Polyphenol-rich blackcurrant extract exerts hypocholesterolaemic and hypoglycaemic effects in mice fed a diet containing high fat and cholesterol

2015 ◽  
Vol 113 (11) ◽  
pp. 1697-1703 ◽  
Author(s):  
Tyler Benn ◽  
Bohkyung Kim ◽  
Young-Ki Park ◽  
Yue Yang ◽  
Tho X. Pham ◽  
...  
Keyword(s):  
Cholesterol Metabolism ◽  
Regulatory Element ◽  
Liver Steatosis ◽  
Ldl Receptor ◽  
Total Body Weight ◽  
Histological Evaluation ◽  
Mrna Levels ◽  
High Fat ◽  
Metabolic Disturbances ◽  
Increased Risk

Obesity is associated with an increased risk of metabolic abnormalities, such as hyperlipidaemia and hyperglycaemia. We investigated whether polyphenol-rich blackcurrant extract (BCE) can prevent high fat/high cholesterol (HF/HC) diet-induced metabolic disturbances in mice. Male C57BL/6J mice were fed a modified AIN-93M diet containing HF/HC (16 % fat, 0·25 % cholesterol, w/w) or the same diet supplemented with 0·1 % BCE (w/w) for 12 weeks. There were no differences in total body weight and liver weight between groups. Plasma total cholesterol (TC) and glucose levels were significantly lower in BCE group than in controls, while plasma TAG levels were not significantly different. There was a decreasing trend in hepatic TAG levels, and histological evaluation of steatosis grade was markedly lower in the livers of mice fed BCE. Although the mRNA levels of major regulators of hepatic cholesterol metabolism, i.e. 3-hydroxy-3-methyl-glutaryl-CoA reductase (HMGR) and LDL receptor (LDLR), were not significantly altered by BCE supplementation, protein expression of mature sterol-regulatory element-binding protein and LDLR was significantly increased with no change in HMGR protein. The expression of proprotein convertase subtilisin/kexin type 9 that facilitates LDLR protein degradation, as well as one of its transcriptional regulators, i.e. hepatocyte nuclear factor 4α, was significantly decreased in the livers of mice fed BCE. Taken together, BCE supplementation decreased plasma TC and glucose, and inhibited liver steatosis, suggesting that this berry may be consumed to prevent metabolic dysfunctions induced by diets high in fat and cholesterol.

scholarly journals Inactivation of the adrenergic receptor β2 disrupts glucose homeostasis in mice

2014 ◽  
Vol 221 (3) ◽  
pp. 381-390 ◽  
Author(s):  
Gustavo W Fernandes ◽  
Cintia B Ueta ◽  
Tatiane L Fonseca ◽  
Cecilia H A Gouveia ◽  
Carmen L Lancellotti ◽  
...  
Keyword(s):  
Body Weight ◽  
Energy Expenditure ◽  
Glucose Homeostasis ◽  
High Fat Diet ◽  
Liver Steatosis ◽  
Mrna Levels ◽  
High Fat ◽  
Adaptive Thermogenesis ◽  
Brown Adipose ◽  
Similar Body

Three types of beta adrenergic receptors (ARβ1–3) mediate the sympathetic activation of brown adipose tissue (BAT), the key thermogenic site for mice which is also present in adult humans. In this study, we evaluated adaptive thermogenesis and metabolic profile of a mouse withArβ2knockout (ARβ2KO). At room temperature, ARβ2KO mice have normal core temperature and, upon acute cold exposure (4 °C for 4 h), ARβ2KO mice accelerate energy expenditure normally and attempt to maintain body temperature. ARβ2KO mice also exhibited normal interscapular BAT thermal profiles during a 30-min infusion of norepinephrine or dobutamine, possibly due to marked elevation of interscapular BAT (iBAT) and ofArβ1, andArβ3mRNA levels. In addition, ARβ2KO mice exhibit similar body weight, adiposity, fasting plasma glucose, cholesterol, and triglycerides when compared with WT controls, but exhibit marked fasting hyperinsulinemia and elevation in hepaticPepck(Pck1) mRNA levels. The animals were fed a high-fat diet (40% fat) for 6 weeks, ARβ2KO mice doubled their caloric intake, accelerated energy expenditure, and inducedUcp1expression in a manner similar to WT controls, exhibiting a similar body weight gain and increase in the size of white adipocytes to the WT controls. However, ARβ2KO mice maintain fasting hyperglycemia as compared with WT controls despite very elevated insulin levels, but similar degrees of liver steatosis and hyperlipidemia. In conclusion, inactivation of the ARβ2KO pathway preserves cold- and diet-induced adaptive thermogenesis but disrupts glucose homeostasis possibly by accelerating hepatic glucose production and insulin secretion. Feeding on a high-fat diet worsens the metabolic imbalance, with significant fasting hyperglycemia but similar liver structure and lipid profile to the WT controls.

Abstract 655: Rac2 is a Key Modulator of IL-1β -dependent Atherosclerotic Plaque Calcification

2016 ◽  
Vol 36 (suppl_1) ◽  
Author(s):  
Nicolle Ceneri ◽  
Lina Zhao ◽  
Bryan D Young ◽  
Abigail L Healy ◽  
Suleyman Coskun ◽  
...  
Keyword(s):  
Atherosclerotic Plaque ◽  
High Fat Diet ◽  
Cardiovascular Events ◽  
Stable Coronary Artery Disease ◽  
Plaque Burden ◽  
Mrna Levels ◽  
Dependent Manner ◽  
High Fat ◽  
Increased Risk ◽  
Calcified Plaque

The calcium composition of atherosclerotic plaque has predictive value for increased risk of cardiovascular events. Inflammation is associated with atherosclerotic calcification, but the immune signaling that regulates calcium mineralization in plaque is minimally understood. The hematopoietic Rac family member, Rac2, modulates the activation of immune cells and has potential to influence plaque osteogenesis. Both aortic plaque from ApoE -/- mice fed a high fat diet and coronary plaque from patients revealed increased Rac1:Rac2 expression ratios, driven by dynamic Rac2 expression, to be associated with calcified plaque. On high fat diet, Rac2 -/- ApoE -/- mice demonstrated comparable serum cholesterol and plaque burden relative to ApoE -/- mice, but histology identified differences in plaque structure and cellularity. MicroCT and calcium-targeted imaging identified increased atherosclerotic calcification, which was associated with elevated expression of osteogenic transcription factors and was dependent on the hematopoietic compartment. Calcified plaque expressed higher IL-1β mRNA levels, and serum revealed increased IL-1β protein concentrations. Rac2 -/- ApoE -/- macrophages demonstrated increased activation of Rac1 and consequent Rac1-dependent IL-1β secretion. Downstream of Rac1, NF-κB and reactive oxygen species (ROS) signaling drove IL-1β production by increasing IL-1β mRNA expression and caspase1 activation. Cultured mouse aorta smooth muscle cells mineralized calcium in an IL-1β dose-dependent manner, and the enhanced atherosclerotic calcification in vivo was inhibited by IL-1 receptor antagonist, confirming a cause-and-effect relationship. In patients with stable coronary artery disease, high coronary calcium burden was associated with increased serum IL-1β, and patients with combined elevations in calcium and IL-1β had more events driven by higher mortality, reinforcing the relevance of this inflammatory calcification signaling axis to human disease. Therapeutic targeting of IL-1β expression through the balance of Rac activation has potential to impact patient care by modulating atherosclerotic calcification and consequent cardiovascular events.

scholarly journals Vascular Disease Is Associated With the Expression of Genes for Intestinal Cholesterol Transport and Metabolism

2016 ◽  
Vol 102 (1) ◽  
pp. 326-335
Author(s):  
William M. Widdowson ◽  
Anne McGowan ◽  
James Phelan ◽  
Gerard Boran ◽  
John Reynolds ◽  
...  
Keyword(s):  
Endothelial Function ◽  
Vascular Disease ◽  
Cholesterol Metabolism ◽  
Human Subjects ◽  
Regulatory Element ◽  
Area Under The Curve ◽  
Mrna Levels ◽  
Cardiovascular Risks ◽  
Postprandial Lipid Metabolism ◽  
Postprandial Triglyceride

Abstract Context: Intestinal cholesterol metabolism is important in influencing postprandial lipoprotein concentrations, and might be important in the development of vascular disease. Objective: This study evaluated associations between expression of intestinal cholesterol metabolism genes, postprandial lipid metabolism, and endothelial function/early vascular disease in human subjects. Design/Patients: One hundred patients undergoing routine oesophago-gastro-duodenoscopy were recruited. mRNA levels of Nieman-Pick C1-like 1 protein (NPC1L1), ABC-G5, ABC-G8, ABC-A1, microsomal tissue transport protein (MTTP), and sterol-regulatory element-binding protein (SREBP)-2 were measured in duodenal biopsies using quantitative reverse transcription polymerase chain reaction. Postprandially, serum lipid and glycemic profiles were measured, endothelial function was assessed using fasting, and postprandial flow-mediated dilatation (FMD) and carotid intima-media thickness (IMT). Subjects were divided into those above and below the median value of relative expression of each gene, and results were compared between the groups. Results: There were no between-group differences in demographic variables or classical cardiovascular risks. For all genes, the postprandial triglyceride incremental area under the curve was greater (P < 0.05) in the group with greater expression. Postprandial apolipoprotein B48 (ApoB48) levels were greater (P < 0.05) in groups with greater expression of NPC1L1, ABC-G8, and SREBP-2. For all genes, postprandial but not fasting FMD was lower (P < 0.01) in the group with greater expression. Triglyceride and ApoB48 levels correlated significantly with postprandial FMD. Carotid artery IMT was greater (P < 0.05) in groups with greater expression of MTTP, ABC-A1, and SREBP-2. Conclusion: Intestinal cholesterol metabolism gene expression is significantly associated with postprandial increment in triglycerides, intestinal ApoB48, and reduced postprandial FMD. Some genes were also associated with increased IMT. These findings suggest a role of intestinal cholesterol metabolism in development of early vascular disease.

scholarly journals n-3 PUFA prevent metabolic disturbances associated with obesity and improve endothelial function in golden Syrian hamsters fed with a high-fat diet

2011 ◽  
Vol 107 (9) ◽  
pp. 1305-1315 ◽  
Author(s):  
Fatima Kasbi Chadli ◽  
Agnès Andre ◽  
Xavier Prieur ◽  
Gervaise Loirand ◽  
Anne Meynier ◽  
...  
Keyword(s):  
Endothelial Function ◽  
Glucose Intolerance ◽  
High Fat Diet ◽  
Regulatory Element ◽  
Control Diet ◽  
Scavenger Receptor ◽  
Hdl Cholesterol ◽  
Control Group ◽  
High Fat ◽  
Metabolic Disturbances

Glucose intolerance and dyslipidaemia are independent risk factors for endothelium dysfunction and CVD. The aim of the present study was to analyse the preventive effect of n-3 PUFA (EPA and DHA) on lipid and carbohydrate disturbances and endothelial dysfunction. Three groups of adult hamsters were studied for 20 weeks: (1) control diet (Control); (2) high-fat diet (HF); (3) high-fat diet enriched with n-3 PUFA (HFn-3) groups. The increase in body weight and fat mass in the HF compared to the Control group (P < 0·05) was not found in the HFn-3 group. Muscle TAG content was similar in the Control and HF groups, but significantly lower in the HFn-3 group (P = 0·008). Glucose tolerance was impaired in the HF compared to the Control group, but this impairment was prevented by n-3 PUFA in the HFn-3 group (P < 0·001). Plasma TAG and cholesterol were higher in the HF group compared to the Control group (P < 0·001), but lower in the HFn-3 group compared to the HF group (P < 0·001). HDL-cholesterol was lower in the HFn-3 group compared to the Control and HF groups (P < 0·0005). Hepatic secretion of TAG was lower in the HFn-3 group compared to the HF group (P < 0·005), but did not differ from the Control group. Hepatic gene expression of sterol regulatory element-binding protein-1c, diacylglycerol O-acyltransferase 2 and stearyl CoA desaturase 1 was lower in the HFn-3 group, whereas carnitine palmitoyl transferase 1 and scavenger receptor class B type 1 expression was higher (P < 0·05). In adipocytes and adipose macrophages, PPARγ and TNFα expression was higher in the HF and HFn-3 groups compared to the Control group. Endothelium relaxation was higher in the HFn-3 (P < 0·001) than in the HF and Control groups, and was correlated with glucose intolerance (P = 0·03) and cholesterol (P = 0·0003). In conclusion, n-3 PUFA prevent some metabolic disturbances induced by high-fat diet and improve endothelial function in hamsters.

scholarly journals Identification of liver CYP51 as a gene responsive to circulating cholesterol in a hamster model

2016 ◽  
Vol 5 ◽  
Author(s):  
Haiqiu Huang ◽  
Zhuohong Xie ◽  
Wallace Yokoyama ◽  
Liangli Yu ◽  
Thomas T. Y. Wang
Keyword(s):  
High Fat Diet ◽  
Cholesterol Metabolism ◽  
Ldl Receptor ◽  
High Fat ◽  
Hamster Model ◽  
Hmg Coa Reductase ◽  
Cholesterol Levels ◽  
Reductase Mrna ◽  
Coa Reductase ◽  
The Relationship

AbstractHypercholesterolaemia is a risk factor for CVD, which is a leading cause of death in industrialised societies. The biosynthetic pathways for cholesterol metabolism are well understood; however, the regulation of circulating cholesterol by diet is still not fully elucidated. The present study aimed to gain more comprehensive understanding of the relationship between circulating cholesterol levels and molecular effects in target tissues using the hamster model. Male golden Syrian hamsters were fed with chow or diets containing 36 % energy from fat with or without 1 % cholesteyramine (CA) as a modulator of circulating cholesterol levels for 35 d. It was revealed that the expression of lanosterol 14α-demethylase (CYP51) instead of 3-hydroxy-3-methyl-glutaryl (HMG)-CoA reductase mRNA expression was responsive to circulating cholesterol in hamsters fed hypercholesterolaemic diets. The high-fat diet increased circulating cholesterol and down-regulated CYP51, but not HMG-CoA reductase. The CA diet decreased cholesterol and increased CYP51 expression, but HMG-CoA reductase expression was not affected. The high-fat diet and CA diet altered the expression level of cholesterol, bile acids and lipid metabolism-associated genes (LDL receptor, cholesterol 7α-hydroxylase (CYP7A1), liver X receptor (LXR) α, and ATP-binding cassette subfamily G member 5/8 (ABCG5/8)) in the liver, which were significantly correlated with circulating cholesterol levels. Correlation analysis also showed that circulating cholesterol levels were regulated by LXR/retinoid X receptor and PPAR pathways in the liver. Using the hamster model, the present study provided additional molecular insights into the influence of circulating cholesterol on hepatic cholesterol metabolism pathways during hypercholesterolaemia.

scholarly journals Young APPKI NL-G-F/NL-G-F mice display high-fat diet-induced metabolic disturbances and specific disorders associated with brain energy homeostasis.

2021 ◽  
Author(s):  
Wei Wang ◽  
Daisuke Tanokashira ◽  
Megumi Maruyama ◽  
Chiemi Kuroiwa ◽  
Takashi Saito ◽  
...  
Keyword(s):  
Mouse Models ◽  
High Fat Diet ◽  
Early Life ◽  
Energy Homeostasis ◽  
Normal Diet ◽  
Aging Effects ◽  
High Fat ◽  
Metabolic Disturbances ◽  
Increased Risk ◽  
Brain Energy

Aim: Type 2 diabetes mellitus (T2DM) is an increased risk factor for Alzheimer's disease (AD); however, the relationship between the two conditions is controversial. High-fat diet (HFD) causes cognitive impairment with/without Aβ accumulation in middle-aged or aged transgenic (Tg) and knock-in (KI) AD mouse models, except for metabolic disorders, which commonly occur in all mice types. Alternatively, whether HFD in early life impacts energy metabolism and neurological phenotypes in young AD mouse models remains unknown. In the present study, we examined the effects of HFD on young APPKI NL-G-F/NL-G-F mice, one of the novel knock-in (KI)-AD mouse models. Methods: The mice were categorized by diet into two experimental groups, normal diet (ND) and HFD. Four-week-old WT and APPKI NL-G-F/NL-G-F mice were fed ND or HFD for nine weeks. Both types of mice on ND and HFD were examined during young adulthood. Results: HFD causes T2DM-related metabolic disturbances in young WT and APPKI NL-G-F/NL-G-F mice and specific impairment of brain energy homeostasis only in young APPKI NL-G-F/NL-G-F mice. However, HFD-induced metabolic dysfunctions had no impact on behaviors, Aβ levels, and specific IRS1 modifications in both young APPKI NL-G-F/NL-G-F mice and young WT mice. Conclusion: HFD in early life is effective in causing metabolic disturbances in young WT and APPKI NL-G-F/NL-G-F mice but is ineffective in inducing neurological disorders in young mice, which suggests that the aging effects along with long-term HFD cause neurological alterations.

Resistance to high-fat diet-induced obesity and altered expression of adipose-specific genes in HSL-deficient mice

2003 ◽  
Vol 285 (6) ◽  
pp. E1182-E1195 ◽  
Author(s):  
Kenji Harada ◽  
Wen-Jun Shen ◽  
Shailja Patel ◽  
Vanita Natu ◽  
Jining Wang ◽  
...  
Keyword(s):  
Adipose Tissue ◽  
Insulin Receptor ◽  
Binding Protein ◽  
Regulatory Element ◽  
Mrna Levels ◽  
High Fat ◽  
Diet Induced Obesity ◽  
Element Binding Protein ◽  
Sterol Regulatory Element ◽  
Adipose Differentiation

To elucidate the role of hormone-sensitive lipase (HSL) in diet-induced obesity, HSL-deficient ( HSL– /–) and wild-type mice were fed normal chow or high-fat diets. HSL– /– mice were resistant to diet-induced obesity showing higher core body temperatures. Weight and triacylglycerol contents were decreased in white adipose tissue (WAT) but increased in both brown adipose tissue (BAT) and liver of HSL– /– mice. Serum insulin levels in the fed state and tumor necrosis factor-α mRNA levels in adipose tissues were higher, whereas serum levels of adipocyte complement-related protein of 30 kDa (ACRP30)/adiponectin and leptin, as well as mRNA levels of ACRP30/adiponectin, leptin, resistin, and adipsin in WAT, were lower in HSL– /– mice than in controls. Expression of transcription factors associated with adipogenesis (peroxisome proliferator-activated receptor-γ, CAAT/enhancer-binding protein-α) and lipogenesis (carbohydrate response element-binding protein, adipocyte determination- and differentiation-dependent factor-1/sterol regulatory element-binding protein-1c), as well as of adipose differentiation markers (adipocyte lipid-binding protein, perilipin, lipoprotein lipase), lipogenic enzymes (glycerol-3-phosphate acyltransferase, acyl-CoA:diacylglycerol acyltransferase-1 and -2, fatty acid synthase, ATP citrate lyase) and insulin signaling proteins (insulin receptor, insulin receptor substrate-1, GLUT4), was suppressed in WAT but not in BAT of HSL– /– mice. In contrast, expression of genes associated with cholesterol metabolism (sterol-regulatory element-binding protein-2, 3-hydroxy-3-methylglutaryl-CoA reductase, acyl-CoA:cholesterol acyltransferase-1) and thermogenesis (uncoupling protein-2) was upregulated in both WAT and BAT of HSL– /– mice. Our results suggest that impaired lipolysis in HSL deficiency affects lipid metabolism through alterations of adipose differentiation and adipose-derived hormone levels.

scholarly journals Soya phytoestrogens, genistein and daidzein, decrease apolipoprotein B secretion from HepG2 cells through multiple mechanisms

2002 ◽  
Vol 366 (2) ◽  
pp. 531-539 ◽  
Author(s):  
Nica M. BORRADAILE ◽  
Linda E. de DREU ◽  
Lisa J. WILCOX ◽  
Jane Y. EDWARDS ◽  
Murray W HUFF
Keyword(s):  
Hepg2 Cells ◽  
Cholesterol Synthesis ◽  
Cholesterol Metabolism ◽  
Plasma Cholesterol ◽  
Ldl Receptor ◽  
Density Lipoprotein ◽  
Mrna Levels ◽  
Apo B ◽  
Cellular Cholesterol ◽  
Apob Secretion

Diets containing the soya-derived phytoestrogens, genistein and daidzein, decrease plasma cholesterol in humans and experimental animals. The mechanisms responsible for the hypocholesterolaemic effects of these isoflavones are unknown. The present study was conducted to determine if genistein and daidzein regulate hepatocyte cholesterol metabolism and apolipoprotein (apo) B secretion in cultured human hepatoma (HepG2) cells. ApoB secretion was decreased dose-dependently by up to 63% and 71% by genistein and daidzein (100μM; P<0.0001) respectively. In contrast, no effect on apoAI secretion was observed. Cellular cholesterol synthesis was inhibited 41% by genistein (100μM; P<0.005) and 18% by daidzein (100μM; P<0.05), which was associated with significant increases in 3-hydroxy-3-methylglutaryl-CoA reductase mRNA. Cellular cholesterol esterification was decreased 56% by genistein (100μM; P<0.04) and 29% by daidzein (100μM; P<0.04); however, mRNA levels for acyl-CoA:cholesterol acyltransferase (ACAT) 1 and ACAT2 were unaffected. At 100μM, both isoflavones equally inhibited the activities of both forms of ACAT in cells transfected with either ACAT1 or ACAT2. Genistein (100μM) and daidzein (100μM) significantly decreased the activity of microsomal triacylglycerol transfer protein (MTP) by 30% and 24% respectively, and significantly decreased MTP mRNA levels by 35% and 55%. Both isoflavones increased low-density lipoprotein (LDL)-receptor mRNA levels by 3- to 6-fold (100μM; P<0.03) and significantly increased the binding, uptake and degradation of 125I-labelled LDL, suggesting that enhanced reuptake of newly secreted apoB-containing lipoproteins contributed to the net decrease in apoB secretion. These results indicate that genistein and daidzein inhibit hepatocyte apoB secretion through several mechanisms, including inhibition of cholesterol synthesis and esterification, inhibition of MTP activity and expression and increased expression of the LDL-receptor.

scholarly journals Effects of periconceptional maternal alcohol intake and a postnatal high-fat diet on obesity and liver disease in male and female rat offspring

2018 ◽  
Vol 315 (4) ◽  
pp. E694-E704 ◽  
Author(s):  
Emelie M. Gårdebjer ◽  
James S. M. Cuffe ◽  
Leigh C. Ward ◽  
Sarah Steane ◽  
Stephen T. Anderson ◽  
...  
Keyword(s):  
Fat Mass ◽  
High Fat Diet ◽  
Liver Steatosis ◽  
Alcohol Exposure ◽  
Mrna Levels ◽  
Female Rat ◽  
Sprague Dawley ◽  
High Fat ◽  
Maternal Alcohol ◽  
Tnf Α

The effects of maternal alcohol consumption around the time of conception on offspring are largely unknown and difficult to determine in a human population. This study utilized a rodent model to examine if periconceptional alcohol (PC:EtOH) consumption, alone or in combination with a postnatal high-fat diet (HFD), resulted in obesity and liver dysfunction. Sprague-Dawley rats were fed a control or an ethanol-containing [12.5% (vol/vol) EtOH] liquid diet from 4 days before mating until 4 days of gestation ( n = 12/group). A subset of offspring was fed a HFD between 3 and 8 mo of age. In males, PC:EtOH and HFD increased total body fat mass ( PPC:EtOH < 0.05, PHFD < 0.0001); in females, only HFD increased fat mass ( PHFD < 0.0001). PC:EtOH increased microvesicular liver steatosis in male, but not female, offspring. Plasma triglycerides, HDL, and cholesterol were increased in PC:EtOH-exposed males ( PPC:EtOH < 0.05), and LDL, cholesterol, and leptin (Lep) were increased in PC:EtOH-exposed females ( PPC:EtOH < 0.05). mRNA levels of Tnf-α and Lep in visceral adipose tissue were increased by PC:EtOH in both sexes ( PPC:EtOH < 0.05), and Il-6 mRNA was increased in males ( PPC:EtOH < 0.05). These findings were associated with reduced expression of microRNA-26a, a known regulator of IL-6 and TNF-α. Alcohol exposure around conception increases obesity risk, alters plasma lipid and leptin profiles, and induces liver steatosis in a sex-specific manner. These programmed phenotypes were similar to those caused by a postnatal HFD, particularly in male offspring. These results have implications for the health of offspring whose mothers consumed alcohol around the time of conception.

scholarly journals Two Weeks of Western Diet Disrupts Liver Molecular Markers of Cholesterol Metabolism in Rats

2020 ◽  
Author(s):  
Roxane Saint-Amand ◽  
Emilienne T. Ngo Sock ◽  
Samantha Quinn ◽  
Jean-Marc Lavoie ◽  
David H. St-Pierre
Keyword(s):  
De Novo ◽  
Cholesterol Metabolism ◽  
Plasma Cholesterol ◽  
Ldl Receptor ◽  
Mrna Levels ◽  
Fat Pad ◽  
Cholesterol Uptake ◽  
Cholesterol Levels ◽  
Gene Coding ◽  
Main Regulator

Abstract Background The present study was designed to test the hypothesis that excessive fat accumulations impair cholesterol metabolism mainly through alterations in the LDL-receptor (LDL-R) pathway in liver. Method: Rats were either submitted to standard (SD), high fat (HFD; 60% kcal) or western (WD; 40% fat + 35% sucrose (17.5% fructose)) diets for 2 or 6 weeks. Results Weight gain (~ 40 g) was observed only following 6 weeks of the obesogenic diets (P < 0.01). Compared to the 2-week treatment, obesogenic diets tripled fat pad weight (~ 20 vs 7 g) after 6 weeks. Hepatic triglyceride (TG) levels were greater in response to both the WD and HFD compared to the SD (P < 0.01) at 2 and 6 weeks and their concentrations were greater (P < 0.05) in WD than HFD at 2 weeks. Plasma cholesterol levels were higher (P < 0.05) in animals submitted to WD. After 2 and 6 weeks, liver expression of LDL-R, PCSKk9 and SREBP2, involved in LDL-cholesterol uptake, was lower in animals submitted to WD than in others treated with HFD or SD (P < 0.01). Similarly, LRP1 and ACAT2 mRNA levels were lower (P < 0.01) among WD compared to SD-fed rats. Expression of the gene coding the main regulator of endogenous cholesterol synthesis, HMGCoAR was reduced in response to WD compared to SD and HFD at 2 (P < 0.001) and 6 (P < 0.05) weeks. Being enriched in fructose, the WD strongly promoted the expression of ChREBP and ACC, two key regulators of de novo lipogenesis. Conclusion These results show that the WD promptly increased TG levels in the liver by potentiating dietary fat storage and de novo lipogenesis. This impaired the pathway of hepatic cholesterol uptake via the LDL-R axis, promoting a rapid increase in plasma cholesterol levels.

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