2015 Progress Report: Simulated Roadway Exposure Atmospheres for Laboratory Animal and Human Studies

EPA Grant Number: R834796C002
Subproject: this is subproject number 002 , established and managed by the Center Director under grant R834796
(EPA does not fund or establish subprojects; EPA awards and manages the overall grant for this center).

Center: University of Washington Center for Clean Air Research
Center Director: Vedal, Sverre
Title: Simulated Roadway Exposure Atmospheres for Laboratory Animal and Human Studies
Investigators: McDonald, Jacob D.
Institution: Lovelace Respiratory Research Institute
EPA Project Officer: Callan, Richard
Project Period: December 1, 2010 through November 30, 2015 (Extended to November 30, 2017)
Project Period Covered by this Report: August 1, 2014 through July 31,2015
RFA: Clean Air Research Centers (2009) RFA Text |  Recipients Lists
Research Category: Health Effects , Air

Objective:

Objectives/Hypothesis: Traffic-related emissions are associated with the incidence and progression of acute and chronic cardiovascular sequelae in human population studies; however, the causal components, subsequent chemical transformation of these components, and their associated toxicity on the cardiovascular system have not yet been determined. Project 2 is in progress to develop atmospheres, with the primary objective of simulating environments containing key components of roadway emissions and the products of environmental factors that transform them. Previous, current and future exposures are designed to determine air contaminants (or components) that cause or potentiate the toxicity of roadway emissions or confound interpretations based on roadway proximity alone.

Approach: This project will generate and characterize multiple complex roadway mixtures for subsequent animal and human exposure-related toxicology studies. In Aim 1, we will develop and characterize laboratory-generated exposure atmospheres simulating the key components of near-roadway exposures, including transformed emissions and coexposures. In Aim 2, we will conduct inhalation exposures of laboratory animals (as described in Project 3). We had planned to include as Aim 3 a study of inhalation exposures of human subjects in an effort to compare significant pathophysiological findings from our animal model exposures to responses in humans. Due to human subjects issues related to Project 4, Aim 3 was dropped.

Expected Results: Results from these studies will identify key components, as well as the most potent combinations, of urban roadway and background copollutants that result in toxicological responses in the cardiovascular system of rodents.

Progress Summary:

Over the past year we have focused on continuing to evaluate the endothelial cell and myography assays with Project 3 and to extend additional endpoints to confirm the cardiovascular response of putative pollutants. These results are described in Project 3. Project 2 developed novel atmospheres that continue to evaluate the role of gas-particle interactions and the particle size on the toxicity of inhaled mixtures. This was done by developing novel atmospheres that focus on better understanding the gaseous-particle and size components of motor vehicle exhaust (MVE). Atmospheres included:

  • MVE minus gases: A denuder that removes gas-phase organics was employed.
  • MVE minus semivolatile organics (SVOCs): catalytic stripper with catalyst that removes gaseous and semivolatile organics from the aerosol was applied to the test atmosphere to evaluate gases/organic particles versus solid particle residuals.
  • MVE benchmark
  • Woodsmoke

Based on the previous studies of multiple test atmospheres and the response in the endothelial cell assays, it was determined that the two most potent atmospheres were MVE and woodsmoke. As a result, we prioritized these test atmospheres for the longer-term studies that were performed this year. These include the studies with the test atmospheres developed above. The samples from these studies were generated using the Lovelace Repository Research Institute (LRRI) protocols defined below and the overall study design in terms of the distribution of samples to the University of California, Los Angeles (UCLA), and the University of New Mexico (UNM).

  • FY15-023A——February 2015. 132 ApoE-/- mice + HFD– exposed to woodsmoke, MVE100, MVE300, MVE-SVOC, MVE-gases for 50 days
  • FY15-023B——July 2015. 24 C57Bl/6 mice exposed to woodsmoke.

Protocol for 50-day exposures:

Atmospheres based on results from 1d serum bioactivity assay with both ApoE and C57 mice, 5 percent serum on mCECs. Myography suggested to study the following atmospheres:

ApoE-/- mice, male, 6 weeks at beginning of study. Diet HT88137 for a week prior. 6 hours/day x 50 days, 300 µg PM/m3 equivalents.

  • Filtered air
  • MVE
  • MVE-PM (catalytic stripper)
  • Woodsmoke

For UCLA: N = 10 (40 mice total)

  • Serum——HDL
  • Liver——cholesterol endpoints
  • Lung——inflammatory endpoints
  • BALF (lipidomics)
  • Gut —(Lund)
  • Aorta——en face ORO staining
  • Heart——rv/lvs, sectioning of aortic outflow for histopath

For UNM: N = 12 (48 mice total)

  • Serum——myography
  • Liver——cholesterol endpoints
  • Lung——inflammatory endpoints, histo
  • BALF (cell counts, diffs, total protein)
  • Adipose—maybe for UCLA
  • Aorta——en face ORO staining
  • Heart——rv/lvs, sectioning of aortic outflow for histopath, freeze RV and remaining LVS for PCR

The study atmospheres for the MVE and MVE minus SVOC are shown below in Table 1 below (only last week shown). Note that the catalytic stripper oxidized the CO to CO2, providing the benefit of removing CO along with the gaseous and semivolatile material for these studies. The analysis of the biological response from these studies is underway in collaboration with Project 3.

Table 1. Study atmospheres for MVE and MVE minus SVOC

Date

Chamber 2-MVE

100 µg

BOX for GASES(Denuder)-

300 µg

BOX for SVOC(Stripper)-

300 µg

Chamber 5-MVE

300 µg

NOx

CO Target ppm

Particle Mass Target 100 μg/m3

NOx

CO Target ppm

Particle Mass Target 300 μg/m3

NOx

CO Target ppm

Particle Mass Target 300 μg/m3

NOx

CO Target ppm

Particle Mass Target 300 μg/m3

4/2/2015

3

8

76

9

29

301

18

1

353

14

19

233

4/3/2015

4

14

113

11

30

299

22

1

370

14

32

329

4/4/2015

5

13

116

17

50

335

27

1

325

14

34

310

4/5/2015

2

11

96

9

37

361

14

1

298

14

44

305

4/6/2015

2

8

130

12

42

312

16

2

313

14

189

296

4/7/2015

3

12

97

10

32

319

20

1

319

14

70

287

4/8/2015

2

10

91

6

28

298

9

1

289

14

25

228

Average

9

14

121

15

36

318

25

1

314

18

50

311

Std Deviation

9

12

108

6

12

49

12

3

40

7

34

35

% CV

106

86

89

37

33

15

47

219

13

37

67

11

% Target

9

14

121

15

36

106

25

1

105

18

50

104

New Atmosphere Development

Follow-on atmospheres have been under development to better study the impact of particle size and surface area in terms of biological response. The goal is to evaluate the role of gas interactions with particulate matter (PM) as it relates to the size/surface area of the particles with the design described below. These studies are starting in August 2015.

MVE surface area assessment (study initiating in August 2015)

Comparing interaction of MVE gases with different size PM—study design

  • Filtered Air
  • MVE ultrafine (UF) particles: MVE generated with engines and then gases removed
  • MVE Fine (F) particles: resuspended MVE particles in larger size range generated (no gases present)
  • MVE UF + gases ** (gases added to mixture after removal)
  • MVE F + gases (gases added to mixture)

1 day (6 hours, immediate sac)——C57, serum collection, lavage (cell count, diffs, total protein), freeze lungs. N = 10

  • 50 day (6 hours/day)—ApoE, HT88137 diet
  • Serum
  • Aorta
  • Heart
  • Gut (Lund)
  • Liver
  • Brain (1/2 frozen, half fixed in paraformaldehyde)
  • Lung
  • BALF (cell count, diffs, total protein, save for lipidomics)

Aerosol Generation Data for Atmosphere Development—summary notes of MVE 1-2 µm generation

  • MVE (300 µg/m3) used earlier is all Ultrafine.
  • With MVE there is nothing on APS from H-1000 sample (H-1000 is used to pull sample for smaller lexan chambers).
  • Using a Wright dust feeder (WDF) with deposited material from the diesel exhaust line, larger particles can be generated (as measured by APS).
  • We used a cyclone to get rid of most of the particles above 3 µm.
  • Using Wright dust feed aerosol generator, we still see ultrafines on FMPS with a similar size distribution (Figure 1 below); however, their concentration is lower compared to a similar concentration (300 µg/m3) MVE (Figure 2 and Figure 3).
  • APS data—MVE versus WDF. MVE concentrations are negligible (leakage issues in lexan chamber).
  • APS data for WDF. The ratio of number, surface area and mass concentration for < 0.5 um and > 0.5 um particles is very small.


Figure 1. MVE particulate material generated with wright dust feeder to reach 1––2 microns.
PM was collected from dilution tunnel, harvested and reaerosolized to achieve larger particle size.


Figure 2. Difference in particle number and surface area concentration in MVE chamber (blue) versus resuspended MVE PM (red).
MVE has much higher number, smaller particle size and larger surface area compared to larger material that is resuspended.


Figure 3. Number concentration/surface area for particles larger than 0.5 microns measured by APS.
Resuspended MVE particle number is higher in the higher particle size.

Future Activities:

The next round of studies will continue the followup on long-term assays, confirming the effect differentials related to surface area and gas-particle interactions.


Journal Articles on this Report : 3 Displayed | Download in RIS Format

Other subproject views: All 13 publications 5 publications in selected types All 5 journal articles
Other center views: All 172 publications 76 publications in selected types All 75 journal articles
Type Citation Sub Project Document Sources
Journal Article Lund AK, Doyle-Eisele M, Lin Y-H, Arashiro M, Surratt JD, Holmes T, Schilling KA, Seinfeld JH, Rohr AC, Knipping EM, McDonald, JD. The effects of α-pinene versus toluene-derived secondary organic aerosol exposure on the expression of markers associated with vascular disease. Inhalation Toxicology 2013;25(6):309-324. R834796 (2013)
R834796 (2014)
R834796 (2015)
R834796C002 (2015)
R834796C003 (2013)
  • Abstract from PubMed
  • Abstract: Taylor & Francis-Abstract
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  • Journal Article Mauderly JL, Kracko D, Brower J, Doyle-Eisele M, McDonald JD, Lund AK, Seilkop SK. The National Environmental Respiratory Center (NERC) experiment in multi-pollutant air quality health research: IV. Vascular effects of repeated inhalation exposure to a mixture of five inorganic gases. Inhalation Toxicology 2014;26(11):691-696. R834796 (2014)
    R834796 (2015)
    R834796C002 (2015)
    R834796C002 (2016)
  • Abstract from PubMed
  • Abstract: Taylor & Francis-Abstract
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  • Journal Article Oppenheim HA, Lucero J, Guyot A-C, Herbert LM, McDonald JD, Mabondzo A, Lund AK. Exposure to vehicle emissions results in altered blood brain barrier permeability and expression of matrix metalloproteinases and tight junction proteins in mice. Particle and Fibre Toxicology 2013;10:62. R834796 (2014)
    R834796 (2015)
    R834796C002 (2015)
    R834796C002 (2016)
  • Full-text from PubMed
  • Abstract from PubMed
  • Associated PubMed link
  • Full-text: BioMed Central-Full Text PDF
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  • Abstract: BioMed Central-Abstract & Full Text HTML
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  • Supplemental Keywords:

    diesel, gasoline engine, inhalation toxicology, Health, Scientific Discipline, Air, ENVIRONMENTAL MANAGEMENT, Air Quality, air toxics, Health Risk Assessment, Risk Assessments, mobile sources, Environmental Monitoring, Biochemistry, Risk Assessment, ambient air quality, atmospheric particulate matter, particulate matter, aerosol particles, air pollutants, motor vehicle emissions, vehicle emissions, air quality models, motor vehicle exhaust, airway disease, bioavailability, air pollution, particle exposure, atmospheric aerosols, ambient particle health effects, vascular dysfunction, cardiotoxicity, atmospheric chemistry, exposure assessment

    Relevant Websites:

    University of Washington Center for Clear Air Research (UW CCAR) Exit

    Progress and Final Reports:

    Original Abstract
    2011 Progress Report
    2012 Progress Report
    2013 Progress Report
    2016 Progress Report


    Main Center Abstract and Reports:

    R834796    University of Washington Center for Clean Air Research

    Subprojects under this Center: (EPA does not fund or establish subprojects; EPA awards and manages the overall grant for this center).
    R834796C001 Exposure Mapping – Characterization of Gases and Particles for ExposureAssessment in Health Effects and Laboratory Studies
    R834796C002 Simulated Roadway Exposure Atmospheres for Laboratory Animal and Human Studies
    R834796C003 Cardiovascular Consequences of Immune Modification by Traffic-Related Emissions
    R834796C004 Vascular Response to Traffic-Derived Inhalation in Humans
    R834796C005 Effects of Long-Term Exposure to Traffic-Derived Particles and Gases on Subclinical Measures of Cardiovascular Disease in a Multi-Ethnic Cohort