Grantee Research Project Results
2005 Progress Report: Air Pollutants: Cardiovascular Effects and Mechanisms
EPA Grant Number: R831918Title: Air Pollutants: Cardiovascular Effects and Mechanisms
Investigators: Bonham, Ann
Institution: University of California - Davis
EPA Project Officer: Chung, Serena
Project Period: August 1, 2004 through July 31, 2008 (Extended to July 31, 2009)
Project Period Covered by this Report: August 1, 2004 through July 31, 2005
Project Amount: $1,510,000
RFA: The Role of Air Pollutants in Cardiovascular Disease (2003) RFA Text | Recipients Lists
Research Category: Airborne Particulate Matter Health Effects , Air
Objective:
The objective of this research project is to resolve the underlying mechanism(s) mediating the airborne particulate matter exposure-induced reduced heart rate variability (HRV) in an animal model using environmentally relevant “real world” particulate pollutants.
Progress Summary:
After testing several models, we have constructed a prototype insert for holding individual mice in the exposure chamber for this study. The system houses eight mice per chamber. A total of eight identical chambers were constructed, four for sham exposure and four for concentrated ambient particles (CAPs) exposure. A total of 31 mice were randomly assigned to the sham exposure group and 31 to CAPs exposure for the first winter season. The mice were acclimated to the exposure chamber 1 week prior to the exposure and randomly rotated through the sub-compartment of the chamber to avoid any potential positional effects and to reduce the stress associated with changes in environment. Eighteen mice from each group were implanted with an ECG telemetry system at least 2 weeks prior to the exposure protocol. After 3 days of CAPs exposure or sham control, 24-hour ECG signals were recorded for HRV analysis. Currently, we are analyzing these data. An additional 13 mice were used for pulmonary tests. These samples also are under analysis. Blood plasma, brain, and heart tissues were collected for analysis of inflammatory mediators and protein expression.
There was a technical difficulty in performing the exercise stress tests on all 36 mice on the second day after exposure period. We have adapted another stress test (restraint test) to replace the exercise stress tests. The restraint test has been shown to alter autonomic regulation of the HRV. The mice were placed in individual restrainers in their home case for 2 hours. The ECG signals were continuously recorded 4 hours before, during, and 6 hours after the test. In addition, we have collected blood plasma samples from these animals for measurement of circulating cytokines and harvested brain and heart tissues for protein analysis.
Future Activities:
We will: (1) continue with exposures in the summer season; (2) expose aged mice; (3) analyze the HRV, particle concentration and composition, and stress test results; and (3) conduct patch-clamping analysis of identified cardiac vagal neurons.
Journal Articles:
No journal articles submitted with this report: View all 13 publications for this projectSupplemental Keywords:
air pollutants, heart rate variability, electrophysiology,, Health, RFA, Scientific Discipline, Air, Health Risk Assessment, Risk Assessments, particulate matter, Environmental Chemistry, Biochemistry, Toxicology, ambient aerosol, lung disease, long term exposure, airborne particulate matter, cardiovascular vulnerability, ambient particle health effects, acute cardiovascular effects, cardiovascular disease, lung injuryProgress and Final Reports:
Original AbstractThe perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.