High-fat And High-cholesterol Diet Research Articles

L-aspartate ameliorates diet-induced obesity by increasing adipocyte energy expenditure.

Obesity always leads to profound perturbation of metabolome. Metabolome studies enrich the knowledge on associations between endogenous metabolites and obesity, potentially providing innovative strategies for the development of novel anti-obesity pharmacotherapy. This study aims to identify an endogenous metabolite that regulates energy expenditure and to explore its application for obesity treatment. C57BL/6 mice were fed with a high-fat and high-cholesterol (HFC) diet, comprising 60% fat and 1.2% cholesterol, for 12 weeks to induce obesity. Significant metabolites were identified in the livers of both health and obese mice through comparative hepatic metabolomics analysis. Correlation between serum or adipose L-aspartate level and body weight in obese mice, as well as human body mass index (BMI), was evaluated. In addition, saline or 200 mg/kg L-aspartate was orally administrated to HFC diet mice and HFC diet-induced obese mice for 6-7 weeks. Body weight, adipose tissue weight, glucose tolerance and liver damage were assessed to evaluate the effect on obesity prevention and treatment. Comprehensive lab animal monitoring system (CLAMS) and seahorse assay were employed to investigate the regulatory effect of L-aspartate on energy metabolism in vivo and in vitro, respectively. 3T3-L1 preadipocytes and murine white adipose tissue (WAT) were utilized to examine the impact of L-aspartate on adipocyte adipogenesis and lipogenesis and cellular signalling pathway in vitro and in vivo. L-aspartate, an approved drug for liver injury and chronic fatigue, was identified as an endogenous inducer of energy expenditure. Serum or adipose L-aspartate levels were found to be negatively correlated with the severity of obesity in both humans and mice. Administration of L-aspartate to HFC diet mice led to a significant reduction in body weight, with decreases of 14.5% in HFC diet mice and 8.5% in HFC diet-induced obese mice, respectively. In addition, the treatment improved related metabolic syndrome (Figure 2 and Figure S3). These therapeutics were associated with enhancements in whole-body energy expenditure and suppression of adipocyte adipogenesis along with activation of Adenosine 5'-monophosphate-activated protein kinase (AMPK) signalling pathway. L-aspartate may serve as a novel endogenous inducer of energy expenditure and suppressor of adipogenesis and lipogenesis along with activation of AMPK, thereby offering a promising therapeutic strategy for obesity prevention and treatment.

Effect of rapamycin on hepatic metabolomics of non-alcoholic fatty liver rats based on non-targeted platform

Rapamycin (Rapa) is an inhibitor of mTOR complex, and its therapeutic effect on liver function was examined in non-alcoholic fatty liver disease (NAFLD) rats here. And the possible mechanism of Rapa in NAFLD was preliminarily elucidated based on the non-targeted metabolomics analysis. Adult male SD rats were fed with a high-fat and high-cholesterol diet (HFD) to establish NAFLD model. For Rapa group, 0.8 mg/(kg.d) Rapa was given to the HFD rats. Ultra-performance liquid chromatography and Q-Tof-mass spectrometry (UPLC and Q-TOF/MS) analysis were applied for the identification of metabolites in the serum of rats, which were annotated using Kyoto Encyclopedia of Genes and Genomes (KEGG). NAFLD rats presented with disturbed liver function, lipid metabolism and oxidative stress, but Rapa exerted a mitigating influence on the disorders. The metabolite profile data identified 579 metabolites that varied remarkably between the Rapa and HFD groups, with the main classes of amino acids and peptides, benzene, lipids and fatty acids. The differential metabolites were mainly involved in biosynthesis of cofactors, bile secretion, and glycerophospholipid metabolism were mainly enriched. In conclusion, Rapa has a potential protective effect against HFD-induced NAFLD, its hepatoprotective effect may achieved through mediating bile secretion and glycerophospholipid metabolism.

Lactobacillus buchneri ameliorates obesity-related disorders induced by high-fat and high-cholesterol diet in mice

Diet-induced obesity is a serious social issue which can cause various metabolic diseases, such as lipid metabolism disorders, chronic inflammation, and liver steatosis. Recently, probiotics have shown promise in preventing and alleviating obesity and related metabolic syndromes. Here, we investigated the effects of Lactobacillus buchneri intervention on obesity-related disorders in mice fed a high-fat and high-cholesterol diet (HFHCD). The administration of L. buchneri to the HFHCD-induced mice reduced body weight gain, fat accumulation, serum triglycerides, and total cholesterol levels. Additionally, L. buchneri treatment restored triglycerides, total cholesterol, total bile acid, aspartate aminotransferase, and alanine aminotransferase to normal levels in the liver, and ameliorated hepatic steatosis in the HFHCD-induced mice. Consistently, qPCR analysis demonstrated that L. buchneri treatment downregulated the expression of lipogenesis Dgat1 and inflammatory IL-1β in the liver. Finally, 16S rRNA gene sequencing revealed that L. buchneri treatment had a mild impact on the gut microbiota community structure, indicating that the amelioration of obesity-related disorders may not be solely attributed to gut microbiota modulation. In conclusion, these findings provide evidence that L. buchneri can be considered a probiotic to ameliorate obesity-related disorders.

Remodeling Intestinal Microbiota Alleviates Severe Combined Hyperlipidemia-Induced Nonalcoholic Steatohepatitis and Atherosclerosis in LDLR-/- Hamsters.

Combined hyperlipidemia (CHL) manifests as elevated cholesterol and triglycerides, associated with fatty liver and cardiovascular diseases. Emerging evidence underscores the crucial role of the intestinal microbiota in metabolic disorders. However, the potential therapeutic viability of remodeling the intestinal microbiota in CHL remains uncertain. In this study, CHL was induced in low-density lipoprotein receptor-deficient (LDLR-/-) hamsters through an 8-week high-fat and high-cholesterol (HFHC) diet or a 4-month high-cholesterol (HC) diet. Placebo or antibiotics were administered through separate or cohousing approaches. Analysis through 16S rDNA sequencing revealed that intermittent antibiotic treatment and the cohousing approach effectively modulated the gut microbiota community without impacting its overall abundance in LDLR-/- hamsters exhibiting severe CHL. Antibiotic treatment mitigated HFHC diet-induced obesity, hyperglycemia, and hyperlipidemia, enhancing thermogenesis and alleviating nonalcoholic steatohepatitis (NASH), concurrently reducing atherosclerotic lesions in LDLR-/- hamsters. Metabolomic analysis revealed a favorable liver lipid metabolism profile. Increased levels of microbiota-derived metabolites, notably butyrate and glycylglycine, also ameliorated NASH and atherosclerosis in HFHC diet-fed LDLR-/- hamsters. Notably, antibiotics, butyrate, and glycylglycine treatment exhibited protective effects in LDLR-/- hamsters on an HC diet, aligning with outcomes observed in the HFHC diet scenario. Our findings highlight the efficacy of remodeling gut microbiota through antibiotic treatment and cohousing in improving obesity, NASH, and atherosclerosis associated with refractory CHL. Increased levels of beneficial microbiota-derived metabolites suggest a potential avenue for microbiome-mediated therapies in addressing CHL-associated diseases.

Chronic Real-Ambient PM2.5 Exposure Exacerbates Cardiovascular Risk via Amplifying Liver Injury in Mice Fed with a High-Fat and High-Cholesterol Diet.

Epidemiology has associated fine particulate matter (PM2.5) exposure with an increased cardiovascular risk. However, the underlying mechanism, particularly from the liver perspective, remains unclear. Here, the influence of chronic PM2.5 exposure on cardiovascular risk in mice fed a high-fat and high-cholesterol diet (HFCD) was studied by using a real-world PM2.5 exposure system. Results showed that PM2.5 exposure elevated the serum levels of nonhigh-density lipoprotein cholesterol (non-HDL-C) and oxidized low-density lipoprotein (oxLDL) in HFCD-fed mice, demonstrating increased cardiovascular risk. To investigate the molecular mechanism, lipidomics and metabolomics analyses were conducted and revealed that PM2.5 exposure enhanced lipid accumulation and disturbed purine metabolism and glutathione metabolism in the liver of HFCD-fed mice, contributing to the elevated non-HDL-C levels and intensified oxidative stress. Moreover, PM2.5 exposure increased total cholesterol levels by upregulating Hmgcr expression and downregulating Cyp7a1 expression in the livers of HFCD-fed mice. The HDL-C level was reduced by inhibiting the hepatic Abca1 and Abcg1 expression and decreasing the levels of ApoA-I and LCAT. Additionally, the PM2.5-induced pro-oxidative environment impeded the oxLDL clearance and further triggered inflammation, in turn exacerbating oxidative stress and oxLDL production. This study demonstrated a synergy of PM2.5 and HFCD on cardiovascular risk and illuminated the molecular mechanism in PM2.5-susceptible populations.

Uric Acid Elevation by Fructose Overload Exacerbates Nash and Atherosclerosis via Oxidative Stress

Background: Nonalcoholic steatohepatitis (NASH) is well associated with an increased risk of cardiovascular disease (CVD), regardless of risk factors for metabolic syndrome. However, intermediary factors between NASH and CVD remain unknown. In recent years, hyperuricemia has been associated not only with gout but also with several other organ diseases, such as hypertension, chronic renal failure, and metabolic syndrome. In addition, hyperuricemia was shown to frequently occur in patients with NASH and could be a risk factor for CVD. Furthermore, serum uric acid (UA) levels have been linked with fructose intake. Objectives: We hypothesized that fructose loading elevates UA levels and exacerbates NASH and atherosclerosis via oxidative stress. Methods: Stroke-prone spontaneously hypertensive rats (SHRSP5/Dmcr), between 14 to 24 weeks of age, were divided into two groups and fed a high-fat and high-cholesterol (HFC) diet. In addition to the HFC diet, the fructose group was subjected to 10% fructose loading. The oral glucose tolerance test (OGTT) and insulin tolerance test (ITT) were performed at 25-week-old, followed by blood sampling, animal sacrifice, endothelial function test, blood biochemistry, histopathological staining, xanthine oxidase activity test, and genetic analysis performed at 26-week-old. Results: Fructose loading increased UA and oxidative stress levels. In addition, fructose loading induced insulin resistance. The fructose group exhibited aggravated hepatic fibrosis and lipid deposition, as well as enhanced lipid accumulation in the mesenteric arteries. Conclusion: In the SHRSP5/Dmcr rat model, elevated UA levels were a risk factor for the exacerbation of NASH and atherosclerosis via oxidative stress.

Study on the mechanism of vitamin E alleviating non-alcoholic fatty liver function based on non-targeted metabolomics analysis in rats.

Non-alcoholic fatty liver disease (NAFLD) is a hepatic manifestation of metabolic syndrome. Vitamin E (VE) has antioxidant properties and can mediate lipid metabolism. Non-targeted metabolomics technology was employed to uncover comprehensively the metabolome of VE in NAFLD rats. NAFLD model was created with a high-fat and high-cholesterol diet (HFD) in rats. NAFLD rats in the VE group were given 75mg/(kg day) VE. The metabolites in the serum of rats were identified via UPLC and Q-TOF/MS analysis. KEGG was applied for the pathway enrichment. VE improved the liver function, lipid metabolism, and oxidative stress in NAFLD rats induced by HFD. Based on the metabolite profile data, 132 differential metabolites were identified between VE group and the HFD group, mainly including pyridoxamine, betaine, and bretylium. According to the KEGG results, biosynthesis of cofactors was a key metabolic pathway of VE in NAFLD rats. VE can alleviate NAFLD induced by HFD, and the underlying mechanism is associated with the biosynthesis of cofactors, mainly including pyridoxine and betaine.

N-3 polyunsaturated fatty acids in phospholipid or triacylglycerol form attenuate nonalcoholic fatty liver disease via mediating cannabinoid receptor 1/adiponectin/ceramide pathway

n-3 polyunsaturated fatty acids (PUFA) have shown to exert beneficial effects in the treatment of nonalcoholic fatty liver disease (NAFLD). Supplements of n-3 PUFA occur in either phospholipid or triacylglycerol form. The present study aimed to compare whether the different n-3 PUFA of marine-origin, namely krill oil, DHA/EPA-phospholipid (PL), and EPA/DHA-triacylglycerol (TAG) forms had differential abilities to ameliorate NAFLD. The NAFLD model was established in mice fed a high-fat and high-cholesterol diet (HFD). The mice showed evidence of weight gain, dyslipidemia, insulin resistance and hepatic steatosis after 9 weeks of HFD, while the three forms of the n-3 PUFA reduced hepatic TAG accumulation, fatty liver and improved insulin instance, and hepatic biomarkers after 9 weeks of intervention. Of these, krill oil intervention significantly reduced adipocyte hypertrophy and hepatic steatosis in comparison with DHA/EPA-PL and EPA/DHA-TAG groups. Importantly, only krill oil intervention significantly reduced serum alanine transaminase, aspartate transaminase concentrations and low-density lipoprotein-cholesterol, compared with the HFD group. Supplemental n-3 PUFA lowered circulating anandamide (AEA) and 2-arachidonoylglycerol (2-AG) concentrations, compared with the HFD group, which was associated with down-regulating CB1 and upregulating adiponectin expressions in adipose tissue. Besides, targeted lipidomic analyses indicated that the increased adiponectin levels were accompanied by reductions in hepatic ceramide levels. The reduced ceramide levels were associated with inhibiting lipid synthesis and increasing fatty acid β-oxidation, finally inhibiting TAG accumulation in the liver. Through mediating CB1/adiponectin/ceramide pathway, the present study suggested that administration of krill oil had superior health effects in the therapy of NAFLD in comparison with DHA/EPA-PL and EPA/DHA-TAG.

Si-Ni-San Reduces Hepatic Lipid Deposition in Rats with Metabolic Associated Fatty Liver Disease by AMPK/SIRT1 Pathway.

Metabolic associated fatty liver disease (MAFLD) is a chronic disease characterized by excessive lipid deposition in the liver without alcohol or other clear liver-damaging factors. AMP-activated protein kinase (AMPK)/silencing information regulator (SIRT)1 signaling pathway plays an important role in MAFLD development. Si-Ni-San (SNS), a traditional Chinese medicine, has shown reducing hepatic lipid deposition in MAFLD rats, however, the underlying mechanisms of SNS are barely understood. The aim of this research was to investigate the mechanisms of SNS in reducing hepatic lipid deposition in MAFLD rats by regulating AMPK/SIRT1 signaling pathways. The components of SNS were determined by high performance liquid chromatography with mass spectrometry (HPLC-MS) analysis. MAFLD rats were induced by high-fat and high-cholesterol diet (HFHCD), and treated by SNS. SNS-containing serum and Compound C (AMPK inhibitor) were used to treat palmitic acid (PA)-induced HepG2 cells. To elucidate the potential mechanism, lipid synthesis-related proteins (SREBP-1c and FAS), fatty acid oxidation (PPARα and CPT-1), and AMPK/SIRT1 signaling pathway (p-AMPK and SIRT1) were assessed by Western blot. SNS improved serum lipid levels, liver function and reduced hepatic lipid deposition in MAFLD rats. SNS-containing serum reduced lipid deposition in PA-induced HepG2 cells. SNS could up-regulate protein expressions of PPARα, CPT-1, p-AMPK and SIRT1, and down-regulate protein expressions of SREBP-1c and FAS. Similar effects of SNS-containing serum were observed in PA-induced HepG2 cells. Meanwhile, Compound C weakened the therapeutic effects of SNS-containing serum on lipid deposition. SNS could reduce hepatic lipid deposition by inhibiting lipid synthesis and promoting fatty acid oxidation, which might be related with activating the AMPK/SIRT1 signaling pathway. This study could provide a theoretical basis for the clinical use of SNS to treat MAFLD.

Corydalis saxicola Bunting total alkaloids improve NAFLD by suppressing de novo lipogenesis through the AMPK-SREBP1 axis

Ethnopharmacological relevanceAlong with the gradually increasing incidence, nonalcoholic fatty liver disease (NAFLD) has already been influencing the health of more and more people in the world. Corydalis saxicola Bunting (CSB), a valuable folk medicine, is the dried whole grass of a perennial herb, Yanhuanglian (Papaveraceae), which has significant effects on various hepatitis, liver fibrosis, cirrhosis and other liver diseases. Corydalis saxicola Bunting total alkaloids (CSBTA), a mixture of alkaloids extracted from CSB, exhibit widely-accepted hepatoprotective effects. Aim of the studyThis study aimed to explore the therapeutic potential of CSBTA on NAFLD and the underlying mechanism. Materials and methodsA mice model was established by high fat and high cholesterol diet (HFHCD) to study the benefits of CSBTA on the progression of NAFLD. The efficacy of CSBTA on NAFLD was revealed systematically via RNA-sequencing analysis. Further efficacy and molecular mechanism study were explored in mouse primary hepatocytes and HepG2 cells stimulated with high energy with or without pharmacological inhibition or gene silencing. ResultsCSBTA effectively improved the major hallmarks of NAFLD including liver lipid accumulation, liver injury, inflammation and fibrosis in HFHCD-fed mice. RNA sequencing and targeted qPCR analysis jointly evidenced CSBTA significantly suppressed the expression of Srebf1, Acc1 and Fasn which are the genes responsible for fatty acid biosynthesis. Moreover, stable isotope tracer test denoted CSBTA reduced lipid accumulation via interrupting fatty acid biosynthesis in hepatocytes or the liver. Mechanistically, CSBTA could impede SREBP1 maturation via AMPK activation, thereby reducing DNL-derived lipid accumulation in hepatocytes. ConclusionsCSBTA protected against hepatic steatosis and other hallmarks of NAFLD induced by HFHCD via suppressing DNL, through modulating the AMPK-SREBP1 axis. CSBTA may therefore have a therapeutic potential for NAFLD treatment.

A High-Fat, High-Cholesterol Diet Promotes Intestinal Inflammation by Exacerbating Gut Microbiome Dysbiosis and Bile Acid Disorders in Cholecystectomy.

Patients with post-cholecystectomy (PC) often experience adverse gastrointestinal conditions, such as PC syndrome, colorectal cancer (CRC), and non-alcoholic fatty liver disease (NAFLD), that accumulate over time. An epidemiological survey further revealed that the risk of cholecystectomy is associated with high-fat and high-cholesterol (HFHC) dietary intake. Mounting evidence suggests that cholecystectomy is associated with disrupted gut microbial homeostasis and dysregulated bile acids (BAs) metabolism. However, the effect of an HFHC diet on gastrointestinal complications after cholecystectomy has not been elucidated. Here, we aimed to investigate the effect of an HFHC diet after cholecystectomy on the gut microbiota-BA metabolic axis and elucidate the association between this alteration and the development of intestinal inflammation. In this study, a mice cholecystectomy model was established, and the levels of IL-Iβ, TNF-α, and IL-6 in the colon were increased in mice fed an HFHC diet for 6 weeks. Analysis of fecal BA metabolism showed that an HFHC diet after cholecystectomy altered the rhythm of the BA metabolism by upregulating liver CPY7A1, CYP8B1, and BSEP and ileal ASBT mRNA expression levels, resulting in increased fecal BA levels. In addition, feeding an HFHC diet after cholecystectomy caused a significant dysbiosis of the gut microbiota, which was characterized by the enrichment of the metabolic microbiota involved in BAs; the abundance of pro-inflammatory gut microbiota and related pro-inflammatory metabolite levels was also significantly higher. In contrast, the abundance of major short-chain fatty acid (SCFA)-producing bacteria significantly decreased. Overall, our study suggests that an HFHC diet after cholecystectomy promotes intestinal inflammation by exacerbating the gut microbiome and BA metabolism dysbiosis in cholecystectomy. Our study also provides useful insights into the maintenance of intestinal health after cholecystectomy through dietary or probiotic intervention strategies.

The Effect of Fermented Momordica charantia with Leuconostoc mesenteroides MKSR on Metabolic Complications Induced by High-Fat High-Cholesterol Diet in C57BL/6 Mice

This study aimed to investigate the beneficial effects of Momordica charantia (MC) extract and MC fermented with Leuconostoc mesenteroides MKSR (FMC) on high-fat and high-cholesterol diet-induced metabolic complications. Male C57BL/6 mice were divided into six groups: normal diet (ND), high-fat and high-cholesterol diet (HFCD), HFCD with 1% MC extract (HFCD + 1M), HFCD with 4% MC extract (HFCD + 4M), HFCD with 1% fermented MC (HFCD + 1F), and HFCD with 4% fermented MC (HFCD + 4F). After 12 weeks of dietary intervention, the consumption of MC fermented with L. mesenteroides MKSR resulted in significant decreases in white adipose tissue weights (epididymal adipose tissue and retroperitoneal adipose tissue), serum alanine aminotransferase activity, and hepatic triglyceride levels. FMC also lowered total hepatic cholesterol content, improved glucose clearance during the oral glucose tolerance and insulin tolerance tests, and increased fecal cholesterol efflux from the enterohepatic circulation. Furthermore, the FMC notably increased hepatic mRNA expressions, which may indicate a compensatory mechanism against induced cholesterol efflux. Moreover, FMC induced both adipogenic (sterol regulatory element-binding protein 1c) and lipolytic (lipoprotein lipase, peroxisome proliferator-activated receptor alpha, and adiponectin) mRNA expressions. These findings suggest that fermentation with the probiotic L. mesenteroides MKSR enhances the beneficial effects of MC, preventing metabolic complications associated with a high-fat diet.

Selective autophagy associated with iron overload aggravates non-alcoholic steatohepatitis via ferroptosis.

Non-alcoholic steatohepatitis (NASH) is a progressive form of non-alcoholic fatty liver disease (NAFLD) that causes cirrhosis and hepatocellular carcinoma. Iron is an essential trace element in the body; however, excess iron can cause tissue damage and dysfunction. Iron overload is often observed in patients with NASH, and the amount of iron accumulated in the liver positively correlates with the histological severity of NASH. Ferroptosis, a novel form of iron-dependent cell death, is caused by the accumulation of lipid peroxidation and oxidative stress and is related to NASH. In addition, ferroptosis is closely related to autophagy, an intracellular self-degradation process. Although autophagy has many beneficial effects, it may also be harmful to the organism, for example, inducing ferroptosis. It is unclear whether iron overload aggravates NASH via autophagy. The aim of this research is to determine the mechanism by which iron overload induces ferroptosis via autophagy and aggravates NASH. Stroke-prone spontaneously hypertensive rats (SHRSP5/Dmcr) were divided into two groups and fed a high-fat and high-cholesterol (HFC) diet for eight weeks. Iron dextran was administered to the Fe group in addition to the HFC diet. Blood analysis, histological staining, calcineurin activity assay, quantitative reverse transcription polymerase chain reaction (RT-PCR), immunofluorescence staining, and electron microscopy were performed. The results showed that iron overload promoted autophagy via nuclear translocation of transcription factor EB (TFEB) and induced ferritinophagy, which is the autophagic degradation of ferritin. In addition, the HFC diet induced lipophagy, the autophagic degradation of lipid droplets. The Fe group also exhibited promoted ferroptosis and aggravated hepatic inflammation and fibrosis. In conclusion, iron overload accelerates ferritinophagy and lipophagy, aggravating NASH pathology via ferroptosis. These findings indicate the therapeutic potential of inhibiting autophagy and ferroptosis for treating NASH.

Through regulation of the SIRT1 pathway plant sterol ester of α-linolenic acid inhibits pyroptosis thereby attenuating the development of NASH in mice

Increasing evidence demonstrated that pyroptosis and subsequent inflammation played an important role in the pathological process of non-alcoholic steatohepatitis (NASH). Plant sterol ester of α-linolenic acid (PS-ALA) was beneficial for non-alcoholic fatty liver disease, but the underlying mechanisms are still not fully understood. This study aims to investigate whether PS-ALA can protect against proptosis via regulating SIRT1. Thirty male C57BL/6J mice were fed a normal diet, a high-fat and high-cholesterol diet (HFCD), or a HFCD supplemented with either 1.3%ALA, 2%PS, or 3.3% PS-ALA for 24 weeks. Hepatocytes were treated with oleic acid and cholesterol (OA/Cho) with or without PS-ALA. We found that PS-ALA ameliorated NASH in HFCD-fed mice. In addition, PS-ALA decreased the expression of NLRP3 and ASC and reduced the co-localization of NLRP3 and cleave-Caspase-1. Also, PS-ALA protected against pyroptosis as evidenced by decreased co-localization of GSDMD and propidium iodide (PI) positive cells. Mechanistically, we revealed that the inhibitory action of PS-ALA on the pyroptosis was mediated by SIRT1. This was demonstrated by the fact that silencing SIRT1 with small interfering RNA or inhibition of SIRT1 with its inhibitor abolished the inhibition effect of PS-ALA on the expression of NLRP3 and GSDMD cleavage. Collectively, the data from the present study reveals a novel mechanism that PS-ALA inhibits pyroptosis and it triggered inflammation via stimulating SIRT1, which provides new insights into the beneficial effect of PS-ALA on NASH.

Stigmasterol Protects Against Steatohepatitis Induced by High-Fat and High-Cholesterol Diet in Mice by Enhancing the Alternative Bile Acid Synthesis Pathway

BackgroundHepatic cholesterol accumulation is a significant risk factor in the progression of nonalcoholic fatty liver disease (NAFLD) to steatohepatitis. However, the precise mechanism by which stigmasterol (STG) mitigates this process remains unclear. ObjectivesThis study aimed to investigate the potential mechanism underlying the protective effect of STG in mice with NAFLD progressing to steatohepatitis while being fed a high-fat and high-cholesterol (HFHC) diet. MethodsMale C57BL/6 mice were fed an HFHC diet for 16 wk to establish the NAFLD model. Subsequently, the mice received STG or a vehicle via oral gavage while continuing the HFHC diet for an additional 10 wk. The study evaluated hepatic lipid deposition and inflammation as well as the expression of key rate-limiting enzymes involved in the bile acid (BA) synthesis pathways. BAs in the colonic contents were quantified using ultra-performance liquid chromatography-tandem mass spectrometry. ResultsCompared with the vehicle control group, STG significantly reduced hepatic cholesterol accumulation (P < 0.01) and suppressed the gene expression of NLRP3 inflammasome and interleukin-18 (P < 0.05) in the livers of HFHC diet-fed mice. The total fecal BA content in the STG group was nearly double that of the vehicle control group. Additionally, the administration of STG increased the concentrations of representative hydrophilic BAs in the colonic contents (P < 0.05) along with the upregulation of gene and protein expression of CYP7B1 (P < 0.01). Furthermore, STG enhanced the α-diversity of the gut microbiota and partially reversed the alterations in the relative abundance of the gut microbiota induced by the HFHC diet. ConclusionsSTG mitigates steatohepatitis by enhancing the alternative pathway for BA synthesis.

Antioxidant action of xanthine oxidase inhibitor febuxostat protects the liver and blood vasculature in SHRSP5/Dmcr rats.

Xanthine oxidase (XO) generates reactive oxygen species during uric acid production. Therefore, XO inhibitors, which suppress oxidative stress, may effectively treat non-alcoholic steatohepatitis (NASH) and atherosclerosis via uric acid reduction. In this study, we examined the antioxidant effect of the XO inhibitor febuxostat on NASH and atherosclerosis in stroke-prone spontaneously hypertensive 5 (SHRSP5/Dmcr) rats. SHRSP5/Dmcr rats were divided into three groups: SHRSP5/Dmcr + high-fat and high-cholesterol (HFC) diet [control group, n = 5], SHRSP5/Dmcr + HFC diet + 10% fructose (40 ml/day) [fructose group, n = 5], and SHRSP5/Dmcr + HFC diet + 10% fructose (40 ml/day) + febuxostat (1.0 mg/kg/day) [febuxostat group, n = 5]. Glucose and insulin resistance, blood biochemistry, histopathological staining, endothelial function, and oxidative stress markers were evaluated. Febuxostat reduced the plasma uric acid levels. Oxidative stress-related genes were downregulated, whereas antioxidant factor-related genes were upregulated in the febuxostat group compared with those in the fructose group. Febuxostat also ameliorated inflammation, fibrosis, and lipid accumulation in the liver. Mesenteric lipid deposition decreased in the arteries, and aortic endothelial function improved in the febuxostat group. Overall, the XO inhibitor febuxostat exerted protective effects against NASH and atherosclerosis in SHRSP5/Dmcr rats.

Partial replacement of high-fat diet with n-3 PUFAs enhanced beef tallow attenuates dyslipidemia and endoplasmic reticulum stress in tunicamycin-injected rats.

Metabolic syndrome (MetS) is considered as a complex, intertwined multiple risk factors that directly increase the risk of various metabolic diseases, especially cardiovascular atherosclerotic diseases and diabetes mellitus type 2. While lifestyle changes, including dietary intervention are effective in mitigating or preventing MetS, there are no specific therapies against MetS. Typical western diets comprise of high saturated fatty acid, cholesterol, and simple sugar; consequently their consumption may increase the potential pathological developmental risk of MetS. Partial replacement of dietary fatty acids with polyunsaturated fatty acids (PUFAs) is widely recommended measure to manage MetS-related disorders. In the present study, we used rat model to investigate the role of n-3 PUFA enriched beef tallows (BT) on MetS and tunicamycin (TM)-induced endoplasmic reticulum (ER) stress, by partially replacing dietary fat (lard) with equal amounts of two different BTs; regular BT or n-3 PUFA-enriched BT. The experimental rats were randomly assigned to three different dietary groups (n = 16 per group): (1) high-fat and high-cholesterol diet (HFCD); (2) HFCD partially replaced with regular BT (HFCD + BT1); (3) HFCD partially replaced with n-3 enhanced BT (w/w) (HFCD + BT2). After 10 weeks of dietary intervention, each experimental rodent was intraperitoneally injected with either phosphate-buffered saline or 1 mg/kg body weight of TM. HFCD + BT2 showed improved dyslipidemia before TM injection, and increased serum high-density lipoprotein cholesterol (HDL-C) levels after TM injection. BT replacement groups had significantly reduced hepatic triglyceride (TG) levels, and decreased total cholesterol (TC) and TG levels in epididymal adipose tissue (EAT). Furthermore, BT replacement remarkably attenuated TM-induced unfolded protein responses (UPRs) in liver, showing reduced ER stress, with BT2 being more effective in the EAT. Therefore, our findings suggest that partially replacing dietary fats with n-3 PUFA to lower the ratio of n-6/n-3 PUFAs is beneficial in preventing pathological features of MetS by alleviating HFCD- and/or TM-induced dyslipidemia and ER stress.

Supplementation with Natto and Red Yeast Rice Alters Gene Expressions in Cholesterol Metabolism Pathways in ApoE-/- Mice with Concurrent Changes in Gut Microbiota.

We aimed to examine the effect of natto and red yeast rice (NR) supplementation on lipid and lipoprotein profiles, gene expressions of cholesterol metabolism, and the composition of gut microbiota in ApoE-/- mice. Forty-one male ApoE-/- mice aged 7-8 wks old were randomly fed a control diet (CD), CD + NR (oral gavage at 0.3 g/kg BW/day), high-fat and high-cholesterol diet (HFD), or HFD + NR for 12 wks. Fasting blood samples, liver and intestine tissues and fecal samples were collected at week 12. Biochemical parameters, gene expressions in cholesterol metabolism and gut microbiota composition and diversity were measured using standard methods. NR supplementation had no significant effect on lipid and lipoprotein profiles. Compared with the HFD group, HFD + NR resulted in higher mRNA expressions of HMGCR and CYP7A1 (both P-NR < 0.05) and ABCA1 (P-diet*NR = 0.0134, P-NR = 0.0407), lower mRNA expression of PCSK9 (P-diet*NR = 0.0002), lower fasting glucose concentrations (P-diet*NR = 0.0011), and lower relative abundance of genera Bacteroides and Lactococcus (both P-NR < 0.01) and Coriobacteriaceae_UCG-002 (P-diet*NR = 0.0007). The relative abundance of Lactococcus was inversely correlated with HMGCR and CYP7A1, and the relative abundance of Coriobacteriaceae_UCG-002 was positively correlated with PCSK9 and inversely correlated with ABCA1 (all P < 0.05). These findings suggest that NR supplementation may regulate gene expressions in cholesterol metabolism via changes in the gut microbiota in HFD-fed ApoE-/- mice.

Dietary Cholic Acid Exacerbates Liver Fibrosis in NASH Model of Sprague-Dawley Rats Fed a High-Fat and High-Cholesterol Diet.

Background: Recently, we established a novel rodent model of nonalcoholic steatohepatitis (NASH) with advanced fibrosis induced by a high-fat and high-cholesterol (HFC) diet containing cholic acid (CA), which is known to cause hepatotoxicity. The present study aimed to elucidate the direct impact of dietary CA on the progression of NASH induced by feeding the HFC diet. Methods: Nine-week-old male Sprague–Dawley rats were randomly assigned to receive a normal, HFC, or CA-supplemented (0.1%, 0.5% or 2.0%, w/w) HFC diet for 9 weeks. Results: Histopathological assessment revealed that the supplementation of CA dose-dependently aggravated hepatic steatosis, inflammation, and fibrosis, reaching stage 4 cirrhosis in the 2.0% CA diet group. In contrast, the rats that were fed the HFC diet without any added CA developed mild steatosis and inflammation without fibrosis. The hepatic cholesterol content and mRNA expression involved in inflammatory response and fibrogenesis was higher in a CA dose-dependent manner. The hepatic chenodeoxycholic acid levels were higher in 2.0% CA diet group than in the control, although hepatic levels of total bile acid and CA did not increase dose-dependently with CA intake. Conclusion: Adding CA to the HFC diet altered bile acid metabolism and inflammatory response and triggered the development of fibrosis in the rat liver.

Effects of Dietary Inclusion of β-Hydroxy-β-Methylbutyrate on Growth Performance, Fat Deposition, Bile Acid Metabolism, and Gut Microbiota Function in High-Fat and High-Cholesterol Diet-Challenged Layer Chickens.

Excessive lipid deposition in layer chickens due to inappropriate feeding adversely affects egg production; however, nutritional manipulation methods to deal with this issue are still limited. β-hydroxy-β-methylbutyrate (HMB), a metabolite of L-leucine, was recently reported as a lipid-lowering nutrient in mice and pigs, although its role in layers had not been investigated. Here, we employed high-fat and high-cholesterol diet (HFHCD)−challenged growing layers as an obese model to explore HMB function in the regulation of lipid metabolism and the potential mechanisms involved. We found that dietary supplementation with (0.05% or 0.10%) HMB significantly reduced HFHCD−induced bodyweight growth in layers, mainly due to reduction in abdominal fat deposition. Mechanistically, HMB supplementation enhanced hepatic bile acid synthesis from cholesterol through elevating expression of Cyp7a1, a gene coding a key enzyme in bile acid synthesis. Furthermore, 16S rRNA gene sequencing revealed that HMB supplementation remodeled the diversity and composition of the layers’ cecal microbiota, and the abundance of Bacteroidetes at the phylum level were especially affected. Correlation analysis further indicated a strong negative association between Bacteroidetes abundance and lipid metabolism−related parameters. Taken together, these data suggest that dietary HMB supplementation could improve abdominal fat deposition in layers, probably through modulating hepatic bile acid synthesis and gut microbiota function.