Time course of hemostatic abnormalities in sepsis and its relation to outcome

Coagulative Biomarkers Differently Predict Clinical Outcomes in Invasive Infections Caused by Neisseria Meningitidis and Streptococcus Pneumoniae

BACKGROUND

Coagulation plays a crucial role in innate immune response to invasive infections. Coagulative biomarkers might predict clinical outcomes differently, depending on etiology.

METHODS

A retrospective study was conducted during a 79-month period, recruiting 90 patients with meningitis or bloodstream infection caused by Neisseria meningitidis (n = 47) or Streptococcus pneumoniae (n = 43), median age 19 and 58 years, respectively. Biomarkers were assessed within 24 hours.

RESULTS

For N. meningitidis: in univariate analysis, increasing D-dimer was associated with in-hospital mortality (odds ratio [OR] 1.360; 95% confidence interval [CI], 1.063-1.889); in multivariate regression, increasing D-dimer was predictive (OR 1.037; 95% CI, 1.001-1.074) of the composite outcome (in-hospital mortality or amputations or hearing loss or neurological sequelae); protein C showed a clear trend toward lower levels in nonsurvivors (26% vs 48%) and in patients with the composite outcome (32% vs 51%); activated partial thromboplastin time (aPTT) was significantly prolonged in nonsurvivors (51.3 vs 35.3 seconds, P = .003), confirmed in univariate analysis (OR 1.122; 95% CI, 1.031-1.253). For S. pneumoniae: antithrombin was significantly lower in nonsurvivors (70% vs 81%, P = .038), confirmed in univariate analysis (OR 0.961; 95% CI, 0.921-0.997). For overall population: in multivariate regression, increasing age was associated with mortality (OR 1.043; 95% CI, 1.010-1.077), and S. pneumoniae etiology with the composite outcome (OR 6.024; 95% CI, 1.798-20.180).

CONCLUSIONS

For invasive infections caused by N. meningitidis, D-dimer is a biomarker capable of predicting unfavorable clinical outcomes; a potential role is suggested for aPTT prolongation and protein C decrease, and, in case of S. pneumoniae infections, for antithrombin decrease.

Antithrombin and Activated Protein C in Pediatric Sepsis: Prospective Observational Study of Outcome

OBJECTIVES

To assess antithrombin and activated protein C (aPC) levels in relation to disseminated intravascular coagulation (DIC) and severe outcomes in pediatric sepsis.

DESIGN

Prospective, observational study conducted between April 2023 and October 2024. Coagulation profiles including conventional coagulation, antithrombin activity, and aPC were obtained at PICU admission.

SETTING

PICU in the Vietnam National Children's Hospital, Hanoi, Vietnam.

SUBJECTS

PICU admissions, 1 month to 18 years old, with sepsis.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

One hundred thirty children (78 males; median age 7.5 mo) with mortality 23/130 (17.7%). The prevalence of overt DIC was 37 of 130 (28.5%). Nonsurvival at 28 days, compared with survival, was associated with hemorrhage and/or thrombosis at presentation, and higher number of dysfunctional organs, and overt DIC. Those with overt DIC, compared with not, had longer activated partial thromboplastin time, higher international normalized ratio and d -dimer, and lower antithrombin, and aPC. Activity of antithrombin and aPC correlated inversely with the Vasoactive-Inotropic Score in survivors ( p = 0.002 and 0.009, respectively). Patients with a cutoff value for antithrombin less than 63.5% had a mortality risk with area under the receiver operating characteristic (AUROC) curve 0.64, with sensitivity 0.51 and specificity 0.74, and positive predictive value 0.30. Regarding overt DIC, a cutoff value for antithrombin less than 55.5% had an AUROC 0.78, sensitivity 0.72 and specificity of 0.73, and positive predictive value 0.52.

CONCLUSIONS

In this observational study of pediatric sepsis patients, first 24-hour coagulation data in those who did not-survive to 28 days, vs. survivors showed an associated prior lower level of antithrombin in nonsurvivors. Furthermore, using the outcome of overt DIC and nonovert DIC in the first 72 hours, we found that lower levels of antithrombin or aPC are each associated with overt DIC and nonovert DIC in pediatric sepsis. Further validation work is needed in larger case series of pediatric sepsis.

Prognostic significance of fibrinogen levels in sepsis-associated acute kidney injury: unveiling a nonlinear relationship and clinical implications

Background

Fibrinogen plays a pivotal role in the inflammatory cascade and is intricately linked to the pathogenesis of sepsis. Nevertheless, its significance as a prognostic marker for sepsis-associated acute kidney injury (SA-AKI) remains uncertain. This study aimed to investigate the association between fibrinogen levels and 28-day mortality with sepsis-associated acute kidney injury.

Method

The fibrinogen levels of patients admitted to the intensive care unit of Beth Israel Deaconess Medical Center between 2008 and 2019 were retrospectively assessed, and those diagnosed with SA-AKI were divided into low, middle and high fibrinogen level groups according to tertiles. Multivariate Cox proportional hazards model was used to assess the 28-day mortality risk of the SA-AKI patients.

Results

A total of 3,479 patients with SA-AKI were included in the study. Fibrinogen demonstrated an independent association with 28-day mortality, yielding a hazard ratio (HR) of 0.961 (95% confidence interval [CI]: 0.923-0.999, P = 0.0471). Notably, a non-linear relationship between fibrinogen levels and 28-day mortality was observed, with the threshold observed at approximately 1.6 g/l. The effect sizes and corresponding CIs below and above this threshold were 0.509 (0.367, 0.707) and 1.011 (0.961, 1.064), respectively. Specifically, the risk of mortality among SA-AKI patients decreased by 49.1% for every 1 g/l increment in fibrinogen, provided that fibrinogen levels were less than 1.6 g/l.

Conclusion

In patients with SA-AKI, a non-linear relationship was identified between fibrinogen levels and 28-day mortality. Particularly, when their fibrinogen levels were less than 1.6 g/l, a concomitant decrease in 28-day mortality was observed as fibrinogen levels increased.

Risk Factors for Mortality in Critically Ill Patients with Coagulation Abnormalities: A Retrospective Cohort Study

OBJECTIVE

Coagulation abnormalities are common and prognostically significant in intensive care units (ICUs) and are associated with increased mortality. This study aimed to explore the association between the levels of coagulation markers and the risk of mortality among ICU patients with coagulation abnormalities.

METHODS

This retrospective study investigated patients with coagulation abnormalities in the ICU between January 2021 and December 2022. The initial point for detecting hemostatic biomarkers due to clinical assessment of coagulation abnormalities was designated day 0. Patients were followed up for 28 days, and multivariate logistic regression analysis was utilized to identify risk factors for mortality.

RESULTS

Of the 451 patients analyzed, 115 died, and 336 were alive at the end of the 28-day period. Multivariate analysis revealed that elevated thrombin-antithrombin complex (TAT), tissue plasminogen activator inhibitor complex (tPAIC), prolonged prothrombin time, and thrombocytopenia were independent risk factors for mortality. For nonovert disseminated intravascular coagulation (DIC) patients, older age and thrombocytopenia were associated with increased risks of mortality, whereas elevated levels of plasmin α2-plasmin inhibitor complex (PIC) were found to be independent predictors of survival. In patients with overt DIC, elevated levels of tPAIC were independently associated with increased risks of mortality. Nevertheless, thrombocytopenia was independently associated with increased risks of mortality in patients with pre-DIC.

CONCLUSION

Coagulation markers such as the TAT, tPAIC, PIC, and platelet count were significantly associated with mortality, underscoring the importance of maintaining a balance between coagulation and fibrinolysis. These findings highlight the potential for targeted therapeutic interventions based on specific coagulation markers to improve patient outcomes.

Fibrinogen reflects severity and predicts outcomes in patients with sepsis and septic shock

The study investigates the diagnostic and prognostic value of fibrinogen and the albumin-to-fibrinogen-ratio (AFR) in patients with sepsis and septic shock. Limited data regarding the prognostic value of fibrinogen and AFR during the course of sepsis or septic shock are available. Consecutive patients with sepsis and septic shock from 2019 to 2021 were included monocentrically. Blood samples were retrieved from the day of disease onset (day 1), as well as on day 2 and 3. Firstly, the diagnostic value of fibrinogen and the AFR for the diagnosis of a septic shock was tested. Secondly, the prognostic value of fibrinogen and AFR was tested with regard to the 30-day all-cause mortality. Statistical analyses included univariable t-tests, Spearman's correlations, C-statistics, Kaplan-Meier and multivariable Cox regression analyses. Ninety-one patients with sepsis and septic shock were included. With an area under the curve (AUC) of 0.653-0.801, fibrinogen discriminated patients with septic shock from those with sepsis. In the septic shock group, fibrinogen levels were shown to decrease from day 1 to 3 (median decrease 41%). In line, fibrinogen was a reliable predictor for 30-day all-cause mortality (AUC 0.661-0.744), whereas fibrinogen levels less than 3.6 g/l were associated with an increased risk of 30-day all-cause mortality (78 vs. 53%; log rank P  = 0.004; hazard ratio = 2.073; 95% confidence interval 1.233-3.486; P  = 0.006), which was still observed after multivariable adjustment. In contrast, the AFR was no longer associated with the risk of mortality after multivariable adjustment. Fibrinogen was a reliable diagnostic and prognostic tool for the diagnosis of septic shock as well as for 30-day all-cause mortality and superior compared with the AFR in patients admitted with sepsis or septic shock.

Fibrinogen Is Associated with Prognosis of Critically Ill Patients with Sepsis: A Study Based on Cox Regression and Propensity Score Matching

Introduction

Sepsis is a common syndrome in critically ill patients. Fibrinogen was reported to be associated with the prognosis of sepsis patients.

Materials and Methods

Data was acquired from Multiparameter Intelligent Monitoring in Intensive Care Database IV (MIMIC-IV) version 1.0. Cox proportional hazards regression was utilized to estimate the relationship between fibrinogen and inhospital mortality. The cumulative incidence of mortality by fibrinogen level was estimated through the Kaplan-Meier curve. Restricted cubic spline (RCS) was used to assess nonlinear relationship. Subgroup analysis was also conducted to evaluate the robustness of the association between fibrinogen and inhospital mortality. Propensity score matching (PSM) was applied to adjust for confounding factors.

Results

A total of 3365 patients, including 2031 survivors and 1334 nonsurvivors, were enrolled in our study. The survivors had a significantly elevated levels of fibrinogen compared with the deceased. The elevated level of fibrinogen was significantly associated with a decrease in mortality in multivariate Cox regression before and after PSM (HR 0.66, P < 0.001 and HR 0.73, P < 0.001, respectively). RCS showed a nearly linear relationship. Subgroup analysis demonstrated the robustness of the association in most subpopulations. However, the association between decreased levels of fibrinogen and increased inhospital mortality was denied after PSM.

Conclusion

The elevated level of fibrinogen hints at better overall survival in critically ill patients with sepsis. Decreased levels of fibrinogen may be of little value in identifying patients with a high risk of death.

Protein C activity as a potential prognostic factor for nursing home-acquired pneumonia

Introduction

Despite the poor prognosis for nursing home acquired pneumonia (NHAP), a useful prognostic factor is lacking. We evaluated protein C (PC) activity as a predictor of in-hospital death in patients with NHAP and community-acquired pneumonia (CAP).

Methods

This prospective, observational study included all patients hospitalized with pneumonia between July 2007 and December 2012 in a single hospital. We measured PC activity at admission and investigated whether it was different between survivors and non-survivors. We also examined whether PC activity < 55% was a predictor for in-hospital death of pneumonia by logistic regression analysis with CURB-65 items (confusion, blood urea >20 mg/dL, respiratory rate >30/min, and blood pressure <90/60 mmHg, age >65). When it was a useful prognostic factor for pneumonia, we combined PC activity with the existing prognostic scores, the pneumonia severity index (PSI) and CURB-65, and analyzed its additional effect by comparing the areas under the receiver operating characteristic curves (AUCs) of the modified and original scores.

Results

Participants comprised 75 NHAP and 315 CAP patients. PC activity was lower among non-survivors than among survivors in NHAP and all-pneumonia (CAP+NHAP). PC activity <55% was a useful prognostic predictor for NHAP (Odds ratio 7.39 (95% CI; 1.59–34.38), and when PSI or CURB-65 was combined with PC activity, the AUC improved (from 0.712 to 0.820 for PSI, and 0.657 to 0.734 for CURB-65).

Conclusions

PC activity was useful for predicting in-hospital death of pneumonia, especially in NHAP, and became more useful when combined with the PSI or CURB-65.

Fibrin structure, viscoelasticity and lysis face the interplay of biorelevant polyions

PURPOSE OF REVIEW

In the past 5 decades, heparins have been widely used as anticoagulants in the prevention and treatment of thrombosis. Subsequent development of heparin variants of various size and charge facilitated the discovery of their multiple biological actions and nonanticoagulant benefits. Platelet-derived or microbial polyphosphates, as well as DNA released in the course of neutrophil extracellular trap-formation are additional polyanions, which can modulate the development and stability of thrombi associated with cancer or inflammation. In this review, we focus on the size-dependent and electric charge-dependent modulatory effects of the three polyanions of different chemical structure.

RECENT FINDINGS

The polycationic histones have been recognized as potential biomarkers and therapeutic targets in several diseases related to inflammation and thrombosis. Since combating histones with activated protein C or heparin could cause unwanted bleeding, the quest for nonanticoagulant histone-neutralizing agents is ongoing. Polyanions may neutralize or exaggerate certain histone-mediated effects depending on their electric charge, size and histone effects under investigation. Several prothrombotic effects of polyphosphates and DNA are also size-dependent.

SUMMARY

The efficiency of future therapeutics targeting prothrombotic polyanions or histones is not a simple matter of electric charge, but may rely on a delicate combination of size, charge and chemical composition.

Protein C activity in dogs with gastric dilatation and volvulus

Protein C activity, a novel prognostic marker, was evaluated in patients with gastric dilatation and volvulus in relation to mortality and severity of the disease. Data on the mortality, duration of clinical signs, degree of gastric torsion, gastric necrosis, splenectomy and occurrence of disseminated intravascular coagulopathy were recorded. Blood samples were obtained at selected time periods: T0 = no longer than 30 min before surgery; T1 = first day after surgery; T2 = second day after surgery. In addition to protein C activity assessment, haematological and haemostaseological analysis was also performed. The mean protein C activity was the lowest at T1 and the highest at T2. No significant relationship between protein C activity and mortality, duration of clinical signs, degree of gastric torsion, gastric necrosis, splenectomy and disseminated intravascular coagulopathy was found in patients with gastric dilatation and volvulus. All patients that died during hospitalisation after surgery were patients with decreased protein C activity at T1. Although protein C activity was not found to be a reliable preoperative prognostic marker in patients with gastric dilatation and volvulus, the study results show it might be a promising marker in postoperative monitoring of these patients.

The prognostic utility of protein C as a biomarker for adult sepsis: a systematic review and meta-analysis

Background

Sepsis, the dysregulated host response to infection, triggers abnormal pro-coagulant and pro-inflammatory host responses. Limitations in early disease intervention highlight the need for effective diagnostic and prognostic biomarkers. Protein C’s role as an anticoagulant and anti-inflammatory molecule makes it an appealing target for sepsis biomarker studies. This meta-analysis aims to assess the diagnostic and prognostic value of protein C (PC) as a biomarker for adult sepsis.

Methods

We searched MEDLINE, PubMed, EMBASE, CINAHL and Cochrane Library from database inception to September 12, 2021. We included prospective observational studies of (1) adult patients (> 17) with sepsis or suspicion of sepsis that; (2) measured PC levels with 24 h of study admission with; and (3) the goal of examining PC as a diagnostic or prognostic biomarker. Two authors screened articles and conducted risk of bias (RoB) assessment, using the Quality in Prognosis Studies (QUIPS) and the Quality Assessment in Diagnostic Studies-2 (QUADAS-2) tools. If sufficient data were available, meta-analysis was conducted to estimate the standardized mean difference (SMD) between patient populations.

Results

Twelve studies were included, and 8 were synthesized for meta-analysis. Pooled analysis demonstrated moderate certainty of evidence that PC levels were less reduced in sepsis survivors compared to non-survivors (6 studies, 741 patients, SMD = 0.52, 95% CI 0.24–0.81, p = 0.0003, I² = 55%), and low certainty of evidence that PC levels were less reduced in septic patients without disseminated intravascular coagulation (DIC) compared to those with DIC (3 studies, 644 patients, SMD = 0.97, 95% CI 0.62–1.32, p < 0.00001, I² = 67%). PC could not be evaluated as a diagnostic tool due to heterogeneous control populations between studies.

Conclusion and relevance

Our review demonstrates that PC levels were significantly higher in sepsis survivors compared to non-survivors and patients with sepsis but not disseminated intravascular coagulation (DIC). Our evaluation is limited by high RoB in included studies and poor reporting of the sensitivity and specificity of PC as a sepsis biomarker. Future studies are needed to determine the sensitivity and specificity of PC to identify its clinical significance as a biomarker for early sepsis recognition.

Trial Registration PROSPERO registration number: CRD42021229786. The study protocol was published in BMJ Open.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13054-022-03889-2.

Burn-Induced Coagulopathies: a Comprehensive Review

Burn-induced coagulopathy is not well understood, and consensus on diagnosis, prevention, and treatments are lacking. In this review, literature on burn-induced (and associated) coagulopathy is presented along with the current understanding of the effects of burn injury on the interactions among coagulation, fibrinolysis, and inflammation in the acute resuscitative phase and reconstructive phase of care. The role of conventional tests of coagulopathy and functional assays like thromboelastography or thromboelastometry will also be discussed. Finally, reported methods for the prevention and treatment of complications related to burn-induced coagulopathy will be reviewed.

Fibrinolytic Alterations in Sepsis: Biomarkers and Future Treatment Targets

Sepsis is a life-threatening condition which develops as a dysregulated immune response in the face of infection and which is associated with profound hemostatic disturbances and in the most extreme cases disseminated intravascular coagulation (DIC). In addition, the fibrinolytic system is subject to alterations during infection and sepsis, and impaired fibrinolysis is currently considered a key player in sepsis-related microthrombus formation and DIC. However, we still lack reliable biomarkers to assess fibrinolysis in the clinical setting. Furthermore, drugs targeting the fibrinolytic system have potential value in sepsis patients with severe fibrinolytic disturbances, but these are still being tested in the preclinical stage. The present review provides an overview of key fibrinolytic changes in sepsis, reviews the current literature on potential laboratory markers of altered fibrinolysis in adult sepsis patients, and discusses future perspectives for diagnosis and treatment of fibrinolytic disturbances in sepsis patients.

Understanding the andromeda strain - The role of cytokine release, coagulopathy and antithrombin III in SARS-CoV2 critical illness

As the current coronavirus pandemic continues and cases of COVID-19 critical illness rise, physicians and scientists across the globe are working to understand and study its pathophysiology. Part of the pathology of this illness may result from its prothrombotic potential as witnessed from derangements in coagulation and thrombotic complications reported in observational studies performed in China and Europe to findings of microthrombosis upon autopsy analysis of patients who succumbed to COVID-19. Multiple organizations, including the American Society of Hematology (ASH), recommend the routine use of prophylactic heparin to temper the thrombotic complications of this illness given its mortality benefit in severe COVID-19 infections. Reductions in circulating levels of Antithrombin III (AT), the primary mediator of heparin's action, is present in cases of coronavirus related critical illness. AT's use as a prognostic marker, an important effector of heparin resistance, and a potential therapeutic target for COVID-19 remains to be explored.

The association between plasminogen activator inhibitor type-1 and clinical outcome in paediatric sepsis

: Acute phase protein plasminogen activator inhibitor type-1 (PAI-1) is a key element in fibrinolysis inhibition in sepsis-induced disseminated intravascular coagulation (DIC). Elevated PAI-1 level is related to worse outcome in sepsis. The aim of this study was to investigate the relationship between plasma PAI-1 level and clinical outcome in children with sepsis. A total of 35 children with sepsis were enrolled into this prospective study. Plasma PAI-1 was measured on day-1 and day-4. Systemic coagulation profile was measured on day-4. Individuals were followed up until 28 days. The mean PAI-1 from day-1 to day-4 in overt DIC children was not statistically significant. Contrarily, among nonovert DIC individuals, there was a significant difference (P ≤ 0.001) in PAI-1 levels on day-1 compared with day-4 were 95.25 ± 46.57 vs. 60.36 ± 37.31 ng/ml, respectively. Among survivors, mean PAI-1 level on day-1 was statistically higher than PAI-1 level on day-4 (82.47 ± 44.43 vs. 58.39 ± 32.98 ng/ml), P = 0.021. There was no significant difference between PAI-1 levels on day-1 compared with day-4 in nonsurvivors. PAI-1 was correlated to DIC score with r = 0.606 (P ≤ 0.001). PAI-1 levels significantly decreased on day-4 compared with day-1 among nonovert DIC individuals, and not in overt DIC individuals. Changes in PAI-1 levels in nonsurvivors did not differ. PAI-1 level was positively correlated with DIC score.

Fibrinogen as a Prognostic Predictor in Pediatric Patients with Sepsis: A Database Study

Background

Systemic inflammatory response and vascular endothelial cell injury during sepsis lead to coagulopathy. Fibrinogen has been reported as a biomarker of coagulopathy; however, the prognostic value of fibrinogen remains undefined in pediatric patients with sepsis. The aim of this study was to assess fibrinogen level on pediatric intensive care unit (PICU) admission and to elucidate the relationship between fibrinogen levels and in-hospital mortality in children with sepsis.

Methods

We conducted a database study. The sepsis database was divided into a training set (between July 2014 and June 2018) and a validation set (from July 2018 to June 2019). The clinical and laboratory parameters on PICU admission and in-hospital mortality in sepsis database were collected and analyzed.

Results

A total of 819 pediatric patients were included from database as a training set. The overall hospital mortality was 12.1% (99/819). The fibrinogen levels were significantly lower in nonsurvivors than survivors. Multivariate logistic regression analysis showed significant associations between fibrinogen, lactate level, and hospital mortality (fibrinogen: odds ratio (OR), 0.767 (95% CI: 0.628-0.937), P = 0.009; lactate: OR, 1.346 (95% CI: 1.217-1.489), P < 0.001, respectively), which was confirmed in a validation set (0.616 [95% CI: 0.457-0.829], P = 0.001; 1.397 [95% CI: 1.245-1.569], P < 0.001, respectively). The hospital mortality of patients with fibrinogen < 1 g/L, 1-2 g/L, 2-3 g/L, or over 3 g/L displayed an obvious difference (62.5% vs. 27.66% vs. 18.1% vs. 4.2%, respectively). Furthermore, the area under the receiver operating characteristic curve (ROC) for fibrinogen in predicting hospital mortality was 0.780 (95% CI: 0.711-0.850) in pediatric patients with sepsis.

Conclusions

Fibrinogen is a valuable prognostic biomarker for pediatric sepsis. The level of fibrinogen lower than 2 g/L on PICU admission is closely related to the greater risk of hospital death in pediatric sepsis.

Effect of therapeutic plasma exchange on endothelial activation and coagulation-related parameters in septic shock

Background

A dysbalanced coagulation system is part of the pathological host response to infection in sepsis. Activation of pro-coagulant pathways and attenuation of anti-coagulant activity ultimately lead to microvascular stasis and consequent organ failure. No treatment approaches specifically targeting this axis are available. We explored the effects of therapeutic plasma exchange (TPE) on microvascular coagulation dysbalance in septic shock.

Methods

We conducted a prospective single-center study enrolling 31 patients with early septic shock (onset < 12 h) requiring high doses of norepinephrine (NE > 0.4 μg/kg/min). Clinical and biochemical data, including measurement of protein C; a disintegrin and metalloprotease with a thrombospondin type 1 motif, member 13 (ADAMTS13); and von Willebrand factor antigen (vWF:Ag), were obtained before and after TPE against fresh frozen plasma.

Results

Antithrombotic acting proteins such as antithrombin-III (ATIII) and protein C were markedly reduced in septic patients, but their activity increased after TPE (ATIII, 51% (41–61) vs. 63% (48–70), p = 0.029; protein C, 47% (38–60) vs. 62% (54–69), p = 0.029). Median ADAMTS13 activity was increased by TPE from 27 (21–42) % before to 47 (38–62) % after TPE (p < 0.001). In contrast, vWF:Ag was elevated and could be reduced by TPE (353 (206–492) IU/dL vs. 170 (117–232) IU/dL, p < 0.001). Regression analysis yielded a correlation between ADAMTS13 activity and platelet count (p = 0.001, R² = 0.316).

Conclusions

Septic shock was associated with activation of pro-coagulant pathways and simultaneous depletion of anti-coagulant factors. TPE partially attenuated this dysbalance by removing pro- and by replacing anti-coagulant factors.

Trial registration

ClinicalTrials.gov, NCT03065751. Retrospectively registered on 28 February 2017.

Significance of plasma fibrinogen level and antithrombin activity in sepsis: A multicenter cohort study using a cubic spline model

INTRODUCTION

Sepsis leads to coagulopathy by the activation of inflammatory mediators and vascular endothelial cell injury. A number of biomarkers are used to evaluate coagulopathy on sepsis. Fibrinogen and antithrombin activity have been reported as biomarkers of coagulopathy; however, the utility of these two markers has not been well established. This study aimed to evaluate the detailed association between these two markers and clinical outcomes in sepsis patients.

MATERIALS AND METHODS

This was a post hoc analysis of a multicenter, prospective cohort study conducted in 59 intensive care units throughout Japan from January 2016 to March 2017. We included 1103 adult patients with severe sepsis based on the Sepsis-2 criteria. The associations between the coagulation markers and in-hospital mortality were examined using linear and non-linear logistic regression analyses. We also evaluated the associations between the coagulation markers and disseminated intravascular coagulation (DIC) scores. The International Society on Thrombosis and Haemostasis overt DIC score was calculated after subtracting the fibrinogen component.

RESULTS

The decreased levels of the fibrinogen and antithrombin activity were significantly associated with an increase in mortality (P = 0.011 and 0.002, respectively). In addition, cubic spline regression demonstrated that mortality sharply increased at a fibrinogen level of approximately <200 mg/dL and at an antithrombin activity of approximately <50%. Similarly, the decreased levels of the two markers non-linearly correlated with the elevation of DIC score.

CONCLUSIONS

The fibrinogen level and antithrombin activity should be reconsidered as unique biomarkers for sepsis and sepsis-induced DIC.

Variation of endothelium-related hemostatic factors during sepsis

OBJECTIVE

The thrombomodulin/protein C and VWF/ADAMTS-13 pathways are disturbed in sepsis and have been implicated in the coagulation disorders that characterize the septic syndrome. We aimed to assess the variation of these endothelial parameters during sepsis and their putative association with outcome, in critically ill, septic patients.

METHODS

We monitored 34 septic patients, 23 of whom improved (group A) while 11 deteriorated (group B). We assessed ADAMTS-13 levels, VWF activity, soluble thrombomodulin, and protein C activity upon admission to the ICU (time point 0) and at the time of a change in the clinical condition (remission or deterioration, time point 1).

RESULTS

In group A, thrombomodulin and VWF increased at time point 1 compared to time point 0 (P = 0.011, P = 0.028, respectively). In group B, protein C and ADAMTS-13 significantly decreased (P = 0.023, P = 0.026, respectively), while VWF, VWF/ADAMTS-13 ratio, and the thrombomodulin/protein C ratio increased (P = 0.02, P = 0.002, P = 0.01, respectively). Protein C (> or ≤17%) and ADAMTS-13 percentage difference (> or ≤22%) were independently associated with sepsis outcome among the endothelial variables tested.

CONCLUSIONS

An ongoing endothelial/hemostatic disorder was established during sepsis, observed even at clinical improvement. Among the variables tested, protein C and ADAMTS-13 change were associated with outcome.

Clinical, laboratory, and hemostatic findings in cats with naturally occurring sepsis

OBJECTIVE To characterize clinical and laboratory findings in cats with naturally occurring sepsis, emphasizing hemostasis-related findings, and evaluate these variables for associations with patient outcomes. DESIGN Prospective, observational, clinical study. ANIMALS 31 cats with sepsis and 33 healthy control cats. PROCEDURES Data collected included history; clinical signs; results of hematologic, serum biochemical, and hemostatic tests; diagnosis; and outcome (survival vs death during hospitalization or ≤ 30 days after hospital discharge). Differences between cats with and without sepsis and associations between variables of interest and death were analyzed statistically. RESULTS The sepsis group included cats with pyothorax (n = 10), septic peritonitis (7), panleukopenia virus infection (5), bite wounds (5), abscesses and diffuse cellulitis (3), and pyometra (1). Common clinical abnormalities included dehydration (21 cats), lethargy (21), anorexia (18), pale mucous membranes (15), and dullness (15). Numerous clinicopathologic abnormalities were identified in cats with sepsis; novel findings included metarubricytosis, hypertriglyceridemia, and high circulating muscle enzyme activities. Median activated partial thromboplastin time and plasma D-dimer concentrations were significantly higher, and total protein C and antithrombin activities were significantly lower, in the sepsis group than in healthy control cats. Disseminated intravascular coagulopathy was uncommon (4/22 [18%] cats with sepsis). None of the clinicopathologic abnormalities were significantly associated with death on multivariate analysis. CONCLUSIONS AND CLINICAL RELEVANCE Cats with sepsis had multiple hematologic, biochemical, and hemostatic abnormalities on hospital admission, including several findings suggestive of hemostatic derangement. Additional research including larger numbers of cats is needed to further investigate these findings and explore associations with outcome.

Early identification of patients at risk for acute respiratory distress syndrome among severe pneumonia: a retrospective cohort study

Background

Severe pneumonia is the predominant cause for acute respiratory distress syndrome (ARDS). Identification of ARDS from patients with severe pneumonia remains a significant clinical problem due to the overlap of clinical presentations and symptoms. Early recognition of risks for ARDS from severe pneumonia is of great clinical value.

Methods

From April 2014 to December 2015, patients with severe pneumonia at admission were retrieved from the hospital database, of which ARDS developed within 7 days were further identified. We compared the demographic and clinical characteristics at admission between severe pneumonia patients with and without ARDS development, followed by analysis of potential predictors for ARDS development and mortality. Multivariate logistic regression and receiver operating characteristic (ROC) curves were performed to screen independent risk factors and identify their sensitivity in predicting ARDS development and prognosis.

Results

Compared with severe pneumonia without ARDS development, patients with ARDS development had shorter disease duration before admission, higher lung injury score (LIS), serum fibrinogen (FiB), and positive end-expiratory pressure (PEEP), lower Marshall score, sequential organ failure assessment score and proportion of cardiovascular and gastrointestinal diseases, but similar mortality. Serum FiB >5.15 g/L [adjusted odds ratio (OR) 1.893, 95% confidence interval (CI): 1.141-3.142, P=0.014] and PEEP >6.5 cmH₂O (adjusted OR 1.651, 95% CI: 1.218-2.237, P=0.001) were independent predictors for ARDS development with a sensitivity of 58.3% and 87.5%, respectively, and pH <7.35 (adjusted OR 0.832, 95% CI: 0.702-0.985, P=0.033) was an independent risk factor for ARDS mortality with a sensitivity of 95.2%.

Conclusions

ARDS development risk could be early recognized by PEEP >6.5 cmH₂O and serum FiB >5.15 g/L in severe pneumonia patients, and pH <7.35 is a reliable prognostic factor in predicting ARDS mortality risk.

Endothelial protein C receptor-dependent antichemotactic effects of canine protein C

OBJECTIVE To determine whether canine protein C (CnPC) had antichemotactic effects on canine neutrophils, whether endothelial protein C receptor (EPCR) was expressed on canine neutrophils, and the role of EPCR in neutrophil chemotaxis. SAMPLE Neutrophils isolated from blood samples from healthy dogs (n = 6) and sick dogs with (2) or without (3) an inflammatory leukogram. PROCEDURES Neutrophils were analyzed by reverse transcriptase PCR assay and flow cytometry for detection of EPCR mRNA and protein expression, respectively. Neutrophils were incubated with CnPC zymogen or canine activated protein C (CnAPC), with or without RCR-379 (an anti-human EPCR antibody). Neutrophils were then allowed to migrate through a filter membrane toward a chemokine. Untreated neutrophils served as positive control samples. Migration was quantified by fluorescence measurement, and chemotaxis index (Chx) values (fluorescence of test sample/fluorescence of positive control sample) were computed. RESULTS The cDNA for EPCR was amplified, and EPCR expression was detected on neutrophil surfaces. Obtained Chx values were significantly higher in cells treated with RCR-379 than in cells treated with CnPC or CnAPC alone. The Chx values for neutrophils treated with RCR-379 were not significantly different from 1, whereas those for neutrophils treated without RCR-379 were significantly less than 1. The effects of RCR-379 on neutrophil migration were independent of concentration or activation status of protein C. CONCLUSIONS AND CLINICAL RELEVANCE Canine neutrophils expressed EPCR, and inhibition of neutrophil chemotaxis by CnPC and CnAPC depended on EPCR. Interventions with EPCR signaling may have therapeutic application in dogs.

Evening primrose oil or forskolin ameliorates celecoxib-enhanced upregulation of tissue factor expression in mice subjected to lipopolysaccharide-induced endotoxemia

Celecoxib, a selective cyclooxygenase-2 inhibitor, produces thrombotic events in patients predisposed to cardiovascular risk factors. One theory reported an increase in endothelial expression of tissue factor (TF) as a predisposing factor. This work explored the effect of evening primrose oil (EPO), a source of prostaglandin E1, and forskolin (a cyclic adenosine monophosphate stimulator) against the prothrombotic effect of celecoxib in mice. Lipopolysaccharide mouse model of endotoxemia was used to induce an upregulation of TF activity. Male mice received celecoxib (25 mg/kg), celecoxib plus EPO, or celecoxib plus forskolin for 4 weeks and then subjected to a prothrombotic challenge in the form of an intraperitoneal injection of lipopolysaccharide. Results showed an increase in plasma TF activity, endothelial TF expression, and thrombin-antithrombin (TAT) but lower antithrombin III (ATIII) level in mice that received celecoxib in comparison to those that received the vehicle. Adding EPO or forskolin to celecoxib regimen significantly decreased the prothrombotic effect of celecoxib. A positive correlation (r = 0.8501) was found between TF activity and TAT. Co-administration of EPO or forskolin decreased the activity of TF and mitigated the prothrombotic effect of celecoxib. Therefore, these combinations may have the utility to abrogate the prothrombotic adverse effect of celecoxib in clinical setting.

Drotrecogin Alfa (Activated) in an Infant with Gram-Negative Septic Shock

The authors observed the effect of drotrecogin alfa (activated) in a case of pediatric severe sepsis. A 4-month-old male infant with Serratia marcescens septic shock, multiple organ dysfunction syndrome (MODS), and consumptive coagulopathy was admitted. The safety and efficacy of drotrecogin alfa (activated) has not yet been established for patients younger than 18 years of age. This is the first published report of the use of drotrecogin alfa (activated) in an infant with severe sepsis. Within 6 hours of starting therapy, there was a significant improvement in hemodynamics, which was not maintained after the drotrecogin alfa (activated) infusion was temporarily discontinued. No significant bleeding complications occurred during the infusion. A brain MRI on day 22 after drotrecogin alfa (activated) infusion showed bilateral small occipital hemorrhages. Drotrecogin alfa (activated) in this infant was temporally related to significant improvement. It is unknown whether the MRI brain lesions are related to severe sepsis with disseminated intravascular coagulation or drotrecogin alfa (activated) infusion. The authors believe that drotrecogin alfa (activated) should be considered in select children with life-threatening severe sepsis.

Coagulation and complement system in critically ill patients

Activation of coagulation and inflammatory response including the complement system play a major role in the pathogenesis of critical illness. However, only limited data are available addressing the relationship of both pathways and its assessment of a predictive value for the clinical outcome in intense care medicine. Therefore, parameters of the coagulation and complement system were studied in patients with septicaemia and multiple trauma regarded as being exemplary for critical illness. 34 patients (mean age: 51.38 years (±16.57), 15 females, 19 males) were investigated at day 1 of admittance to the intensive care unit (ICU). Leukocytes, complement factors C3a and C5a were significantly (p <  0.0500) higher in sepsis than in trauma, whereas platelet count and plasma fibrinogen were significantly lower in multiple trauma. Activation markers of coagulation were elevated in both groups, however, thrombin-antithrombin-complex was significantly higher in multiple trauma. DIC scores of 5 were not exceeded in any of the two groups. Analysing the influences on mortality (11/34; 32.35% ), which was not different in both groups, non-survivors were significantly older, had significantly higher multiple organ failure (MOF) scores, lactate, abnormal prothrombin times and lower C1-inhibitor activities, even more pronounced in early deaths, than survivors. In septic non-survivors protein C was significantly lower than in trauma. We conclude from these data that activation of the complement system as part of the inflammatory response is a significant mechanism in septicaemia, whereas loss and consumption of blood components including parts of the coagulation and complement system is more characteristic for multiple trauma. Protein C in case of severe reduction might be of special concern for surviving in sepsis. Activation of haemostasis was occurring in both diseases, however, overt DIC was not confirmed in this study to be a leading mechanism in critically ill patients. MOF score, lactate, C1-inhibitor and prothrombin time have been the only statistically significant predictors for lethal outcome suggesting that organ function, microcirculation, haemostasis and inflammatory response are essential elements of the pathomechanism and clinical course of diseases among critically ill patients.

Impact of the Pla protease substrate α2-antiplasmin on the progression of primary pneumonic plague

Many pathogens usurp the host hemostatic system during infection to promote pathogenesis. Yersinia pestis, the causative agent of plague, expresses the plasminogen activator protease Pla, which has been shown in vitro to target and cleave multiple proteins within the fibrinolytic pathway, including the plasmin inhibitor α2-antiplasmin (A2AP). It is not known, however, if Pla inactivates A2AP in vivo; the role of A2AP during respiratory Y. pestis infection is not known either. Here, we show that Y. pestis does not appreciably cleave A2AP in a Pla-dependent manner in the lungs during experimental pneumonic plague. Furthermore, following intranasal infection with Y. pestis, A2AP-deficient mice exhibit no difference in survival time, bacterial burden in the lungs, or dissemination from wild-type mice. Instead, we found that in the absence of Pla, A2AP contributes to the control of the pulmonary inflammatory response during infection by reducing neutrophil recruitment and cytokine production, resulting in altered immunopathology of the lungs compared to A2AP-deficient mice. Thus, our data demonstrate that A2AP is not significantly affected by the Pla protease during pneumonic plague, and although A2AP participates in immune modulation in the lungs, it has limited impact on the course or ultimate outcome of the infection.

Sonic Estimation of Elasticity via Resonance: A New Method of Assessing Hemostasis

Uncontrolled bleeding threatens patients undergoing major surgery and in care for traumatic injury. This paper describes a novel method of diagnosing coagulation dysfunction by repeatedly measuring the shear modulus of a blood sample as it clots in vitro. Each measurement applies a high-energy ultrasound pulse to induce a shear wave within a rigid walled chamber, and then uses low energy ultrasound pulses to measure displacements associated with the resonance of that shear wave. Measured displacements are correlated with predictions from finite difference time domain models, with the best fit corresponding to the modulus estimate. In our current implementation each measurement requires 62.4 ms. Experimental data was analyzed using a fixed-viscosity algorithm and a free-viscosity algorithm. In experiments utilizing human blood induced to clot by exposure to kaolin, the free-viscosity algorithm quantified the shear modulus of formed clots with a worst-case precision of 2.5%. Precision was improved to 1.8% by utilizing the fixed-viscosity algorithm. Repeated measurements showed a smooth evolution from liquid blood to a firm clot with a shear modulus between 1.4 and 3.3 kPa. These results show the promise of this technique for rapid, point of care assessment of coagulation.

Assessment of Fibrinolysis in Sepsis Patients with Urokinase Modified Thromboelastography

INTRODUCTION

Impairment of fibrinolysis during sepsis is associated with worse outcome. Early identification of this condition could be of interest. The aim of this study was to evaluate whether a modified point-of-care viscoelastic hemostatic assay can detect sepsis-induced impairment of fibrinolysis and to correlate impaired fibrinolysis with morbidity and mortality.

METHODS

This single center observational prospective pilot study was performed in an adult Intensive Care Unit (ICU) of a tertiary academic hospital. Forty consecutive patients admitted to the ICU with severe sepsis or septic shock were included. Forty healthy individuals served as controls. We modified conventional kaolin activated thromboelastography (TEG) adding urokinase to improve assessment of fibrinolysis in real time (UK-TEG). TEG, UK-TEG, plasminogen activator inhibitor (PAI)-1, thrombin-activatable fibrinolysis inhibitor (TAFI), d-dimer, DIC scores and morbidity (rated with the SOFA score) were measured upon ICU admission. Logistic regression was used to calculate odds ratios (ORs) and 95% confidence intervals (95% CIs) of mortality at ICU discharge.

RESULTS

UK-TEG revealed a greater impairment of fibrinolysis in sepsis patients compared to healthy individuals confirmed by PAI-1. TAFI was not different between sepsis patients and healthy individuals. 18/40 sepsis patients had fibrinolysis impaired according to UK-TEG and showed higher SOFA score (8 (6-13) vs 5 (4-7), p = 0.03), higher mortality (39% vs 5%, p = 0.01) and greater markers of cellular damage (lactate levels, LDH and bilirubin). Mortality at ICU discharge was predicted by the degree of fibrinolysis impairment measured by UK-TEG Ly30 (%) parameter (OR 0.95, 95% CI 0.93-0.98, p = 0.003).

CONCLUSIONS

Sepsis-induced impairment of fibrinolysis detected at UK-TEG was associated with increased markers of cellular damage, morbidity and mortality.

The 4G/4G Genotype of PAI-1 Polymorphism Is Associated with Higher Plasma PAI-1 Concentrations and Mortality in Patients with Severe Sepsis

Objective

Two studies have reported that patients with the 4G/4G genotype of the plasminogen activator inhibitor-1 (PAI-1) genetic polymorphism had higher plasma PAI-1 concentrations and higher risk of death than those with the 4G/5G or 5G/5G genotypes; one study involved 175 children with meningococcal disease, and the other included 88 adult patients with septic shock. Thus, the objective of this study was to determine whether there is an association between carriage of the 4G/4G genotype, plasma PAI-1 concentrations and mortality in a large series of adult septic patients.

Methods

An observational, prospective, multicenter study was carried out in six Spanish Intensive Care Units including severe septic patients. We determined the PAI-1 4G/5G polymorphism and plasma PAI-1 concentrations in all patients. The end-points of the study were 30-day and 6-month mortality.

Results

We included a total of 260 patients, 82 (31.5%) with 4G/4G, 126 (48.5%) with 4G/5G and 52 (20.0%) with 5G/5G genotype. Multivariate logistic regression analysis showed that the 4G/4G genotype was associated with higher mortality at 30 days (Odds Ratio = 1.95; 95% CI = 1.063–3.561; p = 0.03) and at 6 months (Odds Ratio = 2.19; 95% CI = 1.221–3.934; p = 0.01), and that higher plasma PAI-1 concentrations were associated with higher mortality at 30 days (Odds Ratio = 1.01; 95% CI = 1.002–1.022; p = 0.02) at 6 months (Odds Ratio = 1.01; 95% CI = 1.003–1.023; p = 0.01). Multivariate linear regression analysis showed that increased plasma PAI-1 concentrations were associated with the PAI-1 4G/4G genotype (regression coefficient = 4.82; 95% CI = 3.227 to 6.406; p<0.001).

Conclusions

The major findings of our study, to our knowledge the largest series reporting data about 4G/5G polymorphism of the PAI-1 gene, plasma PAI-1 concentrations and mortality in septic patients, were that septic patients with the 4G/4G genotype had higher plasma PAI-1 concentrations and higher risk of death than those with 4G/5G or 5G/5G genotypes.

Pathobiology of acute respiratory distress syndrome

The unique characteristics of pulmonary circulation and alveolar-epithelial capillary-endothelial barrier allow for maintenance of the air-filled, fluid-free status of the alveoli essential for facilitating gas exchange, maintaining alveolar stability, and defending the lung against inhaled pathogens. The hallmark of pathophysiology in acute respiratory distress syndrome is the loss of the alveolar capillary permeability barrier and the presence of protein-rich edema fluid in the alveoli. This alteration in permeability and accumulation of fluid in the alveoli accompanies damage to the lung epithelium and vascular endothelium along with dysregulated inflammation and inappropriate activity of leukocytes and platelets. In addition, there is uncontrolled activation of coagulation along with suppression of fibrinolysis and loss of surfactant. These pathophysiological changes result in the clinical manifestations of acute respiratory distress syndrome, which include hypoxemia, radiographic opacities, decreased functional residual capacity, increased physiologic deadspace, and decreased lung compliance. Resolution of acute respiratory distress syndrome involves the migration of cells to the site of injury and re-establishment of the epithelium and endothelium with or without the development of fibrosis. Most of the data related to acute respiratory distress syndrome, however, originate from studies in adults or in mature animals with very few studies performed in children or juvenile animals. The lack of studies in children is particularly problematic because the lungs and immune system are still developing during childhood and consequently the pathophysiology of pediatric acute respiratory distress syndrome may differ in significant ways from that seen in acute respiratory distress syndrome in adults. This article describes what is known of the pathophysiologic processes of pediatric acute respiratory distress syndrome as we know it today while also presenting the much greater body of evidence on these processes as elucidated by adult and animal studies. It is also our expressed intent to generate enthusiasm for larger and more in-depth investigations of the mechanisms of disease and repair specific to children in the years to come.

The evolution of fibrin-specific targeting strategies

Fibrin-specific targeting capabilities have been highly sought for over 50 years due to their implications for bio-molecule delivery, diagnostics, and regenerative medicine. Yet only recently has our full knowledge of fibrin's complex polymerization dynamics and biological interactions begun to be fully exploited in pursuit of this goal. This highlight will discuss the range of rapidly changing strategies for specifically targeting fibrin over the precursor fibrinogen and the advantages and disadvantages of these approaches for various applications.

Therapeutic angiogenesis improves fibrinolytic imbalance in patients with critical limb ischemia

The mechanisms of fibrinolysis have been suggested to be linked to the pathogenesis of peripheral artery disease. The impact of therapeutic angiogenesis on the parameters of fibrinolysis was studied in critical limb ischemia (CLI). CLI patients (N = 29) and blood donors as controls (N = 29) were enrolled. Bone marrow (600 ± 50 ml) was centrifuged (3200g, 20 min, 22°C), bone marrow-derived mononuclear cells (100-120 ml) were separated by Optipress I and implanted into the ischemic limb using intramuscular injections. ELISA was employed for the assessment of plasma tissue plasminogen activator (t-PA) and plasminogen activator inhibitor-1 (PAI-1) levels. Patients were followed-up prior to the procedure and after 1, 3 and 6 months. All stage-IV patients (N = 22) had ischemic lesions. The lesions resolved in 10 patients. Five patients underwent major amputation; they all were stage-IV. Ischemic lesions persisted in seven patients beyond 6 months. The t-PA levels were higher in patients compared with the healthy controls both at baseline (P < 0.01) and after 6 months (P < 0.05). No significant changes were observed in the t-PA levels during the follow-up. PAI-1 was higher in patients than in the healthy individuals at baseline (P < 0.001) and at month 1 (P < 0.05). However, no difference in PAI-1 levels between the patients and the healthy individuals was found after 3 and 6 months. The PAI-1 levels were significantly downregulated during the follow-up compared with the baseline (P < 0.0001). Therapeutic angiogenesis for the CLI downregulates PAI-1 levels, thus having a systemic effect on fibrinolysis.

Mild induced hypothermia: effects on sepsis-related coagulopathy--results from a randomized controlled trial

INTRODUCTION

Coagulopathy associates with poor outcome in sepsis. Mild induced hypothermia has been proposed as treatment in sepsis but it is not known whether this intervention worsens functional coagulopathy.

MATERIALS AND METHODS

Interim analysis data from an ongoing randomized controlled trial; The Cooling And Surviving Septic shock (CASS) study. Patients suffering severe sepsis/septic shock are allocated to either mild induced hypothermia (cooling to 32-34°C for 24hours) or control (uncontrolled temperature).

TRIAL REGISTRATION

NCT01455116. Thrombelastography (TEG) is performed three times during the first day after study enrollment in all patients. Reaction time (R), maximum amplitude (MA) and patients' characteristics are here reported.

RESULTS

One hundred patients (control n=50 and intervention n=50; male n=59; median age 68years) with complete TEG during follow-up were included. At enrollment, 3%, 38%, and 59% had a hypocoagulable, normocoagulable, and hypercoagulable TEG clot strength (MA), respectively. In the hypothermia group, functional coagulopathy improved during the hypothermia phase, measured by R and MA, in patients with hypercoagulation as well as in patients with hypocoagulation (correlation between ΔR and initial R: rho=-0.60, p<0.0001 and correlation between ΔMA and initial MA: rho=-0.50, p=0.0002). Similar results were not observed in the control group neither for R (rho=-0.03, p=0.8247) nor MA (rho=-0.15, p=0.3115).

CONCLUSION

Mild induced hypothermia did seem to improve functional coagulopathy in septic patients. This improvement of functional coagulopathy parameters during the hypothermia intervention persisted after rewarming. Randomized trials are warranted to determine whether the positive effect on sepsis-related coagulopathy can be transformed to improved survival.

Purification of protein C from canine plasma

Background

In order to characterize the functional properties of canine protein C (CnPC), the zymogen needs to be purified from plasma. The goals of this study were (1) to purify protein C from fresh frozen canine plasma by barium chloride and ammonium sulphate precipitation, followed by immunoaffinity chromatography using a monoclonal mouse antibody against human protein C (HPC4) and (2) to characterize this protein’s structure.

Results

The purified protein contained three glycosylated forms of a heavy chain (~49 kDa) and a glycosylated light chain (~25 kDa). Tandem mass spectra of the peptides obtained following trypsin digestion and liquid chromatography identified this protein to be protein C (vitamin K-dependent protein C precursor, gi|62078422) with 100% probability. Three glycosylation sites (Asn139, Asn202, and Asn350) were identified by detection of peptides containing an N-linked glycosylation consensus sequon with a 3-dalton increase in mass following incubation of the protein with PNGase F in ¹⁸O-labeled water. Following incubation with Protac (a specific activator of protein C), the heavy chain showed a slight decrease in molecular size and amidolytic activity measured by a synthetic chromogenic substrate containing an amide bond [H-D-(γ-carbobenzoxyl)-lysyl-prolyl-arginine-paranitroanilide diacetate salt]. The amidolytic activity was increased by ~303-fold in the final protein preparation compared to that in plasma. The purified protein showed concentration-dependent anti-factor V and anti-factor VIII activities in canine plasma in coagulometric factor assays.

Conclusions

These studies showed that CnPC could be purified from plasma using HPC4 and that this protein showed amidolytic and anti-coagulant properties upon activation with Protac.

Sustained high plasma plasminogen activator inhibitor-1 levels are associated with severity and mortality in septic patients

BACKGROUND

Higher plasma plasminogen activator inhibitor-1 (PAI-1) levels have been reported in septic patients. However, some questions remain unanswered, such as whether there is an association between plasma PAI-1 levels and sepsis severity and mortality, and inflammation state during the first week.

METHODS

Multicenter, observational and prospective study carried out in six Spanish Intensive Care Units of 260 patients with severe sepsis. Circulating levels of PAI-1 and tumour necrosis factor (TNF)-α were measured at day 1, 4 and 8. End-point was 30-day mortality.

RESULTS

Nonsurviving septic patients (n=89) presented higher PAI-1 levels than surviving (n=171) at day 1 (58.4 (33.3-83.8) vs 36.5 (21.1-62.5) ng/mL; p<0.001), 4 (34.0 (14.7-53.3) vs 16.2 (10.2-27.4) ng/mL; p<0.001) and 8 (30.6 (16.2-47.8) vs 18.9 (10.4-29.5) ng/mL; p=0.004). We found a positive correlation of PAI-1 levels with SOFA, lactic acid, aPTT, INR and TNF-α, and negative with platelet count at day 1, 4 and 8. Logistic regression analyses showed that PAI-1 levels at day 1 (p<0.001), 4 (p<0.001) and 8 (p=0.001) were associated with 30-day mortality. On ROC curve analysis to predict 30- day survival, the area under the curve of PAI-1 levels at day 1, 4 and 8 were 0.65 (95% CI=0.58-0.72; p<0.001), 0.69 (95% CI=0.60-0.78; p<0.001) and 0.65 (95% CI=0.54-0.75; p=0.005) respectively.

CONCLUSIONS

The most interesting findings of our study, to our knowledge the largest series reporting PAI-1 levels during follow-up in septic patients, were that plasma PAI-1 levels during the first week were associated with inflammation, severity and mortality.

Combination of thrombin-antithrombin complex, plasminogen activator inhibitor-1, and protein C activity for early identification of severe coagulopathy in initial phase of sepsis: a prospective observational study

Introduction

Current criteria for early diagnosis of coagulopathy in sepsis are limited. We postulated that coagulopathy is already complicated with sepsis in the initial phase, and severe coagulopathy or disseminated intravascular coagulation (DIC) becomes overt after progressive consumption of platelet and coagulation factors. To determine early diagnostic markers for severe coagulopathy, we evaluated plasma biomarkers for association with subsequent development of overt DIC in patients with sepsis.

Methods

A single-center, prospective observational study was conducted in an adult ICU at a university hospital. Plasma samples were obtained from patients with sepsis at ICU admission. Fourteen biomarkers including global markers (platelet count, prothrombin time, activated partial thromboplastin time, fibrinogen and fibrin degradation product (FDP)); markers of thrombin generation (thrombin-antithrombin complex (TAT) and soluble fibrin); markers of anticoagulants (protein C (PC) and antithrombin); markers of fibrinolysis (plasminogen, α₂-plasmin inhibitor (PI), plasmin-α₂-PI complex, and plasminogen activator inhibitor (PAI)-1); and a marker of endothelial activation (soluble E-selectin) were assayed. Patients who had overt DIC at baseline were excluded, and the remaining patients were followed for development of overt DIC in 5 days, and for mortality in 28 days.

Results

A total of 77 patients were enrolled, and 37 developed overt DIC within the following 5 days. Most patients demonstrated hemostatic abnormalities at baseline with 98.7% TAT, 97.4% FDP and 88.3% PC. Most hemostatic biomarkers at baseline were significantly associated with subsequent development of overt DIC. Notably, TAT, PAI-1 and PC discriminated well between patients with and without developing overt DIC (area under the receiver operating characteristic curve (AUROC), 0.77 (95% confidence interval, 0.64 to 0.86); 0.87 (0.78 to 0.92); 0.85 (0.76 to 0.91), respectively), and using the three together, significantly improved the AUROC up to 0.95 (vs. TAT, PAI-1, and PC). Among the significant diagnostic markers for overt DIC, TAT and PAI-1 were also good predictors of 28-day mortality (AUROC, 0.77 and 0.81, respectively).

Conclusions

Severe coagulation and fibrinolytic abnormalities on ICU admission were associated with subsequent development of overt DIC. A single measurement of TAT, PAI-1, and PC activity could identify patients with ongoing severe coagulopathy, early in the course of sepsis.

The role of protein C in sepsis

During the past 15 years, several anti-inflammatory treatments have failed to reduce mortality in patients with severe sepsis. However, recent evidence indicates that coagulation abnormalities in sepsis may play a major role in the pathogenesis of multiple organ failure and the high mortality rate in patients with severe sepsis. Interestingly, blockade of the coagulant pathway can inhibit both procoagulant and proinflammatory pathways in sepsis. Protein C, a natural anticoagulant, interrupts several of the pathophysiologic pathways in sepsis. Acquired protein C deficiency is present in the majority of septic patients and is associated with unfavorable outcomes. Protein C replacement therapy was effective in preclinical animal models of sepsis in reducing end-organ damage and mortality. Recent clinical trials of protein C replacement in human meningococcemia resulted in a markedly decreased morbidity and mortality. And, most importantly, in a recently completed large, randomized trial of activated protein C treatment in severe sepsis, mortality was reduced from 30.8% in the placebo group to 24.7% in the treatment group at 28 days. Thus, there is new evidence that mortality can be reduced among patients with severe sepsis through the use of a new therapy that inhibits the procoagulant and the inflammatory cascades.

Endogenous α2-antiplasmin is protective during severe gram-negative sepsis (melioidosis)

RATIONALE

α2-Antiplasmin (A2AP) is a major inhibitor of fibrinolysis by virtue of its capacity to inhibit plasmin. Although the fibrinolytic system is strongly affected by infection, the functional role of A2AP in the host response to sepsis is unknown.

OBJECTIVES

To study the role of A2AP in melioidosis, a common form of community-acquired sepsis in Southeast Asia and Northern Australia caused by the gram-negative bacterium Burkholderia pseudomallei.

METHODS

In a single-center observational study A2AP was measured in patients with culture-proven septic melioidosis. Wild-type and A2AP-deficient (A2AP(-/-)) mice were intranasally infected with B. pseudomallei to induce severe pneumosepsis (melioidosis). Parameters of inflammation and coagulation were measured, and survival studies were performed.

MEASUREMENTS AND MAIN RESULTS

Patients with melioidosis showed elevated A2AP plasma levels. Likewise, A2AP levels in plasma and lung homogenates were elevated in mice infected with B. pseudomallei. A2AP-deficient (A2AP(-/-)) mice had a strongly disturbed host response during experimental melioidosis as reflected by enhanced bacterial growth at the primary site of infection accompanied by increased dissemination to distant organs. In addition, A2AP(-/-) mice showed more severe lung pathology and injury together with an increased accumulation of neutrophils and higher cytokine levels in lung tissue. A2AP deficiency further was associated with exaggerated systemic inflammation and coagulation, increased distant organ injury, and enhanced lethality.

CONCLUSIONS

This study is the first to identify A2AP as a protective mediator during gram-negative (pneumo)sepsis by limiting bacterial growth, inflammation, tissue injury, and coagulation.

Biomarkers of endothelial cell activation in early sepsis

PURPOSE

The objective of this study was to investigate the association of endothelial-related markers with organ dysfunction and in-hospital mortality to validate our earlier findings in a multicenter study. We hypothesize that (i) endothelial biomarkers will be associated with organ dysfunction and mortality in sepsis and that (ii) soluble fms-like tyrosine kinase 1 (sFlt-1) holds promise as a novel prognostic marker in sepsis.

METHODS

This was a prospective, multicenter, observational study of a convenience sample of emergency department (ED) patients with a suspected infection presenting to one of four urban, academic medical center EDs between January 2009 and January 2010. We collected plasma while the patients were in the ED and subsequently assayed endothelial-related biomarkers, namely, sFlt-1, soluble E-selectin, soluble intercellular adhesion molecule 1, soluble vascular cell adhesion molecule 1, and plasminogen activator inhibitor 1 (PAI-1). Outcomes were organ dysfunction and in-hospital mortality.

RESULTS

We enrolled a total of 166 patients: 63 with sepsis (38%), 61 with severe sepsis (37%), and 42 with septic shock (25%). All endothelial biomarkers were significantly associated with sepsis severity, P < 0.002. We found a significant intercorrelation between all biomarkers, strongest between sFlt-1 and PAI-1 (r = 0.61, P < 0.001) and PAI-1 and soluble E-selectin and soluble intercellular adhesion molecule 1 (r = 0.49, P < 0.001). Among the endothelial biomarkers, sFlt-1 had the strongest association with Sequential Organ Failure Assessment score (r = 0.58, P < 0.001). Soluble fms-like tyrosine kinase 1 and PAI-1 had the highest area under the operating receiver characteristic curve for mortality of 0.87.

CONCLUSIONS

This multicenter validation study confirms that markers of endothelial activation are associated with sepsis severity, organ dysfunction, and mortality in sepsis. This supports the hypothesis that the endothelium plays a central role in the pathophysiology of sepsis and may serve as a more accurate prediction tool and a target for therapies aimed at ameliorating endothelial cell dysfunction. In addition, sFLT-1 holds promise as a novel sepsis severity biomarker.

Predictors of Disseminated Intravascular Coagulation in Patients with Septic Shock

Purpose. The goal of this study was to identify potential clinical predictors for the development of disseminated intravascular coagulation (DIC) in patients with septic shock. Material and Methods. We performed a retrospective analysis of a cohort of adult (>18 years of age) patients with septic shock admitted to a medical ICU in a tertiary care hospital from July 2005 until September 2007. A multivariate logistic regression model was used to determine the association of risk factors with overt DIC. Results. In this study, a total of 390 patients with septic shock were analyzed, of whom 66 (17%) developed overt DIC. Hospital mortality was significantly greater in patients who developed overt DIC (68% versus 38%, P<0.001). A delay in the timing of antibiotics was associated with an increased risk of the development of overt DIC (P<0.001). Patients on antiplatelet therapy prior to hospital admission and who that received adequate early goal-directed therapy (EGDT) were associated with a decreased risk of overt DIC (P<0.001). Conclusions. In our cohort of patients with septic shock, there was a risk reduction for overt DIC in patients on antiplatelet therapy and adequate EGDT, while there was an increased risk of DIC with antibiotic delay.

Late recognition and illness severity are determinants of early death in severe septic patients

OBJECTIVE

To identify the independent variables associated with death within 4 days after the first sepsis-induced organ dysfunction.

METHODS

In this prospective observational study, severe sepsis and septic shock patients were classified into 3 groups: Group 1, survivors; Group 2, late non-survivors; and Group 3, early non-survivors. Early death was defined as death occurring within 4 days after the first sepsis-induced organ dysfunction. Demographic, clinical and laboratory data were collected and submitted to univariate and multinomial analyses.

RESULTS

The study included 414 patients: 218 (52.7%) in Group 1, 165 (39.8%) in Group 2, and 31 (7.5%) in Group 3. A multinomial logistic regression analysis showed that age, Acute Physiology and Chronic Health Evaluation II score, Sepsis-related Organ Failure Assessment score after the first 24 hours, nosocomial infection, hepatic dysfunction, and the time elapsed between the onset of organ dysfunction and the sepsis diagnosis were associated with early mortality. In contrast, Black race and a source of infection other than the urinary tract were associated with late death. Among the non-survivors, early death was associated with Acute Physiology and Chronic Health Evaluation II score, chronic renal failure, hepatic dysfunction Sepsis-related Organ Failure Assessment score after 24 hours, and the duration of organ dysfunction.

CONCLUSION

Factors related to patients' intrinsic characteristics and disease severity as well as the promptness of sepsis recognition are associated with early death among severe septic patients.

Evaluation of hemostatic biomarker abnormalities that precede platelet count decline in critically ill patients with sepsis

PURPOSE

The hemostatic biomarkers for early diagnosis of sepsis-associated coagulopathy have not been identified. The purpose of this study was to evaluate hemostatic biomarker abnormalities preceding a decrease in platelet count, which is a surrogate indicator of overt coagulopathy in sepsis.

MATERIALS AND METHODS

Seventy-five septic patients with a platelet count more than 80×10(3)/μL were retrospectively analyzed. Hemostatic biomarkers at intensive care unit admission were compared between patients with and patients without a subsequent decrease in platelet count (≥30% within 5 days), and the ability of biomarkers to predict a decrease in platelet count was evaluated.

RESULTS

Forty-two patients (56.0%) developed a subsequent decrease in platelet count. Severity of illness, incidence of organ dysfunction, and 28-day mortality rate were higher in patients with a subsequent decrease in platelet count. There were significant differences between patients with and patients without a subsequent decrease in platelet count in prothrombin time-international normalized ratio, fibrinogen, thrombin-antithrombin complex, antithrombin, protein C (PC), plasminogen, and α2-plasmin inhibitor (α2-PI). Receiver operating characteristic curve analysis showed that PC (area under the curve, 0.869; 95% confidence interval, 0.699-0.951) and α2-PI (area under the curve, 0.885; 95% confidence interval, 0.714-0.959) were strong predictors of a subsequent decrease in platelet count.

CONCLUSIONS

Decreased PC and α2-PI activity preceded a decrease in platelet count in intensive care unit patients with sepsis.

A non-lethal traumatic/hemorrhagic insult strongly modulates the compartment-specific PAI-1 response in the subsequent polymicrobial sepsis

Introduction

Plasminogen activator inhibitor 1 (PAI-1) is a key factor in trauma- and sepsis-induced coagulopathy. We examined how trauma-hemorrhage (TH) modulates PAI-1 responses in subsequent cecal ligation and puncture (CLP)-induced sepsis, and the association of PAI-1 with septic outcomes.

Methods

Mice underwent TH and CLP 48 h later in three separate experiments. In experiment 1, mice were sacrificed pre- and post-CLP to characterize the trajectory of PAI-1 in plasma (protein) and tissues (mRNA). Post-CLP dynamics in TH-CLP (this study) and CLP-Only mice (prior study) were then compared for modulatory effects of TH. In experiment 2, to relate PAI-1 changes to outcome, mice underwent TH-CLP and were sampled daily and followed for 14 days to compare non-survivors (DEAD) and survivors (SUR). In experiment 3, plasma and tissue PAI-1 expression were compared between mice predicted to die (P-DIE) and to live (P-LIVE).

Results

In experiment 1, an early post-TH rise of circulating PAI-1 was contrasted by a delayed (post-TH) decrease of PAI-1 mRNA in organs. In the post-CLP phase, profiles of circulating PAI-1 were similar between TH-CLP and CLP-Only mice. Conversely, PAI-1 mRNA declined in the liver and heart of TH-CLP mice versus CLP-Only. In experiment 2, there were no DEAD/SUR differences in circulating PAI-1 prior to CLP. Post-CLP, circulating PAI-1 in DEAD was 2–4-fold higher than in SUR. PAI-1 increase heralded septic deaths up to 48 h prior but DEAD/SUR thrombomodulin (endothelial injury marker) levels were identical. In experiment 3, levels of circulating PAI-1 and its hepatic gene expression were higher in P-DIE versus P-LIVE mice and those increases closely correlated with liver dysfunction.

Conclusions

Trauma modulated septic PAI-1 responses in a compartment-specific fashion. Only post-CLP increases in circulating PAI-1 predicted septic outcomes. In posttraumatic sepsis, pre-lethal release of PAI-1 was mostly of hepatic origin and was independent of endothelial injury.

Activated protein C ameliorates Bacillus anthracis lethal toxin-induced lethal pathogenesis in rats

BACKGROUND

Lethal toxin (LT) is a major virulence factor of Bacillus anthracis. Sprague Dawley rats manifest pronounced lung edema and shock after LT treatments, resulting in high mortality. The heart failure that is induced by LT has been suggested to be a principal mechanism of lung edema and mortality in rodents. Since LT-induced death occurs more rapidly in rats than in mice, suggesting that other mechanisms in addition to the heart dysfunction may be contributed to the fast progression of LT-induced pathogenesis in rats. Coagulopathy may contribute to circulatory failure and lung injury. However, the effect of LT on coagulation-induced lung dysfunction is unclear.

METHODS

To investigate the involvement of coagulopathy in LT-mediated pathogenesis, the mortality, lung histology and coagulant levels of LT-treated rats were examined. The effects of activated protein C (aPC) on LT-mediated pathogenesis were also evaluated.

RESULTS

Fibrin depositions were detected in the lungs of LT-treated rats, indicating that coagulation was activated. Increased levels of plasma D-dimer and thrombomodulin, and the ameliorative effect of aPC further suggested that the activation of coagulation-fibrinolysis pathways plays a role in LT-mediated pathogenesis in rats. Reduced mortality was associated with decreased plasma levels of D-dimer and thrombomodulin following aPC treatments in rats with LT-mediated pathogenesis.

CONCLUSIONS

These findings suggest that the activation of coagulation in lung tissue contributes to mortality in LT-mediated pathogenesis in rats. In addition, anticoagulant aPC may help to develop a feasible therapeutic strategy.

A pilot study assessing the prognostic value of CK18 and nDNA biomarkers in severe sepsis patients

BACKGROUND AND OBJECTIVES

Severe sepsis and septic shock have posed significant treatment challenges for many years. Recently, a number of circulating apoptosis biomarkers have emerged, such as full-length and caspase-cleaved cytokeratin 18 (CK18) and nucleosomal DNA (nDNA), that may be predictive of likely outcome. This non-interventional study aimed to assess the ability of enzyme-linked immunosorbent assays (ELISAs) for these biomarkers to provide clinically useful information to guide the management of sepsis.

METHODS

This study was conducted in patients admitted to the intensive care unit with severe sepsis at five US centres. Blood samples for assessment of plasma levels of full-length CK18 (measured by the M65® ELISA) and caspase-cleaved CK18 (measured by the M30-Apoptosense® ELISA) and nDNA (measured by ELISA) were collected from patients within 2 hours of consent (baseline) and on days 2, 4 and 8. Blood samples from 17 healthy volunteers acted as controls. Levels of each biomarker were presented descriptively.

RESULTS

A total of 22 patients (mean age 60 [range, 24-83] years; 50% male) were included in the study. The mean APACHE II score was 24.4 (range 7-50). One-third of patients had three organ system failures and over one-half had septic shock. Three patients died during the study. Full-length and caspase-cleaved CK18 levels decreased within 48 hours following initiation of treatment of sepsis in patients who survived, whereas increases were observed in the same timeframe in patients who died within 28 days of admission. Baseline nDNA and total soluble CK18 levels (caspase-cleaved and total intact) were significantly (p ≤ 0.05) higher in patients who required renal support than those who did not.

CONCLUSIONS

Despite the small numbers of subjects assessed in the current study, these results confirm that measurement of apoptosis biomarkers may help to provide clinically useful information to manage sepsis and expedite development of novel therapeutics. However, further investigations to fully assess their prognostic value are required.

Several Cytokines and Protein C Levels with the Apache II Scoring System for Evaluation of Patients with Sepsis

OBJECTIVE

We investigated whether determination IL-6, IL-8, IL-1beta and TNF-alpha at baseline, total protein C (PC) levels at time of admission and 48 hours after initiation could complement the Acute Physiology and Chronic Health Evaluation (APACHE) II scoring system to identify patients with sepsis, severe sepsis or septic shock for clinical outcome.

MATERIAL AND METHODS

The study was carried out prospectively. 60 consecutive patients with sepsis, severe sepsis or septic shock were included. Blood samples were obtained at baseline and 48 hours after initiation. Cytokines and PC levels in plasma were measured with an enzyme-linked immunoabsorbent assay (ELISA). APACHE II score was calculated on admission.

RESULTS

Baseline IL-6 levels and PC levels 48 hours after initiation were predictive of increased mortality (p=0.016, p=0.044 respectively). Baseline IL-6, IL-8 and TNF-alpha baseline levels correlate with the severity of physiologic insult, as determined by the APACHE II score. However, our multiple logistic regression analysis of these did not reveal any predictive value in combination with the APACHE II score.

CONCLUSION

Determination of baseline IL-6 and PC 48 hours after initiation were of predictive value for prognostic evaluation of septic patients, but did not significantly increase predictive power of the APACHE scoring system to identify patients with sepsis for fatal clinical outcome.