Influence of dietary sucrose and copper content in a rat model of non-alcoholic fatty-liver disease
ABSTRACT: Nutrigenomics analysis was used to investigate the molecular responses to dietary Cu deficiency independently and in combination with 30% (w/w) sucrose in a mature rat model of NAFLD. Low Cu significantly decreased hepatic and serum Cu, and induced NAFLD-like histopathology, mild steatosis, up-regulated transcripts in inflammation and hepatic stellate cell activation, and significantly increased oxidative stress. Rats fed low Cu together with 30% sucrose also developed insulin resistance, increased ATP citrate lyase and FASN expression, and greater oxidative stress. High sucrose with adequate Cu also promoted inflammation and fibrosis, but not steatosis. This study indicates that low dietary Cu and sucrose consumption are singular and synergistic dietary factors in promotion of NAFLD and NASH that act independently of obesity or severe steatosis, likely by promoting oxidative stress and activation of inflammation and fibrosis. Mature (6 months old) male Wistar Rats that had been allowed ad libitum access to Mazuri rodent pellets were used in the study. Twenty-four rats were divided into four groups and fed for 12 weeks with diets based on the Purified AIN76A formulation, modified for target sucrose and Cu content (Custom Animal Diets, Bangor, NJ). Sucrose and copper content in diets were as follows: ‘A’ CuD/30%- Cu deficient (<0.3 mg Cu/kg)/30% sucrose, ‘B’ CuA/30%- Cu adequate (125 mg/kg)/30% sucrose, ‘C’ CuD/10%- <0.3 mg/kg Cu/10% sucrose, and ‘D’ CuA (125 mg/kg Cu)/10% sucrose (control). Starch and dextrin were used to equalize carbohydrates.
Project description:High intakes of carbohydrates, particularly sucrose, in Western societies are associated with the development of non-alcoholic fatty liver (NAFL) and diabetes mellitus. It is unclear whether this is related to the carbohydrate quantity or the hormonal responses, particularly Glucose-dependent Insulinotropic Polypeptide (GIP) which is released in the proximal intestine. We, therefore, used the glucose-fructose dimer as proximally resorbed, 1,4-linked sucrose or distally resorbed 1,6-linked palatinose. Palatinose compared to sucrose, indeed, resulted in slower glucose absorption and reduced postprandial insulin and GIP levels. After 22 weeks of isocaloric diets, palatinose feeding prevented hepatic steatosis (48.5%) compared to sucrose and improved glucose tolerance, without differences in body composition and food intake. Ablation of GIP receptor (GIPR) signaling in Gipr-/- mice completely prevented the deleterious metabolic effects of sucrose feeding. Furthermore, our microarray analysis indicated that sucrose increased the hepatic expression of Suppressor of Cytokine Signaling 2 (SOCS2), which is involved in the growth hormone signaling pathway and participates in the development of NAFL. Our results suggest that the site of glucose absorption and the GIP response determine liver fat accumulation and insulin resistance. GIP may play a role in sucrose induced fatty liver by regulating the expression of SOCS2. Expression data from liver tissue of mice fed with isocaloric diets containing either sucrose or palatinose
Project description:With an estimated prevalence of about 30% in western countries non-alcoholic fatty liver disease (NAFLD) is a major public health issue [PMID: 18956290]. NAFLD is associated with the metabolic syndrome of insulin resistance, obesity, glucose intolerance. Although many studies are pointing to an induction of insulin resistance by NAFLD causality between both phenotypes is not fully clarified. Furthermore, mechanisms leading to strongly differing progression of NAFLD have to be elucidated which range from mild steatosis up to severe steatohepatitis. Steatohepatitis might even result in liver cirrhosis and hepatocellular carcinoma. Additional complexity is introduced into the understanding of the disease by recent studies providing evidence for a direct development of carcinoma from steatosis without the formerly assumed intermediary phase of cirrhosis. Here, we investigate liver samples from patients with varying severities of steatosis in an integrative approach employing transcriptomics, serum biomarker profling, metabolomics data and systems biology models. Total RNA obtained from hepatocytes derived from nine obese patients with distinct grades of steatosis.
Project description:Nonalcoholic fatty liver disease represents a spectrum of pathology that ranges from benign steatosis to potentially-progressive steatohepatitis and affects more than 30% of US adults. Advanced NAFLD is associated with increased morbidity and mortality from cirrhosis, primary liver cancer, cardiovascular disease and extrahepatic cancers. Accurate identification of patients at risk for advanced NAFLD is challenging. The aims of this study were to define the liver gene expression patterns that distinguish mild from advanced NAFLD and to develop a gene expression profile associated with advanced NAFLD. We analyzed total RNA from 72 patients with NAFLD (40 with mild NAFLD, fibrosis stage 0-1 and 32 with advanced NAFLD, fibrosis stage 3-4) and developed a gene profile associated with advanced NAFLD.
Project description:The physiological adaptations of diatoms to cope with Cu limitation are largely unknown. In the present study we investigated the response to Cu limitation in two strains of the model open ocean diatom T. oceanica (CCMP 1003 and CCMP 1005), focusing on physiological and proteomic changes in the photosynthetic apparatus. Our results show remarkable differences between the adaptations of TO05 and TO03 to low Cu, highlighting significant intra specific variations.
Project description:Zebrafish (n=420; 70/treatment) were weighed and placed in 8L aerated tanks,<br>served with flow-through soft-water at 25ml/min. A combination of Mariotte bottles<br>were used to dose tanks with Cu (concentrated Cu solution made from CuSO4 dissolved<br>in 0.05% HNO3), Na (concentrated NaCl solution), and Ca (concentrated CaCl2 solution)<br>to 6 treatment regimes of either control (Ctrl), Cu only (Cu), high Ca only (Ca), Ca + Cu<br>(CaCu), high Na only (Na), and Na + Cu (NaCu; See Table 1 for ion concentrations).<br>Nitric acid had no measurable impact on water pH. Fish were fed 2% body weight of<br>commercial tropical fish food, once per day. Tanks were monitored daily for mortality<br>and cleaned of any food or waste that had accumulated. Water samples (10 ml) were<br>taken from each tank, filtered though a 0.45?m filtration disc (Pall Corporation, East<br>Hills, NY), added to a plastic tube containing 100?l HNO3 and kept at 4oC for analysis of<br>ion content and Cu concentration. Throughout the experiment, there were no mortalities<br>in any of the tanks. At the end of the exposure period, fish were quickly euthanized by<br>overdose of buffered aesthetic (MS-222, Sigma) and sampled for gill, liver, and gut,<br>which were immediately frozen in liquid N2 for further analysis of Cu burden, gene<br>expression, and enzyme activity.
Project description:Nonalcoholic fatty liver disease (NAFLD) has become the most common cause of liver disease affecting 20-30% of the population in developed countries. NAFLD is strongly associated with abdominal obesity and is recognized as the hepatic manifestation of the metabolic syndrome. In a subgroup of patients with NAFLD inflammation and fibrosis develops, this so-called Non-Alcoholic Steatohepatitis (NASH) may progress to cirrhosis and hepatocellular carcinoma. A multi-hit hypothesis has been proposed in which during the first “hit” fat accumulation occurs in hepatocytes from excessive delivery of fatty acids from adipose tissue, in addition there is an imbalance in lipid synthesis and export. However, the reason why fat accumulation is subsequently followed by inflammation and fibrosis in some patients is poorly understood. We studied the role of gene expression at the transcriptional level using microarray in bariatric patients from whom the liver histology was available. Patients scheduled for bariatric surgery were recruited in Pretoria/South-Africa. At the time of the procedure, tissue samples of the visceral and subcutaneous fat were taken for molecular analysis as well as liver tissue for histology, also full biochemical data was collected. Patients were grouped according histology: group I (<5% steatosis), group II (NAFLD, 30-50% steatosis) and group III (NASH). The 15 samples were used for microarray (nr patients respectively for stages I-II-III: 6-4-5).
Project description:Non-alcoholic fatty liver disease (NAFLD) encompasses a spectrum of histological findings, from simple steatosis to steatohepatitis (NASH), the latter presenting a higher risk of cardiovascular and kidney diseases, type 2 diabetes and end-stage liver disease. NAFLD is seen as the hepatic manifestation of the metabolic syndrome and affects up to 70-80% of obese patients. There are currently no approved pharmacological therapies for NASH, thus the only option is lifestyle intervention or bariatric surgery in order to lose weight and to improve insulin resistance. Although surgical intervention has allowed collections of liver biopsies, transcriptomic data from livers are still scarce and especially follow-up data to evaluate the impact of weight loss intervention on the liver. Therefore we studied hepatic transcriptomic data in a large cohort of obese patients assessed for presence of NASH at baseline and 1 year follow-up. Patients visiting the obesity clinic of the Antwerp University Hospital for a problem of being overweight (BMI above 25 to 29.9 kg/m²) or obese (BMI above 30 kg/m²) were prospectively recruited and underwent a hepatic work-up. Patients were excluded from further analysis in case of significant alcohol consumption (>20 g/day), history of bariatric surgery, diagnosis of another liver disease, pre-existing diabetes. Patients who were, however, diagnosed with de novo diabetes at baseline or at follow-up were not excluded. If NAFLD was suspected, liver biopsy was proposed. For patients undergoing bariatric surgery (BS), a liver biopsy was proposed regardless of the criteria. Patients were reassessed after 1 year. Liver biopsy was performed percutaneously (16G Menghini) or peri-operatively (14G Tru-Cut). The different histological features of NAFLD were assessed using the NASH Clinical Research Network (NASH CRN) Scoring System. The presence of NASH was defined according to Chalasani et al. necessitating the combined presence of steatosis, ballooning and lobular inflammation. Overall design: Microarray data were obtained for 152 patients at baseline (44 no NASH, 104 NASH, 4 undefined) and 79 patients (54 no NASH, 22 NASH, 3 undefined) at 1 year follow-up (38 diet restriction [Diet], 41 bariatric surgery [BS]). When paired (baseline - follow-up) samples were available, the number in brackets in Sample name indicates the baseline number of the same patient.
Project description:Anthropogenic pollution has increased the levels of heavy metals in the environment. Bacterial populations continue to thrive in highly polluted environments and bacteria must have mechanisms to counter heavy metal stress. We chose to examine the response of the environmentally-relevant organism Pseudomonas aeruginosa to two different copper treatments. A short, 45 min exposure to copper was done in the Cu shock treatment to examine the immediate transcriptional profile to Cu stress. The Cu adapted treatment was designed to view the transcriptional profile of cells that were actively growing in the presence of Cu. Experiment Overall Design: We analyzed 2 biological replicates of Pseudomonas aeruginosa exposed to a 45 min Cu shock as compared to a control that was exposed to HCl to bring the pH to similar levels. We analyzed 2 biological replicates of Pseudomonas aeruginosa that were grown in the presence of Cu for approx. 6h (Cu adapted) as compared to an untreated control.
Project description:Objective: Nonalcoholic fatty liver disease (NAFLD) is linked to obesity and diabetes, suggesting an important role of adipose tissue in the pathogenesis of NAFLD. Here we aim to investigate the interaction between adipose tissue and liver in NAFLD, and identify potential early plasma markers that predict NASH. Research Design and Methods: C57Bl/6 mice were chronically fed a high fat diet to induce NAFLD and compared with mice fed low fat diet. Extensive histological and phenotypical analyses coupled with a time-course study of plasma proteins using multiplex assay was performed. Results: Mice exhibited pronounced heterogeneity in liver histological scoring, leading to classification into 4 subgroups: LF-low (LFL) responders displaying normal liver morphology, LF-high (LFH) responders showing benign hepatic steatosis, HF-low (HFL) responders displaying pre-NASH with macrovesicular lipid droplets, and HF-high (HFH) responders exhibiting overt NASH characterized by ballooning of hepatocytes, presence of Mallory bodies, and activated inflammatory cells. Compared to HFL responders, HFH mice gained weight more rapidly and exhibited adipose tissue dysfunction characterized by decreased final fat mass, enhanced macrophage infiltration and inflammation, and adipose tissue remodelling. Plasma haptoglobin, IL-1β, TIMP-1, adiponectin and leptin were significantly changed in HFH mice. Multivariate analysis indicated that in addition to leptin, plasma CRP, haptoglobin, eotaxin and MIP-1α early in the intervention were positively associated with liver triglycerides. Intermediate prognostic markers of liver triglycerides included IL-18, IL-1β, MIP-1γ and MIP-2, whereas insulin, TIMP-1, GCP-2 and MPO emerged as late markers. Conclusions: Our data support the existence of a tight relationship between adipose tissue dysfunction and NASH pathogenesis and point to several novel potential predictive biomarkers for NASH. Keywords: Expression profiling by array Male wildtype C57Bl/6 mice were fed LFD or HFD for 21 weeks. Mice were divided into 4 groups based on liver histology.
Project description:We aim to establish NAFLD model of Zebrafish. Zebrafish larvae fed with high cholesterol diet，high fructose diet and overfeed diet to induce liver steatosis. RNA-seq was employed to analyze the effects of different diets on NAFLD development.