Granulocyte colony-stimulating factor and modulation of inflammatory cells in sepsis

New frontiers in precision medicine for sepsis-induced immunoparalysis

INTRODUCTION

In the last decade, the sepsis research field has shifted focus from targeting hyperinflammation to reversing sepsis-induced immunoparalysis. Sepsis-induced immunoparalysis is very heterogeneous: the magnitude and the nature of the underlying immune defects differ considerably between patients, but also within individuals over time. Therefore, a 'one-treatment-fits-all' strategy for sepsis-induced immunoparalysis is bound to fail, and an individualized 'precision medicine' approach is required. Such a strategy is nevertheless hampered by the unsuitability of the currently available markers to identify the many immune defects that can manifest in individual patients. Areas covered: We describe the currently available markers for sepsis-induced immunoparalysis and limitations pertaining to their use. Furthermore, future prospects and caveats are discussed, focusing on 'omics' approaches: genomics, transcriptomics, epigenomics, and metabolomics. Finally, we present a contemporary overview of adjuvant immunostimulatory therapies. Expert opinion: The integration of multiple omics techniques offers a systems biology approach which can yield biomarker profiles that accurately and comprehensively gauge the extent and nature of sepsis-induced immunoparalysis. We expect this development to be instrumental in facilitating precision medicine for sepsis-induced immunoparalysis, consisting of the application of targeted immunostimulatory therapies and follow-up measurements to monitor the response to treatment and to titrate or adjust medication.

Randomized, double-blind, placebo-controlled trial of granulocyte colony-stimulating factor in patients with septic shock

OBJECTIVE

To investigate the effect of early administration of granulocyte colony-stimulating factor (G-CSF) on hospital mortality in nonneutropenic patients with septic shock, excluding patients with melioidosis.

DESIGN

A randomized, placebo-controlled, double-blinded clinical trial.

SETTING AND PATIENTS

Adult patients with septic shock admitted to the Royal Darwin Hospital Intensive Care Unit.

INTERVENTIONS

Patients were randomized to receive G-CSF or placebo intravenously daily for 10 days, in addition to routine management of septic shock.

MEASUREMENTS

Primary outcome was hospital mortality. Secondary outcomes included intensive care unit mortality, intensive care unit and hospital length of stay, ventilator hours, and time to resolution of shock. Patient comorbidities, baseline and daily physiology, and organ function were collected.

RESULTS

Of 166 patients enrolled, 83 were allocated to receive G-CSF (81 included in analysis) and 83 were allocated to receive placebo. At baseline, 30% of patients had diabetes, 18% were known to have renal impairment or failure, and 38% had a history of hazardous alcohol use. The two groups had similar comorbidities at baseline and a similar severity of illness. The in-hospital mortality was 27% in the G-CSF group and 25% in the placebo group. Secondary end points were not different between groups. There was a higher rate of new organ failure in G-CSF-treated patients than placebo-treated patients (50% vs. 33%, p = .03), most of which was accounted for by new liver dysfunction (11% vs. 1%, p = .007). There was no significant difference in the proportion of patients with troponin I of >0.08 mg/L (78% vs. 66%, p = .09), and the prevalence of acute myocardial infarction (6% vs. 4%, p = .55) was not different during the study. The median peak troponin I level was higher in the G-CSF group (0.5 vs. 0.14 mg/L, p = .007), but baseline levels were not available.

CONCLUSION

G-CSF does not improve outcomes in patients with septic shock, excluding melioidosis. Increased hepatic dysfunction and higher peak troponin levels in patients receiving G-CSF have not been reported in previous clinical trials and warrant further investigation.

THE EFFECTS OF GRANULOCYTE COLONY-STIMULATING FACTOR IN PRECLINICAL MODELS OF INFECTION AND ACUTE INFLAMMATION

The cytokine granulocyte colony-stimulating factor (G-CSF) is a potent endogenous trigger for the release of neutrophils from bone marrow stores and for their activation for enhanced antimicrobial activity. G-CSF has been widely evaluated in preclinical models of acute illness, with generally promising though divergent results. A recombinant G-CSF molecule has recently undergone clinical trials to assess its efficacy as an adjuvant therapy in community-acquired and nosocomial pneumonia, however, these studies failed to provide convincing evidence of benefit. We undertook a systematic review of the published literature reporting the effects of modulation of G-CSF in preclinical in vivo models to determine whether evidence of differential efficacy might explain the disappointing results of human studies and point to disease states that might be more likely to benefit from G-CSF therapy. G-CSF has been evaluated in 86 such studies involving a variety of different models. The strongest evidence of benefit was seen in studies involving intraperitoneal challenge with live organisms; benefit was evident whether the agent was given before or after challenge. G-CSF demonstrates anti-inflammatory activity in models of systemic challenge with viable organisms or endotoxin, but only when the agent is given before challenge; evidence of benefit after challenge was minimal. Preclinical models of intrapulmonary challenge only show efficacy when the cytokine is administered before the infectious challenge, and suggested harm in gram-negative pneumonia resulting from challenge with Escherichia coli or Klebsiella. There is little evidence for therapeutic efficacy in noninfectious models of acute illness. We conclude that the most promising populations for evaluation of G-CSF are neutropenic patients with invasive infection and patients with intra-abdominal infection, particularly those with the syndrome of tertiary, or recurrent, peritonitis. Significant variability in the design and reporting of studies of preclinical models of acute illness precludes more sophisticated data synthesis.

Such stuff as dreams are made on: mediator-directed therapy in sepsis

Sepsis, a life-threatening disorder that arises through the body's response to infection, is the leading cause of death and disability for patients in an intensive care unit. Advances in the understanding of the complex biological processes responsible for the clinical syndrome have led to the identification of many promising new therapeutic targets, including bacterial toxins, host-derived mediators, and downstream processes such as coagulation and the endocrine response. Diverse therapies directed against these targets have shown dramatic effects in animal models; however, in humans, their impact has been frustratingly modest, and only one agent--recombinant activated protein C--has achieved regulatory approval. This review summarizes the approaches that have been evaluated in clinical trials, explores the reasons for the discordance between biological promise and clinical reality, and points to approaches that may lead to greater success in the future.

An audit of the use of granulocyte colony-stimulating factor in septic shock

BACKGROUND

Granulocyte colony-stimulating factor (G-CSF) stimulates the production of neutrophils and modulates the function and activity of developing and mature neutrophils. In septic shock, the immune system can be considered one of the failing organ systems. G-CSF improves immune function and may be a useful adjunctive therapy in patients with septic shock.

AIM

To evaluate the introduction of G-CSF as an adjunct to our standard treatment for community-acquired septic shock.

METHODS

We performed a prospective data collection and analysis to determine whether the addition of G-CSF to our standard treatment for community-acquired septic shock was associated with improved hospital outcome, compared with an historical cohort of similar patients. We included all patients admitted to the Intensive Care Unit (ICU) with community-acquired septic shock between December 1998 and March 2000. Patients received 300 microg G-CSF intravenously daily for 10 days in addition to our standard treatment for community-acquired septic shock. G-CSF was discontinued early if the patient was discharged from ICU before 10 days or if the absolute neutrophil count exceeded 75 x 10(6)/mL.

RESULTS

A total of 36 patients with community-acquired septic shock, an average Apache 2 score of 26.7, and a predicted mortality of 0.79, were treated with G-CSF from December 1998 to March 2000. Hospital mortality was 31% compared with an historical cohort of 11 similar patients with a hospital mortality of 73% (P = 0.018). In the subgroup of patients with melioidosis septic shock, the hospital survival improved from 5% to 100% (P < 0.0001). No significant adverse events occurred as a result of the administration of G-CSF.

CONCLUSION

G-CSF is a safe adjunctive therapy in community-acquired septic shock and may be associated with improved outcome. The use of G-CSF in septic shock should undergo further investigation to define subgroups of patients who may benefit from G-CSF. The use of G-CSF in patients with septic shock due to Burkholderia pseudomallei is recommended.

Granulocyte colony-stimulating factor improves deficient in vitro neutrophil transendothelial migration in patients with advanced liver disease

Bacterial infections are frequent complications in patients with liver cirrhosis. Cirrhotic patients present abnormalities in both innate and adaptive immune responses, including a deficient neutrophil recruitment to infected sites. The purpose of this study was to assess neutrophil-endothelium interactions in cirrhotic patients and evaluate the effects of G-CSF on this process. We studied neutrophil adhesion and transendothelial migration in 14 cirrhotic patients and 14 healthy controls. We also analyzed neutrophil expression of the adhesion molecules CD62L and CD11b in whole blood by flow cytometry. Cirrhotic patients expressed higher levels of CD11b than healthy controls, whereas CD62L expression was significantly lower, suggesting exposure of neutrophils to activating agents within the bloodstream. Neutrophils from cirrhotic patients showed increased adhesion to both resting and tumor necrosis factor alpha-stimulated microvascular endothelial cells and decreased transendothelial migration. Granulocyte colony-stimulating factor (G-CSF) (100 ng/ml) significantly enhanced neutrophil adhesion to microvascular endothelial cells in healthy controls but not in cirrhotic patients. G-CSF also significantly improved neutrophil transmigration in cirrhotic patients and healthy controls. In conclusion, cirrhotic patients exhibit increased neutrophil adhesion to microvascular endothelium and deficient transendothelial migration. G-CSF enhances neutrophil transendothelial migration in cirrhotic patients despite having no effect on neutrophil adhesion. Therefore, G-CSF may be able to increase neutrophil recruitment into infected sites in these patients.

Effect of in vivo infusion of granulocyte colony-stimulating factor on immune function

As the applications of hematopoietic growth factors increase, their complex impact on host defense and immune responses continues to unfold. The effect of the administration of granulocyte colony-stimulating factor (G-CSF) on bacterial defense, proliferation of lymphocytes, and cytokine production by lymphocytes and peripheral blood mononuclear cells (PBMC) was studied. The effect of G-CSF administration on the phenotype of the cells in the major hematopoietic organs was studied as well. ACI rats were given 10 mg/kg/day G-CSF or vehicle daily for 4 days. Isolated bone marrow neutrophils and enterocytes from treated animals showed a greater bactericidal activity than controls. Proliferation of mitogen-stimulated lymphocytes and PBMC was reduced in G-CSF-treated animals. The production of proinflammatory cytokines, tumor necrosis factor (TNF), and interleukin 6 (IL-6) by lymphocytes and PBMC was reduced by G-CSF pretreatment. G-CSF administration caused an increase in IL-4 (Th2 cytokine) release and a decrease in interferon-gamma (IFNgamma, Th1 cytokine) release by mitogen-stimulated lymphocytes. Cytometric analysis of cells in the progenitor cell region indicated a large increase in immature cells in the bone marrow of G-CSF-treated animals compared with sham along with an increase in B cells and a decrease in polymorphonuclear leukocytes (PMNs). In addition, cytometric analysis showed a large increase in PMNs in blood and splenocytes of the treated animals compared with sham. This study confirms and extends previous observations that G-CSF administration has a number of effects that might simultaneously enhance host defense while reducing the risk of developing uncontrolled systemic inflammation. This may also be efficacious in prolonging graft survival and reducing graft vs. host disease.

Acute G-CSF therapy is not protective during lethal E. coli sepsis

We investigated whether decreases in circulating polymorphonuclear neutrophils (PMN) during lethal Escherichia coli (E. coli) sepsis in canines are related to insufficient host granulocyte colony-stimulating factor (G-CSF). Two-year-old purpose-bred beagles had intraperitoneal E. coli-infected or -noninfected fibrin clots surgically placed. By 10 to 12 h following clot, both infected survivors and nonsurvivors had marked increases (P = 0.001) in serum G-CSF levels (mean peak G-CSF ng/ml +/- SE, 1,931 +/- 364 and 2,779 +/- 681, respectively) compared with noninfected controls (134 +/- 79), which decreased at 24 to 48 h. Despite increases in G-CSF, infected clot placement caused delayed (P = 0.06) increases in PMN (mean +/- SE change from baseline in cells x 10(3)/mm(3) at 24 and 48 h) in survivors (+3.9 +/- 3.9 and +13.8 +/- 3.6) compared with noninfected controls (+13.1 +/- 2.8 and +9.1 +/- 2.5). Furthermore, infected nonsurvivors had decreases in PMN (-1.4 +/- 1.0 and -1.1 +/- 2.3, P = 0.006 compared with the other groups). We next investigated whether administration of G-CSF immediately after clot placement and continued for 96 h to produce more rapid and prolonged high levels of G-CSF after infection would alter PMN levels. Although G-CSF caused large increases in PMN compared with control protein from 2 to 48 h following clot in noninfected controls, it caused much smaller increases in infected survivors and decreases in infected nonsurvivors (P = 0.03 for the ordered effect of G-CSF comparing the three groups). Thus insufficient host G-CSF is unlikely the cause of decreased circulating PMN in this canine model of sepsis. Other factors associated with sepsis either alone or in combination with G-CSF itself may reduce increases or cause decreases in circulating PMN.

Novel nonantibiotic therapies for pneumonia: cytokines and host defense

Effective host defense against bacterial infection is dependent on the activation and recruitment of phagocytic cells. The initiation, maintenance, and resolution of this inflammatory response in the setting of bacterial pneumonia is dependent on the expression of cytokines. As the complexities of the host-pathogen interaction are further dissected and unraveled, immunologic manipulation of cytokine expression will likely become an important adjuvant therapy in the treatment of serious lung infections.

The effects of granulocyte colony-stimulating factor and neutrophil recruitment on the pulmonary chemokine response to intratracheal endotoxin

Although G-CSF has been shown to increase neutrophil (polymorphonuclear leukocyte, PMN) recruitment into the lung during pulmonary infection, relatively little is known about the local chemokine profiles associated with this enhanced PMN delivery. We investigated the effects of G-CSF and PMN recruitment on the pulmonary chemokine response to intratracheal LPS. Rats pretreated twice daily for 2 days with an s.c. injection of G-CSF (50 microg/kg) were sacrificed at either 90 min or 4 h after intratracheal LPS (100 microg) challenge. Pulmonary recruitment of PMNs was not observed at 90 min post LPS challenge. Macrophage inflammatory protein-2 (MIP-2) and cytokine-induced neutrophil chemoattractant (CINC) concentrations in bronchoalveolar lavage (BAL) fluid were similar in animals pretreated with or without G-CSF at this time. G-CSF pretreatment enhanced pulmonary recruitment of PMNs (5-fold) and greatly reduced MIP-2 and CINC levels in BAL fluid at 4 h after LPS challenge. In vitro, the presence of MIP-2 and CINC after LPS stimulation of alveolar macrophages was decreased by coculturing with circulating PMNs but not G-CSF. G-CSF had no direct effect on LPS-induced MIP-2 and CINC mRNA expression by alveolar macrophages. Pulmonary recruited PMNs showed a significant increase in cell-associated MIP-2 and CINC. Cell-associated MIP-2 and CINC of circulating PMNs were markedly increased after exposure of these cells to the BAL fluid of LPS-challenged lungs. These data suggest that recruited PMNs are important cells in modulating the local chemokine response. G-CSF augments PMN recruitment and, thereby, lowers local chemokine levels, which may be one mechanism resulting in the subsidence of the host proinflammatory response.

Colony-Stimulating Factors in the Therapeutic Approach to Sepsis

Sepsis and its complications continue to be a leading cause of death in the United States despite availability of potent broad-spectrum antimicrobial agents. Current in vitro, ex vivo, animal, and human data are reviewed. Present data shows that colony-stimulating factors (CSFs), granulocyte CSFs, and granulocyte-macrophage CSFs are very effective in raising the leukocyte count and shortening the number of neutropenic days. CSFs in some studies improved outcome of neutropenic septic patients especially when given very early. However, there are studies that do not show any benefit. CSFs appear to be safe and should be limited to septic, neutropenic patients whose duration of neutropenia is anticipated to be prolonged, or to patients who are seriously ill.

Acute lung injury, acute respiratory distress syndrome and inhalation injury: an overview

Acute Lung Injury (ALI) and the Acute Respiratory Distress Syndrome (ARDS) are severe respiratory diseases that have a very poor prognosis and have numerous causes. Despite a great deal of research and investigation since the initial description of ARDS 30 years ago many questions about the pathogenesis, treatment and outcome of the disease remain unanswered. Although there is evidence to suggest that outcome of ALI and ARDS is improving, the reasons why are unknown and there is not yet a well developed treatment for these diseases. Inhalation injury resulting from exposure to pyrolysis and combustion atmospheres is among the causes of ALI/ARDS. Little is known of the mechanisms of fire related inhalation injury that results in the development of ALI/ARDS. There is a paucity of information about fire atmosphere exposure response relationships for smoke-induced inhalation injury. Although there is considerable information about the pulmonary toxicity of many of the more common constituents of fire atmospheres, little is known about the pulmonary toxicity of mixtures of these constituents. Fire related pulmonary health risks are of particular concern to the Navy due to the limited opportunity to escape the inhalation hazards posed by shipboard fires. Consequently the Naval Medical Research Institute Detachment (Toxicology) has undertaken a research program to develop research models of combustion atmosphere induced ALI/ARDS which can be exploited to systematically address some of the questions surrounding fire related ALI/ARDS. ALI/ARDS has been the topic of a vast amount of research, numerous symposia, working groups and their published proceedings, book chapters, and books. Less information is available regarding experimental models of smoke induced lung damage, however the literature on the subject is extensive. Consequently this article is intended to provide the reader with a primer or cursory "overview" of ALI and ARDS from a toxicological perspective and should not be considered comprehensive.

Innate immunity, cytokines, and pulmonary host defense

Effective host defense against bacterial infection is dependent on the activation and recruitment of phagocytic cells. The initiation, maintenance, and resolution of this inflammatory response in the setting of bacterial pneumonia is dependent on the expression of cytokines. As the complexities of the host-pathogen interaction are further dissected and unraveled, immunologic manipulation of cytokine expression will likely become an important adjuvant therapy in the treatment of serious lung infections.

The American-European Consensus Conference on ARDS, part 2: Ventilatory, pharmacologic, supportive therapy, study design strategies, and issues related to recovery and remodeling. Acute respiratory distress syndrome

The acute respiratory distress syndrome (ARDS) continues as a contributor to the morbidity and mortality of patients in intensive care units throughout the world, imparting tremendous human and financial costs. During the last 10 years there has been a decline in ARDS mortality without a clear explanation. The American-European Consensus Committee on ARDS was formed to re-evaluate the standards for the ICU care of patients with acute lung injury (ALI), with regard to ventilatory strategies, the more promising pharmacologic agents, and the definition and quantification of pathologic features of ALI that require resolution. It was felt that the definition of strategies for the clinical design and coordination of studies between centers and continents was becoming increasingly important to facilitate the study of various new therapies for ARDS.

The American-European Consensus Conference on ARDS, part 2. Ventilatory, pharmacologic, supportive therapy, study design strategies and issues related to recovery and remodeling

The acute respiratory distress syndrome (ARDS) continues as a contributor to the morbidity and mortality of patients in intensive care units throughout the world, imparting tremendous human and financial costs. During the last ten years there has been a decline in ARDS mortality without a clear explanation. The American-European Consensus Committee on ARDS was formed to re-evaluate the standards for the ICU care of patients with acute lung injury (ALI), with regard to ventilatory strategies, the more promising pharmacologic agents, and the definition and quantification of pathological features of ALI that require resolution. It was felt that the definition of strategies for the clinical design and coordination of studies between centers and continents was becoming increasingly important to facilitate the study of various new therapies for ARDS.

Anti-inflammatory cytokine profile and mortality in febrile patients

BACKGROUND

An anti-inflammatory cytokine profile on whole-blood stimulation in vitro is associated with fatal outcome of meningococcal disease. We investigated whether an anti-inflammatory cytokine profile in the circulation is associated with adverse outcome in other infectious diseases.

METHODS

We enrolled 464 consecutive patients (272 men, 192 women) who presented to hospital with fever (> or = 38.2 degrees C). On admission we measured plasma interleukin 10 (IL-10) and tumour necrosis factor alpha (TNF alpha), and collected clinical and microbiological data on the febrile illness, then followed up all patients for clinical outcome.

FINDINGS

In at least 399 of the 464 patients fever was caused by infection. 33 patients died after a median hospital stay of 11 days (interquartile range 3-20). Concentrations of IL-10 were significantly higher in non-survivors (median 169 pg/mL [IQR 83-530]) than in survivors (median 88 pg/mL [42-235], p=0.042). When dichotomised around the median, the mortality risk was two times higher in patients who had high concentrations of IL-10 than in those with low concentrations (relative risk 2.39 [95% CI 1.07-5.33]), in patients with low and high concentrations of TNF alpha. In the 406 patients without haemodynamic deterioration in the first 24 h, IL-10 was higher and TNF alpha lower in patients who died than in those who survived. The ratio of IL-10 to TNF alpha was higher in non-survivors (median 6.9 [3.0-21.0]) than in survivors (median 3.9 [2.0-7.0], p=0.040). This ratio was highest in patients who died without underlying disease (median 21.5 [5.0-25.0]). Age, sex, and duration of fever before admission did not explain the differences in IL-10 and TNF alpha.

INTERPRETATION

An anti-inflammatory cytokine profile of a high ratio of IL-10 to TNF alpha is associated with fatal outcome in febrile patients with community-acquired infection. Our findings caution against a widespread use of proinflammatory cytokine inhibition in patients with sepsis.