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Dynamics of pulmonary inflammation caused by isometric carbon nanoparticles or fibrous carbon nanotubes
S46
Abstracts / Toxicology Letters 205S (2011) S36–S59
OS5-8 Dynamics of pulmonary inflammation caused by isometric carbon nanoparticles or fibrous carbon nanotubes S. Hirn 1,∗ , F. Tian 1 , S. Takenaka 1 , K. Kostarellos 2 , W. Kreyling 1 , T. Stöger 1 1 Comprehensive Pneumology Center (CPC) Institute of Lung Biology + Disease (ilbd), Helmholtz Center Munich, Munich, Germany, 2 Centre for Drug Delivery Research, School of Pharmacy, University of London, London, UK
Inhalation of some fiber shaped carbon nanotubes (CNT) is known to cause long term lung damage while isometric carbon nanoparticles (CNP) induce only acute inflammation. Since both materials consist of elementary carbon, particle shape is seen as key driver for the persistent, not resolving inflammation. We studied bronchoalveolar lavage (BAL) cell differentiation and BAL cytokine levels of mice 1, 3, 7, or 90 days after intratracheal instillation of either 50 g double walled CNT (DWNT; diameter: 4 nm, length: 1–10 m, specific surface area (SSA): 660 m2 /g) or CNP (primary particle diameter: 10 nm, SSA: 800 m2 /g) to distinguish characteristic responses to these materials. Both exposures caused comparable acute lung inflammation on day 1, while upon CNP instillation the influx declined to 51 ± 7 × 103 neutrophils by day 7 and to baseline till day 90. DWNT exposure caused a second boost of 150 ± 24 × 103 neutrophils on day 7 with remaining 49 ± 4 × 103 cells on day 90. This second peak was associated with high levels of (i) the neutrophile attractants CXCL1 and CXCL5, but also (ii) the macrophage attractant CCL2, although no macrophage accumulation was detected. The latter might be explained by cell necrosis indicated by high BAL LDH levels peaking simultaneously. Our data suggest two different mechanisms for the inflammatory response to the two carbon nanomaterials. In either case, the carbon surface activity, triggered by similar SSA caused an acute but transient inflammation. The fiber shaped CNT caused a second inflammatory response without resolution. The underlying mechanism may therefore be related to long term responses against inhaled fibrous nanomaterials. doi:10.1016/j.toxlet.2011.05.180
OS6 Metals
OS6-1 Inorganic arsenic increases IL-8 expression induced by lipopolysaccharide through activation of a reactive oxygen species/Src/p38-kinase signalling pathway L. Vernhet ∗ , E. Bourdonnay, C. Morzadec, O. Fardel IRSET, Ea-4427 Seraic, Unviersité de Rennes-1, Rennes, France Purpose: Chronic exposure to inorganic arsenic can increase the risk of deaths due to infectious diseases. Toxicological and clinical studies suggest that this metalloid may promote infection by increasing inflammation induced by lipopolysaccharide (LPS). In the present study, we determined molecular basis of arsenic trioxide (ATO) effects on inflammatory gene expression induced by LPS. Methods: Gene expression was quantified in human peripheral blood monocytes by quantitative polymerase chain reaction. ELISA, Western blotting, kinase and phosphatase assays, and flow cytometry were used to investigate signalling pathways controlling
interleukine-8 (IL-8) gene expression in the monocytic U937 cells. Results: Pre-treatment with 1 M ATO for 48 h increases expression of different inflammatory genes, including that of IL-8, in some, but not all, cultures of monocytes activated with LPS. ATO (0.5–2 M) also increases IL-8 expression at mRNA and protein levels, in LPS-stimulated U937 cells. This up-regulation of IL-8 expression occurs through enhancement of LPS-dependent activation of the mitogene-activated protein kinase p38 (p38-kinase). The increased activation of p38-kinase is likely mediated by an ATO-dependent production of reactive oxygen species (ROS) and subsequent activation of the tyrosine kinase Src. The antioxidant N-acetylcysteine almost totally prevents ROS production, ATO-dependent phosphorylation of both Src and p38-kinase, and the increase of IL-8 expression in LPS-stimulated cells. Finally, as observed with ATO, pre-treatment of U937 cells with hydrogen peroxide markedly increases LPS-dependent expression of IL-8 gene. In conclusion, our study suggests that ATO increases LPS-dependent expression of the inflammatory IL-8 gene by activating a ROS/Src/p38-kinase signalling pathway. doi:10.1016/j.toxlet.2011.05.182
OS6-2 Differences in heavy metal exposure to fetuses and breast-feeding infants M. Sakamoto 1,∗ , K. Murata 2 , K. Nakai 3 , H. Satoh 3 1
Epidemiology, National Institute for Minamata Disease, Minamata, Japan, 2 Environmental Health Science, Akita University School of Medicine, Akita, Japan, 3 Environmental Health Sciences, Tohoku University Graduate School of Medicine, Sendai, Japan
In this study, Hg and other heavy metal profiles of red blood cells (RBCs) were investigated in mothers and umbilical cords at parturition, and infants at 3 months of age. Sixteen pairs of blood samples were collected immediately after birth, maternal blood 1 day after parturition, and infants at 3 months of age. Total Hg (THg) in RBCs was determined by cold vapor atomic absorption spectrophotometry (CVAAS), and other metals were analyzed using ICP-MS. Means (ng/g) of maternal, cord blood, and infants RBCs were (8.2 ± 3.43, 13.0 ± 5.4, and 6.9 ± 2.4) for Hg (24.3 ± 10.8, 14.1 ± 4.3, and 16.1 ± 2.0) for Pb (7.0 ± 4.5, 4.3 ± 3.0 and 2.0 ± 0.7) for As (2.9 ± 0.9, 0.6 ± 0.1, and 0.6 ± 0.1) and for Cd (246 ± 27, 280 ± 40, and 212 ± 30) for Se, respectively. Correlations between maternal and cord RBCs were strong for Hg (0.88), Pb (0.74), As (0.88), Se (0.67), and weak for Cd (0.075). The means of the Hg and Se concentrations in cord RBCs were 1.6 times higher than those in maternal RBCs. The means of the Pb, As and Cd concentrations in cord RBCs were 58%, 62% and 19% of those in maternal RBCs, respectively. After a 3 month breast-feeding period, the Hg, Se and As concentrations in infants decreased to about 50% of those at birth, and Pb and As levels were almost the same. Among these metals, the placental transfer of MeHg seemed to be extremely high but that of Cd was limited. Further, if there is no special contamination to those metals during breast-feeding, these metals will not accumulate in infants at high concentrations. doi:10.1016/j.toxlet.2011.05.183
Abstracts / Toxicology Letters 205S (2011) S36–S59
OS5-8 Dynamics of pulmonary inflammation caused by isometric carbon nanoparticles or fibrous carbon nanotubes S. Hirn 1,∗ , F. Tian 1 , S. Takenaka 1 , K. Kostarellos 2 , W. Kreyling 1 , T. Stöger 1 1 Comprehensive Pneumology Center (CPC) Institute of Lung Biology + Disease (ilbd), Helmholtz Center Munich, Munich, Germany, 2 Centre for Drug Delivery Research, School of Pharmacy, University of London, London, UK
Inhalation of some fiber shaped carbon nanotubes (CNT) is known to cause long term lung damage while isometric carbon nanoparticles (CNP) induce only acute inflammation. Since both materials consist of elementary carbon, particle shape is seen as key driver for the persistent, not resolving inflammation. We studied bronchoalveolar lavage (BAL) cell differentiation and BAL cytokine levels of mice 1, 3, 7, or 90 days after intratracheal instillation of either 50 g double walled CNT (DWNT; diameter: 4 nm, length: 1–10 m, specific surface area (SSA): 660 m2 /g) or CNP (primary particle diameter: 10 nm, SSA: 800 m2 /g) to distinguish characteristic responses to these materials. Both exposures caused comparable acute lung inflammation on day 1, while upon CNP instillation the influx declined to 51 ± 7 × 103 neutrophils by day 7 and to baseline till day 90. DWNT exposure caused a second boost of 150 ± 24 × 103 neutrophils on day 7 with remaining 49 ± 4 × 103 cells on day 90. This second peak was associated with high levels of (i) the neutrophile attractants CXCL1 and CXCL5, but also (ii) the macrophage attractant CCL2, although no macrophage accumulation was detected. The latter might be explained by cell necrosis indicated by high BAL LDH levels peaking simultaneously. Our data suggest two different mechanisms for the inflammatory response to the two carbon nanomaterials. In either case, the carbon surface activity, triggered by similar SSA caused an acute but transient inflammation. The fiber shaped CNT caused a second inflammatory response without resolution. The underlying mechanism may therefore be related to long term responses against inhaled fibrous nanomaterials. doi:10.1016/j.toxlet.2011.05.180
OS6 Metals
OS6-1 Inorganic arsenic increases IL-8 expression induced by lipopolysaccharide through activation of a reactive oxygen species/Src/p38-kinase signalling pathway L. Vernhet ∗ , E. Bourdonnay, C. Morzadec, O. Fardel IRSET, Ea-4427 Seraic, Unviersité de Rennes-1, Rennes, France Purpose: Chronic exposure to inorganic arsenic can increase the risk of deaths due to infectious diseases. Toxicological and clinical studies suggest that this metalloid may promote infection by increasing inflammation induced by lipopolysaccharide (LPS). In the present study, we determined molecular basis of arsenic trioxide (ATO) effects on inflammatory gene expression induced by LPS. Methods: Gene expression was quantified in human peripheral blood monocytes by quantitative polymerase chain reaction. ELISA, Western blotting, kinase and phosphatase assays, and flow cytometry were used to investigate signalling pathways controlling
interleukine-8 (IL-8) gene expression in the monocytic U937 cells. Results: Pre-treatment with 1 M ATO for 48 h increases expression of different inflammatory genes, including that of IL-8, in some, but not all, cultures of monocytes activated with LPS. ATO (0.5–2 M) also increases IL-8 expression at mRNA and protein levels, in LPS-stimulated U937 cells. This up-regulation of IL-8 expression occurs through enhancement of LPS-dependent activation of the mitogene-activated protein kinase p38 (p38-kinase). The increased activation of p38-kinase is likely mediated by an ATO-dependent production of reactive oxygen species (ROS) and subsequent activation of the tyrosine kinase Src. The antioxidant N-acetylcysteine almost totally prevents ROS production, ATO-dependent phosphorylation of both Src and p38-kinase, and the increase of IL-8 expression in LPS-stimulated cells. Finally, as observed with ATO, pre-treatment of U937 cells with hydrogen peroxide markedly increases LPS-dependent expression of IL-8 gene. In conclusion, our study suggests that ATO increases LPS-dependent expression of the inflammatory IL-8 gene by activating a ROS/Src/p38-kinase signalling pathway. doi:10.1016/j.toxlet.2011.05.182
OS6-2 Differences in heavy metal exposure to fetuses and breast-feeding infants M. Sakamoto 1,∗ , K. Murata 2 , K. Nakai 3 , H. Satoh 3 1
Epidemiology, National Institute for Minamata Disease, Minamata, Japan, 2 Environmental Health Science, Akita University School of Medicine, Akita, Japan, 3 Environmental Health Sciences, Tohoku University Graduate School of Medicine, Sendai, Japan
In this study, Hg and other heavy metal profiles of red blood cells (RBCs) were investigated in mothers and umbilical cords at parturition, and infants at 3 months of age. Sixteen pairs of blood samples were collected immediately after birth, maternal blood 1 day after parturition, and infants at 3 months of age. Total Hg (THg) in RBCs was determined by cold vapor atomic absorption spectrophotometry (CVAAS), and other metals were analyzed using ICP-MS. Means (ng/g) of maternal, cord blood, and infants RBCs were (8.2 ± 3.43, 13.0 ± 5.4, and 6.9 ± 2.4) for Hg (24.3 ± 10.8, 14.1 ± 4.3, and 16.1 ± 2.0) for Pb (7.0 ± 4.5, 4.3 ± 3.0 and 2.0 ± 0.7) for As (2.9 ± 0.9, 0.6 ± 0.1, and 0.6 ± 0.1) and for Cd (246 ± 27, 280 ± 40, and 212 ± 30) for Se, respectively. Correlations between maternal and cord RBCs were strong for Hg (0.88), Pb (0.74), As (0.88), Se (0.67), and weak for Cd (0.075). The means of the Hg and Se concentrations in cord RBCs were 1.6 times higher than those in maternal RBCs. The means of the Pb, As and Cd concentrations in cord RBCs were 58%, 62% and 19% of those in maternal RBCs, respectively. After a 3 month breast-feeding period, the Hg, Se and As concentrations in infants decreased to about 50% of those at birth, and Pb and As levels were almost the same. Among these metals, the placental transfer of MeHg seemed to be extremely high but that of Cd was limited. Further, if there is no special contamination to those metals during breast-feeding, these metals will not accumulate in infants at high concentrations. doi:10.1016/j.toxlet.2011.05.183