Risk of death does not alter the efficacy of hydrocortisone therapy in a mouse E. coli pneumonia model: risk and corticosteroids in sepsis

Glucocorticoid therapy in respiratory illness: bench to bedside

Each year, hundreds of millions of individuals are affected by respiratory disease leading to approximately 4 million deaths. Most respiratory pathologies involve substantially dysregulated immune processes that either fail to resolve the underlying process or actively exacerbate the disease. Therefore, clinicians have long considered immune-modulating corticosteroids (CSs), particularly glucocorticoids (GCs), as a critical tool for management of a wide spectrum of respiratory conditions. However, the complex interplay between effectiveness, risks and side effects can lead to different results, depending on the disease in consideration. In this comprehensive review, we present a summary of the bench and the bedside evidence regarding GC treatment in a spectrum of respiratory illnesses. We first describe here the experimental evidence of GC effects in the distal airways and/or parenchyma, both in vitro and in disease-specific animal studies, then we evaluate the recent clinical evidence regarding GC treatment in over 20 respiratory pathologies. Overall, CS remain a critical tool in the management of respiratory illness, but their benefits are dependent on the underlying pathology and should be weighed against patient-specific risks.

Effects of Glucocorticoid Therapy on Sepsis Depend Both on the Dose of Steroids and on the Severity and Phase of the Animal Sepsis Model

Steroids are currently being used in sepsis, particularly in septic shock. However, clinical trials to date have shown contradictory results. This could be attributed to the different patient endotypes and steroid doses, which have also contributed to the inconclusive results. We investigated the effects of glucocorticoid therapy on sepsis in a polymicrobial sepsis model in a variety of settings, such as steroid dose, severity, and sepsis phase. We used a rat model of fecal slurry polymicrobial sepsis. First, we investigated the optimum dose of steroids in a sepsis model. We administered different doses of dexamethasone after sepsis induction (0.1DEX; 0.1 mg/kg, 0.2DEX; 0.2 mg/kg, 5DEX; 5 mg/kg). Second, we used two different severities of the fecal slurry polymicrobial sepsis rat model to examine the effects of the steroids. A moderate or severe model was defined as a survival rate of approximately 70% and 30%, respectively. Third, we administered steroids in an early (1 h after sepsis induction) or late phase (25 h after sepsis). In all the experiments, we investigated the survival rates. In the determined optimal model and settings, we measured serum lactate, alanine transferase (ALT), creatinine, tumor necrosis factor-α (TNF-α), interleukin (IL)-6, IL-10, and arterial blood gas. We evaluated the bacterial burden in the blood and spleen. Endotoxin tolerance of peripheral blood mononuclear cells (PBMCs) and splenocytes was also investigated to determine the level of immune suppression 24 h after sepsis by measuring TNF-α production after stimulation with lipopolysaccharide (LPS) in an ex vivo model. Early treatment of 0.2 mg/kg dexamethasone in a severe sepsis model showed the best beneficial effects. In moderate- or late-phase sepsis, there was no survival gain with steroid treatment. DEX0.2 group showed less acute kidney injury manifested by serum creatinine and blood urea nitrogen. DEX decreased the levels of cytokines, including IL-6, IL-10, and TNF-α. Colony-forming units were significantly decreased in the blood when administered with dexamethasone. Endotoxin tolerance was not significantly different between the DEX0.2 and control groups. In conclusion, early treatment of 0.2 mg/kg dexamethasone improved the outcomes of rats in a severe sepsis model.

Diet-Induced Obesity Mice Execute Pulmonary Cell Apoptosis via Death Receptor and ER-Stress Pathways after E. coli Infection

Obesity has developed into a considerable health problem in the whole world. Escherichia coli (E. coli) can cause nosocomial pneumonia and induce cell apoptosis during injury and infection. Normal (lean) and diet-induced obesity mice (DIO, fed with high-fat diet) were chosen to perform nasal instillation with E. coli to establish a nonfatal acute pneumonia model. At 0 h, 12 h, 24 h, and 72 h postinfection, lung tissues were obtained to measure cell apoptosis. As shown in this study, both lean and DIO mice exhibited histopathological lesions of acute pneumonia and increased cell apoptosis in the lung infected with E. coli. Interestingly, the relative mRNA and protein expressions associated with either endoplasmic reticulum stress or death receptor apoptotic pathway were all dramatically increased in the DIO mice after infection, while only significant upregulation of death receptor apoptotic pathway in the lean mice at 72 h. These results indicated that the DIO mice executed excess cell apoptosis in the nonfatal acute pneumonia induced by E. coli infection through endoplasmic reticulum stress and death receptor apoptotic pathway.

General Adaptation in Critical Illness: Glucocorticoid Receptor-alpha Master Regulator of Homeostatic Corrections

In critical illness, homeostatic corrections representing the culmination of hundreds of millions of years of evolution, are modulated by the activated glucocorticoid receptor alpha (GRα) and are associated with an enormous bioenergetic and metabolic cost. Appreciation of how homeostatic corrections work and how they evolved provides a conceptual framework to understand the complex pathobiology of critical illness. Emerging literature place the activated GRα at the center of all phases of disease development and resolution, including activation and re-enforcement of innate immunity, downregulation of pro-inflammatory transcription factors, and restoration of anatomy and function. By the time critically ill patients necessitate vital organ support for survival, they have reached near exhaustion or exhaustion of neuroendocrine homeostatic compensation, cell bio-energetic and adaptation functions, and reserves of vital micronutrients. We review how critical illness-related corticosteroid insufficiency, mitochondrial dysfunction/damage, and hypovitaminosis collectively interact to accelerate an anti-homeostatic active process of natural selection. Importantly, the allostatic overload imposed by these homeostatic corrections impacts negatively on both acute and long-term morbidity and mortality. Since the bioenergetic and metabolic reserves to support homeostatic corrections are time-limited, early interventions should be directed at increasing GRα and mitochondria number and function. Present understanding of the activated GC-GRα's role in immunomodulation and disease resolution should be taken into account when re-evaluating how to administer glucocorticoid treatment and co-interventions to improve cellular responsiveness. The activated GRα interdependence with functional mitochondria and three vitamin reserves (B1, C, and D) provides a rationale for co-interventions that include prolonged glucocorticoid treatment in association with rapid correction of hypovitaminosis.

Nonantibiotic Adjunctive Therapies for Community-Acquired Pneumonia (Corticosteroids and Beyond): Where Are We with Them?

Community-acquired pneumonia (CAP) is a leading cause of hospitalization, morbidity, and mortality. Despite advances in antibiotic treatments, mortality among patients with CAP is still high. For this reason, interest has been focused on nonantibiotic therapeutic measures directed to the host response rather than the microorganism. The development of an efficacious adjunctive treatment has important implications for reducing mortality in CAP. Some clinical studies performed in the last decade have shown a clinically beneficial effect of corticosteroids, possibly by diminishing local and systemic inflammatory host response. Recent meta-analyses showed faster resolution of symptoms, shorter time to clinically stability, reduction of mechanical ventilation needed, and reduction of mortality in the most severe population, although some methodological limitations must be taken into account. In addition, some studies using statins also suggested improved outcomes due to its anti-inflammatory effect in CAP, although this requires further research. Other adjunctive therapies such as immunoglobulins and stem cells are being explored, but are not yet in the stage of clinical trials. In summary, the use of corticosteroids and other adjuvant treatments are promising in CAP, but more studies are needed to determine their impact on mortality.

Is prolonged low-dose glucocorticoid treatment beneficial in community-acquired pneumonia?

Community-acquired pneumonia (CAP) has a significant impact on public health in terms of short-term and long-term morbidity and mortality. Irrespective of microbiological etiology, the host's inability to fully downregulate systemic inflammation is the dominant pathogenetic process contributing to acute and long-term morbidity and mortality in CAP. Glucocorticoids are the natural regulators of inflammation, and their production increases during infection. There is consistent evidence that downregulation of systemic inflammation with prolonged low-dose glucocorticoid treatment in patients with severe sepsis and acute respiratory distress syndrome improves cardiovascular and pulmonary organ physiology. A recent meta-analysis of pooled controlled small trials (n = 970) of patients admitted with CAP found improved short-term mortality in the subgroup with severe CAP and/or receiving >5 days of glucocorticoid treatment. We have expanded on this meta-analysis by including patients with CAP recruited in trials investigating prolonged low-dose glucocorticoid treatment in septic shock and/or early acute respiratory distress syndrome (n = 1,206). Our findings confirm a survival advantage for severe CAP (RR 0.66, 95% confidence interval 0.51-0.84; p = .001). A large randomized trial is in progress to confirm the aggregate findings of these small trials and to evaluate the long-term effect of this low-cost treatment.

Adjuvant steroid therapy in community-acquired pneumonia: a systematic review and meta-analysis

BACKGROUND

Community-acquired pneumonia (CAP) is a leading cause of morbidity and mortality among adults. Although steroids appear to be beneficial in animal models of CAP, clinical trial data in humans are either equivocal or conflicting.

PURPOSE

Our purpose was to perform a systematic review and meta-analysis of studies examining the impact of steroid therapy on clinical outcomes among adults admitted with CAP.

DATA SOURCES AND STUDY SELECTION

We identified randomized controlled trials (RCTs) through a systematic search of published literature up to July 2011.

DATA EXTRACTION

We estimated relative risks (RR) and weighted mean differences, pooled from each study using a random effects model.

DATA SYNTHESIS

Eight RCTs, comprising 1119 patients, met our selection criteria. Overall quality of the studies was moderate. Adjunctive steroid therapy had no effect on hospital mortality or length of stay in the intensive care unit, but reduced the overall length of hospital stay (RR: -1.21 days [95% confidence interval (CI): -2.12 to -0.29]). Less robust data also demonstrated reduced incidence of delayed shock (RR: 0.12 [95% CI: 0.03 to 0.41]) and reduced persistence of chest x-ray abnormalities (RR: 0.13 [95% CI: 0.06 to 0.27]). A priori subgroup and sensitivity analyses did not alter these findings.

CONCLUSIONS

Moderate-quality evidence suggests that adjunctive steroid therapy for adults hospitalized with CAP reduced the length of hospital stay but did not alter mortality.

Beneficial effects of stress-dose corticosteroid therapy in canines depend on the severity of staphylococcal pneumonia

PURPOSE

The effects of stress-dose corticosteroid therapy were studied in a canine staphylococcal pneumonia model of septic shock.

METHODS

Immediately following intrabronchial bacterial challenge, purpose-bred beagles were treated with stress doses of desoxycorticosterone (DOC), a mineralocorticoid agonist, and dexamethasone (DEX), a glucocorticoid agonist, or with placebo for 96 h. Oxacillin (30 mg/kg every 8 h) was started 4 h after infection onset. Bacterial dose was titrated to achieve 80-90 % lethality (n = 20) using an adaptive design; additional animals (n = 18) were investigated using the highest bacterial dose.

RESULTS

Initial analysis of all animals (n = 38) demonstrated that the effects of DOC + DEX were significantly altered by bacterial dose (p = 0.04). The treatment effects of DOC + DEX were different in animals administered high or relatively lower bacterial doses in terms of survival (p = 0.05), shock reversal (p = 0.02), interleukin-6 levels (p = 0.02), and temperature (p = 0.01). DOC + DEX significantly improved the above parameters (p ≤ 0.03 for all) and lung injury scores (p = 0.02) after high-dose bacterial challenges, but not after lower challenges (p = not significant for all). Oxacillin trough levels were below the minimum inhibitory concentration of the infecting organism, and DOC + DEX increased the frequency of persistent staphylococcal bacteremia (odds ratio 3.09; 95 % confidence interval 1.05-9.11; p = 0.04).

CONCLUSIONS

Stress-dose corticosteroids were only beneficial in cases of sepsis with high risk for death and even short courses may interfere with host mechanisms of bacterial clearance.

Corticosteroids in the treatment of community-acquired pneumonia in adults: a meta-analysis

Background

The benefit of corticosteroids in community-acquired pneumonia (CAP) remains controversial. We did a meta-analysis to include all the randomized controlled trials (RCTs) which used corticosteroids as adjunctive therapy, to examine the benefits and risks of corticosteroids in the treatment of CAP in adults.

Methods

Databases including Pubmed, EMBASE, the Cochrane controlled trials register, and Google Scholar were searched to find relevant trials. Randomized and quasi-randomized trials of corticosteroids treatment in adult patients with CAP were included. Effects on primary outcome (mortality) and secondary outcomes (adverse events) were accessed in this meta-analysis.

Results

Nine trials involving 1001 patients were included. Use of corticosteroids did not significantly reduce mortality (Peto odds ratio [OR] 0.62, 95% confidence interval [CI] 0.37–1.04; P = 0.07). In the subgroup analysis by the severity, a survival benefit was found among severe CAP patients (Peto OR 0.26, 95% CI 0.11–0.64; P = 0.003). In subgroup analysis by duration of corticosteroids treatment, significant reduced mortality was found among patients with prolonged corticosteroids treatment (Peto OR 0.51, 95% CI 0.26–0.97; P = 0.04; I² = 37%). Corticosteroids increased the risk of hyperglycemia (Peto OR 2.64, 95% CI 1.68–4.15; P<0.0001), but without increasing the risk of gastroduodenal bleeding (Peto OR 1.67, 95% CI 0.41–6.80; P = 0.47) and superinfection (Peto OR 1.36, 95% CI 0.65–2.84; P = 0.41).

Conclusion

Results from this meta-analysis did not suggest a benefit for corticosteroids treatment in patients with CAP. However, the use of corticosteroids was associated with improved mortality in severe CAP. In addition, prolonged corticosteroids therapy suggested a beneficial effect on mortality. These results should be confirmed by future adequately powered randomized trials.

The evolving experience with therapeutic TNF inhibition in sepsis: considering the potential influence of risk of death

INTRODUCTION

Septic shock is highly lethal and its incidence is increasing. Although TNF-α plays a key role in sepsis pathogenesis, past efforts to therapeutically inhibit it had limited success. However, there is continued interest in such therapies and there are now ongoing Phase II sepsis trials testing the effects of AZD9773, a TNF-directed polyclonal antibody fragment preparation. Experience with anti-inflammatory agents suggested that their efficacy may relate to sepsis-associated risk of death.

AREAS COVERED

An overview of the biology of TNF and experimental data implicating TNF as a key mediator in sepsis pathogenesis; a review of the earlier clinical experience with anti-TNF therapies demonstrating that when examined across 12 trials, these agents had a highly consistent overall effect which although not reaching significance, was on the side of benefit; a review of data showing that sepsis-associated risk of death may influence the efficacy of anti-inflammatory agents like anti-TNF ones and a review of the rational and clinical experience to date with AZD9773 and its precursor, CytoFab.

EXPERT OPINION

Discusses variables that may need to be accounted for to maximize the success of clinical trials in sepsis testing agents that modulate host inflammation.

The effect of heparin administration in animal models of sepsis: a prospective study in Escherichia coli-challenged mice and a systematic review and metaregression analysis of published studies

INTRODUCTION

If thrombosis contributes to sepsis, heparin titrated using activated partial thromboplastin times may be efficacious. We investigated heparin in preclinical models.

METHODS AND MAIN RESULTS

In unchallenged mice (n = 107), heparin at 100, 500, or 2500 units/kg produced activated partial thromboplastin time levels less than, within, or greater than a prespecified therapeutic range (1.5-2.5 times control), respectively. In animals (n = 142) administered intratracheal Escherichia coli challenge, compared to placebo treatment, heparin at 100, 500, or 2500 units/kg were associated with dose dependent increases in the hazard ratios of death (hazard ratio [95% confidence interval]: 1.08 [0.66, 1.76]; 1.34 [0.80, 2.24]; 3.02 [1.49, 6.10], respectively) (p = .001 for the dose effect). Compared to normal saline challenge, E. coli without heparin (i.e., with placebo) increased the activated partial thromboplastin time (p = .002) close to the therapeutic range. While heparin at 100 and 500 units/kg with E. coli further increased activated partial thromboplastin time (p < .0001 vs. placebo) within or above the therapeutic range, respectively, these did not decrease inflammatory cytokines or lung injury. In metaregression analysis of published preclinical studies, heparin improved survival with lipopolysaccharide (n = 23, p < .0001) or surgically induced infection (n = 14, p < .0001) but not monobacterial (n = 7, p = .29) challenges.

CONCLUSION

Coagulopathy with sepsis or other variables, such as type of infectious source, may influence the efficacy of heparin therapy for sepsis.

Low-dose steroids for septic shock and severe sepsis: the use of Bayesian statistics to resolve clinical trial controversies

PURPOSE

Low-dose steroids have shown contradictory results in trials and three recent meta-analyses. We aimed to assess the efficacy and safety of low-dose steroids for severe sepsis and septic shock by Bayesian methodology.

METHODS

Randomized trials from three published meta-analyses were reviewed and entered in both classic and Bayesian databases to estimate relative risk reduction (RRR) for 28-day mortality, and relative risk increase (RRI) for shock reversal and side effects.

RESULTS

In septic shock trials only (Marik meta-analysis; N = 965), the probability that low-dose steroids decrease mortality by more than 15% (i.e., RRR > 15%) was 0.41 (0.24 for RRR > 20% and 0.14 for RRR > 25%). For severe sepsis and septic shock trials combined, the results were as follows: (1) for the Annane meta-analysis (N = 1,228), the probabilities were 0.57 (RRR > 15%), 0.32 (RRR > 20%), and 0.13 (RRR > 25%); (2) for the Minneci meta-analysis (N = 1,171), the probability was 0.57 to achieve mortality RRR > 15%, 0.32 (RRR > 20%), and 0.14 (RRR > 25%). The removal of the Sprung trial from each analysis did not change the overall results. The probability of achieving shock reversal ranged from 65 to 92%. The probability of developing steroid-induced side effects was as follows: for gastrointestinal bleeding (N = 924), there was a 0.73 probability of steroids causing an RRI > 1%, 0.70 for RRI > 2%, and 0.67 for RRI > 5%; for superinfections (N = 964), probabilities were 0.81 (RRI > 1%), 0.76 (RRI > 2%), and 0.70 (RRI > 5%); and for hyperglycemia (N = 540), 0.99 (RRI > 1%), 0.97 (RRI > 2%), and 0.94 (RRI > 5%).

CONCLUSIONS

Based on clinically meaningful thresholds (RRR > 15-25%) for mortality reduction in severe sepsis or septic shock, the Bayesian approach to all three meta-analyses consistently showed that low-dose steroids were not associated with survival benefits. The probabilities of developing steroid-induced side effects (superinfections, bleeding, and hyperglycemia) were high for all analyses.

SB203580, a p38 inhibitor, improved cardiac function but worsened lung injury and survival during Escherichia coli pneumonia in mice

BACKGROUND

Supporting its therapeutic application in sepsis, p38 mitogen-activated protein kinase (MAPK) inhibition decreases cardiopulmonary injury and lethality with lipopolysaccharide challenge. However, only one preclinical study has reported the survival effects of a p38 inhibitor (SB203580, 100 mg/kg) during infection. We therefore tested SB203580 in mice (n = 763) challenged with intratracheal Escherichia coli and treated with antibiotics and fluids.

METHODS AND RESULTS

Compared with placebo, high dose SB203580 (100 mg/kg) pretreatment increased the hazards ratio of death (95% confidence interval) (3.6 [2.1, 6.1], p < 0.0001). Decreasing doses (10, 1, or 0.1 mg/kg) went from being harmful to having no significant effect (p < 0.0001 for the effect of decreasing dose). At 48 hours, but not 24 hours after E. coli, high and low dose SB203580 pretreatment decreased cardiac phosphorylated p38 MAPK levels and improved cardiac output either (p <or= 0.07). Low dose SB203580 did not alter lung neutrophils significantly but increased lung injury at 48 hours (p = 0.05). High dose decreased lung neutrophils and injury at 24 hours (p = 0.09 and 0.01, respectively) but then increased them at 48 hours (both p <or= 0.01). Lung injury was greater with high versus low dose at 48 hours (p = 0.002).

CONCLUSION

Thus, SB203580 had divergent effects on cardiac and lung function in E. coli challenged mice. Furthermore, high dose worsened survival and low dose did not improve it. Altogether, these findings suggest that clearly defining the risks and benefits of p38 MAPK inhibition is important before such treatment is applied in patients with or at risk of serious infection.

Adjunctive therapies in severe sepsis and septic shock: current place of steroids

For more than five decades, the use of corticosteroids as an adjunctive therapy to treat severe sepsis and septic shock has incited consistent debate. Negative results of the Corticosteroid Therapy of Septic Shock (CORTICUS) study evoked a revision of Surviving Sepsis Campaign guidelines suggesting a more restricted use of low-dose hydrocortisone only in patients with severe septic shock. Hemodynamic improvement by low-dose steroids was evident and independent from adrenal insufficiency, but did not improve survival. The roles of cortisol measurement and adrenal function tests for treatment decisions have been questioned. An international task force introduced the concept of critical illness-related corticosteroid insufficiency, which challenges the predominant role of adrenal dysfunction and underscores sustained inflammation due to tissue steroid resistance. Whether moderate steroid doses induce superinfections and muscle weakness is unclear. This article reviews recent publications, actual recommendations, ongoing discussions, and future perspectives.

Use of a low-dose steroid as an adjunct in the treatment, in mice, of severe sepsis caused by Burkholderia pseudomallei

Human melioidosis caused by Burkholderia pseudomallei is a severe septic disease that is associated with high mortality, even under appropriate antibiotic treatment. The therapeutic effects of low-dose hydrocortisone plus ceftazidime, and of ceftazidime alone, have recently been investigated in the treatment of acute, severe sepsis caused by B. pseudomallei, both in normal BALB/c mice and in BALB/c mice with streptozotocin-induced diabetes. The mice were infected and then treated intravenously, from day 1 or day 2 post-infection, with saline (as a control, given twice daily for 10 days), low-dose hydrocortisone (given in twice-daily doses of 5 mg/kg, for 5 days) plus ceftazidime (given in twice-daily doses of 1200 mg/kg, for 10 days), or the same doses of ceftazidime alone. Although the infected, untreated mice all died within 14 days, almost all of the treated animals were still alive at the end of the follow-up, 30 days post-infection. The addition of the steroid appeared to have no benefit, with bacterial loads and plasma concentrations of tumour necrosis factor, aspartate aminotransferase, alanine aminotransferase and creatinine decreasing similarly in all the treated groups. The infected diabetic mice given hydrocortisone-ceftazidime from day 1 (but not those given just ceftazidime from day 1) showed an increase in their blood glucose concentrations. When infected mice were treated with the low-dose steroid and lower doses of the antibiotic (in twice-daily doses of 120-600 mg/kg), the steroid not only offered no apparent benefit but seemed to reduce survival. It therefore appears that low-dose hydrocortisone, as an adjunct to antibiotic treatment, does not provide benefit in the treatment of murine melioidosis and may have negative effects on human cases of the disease who have diabetes mellitus.

Stratification is the key: inflammatory biomarkers accurately direct immunomodulatory therapy in experimental sepsis

OBJECTIVE

This study examined the effectiveness of prospective stratification to identify and target high-dose glucocorticoid therapy for subjects developing lethal sepsis.

DESIGN

Prospective, randomized, laboratory-controlled experiment.

SETTING

University research laboratory.

SUBJECTS

Adult female outbred CD-1 mice.

INTERVENTIONS

Mice (n = 88) were subjected to sepsis induced by cecal ligation and puncture (CLP). Mice were prospectively divided into two groups, predicted to die (P-DIE) or predicted to live (P-LIVE), based on plasma levels of interleukin (IL)-6 obtained 6 hours after CLP. Following stratification, dexamethasone (DEX, 2.5 mg/kg, two doses) was administered to half the animals in each group whereas the other half received saline.

MEASUREMENTS AND MAIN RESULTS

Without stratification, DEX conferred no benefit. In the P-DIE group, none of saline-treated mice lived whereas 40% of the DEX-treated mice survived. Of the nonsurvivors, 67% had death delayed by 24-48 hours compared with saline-treated mice. Twenty-four hours post-CLP, the lymphocyte count was higher in the P-DIE than in the P-LIVE mice regardless of treatment status, whereas the opposite trend was noted for neutrophils. Plasma cytokine and cytokine inhibitor levels in the saline-treated animals showed that levels in the P-DIE group were higher than those in the P-LIVE group (e.g., 60 vs. 10 ng/mL for IL-6 and 453 vs.129 ng/mL for IL-1 receptor antagonist). Interestingly, DEX therapy did not decrease 24 hours post-CLP circulating cytokines in either the P-DIE or the P-LIVE group.

CONCLUSIONS

Following CLP-induced sepsis, early and accurate survival prediction allows targeted immunosuppression that improves survival. Better survival occurred without suppression of the typical proinflammatory mediators, suggesting that the deaths were not mediated by excessive cytokine-driven inflammation. Nonspecific anti-inflammatory/immunosuppressive treatment administered to more rigorously defined cohorts may be more successful than mediator-specific drugs used indiscriminately.

The effects of steroids during sepsis depend on dose and severity of illness: an updated meta-analysis

A previous meta-analysis determined that the effects of steroids during sepsis were dose-dependent; since then, additional trials have been published. The current analysis updates our previous analysis examining the effects of steroids during sepsis. A literature search from 2004 to 2008 identified seven randomized controlled trials in adult patients; these were added to 14 previously identified trials. The effects of steroids on mortality were highly variable among the 21 trials (p <0.001, I(2) = 60%). In trials published before 1989, which involved short courses of high-dose steroids, steroids increased mortality (n = 8, I(2) = 14%, OR of death 1.39 (95% CI 1.04-1.86), p 0.03). In trials published after 1997, which involved longer courses of lower-dose steroids, steroids consistently improved shock reversal (n = 7, I(2) = 0%, OR of shock reversal 1.66 [95% CI 1.25-2.20), p <0.001), but demonstrated a more heterogeneous beneficial effect on mortality (n = 12, I(2) = 25%, OR of death 0.64 (95% CI 0.45-0.93), p 0.02). An inverse linear relationship between severity of illness and the effects of steroids on mortality was identified across all trials (p 0.03) and within the subgroup of trials published after 1997 (p 0.03); steroids were harmful in less severely ill patient populations and beneficial in more severely ill patient populations. There was no effect of response to adrenocorticotrophic hormone (ACTH) stimulation testing concerning the effects of steroids and no increase in steroid-associated adverse events. Low-dose steroids appear to improve mortality rates in patients with septic shock who are at high risk of death; however, additional trials in this subpopulation are necessary to definitively determine the role of low-dose steroids during sepsis.

CYLD is a crucial negative regulator of innate immune response in Escherichia coli pneumonia

Bacteraemic pneumonia is a common cause of sepsis in critically ill patients today and is characterized by dysregulation of inflammation. The genetic factors predisposing to bacteraemic pneumonia are not yet fully understood. Innate immunity is pivotal for host defence against invading bacteria, and nuclear factor-kappa B (NF-kappaB) is central to bacteria-induced inflammation and immune responses. The deubiquitinating enzyme CYLD has been identified as a key negative regulator for NF-kappaB. In the present study, we investigated the role of CYLD in innate immune response in Escherichia coli pneumonia. Upon E. coli inoculation, Cyld(-/-) mice were hypersusceptible to E. coli pneumonia with higher mortality. Innate immune response to E. coli was enhanced in Cyld(-/-) cells and mice. Cyld(-/-) cells exhibited enhanced NF-kappaB activation upon E. coli inoculation, and the enhanced NF-kappaB activation by E. coli was abolished by perturbing IkappaB kinase (IKK) signalling. Furthermore, IKK inhibitor rescued Cyld(-/-) mice from lethal infection during E. coli pneumonia along with reduced inflammation. Taken together, these data showed that CYLD acts as a crucial negative regulator for E. coli pneumonia by negatively regulating NF-kappaB. These findings provide novel insight into the regulation of bacteraemic pneumonia and related diseases and may help develop novel therapeutic strategies for these diseases.

Corticosteroids for community-acquired pneumonia: time to act!

The use of corticosteroids for the treatment of community-acquired pneumonia has been reported for almost 50 years. A recent systematic analysis of the relevant literature suggested that corticosteroids reduce the critical illness associated with community-acquired pneumonia. There is little doubt that a prolonged administration of a moderate dose of corticosteroids may alleviate the systemic inflammatory response and subsequent organ dysfunction in severe infection. Whether these favorable effects on morbidity may translate into better survival and quality of life needs to be addressed in additional adequately powered randomized controlled trials.