Effects of exogenous recombinant human granulocyte colony-stimulating factor (filgrastim, rhG-CSF) on neutrophils of critically ill patients with systemic inflammatory response syndrome depend on endogenous G-CSF plasma concentrations on admission

Investigation of the pH-dependent aggregation mechanisms of GCSF using low resolution protein characterization techniques and advanced molecular dynamics simulations

Granulocyte-colony stimulating factor (GCSF) is a widely used therapeutic protein to treat neutropenia. GCSF has an increased propensity to aggregate if the pH is increased above 5.0. Although GCSF is very well experimentally characterized, the exact pH-dependent aggregation mechanism of GCSF is still under debate. This study aimed to model the complex pH-dependent aggregation behavior of GCSF using state-of-the-art simulation techniques. The conformational stability of GCSF was investigated by performing metadynamics simulations, while the protein-protein interactions were investigated using coarse-grained (CG) simulations of multiple GCSF monomers. The CG simulations were directly compared with small-angle X-ray (SAXS) data. The metadynamics simulations demonstrated that the orientations of Trp residues in GCSF are dependent on pH. The conformational change of Trp residues is due to the loss of Trp-His interactions at the physiological pH, which in turn may increase protein flexibility. The helical structure of GCSF was not affected by the pH conditions of the simulations. Our CG simulations indicate that at pH 4.0, the colloidal stability may be more important than the conformational stability of GCSF. The electrostatic potential surface and CG simulations suggested that the basic residues are mainly responsible for colloidal stability as deprotonation of these residues causes a reduction of the highly positively charged electrostatic barrier close to the aggregation-prone long loop regions.

A randomized case-controlled study of recombinant human granulocyte colony stimulating factor for the treatment of sepsis in preterm neutropenic infants

BACKGROUND

To investigate the efficacy and safety of recombinant human granulocyte colony-stimulating factor, recombinant human granulocyte-macrophage colony-stimulating factor (rhG-CSF) to treat sepsis in neutropenic preterm infants.

METHODS

Fifty-six neutropenic preterm infants with suspected or culture-proven sepsis hospitalized in Zeynep Kamil Maternity and Children's Educational and Training Hospital, Kozyatağı/Istanbul, Turkey between January 2008 and January 2010 were enrolled. Patients were randomized either to receive rhG-CSF plus empirical antibiotics (Group I) or empirical antibiotics alone (Group II). Clinical features were recorded. Daily complete blood count was performed until neutropenia subsided. Data were analyzed using SPSS version 11.5.

RESULTS

Thirty-three infants received rhG-CSF plus antibiotic treatment and 23 infants received antibiotic treatment. No drug-related adverse event was recorded. Absolute neutrophil count values were significantly higher on the 2(nd) study day and 3(rd) study day in Group I. Short-term mortality did not differ between the groups.

CONCLUSION

Treatment with rhG-CSF resulted in a more rapid recovery of ANC in neutropenic preterm infants. However, no reduction in short-term mortality was documented.

Colony-stimulating factors in the prevention and management of infectious diseases

Colony-stimulating factors (CSFs) are attractive adjunctive anti-infective therapies. Used to enhance innate host defenses against microbial pathogens, the myeloid CSFs increase absolute numbers of circulating innate immune effector cells by accelerating bone marrow production and maturation, or augment the function of those cells through diverse effects on chemotaxis, phagocytosis, and microbicidal functions. This article summarizes the evidence supporting the accepted clinical uses of the myeloid CSFs in patients with congenital or chemotherapy-induced neutropenia, and presents an overview of proposed and emerging uses of the CSFs for the prevention and treatment of infectious diseases in other immunosuppressed and immunocompetent patient populations.

Use of granulocyte colony-stimulating factor in patients with severe sepsis or septic shock

PURPOSE

The efficacy and safety of granulocyte colony-stimulating factor (G-CSF) in critically ill patients with severe sepsis or septic shock were evaluated.

SUMMARY

The medical literature was reviewed to identify published trials, case reports, and case series on the use of G-CSF in critically ill patients for treatment of severe sepsis or septic shock. G-CSF has been evaluated as an adjunct to standard care for critically ill patients. Initial studies involving critically ill patients with severe sepsis or septic shock found mortality benefits with G-CSF therapy; however, these findings are limited by factors such as small sample sizes, selection bias, and lack of an appropriate control group. Prospective, randomized, multicenter, double-blind studies failed to confirm the benefits in mortality for patients receiving G-CSF for the treatment of severe sepsis and septic shock. Due to the limitations in the design of the studies that report a mortality benefit and prospective, randomized, multicenter, double-blind studies that report the lack of a mortality benefit, a recommendation to add G-CSF as an adjunctive therapy in critically ill patients with severe sepsis and septic shock cannot be made at this time.

CONCLUSION

The available data, especially those from large, prospective, randomized, double-blind studies, do not support the use of G-CSF as an adjunct therapy to standard care for critically ill patients with severe sepsis or septic shock. Data from prospective, large, randomized, controlled, well-designed studies are needed to define the optimal G-CSF dosing regimen, the safety of this therapy, and the effects of G-CSF on patient morbidity and survival.

Morbidity and mortality outcomes of cytoreductive surgery and perioperative intraperitoneal chemotherapy at a single tertiary institution: towards a new perspective of this treatment

INTRODUCTION

Cytoreductive surgery (CRS) combined with perioperative intraperitoneal chemotherapy (PIC) is a treatment option for peritoneal surface malignancy. Despite the survival benefits, this treatment was previously associated with a high morbidity and mortality rates and the perception of the poor perioperative outcomes associated with this regimen remains. The aim of this study was to report the perioperative outcomes of CRS and PIC from a single institution to review factors that are associated with a poor perioperative outcome.

METHODS

The clinical- and treatment-related data of 243 consecutive procedures performed were prospectively collected and retrospectively reviewed. Adverse events were rated according to the National Cancer Institute's Common Toxicity Criteria (grade I-V). Univariate and multivariate analyses were performed to identify significant clinical and treatment-related factors for a poor perioperative outcome (grades III/IV/V morbidity).

RESULTS

The perioperative mortality rate was 3%. The rate of severe morbidity was 43%. Multivariate analysis demonstrated that left upper quadrant peritonectomy (P < 0.001) and small bowel resection (P < 0.01) were factors that predicted for a poor perioperative outcome.

CONCLUSIONS

The morbidity and mortality rates of CRS and PIC are within an acceptable range for a major gastrointestinal surgery which is performed with a curative intent. Patient selection is important in ensuring that suitable patients receive this treatment. A new perspective of this treatment needs to be sought.

G-CSF Control of Neutrophils Dynamics in the Blood

White blood cell neutrophil is a key component in the fast initial immune response against bacterial and fungal infections. Granulocyte colony stimulating factor (G-CSF) which is naturally produced in the body, is known to control the neutrophils production in the bone marrow and the neutrophils delivery into the blood. In oncological practice, G-CSF injections are widely used to treat neutropenia (dangerously low levels of neutrophils in the blood) and to prevent the infectious complications that often follow chemotherapy. However, the accurate dynamics of G-CSF neutrophil interaction has not been fully determined and no general scheme exists for an optimal G-CSF application in neutropenia. Here we develop a two-dimensional ordinary differential equation model for the G-CSF-neutrophil dynamics in the blood. The model is built axiomatically by first formally defining from the biology the expected properties of the model, and then deducing the dynamic behavior of the resulting system. The resulting model is structurally stable, and its dynamical features are independent of the precise form of the various rate functions. Choosing a specific form for these functions, three complementary parameter estimation procedures for one clinical (training) data set are utilized. The fully parameterized model (6 parameters) provides adequate predictions for several additional clinical data sets on time scales of several days. We briefly discuss the utility of this relatively simple and robust model in several clinical conditions.

Morphologic and quantitative analyses of leukocytes in patients with multiple system trauma

Multiple system trauma can occur in accidents, natural disasters, and deliberate attacks, and vital areas of the body, such as the head, chest, and abdomen, may be affected. Investigators in the present study sought to examine morphologic and morphometric alterations of leukocyte responses in patients with multiple trauma during the first 4 h after a traumatic event. Venous blood samples were drawn from 51 patients, 30 male and 21 female, aged 16 to 59 y. The number of leukocytes increased significantly in all patients, but no significant differences were noted between the male and female groups. Complete blood counts revealed normal ratios of leukocyte types. It is suggested that in patients who have experienced multiple trauma, aggressive antibiotic therapy should be initiated to prevent posttraumatic infection and to protect against secondary organ failure.

Comparative effects of early randomized immune or non-immune-enhancing enteral nutrition on cytokine production in children with septic shock

OBJECTIVE

To compare the effect of early enteral feeding using immune-enhancing (IE) vs. non-immune-enhancing (NIE) formulas on cytokines in children with septic shock.

DESIGN AND SETTING

A single-center, randomized, blinded controlled trial in a pediatric intensive care unit of a university hospital.

PATIENTS

We randomized 38 patients with septic shock to either IE or NIE. Feedings were advanced to a target volume of energy intake equal to 1/2, 1, 5/4, 6/4, and 6/4 of the predicted basal metabolic rate on days 1-5, respectively.

MEASUREMENTS AND RESULTS

Interleukins (IL) 1beta, 6, and 8, tumor necrosis factor alpha, C-reactive protein, Pediatric Risk of Mortality (PRISM) score, survival, secondary infections, length of stay, and mechanical ventilation were compared within and between the two groups. Actual mean energy and protein intakes did not differ between the two groups and the caloric-protein balance was not correlated to cytokine levels. On day 5 IL-6 levels were significantly lower (11.8+/-2.4 vs. 38.3+/-3.6) and IL-8 significantly higher in the IE than in the NIE group (65.4+/-17 vs. 21+/-2.5). After 5 days of nutritional support a significant decrease in IL-6 levels was recorded only in group IE (mean of paired differences 39.4+/-3 pg/ml). In multivariate regression analysis the variation in cytokines was independently correlated only to PRISM (R(2)=-0.50), but pediatric intensive care unit outcome endpoints did not differ between the two groups.

CONCLUSIONS

Early IE nutrition may modulate cytokines in children with septic shock, but there is no evidence that this immunomodulation has any impact on short-term outcome.

Is there a place for granulocyte colony-stimulating factor in non-neutropenic critically ill patients?

Immunoparalysis, characterised by impairments in neutrophil and monocyte/macrophage function, is common in critically ill patients. The theoretical ability of granulocyte colony-stimulating factor (G-CSF) to improve the functions of both neutrophils and monocytes/macrophages provides a rationale for G-CSF therapy in non-neutropenic critically ill patients with infection or a high risk of nosocomial infection. The expression of the receptors that mediate G-CSF effects in neutrophils and monocytes/macrophages is regulated by bacterial products, cytokines and endogenous G-CSF levels, accounting for the variables effects of G-CSF on the neutrophil functions of critically ill patients. This variability should be taken into account when designing studies on the use of G-CSF in ICU-patients. Studies are still needed to identify the subset of patients who may benefit from G-CSF therapy.