Rob H.J. Beelen

Expression of MCP-1 by Reactive Astrocytes in Demyelinating Multiple Sclerosis Lesions

The pathology of multiple sclerosis (MS) is characterized by breakdown of the blood-brain barrier (BBB), accompanied by infiltration of macrophages and T lymphocytes into the central nervous system (CNS). The migration of these cells into the CNS parenchyma may be partly regulated by chemokines. The aim of this study was therefore to investigate the cellular localization of the potent monocyte- and T-cell-attracting chemokine monocyte chemoattractant protein (MCP)-1 by immunohistochemistry on postmortem brain tissue from MS and normal control cases. Brain tissue samples of six MS patients and four patients without a history of brain disease were neuropathologically classified according to characteristic (immuno)histochemical staining patterns. Frozen tissue sections of active demyelinating MS lesions, chronic active demyelinating MS lesions, and normal control brain were immunohistochemically stained with a monoclonal antibody directed against MCP-1. In active demyelinating MS lesions as well as in chronic active MS lesions, reactive hypertrophic astrocytes were strongly immunoreactive for MCP-1, whereas perivascular and parenchymal foamy macrophages did not express MCP-1 protein. These results suggest a significant role for the beta-chemokine MCP-1, synthesized in vivo by reactive hypertrophic astrocytes, in the recruitment and activation of myelin-degrading macrophages and thereby contributing to the evolution of MS lesions.

Macrophage subpopulations in the mouse spleen renewed by local proliferation.

A dual origin, by both immigration of blood monocytes and local proliferation has been reported for macrophages, which are heterogeneous in several aspects. Until now few studies have focussed on renewal of macrophages. Therefore, in this study macrophage renewal by local proliferation has been studied in the spleen. Spleen tissue of mice which had received BrdU intravenously was investigated immunohistochemically to detect BrdU incorporated by macrophages. BrdU incorporation by splenic macrophages was studied under steady state conditions as well as during repopulation after experimental macrophage depletion. Under steady state conditions, BrdU incorporation was found in 3.0 +/- 0.5% of the white pulp macrophages and in approximately 1% of the metallophilic macrophages only. Comparable results were found during repopulation after experimental macrophage depletion. The data suggest that renewal of macrophages by local proliferation is restricted to certain subsets in the spleen and that the macrophage subsets of the spleen are renewed by different mechanisms, or belong to different lineages of macrophage differentiation.

Stress management training for breast cancer surgery patients

This study evaluated the psychological effects of a pre‐surgical stress management training (SMT) in cancer patients.

Bactericidal/Permeability-Increasing Protein Preserves Leukocyte Functions After Major Liver Resection

ObjectiveTo analyze postoperative leukocyte functions in patients undergoing hemihepatectomy, and to assess the effect of treatment with the endotoxin-neutralizing agent bactericidal/permeability-increasing protein (rBPI21). Summary Background DataExtensive liver resection is associated with a high incidence of infectious complications. Because elimination of pathogenic microorganisms occurs mainly by leukocytes, this increased rate of infections is most likely due to an impaired function of these cells. Endotoxin, translocated from the gut into the systemic circulation as a result of increased gut permeability and reduced hepatic clearance function after major liver resection, may play an important role in the impairment of posthepatectomy leukocyte function. MethodsTo investigate whether hemihepatectomy results in impaired leukocyte functions and to determine the role of endotoxin in this process, leukocyte oxidative burst and leukocyte antigen expression were studied in three groups of patients: patients undergoing a hemihepatectomy and receiving rBPI21 treatment, patients undergoing hemihepatectomy and receiving placebo, and as an extra control group patients undergoing other major abdominal surgeries. Blood samples were collected before surgery, 2 hours after surgery, and at days 1, 2, 5, and 7. Phorbol myristate acetate-stimulated oxidative burst was measured using dihydrorhodamine, and leukocyte surface expression of the antigens CD11b, CD16, and CD14 was investigated by indirect immunofluorescence. Both oxidative burst and membrane surface expression were quantified by flow cytometry. An indication of the antiendotoxin effect of rBPI21 treatment was provided by assessment of plasma lipopolysaccharide binding protein (LBP) levels by enzyme-linked immunosorbent assay. ResultsThe oxidative burst in the hemihepatectomized patients receiving placebo and the controls increased 2 hours after surgery, whereas it decreased in the rBPI21-treated patients, resulting in significant differences between the groups. On day 1, neutrophil CD11b expression and monocyte CD14 expression in the rBPI21-treated patients and controls were significantly lower than in the placebo group. At 2 hours, CD16 expression in the placebo-treated patients was significantly higher than in the rBPI21-treated patients and controls. On day 5 and day 7, plasma LBP levels were significantly higher in the placebo-treated patients compared with the rBPI21-treated patients. ConclusionsThe results of this study show that patients undergoing major liver resection have an increased activation of leukocytes compared with those undergoing other major abdominal surgery. This enhanced activation may contribute to the increased risk of infection in these patients. Administration of the endotoxin-neutralizing agent rBPI21 to hemihepatectomy patients was shown to reduce plasma LBP levels, to preserve leukocyte functions partially, and to reduce leukocyte activation to the level of other, nonhepatic abdominal surgery.

Macrophage phenotype regulation by colony-stimulating factors at bone marrow level

Macrophages (mφs) can be divided into several subpopulations, which differ in phenotype, function, and localization patterns. However, little is known about the mechanisms that regulate this heterogeneity. We investigated whether mφ heterogeneity is regulated by colony‐stimulating factors (CSFs) at the bone marrow level. By clonal expansion of bone marrow‐derived precursor cells in die presence of CSF‐1, granulocyte‐macrophage CSF or multi‐CSF (interleukin‐3), phenotypic heterogeneity was observed between mφ colonies. Heterogeneity was found especially when different CSF culture conditions were used but also between mφ colonies derived under the same CSF culture condition. Our results illustrate that CSFs from the bone marrow hemopoietic microenvironment are important for the induction of phenotypic heterogeneity within the progeny of cloned mφ precursor cells during maturation and differentiation in vitro.

Chronic inflammation induces the expression of dendritic cell markers not related to functional antigen presentation on peritoneal exudate macrophages.

Phenotypic heterogeneity between macrophages in situ has been reported, using different macrophage-specific monoclonal antibodies. Microenvironmental factors, which may play an important role in inducing this heterogeneity were studied in a local inflammatory response in vivo. Our results show that peritoneal exudate macrophages, formed during Thioglycollate induced chronic inflammation, acquire expression of the dendritic cell markers NLDC-145 and 6D2. In contrast to these phenotypic characteristics, NLDC-145+/6D2+ exudate cells do not function like dendritic cells in an allogeneic-MLR, but are suppressive when compared with steady state peritoneal cells. The expression of these membrane markers on exudate cells is discussed.