| 1. |
- Hultman, Karin, 1980, et al.
(författare)
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Allele-specific transcription of the PAI-1 gene in human astrocytes.
- 2010
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Ingår i: Thrombosis and haemostasis. - 0340-6245 .- 2567-689X. ; 104:5, s. 998-1008
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Tidskriftsartikel (refereegranskat)abstract
- The 4G allele of the PAI-1 -675(4G/5G) insertion/deletion promoter polymorphism has been associated with elevated plasma levels of PAI-1 and an increased risk of myocardial infarction. However, this allele has also been associated with a reduced risk of ischaemic stroke. In the brain, PAI-1 is mainly produced by astrocytes, and can reduce the neurotoxic effects exerted by tissue-type plasminogen activator during pathophysiologic conditions. The aim of the present study was to investigate whether the PAI-1 -675(4G/5G) polymorphism and the linked -844A/G polymorphism affect transcriptional activity of the PAI-1 gene in human astrocytes. Haplotype chromatin immunoprecipitation (haploChIP) was used in order to quantify allele-specific promoter activity in heterozygous cells. Protein-DNA interactions were investigated by electrophoretic mobility shift assay (EMSA). A clear allele-specific difference in PAI-1 gene expression was observed in astrocytes, where the haplotype containing the 4G and the -844A alleles was associated with higher transcriptional activity compared to the 5G and -844G-containing haplotype. EMSA revealed an allele-specific binding of nuclear proteins to the 4G/5G site as well as to the -844A/G site. Supershift experiments identified specific binding of the transcription factors Elf-1 and Elk-1 to the -844G allele. The relative impact of the different sites on allele-specific PAI-1 promoter activity remains to be determined. We demonstrate that common polymorphisms within the PAI-1 promoter affect transcriptional activity of the PAI-1 gene in human astrocytes, thus providing a possible molecular genetic mechanism behind the association between PAI-1 promoter variants and ischaemic stroke.
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| 2. |
- Jern, Christina, 1962, et al.
(författare)
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Changes of plasma coagulation and fibrinolysis in response to mental stress.
- 1989
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Ingår i: Thrombosis and haemostasis. - 0340-6245. ; 62:2, s. 767-71
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Tidskriftsartikel (refereegranskat)abstract
- To study the effects of standardized mental stress (arithmetic and the Stroop color word test) on plasma coagulation and fibrinolysis, blood samples were obtained before, during, and after 20 minutes of mental stress from 10 healthy, non-smoking young males aged 22 to 30 years. Reactions were compared with those observed during physical exercise and infusion of adrenaline. Both von Willebrand factor antigen and factor VIII coagulant activity increased significantly in response to mental stress (95 +/- 28 vs 123 +/- 56%; p less than 0.05 and 125 +/- 54 vs 217 +/- 170%; p less than 0.05, respectively). There was also a significant increase of factor VII coagulant activity (86 +/- 31 vs 108 +/- 51%; p less than 0.05). Furthermore, mental stress caused an activation of the fibrinolytic system with an elevation of tissue plasminogen activator activity and tissue plasminogen activator antigen (0.80 +/- 0.48 vs 1.23 +/- 0.96 IU/ml; p = 0.076 and 4.38 +/- 1.87 vs 5.78 +/- 2.58 IU/ml; p less than 0.01). Fibrinogen concentration increased during stress (1.95 +/- 0.29 vs 2.11 +/- 0.27 g/l; p less than 0.05). Similar but more pronounced responses were observed during exercise and adrenaline infusion. Parallel to the increases in coagulation and fibrinolytic factors there were significant increases in heart rate, and systolic and diastolic blood pressure. It is concluded that mental stress has significant effects on plasma coagulation and fibrinolysis, and that it could thus affect important risk factors for cardiovascular disease.
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| 3. |
- Jern, Christina, 1962, et al.
(författare)
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Evidence of a net release of tissue-type plasminogen activator across the human cerebral vasculature.
- 2004
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Ingår i: Thrombosis and haemostasis. - 0340-6245. ; 91:5, s. 1019-25
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Tidskriftsartikel (refereegranskat)abstract
- We have earlier described models for measuring local net release rates of tissue-type plasminogen activator (t-PA) in vivo across skeletal, coronary, pulmonary, and splanchnic vascular beds. Aim of the present study was to investigate whether there is a net release of t-PA across the human cerebral vascular bed and whether an acute regulated release can be induced by sympathoadrenal activation. Fourteen male subjects undergoing elective coronary artery bypass grafting were investigated prior to surgery and during sternotomy-induced sympathoadrenal activation. Blood samples were obtained simultaneously from the radial artery and the jugular bulb. Blood flow velocity in the middle cerebral artery (V(MCA)) was determined by transcranial Doppler. Cerebral net release of t-PA was calculated as the arterio-venous concentration gradient times V(MCA). Prior to surgery there was a significant cerebral net release of t-PA (131 and 42 ng/min for t-PA antigen and activity, respectively). The release was significantly induced by sternotomy (to 271 and 80 ng/min, respectively). No significant cerebral net release of plasminogen activator inhibitor type 1 (PAI-1) was detected throughout the experiment. The results show that there is a basal net release of t-PA across the human cerebral vascular bed and that sympathoadrenal activation induces a local regulated release of t-PA.
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| 4. |
- Ladenvall, Per, 1972, et al.
(författare)
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Tissue-type plasminogen activator -7,351C/T enhancer polymorphism is associated with a first myocardial infarction.
- 2002
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Ingår i: Thrombosis and haemostasis. - 0340-6245. ; 87:1, s. 105-9
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Tidskriftsartikel (refereegranskat)abstract
- We recently identified a polymorphic Sp1 binding site in an enhancer at the tissue-type plasminogen activator (tPA) locus (tPA -7,351C/T), which was associated with vascular tPA release. Subjects homozygous for the -7,351C allele had twice the tPA release rate compared to subjects carrying the -7,351T allele. In this study we tested the hypothesis that the tPA -7,351C/T polymorphism is associated with myocardial infarction (MI). In a population-based prospective nested case-control study within northern Sweden, genotypes were determined among 61 MI cases and 120 controls. In a multivariate model, the tPA -7,351C/T polymorphism (OR 2.68 for T allele carriers; 95% CI 1.31-5.50), tPA antigen (OR 1.16; 95% CI 1.07-1.25) and apo A-I (OR, 0.997; 95% CI 0.995-0.999) were independently associated with a first MI. These findings suggest that genetic markers of local tPA release and circulating steady-state tPA levels carry independent prognostic information.
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| 5. |
- Olsson Lindvall, Martina, et al.
(författare)
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A Comprehensive Sequencing-Based Analysis of Allelic Methylation Patterns in Hemostatic Genes in Human Liver
- 2020
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Ingår i: Thrombosis and Haemostasis. - : Georg Thieme Verlag KG. - 0340-6245 .- 2567-689X. ; 120:2, s. 229-242
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Tidskriftsartikel (refereegranskat)abstract
- Characterizing the relationship between genetic, epigenetic (e.g., deoxyribonucleic acid [DNA] methylation), and transcript variation could provide insights into mechanisms regulating hemostasis and potentially identify new drug targets. Several hemostatic factors are synthesized in the liver, yet high-resolution DNA methylation data from human liver tissue is currently lacking for these genes. Single-nucleotide polymorphisms (SNPs) can influence DNA methylation in cis which can affect gene expression. This can be analyzed through allele-specific methylation (ASM) experiments. We performed targeted genomic DNA- and bisulfite-sequencing of 35 hemostatic genes in human liver samples for SNP and DNA methylation analysis, respectively, and integrated the data for ASM determination. ASM-associated SNPs (ASM-SNPs) were tested for association to gene expression in liver using in-house generated ribonucleic acid-sequencing data. We then assessed whether ASM-SNPs associated with gene expression, plasma proteins, or other traits relevant for hemostasis using publicly available data. We identified 112 candidate ASM-SNPs. Of these, 68% were associated with expression of their respective genes in human liver or in other human tissues and 54% were associated with the respective plasma protein levels, activity, or other relevant hemostatic genome-wide association study traits such as venous thromboembolism, coronary artery disease, stroke, and warfarin dose maintenance. Our study provides the first detailed map of the DNA methylation landscape and ASM analysis of hemostatic genes in human liver tissue, and suggests that methylation regulated by genetic variants in cis may provide a mechanistic link between noncoding SNPs and variation observed in circulating hemostatic proteins, prothrombotic diseases, and drug response.
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| 6. |
- Olsson Lindvall, Martina, et al.
(författare)
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Comparison of DNA Methylation Profiles of Hemostatic Genes between Liver Tissue and Peripheral Blood within Individuals
- 2021
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Ingår i: Thrombosis and Haemostasis. - : Georg Thieme Verlag KG. - 0340-6245 .- 2567-689X. ; 121:5, s. 573-583
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Tidskriftsartikel (refereegranskat)abstract
- DNA methylation has become increasingly recognized in the etiology of complex diseases, including thrombotic disorders. Blood is often collected in epidemiological studies for genotyping and has recently also been used to examine DNA methylation in epigenome-wide association studies. DNA methylation patterns are often tissue-specific, thus, peripheral blood may not accurately reflect the methylation pattern in the tissue of relevance. Here, we collected paired liver and blood samples concurrently from 27 individuals undergoing liver surgery. We performed targeted bisulfite sequencing for a set of 35 hemostatic genes primarily expressed in liver to analyze DNA methylation levels of >10,000 cytosine-phosphate-guanine (CpG) dinucleotides. We evaluated whether DNA methylation in blood could serve as a proxy for DNA methylation in liver at individual CpGs. Approximately 30% of CpGs were nonvariable and were predominantly hypo- (<25%) or hypermethylated (>70%) in both tissues. While blood can serve as a proxy for liver at these CpGs, the low variability renders these unlikely to explain phenotypic differences. We therefore focused on CpG sites with variable methylation levels in liver. The level of blood-liver tissue correlation varied widely across these variable CpGs; moderate correlations (0.5 <= r <0.75) were detected for 6% and strong correlations ( r 0.75) for a further 4%. Our findings indicate that it is essential to study the concordance of DNA methylation between blood and liver at individual CpGs. This paired blood-liver dataset is intended as a resource to aid interpretation of blood-based DNA methylation results.
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| 7. |
- Olsson Lindvall, Martina, et al.
(författare)
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Hemostatic Genes Exhibit a High Degree of Allele-Specific Regulation in Liver
- 2019
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Ingår i: Thrombosis and Haemostasis. - : Georg Thieme Verlag KG. - 0340-6245 .- 2567-689X. ; 119:7, s. 1072-1083
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Tidskriftsartikel (refereegranskat)abstract
- Objective Elucidating the genetic basis underlying hepatic hemostatic gene expression variability may contribute to unraveling genetic factors contributing to thrombotic or bleeding disorders. We aimed to identify novel cis-regulatory variants involved in regulating hemostatic genes by analyzing allele-specific expression (ASE) in human liver samples. Study Design Biopsies of human liver tissue and blood were collected from adults undergoing liver surgery at the Sahlgrenska University Hospital (n =20). Genomic deoxyribonucleic acid (gDNA) and total ribonucleic acid (RNA) were isolated. A targeted approach was used to enrich and sequence 35 hemostatic genes for single nucleotide polymorphism (SNP) analysis (gDNAseq) and construct individualized genomes for transcript alignment. The allelic ratio of transcripts from targeted RNAseq was determined via ASE analysis. Public expression quantitative trait loci (eQTL) and genome-wide association study (GWAS) data were used to assess novelty and importance of the ASE SNPs (and proxies, r(2) >= 0.8) for relevant traits/diseases. Results Sixty percent of the genes studied showed allelic imbalance across 53 SNPs. Of these, 7 SNPs were previously validated in liver eQTL studies. For 32 with eQTLs in other cell/tissue types, this is the first time genotype-specific expression is demonstrated in liver, and for 14 ASE SNPs, this is the first ever reported genotype-expression association. A total of 29 ASE SNPs were previously associated with the respective plasma protein levels and 17 ASE SNPs to other relevant GWAS traits including venous thromboembolism, coronary artery disease, and stroke. Conclusion Our study provides a comprehensive ASE analysis of hemostatic genes and insights into the regulation of hemostatic genes in human liver.
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| 8. |
- Osterlund, Barbro, et al.
(författare)
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Intracoronary beta2 receptor activation induces dynamic local t-PA release in the pig.
- 2003
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Ingår i: Thrombosis and haemostasis. - 0340-6245 .- 2567-689X. ; 90:5, s. 796-802
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Tidskriftsartikel (refereegranskat)abstract
- To investigate beta2 -adrenergic agonist-mediated effects on coronary fluxes of local fibrinolytic factors, healthy anaesthetised and instrumented pigs (n=10) were studied during infusion of isoprenaline (IPR) into the left main coronary artery. Coronary net fluxes of total t-PA antigen, active t-PA and total PAI-1 antigen were determined at baseline and at 3, 5, 7 and 10 minutes of IPR infusion. During IPR, net release of total t-PA increased in a biphasic pattern with transiently high levels at 3 (+440 %) and 7 minutes (+620%) and returned towards baseline at 10 minutes. Net coronary release of active t-PA increased with maximum levels at 3 minutes (+50%). Baseline coronary net flux of total PAI -1 showed a decrease which was most pronounced at 10 minutes. To conclude, a fast beta2 agonist-mediated local release of t-PA into the coronary vasculature was demonstrated. For total t-PA, this response was characterised by a biphasic release profile.
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| 9. |
- Pedersen, Annie, 1981, et al.
(författare)
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Haemostatic biomarkers are associated with long-term recurrent vascular events after ischaemic stroke
- 2016
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Ingår i: Thrombosis and Haemostasis. - : Georg Thieme Verlag KG. - 0340-6245 .- 2567-689X. ; 116:3, s. 537-543
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Tidskriftsartikel (refereegranskat)abstract
- Ischaemic stroke patients continue to be at risk for recurrent vascular events for many years. Predictors of long-term prognosis are needed. It was the objective of this study to investigate levels of four haemostatic proteins as long-term predictors of recurrent vascular events after ischaemic stroke. We prospectively followed 548 ischaemic stroke patients, 18-69 years, and registered recurrent vascular events. Plasma levels of tissue-type plasminogen activator (t-PA), von Willebrand factor (VWF), fibrinogen and thrombin activatable fibrinolysis inhibitor activation peptide (TAFI-AP) were measured three months after index stroke. Cox regression models were used to assess associations to outcomes for single biomarkers and for a combined biomarker measure. For single biomarkers significantly associated with any of the outcomes, we performed subanalyses stratified for age, sex, diabetes and atherosclerosis. During 5,637 person-years of follow-up, we registered 74 vascular deaths, 90 recurrent strokes and 62 coronary events. Levels of t-PA, VWF and fibrinogen were significantly associated with vascular death and coronary events. After adjustment, the association between t-PA and vascular death remained (HR per 1 SD increase in plasma level 1.27, 95 % CI 1.00-1.61, p=0.047). The combined effect of t-PA, VWF and fibrinogen was associated with coronary events (adjusted HR 1.35, 1.02-1.80, p=0.04). In non-diabetic patients, an association with coronary events was seen for VWF levels (adjusted HR 2.23,1.45-3.43, p
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| 10. |
- Stanne, Tara M, 1979, et al.
(författare)
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A Genome-wide Study of Common and Rare Genetic Variants Associated with Circulating Thrombin Activatable Fibrinolysis Inhibitor
- 2018
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Ingår i: Thrombosis and Haemostasis. - : Georg Thieme Verlag KG. - 0340-6245 .- 2567-689X. ; 118:2, s. 298-308
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Tidskriftsartikel (refereegranskat)abstract
- Thrombin-activatable fibrinolysis inhibitor (TAFI) plays a central role in haemostasis, and plasma TAFI concentrations are heritable. Candidate gene studies have identified several variants within the gene encoding TAFI, CPB2, that explain part of the estimated heritability. Here, we describe an exploratory genome-wide association study to identify novel variants within and outside of the CPB2 locus that influence plasma concentrations of intact TAFI and/or the extent of TAFI activation (measured by released TAFI activation peptide, TAFI-AP) amongst 3,260 subjects from Southern Sweden. We also explored the role of rare variants on the HumanExome BeadChip. We confirmed the association with previously reported common variants in CPB2 for both intact TAFI and TAFI-AP, and discovered novel associations with variants in putative CPB2 enhancers. We identified a gene-based association with intact TAFI at CPB2 (PSKAT-O = 2.8 x 10(-8)), driven by two novel rare nonsynonymous single nucleotide polymorphisms (SNPs; I420N and D177G). Carriers of the rare variant of D177G (rs140446990; MAF 0.2%) had lower intact TAFI and TAFI-AP concentrations compared with non-carriers (intact TAFI, geometricmean 53 vs. 78%, PT-test < 5 x 10(-7); TAFI-AP 63 vs. 99%, P(T-tes)t = 7.2 x 10(-4)). For TAFI-AP, we identified a genome-wide significant association at an intergenic region of chromosome 3p14.1 and five gene-based associations (all PSKAT-O = 5 x 10(-6)). Using well-characterized assays together with a genome-wide association study and a rare-variant approach, we verified CPB2 to be the primary determinant of TAFI concentrations and identified putative secondary loci (candidate variants and genes) associated with intact TAFI and TAFI-AP that require independent validation.
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