Publications by authors named "Thomas Renne"

142 Publications

Monocyte activation and acquired autoimmune protein S deficiency promote disseminated intravascular coagulation in a patient with primary antiphospholipid syndrome.

Res Pract Thromb Haemost 2021 Jul 28;5(5):e12559. Epub 2021 Jun 28.

Department of Hematology and Oncology University Cancer Center Hamburg (UCCH) University Medical Center Eppendorf Hamburg Germany.

Autoimmune protein S (PS) deficiency is a highly thrombotic, potentially life-threatening disorder. Its pathophysiological relevance in the context of primary antiphospholipid syndrome (APS) is unclear. Here, we report the case of a 76-year-old woman, who presented with a painful reticular skin erythema caused by microvascular thromboses. Disseminated intravascular coagulation (DIC) with consumptive coagulopathy was controlled only by continuous anticoagulation. While significantly elevated IgM antibodies to cardiolipin and β-glycoprotein-I were consistent with primary APS, a function-blocking PS autoantibody of the IgG isotype was detected. Robust microvesicle (MV)-associated tissue factor (TF) procoagulant activity (PCA) was isolated from patient plasma. Moreover, patient IgG, but not IgM, induced expression of TF PCA and release of TF-bearing MVs by peripheral blood mononuclear cells from healthy donors. In primary APS, induction of monocyte TF in combination with an acquired PS inhibitor may provoke a deleterious imbalance of procoagulant and anticoagulant pathways with evolution of thrombotic DIC.
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http://dx.doi.org/10.1002/rth2.12559DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8265818PMC
July 2021

Diagnostic Validation of a High-Sensitivity Cardiac Troponin I Assay.

Clin Chem 2021 Jul 13. Epub 2021 Jul 13.

Department of Cardiology, University Heart and Vascular Center Hamburg, Hamburg, Germany.

Background: Emergency departments worldwide are increasingly adopting rapid diagnosis of patients with suspected myocardial infarction (MI) based on high-sensitivity troponin. We set out to assess the diagnostic accuracy of a high-sensitivity cardiac troponin I (hs-cTnI) assay in a prospective study.

Methods: In a cohort study including 1800 patients presenting with suspected acute MI, we developed and temporally validated a 0/1 h diagnostic algorithm using the Siemens Atellica IM hs-cTnI assay. The algorithm was established in the first 928 patients and validated in the following 872 patients.

Results: The derived algorithm consisted of a baseline rule-out of non-ST-segment elevation MI using a cutoff <3 ng/L in patients with symptom onset ≥3 h or an admission troponin I level <6 ng/L with a Δ change of <3 ng/L from 0 h to 1 h. For rule-in, an admission troponin I level ≥120 ng/L or an increase within the first hour ≥12 ng/L was required. Application of the algorithm to the validation cohort showed a negative predictive value of 99.8% (95% CI, 98.7%-100.0%), sensitivity of 99.1% (95% CI, 95.1%-100.0%), and 48.3% of patients ruled out, whereas 15.1% were ruled in with a positive predictive value of 68.0% (95% CI, 59.1%-75.9%) and specificity of 94.4% (95% CI, 92.5%-96.0%). The diagnostic performance was comparable to guideline-recommended application of an established hs-cTnI assay in a rapid 0/1 h strategy.

Conclusions: The Siemens hs-cTnI assay is well suited for application in rapid diagnostic stratification of patients with suspected MI.

Study Registration: www.clinicaltrials.gov (NCT02355457).
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http://dx.doi.org/10.1093/clinchem/hvab070DOI Listing
July 2021

Prevalence and risk factors of undiagnosed diabetes mellitus among gastroenterological patients: a HbA1c-based single center experience.

Z Gastroenterol 2021 Jun 22. Epub 2021 Jun 22.

I. Department of Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.

Background: Diabetes mellitus is a major risk factor for microvascular disease, leading to chronic kidney injury or cardiovascular disease, but there is a tremendous proportion of patients worldwide who suffer from undiagnosed diabetes. Until now, little is known about the prevalence of undiagnosed diabetes in gastroenterology inpatients.

Objective: To improve detection of undiagnosed diabetes, a routine screening procedure for gastroenterology inpatients, based on hemoglobin A1c (HbA1c) and fasting plasma glucose (FPG) measurement, was established.

Methods: We conducted a retrospective analysis of the implemented diabetes screening. Diabetes mellitus was diagnosed according to the guideline of the German Diabetes Association in patients with an HbA1c of ≥6.5% anld/or fasting plasma glucose (FPG) ≥126 mg/dL. Univariate and multivariate analyses were performed to identify independent risk factors for undiagnosed diabetes.

Results: Within a 3-month period, 606 patients were eligible for a diabetes screening. Pre-existing diabetes was documented in 120 patients (19.8 %), undiagnosed diabetes was found in 24 (3.9%), and 162 patients (26.7%) met the definition for prediabetes. Steroid medication use, age, and liver cirrhosis due to primary sclerosing cholangitis (PSC) were identified as risk factors for undiagnosed diabetes.

Conclusion: The prevalence of undiagnosed diabetes in gastroenterology inpatients is markedly elevated in comparison to the general population, and a substantial number of inpatients are in a prediabetic status, underlining the need for diabetes screening. In addition to previously described risk factors of patient age and steroid medication use, we identified PSC-related liver cirrhosis (but not liver cirrhosis due to another etiology) as an independent risk factor for undiagnosed diabetes.
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http://dx.doi.org/10.1055/a-1482-8840DOI Listing
June 2021

The contact system in liver injury.

Semin Immunopathol 2021 Jun 14. Epub 2021 Jun 14.

Institute of Clinical Chemistry and Laboratory Medicine (O26), University Medical Center Hamburg-Eppendorf, Martinistrasse 52, D-20246, Hamburg, Germany.

Coagulation is controlled by a delicate balance of prothrombotic and antithrombotic mechanisms, to prevent both excessive blood loss from injured vessels and pathologic thrombosis. The liver plays a pivotal role in hemostasis through the synthesis of plasma coagulation factors and their inhibitors that, in addition to thrombosis and hemostasis, orchestrates an array of inflammatory responses. As a result, impaired liver function has been linked with both hypercoagulability and bleeding disorders due to a pathologic balance of pro- and anticoagulant plasma factors. At sites of vascular injury, thrombus propagation that finally may occlude the blood vessel depends on negatively charged biopolymers, such as polyphosphates and extracellular DNA, that provide a physiological surface for contact activation of coagulation factor XII (FXII). FXII initiates the contact system that drives both the intrinsic pathway of coagulation, and formation of the inflammatory mediator bradykinin by the kallikrein-kinin system. Moreover, FXII facilitates receptor-mediated signalling, thereby promoting mitogenic activities, angiogenesis, and neutrophil stimulation with implications for liver diseases. Here, we summarize current knowledge on the FXII-driven contact system in liver diseases and review therapeutic approaches to target its activities during impaired liver function.
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http://dx.doi.org/10.1007/s00281-021-00876-7DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8202222PMC
June 2021

Defective NET clearance contributes to sustained FXII activation in COVID-19-associated pulmonary thrombo-inflammation.

EBioMedicine 2021 May 14;67:103382. Epub 2021 May 14.

Institute of Clinical Chemistry and Laboratory Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany. Electronic address:

Background: Coagulopathy and inflammation are hallmarks of Coronavirus disease 2019 (COVID-19) and are associated with increased mortality. Clinical and experimental data have revealed a role for neutrophil extracellular traps (NETs) in COVID-19 disease. The mechanisms that drive thrombo-inflammation in COVID-19 are poorly understood.

Methods: We performed proteomic analysis and immunostaining of postmortem lung tissues from COVID-19 patients and patients with other lung pathologies. We further compared coagulation factor XII (FXII) and DNase activities in plasma samples from COVID-19 patients and healthy control donors and determined NET-induced FXII activation using a chromogenic substrate assay.

Findings: FXII expression and activity were increased in the lung parenchyma, within the pulmonary vasculature and in fibrin-rich alveolar spaces of postmortem lung tissues from COVID-19 patients. In agreement with this, plasmaaac acafajföeFXII activation (FXIIa) was increased in samples from COVID-19 patients. Furthermore, FXIIa colocalized with NETs in COVID-19 lung tissue indicating that NETs accumulation leads to FXII contact activation in COVID-19. We further showed that an accumulation of NETs is partially due to impaired NET clearance by extracellular DNases as DNase substitution improved NET dissolution and reduced FXII activation in vitro.

Interpretation: Collectively, our study supports that the NET/FXII axis contributes to the pathogenic chain of procoagulant and proinflammatory responses in COVID-19. Targeting both NETs and FXIIa may offer a potential novel therapeutic strategy.

Funding: This study was supported by the European Union (840189), the Werner Otto Medical Foundation Hamburg (8/95) and the German Research Foundation (FR4239/1-1, A11/SFB877, B08/SFB841 and P06/KFO306).
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http://dx.doi.org/10.1016/j.ebiom.2021.103382DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8120108PMC
May 2021

Proteomics: A Tool to Study Platelet Function.

Int J Mol Sci 2021 Apr 30;22(9). Epub 2021 Apr 30.

Leibniz-Institut für Analytische Wissenschaften-ISAS-e.V, Bunsen-Kirchhoff-Straße 11, 44139 Dortmund, Germany.

Platelets are components of the blood that are highly reactive, and they quickly respond to multiple physiological and pathophysiological processes. In the last decade, it became clear that platelets are the key components of circulation, linking hemostasis, innate, and acquired immunity. Protein composition, localization, and activity are crucial for platelet function and regulation. The current state of mass spectrometry-based proteomics has tremendous potential to identify and quantify thousands of proteins from a minimal amount of material, unravel multiple post-translational modifications, and monitor platelet activity during drug treatments. This review focuses on the role of proteomics in understanding the molecular basics of the classical and newly emerging functions of platelets. including the recently described role of platelets in immunology and the development of COVID-19.The state-of-the-art proteomic technologies and their application in studying platelet biogenesis, signaling, and storage are described, and the potential of newly appeared trapped ion mobility spectrometry (TIMS) is highlighted. Additionally, implementing proteomic methods in platelet transfusion medicine, and as a diagnostic and prognostic tool, is discussed.
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http://dx.doi.org/10.3390/ijms22094776DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8125008PMC
April 2021

Plasmin-mediated Cleavage of High Molecular Weight Kininogen Contributes to Acetaminophen-Induced Acute Liver Failure.

Blood 2021 Apr 7. Epub 2021 Apr 7.

University of North Carolina at Chapel Hill, CHAPEL HILL, North Carolina, United States.

Acetaminophen (APAP)-induced liver injury is associated with activation of coagulation and fibrinolysis. In mice, both tissue factor-dependent thrombin generation and plasmin activity have been shown to promote liver injury after APAP overdose. However, the contribution of the contact and intrinsic coagulation pathways has not been investigated in this model. Mice deficient in individual factors of the contact (FXII and PK) or intrinsic coagulation (FXI) pathway were administered a hepatotoxic dose of 400 mg/kg of APAP. Neither FXII, FXI, nor prekallikrein deficiency mitigated coagulation activation or hepatocellular injury. Interestingly, despite the lack of significant changes to APAP-induced coagulation activation, markers of liver injury and inflammation were significantly reduced in APAP-challenged high molecular weight kininogen-deficient (HK-/-) mice. Protective effects of HK deficiency were not reproduced by inhibition of bradykinin-mediated signaling, whereas reconstitution of circulating levels of HK in HK-/- mice restored hepatotoxicity. Fibrinolysis activation was observed in mice after APAP administration. Western blotting, ELISA, and mass spectrometry analysis demonstrated that plasmin efficiently cleaves HK into multiple fragments in buffer or plasma. Importantly, plasminogen deficiency attenuated APAP-induced liver injury and prevented HK cleavage in the injured liver. Finally, enhanced plasmin generation and HK cleavage, in the absence of contact pathway activation, were observed in plasma of patients with acute liver failure due to APAP overdose. In summary, extrinsic, but not intrinsic pathway activation drives the thromboinflammatory pathology associated with APAP-induced liver injury in mice. Furthermore, plasmin mediated cleavage of HK contributes to hepatotoxicity in APAP-challenged mice independently of thrombin generation or bradykinin signaling.
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http://dx.doi.org/10.1182/blood.2020006198DOI Listing
April 2021

Differences in measurement of high-sensitivity troponin in an on-demand and batch-wise setting.

Eur Heart J Acute Cardiovasc Care 2020 Jul 23. Epub 2020 Jul 23.

Department of Cardiology, University Heart and Vascular Center Hamburg Eppendorf, Hamburg, Germany.

Background: Most studies assessing the diagnostic value of high-sensitivity troponin in the diagnosis of myocardial infarction used batch-wise analyses of frozen samples for high-sensitivity troponin measurements. Whether the accuracy of these batch-wise high-sensitivity troponin measurements described in diagnostic studies is comparable to clinical routine is unknown.

Methods: We enrolled 937 patients presenting with suspected myocardial infarction in this prospective cohort study. Measurements of high-sensitivity troponin I (Abbott Architect) and high-sensitivity troponin T (Roche) were performed in two settings: (a) on-demand in clinical routine using fresh blood samples; and (b) in batches using frozen blood samples from the same individuals at three timepoints (0 hours, 1 hour and 3 hours after presentation).

Results: Median troponin levels were not different between on-demand and batch-wise measurements. Troponin levels in the range of 0 to 40 ng/L showed a very high correlation between the on-demand and batch setting (Pearson correlation coefficient (r) was 0.92-0.95 for high-sensitivity troponin I and 0.96 for high-sensitivity troponin T). However, at very low troponin levels (0 to 10 ng/L) correlation between the two settings was moderate (r for high-sensitivity troponin I 0.59-0.66 and 0.65-0.69 for high-sensitivity troponin T). Application of guideline-recommended rapid diagnostic algorithms showed similar diagnostic performance with both methods.

Conclusions: Overall on-demand and batch-wise measurements of high-sensitivity troponin provided similar results, but their correlation was moderate, when focusing on very low troponin levels. The application of rapid diagnostic algorithms was safe in both settings.

Trial Registration: www.clinicaltrials.gov (NCT02355457).
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http://dx.doi.org/10.1177/2048872620924198DOI Listing
July 2020

EVL regulates VEGF receptor-2 internalization and signaling in developmental angiogenesis.

EMBO Rep 2021 02 29;22(2):e48961. Epub 2021 Jan 29.

Centre for Molecular Medicine, Institute for Vascular Signalling, Goethe University, Frankfurt am Main, Germany.

Endothelial tip cells are essential for VEGF-induced angiogenesis, but underlying mechanisms are elusive. The Ena/VASP protein family, consisting of EVL, VASP, and Mena, plays a pivotal role in axon guidance. Given that axonal growth cones and endothelial tip cells share many common features, from the morphological to the molecular level, we investigated the role of Ena/VASP proteins in angiogenesis. EVL and VASP, but not Mena, are expressed in endothelial cells of the postnatal mouse retina. Global deletion of EVL (but not VASP) compromises the radial sprouting of the vascular plexus in mice. Similarly, endothelial-specific EVL deletion compromises the radial sprouting of the vascular plexus and reduces the endothelial tip cell density and filopodia formation. Gene sets involved in blood vessel development and angiogenesis are down-regulated in EVL-deficient P5-retinal endothelial cells. Consistently, EVL deletion impairs VEGF-induced endothelial cell proliferation and sprouting, and reduces the internalization and phosphorylation of VEGF receptor 2 and its downstream signaling via the MAPK/ERK pathway. Together, we show that endothelial EVL regulates sprouting angiogenesis via VEGF receptor-2 internalization and signaling.
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http://dx.doi.org/10.15252/embr.201948961DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7857432PMC
February 2021

Genome-wide analysis of gene dosage in 24,092 individuals estimates that 10,000 genes modulate cognitive ability.

Mol Psychiatry 2021 Jan 7. Epub 2021 Jan 7.

The Hospital for Sick Children, University of Toronto, Toronto, ON, Canada.

Genomic copy number variants (CNVs) are routinely identified and reported back to patients with neuropsychiatric disorders, but their quantitative effects on essential traits such as cognitive ability are poorly documented. We have recently shown that the effect size of deletions on cognitive ability can be statistically predicted using measures of intolerance to haploinsufficiency. However, the effect sizes of duplications remain unknown. It is also unknown if the effect of multigenic CNVs are driven by a few genes intolerant to haploinsufficiency or distributed across tolerant genes as well. Here, we identified all CNVs > 50 kilobases in 24,092 individuals from unselected and autism cohorts with assessments of general intelligence. Statistical models used measures of intolerance to haploinsufficiency of genes included in CNVs to predict their effect size on intelligence. Intolerant genes decrease general intelligence by 0.8 and 2.6 points of intelligence quotient when duplicated or deleted, respectively. Effect sizes showed no heterogeneity across cohorts. Validation analyses demonstrated that models could predict CNV effect sizes with 78% accuracy. Data on the inheritance of 27,766 CNVs showed that deletions and duplications with the same effect size on intelligence occur de novo at the same frequency. We estimated that around 10,000 intolerant and tolerant genes negatively affect intelligence when deleted, and less than 2% have large effect sizes. Genes encompassed in CNVs were not enriched in any GOterms but gene regulation and brain expression were GOterms overrepresented in the intolerant subgroup. Such pervasive effects on cognition may be related to emergent properties of the genome not restricted to a limited number of biological pathways.
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http://dx.doi.org/10.1038/s41380-020-00985-zDOI Listing
January 2021

Polyanions in Coagulation and Thrombosis: Focus on Polyphosphate and Neutrophils Extracellular Traps.

Thromb Haemost 2020 Dec 11. Epub 2020 Dec 11.

Institute of Clinical Chemistry and Laboratory Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.

Neutrophil extracellular traps (NETs) and polyphosphates (polyP) have been recognized as procoagulant polyanions. This review summarizes the activities and regulation of the two procoagulant mediators and compares their functions. NETs are composed of DNA which like polyP is built of phosphate units linked by high-energy phosphoanhydride bonds. Both NETs and polyP form insoluble particulate surfaces composed of a DNA/histone meshwork or Ca-rich nanoparticles, respectively. These polyanionic molecules modulate coagulation involving an array of mechanisms and trigger thrombosis via activation of the factor XII-driven procoagulant and proinflammatory contact pathway. Here, we outline the current knowledge on NETs and polyP with respect to their procoagulant and prothrombotic nature, strategies for interference of their activities in circulation, as well as the crosstalk between these two molecules. A better understanding of the underlying, cellular mechanisms will shed light on the therapeutic potential of targeting NETs and polyP in coagulation and thrombosis.
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http://dx.doi.org/10.1055/a-1336-0526DOI Listing
December 2020

NADPH Oxidases Are Required for Full Platelet Activation In Vitro and Thrombosis In Vivo but Dispensable for Plasma Coagulation and Hemostasis.

Arterioscler Thromb Vasc Biol 2021 02 3;41(2):683-697. Epub 2020 Dec 3.

Institute of Clinical Chemistry and Laboratory Medicine, University Medical Center Hamburg-Eppendorf, Germany (R.K.M., N.W., M.H., S.K., T.R., G.P.).

Objective: Using 3KO (triple NOX [NADPH oxidase] knockout) mice (ie, NOX1/NOX2/NOX4), we aimed to clarify the role of this family of enzymes in the regulation of platelets in vitro and hemostasis in vivo. Approach and Results: 3KO mice displayed significantly reduced platelet superoxide radical generation, which was associated with impaired platelet aggregation, adhesion, and thrombus formation in response to the key agonists collagen and thrombin. A comparison with single-gene knockouts suggested that the phenotype of 3KO platelets is the combination of the effects of the genetic deletion of NOX1 and NOX2, while NOX4 does not show any significant function in platelet regulation. 3KO platelets displayed significantly higher levels of cGMP-a negative platelet regulator that activates PKG (protein kinase G). The inhibition of PKG substantially but only partially rescued the defective phenotype of 3KO platelets, which are responsive to both collagen and thrombin in the presence of the PKG inhibitors KT5823 or Rp-8-pCPT-cGMPs, but not in the presence of the NOS (NO synthase) inhibitor L-NG-monomethyl arginine. In vivo, triple NOX deficiency protected against ferric chloride-driven carotid artery thrombosis and experimental pulmonary embolism, while hemostasis tested in a tail-tip transection assay was not affected. Procoagulatory activity of platelets (ie, phosphatidylserine surface exposure) and the coagulation cascade in platelet-free plasma were normal.

Conclusions: This study indicates that inhibiting NOXs has strong antithrombotic effects partially caused by increased intracellular cGMP but spares hemostasis. NOXs are, therefore, pharmacotherapeutic targets to develop new antithrombotic drugs without bleeding side effects.
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http://dx.doi.org/10.1161/ATVBAHA.120.315565DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7837688PMC
February 2021

Cell-autonomous hepatocyte-specific GP130 signaling is sufficient to trigger a robust innate immune response in mice.

J Hepatol 2021 Feb 25;74(2):407-418. Epub 2020 Sep 25.

Institute of Biochemistry, Christian-Albrechts-University Kiel, Germany. Electronic address:

Background & Aims: Interleukin (IL)-6 cytokine family members contribute to inflammatory and regenerative processes. Engagement of the signaling receptor subunit gp130 is common to almost all members of the family. In the liver, all major cell types respond to IL-6-type cytokines, making it difficult to delineate cell type-specific effects. We therefore generated mouse models for liver cell type-specific analysis of IL-6 signaling.

Methods: We produced mice with a Cre-inducible expression cassette encoding a designed pre-dimerized constitutive active gp130 variant. We bred these mice to different Cre-drivers to induce transgenic gp130 signaling in distinct liver cell types: hepatic stellate cells, cholangiocytes/liver progenitor cells or hepatocytes. We phenotyped these mice using multi-omics approaches, immunophenotyping and a bacterial infection model.

Results: Hepatocyte-specific gp130 activation led to the upregulation of innate immune system components, including acute-phase proteins. Consequently, we observed peripheral mobilization and recruitment of myeloid cells to the liver. Hepatic myeloid cells, including liver-resident Kupffer cells were instructed to adopt a bactericidal phenotype which ultimately conferred enhanced resistance to bacterial infection in these mice. We demonstrate that persistent hepatocyte-specific gp130 activation resulted in amyloid A amyloidosis in aged mice. In contrast, we did not observe overt effects of hepatic stellate cell- or cholangiocyte/liver progenitor cell-specific transgenic gp130 signaling.

Conclusions: Hepatocyte-specific gp130 activation alone is sufficient to trigger a robust innate immune response in the absence of NF-κB activation. We therefore conclude that gp130 engagement, e.g. by IL-6 trans-signaling, represents a safe-guard mechanism in innate immunity.

Lay Summary: Members of the interleukin-6 cytokine family signal via the receptor subunit gp130 and are involved in multiple processes in the liver. However, as several liver cell types respond to interleukin-6 family cytokines, it is difficult to delineate cell type-specific effects. Using a novel mouse model, we provide evidence that hepatocyte-specific gp130 activation is sufficient to trigger a robust systemic innate immune response.
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http://dx.doi.org/10.1016/j.jhep.2020.09.021DOI Listing
February 2021

Xenotropic and polytropic retrovirus receptor 1 regulates procoagulant platelet polyphosphate.

Blood 2021 03;137(10):1392-1405

Institute of Clinical Chemistry and Laboratory Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.

Polyphosphate is a procoagulant inorganic polymer of linear-linked orthophosphate residues. Multiple investigations have established the importance of platelet polyphosphate in blood coagulation; however, the mechanistic details of polyphosphate homeostasis in mammalian species remain largely undefined. In this study, xenotropic and polytropic retrovirus receptor 1 (XPR1) regulated polyphosphate in platelets and was implicated in thrombosis in vivo. We used bioinformatic analyses of omics data to identify XPR1 as a major phosphate transporter in platelets. XPR1 messenger RNA and protein expression inversely correlated with intracellular polyphosphate content and release. Pharmacological interference with XPR1 activity increased polyphosphate stores, led to enhanced platelet-driven coagulation, and amplified thrombus formation under flow via the polyphosphate/factor XII pathway. Conditional gene deletion of Xpr1 in platelets resulted in polyphosphate accumulation, accelerated arterial thrombosis, and augmented activated platelet-driven pulmonary embolism without increasing bleeding in mice. These data identify platelet XPR1 as an integral regulator of platelet polyphosphate metabolism and reveal a fundamental role for phosphate homeostasis in thrombosis.
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http://dx.doi.org/10.1182/blood.2019004617DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7955403PMC
March 2021

Comparison of acetylsalicylic acid and clopidogrel non-responsiveness assessed by light transmittance aggregometry and PFA-100® in patients undergoing neuroendovascular procedures.

Clin Chem Lab Med 2020 Aug 31;59(2):383-392. Epub 2020 Aug 31.

Department of Oncology/Hematology and BMT with Section of Pneumology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.

Objectives: Dual platelet inhibition is commonly used for prevention of cardiovascular events in patients undergoing neuroendovascular procedures. Non-responsiveness to platelet inhibitors may be associated with adverse outcomes. The aim of this study was to evaluate the reliability of the platelet function analyzer PFA-100® in comparison to light transmittance aggregometry (LTA) for monitoring clopidogrel and acetylsalicylic acid (ASA) non-responsiveness in a cohort of patients treated for intracranial aneurysm or cranial artery stenosis.

Methods: Non-responsiveness to clopidogrel and ASA was assessed by LTA using adenosine diphosphate (ADP) and arachidonic acid and by PFA-100® with the ADP/prostaglandin E1 (PGE1) and collagen/epinephrine cartridges, respectively.

Results: A total of 203 patients (145 females; median age, 57 years) were analyzed. Agreement between the two tests was poor for clopidogrel non-responsiveness (ƙ=0.19) and not better than chance for ASA non-responsiveness (ƙ=0.01). Clopidogrel non-responsiveness by LTA and PFA-100® was associated with higher von Willebrand factor antigen and activity levels. ADP-induced platelet disaggregation was lower in patients with clopidogrel non-responsiveness as assessed by PFA-100®. Clopidogrel non-responsiveness by LTA was associated with a higher prevalence of diabetes and a higher body mass index (BMI). Adverse outcomes (death, thromboembolism, or in-stent thrombosis) occurred in 13% (n=26) of all patients independently of ASA and clopidogrel non-responsiveness as assessed by both devices.

Conclusions: Our results show that LTA and PFA-100® are not interchangeable in the assessment of ASA and clopidogrel non-responsiveness in patients undergoing neuroendovascular interventions.
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http://dx.doi.org/10.1515/cclm-2020-0737DOI Listing
August 2020

Differences in measurement of high-sensitivity troponin in an on-demand and batch-wise setting.

Eur Heart J Acute Cardiovasc Care 2020 Jul 23:2048872620924198. Epub 2020 Jul 23.

Department of Cardiology, University Heart and Vascular Center Hamburg Eppendorf, Hamburg, Germany.

Background: Most studies assessing the diagnostic value of high-sensitivity troponin in the diagnosis of myocardial infarction used batch-wise analyses of frozen samples for high-sensitivity troponin measurements. Whether the accuracy of these batch-wise high-sensitivity troponin measurements described in diagnostic studies is comparable to clinical routine is unknown.

Methods: We enrolled 937 patients presenting with suspected myocardial infarction in this prospective cohort study. Measurements of high-sensitivity troponin I (Abbott Architect) and high-sensitivity troponin T (Roche) were performed in two settings: (a) on-demand in clinical routine using fresh blood samples; and (b) in batches using frozen blood samples from the same individuals at three timepoints (0 hours, 1 hour and 3 hours after presentation).

Results: Median troponin levels were not different between on-demand and batch-wise measurements. Troponin levels in the range of 0 to 40 ng/L showed a very high correlation between the on-demand and batch setting (Pearson correlation coefficient () was 0.92-0.95 for high-sensitivity troponin I and 0.96 for high-sensitivity troponin T). However, at very low troponin levels (0 to 10 ng/L) correlation between the two settings was moderate ( for high-sensitivity troponin I 0.59-0.66 and 0.65-0.69 for high-sensitivity troponin T). Application of guideline-recommended rapid diagnostic algorithms showed similar diagnostic performance with both methods.

Conclusions: Overall on-demand and batch-wise measurements of high-sensitivity troponin provided similar results, but their correlation was moderate, when focusing on very low troponin levels. The application of rapid diagnostic algorithms was safe in both settings. www.clinicaltrials.gov (NCT02355457).
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http://dx.doi.org/10.1177/2048872620924198DOI Listing
July 2020

In-depth characterization of monocyte subsets during the course of healthy pregnancy.

J Reprod Immunol 2020 09 23;141:103151. Epub 2020 May 23.

Heinrich Pette Institute, Leibniz Institute for Experimental Virology, Martinistraße 52, Hamburg 20251, Germany. Electronic address:

Pregnancy represents an immunological challenge for the maternal immune system. Pregnancy augments innate immune responses, and particularly monocytes contribute to maintaining the balance between pro- and anti-inflammatory immune responses required for the successful sequence of distinct immunological phases throughout pregnancy. Nonetheless, studies that focus on the heterogeneity of monocytes and analyze the alteration of monocyte subsets in a longitudinal approach throughout healthy pregnancies have remained scarce. In this study, we characterized the gradual phenotypic changes of monocyte subsets and the secretory potential of bulk monocytes in peripheral blood mononuclear cells of healthy pregnant women from a population-based prospective birth cohort study. Blood samples at predefined time points were analyzed using flow cytometry for in-depth characterization of monocyte subsets, which confirmed a shift from classical towards intermediate monocytes throughout pregnancy. Principal component analysis revealed characteristic phenotypic changes on monocyte subsets, especially on the intermediate monocyte subset, throughout pregnancy. Pregnancy-related hormones were measured in serum and β-human chorionic gonadotropin levels were significantly associated with expression of CD11b, CD116 and CCR2 on monocyte subsets. TLR4 and TLR7/8 stimulation of monocytes furthermore showed reduced polycytokine production towards the end of pregnancy. These data provide a comprehensive overview of phenotypic changes and secretory potential of monocytes in healthy pregnant women and establish a selective contribution of different monocyte subsets to healthy pregnancy. The results from this study therefore build a basis for future comparisons and evaluation of women with adverse pregnancy outcomes.
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http://dx.doi.org/10.1016/j.jri.2020.103151DOI Listing
September 2020

Testosterone Protects Against Severe Influenza by Reducing the Pro-Inflammatory Cytokine Response in the Murine Lung.

Front Immunol 2020 22;11:697. Epub 2020 Apr 22.

Department Viral Zoonoses - One Health, Heinrich Pette Institute, Leibniz Institute for Experimental Virology, Hamburg, Germany.

Influenza A virus pathogenesis may differ between men and women. The 2009 H1N1 influenza pandemic resulted in more documented hospitalizations in women compared to men. In this study, we analyzed the impact of male sex hormones on pandemic 2009 H1N1 influenza A virus disease outcome. In a murine infection model, we could mimic the clinical findings with female mice undergoing severe and even fatal 2009 H1N1 influenza compared to male mice. Treatment of female mice with testosterone could rescue the majority of mice from lethal influenza. Improved disease outcome in testosterone treated female mice upon 2009 H1N1 influenza A virus infection did not affect virus titers in the lung compared to carrier-treated females. However, reduction in IL-1β cytokine expression levels strongly correlated with reduced lung damage and improved influenza disease outcome in female mice upon testosterone treatment. In contrast, influenza disease outcome was not affected between castrated male mice and non-castrated controls. Here, influenza infection resulted in reduction of testosterone expression in male mice. These findings show that testosterone has protective functions on the influenza infection course. However, 2009 H1N1 influenza viruses seem to have evolved yet unknown mechanisms to reduce testosterone expression in males. These data will support future antiviral strategies to treat influenza taking sex-dependent immunopathologies into consideration.
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http://dx.doi.org/10.3389/fimmu.2020.00697DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7216738PMC
March 2021

LPS-induced expression and release of monocyte tissue factor in patients with haemophilia.

Ann Hematol 2020 Jul 19;99(7):1531-1542. Epub 2020 May 19.

Department of Haematology and Oncology, University Cancer Centre Hamburg (UCCH), University Medical Centre Eppendorf, Hamburg, Germany.

In haemophilia, thrombin generation and fibrin deposition upon vascular injury critically depend on the tissue factor (TF)-driven coagulation pathway. TF expression by monocytes/macrophages and circulating microvesicles contributes to haemostasis, thrombosis and inflammation. Inflammation is a hallmark of blood-induced joint disease. The aim of this study is to correlate TF production by whole-blood monocytes with inflammatory markers and clinical parameters in patients with moderate-to-severe haemophilia A or B (n = 43) in comparison to healthy males (n = 23). Monocyte TF antigen and microvesicle-associated TF procoagulant activity (MV TF PCA) were measured immediately after blood draw (baseline) and following incubation of whole blood with buffer or lipopolysaccharide (LPS) using two-colour flow cytometry and chromogenic FXa generation assay, respectively. Patients with HIV or uncontrolled HBV/HCV infections were excluded. TF was hardly detectable and not different in baseline and buffer-treaded samples from both groups. Stimulation with LPS, however, induced monocyte TF production, with increased TF-specific mean fluorescence intensity (P = 0.08) and MV TF PCA (P < 0.05) in patients compared to controls. Patients also had elevated hs-CRP and IL-6 serum levels (P < 0.001), which correlated with LPS-induced TF parameters. Further exploratory analyses revealed that the presence of systemic (low-grade) inflammation and boosted LPS-induced monocyte TF production were mainly restricted to patients with clinically controlled HBV and/or HCV infection (n = 16), who were older and also had a significantly worse orthopaedic joint score than patients with no history of viral hepatitis (P < 0.01). Our study delineates a previously unrecognised link between systemic inflammation and inducible monocyte TF production in patients with haemophilia A or B.
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http://dx.doi.org/10.1007/s00277-020-04075-6DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7316670PMC
July 2020

Red blood cell microvesicles activate the contact system, leading to factor IX activation via 2 independent pathways.

Blood 2020 03;135(10):755-765

Department of Medicine.

Storage lesion-induced, red cell-derived microvesicles (RBC-MVs) propagate coagulation by supporting the assembly of the prothrombinase complex. It has also been reported that RBC-MVs initiate coagulation via the intrinsic pathway. To elucidate the mechanism(s) of RBC-MV-induced coagulation activation, the ability of storage lesion-induced RBC-MVs to activate each zymogen of the intrinsic pathway was assessed in a buffer system. Simultaneously, the thrombin generation (TG) assay was used to assess their ability to initiate coagulation in plasma. RBC-MVs directly activated factor XII (FXII) or prekallikrein, but not FXI or FIX. RBC-MVs initiated TG in normal pooled plasma and in FXII- or FXI-deficient plasma, but not in FIX-deficient plasma, suggesting an alternate pathway that bypasses both FXII and FXI. Interestingly, RBC-MVs generated FIXa in a prekallikrein-dependent manner. Similarly, purified kallikrein activated FIX in buffer and initiated TG in normal pooled plasma, as well as FXII- or FXI-deficient plasma, but not FIX-deficient plasma. Dual inhibition of FXIIa by corn trypsin inhibitor and kallikrein by soybean trypsin inhibitor was necessary for abolishing RBC-MV-induced TG in normal pooled plasma, whereas kallikrein inhibition alone was sufficient to abolish TG in FXII- or FXI-deficient plasma. Heating RBC-MVs at 60°C for 15 minutes or pretreatment with trypsin abolished TG, suggesting the presence of MV-associated proteins that are essential for contact activation. In summary, RBC-MVs activate both FXII and prekallikrein, leading to FIX activation by 2 independent pathways: the classic FXIIa-FXI-FIX pathway and direct kallikrein activation of FIX. These data suggest novel mechanisms by which RBC transfusion mediates inflammatory and/or thrombotic outcomes.
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http://dx.doi.org/10.1182/blood.2019001643DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7059516PMC
March 2020

A Systems-Based Map of Human Brain Cell-Type Enriched Genes and Malignancy-Associated Endothelial Changes.

Cell Rep 2019 11;29(6):1690-1706.e4

Science for Life Laboratory, Department of Protein Science, Royal Institute of Technology (KTH), 171 21 Stockholm, Sweden; K.G. Jebsen Thrombosis Research and Expertise Centre, Department of Clinical Medicine, The Arctic University of Norway, 9019 Tromsø, Norway; Institute for Clinical Chemistry and Laboratory Medicine, University Medical Centre Hamburg-Eppendorf, 20246 Hamburg, Germany; Clinical Chemistry and Blood Coagulation Research, Department of Molecular Medicine and Surgery, Karolinska Institute, 171 76 Stockholm, Sweden. Electronic address:

Changes in the endothelium of the cerebral vasculature can contribute to inflammatory, thrombotic, and malignant disorders. The importance of defining cell-type-specific genes and their modification in disease is increasingly recognized. Here, we develop a bioinformatics-based approach to identify normal brain cell-enriched genes, using bulk RNA sequencing (RNA-seq) data from 238 normal human cortex samples from 2 independent cohorts. We compare endothelial cell-enriched gene profiles with astrocyte, oligodendrocyte, neuron, and microglial cell profiles. Endothelial changes in malignant disease are explored using RNA-seq data from 516 lower-grade gliomas and 401 glioblastomas. Lower-grade gliomas appear to be an "endothelial intermediate" between normal brain and glioblastoma. We apply our method for the prediction of glioblastoma-specific endothelial biomarkers, providing potential diagnostic or therapeutic targets. In summary, we provide a roadmap of endothelial cell identity in normal and malignant brain, using a method developed to resolve bulk RNA-seq into constituent cell-type-enriched profiles.
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http://dx.doi.org/10.1016/j.celrep.2019.09.088DOI Listing
November 2019

Roles of Factor XII in Innate Immunity.

Front Immunol 2019 22;10:2011. Epub 2019 Aug 22.

Section of Hematology-Oncology, Department of Medicine, Louis Stokes Cleveland Veterans Administration Medical Center, VA Northeast Ohio Healthcare System, Cleveland, OH, United States.

Factor XII (FXII) is the zymogen of serine protease, factor XIIa (FXIIa). FXIIa enzymatic activities have been extensively studied and FXIIa inhibition is emerging as a promising target to treat or prevent thrombosis without creating a hemostatic defect. FXII and plasma prekallikrein reciprocally activate each other and result in liberation of bradykinin. Due to its unique structure among coagulation factors, FXII exerts mitogenic activity in endothelial and smooth muscle cells, indicating that zymogen FXII has activities independent of its protease function. A growing body of evidence has revealed that both FXII and FXIIa upregulate neutrophil functions, contribute to macrophage polarization and induce T-cell differentiation. , these signaling activities contribute to host defense against pathogens, mediate the development of neuroinflammation, influence wound repair and may facilitate cancer maintenance and progression. Here, we review the roles of FXII in innate immunity as they relate to non-sterile and sterile immune responses.
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http://dx.doi.org/10.3389/fimmu.2019.02011DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6713930PMC
September 2020

Nomenclature of factor XI and the contact system.

J Thromb Haemost 2019 12 13;17(12):2216-2219. Epub 2019 Aug 13.

Department of Molecular and Cellular Hemostasis, Sanquin Research, Amsterdam, the Netherlands.

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http://dx.doi.org/10.1111/jth.14595DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6893083PMC
December 2019

International Society on Thrombosis and Haemostasis core curriculum project: Core competencies in laboratory thrombosis and hemostasis.

J Thromb Haemost 2019 11 5;17(11):1848-1859. Epub 2019 Sep 5.

Primrose Lane Medical Centre, NHS Fife, Rosyth, UK.

Background: Laboratory analyses of blood samples are essential for diagnostics and therapy monitoring of patients with bleeding and thromboembolic diseases. Following publication of the core curriculum for clinical thrombosis and hemostasis, the International Society on Thrombosis and Haemostasis (ISTH) recognized that thrombosis and hemostasis laboratory specialists require distinct competencies that differ from medical doctors working clinically with patients. To address this gap the ISTH formed a working group of international hemostasis and thrombosis laboratory specialists to develop an evidence-based core curriculum for laboratory specialists.

Objective: This research sought consensus from the international community on core competencies required for laboratory specialists in thrombosis and hemostasis.

Methods: A draft list of 64 competencies was developed and an online stakeholder survey was circulated electronically to 15 302 ISTH members and contacts in the wider international community. The results were analyzed and used to develop the final approved core curriculum.

Results: Three hundred and thirty responses contained meaningful data, with broad international representation of specialists. No draft competencies were excluded, and 58 were rated as "does" or "shows how." The Leik measure of consensus for most competences was "moderate" (n = 30) or "fair" (n = 32).

Conclusions: The development of an international core curriculum for laboratory specialists provides a foundation for the development and enhancement of education and quality management of the laboratory. Although there is no formal designation for laboratory specialists, international governing bodies and regulatory organizations are encouraged to consider the diagnostic core curriculum for development and accreditation of more standardized educational programs and formal assessment across jurisdictions.
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http://dx.doi.org/10.1111/jth.14601DOI Listing
November 2019

Design and characterization of α1-antitrypsin variants for treatment of contact system-driven thromboinflammation.

Blood 2019 11;134(19):1658-1669

Department of Clinical Chemistry and Haematology, University Medical Center Utrecht, Utrecht University, Utrecht, The Netherlands.

The contact system produces the inflammatory peptide bradykinin and contributes to experimental thrombosis. C1 esterase-inhibitor (C1INH) deficiency or gain-of-function mutations in factor XII (FXII) cause hereditary angioedema, a life-threatening tissue swelling disease. C1INH is a relatively weak contact system enzyme inhibitor. Although α1-antitrypsin (α1AT) does not naturally inhibit contact system enzymes, a human mutation (M358R; α1AT-Pittsburgh) changes it into a powerful broad-spectrum enzyme inhibitor. It blocks the contact system, but also thrombin and activated protein C (APC), making it an unattractive candidate for therapeutic contact system blockade. We adapted the reactive center loop of α1AT-Pittsburgh (AIPR/S) to overcome these obstacles. Two α1AT variants (SMTR/S and SLLR/S) strongly inhibit plasma kallikrein, activated FXII, and plasmin. α1AT-SMTR/S no longer inhibits thrombin, but residually inhibits APC. In contrast, α1AT-SLLR/S residually inhibits thrombin, but no longer APC. Additional modification at the P1' position (S→V) eliminates residual inhibition of thrombin and APC for both variants, while retaining their properties as contact system inhibitors. Both α1AT-SMTR/V and -SLLR/V are superior to C1INH in reducing bradykinin production in plasma. Owing to their capacity to selectively block contact system-driven coagulation, both variants block vascular occlusion in an in vivo model for arterial thrombosis. Furthermore, both variants block acute carrageenan-induced tissue edema in mice. Finally, α1AT-SLLR/V, our most powerful candidate, suppresses epithelial leakage of the gut in a mouse model of colitis. Our findings confirm that redesign of α1AT strongly alters its inhibitory behavior and can be used for the treatment of contact system-mediated thrombosis and inflammation.
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http://dx.doi.org/10.1182/blood.2019000481DOI Listing
November 2019

Application of High-Sensitivity Troponin in Suspected Myocardial Infarction.

N Engl J Med 2019 06;380(26):2529-2540

From the University Heart Center Hamburg (J.T.N., R.T., F.O., N.A.S., T.Z., D.W., S.B.), German Center for Cardiovascular Research (DZHK) Partner Site Hamburg-Kiel-Lübeck (J.T.N., N.A.S., T.Z., D.W., S.B.), and the Institute of Clinical Chemistry and Laboratory Medicine, University Medical Center Hamburg-Eppendorf (T.R.), Hamburg, the Department of Cardiology, Heidelberg University Hospital (M.M.-H., H.A.K., E.G.), and DZHK Partner Site Heidelberg-Mannheim (M.M.-H., H.A.K., E.G.), Heidelberg, Cardiology I (T.G., T.M.) and Preventive Cardiology and Preventive Medicine (P.W.), Center for Cardiology, and the Center for Thrombosis and Hemostasis (P.W.), University Medical Center of Johannes Gutenberg University Mainz, and the Institute of Clinical Chemistry and Laboratory Medicine, University Medical Center Mainz (K.J.L.), Mainz, DZHK Partner Site Rhine-Main and the Department of Cardiology, Kerckhoff Heart and Thorax Center, Bad Nauheim (C.L., C.H., T.K.), the Department of Cardiology, Justus Liebig University of Giessen and Marburg, Giessen (C.L., C.H.), the Department of Cardiology, Charité Universitätsmedizin Berlin, Campus Benjamin Franklin, Berlin Institute of Health, and DZHK Partner Site Berlin, Berlin (U.L.), and the Institute of Epidemiology, Helmholtz Zentrum, German Research Center for Environmental Health (B.T., A.P.), and DZHK Partner Site Munich Heart Alliance (A.P.), Munich - all in Germany; the Cardiovascular Research Institute Basel and the Department of Cardiology, University Hospital Basel, University of Basel, Basel, Switzerland (R.T., J.B., T.N., P.B., C.M.); the British Heart Foundation Centre for Cardiovascular Science (A.R.C., A.S.V.S., A.A., N.L.M.) and the Usher Institute of Population Health Sciences and Informatics (A.S.V.S., N.L.M.), University of Edinburgh, Edinburgh, the University of Manchester and Manchester University Foundation Trust, Manchester (N.M., R. Body), U.K. Clinical Research Collaboration for Public Health, Queens University of Belfast, Belfast (F.K.), and the Cardiovascular Epidemiology Unit, Institute of Cardiovascular Research, University of Dundee, Dundee (H.T.-P.) - all in the United Kingdom; the Department of Internal and Emergency Medicine, Lund University, Skåne University Hospital, Lund (A.M., U.E.), the Department of Clinical Sciences, Danderyd University Hospital, Karolinska Institutet, Stockholm (T. Jernberg), the Department of Public Health and Clinical Medicine, and Heart Center, Cardiology, Umeå University, Umeå (S. Söderberg), and the Department of Medical Sciences and Uppsala Clinical Research Center, Uppsala University, Uppsala (B.L.) - all in Sweden; the Department of Medicine, University of Otago Christchurch, and Emergency Department, Christchurch Hospital, Christchurch, New Zealand (J.W.P., R.W.T., M.T.); the Departments of Emergency Medicine (J.G., L.A.C.) and Cardiology (W.P.), Royal Brisbane and Women's Hospital, Herston, QLD, and the Institute of Health and Biomedical Innovation, Queensland University of Technology, Kelvin Grove (J.G., W.P., L.A.C.) - all in Australia; the National Institute for Health and Welfare, Helsinki, Finland (V.S., K.K.); the Department of Epidemiology and Prevention, Istituto di Ricovero e Cura a Carattere Scientifico Neuromed, Pozzilli (L.I.), the Department of Medicine and Surgery, Research Center in Epidemiology and Preventive Medicine, University of Insubria, Varese (L.I., M.M.F., R. Borchini), and the Department of Cardiovascular, Dysmetabolic, and Aging-Associated Diseases, National Institutes of Health, Rome (S.G.) - all in Italy; the Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen (T. Jørgensen), the Research Center for Prevention and Health, Capital Region of Denmark, Glostrup (T. Jørgensen), and the Medical Faculty, Aalborg University, Aalborg (T. Jørgensen) - all in Denmark; the Catalan Department of Health, Barcelona (S. Sans); and the Division of Emergency Medicine (A.W.) and the Department of Pathology and Molecular Medicine (P.A.K.), McMaster University, Hamilton, ON, Canada.

Background: Data regarding high-sensitivity troponin concentrations in patients presenting to the emergency department with symptoms suggestive of myocardial infarction may be useful in determining the probability of myocardial infarction and subsequent 30-day outcomes.

Methods: In 15 international cohorts of patients presenting to the emergency department with symptoms suggestive of myocardial infarction, we determined the concentrations of high-sensitivity troponin I or high-sensitivity troponin T at presentation and after early or late serial sampling. The diagnostic and prognostic performance of multiple high-sensitivity troponin cutoff combinations was assessed with the use of a derivation-validation design. A risk-assessment tool that was based on these data was developed to estimate the risk of index myocardial infarction and of subsequent myocardial infarction or death at 30 days.

Results: Among 22,651 patients (9604 in the derivation data set and 13,047 in the validation data set), the prevalence of myocardial infarction was 15.3%. Lower high-sensitivity troponin concentrations at presentation and smaller absolute changes during serial sampling were associated with a lower likelihood of myocardial infarction and a lower short-term risk of cardiovascular events. For example, high-sensitivity troponin I concentrations of less than 6 ng per liter and an absolute change of less than 4 ng per liter after 45 to 120 minutes (early serial sampling) resulted in a negative predictive value of 99.5% for myocardial infarction, with an associated 30-day risk of subsequent myocardial infarction or death of 0.2%; a total of 56.5% of the patients would be classified as being at low risk. These findings were confirmed in an external validation data set.

Conclusions: A risk-assessment tool, which we developed to integrate the high-sensitivity troponin I or troponin T concentration at emergency department presentation, its dynamic change during serial sampling, and the time between the obtaining of samples, was used to estimate the probability of myocardial infarction on emergency department presentation and 30-day outcomes. (Funded by the German Center for Cardiovascular Research [DZHK]; ClinicalTrials.gov numbers, NCT00470587, NCT02355457, NCT01852123, NCT01994577, and NCT03227159; and Australian New Zealand Clinical Trials Registry numbers, ACTRN12611001069943, ACTRN12610000766011, ACTRN12613000745741, and ACTRN12611000206921.).
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http://dx.doi.org/10.1056/NEJMoa1803377DOI Listing
June 2019

Polyphosphate as a Target for Interference With Inflammation and Thrombosis.

Front Med (Lausanne) 2019 12;6:76. Epub 2019 Apr 12.

Institute of Clinical Chemistry and Laboratory Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.

Activated platelets and mast cells expose the inorganic polymer, polyphosphate (polyP) on their surfaces. PolyP initiates procoagulant and proinflammatory reactions and the polymer has been recognized as a therapeutic target for interference with blood coagulation and vascular hyperpermeability. PolyP content and chain length depend on the specific cell type and energy status, which may affect cellular functions. PolyP metabolism has mainly been studied in bacteria and yeast, but its roles in eukaryotic cells and mammalian systems have remained enigmatic. In this review, we will present an overview of polyP functions, focusing on intra- and extracellular roles of the polymer and discuss open questions that emerge from the current knowledge on polyP regulation.
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http://dx.doi.org/10.3389/fmed.2019.00076DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6499166PMC
April 2019

Mouse venous thrombosis upon silencing of anticoagulants depends on tissue factor and platelets, not FXII or neutrophils.

Blood 2019 05 21;133(19):2090-2099. Epub 2019 Mar 21.

Einthoven Laboratory for Vascular and Regenerative Medicine and.

Tissue factor, coagulation factor XII, platelets, and neutrophils are implicated as important players in the pathophysiology of (experimental) venous thrombosis (VT). Their role became evident in mouse models in which surgical handlings were required to provoke VT. Combined inhibition of the natural anticoagulants antithrombin () and protein C () using small interfering RNA without additional triggers also results in a venous thrombotic phenotype in mice, most notably with vessel occlusion in large veins of the head. VT is fatal but is fully rescued by thrombin inhibition. In the present study, we used this VT mouse model to investigate the involvement of tissue factor, coagulation factor XII, platelets, and neutrophils. Antibody-mediated inhibition of tissue factor reduced the clinical features of VT, the coagulopathy in the head, and fibrin deposition in the liver. In contrast, genetic deficiency in, and small interfering RNA-mediated depletion of, coagulation factor XII did not alter VT onset, severity, or thrombus morphology. Antibody-mediated depletion of platelets fully abrogated coagulopathy in the head and liver fibrin deposition. Although neutrophils were abundant in thrombotic lesions, depletion of circulating Ly6G-positive neutrophils did not affect onset, severity, thrombus morphology, or liver fibrin deposition. In conclusion, VT after inhibition of antithrombin and protein C is dependent on the presence of tissue factor and platelets but not on coagulation factor XII and circulating neutrophils. This study shows that distinct procoagulant pathways operate in mouse VT, dependent on the triggering stimulus.
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http://dx.doi.org/10.1182/blood-2018-06-853762DOI Listing
May 2019