Replacement of Dietary Saturated Fat by PUFA-Rich Pumpkin Seed Oil Attenuates Non-Alcoholic Fatty Liver Disease and Atherosclerosis Development, with Additional Health Effects of Virgin over Refined Oil.

BACKGROUND AND AIMS: 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. METHODS: 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). RESULTS: 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. CONCLUSIONS: 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.

Mirtoselect, an anthocyanin-rich bilberry extract, attenuates non-alcoholic steatohepatitis and associated fibrosis in ApoE(∗)3Leiden mice.

BACKGROUND & AIMS: Anthocyanins may have beneficial effects on lipid metabolism and inflammation and are demonstrated to have hepatoprotective properties in models of restraint-stress- and chemically-induced liver damage. However, their potential to protect against non-alcoholic steatohepatitis (NASH) under conditions relevant for human pathogenesis remains unclear. Therefore, we studied the effects of the standardised anthocyanin-rich extract Mirtoselect on diet-induced NASH in a translational model of disease. METHODS: ApoE(∗)3Leiden mice were fed a Western-type cholesterol-containing diet without (HC) or with 0.1% (w/w) Mirtoselect (HCM) for 20weeks to study the effects on diet-induced NASH. RESULTS: Mirtoselect attenuated HC-induced hepatic steatosis, as observed by decreased macro- and microvesicular hepatocellular lipid accumulation and reduced hepatic cholesteryl ester content. This anti-steatotic effect was accompanied by local anti-inflammatory effects in liver, as demonstrated by reduced inflammatory cell clusters and reduced neutrophil infiltration in HCM. On a molecular level, HC diet significantly induced hepatic expression of pro-inflammatory genes Tnf, Emr1, Ccl2, Mpo, Cxcl1, and Cxcl2 while this induction was less pronounced or significantly decreased in HCM. A similar quenching effect was observed for HC-induced pro-fibrotic genes, Acta2 and Col1a1 and this anti-fibrotic effect of Mirtoselect was confirmed histologically. Many of the pro-inflammatory and pro-fibrotic parameters positively correlated with intrahepatic free cholesterol levels. Mirtoselect significantly reduced accumulation and crystallisation of intrahepatic free cholesterol, providing a possible mechanism for the observed hepatoprotective effects. CONCLUSIONS: Mirtoselect attenuates development of NASH, reducing hepatic lipid accumulation, inflammation and fibrosis, possibly mediated by local anti-inflammatory effects associated with reduced accumulation and crystallisation of intrahepatic free cholesterol.

Effects of chocolate supplementation on metabolic and cardiovascular parameters in ApoE3L mice fed a high-cholesterol atherogenic diet.

SCOPE: Dietary intake of cocoa and/or chocolate has been suggested to exhibit protective cardiovascular effects although this is still controversial. The aim of this study was to investigate the effects of chocolate supplementation on metabolic and cardiovascular parameters. METHODS AND RESULTS: Four groups of ApoE*3Leiden mice were exposed to the following diet regimens. Group 1: cholesterol-free control diet (CO). Group 2: high-dose (1.0% w/w) control cholesterol (CC). Group 3: CC supplemented chocolate A (CCA) and Group 4: CC supplemented chocolate B (CCB). Both chocolates differed in polyphenol and fiber content, CCA had a relatively high-polyphenol and low-fiber content compared to CCB. Mice fed a high-cholesterol diet showed increased plasma-cholesterol and developed atherosclerosis. Both chocolate treatments, particularly CCA, further increased plasma-cholesterol and increased atherosclerotic plaque formation. Moreover, compared to mice fed a high-cholesterol diet, both chocolate-treated groups displayed increased liver injury. Mice on high-cholesterol diet had elevated plasma levels of sVCAM-1, sE-selectin and SAA, which was further increased in the CCB group. Similar effects were observed for renal inflammation markers. CONCLUSION: The two chocolate preparations showed unfavorable, but different effects on cardiometabolic health in E3L mice, which dissimilarities may be related to differences in chocolate composition. We conclude that discrepancies reported on the effects of chocolate on cardiometabolic health may at least partly be due to differences in chocolate composition.

Arachidonic acid/docosahexaenoic acid-supplemented diet in early life reduces body weight gain, plasma lipids, and adiposity in later life in ApoE*3Leiden mice.

SCOPE: This study addresses whether early life arachidonic acid (ARA)/docosahexaenoic acid (DHA) supplementation or eicosapentaenoic acid (EPA)/DHA (Omacor) supplementation affects body weight gain, lipid metabolism, and adipose tissue quantity and quality in later life in ApoE*3Leiden-transgenic mice, a humanized model for hyperlipidemia and mild obesity. METHODS AND RESULTS: Four-week-old male ApoE*3Leiden mice were fed chow diet with or without a mixture of ARA (0.129 wt%) and DHA (0.088 wt%) or Omacor (0.30 wt% EPA, 0.25 wt% DHA). At age 12 weeks, mice were fed high-fat/high-carbohydrate (HFHC) diet without above supplements until age 20 weeks. Control mice received chow diet throughout the study. Mice receiving ARA/DHA gained less body weight compared to control and this effect was sustained when fed HFHC. Omacor had no significant effect on body weight gain. Plasma cholesterol and triglycerides were significantly lowered by both supplementations. At 20 weeks, epididymal fat mass was less in ARA/DHA-supplemented mice, while Omacor had no significant effect on fat mass. Both ARA/DHA and Omacor reduced inguinal adipocyte cell size; only ARA/DHA significantly reduced epididymal macrophage infiltration. CONCLUSION: This study shows that early life ARA/DHA, but not Omacor supplementation improves body weight gain later in life. ARA/DHA and to a lesser extent Omacor both improved adipose tissue quality.

Anti-inflammatory, anti-proliferative and anti-atherosclerotic effects of quercetin in human in vitro and in vivo models.

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 H(2)O(2)-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 IL1ß-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.

A dietary mixture containing fish oil, resveratrol, lycopene, catechins, and vitamins E and C reduces atherosclerosis in transgenic mice.

Chronic inflammation and proatherogenic lipids are important risk factors of cardiovascular disease (CVD). Specific dietary constituents such as polyphenols and fish oils may improve cardiovascular risk factors and may have a beneficial effect on disease outcomes. We hypothesized that the intake of an antiinflammatory dietary mixture (AIDM) containing resveratrol, lycopene, catechin, vitamins E and C, and fish oil would reduce inflammatory risk factors, proatherogenic lipids, and endpoint atherosclerosis. AIDM was evaluated in an inflammation model, male human C-reactive protein (CRP) transgenic mice, and an atherosclerosis model, female ApoE*3Leiden transgenic mice. Two groups of male human-CRP transgenic mice were fed AIDM [0.567% (wt:wt) powder and 0.933% (wt:wt oil)] or placebo for 6 wk. The effects of AIDM on basal and IL-1ß-stimulated CRP expression were investigated. AIDM reduced cytokine-induced human CRP and fibrinogen expression in human-CRP transgenic mice. In the atherosclerosis study, 2 groups of female ApoE*3Leiden transgenic mice were fed an atherogenic diet supplemented with AIDM [0.567% (wt:wt) powder and 0.933% (wt:wt oil)] or placebo for 16 wk. AIDM strongly reduced plasma cholesterol, TG, and serum amyloid A concentrations compared with placebo. Importantly, long-term treatment of ApoE*3Leiden mice with AIDM markedly reduced the development of atherosclerosis by 96% compared with placebo. The effect on atherosclerosis was paralleled by a reduced expression of the vascular inflammation markers and adhesion molecules inter-cellular adhesion molecule-1 and E-selectin. Dietary supplementation of AIDM improves lipid and inflammatory risk factors of CVD and strongly reduces atherosclerotic lesion development in female transgenic mice.

Anti-inflammatory salicylate beneficially modulates pre-existing atherosclerosis through quenching of NF-κB activity and lowering of cholesterol.

OBJECTIVE: Inflammation plays an important role in all stages of atherosclerosis, but little is known about the therapeutic effects of quenching inflammation in already existing atherosclerotic lesions. Putative beneficial effects of salicylate, an inhibitor of NF-κB activation, were studied in mice with established lesions. METHODS: ApoE*3-Leiden mice received a high-cholesterol diet (HC) to establish atherosclerotic lesions. Reference mice (REF) were sacrificed to determine the lesion area at the start of two interventions. In one intervention group HC diet feeding was continued, but the diet contained salicylate (HC+SAL). As salicylate not only quenches inflammation but also reduces plasma cholesterol, a second intervention group was fed a low-cholesterol diet (LC) resulting in cholesterol levels comparable to HC+SAL. The effects of these interventions on lesion area and composition were assessed after 8 and 16 weeks. RESULTS: HC+SAL markedly reduced hepatic NF-κB activity compared to REF, and was significantly more effective than LC diet feeding. HC+SAL and LC also quenched aortic NF-κB activity. While continuing HC diet typically further increases total lesion area, 16 weeks of intervention with HC+SAL and LC halted further disease progression and resulted in lesion sizes comparable to that of REF. At the same time, lesion composition was significantly improved, particularly with salicylate. Strikingly, HC+SAL resulted in a lower lesional macrophage content and a greater plaque stability index (ratio of collagen to macrophage area) than LC. CONCLUSION: Anti-inflammatory salicylate reduces atherosclerotic macrophage content and increases lesion stability of pre-existing plaques through quenching of NF-κB activity and reducing plasma cholesterol.

Central amylin acts as an adiposity signal to control body weight and energy expenditure.

The pancreatic B-cell hormone amylin has been proposed to be both a satiation signal and an adiposity signal. The effects of peripheral amylin on energy balance are well investigated, but the effects of central amylin are less clear. We determined the effects of low doses of amylin administered into the 3rd cerebral ventricle (i3vt) on food intake, body weight and other indices of energy balance. Amylin (2 pmol/h) significantly lowered body weight compared to saline after 2 weeks of infusion, independent of whether prior body weight was decreased by fasting, increased by voluntary overfeeding or unmanipulated. A bolus injection of amylin (10 pmol, i3vt) increased energy expenditure and body temperature, whereas chronic i3vt amylin infusion had no effect on energy expenditure above that of control rats even though body temperature was increased. Chronic amylin also reduced RQ, implying a preferential oxidation of fat. Overall, the data provide new evidence that amylin is an adiposity signal that acts within the brain, and informing the brain about the status of peripheral energy stores.

Vaccination against GIP for the treatment of obesity.

BACKGROUND: According to the WHO, more than 1 billion people worldwide are overweight and at risk of developing chronic illnesses, including cardiovascular disease, type 2 diabetes, hypertension and stroke. Current therapies show limited efficacy and are often associated with unpleasant side-effect profiles, hence there is a medical need for new therapeutic interventions in the field of obesity. Gastric inhibitory peptide (GIP, also known as glucose-dependent insulinotropic polypeptide) has recently been postulated to link over-nutrition with obesity. In fact GIP receptor-deficient mice (GIPR(-/-)) were shown to be completely protected from diet-induced obesity. Thus, disrupting GIP signaling represents a promising novel therapeutic strategy for the treatment of obesity. METHODOLOGY/PRINCIPAL FINDINGS: In order to block GIP signaling we chose an active vaccination approach using GIP peptides covalently attached to virus-like particles (VLP-GIP). Vaccination of mice with VLP-GIP induced high titers of specific antibodies and efficiently reduced body weight gain in animals fed a high fat diet. The reduction in body weight gain could be attributed to reduced accumulation of fat. Moreover, increased weight loss was observed in obese mice vaccinated with VLP-GIP. Importantly, despite the incretin action of GIP, VLP-GIP-treated mice did not show signs of glucose intolerance. CONCLUSIONS/SIGNIFICANCE: This study shows that vaccination against GIP was safe and effective. Thus active vaccination may represent a novel, long-lasting treatment for obesity. However further preclinical safety/toxicology studies will be required before the therapeutic concept can be addressed in humans.

In-vitro and in-vivo antagonistic action of an anti-amylin Spiegelmer.

The anorectic and dipsogenic effects of the pancreatic hormone amylin are mediated by the area postrema and the subfornical organ. We tested the effectiveness of a new amylin antagonist, a so-called RNA Spiegelmer, by electrophysiological in-vitro recordings from the rat subfornical organ and by immunohistological c-Fos studies in the area postrema. Amylin's excitatory effect on subfornical organ neurons was blocked by the anti-amylin Spiegelmer. Peripheral administration 5 h prior to amylin also suppressed the amylin-induced activation (c-Fos expression) in the area postrema. The biostable anti-amylin Spiegelmer may be therapeutically beneficial in conditions associated with high plasma amylin levels, such as cancer anorexia occurring during certain pancreatic tumors.

The acute effect of amylin and salmon calcitonin on energy expenditure.

The pancreatic B-cell hormone amylin is known to be involved in the regulation of meal ending satiation and it also shares typical features of adiposity signals. Chronic amylin administration has recently been shown to increase energy expenditure under certain conditions. Here we investigate the acute effect of peripheral administration of amylin or its agonist salmon calcitonin (sCT) on energy expenditure and respiratory quotient (RQ). First, rats were injected with amylin (5 microg/kg IP) or saline just before dark onset. Despite significantly decreased food intake in amylin-treated rats compared to control until 2 h post-injection (p<0.05), amylin did not influence energy expenditure or RQ. Reduced food intake, which reduces energy expenditure, may have confounded a stimulatory effect of amylin on energy expenditure. Therefore, in the second experiment, amylin (1, 5 and 10 microg/kg IP) or saline was injected in the middle of the light phase (t=0 h) without access to food during 3 h post-injection. Amylin had no significant effects on energy expenditure or RQ. In a similar paradigm, the effect of sCT (0.1, 1.0 and 5.0 microg/kg IP) was tested. During food restriction, 5.0 microg/kg sCT significantly stimulated energy expenditure compared to control (p<0.05). Subsequent to refeeding at t=3 h, energy expenditure was decreased compared to control at t=8 h and t=10 h after 5.0 microg/kg sCT, probably due to sCT's strong anorectic action. Thus amylin may prevent the compensatory decrease in energy expenditure normally seen in animals that eat less. The longer acting sCT stimulated energy expenditure in animals without food access.