| 1. |
- Aminoff, A, et al.
(författare)
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Allele-specific regulation of MTTP expression influences the risk of ischemic heart disease.
- 2010
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Ingår i: Journal of lipid research. - 0022-2275 .- 1539-7262. ; 51:1, s. 103-11
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Tidskriftsartikel (refereegranskat)abstract
- Promoter polymorphisms in microsomal triglyceride transfer protein (MTTP) have been associated with decreased plasma lipids but an increased risk for ischemic heart disease (IHD), indicating that MTTP influences the susceptibility for IHD independent of plasma lipids. The objective of this study was to characterize the functional promoter polymorphism in MTTP predisposing to IHD and its underlying mechanism. Use of pyrosequencing technology revealed that presence of the minor alleles of the promoter polymorphisms -493G>T and -164T>C result in lower transcription of MTTP in vivo in the heart, liver, and macrophages. In vitro experiments indicated that the minor -164C allele mediates the lower gene expression and that C/EBP binds to the polymorphic region in an allele-specific manner. Furthermore, homozygous carriers of the -164C were found to have increased risk for IHD as shown in a case-control study including a total of 544 IHD patients and 544 healthy control subjects. We concluded that carriers of the minor -164C allele have lower expression of MTTP in the heart, mediated at least partly by the transcription factor CCAAT/enhancer binding protein, and that reduced concentration of MTTP in the myocardium may contribute to IHD upon ischemic damage.
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| 2. |
- Bunck, Mathijs C, et al.
(författare)
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Effects of Exenatide on Measures of {beta}-Cell Function After 3 Years in Metformin-Treated Patients With Type 2 Diabetes.
- 2011
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Ingår i: Diabetes care. - : American Diabetes Association. - 1935-5548 .- 0149-5992. ; 34:9, s. 2041-2047
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE We previously showed that exenatide (EXE) enhanced insulin secretion after 1 year of treatment, relative to insulin glargine (GLAR), with a similar glucose-lowering action. These effects were not sustained after a 4-week off-drug period. This article reports the results after additional 2 years of exposure. RESEARCH DESIGN AND METHODS Sixty-nine metformin-treated patients with type 2 diabetes were randomized to EXE or GLAR. Forty-six patients entered the 2-year extension study in which they continued their allocated therapy. Thirty-six completed (EXE: n = 16; GLAR: n = 20) the 3-year exposure period. Insulin sensitivity (M value) and β-cell function were measured by euglycemic hyperinsulinemic clamp followed by hyperglycemic clamp with arginine stimulation at pretreatment (week 52) and 4 weeks after discontinuation of study medication (week 56 and week 172). First-phase glucose stimulated C-peptide secretion was adjusted for M value and calculated as the disposition index (DI). RESULTS At 3 years, EXE and GLAR resulted in similar levels of glycemic control: 6.6 ± 0.2% and 6.9 ± 0.2%, respectively (P = 0.186). EXE compared with GLAR significantly reduced body weight (-7.9 ± 1.8 kg; P < 0.001). After the 4-week off-drug period, EXE increased the M value by 39% (P = 0.006) while GLAR had no effect (P = 0.647). Following the 4-week off-drug period, the DI, compared with pretreatment, increased with EXE, but decreased with GLAR (1.43 ± 0.78 and -0.99 ± 0.65, respectively; P = 0.028). CONCLUSIONS EXE and GLAR sustained HbA(1c) over the 3-year treatment period, while EXE reduced body weight and GLAR increased body weight. Following the 3-year treatment with EXE, the DI was sustained after a 4-week off-drug period. These findings suggest a beneficial effect on β-cell health.
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| 3. |
- Bunck, M. C., et al.
(författare)
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Exenatide affected circulating cardiovascular risk biomarkers independently of changes in body composition
- 2010
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Ingår i: Diabetes Care. - 0149-5992. ; 33:8, s. 1734-1737
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE To study the effect of exenatide on body composition and circulating cardiovascular risk biomarkers. RESEARCH DESIGN AND METHODS Metformin-treated patients with type 2 diabetes (N = 69) were randomized to exenatide or insulin glargine and treated for 1 year. Body composition was evaluated by dual-energy X-ray absorptiometry. Additionally, body weight, waist circumference, and cardiovascular biomarkers were measured. RESULTS Treatment with exenatide for 1 year significantly reduced body weight, waist circumference, and total body and trunkal fat mass by 6, 5, 11, and 13%, respectively. In addition, exenatide increased total adiponectin by 12% and reduced high-sensitivity C-reactive protein by 61%. Insulin glargine significantly reduced endothelin-1 by 7%. These changes were statistically independent of the change in total body fat mass and body weight. CONCLUSIONS Exenatide treatment for 1 year reduced body fat mass and improved the profile of circulating biomarkers of cardiovascular risk. No significant changes were seen with insulin glargine except a trend for reduced endothelin-1 levels.
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| 4. |
- Bunck, Mathijs C, et al.
(författare)
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One-year treatment with exenatide vs. insulin glargine: effects on postprandial glycemia, lipid profiles, and oxidative stress.
- 2010
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Ingår i: Atherosclerosis. - : Elsevier BV. - 1879-1484 .- 0021-9150. ; 212:1, s. 223-9
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: The objective of the present study was to investigate the effects of one-year treatment with exenatide or Insulin Glargine, followed by a 5-week off-drug period, on postprandial lipidaemia, glycaemia and measures of oxidative stress. METHODS: Sixty-nine metformin-treated patients with type 2 diabetes were randomised (using apermuted block randomisation scheme stratified by site and baseline HbA(1c) stratum (< or = 8.5% or >8.5%) of which 60 completed (exenatide n=30; Insulin Glargine n=30) the pre-treatment and on-drug meal test. Postprandial glucose, lipids and lipoproteins, and oxidative stress markers were studied at week -1, 51, and after a 5-week off-drug period following a breakfast and lunch mixed-meal containing 50 g fat, 75 g carbohydrates, and 35 g protein. RESULTS: 51-Week exenatide treatment resulted in a significant reduction of prandial glucose, triglycerides, apo-B48, calculated VLDL-C, FFA and MDA excursions whereas Insulin Glargine predominantly reduced fasting glucose, FFA and MDA. Changes in markers of oxidative stress were related to changes in postprandial glucose and triglyceride excursions, independent of treatment arm. All postprandial measures returned to pre-treatment values in both groups after 5-week cessation of study treatment. CONCLUSION: Exenatide showed beneficial effects on postprandial glycaemia and lipidaemia, and these effects were related to changes in the oxidative stress markers MDA and oxLDL during one year of treatment as compared to Insulin Glargine. Following cessation of both exenatide and Insulin Glargine measures returned to pre-treatment values, suggesting that ongoing treatment is necessary to maintain the beneficial effects of either therapy.
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| 5. |
- Hyysalo, Jenni, et al.
(författare)
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A population-based study on the prevalence of NASH using scores validated against liver histology.
- 2014
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Ingår i: Journal of Hepatology. - : Elsevier BV. - 0168-8278. ; 60:4, s. 839-846
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Tidskriftsartikel (refereegranskat)abstract
- Non-alcoholic steatohepatitis (NASH) is a leading cause of chronic liver disease in Western countries. Diagnosis of NASH requires a liver biopsy. We estimated the prevalence of NASH non-invasively in a population-based study using scores validated against liver histology.
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| 6. |
- Hyysalo, Jenni, et al.
(författare)
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Circulating triacylglycerol signatures in nonalcoholic fatty liver disease associated with the I148M variant in PNPLA3 and with obesity
- 2014
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Ingår i: Diabetes. - : American Diabetes Association. - 0012-1797 .- 1939-327X. ; 63:1, s. 312-322
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Tidskriftsartikel (refereegranskat)abstract
- We examined whether relative concentrations of circulating triacylglycerols (TAGs) between carriers compared with noncarriers of PNPLA3(I148M) gene variant display deficiency of TAGs, which accumulate in the liver because of defective lipase activity. We also analyzed the effects of obesity-associated nonalcoholic fatty liver disease (NAFLD) independent of genotype, and of NAFLD due to either PNPLA3(I148M) gene variant or obesity on circulating TAGs. A total of 372 subjects were divided into groups based on PNPLA3 genotype or obesity. Absolute and relative deficiency of distinct circulating TAGs was observed in the PNPLA3(148MM/148MI) compared with the PNPLA3(148II) group. Obese and 'nonobese' groups had similar PNPLA3 genotypes, but the obese subjects were insulin-resistant. Liver fat was similarly increased in obese and PNPLA3(148MM/148MI) groups. Relative concentrations of TAGs in the obese subjects versus nonobese displayed multiple changes. These closely resembled those between obese subjects with NAFLD but without PNPLA3(I148M) versus those with the I148M variant and NAFLD. The etiology of NAFLD influences circulating TAG profiles. 'PNPLA3 NAFLD' is associated with a relative deficiency of TAGs, supporting the idea that the I148M variant impedes intrahepatocellular lipolysis rather than stimulates TAG synthesis. 'Obese NAFLD' is associated with multiple changes in TAGs, which can be attributed to obesity/insulin resistance rather than increased liver fat content per se.
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| 7. |
- Hyötyläinen, Tuulia, 1971-, et al.
(författare)
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Metabolomic analysis of polar metabolites in lipoprotein fractions identifies lipoprotein-specific metabolic profiles and their association with insulin resistance
- 2012
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Ingår i: Molecular Biosystems. - : Royal Society of Chemistry. - 1742-206X .- 1742-2051. ; 8:10, s. 2559-2565
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Tidskriftsartikel (refereegranskat)abstract
- While the molecular lipid composition of lipoproteins has been investigated in detail, little is known about associations of small polar metabolites with specific lipoproteins. The aim of the present study was to investigate the profiles of polar metabolites in different lipoprotein fractions, i.e., very-low-density lipoprotein (VLDL), intermediate-density lipoprotein (IDL), low-density lipoprotein (LDL) and two sub-fractions of the high-density lipoprotein (HDL). The VLDL, IDL, LDL, HDL(2), and HDL(3) fractions were isolated from serum of sixteen individuals having a broad range of insulin sensitivity and characterized using comprehensive two-dimensional gas chromatography combined with time-of-flight mass spectrometry (GC×GC-TOFMS). The lipoprotein fractions had clearly different metabolite profiles, which correlated with the particle size and surface charge. Lipoprotein-specific associations of individual metabolites with insulin resistance were identified, particularly in VLDL and IDL fractions, even in the absence of such associations in serum. The results indicate that the polar molecules are strongly attached to the surface of the lipoproteins. Furthermore, strong lipoprotein-specific associations of metabolites with insulin resistance, as compared to their serum profiles, indicate that lipoproteins may be a rich source of tissue-specific metabolic biomarkers.
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| 8. |
- Kolak, Maria, et al.
(författare)
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Expression of ceramide-metabolising enzymes in subcutaneous and intra-abdominal human adipose tissue
- 2012
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Ingår i: Lipids in Health and Disease. - : BioMed Central (BMC). - 1476-511X. ; 11
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Inflammation and increased ceramide concentrations characterise adipose tissue of obese women with high liver fat content compared to equally obese women with normal liver fat content. The present study characterises enzymes involved in ceramide metabolism in subcutaneous and intra-abdominal adipose tissue.METHODS: Pathways leading to increased ceramide concentrations in inflamed versus non-inflamed adipose tissue were investigated by quantifying expression levels of key enzymes involved in ceramide metabolism. Sphingomyelinases (sphingomyelin phosphodiesterases SMPD1-3) were investigated further using immunohistochemistry to establish their location within adipose tissue, and their mRNA expression levels were determined in subcutaneous and intra-abdominal adipose tissue from both non-obese and obese subject.RESULTS: Gene expression levels of sphingomyelinases, enzymes that hydrolyse sphingomyelin to ceramide, rather than enzymes involved in de novo ceramide synthesis, were higher in inflamed compared to non-inflamed adipose tissue of obese women (with high and normal liver fat contents respectively). Sphingomyelinases were localised to both macrophages and adipocytes, but also to blood vessels and to extracellular regions surrounding vessels within adipose tissue. Expression levels of SMPD3 mRNA correlated significantly with concentrations of different ceramides and sphingomyelins. In both non-obese and obese subjects SMPD3 mRNA levels were higher in the more inflamed intra-abdominal compared to the subcutaneous adipose tissue depot.CONCLUSIONS: Generation of ceramides within adipose tissue as a result of sphingomyelinase action may contribute to inflammation in human adipose tissue.
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| 9. |
- Kotronen, Anna, et al.
(författare)
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Comparison of lipid and fatty acid composition of the liver, subcutaneous and intra-abdominal adipose tissue, and serum
- 2010
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Ingår i: Obesity. - : Wiley-Blackwell Publishing Inc.. - 1930-7381 .- 1930-739X. ; 18:5, s. 937-944
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Tidskriftsartikel (refereegranskat)abstract
- Ceramides may mediate saturated fat-induced insulin resistance, but there are no data comparing ceramide concentrations between human tissues. We therefore performed lipidomic analysis of human subcutaneous (SCfat) and intra-abdominal (IAfat) adipose tissue, the liver, and serum in eight subjects. The liver contained (nmol/mg tissue) significantly more ceramides (1.5-3-fold), sphingomyelins (7-8-fold), phosphatidylethanolamines (10-11-fold), lysophosphatidylcholines (7-12-fold), less ether-linked phosphatidylcholines (2-2.5-fold) but similar amounts of diacylglycerols as compared to SCfat and IAfat. The amounts of ceramides and their synthetic precursors, such as palmitic (16:0) free fatty acids and sphingomyelins, differed considerably between the tissues. The liver contained proportionally more palmitic, stearic (18:0), and long polyunsaturated fatty acids than adipose tissues. Stearoyl-CoA desaturase 1 (SCD1) activity reflected by serum, estimated from the 16:1/16:0-ratio, was closely related to that in the liver (r = 0.86, P = 0.024) but not adipose tissues. This was also true for estimated elongase (18:1/16:1, r = 0.89, P = 0.01), and Delta5 (20:4/20:3, r = 0.89, P = 0.012) and Delta6 (18:3[n-6]/18:2, r = 1.0, P < 0.001) desaturase activities. We conclude that the human liver contains higher concentrations of ceramides and saturated free fatty acids than either SCfat or IAfat.
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| 10. |
- Orešič, Matej, 1967-, et al.
(författare)
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Prediction of non-alcoholic fatty-liver disease and liver fat content by serum molecular lipids
- 2013
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Ingår i: Diabetologia. - : Springer. - 0012-186X .- 1432-0428. ; 56:10, s. 2266-2274
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Tidskriftsartikel (refereegranskat)abstract
- AIMS/HYPOTHESIS: We examined whether analysis of lipids by ultra-performance liquid chromatography (UPLC) coupled to MS allows the development of a laboratory test for non-alcoholic fatty-liver disease (NAFLD), and how a lipid-profile biomarker compares with the prediction of NAFLD and liver-fat content based on routinely available clinical and laboratory data.METHODS: We analysed the concentrations of molecular lipids by UPLC-MS in blood samples of 679 well-characterised individuals in whom liver-fat content was measured using proton magnetic resonance spectroscopy ((1)H-MRS) or liver biopsy. The participants were divided into biomarker-discovery (n = 287) and validation (n = 392) groups to build and validate the diagnostic models, respectively.RESULTS: Individuals with NAFLD had increased triacylglycerols with low carbon number and double-bond content while lysophosphatidylcholines and ether phospholipids were diminished in those with NAFLD. A serum-lipid signature comprising three molecular lipids ('lipid triplet') was developed to estimate the percentage of liver fat. It had a sensitivity of 69.1% and specificity of 73.8% when applied for diagnosis of NAFLD in the validation series. The usefulness of the lipid triplet was demonstrated in a weight-loss intervention study.CONCLUSIONS/INTERPRETATION: The liver-fat-biomarker signature based on molecular lipids may provide a non-invasive tool to diagnose NAFLD, in addition to highlighting lipid molecular pathways involved in the disease.
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