Comparative toxicity of size-fractionated airborne particulate matter obtained from different cities in the United States

Hundreds of epidemiological studies have shown that exposure to ambient particulate matter (PM) is associated with dose-dependent increases in morbidity and mortality. While early reports focused on PM less than 10 microm (PM10), numerous studies have since shown that the effects can occur with PM stratified into ultrafine (UF), fine (FI), and coarse (CO) size modes despite the fact that these materials differ significantly in both evolution and chemistry. Furthermore the chemical makeup of these different size fractions can vary tremendously depending on location, meteorology, and source profile. For this reason, high-volume three-stage particle impactors with the capacity to collect UF, FI, and CO particles were deployed to four different locations in the United States (Seattle, WA; Salt Lake City, UT; Sterling Forest and South Bronx, NY), and weekly samples were collected for 1 mo in each place. The particles were extracted, assayed for a standardized battery of chemical components, and instilled into mouse lungs (female BALB/c) at doses of 25 and 100 microg. Eighteen hours later animals were euthanized and parameters of injury and inflammation were monitored in the bronchoalveolar lavage fluid and plasma. Of the four locations, the South Bronx coarse fraction was the most potent sample in both pulmonary and systemic biomarkers, with a strong increase in lung inflammatory cells as well as elevated levels of creatine kinase in the plasma. These effects did not correlate with lipopolysaccharide (LPS) or total zinc or sulfate content, but were associated with total iron. Receptor source modeling on the PM2.5 samples showed that the South Bronx sample was heavily influenced by emissions from coal fired power plants (31%) and mobile sources (22%). Further studies will assess how source profiles correlate with the observed effects for all locations and size fractions.     

Endotoxin induces late increase in the production of pulmonary proinflammatory cytokines in murine lupus-like pristane-primed modelp

Lupus-like syndrome is characterized by multiple organ injuries including lungs and kidneys. Endotoxin induces a transiently intent systemic inflammatory response and indirectly transient acute lung injury in normal condition. However, whether endotoxin may trigger the persistent development of lung injury in chronic, inflammatory lupus-like syndrome compared with normal condition remains unclear. We examined the pulmonary vascular permeability and production of proinflammatory cytokines, such as TNF-alpha, IL-6, IL-10 and IFN-gamma, which play prominent roles in the pathogenesis of lupus-like tissue injury, 6 h and 72 h after i.p. lipopolysaccharide (LPS; endotoxin) injection in pristane-primed chronic inflammation ICR mice characterized by a lupus-like syndrome. These results demonstrated that levels of serum IL-6, IL-10 and IFN-gamma and bronchoalveolar lavage (BAL) IL-6 and IFN-gamma were remarkably increased 6 h in LPS-exposed pristane-primed mice compared with pristane-primed controls, while pulmonary vascular permeability and levels of serum and BAL TNF-alpha were not. And levels of BAL TNF-alpha, IL-6 and IL-10 were significantly enhanced 72 h in LPS-exposed pristane-primed mice compared with pristane-primed controls. Also, LPS significantly induced the increased in vitro production of TNF-alpha, IL-6 and IL-10 by lung cells obtained from LPS-exposed pristane-primed mice compared with LPS-exposed normal mice. Our findings indicate that LPS may trigger persistent progression of lung injury through late overproduction of BAL TNF-alpha, IL-6, and IL-10 in lupus-like chronic inflammation syndrome compared with normal condition.     

Contribution of endotoxin in macrophage cytokine response to ambient particles in vitro

Ambient particles may cause pulmonary inflammation with ensuing morbidity. Particle-induced production of proinflammatory cytokines in vitro has been used as an indicator of particle toxicity. To identify particle components that were related to particle toxicity, Andersen dichotomous impactors were used to collect ambient fine (PM(2.5)) and coarse (PM(2.5-10)) particles in central Taiwan with extraction in endotoxin-free water. Mouse monocyte-macrophage cell line RAW 264.7 cells were exposed to particle extracts at 40 micro g/ml for 16 h, and tumor necrosis factor-alpha (TNF-alpha) was measured in the medium by enzyme-linked immunosorbent assay (ELISA). Cell viabilities were all greater than 82%. Coarse particles stimulated higher TNF-alphaproduction than fine particles, and this was associated with greater particulate endotoxin content. Polymyxin B inhibited 42% of TNF-alpha production elicited by coarse particles and 32% of TNF-alpha production elicited by fine particles. In fine particles, TNF-alpha production was negatively correlated with Zn content, while no element in coarse particles correlated with TNF-alpha production. Results suggest that endotoxin and other components may be important factors for TNF-alpha production by macrophages in vitro.     

PM2.5‐induced lung inflammation in mice: Differences of inflammatory response in macrophages and type II alveolar cells

Particulate matter 2.5 (<PM2.5 μm) leads to chronic obstructive pulmonary disease. In this study, biomarkers related to inflammation and oxidative stress in vitro and in vivo experiments were investigated to clarify the PM2.5‐induced lung inflammation mechanisms. In an in vitro study using RAW264.7 cells, PM2.5 caused phosphorylation of nuclear factor‐κB, p38 mitogen‐activated protein kinase and extracellular response kinases, an increase of proinflammatory gene and protein expressions (e.g. monocyte chemotactic protein‐1, tumor necrosis factor‐α). These biomarkers were substantially attenuated by polymyxin B (PMB). PM2.5 induced heme oxygenase‐1 (HO‐1) gene, which was attenuated by N‐ acetylcysteine (NAC). However, the suppressive effects of NAC on inflammatory biomarkers were very weak. In bone marrow‐derived macrophages (BMDMs) of wild‐type BALB/c mice, the effects of PMB and NAC on PM2.5‐induced inflammatory responses were similar to RAW264.7 cells. In BMDMs of MyD88^−/− mice, PM2.5‐induced proinflammatory mediators were substantially more attenuated. PM2.5 caused an increase of proinflammatory gene expressions (interleukin‐6, cyclooxygenase 2) and HO‐1 gene in MLE‐12 cells (mouse alveolar cell line). These biomarkers were substantially attenuated by NAC, but not by PMB. When BALB/c mice were exposed intratracheally to 0.2 mg PM2.5, PM2.5 caused severe lung inflammation, an increase of neutrophils along with proinflammatory mediators in bronchoalveolar lavage fluid. The inflammation was attenuated by NAC, particularly by NAC + PMB, but not by PMB alone. These results indicate that macrophages may act sensitively to lipopolysaccharide (LPS) present in PM2.5 and release proinflammatory mediators via the LPS/MyD88 pathway. However, type II alveolar cells may react sensitively to oxidative stress induced by PM2.5 and cause inflammatory response. Therefore, overall, PM2.5 may cause predominantly oxidative stress‐dependent inflammation rather than LPS/MyD88‐dependent inflammation in type II alveolar cell‐rich lungs. Copyright © 2017 John Wiley & Sons, Ltd.     

Pharmacodynamic interactions between recombinant mouse interleukin-10 and prednisolone using a mouse endotoxemia model

The pharmacodynamic interactions between recombinant mouse interleukin-10 (IL-10) and prednisolone were examined in lipopolysaccharide (LPS)-induced experimental endotoxemia in Balb/c mice. Treatment phases consists of single doses of IL-10 (10 microg/kg i.p.), prednisolone (25 (mg/kg i.p.), IL-10 (2.5 microg/kg i.p.) with prednisolone (6.25 mg/kg i.p.), or placebo (saline). Measurements included plasma steroid kinetics and IL-10 concentrations and responses to LPS including proinflammatory cytokines (TNF-alpha, IFN-gamma) and circulatory NO measured as plasma nitrate/nitrite concentrations. The intraperitoneal dosing of LPS produced large and transient elevations of plasma TNF-alpha, IFN-gamma, and NO concentrations. Noncompartmental and model fitting using extended indirect response models based on drug inhibition of multiphase stimulation of biomarkers by LPS were used to describe the in vivo pharmacodynamics and drug interactions. Dosing with prednisolone, IL-10, or their combinations produced strong inhibition of cytokine and NO production. The IC50 values of prednisolone ranged from 54 to 171 ng/mL, and IC50 values for IL-10 ranged from 0.06 to 0.69 ng/mL. The production of NO was described as a cascading consequence of the TNF-alpha and IFN-gamma plasma concentrations. The joint dosing of IL-10 with prednisolone produces moderately synergistic immunosuppressive effects in this system. Both drugs were sufficiently protective in suppressing the inflammatory mediators when administered prior to the LPS trigger, while such effects were modest when administered after the inflammatory stimulus was provoked. The integrated and complex pharmacokinetic/pharmacodynamic models well capture the in vivo processes, drug potencies, and interactions of IL-10 and prednisolone.     

Role of inducible nitric oxide synthase-derived nitric oxide in lipopolysaccharide plus interferon-gamma-induced pulmonary inflammation

Exposure of mice to lipopolysaccharide (LPS) plus interferon-gamma (IFN-gamma) increases nitric oxide (NO) production, which is proposed to play a role in the resulting pulmonary damage and inflammation. To determine the role of inducible nitric oxide synthase (iNOS)-induced NO in this lung reaction, the responses of inducible nitric oxide synthase knockout (iNOS KO) versus C57BL/6J wild-type (WT) mice to aspirated LPS + IFN-gamma were compared. Male mice (8-10 weeks) were exposed to LPS (1.2 mg/kg) + IFN-gamma (5000 U/mouse) or saline. At 24 or 72 h postexposure, lungs were lavaged with saline and the acellular fluid from the first bronchoalveolar lavage (BAL) was analyzed for total antioxidant capacity (TAC), lactate dehydrogenase (LDH) activity, albumin, tumor necrosis factor-alpha (TNF-alpha), and macrophage inflammatory protein-2 (MIP-2). The cellular fraction of the total BAL was used to determine alveolar macrophage (AM) and polymorphonuclear leukocyte (PMN) counts, and AM zymosan-stimulated chemiluminescence (AM-CL). Pulmonary responses 24 h postexposure to LPS + IFN-gamma were characterized by significantly decreased TAC, increased BAL AMs and PMNs, LDH, albumin, TNF-alpha, and MIP-2, and enhanced AM-CL to the same extent in both WT and iNOS KO mice. Responses 72 h postexposure were similar; however, significant differences were found between WT and iNOS KO mice. iNOS KO mice demonstrated a greater decline in total antioxidant capacity, greater BAL PMNs, LDH, albumin, TNF-alpha, and MIP-2, and an enhanced AM-CL compared to the WT. These data suggest that the role of iNOS-derived NO in the pulmonary response to LPS + IFN-gamma is anti-inflammatory, and this becomes evident over time.     

Persistent elevation of blood pressure by ambient coarse particulate matter after recovery from pulmonary inflammation in mice

Exposure to ambient particulate matter (PM) is associated with hypertension and cardiovascular diseases. Recently, we reported that exposure to fine and coarse PM caused pulmonary inflammation and pulmonary small arterial remodeling in mice, and osteopontin (OPN) level was elevated following PM exposure. However, in the present study, cotreatment with 5‐methoxytryptophan for 4 weeks partially reduced coarse PM‐induced pulmonary inflammation without reducing pulmonary OPN secretion or recovery from pulmonary arterial remodeling in mice. Persistent vascular dysfunction may lead to vascular remodeling. Therefore, we further compared the relationship between coarse PM‐induced inflammation and vascular dysfunction by exposing mice to PM before and after cessation of PM exposure. Oropharyngeal aspiration of PM for 8 weeks induced pulmonary inflammation and pulmonary small artery remodeling in mice, as well as increased serum C‐reactive protein and OPN concentrations and systolic blood pressure (SBP). After the cessation of PM exposure for another 8 weeks, lung inflammation had recovered and vascular remodeling had partially recovered. Elevation of OPN, metalloproteinases (MMPs), and cytokines in bronchioalveolar lavage were significantly reduced. However, PM‐induced systemic responses did not recover after the cessation of PM exposure. Notably, not only serum OPN and SBP remained significantly elevated; also, serum endothelin‐1, MMP‐9, and keratinocyte‐derived chemokine concentrations were significantly increased after cessation of PM exposure for another 8 weeks. These data suggested that systemic inflammation and systemic vascular dysfunction might be important in PM‐induced elevation of SBP. Furthermore, SBP elevation was persistent after cessation of PM exposure for 8 weeks.     

Effects of organic chemicals derived from ambient particulate matter on lung inflammation related to lipopolysaccharide

The effects of components of ambient particulate matter (PM) on individuals with predisposing respiratory disorders are not well defined. We have previously demonstrated that airway exposure to diesel exhaust particles (DEP) or organic chemicals (OC) extracted from DEP (DEP–OC) enhances lung inflammation related to bacterial endotoxin (lipopolysaccharide, LPS). The present study aimed to examine the effects of airway exposure to OC extracted from urban PM (PM–OC) on lung inflammation related to LPS. ICR mice were divided into four experimental groups that intratracheally received vehicle, LPS (2.5 mg/kg), PM–OC (4 mg/kg), or PM–OC + LPS. Lung inflammation, lung water content, and lung expression of cytokines were evaluated 24 h after intratracheal administration. LPS challenge elicited lung inflammation evidenced by cellular profiles of bronchoalveolar lavage fluid and lung histology, which was further aggravated by the combined challenge with PM–OC. The combination with PM–OC and LPS did not significantly exaggerate LPS-elicited pulmonary edema. LPS instillation induced elevated lung expression of interleukin-1β, macrophage inflammatory protein-1α, macrophage chemoattractant protein-1, and keratinocyte chemoattractant, whereas the combined challenge with PM–OC did not influence these levels. All the results were consistent with our previous reports on DEP–OC. These results suggest that the extracted organic chemicals from PM exacerbate infectious lung inflammation. The mechanisms underlying the enhancing effects are not mediated via the enhanced local expression of proinflammatory cytokines.     

Effects of inhaled nanoparticles on acute lung injury induced by lipopolysaccharide in mice

We have previously shown that intratracheal instillation of carbon nanoparticles exacerbates lung inflammation related to bacterial endotoxin (lipopolysaccharide, LPS) and subsequent systemic inflammation with coagulatory disturbance in mice [Inoue, K., Takano, H., Yanagisawa, R., Hirano, S., Sakurai, M., Shimada, A., Yoshikawa, T., 2006b. Effects of airway exposure to nanoparticles on lung inflammation induced by bacterial endotoxin in mice. Environ. Health Perspect. 114, 1325-1330]. The present study was performed to determine whether inhalation of diesel engine-derived nanoparticles also exacerbates the model. ICR mice were exposed for 5h to clean air or diesel engine-derived nanoparticles at a concentration of 15, 36, or 169 microg/m(3) after intratracheal challenge with 125 microg/kg of LPS or vehicle, and were sacrificed for evaluation 24h after the intratracheal challenge. Nanoparticles alone did not induce lung inflammation. Nanoparticle inhalation increased LPS-elicited inflammatory cell recruitment into the bronchoalveolar lavage fluid and lung parenchyma as compared with clean air inhalation in a concentration-dependent manner. Lung homogenates derived from the nanoparticle+LPS groups tended to have increased tumor necrosis factor-alpha level and chemotaxis activity for polymorphonuclear leukocytes as compared to those from the LPS group or the corresponding nanoparticle groups. Nanoparticle inhalation did not significantly increase lung expression of proinflammatory cytokines or facilitate systemic inflammation and coagulatory disturbance. Isolated alveolar macrophages (AMs) from nanoparticle-exposed mice showed greater production of interleukin-1beta and keratinocyte chemoattractant stimulated with ex vivo LPS challenge than those from clean air-exposed mice, although the differences did not reach statistical significance. These results suggest that acute exposure to diesel nanoparticles exacerbates lung inflammation induced by LPS.     

Acute cardiopulmonary alterations induced by fine particulate matter of S?o Paulo, Brazil.

The mechanisms involved in the association between air pollution and increased cardiovascular morbidity are not fully understood. The objective of this study was to test the hypothesis that fine particulate matter (PM(2.5)) induces systemic inflammation and vasoconstriction of small arteries in the lung and heart of rats. Thirty-eight healthy Wistar rats were anesthetized, intubated, and submitted to the instillation of 1 ml of distilled water diluted in the following solution: blank filter, 100 microg and 500 microg of PM(2.5). PM(2.5) was collected in glass fiber filters with a high-volume sampler. The animals were sacrificed 24 h after instillation when blood, heart, and lung samples were collected for morphological and wet-to-dry weight ratio analysis. PM(2.5) consisted of the following elements: sulphur, arsenic, bromine, chlorine, cobalt, iron, lanthanum, manganese, antimony, scandium, and thorium. Total reticulocytes significantly increased at both PM(2.5) doses (p < 0.05) while hematocrit levels increased in the 500 microg group (p < 0.05). Quantification of segmented neutrophils and fibrinogen levels showed a significant decrease, while lymphocytes counting increased with 100 microg of PM(2.5) (p < 0.05). A significant dose-dependent decrease of intra-acinar pulmonary arteriole lumen/wall ratio (L/W) was observed in PM groups (p < 0.001). Peribronchiolar arterioles L/W showed a significant decrease in the 500 microg group (p < 0.001). A significant increase in heart wet-to-dry weight ratio was observed in the 500 microg group (p < 0.001). In conclusion, fine environment particles in the city of S?o Paulo promote pulmonary and cardiac histological alterations. Pulmonary vasculature was markedly affected by particle instillation, resulting in significant vasoconstriction in healthy rats.     

Protective and anti-inflammatory effect of a traditional Chinese medicine, Xia-Bai-San, by modulating lung local cytokine in a murine model of acute lung injury

We investigated the effects of Xia-Bai-San (XBS) on acute lung inflammation induced by LPS in vivo. Mice were challenged with intratracheal lipopolysaccharide (100 microg) 30 min before administering XBS (1 mg/kg oral administration). Bronchoalveolar lavage fluid (BALF) was obtained after 4 and 24 h to measure proinflammatory cytokine (TNF-alpha, IL-1beta, IL-6), anti-inflammatory cytokines (IL-10), chemokines (KC, MCP-1 and MIP-2), total cell counts, nitric oxide production, and proteins. The results indicated that XBS down-regulated the LPS-induced expression of TNF-alpha, IL-1beta, IL-6, KC, MIP-2, and MCP-1. Furthermore, it also enhanced the production of IL-10, which had increased 24 h after LPS challenge. In addition, total leukocyte counts, nitric oxide production, iNOS expression, and BALF's proteins had significantly decreased 24 h after LPS challenge. XBS was also believes to have reduced the acute inflammation by attenuating the activation of NF-kappaB. In conclusion, XBS seem to suppress lipopolysaccharide-induced lung inflammation by stimulating the production of anti-inflammatory cytokines in lung. These results suggest that XBS could be a useful adjunct in the treatment of acute respiratory distress syndrome.     

Protective effects of pravastatin in murine lipopolysaccharide-induced acute lung injury

1. The present study was designed to determine whether pravastatin, a 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitor, could attenuate acute lung injury (ALI) induced by lipopolysaccharide (LPS) in BALB/c mice. 2. Acute lung injury was induced successfully by intratracheal administraiton of LPS (3 microg/g) in BALB/c mice. Pravastatin (3, 10 and 30 mg/kg, i.p.) was administered to mice 24 h prior to and then again concomitant with LPS exposure. 3. Challenge with LPS alone produced a significant increase in lung index and the wet/dry weight ratio compared with control animals. Pulmonary microvascular leakage, as indicated by albumin content in the bronchoalveolar lavage fluid (BALF) and extravasation of Evans blue dye albumin into lung tissue, was apparently increased in LPS-exposed mice. Lipopolysaccharide exposure also produced a significant lung inflammatory response, reflected by myeloperoxidase activity and inflammatory cell counts in BALF. Furthermore, histological examination showed that mice exposed to LPS also exhibited prominent inflammatory cell infiltration and occasional alveolar haemorrhage. 4. Pravastatin (3, 10 or 30 mg/kg, i.p.) produced a significant reduction in multiple indices of LPS-induced pulmonary vascular leak and inflammatory cell infiltration into lung tissue. Elevated tumour necrosis factor (TNF)-alpha levels in lung tissue homogenates of ALI mice were significantly decreased after administration of 10 or 30 mg/kg pravastatin. 5. These findings confirm significant protection by pravastatin against LPS-induced lung vascular leak and inflammation and implicate a potential role for statins in the management of ALI. The inhibitory effect of pravastatin was associated with its effect in decreasing TNF-alpha.     

P2 receptor blockade attenuates fever and cytokine responses induced by lipopolysaccharide in rats

Adenosine 5'-triphosphate (ATP) has been shown to induce release of cytokines implicated in fever, including interleukin(IL)-1beta, IL-6, and tumour necrosis factor-alpha (TNF-alpha). The role of ATP-mediated purinergic signalling in fever and cytokine release during systemic inflammation was investigated by studying the effects of P2 receptor antagonists suramin, pyridoxal-5'-phosphate-6-azophenyl-2',4'-disulphonic acid (PPADS), and Brilliant Blue G (BBG) on changes in body temperature and the increases in plasma levels of IL-1beta, IL-6, and TNFalpha induced by bacterial lipopolysaccharide (LPS) in rats. LPS (Escherichia coli; 50 microg kg(-1))-induced febrile response was attenuated by suramin (25 mg kg(-1) and 100 mg kg(-1)), PPADS (25 mg kg(-1)), and a more selective P2X(7) receptor antagonist BBG (100 mg kg(-1)) injected intraperitoneally before the induction of fever. The increase in plasma concentrations of IL-1beta and IL-6, measured 1 h after LPS treatment, was reduced by PPADS (25 mg kg(-1)) and BBG (100 mg kg(-1)). LPS-induced increase in plasma TNF-alpha concentration was also markedly attenuated by BBG (100 mg kg(-1)), but not by PPADS (25 mg kg(-1)). These data indicate that purinergic signalling plays an important role in the mechanisms responsible for the LPS-induced febrile response and increases in the levels of circulating cytokines. We suggest that ATP acting via P2X(7) receptors induces release of pyrogenic cytokines to mediate fever during systemic inflammation.     

Responses of well-differentiated nasal epithelial cells exposed to particles: role of the epithelium in airway inflammation

Numerous epidemiological studies support the contention that ambient air pollution particles can adversely affect human health. To explain the acute inflammatory process in airways exposed to particles, a number of in vitro studies have been performed on cells grown submerged on plastic and poorly differentiated, and on cell lines, the physiology of which is somewhat different from that of well-differentiated cells. In order to obtain results using a model system in which epithelial cells are similar to those of the human airway in vivo, apical membranes of well-differentiated human nasal epithelial (HNE) cells cultured in an air-liquid interface (ALI) were exposed for 24 h to diesel exhaust particles (DEP) and Paris urban air particles (PM(2.5)). DEP and PM(2.5) (10-80 microg/cm(2)) stimulated both IL-8 and amphiregulin (ligand of EGFR) secretion exclusively towards the basal compartment. In contrast, there was no IL-1beta secretion and only weak non-reproducible secretion of TNF-alpha. IL-6 and GM-CSF were consistently stimulated towards the apical compartment and only when cells were exposed to PM(2.5). ICAM-1 protein expression on cell surfaces remained low after particle exposure, although it increased after TNF-alpha treatment. Internalization of particles, which is believed to initiate oxidative stress and proinflammatory cytokine expression, was restricted to small nanoparticles (< or =40 nm). Production of reactive oxygen species (ROS) was detected, and DEP were more efficient than PM(2.5). Collectively, our results suggest that airway epithelial cells exposed to particles augment the local inflammatory response in the lung but cannot alone initiate a systemic inflammatory response.     

Pulmonary exposure to diesel exhaust particle components enhances circulatory chemokines during lung inflammation

This study examines the effects of DEP components on circulatory CC and CXC chemokines, potent activators and chemoattractants for macrophage and leukocyte subpopulations, in a murine model of lung inflammation. ICR mice were divided into six experimental groups which received intratracheal inoculation of vehicle, LPS alone (2.5 mg/kg), organic chemicals in DEP (DEP-OC: 4 mg/kg) extracted with dichloromethane, residual carbonaceous nuclei after the extraction (washed DEP: 4 mg/kg), DEP-OC + LPS, or washed DEP + LPS. Intratracheal instillation of each DEP component alone did not significantly change the circulatory level of macrophage inflammatory protein (MIP)-1alpha, MIP-2, and macrophage chemoattractant protein-1 (MCP-1) 24 h after the exposure as compared with vehicle instilled alone. In the LPS group, MCP-1, but not MIP-1alpha or MIP-2, was significantly greater than in the vehicle group. The combined administration of LPS and washed DEP caused a further three to five-fold increase in MIP-1alpha, MIP-2, and MCP-1 proteins in the serum as compared with LPS administered alone. No significant difference between the LPS + DEP-OC group and the LPS group was observed. These results indicate that pulmonary exposure to washed DEP enhances circulatory level of chemokines during lung inflammation. The enhancement may be important in the aggravations of systemic inflammatory responses and ischemic cardiovascular conditions associated with air pollution.     

An Anacardiaceae preparation reduces the expression of inflammation-related genes in murine macrophages

This study investigated the effects of an aqueous extract of the stem bark of Mangifera indica L. (Anacardiaceae; Vimang), which contains a defined mixture of components including polyphenols (principally mangiferin, MA), triterpenes, phytosteroids, fatty acids and microelements, on expression of inflammation mediators in inflammatory murine macrophages after stimulation in vitro with lipopolysaccharide (LPS) and interferon-gamma (IFN-gamma). In vitro treatment with Vimang at 4 microg/ml reduced levels of NOS-2 mRNA and NOS-2, while treatment at 40 microg/ml also reduced levels of COX-2 mRNA, COX-2, and prostaglandin E2 (PGE2). Results suggested that MA is involved in these effects. In vitro treatment with Vimang at 40 microg/ml also inhibited mRNA levels of the proinflammatory cytokines interleukin 1beta (IL-1beta), tumor necrosis factor alpha (TNF-alpha) and colony-stimulating factor (GM-CSF), but did not affect mRNA levels of IL-6 or tumor growth factor-beta (TGF-beta). Extracellular release of TNF-alpha by inflammatory macrophages was inhibited by in vitro treatment with Vimang at the same concentrations that showed inhibition of TNF-alpha mRNA levels. The inhibition of TNF-alpha production appears to be at least partially attributable to MA. Vimang at 4 microg/ml decreased mRNA levels of nuclear factor-kappaB (NF-kappaB) but did not affect expression of the NF-kappaB inhibitor (IkappaB). These data indicate that the potent anti-inflammatory effects of Vimang are due to selective modulation of the expression of inflammation-related genes, leading to attenuation of macrophage activation.     

Inhalation of activated protein C inhibits endotoxin-induced pulmonary inflammation in mice independent of neutrophil recruitment

BACKGROUND AND PURPOSE: Intravenous administration of recombinant human activated protein C (rhAPC) is known to reduce lipopolysaccharide (LPS)-induced pulmonary inflammation by attenuating neutrophil chemotaxis towards the alveolar compartment. Ideally, one would administer rhAPC in pulmonary inflammation at the site of infection to minimize the risk of systemic bleeding complications. In this study, we therefore assessed the effect of inhaled rhAPC in a murine model of acute lung injury. EXPERIMENTAL APPROACH: Mice were exposed to LPS (0.5 mg kg(-1): intranasally) to induce acute lung injury. 30 minutes before and 3 hours after LPS exposure mice were subjected to vehicle or rhAPC inhalation (25 or 100 microg per mouse in each nebulization). In order to establish whether rhAPC inhalation affects neutrophil recruitment, neutrophil migration was determined in vitro using a trans-well migration assay. KEY RESULTS: rhAPC inhalation dose-dependently decreased LPS-induced coagulation and inflammation markers in bronchoalveolar lavage fluid (BALF), reduced protein leakage into the alveolar space and improved lung function. In contrast, rhAPC did not prevent LPS-induced neutrophil recruitment into the alveolar space.Neutrophil migration in vitro towards FCS or interleukin (IL)-8 was significantly inhibited by pretreatment with rhAPC (0.01-10 microg ml(-1)], whereas rhAPC (10 microg ml(-1)) added to the chemoattractant (modelling for topical rhAPC administration) did not affect neutrophil migration towards FCS or IL-8. CONCLUSIONS AND IMPLICATIONS: rhAPC inhalation significantly diminished LPS-induced pulmonary inflammation. The benefit of inhaled rhAPC appeared not to involve attenuation of neutrophil recruitment, in contrast to its effects after intravenous administration.     

Immunomodulatory activity of betulinic acid by producing pro-inflammatory cytokines and activation of macrophages

Betulinic acid (BA), a pentacyclic triterpene isolated from Lycopus lucidus, has been reported to be a selective inducer of apoptosis in various human cancer and shown anti-inflammatory and immunomodulatory properties. We postulated that BA modulates the immunomodulatory properties at least two groups of protein mediators of inflammation, interleukin-1beta (IL-1beta) and the tumor necrosis factor-alpha (TNF-alpha) on the basis of the critical role of the monocytes and tissue macrophages in inflammatory and immune responses. TNF-alpha and IL-1beta were produced by BA in a dose dependent manner at concentration of 0.625 and 10 microg/mL. The production of NO associated with iNOS was inhibited when treated with LPS at the concentration of 2.5 to 20 microg/mL of BA whereas COX-2 expression was decreased at 2.5 to 20 microg/mL. These modulations of inflammatory mediators were examined in LPS-stimulated RAW 264.7 cells and peritoneal macrophages. The morphology of macrophage was also examined and enhanced surface CD 40 molecule was expressed when treated BA at 0.625 to approximately 5 microg/mL with or without LPS. Furthermore, BA (20 microg/mL) enhanced apoptosis by producing DNA ladder in the RAW 264.7 cells. Our results indicated that BA induced activation of macrophage and pro-inflammatory cytokines. This may provide a molecular basis for the ability of BA to mediate macrophage, suppress inflammation, and modulate the immune response.     

Urinary trypsin inhibitor protects against systemic inflammation induced by lipopolysaccharide

Urinary trypsin inhibitor (UTI), a serine protease inhibitor, has been widely used as a drug for patients with acute inflammatory disorders such as disseminated intravascular coagulation, shock, and pancreatitis in Japan. Recent studies have demonstrated that serine protease inhibitors may play an anti-inflammatory role beyond merely an inhibitory action on neutrophil elastase at the site of inflammation at least in vitro. To clarify the direct contributions of UTI to inflammatory condition in vivo, we analyzed its roles in experimental systemic inflammatory response induced by intraperitoneal administration of lipopolysaccharide (LPS) using UTI deficient (-/-) mice and corresponding wild-type (WT) mice. After LPS (1 mg/kg) challenge, UTI (-/-) mice revealed a significant elevation of plasma fibrinogen and fibrinogen/fibrin degradation products and a decrease in white blood cell counts compared with WT mice. LPS treatment induced more severe neutrophilic inflammation in the lung and the kidney obtained from UTI (-/-) mice than in those from WT mice, which was confirmed by histological examination. The protein levels of proinflammatory mediators, such as macrophage chemoattractant protein (MCP)-1 in the lungs, MCP-1 and keratinocyte chemoattractant (KC) in the kidneys, and interleukin-1beta, macrophage inflammatory protein-2, MCP-1, and KC in the liver, were significantly greater in UTI (-/-) mice than in WT mice after LPS challenge. Our results suggest that UTI protects against systemic inflammatory response and subsequent organ injury induced by bacterial endotoxin, at least partly through the inhibition of the enhanced expression of proinflammatory cytokines and chemokines.     

PM10‐biogenic fraction drives the seasonal variation of proinflammatory response in A549 cells

PM10 was collected in a Milan urban site, representative of the city air quality, during winter and summer 2006. Mean daily PM10 concentration was 48 μg m^?3 during summer and 148 μg m^?3 during winter. Particles collected on Teflon filters were chemically characterized and the endotoxin content determined by the LAL test. PM10‐induced cell toxicity, assessed with MTT and LDH methods, and proinflammatory potential, monitored by IL‐6 and IL‐8 cytokines release, were investigated on the human alveolar epithelial cell line A549 exposed to increasing doses of PM. Besides untreated cells, exposure to inert carbon particles (2–12 μm) was also used as additional control. Both cell toxicity and proinflammatory potency resulted to be higher for summer PM10 with respect of winter PM10, with IL‐6 showing the highest dose‐dependent release. The relevance of biogenic components adsorbed onto PM10 in eliciting the proinflammatory mediators release was investigated by inhibition experiments. Polymixin B (Poly) was used to inhibit particle‐bind LPS while Toll‐like receptor‐2 antibody (a‐TLR2) to specifically block the activation of this receptor. While cell viability was not modulated in cells coexposed to PM10 and Poly or a‐TLR2 or both, inflammatory response did it, with IL‐6 release being the most inhibited. In conclusion, Milan PM10‐induced seasonal‐dependent biological effects, with summer particles showing higher cytotoxic and proinflammatory potential. Cytotoxicity seemed to be unaffected by the PM biogenic components, while inflammation was significantly reduced after the inhibition of some biogenic activated pathways. Besides, the PM‐associated biogenic activity does not entirely justify the PM‐induced inflammatory effects. © 2010 Wiley Periodicals, Inc. Environ Toxicol 2012.