Effect of the anticoagulant, storage time and temperature of blood samples on the concentrations of 27 multiplex assayed cytokines - Consequences for defining reference values in healthy humans

Cytokines are potentially useful biomarkers of sepsis and other inflammatory conditions. Many cytokines can be released by leukocytes and platelets after sampling. The sampling and processing techniques are consequently critically important to measure the in vivo levels. We therefore examined the effects of four different anticoagulants, EDTA, citrate, lepirudin, heparin compared to serum, on the levels of 27 different cytokines. The effects of storage temperature, freezing and thawing on the plasma cytokines were examined. Cytokines were analysed using a multiplex immunoassay. The cytokine levels in serum were significantly higher compared with plasma, consistent with release of cytokines in vitro during coagulation. In general, the lowest values for all cytokines were found in EDTA samples, stored on crushed ice, centrifuged within 4h and thereafter stored at -80°C. MCP-1 and MIP-1β levels were highest in heparin plasma and storage of blood for up to 4h at room temperature significantly increased the interleukin (IL)-2, IL-6, IL-8, IFN-γ and GM-CSF levels in EDTA plasma, indicating post-sampling release. In contrast, the IP-10 levels were unaffected by sample storage at both temperatures. Our results indicate that the cytokines were more stable in plasma than in whole blood after sampling. Thus, cytokines should be analysed in EDTA plasma samples stored on ice and centrifuged within 4h. Based on these data, the reference ranges of 27 cytokines in EDTA plasma in 162 healthy human donors were calculated.

Iron oxide nanoparticles induce cytokine secretion in a complement-dependent manner in a human whole blood model

Iron oxide nanoparticles (IONPs) are promising nanomaterials for biomedical applications. However, their inflammatory potential has not been fully established. Here, we used a lepirudin anti-coagulated human whole blood model to evaluate the potential of 10 nm IONPs to activate the complement system and induce cytokine production. Reactive oxygen species and cell death were also assessed. The IONPs activated complement, as measured by C3a, C5a and sC5b-9, and induced the production of pro-inflammatory cytokines in a particle-dose dependent manner, with the strongest response at 10 µg/mL IONPs. Complement inhibitors at C3 (compstatin analog Cp40) and C5 (eculizumab) levels completely inhibited complement activation and secretion of inflammatory mediators induced by the IONPs. Additionally, blockade of complement receptors C3aR and C5aR1 significantly reduced the levels of various cytokines, indicating that the particle-induced secretion of inflammatory mediators is mainly C5a and C3a mediated. The IONPs did not induce cell death or reactive oxygen species, which further suggests that complement activation alone was responsible for most of the particle-induced cytokines. These data suggest that the lepirudin anti-coagulated human whole blood model is a valuable ex vivo system to study the inflammatory potential of IONPs. We conclude that IONPs induce complement-mediated cytokine secretion in human whole blood.

Complement factor 5 blockade reduces porcine myocardial infarction size and improves immediate cardiac function

Inhibition of complement factor 5 (C5) reduced myocardial infarction in animal studies, while no benefit was found in clinical studies. Due to lack of cross-reactivity of clinically used C5 antibodies, different inhibitors were used in animal and clinical studies. Coversin (Ornithodoros moubata complement inhibitor, OmCI) blocks C5 cleavage and binds leukotriene B4 in humans and pigs. We hypothesized that inhibition of C5 before reperfusion will decrease infarct size and improve ventricular function in a porcine model of myocardial infarction. In pigs (Sus scrofa), the left anterior descending coronary artery was occluded (40 min) and reperfused (240 min). Coversin or placebo was infused 20 min after occlusion and throughout reperfusion in 16 blindly randomized pigs. Coversin significantly reduced myocardial infarction in the area at risk by 39% (p = 0.03, triphenyl tetrazolium chloride staining) and by 19% (p = 0.02) using magnetic resonance imaging. The methods correlated significantly (R = 0.92, p < 0.01). Tissue Doppler echocardiography showed increased systolic displacement (31%, p < 0.01) and increased systolic velocity (29%, p = 0.01) in coversin treated pigs. Interleukin-1β in myocardial microdialysis fluid was significantly reduced (31%, p < 0.05) and tissue E-selectin expression was significantly reduced (p = 0.01) in the non-infarcted area at risk by coversin treatment. Coversin ablated plasma C5 activation throughout the reperfusion period and decreased myocardial C5b-9 deposition, while neither plasma nor myocardial LTB4 were significantly reduced. Coversin substantially reduced the size of infarction, improved ventricular function, and attenuated interleukin-1β and E-selectin in this porcine model by inhibiting C5. We conclude that inhibition of C5 in myocardial infarction should be reconsidered.

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 Neisseria meningitidis administered over 3 h. The piglets were randomized, blinded to the investigators, to a positive control group (n = 12) receiving saline and to an interventional group (n = 12) receiving a recombinant anti-CD14 monoclonal antibody together with the C5 inhibitor coversin.

Results

A substantial increase in plasma complement activation in the untreated group was completely abolished in the treatment group (p = 0.006). The following inflammatory mediators were substantially reduced in plasma in the treatment group: Interferon-γ by 75% (p = 0.0001), tumor necrosis factor by 50% (p = 0.01), Interleukin (IL)-8 by 50% (p = 0.03), IL-10 by 40% (p = 0.04), IL-12p40 by 50% (p = 0.03), and granulocyte CD11b (CR3) expression by 20% (p = 0.01).

Conclusion

Inhibition of C5 and CD14 may be beneficial in attenuating the detrimental effects of complement activation and modulating the cytokine storm in patients with fulminant meningococcal sepsis.

Collectin Liver 1 and Collectin Kidney 1 of the Lectin Complement Pathway Are Associated With Mortality After Kidney Transplantation

Kidney transplanted patients still have significantly higher mortality compared with the general population. The innate immune system may play an important role during periods, with suppression of the adaptive immune system. In the present study, two soluble pattern recognition molecules of the innate immune system were investigated, collectin liver 1 (CL-L1) and collectin kidney 1 (CL-K1). Potential associations of their pretransplant levels and long-term graft and recipient survival were examined. The levels of CL-L1 and CL-K1 were measured at the time of transplantation in 382 patients (≥17 years) transplanted in 2000-2001. The cohort was subsequently followed until December 31, 2014. Data on patient and graft survival were obtained from the Norwegian Renal Registry. Both high CL-L1 (≥376 ng/mL) and high CL-K1 (≥304 ng/mL) levels were significantly associated with overall mortality in multivariate Cox analyses with hazard ration (HR) 1.50, 95% confidence interval (CI) 1.09-2.07, p = 0.013 and HR 1.43, 95% CI 1.02-1.99, p = 0.038, respectively. Moreover, high CL-K1 levels were significantly associated with cardiovascular mortality. No association between measured biomarkers and death-censored graft loss was found. Finally, there was a significant correlation between these two collectins, r = 0.83 (95% CI 0.80-0.86). In conclusion, CL-L1 and CL-K1 were significantly associated with mortality in kidney transplant recipients.

Systemic inflammation in acute intermittent porphyria: a case-control study

This study aimed to examine whether acute intermittent porphyria (AIP) is associated with systemic inflammation and whether the inflammation correlates with disease activity. A case-control study with 50 AIP cases and age-, sex- and place of residence-matched controls was performed. Plasma cytokines, insulin and C-peptide were analysed after an overnight fast using multiplex assay. Long pentraxin-3 (PTX3) and complement activation products (C3bc and TCC) were analysed using enzyme-linked immunosorbent assay (ELISA). Urine porphobilinogen ratio (U-PBG, µmol/mmol creatinine), haematological and biochemical tests were performed using routine methods. Questionnaires were used to register AIP symptoms, medication and other diseases. All 27 cytokines, chemokines and growth factors investigated were increased significantly in symptomatic AIP cases compared with controls (P < 0·0004). Hierarchical cluster analyses revealed a cluster with high visfatin levels and several highly expressed cytokines including interleukin (IL)-17, suggesting a T helper type 17 (Th17) inflammatory response in a group of AIP cases. C3bc (P = 0·002) and serum immunoglobulin (Ig)G levels (P = 0·03) were increased significantly in cases with AIP. The U-PBG ratio correlated positively with PTX3 (r = 0·38, P = 0·006), and with terminal complement complex (TCC) levels (r = 0·33, P = 0·02). PTX3 was a significant predictor of the biochemical disease activity marker U-PBG in AIP cases after adjustment for potential confounders in multiple linear regression analyses (P = 0·032). Prealbumin, C-peptide, insulin and kidney function were all decreased in the symptomatic AIP cases, but not in the asymptomatic cases. These results indicate that AIP is associated with systemic inflammation. Decreased C-peptide levels in symptomatic AIP cases indicate that reduced insulin release is associated with enhanced disease activity and reduced kidney function.

Plasma Levels of Marine n-3 Fatty Acids Are Inversely Correlated With Proinflammatory Markers sTNFR1 and IL-6 in Renal Transplant Recipients

OBJECTIVE

Marine n-3 polyunsaturated fatty acids (PUFAs) exert potential anti-inflammatory effects and might improve long-term outcomes after renal transplantation. We assessed associations between plasma phospholipid levels of marine n-3 PUFAs and plasma inflammatory biomarkers 10 weeks after renal transplantation.

DESIGN

Cross-sectional single-center study.

SUBJECTS

A study population of 861 renal transplant recipients transplanted at Oslo University Hospital between 2007 and 2011.

METHODS AND MAIN OUTCOME MEASURE

Plasma phospholipid fatty acids were determined by gas chromatography. Marine n-3 PUFA levels were defined as the sum of eicosapentaenoic acid, docosahexaenoic acid, and docosapentaenoic acid levels in weight percentage of total plasma phospholipid fatty acids. Plasma inflammatory biomarkers were measured by enzyme immunoassays. We used multivariable linear regression analysis to assess associations between levels of marine n-3 PUFAs and inflammatory biomarkers in plasma.

RESULTS

Plasma marine n-3 PUFA levels were inversely associated with plasma levels of proinflammatory biomarkers soluble tumor necrosis factor receptor 1 (standardized regression coefficient -0.11, P < .001) and interleukin-6 (standardized regression coefficient -0.09, P = .01). In contrast, there was no association between plasma levels of marine n-3 PUFAs and the anti-inflammatory mediator interleukin-10.

CONCLUSIONS

In this renal transplant cohort, inverse associations between plasma levels of marine n-3 PUFAs and markers of inflammation were demonstrated.

Altered gut microbiota profile in common variable immunodeficiency associates with levels of lipopolysaccharide and markers of systemic immune activation

Common variable immunodeficiency (CVID) is the most common symptomatic primary immunodeficiency characterized by low immunoglobulin (Ig)G and IgA, and/or IgM. In addition to bacterial infections, a large subgroup has noninfectious inflammatory and autoimmune complications. We performed 16S ribosomal RNA-based profiling of stool samples in 44 CVID patients, 45 patients with inflammatory bowel disease (disease controls), and 263 healthy controls. We measured plasma lipopolysaccharide (LPS) and markers of immune cell activation (i.e., soluble (s) CD14 and sCD25) in an expanded cohort of 104 patients with CVID and in 30 healthy controls. We found a large shift in the microbiota of CVID patients characterized by a reduced within-individual bacterial diversity (alpha diversity, P<0.001) without obvious associations to antibiotics use. Plasma levels of both LPS (P=0.001) and sCD25 (P<0.0001) were elevated in CVID, correlating negatively with alpha diversity and positively with a dysbiosis index calculated from the taxonomic profile. Low alpha diversity and high dysbiosis index, LPS, and immune markers were most pronounced in the subgroup with inflammatory and autoimmune complications. Low level of IgA was associated with decreased alpha diversity, but not independently from sCD25 and LPS. Our findings suggest a link between immunodeficiency, systemic immune activation, LPS, and altered gut microbiota.

Increased Levels of Interferon-Inducible Protein 10 (IP-10) in 22q11.2 Deletion Syndrome

The 22q11.2 deletion syndrome (22q11.2 DS), also known as DiGeorge syndrome, is a genetic disorder with an estimated incidence of 1:4000 births. These patients may suffer from affection of many organ systems with cardiac malformations, thymic hypoplasia or aplasia, hypoparathyroidism, palate anomalies and psychiatric disorders being the most frequent. The incidence of autoimmune diseases is increased in older patients. The aim of the present study was to examine a cytokine profile in patients with 22q11.2 DS by measuring a broad spectrum of serum cytokines. Patients with a proven deletion of chromosome 22q11.2 (n = 55) and healthy individuals (n = 54) recruited from an age- and sex-comparable group were included in the study. Serum levels of 27 cytokines, including chemokines and growth factors, were analysed using multiplex technology. Interferon-inducible protein 10 (IP-10) was also measured by ELISA to confirm the multiplex results. The 22q11.2 DS patients had distinctly and significantly raised levels of pro-inflammatory and angiostatic chemokine IP-10 (P < 0.001) compared to controls. The patients with congenital heart defects (n = 31) had significantly (P = 0.018) raised serum levels of IP-10 compared to patients born without heart defects (n = 24). The other cytokines investigated were either not detectable or did not differ between patients and controls.

Off-pump cardiac surgery abolishes complement activation

Background. This prospective randomized study compared the inflammatory response in patients undergoing elective on-pump and off-pump coronary artery bypass grafting. Patients and methods. Forty-four patients undergoing elective coronary artery bypass grafting were recruited with 22 patients randomized to on-pump heart surgery and 22 patients to off-pump coronary bypass surgery. Plasma levels of C3bc, the terminal SC5b-9 complement complex, myeloperoxidase, β -thromboglobulin and prothrombin fragment F1 + 2 were measured before the operation, intraoperatively, at termination of the operation, and two hours post-operatively. Results. Complement was markedly activated in the on-pump group as indicated by a significant increase in C3bc and SC5b-9 (p < 0.001 for both), whereas no complement activation was seen in the off-pump group (p = 0.001 between the groups). In contrast, both groups showed significant activation of neutrophils, platelets and coagulation, as indicated by an early increase in myeloperoxidase and a post-operative increase in β-thromboglobulin and F1 + 2, respectively. Notably, there were no inter-group differences with regard to neutrophil and platelet activation, whereas coagulation activation was more pronounced in the off-pump group (p < 0.01). Conclusions. Off-pump surgery completely eliminated the heart-lung machine-induced complement activation. Neutrophils and platelets were equally activated in both groups, whereas coagulation was enhanced post-operatively in the off-pump group. Perfusion (2007) 22, 251—256.

Rickettsia conorii is a potent complement activator in vivo and combined inhibition of complement and CD14 is required for attenuation of the cytokine response ex vivo

Mediterranean spotted fever caused by Rickettsia conorii is a potentially lethal disease characterized by vascular inflammation affecting multiple organs. Studies of R. conorii so far have focused on activation of inflammatory cells and their release of inflammatory cytokines, but complement activation has not been investigated in R. conorii-infected patients. Here, we performed a comprehensive analysis of complement activation markers and the soluble cross-talking co-receptor CD14 (sCD14) in plasma from R. conorii-infected patients. The clinical data were supplemented with ex vivo experiments where the cytokine response was characterized in human whole blood stimulated with R. conorii. Complement activation markers at the level of C3 (C3bc, C3bBbP) and terminal pathway activation (sC5b-9), as well as sCD14, were markedly elevated (p <0.01 for all), and closely correlated (p <0.05 for all), in patients at admission compared with healthy matched controls. All tested markers were significantly reduced to baseline values at time of follow up. Rickettsia conorii incubated in human whole blood was shown to trigger complement activation accompanied by release of the inflammatory cytokines interleukin-1β (IL-1β), IL-6, IL-8 and tumour necrosis factor. Whereas inhibition of either C3 or CD14 had only a minor effect on released cytokines, combined inhibition of C3 and CD14 resulted in significant reduction, virtually to baseline levels, of the four cytokines (p <0.05 for all). Our data show that complement is markedly activated upon R. conorii infection and complement activation is, together with CD14, responsible for a major part of the cytokine response induced by R. conorii in human whole blood.

Combined Inhibition of Complement and CD14 Attenuates Bacteria-Induced Inflammation in Human Whole Blood More Efficiently Than Antagonizing the Toll-like Receptor 4-MD2 Complex

Background. Single inhibition of the Toll-like receptor 4 (TLR4)–MD2 complex failed in treatment of sepsis. CD14 is a coreceptor for several TLRs, including TLR4 and TLR2. The aim of this study was to investigate the effect of single TLR4-MD2 inhibition by using eritoran, compared with the effect of CD14 inhibition alone and combined with the C3 complement inhibitor compstatin (Cp40), on the bacteria-induced inflammatory response in human whole blood.

Methods. Cytokines were measured by multiplex technology, and leukocyte activation markers CD11b and CD35 were measured by flow cytometry.

Results. Lipopolysaccharide (LPS)–induced inflammatory markers were efficiently abolished by both anti-CD14 and eritoran. Anti-CD14 was significantly more effective than eritoran in inhibiting LPS-binding to HEK-293E cells transfected with CD14 and Escherichia coli–induced upregulation of monocyte activation markers (P < .01). Combining Cp40 with anti-CD14 was significantly more effective than combining Cp40 with eritoran in reducing E. coli–induced interleukin 6 (P < .05) and monocyte activation markers induced by both E. coli (P < .001) and Staphylococcus aureus (P < .01). Combining CP40 with anti-CD14 was more efficient than eritoran alone for 18 of 20 bacteria-induced inflammatory responses (mean P < .0001).

Conclusions. Whole bacteria–induced inflammation was inhibited more efficiently by anti-CD14 than by eritoran, particularly when combined with complement inhibition. Combined CD14 and complement inhibition may prove a promising treatment strategy for bacterial sepsis.

Effect of Perfusion Fluids on Recovery of Inflammatory Mediators in Microdialysis

Microdialysis is an excellent tool to assess tissue inflammation in patients, but in vitro systems to evaluate recovery of inflammatory mediators have not been standardized. We aimed to develop a reference plasma preparation and evaluate different perfusion fluids with respect to recovery of metabolic and inflammatory markers. The reference preparation was produced by incubation of human blood with lipopolysaccharide and cobra venom factor to generate cytokines and activate complement, respectively. Microdialysis with 100 kDa catheters was performed using different colloid and crystalloid perfusion fluids (hydroxyethyl starch (HES) 130/0.4, HES 200/0.5, hyperosmolar HES 200/0.5, albumin 200 g/l, T1 perfusion fluid and Ringer's acetate) compared to today's recommended dextran 60 solution. Recovery of glucose, glycerol and pyruvate was not significantly different between the perfusion fluids, whereas lactate had lower recovery in HES 200/0.5 and albumin perfusion fluids. Recovery rates for the inflammatory proteins in comparison with the concentration in the reference preparation differed substantially: IL-6 = 9%, IL-1β = 18%, TNF = 0.3%, MCP-1 = 45%, IL-8 = 48%, MIG = 48%, IP-10 = 25%, C3a = 53% and C5a = 12%. IL-10 was not detectable in microdialysis dialysate. HES 130/0.4 and HES 200/0.5 yielded a recovery not significantly different from dextran 60. Hyperosmolar HES 200/0.5 and albumin showed significantly different pattern of recovery with increased concentration of MIG, IP-10, C3a and C5a and decreased concentration of IL-1β, TNF, MCP-1 and IL-8 in comparison with dextran 60. In conclusion, microdialysis perfusion fluid dextran 60 can be replaced by the commonly used HES 130/0.4, whereas albumin might be used if specific immunological variables are in focus. The present reference plasma preparation is suitable for in vitro evaluation of microdialysis systems.

Combined inhibition of complement and CD14 improved outcome in porcine polymicrobial sepsis

Introduction

Sepsis is an exaggerated and dysfunctional immune response to infection. Activation of innate immunity recognition systems including complement and the Toll-like receptor family initiate this disproportionate inflammatory response. The aim of this study was to explore the effect of combined inhibition of the complement component C5 and the Toll-like receptor co-factor CD14 on survival, hemodynamic parameters and systemic inflammation including complement activation in a clinically relevant porcine model of polymicrobial sepsis.

Methods

Norwegian landrace piglets (4 ± 0.5 kg) were blindly randomized to a treatment group (n = 12) receiving the C5 inhibitor coversin (OmCI) and anti-CD14 or to a positive control group (n = 12) receiving saline. Under anesthesia, sepsis was induced by a 2 cm cecal incision and the piglets were monitored in standard intensive care for 8 hours. Three sham piglets had a laparotomy without cecal incision or treatment. Complement activation was measured as sC5b-9 using enzyme immunoassay. Cytokines were measured with multiplex technology.

Results

Combined C5 and CD14 inhibition significantly improved survival (p = 0.03). Nine piglets survived in the treatment group and four in the control group. The treatment group had significantly lower pulmonary artery pressure (p = 0.04) and ratio of pulmonary artery pressure to systemic artery pressure (p < 0.001). Plasma sC5b-9 levels were significantly lower in the treatment group (p < 0.001) and correlated significantly with mortality (p = 0.006). IL-8 and IL-10 were significantly (p < 0.05) lower in the treatment group.

Conclusions

Combined inhibition of C5 and CD14 significantly improved survival, hemodynamic parameters and inflammation in a blinded, randomized trial of porcine polymicrobial sepsis.

Complement activation patterns in atypical haemolytic uraemic syndrome during acute phase and in remission

Atypical haemolytic uraemic syndrome (aHUS) is associated with (genetic) alterations in alternative complement pathway. Nevertheless, comprehensive evidence that the complement system in aHUS patients is more prone to activation is still lacking. Therefore, we performed a thorough analysis of complement activation in acute phase and in remission of this disease. Complement activation patterns of the aHUS patients in acute phase and in remission were compared to those of healthy controls. Background levels of complement activation products C3b/c, C3bBbP and terminal complement complex (TCC) were measured using enzyme-linked immunosorbent assay (ELISA) in ethylenediamine tetraacetic acid (EDTA) plasma. In vitro-triggered complement activation in serum samples was studied using zymosan-coating and pathway-specific assay. Furthermore, efficiencies of the C3b/c, C3bBbP and TCC generation in fluid phase during spontaneous activation were analysed. Patients with acute aHUS showed elevated levels of C3b/c (P < 0·01), C3bBbP (P < 0·0001) and TCC (P < 0·0001) in EDTA plasma, while values of patients in remission were normal, compared to those of healthy controls. Using data from a single aHUS patient with complement factor B mutation we illustrated normalization of complement activation during aHUS recovery. Serum samples from patients in remission showed normal in vitro patterns of complement activation and demonstrated normal kinetics of complement activation in the fluid phase. Our data indicate that while aHUS patients have clearly activated complement in acute phase of the disease, this is not the case in remission of aHUS. This knowledge provides important insight into complement regulation in aHUS and may have an impact on monitoring of these patients, particularly when using complement inhibition therapy.

The key roles of complement and tissue factor in Escherichia coli-induced coagulation in human whole blood

The complement system and the Toll-like (TLR) co-receptor CD14 play important roles in innate immunity and sepsis. Tissue factor (TF) is a key initiating component in intravascular coagulation in sepsis, and long pentraxin 3 (PTX3) enhances the lipopolysaccharide (LPS)-induced transcription of TF. The aim of this study was to study the mechanism by which complement and CD14 affects LPS- and Escherichia coli (E. coli)-induced coagulation in human blood. Fresh whole blood was anti-coagulated with lepirudin, and incubated with ultra-purified LPS (100 ng/ml) or with E. coli (1 × 10(7) /ml). Inhibitors and controls included the C3 blocking peptide compstatin, an anti-CD14 F(ab')2 antibody and a control F(ab')2 . TF mRNA was measured using quantitative polymerase chain reaction (qPCR) and monocyte TF surface expression by flow cytometry. TF functional activity in plasma microparticles was measured using an amidolytic assay. Prothrombin fragment F 1+2 (PTF1.2) and PTX3 were measured by enzyme-linked immunosorbent assay (ELISA). The effect of TF was examined using an anti-TF blocking antibody. E. coli increased plasma PTF1.2 and PTX3 levels markedly. This increase was reduced by 84->99% with compstatin, 55-97% with anti-CD14 and > 99% with combined inhibition (P < 0·05 for all). The combined inhibition was significantly (P < 0·05) more efficient than compstatin and anti-CD14 alone. The LPS- and E. coli-induced TF mRNA levels, monocyte TF surface expression and TF functional activity were reduced by > 99% (P < 0·05) with combined C3 and CD14 inhibition. LPS- and E. coli-induced PTF1.2 was reduced by 76-81% (P < 0·05) with anti-TF antibody. LPS and E. coli activated the coagulation system by a complement- and CD14-dependent up-regulation of TF, leading subsequently to prothrombin activation.

The anti-inflammatory effect of combined complement and CD14 inhibition is preserved during escalating bacterial load

Combined inhibition of complement and CD14 is known to attenuate bacterial-induced inflammation, but the dependency of the bacterial load on this effect is unknown. Thus, we investigated whether the effect of such combined inhibition on Escherichia coli- and Staphylococcus aureus-induced inflammation was preserved during increasing bacterial concentrations. Human whole blood was preincubated with anti-CD14, eculizumab (C5-inhibitor) or compstatin (C3-inhibitor), or combinations thereof. Then heat-inactivated bacteria were added at final concentrations of 5 × 10(4) -1 × 10(8) /ml (E. coli) or 5 × 10(7) -4 × 10(8) /ml (S. aureus). Inflammatory markers were measured using enzyme-linked immunosorbent assay (ELISA), multiplex technology and flow cytometry. Combined inhibition of complement and CD14 significantly (P < 0.05) reduced E. coli-induced interleukin (IL)-6 by 40-92% at all bacterial concentrations. IL-1β, IL-8 and macrophage inflammatory protein (MIP)-1α were significantly (P < 0.05) inhibited by 53-100%, and the effect was lost only at the highest bacterial concentration. Tumour necrosis factor (TNF) and MIP-1β were significantly (P < 0.05) reduced by 80-97% at the lowest bacterial concentration. Monocyte and granulocyte CD11b were significantly (P < 0.05) reduced by 63-91% at all bacterial doses. Lactoferrin was significantly (P < 0.05) attenuated to the level of background activity at the lowest bacterial concentration. Similar effects were observed for S. aureus, but the attenuation was, in general, less pronounced. Compared to E. coli, much higher concentrations of S. aureus were required to induce the same cytokine responses. This study demonstrates generally preserved effects of combined complement and CD14 inhibition on Gram-negative and Gram-positive bacterial-induced inflammation during escalating bacterial load. The implications of these findings for future therapy of sepsis are discussed.

Effect of Cardiac Resynchronization Therapy on Inflammation in Congestive Heart Failure: A Review

Congestive heart failure is associated with increased levels of several inflammatory mediators, and animal studies have shown that infusion of a number of cytokines can induce heart failure. However, several drugs with proven efficacy in heart failure have failed to affect inflammatory mediators, and anti-inflammatory therapy in heart failure patients has thus far been disappointing. Hence, to what extent heart failure is caused by or responsible for the increased inflammatory burden in the patient is still unclear. Over the past couple of decades, resynchronization therapy with a biventricular pacemaker has emerged as an effective treatment in a subset of heart failure patients, reducing both morbidity and mortality. Such treatment has also been shown to affect the inflammation associated with heart failure. In this study, we review recent data on the association between heart failure and inflammation, and in particular how resynchronization therapy can affect the inflammatory process.

The complement system and toll-like receptors as integrated players in the pathophysiology of atherosclerosis

Despite recent medical advances, atherosclerosis is a global burden accounting for numerous deaths and hospital admissions. Immune-mediated inflammation is a major component of the atherosclerotic process, but earlier research focus on adaptive immunity has gradually switched towards the role of innate immunity. The complement system and toll-like receptors (TLRs), and the crosstalk between them, may be of particular interest both with respect to pathogenesis and as therapeutic targets in atherosclerosis. Animal studies indicate that inhibition of C3a and C5a reduces atherosclerosis. In humans modified LDL-cholesterol activate complement and TLRs leading to downstream inflammation, and histopathological studies indicate that the innate immune system is present in atherosclerotic lesions. Moreover, clinical studies have demonstrated that both complement and TLRs are upregulated in atherosclerotic diseases, although interventional trials have this far been disappointing. However, based on recent research showing an intimate interplay between complement and TLRs we propose a model in which combined inhibition of both complement and TLRs may represent a potent anti-inflammatory therapeutic approach to reduce atherosclerosis.