Immunomodulation in sepsis: state of the art and future perspective

Combination of GM CSF and carbapenem is superior to carbapenem monotherapy in difficult-to-treat spontaneous bacterial peritonitis: A randomized controlled trial

BACKGROUND

Patients with cirrhosis and treatment non-responsive spontaneous bacterial peritonitis (SBP) have high mortality. We aimed to investigate whether GM-CSF can improve SBP response rates.

PATIENTS AND METHODS

In this open-label RCT, 131 cirrhosis patients with difficult-to-treat SBP (DTT SBP) were randomized to receive meropenem alone (1 g IV thrice daily for 5 days) (MERO Group, n = 66) or in combination with GM-CSF (1.5 mcg/Kg daily IV till resolution or till 5d) (MEROGM Group, n = 65). The primary end-point was SBP early-response (reduction in absolute neutrophil count (ANC) by >25% after 48 h). Secondary end-points included SBP resolution at day 5.

RESULTS

Patients in MEROGM group in comparison to MERO group had higher SBP early-response (60% vs. 31.8%; p = .001) and SBP resolution rates (55.4% vs. 24.2%; p = .0003). Patients in the combination arm also had better resolution of pneumonia {8/17 (47.05%) vs. 2/19 (10.5%), p = .02} and lower incidence of new-onset AKI (15.4% vs. 31.8%, p = .02), HE (18.5% vs. 34.8%, p = .04) and infections (21.5% vs. 37.9%, p = .05). In comparison to MERO group, 7-day survival was higher in MEROGM group (89.2% vs. 78.7%, p = .03), though the 28-day survival was comparable (78.4% vs. 71.2%; p = .66). None of the patients developed treatment-related severe adverse effects requiring discontinuation of therapy.

CONCLUSIONS

The addition of GM-CSF to meropenem significantly improves response rates in DTT SBP patients within 48 h. Early use of GMCSF modulates host immune response, and enhances antibiotic response with higher SBP resolution. The use of GMCSF needs to be considered in combating difficult SBP in cirrhosis patients.

Hepatic non-parenchymal S100A9-TLR4-mTORC1 axis normalizes diabetic ketogenesis

Unrestrained ketogenesis leads to life-threatening ketoacidosis whose incidence is high in patients with diabetes. While insulin therapy reduces ketogenesis this approach is sub-optimal. Here, we report an insulin-independent pathway able to normalize diabetic ketogenesis. By generating insulin deficient male mice lacking or re-expressing Toll-Like Receptor 4 (TLR4) only in liver or hepatocytes, we demonstrate that hepatic TLR4 in non-parenchymal cells mediates the ketogenesis-suppressing action of S100A9. Mechanistically, S100A9 acts extracellularly to activate the mechanistic target of rapamycin complex 1 (mTORC1) in a TLR4-dependent manner. Accordingly, hepatic-restricted but not hepatocyte-restricted loss of Tuberous Sclerosis Complex 1 (TSC1, an mTORC1 inhibitor) corrects insulin-deficiency-induced hyperketonemia. Therapeutically, recombinant S100A9 administration restrains ketogenesis and improves hyperglycemia without causing hypoglycemia in diabetic mice. Also, circulating S100A9 in patients with ketoacidosis is only marginally increased hence unveiling a window of opportunity to pharmacologically augment S100A9 for preventing unrestrained ketogenesis. In summary, our findings reveal the hepatic S100A9-TLR4-mTORC1 axis in non-parenchymal cells as a promising therapeutic target for restraining diabetic ketogenesis.

Excess ketogenesis can lead to ketoacidosis, a serious complication in patients with diabetes. Here the authors report an insulin independent pathway, the hepatic nonparenchymal S100A9-TLR4-mTORC1 axis, that is able to normalize diabetic ketogenesis and pre-clinical data to suggest potential for development of S100A9 based adjunctive therapy to insulin.

Comparison of Interleukin-6 Plasma Concentration in Multisystem Inflammatory Syndrome in Children Associated With SARS-CoV-2 and Pediatric Sepsis

Importance: Multisystem Inflammatory Syndrome in Children (MIS-C) associated with SARS-CoV-2 infection is thought to be driven by a post-viral dysregulated immune response, where interleukin 6 (IL-6) might have a central role. In this setting, IL-6 inhibitors are prescribed as immunomodulation in cases refractory to standard therapy. Objective: To compare plasma IL-6 concentration between critically ill children with MIS-C and sepsis. Design: A retrospective cohort study from previously collected data. Setting: Individual patient data were gathered from three different international datasets. Participants: Critically ill children between 1 month-old and 18 years old, with an IL-6 level measured within 48 h of admission to intensive care. Septic patients were diagnosed according to Surviving Sepsis Campaign definition and MIS-C cases by CDC criteria. We excluded children with immunodeficiency or immunosuppressive therapy. Exposure: None. Main Outcome(s) and Measure(s): The primary outcome was IL-6 plasma concentration in MIS-C and sepsis group at admission to the intensive care unit. We described demographics, inflammatory biomarkers, and clinical outcomes for both groups. A subgroup analysis for shock in each group was done. Results: We analyzed 66 patients with MIS-C and 44 patients with sepsis. MIS-C cases were older [96 (48, 144) vs. 20 (5, 132) months old, p < 0.01], but no differences in sex (41 vs. 43% female, p = 0.8) compared to septic group. Mechanical ventilation use was 48.5 vs. 93% (p < 0.001), vasoactive drug use 79 vs. 66% (p = 0.13), and mortality 4.6 vs. 34.1% (p < 0.01) in MIS-C group compared to sepsis. IL-6 was 156 (36, 579) ng/dl in MIS-C and 1,432 (122, 6,886) ng/dl in sepsis (p < 0.01), while no significant differences were observed in procalcitonin (PCT) and c-reactive protein (CRP). 52/66 (78.8%) patients had shock in MIS-C group, and 29/44 (65.9%) had septic shock in sepsis group. Septic shock had a significantly higher plasma IL-6 concentration than the three other sub-groups. Differences in IL-6, CRP, and PCT were not statistically different between MIS-C with and without shock. Conclusions and Relevance: IL-6 plasma concentration was elevated in critically ill MIS-C patients but at levels much lower than those of sepsis. Furthermore, IL-6 levels don't discriminate between MIS-C cases with and without shock. These results lead us to question the role of IL-6 in the pathobiology of MIS-C, its diagnosis, clinical outcomes, and, more importantly, the off-label use of IL-6 inhibitors for these cases.

Caspase-8 inhibition represses initial human monocyte activation in septic shock model

In septic patients, the onset of septic shock occurs due to the over-activation of monocytes. We tested the therapeutic potential of directly targeting innate immune cell activation to limit the cytokine storm and downstream phases. We initially investigated whether caspase-8 could be an appropriate target given it has recently been shown to be involved in microglial activation. We found that LPS caused a mild increase in caspase-8 activity and that the caspase-8 inhibitor IETD-fmk partially decreased monocyte activation. Furthermore, caspase-8 inhibition induced necroptotic cell death of activated monocytes. Despite inducing necroptosis, caspase-8 inhibition reduced LPS-induced expression and release of IL-1β and IL-10. Thus, blocking monocyte activation has positive effects on both the pro and anti-inflammatory phases of septic shock. We also found that in primary mouse monocytes, caspase-8 inhibition did not reduce LPS-induced activation or induce necroptosis. On the other hand, broad caspase inhibitors, which have already been shown to improve survival in mouse models of sepsis, achieved both. Thus, given that monocyte activation can be regulated in humans via the inhibition of a single caspase, we propose that the therapeutic use of caspase-8 inhibitors could represent a more selective alternative that blocks both phases of septic shock at the source.

Granulocyte and monocyte adsorptive apheresis ameliorates sepsis in rats

Background

Overwhelming activation of granulocytes and monocytes is central to inflammatory responses during sepsis. Granulocyte and monocyte adsorptive apheresis (GMA) is an extracorporeal leukocyte apheresis device filled with cellulose acetate beads and selectively adsorbs granulocytes and monocytes from the peripheral blood.

Methods

In this study, septic rats received the GMA treatment for 2 h at 18 h after cecal ligation and puncture.

Results

GMA selectively adsorbed activated neutrophils and monocytes from the peripheral blood, reduced serum inflammatory cytokine expression, and seemed to improve organ injuries and animal survival. GMA potentially reduced lung injury by alleviating the infiltration of inflammatory cells and the secretion of cytokines.

Conclusions

This study showed that selective granulocyte and monocyte adsorption with cellulose acetate beads might ameliorate cecal ligation and puncture (CLP)-induced sepsis and improve survival and organ function.

Neutrophil derived microparticles increase mortality and the counter-inflammatory response in a murine model of sepsis

Although advances in medical care have significantly improved sepsis survival, sepsis remains the leading cause of death in the ICU. This is likely due to a lack of complete understanding of the pathophysiologic mechanisms that lead to dysfunctional immunity. Neutrophil derived microparticles (NDMPs) have been shown to be the predominant microparticle present at infectious and inflamed foci in human models, however their effect on the immune response to inflammation and infection is sepsis has not been fully elucidated. As NDMPs may be a potential diagnostic and therapeutic target, we sought to determine the impact NDMPs on the immune response to a murine polymicrobial sepsis. We found that peritoneal neutrophil numbers, bacterial loads, and NDMPs were increased in our abdominal sepsis model. When NDMPs were injected into septic mice, we observed increased bacterial load, decreased neutrophil recruitment, increased expression of IL-10 and worsened mortality. Furthermore, the NDMPs express phosphatidylserine and are ingested by F4/80 macrophages via a Tim-4 and MFG-E8 dependent mechanism. Finally, upon treatment, NDMPs decrease macrophage activation, increase IL-10 release and decrease macrophage numbers. Altogether, these data suggest that NDMPs enhance immune dysfunction in sepsis by blunting the function of neutrophils and macrophages, two key cell populations involved in the early immune response to infection. This article is part of a Special Issue entitled: Immune and Metabolic Alterations in Trauma and Sepsis edited by Dr. Raghavan Raju.

Differential Effects of Vitamins A and D on the Transcriptional Landscape of Human Monocytes during Infection

Vitamin A and vitamin D are essential nutrients with a wide range of pleiotropic effects in humans. Beyond their well-documented roles in cellular differentiation, embryogenesis, tissue maintenance and bone/calcium homeostasis, both vitamins have attracted considerable attention due to their association with-immunological traits. Nevertheless, our knowledge of their immunomodulatory potential during infection is restricted to single gene-centric studies, which do not reflect the complexity of immune processes. In the present study, we performed a comprehensive RNA-seq-based approach to define the whole immunomodulatory role of vitamins A and D during infection. Using human monocytes as host cells, we characterized the differential role of both vitamins upon infection with three different pathogens: Aspergillus fumigatus, Candida albicans and Escherichia coli. Both vitamins showed an unexpected ability to counteract the pathogen-induced transcriptional responses. Upon infection, we identified 346 and 176 immune-relevant genes that were regulated by atRA and vitD, respectively. This immunomodulatory activity was dependent on the inflammatory stimulus, allowing us to distinguish regulatory patterns which were specific for each stimulatory setting. Moreover, we explored possible direct and indirect mechanisms of vitamin-mediated regulation of the immune response. Our findings highlight the importance of vitamin-monitoring in critically ill patients. Moreover, our results underpin the potential of atRA and vitD as therapeutic options for anti-inflammatory treatment.

OXYGEN MITIGATES THE INFLAMMATORY RESPONSE IN A MODEL OF HEMORRHAGE AND ZYMOSAN-INDUCED INFLAMMATION

Sequential insults (hits) may change the inflammatory reaction that develops in response to separate single hits (e.g., injury, infection); however, their effects on the long-term clinical outcome are still only partially elucidated. Double-hit models are typically severe and fatal. We characterized in C57BL/6 mice a moderate double-hit model of hemorrhage (35%-40% of total blood volume) and resuscitation, followed by peritoneal injection of zymosan A that induced local and systemic inflammation with 58% mortality. This model allowed exploration of the inflammatory response over time in the surviving mice. We show that after 2 days, mice subjected to the double-hit model had elevated proinflammatory systemic and local peritoneal cytokine response (interleukin [IL]-1β, tumor necrosis factor-α, IL-6) and moderately elevated anti-inflammatory cytokines (IL-10, transforming growth factor-β), compared with the single-hit and sham mice. However, this dynamically changed, and by day 7, proinflammatory cytokines were reduced, and anti-inflammatory cytokines were markedly (P < 0.05) elevated in the double-hit group. Mice in the double-hit group that inhaled 100% oxygen intermittently for 6 h every day exhibited markedly reduced serum proinflammatory cytokines as early as day 2 (P < 0.05), inhibited macrophage infiltration into the peritoneum (by 13-fold; P < 0.05), and substantially increased survival rates of 85% (P = 0.00144). Oxygen mitigates the inflammatory response and exerts a beneficial effect on survival in a double-hit model of hemorrhage and zymosan-induced inflammation.

Role of HMGB1 translocation to neuronal nucleus in rat model with septic brain injury

High-mobility Group Box-1 (HMGB1) is a central late proinflammatory cytokine that triggers the inflammatory response during sepsis. However, whether HMGB1 is involved in the pathogenesis of septic brain damage is unknown. In this study, we investigated the role of HMGB1 in regulating brain injury in a rat model of sepsis. Wistar rats were subjected to cecal ligation and puncture (CLP) to induce septic brain injury. Hematoxylin and eosin staining was used to detect pathological changes in the cortex. The cellular localization of HMGB1 was determined using immunostaining. Cortical levels of HMGB1, its receptor for advanced glycation end-products (RAGE), and downstream effecter, nuclear factor kappa-B (NF-κB) subunit p65, were detected via western blot.HMGB1was increased in the cytoplasm via translocation from the nucleus predominantly in neurons. Moreover, RAGE and NF-κB p65 were upregulated after septic brain injury. Ethyl pyruvate, an inhibitor of HMGB1, down-regulated the expression of RAGE and NF-κB p65via inhibiting HMGB1 expression in the cytoplasm. Collectively, our findings suggest that HMGB1 and its signaling transduction have critical roles in the pathogenesis of septic brain injury. HMGB1 inhibition might be a potential new therapeutic target for septic brain injury.

Ulinastatin and/or thymosin α1 for severe sepsis: A systematic review and meta-analysis

OBJECTIVE

Ulinastatin (UTI) and thymosin α1 (Tα1) have been investigated for their immunoregulatory properties in patients with severe sepsis. However, it is unclear whether immunomodulatory therapy using UTI combined with Tα1 (UCT), UTI alone (UA), or Tα1 alone (TA) improves the disease outcome. The objective of this study was to analyze the effectiveness of UCT, UA, and TA for the treatment of severe sepsis.

METHODS

PubMed, EMBASE, and Cochrane Library databases were investigated from inception to September 2015. Randomized controlled trials (RCTs) examining the treatment of patients with severe sepsis by UCT, UA, and TA were defined as eligible. Data were analyzed using Review Manager 5.3, and the RCTs were evaluated by the Cochrane Handbook 5.1.0. The quality of the evidence was evaluated according to the Grading of Recommendations, Assessment, Development, and Evaluations (GRADE).

RESULTS

Ten articles and 12 studies were included in this systematic review and meta-analysis. The primary outcome measures indicated that UCT was associated with significantly lower 28-day mortality (risk ratio [RR], 0.67; 95% confidence interval [CI], 0.57-0.80; p < 0.00001; n = 915; GRADE rating, moderate) and 90-day mortality (RR, 0.75; 95% CI, 0.61-0.93; p = 0.009; n = 547; GRADE rating, moderate); UA was associated with no significant difference in the 28-day mortality (RR, 0.60; 95% CI, 0.30-1.20; p = 0.15; n = 182; GRADE rating, low), and there was no report on 90-day mortality; TA was associated with significantly lower 28-day mortality (RR, 0.72; 95% CI, 0.55-0.93; p = 0.01; n = 494; GRADE rating, low), but there was no significant difference in the 90-day mortality (RR, 0.84; 95% CI, 0.54-1.31; p = 0.45; n = 91; GRADE rating, very low). In the secondary outcome measures, there was obvious heterogeneity in the length of the intensive care unit stay and that of the mechanical ventilation, length of the antibiotics and vasopressor use, and 28-day Acute Physiology and Chronic Health Evaluation II (APACHE II) scores.

CONCLUSION

Treatment of severe sepsis with UCT reduced both the 28-day and the 90-day mortality, whereas treatment with TA reduced only the 28-day mortality. The effects of UCT, UA, and TA on intensive care unit stay, mechanical ventilation, antibiotics and vasopressor use, and 28-day APACHE II scores of septic patients are still unclear. Additional high-quality RCTs are needed to define clearly the guidelines for the treatment of severe sepsis.

LEVEL OF EVIDENCE

Systematic review, level IV.

Impact of caspase-8 and PKA in regulating neutrophil-derived microparticle generation

The morbidity and mortality from sepsis continues to remain high despite extensive research into understanding this complex immunologic process. Further, while source control and antibiotic therapy have improved patient outcomes, many immunologically based therapies have fallen short. Microparticles (MPs) are intact vesicles that serve as mediators of intercellular communication as well as markers of inflammation in various disease processes. We have previously demonstrated that MPs can be produced at the infected foci during sepsis, are predominantly of neutrophil derivation (NDMPs) and can modulate immune cells. In this study, we sought to elucidate the molecular mechanisms underlying NDMP generation. Using thioglycolate (TGA) to recruit and activate neutrophils, we first determined that intra-peritoneal TGA increase NDMP accumulation. We next utilized TGA-elicited neutrophils in vitro to investigate signaling intermediates involved in NDMP production, including the intrinsic and extrinsic caspase pathways, cAMP dependent PKA and Epac activation as well as the role myosin light chain kinase (MLCK) as a final mediator of NDMP release. We observed that NDMP generation was dependent on the extrinsic caspase apoptotic pathway (caspase 3 and caspase 8), cAMP activation of PKA but not of Epac, and on activation of MLCK. Altogether, these data contribute to an overall framework depicting the molecular mechanisms that regulate NDMP generation.

Neutrophil derived microvesicles: emerging role of a key mediator to the immune response

In response to infection and trauma, exquisite control of the innate inflammatory response is necessary to promote an anti-microbial response and minimize tissue injury. Over the course of the host response, activated leukocytes are essential for the initial response and can later become unresponsive or undergo apoptosis. Leukocytes, along the continuum of activation to apoptosis, have been shown to generate microvesicles. These vesicles can range in size from 0.1 to 1.0 μm and can retain proteins, RNA and DNA of their parent cells. Importantly, neutrophil-derived microvesicles (NDMV) are robustly increased under inflammatory conditions. The aim of this review is to summarize the research to date upon NDMVs. This will include describing under which disease states NDMVs are increased, mechanisms underlying formation, and the impact of these vesicles upon cellular targets. Altogether, increased awareness of NDMVs during the host innate response may allow for diagnostic tools as well as potential novel therapies during infection and trauma.

Evaluating the efficacy and safety of two doses of the polyclonal anti-tumor necrosis factor-α fragment antibody AZD9773 in adult patients with severe sepsis and/or septic shock: randomized, double-blind, placebo-controlled phase IIb study*

OBJECTIVE

This trial compared the efficacy/safety of two IV doses of AZD9773, a polyclonal antibody to tumor necrosis factor-α, in adult patients with severe sepsis/septic shock.

DESIGN

Multicenter, randomized, double-blind, placebo-controlled phase IIb trial.

SETTING

ICUs in seven countries (Australia, Belgium, Canada, Czech Republic, Finland, France, and Spain).

PATIENTS

Patients 18 years old or older with severe sepsis and/or septic shock. Patients were required to have 1) objective clinical evidence of infection; 2) at least two of four systemic inflammatory response syndrome criteria; and 3) cardiovascular and/or respiratory sepsis-related failure.

INTERVENTIONS

Patients were randomized 1:1:1 to a single loading infusion of AZD9773 250 U/kg followed by 50 U/kg every 12 hours (low dose, n = 100), a single loading infusion of AZD9773 500 U/kg followed by 100 U/kg every 12 hours (high dose, n = 100), or placebo (n = 100) for 5 days. Follow-up assessments were performed up to day 90.

MEASUREMENTS AND MAIN RESULTS

Mean number of ventilator-free days (primary endpoint) did not differ between low-dose (19.7 d) or high-dose AZD9773 (17.3 d) and placebo (18.3 d) (one-sided p = 0.18 and 0.74, respectively). Mortality rates were comparable across treatment groups; relative risk of death versus placebo at day 29 was 0.80 for low-dose AZD9773 (one-sided p = 0.25) and 1.64 for high-dose AZD9773 (p = 0.97). Most patients experienced at least one treatment-emergent adverse event (87.8% in AZD9773-treated patients, 92.9% in placebo patients) although most were mild/moderate in nature. No differences in the incidence of adverse events or laboratory or vital sign abnormalities were observed between groups.

CONCLUSIONS

AZD9773 rapidly and efficiently decreased plasma tumor necrosis factor-α concentration in patients with severe sepsis/septic shock, but this effect did not translate into clinical benefit.

Intravenous administration of ulinastatin (human urinary trypsin inhibitor) in severe sepsis: a multicenter randomized controlled study

Purpose

Ulinastatin, a serine protease inhibitor, inhibits several pro-inflammatory proteases and decreases inflammatory cytokine levels and mortality in experimental sepsis. We studied the effect of ulinastatin on 28-day all-cause mortality in a double-blind trial in patients with severe sepsis in seven Indian hospitals.

Methods

Patients with sepsis were randomized within 48 h of onset of one or more organ failures to receive intravenous administration of ulinastatin (200,000 IU) or placebo 12 hourly for 5 days.

Results

Of 122 randomized subjects, 114 completed the study (55 receiving ulinastatin, 59 receiving placebo). At baseline, the mean APACHE II score was 13.4 (SD = 4.4), 48 (42 %) patients were receiving mechanical ventilation, 58 (51 %) were on vasopressors, and 35 % had multiple organ failure. In the modified intention-to-treat analysis (patients receiving six or more doses of study drugs), 28-day all-cause mortality was 7.3 % with ulinastatin (4 deaths) versus 20.3 % (12 deaths) with placebo (p = 0.045). On multivariate analysis too, treatment with ulinastatin (odds ratio 0.26, 95 % CI 0.07–0.95; p = 0.042) independently decreased 28-day all-cause mortality. However, the mortality difference did not reach statistical significance in the intention-to-treat analysis [10.2 % (6/59 deaths) with ulinastatin versus 20.6 % (13/63 deaths) in the placebo group; p = 0.11]. The ulinastatin group had lower incidence of new-onset organ failure (10 vs. 26 patients, p = 0.003), more ventilator-free days (mean ± SD 19.4 ± 10.6 days vs. 10.2 ± 12.5 days, p = 0.019), and shorter hospital stay (11.8 ± 7.1 days vs. 24.2 ± 7.2 days, p < 0.001).

Conclusions

In this pilot study, intravenous administration of ulinastatin reduced mortality in patients with severe sepsis in the modified intention-to-treat analysis, but not in the intention-to-treat analysis.

Electronic supplementary material

The online version of this article (doi:10.1007/s00134-014-3278-8) contains supplementary material, which is available to authorized users.

Mechanisms underlying mouse TNF-α stimulated neutrophil derived microparticle generation

Despite advances in understanding and treatment of sepsis, it remains a disease with high mortality. Neutrophil Derived Microparticles (NDMPs) are present during sepsis and can modulate the immune system. As TNF-α is a cytokine that predominates in the initial stages of sepsis, we evaluated whether and how TNF-α can induce NDMPs in mice. We observed that TNF-α treatment results in increased NDMP numbers. We also determined that the activation of either TNF receptor 1 (TNFr1) or TNF receptor 2 (TNFr2) resulted in increased NDMP numbers and that activation of both resulted in an additive increase. Inhibition of Caspase 8 diminishes NDMPs generated through TNFr1 activation and inhibition of NF-κB abrogates NDMPs generated through activation of both TNFr1 and TNFr2. We conclude that the early production of TNF-α during sepsis can increase NDMP numbers through activation of the Caspase 8 pathway or NF-κB.

Evaluation of the modified MEDS, MEWS score and Charlson comorbidity index in patients with community acquired sepsis in the emergency department

Sepsis is one of the most important causes of morbidity and mortality in patients presenting to the emergency department. SIRS criteria that define sepsis are not specific and do not reflect the severity of infection. We aimed to evaluate the ability of the modified mortality in emergency department sepsis (MEDS) score, the modified early warning score (MEWS) and the Charlson comorbidity index (CCI) to predict prognosis in patients who are diagnosed in sepsis. We prospectively investigated the value of the CCI, MEWS and modified MEDS Score in the prediction of 28-day mortality in patients presenting to the emergency department who were diagnosed with sepsis. 230 patients were enrolled in the study. In these patients, the 5-day mortality was 17 % (n = 40) and the 28-day mortality was 32.2 % (n = 74). A significant difference was found between surviving patients and those who died in terms of their modified MEDS, MEWS and Charlson scores for both 5-day mortality (p < 0.001, p = 0.013 and p = 0.006, respectively) and 28-day mortality (p < 0.001, p = 0.008 and p < 0.001, respectively). The area under the curve (AUC) for the modified MEDS score in terms of 28-day mortality was 0.77. The MEDS score had a greater prognostic value compared to the MEWS and CCI scores. The performance of modified MEDS score was better than that of other scoring systems, in our study. Therefore, we believe that the modified MEDS score can be reliably used for the prediction of mortality in sepsis.

Human macrophage and dendritic cell-specific silencing of high-mobility group protein B1 ameliorates sepsis in a humanized mouse model

Hypersecretion of cytokines by innate immune cells is thought to initiate multiple organ failure in murine models of sepsis. Whether human cytokine storm also plays a similar role is not clear. Here, we show that human hematopoietic cells are required to induce sepsis-induced mortality following cecal ligation and puncture (CLP) in the severely immunodeficient nonobese diabetic (NOD)/SCID/IL2Rγ(-/-) mice, and siRNA treatment to inhibit HMGB1 release by human macrophages and dendritic cells dramatically reduces sepsis-induced mortality. Following CLP, compared with immunocompetent WT mice, NOD/SCID/IL2Rγ(-/-) mice did not show high levels of serum HMGB1 or murine proinflammatory cytokines and were relatively resistant to sepsis-induced mortality. In contrast, NOD/SCID/IL2Rγ(-/-) mice transplanted with human hematopoietic stem cells [humanized bone marrow liver thymic mice (BLT) mice] showed high serum levels of HMGB1, as well as multiple human but not murine proinflammatory cytokines, and died uniformly, suggesting human cytokines are sufficient to induce organ failure in this model. Moreover, targeted delivery of HMGB1 siRNA to human macrophages and dendritic cells using a short acetylcholine receptor (AchR)-binding peptide [rabies virus glycoprotein (RVG)-9R] effectively suppressed secretion of HMGB1, reduced the human cytokine storm, human lymphocyte apoptosis, and rescued humanized mice from CLP-induced mortality. siRNA treatment was also effective when started after the appearance of sepsis symptoms. These results show that CLP in humanized mice provides a model to study human sepsis, HMGB1 siRNA might provide a treatment strategy for human sepsis, and RVG-9R provides a tool to deliver siRNA to human macrophages and dendritic cells that could potentially be used to suppress a variety of human inflammatory diseases.

Population pharmacokinetic/pharmacodynamic modelling of the anti-TNF-α polyclonal fragment antibody AZD9773 in patients with severe sepsis

AZD9773 is an ovine-derived, polyclonal, anti-tumour necrosis factor-alpha (TNF-α) antibody fragment. Using data from an AZD9773 Phase IIa study in patients with severe sepsis (clinicaltrials.gov: NCT00615017), a population pharmacokinetic/pharmacodynamic (PK/PD) model was developed. The model assessed the influence of various covariates on the PK of AZD9773 and the relationship between AZD9773 exposure and serological TNF-α concentration. A linear two-compartment model was used to describe AZD9773 concentration-time data. A stepwise covariate analysis was performed on the PK parameters. Subsequently, the serological TNF-α concentrations and drug effect were captured using an indirect response model, with a variable production rate of TNF-α described by a quadratic function. Creatinine clearance (CrCL) was the only covariate with a significant effect on the PK of AZD9773. A typical patient's drug clearance varied with CrCL; the relationship was non-linear. Diagnostic analysis of the PK/PD model showed that the fit was good, both across cohorts and in AZD9773-treated versus placebo patients. Serological TNF-α concentrations and the reduction of measurable serum TNF-α by AZD9773 were well characterized across all the cohorts evaluated in the Phase IIa study. This population PK/PD model was subsequently used to simulate alternative dosing options for a Phase IIb study (clinicaltrials.gov: NCT01145560).

A placebo-controlled, double-blind, dose-escalation study to assess the safety, tolerability and pharmacokinetics/pharmacodynamics of single and multiple intravenous infusions of AZD9773 in patients with severe sepsis and septic shock

Introduction

Tumor necrosis factor-alpha (TNF-α), an early mediator in the systemic inflammatory response to infection, is a potential therapeutic target in sepsis. The primary objective of this study was to determine the safety and tolerability of AZD9773, an ovine, polyclonal, anti-human TNF-α Fab preparation, in patients with severe sepsis. Secondary outcomes related to pharmacokinetic (PK) and pharmacodynamic (PD) parameters.

Methods

In this double-blind, placebo-controlled, multicenter Phase IIa study, patients were sequentially enrolled into five escalating-dose cohorts (single doses of 50 or 250 units/kg; multiple doses of 250 units/kg loading and 50 units/kg maintenance, 500 units/kg loading and 100 units/kg maintenance, or 750 units/kg loading and 250 units/kg maintenance). In each cohort, patients were randomized 2:1 to receive AZD9773 or placebo.

Results

Seventy patients received AZD9773 (n = 47) or placebo (n = 23). Baseline characteristics were similar across cohorts. Mean baseline APACHE score was 25.9. PK data demonstrated an approximately proportional increase in concentration with increasing dose and a terminal half-life of 20 hours. For the multiple-dose cohorts, serum TNF-α concentrations decreased to near-undetectable levels within two hours of commencing AZD9773 infusion. This suppression was maintained in most patients for the duration of treatment. AZD9773 was well tolerated. Most adverse events were of mild-to-moderate intensity and considered by the reporting investigator as unrelated to study treatment.

Conclusions

The safety, PK and PD data support the continued evaluation of AZD9773 in larger Phase IIb/III studies.

Systemic inflammation in the elderly

Inflammation is an adaptive response to surgery. When the pro-inflammatory responses are unregulated and become over reactive, systemic inflammatory response syndrome may occur. Postoperative systemic inflammation is more common than is generally acknowledged and is observed in about 10-15% of elderly patients undergoing major surgery. Although the vast majority of systemic inflammation is related to infections, other important predisposing risk factors, such as extent of trauma and haemorrhage, should not be overlooked. Increased awareness, modification of risk factors and early recognition are the key elements in the management of systemic inflammation. Prompt resuscitation aiming to correct hypotension, hypovolaemia and tissue hypoxia may improve outcome. Future large prospective observational studies are needed to define the incidence, risk factors and impact of systemic inflammatory syndrome in the elderly surgical patients. A better understanding of the molecular events during the systemic inflammatory response syndrome is required for future development of specific immunotherapy.