2001 Progress Report: Asthma Susceptibility to PM2.5

EPA Grant Number: R827351C003
Subproject: this is subproject number 003 , established and managed by the Center Director under grant R827351
(EPA does not fund or establish subprojects; EPA awards and manages the overall grant for this center).

Center: EPA NYU PM Center: Health Risks of PM Components
Center Director: N/A
Title: Asthma Susceptibility to PM2.5
Investigators: Thurston, George D. , Reibman, Joan
Institution: New York University School of Medicine
EPA Project Officer: Chung, Serena
Project Period: June 1, 1999 through May 31, 2005 (Extended to May 31, 2006)
Project Period Covered by this Report: June 1, 2001 through May 31, 2002
RFA: Airborne Particulate Matter (PM) Centers (1999) RFA Text |  Recipients Lists
Research Category: Air Quality and Air Toxics , Particulate Matter , Air

Objective:

The objectives of this research project are to investigate which particulate matter (PM) component(s) and PM mechanisms affect asthmatics most strongly and to prospectively follow a cohort of nonsmoker asthmatics and evaluate PM effects on their health status. The ultimate goals are to: (1) establish technical and operational feasibility for a combined epidemiological/clinical research study; (2) demonstrate associations between specific PM components and commonly occurring asthma exacerbations attributable to air pollution; and (3) develop hypotheses regarding the mechanisms of the PM health effects association that can be tested via toxicological studies by other researchers in the New York University (NYU)-U.S. Environmental Protection Agency PM Research Center (e.g., via controlled exposure studies). Moreover, the results of this study may be used as preliminary results for the funding of a follow-up study in this already characterized population.

Progress Summary:

Originally, we recruited patients during 1999-2000 for our cohort of adult nonsmoking asthmatic subjects willing to be followed by prospective monitoring on days following low versus high PM2.5 concentrations. Because of difficulties in the first summer (of 1999) in inducing sputum in asthma patients, we believed that we needed to improve our induced sputum technique. Approval was obtained to induce-sputum from normal volunteers, and 10 subjects were recruited and duplicate procedures were performed on these subjects.

Subjects with asthma were recruited from the previous summer cohort, clinics, and local advertisements. Participants were asked to be "on call" for 1-day notice to come for four visits, two "High" and two "Low" visits. These correspond to 2-day lag visits from the defined day. Subjects underwent pulmonary function testing (PFT), blood draw, and premedication with bronchodilator followed by sputum induction. "High" and "Low" PM days were defined based on the analysis of previous data: "High" = PM10 > 40 µg/m3, while "Low" = PM10 < 20 µg/m3.

Sputum induction was performed by use of increasing concentrations of hypertonic saline that were inhaled (3 percent, 4 percent, 5 percent) for 7 minutes via an ultrasonic nebulizer. Subjects underwent spirometry for measurement of FEV1 at the start of the procedure and after each period of inhalation. If the FEV1 dropped 20 percent, the procedure was terminated. After each saline inhalation, subjects coughed into a sterile container. Sputum plugs were separated from saliva and examined within 2 hours. After weighing, sputum plugs were dissolved in dithiothreitol (0.1 percent) and phosphate-buffered saline. The suspension then was filtered and a total nonsquamous cell count was performed. Cell viability was determined by trypan blue exclusion. Cytospins were prepared, stained with Wright’s stain, and a differential cell count of nonsquamous cells types was performed. Metachromatic cells were detected in preparations stained with toluidine blue. Cell pellets also were prepared for RNA analysis.

At that time, sputum samples were successfully collected on both normal subjects (n = 10) and from subjects with asthma (n = 11). In addition, 44 blood serum samples were collected. This was deemed not yet sufficient for the originally envisioned high versus low PM day comparisons. However, these samples can provide a basis for evaluating which biomarkers can be successfully used to assess PM-induced effects in the study population. For example, as shown in Figure 1, preliminary findings from several of these samples have already demonstrated the ability to detect and measure inflammatory cells in sputum samples as well as the presence of elevated levels of eosinophils. In addition, sputum samples were analyzed for the presence of dendritic cells (CD1a+), and the quality of mRNA was tested in sputum cell pellets.

Figure 1. Distributions of Inflammatory Cells in Healthy Humans and Patients With Asthma

Overall, progress was made toward our objectives, but practical problems arose, which limited our success in achieving the originally proposed results within the anticipated timeframe. The number of subjects that reliably participated was too limited and very few days in the rainy summer of 2000 met our "high" PM pollution day criteria. Only 2 days in the summer of 2000 met the "high" pollution day criteria, as opposed to an expected 18 days. Furthermore, only 50 percent of our previous subjects agreed to return for the study. Forty subjects were screened by the pulmonary function test (PFT) and clinical parameters. Twenty of these subjects failed screening on PFT criteria even after modification of exclusion criteria; 13 patients agreed to participate in the screening. These factors conspired to significantly reduce the number of sample days that could be collected.

The limitations in our ability to collect and analyze samples forced us to re-examine and to adjust our approach to achieve our planned objectives. We are analyzing the paired sputum and serum samples that we have collected from both normals and subjects with asthma to date, to assess those specific indicators that can be used successfully as asthma biomarkers. In particular, we propose to follow up on some recent animal studies by Dr. J. Zelikoff (NYU PM Center), which demonstrate that inhalation of concentrated ambient PM alters circulating immune blood cell profiles in a manner indicative of a stress response.

Based on the above discussed prior findings from the already collected samples, new subject blood samples were collected biweekly on 17 asthma subjects during the summer of 2001. This scheduled design avoided past problems experienced in trying to bring in subjects on short notice. Blood samples and PFT measurements were collected during subject visits over 12 weeks during July-September 2001 (total = six samples/subject). As shown in Figure 2, comparing two NY area PM2.5 sampling instruments, there was a wide range of PM2.5 levels experienced during the summer of 2001 in the New York area, with levels ranging from below 10 µg/m3 to nearly 60 µg/m3. This indicates that that a wide range of PM exposures were experienced by subjects during the course of the summer, providing a range of exposures with which to look for variations in biomarkers during this period. We also have analyzed daily PM samples collected near the NYU School of Medicine (at Hunter College) for trace elemental composition (using our PM Center Resource x-ray fluorescence analyzer), which will allow us also to examine our health effects data relative to exposures to various PM components over time.

Figure 2. PM2.5 Levels During the Summer in the New York Area

References:

Campbell JD, Stinson MJ, Simons FER, Rector ES, Hay Glass KT. In vivo stability of human chemokine and chemokine receptor. Human Immunology 2001;62(7):668-678.

Future Activities:

We will finish analyzing our serum plasma samples collected repeatedly over time for inflammatory cytokines and chemokines. Cytokines that have been shown can be meaningfully evaluated in these samples. Changes in immune cellular responses will be determined in both serum and sputum media; specifically, Eotaxin and IL-5 chemokines, IP-10 (a Th1 control), and IL-5. These markers recently have been shown to be measurable at very low levels in plasma (Campbell, et al., 2001). Moreover, if the effects upon neutrophil emigration in human subjects are found to be similar to those previously observed by Dr. Zelikoff in her separate animal model studies, additional endpoints will be examined in the sera, potentially including soluble TNF receptor and adhesion molecules. Genotype evaluations of all patients also are being conducted. Using these biomarkers and the other health data collected for each subject, we will look at comparisons of PM mass/component responders versus responders (i.e., comparing groups based on symptoms, peak flow, and cytokine data).

Journal Articles:

No journal articles submitted with this report: View all 4 publications for this subproject

Supplemental Keywords:

particulate matter, PM, exposure, epidemiology, clinical, toxicology, asthma, smoker, nonsmoker, sputum., RFA, Health, PHYSICAL ASPECTS, Scientific Discipline, Air, ENVIRONMENTAL MANAGEMENT, HUMAN HEALTH, particulate matter, Environmental Chemistry, Health Risk Assessment, Risk Assessments, Susceptibility/Sensitive Population/Genetic Susceptibility, Allergens/Asthma, Health Effects, Physical Processes, Environmental Monitoring, genetic susceptability, Atmosphere, Risk Assessment, ambient air quality, atmospheric particulate matter, particulates, asthma, asthma triggers, sensitive populations, air toxics, atmospheric particles, chemical characteristics, toxicology, ambient air monitoring, health risks, airborne particulate matter, ozone, asthma indices, environmental risks, exposure, second hand smoke, airway disease, airway inflammation, air pollution, aerosol composition, atmospheric aerosol particles, human exposure, airborne pollutants, inhalation, ozone monitoring, human susceptibility, allergic response, tobacco smoke, exposure assessment

Progress and Final Reports:

Original Abstract
  • 1999 Progress Report
  • 2000 Progress Report
  • 2002 Progress Report
  • 2003 Progress Report
  • 2004
  • Final Report

  • Main Center Abstract and Reports:

    R827351    EPA NYU PM Center: Health Risks of PM Components

    Subprojects under this Center: (EPA does not fund or establish subprojects; EPA awards and manages the overall grant for this center).
    R827351C001 Exposure Characterization Error
    R827351C002 X-ray CT-based Assessment of Variations in Human Airway Geometry: Implications for Evaluation of Particle Deposition and Dose to Different Populations
    R827351C003 Asthma Susceptibility to PM2.5
    R827351C004 Health Effects of Ambient Air PM in Controlled Human Exposures
    R827351C005 Physicochemical Parameters of Combustion Generated Atmospheres as Determinants of PM Toxicity
    R827351C006 Effects of Particle-Associated Irritants on the Cardiovascular System
    R827351C007 Role of PM-Associated Transition Metals in Exacerbating Infectious Pneumoniae in Exposed Rats
    R827351C008 Immunomodulation by PM: Role of Metal Composition and Pulmonary Phagocyte Iron Status
    R827351C009 Health Risks of Particulate Matter Components: Center Service Core
    R827351C010 Lung Hypoxia as Potential Mechanisms for PM-Induced Health Effects
    R827351C011 Urban PM2.5 Surface Chemistry and Interactions with Bronchoalveolar Lavage Fluid (BALF)
    R827351C012 Subchronic PM2.5 Exposure Study at the NYU PM Center
    R827351C013 Long Term Health Effects of Concentrated Ambient PM2.5
    R827351C014 PM Components and NYC Respiratory and Cardiovascular Morbidity
    R827351C015 Development of a Real-Time Monitoring System for Acidity and Soluble Components in Airborne Particulate Matter
    R827351C016 Automated Real-Time Ambient Fine PM Monitoring System