| 1. |
- Brinkman, Herm Jan M., et al.
(författare)
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Pleiotropic anticoagulant functions of protein S, consequences for the clinical laboratory. Communication from the SSC of the ISTH
- 2021
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Ingår i: Journal of Thrombosis and Haemostasis. - : Elsevier BV. - 1538-7933 .- 1538-7836. ; 19:1, s. 281-286
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Tidskriftsartikel (refereegranskat)abstract
- Hereditary deficiencies of protein S (PS) increase the risk of thrombosis. However, assessing the plasma levels of PS is complicated by its manifold physiological interactions, while the large inter-individual variability makes it problematic to establish reliable cut-off values. PS has multiple physiological functions, with only two appearing to have significant anticoagulant properties: the activated protein C (APC) and tissue factor pathway inhibitor alpha (TFPIα) cofactor activities. Current clinical laboratory investigations for deficiency in PS function rely only on the APC-dependent activity. This communication presents an argument for reclassifying the qualitative PS deficiencies to differentiate the two major anticoagulant functions of PS. Reliable assays are necessary for accurate evaluation of PS function when making a specific diagnosis of PS deficiency based on the anticoagulant phenotype alone. This report emphasizes the pleiotropic anticoagulant functions of PS and presents evidence-based recommendations for their implementation in the clinical laboratory.
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| 2. |
- Chirinos, Julio A., et al.
(författare)
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Reduced Apolipoprotein M and Adverse Outcomes across the Spectrum of Human Heart Failure
- 2020
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Ingår i: Circulation. - 0009-7322. ; , s. 1463-1476
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Tidskriftsartikel (refereegranskat)abstract
- Background: Apo (apolipoprotein) M mediates the physical interaction between high-density lipoprotein (HDL) particles and sphingosine-1-phosphate (S1P). Apo M exerts anti-inflammatory and cardioprotective effects in animal models. Methods: In a subset of PHFS (Penn Heart Failure Study) participants (n=297), we measured apo M by Enzyme-Linked ImmunoSorbent Assay (ELISA). We also measured total S1P by liquid chromatography-mass spectrometry and isolated HDL particles to test the association between apo M and HDL-associated S1P. We confirmed the relationship between apo M and outcomes using modified aptamer-based apo M measurements among 2170 adults in the PHFS and 2 independent cohorts: the Washington University Heart Failure Registry (n=173) and a subset of TOPCAT (Treatment of Preserved Cardiac Function Heart Failure With an Aldosterone Antagonist Trial; n=218). Last, we examined the relationship between apo M and ≈5000 other proteins (SomaScan assay) to identify biological pathways associated with apo M in heart failure. Results: In the PHFS, apo M was inversely associated with the risk of death (standardized hazard ratio, 0.56 [95% CI, 0.51-0.61]; P<0.0001) and the composite of death/ventricular assist device implantation/heart transplantation (standardized hazard ratio, 0.62 [95% CI, 0.58-0.67]; P<0.0001). This relationship was independent of HDL cholesterol or apo AI levels. Apo M remained associated with death (hazard ratio, 0.78 [95% CI, 0.69-0.88]; P<0.0001) and the composite of death/ventricular assist device/heart transplantation (hazard ratio, 0.85 [95% CI, 0.76-0.94]; P=0.001) in models that adjusted for multiple confounders. This association was present in both heart failure with reduced and preserved ejection fraction and was replicated in the Washington University cohort and a cohort with heart failure with preserved ejection fraction only (TOPCAT). The S1P and apo M content of isolated HDL particles strongly correlated (R=0.81, P<0.0001). The top canonical pathways associated with apo M were inflammation (negative association), the coagulation system (negative association), and liver X receptor/retinoid X receptor activation (positive association). The relationship with inflammation was validated with multiple inflammatory markers measured with independent assays. Conclusions: Reduced circulating apo M is independently associated with adverse outcomes across the spectrum of human heart failure. Further research is needed to assess whether the apo M/S1P axis is a suitable therapeutic target in heart failure.
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| 3. |
- Dahlbäck, Björn, et al.
(författare)
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A hydrophobic patch (PLVIVG; 1481–1486) in the B-domain of factor V-short is crucial for its synergistic TFPIα-cofactor activity with protein S and for the formation of the FXa-inhibitory complex comprising FV-short, TFPIα, and protein S
- 2022
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Ingår i: Journal of Thrombosis and Haemostasis. - : Elsevier BV. - 1538-7933 .- 1538-7836. ; 20:5, s. 1146-1157
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Tidskriftsartikel (refereegranskat)abstract
- Background: Factor V-short (FV756-1458) is a natural splice variant functioning in synergy with protein S as tissue factor pathway inhibitor alpha (TFPIα)–cofactor in inhibition of factor Xa (FXa). An exposed acid region (AR2; 1493–1537) in the B domain binds TFPIα. The preAR2 (1458–1492) is crucial for the synergistic TFPIα–cofactor activity between FV-short and protein S and for assembly of a trimolecular FXa-inhibitory complex among FV-short, protein S, and TFPIα. Objective: To identify which part of preAR2 is required for the synergistic TFPIα–cofactor activity between FV-short and protein S. Methods: A FXa-inhibition assay was used to test the synergistic TFPIα cofactor activity between protein S and new FV-short variants FV709-1476, FV712-1478, FV712-1481, FV712-1484, FV712-1487, and FV712-1490. A microtiter-based assay analyzed binding among FV-short variants, protein S, and TFPIα. Results: FV709-1476, FV712-1478, and FV712-1481 were fully active as synergistic TFPIα cofactors with protein S; FV712-1484 showed intermediate activity; and FV712-1487 and FV712-1490 were inactive. TFPIα interacted with all variants in the absence of protein S but FV712-1478 and FV712-1481 bound TFPIα with highest affinity. None of the FV-short variants bound directly to protein S in the absence of TFPIα. In the presence of TFPIα, efficient cooperative binding was demonstrated between protein S, TFPIα, and FV709-1476, FV712-1478, or FV712-1481. In contrast, no cooperativity among TFPIα, protein S, and FV712-1484, FV712-1487, or FV712-1490 was seen. Conclusion: A short hydrophobic patch in preAR2 (PLVIVG, 1481–1486) in FV-short is crucial for the synergistic TFPIα-cofactor activity between FV-short and protein S and for the assembly of a trimolecular FXa-inhibitory complex among FV-short, protein S, and TFPIα.
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| 4. |
- Dahlbäck, Björn
(författare)
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Natural anticoagulant discovery, the gift that keeps on giving : finding FV-Short
- 2023
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Ingår i: Journal of Thrombosis and Haemostasis. - : Elsevier BV. - 1538-7933 .- 1538-7836. ; 21:4, s. 716-727
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Forskningsöversikt (refereegranskat)abstract
- The complex reactions of blood coagulation are balanced by several natural anticoagulants resulting in tuned hemostasis. During several decades, the knowledge base of the natural anticoagulants has greatly increased and we have also learned about antiinflammatory and cytoprotective activities expressed by antithrombin and activated protein C (APC). Some coagulation proteins have also been found to function as anticoagulants; e.g., thrombin when bound to thrombomodulin activates protein C. Another example is factor V (FV), which in addition to being a procofactor to FVa has emerged as an anticoagulant. The discovery of APC resistance, caused by FVLeiden, as a thrombosis risk factor resulted in the identification of FV as an APC cofactor working in synergy with protein S in the regulation of FVIIIa in the Xase complex. More recently, a natural anticoagulant FV splice isoform (FV-Short) was discovered when investigating the East Texas bleeding disorder. In FV-Short, the truncated B domain exposes a high-affinity binding site for tissue factor pathway inhibitor alpha (TFPIα), and together with protein S a high-affinity trimolecular complex is generated. The FXa-inhibitory activity of TFPIα is synergistically stimulated by FV-Short and protein S. The circulating FV-Short/protein S/TFPIα complex concentration is normally low (≈0.2 nM) but provides an anticoagulant threshold. In the East Texas bleeding, the concentration of the complex, and thus the threshold, is increased 10-fold, which results in bleeding manifestations. The anticoagulant properties of FV were discovered during investigations of individual patients and follow the great tradition of bed-to-bench and bench-to-bed research in the coagulation field.
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| 5. |
- Dahlbäck, Björn, et al.
(författare)
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The preAR2 region (1458–1492) in factor V-Short is crucial for the synergistic TFPIα-cofactor activity with protein S and the assembly of a trimolecular factor Xa-inhibitory complex comprising FV-Short, protein S, and TFPIα
- 2022
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Ingår i: Journal of Thrombosis and Haemostasis. - : Elsevier BV. - 1538-7933 .- 1538-7836. ; 20:1, s. 58-68
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Tidskriftsartikel (refereegranskat)abstract
- Background: Factor V-Short (FV756-1458) is a natural splice variant in which 702 residues are deleted from the B domain. It exposes an acid region (AR2; 1493–1537) that binds tissue factor pathway inhibitor alpha (TFPIα). Protein S also interacts with TFPIα and serves as TFPIα-cofactor in factor Xa (FXa) inhibition. FV-Short and protein S function as synergistic TFPIα-cofactors in inhibition of FXa. FV810-1492 is an artificial FV-Short variant that cannot synergize with protein S as TFPIα cofactor even though it contains AR2 and binds TFPIα. Objective: To elucidate the mechanisms for the synergism between FV756-1458 and protein S as TFPIα cofactors. Methods: Four FV-Short variants were created, FV756-1458 and FV712-1458 contained the preAR2 region (1458–1492), whereas FV810-1492 and FV713-1492 lacked this region. The synergistic TFPIα cofactor activity between FV-Short variants and protein S was analyzed by FXa-inhibition. A microtiter-based assay tested binding between FV-Short variants, protein S, and TFPIα. Results: The two preAR2-containing FV-Short variants were active as synergistic TFPIα cofactors, whereas the other two were inactive. All variants bound to TFPIα. None of the FV-Short variants bound directly to protein S. The combination of TFPIα and preAR2-containing FV-Short variants bound protein S, whereas TFPIα together with the preAR2-minus variants did not. Protein S potentiated TFPIα-binding to the preAR2-containing variants and binding between TFPIα and protein S was stimulated only by the preAR2-containing variants. Conclusion: The preAR2 region is demonstrated to be crucial for the synergistic TFPIα-cofactor activity between FV-Short and protein S and for the assembly of a trimolecular FXa-inhibitory complex comprising FV-Short, protein S, and TFPIα.
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| 6. |
- Dahlbäck, Cecilia, et al.
(författare)
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Long-term outcome of lymph vessel transplantation after chronic lymphorrhea
- 2021
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Ingår i: Case Reports in Plastic Surgery and Hand Surgery. - : Informa UK Limited. - 2332-0885. ; 8:1, s. 169-174
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Tidskriftsartikel (refereegranskat)abstract
- A 52-year-old male patient developed a chronic fistula with excessive lymph leakage in the left axilla following removal of an enlarged lymph node with chronic local adipose tissue inflammation due to infection. After multiple surgeries, treatment with lymphatic vessel transplantation was successful. No recurrence occurred over 20 years of follow-up.
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| 7. |
- Manderstedt, Eric, et al.
(författare)
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Classic Thrombophilias and Thrombotic Risk Among Middle-Aged and Older Adults : A Population-Based Cohort Study
- 2022
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Ingår i: Journal of the American Heart Association. - : Wiley-Blackwell Publishing Ltd. - 2047-9980. ; 11:4
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Five classic thrombophilias have been recognized: factor V Leiden (rs6025), the prothrombin G20210A variant (rs1799963), and protein C, protein S, and antithrombin deficiencies. This study aimed to determine the thrombotic risk of classic thrombophilias in a cohort of middle-aged and older adults. METHODS AND RESULTS: Factor V Leiden, prothrombin G20210A and protein-coding variants in the PROC (protein C), PROS1 (protein S), and SERPINC1 (antithrombin) anticoagulant genes were determined in 29 387 subjects (born 1923–1950, 60% women) who participated in the Malmö Diet and Cancer study (1991–1996). The Human Gene Mutation Database was used to define 68 disease-causing mutations. Patients were followed up from baseline until the first event of venous thromboembolism (VTE), death, or Dec 31, 2018. Carriership (n=908, 3.1%) for disease-causing mutations in the PROC, PROS1, and SERPINC1 genes was associated with incident VTE: Hazard ratio (HR) was 1.6 (95% CI, 1.3–1.9). Variants not in Human Gene Mutation Database were not linked to VTE (HR, 1.1; 95% CI, 0.8–1.5). Heterozygosity for rs6025 and rs1799963 was associated with incident VTE: HR, 1.8 (95% CI, 1.6–2.0) and HR, 1.6 (95% CI, 1.3–2.0), respectively. The HR for carrying 1 classical thrombophilia variant was 1.7 (95% CI, 1.6–1.9). HR was 3.9 (95% CI, 3.1–5.0) for carriers of ≥2 thrombophilia variants. CONCLUSIONS: The 5 classic thrombophilias are associated with a dose-graded risk of VTE in middle-aged and older adults. Disease-causing variants in the PROC, PROS1, and SERPINC1 genes were more common than the rs1799963 variant but the conferred genetic risk was comparable with the rs6025 and rs1799963 variants.
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| 8. |
- Minford, Adrian, et al.
(författare)
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Diagnosis and management of severe congenital protein C deficiency (SCPCD) : Communication from the SSC of the ISTH
- 2022
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Ingår i: Journal of Thrombosis and Haemostasis. - : Elsevier BV. - 1538-7933 .- 1538-7836. ; 20:7, s. 1735-1743
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Tidskriftsartikel (refereegranskat)abstract
- Severe congenital protein C deficiency (SCPCD) is rare and there is currently substantial variation in the management of this condition. A joint project by three Scientific and Standardization Committees of the ISTH: Plasma Coagulation Inhibitors, Pediatric/Neonatal Thrombosis and Hemostasis, and Women’s Health Issues in Thrombosis and Hemostasis, was developed to review the current evidence and help guide on diagnosis and management of SCPCD. We provide a summary of the clinical presentations, differential diagnoses, appropriate investigations to confirm the diagnosis, approaches for management of the acute situation, and options for long-term management including subsequent pregnancies. We finally provide a set of recommendations to help in this regard.
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| 9. |
- Zöller, Bengt, et al.
(författare)
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Genetic risk factors for venous thromboembolism
- 2020
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Ingår i: Expert Review of Hematology. - 1747-4086 .- 1747-4094. ; 13:9, s. 971-981
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Tidskriftsartikel (refereegranskat)abstract
- INTRODUCTION: Venous thromboembolism (VTE) is a complex disease that aggregates in families. Both acquired and genetic risk factors are important. Proper recognition and management of high-risk individuals are important.AREAS COVERED: The genetic risk factors for VTE, the clinical consequences, and future perspectives are summarized. Classical thrombophilia i.e. factor V Leiden (rs6025), the prothrombin G20210A mutation (rs1799963), deficiencies of antithrombin, protein C, and protein S and the recent findings from genome wide association studies (GWAS), transcriptome-wide association studies (TWAS), genetic risk score (GRS), VTE candidate genes, expression studies, animal studies, studies using next generation sequencing, pathway analysis, and clinical implications are discussed.EXPERT OPINION: Screening of inherited thrombophilia should be performed in special cases. Identification of strong risk variants might affect the management. The increasing number of genetic risk variants is likely to change management of VTE.
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| 10. |
- Zöller, Bengt, et al.
(författare)
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Genetic risk factors for venous thromboembolism
- 2020
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Ingår i: Expert Review of Hematology. - : Informa UK Limited. - 1747-4086 .- 1747-4094. ; 13:9, s. 971-981
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Forskningsöversikt (refereegranskat)abstract
- Introduction: Venous thromboembolism (VTE) is a complex disease that aggregates in families. Both acquired and genetic risk factors are important. Proper recognition and management of high-risk individuals are important. Areas covered: The genetic risk factors for VTE, the clinical consequences, and future perspectives are summarized. Classical thrombophilia i.e., factor V Leiden (rs6025), the prothrombin G20210A mutation (rs1799963), deficiencies of antithrombin, protein C, and protein S and the recent findings from genome wide association studies (GWAS), transcriptome-wide association studies (TWAS), genetic risk score (GRS), VTE candidate genes, expression studies, animal studies, studies using next generation sequencing, pathway analysis, and clinical implications are discussed. Expert opinion: Screening of inherited thrombophilia should be performed in special cases. Identification of strong risk variants might affect the management. The increasing number of genetic risk variants is likely to change management of VTE.
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