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Obese Mice (obese + mouse)
Selected AbstractsAdministration of myostatin does not alter fat mass in adult miceDIABETES OBESITY & METABOLISM, Issue 2 2008L. E. Stolz Aim: Myostatin, a member of the TGF-beta superfamily, is produced by skeletal muscle and acts as a negative regulator of muscle mass. It has also been suggested that low-dose administration of myostatin (2 ,g/day) in rodents can reduce fat mass without altering muscle mass. In the current study, we attempted to further explore the effects of myostatin on adipocytes and its potential to reduce fat mass, since myostatin administration could potentially be a useful strategy to treat obesity and its complications in humans. Methods: Purified myostatin protein was examined for its effects on adipogenesis and lipolysis in differentiated 3T3-L1 adipocytes as well as for effects on fat mass in wild-type, myostatin null and obese mice. Results: While myostatin was capable of inhibiting adipogenesis in 3T3-L1 cells, it did not alter lipolysis in fully differentiated adipocytes. Importantly, pharmacological administration of myostatin over a range of doses (2,120 ,g/day) did not affect fat mass in wild-type or genetically obese (ob/ob, db/db) mice, although muscle mass was significantly reduced at the highest myostatin dose. Conclusions: Our results suggest that myostatin does not reduce adipose stores in adult animals. Contrary to prior indications, pharmacological administration of myostatin does not appear to be an effective strategy to treat obesity in vivo. [source] Obesity predisposes to Th17 biasEUROPEAN JOURNAL OF IMMUNOLOGY, Issue 9 2009Shawn Winer Abstract Obesity is associated with numerous inflammatory conditions including atherosclerosis, autoimmune disease and cancer. Although the precise mechanisms are unknown, obesity-associated rises in TNF-,, IL-6 and TGF-, are believed to contribute. Here we demonstrate that obesity selectively promotes an expansion of the Th17 T-cell sublineage, a subset with prominent pro-inflammatory roles. T-cells from diet-induced obese mice expand Th17 cell pools and produce progressively more IL-17 than lean littermates in an IL-6-dependent process. The increased Th17 bias was associated with more pronounced autoimmune disease as confirmed in two disease models, EAE and trinitrobenzene sulfonic acid colitis. In both, diet-induced obese mice developed more severe early disease and histopathology with increased IL-17+ T-cell pools in target tissues. The well-described association of obesity with inflammatory and autoimmune disease is mechanistically linked to a Th17 bias. [source] Fatty acids increase the circulating levels of oxidative stress factors in mice with diet-induced obesity via redox changes of albuminFEBS JOURNAL, Issue 15 2007Mayumi Yamato Plasma concentrations of free fatty acids are increased in metabolic syndrome, and the increased fatty acids may cause cellular damage via the induction of oxidative stress. The present study was designed to determine whether the increase in fatty acids can modify the free sulfhydryl group in position 34 of albumin (Cys34) and enhance the redox-cycling activity of the copper,albumin complex in high-fat diet-induced obese mice. The mice were fed with commercial normal diet or high-fat diet and water ad libitum for 3 months. The high-fat diet-fed mice developed obesity, hyperlipemia, and hyperglycemia. The plasma fatty acid/albumin ratio also significantly increased in high-fat diet-fed mice. The increased fatty acid/albumin ratio was associated with conformational changes in albumin and the oxidation of sulfhydryl groups. Moreover, an ascorbic acid radical, an index of redox-cycling activity of the copper,albumin complex, was detected only in the plasma from obese mice, whereas the plasma concentrations of ascorbic acid were not altered. Plasma thiobarbituric acid reactive substances were significantly increased in the high-fat diet group. These results indicate that the increased plasma fatty acids in the high-fat diet group resulted in the activated redox cycling of the copper,albumin complex and excessive lipid peroxidation. [source] Adiponectin protects LPS-induced liver injury through modulation of TNF-, in KK-Ay obese miceHEPATOLOGY, Issue 1 2004Takayuki Masaki Adiponectin, an adipocytokine, has been identified in adipose tissue, and its receptors are widely distributed in many tissues, including the liver. The present study was performed to clarify the role of adiponectin in lipopolysaccharide (LPS)-induced liver injury using KK-Ay obese mice. We analyzed the effects of adiponectin pretreatment on liver injury induced by D -galactosamine/LPS (GalN/LPS) in KK-Ay obese mice. GalN/LPS treatment induced significant increases in aspartate aminotransferase (AST) and alanine aminotransferase (ALT) levels in the blood, apoptotic and necrotic changes in hepatocytes, and/or showed a high degree of lethality. The GalN/LPS-induced liver injury was more pronounced in KK-Ay obese mice than in lean controls. Pretreatment with adiponectin ameliorated the GalN/LPS-induced elevation of serum AST and ALT levels and the apoptotic and necrotic changes in hepatocytes, resulting in a reduction in lethality. In addition, pretreatment with adiponectin attenuated the GalN/LPS-induced increases in serum and hepatic tumor necrosis factor , (TNF-,) levels and increased peroxisome proliferator-activated receptor (PPAR) , messenger RNA expression in the liver. Furthermore, abdominal macrophages from KK-Ay obese mice pretreated with adiponectin in vitro exhibited decreased LPS-induced TNF-, production compared with controls. Finally, adiponectin pretreatment also ameliorated TNF-,-induced liver injury. In conclusion, these findings suggest that adiponectin prevents LPS-induced hepatic injury by inhibiting the synthesis and/or release of TNF-, of KK-Ay obese mice. (HEPATOLOGY 2004;40:177,184.) [source] Nonalcoholic fatty pancreas diseaseHPB, Issue 4 2007Abhishek Mathur Abstract Background. Obesity leads to fat infiltration of multiple organs including the heart, kidneys, and liver. Under conditions of oxidative stress, fat-derived cytokines are released locally and result in an inflammatory process and organ dysfunction. In the liver, fat infiltration has been termed nonalcoholic fatty liver disease, which may lead to nonalcoholic steatohepatitis. No data are available, however, on the influence of obesity on pancreatic fat and cytokines, and nonalcoholic fatty pancreas disease (NAFPD) has not been described. Therefore, we designed a study to determine whether obesity is associated with increased pancreatic fat and cytokines. Materials and methods. Thirty C57BL/6J lean control and 30 leptin-deficient obese female mice were fed a 15% fat diet for 4 weeks. At 12 weeks of age all animals underwent total pancreatectomy. Pancreata from each strain were pooled for measurement of a) wet and dry weight, b) histologic presence of fat, c) triglycerides, free fatty acids (FFAs), cholesterol, phospholipids, and total fat, and d) interleukin (IL)-1, and tumor necrosis factor-alpha (TNF-,). Data were analyzed by Student's t test and Fisher's exact test. Results. Pancreata from obese mice were heavier (p<0.05) and had more fat histologically (p<0.05). Pancreata from obese mice had more triglycerides, FFAs, cholesterol, and total fat (p<0.05). Triglycerides represented 11% of pancreatic fat in lean mice compared with 67% of pancreatic fat in obese mice (p<0.01). Cytokines IL-1, and TNF-, also were elevated in the pancreata of obese mice (p<0.05). Conclusions. These data suggest that obese mice have 1) heavier pancreata, 2) more pancreatic fat, especially triglycerides and FFAs, and 3) increased cytokines. We conclude that obesity leads to nonalcoholic fatty pancreatic disease. [source] Severe pulmonary metastasis in obese and diabetic miceINTERNATIONAL JOURNAL OF CANCER, Issue 12 2006Akinori Mori Abstract Although obesity is known as a risk factor for several human cancers, the association of obesity with cancer recurrence and metastasis remains to be characterized. Here, B16-BL6 melanoma and Lewis lung carcinoma cells were intravenously injected into diabetic (db/db) and obese (ob/ob) mice. The number of experimental lung colonies was markedly promoted in these mice when compared with C57BL/6 mice. In contrast, tumor growth at the implanted site was comparable when cells were inoculated orthotopically. The use of B16-BL6 cells stably transfected with the luciferase gene revealed that the increased metastasis reflected a difference mainly within 6 hr after the intravenous inoculation of tumor cells. Administration of recombinant leptin in ob/ob mice abolished the increase in metastasis early on as well as the decrease in the splenic NK cell number. In addition, depletion of NK cells by an anti-asialo-GM1 antibody abrogated the enhanced metastasis in db/db mice. These results demonstrate that metastasis is markedly promoted in diabetic and obese mice mainly because of decreased NK cell function during the early phase of metastasis. © 2006 Wiley-Liss, Inc. [source] Dual action of apolipoprotein E-interacting HCCR-1 oncoprotein and its implication for breast cancer and obesityJOURNAL OF CELLULAR AND MOLECULAR MEDICINE, Issue 9b 2009Seon-Ah Ha Abstract Obese women have an increased risk for post-menopausal breast cancer. The physiological mechanism by which obesity contributes to breast tumourigenesis is not understood. We previously showed that HCCR-1 oncogene contributes to breast tumourigenesis as a negative regulator of p53 and detection of HCCR-1 serological level was useful for the diagnosis of breast cancer. In this study, we found that the HCCR-1 level is elevated in breast cancer tissues and cell lines compared to normal breast tissues. We identified apolipoprotein E (ApoE) interacting with HCCR-1. Our data show that HCCR-1 inhibits anti-proliferative effect of ApoE, which was mediated by diminishing ApoE secretion of breast cancer cells. Finally, HCCR-1 induced the severe obesity in transgenic mice. Those obese mice showed severe hyperlipidaemia. In conclusion, our results suggest that HCCR-1 might play a role in the breast tumourigenesis while the overexpression of HCCR-1 induces the obesity probably by inhibiting the cholesterol-lowering effect of ApoE. Therefore, HCCR-1 seems to provide the molecular link between the obesity and the breast cancer risk. [source] Stevia rebaudiana Bertoni extract supplementation improves lipid and carnitine profiles in C57BL/6J mice fed a high-fat dietJOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 7 2010Jeong-Eun Park Abstract BACKGROUND: Stevia (Stevia rebaudiana Bertoni) is a non-caloric natural-source alternative to artificially produced sugar substitutes. This study investigated the effect of stevia extract on lipid profiles in C57BL/6J mice. Forty mice were divided into four groups: N-C (normal diet and distilled water), H-C (high-fat diet and distilled water), H-SC (high fat diet and sucrose, 1 mL kg,1 per day), and H-SV (high-fat diet and stevia extract, 1 mL kg,1 per day). RESULTS: Body weight gain was significantly higher in the H-SC group than in the H-SV group. Triglyceride concentrations in serum and liver were lower in the H-SV group than in the H-SC group. Serum total cholesterol concentrations were lower in the H-SV and H-C groups compared to the H-SC group. The concentrations of acid-insoluble acylcarnitine (AIAC) in serum were higher in the H-SV group than in the H-C and H-SC groups and the acyl/free carnitine level in liver was significantly higher in the H-SV group than in the N-C group. These results were supported by mRNA expression of enzymes related to lipid metabolism (ACO, PPAR,, ACS, CPT-I, ACC) assessed by real-time polymerase chain reaction. CONCLUSION: These results suggest that the supplementation of stevia extract might have an anti-obesity effect on high-fat diet induced obese mice. Copyright © 2010 Society of Chemical Industry [source] Plasminogen activator inhibitor-1 contributes to the deleterious effect of obesity on the outcome of thrombotic ischemic stroke in miceJOURNAL OF THROMBOSIS AND HAEMOSTASIS, Issue 8 2007N. NAGAI Summary.,Background:,It is widely accepted that obesity is a risk factor for ischemic heart disease, but the association with stroke is less clear. Adipose tissue is an important source of plasminogen activator inhibitor-1 (PAI-1), the main inhibitor of plasminogen activation. Objective:,To test the hypothesis that elevated PAI-1 levels associated with obesity negatively affect the outcome of thrombotic ischemic stroke. Methods:,Middle cerebral artery (MCA) occlusion was induced photochemically in mice with nutritionally induced or genetically determined obesity and their lean counterparts. Results:,The MCA occlusion time (to obtain complete occlusion) was significantly shorter in obese (nutritionally induced) than in lean wild-type (WT) C57Bl/6 mice, whereas the infarct size was significantly larger and intracranial hemorrhage (ICH) was enhanced (all P < 0.05). Similar observations were made in genetically obese ob/ob mice, as compared to lean WT littermates. In both strains, obesity was associated with markedly elevated circulating PAI-1 levels, probably originating from the fat tissue. In contrast, PAI-1-deficient lean and obese mice did not display significant differences in MCA occlusion time, infarct volume or ICH. Conclusions:,Plasminogen activator inhibitor-1 may play a functional role in the deleterious effect of obesity on the outcome of thrombotic ischemic stroke in mice. [source] Hepatic protein expression of lean mice and obese diabetic mice treated with peroxisome proliferator-activated receptor activatorsPROTEINS: STRUCTURE, FUNCTION AND BIOINFORMATICS, Issue 4 2003Ulrika Edvardsson Abstract The peroxisome proliferator-activated receptors (PPARs) are ligand-activated transcription factors that modulate lipid and glucose homeostasis. In the clinic, PPAR, and PPAR, agonists are used to treat hypertriglyceridemia and insulin resistance of diabetes, respectively. To gain further insight into the molecular mechanisms underlying the therapeutic actions of these drugs, we have by two-dimensional electrophoresis and mass spectrometry performed a comparative analysis of the hepatic protein expression profiles of lean and obese (ob/ob) mice, and obese mice treated with WY14,643 (PPAR, agonist) or rosiglitazone (PPAR, agonist). We found that livers from obese mice displayed higher levels of enzymes involved in fatty acid oxidation and lipogenesis compared to lean mice and these differences were further amplified by treatment with both PPAR activators. WY14,643 normalized the expression levels of several enzymes involved in glycolysis, gluconeogenesis and amino acid metabolism in the obese mice to the levels of lean mice, whereas rosiglitazone partially normalized levels of enzymes involved in amino acid metabolism. In summary, a classical proteomics approach was successfully used to characterize differences at the hepatic proteome level between lean and obese diabetic mice, to map metabolic pathways affected by treatment, and to discriminate between effects caused by treatment with agonists of the closely related PPAR, and PPAR, receptors. [source] Emodin, a natural product, selectively inhibits 11,-hydroxysteroid dehydrogenase type 1 and ameliorates metabolic disorder in diet-induced obese miceBRITISH JOURNAL OF PHARMACOLOGY, Issue 1 2010Ying Feng BACKGROUND AND PURPOSE 11,-Hydroxysteroid dehydrogenase type 1 (11,-HSD1) is an attractive therapeutic target of type 2 diabetes and metabolic syndrome. Emodin, a natural product and active ingredient of various Chinese herbs, has been demonstrated to possess multiple biological activities. Here, we investigated the effects of emodin on 11,-HSD1 and its ability to ameliorate metabolic disorders in diet-induced obese (DIO) mice. EXPERIMENTAL APPROACH Scintillation proximity assay was performed to evaluate inhibition of emodin against recombinant human and mouse 11,-HSDs. The ability of emodin to inhibit prednisone- or dexamethasone-induced insulin resistance was investigated in C57BL/6J mice and its effect on metabolic abnormalities was observed in DIO mice. KEY RESULTS Emodin is a potent and selective 11,-HSD1 inhibitor with the IC50 of 186 and 86 nM for human and mouse 11,-HSD1, respectively. Single oral administration of emodin inhibited 11,-HSD1 activity of liver and fat significantly in mice. Emodin reversed prednisone-induced insulin resistance in mice, whereas it did not affect dexamethasone-induced insulin resistance, which confirmed its inhibitory effect on 11,-HSD1 in vivo. In DIO mice, oral administration of emodin improved insulin sensitivity and lipid metabolism, and lowered blood glucose and hepatic PEPCK, and glucose-6-phosphatase mRNA. CONCLUSIONS AND IMPLICATIONS This study demonstrated a new role for emodin as a potent and selective inhibitor of 11,-HSD1 and its beneficial effects on metabolic disorders in DIO mice. This highlights the potential value of analogues of emodin as a new class of compounds for the treatment of metabolic syndrome or type 2 diabetes. [source] Pitavastatin inhibits azoxymethane-induced colonic preneoplastic lesions in C57BL/KsJ- db/db obese miceCANCER SCIENCE, Issue 7 2010Yoichi Yasuda Obesity and related metabolic abnormalities are risk factors for colorectal cancer. A state of chronic inflammation and adipocytokine imbalance may play a role in colorectal carcinogenesis. Statins, which are commonly used for the treatment of hyperlipidemia, are known to possess anti-inflammatory effects. Statins also exert chemopreventive properties against various cancers. The present study examined the effects of pitavastatin, a recently developed lipophilic statin, on the development of azoxymethane (AOM)-initiated colonic premalignant lesions in C57BL/KsJ- db/db (db/db) obese mice. Male db/db mice were administrated weekly subcutaneous injections of AOM (15 mg/kg body weight) for 4 weeks and then were subsequently fed a diet containing 1 ppm or 10 ppm pitavastatin for 8 weeks. Feeding with either dose of pitavastatin significantly reduced the number of colonic premalignant lesions, ,-catenin accumulated crypts, by inhibiting proliferation and the surrounding inflammation. Pitavastatin increased the serum levels of adiponectin while conversely decreasing the serum levels of total cholesterol, tumor necrosis factor-, (TNF-,), interleukin (IL)-6, IL-18, and leptin. Pitavastatin also caused a significant increase in the expression of phosphorylated form of the AMP-activated kinase (AMPK) protein on the colonic mucosa of AOM-treated mice. In addition, the expression levels of TNF-,, IL-6, IL-18, and COX-2 mRNAs on the colonic mucosa of AOM-treated mice were decreased by treatment with this agent. These findings suggest that pitavastatin attenuates chronic inflammation and improves the imbalance of adipocytokines, both of which are caused by the presence of excess adipose tissues, thereby preventing the development of colonic premalignancies in an obesity-related colon cancer model. Therefore, some types of statins, including pitavastatin, may be a useful chemoprevention modality for colon cancer in obese individuals. (Cancer Sci 2010) [source] A metabolic syndrome of hypertension, hyperinsulinaemia and hypercholesterolaemia in the New Zealand obese mouseEUROPEAN JOURNAL OF CLINICAL INVESTIGATION, Issue 3 2000Ortlepp Background New Zealand obese (NZO) mice exhibit a polygenic obesity associated with hyperinsulinaemia and hyperglycaemia. Here we show that the strain presents additional features of a metabolic syndrome, i.e. elevated blood pressure, serum cholesterol and serum triglyceride levels. Materials and methods A back-cross model of NZO mice with the lean Swiss Jackson Laboratory (SJL) strain was established in order to investigate further the correlation between hypertension, obesity, serum insulin and hyperglycaemia. Results Systolic blood pressure was significantly elevated at 6 weeks of age and appeared to parallel the weight gain of the animals. Serum insulin levels, presumably reflecting insulin resistance, and systolic blood pressure values were significantly correlated with the body mass index (r2 = 0.707 and 0.486, respectively) in the back-cross mice. In contrast, blood pressure was only weakly correlated with serum insulin (r2 = 0.288) in non-diabetic mice, and was independent of serum insulin levels in diabetic animals. Conclusion The data are consistent with the concept that hypertension and insulin resistance are a characteristic consequence of the genetic constellation leading to obesity in the NZO strain, and that these traits reflect related mechanisms. It appears unlikely, however, that hypertension is a direct consequence of hyperinsulinaemia. [source] | |||||||||||||