Inflammation, endothelium, and coagulation in sepsis

Chebulagic acid inhibits the LPS-induced expression of TNF-α and IL-1β in endothelial cells by suppressing MAPK activation

Inflammatory response in the vasculature, including the overexpression of tumor necrosis factor (TNF)-α and interleukin (IL)-1β, has been demonstrated to increase the risk of thrombosis development. Chebulagic acid (CA) is a key chemical component in the traditional Mongolian anti-thrombotic drug Garidi-13, and has been suggested to exert anti-inflammatory and anti-infective effects. The present study aimed to evaluate the regulatory impact of CA on a number of biological processes, including lipopolysaccharide (LPS)-induced inflammation, LPS-promoted mitogen-activated protein kinase (MAPK) activation and the expression of toll-like receptor (TLR)4 in EA.hy926 human endothelial cells. The results indicated that CA significantly inhibited the LPS-induced upregulation of TNF-α and IL-1β in a dose- and time-dependent manner. Furthermore, LPS-activated MAPK signaling was inhibited by CA treatment in the EA.hy926 cells. However, TLR4, which serves a key function in LPS-induced inflammation as the receptor of LPS, was not regulated by the CA treatment. In summary, the results of the present study indicate that CA inhibits the LPS-induced promotion of TNF-α and IL-1β in endothelial cells by suppressing MAPK activation, which may contribute to the anti-thrombotic effect of Garidi-13.

Association of the Plasma Platelet-Derived Microparticles to Platelet Count Ratio with Hospital Mortality and Disseminated Intravascular Coagulopathy in Critically Ill Patients

AIM

The role of platelet-derived microparticles (PDMPs) in the crosstalk between coagulopathy and inflammation in critically ill patients remains unclear. The aim of this cohort observational study was to investigate the associations between the PDMP levels and hospital mortality or disseminated intravascular coagulopathy (DIC).

METHODS

This study included 119 patients who were admitted to the ICU. The PDMP levels were measured using an enzyme-linked immunosorbent assay three times a week, for a total of 372 samples. We calculated the maximum (max) PDMP value, max PDMP/platelet (PDMP/Plts) ratio (converted to the PDMP levels per 10(4) platelets) and nadir platelet count during the ICU stay. Baseline patient data and scores, including the Japanese Association for Acute Medicine (JAAM) DIC score, were collected, and potential predictors were analyzed for possible associations with hospital mortality.

RESULTS

The max PDMP/Plts ratio was significantly different comparing the survivors (n=98: median, 2.54) and non-survivors (n=21: median 17.59; p＜0.001). There was a weak but statistically significant negative correlation between the max PDMP level and nadir platelet count (r=-0.332, p＜0.001). The max PDMP level and max PDMP/Plts ratio were higher in the DIC group (81.48 and 9.27, respectively) than in the non-DIC group (34.88 and 2.35, p=0.001 and p＜0.001, respectively). The max PDMP/Plts ratio was the only variable found to be independently associated with hospital mortality according to a multivariate logistic regression analysis.

CONCLUSIONS

PDMPs are involved in the development of DIC but are not related to hospital mortality. There is a good association between the PDMP/Plts ratio and hospital mortality and/or DIC in critically ill patients.

Platelet interaction with bacterial toxins and secreted products

Bacteria that enter the bloodstream will encounter components of the cellular and soluble immune response. Platelets contribute to this response and have emerged as an important target for bacterial pathogens. Bacteria produce diverse extracellular proteins and toxins that have been reported to modulate platelet function. These interactions can result in complete or incomplete platelet activation or inhibition of platelet activation, depending on the bacteria and bacterial product. The nature of the platelet response may be highly relevant to disease pathogenesis.

Antiplatelet and antithrombotic activities of purpurogallin in vitro and in vivo

Enzymatic oxidation of pyrogallol was efficiently transformed to an oxidative product, purpurogallin (PPG). Here, the anticoagulant activities of PPG were examined by monitoring activated partial thromboplastin time (aPTT), prothrombin time (PT), and the activities of thrombin and activated factor X (FXa). And, the effects of PPG on expression of plasminogen activator inhibitor type 1 (PAI-1) and tissue-type plasminogen activator (t-PA) were evaluated in tumor necrosis factor (TNF)-α activated human umbilical vein endothelial cells (HUVECs). Treatment with PPG resulted in prolonged aPTT and PT and inhibition of the activities of thrombin and FXa, as well as inhibited production of thrombin and FXa in HUVECs. In addition, PPG inhibited thrombin-catalyzed fibrin polymerization and platelet aggregation. PPG also elicited anticoagulant effects in mice. In addition, treatment with PPG resulted in significant reduction of the PAI-1 to t-PA ratio. Collectively, PPG possesses antithrombotic activities and offers a basis for development of a novel anticoagulant. [BMB Reports 2014; 47(7): 376-381]

Endothelial barrier dysfunction in septic shock

The endothelium provides an essential and selective membrane barrier that regulates the movement of water, solutes, gases, macromolecules and the cellular elements of the blood from the tissue compartment in health and disease. Its structure and continuous function is essential for life for all vertebrate organisms. Recent evidence indicates that the endothelial surface does not have a passive role in systemic inflammatory states such as septic shock. In fact, endothelial cells are in dynamic equilibrium with a myriad of inflammatory mediators and elements of the innate immune and coagulation systems to orchestrate the host response in sepsis. The barrier function of the endothelial surface is almost uniformly impaired in septic shock, and it is likely that this contributes to adverse outcomes. In this review, we will highlight recent advances in the understanding of the signalling events that regulate endothelial function and molecular events that induce endothelial dysfunction in sepsis. Endothelial barrier repair strategies as a treatment for sepsis include modulation of C5a, high-mobility group box 1 and VEGF receptor 2; stimulation of angiopoietin-1, sphingosine 1 phosphate receptor 1 and Slit; and a number of other innovative approaches.

Plasmatic isoforms of cytokeratin 18 and RAGE after severe trauma: a longitudinal cohort study

BACKGROUND

Life-threatening traumatic injuries lead to a complex inflammation-driven pathophysiology. Receptor of advanced glycation end product (RAGE) is a multiligand receptor of several endogenous alarmins, while cytokeratin 18 is a structural component of the filament of epithelial cells. Both proteins can be frequently found in plasma of patients with different diseases, whereby they have distinct underlying mechanism of formation. In this prospective observational study, we wanted to shed light on the kinetic of plasmatic RAGE and cytokeratin 18 isoforms after severe trauma, thereby also addressing the association of these markers with inflammation and their potential use as biomarkers.

METHODS

Plasma samples of 77 patients with severe multiple trauma as defined by an Injury Severity Score (ISS) 16 or greater were obtained from a local repository and levels of soluble RAGE, endogenous secretory RAGE, cytokeratin 18, cleaved cytokeratin 18, and interleukin 6 by enzyme-linked immunosorbent assay. Demographic and routine parameters of the cohort were extracted from an electronic patient data management system.

RESULTS

Both RAGE isoforms were transiently increased in plasma within 24 hours after trauma, while cytokeratin 18 levels were unchanged. Moreover, soluble RAGE concentrations in patients with thoracic injuries were higher compared with patients without injury, and both isoforms of RAGE discriminated between patients with most severe adult respiratory distress syndrome and patients with milder forms. In addition, cleaved and total cytokeratin 18 levels differ between patients with hepatic dysfunction and normal function, without possessing discriminatory power. RAGE and cytokeratin 18 isoforms correlated significantly but to a low extent with interleukin 6, while the isoforms of both parameters correlated to a high extent with one another.

CONCLUSION

The release of RAGE (but not cytokeratin 18) isoforms occurs early and transiently after trauma and is associated with the extent of injury and inflammatory response. RAGE and cytokeratin 18 isoforms have the potential to act as diagnostic or prognostic biomarkers of lung and hepatic dysfunction.

LEVEL OF EVIDENCE

Epidemiologic/prognostic study, level IV.

Beta-blocker use in severe sepsis and septic shock: a systematic review

OBJECTIVE

Recent growing evidence suggests that beta-blocker treatment could improve cardiovascular dynamics and possibly the outcome of patients admitted to intensive care with severe sepsis or septic shock.

DESIGN

Systematic review.

DATA SOURCES

MEDLINE and EMBASE healthcare databases.

REVIEW METHODS

To investigate this topic, we conducted a systematic review of the above databases up to 31 May 2015. Due to the clinical novelty of the subject, we also included non-randomized clinical studies. We focused on the impact of beta-blocker treatment on mortality, also investigating its effects on cardiovascular, immune and metabolic function. Evidence from experimental studies was reviewed as well.

RESULTS

From the initial search we selected 10 relevant clinical studies. Five prospective studies (two randomized) assessed the hemodynamic effects of the beta1-blocker esmolol. Heart rate decreased significantly in all, but the impact on other parameters differed. The imbalance between prospective studies' size (10 to 144 patients) and the differences in their design disfavor a meta-analysis. One retrospective study showed improved hemodynamics combining metoprolol and milrinone in septic patients, and another retrospective study found no association between beta-blocker administration and mortality. We also found three case series. Twenty-one experimental studies evaluated the hemodynamic, immune and/or metabolic effects of selective and/or non-selective beta-blockers in animal models of sepsis (dogs, mice, pigs, rats, sheep), yielding conflicting results.

CONCLUSIONS

Whilst there is not enough prospective data to conduct a meta-analysis, the available clinical data are promising. We discuss the ability of beta blockade to modulate sepsis-induced alterations at cardiovascular, metabolic, immunologic and coagulation levels.

Simvastatin inhibits apoptosis of endothelial cells induced by sepsis through upregulating the expression of Bcl-2 and downregulating Bax

BACKGROUND

Many studies have showed that apoptosis of endothelial cells plays a curial role in the progress of sepsis. But the role of simvastatin in apoptosis of endothelial cells induced by sepsis is not clear. The present study aimed to investigate the role of simvastatin in apoptosis of endothelial cells induced by sepsis and its mechanism.

METHODS

Human umbilical vein endothelial cells (HUVECs) were randomly divided into three groups: control group, sepsis serum intervention group (sepsis group) and simvastatin+sepsis serum intervention group (simvastatin group). After 24-hour incubation with corresponding culture medium, the relative growth rate of HUVECS in different groups was detected by MTT assay; the apoptosis of HUVECs was detected by Hoechst33258 assay and flow cytometry; and the expression of the Bcl-2 and Bax genes of HUVECs was detected by PCR.

RESULTS

Compared with the sepsis group, HUVECs in the simvastatin group had a higher relative growth rate. Apoptotic HUVECs decreased significantly in the simvastatin group in comparison with the sepsis group. Expression of the Bcl-2 gene in HUVECs decreased obviously, but the expression of the Bax gene increased obviously after 24-hour incubation with sepsis serum; however, the expression of the Bcl-2 and Bax genes was just the opposite in the simvastatin group.

CONCLUSIONS

Our study suggests that simvastatin can inhibit apoptosis of endothelial cells induced by sepsis through upregulating the expression of Bcl-2 and downregulating Bax. It may be one of the mechanisms for simvastatin to treat sepsis.

Neonatal sepsis and inflammatory mediators

Neonatal sepsis is a major cause of morbidity and mortality and its signs and symptoms are nonspecific, which makes the diagnosis difficult. The routinely used laboratory tests are not effective methods of analysis, as they are extremely nonspecific and often cause inappropriate use of antibiotics. Sepsis is the result of an infection associated with a systemic inflammatory response with production and release of a wide range of inflammatory mediators. Cytokines are potent inflammatory mediators and their serum levels are increased during infections, so changes from other inflammatory effector molecules may occur. Although proinflammatory and anti-inflammatory cytokines have been identified as probable markers of neonatal infection, in order to characterize the inflammatory response during sepsis, it is necessary to analyze a panel of cytokines and not only the measurement of individual cytokines. Measurements of inflammatory mediators bring new options for diagnosing and following up neonatal sepsis, thus enabling early treatment and, as a result, increased neonatal survival. By taking into account the magnitude of neonatal sepsis, the aim of this review is to address the role of cytokines in the pathogenesis of neonatal sepsis and its value as a diagnostic criterion.

Differential and opposing effects of imatinib on LPS- and ventilator-induced lung injury

Endothelial dysfunction underlies the pathophysiology of vascular disorders such as acute lung injury (ALI) syndromes. Recent work has identified the Abl family kinases (c-Abl and Arg) as important regulators of endothelial cell (EC) barrier function and suggests that their inhibition by currently available pharmaceutical agents such as imatinib may be EC protective. Here we describe novel and differential effects of imatinib in regulating lung pathophysiology in two clinically relevant experimental models of ALI. Imatinib attenuates endotoxin (LPS)-induced vascular leak and lung inflammation in mice but exacerbates these features in a mouse model of ventilator-induced lung injury (VILI). We next explored these discrepant observations in vitro through investigation of the roles for Abl kinases in cultured lung EC. Imatinib attenuates LPS-induced lung EC permeability, restores VE-cadherin junctions, and reduces inflammation by suppressing VCAM-1 expression and inflammatory cytokine (IL-8 and IL-6) secretion. Conversely, in EC exposed to pathological 18% cyclic stretch (CS) (in vitro model of VILI), imatinib decreases VE-cadherin expression, disrupts cell-cell junctions, and increases IL-8 levels. Downregulation of c-Abl expression with siRNA attenuates LPS-induced VCAM-1 expression, whereas specific reduction of Arg reduces VE-cadherin expression in 18% CS-challenged ECs to mimic the imatinib effects. In summary, imatinib exhibits pulmonary barrier-protective and anti-inflammatory effects in LPS-injured mice and lung EC; however, imatinib exacerbates VILI as well as dysfunction in 18% CS-EC. These findings identify the Abl family kinases as important modulators of EC function and potential therapeutic targets in lung injury syndromes.

Potential deleterious role of anti-Neu5Gc antibodies in xenotransplantation

Human beings do not synthesize the glycolyl form of the sialic acid (Neu5Gc) and only express the acetylated form of the sugar, whereas a diet-based intake of Neu5Gc provokes a natural immunization and production of anti-Neu5Gc antibodies in human serum. However, Neu5Gc is expressed on mammal glycoproteins and glycolipids in most organs and cells. We review here the relevance of Neu5Gc and anti-Neu5Gc antibodies in the context of xenotransplantation and the use of animal-derived molecules and products, as well as the possible consequences of a long-term exposure to anti-Neu5Gc antibodies in recipients of xenografts. In addition, the importance of an accurate estimation of the anti-Neu5Gc response following xenotransplantation and the future contribution of knockout animals mimicking the human situation are also assessed.

Effects of clopidogrel on horses with experimentally induced endotoxemia

OBJECTIVE

To evaluate the effects of clopidogrel on clinical and clinicopathologic variables in healthy horses with experimentally induced endotoxemia.

ANIMALS

12 adult mares. Procedures-Horses were assigned with a randomization procedure to receive clopidogrel (4 mg/kg, once, then 2 mg/kg, q 24 h; n = 6) or a placebo (6) through a nasogastric tube. After 72 hours of treatment, horses received lipopolysaccharide (LPS; 30 ng/kg, IV). Heart rate, respiratory rate, rectal temperature, CBC variables, plasma fibrinogen concentration, serum tumor necrosis factor-α concentration, plasma von Willebrand factor concentration, and measures of platelet activation (including ADP- and collagen-induced platelet aggregation and closure times, thrombelastography variables, and results of flow cytometric detection of platelet membrane P-selectin, phosphatidylserine, and microparticles) were determined at various times before and after LPS administration by investigators unaware of the treatment groups. Statistical analyses were performed with repeated-measures ANOVA.

RESULTS

4 of 6 clopidogrel-treated horses had significant decreases in ADP-induced platelet aggregation before and after LPS administration. Heart rate increased significantly after LPS administration only for the placebo group. No significant differences were detected between groups for CBC variables, closure time, and plasma concentration of fibrinogen or serum concentration of tumor necrosis factor-α, and no clinically relevant differences were detected for other hemostatic variables.

CONCLUSIONS AND CLINICAL RELEVANCE

In this study, administration of LPS did not induce platelet hyperreactivity in horses on the basis of measures of platelet adhesion, aggregation, degranulation, and procoagulant activity. Administration of clopidogrel was associated with variable platelet antiaggregatory activity and attenuated some clinical signs of endotoxemia.

Thrombocytopenia impairs host defense in gram-negative pneumonia-derived sepsis in mice

Thrombocytopenia is a common finding in sepsis and associated with a worse outcome. We used a mouse model of pneumonia-derived sepsis caused by the human pathogen Klebsiella pneumoniae to study the role of platelets in host response to sepsis. Platelet counts (PCs) were reduced to less than a median of 5 × 10(9)/L or to 5 to 13 × 10(9)/L by administration of a depleting antibody in mice infected with Klebsiella via the airways. Thrombocytopenia was associated with strongly impaired survival during pneumonia-derived sepsis proportional to the extent of platelet depletion. Thrombocytopenic mice demonstrated PC-dependent enhanced bacterial growth in lungs, blood, and distant organs. Severe thrombocytopenia resulted in hemorrhage at the primary site of infection, but not in distant organs. PCs of 5 to 13 × 10(9)/L were sufficient to largely maintain hemostasis in infected lungs. Thrombocytopenia did not influence lung inflammation or neutrophil recruitment and did not attenuate local or systemic activation of coagulation or the vascular endothelium. PCs <5 × 10(9)/L even resulted in enhanced coagulation and endothelial cell activation, which coincided with increased proinflammatory cytokine levels. In accordance, low PCs in whole blood enhanced Klebsiella-induced cytokine release in vitro. These data suggest that platelets play an important role in host defense to Klebsiella pneumosepsis.

Hematopoietic but not endothelial cell MyD88 contributes to host defense during gram-negative pneumonia derived sepsis

Klebsiella pneumoniae is an important cause of sepsis. The common Toll-like receptor adapter myeloid differentiation primary response gene (MyD)88 is crucial for host defense against Klebsiella. Here we investigated the role of MyD88 in myeloid and endothelial cells during Klebsiella pneumosepsis. Mice deficient for MyD88 in myeloid (LysM-Myd88(-/-)) and myeloid plus endothelial (Tie2-Myd88(-/-)) cells showed enhanced lethality and bacterial growth. Tie2-Myd88(-/-) mice reconstituted with control bone marrow, representing mice with a selective MyD88 deficiency in endothelial cells, showed an unremarkable antibacterial defense. Myeloid or endothelial cell MyD88 deficiency did not impact on lung pathology or distant organ injury during late stage sepsis, while LysM-Myd88(-/-) mice demonstrated a strongly attenuated inflammatory response in the airways early after infection. These data suggest that myeloid but not endothelial MyD88 is important for host defense during gram-negative pneumonia derived sepsis.

The role of hemostasis in infective endocarditis

Infective endocarditis (IE) is a thromboinflammatory disease of the endocardium, with pathophysiology mostly the result of the interplay between microorganisms and modifiers of the hemostasis system. In this setting, the evidence gathered so far warrants a more systematic appraisal. In this review article, experimental and clinical data on the role of hemostasis in IE are summarized. Starting from the current pathogenetic model of IE, we discuss the dual role of platelets in this condition, the microbial interaction with the hemostasis system, also describing nonspecific hemostasis changes during sepsis. We finally propose our hypothesis of thrombophilia as a possible trigger of IE, highlighting the challenges that the study of hemostasis in IE presents. The role of hemostasis in IE appears to be an exciting field of research. The activity of the hemostasis system is highly relevant in terms of susceptibility, progression, and treatment of IE. Pharmacologic modulation of hemostasis before and after IE onset is possible and represents still a largely unexplored area of study.

The role of proteomics in understanding biological mechanisms of sepsis

Sepsis is a systemic inflammatory state caused by infection. Complications of this infection with multiple organ failure lead to more lethal conditions, such as severe sepsis and septic shock. Sepsis is one of the leading causes of US deaths. Novel biomarkers with high sensitivity and specificity may be helpful for early diagnosis of sepsis and for improvement of patient outcomes through the development of new therapies. Mass spectrometry-based proteomics offers powerful tools to identify such biomarkers and furthermore to give insight to fundamental mechanisms of this clinical condition. In this review, we summarize findings from proteomics studies of sepsis and how their applications have provided more understanding into the pathogenesis of septic infection. Literatures related to "proteomics", "sepsis", "systemic inflammatory response syndrome", "severe sepsis", "septic infection", and "multiple organ dysfunction syndrome" were searched using PubMed. Findings about neonatal and adult sepsis are discussed separately. Within the adult sepsis studies, results are grouped based on the models (e.g., human or animal). Across investigations in clinical populations and in rodent and mammalian animal models, biological pathways, such as inflammatory and acute phase response, coagulation, complement, mitochondrial energy metabolism, chaperones, and oxidative stress, are altered at the protein level. These proteomics studies have discovered many novel biomarker candidates of septic infection. Validation the clinical use of these biomarker candidates may significantly impact the diagnosis and prognosis of sepsis. In addition, the molecular mechanisms revealed by these studies may also guide the development of more effective treatments.

Elevated biomarkers of endothelial dysfunction/activation at ICU admission are associated with sepsis development

Widespread endothelial activation and dysfunction often precede clinical sepsis. Several endothelium-related molecules have been investigated as potential biomarkers for early diagnosis and/or prognosis of sepsis, providing different results depending on study designs. Such factors include endothelial adhesion molecules like E- and P-selectin, and the intercellular adhesion molecule-1, vascular endothelial cadherin, growth factors such as Angiopoietin-1 and -2 and vascular endothelial growth factor, as well as von Willebrand factor antigen. We sought to investigate whether circulating biomarkers of endothelial activation/dysfunction measured at ICU admission are associated with subsequent sepsis development. Eighty-nine critically-ill patients admitted to a general ICU who met no sepsis criteria were studied. Plasma or serum levels of the above-mentioned endothelium-derived molecules were measured during the first 24h post ICU; acute physiology and chronic health evaluation (APACHE) II and sequential organ failure assessment (SOFA) scores, age, sex, diagnostic category, and circulating procalcitonin (PCT) and C-reactive protein (CRP) levels were additionally measured or recorded. Forty-five patients subsequently became septic and 44 did not. Soluble (s) E- and P-selectin levels, circulating PCT, SOFA score and diagnostic category were significantly different between the two groups. Multiple logistic regression analysis associated elevated sE- and sP-selectin levels and SOFA with an increased risk of developing sepsis, while multiple Cox regression analysis identified sE- and sP-selectin levels as the only parameters related to sepsis appearance with time [RR=1.026, 95%CI=1.008-1.045, p=0.005; RR=1.005 (by 10 units), 95%CI=1.000-1.010, p=0.034, respectively]. When trauma patients were independently analyzed, multiple Cox regression analysis revealed sE-selectin to be the only molecule associated with sepsis development with time (RR=1.041, 95%CI: 1.019-1.065; p<0.001). In conclusion, in our cohort of initially non-septic critically-ill patients, high levels of the circulating endothelial adhesion molecules E- and P-selectin, measured at ICU admission, appear to be associated with sepsis development in time.

Is the neutrophil a 'prima donna' in the procoagulant process during sepsis?

Activation of the coagulation system is a fundamental host defense mechanism. Microorganisms that have invaded the body are trapped and disposed of in clots. Monocytes/macrophages are widely accepted as the main players in the procoagulant process; however, recent evidence suggests that neutrophils also play important roles. Tissue factor, which initiates the extrinsic coagulation cascade, is reportedly expressed on the surface of neutrophils, as well as on microparticles derived from neutrophils. Neutrophil extracellular traps (NETs) are another source of tissue factor. The components of NETs, such as DNA, histones, and granule proteins, also provide procoagulant activities. For instance, DNA initiates the intrinsic pathway, histones are a strong generator of thrombin, and granule proteins such as neutrophil elastase, cathepsin G and myeloperoxidase contribute to the suppression of the anticoagulation systems. Although understanding of the mechanisms that are involved in coagulation/fibrinolysis in sepsis has gradually progressed, the impact of neutrophils on thrombogenicity during sepsis remains to be addressed. Since the importance of the connection between coagulation and inflammation is advocated nowadays, further research on neutrophils is required.

Unfractionated heparin suppresses lipopolysaccharide-induced monocyte chemoattractant protein-1 expression in human microvascular endothelial cells by blocking Krüppel-like factor 5 and nuclear factor-κB pathway

Unfractionated heparin (UFH) and low-molecular-weight heparins (LMWH), apart from anticoagulant activities, contain a variety of biological properties such as anti-inflammatory actions possibly affecting sepsis. Chemokines are vital for promoting the movement of circulating leukocytes to the site of infection and are involved in the pathogenesis of sepsis. The purpose of this study was to investigate the effects and potential mechanisms of UFH on lipopolysaccharide (LPS)-induced chemokine production in human pulmonary microvascular endothelial cells (HPMECs). HPMECs were pretreated with UFH (0.1 U/ml and 1 U/ml), 15 min prior to stimulation with LPS (10 μg/ml). Cells were cultured under various experimental conditions for 2 h and 6 h for analysis. UFH markedly decreased LPS-induced interleukin (IL)-8 and monocyte chemoattractant protein-1 (MCP-1) mRNA and protein expression in HPMECs. UFH also attenuated the secretion of these chemokines in culture supernatants. In addition, UFH blocked the chemotactic activities of LPS-stimulated HPMECs supernatants on monocytes migration as expected. UFH inhibited LPS-induced Krüppel-like factor 5 (KLF-5) mRNA and protein levels. Concurrently, UFH reduced nuclear factor (NF)-κB nuclear translocation. Importantly, transfection with siRNA targeting KLF-5 reduced NF-κB activation and chemokines expression. These results demonstrate that interfering with KLF-5 mediated NF-κB activation might contribute to the inhibitory effects of chemokines and monocytes migration by UFH in LPS-stimulated HPMECs.

The role of platelets in sepsis

Platelets are small circulating anucleate cells that are of crucial importance in haemostasis. Over the last decade, it has become increasingly clear that platelets play an important role in inflammation and can influence both innate and adaptive immunity. Sepsis is a potentially lethal condition caused by detrimental host response to an invading pathogen. Dysbalanced immune response and activation of the coagulation system during sepsis are fundamental events leading to sepsis complications and organ failure. Platelets, being major effector cells in both haemostasis and inflammation, are involved in sepsis pathogenesis and contribute to sepsis complications. Platelets catalyse the development of hyperinflammation, disseminated intravascular coagulation and microthrombosis, and subsequently contribute to multiple organ failure. Inappropriate accumulation and activity of platelets are key events in the development of sepsis-related complications such as acute lung injury and acute kidney injury. Platelet activation readouts could serve as biomarkers for early sepsis recognition; inhibition of platelets in septic patients seems like an important target for immune-modulating therapy and appears promising based on animal models and retrospective human studies.

Leukocyte deformability is a novel biomarker to reflect sepsis-induced disseminated intravascular coagulation

Aim

Sepsis-induced disseminated intravascular coagulopathy is associated with a high mortality rate. The function and deformability of polymorphonuclear leukocytes change in patients with sepsis. The goal of this study was to characterize the changes in polymorphonuclear leukocyte deformability in patients with sepsis-induced disseminated intravascular coagulopathy and to evaluate the relationship between the severity of disseminated intravascular coagulopathy and the deformability of polymorphonuclear leukocytes.

Methods

Thirty-five patients with sepsis-induced disseminated intravascular coagulopathy at our department were enrolled in this study. These patients were diagnosed with severe sepsis and an acute disseminated intravascular coagulopathy score ≥ 4. Blood samples were obtained from these patients on days 1, 3, and 7. Polymorphonuclear leukocyte deformability was measured with a microchannel flow analyzer, and polymorphonuclear leukocyte activity, represented as CD11b, was measured by flow cytometry. In contrast, 14 patients who fulfilled with sepsis criteria but without complicated disseminated intravascular coagulopathy were also entered in this study.

Results

In patients with sepsis-induced disseminated intravascular coagulopathy, there was a significant correlation between their Japanese Association for Acute Medicine disseminated intravascular coagulopathy score and polymorphonuclear leukocyte deformability, and CD11b expression. Polymorphonuclear leukocytes became more stiffened and CD11b expression was higher in patients with sepsis-induced disseminated intravascular coagulopathy compared to patients without the condition.

Conclusion

Polymorphonuclear leukocyte deformability correlated with the severity of sepsis-induced disseminated intravascular coagulopathy and the response to treatment.

The coagulation system in melioidosis: from pathogenesis to new treatment strategies

Melioidosis, caused by the Gram-negative bacterium Burkholderia pseudomallei, is a dreadful disease common in South-East Asia and Northern Australia and is characterized by chronic suppurative lesions and pneumonia. Melioidosis may evolve into severe sepsis with multi-organ failure with high mortalities, despite proper antibiotic therapy. Besides activation of a strong pro-inflammatory host response, the coagulation system plays an important role during melioidosis, which is thought to be host-protective. In particular, a procoagulant state together with downregulation of anticoagulant pathways and activation of fibrinolysis are present, all closely interrelated with parameters of inflammation. This review presents an overview of recent studies in which the role of coagulation, anti-coagulation and fibrinolysis during melioidosis was investigated both in patients and in experimental settings.

[Deep venous thrombosis complications during infections in pediatric patients: analysis of a series of 24 cases]

Venous thromboembolism disease (VTE) is rare in children (5.3 of 10,000 hospitalized children). However, morbidity and mortality are high, especially when the child is already suffering from severe sepsis. We report an analytical study of 24 cases of deep venous thrombosis occurring in children during infection, recorded at the Montpellier University Hospital between 1999 and 2009. Many parameters were studied in each population (age, sex, familial and personal history of thrombosis, history of thrombophilia, the presence of a venous catheter, a causative organism, time to onset of thrombus, topography of lesions, acquired abnormalities of hemostasis, and thrombosis prophylaxis). The children were aged from 1 day of life to 16 years. Thromboses occurred in two clinical contexts: "contact" thrombosis (which appeared near the infection) and disseminated thrombosis. This is an early complication because in most of the cases, it appeared in the first 10 days of sepsis. Infection and coagulation appear to be closely related and the states of latent or decompensated disseminated intravascular coagulation are common. Nevertheless, it is not possible to predict the occurence of a thrombotic event. The presence of risk factors (venous catheters, acquired thrombophilia, or constitutional thrombophilia) may increase the thrombogenic potential of the infection. VTE should always be suspected and sought in case of an unfavorable clinical course, and routine prophylaxis of thrombosis during sepsis should be discussed.

Functional role of protease activated receptors in vascular biology

Protease activated receptors (PARs) are a small family of G protein-coupled receptors (GPCR) mediating the cellular effects of some proteases of the coagulation system, such as thrombin, or other proteases, such as trypsin or metalloproteinase 1. As the prototype of PARs, PAR1 is a seven transmembrane GPCR that, upon cleavage by thrombin, unmasks a new amino-terminus able to bind intramolecularly to PAR1 itself thus inducing signaling. In the vascular system, thrombin and other proteases of the coagulation-fibrinolysis system, such as plasmin, factor VIIa and factor Xa, activated protein C, are considered physiologically relevant agonists, and PARs appear to largely account for the cellular effects of these enzymes. In the vasculature, PARs are expressed on platelets, endothelial cells (ECs) and vascular smooth muscle cells (VSMCs). In the vessel wall, under physiological conditions, PARs are mainly expressed in ECs and participate in the regulation of vascular tone, by inducing endothelium-dependent relaxation. PAR activation on ECs promotes conversion of these cells into a proinflammatory phenotype, causes increase of vascular permeability, and the exposure/secretion of proteins and cytokines mediating the local accumulation of platelets and leukocytes. These effects contribute to the vascular consequences of sepsis and of diseases such as acute lung injury and acute respiratory distress syndrome. In normal arteries PARs are to a much lesser amount expressed on VSMCs. However, in conditions associated with endothelial dysfunction, PARs mediate contraction, proliferation, migration, hypertrophy of VSMCs and their production of extracellular matrix, thereby contributing to the pathophysiology of atherosclerosis and hypertension. Inhibition of protease-PAR interaction might thus become a potential therapeutic target in various vascular diseases.

Pulmonary arterial hypertension and sepsis: prothrombotic profile and inflammation can changes pulmonary mechanics?

Pulmonary arterial hypertension (PAH) is associated to cellular and structural alterations of lung vasculature. Endothelial dysfunction promotes vasoconstriction, smooth muscle hypertrophy, intimal proliferation, angioproliferative plexiform lesions, and in situ thrombosis increasing pulmonary vascular resistance and arterial stiffness. Indeed, an inflammatory component has been defined in PAH on the last years. Sepsis is a systemic complex syndrome, of infectious origin. The presence of inflammation is well established in this condition and it is also considered a risk factor for acute lung injury. Thrombotic events play important role in sepsis pathophysiology. The association between PAH and sepsis potentiate the metabolic oxygen consumption/offer imbalance, with very high mortality risk. Furthermore, it is possible that the association of these two conditions should intensify thrombotic events on pulmonary microcirculation, reducing area of pulmonary vascular bed available for blood flow. For the other side, an inflammation synergism observed on these two conditions should increase the respiratory system impedance.

Outer membrane vesicles alter inflammation and coagulation mediators

INTRODUCTION

Outer membrane vesicles (OMVs) were previously shown to be capable of initiating the inflammatory response seen in the transition of an infection to sepsis. However, another tenet of sepsis is the development of a hypercoagulable state and the role of OMVs in the development of this hypercoagulability has not been evaluated. The objective of this study was to evaluate the ability of OMVs to elicit endothelial mediators of coagulation and inflammation and induce platelet activation.

METHODS

Human umbilical vein endothelial cells (HUVECs) were incubated with OMVs and were analyzed for the expression of tissue factor (TF), thrombomodulin, and the adhesion molecules P-selectin and E-selectin. Supernatants of OMV-treated HUVECs were mixed with whole blood and assessed for prothrombotic monocyte-platelet aggregates (MPA).

RESULTS

OMVs induce significantly increased expression of TF, E-selectin, and P-selectin, whereas, the expression of thrombomodulin by HUVECs is significantly decreased (P < 0.05). The lipopolysaccharide inhibitor clearly inhibited the expression of E-selectin following incubation with OMVs, although its impact on TF and thrombomodulin expression was nominal. Incubation of whole blood with supernatant from HUVECs exposed to OVMs resulted in increased MPAs.

CONCLUSIONS

This study demonstrates that, at the cellular level, OMVs from pathogenic bacteria play a complex role in endothelial activation. Although OMV-bound lipopolysaccharide modulates inflammatory proteins, including E-selectin, it has a negligible effect on the tested coagulation mediators. Additionally, endothelial activation by OMVs facilitates platelet activation as indicated by increased MPAs. By influencing the inflammatory and coagulation cascades, OMVs may contribute to the hypercoagulable response seen in sepsis.

Endocan is useful biomarker of survival and severity in sepsis

INTRODUCTION

Coagulation abnormalities which occur as a consequence of endothelial changes are recognized as diagnostic criteria for sepsis, but significance of these changes in the outcome prognosis and prediction of the course of sepsis is still not accurately defined.

MATERIALS AND METHODS

60 patients who fulfilled the criteria for diagnosis of sepsis were included in our study. Patients were categorized in two groups according to sepsis severity and organ failure and MODS development was assessed in the first 48 h from ICU admission. Prothrombin time (PT), activated partial thromboplastin time (aPTT) and endothelial cell specific molecule-1(endocan) levels, as well as procalcitonin (PCT) and C-reactive protein (CRP) were determined within the first 24h of the onset of the disease. Predictive APACHE II (Acute Physiology and Chronic Health Evaluation II) and SOFA (Sequential Organ Failure Assessment) scores were calculated on the day of ICU admission. Data were used to determine an association between day 1 biomarker levels, organ dysfunction score values and the development of organ failure, multiple organ dysfunction syndrome (MODS), and mortality during 28 days. These connections were determined by plotting of receiver operating characteristic (ROC) curves. Differences between groups were assessed by Mann-Whitney U test. Categorical variables were compared using chi-square test.

RESULTS

Concentration of endocan was significantly higher in the group of patients with sepsis induced organ failure, MODS development and in the group of non- survivors in contrast to group with less severe form of the disease, without multiorgan failure, and in contrast to group of survivors (p<0.05). Values of areas under the ROC curves showed that endocan levels had good discriminative power for more severe course of sepsis, MODS development and possible discriminative power for mortality prediction (AUC: 0.81, 0.67, 0.71 retrospectively), better than PCT for fatality (AUC:053) and better than APACHE II (AUC:0.55) and SOFA (AUC: 0.57) scores for organ failure.

CONCLUSIONS

Results of our study show that endocan can be used as strong and significant predictor of sepsis severity and outcome, perhaps even better than SOFA and APACHE II scores.

Plasma somatostatin-like immunoreactivity increases in the plasma of septic patients and rats with systemic inflammatory reaction: experimental evidence for its sensory origin and protective role

Alterations of somatostatin-like immunoreactivity (SST-LI) in the plasma of 11 systemic inflammatory response syndrome (SIRS) patients were investigated in correlation with cytokines, adhesion molecules and coagulation markers repeatedly during 4 days. The origin and role of SST were studied in the cecum ligation and puncture (CLP) rat SIRS model. Capsaicin-sensitive peptidergic sensory nerves were defunctionalized by resiniferatoxin (RTX) pretreatment 2 weeks earlier, in a separate group animals were treated with the somatostatin receptor antagonist cyclo-somatostatin (C-SOM). Plasma SST-LI significantly elevated in septic patients compared to healthy volunteers during the whole 4-day period. Significantly decreased Horowitz score showed severe lung injury, increased plasma C-reactive protein and procalcitonin confirmed SIRS. Soluble P-selectin, tissue plasminogen activator and the interleukin 8 and monocyte chemotactic protein-1 significantly increased, interleukin 6 and soluble CD40 ligand did not change, and soluble Vascular Adhesion Molecule-1 decreased. SST-LI significantly increased in rats both in the plasma and the lung 6h after CLP compared to sham-operation. After RTX pretreatment SST-LI was not altered in intact animals, but the SIRS-induced elevation was absent. Lung MPO activity significantly increased 6h following CLP compared to sham operation, which was significantly higher both after RTX-desensitization and C-SOM-treatment. Most non-pretreated operated rats survived the 6h, but 60% of the RTX-pretreated ones died showing a significantly worse survival. This is the first comprehensive study in humans and animal experiments providing evidence that SST is released from the activated peptidergic sensory nerves. It gets into the bloodstream and mediates a potent endogenous protective mechanism.

Identifying sepsis too late

Sepsis campaign awareness and adherence to the SSC bundles remain a challenge for many healthcare providers causing wide-ranging results, but hospitals are consistently reporting reduced sepsis-related mortality associated with adherence to the SSC guidelines. This case study is likely very similar to many of the other hundreds of thousands of people who died of sepsis in 2010. Would following the SSC guidelines have made a difference for this patient? It’s difficult to know for sure, but this case illustrates the importance of remaining in formed about the latest research and guidelines in healthcare. Visit www.surviving sepsis.org to learn more about the guidelines for treating sepsis.

Active von Willebrand factor predicts 28-day mortality in patients with systemic inflammatory response syndrome

Endothelial dysfunction contributes to the pathology of systemic inflammatory response syndrome (SIRS). However, endothelial biomarkers are not routinely evaluated in this setting. Here, 275 patients with SIRS and plasma levels of von Willebrand factor (VWF), thrombospondin-1, myeloperoxidase, ADAMTS-13, and active VWF (aVWF) were studied in relation to 28-day mortality. On admission, aVWF levels were higher in nonsurvivors vs survivors (0.69 vs 0.47 µg/mL, P = .019). Patients in the highest tertile of aVWF levels had a lower cumulative survival (86% vs 75%, P = .017) and twofold increased hazard ratio (HR). When adjusted for the Acute Physiology and Chronic Health Evaluation IV (APACHE-IV) score, this difference remained significant (HR 1.82, 95% confidence interval, 1.03-3.3). On admission, no significant differences were measured for the other proteins. These observations suggest that the stimulated release of VWF is not predictive for mortality in patients with SIRS, opposite of the processing of VWF after release. aVWF could be used with the APACHE-IV score to stratify SIRS patients at high mortality risk.

The endothelial protein C receptor impairs the antibacterial response in murine pneumococcal pneumonia and sepsis

Pneumococcal pneumonia is a frequent cause of gram-positive sepsis and has a high mortality. The endothelial protein C receptor (EPCR) has been implicated in both the activation of protein C (PC) and the anti-inflammatory actions of activated (A)PC. The aim of this study was to determine the role of the EPCR in murine pneumococcal pneumonia and sepsis. Wild-type (WT), EPCR knockout (KO) and Tie2-EPCR mice, which overexpress EPCR on the endothelium, were infected intranasally (pneumonia) or intravenously (sepsis) with viable Streptococcus pneumoniae and euthanised at 24 or 48 hours after initiation of the infection for analyses. Pneumonia did not alter constitutive EPCR expression on pulmonary endothelium but was associated with an influx of EPCR positive neutrophils into lung tissue. In pneumococcal pneumonia EPCR KO mice demonstrated diminished bacterial growth in the lungs and dissemination to spleen and liver, reduced neutrophil recruitment to the lungs and a mitigated inflammatory response. Moreover, EPCR KO mice displayed enhanced activation of coagulation in the early phase of disease. Correspondingly, in pneumococcal sepsis EPCR KO mice showed reduced bacterial growth in lung and liver and attenuated cytokine release. Conversely, EPCR-overexpressing mice displayed higher bacterial outgrowth in lung, blood, spleen and liver in pneumococcal sepsis. In conclusion, EPCR impairs antibacterial defense in both pneumococcal pneumonia and sepsis, which is associated with an enhanced pro-inflammatory response.

Traumatic coagulopathy--part 1: Pathophysiology and diagnosis

OBJECTIVE

To review the current literature in reference to the pathophysiology and diagnostic modalities available for acute traumatic coagulopathy (ATC) in relationship to traumatic hemorrhagic shock.

ETIOLOGY

Posttraumatic hemorrhage is responsible for one of the leading causes of preventable human deaths worldwide. Acute traumatic coagulopathy is an endogenous hypocoagulable condition that has been observed during the immediate (< 1 hour) posttraumatic period. Phenotypically, ATC manifests as a state of systemic hypocoagulability and hyperfibrinolysis. Although different functional mechanisms have been proposed for causing ATC, it is universally thought to be a manifestation of severe tissue injury, shock-induced hypoperfusion, systemic inflammation, and endothelial damage. Excessive activation of the thrombin-thrombomodulin activated Protein C pathway, catecholamine-induced endothelial damage as well as disseminated intravascular coagulation (DIC) with a fibrinolytic phenotype are all hypotheses that have been proposed in attempts to explain the functional mechanism of ATC.

DIAGNOSIS

An accurate and reliable test remains to be validated for ATC. Traditional coagulation assays (activated partial thromboplastin times and prothrombin times) along with platelet count and fibrinogen concentrations have been used more commonly. Viscoelastic tests (thromboelastography and rotational thromboelastometry) are currently being investigated as a more predictive modality for identifying and guiding therapy for ATC.

THERAPY

Damage control resuscitation and hemostatic resuscitation are gaining favor as the optimal resuscitative strategies for hemorrhagic shock and ATC. Antifibrinolytics may also play a role when hyperfibrinolysis is present.

PROGNOSIS

Massive hemorrhage accounts for 30-56% of prehospital posttraumatic deaths in people, with coagulopathic hemorrhage remaining one of the major causes of preventable deaths within the first 24 hours posttrauma. Ten to twenty-five percent of human trauma patients experience ATC, which has been shown to prolong hemorrhage, deter resuscitative efforts, promote sepsis, and increase mortality by at least 4-fold. Prognosis in veterinary patients is not currently known.

Increased mortality in systemic inflammatory response syndrome patients with high levels of coagulation factor VIIa

BACKGROUND

The tissue factor (TF)- Factor VIIa (FVIIa) complex has a pivotal role in inflammatory and coagulation responses in patients with systemic inflammatory response syndrome (SIRS) and sepsis. Because zymogen FVII (FVII) and FVIIa compete for binding to TF, their plasma levels determine if a catalytically active TF-FVIIa complex will be formed.

OBJECTIVE

To study mortality in SIRS patients as a function of FVIIa and FVII levels in plasma.

METHODS

This was a cohort study of 275 patients presenting with SIRS, aged 18 years or older and with an anticipated Intensive Care Unit (ICU) stay of at least 24 h. FVIIa was measured using a novel, quantitative assay that recognizes FVIIa, but not FVII. All-cause hospital mortality was followed over a period of 60 days.

RESULTS

The percentage of FVII measured as FVIIa was higher in non-survivors than survivors (2.8%, IQR = 1-5.5% vs. 1.5%, IQR = 0.6-3.3%; P = 0.034). High levels of FVIIa were associated with decreased 60-day cumulative survival (62% vs. 81%, P = 0.030); the opposite was observed for FVII (84% vs. 76%, P = 0.039). Patients with high-FVIIa and low-FVII levels had a three-fold increased hazard ratio (HR) compared with the patients that had low-FVIIa and high-FVII levels (HR = 3.24, 95% confidence interval [CI] = 1.41-7.36). This association persisted after adjusting for the APACHE IV score (adjusted HR = 2.75, 95% CI = 1.2-6.27).

CONCLUSIONS

SIRS patients with high-FVIIa and low-FVII on admission have an increased mortality risk, an association that is independent from the parameters included in the APACHE IV score.

An updated review of sepsis for the anesthesiologist

Severe sepsis and septic shock continue to be among of the leading causes of death in intensive care unit patients, carrying an estimated mortality rate between 30% and 50%. This article provides an evidence-based focused review of sepsis, including an update on management strategies based on the most recent guidelines published by the Surviving Sepsis Campaign.

Systemic CD14 inhibition attenuates organ inflammation in porcine Escherichia coli sepsis

Sepsis is an infection-induced systemic inflammatory response syndrome. Upstream recognition molecules, like CD14, play key roles in the pathogenesis. The aim of the present study was to investigate the effect of systemic CD14 inhibition on local inflammatory responses in organs from septic pigs. Pigs (n = 34) receiving Escherichia coli-bacteria or E. coli-lipopolysaccharide (LPS) were treated with an anti-CD14 monoclonal antibody or an isotype-matched control. Lungs, liver, spleen, and kidneys were examined for bacteria and inflammatory biomarkers. E. coli and LPS were found in large amounts in the lungs compared to the liver, spleen, and kidneys. Notably, the bacterial load did not predict the respective organ inflammatory response. There was a marked variation in biomarker induction in the organs and in the effect of anti-CD14. Generally, the spleen produced the most cytokines per weight unit, whereas the liver contributed the most to the total load. All cytokines were significantly inhibited in the spleen. Interleukin-6 (IL-6) was significantly inhibited in all organs, IL-1β and IP-10 were significantly inhibited in liver, spleen, and kidneys, and tumor necrosis factor, IL-8, and PAI-1 were inhibited only in the spleen. ICAM-1 and VCAM-1 was significantly inhibited in the kidneys. Systemic CD14-inhibition efficiently, though organ dependent, attenuated local inflammatory responses. Detailed knowledge on how the different organs respond to systemic inflammation in vivo, beyond the information gained by blood examination, is important for our understanding of the nature of systemic inflammation and is required for future mediator-directed therapy in sepsis. Inhibition of CD14 seems to be a good candidate for such treatment.

Antithrombotic activities of pellitorine in vitro and in vivo

Pellitorine (PLT), an active amide compound, is well known to possess insecticidal, antibacterial and anticancer properties. However, the anti-coagulant functions of PLT are not studied yet. Here, the anticoagulant activities of PLT were examined by monitoring activated partial thromboplastin time (aPTT), prothrombin time (PT), and the activities of cell-based thrombin and activated factor X (FXa). Furthermore, the effects of PLT on the expressions of plasminogen activator inhibitor type 1 (PAI-1) and tissue-type plasminogen activator (t-PA) were tested in tumor necrosis factor (TNF)-α activated human umbilical vein endothelial cells (HUVECs). Treatment with PLT resulted in prolonged aPTT and PT and inhibition of the activities of thrombin and FXa, and PLT inhibited production of thrombin and FXa in HUVECs. And PLT inhibited thrombin-catalyzed fibrin polymerization and platelet aggregation. In accordance with these anticoagulant activities, PLT elicited anticoagulant effects in mouse. In addition, treatment with PLT resulted in the inhibition of TNF-α-induced production of PAI-1 and in the significant reduction of the PAI-1 to t-PA ratio. Collectively, PLT possesses antithrombotic activities and offers bases for development of a novel anticoagulant.

Antithrombotic activities of oroxylin A in vitro and in vivo

Here, the anticoagulant activities of oroxylin A (OroA), a major component of Scutellaria baicalensis Georgi, were examined by monitoring activated partial thromboplastin time (aPTT), prothrombin time (PT), and the activities of cell-based thrombin and activated factor X (FXa). Furthermore, the effects of OroA on the expressions of plasminogen activator inhibitor type 1 (PAI-1) and tissue-type plasminogen activator (t-PA) were tested in tumor necrosis factor (TNF)-α activated human umbilical vein endothelial cells (HUVECs). Treatment with OroA resulted in prolonged aPTT and PT and inhibition of the activities of thrombin and FXa, and OroA inhibited production of thrombin and FXa in HUVECs. And OroA inhibited thrombin-catalyzed fibrin polymerization and platelet aggregation. In accordance with these anticoagulant activities, OroA elicited anticoagulant effects in mouse. In addition, treatment of OroA resulted in the inhibition of TNF-α-induced production of PAI-1, and treatment with OroA resulted in the significant reduction of the PAI-1 to t-PA ratio. Collectively, OroA possess antithrombotic activities and offer bases for development of a novel anticoagulant.