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12. |
- Yaghootkar, Hanieh, et al.
(author)
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Genetic evidence for a normal-weight "metabolically obese" phenotype linking insulin resistance, hypertension, coronary artery disease and type 2 diabetes.
- 2014
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In: Diabetes. - : American Diabetes Association. - 1939-327X .- 0012-1797. ; 63:12, s. 4369-77
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Journal article (peer-reviewed)abstract
- The mechanisms that predispose to hypertension, coronary artery disease (CAD) and type 2 diabetes (T2D) in individuals of normal weight are poorly understood. In contrast, in monogenic primary lipodystrophy - a reduction in subcutaneous adipose tissue - it is clear that it is adipose dysfunction that causes severe insulin resistance (IR), hypertension, coronary artery disease and type 2 diabetes. We aimed to test the hypothesis that common alleles associated with insulin resistance also influence the wider clinical and biochemical profile of monogenic insulin resistance. We selected 19 common genetic variants associated with fasting insulin based measures of insulin resistance. We used hierarchical clustering and results from genome wide association studies of 8 non-disease outcomes of monogenic insulin resistance, to group these variants. We analysed genetic risk scores against disease outcomes including 12,171 T2D cases, 40,365 CAD cases and 69,828 individuals with blood pressure measurements. Hierarchical clustering identified 11 variants associated with a metabolic profile consistent with a common, subtle, form of lipodystrophy. A genetic risk score consisting of these 11 IR risk alleles was associated with higher triglycerides (ß=0.018; p=4x10(-29)), lower HDL cholesterol (ß=-0.020; p=7x10(-37)), greater hepatic steatosis (ß=0.021; p=3x10(-4)) higher alanine transaminase (ß=0.002; p=3x10(-5)), lower SHBG (ß=-0.010; p=9x10(-13)) and lower adiponectin (ß=-0.015; p=2x10(-26)). The same risk alleles were associated with lower BMI (per-allele ß=-0.008; p=7x10(-8)), and increased visceral-to-subcutaneous adipose tissue ratio (ß=-0.015; p=6x10(-7)). Individuals carrying >= 17 fasting insulin raising alleles (5.5% population) were slimmer (0.30 kgm(-2)) but at increased risk of T2D (odds ratio [OR] 1.46, per-allele p=5x10(-13)), CAD (OR 1.12, per-allele p=1x10(-5)), and increased blood pressure (systolic and diastolic blood pressure of 1.21 mmHg (per-allele p=2x10(-5)), and 0.67 mmHg (per-allele p=2x10(-4)), respectively, compared to individuals carrying <=9 risk alleles (5.5% population). Our results provide genetic evidence for a link between the three diseases of the "metabolic syndrome" and point to reduced subcutaneous adiposity as a central mechanism.
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13. |
- Andõn, F. T., et al.
(author)
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Biodegradation of Single-Walled Carbon Nanotubes by Eosinophil Peroxidase
- 2013
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In: Small. - : Wiley-VCH Verlagsgesellschaft. - 1613-6810 .- 1613-6829. ; 9:16, s. 2721-2729
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Journal article (peer-reviewed)abstract
- Eosinophil peroxidase (EPO) is one of the major oxidant-producing enzymes during inflammatory states in the human lung. The degradation of single-walled carbon nanotubes (SWCNTs) upon incubation with human EPO and H2O 2 is reported. Biodegradation of SWCNTs is higher in the presence of NaBr, but neither EPO alone nor H2O2 alone caused the degradation of nanotubes. Molecular modeling reveals two binding sites for SWCNTs on EPO, one located at the proximal side (same side as the catalytic site) and the other on the distal side of EPO. The oxidized groups on SWCNTs in both cases are stabilized by electrostatic interactions with positively charged residues. Biodegradation of SWCNTs can also be executed in an ex vivo culture system using primary murine eosinophils stimulated to undergo degranulation. Biodegradation is proven by a range of methods including transmission electron microscopy, UV-visible-NIR spectroscopy, Raman spectroscopy, and confocal Raman imaging. Thus, human EPO (in vitro) and ex vivo activated eosinophils mediate biodegradation of SWCNTs: an observation that is relevant to pulmonary responses to these materials. Human eosinophil peroxidase (EPO) is able to degrade SWCNTs in vitro in the presence of H2O2. EPO is one of the major oxidant-generating enzymes present in human lungs during inflammatory states. The biodegradation of SWCNTs is evidenced also in an ex vivo culture system using primary murine eosinophils stimulated to undergo degranulation. These results are relevant to potential respiratory exposure to carbon nanotubes.
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15. |
- Kilpeläinen, Tuomas O, et al.
(author)
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Genetic variation near IRS1 associates with reduced adiposity and an impaired metabolic profile.
- 2011
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In: Nature genetics. - : Springer Science and Business Media LLC. - 1546-1718 .- 1061-4036. ; 43:8, s. 753-60
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Journal article (peer-reviewed)abstract
- Genome-wide association studies have identified 32 loci influencing body mass index, but this measure does not distinguish lean from fat mass. To identify adiposity loci, we meta-analyzed associations between ∼2.5 million SNPs and body fat percentage from 36,626 individuals and followed up the 14 most significant (P < 10(-6)) independent loci in 39,576 individuals. We confirmed a previously established adiposity locus in FTO (P = 3 × 10(-26)) and identified two new loci associated with body fat percentage, one near IRS1 (P = 4 × 10(-11)) and one near SPRY2 (P = 3 × 10(-8)). Both loci contain genes with potential links to adipocyte physiology. Notably, the body-fat-decreasing allele near IRS1 is associated with decreased IRS1 expression and with an impaired metabolic profile, including an increased visceral to subcutaneous fat ratio, insulin resistance, dyslipidemia, risk of diabetes and coronary artery disease and decreased adiponectin levels. Our findings provide new insights into adiposity and insulin resistance.
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16. |
- O'Seaghdha, Conall M., et al.
(author)
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Meta-Analysis of Genome-Wide Association Studies Identifies Six New Loci for Serum Calcium Concentrations
- 2013
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In: PLOS Genetics. - : Public Library of Science (PLoS). - 1553-7390 .- 1553-7404. ; 9:9, s. e1003796-
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Journal article (peer-reviewed)abstract
- Calcium is vital to the normal functioning of multiple organ systems and its serum concentration is tightly regulated. Apart from CASR, the genes associated with serum calcium are largely unknown. We conducted a genome-wide association meta-analysis of 39,400 individuals from 17 population-based cohorts and investigated the 14 most strongly associated loci in <= 21,679 additional individuals. Seven loci (six new regions) in association with serum calcium were identified and replicated. Rs1570669 near CYP24A1 (P = 9.1E-12), rs10491003 upstream of GATA3 (P = 4.8E-09) and rs7481584 in CARS (P = 1.2E-10) implicate regions involved in Mendelian calcemic disorders: Rs1550532 in DGKD (P = 8.2E-11), also associated with bone density, and rs7336933 near DGKH/KIAA0564 (P = 9.1E-10) are near genes that encode distinct isoforms of diacylglycerol kinase. Rs780094 is in GCKR. We characterized the expression of these genes in gut, kidney, and bone, and demonstrate modulation of gene expression in bone in response to dietary calcium in mice. Our results shed new light on the genetics of calcium homeostasis.
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17. |
- Sarwar, Nadeem, et al.
(author)
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Interleukin-6 receptor pathways in coronary heart disease : a collaborative meta-analysis of 82 studies
- 2012
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In: The Lancet. - New York, NY, USA : Elsevier. - 0140-6736 .- 1474-547X. ; 379:9822, s. 1205-1213
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Journal article (peer-reviewed)abstract
- Background: Persistent inflammation has been proposed to contribute to various stages in the pathogenesis of cardiovascular disease. Interleukin-6 receptor (IL6R) signalling propagates downstream inflammation cascades. To assess whether this pathway is causally relevant to coronary heart disease, we studied a functional genetic variant known to affect IL6R signalling. Methods: In a collaborative meta-analysis, we studied Asp358Ala (rs2228145) in IL6R in relation to a panel of conventional risk factors and inflammation biomarkers in 125 222 participants. We also compared the frequency of Asp358Ala in 51 441 patients with coronary heart disease and in 136 226 controls. To gain insight into possible mechanisms, we assessed Asp358Ala in relation to localised gene expression and to postlipopolysaccharide stimulation of interleukin 6. Findings: The minor allele frequency of Asp358Ala was 39%. Asp358Ala was not associated with lipid concentrations, blood pressure, adiposity, dysglycaemia, or smoking (p value for association per minor allele >= 0.04 for each). By contrast, for every copy of 358Ala inherited, mean concentration of IL6R increased by 34.3% (95% CI 30.4-38.2) and of interleukin 6 by 14.6% (10.7-18.4), and mean concentration of C-reactive protein was reduced by 7.5% (5.9-9.1) and of fibrinogen by 1.0% (0.7-1.3). For every copy of 358Ala inherited, risk of coronary heart disease was reduced by 3.4% (1.8-5.0). Asp358Ala was not related to IL6R mRNA levels or interleukin-6 production in monocytes. Interpretation: Large-scale human genetic and biomarker data are consistent with a causal association between IL6R-related pathways and coronary heart disease.
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19. |
- Flannick, Jason, et al.
(author)
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Loss-of-function mutations in SLC30A8 protect against type 2 diabetes.
- 2014
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In: Nature Genetics. - : Springer Science and Business Media LLC. - 1546-1718 .- 1061-4036. ; 46:4, s. 357-357
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Journal article (peer-reviewed)abstract
- Loss-of-function mutations protective against human disease provide in vivo validation of therapeutic targets, but none have yet been described for type 2 diabetes (T2D). Through sequencing or genotyping of ∼150,000 individuals across 5 ancestry groups, we identified 12 rare protein-truncating variants in SLC30A8, which encodes an islet zinc transporter (ZnT8) and harbors a common variant (p.Trp325Arg) associated with T2D risk and glucose and proinsulin levels. Collectively, carriers of protein-truncating variants had 65% reduced T2D risk (P = 1.7 × 10(-6)), and non-diabetic Icelandic carriers of a frameshift variant (p.Lys34Serfs*50) demonstrated reduced glucose levels (-0.17 s.d., P = 4.6 × 10(-4)). The two most common protein-truncating variants (p.Arg138* and p.Lys34Serfs*50) individually associate with T2D protection and encode unstable ZnT8 proteins. Previous functional study of SLC30A8 suggested that reduced zinc transport increases T2D risk, and phenotypic heterogeneity was observed in mouse Slc30a8 knockouts. In contrast, loss-of-function mutations in humans provide strong evidence that SLC30A8 haploinsufficiency protects against T2D, suggesting ZnT8 inhibition as a therapeutic strategy in T2D prevention.
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20. |
- Jander, Nikolaus, et al.
(author)
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Indexing aortic valve area by body surface area increases the prevalence of severe aortic stenosis
- 2014
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In: Heart. - : BMJ. - 1355-6037 .- 1468-201X. ; 100:1, s. 28-33
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Journal article (peer-reviewed)abstract
- Background To account for differences in body size in patients with aortic stenosis, aortic valve area (AVA) is divided by body surface area (BSA) to calculate indexed AVA (AVA(index)). Cut-off values for severe stenosis are <1.0cm(2) for AVA and <0.6cm(2)/m(2) for AVA(index). Objective To investigate the influence of indexation on the prevalence of severe aortic stenosis and on the predictive accuracy regarding clinical outcome. Methods Echocardiographic and anthropometric data from a retrospective cohort of 2843 patients with aortic stenosis (jet velocity >2.5m/s) and from 1525 patients prospectively followed in the simvastatin and ezetimibe in aortic stenosis (SEAS) trial were analysed. Results The prevalence of severe stenosis increased with the AVA(index) criterion compared to AVA from 71% to 80% in the retrospective cohort, and from 29% to 44% in SEAS (both p<0.001). Overall, the predictive accuracy for aortic valve events was virtually identical for AVA and AVA(index) in the SEAS population (mean follow-up of 46months; area under the receiver operating characteristic curve: 0.67 (95% CI 0.64 to 0.70) vs 0.68 (CI 0.65 to 0.71) (NS). However, 213 patients additionally categorised as severe by AVA(index) experienced significantly less valve related events than those fulfilling only the AVA criterion (p<0.001). Conclusions Indexing AVA by BSA (AVA(index)) significantly increases the prevalence of patients with criteria for severe stenosis by including patients with a milder degree of the disease without improving the predictive accuracy for aortic valve related events.
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