Abstract Objective Polyphenols such as quercetin may exert several beneficial effects, including those resulting from anti-inflammatory activities, but their impact on cardiovascular health is ...debated. We investigated the effect of quercetin on cardiovascular risk markers including human C-reactive protein (CRP) and on atherosclerosis using transgenic humanized models of cardiovascular disease. Methods After evaluating its anti-oxidative and anti-inflammatory effects in cultured human cells, quercetin (0.1%, w/w in diet) was given to human CRP transgenic mice, a humanized inflammation model, and ApoE*3Leiden transgenic mice, a humanized atherosclerosis model. Sodium salicylate was used as an anti-inflammatory reference. Results In cultured human endothelial cells, quercetin protected against H2 O2 -induced lipid peroxidation and reduced the cytokine-induced cell-surface expression of VCAM-1 and E-selectin. Quercetin also reduced the transcriptional activity of NFκB in human hepatocytes. In human CRP transgenic mice (quercetin plasma concentration: 12.9 ± 1.3 μM), quercetin quenched IL1β-induced CRP expression, as did sodium salicylate. In ApoE*3Leiden mice, quercetin (plasma concentration: 19.3 ± 8.3 μM) significantly attenuated atherosclerosis by 40% (sodium salicylate by 86%). Quercetin did not affect atherogenic plasma lipids or lipoproteins but it significantly lowered the circulating inflammatory risk factors SAA and fibrinogen. Combined histological and microarray analysis of aortas revealed that quercetin affected vascular cell proliferation thereby reducing atherosclerotic lesion growth. Quercetin also reduced the gene expression of specific factors implicated in local vascular inflammation including IL-1R, Ccl8, IKK, and STAT3. Conclusion Quercetin reduces the expression of human CRP and cardiovascular risk factors (SAA, fibrinogen) in mice in vivo . These systemic effects together with local anti-proliferative and anti-inflammatory effects in the aorta may contribute to the attenuation of atherosclerosis.
Abstract Background and aims Besides LDL-cholesterol, local vascular inflammation plays a key role in atherogenesis. Efficient therapies to treat the inflammatory component of the disease have not ...been established. The discovery of specialized inflammation-resolving mediators, such as resolvins may provide new opportunities for treatment. This study examines whether the ω-3 fatty acid eicosapentaenoic acid-derived resolvin E1 (RvE1), can reduce atherosclerosis, when administered alone or in combination with a cholesterol-lowering statin. Methods ApoE*3Leiden mice were fed a hypercholesterolemic diet for 9 weeks and subsequently treated with RvE1-low (1 mg/kg/day), RvE1-high (5 mg/kg/day), atorvastatin (1.5 mg/kg/day) or the combination of atorvastatin and RvE1-low for the following 16 weeks. Results RvE1-low and RvE1-high reduced atherosclerotic lesion size to the same extent (−35%; p < 0.05), attenuated the formation of severe lesions, also seen as a proportional increase in the presence of mild lesions, but did not alter plasma cholesterol levels. Cholesterol-lowering atorvastatin reduced atherosclerosis (−27%, p < 0.05), and the combination of RvE1 and atorvastatin further attenuated lesion size (−51%, p < 0.01) and increased the content of mild lesions. RvE1 did not affect plasma SAA, E-selectin, VCAM-1 or MCP-1 but did reduce plasma EPHX4 and down-regulated the local expression of pro-atherogenic genes in the aortae, (e.g. Cd74 , Cd44 , Ccl2 , Ccr5 and Adam17 ) and significantly inactivated IFN-γ ( p < 0.001) and TNF-α ( p < 0.001) signalling pathways. Conclusions RvE1 attenuates atherogenesis both alone and on top of a statin. The local effects of RvE1 are demonstrated by the modulated aortic expression of genes involved in inflammatory and immune responses, without altering plasma cholesterol or circulating SAA.
Atherosclerosis is a multifactorial highly-complex disease with numerous etiologies that work synergistically to promote lesion development. The ability to develop preventive and ameliorative ...treatments will depend on animal models that mimic the human subject metabolically and pathophysiologically and will develop lesions comparable to those in humans. The mouse is the most useful, economic, and valid model for studying atherosclerosis and exploring effective therapeutic approaches. Among the most widely used mouse models for atherosclerosis are apolipoprotein E–deficient (ApoE) and LDL receptor–deficient (LDLr) mice. An up-and-coming model is the ApoE*3Leiden (E3L) transgenic mouse. Here, we review studies that have explored how and to what extent these mice respond to compounds directed at treatment of the risk factors hypercholesterolemia, hypertriglyceridemia, hypertension, and inflammation. An important outcome of this survey is that the different models used may differ markedly from one another in their response to a specific experimental manipulation. The choice of a model is therefore of critical importance and should take into account the risk factor to be studied and the working spectrum of the compounds tested.
The cytokine macrophage migration inhibitory factor (MIF) plays a critical role in inflammatory diseases and atherogenesis. We identify the chemokine receptors CXCR2 and CXCR4 as functional receptors ...for MIF. MIF triggered G(alphai)- and integrin-dependent arrest and chemotaxis of monocytes and T cells, rapid integrin activation and calcium influx through CXCR2 or CXCR4. MIF competed with cognate ligands for CXCR4 and CXCR2 binding, and directly bound to CXCR2. CXCR2 and CD74 formed a receptor complex, and monocyte arrest elicited by MIF in inflamed or atherosclerotic arteries involved both CXCR2 and CD74. In vivo, Mif deficiency impaired monocyte adhesion to the arterial wall in atherosclerosis-prone mice, and MIF-induced leukocyte recruitment required Il8rb (which encodes Cxcr2). Blockade of Mif but not of canonical ligands of Cxcr2 or Cxcr4 in mice with advanced atherosclerosis led to plaque regression and reduced monocyte and T-cell content in plaques. By activating both CXCR2 and CXCR4, MIF displays chemokine-like functions and acts as a major regulator of inflammatory cell recruitment and atherogenesis. Targeting MIF in individuals with manifest atherosclerosis can potentially be used to treat this condition.
Celotno besedilo
Dostopno za:
DOBA, IJS, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
Obesity frequently associates with the development of non-alcoholic fatty liver disease (NAFLD) and atherosclerosis. Chronic inflammation in white adipose tissue (WAT) seems to be an important driver ...of these manifestations.
This study investigated a combination of an extensively hydrolyzed casein (eHC), docosahexaenoic acid (DHA), arachidonic acid (ARA), and Lactobacillus Rhamnosus GG (LGG) (together referred to as nutritional ingredients, NI) on the development of obesity, metabolic risk factors, WAT inflammation, NAFLD and atherosclerosis in high-fat diet-fed LDLr-/-.Leiden mice, a model that mimics disease development in humans.
LDLr-/-.Leiden male mice (n = 15/group) received a high-fat diet (HFD, 45 Kcal%) for 21 weeks with or without the NI (23.7% eHC, 0.083% DHA, 0.166% ARA; all w/w and 1x109 CFU LGG gavage 3 times/week). HFD and HFD+NI diets were isocaloric. A low fat diet (LFD, 10 Kcal%) was used for reference. Body weight, food intake and metabolic risk factors were assessed over time. At week 21, tissues were analyzed for WAT inflammation (crown-like structures), NAFLD and atherosclerosis. Effects of the individual NI components were explored in a follow-up experiment (n = 7/group).
When compared to HFD control, treatment with the NI strongly reduced body weight to levels of the LFD group, and significantly lowered (P<0.01) plasma insulin, cholesterol, triglycerides, leptin and serum amyloid A (P<0.01). NI also reduced WAT mass and inflammation. Strikingly, NI treatment significantly reduced macrovesicular steatosis, lobular inflammation and liver collagen (P<0.05), and attenuated atherosclerosis development (P<0.01). Of the individual components, the effects of eHC were most pronounced but could not explain the entire effects of the NI formulation.
A combination of eHC, ARA, DHA and LGG attenuates obesity and associated cardiometabolic diseases (NAFLD, atherosclerosis) in LDLr-/-.Leiden mice. The observed reduction of inflammation in adipose tissue and in the liver provides a rationale for these comprehensive health effects.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
We report a sensitive, generic method for quantitative profiling of bile acids and other endogenous metabolites in small quantities of various biological fluids and tissues. The method is based on a ...straightforward sample preparation, separation by reversed-phase high performance liquid-chromatography mass spectrometry (HPLC-MS) and electrospray ionisation in the negative ionisation mode (ESI−). Detection is performed in full scan using the linear ion trap Fourier transform mass spectrometer (LTQ-FTMS) generating data for many (endogenous) metabolites, not only bile acids. A validation of the method in urine, plasma and liver was performed for 17 bile acids including their taurine, sulfate and glycine conjugates. The method is linear in the 0.01–1
μM range. The accuracy in human plasma ranges from 74 to 113%, in human urine 77 to 104% and in mouse liver 79 to 140%. The precision ranges from 2 to 20% for pooled samples even in studies with large number of samples (
n
>
250). The method was successfully applied to a multi-compartmental APOE*3-Leiden mouse study, the main goal of which was to analyze the effect of increasing dietary cholesterol concentrations on hepatic cholesterol homeostasis and bile acid synthesis. Serum and liver samples from different treatment groups were profiled with the new method. Statistically significant differences between the diet groups were observed regarding total as well as individual bile acid concentrations.
Statins are thought to reduce vascular inflammation through lipid independent mechanisms. Evaluation of such an effect in atherosclerotic disease is complicated by simultaneous effects on lipid ...metabolism. Abdominal aortic aneurysms (AAA) are part of the atherosclerotic spectrum of diseases. Unlike atherosclerotic occlusive disease, AAA is not lipid driven, thus allowing direct evaluation of putative anti-inflammatory effects. The anti-inflammatory potency of increasing doses (0, 20 or 40 mg/day) simvastatin or atorvastatin was evaluated in 63 patients that were at least 6 weeks on statin therapy and who underwent open AAA repair. A comprehensive analysis using immunohistochemistry, mRNA and protein analyses was applied on aortic wall samples collected during surgery. The effect of statins on AAA growth was analyzed in a separate prospective study in incorporating 142 patients. Both statins equally effectively and dose-dependently reduced aortic wall expression of NFκB regulated mediators (i.e. IL-6 (P<0.001) and MCP-1 (P<0.001)); shifted macrophage polarization towards a M2 phenotype (P<0.0003); selectively reduced macrophage-related markers such as cathepsin K and S (P<0.009 and 0.0027 respectively), and ALOX5 (P<0.0009), and reduced vascular wall NFκB activity (40 mg/day group, P<0.016). No effect was found on other cell types. Evaluation of the clinical efficacy of statins to reduce AAA progression did not indicate an effect of statins on aneurysm growth (P<0.337). Hence, in the context of AAA the clinical relevance of statins pleiotropy appears minimal.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
The aim of this study was to define the anti-atherosclerotic role of liver-X-receptors (LXRs) under lesion progressive and lesion regressive conditions, to establish a temporal line of events, and to ...gain insights into the mechanisms underlying the anti-atherogenic potency of LXRs. We used apoE*3Leiden (E3L) mice to comprehensively and time-dependently dissect how T0901317, an LXR-agonist, inhibits initiation and progression of atherosclerotic lesions and regresses existing lipid- and macrophage-rich lesions. T0901317 suppresses lesion evolution and promotes lesion regression regarding lesion number, area, and severity. Quantitative plasma and vessel wall analyses corroborated by immunohistochemical evaluation of the aortic lesions revealed that under progressive (high-cholesterol diet) as well as regressive (cholesterol-free diet) conditions T0901317: i) significantly increases plasma triglyceride and total cholesterol levels; ii) does not affect the systemic inflammation marker, Serum amyloid A (SAA); iii) suppresses endothelial monocyte adhesion; and iv) induces the expression of the cholesterol efflux-related genes apolipoprotein E (apoE), ATP binding cassette (ABC) transporters ABCA1 and ABCG1. Furthermore, under progressive conditions, T0901317 suppresses the vascular inflammatory status (NF-κB) and the vascular expression of adhesion molecules E-selectin, intercellular adhesion molecule (ICAM)-1, and CD44, lowers lesional macrophage accumulation, and blocks lesion evolution at the transition from lesional stage II to III. Under regressive conditions, T0901317 induces lesional macrophage disappearance and increases the expression of the chemokine receptor CCR7, a factor functionally required for regression. The LXR-agonist T0901317 retards vascular lesion development and promotes lesion regression at several levels. The findings support that vascular LXR is a potential anti-atherosclerotic target.
As dietary saturated fatty acids are associated with metabolic and cardiovascular disease, a potentially interesting strategy to reduce disease risk is modification of the quality of fat consumed. ...Vegetable oils represent an attractive target for intervention, as they largely determine the intake of dietary fats. Furthermore, besides potential health effects conferred by the type of fatty acids in a vegetable oil, other minor components (e.g. phytochemicals) may also have health benefits. Here, we investigated the potential long-term health effects of isocaloric substitution of dietary fat (i.e. partial replacement of saturated by unsaturated fats), as well as putative additional effects of phytochemicals present in unrefined (virgin) oil on development of non-alcoholic fatty liver disease (NAFLD) and associated atherosclerosis. For this, we used pumpkin seed oil, because it is high in unsaturated fatty acids and a rich source of phytochemicals.
ApoE*3Leiden mice were fed a Western-type diet (CON) containing cocoa butter (15% w/w) and cholesterol (1% w/w) for 20 weeks to induce risk factors and disease endpoints. In separate groups, cocoa butter was replaced by refined (REF) or virgin (VIR) pumpkin seed oil (comparable in fatty acid composition, but different in phytochemical content).
Both oils improved dyslipidaemia, with decreased (V)LDL-cholesterol and triglyceride levels in comparison with CON, and additional cholesterol-lowering effects of VIR over REF. While REF did not affect plasma inflammatory markers, VIR reduced circulating serum amyloid A and soluble vascular adhesion molecule-1. NAFLD and atherosclerosis development was modestly reduced in REF, and VIR strongly decreased liver steatosis and inflammation as well as atherosclerotic lesion area and severity.
Overall, we show that an isocaloric switch from a diet rich in saturated fat to a diet rich in unsaturated fat can attenuate NAFLD and atherosclerosis development. Phytochemical-rich virgin pumpkin seed oil exerts additional anti-inflammatory effects resulting in more pronounced health effects.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
The sequence of events leading to the development of insulin resistance (IR) as well as the underlying pathophysiological mechanisms are incompletely understood. As reductionist approaches have been ...largely unsuccessful in providing an understanding of the pathogenesis of IR, there is a need for an integrative, time-resolved approach to elucidate the development of the disease.
Male ApoE3Leiden transgenic mice exhibiting a humanized lipid metabolism were fed a high-fat diet (HFD) for 0, 1, 6, 9, or 12 weeks. Development of IR was monitored in individual mice over time by performing glucose tolerance tests and measuring specific biomarkers in plasma, and hyperinsulinemic-euglycemic clamp analysis to assess IR in a tissue-specific manner. To elucidate the dynamics and tissue-specificity of metabolic and inflammatory processes key to IR development, a time-resolved systems analysis of gene expression and metabolite levels in liver, white adipose tissue (WAT), and muscle was performed. During HFD feeding, the mice became increasingly obese and showed a gradual increase in glucose intolerance. IR became first manifest in liver (week 6) and then in WAT (week 12), while skeletal muscle remained insulin-sensitive. Microarray analysis showed rapid upregulation of carbohydrate (only liver) and lipid metabolism genes (liver, WAT). Metabolomics revealed significant changes in the ratio of saturated to polyunsaturated fatty acids (liver, WAT, plasma) and in the concentrations of glucose, gluconeogenesis and Krebs cycle metabolites, and branched amino acids (liver). HFD evoked an early hepatic inflammatory response which then gradually declined to near baseline. By contrast, inflammation in WAT increased over time, reaching highest values in week 12. In skeletal muscle, carbohydrate metabolism, lipid metabolism, and inflammation was gradually suppressed with HFD.
HFD-induced IR is a time- and tissue-dependent process that starts in liver and proceeds in WAT. IR development is paralleled by tissue-specific gene expression changes, metabolic adjustments, changes in lipid composition, and inflammatory responses in liver and WAT involving p65-NFkB and SOCS3. The alterations in skeletal muscle are largely opposite to those in liver and WAT.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
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