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Arteriosclerosis, Thrombosis, and... Jun 2005Apoptotic cell death has been demonstrated in advanced human atherosclerotic plaques. Apoptotic cells (ACs) should be rapidly removed by macrophages, otherwise secondary...
OBJECTIVE
Apoptotic cell death has been demonstrated in advanced human atherosclerotic plaques. Apoptotic cells (ACs) should be rapidly removed by macrophages, otherwise secondary necrosis occurs, which in turn elicits inflammatory responses and plaque progression. Therefore, we investigated the efficiency of phagocytosis of ACs by macrophages in atherosclerosis.
METHODS AND RESULTS
Human endarterectomy specimens and human tonsils were costained for CD68 (macrophages) and terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling (TUNEL) (apoptosis). Free and phagocytized ACs were counted in both tissues. The ratio of free versus phagocytized AC was 19-times higher in human atherosclerotic plaques as compared with human tonsils, indicating a severe defect in clearance of AC. Impaired phagocytosis of AC was also detected in plaques from cholesterol-fed rabbits and did not further change with plaque progression. In vitro experiments with J774 or peritoneal mouse macrophages showed that several factors caused impaired phagocytosis of AC including cytoplasmic overload of macrophages with indigestible material (beads), free radical attack, and competitive inhibition among oxidized red blood cells, oxidized low-density lipoprotein and ACs for the same receptor(s) on the macrophage.
CONCLUSIONS
Our data demonstrate that phagocytosis of ACs is impaired in atherosclerotic plaques, which is at least partly attributed to oxidative stress and cytoplasmic saturation with indigestible material.
Topics: Aged; Animals; Apoptosis; Carotid Artery Diseases; Cytoplasm; Erythrocytes; Female; Humans; Lipoproteins, LDL; Macrophages, Peritoneal; Male; Mice; Necrosis; Oxidative Stress; Palatine Tonsil; Phagocytosis; Rabbits; U937 Cells
PubMed: 15831805
DOI: 10.1161/01.ATV.0000166517.18801.a7 -
Respiration; International Review of... 2011Pseudomonas aeruginosa is a cause of infections of the lower respiratory tract among patients with chronic lung disorders. It is questionable whether virulence of this... (Comparative Study)
Comparative Study
BACKGROUND
Pseudomonas aeruginosa is a cause of infections of the lower respiratory tract among patients with chronic lung disorders. It is questionable whether virulence of this species may be influenced by multidrug resistance (MDR).
OBJECTIVES
To define the impact of MDR in experimental lung infection.
METHODS
Experimental empyema was induced in rabbits by MDR (group A, n = 16) and by susceptible isolates (group B, n = 10). Pleural fluid was sampled for quantitative culture and estimation of cell apoptosis and of tumor necrosis factor-alpha (TNFα) and malondialdehyde (MDA). Survival was recorded. Cytokine production was stimulated in U937 monocytes by samples of pleural fluid. Whole blood of rabbits was incubated with the isolates; induction of apoptosis was assessed.
RESULTS
Survival of group A was prolonged compared to group B. This was accompanied by lower bacterial counts of the inoculated pathogens in pleural fluid and in the lungs of group A compared with group B. Early apoptosis of neutrophils of pleural fluid of group A was lower compared with group B. Pleural fluid concentrations of TNFα and MDA did not differ between the groups. Cytokine production by U937 monocytes after stimulation with pleural fluid was greater in group B than in group A. The susceptible isolate induced apoptosis of neutrophils in vitro at a greater rate than the MDR isolate.
CONCLUSIONS
Experimental empyema by susceptible P. aeruginosa is accompanied by greater mortality compared with MDR P. aeruginosa. This phenomenon may be attributed to the different growth pattern of the pathogens or to their interaction with the innate immune system.
Topics: Animals; Bacterial Load; Cytokines; Disease Susceptibility; Drug Resistance, Multiple, Bacterial; Empyema; Humans; Immunity, Innate; Lung; Male; Malondialdehyde; Monocytes; Neutrophils; Pleural Effusion; Pseudomonas Infections; Pseudomonas aeruginosa; Rabbits; Species Specificity; Survival Rate; Tumor Necrosis Factor-alpha; U937 Cells; Virulence
PubMed: 21525725
DOI: 10.1159/000326893 -
Microbial Pathogenesis Feb 2004Legionnaire's disease is caused by the intracellular pathogen Legionella pneumophila, presenting as an acute pneumonia. Attachment is the key step during infection,...
Legionnaire's disease is caused by the intracellular pathogen Legionella pneumophila, presenting as an acute pneumonia. Attachment is the key step during infection, often relying on an interaction between host cell oligosaccharides and bacterial adhesins. Inhibition of this interaction by receptor mimics offers possible novel therapeutic treatments. L. pneumophila attachment to the A549 cell line was significantly reduced by treatment with tunicamycin (73.6%) and sodium metaperiodate (63.7%). This indicates the importance of cell surface oligosaccharide chains in adhesion. A number of putative anti-adhesion compounds inhibited attachment to the A549 and U937 cell lines. The most inhibitory compounds were polymeric saccharides, GalNAcbeta1-4Gal, Galbeta1-4GlcNAc and para-nitrophenol. These compounds inhibited adhesion to a range of human respiratory cell lines, including nasal epithelial, bronchial epithelial and alveolar epithelial cell lines and the human monocytic cell line, U937. Some eukaryotic receptors for L. pneumophila were determined to be the glycolipids, asialo-GM1 and asialo-GM2 that contain the inhibitory saccharide moiety, GalNAcbeta1-4Gal. The identified compounds have the potential to be used as novel treatments for Legionnaire's disease.
Topics: Adhesins, Bacterial; Anti-Bacterial Agents; Bacterial Adhesion; Cell Line; Colony Count, Microbial; Epithelial Cells; G(M1) Ganglioside; Gangliosides; Glycolipids; Glycosphingolipids; Humans; Kinetics; Legionella pneumophila; Molecular Sequence Data; Monocytes; Oligosaccharides; Periodic Acid; Receptors, Cell Surface; Respiratory Mucosa; Time Factors; Tunicamycin; U937 Cells
PubMed: 14687561
DOI: 10.1016/j.micpath.2003.09.004 -
Journal of Controlled Release :... Jun 2011The objective of this study was to determine the effect of systemic delivery of prednisolone phosphate (PLP) encapsulated within long circulating 'stealth' liposomes on...
UNLABELLED
The objective of this study was to determine the effect of systemic delivery of prednisolone phosphate (PLP) encapsulated within long circulating 'stealth' liposomes on bone erosion and osteoclast activity during experimental antigen-induced arthritis (AIA). Liposomal PLP strongly suppressed knee joint swelling, synovial infiltrate and bone erosion in antigen-induced arthritis. The number of active osteoclasts was not only suppressed in bone lesions near inflamed synovium, but also within the trabecular bone of the tibia, suggesting a systemic suppression of osteoclast activation. Furthermore, liposomal PLP directly blocked osteoclast differentiation and bone resorption in vitro while it also suppressed expression of osteoclast differentiation factors M-CSF and RANKL in the synovium. Targeting studies showed that liposomes are most efficiently phagocytosed by macrophages and early precursors of osteoclasts in the bone marrow rather than by mature osteoclasts, indicating a possible inhibition of osteoclast differentiation from an early stage.
CONCLUSION
Liposomal glucocorticoid delivery rather than free PLP offers a more efficacious way to inhibit both inflammation and bone erosion in rheumatoid arthritis.
Topics: 1,2-Dipalmitoylphosphatidylcholine; Acid Phosphatase; Adjuvants, Immunologic; Animals; Arthritis, Experimental; Bone Marrow; Bone Marrow Cells; Bone Resorption; Cathepsin K; Cell Count; Cell Differentiation; Cholesterol; Down-Regulation; Glucocorticoids; Isoenzymes; Knee Joint; Liposomes; Macrophage Colony-Stimulating Factor; Mice; Mice, Inbred C57BL; Monocyte-Macrophage Precursor Cells; Osteoclasts; Phagocytosis; Phosphatidylethanolamines; Polyethylene Glycols; Prednisolone; RANK Ligand; Receptor Activator of Nuclear Factor-kappa B; Serum Albumin, Bovine; Synovial Membrane; Synovitis; Tartrate-Resistant Acid Phosphatase; Vaccination
PubMed: 21396411
DOI: 10.1016/j.jconrel.2011.03.001 -
International Journal of Oncology Oct 2010We have previously shown that peritoneal macrophages from mice bearing advanced D1-DMBA3 mammary tumors are impaired in their inflammatory functions but are not...
We have previously shown that peritoneal macrophages from mice bearing advanced D1-DMBA3 mammary tumors are impaired in their inflammatory functions but are not alternatively activated either and are less differentiated than the ones from normal mice. However, little is known about whether similar defects exist in their precursor stages as blood monocytes. We examined if blood monocytes from mammary tumor-bearing mice are already altered in their activation profiles before becoming macrophages and whether they correspond to inflammatory or resident monocyte subtypes. Much effort is currently devoted to reversing macrophage adverse traits in tumor hosts; as these cells reside within tissues, access is limited. Blood monocytes could be better targeted and manipulated by less invasive means. In the present study, mononuclear cells were isolated from whole blood of D1-DMBA-3 mammary tumor-bearing and normal BALB/c mice and CD115(+) monocytes were analyzed. Our results show that there is an increase in circulating monocytes in tumor hosts; these monocytes exhibit a reduced expression of several myeloid differentiation markers such as CD115, F4/80, CD68 and CD11b. Moreover, downregulation of MHC II, CD62L and the proangiogenic marker Tie-2 are observed in these cells, whereas Gr-1 and Ly6C are upregulated. Furthermore, gene microarray analysis performed for the first time in blood monocytes from tumor hosts indicates that they express a mixture of pro-inflammatory and anti-inflammatory cytokines and chemokines. Interestingly, CCR2 and CX3CR1, which are crucial in monocyte definition as inflammatory or resident, respectively, are both upregulated. Importantly, complement proteins are enhanced whereas nitric oxide production is decreased and there is no measurable arginase activity detected in these cells. Collectively, our study represents the first comprehensive analysis of blood monocytes from tumor-bearing mice; we conclude that these cells are neither completely inflammatory nor suppressive and are less differentiated, similar to the macrophages they later become.
Topics: Adenocarcinoma; Animals; Antigens, CD; Antigens, Differentiation; Antigens, Differentiation, Myelomonocytic; Antigens, Ly; Arginase; CD11b Antigen; Cell Differentiation; Cell Separation; Cells, Cultured; Chemokines; Complement System Proteins; Cytokines; Female; Gene Expression Profiling; Gene Expression Regulation, Neoplastic; Histocompatibility Antigens Class II; Immunophenotyping; Inflammation Mediators; L-Selectin; Leukocyte Count; Mammary Neoplasms, Experimental; Mice; Mice, Inbred BALB C; Monocytes; Nitric Oxide; Receptor Protein-Tyrosine Kinases; Receptor, Macrophage Colony-Stimulating Factor; Receptor, TIE-2; Tumor Escape
PubMed: 20811711
DOI: 10.3892/ijo_00000740 -
European Journal of Cancer & Clinical... Aug 1987In acute myeloid leukaemia the peripheral leukocyte count is known to be a prognostic factor. The preserved capacity of leukaemic cells to mature has also been suggested...
In acute myeloid leukaemia the peripheral leukocyte count is known to be a prognostic factor. The preserved capacity of leukaemic cells to mature has also been suggested to be one. In a series of 179 cases of adult acute myeloid leukaemia peripheral leukaemic cell count and degree of maturation were found to be inversely correlated. As the degree of maturation of leukaemic cells in peripheral blood was lower than that in bone marrow in the majority of cases, blast cells appear to be released more easily from the marrow than cells that have matured to some extent in the direction of the larger promyelocytic or promonocytic cell type. In a series of 35 cases we found peripheral blast cells to be smaller than those in bone marrow. Moreover, central blast cell diameter and peripheral leukaemic cell count were inversely correlated. Therefore, leukaemic cell size or some factor related to it may contribute to the preferential egress of small immature cells from the marrow. Differences in proliferative activity could not account for the inverse correlation between degree of maturation and leukaemic cell count.
Topics: Adult; Bone Marrow; Granulocytes; Humans; Leukemia, Myeloid, Acute; Leukocyte Count; Leukocytes; Mitosis; Prognosis
PubMed: 3477465
DOI: 10.1016/0277-5379(87)90144-1 -
Blood May 2011CCAAT/enhancer binding protein-α (CEBPA) mutations in acute myeloid leukemia (AML) patients with a normal karyotype (NK) confer favorable prognosis, whereas NK-AML...
CCAAT/enhancer binding protein-α (CEBPA) mutations in acute myeloid leukemia (AML) patients with a normal karyotype (NK) confer favorable prognosis, whereas NK-AML patients per se are of intermediate risk. This suggests that blocked CEBPA function characterizes NK-AML with favorable outcome. We determined the prognostic significance of CEBPA DNA binding function by enzyme-linked immunosorbent assay in 105 NK-AML patients. Suppressed CEBPA DNA binding was defined by 21 good-risk AML patients with inv(16) or t(8;21) (both abnormalities targeting CEBPA) and 8 NK-AML patients with dominant-negative CEBPA mutations. NK-AML patients with suppressed CEBPA function showed a better overall survival (P = .0231) and disease-free survival (P = .0069) than patients with conserved CEBPA function. Suppressed CEBPA DNA binding was an independent marker for better overall survival and disease-free survival in a multivariable analysis that included FLT3-ITD, NPM1 and CEBPA mutation status, white blood cell count, age and lactate dehydrogenase. These data indicate that suppressed CEBPA function is associated with favorable prognosis in NK-AML patients.
Topics: Adolescent; Adult; Aged; Base Sequence; CCAAT-Enhancer-Binding Proteins; Core Binding Factor Alpha 2 Subunit; DNA, Neoplasm; Female; Humans; Kaplan-Meier Estimate; Karyotyping; Leukemia, Myeloid, Acute; Male; Middle Aged; Mutation; Nucleophosmin; Oncogene Proteins, Fusion; Prognosis; RNA, Messenger; RNA, Neoplasm; RUNX1 Translocation Partner 1 Protein; U937 Cells; Young Adult
PubMed: 21389317
DOI: 10.1182/blood-2010-11-320747 -
Journal of Ultrasound in Medicine :... Dec 2017Low-intensity pulsed ultrasound (US) has been reported to promote periodontal tissue regeneration and reduce inflammation in soft tissues and in bone infectious...
OBJECTIVES
Low-intensity pulsed ultrasound (US) has been reported to promote periodontal tissue regeneration and reduce inflammation in soft tissues and in bone infectious diseases. Here we investigated the effect of low-intensity pulsed US on the expression of lipopolysaccharide (LPS)-induced inflammatory factors in U937 macrophage cells.
METHODS
U937 cells were stimulated with different concentrations of LPS and exposed to different intensities of low-intensity pulsed US. Cell viability and apoptosis of U937 cells were determined by cell-counting kit assays and flow cytometry. A real-time polymerase chain reaction and an enzyme-linked immunosorbent assay were used to test the expression of inflammatory factors. The expression levels of toll-like receptor 4, p65, p-IκBα, and IκBα were assessed by western blots.
RESULTS
Tumor necrosis factor α began to increase in U937 cells on induction with 1-μg/mL LPS. Low-intensity pulsed US at the intensity of 60 mW/cm was more effective in reducing interleukin 8 (IL-8) expression. Furthermore, LPS inhibited the viability and increased apoptosis of U937 cells, whereas low-intensity pulsed US significantly reversed these effects (P < .05). Low-intensity pulsed US reduced the protein expression of IL-6 and IL-8 at both gene and protein levels in U937 cells. The western blot and immunofluorescence showed that low-intensity pulsed US primarily suppressed the degradation and phosphorylation of IκBα and the translocation of p65 into the nuclei.
CONCLUSIONS
Low-intensity pulsed US alleviated the expression of inflammatory factors induced by LPS in U937 cells. This process was modulated by suppressing the toll-like receptor 4-nuclear factor κB signaling pathway. Therefore, low-intensity pulsed US might be a potential immunomodulatory therapy for the treatment of periodontitis.
Topics: Apoptosis; Cell Survival; Cells, Cultured; Enzyme-Linked Immunosorbent Assay; Flow Cytometry; Humans; Inflammation; Lipopolysaccharides; Real-Time Polymerase Chain Reaction; U937 Cells; Ultrasonic Therapy; Ultrasonic Waves
PubMed: 28600899
DOI: 10.1002/jum.14239 -
International Journal of Radiation... Aug 2015Radiation-induced heart disease (RIHD) is a delayed effect of radiotherapy for cancers of the chest, such as breast, esophageal, and lung. Kinins are small peptides with...
PURPOSE
Radiation-induced heart disease (RIHD) is a delayed effect of radiotherapy for cancers of the chest, such as breast, esophageal, and lung. Kinins are small peptides with cardioprotective properties. We previously used a rat model that lacks the precursor kininogen to demonstrate that kinins are involved in RIHD. Here, we examined the role of the kinin B2 receptor (B2R) in early radiation-induced signaling in the heart.
MATERIALS AND METHODS
Male Brown Norway rats received the B2R-selective antagonist HOE-140 (icatibant) via osmotic minipump from 5 days before until 4 weeks after 21 Gy local heart irradiation. At 4 weeks, signaling events were measured in left ventricular homogenates and nuclear extracts using western blotting and real-time polymerase chain reaction. Numbers of CD68-positive (monocytes/macrophages), CD2-positive (T-lymphocytes), and mast cells were measured using immunohistochemistry.
RESULTS
Radiation-induced c-Jun phosphorylation and nuclear translocation were enhanced by HOE-140. HOE-140 did not modify endothelial nitric oxide synthase (eNOS) phosphorylation or alter numbers of CD2-positive or mast cells, but enhanced CD68-positive cell counts in irradiated hearts.
CONCLUSIONS
B2R signaling may regulate monocyte/macrophage infiltration and c-Jun signals in the irradiated heart. Although eNOS is a main target for kinins, the B2R may not regulate eNOS phosphorylation in response to radiation.
Topics: Animals; Heart; Heart Diseases; Male; Myocardium; Radiation Dosage; Radiation Injuries; Radiotherapy; Rats; Receptor, Bradykinin B2
PubMed: 25955317
DOI: 10.3109/09553002.2015.1047041 -
The Journal of Pharmacology and... Nov 2012Levels of circulating angiopoietin-2 (Ang-2) increase in sepsis, raising the possibility that Ang-2 acts as a modulator in the sepsis cascade. To investigate this,...
Levels of circulating angiopoietin-2 (Ang-2) increase in sepsis, raising the possibility that Ang-2 acts as a modulator in the sepsis cascade. To investigate this, experimental sepsis was induced in male C57BL6 mice by a multidrug-resistant isolate of Pseudomonas aeruginosa; survival was determined along with neutrophil tissue infiltration and release of proinflammatory cytokines. Survival was significantly increased either by pretreatment with recombinant Ang-2 2 h before or treatment with recombinant Ang-2 30 min after bacterial challenge. Likewise, Ang-2 pretreatment protected against sepsis-related death elicited by Escherichia coli; however, Ang-2 failed to provide protection in lipopolysaccharide (LPS)-challenged mice. The survival advantage of Ang-2 in response to P. aeruginosa challenge was lost in tumor necrosis factor (TNF)-deficient mice or neutropenic mice. Infiltration of the liver by neutrophils was elevated in the Ang-2 group compared with saline-treated animals. Serum TNF-α levels were reduced by Ang-2, whereas those of interleukin (IL)-6 and IL-10 remained unchanged. This was accompanied by lower release of TNF-α by stimulated splenocytes. When applied to U937 cells in vitro, heat-killed P. aeruginosa induced the secretion of IL-6 and TNF-α; low levels of exogenous TNF-α synergized with P. aeruginosa. This synergistic effect was abolished after the addition of Ang-2. These results put in evidence a striking protective role of Ang-2 in experimental sepsis evoked by a multidrug-resistant isolate of P. aeruginosa attributed to modulation of TNF-α production and changes in neutrophil migration. The protective role of Ang-2 is shown when whole microorganisms are used and not LPS, suggesting complex interactions with the host immune response.
Topics: Angiopoietin-2; Animals; Apoptosis; Capillary Permeability; Cell Count; Colony-Forming Units Assay; Cytokines; Drug Resistance, Multiple, Bacterial; Enzyme Inhibitors; Escherichia coli; Humans; Mice; Mice, Inbred C57BL; Mice, Knockout; Neutrophils; Peritoneal Cavity; Pseudomonas Infections; Pseudomonas aeruginosa; Sepsis; Spleen; Survival Analysis; Tumor Necrosis Factor-alpha; U937 Cells
PubMed: 22859861
DOI: 10.1124/jpet.112.195180