Granulocyte colony-stimulating factor does not enhance phagocytosis or microbicidal activity of human mature polymorphonuclear neutrophils in vitro

Granulocyte colony-stimulating factor for the treatment of biomaterial-associated staphylococcal infections in-vitro

Staphylococcal infections are a common and severe complication after the implantation of a prosthesis. We developed an in-vitro model for biomaterial-associated infections and studied the effects of human recombinant granulocyte colony-stimulating factor (rhuG-CSF; filgrastime) on the eradication of bacteria from the surface of biomaterial. Latex beads (25 micro m) were incubated with 10(7) colony forming units of either a slime producing (DSM 3269) or non-slime producing strain (ATCC 14990) of Staphylococcus epidermidis. Infected particles were consecutively confronted with effector cells, derived from heparinized whole blood samples taken from healthy volunteers, after stimulation with rhuG-CSF (5,000 IU/ml, 10,000 IU/ml). Control blood specimens were not stimulated or conditioned with normal saline. The results indicate that stimulation with rhuG-CSF induced an increased rate of phagocytosis and lead to a more rapid reduction of adhering bacteria from the surface of the beads. Therefore, the in-vitro data suggest that patients with prosthesis infection may profit from an additional treatment with rhuG-CSF.

Neutropenia, neutrophil dysfunction, and bacterial infection in patients with human immunodeficiency virus disease: the role of granulocyte colony-stimulating factor

Neutropenia frequently complicates infection due to human immunodeficiency virus (HIV). The etiology of neutropenia in this setting includes bone marrow infection or infiltration, myelosuppressive therapies, the presence of antibodies to HIV, and accelerated apoptosis. Protection against microbial invaders by neutrophils is further compromised by impaired chemotaxis and phagocytosis, production of toxic oxygen species, and expression of cellular adhesion molecules. Neutropenia is a significant risk factor for bacterial infection in HIV-infected patients. Endogenous cytokines, such as granulocyte colony-stimulating factor (G-CSF) and granulocyte-macrophage colony-stimulating factor, regulate neutrophil count and function. Treatment with recombinant human methionyl G-CSF (filgrastim) has lessened neutropenia in patients with HIV infection. Clinical trials have shown that the incidence of bacterial infections and the number of consequent days of hospitalization for HIV-infected patients receiving filgrastim therapy are lower. Filgrastim treatment also allows administration of larger doses of myelosuppressive agents.

Granulocyte-macrophage colony-stimulating factor (GM-CSF)-coated implants and their potential for reducing biomaterial-associated infection in neutropenic hosts

The incidence of infections associated with the use of medical biomaterials is high for skin-penetrating devices, when microbes of the normal skin flora like coagulase-positive and coagulase-negative staphylococci dominate as causative organisms. The most serious ones are infections in immunocompromised individuals. A mouse model of subcutaneous staphylococcal infection yielding abscesses in cyclophosphamide-induced neutropenic mice implanted with heparinized polyethylene (H-PE) was used. The present study addresses the question of the effects of implant modification with recombinant granulocyte-macrophage stimulating factor (rGM-CSF) on the course of infection. Our findings demonstrate that such modification reduces the proliferation of bacteria within the abscess and as a consequence limits the dissemination of bacteria from the local infection induced in the neutropenic host.

Effects of granulocyte-macrophage colony stimulating factor (GM-CSF) on biomaterial-associated staphylococcal infection in mice

Staphylococcal infections are a major complication in the usage of biomaterials. Different modifications of polymers have been made to reduce the incidence of such infections. We studied the effects of modifying heparinized polyethylene (H-PE) with mouse recombinant granulocyte-macrophage stimulating factor (rGM-CSF). The elimination of staphylococci (Staphylococcus aureus, S. epidermidis) from the peritoneum of mice implanted with rGM-CSF-coated H-PE was slightly more effective than the elimination of the bacteria from the peritoneum of animals implanted with uncoated H-PE. Most interestingly, the number of staphylococci present in the biofilms covering rGM-CSF-coated implants were significantly lower than the number of bacteria detected on the surface of H-PE not coated with rGM-CSF. In vitro, rGM-CSF restored the anti-bacterial potency of the phagocytes, which had been reduced by surface contact with H-PE. The results suggest that modification of biomaterials with rGM-CSF could be one way of preventing staphylococcal infections; especially in neutropenic disorders, which constitute the highest risk factor for foreign body-associated infections.