Dataset Information

A randomized cross-over study of inhalation of diesel exhaust, hematological indices, and endothelial markers in humans.

ABSTRACT:

Background

Exposure to traffic-related air pollution (TRAP) is considered a trigger for acute cardiovascular events. Diesel Exhaust (DE) is a major contributor to TRAP in the world. We evaluated the effect of DE inhalation on circulating blood cell populations, hematological indices, and systemic inflammatory cytokines in humans using a specialized facility.

Methods

In a randomized double-blind crossover study balanced to order, 17 metabolic syndrome (MetS) and 15 healthy subjects inhaled filtered air (FA) or DE exposure in two-hour sessions on different days with a minimum 2-week washout period. We collected blood pre-exposure, 7, and 22 hours after exposure initiation and measured the complete blood count and differential. We performed multiplex cytokine assay to measure the changes in the systemic inflammatory cytokines, and endothelial adhesion molecules (n=15). A paired analysis compared the effect of DE and FA exposures for the change from pre-exposure to the subsequent time points.

Results

A significant increase in the hematocrit was noted 7 hrs after DE [1.4% (95% CI: 0.9 to 1.9%)] compared to FA exposure [0.5% (95% CI: -0.09 to 1.0%); p=0.008. The hemoglobin levels increased non-significantly at 7 hrs post DE [0.3 gm/dL (95% CI: 0.2 to 0.5 gm/dL)] versus FA exposure [0.2 gm/dL (95% CI: 0 to 0.3 gm/dL)]; p=0.06. Furthermore, the platelet count increased 22 hrs after DE exposure in healthy, but not in MetS subjects [DE: 16.6 (95% CI: 10.2 to 23) thousand platelets/mL versus [FA: 3.4 (95% CI: -9.5 to 16.3) thousand platelets/mL)]; p=0.04. No DE effect was observed for WBC, neutrophils, lymphocytes or erythrocytes. Using the multiplex assay, small borderline significant increases in matrix metalloproteinase-9, interleukins (IL)-1 beta, 6 and 10 occurred 7 hrs post exposure initiation, whereas E-selectin, intercellular adhesion molecule-1, and vascular cell adhesion molecule -1, and myeloperoxidase 22 hrs post exposure.

Conclusions

Our results suggest that short-term DE exposure results in hemoconcentration and thrombocytosis, which are important determinants of acute cardiovascular events. Multiplex assay showed a non-significant increase in IL-1? and IL-6 immediately post exposure followed by myeloperoxidase and endothelial activation molecules. Further specific assays in a larger population will improve our understanding of the systemic inflammatory mechanisms following acute exposure to TRAP.

SUBMITTER: Krishnan RM

PROVIDER: S-EPMC3637197 | biostudies-literature | 2013 Mar

REPOSITORIES: biostudies-literature

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Publications

A randomized cross-over study of inhalation of diesel exhaust, hematological indices, and endothelial markers in humans.

Krishnan Ranjini M RM Sullivan Jeffrey H JH Carlsten Chris C Wilkerson Hui-Wen HW Beyer Richard P RP Bammler Theo T Farin Fred F Peretz Alon A Kaufman Joel D JD

Particle and fibre toxicology 20130326

<h4>Background</h4>Exposure to traffic-related air pollution (TRAP) is considered a trigger for acute cardiovascular events. Diesel Exhaust (DE) is a major contributor to TRAP in the world. We evaluated the effect of DE inhalation on circulating blood cell populations, hematological indices, and systemic inflammatory cytokines in humans using a specialized facility.<h4>Methods</h4>In a randomized double-blind crossover study balanced to order, 17 metabolic syndrome (MetS) and 15 healthy subjects ...[more]

PMID: 23531317

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Project description:Background: Epidemiologic associations between acutely increased cardiorespiratory morbidity and mortality and particulate air pollution are well-established, but the effects of acute pollution exposure on human gene expression changes are not well understood. Objectives: In order to identify potential mechanisms underlying epidemiologic associations between air pollution and morbidity, we explored changes in gene expression in humans following inhalation of fresh diesel exhaust (DE), a model for particulate air pollution. Methods: 14 ethnically homogeneous (white males), young, healthy subjects underwent sixty minute inhalation exposures on 2 separate days with clean air (CA) or freshly generated and diluted DE at a concentration of 300 Î¼g/m3 PM2.5. Prior to and 24 hours following each session, whole blood was sampled and fractionated for PBMC isolation, RNA extraction, and generation of cDNA, followed by hybridizationÂ withÂ Agilent Whole Human Genome (4X44K) arrays. Results: Oxidative stress and the ubiquitin proteasome pathway, as well as the coagulation system, were among hypothesized pathways identified by analysis of differentially expressed genes. Nine genes from these pathways were validated using real-time PCR comparing fold change in expression between DE exposed and clean (CA) days. Quantitative gene fold changes generated by real-time PCR were consistent with the directional fold changes from the microarray analysis. Conclusions: Changes in gene expression connected with key oxidative stress, protein degradation, and coagulation pathways are likely to underlie observed physiologic and clinical outcomes and suggest specific avenues and sensitive time points for further physiologic exploration. Diesel exhaust inhalation exposure-induced human gene expression changes were measured in peripheral blood mononuclear cells. 14 white males subjects were seated in a controlled environment facility for 2 separate 60 minute inhalation exposures which occurred at least 1 week apart to either clean air and freshly generate or diluted diesel exhaust (300ug/m3 PM2.5) .Blood collection occurred immediately prior to and 24 hours following exposures. Two microarrays per subject were completed using Agilent Whole Human Genome (4X44K) arrays. Genes that were of interest to our research group were verified using Real Time PCR analysis.

Project description:BackgroundRecent epidemiological studies indicate early-life exposure to pollution particulate is associated with adverse neurodevelopmental outcomes. The need is arising to evaluate the risks conferred by individual components and sources of air pollution to provide a framework for the regulation of the most relevant components for public health protection. Previous studies in rodent models have shown diesel particulate matter has neurotoxic potential and could be a health concern for neurodevelopment. The present study shows an evaluation of pathological and protracted behavioral alterations following neonatal exposure to aerosolized diesel exhaust particles (NIST SRM 1650b). The particular behavioral focus was on temporal control learning, a broad and fundamental cognitive domain in which reward delivery is contingent on a fixed interval schedule. For this purpose, C57BL/6?J mice were exposed to aerosolized NIST SRM 1650b, a well-characterized diesel particulate material, from postnatal days 4-7 and 10-13, for four hours per day. Pathological features, including glial fibrillary-acidic protein, myelin basic protein expression in the corpus callosum, and ventriculomegaly, as well as learning alterations were measured to determine the extent to which NIST SRM 1650b would induce developmental neurotoxicity.ResultsTwenty-four hours following exposure significant increases in glial-fibrillary acidic protein (GFAP) in the corpus callosum and cortex of exposed male mice were present. Additionally, the body weights of juvenile and early adult diesel particle exposed males were lower than controls, although the difference was not statistically significant. No treatment-related differences in males or females on overall locomotor activity or temporal learning during adulthood were observed in response to diesel particulate exposure.ConclusionWhile some sex and regional-specific pathological alterations in GFAP immunoreactivity suggestive of an inflammatory reaction to SRM 1650b were observed, the lack of protracted behavioral and pathological deficits suggests further clarity is needed on the developmental effects of diesel emissions prior to enacting regulatory guidelines.

Dataset Information

A randomized cross-over study of inhalation of diesel exhaust, hematological indices, and endothelial markers in humans.

Background

Methods

Results

Conclusions

Publications

A randomized cross-over study of inhalation of diesel exhaust, hematological indices, and endothelial markers in humans.

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