| 1. |
- Ahlin, Sofie, 1985, et al.
(författare)
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No Evidence for a Role of Adipose Tissue-Derived Serum Amyloid A in the Development of Insulin Resistance or Obesity-Related Inflammation in hSAA1(+/)- Transgenic Mice
- 2013
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Ingår i: Plos One. - : Public Library of Science (PLoS). - 1932-6203. ; 8:8
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Tidskriftsartikel (refereegranskat)abstract
- Obesity is associated with a low-grade inflammation including moderately increased serum levels of the acute phase protein serum amyloid A (SAA). In obesity, SAA is mainly produced from adipose tissue and serum levels of SAA are associated with insulin resistance. SAA has been described as a chemoattractant for inflammatory cells and adipose tissue from obese individuals contains increased numbers of macrophages. However, whether adipose tissue-derived SAA can have a direct impact on macrophage infiltration in adipose tissue or the development of insulin resistance is unknown. The aim of this study was to investigate the effects of adipose tissue-derived SAA1 on the development of insulin resistance and obesity-related inflammation. We have previously established a transgenic mouse model expressing human SAA1 in the adipose tissue. For this report, hSAA1(+/-) transgenic mice and wild type mice were fed with a high fat diet or normal chow. Effects of hSAA1 on glucose metabolism were assessed using an oral glucose tolerance test. Real-time PCR was used to measure the mRNA levels of macrophage markers and genes related to insulin sensitivity in adipose tissue. Cytokines during inflammation were analyzed using a Proinflammatory 7-plex Assay. We found similar insulin and glucose levels in hSAA1 mice and wt controls during an oral glucose tolerance test and no decrease in mRNA levels of genes related to insulin sensitivity in adipose tissue in neither male nor female hSAA1 animals. Furthermore, serum levels of proinflammatory cytokines and mRNA levels of macrophage markers in adipose tissue were not increased in hSAA1 mice. Hence, in this model we find no evidence that adipose tissue-derived hSAA1 influences the development of insulin resistance or obesity-related inflammation.
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| 2. |
- Olsson, Maja, 1975, et al.
(författare)
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Establishment of a transgenic mouse model specifically expressing human serum amyloid a in adipose tissue.
- 2011
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Ingår i: PloS one. - : Public Library of Science (PLoS). - 1932-6203. ; 6:5
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Tidskriftsartikel (refereegranskat)abstract
- Obesity and obesity co-morbidities are associated with a low grade inflammation and elevated serum levels of acute phase proteins, including serum amyloid A (SAA). In the non-acute phase in humans, adipocytes are major producers of SAA but the function of adipocyte-derived SAA is unknown. To clarify the role of adipocyte-derived SAA, a transgenic mouse model expressing human SAA1 (hSAA) in adipocytes was established. hSAA expression was analysed using real-time PCR analysis. Male animals were challenged with a high fat (HF) diet. Plasma samples were subjected to fast protein liquid chromatography (FPLC) separation. hSAA, cholesterol and triglyceride content were measured in plasma and in FPLC fractions. Real-time PCR analysis confirmed an adipose tissue-specific hSAA gene expression. Moreover, the hSAA gene expression was not influenced by HF diet. However, hSAA plasma levels in HF fed animals (37.7±4.0 µg/mL, n = 7) were increased compared to those in normal chow fed animals (4.8±0.5 µg/mL, n = 10; p<0.001), and plasma levels in the two groups were in the same ranges as in obese and lean human subjects, respectively. In FPLC separated plasma samples, the concentration of hSAA peaked in high-density lipoprotein (HDL) containing fractions. In addition, cholesterol distribution over the different lipoprotein subfractions as assessed by FPLC analysis was similar within the two experimental groups. The established transgenic mouse model demonstrates that adipose tissue produced hSAA enters the circulation, resulting in elevated plasma levels of hSAA. This new model will enable further studies of metabolic effects of adipose tissue-derived SAA.
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| 3. |
- Saiki, Atsuhito, et al.
(författare)
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Tenomodulin is highly expressed in adipose tissue, increased in obesity, and down-regulated during diet-induced weight loss.
- 2009
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Ingår i: The Journal of clinical endocrinology and metabolism. - : The Endocrine Society. - 1945-7197 .- 0021-972X. ; 94:10, s. 3987-94
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Tidskriftsartikel (refereegranskat)abstract
- CONTEXT: Tenomodulin (TNMD), a putative angiogenesis inhibitor, is expressed in hypovascular connective tissues. Global gene expression scans show that the TNMD gene also is expressed in human adipose tissue and that its expression is regulated in response to weight reduction; however, more detailed information is lacking. OBJECTIVE: The aim of this study was to investigate TNMD tissue distribution and TNMD gene expression in human adipose tissue in relation to obesity and metabolic disease. DESIGN, PATIENTS, AND INTERVENTIONS: TNMD gene expression, tissue distribution, and TNMD gene expression in adipose tissue from different depots, from lean and obese subjects, and during diet-induced weight reduction were analyzed by DNA microarray and real-time PCR. MAIN OUTCOME MEASURE: We primarily measured TNMD gene expression. RESULTS: The TNMD gene was predominantly expressed in sc adipose tissue. TNMD gene expression was higher in sc than omental adipose tissue both in lean (P = 0.002) and obese subjects (P = 0.014). In both women and men, TNMD gene expression was significantly higher in the obese subjects compared to the lean subjects (P = 1.1 x 10(-26) and P = 0.010, respectively). In a multiple linear regression analysis, BMI was a significant independent predictor of TNMD gene expression. TNMD gene expression was down-regulated during diet-induced weight loss, with a 65% decrease after 18 wk of diet (P < 0.0001). CONCLUSIONS: We conclude that human adipose tissue TNMD gene expression is highly affected by obesity, adipose tissue location, and weight loss, indicating that TNMD may play a role in adipose tissue function.
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| 4. |
- Ahlin, Sofie, 1985, et al.
(författare)
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Macrophage Gene Expression in Adipose Tissue is Associated with Insulin Sensitivity and Serum Lipid Levels Independent of Obesity.
- 2013
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Ingår i: Obesity (Silver Spring, Md.). - : Wiley. - 1930-739X .- 1930-7381. ; 21:12
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Tidskriftsartikel (refereegranskat)abstract
- Objective: Obesity is linked to both increased metabolic disturbances and increased adipose tissue macrophage infiltration. However, whether macrophage infiltration directly influences human metabolism is unclear. The aim of this study was to investigate if there are obesity-independent links between adipose tissue macrophages and metabolic disturbances. Design and Methods: Expression of macrophage markers in adipose tissue was analyzed by DNA microarrays in the SOS Sib Pair study and in patients with type 2 diabetes and a BMI-matched healthy control group. Results: The expression of macrophage markers in adipose tissue was increased in obesity and associated with several metabolic and anthropometric measurements. After adjustment for BMI, the expression remained associated with insulin sensitivity, serum levels of insulin, C-peptide, high density lipoprotein cholesterol (HDL-cholesterol) and triglycerides. In addition, the expression of most macrophage markers was significantly increased in patients with type 2 diabetes compared to the control group. Conclusion: Our study shows that infiltration of macrophages in human adipose tissue, estimated by the expression of macrophage markers, is increased in subjects with obesity and diabetes and associated with insulin sensitivity and serum lipid levels independent of BMI. This indicates that adipose tissue macrophages may contribute to the development of insulin resistance and dyslipidemia.
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| 5. |
- Olofsson, Louise, 1977, et al.
(författare)
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CCAAT/enhancer binding protein alpha (C/EBPalpha) in adipose tissue regulates genes in lipid and glucose metabolism and a genetic variation in C/EBPalpha is associated with serum levels of triglycerides.
- 2008
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Ingår i: The Journal of clinical endocrinology and metabolism. - : The Endocrine Society. - 0021-972X .- 1945-7197. ; 93:12, s. 4880-6
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Tidskriftsartikel (refereegranskat)abstract
- CONTEXT: CCAAT/enhancer binding protein alpha (C/EBPalpha) is a transcription factor involved in adipogenesis and hepatic glucose and lipid metabolism. OBJECTIVE: The aim of the study was to test the hypothesis that adipose tissue C/EBPalpha regulates genes in lipid and glucose metabolism and to test for an association between a polymorphism in C/EBPalpha and metabolic parameters. DESIGN AND METHODS: Adipose tissue C/EBPalpha mRNA expression was analyzed at four time points in obese subjects with (n = 12) and without (n = 12) the metabolic syndrome during caloric restriction (450 kcal/d for 16 wk) using DNA microarray and real-time PCR. Adenoviral overexpression of C/EBPalpha was used to identify genes regulated by C/EBPalpha in 3T3-L1 cells. Association between a genetic variation in C/EBPalpha (rs12691) and metabolic parameters was tested in the Swedish Obese Subjects (SOS) study (n = 528) and replicated in Finnish individuals from the Botnia type 2 diabetes study (n = 4,866). RESULTS: During caloric restriction, adipose tissue C/EBPalpha mRNA levels were reduced in subjects with the metabolic syndrome (P = 0.024) and correlated to metabolic parameters. In 3T3-L1 cells, C/EBPalpha regulated the expression of adiponectin; hexokinase 2; lipoprotein lipase; diacylglycerol O-acyltransferase 1 and 2; ATP-binding cassette, sub-family D, member 2; acyl-coenzyme A synthetase long-chain family member 1; CD36; and hydroxysteroid 11-beta dehydrogenase 1. Furthermore, the expression of the human homologs, except adiponectin, correlated to C/EBPalpha mRNA levels in human adipose tissue. The AA genotype of rs12691 was associated with higher serum triglyceride levels in the SOS study (P = 0.022), and this association was replicated in the Botnia study (P = 0.041). CONCLUSIONS: Adipose tissue C/EBPalpha regulates several genes in glucose and lipid metabolism, and a genetic variation in C/EBPalpha is associated with triglycerides in two independent populations.
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| 6. |
- Olsson, Maja, 1975, et al.
(författare)
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Expression of the selenoprotein S (SELS) gene in subcutaneous adipose tissue and SELS genotype are associated with metabolic risk factors.
- 2011
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Ingår i: Metabolism: clinical and experimental. - : Elsevier BV. - 1532-8600. ; 60:1, s. 114-20
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Tidskriftsartikel (refereegranskat)abstract
- The selenoprotein S (SELS) is a putative receptor for serum amyloid A, and recent studies have suggested that SELS may be a link between type 2 diabetes mellitus and inflammation. Genetic studies of SELS polymorphisms have revealed associations with circulating levels of inflammatory markers and hard end points of cardiovascular disease. In this study, we analyzed SELS expression in subcutaneous adipose tissue and SELS genotype in relation to metabolic risk factors. DNA microarray expression analysis was used to study the expression of SELS in lean and obese siblings from the Swedish Obese Subjects Sib Pair Study. TaqMan genotyping was used to analyze 3 polymorphisms, previously found to be associated with circulating levels of inflammatory markers, in the INTERGENE case-control study of myocardial infarction and unstable angina pectoris. Possible associations between SELS genotype and/or expression with anthropometry and measures of metabolic status were investigated. Real-time polymerase chain reaction was used to analyze the SELS expression in isolated human adipocytes incubated with insulin. In lean subjects, we found correlations between SELS gene expression in subcutaneous adipose tissue and measures of obesity (waist, P = .045; sagittal diameter, P = .031) and blood pressure (diastolic, P = .016; systolic P = .015); and in obese subjects, we found correlations with measures of obesity (body mass index, P = .03; sagittal diameter, P = .008) and glycemic control (homeostasis model assessment of insulin resistance, P = .011; insulin, P = .009) after adjusting for age and sex. The 5227GG genotype was associated with serum levels of insulin (P = .006) and homeostasis model assessment of insulin resistance (P = .007). The expression of SELS increased after insulin stimulation in isolated human adipocytes (P = .008). In this study, we found an association between both SELS gene expression in adipose tissue and SELS genotype with measures of glycemic control. In vitro studies demonstrated that the SELS gene is regulated by insulin in human subcutaneous adipocytes. This study further supports a role for SELS in the development of metabolic disease, especially in the context of insulin resistance.
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| 7. |
- Jernås, Margareta, 1961, et al.
(författare)
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Changes in adipose tissue gene expression and plasma levels of adipokines and acute-phase proteins in patients with critical illness.
- 2009
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Ingår i: Metabolism: clinical and experimental. - : Elsevier BV. - 1532-8600. ; 58:1, s. 102-8
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Tidskriftsartikel (refereegranskat)abstract
- Insulin resistance develops rapidly during critical illness. The release of adipokines from adipose tissue is thought to play a key role in the development of insulin resistance, as are elevated levels of acute-phase proteins. The aim of this study was to identify changes in adipose tissue gene expression and plasma levels of adipokines and acute-phase proteins during critical illness. From 8 patients with subarachnoidal hemorrhage, consecutive blood samples and adipose tissue biopsies were obtained at 3 time points, twice during intensive care (1-2 days [IC1] and 7-9 days after subarachnoidal hemorrhage) and once after 8 months (recovery). The patients received a continuous insulin infusion to maintain normal glucose levels reflecting insulin resistance. The DNA microarray analysis showed increased zink-alpha2 glycoprotein (ZAG) and phospholipase A2, group IIA messenger RNA levels during intensive care compared with recovery (P < .05). Real-time polymerase chain reaction confirmed the increased expression of ZAG and phospholipase A2, group IIA. Plasma levels of ZAG, serum amyloid A, and C-reactive protein were higher at 7 to 9 days after subarachnoidal hemorrhage compared with either IC1 or recovery (P = .0001); and plasma levels of retinol-binding protein 4 and adiponectin were lower at IC1 compared with recovery (P = .05). The described changes in adipose tissue gene expression and plasma levels of adipokines and acute-phase proteins may influence the development of insulin resistance during critical illness.
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| 8. |
- Olofsson, Louise, 1977, et al.
(författare)
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Preliminary report: Zn-alpha2-glycoprotein genotype and serum levels are associated with serum lipids.
- 2010
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Ingår i: Metabolism. - : Elsevier BV. - 1532-8600 .- 0026-0495. ; 59:9, s. 1316-1318
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Tidskriftsartikel (refereegranskat)abstract
- Zn-alpha2-glycoprotein (ZAG) is a serum protein implicated in cancer cachexia and lipolysis. Our aim was to investigate serum levels of ZAG and polymorphisms in the ZAG gene in relation to serum lipids in man. Serum levels of ZAG correlated with serum levels of cholesterol (P = .00088) in healthy subjects and during weight loss (P = .059). The ZAG genotype was associated with total cholesterol (P = .014) and low-density lipoprotein cholesterol (P = .026) in healthy subjects, and the associations were replicated in an additional cohort (P = .0017 and P = .060, respectively). Our data indicate that ZAG plays a role in lipid metabolism.
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