Translational characterization of the temporal dynamics of metabolic dysfunctions in liver, adipose tissue and the gut during diet-induced NASH development in Ldlr-/-.Leiden mice

Background

NAFLD progression, from steatosis to inflammation and fibrosis, results from an interplay of intra- and extrahepatic mechanisms. Disease drivers likely include signals from white adipose tissue (WAT) and gut. However, the temporal dynamics of disease development remain poorly understood.

Methods

High-fat-diet (HFD)-fed Ldlr-/-.Leiden mice were compared to chow-fed controls. At t = 0, 8, 16, 28 and 38w mice were euthanized, and liver, WAT depots and gut were analyzed biochemically, histologically and by lipidomics and transcriptomics together with circulating factors to investigate the sequence of pathogenic events and organ cross-talk during NAFLD development.

Results

HFD-induced obesity was associated with an increase in visceral fat, plasma lipids and hyperinsulinemia at t = 8w, along with increased liver steatosis and circulating liver damage biomarkers. In parallel, upstream regulator analysis predicted that lipid catabolism regulators were deactivated and lipid synthesis regulators were activated. Subsequently, hepatocyte hypertrophy, oxidative stress and hepatic inflammation developed. Hepatic collagen accumulated from t = 16 w and became pronounced at t = 28-38 w. Epididymal WAT was maximally hypertrophic from t = 8 w, which coincided with inflammation development. Mesenteric and subcutaneous WAT hypertrophy developed slower and did not appear to reach a maximum, with minimal inflammation. In gut, HFD significantly increased permeability, induced a shift in microbiota composition from t = 8 w and changed circulating gut-derived metabolites.

Conclusion

HFD-fed Ldlr-/-.Leiden mice develop obesity, dyslipidemia and insulin resistance, essentially as observed in obese NAFLD patients, underlining their translational value. We demonstrate that marked epididymal-WAT inflammation, and gut permeability and dysbiosis precede the development of NAFLD stressing the importance of a multiple-organ approach in the prevention and treatment of NAFLD.

Therapeutic Intervention with Anti-Complement Component 5 Antibody Does Not Reduce NASH but Does Attenuate Atherosclerosis and MIF Concentrations in Ldlr-/-.Leiden Mice

Background: Chronic inflammation is an important driver in the progression of non-alcoholic steatohepatitis (NASH) and atherosclerosis. The complement system, one of the first lines of defense in innate immunity, has been implicated in both diseases. However, the potential therapeutic value of complement inhibition in the ongoing disease remains unclear. Methods: After 20 weeks of high-fat diet (HFD) feeding, obese Ldlr-/-.Leiden mice were treated twice a week with an established anti-C5 antibody (BB5.1) or vehicle control. A separate group of mice was kept on a chow diet as a healthy reference. After 12 weeks of treatment, NASH was analyzed histopathologically, and genome-wide hepatic gene expression was analyzed by next-generation sequencing and pathway analysis. Atherosclerotic lesion area and severity were quantified histopathologically in the aortic roots. Results: Anti-C5 treatment considerably reduced complement system activity in plasma and MAC deposition in the liver but did not affect NASH. Anti-C5 did, however, reduce the development of atherosclerosis, limiting the total lesion size and severity independently of an effect on plasma cholesterol but with reductions in oxidized LDL (oxLDL) and macrophage migration inhibitory factor (MIF). Conclusion: We show, for the first time, that treatment with an anti-C5 antibody in advanced stages of NASH is not sufficient to reduce the disease, while therapeutic intervention against established atherosclerosis is beneficial to limit further progression.

Intervention with isoleucine or valine corrects hyperinsulinemia and reduces intrahepatic diacylglycerols, liver steatosis, and inflammation in Ldlr-/-.Leiden mice with manifest obesity-associated NASH

Non-alcoholic steatohepatitis (NASH) is associated with a disturbed metabolism in liver, insulin resistance, and excessive accumulation of ectopic fat. Branched-chain amino acids (BCAAs) may beneficially modulate hepatic lipids, however, it remains unclear whether individual BCAAs can attenuate already established NASH and associated oxidative-inflammatory stress. After a 26 weeks run-in on fast food diet (FFD), obese Ldlr-/-.Leiden mice were treated for another 12 weeks with either valine or isoleucine (3% of FFD) and then compared to FFD controls. Valine and isoleucine did not affect obesity, dyslipidemia, gut permeability, or fecal fatty acid excretion, but significantly reduced hyperinsulinemia. Valine and isoleucine reduced ALT, CK18-M30, and liver steatosis with a particularly pronounced suppression of the microvesicular component (-61% by valine and -71% by isoleucine). Both BCAAs decreased intrahepatic diacylglycerols and 4-hydroxynonenal immunoreactivity, a marker for oxidative stress-induced lipid peroxidation. Functional genomics analysis demonstrated that valine and isoleucine affected BCAA metabolism genes, deactivated master regulators of anabolic pathways related to steatosis (e.g., SREBPF1), and activated master regulators of mitochondrial biogenesis (e.g., PPARGC1A) and lipid catabolism (e.g., ACOX1, AMPK). This correction of critical metabolic pathways on gene expression level was accompanied by a significant decrease in histological liver inflammation, and suppression of FFD-stimulated cytokine and chemokine proteins KC/CXCL1, MCP-1/CCL2, and MIP-2/CXCL2 and their pathways. In conclusion, dietary intervention with either valine or isoleucine corrected liver diacylglycerols, gene expression of multiple metabolic processes, and reduced NASH histology with profound hepatoprotective effects on oxidative stress and inflammatory proteins.

Heat-Inactivated Akkermansia muciniphila Improves Gut Permeability but Does Not Prevent Development of Non-Alcoholic Steatohepatitis in Diet-Induced Obese Ldlr-/-.Leiden Mice

The development of non-alcoholic steatohepatitis (NASH) has been associated with alterations in gut microbiota composition and reduced gut barrier function. Akkermansia muciniphila is a gut microbe that is thought to have health-promoting properties, including the ability to improve gut barrier function and host metabolism, both when administered live and after heat-inactivation. We questioned whether heat-inactivated A. muciniphila may reduce NASH development. Ldlr−/−.Leiden mice, a translational, diet-induced model for NASH, were fed a NASH-inducing high-fat diet (HFD) supplemented with heat-inactivated A. muciniphila. After 28 weeks, effects of the treatment on obesity and associated metabolic dysfunction in the gut (microbiota composition and permeability), adipose tissue, and liver were studied relative to an untreated HFD control. Treatment with heat-inactivated A. muciniphila did not affect body weight or adiposity and had no effect on plasma lipids, blood glucose, or plasma insulin. Heat-inactivated A. muciniphila had some minor effects on mucosal microbiota composition in ileum and colon and improved gut barrier function, as assessed by an in vivo functional gut permeability test. Epidydimal white adipose tissue (WAT) hypertrophy and inflammation were not affected, but heat-inactivated A. muciniphila did reduce hypertrophy in the mesenteric WAT which is in close proximity to the intestine. Heat-inactivated A. muciniphila did not affect the development of NASH or associated fibrosis in the liver and did not affect circulating bile acids or markers of liver fibrosis, but did reduce PRO-C4, a type IV collagen synthesis marker, which may be associated with gut integrity. In conclusion, despite beneficial effects in the gut and mesenteric adipose tissue, heat-inactivated A. muciniphila did not affect the development of NASH and fibrosis in a chronic disease setting that mimics clinically relevant disease stages.

Butyrate Protects against Diet-Induced NASH and Liver Fibrosis and Suppresses Specific Non-Canonical TGF-β Signaling Pathways in Human Hepatic Stellate Cells

In obesity-associated non-alcoholic steatohepatitis (NASH), persistent hepatocellular damage and inflammation are key drivers of fibrosis, which is the main determinant of NASH-associated mortality. The short-chain fatty acid butyrate can exert metabolic improvements and anti-inflammatory activities in NASH. However, its effects on NASH-associated liver fibrosis remain unclear. Putative antifibrotic effects of butyrate were studied in Ldlr-/-.Leiden mice fed an obesogenic diet (HFD) containing 2.5% (w/w) butyrate for 38 weeks and compared with a HFD-control group. Antifibrotic mechanisms of butyrate were further investigated in TGF-β-stimulated primary human hepatic stellate cells (HSC). HFD-fed mice developed obesity, insulin resistance, increased plasma leptin levels, adipose tissue inflammation, gut permeability, dysbiosis, and NASH-associated fibrosis. Butyrate corrected hyperinsulinemia, lowered plasma leptin levels, and attenuated adipose tissue inflammation, without affecting gut permeability or microbiota composition. Butyrate lowered plasma ALT and CK-18M30 levels and attenuated hepatic steatosis and inflammation. Butyrate inhibited fibrosis development as demonstrated by decreased hepatic collagen content and Sirius-red-positive area. In TGF-β-stimulated HSC, butyrate dose-dependently reduced collagen deposition and decreased procollagen1α1 and PAI1 protein expression. Transcriptomic analysis and subsequent pathway and upstream regulator analysis revealed deactivation of specific non-canonical TGF-β signaling pathways Rho-like GTPases and PI3K/AKT and other important pro-fibrotic regulators (e.g., YAP/TAZ, MYC) by butyrate, providing a potential rationale for its antifibrotic effects. In conclusion, butyrate protects against obesity development, insulin resistance-associated NASH, and liver fibrosis. These antifibrotic effects are at least partly attributable to a direct effect of butyrate on collagen production in hepatic stellate cells, involving inhibition of non-canonical TGF-β signaling pathways.

Cholesterol Accumulation as a Driver of Hepatic Inflammation Under Translational Dietary Conditions Can Be Attenuated by a Multicomponent Medicine

BACKGROUND

Non-alcoholic fatty liver disease (NAFLD) is a complex multifactorial disorder that is characterised by dysfunctional lipid metabolism and cholesterol homeostasis, and a related chronic inflammatory response. NAFLD has become the most common cause of chronic liver disease in many countries, and its prevalence continues to rise in parallel with increasing rates of obesity. Here, we evaluated the putative NAFLD-attenuating effects of a multicomponent medicine consisting of 24 natural ingredients: Hepar compositum (HC-24).

METHODS

Ldlr-/-.Leiden mice were fed a high-fat diet (HFD) with a macronutrient composition and cholesterol content comparable to human diets for 24 weeks to induce obesity-associated metabolic dysfunction, including hepatic steatosis and inflammation. HC-24 or vehicle control was administered intraperitoneally 3 times/week (1.5 ml/kg) for the last 18 weeks of the study. Histological analyses of liver and adipose tissue were combined with extensive hepatic transcriptomics analysis. Transcriptomics results were further substantiated with ELISA, immunohistochemical and liver lipid analyses.

RESULTS

HFD feeding induced obesity and metabolic dysfunction including adipose tissue inflammation and increased gut permeability. In the liver, HFD-feeding resulted in a disturbance of cholesterol homeostasis and an associated inflammatory response. HC-24 did not affect body weight, metabolic risk factors, adipose tissue inflammation or gut permeability. While HC-24 did not alter total liver steatosis, there was a pronounced reduction in lobular inflammation in HC-24-treated animals, which was associated with modulation of genes and proteins involved in inflammation (e.g., neutrophil chemokine Cxcl1) and cholesterol homeostasis (i.e., predicted effect on 'cholesterol' as an upstream regulator, based on gene expression changes associated with cholesterol handling). These effects were confirmed by CXCL1 ELISA, immunohistochemical staining of neutrophils and biochemical analysis of hepatic free cholesterol content. Intrahepatic free cholesterol levels were found to correlate significantly with the number of inflammatory aggregates in the liver, thereby providing a potential rationale for the observed anti-inflammatory effects of HC-24.

CONCLUSIONS

Free cholesterol accumulates in the liver of Ldlr-/-.Leiden mice under physiologically translational dietary conditions, and this is associated with the development of hepatic inflammation. The multicomponent medicine HC-24 reduces accumulation of free cholesterol and has molecular and cellular anti-inflammatory effects in the liver.

Propionic acid and not caproic acid, attenuates nonalcoholic steatohepatitis and improves (cerebro) vascular functions in obese Ldlr-/- .Leiden mice

The obesity epidemic increases the interest to elucidate impact of short-chain fatty acids on metabolism, obesity, and the brain. We investigated the effects of propionic acid (PA) and caproic acid (CA) on metabolic risk factors, liver and adipose tissue pathology, brain function, structure (by MRI), and gene expression, during obesity development in Ldlr^-/- .Leiden mice. Ldlr^-/- .Leiden mice received 16 weeks either a high-fat diet (HFD) to induce obesity, or chow as reference group. Next, obese HFD-fed mice were treated 12 weeks with (a) HFD + CA (CA), (b) HFD + PA (PA), or (c) a HFD-control group. PA reduced the body weight and systolic blood pressure, lowered fasting insulin levels, and reduced HFD-induced liver macrovesicular steatosis, hypertrophy, inflammation, and collagen content. PA increased the amount of glucose transporter type 1-positive cerebral blood vessels, reverted cerebral vasoreactivity, and HFD-induced effects in microstructural gray and white matter integrity of optic tract, and somatosensory and visual cortex. PA and CA also reverted HFD-induced effects in functional connectivity between visual and auditory cortex. However, PA mice were more anxious in open field, and showed reduced activity of synaptogenesis and glutamate regulators in hippocampus. Therefore, PA treatment should be used with caution even though positive metabolic, (cerebro) vascular, and brain structural and functional effects were observed.

Combined Treatment with L-Carnitine and Nicotinamide Riboside Improves Hepatic Metabolism and Attenuates Obesity and Liver Steatosis

Obesity characterized by adiposity and ectopic fat accumulation is associated with the development of non-alcoholic fatty liver disease (NAFLD). Treatments that stimulate lipid utilization may prevent the development of obesity and comorbidities. This study evaluated the potential anti-obesogenic hepatoprotective effects of combined treatment with L-carnitine and nicotinamide riboside, i.e., components that can enhance fatty acid transfer across the inner mitochondrial membrane and increase nicotinamide adenine nucleotide (NAD+) levels, which are necessary for β-oxidation and the TCA cycle, respectively. Ldlr -/-.Leiden mice were treated with high-fat diet (HFD) supplemented with L-carnitine (LC; 0.4% w/w), nicotinamide riboside (NR; 0.3% w/w) or both (COMBI) for 21 weeks. L-carnitine plasma levels were reduced by HFD and normalized by LC. NR supplementation raised its plasma metabolite levels demonstrating effective delivery. Although food intake and ambulatory activity were comparable in all groups, COMBI treatment significantly attenuated HFD-induced body weight gain, fat mass gain (-17%) and hepatic steatosis (-22%). Also, NR and COMBI reduced hepatic 4-hydroxynonenal adducts. Upstream-regulator gene analysis demonstrated that COMBI reversed detrimental effects of HFD on liver metabolism pathways and associated regulators, e.g., ACOX, SCAP, SREBF, PPARGC1B, and INSR. Combination treatment with LC and NR exerts protective effects on metabolic pathways and constitutes a new approach to attenuate HFD-induced obesity and NAFLD.

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.

Differential effects of drug interventions and dietary lifestyle in developing type 2 diabetes and complications: a systems biology analysis in LDLr-/- mice

Excess caloric intake leads to metabolic overload and is associated with development of type 2 diabetes (T2DM). Current disease management concentrates on risk factors of the disease such as blood glucose, however with limited success. We hypothesize that normalizing blood glucose levels by itself is insufficient to reduce the development of T2DM and complications, and that removal of the metabolic overload with dietary interventions may be more efficacious. We explored the efficacy and systems effects of pharmaceutical interventions versus dietary lifestyle intervention (DLI) in developing T2DM and complications. To mimic the situation in humans, high fat diet (HFD)-fed LDLr-/- mice with already established disease phenotype were treated with ten different drugs mixed into HFD or subjected to DLI (switch to low-fat chow), for 7 weeks. Interventions were compared to untreated reference mice kept on HFD or chow only. Although most of the drugs improved HFD-induced hyperglycemia, drugs only partially affected other risk factors and also had limited effect on disease progression towards microalbuminuria, hepatosteatosis and atherosclerosis. By contrast, DLI normalized T2DM risk factors, fully reversed hepatosteatosis and microalbuminuria, and tended to attenuate atherogenesis. The comprehensive beneficial effect of DLI was reflected by normalized metabolite profiles in plasma and liver. Analysis of disease pathways in liver confirmed reversion of the metabolic distortions with DLI. This study demonstrates that the pathogenesis of T2DM towards complications is reversible with DLI and highlights the differential effects of current pharmacotherapies and their limitation to resolve the disease.

Identification of prognostic and diagnostic biomarkers of glucose intolerance in ApoE3Leiden mice

The prevalence of diabetes mellitus Type 2 could be significantly reduced by early identification of subjects at risk, allowing for better prevention and earlier treatment. Glucose intolerance (GI) is a hallmark of the prediabetic stage. This study aims at identifying 1) prognostic biomarkers predicting the risk of developing GI later in life and 2) diagnostic biomarkers reflecting the degree of already manifest GI. To this end, disease development was followed over time in mice, and biomarkers were identified using lipidomics and transcriptomics. Young adult ApoE3Leiden mice were treated a high-fat diet for 12 wk to induce GI. Blood was collected before and during disease development. The individual extent of GI was determined with a glucose tolerance test and the area under the curve (AUC) was calculated for each animal. Subject-specific AUC values were correlated to the plasma lipidome (t = 0) and the white blood cell (WBC) transcriptome (t = 0, 6, and 12 wk) to identify prognostic and diagnostic biomarkers, respectively. The plasma ratio of specific free fatty acids prior to high-fat feeding (C16:1/C16:0, C18:1/C18:0 and C18:2/C22:6) was significantly correlated with the AUC and predictive for future GI. Subsequently, the expression level of specific WBC genes (Acss2, Arfgap1, Tfrc, Cox6b2, Barhl2, Abcb4, Cyp4b1, Sars2, Fgf16, and Tceal8) reflected the individual degree of GI during disease progression. Specific plasma free fatty acids as well as their ratio can be used to predict future GI. The expression levels of specific WBC genes can serve as easy accessible markers to diagnose and monitor already existing GI.

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-1β-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.

Dietary sphingolipids lower plasma cholesterol and triacylglycerol and prevent liver steatosis in APOE*3Leiden mice

BACKGROUND

The prevalence of dyslipidemia and obesity resulting from excess energy intake and physical inactivity is increasing. The liver plays a pivotal role in systemic lipid homeostasis. Effective, natural dietary interventions that lower plasma lipids and promote liver health are needed.

OBJECTIVE

Our goal was to determine the effect of dietary sphingolipids on plasma lipids and liver steatosis.

DESIGN

APOE*3Leiden mice were fed a Western-type diet supplemented with different sphingolipids. Body cholesterol and triacylglycerol metabolism as well as hepatic lipid concentrations and lipid-related gene expression were determined.

RESULTS

Dietary sphingolipids dose-dependently lowered both plasma cholesterol and triacylglycerol in APOE*3Leiden mice; 1% phytosphingosine (PS) reduced plasma cholesterol and triacylglycerol by 57% and 58%, respectively. PS decreased the absorption of dietary cholesterol and free fatty acids by 50% and 40%, respectively, whereas intestinal triacylglycerol lipolysis was not affected. PS increased hepatic VLDL-triacylglycerol production by 20%, whereas plasma lipolysis was not affected. PS increased the hepatic uptake of VLDL remnants by 60%. Hepatic messenger RNA concentrations indicated enhanced hepatic lipid synthesis and VLDL and LDL uptake. The net result of these changes was a strong decrease in plasma cholesterol and triacylglycerol. The livers of 1% PS-fed mice were less pale, 22% lighter, and contained 61% less cholesteryl ester and 56% less triacylglycerol than livers of control mice. Furthermore, markers of liver inflammation (serum amyloid A) and liver damage (alanine aminotransferase) decreased by 74% and 79%, respectively, in PS-fed mice.

CONCLUSION

Sphingolipids lower plasma cholesterol and triacylglycerol and protect the liver from fat- and cholesterol-induced steatosis.

Rosuvastatin Reduces Plasma Lipids by Inhibiting VLDL Production and Enhancing Hepatobiliary Lipid Excretion in ApoE*3-Leiden Mice

The present study was designed to investigate the lipid-lowering properties and mechanisms of action of a new HMG-CoA reductase inhibitor, rosuvastatin, in female ApoE*3-Leiden transgenic mice. Mice received a high fat/cholesterol (HFC) diet containing either rosuvastatin (0 [control], 0.00125%, 0.0025%, or 0.005% [w/w]) or 0.05% (w/w) lovastatin. The highest dose of rosuvastatin reduced plasma cholesterol and triglyceride levels by 39% and 42%, respectively, compared with the HFC control. Lovastatin had no effect on plasma cholesterol and triglyceride levels. In ApoE*3-Leiden mice on a chow diet, rosuvastatin (0.005% [w/w]) decreased plasma cholesterol levels by 35% without having an effect on triglyceride levels. On a chow diet, expression of genes involved in cholesterol biosynthesis and uptake in the liver was increased by rosuvastatin. Further mechanistic studies in HFC-fed mice showed that rosuvastatin treatment resulted in decreased hepatic VLDL-triglyceride and VLDL-apolipoprotein B production. VLDL lipid composition remained unchanged, indicating a reduction in the number of VLDL particles secreted. Lipolytic activity and expression of genes involved in cholesterol and triglyceride synthesis and beta-oxidation of fatty acids in the liver were not affected by rosuvastatin treatment, and hepatic lipid content did not change. However, activity of hepatic diacylglycerol acyltransferase was significantly decreased by 25% after rosuvastatin treatment. Moreover, biliary excretion of cholesterol, phospholipids, and bile acids was increased during treatment. The results indicate that rosuvastatin treatment in ApoE*3-Leiden mice on a HFC diet leads to redistribution of cholesterol and triglycerides in the body, both by reduced hepatic VLDL production and triglyceride synthesis and by enhanced hepatobiliary removal of cholesterol, bile acids, and phospholipids, resulting in substantial reductions in plasma cholesterol and triglyceride levels.

Absence of an atheroprotective effect of the garlic powder printanor in APOE*3-Leiden transgenic mice

Numerous animal studies have reported that garlic can protect against atherosclerosis. However, a comparable number of studies do not support this observation. This contradiction may result from differences in study design, use of different animal models, and use of different garlic formulations and preparations. Here, we investigated the effect of the chemically well-characterized and production-controlled garlic powder printanor on atherosclerosis in the APOE*3-Leiden transgenic mouse, a mouse model well suited for evaluating anti-atherosclerotic properties of drugs and food components under human-like conditions. APOE*3-Leiden mice were fed a Western diet supplemented with either 5 or 50 g kg(-1) printanor. As a reference, the commercially available fermented garlic kyolic was included (1.6 g kg(-1) diet). Treatment with printanor demonstrated reduced body weight, coinciding with increased feces production and fecal fatty acids excretion. Printanor and kyolic treatment did not affect plasma lipids, markers of inflammation (serum amyloid A, serum-soluble intercellular adhesion molecule-1, and blood-leukocytes tumor necrosis factor-alpha (TNFalpha) production) and vascular activation (plasma von Willebrand factor (vWF)). As analyzed after 28 weeks of treatment, printanor and kyolic did not affect atherosclerotic lesion type, area or composition. Under conditions relevant to the human situation, the well-characterized and production-controlled garlic powder printanor does not display hypolipidemic, anti-inflammatory or anti-atherosclerotic properties.

Well-characterized garlic-derived materials are not hypolipidemic in APOE*3-Leiden transgenic mice

Garlic is reported to have beneficial effects on risk factors associated with cardiovascular disease, including normalization of plasma lipid levels. However, numerous studies do not support this beneficial effect of garlic on plasma lipids. This contradiction may result from the use of different garlic-derived materials, experimental designs, and/or animal models. The present study investigated the hypolipidemic effect of garlic-derived materials in APOE*3-Leiden mice, a model well suited for drug and dietary intervention studies of hyperlipidemia. APOE*3-Leiden mice were fed a garlic-derived sulfur-rich compound, either allicin (0.29 g.L drinking water(-1)) or diallyldisulfide (0.27 g.kg diet(-1)), or powdered garlic, of either the kwai (42 g.kg diet(-1)) or morado (42 g.kg diet(-1)) variety. The amounts of garlic-derived materials supplied allowed free intake of allicin or allicin equivalents (diallyldisulfide, kwai, or morado) at 44 mg.kg body wt(-1).d(-1). Mice were fed a nonpurified diet for 4 wk, followed by a Western diet for 8 wk, both supplemented with the garlic-derived materials. These diets had no consistent effect on plasma lipids and did not affect lipoprotein profiles, which are markers for whole-body cholesterol synthesis and intestinal sterol absorption. The current data indicate that the postulated effects of garlic on cardiovascular disease are not caused via modulation of plasma lipid levels.

Increased lipogenesis and resistance of lipoproteins to oxidative modification in two patients with glycogen storage disease type 1a

We describe 2 patients with glycogen storage disease type 1a and severe hyperlipidemia without premature atherosclerosis. Susceptibility of low-density lipoproteins to oxidation was decreased, possibly related to the ~40-fold increase in palmitate synthesis altering lipoprotein saturated fatty acid contents. These findings are potentially relevant for antihyperlipidemic treatment in patients with glycogen storage disease type 1a.