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- Hiukka, Anne, et al.
(author)
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Long-term effects of fenofibrate on carotid intima-media thickness and augmentation index in subjects with type 2 diabetes mellitus.
- 2008
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In: Journal of the American College of Cardiology. - : Elsevier BV. - 1558-3597 .- 0735-1097. ; 52:25, s. 2190-7
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Journal article (peer-reviewed)abstract
- OBJECTIVES: The aim of this substudy was to ascertain whether long-term treatment with fenofibrate reduces surrogate measures of atherosclerosis, biomarkers of inflammation, and endothelial activation in patients with type 2 diabetes. BACKGROUND: Some fibrates may decrease cardiovascular events, improve endothelial function, and reduce levels of acute-phase proteins. In the FIELD (Fenofibrate Intervention and Event Lowering in Diabetes) study, fenofibrate failed to decrease the primary end point of coronary events in patients with type 2 diabetes. METHODS: A total of 170 patients with type 2 diabetes of the FIELD Helsinki cohort were randomly assigned to micronized fenofibrate 200 mg/day or placebo in a double-blind design. Carotid intima-media thickness (IMT) and the augmentation index (a measure of large artery stiffness) were measured at baseline and at second- and fifth-year visits. Plasma levels of interleukin (IL)-6, C-reactive protein (CRP), serum amyloid A (SAA), secretory phospholipase A2 IIA (SPLA2), E-selectin, vascular cellular adhesion molecule (VCAM)-1, and intercellular adhesion molecule (CAM)-1 were determined by commercial enzyme-linked immunosorbent assay kits at the same visits. RESULTS: IMT and the augmentation index increased similarly in both treatment groups during the study. Plasma levels of CRP, IL-6, SPLA2, SAA, VCAM-1, ICAM-1, and E-selectin remained unchanged in both groups. CONCLUSIONS: Fenofibrate treatment was not associated with beneficial changes in IMT, augmentation index, or biomarkers of inflammation and endothelial function. (Fenofibrate Intervention and Event Lowering in Diabetes; NCT00132886).
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- Kolak, Maria, et al.
(author)
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Adipose tissue inflammation and increased ceramide content characterize subjects with high liver fat content independent of obesity
- 2007
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In: Diabetes. - : American Diabetes Association. - 0012-1797 .- 1939-327X. ; 56:8, s. 1960-1968
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Journal article (peer-reviewed)abstract
- OBJECTIVE: We sought to determine whether adipose tissue is inflamed in individuals with increased liver fat (LFAT) independently of obesity.RESEARCH DESIGN AND METHODS: A total of 20 nondiabetic, healthy, obese women were divided into normal and high LFAT groups based on their median LFAT level (2.3 +/- 0.3 vs. 14.4 +/- 2.9%). Surgical subcutaneous adipose tissue biopsies were studied using quantitative PCR, immunohistochemistry, and a lipidomics approach to search for putative mediators of insulin resistance and inflammation. The groups were matched for age and BMI. The high LFAT group had increased insulin (P = 0.0025) and lower HDL cholesterol (P = 0.02) concentrations.RESULTS: Expression levels of the macrophage marker CD68, the chemokines monocyte chemoattractant protein-1 and macrophage inflammatory protein-1alpha, and plasminogen activator inhibitor-1 were significantly increased, and those of peroxisome proliferator-activated receptor-gamma and adiponectin decreased in the high LFAT group. CD68 expression correlated with the number of macrophages and crown-like structures (multiple macrophages fused around dead adipocytes). Concentrations of 154 lipid species in adipose tissue revealed several differences between the groups, with the most striking being increased concentrations of triacylglycerols, particularly long chain, and ceramides, specifically Cer(d18:1/24:1) (P = 0.01), in the high LFAT group. Expression of sphingomyelinases SMPD1 and SMPD3 were also significantly increased in the high compared with normal LFAT group.CONCLUSIONS: Adipose tissue is infiltrated with macrophages, and its content of long-chain triacylglycerols and ceramides is increased in subjects with increased LFAT compared with equally obese subjects with normal LFAT content. Ceramides or their metabolites could contribute to adverse effects of long-chain fatty acids on insulin resistance and inflammation.
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- Kotronen, Anna, et al.
(author)
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Hepatic stearoyl-CoA desaturase (SCD)-1 activity and diacylglycerol but not ceramide concentrations are increased in the nonalcoholic human fatty liver
- 2009
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In: Diabetes. - : American Diabetes Association. - 0012-1797 .- 1939-327X. ; 58:1, s. 203-208
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Journal article (peer-reviewed)abstract
- OBJECTIVE: To determine whether 1) hepatic ceramide and diacylglycerol concentrations, 2) SCD1 activity, and 3) hepatic lipogenic index are increased in the human nonalcoholic fatty liver.RESEARCH DESIGN AND METHODS: We studied 16 subjects with (n = 8) and without (n = 8) histologically determined nonalcoholic fatty liver (NAFL(+) and NAFL(-)) matched for age, sex, and BMI. Hepatic concentrations of lipids and fatty acids were quantitated using ultra-performance liquid chromatography coupled to mass spectrometry and gas chromatography.RESULTS: The absolute (nmol/mg) hepatic concentrations of diacylglycerols but not ceramides were increased in the NAFL(+) group compared with the NAFL(-) group. The livers of the NAFL(+) group contained proportionally less long-chain polyunsaturated fatty acids as compared with the NAFL(-) group. Liver fat percent was positively related to hepatic stearoyl-CoA desaturase 1 (SCD1) activity index (r = 0.70, P = 0.003) and the hepatic lipogenic index (r = 0.54, P = 0.030). Hepatic SCD1 activity index was positively related to the concentrations of diacylglycerols (r = 0.71, P = 0.002) but not ceramides (r = 0.07, NS).CONCLUSIONS: We conclude that diacylglycerols but not ceramides are increased in NAFL. The human fatty liver is also characterized by depletion of long polyunsaturated fatty acids in the liver and increases in hepatic SCD1 and lipogenic activities.
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- Pietiläinen, Kirsi H., et al.
(author)
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Acquired obesity is associated with changes in the serum lipidomic profile independent of genetic effects : a monozygotic twin study
- 2007
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In: PLOS ONE. - : PLOS. - 1932-6203. ; 2:2
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Journal article (peer-reviewed)abstract
- Both genetic and environmental factors are involved in the etiology of obesity and the associated lipid disturbances. We determined whether acquired obesity is associated with changes in global serum lipid profiles independent of genetic factors in young adult monozygotic (MZ) twins. 14 healthy MZ pairs discordant for obesity (10 to 25 kg weight difference) and ten weight concordant control pairs aged 24-27 years were identified from a large population-based study. Insulin sensitivity was assessed by the euglycemic clamp technique, and body composition by DEXA (% body fat) and by MRI (subcutaneous and intra-abdominal fat). Global characterization of lipid molecular species in serum was performed by a lipidomics strategy using liquid chromatography coupled to mass spectrometry. Obesity, independent of genetic influences, was primarily related to increases in lysophosphatidylcholines, lipids found in proinflammatory and proatherogenic conditions and to decreases in ether phospholipids, which are known to have antioxidant properties. These lipid changes were associated with insulin resistance, a pathogonomic characteristic of acquired obesity in these young adult twins. Our results show that obesity, already in its early stages and independent of genetic influences, is associated with deleterious alterations in the lipid metabolism known to facilitate atherogenesis, inflammation and insulin resistance.
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- Pietiläinen, Kirsi H., et al.
(author)
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Global transcript profiles of fat in monozygotic twins discordant for BMI : pathways behind acquired obesity
- 2008
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In: PLoS Medicine. - : Public Library of Science (PLoS). - 1549-1277 .- 1549-1676. ; 5:3
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Journal article (peer-reviewed)abstract
- BACKGROUND: The acquired component of complex traits is difficult to dissect in humans. Obesity represents such a trait, in which the metabolic and molecular consequences emerge from complex interactions of genes and environment. With the substantial morbidity associated with obesity, a deeper understanding of the concurrent metabolic changes is of considerable importance. The goal of this study was to investigate this important acquired component and expose obesity-induced changes in biological pathways in an identical genetic background.METHODS AND FINDINGS: We used a special study design of "clonal controls," rare monozygotic twins discordant for obesity identified through a national registry of 2,453 young, healthy twin pairs. A total of 14 pairs were studied (eight male, six female; white), with a mean +/- standard deviation (SD) age 25.8 +/- 1.4 y and a body mass index (BMI) difference 5.2 +/- 1.8 kg/m(2). Sequence analyses of mitochondrial DNA (mtDNA) in subcutaneous fat and peripheral leukocytes revealed no aberrant heteroplasmy between the co-twins. However, mtDNA copy number was reduced by 47% in the obese co-twin's fat. In addition, novel pathway analyses of the adipose tissue transcription profiles exposed significant down-regulation of mitochondrial branched-chain amino acid (BCAA) catabolism (p < 0.0001). In line with this finding, serum levels of insulin secretion-enhancing BCAAs were increased in obese male co-twins (9% increase, p = 0.025). Lending clinical relevance to the findings, in both sexes the observed aberrations in mitochondrial amino acid metabolism pathways in fat correlated closely with liver fat accumulation, insulin resistance, and hyperinsulinemia, early aberrations of acquired obesity in these healthy young adults.CONCLUSIONS: Our findings emphasize a substantial role of mitochondrial energy- and amino acid metabolism in obesity and development of insulin resistance.
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- Sysi-Aho, Marko, et al.
(author)
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Exploring the lipoprotein composition using Bayesian regression on serum lipidomic profiles
- 2007
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In: Bioinformatics. - : Oxford University Press. - 1367-4803 .- 1367-4811 .- 1460-2059. ; 23:13, s. i519-i528
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Journal article (peer-reviewed)abstract
- MOTIVATION: Serum lipids have been traditionally studied in the context of lipoprotein particles. Today's emerging lipidomics technologies afford sensitive detection of individual lipid molecular species, i.e. to a much greater detail than the scale of lipoproteins. However, such global serum lipidomic profiles do not inherently contain any information on where the detected lipid species are coming from. Since it is too laborious and time consuming to routinely perform serum fractionation and lipidomics analysis on each lipoprotein fraction separately, this presents a challenge for the interpretation of lipidomic profile data. An exciting and medically important new bioinformatics challenge today is therefore how to build on extensive knowledge of lipid metabolism at lipoprotein levels in order to develop better models and bioinformatics tools based on high-dimensional lipidomic data becoming available today.RESULTS: We developed a hierarchical Bayesian regression model to study lipidomic profiles in serum and in different lipoprotein classes. As a background data for the model building, we utilized lipidomic data for each of the lipoprotein fractions from 5 subjects with metabolic syndrome and 12 healthy controls. We clustered the lipid profiles and applied a regression model within each cluster separately. We found that the amount of a lipid in serum can be adequately described by the amounts of lipids in the lipoprotein classes. In addition to improved ability to interpret lipidomic data, we expect that our approach will also facilitate dynamic modelling of lipid metabolism at the individual molecular species level.
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