE(-/-) mice had decreased aortic expression of proinflammatory cytokines and attenuated aortic monocyte recruitment; and (4) caspase-1(-/-)/ApoE(-/-) mice had decreased EC activation, including reduced adhesion molecule expression and cytokine secretion. Mechanistically, oxidized lipids activated caspase-1 and promoted pyroptosis in ECs by a reactive oxygen species mechanism. Caspase-1 inhibition resulted in accumulation of sirtuin 1 in the ApoE(-/-) aorta, and sirtuin 1 inhibited caspase-1 upregulated genes via activator protein-1 pathway. CONCLUSIONS: Our results demonstrate for the first time that early hyperlipidemia promotes EC activation before monocyte recruitment via a caspase-1-sirtuin 1-activator protein-1 pathway, which provides an important insight into the development of novel therapeutics for blocking caspase-1 activation as early intervention of metabolic cardiovascular diseases and inflammations.

Amino acid, mineral, and polyphenolic profiles of black vinegar, and its lipid lowering and antioxidant effects in vivo.

Black vinegar (BV) contains abundant essential and hydrophobic amino acids, and polyphenolic contents, especially catechin and chlorogenic acid via chemical analyses. K and Mg are the major minerals in BV, and Ca, Fe, Mn, and Se are also measured. After a 9-week experiment, high-fat/cholesterol-diet (HFCD) fed hamsters had higher (p<0.05) weight gains, relative visceral-fat sizes, serum/liver lipids, and serum cardiac indices than low-fat/cholesterol diet (LFCD) fed ones, but BV supplementation decreased (p<0.05) them which may resulted from the higher (p<0.05) faecal TAG and TC contents. Serum ALT value, and hepatic thiobarbituric acid reactive substances (TBARS), and hepatic TNF-α and IL-1ß contents in HFCD-fed hamsters were reduced (p<0.05) by supplementing BV due to increased (p<0.05) hepatic glutathione (GSH) and trolox equivalent antioxidant capacity (TEAC) levels, and catalase (CAT) and glutathione peroxidase (GPx) activities. Taken together, the component profiles of BV contributed the lipid lowering and antioxidant effects on HFCD fed hamsters.

Canonical Wnt signaling induces vascular endothelial dysfunction via p66Shc-regulated reactive oxygen species.

OBJECTIVE: Reactive oxygen species regulate canonical Wnt signaling. However, the role of the redox regulatory protein p66(Shc) in the canonical Wnt pathway is not known. We investigated whether p66(Shc) is essential for canonical Wnt signaling in the endothelium and determined whether the canonical Wnt pathway induces vascular endothelial dysfunction via p66(Shc)-mediated oxidative stress. APPROACH AND RESULTS: The canonical Wnt ligand Wnt3a induced phosphorylation (activation) of p66(Shc) in endothelial cells. Wnt3a-stimulated dephosphorylation of ß-catenin, and ß-catenin-dependent transcription, was inhibited by knockdown of p66(Shc). Exogenous H2O2-induced ß-catenin dephosphorylation was also mediated by p66(Shc). Moreover, p66(Shc) overexpression dephosphorylated ß-catenin and increased ß-catenin-dependent transcription, independent of Wnt3a ligand. P66(Shc)-induced ß-catenin dephosphorylation was inhibited by antioxidants N-acetyl cysteine and catalase. Wnt3a upregulated endothelial NADPH oxidase-4, and ß-catenin dephosphorylation was suppressed by knocking down NADPH oxidase-4 and by antioxidants. Wnt3a increased H2O2 levels in endothelial cells and impaired endothelium-dependent vasorelaxation in mouse aortas, both of which were rescued by p66(Shc) knockdown. P66(Shc) knockdown also inhibited adhesion of monocytes to Wnt3a-stimulated endothelial cells. Furthermore, constitutively active ß-catenin expression in the endothelium increased vascular reactive oxygen species and impaired endothelium-dependent vasorelaxation. In vivo, high-fat diet feeding-induced endothelial dysfunction in mice was associated with increased endothelial Wnt3a, dephosphorylated ß-catenin, and phosphorylated p66(Shc). High-fat diet-induced dephosphorylation of endothelial ß-catenin was diminished in mice in which p66(Shc) was knocked down. CONCLUSIONS: p66(Shc) plays a vital part in canonical Wnt signaling in the endothelium and mediates Wnt3a-stimulated endothelial oxidative stress and dysfunction.

Myeloid cell microsomal prostaglandin E synthase-1 fosters atherogenesis in mice.

Microsomal prostaglandin E synthase-1 (mPGES-1) in myeloid and vascular cells differentially regulates the response to vascular injury, reflecting distinct effects of mPGES-1-derived PGE2 in these cell types on discrete cellular components of the vasculature. The cell selective roles of mPGES-1 in atherogenesis are unknown. Mice lacking mPGES-1 conditionally in myeloid cells (Mac-mPGES-1-KOs), vascular smooth muscle cells (VSMC-mPGES-1-KOs), or endothelial cells (EC-mPGES-1-KOs) were crossed into hyperlipidemic low-density lipoprotein receptor-deficient animals. En face aortic lesion analysis revealed markedly reduced atherogenesis in Mac-mPGES-1-KOs, which was concomitant with a reduction in oxidative stress, reflective of reduced macrophage infiltration, less lesional expression of inducible nitric oxide synthase (iNOS), and lower aortic expression of NADPH oxidases and proinflammatory cytokines. Reduced oxidative stress was reflected systemically by a decline in urinary 8,12-iso-iPF2α-VI. In contrast to exaggeration of the response to vascular injury, deletion of mPGES-1 in VSMCs, ECs, or both had no detectable phenotypic impact on atherogenesis. Macrophage foam cell formation and cholesterol efflux, together with plasma cholesterol and triglycerides, were unchanged as a function of genotype. In conclusion, myeloid cell mPGES-1 promotes atherogenesis in hyperlipidemic mice, coincident with iNOS-mediated oxidative stress. By contrast, mPGES-1 in vascular cells does not detectably influence atherogenesis in mice. This strengthens the therapeutic rationale for targeting macrophage mPGES-1 in inflammatory cardiovascular diseases.

Hypotriglyceridemic effects of apple polyphenols extract via up-regulation of lipoprotein lipase in triton WR-1339-induced mice.

OBJECTIVE: To investigate the anti-hyperlipidemic effects of apple polyphenols extract (APE) in Triton WR-1339-induced endogenous hyperlipidemic model. METHODS: Firstly, APE was isolated and purified from the pomace of Red Fuji Apple and contents of individual polyphenols in APE were determined using high-performance liquid chromatography-mass spectrometry (HPLC-MS). Secondly, forty male National Institude of Health (NIH) mice were randomly divided into 5 groups with 8 animals in each group. The Fenofibrate Capsules (FC) group and APE groups received oral administration of respective drugs for 7 consecutive days. All mice except those in the normal group were intravenously injected through tail vein with Triton WR-1339 on the 6th day. Serum and livers from all the mice were obtained 18 h after the injection. The changes in serum total cholesterol (TC), triglyceride (TG), lipoprotein lipase (LPL) and hepatic triglyceride lipase (HTGL) were measured by respective kits. Finally, expression of hepatic peroxisome proliferator-activated receptor alpha (PPARα) mRNA was measured by real-time reverse transcription-polymerase chain reaction (RT-PCR) method. RESULTS SERUM TC AND TG LEVELS SIGNIFICANTLY INCREASED IN TRITON WR-1339-INDUCED MODEL GROUP COMPARED WITH THE NORMAL GROUP (P<0.01). ORAL ADMINISTRATION OF APE [200 AND 400 MG/(KG DAY)] DOSE-DEPENDENTLY REDUCED THE SERUM LEVEL OF TG IN HYPERLIPIDEMIC MICE (P<0.01). SERUM LPL AND HTGL ACTIVITIES SIGNIFICANTLY DECREASED IN TRITON WR-1339-INDUCED MODEL GROUP COMPARED WITH THE NORMAL GROUP (P<0.05). ORAL ADMINISTRATION OF APE [200 AND 400 MG/(KG DAY)] DOSE-DEPENDENTLY ELEVATED THE SERUM ACTIVITY OF LPL IN HYPERLIPIDEMIC MICE (P<0.05 OR P<0.01). FURTHERMORE, COMPARED WITH THE NORMAL GROUP, HEPATIC MRNA LEVEL OF PPARα IN THE MODEL GROUP SIGNIFICANTLY DECREASED (P<0.01). ORAL ADMINISTRATION OF APE [200 AND 400 MG/(KG DAY)] DOSE-DEPENDENTLY ELEVATED THE EXPRESSION OF PPARα IN HYPERLIPIDEMIC MICE (P<0.05 OR P<0.01): CONCLUSION: APE could reduce TG level via up-regulation of LPL activity, which provides new evidence to elucidate the anti-hyperlipidemic effects of APE.

Inflammatory stress induces statin resistance by disrupting 3-hydroxy-3-methylglutaryl-CoA reductase feedback regulation.

OBJECTIVE: The risk of cardiovascular disease is increased by up to 33 to 50× in chronic inflammatory states and convention doses of statins may not provide the same cardiovascular protection as in noninflamed patients. This study investigated whether the increase in 3-hydroxy-3-methylglutaryl-CoA reductase (HMGCoA-R)-mediated cholesterol synthesis observed under inflammatory stress was resistant to the action of statins and if so, whether this was because of interference with the sterol regulatory element binding protein cleavage-activating protein pathway. APPROACH AND RESULTS: Inflammatory stress was induced by adding cytokines (interleukin-1ß, tumor necrosis factor-α, and interleukin-6) and lipopolysaccharides to vascular smooth muscle cells in vitro and by subcutaneous casein injection in apolipoprotein E/scavenger receptors class A/CD36 triple knockout mice in vivo. Inflammatory stress exacerbated cholesterol ester accumulation and was accompanied in vitro and in vivo by increased HMGCoA-R mRNA and protein expression mediated via activation of the sterol regulatory element binding protein cleavage-activating protein/sterol regulatory element binding protein-2 pathway. Atorvastatin reduced HMGCoA-R enzymatic activity and intracellular cholesterol synthesis in vitro. However, inflammatory stress weakened these suppressive effects. Atorvastatin at concentrations of 16 µmol/L inhibited HMGCoA-R activity by 50% in vascular smooth muscle cells, but the same concentration resulted in only 30% of HMGCoA-R activity in vascular smooth muscle cells in the presence of interleukin-1ß. Knocking down sterol regulatory element binding protein cleavage-activating protein prevented statin resistance induced by interleukin-1ß, and overexpression of sterol regulatory element binding protein cleavage-activating protein induced statin resistance even without inflammatory stress. In vivo, the amount of atorvastatin required to lower serum cholesterol and decrease aortic lipid accumulation rose from 2 to 10 mg/kg per day in the presence of inflammatory stress. CONCLUSIONS: Increased cholesterol synthesis mediated by HMGCoA-R under inflammatory stress may be one of the mechanisms for intracellular lipid accumulation and statin resistance.

Enzimas antioxidantes en la hiperglicemia e hiperlipidemia inducida por sacarosa en ratas Wistar / Antioxidant enzymes in saccharose-induced hyperglycemia and hyperlipidemia in Wistar rats

El trabajo realizado evaluó la actividad de las enzimas antioxidantes catalasa y superóxido dismutasa en un modelo experimental de hiperlipidemia inducida por sacarosa en ratas Wistar, para lo cual se determinaron los niveles de glicemia y lípidos plasmáticos y los niveles de actividad enzimática específica de la superóxido dismutasa y la catalasa. Se produjeron incrementos significativos en los niveles de glicemia y triacilglicéridos relacionados con la dieta rica en sacarosa. Al cuarto mes del estudio se observó un incremento en la actividad de las enzimas en el grupo con dieta rica en sacarosa, solo con incrementos significativos para la catalasa. Se observó una fuerte correlación entre los niveles de triacilglicéridos del grupo estudio en el último mes de experimentación y los valores obtenidos en la actividad enzimática de la catalasa.

The work we accomplished evaluated the activity of the catalase antioxidant and dismutase superoxide enzymes in the experimental model of saccharose induced hyperlipidemia in Wistar rats, for what we determined the glicemia and plasmatic fluids and the levels of dismutase superoxide and catalase specific enzymatic activity. There they were significant increases in glicemia and triacylglycerides related with a saccharose-rich diet. At the fourth month of the study we observed an increase of the enzymes in the group with a saccharose-rich diet, with significant increases only for the catalase. It was observed a strong correlation between the triacylglyceride levels of the studied group in the last month of experimentation and the values obtained in the catalase enzymatic activity.