Project description:Particulate Matter Triggers Carotid Body Dysfunction, Respiratory Dysynchrony and Cardiac Arrhythmias in Mice with Cardiac Failure; The mechanistic link between human exposure to airborne particulate matter (PM) pollution and the increased cardiovascular morbidity and mortality observed in people with congestive heart failure (CHF) is unknown. We now show that exposure of genetically-engineered mice with CHF (expressing a cardiac-specific CREB mutant transcription factor) to ambient PM (collected in Baltimore, mean aerodynamic diameter 1.9 um) unmasks severe autonomic morbidities manifested as significant reductions in heart rate variability, respiratory dysynchrony and increased frequency of serious ventricular arrhythmias, features not observed in PM-challenged wild type mice without CHF. PM exposure in CREB mice with CHF reflexly triggers autonomic dysfunction via heightened carotid body function as evidenced by pronounced afferent nerve responses to hypoxia and marked depression of breathing by hyperoxia challenge. Genomic analyses of lung and ventricular tissues revealed PM-induced molecular signatures of inflammation and oxidative stress. These findings in a murine model of cardiac failure provide the first direct assessment of autonomic function in response to PM challenge and are highly consistent with current epidemiologic findings on cardiovascular morbidity in susceptible PM-exposed human populations. We utilized a murine model of dilated cardiomyopathy to address potential mechanistic links between PM exposure and the development of life-threatening cardiac dysrhythmias. Experiment Overall Design: four group (n=3) of animals were treated by PBS or particulate matter (20mg/kg 1.9µm particulate matter) in Wild type or CD-1 dominate negative mice
Project description:To seek whether seasonal variation in environmental particulate matter composition affected the global gene response patterns in cultured human cells representing pulmonary and systemic vascular targets. We used microarrays to detail the global program of gene expression affected on different cells type by different seasonal collections of Ambient Particulate Matter.
Project description:To seek whether seasonal variation in environmental particulate matter composition affected the global gene response patterns in cultured human cells representing pulmonary and systemic vascular targets. We used microarrays to detail the global program of gene expression affected on different cells type by different seasonal collections of Ambient Particulate Matter. After treatment with 10 ug/mL either summer2006 or winter2007APM, endothelial or bronchail epithelial cells were isolated by RNA extraction and hybridization on Affymetrix microarrays. We sought to obtain the genes responses correlated with current concepts of systemic inflammation in cardiovascular effects of particulate air pollution.
Project description:Particulate Matter Triggers Carotid Body Dysfunction, Respiratory Dysynchrony and Cardiac Arrhythmias in Mice with Cardiac Failure The mechanistic link between human exposure to airborne particulate matter (PM) pollution and the increased cardiovascular morbidity and mortality observed in people with congestive heart failure (CHF) is unknown. We now show that exposure of genetically-engineered mice with CHF (expressing a cardiac-specific CREB mutant transcription factor) to ambient PM (collected in Baltimore, mean aerodynamic diameter 1.9 um) unmasks severe autonomic morbidities manifested as significant reductions in heart rate variability, respiratory dysynchrony and increased frequency of serious ventricular arrhythmias, features not observed in PM-challenged wild type mice without CHF. PM exposure in CREB mice with CHF reflexly triggers autonomic dysfunction via heightened carotid body function as evidenced by pronounced afferent nerve responses to hypoxia and marked depression of breathing by hyperoxia challenge. Genomic analyses of lung and ventricular tissues revealed PM-induced molecular signatures of inflammation and oxidative stress. These findings in a murine model of cardiac failure provide the first direct assessment of autonomic function in response to PM challenge and are highly consistent with current epidemiologic findings on cardiovascular morbidity in susceptible PM-exposed human populations. We utilized a murine model of dilated cardiomyopathy to address potential mechanistic links between PM exposure and the development of life-threatening cardiac dysrhythmias.
Project description:Exposure to ambient particulate matter (PM) significantly increases cardiovascular morbidity and mortality in the general population. We hypothesized that some components of PM can affect the gene expression patterns in the hearts of rats exposed for 3 months to filtered air (FA), coarse (CP; 2.5 < dp < 10 μm), fine (FP; dp ≤ 2.5 μm) or ultrafine (UFP; dp ≤ 0.18 μm) components of PM. The median diameters of CP, FP, and UFP were 3 μm, 0.7 μm and 0.07 μm, respectively. Exposures (n = 8 per group) were performed using a particle concentrator system in Riverside, California, an area with high ambient levels of photochemically derived gaseous and particulate pollutants. At the end of the exposure, hearts were subjected to gene expression profiling by using Illumina RatRef-12 bead chips and levels of malonaldehyde (MDA), a biomarker of oxidative stress, were measured. Applying fold ratio >1.5 (for both up- and downregulated genes), we found three genes in the CP and nine genes in the UFP groups with significantly changed expression, compared with FA. No significant changes in gene expression patterns were observed in the FP group. In the UFP group, thioredoxin-interacting protein (Txnip), a negative regulator of an antioxidant enzyme thioredoxin, and cytochrome P450 (Cyp2e1), an enzyme involved in the metabolism of foreign substances, demonstrated significant up-regulation (fold ratios 1.79 and 1.57, respectively, with false discovery rate, FDR < 0.05). In the CP group, there was also a trend towards increased Txnip expression (fold ratio 1.43, FDR > 0.05) and significant increase in the Cyp2e1 expression (fold ratio 1.79, FDR < 0.05). Changes in the Txnip and Cyp2e1 expression showed statistically significant positive correlation to each other (p < 0.0009) and were confirmed by real-time PCR. In addition, Txnip and Cyp2e1 expression demonstrated statistically significant moderate correlation with the levels of MDA in the heart. Up-regulation of both Cyp2e1 and Txnip are observed in hearts of patients with certain cardiac diseases. Therefore, chronic exposure to CP and UFP directly affects expression of disease-relevant genes in the myocardium.
Project description:Zinc is a common metal in most ambient particulate matter (PM), and has been proposed to be a causative component in PM-induced adverse cardiovascular health effects. Zinc is also an essential metal and has the potential to induce many physiological and nonphysiological changes. Most toxicological studies employ high levels of zinc. We hypothesized that subchronic inhalation of environmentally relevant levels of zinc would cause cardiac changes in healthy rats. To address this question, healthy male WKY rats (12 wks age) were exposed via nose only inhalation to filtered air or 10, 30 or 100 ug/m3 of aerosolized Zn in sulfate form, 5 h/d, 3 d/wk for 16 wks. Necropsies occurred 48 h after the last exposure to ensure effects were due to chronic exposure rather than the last exposure. No significant changes were observed in neutrophil or macrophage count, total lavageable cells, or enzyme activity levels (lactate dehydrogenase, n-acetyl ?-D-glucosaminidase, ?-glutamyl transferase) in bronchoalveolar lavage fluid, indicating minimal pulmonary effect. In the heart, cytosolic glutathione peroxidase activity decreased, while mitochondrial ferritin levels increased and succinate dehydrogenase activity decreased, suggesting a mitochondria-specific effect. Although no cardiac pathology was seen, cardiac gene array analysis indicated changes in genes involved in cell signaling, a pattern concordant with known zinc effects. These data indicate that inhalation of zinc at environmentally relevant levels may induce cardiac effects. While changes are small in healthy rats, these may be especially relevant in individuals with pre-existent cardiovascular disease. Keywords: dose response
Project description:Zinc (Zn) is a major elemental component of respirable ambient particulate matter (PM) detected often at alarming levels in urban air. Exposure to PM has been widely associated with increased cardiovascular morbidity and mortality, however, it is not known what components or sources of PM are causative. We recently demonstrated that long-term episodic inhalation of combustion PM, having similar amount of Zn found in urban PM, caused myocardial lesions in rats. We further demonstrated that a single pulmonary exposure to Zn at high concentration is associated with disturbances in cardiac mitochondrial function, ion channel regulation, calcium homeostasis, and cell signaling. Therefore, in this study we investigated the role of PM-associated Zn in cardiac injury using multiple exposure scenarios. Male Wistar-Kyoto (WKY) rats of 12-14 wks age were intratracheally exposed (once per wk x 8 or16 wks) to either (1) saline (control); (2) PM having no soluble Zn; (3) combustion PM suspension containing 14.5 ug/mg water-soluble Zn at high and (4) low dose levels, (5) the aqueous fraction of this suspension devoid of solid insoluble particulate fraction (14.5 ug/mg soluble Zn), or (6) Zn sulfate. Zn concentrations were identical in groups 3, 5 and 6. Pulmonary toxicity was apparent in all exposure groups when compared to saline as determined by recovery of cells in bronchoalveolar lavage fluid. Long-term exposure to PM with or without soluble Zn, or Zn sulfate caused distinct myocardial lesions characterized by subepicardial and randomly distributed myocardial inflammation, degeneration, and fibrosis. The lesion severity was higher in those groups receiving Zn PM. Because cardiac mitochondria are likely the primary target of inhaled metal or other absorbed PM components, we analyzed mitochondrial DNA damage using QPCR and found that all exposure groups except those exposed to PM without Zn caused variable degree of damage. Aconitase activity, sensitive to inhibition by oxidative stress was inhibited slightly but significantly in rats receiving zinc sulfate. Although modest, microarray (Affymetrix) analysis revealed expression changes in the heart reflective of effects on cell signaling, inflammation/oxidative stress, mitochondrial fatty acid metabolisms and cell cycle regulation in rats exposed to zinc sulfate. However, these changes were minimal following exposure to PM devoid of soluble metals. We demonstrate that episodic subchronic pulmonary exposure to zinc sulfate causes cardiac injury and mitochondrial DNA damage. Thus, water-soluble PM-associated zinc may be one of the PM components responsible for cardiovascular morbidity. Keywords: Pulmonary exposure, Cardiac gene expression
Project description:Murine Pulmonary Responses to Ambient Baltimore Particulate Matter: Genomic Analysis and Contribution to Airway Hyperresponsiveness; Asthma is a complex disease characterized by airway hyperresponsiveness (AHR) and chronic airway inflammation. Environmental factors such as ambient particulate matter (PM), a major air pollutant, has been demonstrated in epidemiological studies to contribute to asthma exacerbation and increased asthma prevalence. OBJECTIVE: We investigated the genomic and pathophysiological effects of Baltimore PM (median diameter 1.78 µm) in a murine model of asthma to identify potential biomarkers. METHODS: A/J mice with ovalbumin (OVA) âinduced AHR were exposed to PM (20 mg/kg, intratracheal), and both AHR and bronchoalveolar lavage (BAL) were assayed on days 1, 4, and 7 post exposure. Lung gene expression profiling (Affymetrix Mouse430_ 2.0) by PM (20 mg/kg, intratracheal) were assayed on OVA- and / or PM--challenged mice. RESULTS: Significant increases of airway responsiveness in OVA-treated mice were observed, indicating an asthmatic phenotype. Ambient PM exposure induced significant changes in AHR in both naive mice and OVA-induced asthmatic mice. In both naive and OVA challenged asthmatic mice, PM induced eosinophil and neutrophil infiltration into airways, elevated BAL protein content, and stimulated secretion of TH1 cytokines (IFN-g, IL-6, and TNF-a) and TH2 cytokines (IL-4, IL-5, and eotaxin) into BAL. Consistent with these results, PM induced expression of genes of innate immune response, chemotaxis and complementary system. CONCLUSION: These studies, consistent with epidemiological data, indicate that PM increases AHR and lung inflammation in naïve mice and exacerbates the asthma phenotype of increased AHR and gene expression pattern changes correlated with acute lung inflammation and airway damage. We used microarrays to detail the global programme of gene expression induced by rhPBEF treatment and VALI. Experiment Overall Design: animals were treated by PBS, Oval albumin, PM, or both OVA/PM