Effects of nano particles on antigen-related airway inflammation in mice

BACKGROUND: Particulate matter (PM) can exacerbate allergic airway diseases. Although health effects of PM with a diameter of less than 100 nm have been focused, few studies have elucidated the correlation between the sizes of particles and aggravation of allergic diseases. We investigated the effects of nano particles with a diameter of 14 nm or 56 nm on antigen-related airway inflammation. METHODS: ICR mice were divided into six experimental groups. Vehicle, two sizes of carbon nano particles, ovalbumin (OVA), and OVA + nano particles were administered intratracheally. Cellular profile of bronchoalveolar lavage (BAL) fluid, lung histology, expression of cytokines, chemokines, and 8-hydroxy-2'-deoxyguanosine (8-OHdG), and immunoglobulin production were studied. RESULTS: Nano particles with a diameter of 14 nm or 56 nm aggravated antigen-related airway inflammation characterized by infiltration of eosinophils, neutrophils, and mononuclear cells, and by an increase in the number of goblet cells in the bronchial epithelium. Nano particles with antigen increased protein levels of interleukin (IL)-5, IL-6, and IL-13, eotaxin, macrophage chemoattractant protein (MCP)-1, and regulated on activation and normal T cells expressed and secreted (RANTES) in the lung as compared with antigen alone. The formation of 8-OHdG, a proper marker of oxidative stress, was moderately induced by nano particles or antigen alone, and was markedly enhanced by antigen plus nano particles as compared with nano particles or antigen alone. The aggravation was more prominent with 14 nm of nano particles than with 56 nm of particles in overall trend. Particles with a diameter of 14 nm exhibited adjuvant activity for total IgE and antigen-specific IgG(1 )and IgE. CONCLUSION: Nano particles can aggravate antigen-related airway inflammation and immunoglobulin production, which is more prominent with smaller particles. The enhancement may be mediated, at least partly, by the increased local expression of IL-5 and eotaxin, and also by the modulated expression of IL-13, RANTES, MCP-1, and IL-6

Particulate air pollution, systemic oxidative stress, inflammation, and atherosclerosis

Air pollution has been associated with significant adverse health effects leading to increased overall morbidity and mortality of worldwide significance. Epidemiological studies have shown that the largest portion of air pollution-related mortality is due to cardiovascular diseases, predominantly those of ischemic nature. Human studies suggest an association with atherosclerosis and increasing experimental animal data support that this association is likely to be causal. While both gasses and particles have been linked to detrimental health effects, more evidence implicates the particulate matter (PM) components as major responsible for a large portion of the proatherogenic effects. Multiple experimental approaches have revealed the ability of PM components to trigger and/or enhance free radical reactions in cells and tissues, both ex vivo as well as in vivo. It appears that exposure to PM leads to the development of systemic prooxidant and proinflammatory effects that may be of great importance in the development of atherosclerotic lesions. This article reviews the epidemiological studies, experimental animal, and cellular data that support the association of air pollutants, especially the particulate components, with systemic oxidative stress, inflammation, and atherosclerosis. It also reviews the use of transcriptomic studies to elucidate molecular pathways of importance in those systemic effects

Ultrafine particles affect the balance of endogenous pro- and anti-inflammatory lipid mediators in the lung: in-vitro and in-vivo studies.

Exposure to ultrafine particles exerts diverse harmful effects including aggravation of pulmonary diseases like asthma. Recently we demonstrated in a mouse model for allergic airway inflammation that particle-derived oxidative stress plays a crucial role during augmentation of allergen-induced lung inflammation by ultrafine carbon particle (UfCP) inhalation. The mechanisms how particle inhalation might change the inflammatory balance in the lungs, leading to accelerated inflammatory reactions, remain unclear. Lipid mediators, known to be immediately generated in response to tissue injury, might be strong candidates for priming this particle-triggered change of the inflammatory balance.We hypothesize that inhalation of UfCP may disturb the balance of pro- and anti-inflammatory lipid mediators in: i) a model for acute allergic pulmonary inflammation, exposing mice for 24 h before allergen challenge to UfCP inhalation (51.7 nm, 507 ?g/m3), and ii) an in-vitro model with primary rat alveolar macrophages (AM) incubated with UfCP (10 ?g/1 x 106 cells/ml) for 1 h. Lungs and AM were analysed for pro- and anti-inflammatory lipid mediators, namely leukotriene B4 (LTB4), prostaglandin E2 (PGE2), 15(S)-hydroxy-eicosatetraenoic acid (15(S)-HETE), lipoxin A4 (LXA4) and oxidative stress marker 8-isoprostane by enzyme immunoassays and immunohistochemistry.In non-sensitized mice UfCP exposure induced a light non-significant increase of all lipid mediators. Similarly but significantly in rat AM all lipid mediators were induced already within 1 h of UfCP stimulation. Also sensitized and challenge mice exposed to filtered air showed a partially significant increase in all lipid mediators. In sensitized and challenged mice UfCP exposure induced highest significant levels of all lipid mediators in the lungs together with the peak of allergic airway inflammation on day 7 after UfCP inhalation. The levels of LTB4, 8-isoprostane and PGE2 were significantly increased also one day after UfCP exposure. Immunohistochemistry localized highest concentrations of PGE2 especially in AM one day after UfCP exposure.Our results suggest that UfCP exposure affects the balance between pro- and anti-inflammatory lipid mediators. In allergic mice, where the endogenous balance of pro- and anti-inflammatory mediators is already altered, UfCP exposure aggravates the inflammation and the increase in anti-inflammatory, pro-resolving lipid mediators is insufficient to counterbalance the extensive inflammatory response. This may be a contributing mechanism that explains the increased susceptibility of asthmatic patients towards particle exposure

Responses of human neutrophils to sulfite.

Exposure to sulfur dioxide or sulfite aerosols induce inflammatory reactions in the respiratory tract characterized by an influx of neutrophils into the airways. To determine direct intracellular effects of sulfite on human neutrophils, these cells were evaluated ultrastructurally by electron microscopy and analyzed for their extracellular and intracellular respiratory burst activity after incubation with sulfite (0.01-10 mM) in vitro. The respiratory burst was quantitated by measuring both the extracellular release of superoxide anions (O2-) by superoxide dismutase-inhibitable lucigenin-dependent chemiluminescence (CL) and the intracellular generation of hydrogen peroxide (H2O2) by flow cytometry using the reagent dichlorofluorescein diacetate. The addition of sulfite in concentrations of 0.01-1 mM resulted in sixfold increases in CL of resting neutrophils. Neutrophils stimulated with zymosan, phorbol myristate acetate (PMA), or N-formyl-methionine-leucine-phenylalanine further increased CL when sulfite was added. Higher sulfite concentrations (2-10 mM) decreased CL of resting, zymosan-stimulated, and PMA-stimulated cells. When sulfate was added, no changes in CL of resting and zymosan-stimulated neutrophils were seen, indicating that the effect is specific for sulfite. The intracellular generation of H2O2 in resting and PMA-stimulated neutrophils incubated with sulfite (0.1-2 mM) was increased twofold. These findings suggest that sulfite in low concentrations stimulates neutrophils by activating the respiratory burst to produce O2- and H2O2. Ultrastructural studies confirm the stimulating effect of sulfite on neutrophils with sulfite-treated cells exhibiting increased ruffled surface membranes, degranulation changes, and vesiculation similar to those seen in PMA-stimulated cells