The passive coping Roman Low Avoidance rat, a non-obese rat model for insulin resistance

The aim of the study was develop to an animal model that links coping style to insulin resistance. We hypothesized that the psychogenetically selected Roman Low Avoidance (RLA) rats may serve as such a model. To test this hypothesis, we submitted both RLA and Roman High avoidance (RHA) rats to a series of intravenous glucose tolerance tests (IVGTT). These IVGTT were followed by post mortem metabolic characterization of the selection lines. It was found that plasma insulin levels are markedly elevated in the passively coping RLA rat, both in baseline conditions and during the intravenous glucose tolerance tests. The elevation in plasma insulin was accompanied with increased levels of plasma corticosterone, FFA, leptin and triglycerides but not by changes in body weight. We conclude that the passive, highly emotional RLA rat is metabolically different from both the RHA rat and the standard control Wistar rat and may serve as a nonobese animal model for insulin resistance.

Comparison of the effects of three different (-)-hydroxycitric acid preparations on food intake in rats

BACKGROUND: Studies on the effects of (-)-hydroxycitric acid (HCA) in humans are controversial. As differences in the HCA preparations may contribute to this apparent discrepancy, the aim of the current study is to compare different HCA-containing preparations in adult Wistar rats. DESIGN: The effects of 3 different HCA-containing preparations (Regulator, Citrin K, Super CitriMax HCA-600-SXS, all used at an effective HCA dose of 150 and 300 mg/kg, administered intragastrically) on food intake and body weight were studied in adult male Wistar rats. The efficacy was tested under 2 different experimental conditions: 1) after a single dose administration and 2) during repeated administration for 4 subsequent days. RESULTS: Regulator and Citrin K significantly reduced food intake in both experimental setups, while Super CitriMax HCA-600-SXS was less effective. When administered for 4 subsequent days Regulator and Citrin K diminished body weight gain. CONCLUSION: Regulator and Citrin K were shown to be potent inhibitors of food intake in rats, whereas Super CitriMax HCA-600-SXS showed only small and more inconsistent effects. The striking differences in efficacy between these 3 preparations indicate that low doses of a relatively low-effective HCA preparation may have contributed to the lack of efficacy as found in several human studies

Surgical removal of inflamed epididymal white adipose tissue attenuates the development of non-alcoholic steatohepatitis in obesity

Vascular Surger

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 H2O2-induced lipid peroxidation and reduced the cytokine-induced cell-surface expression of VCAM-1 and E-selectin. Quercetin also reduced the transcriptional activity of NF?B in human hepatocytes. In human CRP transgenic mice (quercetin plasma concentration: 12.9±1.3µM), quercetin quenched IL1ß-induced CRP expression, as did sodium salicylate. In ApoE*3Leiden mice, quercetin (plasma concentration: 19.3±8.3µM) 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. © 2011 Elsevier Ireland Ltd

Resolvin E1 attenuates atherosclerosis in absence of cholesterol-lowering effects and on top of atorvastatin

Vascular Surger

Reduction of obesity-associated white adipose tissue inflammation by rosiglitazone is associated with reduced non-alcoholic fatty liver disease in LDLr-deficient mice

Obesity is associated with chronic low-grade inflammation that drives the development of metabolic diseases, including non-alcoholic fatty liver disease (NAFLD). We recently showed that white adipose tissue (WAT) constitutes an important source of inflammatory factors. Hence, interventions that attenuate WAT inflammation may reduce NAFLD development. Male LDLr-/- mice were fed a high-fat diet (HFD) for 9 weeks followed by 7 weeks of HFD with or without rosiglitazone. Effects on WAT inflammation and NAFLD development were analyzed using biochemical and (immuno)histochemical techniques, combined with gene expression analyses. Nine weeks of HFD feeding induced obesity and WAT inflammation, which progressed gradually until the end of the study. Rosiglitazone fully blocked progression of WAT inflammation and activated PPARγ significantly in WAT. Rosiglitazone intervention did not activate PPARγ in liver, but improved liver histology and counteracted the expression of genes associated with severe NAFLD in humans. Rosiglitazone reduced expression of pro-inflammatory factors in WAT (TNF-α, leptin) and increased expression of adiponectin, which was reflected in plasma. Furthermore, rosiglitazone lowered circulating levels of pro-inflammatory saturated fatty acids. Together, these observations provide a rationale for the observed indirect hepatoprotective effects and suggest that WAT represents a promising therapeutic target for the treatment of obesity-associated NAFLD

Arachidonic acid/docosahexaenoic acid-supplemented diet in early life reduces body weight gain, plasma lipids, and adiposity in later life in ApoE*3 Leiden 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 extentOmacor both improved adipose tissue quality

Anti-inflammatory salicylate beneficially modulates pre-existing atherosclerosis through quenching of NF-kappa B 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-kappa B 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-kappa B activity compared to REF, and was significantly more effective than LC diet feeding. HC + SAL and LC also quenched aortic NF-kappa B 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-kappa B activity and reducing plasma cholesterol. (C) 2010 Elsevier Ireland Ltd. All rights reserved.Diabetes mellitus: pathophysiological changes and therap

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.Diabetes mellitus: pathophysiological changes and therap