| 1. |
- Chernogubova, Ekaterina, et al.
(author)
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Common and Low-Frequency Genetic Variants in the PCSK9 Locus Influence Circulating PCSK9 Levels
- 2012
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In: Arteriosclerosis, Thrombosis and Vascular Biology. - 1079-5642 .- 1524-4636. ; 32:6, s. 1526-1534
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Journal article (peer-reviewed)abstract
- Objective- Proprotein convertase subtilisin/kexin type 9 (PCSK9) is a circulating protein that influences plasma low-density lipoprotein concentration and susceptibility to coronary heart disease. Circulating PCSK9 levels show considerable interindividual differences, but the factors responsible for this variation are largely unknown. Methods and Results- We analyzed circulating PCSK9 levels in 4 cohorts of healthy, middle-aged Swedes (n=5722) and found that PCSK9 levels varied over approximate to 50-fold range, showed a positive relationship with plasma low-density lipoprotein-cholesterol concentration, and were associated with plasma triglyceride, fibrinogen, insulin, and glucose concentrations. A genome-wide association study conducted in 2 cohorts (n=1215) failed to uncover common genetic variants robustly associated with variation in circulating PCSK9 level. As expected, the minor allele of the PCSK9 R46L variant was in all cohorts associated with reduced PCSK9 levels and decreased plasma low-density lipoprotein-cholesterol concentrations, but no relationship was observed with the plasma triglyceride concentration. Further mapping of the PCSK9 locus revealed a common polymorphism (rs2479415, minor allele frequency 43.9%), located approximate to 6 kb upstream from PCSK9, which is independently associated with increased circulating PCSK9 levels. Conclusion- Common and low-frequency genetic variants in the PCSK9 locus influence the pronounced interindividual variation in circulating PCSK9 levels in healthy, middle-aged white (predominantly Swedish) subjects.
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| 2. |
- Gertow, Karl, et al.
(author)
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Identification of the BCAR1-CFDP1-TMEM170A Locus as a Determinant of Carotid Intima-Media Thickness and Coronary Artery Disease Risk
- 2012
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In: Circulation: Cardiovascular Genetics. - 1942-325X .- 1942-3268. ; 5:6, s. 656-665
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Journal article (peer-reviewed)abstract
- Background-Carotid intima-media thickness (cIMT) is a widely accepted marker of subclinical atherosclerosis. To date, large-scale investigations of genetic determinants of cIMT are sparse. Methods and Results-To identify cIMT-associated genes and genetic variants, a discovery analysis using the Illumina 200K CardioMetabochip was conducted in 3430 subjects with detailed ultrasonographic determinations of cIMT from the IMPROVE (Carotid Intima Media Thickness [IMT] and IMT-Progression as Predictors of Vascular Events in a High Risk European Population) study. Segment-specific IMT measurements of common carotid, bifurcation, and internal carotid arteries, and composite IMT variables considering the whole carotid tree (IMTmean, IMTmax, and IMTmean-max), were analyzed. A replication stage investigating 42 single-nucleotide polymorphisms for association with common carotid IMT was undertaken in 5 independent European cohorts (total n=11 590). A locus on chromosome 16 (lead single-nucleotide polymorphism rs4888378, intronic in CFDP1) was associated with cIMT at significance levels passing multiple testing correction at both stages (array-wide significant discovery P=6.75x10(-7) for IMTmax; replication P=7.24x10(-6) for common cIMT; adjustments for sex, age, and population substructure where applicable; minor allele frequency 0.43 and 0.41, respectively). The protective minor allele was associated with lower carotid plaque score in a replication cohort (P=0.04, n=2120) and lower coronary artery disease risk in 2 case-control studies of subjects with European ancestry (odds ratio [95% confidence interval] 0.83 [0.77-0.90], P=6.53x10(-6), n=13 591; and 0.95 [0.92-0.98], P=1.83x10(-4), n= 82 297, respectively). Queries of human biobank data sets revealed associations of rs4888378 with nearby gene expression in vascular tissues (n=126-138). Conclusions-This study identified rs4888378 in the BCAR1-CFDP1-TMEM170A locus as a novel genetic determinant of cIMT and coronary artery disease risk in individuals of European descent. (Circ Cardiovasc Genet. 2012;5:656-665.)
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| 3. |
- Scott, Robert A., et al.
(author)
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Large-scale association analyses identify new loci influencing glycemic traits and provide insight into the underlying biological pathways
- 2012
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In: Nature Genetics. - : Springer Science and Business Media LLC. - 1061-4036 .- 1546-1718. ; 44:9, s. 991-1005
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Journal article (peer-reviewed)abstract
- Through genome-wide association meta-analyses of up to 133,010 individuals of European ancestry without diabetes, including individuals newly genotyped using the Metabochip, we have increased the number of confirmed loci influencing glycemic traits to 53, of which 33 also increase type 2 diabetes risk (q < 0.05). Loci influencing fasting insulin concentration showed association with lipid levels and fat distribution, suggesting impact on insulin resistance. Gene-based analyses identified further biologically plausible loci, suggesting that additional loci beyond those reaching genome-wide significance are likely to represent real associations. This conclusion is supported by an excess of directionally consistent and nominally significant signals between discovery and follow-up studies. Functional analysis of these newly discovered loci will further improve our understanding of glycemic control.
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| 4. |
- Jackson, Veronica, et al.
(author)
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Matrix metalloproteinase 14 and 19 expression is associated with thoracic aortic aneurysms
- 2012
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In: Journal of Thoracic and Cardiovascular Surgery. - : Elsevier. - 0022-5223 .- 1097-685X. ; 144:2, s. 459-466
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Journal article (peer-reviewed)abstract
- OBJECTIVE:It is hypothesized that an altered turnover of extracellular matrix mediated by matrix metalloproteinases (MMPs) is present in thoracic aortic aneurysms. Here, we analyzed the occurrence of MMPs and MMP inhibitors in ascending aortic aneurysms in patients with bicuspid and tricuspid aortic valves.METHODS:Expression of 23 MMPs and their inhibitors was measured in aortic intima/media and adventitia in 109 patients (40 tricuspid, 69 bicuspid, 68 with aortic diameter≥4.5 cm, and 41 with ≤4.0 cm) using Affymetrix Exon arrays (Affymetrix, Santa Clara, Calif). Gene expression was confirmed by quantitative real-time polymerase chain reaction. Principal components analysis was used to study differences in gene expression. Immunohistochemistry was used to study protein expression.RESULTS:We detected messenger RNA expression for gelatinases (MMP2 and MMP9), stromelysin 3 (MMP11), all membrane bound MMPs (MMP14, MMP15, MMP16, MMP17, MMP24, MMP25), MMP19, MMP21, and MMP28 in ascending aorta. No expression of collagenases was detected. Principal components analysis showed that changes in mRNA expression between dilated and nondilated aorta were mainly detected in patients with tricuspid aortic valves. MMP14 and MMP19 showed higher expression in dilated aortas and MMP19 expression correlated positively to maximal aortic diameter in patients with tricuspid aortic valves (Rho=0.61, P=.004, and Rho=0.57, P=.008, using raw and body surface area-corrected aortic diameter, respectively). Immunohistochemical staining demonstrated increased medial expression of MMP14 and MMP19 in dilated aorta.CONCLUSIONS:The present study identifies MMP14 and MMP19 as proteolytic enzymes potentially involved in aneurysm formation in the ascending aorta of patients with tricuspid aortic valves
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| 5. |
- Kolak, Maria, et al.
(author)
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Expression of ceramide-metabolising enzymes in subcutaneous and intra-abdominal human adipose tissue
- 2012
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In: Lipids in Health and Disease. - : BioMed Central (BMC). - 1476-511X. ; 11
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Journal article (peer-reviewed)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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