Increased circulating thrombomodulin in children with septic shock

Hemostasis Proteins in Invasive Meningococcal and Nonmeningococcal Infections: A Prospective Multicenter Study

OBJECTIVES

We aimed to describe the variation of hemostasis proteins in children with bacterial infections due to different pathogens ( Neisseria meningitidis, Streptococcus pneumoniae, Staphylococcus aureus , and group A streptococcus [GAS]) and to study hemostasis proteins in relation to mortality.

DESIGN

Preplanned analysis in prospective cohort study.

SETTING

Hospitals in five European countries (Austria, The Netherlands, Spain, Switzerland, and the United Kingdom).

PATIENTS

Admitted children (2012-2016) with community-acquired infections due to meningococci ( n = 83), pneumococci ( n = 64), S. aureus (n = 50), and GAS ( n = 44) with available serum samples collected less than 48 hours after admission.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Fibronectin, plasminogen activator inhibitor type 1 (PAI-1), thrombomodulin, and a disintegrin and metalloproteinase with a thrombospondin type 1 motif, member 13 (ADAMTS-13) were measured in serum in 2019-2020. Additionally, von Willebrand factor, protein C, protein S, and factor IX were measured in citrate plasma available from a subset of patients. Outcome measures included in-hospital mortality and disease severity (need for ventilation/inotropes, Pediatric Index of Mortality score).Of 241 children, 21 (8.7%) died and 177 (73.5%) were admitted to PICU. Mortality rate was similar for the pathogen groups. Levels of fibronectin and thrombomodulin differed for the different pathogens ( p < 0.05). Fibronectin levels were lower in GAS infections than in S. pneumoniae and S. aureus infections but did not differ from meningococcal infections. Thrombomodulin levels in meningococcal infections were higher than in S. aureus and pneumococcal infections. Overall, the area under the curve for mortality was 0.81 (95% CI, 0.70-0.92) for thrombomodulin and 0.78 (95% CI, 0.69-0.88) for ADAMTS-13. The association of each hemostasis protein did not vary across pathogens for any of the outcome measures.

CONCLUSIONS

Hemostatic disturbances in childhood bacterial infections are not limited to meningococcal sepsis but occur with a comparable severity across nonmeningococcal infections. High thrombomodulin and high ADAMTS-13 had good discriminative ability for mortality. Our results emphasize the importance of hemostatic disturbances in meningococcal and nonmeningococcal pediatric bacterial infections.

Value of Thrombomodulin as a Marker for Sepsis in Critically Ill Children

OBJECTIVE

Pediatric sepsis is altered organ function in critically ill children and a main etiology of mortality for children. Therefore, the authors aimed to assess the role of serum thrombomodulin as valuable biomarker in the diagnosis and prognosis of sepsis in acutely ill pediatrics in the intensive unit.

METHODS

This prospective clinical study conducted on 140 acutely ill patients admitted to the Pediatric Intensive Care Unit (PICU) of Menoufia University Hospital and 50 apparently healthy controls from October 2018 through September 2019. All included children were subjected to clinical examination and the Pediatric Risk of Mortality (PRISM) and Pediatric Index of Mortality II (PIM II) scores were calculated. Serum thrombomodulin was measured for both patients and the control group upon admission. The children were followed for a period of 30 d.

RESULTS

Serum thrombomodulin level was increased among all the patients and those with systemic inflammatory response syndrome (SIRS), sepsis and severe sepsis compared with controls (p < 0.001). Furthermore, serum thrombomodulin was higher in patients who died than who survived (p = 0.005). Thrombomodulin had area under Receiver Operating Characteristic Curve (AUC) =0.915 for predicting sepsis, whereas C-reactive protein had AUC = 0.789. According to the prognosis, thrombomodulin had AUC = 0.711 for predicting mortality whereas PRISM and PIM scores had AUC = (0.918, 0.960) respectively.

CONCLUSIONS

Serum thrombomodulin is a promising marker for pediatric sepsis. The data showed that serum thrombomodulin had a valuable role in diagnosis of sepsis early in critically ill pediatrics.

Systemic Endothelial Activation Is Associated With Early Acute Respiratory Distress Syndrome in Children With Extrapulmonary Sepsis

OBJECTIVES

Systemic endothelial activation may contribute to sepsis-associated organ injury, including acute respiratory distress syndrome. We hypothesized that children with extrapulmonary sepsis with versus without acute respiratory distress syndrome would have plasma biomarkers indicative of increased endothelial activation and that persistent biomarker changes would be associated with poor outcome.

DESIGN

Observational cohort.

SETTING

Academic PICU.

PATIENTS

Patients less than 18 years old with sepsis from extrapulmonary infection with (n = 46) or without (n = 54) acute respiratory distress syndrome and noninfected controls (n = 19).

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Endothelial (angiopoietin-1, angiopoietin-2, tyrosine kinase with immunoglobulin-like loop epidermal growth factor homology domain 2, vascular endothelial growth factor, soluble fms-like tyrosine kinase, von Willebrand factor, E-selectin, intercellular adhesion molecule, vascular cell adhesion molecule, thrombomodulin) and inflammatory biomarkers (C-reactive protein, interleukin-6, and interleukin-8) were measured from peripheral plasma collected within 3 days (time 1) of sepsis recognition and at 3-6 days (time 2) and 7-14 days (time 3). Time 1 biomarkers and longitudinal measurements were compared for sepsis patients with versus without acute respiratory distress syndrome and in relation to complicated course, defined as greater than or equal to two organ dysfunctions at day 7 or death by day 28. Angiopoietin-2, angiopoietin-2/angiopoietin-1 ratio, tyrosine kinase with immunoglobulin-like loop epidermal growth factor homology domain 2, vascular endothelial growth factor, von Willebrand factor, E-selectin, intercellular adhesion molecule, vascular cell adhesion molecule, thrombomodulin, endocan, C-reactive protein, interleukin-6, and interleukin-8 were different between sepsis and noninfected control patients at time 1. Among patients with sepsis, those with acute respiratory distress syndrome had higher angiopoietin-2/angiopoietin-1 ratio, vascular endothelial growth factor, vascular cell adhesion molecule, thrombomodulin, endocan, interleukin-6, and interleukin-8 than those without acute respiratory distress syndrome (all p < 0.003). Angiopoietin-2 and angiopoietin-2/angiopoietin-1 ratio remained higher in sepsis with versus without acute respiratory distress syndrome after multivariable analyses. Time 1 measures of angiopoietin-2, angiopoietin-2/-1 ratio, von Willebrand factor, and endocan were indicative of complicated course in all sepsis patients (all area under the receiver operating curve ≥ 0.80). In sepsis without acute respiratory distress syndrome, soluble fms-like tyrosine kinase decreased more quickly and von Willebrand factor and thrombomodulin decreased more slowly in those with complicated course.

CONCLUSIONS

Children with extrapulmonary sepsis with acute respiratory distress syndrome had plasma biomarkers indicative of greater systemic endothelial activation than those without acute respiratory distress syndrome. Several endothelial biomarkers measured near sepsis recognition were associated with complicated course, whereas longitudinal biomarker changes yielded prognostic information only in those without sepsis-associated acute respiratory distress syndrome.

Distinct Biomarker Profiles Distinguish Malawian Children with Malarial and Non-malarial Sepsis

Presently, it is difficult to accurately diagnose sepsis, a common cause of childhood death in sub-Saharan Africa, in malaria-endemic areas, given the clinical and pathophysiological overlap between malarial and non-malarial sepsis. Host biomarkers can distinguish sepsis from uncomplicated fever, but are often abnormal in malaria in the absence of sepsis. To identify biomarkers that predict sepsis in a malaria-endemic setting, we retrospectively analyzed data and sera from a case-control study of febrile Malawian children (aged 6-60 months) with and without malaria who presented to a community health center in Blantyre (January-August 2016). We characterized biomarkers for 29 children with uncomplicated malaria without sepsis, 25 without malaria or sepsis, 17 with malaria and sepsis, and 16 without malaria but with sepsis. Sepsis was defined using systemic inflammatory response criteria; biomarkers (interleukin-6 [IL-6], tumor necrosis factor receptor-1, interleukin-1 β [IL-1β], interleukin-10 [IL-10], von Willebrand factor antigen-2, intercellular adhesion molecule-1, and angiopoietin-2 [Ang-2]) were measured with multiplex magnetic bead assays. IL-6, IL-1β, and IL-10 were elevated, and Ang-2 was decreased in children with malaria compared with non-malarial fever. Children with non-malarial sepsis had greatly increased IL-1β compared with the other subgroups. IL-1β best predicted sepsis, with an area under the receiver operating characteristic (AUROC) of 0.71 (95% CI: 0.57-0.85); a combined biomarker-clinical characteristics model improved prediction (AUROC of 0.77, 95% CI: 0.67-0.85). We identified a distinct biomarker profile for non-malarial sepsis and developed a sepsis prediction model. Additional clinical and biological data are necessary to further explore sepsis pathophysiology in malaria-endemic regions.

Global Case-Fatality Rates in Pediatric Severe Sepsis and Septic Shock: A Systematic Review and Meta-analysis

IMPORTANCE

The global patterns and distribution of case-fatality rates (CFRs) in pediatric severe sepsis and septic shock remain poorly described.

OBJECTIVE

We performed a systematic review and meta-analysis of studies of children with severe sepsis and septic shock to elucidate the patterns of CFRs in developing and developed countries over time. We also described factors associated with CFRs.

DATA SOURCES

We searched PubMed, Web of Science, Excerpta Medica database, Cumulative Index of Nursing and Allied Health Literature (CINAHL), and Cochrane Central systematically for randomized clinical trials and prospective observational studies from earliest publication until January 2017, using the keywords "pediatric," "sepsis," "septic shock," and "mortality."

STUDY SELECTION

Studies involving children with severe sepsis and septic shock that reported CFRs were included. Retrospective studies and studies including only neonates were excluded.

DATA EXTRACTION AND SYNTHESIS

We conducted our systematic review and meta-analysis in close accordance to Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Pooled case-fatality estimates were obtained using random-effects meta-analysis. The associations of study period, study design, sepsis severity, age, and continents in which studies occurred were assessed with meta-regression.

MAIN OUTCOMES AND MEASURES

Meta-analyses to provide pooled estimates of CFR of pediatric severe sepsis and septic shock over time.

RESULTS

Ninety-four studies that included 7561 patients were included. Pooled CFRs were higher in developing countries (31.7% [95% CI, 27.3%-36.4%]) than in developed countries (19.3% [95% CI, 16.4%-22.7%]; P < .001). Meta-analysis of CFRs also showed significant heterogeneity across studies. Continents that include mainly developing countries reported higher CFRs (adjusted odds ratios: Africa, 7.89 [95% CI, 6.02-10.32]; P < .001; Asia, 3.81 [95% CI, 3.60-4.03]; P < .001; South America, 2.91 [95% CI, 2.71-3.12]; P < .001) than North America. Septic shock was associated with higher CFRs than severe sepsis (adjusted odds ratios, 1.47 [95% CI, 1.41-1.54]). Younger age was also a risk factor (adjusted odds ratio, 0.95 [95% CI, 0.94-0.96] per year of increase in age). Earlier study eras were associated with higher CFRs (adjusted odds ratios for 1991-2000, 1.24 [95% CI, 1.13-1.37]; P < .001) compared with 2011 to 2016. Time-trend analysis showed higher CFRs over time in developing countries than developed countries.

CONCLUSIONS AND RELEVANCE

Despite the declining trend of pediatric severe sepsis and septic shock CFRs, the disparity between developing and developed countries persists. Further characterizations of vulnerable populations and collaborations between developed and developing countries are warranted to reduce the burden of pediatric sepsis globally.

Effect of Coupled Plasma Filtration Adsorption on Endothelial Cell Function in Patients with Multiple Organ Dysfunction Syndrome

Objective

The purpose of our study was to investigate the effect of coupled plasma filtration adsorption (CPFA) on endothelial cell (EC) function in patients with multiple organ dysfunction syndrome (MODS).

Methods

Besides routine therapy, the 24 MODS patients underwent both CPFA and high volume hemofiltration (HVHF), scheduled randomly at intervals of 12 hours. Patient serum from 0, 5, and 10 hours of therapy was collected to measure soluble E-selectin (sE-selectin) and soluble thrombomodulin (sTM) by the ELISA method. Human umbilical vein endothelial cells (HUVEC) were incubated for 24 hours with the patient serum and the supernatant liquid was gathered to detect sTM and sE-selectin. The proliferation function of the ECs was detected by methyl thiazolyl tetrazolium (MTT) method.

Results

1. The serum levels of sE-selectin and sTM were significantly higher in MODS patients than in controls; serum sE-selectin and sTM decreased remarkably after a single circulation in CPFA (p<0. 05) but not in HVHF (p>0. 05); the level of sE-selectin and sTM in systemic circulation had no change during CPFA or HVHF (p>0.05); 2. sTM in supernatant liquid incubated with serum from 5 hours of CPFA and 10 hours of HVHF decreased remarkably (p<0.05), while sE-selectin decreased significantly (p<0. 05) from 10 hours of CPFA, but there was no change from 5 hours and 10 hours of HVHF (p>0. 05); 3. when incubated with serum taken from the device pre- or post-CPFA, the optical density (OD) value of the latter was higher. The OD value increased gradually when incubated with serum from 0, 5, and 10 hours of CPFA (p<0.05), but changed little from HVHF.

Conclusions

CPFA can eliminate sE-selectin and sTM and improve the secretion function of ECs. CPFA was somewhat better and earlier than HVHF, while to a certain degree it can weaken the inhibitory effect of serum on the proliferation function of ECs.

Increased serum thrombomodulin level is associated with disease severity and mortality in pediatric sepsis

Background

Endothelial dysfunction plays an important role in the pathophysiology of sepsis. As previously reported, the serum thrombomodulin is elevated in diseases associated with endothelial injury.

Objective

The aim of this study was to investigate the association of serum thrombomodulin level in different pediatric sepsis syndromes and evaluate the relationship with disease severity and mortality.

Methods

We prospectively collected cases of sepsis treated in a pediatric intensive care unit from June 2012 to July 2015 at Chang Gung Children’s Hospital in Taoyuan, Taiwan. Clinical characteristics and serum thrombomodulin levels were analyzed.

Results

Increased serum thrombomodulin levels on days 1 and 3 of the diagnosis of sepsis were found in different pediatric sepsis syndromes. Patients with septic shock had significantly increased serum thrombomodulin levels on days 1 and 3 [day 1: median, 6.9 mU/ml (interquartile range (IQR): 5.8–12.8) and day 3: median, 5.8 mU/ml (IQR: 4.6–10.8)] compared to healthy controls [median, 3.4 mU/ml (IQR: 2.3–4.2)] (p = <0.001 and 0.001, respectively) and those with sepsis [day 1: median, 2.9 mU/ml (IQR: 1.8–4.7) and day 3: median, 3 mU/ml (IQR: 1.5–3.5)] and severe sepsis [day 1: median, 3.3 mU/ml (IQR: 1.3–8.6) and day 3: median, 4.4 mU/ml (IQR: 0.5–6)] (p = <0.001 and 0.001, respectively). There was also a significant positive correlation between serum thrombomodulin level on day 1 and day 1 PRISM-II, PELOD, P-MOD and DIC scores. The patients who died had significantly higher serum thrombomodulin levels on days 1 and 3 [day 1: median, 9.9 mU/ml (IQR: 6.2–15.6) and day 3: median, 10.4 mU/ml (IQR: 9.2–11.7)] than the survivors [day 1; median, 4.4 mU/ml (IQR: 2.2–7.5) and day 3: [median, 3.5 mU/ml (IQR: 1.6–5.7)] (p = 0.046 and 0.012, respectively).

Conclusion

Increased serum thrombomodulin levels were found in different pediatric sepsis syndromes and correlated with disease severity and mortality.

Elevated soluble thrombomodulin is associated with organ failure and mortality in children with acute respiratory distress syndrome (ARDS): a prospective observational cohort study

INTRODUCTION

The significance of endothelial injury in children with the acute respiratory distress syndrome (ARDS) has not been well studied. Plasma levels of soluble thrombomodulin (sTM), an endothelial surface protein involved in coagulation, have been associated with endothelial injury. We hypothesized that elevated plasma sTM would correlate with mortality and organ failure in children with ARDS.

METHODS

We conducted a multicenter prospective observational study of pediatric patients with ARDS between 2008 and 2014. sTM was measured in plasma collected less than 24 hours from ARDS diagnosis. Outcomes were intensive care unit mortality and organ dysfunction by pediatric logistic organ dysfunction scores. Logistic regression was used to adjust for clinically relevant covariates.

RESULTS

Plasma sTM was higher in patients with indirect lung injury compared to direct lung injury (100 ng/mL vs. 86 ng/mL, p = 0.02). Increased sTM levels were correlated with more organ dysfunction in the entire study population (Spearman's rho = 0.37, p < 0.01). Overall mortality was 16%. sTM levels were associated with increased mortality in patients with indirect lung injury (OR 2.7 per log(sTM), p = 0.02). These relationships were independent of age, oxygenation defect, or presence of acute kidney injury.

CONCLUSION

Elevated plasma sTM levels are associated with organ dysfunction in children with ARDS and with higher mortality in children with indirect lung injury. These findings highlight the importance of endothelial injury in children with ARDS and may guide the development of future therapies targeted toward endothelial stabilization, repair, or functional replacement in this population.

The role of soluble thrombomodulin in the risk stratification and prognosis evaluation of septic patients in the emergency department

INTRODUCTION

Soluble thrombomodulin (sTM) is a sensitive marker of endothelial damage. In this study we investigated the role of sTM in the evaluation of the severity and prognosis of septic patients in the emergency department (ED).

MATERIALS AND METHODS

A prospective, observational cohort study was performed in the ED of an urban, university hospital. Patients who had suspected infection with two or more criteria of systemic inflammatory response syndrome were consecutively enrolled. sTM, D-Dimer and procalcitonin levels were measured on enrollment, and the Mortality in Emergency Department Sepsis (MEDS) score was calculated. A 30-day follow-up was performed for all patients.

RESULTS

A total of 372 patients with sepsis, 210 patients with severe sepsis and 98 patients with septic shock were enrolled in this study. According to the disease severity, patients were divided into sepsis subgroup and severe sepsis subgroup (including septic shock). In addition, patients were divided into survivors subgroup and non-survivors subgroup according to the 30-day mortality. Plasma sTM levels in patients with severe sepsis were higher than those with sepsis (P<0.001). Compared with survivors, non-survivors has higher plasma sTM levels (P<0.001). Multivariate logistic regression analysis showed that sTM was an independent predictor of severe sepsis (odds ratio 1.11) and 30-day mortality (odds ratio 1.059). Receiver operating characteristic curve analysis showed that sTM was a useful parameter in prediction of severe sepsis (0.859) and 30-day mortality (0.78). Compared with the MEDS score alone, combination of sTM and the MEDS score can improve the accuracy in prediction of severe sepsis and 30-day mortality.

CONCLUSIONS

sTM is a valuable biomarker in the risk stratification and prognosis evaluation of ED sepsis. Furthermore, sTM can enhance the ability of the MEDS score in prediction of severe sepsis and 30-day mortality.

Biomarkers of endothelial activation/dysfunction in infectious diseases

Endothelial dysfunction contributes to the pathogenesis of a variety of potentially serious infectious diseases and syndromes, including sepsis and septic shock, hemolytic-uremic syndrome, severe malaria, and dengue hemorrhagic fever. Because endothelial activation often precedes overt endothelial dysfunction, biomarkers of the activated endothelium in serum and/or plasma may be detectable before classically recognized markers of disease, and therefore, may be clinically useful as biomarkers of disease severity or prognosis in systemic infectious diseases. In this review, the current status of mediators of endothelial cell function (angiopoietins-1 and -2), components of the coagulation pathway (von Willebrand Factor, ADAMTS13, and thrombomodulin), soluble cell-surface adhesion molecules (soluble E-selectin, sICAM-1, and sVCAM-1), and regulators of vascular tone and permeability (VEGF and sFlt-1) as biomarkers in severe infectious diseases is discussed in the context of sepsis, E. coli O157:H7 infection, malaria, and dengue virus infection.

Therapeutic modulation of coagulation and fibrinolysis in acute lung injury and the acute respiratory distress syndrome

Acute respiratory distress syndrome (ARDS) and acute lung injury (ALI) are characterized by excessive intraalveolar fibrin deposition, driven, at least in part by inflammation. The imbalance between activation of coagulation and inhibition of fibrinolysis in patients with ALI/ARDS favors fibrin formation and appears to occur both systemically and in the lung and airspace. Tissue factor (TF), a key mediator of the activation of coagulation in the lung, has been implicated in the pathogenesis of ALI/ARDS. As such, there have been numerous investigations modulating TF activity in a variety of experimental systems in order to develop new therapeutic strategies for ALI/ARDS. This review will summarize current understanding of the role of TF and other proteins of the coagulation cascade as well the fibrinolysis pathway in the development of ALI/ARDS with an emphasis on the pathways that are potential therapeutic targets. These include the TF inhibitor pathway, the protein C pathway, antithrombin, heparin, and modulation of fibrinolysis through plasminogen activator- 1 (PAI-1) or plasminogen activators (PA). Although experimental studies show promising results, clinical trials to date have proven unsuccessful in improving patient outcomes. Modulation of coagulation and fibrinolysis has complex effects on both hemostasis and inflammatory pathways and further studies are needed to develop new treatment strategies for patients with ALI/ARDS.

Jack of all trades: pleiotropy and the application of chemically modified tetracycline-3 in sepsis and the acute respiratory distress syndrome (ARDS)

Sepsis is a disease process that has humbled the medical profession for centuries with its resistance to therapy, relentless mortality, and pathophysiologic complexity. Despite 30 years of aggressive, concerted, well-resourced efforts the biomedical community has been unable to reduce the mortality of sepsis from 30%, nor the mortality of septic shock from greater than 50%. In the last decade only one new drug for sepsis has been brought to the market, drotrecogin alfa-activated (Xigris™), and the success of this drug has been limited by patient safety issues. Clearly a new agent is desperately needed. The advent of recombinant human immune modulators held promise but the outcomes of clinical trials using biologics that target single immune mediators have been disappointing. The complex pathophysiology of the systemic inflammatory response syndrome (SIRS) is self-amplifying and redundant at multiple levels. In this review we argue that perhaps pharmacologic therapy for sepsis will only be successful if it addresses this pathophysiologic complexity; the drug would have to be pleiotropic, working on many components of the inflammatory cascade at once. In this context, therapy that targets any single inflammatory mediator will not adequately address the complexity of SIRS. We propose that chemically modified tetracycline-3, CMT-3 (or COL-3), a non-antimicrobial modified tetracycline with pleiotropic anti-inflammatory properties, is an excellent agent for the management of sepsis and its associated complication of the acute respiratory distress syndrome (ARDS). The purpose of this review is threefold: (1) to examine the shortcomings of current approaches to treatment of sepsis and ARDS in light of their pathophysiology, (2) to explore the application of COL-3 in ARDS and sepsis, and finally (3) to elucidate the mechanisms of COL-3 that may have potential therapeutic benefit in ARDS and sepsis.

Lectin-like domain of thrombomodulin binds to its specific ligand Lewis Y antigen and neutralizes lipopolysaccharide-induced inflammatory response

Thrombomodulin (TM), a widely expressing glycoprotein originally identified in vascular endothelium, is an important cofactor in the protein C anticoagulant system. TM appears to exhibit anti-inflammatory ability through both protein C-dependent and -independent pathways. We presently have demonstrated that recombinant N-terminal lectinlike domain of TM (rTMD1) functions as a protective agent against sepsis caused by Gram-negative bacterial infections. rTMD1 caused agglutination of Escherichia coli and Klebsiella pneumoniae and enhanced the macrophage phagocytosis of these Gram-negative bacteria. Moreover, rTMD1 bound to the Klebsiella pneumoniae and lipopolysaccharide (LPS) by specifically interacting with Lewis Y antigen. rTMD1 inhibited LPS-induced inflammatory mediator production via interference with CD14 and LPS binding. Furthermore, rTMD1 modulated LPS-induced mitogen-activated protein kinase and nuclear factor-kappaB signaling pathway activations and inducible nitric oxide synthase expression in macrophages. Administration of rTMD1 protected the host by suppressing inflammatory responses induced by LPS and Gram-negative bacteria, and enhanced LPS and bacterial clearance in sepsis. Thus, rTMD1 can be used to defend against bacterial infection and inhibit LPS-induced inflammatory responses, suggesting that rTMD1 may be valuable in the treatment of severe inflammation in sepsis, especially in Gram-negative bacterial infections.

Detection and quantification of thrombomodulin in human semen

The presence of fibrin degradation products, thrombin-like enzyme, prothrombin fragments, thrombin-activatable fibrinolysis inhibitor, plasmin and other active components of blood coagulation and fibrinolysis in seminal plasma has been reported. In the present study we investigate the presence of thrombomodulin in human semen. Using an Imubind thrombomodulin enzyme-linked immunosorbent assay (American Diagnostica Inc., Stamford, Connecticut, USA), seminal thrombomodulin levels were measured in 47 semen specimens obtained from subfertile individuals, normally fertile individuals, semen donors as well as vasectomized individuals, and in a further group defined by normality in several parameters derived from the World Health Organization fertility criteria. Conventional semen parameters were analysed in all semen samples. Thrombomodulin is quantifiable in human semen at a concentration lower than that normally found in citrated blood plasma samples. Slightly higher levels were seen for fertile stratifications compared with infertile individuals but without significant difference, given the numbers accrued. A vasectomized group showed the lowest value. In conclusion, our results establish the presence of thrombomodulin in human semen and suggest its production both upstream and downstream from the level of a vasectomy lesion.

Plasma level of thrombomodulin is an early indication of pancreatic necrosis in patients with acute pancreatitis

BACKGROUND

The potential to predict pancreatic necrosis within the first 48 h by using plasma soluble thrombomodulin (sTM) in 104 patients with acute pancreatitis (AP) was analyzed in a prospective 5-year investigation performed at a single institution.

METHODS

According to Balthazar CT grade, pancreatitis was classified as no necrosis in 72 patients, one-third necrotic in 18 patients, one-half necrotic in 10 patients and more than one-half necrotic in 4 patients. Blood was collected at the first 48 hours after the onset of pain and analyzed for sTM.

RESULTS

In the healthy volunteers, plasma levels of TM were 16.49+/-5.24 microg/L. By comparison, the mean plasma levels of TM in each group of pancreatitis patients were as follows: CT grade A group, 34.21+/-10.73 microg/L; CT grade B group, 36.18+/-12.50 microg/L; CT grade C group, 49.39+/-18.38 microg/L; CT grade D group, 114.46+/-39.44 microg/L; CT grade E group, 100.22+/-15.97 microg/L (p<0.01). And for the patients, the Pearson correlation coefficient between the CT grade and TM values was 0.784 (p<0.01). No necrosis group, 39.22+/-13.75 microg/L; one-third necrotic group, 71.44+/-18.02 microg/L; one-half necrotic group, 123.50+/-28.57 microg/L; more than one-half necrotic group, 129.00+/-33.28 microg/L (p<0.01); And for the patients, the Pearson correlation coefficient between the degree of necrosis and TM values was 0.888 (p<0.01). ROC analysis indicated the area under the ROC curve (AUC +/- SE) for sTM was 0.949+/-0.020, clearly supportive of the high accuracy of this index in predicting the necrosis of AP.

CONCLUSION

Plasma soluble thrombomodulin (sTM) is a potential marker to predict pancreatic necrosis within the first 48 h, and further investigation in a multicentre study is necessary.

Novel role of the human alveolar epithelium in regulating intra-alveolar coagulation

Intra-alveolar fibrin deposition is a common response to localized and diffuse lung infection and acute lung injury (ALI). We hypothesized that the alveolar epithelium modulates intra-alveolar fibrin deposition through activation of protein C. Our objectives [corrected] were to determine whether components of the protein C activation pathway are present in the alveolar compartment in ALI and whether alveolar epithelium is a potential source. In patients with ALI, pulmonary edema fluid levels of endothelial protein C receptor (EPCR) were higher than plasma, suggesting a source in the lung. To determine whether alveolar epithelial cells are a potential source, protein C activation by A549, small airway epithelial, and primary human alveolar epithelial type II cells was measured. All three cell types express thrombomodulin (TM) and EPCR, and activate protein C on the cell surface. Activation of protein C was inhibited by cytomix (TNF-alpha, IL-1beta, and IFN-gamma). Release of EPCR and TM into the conditioned medium was inhibited by the metalloproteinase inhibitors tumor necrosis factor protease inhibitor (TAPI) and GM6001, indicating that the shedding of EPCR and TM from the alveolar epithelium is mediated by a metalloproteinase. These findings provide new evidence that the alveolar epithelium can modulate the protein C pathway and thus could be an important determinant of alveolar fibrin deposition. Local fibrin deposition may be a fundamental mechanism for the lung to localize and confine injury, thus limiting the risk of dissemination of injury or infection to the systemic circulation.

Epidural Analgesia Prevents Endotoxin-Induced Gut Mucosal Injury in Rabbits

In the present study, we evaluated the effect of epidural analgesia on the alterations of gut barrier function elicited by endotoxin in rabbits. After the placement of an epidural catheter, 28 male rabbits were randomized into either 0.5% lidocaine (group E) or saline (group C) group. The solutions (0.4 mL/kg) were epidurally injected, followed by continuous infusion (0.1 mL . kg(-1) . h(-1)) throughout the study period. Under a continuous infusion of lipopolysaccharide (15 microg . kg(-1) . h(-1)), mean arterial blood pressure, intramucosal pH, and plasma thrombomodulin concentrations were measured. At 4 h, mean arterial blood pressure was lower (P < 0.05), intramucosal pH was higher (P < 0.01), and the progression of hemodilution more profound (P < 0.05) in group E versus group C, whereas plasma thrombomodulin levels were increased to a similar extent between the groups. With less wet-to-dry weight ratio of ileum, histopathological injury scores of gut mucosa were significantly less in group E versus group C (P < 0.01). In a separate series of experiments (n = 10 each group), mucosal permeability in group E was significantly less compared with group C (P < 0.05). Collectively, these studies showed that despite a significant decrease of perfusion pressure and arterial oxygen content, epidural analgesia minimized endotoxin-induced functional and structural injury of gut mucosa possibly through endothelium-independent mechanisms.

Pediatric sepsis definitions: past, present, and future

OBJECTIVE

To review the past, present, and future definitions of sepsis and the systemic inflammatory response syndrome in children.

METHODS

Review of the literature.

RESULTS

The history and development of the adult-derived sepsis syndrome and its application to pediatric-specific sepsis definitions is provided. Initially, only adult definitions were applied to pediatric studies. Recently, pediatric-specific definitions have been published. The pediatric consensus conference-derived definitions for systemic inflammatory response syndrome, sepsis, severe sepsis, and septic shock are summarized, and their limitations are discussed.

CONCLUSIONS

The potential value and inconsistencies of the current pediatric-specific sepsis definitions are discussed. Future direction of the definitions and their applications are presented.

Definitions of bloodstream infection in the newborn

OBJECTIVE

To develop definitions of bloodstream infections in the newborn that would enable clinicians to identify infection early, so patients can be enrolled in clinical trials. The definitions should be useful for surveillance and epidemiologic purposes.

METHOD

Search of EMBASE, MEDLINE, and Cochrane Library using age and English language limited key words sepsis, septicemia, and shock. Extensive study of textbook of neonatology and discussions with experts in the field.

RESULTS

The search identified >2,000 references. The most appropriate were selected and reviewed. Definitions of bloodstream infection were developed after consultation with an international faculty.

CONCLUSION

Current definitions of neonatal infection (and associated categories) used by neonatal clinicians and researchers have been either adapted/modified from definitions developed for adults or generated by individuals to suit their local needs or the needs of a particular study. It is clear that definitions generated for adults are not applicable to children or to newborn infants. In addition, developing and using unique definitions to suit individual or local needs make comparisons of outcome data and result of studies very difficult. This article proposes a set of definitions that are based as much as possible on current evidence. These definitions may be applicable widely for daily management of an infant with an infection and for research and epidemiologic studies.

Extracellular hsp70 levels in children with septic shock

OBJECTIVE

To determine whether hsp70 is elevated in the plasma of children with septic shock.

DESIGN

Cohort study.

SETTING

Two academic, tertiary pediatric intensive care units.

PATIENTS

Ninety-four children admitted to the pediatric intensive care unit with septic shock and 24 control children undergoing elective surgical procedures.

INTERVENTIONS

Venous or arterial blood sampling.

MEASUREMENTS AND MAIN RESULTS

Children admitted to the pediatric intensive care unit with a diagnosis of septic shock were enrolled in the study following written informed consent. The control group consisted of healthy children undergoing elective surgical procedures. Blood samples from children in the septic shock or control groups were obtained within 24 hrs of admission to the pediatric intensive care unit or during the preoperative visit. Samples were collected, centrifuged, and stored at -70 degrees C. The hsp70 levels were measured using a commercially available enzyme-linked immunosorbent assay. Results were analyzed by Wilcoxon's rank sum test. Extracellular hsp70 levels in children with septic shock were significantly elevated compared with control patients (51.6 ng/mL vs. 8.1 ng/mL, respectively, p = .0004).

CONCLUSIONS

Extracellular hsp70 levels are significantly elevated in children with septic shock compared with controls. Given the newly described cell signaling properties of hsp70, these data suggest that extracellular hsp70 may play a role in the host response during septic shock.

Activated protein C inhibits local coagulation after intrapulmonary delivery of endotoxin in humans

RATIONALE

Acute lung injury and pneumonia are associated with pulmonary activation of coagulation and suppression of fibrinolysis, resulting in fibrin deposition in the lung. Activated protein C (APC) has systemic anticoagulant effects in patients with sepsis.

OBJECTIVE

To determine the effect of systemic administration of recombinant human APC on endotoxin-induced hemostatic alterations in the bronchoalveolar space in humans.

METHODS

Healthy humans received intravenous APC (24 microg/kg/hour; n = 8) or vehicle (n = 7); all subjects were administered saline in one lung subsegment and endotoxin (4 ng/kg) into the contralateral lung. Bronchoalveolar lavage was performed 16 hours after saline and endotoxin administration.

MEASUREMENTS AND MAIN RESULTS

Endotoxin induced local activation of coagulation, as reflected by elevated levels of thrombin-antithrombin complexes (1.9 +/- 0.1 ng/ml) and soluble tissue factor (15.0 +/- 0.6 pg/ml) in bronchoalveolar lavage fluid, which was inhibited by APC (1.4 +/- 0.1 ng/ml and 12.3 +/- 0.4 pg/ml, respectively; both p < 0.01). Concurrently, endotoxin suppressed fibrinolysis, as indicated by reduced bronchoalveolar levels of plasminogen activator activity accompanied by elevated levels of plasminogen activator inhibitor type I activity. APC diminished the rise in plasminogen activator inhibitor type I activity (from 3.9 +/- 0.1 to 3.0 +/- 0.2 ng/ml, p = 0.002), while not significantly influencing plasminogen activator activity levels. Endotoxin reduced bronchoalveolar protein C concentrations, which was prevented by APC. Protein C did not influence the endotoxin-induced rise in local soluble thrombomodulin levels.

CONCLUSION

APC exerts an anticoagulant effect in the human lung challenged with endotoxin.

Antithrombotic agents in the treatment of severe sepsis

Sepsis, a systemic inflammatory syndrome, is a response to infection and when associated with multiple organ dysfunction is termed severe sepsis. It remains a leading cause of mortality in the critically ill. The response to the invading microorganisms may be considered as a balance between a pro-inflammatory and an anti-inflammatory reaction. While an inadequate pro-inflammatory reaction and a strong anti-inflammatory response could lead to overwhelming infection and the death of the patient, a strong and uncontrolled pro-inflammatory response, manifested by the release of pro-inflammatory mediators may lead to microvascular thrombosis and multiple organ failure. Endotoxin triggers sepsis via the release of various mediators such as tumour necrosis factor-alpha and interleukin-1 (IL-1). These cytokines activate the complement and coagulation systems, release adhesion molecules, prostaglandins, leukotrienes, reactive oxygen species and nitric oxide. Other mediators involved in the sepsis syndrome include IL-1, -6 and -8; arachidonic acid metabolites; platelet activating factor; histamine; bradykinin; angiotensin; complement components and vasoactive intestinal peptide. These pro-inflammatory responses are counteracted by IL-10. Most of the trials targeting the different mediators of the pro-inflammatory response have failed due to a lack of correct definition of sepsis. Understanding the exact pathophysiology of the disease will enable more advanced treatment options. Targeting the coagulation system with various anticoagulant agents including, activated protein C, and tissue factor pathway inhibitor (TFPI) is a rational approach. Many clinical trials have been conducted to evaluate these agents in severe sepsis. While trials on antithrombin and TFPI were not so successful, the double-blind, placebo-controlled, Phase III trial of recombinant human activated Protein C Worldwide Evaluation in Severe Sepsis (PROWESS) was successful, creating a significant decrease in mortality when compared to the placebo group. A better understanding of the pathophysiologic mechanism of severe sepsis will provide better treatment options, and combination antithrombotic treatment may provide a multipronged approach for the treatment of severe sepsis.

International pediatric sepsis consensus conference: definitions for sepsis and organ dysfunction in pediatrics

OBJECTIVE

Although general definitions of the sepsis continuum have been published for adults, no such work has been done for the pediatric population. Physiologic and laboratory variables used to define the systemic inflammatory response syndrome (SIRS) and organ dysfunction require modification for the developmental stages of children. An international panel of 20 experts in sepsis and clinical research from five countries (Canada, France, Netherlands, United Kingdom, and United States) was convened to modify the published adult consensus definitions of infection, sepsis, severe sepsis, septic shock, and organ dysfunction for children.

DESIGN

Consensus conference.

METHODS

This document describes the issues surrounding consensus on four major questions addressed at the meeting: a) How should the pediatric age groups affected by sepsis be delineated? b) What are the specific definitions of pediatric SIRS, infection, sepsis, severe sepsis, and septic shock? c) What are the specific definitions of pediatric organ failure and the validity of pediatric organ failure scores? d) What are the appropriate study populations and study end points required to successfully conduct clinical trials in pediatric sepsis? Five subgroups first met separately and then together to evaluate the following areas: signs and symptoms of sepsis, cell markers, cytokines, microbiological data, and coagulation variables. All conference participants approved the final draft of the proceedings of the meeting.

RESULTS

Conference attendees modified the current criteria used to define SIRS and sepsis in adults to incorporate pediatric physiologic variables appropriate for the following subcategories of children: newborn, neonate, infant, child, and adolescent. In addition, the SIRS definition was modified so that either criteria for fever or white blood count had to be met. We also defined various organ dysfunction categories, severe sepsis, and septic shock specifically for children. Although no firm conclusion was made regarding a single appropriate study end point, a novel nonmortality end point, organ failure-free days, was considered optimal for pediatric clinical trials given the relatively low incidence of mortality in pediatric sepsis compared with adult populations.

CONCLUSION

We modified the adult SIRS criteria for children. In addition, we revised definitions of severe sepsis and septic shock for the pediatric population. Our goal is for these first-generation pediatric definitions and criteria to facilitate the performance of successful clinical studies in children with sepsis.

Coagulation and fibrinolysis in human acute lung injury-New therapeutic targets?

Acute lung injury (ALI) and acute respiratory distress syndrome (ARDS) are common, life-threatening causes of acute respiratory failure that arise from a variety of local and systemic insults. The need for new specific therapies has led a number of investigators to examine the role of altered coagulation and fibrinolysis in the pathogenesis of ALI/ARDS. This review summarizes our current understanding of coagulation and fibrinolysis in human ALI/ARDS with an emphasis on pathways that could be potential therapeutic targets including the tissue factor pathway, the protein C pathway and modulation of fibrinolysis via plasminogen activator inhibitor-1. The available data suggest that clinical ALI and ARDS are characterized by profound alterations in both systemic and intra-alveolar coagulation and fibrinolysis. Fibrin deposition in the airspaces and lung microvasculature likely results from both activation of the coagulation cascade and impaired fibrinolysis, triggered by inflammation. Modulation of fibrin deposition in the lung through targeting activation and modulation of coagulation as well as fibrinolysis may be an important therapeutic target in clinical ALI/ARDS that deserves further exploration.

Drotrecogin alfa: a role in emergency department treatment of severe sepsis?

Human protein C is a serine protease that circulates in the blood as an inactive zymogen. It is converted to its active form by interaction with thrombomodulin on the endothelial wall. Activated protein C has a significant role in maintaining haemostasis, and is a major mechanism of controlling microvascular thrombosis. Recent reports describe the use of drotrecogin alfa (recombinant activated protein C) in severe sepsis, a condition relevant to emergency medicine. This review describes the physiology of the protein C pathway and its importance in sepsis. It will also focus on the use of drotrecogin alfa in sepsis, and its use in the ED.

Safety, pharmacokinetics, and pharmacodynamics of drotrecogin alfa (activated) in children with severe sepsis

OBJECTIVE

In a phase 3 trial, recombinant human activated protein C (drotrecogin alfa [activated]) significantly reduced mortality in adult patients with severe sepsis. We have now performed a preliminary analysis of the safety, pharmacokinetics, and pharmacodynamics of drotrecogin alfa (activated) in pediatric patients with severe sepsis.

DESIGN AND SETTING

Open-label, nonrandomized, sequential, 2-part study conducted in 11 medical centers in the United States and United Kingdom.

PATIENTS

Eighty-three pediatric patients with severe sepsis aged term newborn (>or=38 weeks' gestation) to <18 years old.

INTERVENTION

In part 1, drotrecogin alfa (activated) was administered as escalating doses of 6, 12, 24, and 36 micro g/kg per hour for 6 hours for each patient (n = 21). In part 2, drotrecogin alfa (activated) was infused at a rate of 24 micro g/kg per hour for 96 hours in 62 patients.

MAIN OUTCOME MEASURES

Plasma clearance, plasma concentration, D-dimer, protein C, and antithrombin levels were measured, and adverse events were monitored.

RESULTS

The trial enrolled 83 pediatric patients with severe sepsis, aged term newborn (>or=38 weeks' gestation) to <18 years. In part 1, a dose of 24 micro g/kg per hour produced steady-state plasma concentrations of activated protein C similar to those attained in equivalently dosed adult severe sepsis patients. For all pediatric patients dosed at 24 micro g/kg per hour, the median weight-normalized clearance was 0.45 L/hour/kg and the median steady-state concentration was 51.3 ng/mL. The mean plasma half-life was 30 minutes. Weight-normalized clearance in pediatric and adult patients did not differ significantly with age or weight. D-dimer levels decreased 26% from baseline to end of infusion. Baseline levels of protein C and antithrombin increased 79% and 24%, respectively, over the 96-hour treatment period in part 2. The incidence of serious bleeding during infusion and during the entire study period was 2.4% and 4.8%, respectively.

CONCLUSIONS

Pediatric patients with severe sepsis manifest sepsis-induced coagulopathy including protein C deficiency comparable to that seen in adults with severe sepsis. The pharmacokinetics, pharmacodynamic effects, and safety profile of drotrecogin alfa (activated) in pediatric patients are similar to those previously published for adult patients. A large, phase 3, randomized, placebo-controlled study is ongoing to confirm these results and formally assess the safety and efficacy of drotrecogin alfa (activated) in children.

Protein C and thrombomodulin in human acute lung injury

Decreased circulating protein C and increased circulating thrombomodulin are markers of the prothrombotic, antifibrinolytic state associated with poor outcomes in sepsis but have not been measured in patients with ALI (acute lung injury)/ARDS (acute respiratory distress syndrome). We measured circulating and intra-alveolar protein C and thrombomodulin in 45 patients with ALI/ARDS from septic and nonseptic causes and correlated the levels with clinical outcomes. Plasma protein C levels were lower in ALI/ARDS compared with normal. Lower levels of protein C were associated with worse clinical outcomes, including death, fewer ventilator-free days, and more nonpulmonary organ failures, even when only patients without sepsis were analyzed. Levels of thrombomodulin in pulmonary edema fluid from ALI/ARDS patients were >10-fold higher than normal plasma and 2-fold higher than ALI/ARDS plasma. Higher edema fluid thrombomodulin levels were associated with worse clinical outcomes. The higher levels in edema fluid compared with plasma suggest local release of soluble thrombomodulin in the lung, possibly from a lung epithelial source. To determine whether lung epithelial cells can release thrombomodulin, A549 cells and primary isolates of human alveolar type II cells were exposed to H2O2 or inflammatory cytokines. Both epithelial cell types released thrombomodulin into the media. In summary, the protein C system is markedly disrupted in patients with ALI/ARDS from both septic and nonseptic causes. The protein C system may be a potential therapeutic target in patients with ALI/ARDS.

Coagulation dysfunction in sepsis and multiple organ system failure

In patients diagnosed with sepsis, severe sepsis or septic shock, cytokine-mediated endothelial injury, and TF activation initiate a cascade of events that culminate in the development of coagulation dysfunction characterized as procoagulant and antifibrinolytic. This abnormal state predisposes the patient to develop microvascular thrombosis, tissue ischemia, and organ hypoperfusion. Multiple organ dysfunction syndrome may be a product of this pertubation in coagulation regulation. Treatments aimed at correcting this coagulation dysfunction have met with mixed success. Current data suggest that AT III replacement therapy has limited efficacy in adults with severe sepsis. In contrast, adult patients diagnosed with severe sepsis and organ failure and treated with aPC (drotrecogin alfa activate) have a significantly reduced risk of death when compared with placebo-treated patients. A phase III trial examining the efficacy of protein C replacement therapy in pediatric patients with severe sepsis and organ failure is underway.

Bench-to-bedside review: functional relationships between coagulation and the innate immune response and their respective roles in the pathogenesis of sepsis

The innate immune response system is designed to alert the host rapidly to the presence of an invasive microbial pathogen that has breached the integument of multicellular eukaryotic organisms. Microbial invasion poses an immediate threat to survival, and a vigorous defense response ensues in an effort to clear the pathogen from the internal milieu of the host. The innate immune system is able to eradicate many microbial pathogens directly, or innate immunity may indirectly facilitate the removal of pathogens by activation of specific elements of the adaptive immune response (cell-mediated and humoral immunity by T cells and B cells). The coagulation system has traditionally been viewed as an entirely separate system that has arisen to prevent or limit loss of blood volume and blood components following mechanical injury to the circulatory system. It is becoming increasingly clear that coagulation and innate immunity have coevolved from a common ancestral substrate early in eukaryotic development, and that these systems continue to function as a highly integrated unit for survival defense following tissue injury. The mechanisms by which these highly complex and coregulated defense strategies are linked together are the focus of the present review.

Markers of endothelial damage in organ dysfunction and sepsis

OBJECTIVES

To review the literature on direct and indirect markers of endothelial activation and damage in patients with sepsis and systemic inflammation and to assess their clinical usefulness for diagnosis and outcome. Various markers derived from or activated by endothelial cells are described, such as adhesion molecules, thrombomodulin, von Willebrand factor, parameters of the coagulation system, and interleukin-6. Furthermore, the association of these markers with the severity of sepsis, systemic inflammation, and outcome is evaluated.

DATA EXTRACTION AND SYNTHESIS

Published research and review articles related to these parameters, with special emphasis on clinical studies.

CONCLUSIONS

Endothelial activation and damage occur early during sepsis and play a major role in the pathophysiology of systemic inflammation. Various markers of endothelial activation are increased during sepsis and systemic inflammation, and in most studies, the level of markers such as soluble intercellular adhesion molecule, vascular cell adhesion molecule, and E selectin correlate well with the severity of inflammation and the course of the disease. However, to date, it remains unclear whether adhesion molecules and coagulation parameters are superior in this respect to interleukin-6 and procalcitonin, as direct comparisons are lacking. In addition, it is evident that markers of endothelial activation and coagulation parameters lack specificity for infection-induced endothelial damage and organ dysfunction.

Soluble thrombomodulin plasma levels are an early indication of a lethal course in human acute pancreatitis

BACKGROUND

The potential to predict severe disease and lethality by using plasma soluble thrombomodulin (sTM) and C-reactive protein (CRP) levels in 73 patients with acute pancreatitis was analyzed in a prospective 5-year investigation performed at a single institution.

METHODS

According to the Atlanta criteria, pancreatitis was classified as mild in 23 patients and as severe in 50 patients. Blood was collected on days 1, 3, 5, 7, 10, 14, 21, and 28 after the onset of pain and analyzed for sTM and CRP.

RESULTS

During the period between days 3 and 10 of acute pancreatitis when most of the admissions occurred, sTM levels at a cutoff of 75 ng/mL on day 3 (sensitivity, 100%; specificity, 77%; positive predictive value, 38%; negative predictive value, 100%) and 71 ng/mL on day 10 (sensitivity, 100%; specificity, 77%; positive predictive value, 41%; negative predictive value, 100%) were predictive of a lethal outcome. With sTM levels, it was not possible to differentiate patients with mild pancreatitis from those with severe pancreatitis (Atlanta classification). In contrast, CRP levels at a cutoff of 113 mg/L on day 3 differentiated severe from mild courses with a diagnostic sensitivity of 84%, a specificity of 60%, a positive predictive value of 78%, and a negative predictive value of 69%. CRP levels at a cutoff of 122 mg/L on day 10 differentiated mild from severe courses (nonsurvivors) with a diagnostic sensitivity of 72%, a specificity of 72%, a positive predictive value of 86%, and a negative predictive value of 53%. In contrast, differentiation of mild forms of acute pancreatitis from severe pancreatitis (survivors) on day 10 was not possible.

CONCLUSIONS

CRP is a valuable marker of disease severity in acute pancreatitis especially in the first period of pancreatitis, whereas sTM identifies early those patients with the most severe courses and a high risk of dying (negative predictive value, 100%). Determination of sTM in addition to CRP offers the opportunity of identifying early those patients who require intensive care most urgently. Of course, further investigations of sTM in acute pancreatitis are indicated to confirm our results.

Dysfunction of endothelial protein C activation in severe meningococcal sepsis

BACKGROUND

Impairment of the protein C anticoagulation pathway is critical to the thrombosis associated with sepsis and to the development of purpura fulminans in meningococcemia. We studied the expression of thrombomodulin and the endothelial protein C receptor in the dermal microvasculature of children with severe meningococcemia and purpuric or petechial lesions.

METHODS

We assessed the integrity of the endothelium and the expression of thrombomodulin and the endothelial protein C receptor in biopsy specimens of purpuric lesions from 21 children with meningococcal sepsis (median age, 41 months), as compared with control skin-biopsy specimens.

RESULTS

The expression of endothelial thrombomodulin and of the endothelial protein C receptor was lower in the patients with meningococcal sepsis than in the controls, both in vessels with thrombosis and in vessels without thrombosis. On electron microscopical examination, the endothelial cells were generally intact in both thrombosed and nonthrombosed vessels. Plasma thrombomodulin levels in the children with meningococcal sepsis (median, 6.4 ng per liter) were higher than those in the controls (median, 3.6 ng per liter; P=0.002). Plasma levels, protein C antigen, protein S antigen, and antithrombin antigen were lower than those in the controls. In two patients treated with unactivated protein C concentrate, activated protein C was undetectable at the time of admission, and plasma levels remained low.

CONCLUSIONS

In severe meningococcal sepsis, protein C activation is impaired, a finding consistent with down-regulation of the endothelial thrombomodulin-endothelial protein C receptor pathway.

Activated protein C versus protein C in severe sepsis

OBJECTIVE

To delineate critical differences between activated protein C (APC) and its precursor, protein C, with regard to plasma levels in health and in severe sepsis, and to discuss the implications of these differences as they relate to treatment strategies in patients with severe sepsis. DATA SOURCE/STUDY SELECTION: Published literature including abstracts, manuscripts, and review articles reporting studies in both experimental animal models and humans that provide an understanding of the relationship and the critical differences between circulating levels of APC and protein C.

DATA EXTRACTION AND SYNTHESIS

The protein C pathway represents one of the major regulatory systems of hemostasis, exhibiting antithrombotic, profibrinolytic and anti-inflammatory properties. This pathway also plays a critical role in the pathophysiology of severe sepsis. Central to this pathway is the vitamin K-dependent serine protease, APC, and its precursor, protein C. The conversion of protein C to APC is dependent on the complex of thrombin and thrombomodulin, an integral endothelial surface receptor. The conversion of protein C to APC is further augmented by another endothelial surface protein, the endothelial protein C receptor. There are limited published data on APC levels in health and disease, probably due to the complexity of the assay methodology for measuring APC and the absence of commercially available diagnostic kits. In animals and humans with normal functioning endothelium, circulating levels of APC (1-3 ng/mL) are positively correlated with protein C (4000-5000 ng/mL) concentration and the amount of thrombin generated. In patients with severe sepsis, there is a generalized endothelial dysfunction, contributing to multiple organ failure with increased morbidity and mortality. Persistently low protein C levels are related to poor prognosis. Key to understanding the treatment strategy with APC or protein C is knowledge of the functional status of the endothelium and, specifically, whether the microvasculature in patients with severe sepsis can support the conversion of protein C to APC. To date, only APC (drotrecogin alfa [activated]) has been shown to reduce mortality in severe sepsis in a large, phase 3, placebo-controlled, double-blind international trial. In contrast, no data, other than open-label case studies, are available for evaluation of the effects of protein C in the treatment of severe sepsis.

CONCLUSION

The limited data available indicate that lower levels of protein C in sepsis occur in the absence of appreciable conversion to APC. These observations indicate that treatment with APC may be more efficacious than protein C in severe sepsis, where generalized endothelial dysfunction may impair conversion of protein C to APC. Additional research is required to confirm these observations.

Endothelial cell dysfunction and coagulation

OBJECTIVES

a) To review endothelial properties and to establish how these unperturbed properties contribute to the maintenance of endothelium anticoagulant activity; b) to better understand the relative contributions of endothelial cells and monocytes in sepsis-induced altered coagulation.

DATA SOURCES

A summary of published literature from MEDLINE search files and other original articles and reviews published on endothelial cell and monocyte functions and modifications owing to sepsis.

DATA EXTRACTION AND SYNTHESIS

Unperturbed endothelial cells provide anticoagulant properties; exposure to inflammatory and/or septic stimuli can rapidly lead to procoagulant behavior. Sepsis alters endothelial cell surface and induces tissue factor synthesis at the endothelial and subendothelial levels. During endotoxemia, endothelial cells generate adhesion molecules that bind leukocytes and monocytes, increasing local procoagulant reactions. Tissue factor expression is also increased at the level of the monocyte; the relative importance of endothelial injury and monocyte activation in coagulation disorders was recently assessed. Endothelium protection before induction of septic shock was not associated with any reduction in monocyte tissue factor expression, suggesting that altered coagulation was present despite normal endothelial cell function. On the other hand, decreased monocyte tissue factor expression was associated with a marked reduction in endothelial injury, increased endothelium-derived relaxation, and improved survival rate in treated animals.

CONCLUSIONS

This review suggests that monocyte activation and tissue factor expression may be of paramount importance in sepsis-associated injuries and that coagulation activation may contribute to the endothelial cell injury observed during sepsis. Endothelial injury, in turn, exacerbates sepsis-induced coagulation abnormalities.

Improving the outcome of septic shock in children

Sepsis is an important cause of pediatric morbidity and mortality. Improving the outcome of pediatric sepsis requires diverse efforts, including prevention, early recognition, improvements in early management and transport, and physiology-directed care. Awareness that septic shock represents a pathophysiologic host response to infection has prompted investigation of immune mediators and coagulation factors as potential targets for anti-sepsis therapies. Advancements thus far include: the potential prevention of neonatal sepsis with granulocyte colony-stimulating factor; recognition of clindamycin as a potential inhibitor of endotoxin release; improved outcome from meningococcal disease in children treated with bactericidal/permeability-increasing protein (rBPI21); and improved outcome from sepsis in premature infants treated with pentoxifylline. Further randomized controlled studies of immunomodulatory agents are indicated and a few are in progress. Current studies on genetic propensities in cytokine and coagulation protein expression may explain variability in patient outcomes and eventually lead to genomics-based therapeutics.