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Clinical and Applied... Oct 2015Acute traumatic coagulopathy (ATC) is commonly seen among patients with severe injury and will lead to uncontrolled bleeding diathesis, which is an important contributor... (Review)
Review
Acute traumatic coagulopathy (ATC) is commonly seen among patients with severe injury and will lead to uncontrolled bleeding diathesis, which is an important contributor to trauma death. During the past 10 years, the understanding of the mechanism causing ATC has changed rapidly. The mechanisms for ATC are complicated. To date, the possible mechanisms include activation of protein C, shedding of endothelial glycocalyx, catecholamine release, platelet dysfunction, primary, and secondary fibrinolysis, with tissue injury and hypoperfusion as the triggers. Classic factors such as dilution, acidosis, and hypothermia can further aggravate the coagulopathy. Inflammation may have a potential effect on the onset and prognosis of ATC. With the aid of diagnostic device, the outcome can be improved through early and customized treatment. Antifibrinolytics such as tranexamic acid has some benefits in patients with bleeding trauma, especially in the early time. This review presents the current understanding of ATC mechanisms and management.
Topics: Acute Disease; Animals; Catecholamines; Disseminated Intravascular Coagulation; Endothelium, Vascular; Female; Fibrinolysis; Glycocalyx; Humans; Male; Protein C; Wounds and Injuries
PubMed: 24363215
DOI: 10.1177/1076029613516190 -
International Journal of Molecular... Nov 20223K3A-Activated Protein C (APC) is a recombinant variant of the physiological anticoagulant APC with pleiotropic cytoprotective properties albeit without the bleeding...
3K3A-Activated Protein C (APC) is a recombinant variant of the physiological anticoagulant APC with pleiotropic cytoprotective properties albeit without the bleeding risks. The anti-inflammatory activities of 3K3A-APC were demonstrated in multiple preclinical injury models, including various neurological disorders. We determined the ability of 3K3A-APC to inhibit ocular inflammation in a murine model of lipopolysaccharide (LPS)-induced uveitis. Leukocyte recruitment, microglia activation, NLRP3 inflammasome and IL-1β levels were assessed using flow cytometry, retinal cryosection histology, retinal flatmount immunohistochemistry and vascular imaging, with and without 3K3A-APC treatment. LPS triggered robust inflammatory cell recruitment in the posterior chamber. The 3K3A-APC treatment significantly decreased leukocyte numbers and inhibited leukocyte extravasation from blood vessels into the retinal parenchyma to a level similar to controls. Resident microglia, which underwent an inflammatory transition following LPS injection, remained quiescent in eyes treated with 3K3A-APC. An inflammation-associated increase in retinal thickness, observed in LPS-injected eyes, was diminished by 3K3A-APC treatment, suggesting its clinical relevancy. Finally, 3K3A-APC treatment inhibited inflammasome activation, determined by lower levels of NLRP3 and its downstream effector IL-1β. Our results highlight the anti-inflammatory properties of 3K3A-APC in ocular inflammation and suggest its potential use as a novel treatment for retinal diseases associated with inflammation.
Topics: Animals; Mice; Inflammasomes; Inflammation; Lipopolysaccharides; Microglia; NLR Family, Pyrin Domain-Containing 3 Protein; Protein C; Eye Diseases
PubMed: 36430674
DOI: 10.3390/ijms232214196 -
The Journal of Maternal-fetal &... Dec 2023Inflammation is associated with many disorders of preterm infants including periventricular leukomalacia, chronic lung disease, and necrotizing enterocolitis. Activated...
BACKGROUND
Inflammation is associated with many disorders of preterm infants including periventricular leukomalacia, chronic lung disease, and necrotizing enterocolitis. Activated protein c (APC) has shown positive immunomodulatory effects.
OBJECTIVES
We aimed to study neutrophil and monocyte function in response to lipopolysaccharide (LPS) and APC stimulation in preterm infants <32 weeks gestation over the first week of life compared to neonatal and adult controls.
METHODS
Peripheral blood was taken on day 1, 3, and 7 and stimulated with LPS in the absence or presence of APC. Expression of toll-like receptor 4 (TLR4) and CD11b and reactive oxygen intermediate (ROI) release from neutrophils and monocytes was examined by flow cytometry.
RESULTS
LPS induced neutrophil ROI in adults and preterm infants and was significantly reduced by APC. Baseline and LPS-induced monocyte ROI production in preterm neonates was increased compared to adult and term controls. Neutrophil TLR4 baseline expression was higher in term controls compared to preterm infants.
CONCLUSION
Increased systemic ROI release in preterm infants may mediate tissue damage, ROI was reduced by APC. However, due to the high risk of hemorrhage further examination of APC mutant forms with anti-inflammatory but decreased anticoagulant properties is merited.
Topics: Adult; Infant; Infant, Newborn; Humans; Infant, Premature; Neutrophils; Monocytes; Protein C; Toll-Like Receptor 4; Lipopolysaccharides
PubMed: 36935364
DOI: 10.1080/14767058.2023.2183467 -
Frontiers in Immunology 2021Sepsis is defined as a life-threatening organ dysfunction caused by a dysregulated host response to infection and is associated with high morbidity and mortality.... (Review)
Review
Sepsis is defined as a life-threatening organ dysfunction caused by a dysregulated host response to infection and is associated with high morbidity and mortality. Circulating histones (CHs), a group of damage-associated molecular pattern molecules mainly derived from neutrophil extracellular traps, play a crucial role in sepsis by mediating inflammation response, organ injury and death through Toll-like receptors or inflammasome pathways. Herein, we first elucidate the molecular mechanisms of histone-induced inflammation amplification, endothelium injury and cascade coagulation activation, and discuss the close correlation between elevated level of CHs and disease severity as well as mortality in patients with sepsis. Furthermore, current state-of-the-art on anti-histone therapy with antibodies, histone-binding proteins (namely recombinant thrombomodulin and activated protein C), and heparin is summarized to propose promising approaches for sepsis treatment.
Topics: Alarmins; Animals; Anti-Inflammatory Agents; Biomarkers; Blood Coagulation; Disease Models, Animal; Endothelium, Vascular; Extracellular Traps; Heparin; Histones; Humans; Molecular Targeted Therapy; Prognosis; Protein C; Recombinant Proteins; Sepsis; Severity of Illness Index; Signal Transduction; Thrombomodulin
PubMed: 33868288
DOI: 10.3389/fimmu.2021.650184 -
Nutrients Jul 2022Diabetic kidney disease (DKD) is an emerging pandemic, paralleling the worldwide increase in obesity and diabetes mellitus. DKD is now the most frequent cause of...
Diabetic kidney disease (DKD) is an emerging pandemic, paralleling the worldwide increase in obesity and diabetes mellitus. DKD is now the most frequent cause of end-stage renal disease and is associated with an excessive risk of cardiovascular morbidity and mortality. DKD is a consequence of systemic endothelial dysfunction. The endothelial-dependent cytoprotective coagulation protease activated protein C (aPC) ameliorates glomerular damage in DKD, in part by reducing mitochondrial ROS generation in glomerular cells. Whether aPC reduces mitochondrial ROS generation in the tubular compartment remains unknown. Here, we conducted expression profiling of kidneys in diabetic mice (wild-type and mice with increased plasma levels of aPC, APC mice). The top induced pathways were related to metabolism and in particular to oxidoreductase activity. In tubular cells, aPC maintained the expression of genes related to the electron transport chain, PGC1-α expression, and mitochondrial mass. These effects were associated with reduced mitochondrial ROS generation. Likewise, NLRP3 inflammasome activation and sterile inflammation, which are known to be linked to excess ROS generation in DKD, were reduced in diabetic APC mice. Thus, aPC reduces mitochondrial ROS generation in tubular cells and dampens the associated renal sterile inflammation. These studies support approaches harnessing the cytoprotective effects of aPC in DKD.
Topics: Animals; Diabetes Mellitus, Experimental; Diabetic Nephropathies; Inflammation; Kidney; Mice; Protein C; Reactive Oxygen Species
PubMed: 35956315
DOI: 10.3390/nu14153138 -
Journal of Thrombosis and Haemostasis :... Dec 2023Extracellular histone H3 is implicated in several pathologies including inflammation, cell death, and organ failure. Neutralization of histone H3 is a strategy that was...
BACKGROUND
Extracellular histone H3 is implicated in several pathologies including inflammation, cell death, and organ failure. Neutralization of histone H3 is a strategy that was shown beneficial in various diseases, such as rheumatoid arthritis, myocardial infarction, and sepsis. It was shown that activated protein C (APC) can cleave histone H3, which reduces histone cytotoxicity. However, due to the anticoagulant properties of APC, the use of APC is not optimal for the treatment of histone-mediated cytotoxicity, in view of its associated bleeding side effects.
OBJECTIVES
This study aimed to investigate the detailed molecular interactions between human APC and human histone H3, and subsequently use molecular docking and molecular dynamics simulation methods to identify key interacting residues that mediate the interaction between APC and histone H3 and to generate novel optimized APC variants.
METHODS
After molecular simulations, the designed APC variants 3D2D-APC (Lys37-39Asp and Lys62-63Asp) and 3D2D2A-APC (Lys37-39Asp, Lys62-63Asp, and Arg74-75Ala) were recombinantly expressed and their abilities to function as anticoagulant, to bind histones, and to cleave histones were tested and correlated with their cytoprotective properties.
RESULTS
Compared with wild type-APC, both the 3D2D-APC and 3D2D2A-APC variants showed a significantly decreased anticoagulant activity, increased binding to histone H3, and similar ability to proteolyze histone H3.
CONCLUSIONS
Our data show that it is possible to rationally design APC variants that may be further developed into therapeutic biologicals to treat histone-mediated disease, by proteolytic reduction of histone-associated cytotoxic properties that do not induce an increased bleeding risk.
Topics: Humans; Anticoagulants; Hemorrhage; Histones; Molecular Docking Simulation; Protein C; Proteolysis
PubMed: 37657561
DOI: 10.1016/j.jtha.2023.08.023 -
Blood Mar 2022Rebalancing the hemostatic system by targeting endogenous anticoagulant pathways, like the protein C (PC) system, is being tested as a means of improving hemostasis in...
Rebalancing the hemostatic system by targeting endogenous anticoagulant pathways, like the protein C (PC) system, is being tested as a means of improving hemostasis in patients with hemophilia. Recent intravital studies of hemostasis demonstrated that, in some vascular contexts, thrombin activity is sequestered in the extravascular compartment. These findings raise important questions about the context-dependent contribution of activated PC (APC) to the hemostatic response, because PC activation occurs on the surface of endothelial cells. We used a combination of pharmacologic, genetic, imaging, and computational approaches to examine the relationships among thrombin spatial distribution, PC activation, and APC anticoagulant function. We found that inhibition of APC activity, in mice either harboring the factor V Leiden mutation or infused with an APC-blocking antibody, significantly enhanced fibrin formation and platelet activation in a microvascular injury model, consistent with the role of APC as an anticoagulant. In contrast, inhibition of APC activity had no effect on hemostasis after penetrating injury of the mouse jugular vein. Computational studies showed that differences in blood velocity, injury size, and vessel geometry determine the localization of thrombin generation and, consequently, the extent of PC activation. Computational predictions were tested in vivo and showed that when thrombin generation occurred intravascularly, without penetration of the vessel wall, inhibition of APC significantly increased fibrin formation in the jugular vein. Together, these studies show the importance of thrombin spatial distribution in determining PC activation during hemostasis and thrombosis.
Topics: Animals; Anticoagulants; Endothelial Cells; Fibrin; Hemostasis; Hemostatics; Humans; Mice; Protein C; Thrombin; Thrombosis
PubMed: 34890454
DOI: 10.1182/blood.2021014338 -
Journal of the American Society of... Aug 2020Diabetic nephropathy (dNP), now the leading cause of ESKD, lacks efficient therapies. Coagulation protease-dependent signaling modulates dNP, in part the G...
BACKGROUND
Diabetic nephropathy (dNP), now the leading cause of ESKD, lacks efficient therapies. Coagulation protease-dependent signaling modulates dNP, in part the G protein-coupled, protease-activated receptors (PARs). Specifically, the cytoprotective protease-activated protein C (aPC) protects from dNP, but the mechanisms are not clear.
METHODS
A combination of approaches and mouse models evaluated the role of aPC-integrin interaction and related signaling in dNP.
RESULTS
The zymogen protein C and aPC bind to podocyte integrin-, a subunit of integrin-. Deficiency of this integrin impairs thrombin-mediated generation of aPC on podocytes. The interaction of aPC with integrin- induces transient binding of integrin- with G and controls PAR-dependent RhoA signaling in podocytes. Binding of aPC to integrin- its RGD sequence is required for the temporal restriction of RhoA signaling in podocytes. In podocytes lacking integrin-, aPC induces sustained RhoA activation, mimicking the effect of thrombin. , overexpression of wild-type aPC suppresses pathologic renal RhoA activation and protects against dNP. Disrupting the aPC-integrin- interaction by specifically deleting podocyte integrin- or by abolishing aPC's integrin-binding RGD sequence enhances RhoA signaling in mice with high aPC levels and abolishes aPC's nephroprotective effect. Pharmacologic inhibition of PAR1, the pivotal thrombin receptor, restricts RhoA activation and nephroprotects RGE-aPC and wild-type mice. aPC-integrin- acts as a rheostat, controlling PAR1-dependent RhoA activation in podocytes in diabetic nephropathy. These results identify integrin- as an essential coreceptor for aPC that is required for nephroprotective aPC-PAR signaling in dNP.
Topics: Animals; Cytoprotection; Diabetic Nephropathies; Endothelial Protein C Receptor; GTP-Binding Protein alpha Subunits, G12-G13; HEK293 Cells; Humans; Integrin beta3; Mice; Mice, Inbred C57BL; Podocytes; Protein C; Receptor, PAR-1; rhoA GTP-Binding Protein
PubMed: 32709711
DOI: 10.1681/ASN.2019111163 -
European Journal of Neurology Feb 2020The involvement of protein C (PC) pathway components in multiple sclerosis (MS) has scarcely been explored. The aim was to investigate their levels in relation to... (Observational Study)
Observational Study
BACKGROUND AND PURPOSE
The involvement of protein C (PC) pathway components in multiple sclerosis (MS) has scarcely been explored. The aim was to investigate their levels in relation to clinical and neurodegenerative magnetic resonance imaging (MRI) outcomes in patients.
METHODS
In all, 138 MS patients and 42 healthy individuals were studied. PC, protein S (PS) and soluble endothelial protein C receptor (sEPCR) were evaluated by multiplex assays and enzyme-linked immunosorbent assay. Regression analyses between 3 T MRI outcomes and PC pathway components were performed. ancova was used to compare MRI volumes based on protein level quartiles. Partial correlation was assessed amongst levels of PC pathway components and hemostasis protein levels, including soluble thrombomodulin (sTM), heparin cofactor II (HCII), plasminogen activator inhibitor 1 (PAI-1) and factor XII (FXII). The variation of PC concentration across four time points was evaluated in 32 additional MS patients.
RESULTS
There was an association between PC concentration, mainly reflecting the zymogen PC, and MRI measures for volumes of total gray matter (GM) (P = 0.003), thalamus (P = 0.007), cortex (P = 0.008), deep GM (P = 0.009) and whole brain (P = 0.026). Patients in the highest PC level quartile were characterized by the lowest GM volumes. Correlations of PC-HCII, PC-FXII and sEPCR-sTM values were detectable in MS patients, whilst PC-PS and PS-PAI-1 correlations were present in healthy individuals only.
CONCLUSIONS
Protein C plasma concentrations might be associated with neurodegenerative MRI outcomes in MS. Several differences in correlation amongst protein plasma levels suggest dysregulation of PC pathway components in MS patients. The stability of PC concentration over time supports a PC investigation in relation to GM atrophy in MS.
Topics: Adult; Brain; Cross-Sectional Studies; Disease Progression; Endothelial Protein C Receptor; Female; Gray Matter; Humans; Magnetic Resonance Imaging; Male; Middle Aged; Multiple Sclerosis; Protein C; Protein S; Signal Transduction; Treatment Outcome
PubMed: 31408242
DOI: 10.1111/ene.14058 -
Deutsches Arzteblatt International Sep 2022
Topics: Infant, Newborn; Humans; Protein C Deficiency; Infant, Premature; Surface-Active Agents
PubMed: 36519344
DOI: 10.3238/arztebl.m2022.0158