2010 Progress Report: Human Clinical Studies of Concentrated Ambient Ultrafine and Fine Particles

EPA Grant Number: R832415C003
Subproject: this is subproject number 003 , established and managed by the Center Director under grant R832415
(EPA does not fund or establish subprojects; EPA awards and manages the overall grant for this center).

Center: Rochester PM Center
Center Director: Oberdörster, Günter
Title: Human Clinical Studies of Concentrated Ambient Ultrafine and Fine Particles
Investigators: Frampton, Mark W. , Gelein, Robert , Oakes, David , Phipps, Richard , Utell, Mark J. , Zareba, Wojciech
Institution: University of Rochester
EPA Project Officer: Chung, Serena
Project Period: October 1, 2005 through September 30, 2010 (Extended to September 30, 2012)
Project Period Covered by this Report: June 30, 2009 through July 1,2010
RFA: Particulate Matter Research Centers (2004) RFA Text |  Recipients Lists
Research Category: Health Effects , Air

Objective:

The overall objective of our current and planned studies is to determine the pulmonary and cardiovascular effects of exposure to ultrafine and fine particulate matter (PM). The clinical studies in healthy humans and susceptible individuals proposed in this research core focus on the effects of ambient ultrafine and fine particles on three major determinants of adverse cardiac events: 1) blood coagulation induced by effects on platelets and circulating microparticles; 2) cardiac output; and 3) cardiac rhythm and repolarization.

Our overall hypothesis is that inhalation of ambient PM causes small but measurable changes in coagulation and cardiovascular function that help explain the cardiovascular effects of PM exposure. We further hypothesize that the cardiovascular effects are determined by the ability of PM to generate reactive oxygen and nitrogen species, and are more pronounced in subjects with type 2 diabetes and in subjects with genetically determined reduced antioxidant defenses. Inhaled ultrafine particles increase the burden of reactive oxygen species to the endothelium. Endothelial activation and vasoconstriction increase platelet adherence and release of thromboxane, activate and prolong the transit time of blood leukocytes, and deplete vascular nitric oxide (NO). Particles may also have direct effects on platelets and leukocytes. Vascular injury triggers release of procoagulant microparticles into the blood, and initiation of coagulation. In collaboration with the Vascular and Inflammation Facility Core, we measure the effects of inhaled ambient fine PM on platelet number, phenotype, and function, and quantitate intravascular microparticles derived from platelets and endothelial cells. In collaboration with the Cardiac Core, we use noninvasive monitoring methods to measure exposure effects on cardiac output, rhythm, and repolarization.

Progress Summary:

  1. Human clinical exposures to concentrated ambient ultrafine particles

    Data analyses have been completed for this study, and manuscript preparation is underway. Design details and findings of this study were presented in our previous progress report.

  2. Ultrafine Particle Effects on Dendritic Cells in Asthma (ASTHMACON)

    We have completed a pilot study that was funded in part by the Rochester EPA Center. This study examines the effects of air pollution exposure on innate immunity in susceptible subjects. We hypothesized that, in susceptible asthmatic subjects, inhalation of concentrated ambient UFP will: 1) stimulate the recruitment and maturation of blood-derived dendriticcells (DC), 2) increase DC responses to challenge with bacterial products or PM, and 3) enhance the ability of DC to drive a Th2-type immune response. Furthermore, we hypothesized that these effects are most pronounced in those with genetic polymorphisms that reduce anti-oxidant defenses, specifically people who have the null variant of the glutathione Stransferase M1 (GSTM1) gene.

    Our goal in this pilot study was to recruit and study 10 patients with asthma, 5 of whom were GSTM1 sufficient and 5 who were GSTM1 null. Subjects were exposed to concentrated ambient ultrafine particles on one occasion, and clean, filtered air on another occasion, at rest. Exposures were separated by at least 3 weeks. At baseline and 3 and 24 hours after exposure, blood was obtained, spirometry was performed, and exhaled breath compensate was collected. Blood was subjected to a detailed flow cytometric characterization of circulating dendritic cells and monocytes. In addition, blood monocytes were cultured in vitro and stimulated to develop DC phenotypes. These blood derived dendritic cells were then challenged in vitro.

    The preliminary findings from this study were presented at the AAAR meeting and the American Thoracic Society International Conference, both in 2010. Our findings demonstrate the feasibility of studying circulation DC populations in human subjects with specific genetic polymorphisms, and indicate that UFP exposure may cause subtle alterations in some subsets of monocytes, eosinophils, and circulating DCs. There were no effects on symptoms or lung function.

  3. Cardiovascular Effects of Ultrafine Particles in Genetically Susceptible Subjects (CUSP)

Our human clinical studies of UFP inhalation have shown evidence for acute effects on vascular function. We hypothesize that the acute vascular effects of UFP exposure are a consequence of reduced NO bioavailability. We have developed a new approach to test this hypothesis, involving the measurement of nitric oxide metabolites in both arterial and venous blood. Specifically, we hypothesize that exposure to ultrafine particles will deliver a burden of reactive oxygen species to the pulmonary vascular endothelium, altering the delivery of NO, specifically as nitrite, to the systemic vasculature. We expect that UFP exposure will alter the artery-to-vein nitrite gradient which is normally present.

We have now initiated a new study, jointly funded by this center and by the NIH, to test this hypothesis in healthy subjects. Two groups of subjects will be selected for specific genetic polymorphisms expected to increase susceptibility to oxidative stress, and these two groups will be compared with a third group that is "wild type" for each of these polymorphisms.

For the EPA-funded part of this study, we are going to add a new, separate set of analyses that was not part of the NIH application, but is highly relevant to the whole issue of PM effects on vascular function and NO bioavailability. We will be doing a set of analyses to detect subtle effects on the membrane of circulating red blood cells. Our hypothesis is that inhaled UFP or their products cause subtle alterations in the RBC membrane that shift the dynamics of RBC transport and storage of nitrite and other NO metabolites. This study is now under way. We have recruited 15 subjects to the study, and six subjects have completed both air and UFP exposures.

These studies will provide important new information about the cardiac and vascular effects of exposure to UFP, and will test specific mechanisms for these effects. In addition, we will test the hypothesis that specific genetic polymorphisms confer increased susceptibility to UFP effects.

These studies are highly relevant to the overall Center goal of understanding the cardiovascular effects of UFP exposure.

Findings from these studies will improve our understanding of the health effects of breeding ambient UFP, and will help to inform the development of rational ambient air quality standards.

Sub-Project Title: “Ultrafine Particles and Cardiac Responses: Evaluation in a Cardiac Rehabilitation Center

Investigators: Mark J. Utell (PI); Philip Hopke and William Beckett (Co-PIs)

Co-Investigators: David Oakes; Wojciech Zareba; Mark Frampton; John Bisognano; Annette Peters

Objective(s) of the Research Project:

University of Rochester investigators in Rochester, New York have conducted a study evaluating the association between air pollution (with particular emphasis on ultrafine particles) and several cardiovascular parameters. The study population consisted of 75 subjects undergoing cardiac rehabilitation after recent acute coronary syndrome (myocardial infarction, unstable angina). The enrolled subjects were involved in two rehabilitation sessions per week consisting of 20-45 minutes of exercise over a 10-week period. Cardiovascular status, blood pressure, and continuous Holter ECG recordings were applied during each session. The ECG recordings included resting supine periods prior to supervised exercise and after exercise (recovery period) as well as during the exercise period. In addition, venous blood samples were collected weekly for fibrinogen, C-reactive protein and complete blood counts. Measurements of ambient ultrafine particles were monitored continuously within and outside of the cardiac rehabilitation center. The particle size distribution data from the Cardiac Rehabilitation Center (indoors and outdoors) and at the NYS DEC site were collected to support the clinical studies of heart rate, rhythm and ischemia in the rehabilitation patients.

Progress Summary/Accomplishments:

A. Subject Demographics: 76 subjects were enrolled in the protocol. Five patients discontinued participation in the study for different reasons: one due to job location change; one for orthopedic complications (2 males non-completers); and three due to poor attendance (3 females). Of the 71 participants (49 male, 22 female; mean age = 60 years and range = 36 to 80 years), 95% completed the entire protocol.

Inclusion criteria required participants to have stable coronary artery disease, be enrolled in the University of Rochester Medical Center rehabilitation program, and live within 10 miles of the central monitoring site or the cardiac rehab center. Participants were current non-smokers and remained in the study area during the entire study period. Patients with atrial fibrillation, pacemakers, bundle-branch blocks, and type 1 diabetes were excluded. Annual approval for the protocol was obtained from the University of Rochester Research Subjects Review Board (RSRB).

B. Particle Measurements: Ultrafine particle exposures within and without the cardiac rehab center were monitored continuously. The particle size distribution data (Table 1) from the Cardiac Rehabilitation Center (indoors and outdoors) and at the NYS DEC site have been collected to support the clinical studies of heart rate variability and inflammatory markers in the blood of rehabilitation patients. In addition, 30 patients completed 48 hour home monitoring (2 day averages = 9.2 x 103 +/- 6.8 x 103 p/cm3), with 16 patients performing particle count monitoring in their car to and from the rehab facility (1.5 x 104 +/- 8.2 x 103 p/cm3) using a portable nuclei counter (TSI model 3781).

Table 1. Hourly ultrafine particle count concentrations (x103 p/cm3) (Sept. 06 – Sept. 09).

Sept.-Dec. 2006

10-50 nm

50-100 nm

100-500 nm

10-500 nm

% Rpted.

Rehab Indoor

0.48 +/- 0.41

0.41 +/- 0.32

0.39 +/- 0.31

1.29 0.85

98.4

Rehab Outdoor

2.71 +/- 2.03

1.55 +/- 1.18

1.06 +/- 0.78

5.32 3.35

98.4

DEC Outdoor

3.24 +/- 2.48

1.64 +/- 1.41

1.09 +/- 0.86

5.97 4.05

78.0

2007

10-50 nm

50-100 nm

100-500 nm

10-500 nm

% Rpted.

Rehab Indoor

0.85 +/- 1.7

0.61 +/- 0.61

0.53 +/- 0.50

1.98 2.25

88.3

Rehab Outdoor

2.94 +/- 3.51

1.49 +/- 1.57

1.01 +/- 0.80

5.44 4.87

88.3

DEC Outdoor

4.00 +/- 3.64

1.87 +/- 1.44

1.14 +/- 0.88

7.01 4.84

96.8

2008

10-50 nm

50-100 nm

100-500 nm

10-500 nm

% Rpted.

Rehab Indoor

0.96 +/- 2.0

0.65 +/- 0.72

0.72 +/- 0.72

2.29 2.76

70.7

Rehab Outdoor

2.89 +/- 3.48

1.35 +/- 1.12

1.30 +/- 1.15

5.55 4.63

70.7

DEC Outdoor

3.20 +/- 2.76

1.48 +/- 1.14

0.95 +/- 0.72

5.64 3.79

95.8

Jan.-Sept. 2009

10-50 nm

50-100 nm

100-500 nm

10-500 nm

% Rpted.

Rehab Indoor

0.70 2.0

0.45 +/- 0.54

0.36 +/- 0.39

1.51 2.94

92.9

Rehab Outdoor

2.38 2.93

1.09 +/- 0.94

0.76 +/- 0.59

4.23 3.64

92.9

DEC Outdoor

3.23 2.97

1.43 +/- 1.08

1.0 +/- 0.87

5.70 4.01

96.6

We are examining the relationship between the ambient ultrafine particle size distributions at the Rehabilitation Facility and the measurements at the NYSDEC site during a one-year period. The data have been collected and the analyses are underway. The goal is to examine the differences in ultrafine particle counts in 2 areas that are closely located.

C. Cardiac Rehabilitation and Routine Parameters:

During each cardiac rehabilitation session, each subject had measured heart rate and blood pressure before exercise, at peak exercise, and after exercise. Apart from presenting these measures, differences between peak exercise and pre-exercise and between peak and postexercise were also reported.

ECG Recordings: The ECG recordings for this study were acquired and analyzed using a 3-lead (V2, V5, aVF) Vision Premier Burdick Holter System (Cardiac Science, Bothell, WA) and custom-made programs at the University of Rochester Medical Center. As part of a 2-3-hour 3-lead Holter recording, but prior to each exercise session, a 10-minute resting ECG was acquired to obtain baseline (pre-exercise) information regarding several ECG parameters without influence of exercise. After completion of the resting 10-min recording, subjects were undergoing the routine exercise rehabilitation program with continuous holter recording. Subsequently a 10-minute resting recording prior to discharge was repeated.

ECG Parameters: The entire duration of Holter ECG recording served to obtain the following ECG parameters:

  • mean NN interval mean RR interval based on normal-to-normal beats while excluding nonsinus beats
  • SDNN – standard deviation of normal-to-normal intervals representing measures of overall heart rate variability
  • rMSSD – root mean square of successive differences
  • TS – heart rate turbulence slope, heart arte derived parameter reflecting baroreflex sensitivity
  • DC – deceleration capacity – measure of heart rate dynamics
  • ST depression ≥1mm for at least 1 minute – reflecting myocardial ischemia in any of three leads
  • Number of VPBs – number of ventricular premature beats in entire recording
  • Number of APBs – number of atrial premature beats in entire recording

In addition, resting 10-minute resting recordings were used to evaluate:

  • mean NN interval,
  • SDNN,
  • rMSSD,
  • HF – high-frequency component from frequency-domain HRV analysis reflecting parasympathetic modulation of the heart,
  • QTc duration, reflecting overall duration of ventricular repolarization
  • Tp-Te (Tpeak – T-end) duration, late repolarization duration that might reflect heterogeneity of repolarization.

D. Approaches to the Statistical Analyses:

  1. General Strategy: A key strength of this study is the availability of longitudinal measurements on each subject, corresponding to their successive visits to the rehabilitation center. This design feature allows each subject to be used as his or her own control. Differences between subjects may be eliminated by stratification, corresponding to the use of a fixed effects analysis of variance model, or by explicitly modeling subject effects as random. The latter approach is necessary for examining the influence of factors that do not change from one visit to another, for example the gender of the subject. The former approach gives greater statistical power to address the primary hypotheses of the study relating to the influence of the UFP concentrations, which do change from visit to visit. In the simplest case, the fixed approach corresponds to a simple paired t-test, comparing responses of the same subject during periods of relatively high and low exposure to ultrafine particles. More commonly analysis of covariance (PROC GLM) is being used, with the subjects entered as fixed effects and ultrafine particle exposure as a continuous variable. Models with subjects entered as random effects are being used to assess the generalizability of the findings to other populations.
  2. Multivariable Analysis: In view of the complex relationship between UFP levels and weather (which may independently influence cardiac responses) we are examining multivariable models including effects of variations in temperature, PM 2.5, SO2 and CO. In subsequent work we plan to explore the functional forms of the potential confounding effects using penalized spline methodology.
  3. Sample size: The proposed net sample size of 75 subjects will allow detection of an effect size of 33% (ratio of mean difference to standard deviation. of difference) in a response variable with 80% power, using a two-sided test with alpha level = 0.05.
  4. Progress to date: Data on cardiac responses including perceived exertion, changes in heart rate from pre-exercise to peak and to post exercise, associated changes in systolic and diastolic blood pressure, and white blood count have been examined on the 76 subjects who entered the program. Correlations have been assessed with measures of ultrafine particle exposure at the corresponding visit. Separate linear models were fitted to each cardiac response measure for each measure of exposure, including the indoor and outdoors particle counts (< 100 and >100). For the outdoor counts the data were accumulated over 24 hour periods up to the time of the appointment, with lags from zero to 4 days. The total exposure for first day was also split into that 6 accumulated in the 6 hours preceding the appointment and that accumulated in the prior 18 hours. Unfortunately indoor and outdoor measurements were not available on certain dates at the Cardiac Center due to problems with the sampling apparatus. There were two periods of machine down time for repair by the manufacturer. (12/14/07-2/12/08 & 4/4/08-5/23/08). During these times the data was imputed from outdoor particle data being collected in the same manner at the DEC site approximately 5 km away. A "least squares" method was used to calculate a straight line that best fit the data. Values along the linear trend were then used to impute the missing data from the Cardiac site using the DEC data during those time periods. The relationship between the outdoor and indoor was also analyzed for the same time period in order to estimate the indoor data during the down times.

Because the exposure data were highly skewed, they were log-transformed. To ease interpretability of the effect size estimate, the pollutant data were standardized by dividing each value by the interquartile range of the corresponding distribution, so that each coefficient compares response of a subject at the 25’the percentile of the exposure measure to that of a subject at the 75’th percentile. The primary analysis included adjustment for subject and visit number, both as fixed effects. Visit number was included in the analysis (as a categorical variable) to allow for the possibility of systematic changes in the cardiac parameters over time, as the subject progressed through the rehabilitation program. Also, for the outside measures, we assessed the possible confounding effects of atmospheric temperature, PM25, SO2 and CO by fitting a second model including these additional terms as well as the UFP exposure measure.

A similar strategy was pursued with the cardiac outcome measures derived from the Holter recordings, including Mean NN interval the, rMSSD (r.m.s. of successive NN differences), HF (High Frequency Component), ST-depression, VTotal (Ventricular Premature Beats), SVTotal (Atrial Premature Beats) Heart Rate Turbulence, Deceleration Capacity and TpTe. In addition to these analyses using SAS PROC GLM in which the subjects are treated as fixed effects we are proceeding with analyses using SAS proc MIXED in which the subjects effects are allowed to be random.

Future Activities:

  • UPCON study (healthy subjects inhaling CUFP): complete measurements of soluble markers of inflammation and coagulation; prepare manuscripts.
  • UPASTHMA study (genetically susceptible asthmatic subjects inhaling CUFP): complete data analysis, prepare manuscript.
  • CUSP study (Cardiovascular Effects of Ultrafine Particles in Genetically Susceptible Subjects): Complete subject recruitment and exposures.
  • Data analyses are ongoing and a manuscript describing the cardiac findings is planned.


Journal Articles on this Report : 5 Displayed | Download in RIS Format

Other subproject views: All 57 publications 44 publications in selected types All 41 journal articles
Other center views: All 190 publications 156 publications in selected types All 143 journal articles
Type Citation Sub Project Document Sources
Journal Article Hildebrandt K, Ruckerl R, Koenig W, Schneider A, Pitz M, Heinrich J, Marder V, Frampton M, Oberdorster G, Wichmann HE, Peters A. Short-term effects of air pollution: a panel study of blood markers in patients with chronic pulmonary disease. Particle and Fibre Toxicology 2009;6:25. R832415 (2009)
R832415 (2010)
R832415 (2011)
R832415 (Final)
R832415C002 (2009)
R832415C002 (2010)
R832415C002 (2011)
R832415C003 (2010)
R832415C003 (2011)
R832415C004 (2010)
R832415C004 (2011)
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  • Journal Article Shah AP, Pietropaoli AP, Frasier LM, Speers DM, Chalupa DC, Delehanty JM, Huang L-S, Utell MJ, Frampton MW. Effect of inhaled carbon ultrafine particles on reactive hyperemia in healthy human subjects. Environmental Health Perspectives 2008;116(3):375-380. R832415 (2007)
    R832415 (2008)
    R832415 (2010)
    R832415 (2011)
    R832415 (Final)
    R832415C003 (2006)
    R832415C003 (2010)
    R832415C003 (2011)
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  • Journal Article Stewart JC, Villasmil ML, Frampton MW. Changes in fluorescence intensity of selected leukocyte surface markers following fixation. Cytometry Part A 2007;71A(6):379-385. R832415 (2007)
    R832415 (2008)
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    R832415 (2011)
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    R832415C003 (2006)
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    R832415C003 (2011)
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  • Journal Article Thurston GD, Bekkedal MY, Roberts EM, Ito K, Pope III CA, Glenn BS, Ozkaynak H, Utell MJ. Use of health information in air pollution health research:past successes and emerging needs. Journal of Exposure Science and Environmental Epidemiology 2009;19(1):45-58. R832415 (2010)
    R832415 (2011)
    R832415 (Final)
    R832415C003 (2010)
    R832415C003 (2011)
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  • Journal Article Zareba W, Couderc JP, Oberdorster G, Chalupa D, Cox C, Huang L-S, Peters A, Utell MJ, Frampton MW. ECG parameters and exposure to carbon ultrafine particles in young healthy subjects. Inhalation Toxicology 2009;21(3):223-233. R832415 (2008)
    R832415 (2009)
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    R832415 (2011)
    R832415 (Final)
    R832415C002 (2010)
    R832415C002 (2011)
    R832415C003 (2010)
    R832415C003 (2011)
    R832415C004 (2009)
    R832415C004 (2010)
    R832415C004 (2011)
    R827354 (Final)
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  • Supplemental Keywords:

    RFA, Health, Scientific Discipline, PHYSICAL ASPECTS, Air, particulate matter, Health Risk Assessment, Risk Assessments, Physical Processes, atmospheric particulate matter, atmospheric particles, long term exposure, acute cardiovascular effects, airway disease, exposure, human exposure, ambient particle health effects, atmospheric aerosol particles, ultrafine particulate matter, PM, aersol particles, cardiovascular disease

    Progress and Final Reports:

    Original Abstract
  • 2006 Progress Report
  • 2007 Progress Report
  • 2008 Progress Report
  • 2009 Progress Report
  • 2011 Progress Report
  • Final Report

  • Main Center Abstract and Reports:

    R832415    Rochester PM Center

    Subprojects under this Center: (EPA does not fund or establish subprojects; EPA awards and manages the overall grant for this center).
    R832415C001 Characterization and Source Apportionment
    R832415C002 Epidemiological Studies on Extra Pulmonary Effects of Fresh and Aged Urban Aerosols from Different Sources
    R832415C003 Human Clinical Studies of Concentrated Ambient Ultrafine and Fine Particles
    R832415C004 Animal models: Cardiovascular Disease, CNS Injury and Ultrafine Particle Biokinetics
    R832415C005 Ultrafine Particle Cell Interactions In Vitro: Molecular Mechanisms Leading To Altered Gene Expression in Relation to Particle Composition