Severe sepsis: are PROWESS and PROWESS-SHOCK trials comparable? A clinical and statistical heterogeneity analysis

Recombinant Activated Protein C (rhAPC) Affects Lipopolysaccharide-Induced Mechanical Compliance Changes and Beat Frequency of mESC-Derived Cardiomyocyte Monolayers

BACKGROUND

Septic cardiomyopathy increases mortality by 70% to 90% and results in mechanical dysfunction of cells.

METHODS

Here, we created a LPS-induced in-vitro sepsis model with mouse embryonic stem cell-derived cardiomyocytes (mESC-CM) using the CellDrum technology which simultaneously measures mechanical compliance and beat frequency of mESCs. Visualization of reactive oxygen species (ROS), actin stress fibers, and mRNA quantification of endothelial protein C receptor (EPCR) and protease-activated receptor 1 (PAR1) before/after LPS incubation were used for method validation. Since activated protein C (APC) has cardioprotective effects, samples were treated with human recombinant APC (rhAPC) with/-out LPS predamage to demonstrate the application in therapeutic studies.

RESULTS

Twelve hours LPS treatment (5 μg/mL) increased ROS and decreased actin stress fiber density and significantly downregulated EPCR and PAR1 compared to control samples (0.26, 0.39-fold respectively). rhAPC application (5 μg/mL, 12 h) decreased ROS and recovered actin density, EPCR, and PAR1 levels were significantly upregulated compared to LPS predamaged samples (4.79, 3.49-fold respectively). The beat frequencies were significantly decreased after 6- (86%) and 12 h (73%) of LPS application. Mechanical compliance of monolayers significantly increased in a time-dependent manner, up to eight times upon 12-h LPS incubation compared to controls. rhAPC incubation increased the beat frequency by 127% (6h-LPS) and 123% (12h-LPS) and decreased mechanical compliance by 68% (12h-LPS) compared to LPS predamaged samples.

CONCLUSION

LPS-induced contraction dysfunction and the reversal effects of rhAPC were successfully assessed by the mechanical properties of mESC-CMs. The CellDrum technology proved a decent tool to simulate sepsis in-vitro.

The Role of Histones and Heparin in Sepsis: A Review

Septic shock with multiple organ failure is a devastating situation in clinical settings. Through the past decades, much progress has been made in the management of sepsis and its underlying pathogenesis, but a highly effective therapeutic has not been developed. Recently, macromolecules such as histones have been targeted in the treatment of sepsis. Histones primarily function as chromosomal organizers to pack DNA and regulate its transcription through epigenetic mechanisms. However, a growing body of research has shown that histone family members can also exert cellular toxicity once they relocate from the nucleus into the extracellular space. Heparin, a commonly used anti-coagulant, has been shown to possess life-saving capabilities for septic patients, but the potential interplay between heparin and extracellular histones has not been investigated. In this review, we summarize the pathogenic roles of extracellular histones and the therapeutic roles of heparin in the development and management of sepsis and septic shock.

Targeting coagulation activation in severe COVID-19 pneumonia: lessons from bacterial pneumonia and sepsis

Novel coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2), has rapidly spread throughout the world, resulting in a pandemic with high mortality. There are no effective treatments for the management of severe COVID-19 and current therapeutic trials are focused on antiviral therapy and attenuation of hyper-inflammation with anti-cytokine therapy. Severe COVID-19 pneumonia shares some pathological similarities with severe bacterial pneumonia and sepsis. In particular, it disrupts the haemostatic balance, which results in a procoagulant state locally in the lungs and systemically. This culminates in the formation of microthrombi, disseminated intravascular coagulation and multi-organ failure. The deleterious effects of exaggerated inflammatory responses and activation of coagulation have been investigated in bacterial pneumonia and sepsis and there is recognition that although these pathways are important for the host immune response to pathogens, they can lead to bystander tissue injury and are negatively associated with survival. In the past two decades, evidence from preclinical studies has led to the emergence of potential anticoagulant therapeutic strategies for the treatment of patients with pneumonia, sepsis and acute respiratory distress syndrome, and some of these anticoagulant approaches have been trialled in humans. Here, we review the evidence from preclinical studies and clinical trials of anticoagulant treatment strategies in bacterial pneumonia and sepsis, and discuss the importance of these findings in the context of COVID-19.

Murine Myocardial Transcriptome Analysis Reveals a Critical Role of COPS8 in the Gene Expression of Cullin-RING Ligase Substrate Receptors and Redox and Vesicle Trafficking Pathways

Background: The COP9 signalosome (CSN) consisting of 8 unique protein subunits (COPS1 through COPS8) serves as the cullin deneddylase, regulating the catalytic dynamics of cullin RING ligases (CRLs), the largest family of ubiquitin ligases Background: The COP9 signalosome (CSN) consisting of 8 unique protein subunits (COPS1 through COPS8) serves as the cullin deneddylase, regulating the catalytic dynamics of cullin RING ligases (CRLs), the largest family of ubiquitin ligases. Supported primarily by the decrease of substrate receptor (SR) proteins of CRLs in cells deficient of a CSN subunit, CSN-mediated cullin deneddylation is believed to prevent autoubiquitination and self-destruction of the SR in active CRLs. However, it is unclear whether the decrease in SRs is solely due to protein destabilization. Moreover, our prior studies have demonstrated that cardiac specific knockout of Cops8 (Cops8-CKO) impairs autophagosome maturation and causes massive necrosis in cardiomyocytes but the underlying mechanism remains poorly understood. Given that Cops8 is nucleus-enriched and a prior report showed its binding to the promoter of several genes and association of its ablation with decreased mRNA levels of these genes, we sought to determine the dynamic changes of myocardial transcriptome in mice with perinatal Cops8-CKO and to explore their functional implications. Methods and Results: Myocardial transcriptomes of Cops8^flox/flox , Cops8^flox/+::Myh6-Cre, and Cops8^flox/flox::Myh6-Cre littermate mice at postnatal 2 and 3 weeks were analyzed. The data were imported into an in-house analysis pipeline using Bioconductor for quantile normalization and statistical analysis. Differentially expressed genes (DEGs) between groups at each time point or between time points within the group were revealed by t-test. Genes with p < 0.05 after Benjamini and Hochberg false discovery rate correction for multiple hypothesis testing were considered as significant DEGs. We found that (1) the Ingenuity Pathway Analysis (IPA) revealed significant enrichment of DEGs in multiple pathways, especially those responding to oxidative stress, in homozygous Cops8-CKO hearts at both 2 and 3 weeks, corroborating the occurrence of massive cardiomyocyte necrosis at 3 weeks; (2) the decreases in multiple CRL SR proteins were associated with decreased transcript levels; and (3) enrichment of DEGs in the chromatin remodeling pathway and the microtubule motility and vesicle trafficking pathways. Conclusions: Our data are consistent with the notion that Cops8/CSN plays a role in the transcriptional regulation of CRL SRs and in the redox and vesicle trafficking pathways.

Hierarchical cluster analysis in clinical research with heterogeneous study population: highlighting its visualization with R

Big data clinical research typically involves thousands of patients and there are numerous variables available. Conventionally, these variables can be handled by multivariable regression modeling. In this article, the hierarchical cluster analysis (HCA) is introduced. This method is used to explore similarity between observations and/or clusters. The result can be visualized using heat maps and dendrograms. Sometimes, it would be interesting to add scatter plot and smooth lines into the panels of the heat map. The inherent R heatmap package does not provide this function. A series of scatter plots can be created using lattice package, and then background color of each panel is mapped to the regression coefficient by using custom-made panel functions. This is the unique feature of the lattice package. Dendrograms and color keys can be added as the legend elements of the lattice system. The latticeExtra package provides some useful functions for the work.

Refractory septic shock in children: a European Society of Paediatric and Neonatal Intensive Care definition

Purpose

Although overall paediatric septic shock mortality is decreasing, refractory septic shock (RSS) is still associated with high mortality. A definition for RSS is urgently needed to facilitate earlier identification and treatment. We aim to establish a European society of paediatric and neonatal intensive care (ESPNIC) experts’ definition of paediatric RSS.

Methods

We conducted a two-round Delphi study followed by an observational multicentre retrospective study. One hundred and fourteen paediatric intensivists answered a clinical case-based, two-round Delphi survey, identifying clinical items consistent with RSS. Multivariate analysis of these items in a development single-centre cohort (70 patients, 30 % mortality) facilitated development of RSS definitions based on either a bedside or computed severity score. Both scores were subsequently tested in a validation cohort (six centres, 424 patients, 11.6 % mortality).

Results

From the Delphi process, the draft definition included evidence of myocardial dysfunction and high blood lactate levels despite high vasopressor treatment. When assessed in the development population, each item was independently associated with the need for extracorporeal life support (ECLS) or death. Resultant bedside and computed septic shock scores had high discriminative power against the need for ECLS or death, with areas under the receiver operating characteristics curve of 0.920 (95 % CI 0.89–0.94), and 0.956 (95 % CI 0.93–0.97), respectively. RSS defined by a bedside score equal to or higher than 2 and a computed score equal to or higher than 3.5 was associated with a significant increase in mortality.

Conclusions

This ESPNIC definition of RSS accurately identifies children with the most severe form of septic shock.

Electronic supplementary material

The online version of this article (doi:10.1007/s00134-016-4574-2) contains supplementary material, which is available to authorized users.

The efficacy of activated protein C for the treatment of sepsis: incorporating observational evidence with a Bayesian approach

OBJECTIVE

The present study aimed to combine observational evidence with randomised controlled trials (RCTs) by using the Bayesian approach.

DATA SOURCES

Electronic databases, including PubMed, Cochrane Central Register of Controlled Trials (CENTRAL), ISI Web of Science, EMBASE and EBSCO were searched from inception to January 2014.

STUDY ELIGIBILITY

RCTs and observational studies (OS) investigating the effectiveness of activated protein C (aPC) on mortality reduction were included for analysis.

PARTICIPANTS

Patients with sepsis.

INTERVENTION

aPC.

SYNTHESIS METHODS

Observational evidence was incorporated into the analysis by using power transformed priors in a Bayesian. Trial sequential analysis was performed to examine changes over time and whether further studies need to be conducted.

MAIN RESULTS

a total of 7 RCTs and 12 OS were included for the analysis. There was moderate heterogeneity among included RCTs (I(2)=48.6%, p=0.07). The pooled OR for mortality from RCTs was 1.00 (95% CI 0.84 to 1.19). In OS, there was potential publication bias as indicated by the funnel plot and the pooled OR for mortality with the use of aPC was 0.67 (95% CI 0.62 to 0.72). The pooled effect sizes of RCTs were changed by using different power transform priors derived from observational evidence. When observational evidence was used at its 'face value', the treatment effect of aPC was statistically significant in reducing mortality.

CONCLUSIONS

while RCT evidence showed no beneficial effect of aPC on sepsis, observational evidence showed a significant treatment effect of aPC. By using power transform priors in Bayesian model, we explicitly demonstrated how RCT evidence could be changed by observational evidence.

TRIAL REGISTRATION NUMBER

The protocol for the current study was registered in PROSPERO (registration number: CRD42014009562).

Overexpression of activated protein C hampers bacterial dissemination during pneumococcal pneumonia

Background

During pneumonia, inflammation and coagulation are activated as part of anti-bacterial host defense. Activated protein C (APC) has anticoagulant and anti-inflammatory properties and until recently was a registered drug for the treatment of severe sepsis. Streptococcus (S.) pneumoniae is the most common causative pathogen in community-acquired pneumonia.

Methods

We aimed to investigate the effect of high APC levels during experimental pneumococcal pneumonia. Wild type (WT) and APC overexpressing (APC^high)-mice were intranasally infected with S. pneumoniae and sacrificed after 6, 24 or 48 hours, or followed in a survival study.

Results

In comparison to WT mice, APC^high-mice showed decreased bacterial dissemination to liver and spleen, while no differences in bacterial loads were detected at the primary site of infection. Although no differences in the extent of lung histopathology were seen, APC^high-mice showed a significantly decreased recruitment of neutrophils into lung tissue and bronchoalveolar lavage fluid. Activation of coagulation was not altered in APC^high-mice. No differences in survival were observed between WT and APC^high-mice (P =0.06).

Conclusion

APC overexpression improves host defense during experimental pneumococcal pneumonia. This knowledge may add to a better understanding of the regulation of the inflammatory and procoagulant responses during severe Gram-positive pneumonia.

Electronic supplementary material

The online version of this article (doi:10.1186/s12879-014-0559-3) contains supplementary material, which is available to authorized users.

The next generation of sepsis clinical trial designs: what is next after the demise of recombinant human activated protein C?*

OBJECTIVE

The developmental pipeline for novel therapeutics to treat sepsis has diminished to a trickle compared to previous years of sepsis research. While enormous strides have been made in understanding the basic molecular mechanisms that underlie the pathophysiology of sepsis, a long list of novel agents have now been tested in clinical trials without a single immunomodulating therapy showing consistent benefit. The only antisepsis agent to successfully complete a phase III clinical trial was human recumbent activated protein C. This drug was taken off the market after a follow-up placebo-controlled trial (human recombinant activated Protein C Worldwide Evaluation of Severe Sepsis and septic Shock [PROWESS SHOCK]) failed to replicate the favorable results of the initial registration trial performed ten years earlier. We must critically reevaluate our basic approach to the preclinical and clinical evaluation of new sepsis therapies.

DATA SOURCES

We selected the major clinical studies that investigated interventional trials with novel therapies to treat sepsis over the last 30 years.

STUDY SELECTION

Phase II and phase III trials investigating new treatments for sepsis and editorials and critiques of these studies.

DATA EXTRACTION

Selected manuscripts and clinical study reports were analyzed from sepsis trials. Specific shortcomings and potential pit falls in preclinical evaluation and clinical study design and analysis were reviewed and synthesized.

DATA SYNTHESIS

After review and discussion, a series of 12 recommendations were generated with suggestions to guide future studies with new treatments for sepsis.

CONCLUSIONS

We need to improve our ability to define appropriate molecular targets for preclinical development and develop better methods to determine the clinical value of novel sepsis agents. Clinical trials must have realistic sample sizes and meaningful endpoints. Biomarker-driven studies should be considered to categorize specific "at risk" populations most likely to benefit from a new treatment. Innovations in clinical trial design such as parallel crossover design, alternative endpoints, or adaptive trials should be pursued to improve the outlook for future interventional trials in sepsis.

The aPC treatment improves microcirculation in severe sepsis/septic shock syndrome

Background

The role of recombinant activated protein C (aPC) during sepsis is still controversial. It showed anti-inflammatory effect and improved the microvascular perfusion in experimental models of septic shock. The present study was aimed at testing the hypothesis that recombinant aPC therapy improves the microcirculation during severe sepsis.

Methods

Prospective observational study on patients admitted in a 12-beds intensive care unit of a university hospital from July 2010 to December 2011, with severe sepsis and at least two sepsis-induced organ failures occurring within 48 hours from the onset of sepsis, who received an infusion of aPC (24 mcg/kg/h for 96 hours) (aPC group). Patients with contraindications to aPC administration were also monitored (no-aPC group).

At baseline (before starting aPC infusion, T0), after 24 hours (T1a), 48 hours (T1b), 72 hours (T1c) and 6 hours after the end of aPC infusion (T2), general clinical and hemodynamic parameters were collected and the sublingual microcirculation was evaluated with sidestream dark-field imaging. Total vessel density (TVD), perfused vessel density (PVD), De Backer score, microvascular flow index (MFIs), the proportion of perfused vessels (PPV) and the flow heterogeneity index (HI) were calculated for small vessels. The perfused boundary region (PBR) was measured as an index of glycocalyx damage. Variables were compared between time points and groups using non parametric or parametric statistical tests, as appropriate.

Results

In the 13 aPC patients mean arterial pressure (MAP), base excess, lactate, PaO2/FiO2 and the Sequential Organ Failure Assessment (SOFA) score significantly improved over time, while CI and ITBVI did not change. MFIs, TVD, PVD, PPV significantly increased over time and the HI decreased (p < 0.05 in all cases), while the PBR did not change. No-aPC patients (n = 9) did not show any change in the microcirculation over time. A positive correlation was found between MFIs and MAP. TVD, PVD and De Backer score negatively correlated with norepinephrine dose, and the SOFA score negatively correlated with MFIs, TVD and PVD.

Conclusions

aPC significantly improves the microcirculation in patients with severe sepsis/septic shock.

Trial registration

NCT01806428