accumulate in large organs during meningococcal sepsis.

Background: (Nm) is the cause of epidemic meningitis and fulminant meningococcal septicemia. The clinical presentations and outcome of meningococcal septic shock is closely related to the circulating levels of lipopolysaccharides (LPS) and of DNA (Nm DNA). We have previously explored the distribution of Nm DNA in tissues from large organs of patients dying of meningococcal septic shock and in a porcine meningococcal septic shock model.

Transcriptomic changes in the large organs in lethal meningococcal shock are reflected in a porcine shock model.

Background: Fulminant meningococcal sepsis with shock and multiple organ failure is associated with a massive systemic inflammatory response involving solid organs. We have previously established a porcine model of the disease to study pathophysiologic and possible therapeutic strategies.

Objective: This study examined whether the organ specific gene expression profile in such a large animal model reflects the profile seen in patients with fulminant meningococcal sepsis.

Choice of immunoassay to evaluate porcine cytokine levels.

Background: In order to adequately monitor cytokines in experimental models, currently available methods and commercially available kits should be compared.

Aim: To compare the plasma and tissue concentrations of IL-1β, IL-6, IL-8, IL-10, and TNF as a measure of systemic inflammation in septic pigs.

Methods: Cytokines were quantified from blood and tissue samples obtained at 0, 60, 120, 180, and 240 min, and in postmortem biopsies of the liver, kidney, lung, heart, and spleen from 26 anesthetized landrace pigs.

Extensive Changes in Transcriptomic "Fingerprints" and Immunological Cells in the Large Organs of Patients Dying of Acute Septic Shock and Multiple Organ Failure Caused by .

Patients developing meningococcal septic shock reveal levels of (10-10/mL) and endotoxin (10-10 EU/mL) in the circulation and organs, leading to acute cardiovascular, pulmonary and renal failure, coagulopathy and a high case fatality rate within 24 h. To investigate transcriptional profiles in heart, lungs, kidneys, liver, and spleen and immunostain key inflammatory cells and proteins in post mortem formalin-fixed, paraffin-embedded (FFPE) tissue samples from meningococcal septic shock patients. Total RNA was isolated from FFPE and fresh frozen (FF) tissue samples from five patients and two controls (acute non-infectious death).

Traceability and distribution of DNA in archived post mortem tissue samples from patients with systemic meningococcal disease.

Background: The pathophysiology and outcome of meningococcal septic shock is closely associated with the plasma level of lipopolysaccharides (LPS, endotoxin) and the circulating level of meningococcal DNA. The aim of the present study was to quantify the number of in different formalin-fixed, paraffin-embedded (FFPE) tissue samples and fresh frozen (FF) tissue samples from patients with systemic meningococcal disease (SMD), to explore the distribution of in the body.

Methods: DNA in FFPE and FF tissue samples from heart, lungs, liver, kidneys, spleen and brain from patients with meningococcal shock and controls (lethal pneumococcal infection) stored at variable times, were isolated.

Combined inhibition of C5 and CD14 efficiently attenuated the inflammatory response in a porcine model of meningococcal sepsis.

Background: Fulminant meningococcal sepsis, characterized by overwhelming innate immune activation, mostly affects young people and causes high mortality. This study aimed to investigate the effect of targeting two key molecules of innate immunity, complement component C5, and co-receptor CD14 in the Toll-like receptor system, on the inflammatory response in meningococcal sepsis.

Methods: Meningococcal sepsis was simulated by continuous intravenous infusion of an escalating dose of heat-inactivated administered over 3 h.

Properdin binding to complement activating surfaces depends on initial C3b deposition.

Two functions have been assigned to properdin; stabilization of the alternative convertase, C3bBb, is well accepted, whereas the role of properdin as pattern recognition molecule is controversial. The presence of nonphysiological aggregates in purified properdin preparations and experimental models that do not allow discrimination between the initial binding of properdin and binding secondary to C3b deposition is a critical factor contributing to this controversy. In previous work, by inhibiting C3, we showed that properdin binding to zymosan and Escherichia coli is not a primary event, but rather is solely dependent on initial C3 deposition.

Massive Organ Inflammation in Experimental and in Clinical Meningococcal Septic Shock.

Fulminant meningococcal sepsis is characterized by a massive growth of bacteria in the circulation, regarded as the primary inflammatory site, with no specific solid organ focus. Here we aimed to study the local inflammatory response in organs using a porcine model of fulminant meningococcal septic shock challenged with exponentially increasing doses of heat inactivated Neisseria meningitidis. The results were compared with those obtained in organs post mortem from three patients with lethal meningococcal septic shock.

A complement C5 gene mutation, c.754G>A:p.A252T, is common in the Western Cape, South Africa and found to be homozygous in seven percent of Black African meningococcal disease cases.

Patients with genetically determined deficiency of complement component 5 are usually diagnosed because of recurrent invasive Neisseria meningitidis infections. Approximately 40 individual cases have been diagnosed worldwide. Nevertheless, reports of the responsible genetic defects have been sporadic, and we know of no previous reports of C5 deficiency being associated with a number of independent meningococcal disease cases in particular communities.

Systemic CD14 inhibition attenuates organ inflammation in porcine Escherichia coli sepsis.

Sepsis is an infection-induced systemic inflammatory response syndrome. Upstream recognition molecules, like CD14, play key roles in the pathogenesis. The aim of the present study was to investigate the effect of systemic CD14 inhibition on local inflammatory responses in organs from septic pigs.

Combined inhibition of complement C5 and CD14 markedly attenuates inflammation, thrombogenicity, and hemodynamic changes in porcine sepsis.

Complement and the TLR family constitute two important branches of innate immunity. We previously showed attenuating effects on inflammation and thromogenicity by inhibiting the TLR coreceptor CD14 in porcine sepsis. In the present study, we explored the effect of the C5 and leukotriene B4 inhibitor Ornithodoros moubata complement inhibitor (OmCI; also known as coversin) alone and combined with anti-CD14 on the early inflammatory, hemostatic, and hemodynamic responses in porcine Escherichia coli-induced sepsis.

Activation of coagulation and platelets by candidate membranes of implantable devices in a whole blood model without soluble anticoagulant.

Implantable devices are challenged with thrombus formation at their biomaterial interface. Thus the importance of identifying compatible biomaterials that will help to improve the performance of these devices are becoming increasingly paramount. The aim of this study was to evaluate the activation of coagulation and platelets by candidate membranes considered for use in implantable devices on the basis of an adapted whole blood model without soluble anticoagulants.

Polyvalent immunoglobulin significantly attenuated the formation of IL-1β in Escherichia coli-induced sepsis in pigs.

Evidence suggests that adjunctive treatment with intravenous immunoglobulin preparations enriched with IgA and IgM reduce mortality in sepsis. The mode of action of polyvalent immunoglobulin is complex, including neutralization of toxins and modulation of complement activation and cytokine formation toward an anti-inflammatory profile. In this study we explored the effect of Pentaglobin, containing IgG, IgA and IgM, on the initial inflammatory reaction as well as on hemodynamics, using a well characterized and standardized porcine model of sepsis.

Inflammatory response induced by candidate biomaterials of an implantable microfabricated sensor.

The implantation of synthetic medical devices is known to generate an immediate and complex material-related inflammatory response. Consequently, 15 candidate materials for a new microfabricated sensor were investigated. A human whole blood model that permits the interaction of all the putative inflammatory systems was used.

Activation of polymorphonuclear leukocytes by candidate biomaterials for an implantable glucose sensor.

Background: Continuous monitoring of glucose by implantable microfabricated devices offers key advantages over current transcutaneous glucose sensors that limit usability due to their obtrusive nature and risk of infection. A successful sensory implant should be biocompatible and retain long-lasting function. Polymorphonuclear leukocytes (PMN) play a key role in the inflammatory system by releasing enzymes, cytokines, and reactive oxygen species, typically as a response to complement activation.

The role of bradykinin and the effect of the bradykinin receptor antagonist icatibant in porcine sepsis.

Bradykinin (BK) is regarded as an important mediator of edema, shock, and inflammation during sepsis. In this study, we evaluated the contribution of BK in porcine sepsis by blocking BK and by measuring the stable BK metabolite, BK1-5, using anesthetized pigs. The effect of BK alone, the efficacy of icatibant to block this effect, and the recovery of BK measured as plasma BK1-5 were first investigated.

Neisseria meningitidis and Escherichia coli are protected from leukocyte phagocytosis by binding to erythrocyte complement receptor 1 in human blood.

The initial interaction of Gram-negative bacteria with erythrocytes and its implications on leukocyte phagocytosis and oxidative burst in human whole blood were examined. Alexa-labeled Escherichia coli, wild-type H44/76 N. meningitidis and the H44/76lpxA lipopolysaccharide (LPS)-deficient mutant were incubated with whole blood using lepirudin as anticoagulant which has no adverse effects on complement.

Complement activation by candidate biomaterials of an implantable microfabricated medical device.

Implantable devices realized by microfabrication have introduced a new class of potential biomaterials whose properties would need to be assessed. Such devices include sensors for measuring biological substances like glucose. Thus, 14 different candidate materials intended for design of such a device were investigated with respect to their complement activation potential in human serum.

Dissecting the effects of lipopolysaccharides from nonlipopolysaccharide molecules in experimental porcine meningococcal sepsis.

Objective: To dissect the in vivo responses to lipopolysaccharide compared with nonlipopolysaccharide structures of whole meningococci.

Design: Comparative experimental study.

Setting: University hospital with an animal intensive care unit and laboratory.

Critical roles of complement and antibodies in host defense mechanisms against Neisseria meningitidis as revealed by human complement genetic deficiencies.

Certain complement defects are associated with an increased propensity to contract Neisseria meningitidis infections. We performed detailed analyses of complement-mediated defense mechanisms against N. meningitidis 44/76 with whole blood and serum from two adult patients who were completely C2 or C5 deficient.

CD14 inhibition efficiently attenuates early inflammatory and hemostatic responses in Escherichia coli sepsis in pigs.

Sepsis is a severe infection-induced systemic inflammatory syndrome. Inhibition of downstream inflammatory mediators of sepsis, e.g.

Human genetic deficiencies reveal the roles of complement in the inflammatory network: lessons from nature.

Complement component C5 is crucial for experimental animal inflammatory tissue damage; however, its involvement in human inflammation is incompletely understood. The responses to gram-negative bacteria were here studied taking advantage of human genetic complement-deficiencies--nature's own knockouts--including a previously undescribed C5 defect. Such deficiencies provide a unique tool for investigating the biological role of proteins.

A new dynamic porcine model of meningococcal shock.

The objective of this study was to establish a porcine analog of human meningococcal sepsis for pathophysiological investigations and possible future therapy in severe sepsis. Heat-killed Neisseria meningitidis was continuously infused in sublethal concentrations into 10 anesthetized 30-kg pigs (sepsis group). The dose was doubled every 30 min.

Stages of meningococcal sepsis simulated in vitro, with emphasis on complement and Toll-like receptor activation.

The clinical presentation of meningococcal disease is closely related to the number of meningococci in the circulation. This study aimed to examine the activation of the innate immune system after being exposed to increasing and clinically relevant concentrations of meningococci. We incubated representative Neisseria meningitidis serogroup B (ST-32) and serogroup C (ST-11) strains and a lipopolysaccharide (LPS)-deficient mutant (the 44/76 lpxA mutant) in human serum and whole blood and measured complement activation and cytokine secretion and the effect of blocking these systems.

New biomarkers in an acute model of live Escherichia coli-induced sepsis in pigs.

We developed a live Escherichia coli model of acute sepsis in pigs with emphasize on biomarkers reflecting the early inflammatory response of sepsis. Healthy pigs, 25-35 kg, were challenged intravenously (IV) (n = 12) or intrapulmonary (n = 6) with live E. coli and observed for 3 and 5 h respectively.