The Effects of Exposure to Concentrated Ambient Air Particles on Human Blood Clotting, Coagulation, and Heart Rate VariabilityEPA Grant Number: U915825
Title: The Effects of Exposure to Concentrated Ambient Air Particles on Human Blood Clotting, Coagulation, and Heart Rate Variability
Investigators: Hall, Aron J.
Institution: University of North Carolina at Chapel Hill
EPA Project Officer: Edwards, Jason
Project Period: September 1, 2000 through June 1, 2001
Project Amount: $25,538
RFA: STAR Graduate Fellowships (2000) RFA Text | Recipients Lists
Research Category: Academic Fellowships , Air Quality and Air Toxics , Fellowship - Air Pollution
The overall objective of this research project is to evaluate and characterize the physiological response of human subjects following their exposure to concentrated fine particles. The specific objectives are to: (1) determine whether people exposed to fine particles show evidence of acute phase reactions, specifically blood clotting and/or coagulation as evaluated by blood protein indices; (2) determine whether geriatric people exposed to fine particles show changes in autonomic nervous system function as evaluated with heart rate variability; and (3) determine whether exposure to fine particles elicits different responses in healthy, young people versus healthy, geriatric people.
To test the stated hypotheses, the study involved exposing human subjects to concentrated ambient particles, and assessing the effects of this exposure on blood clotting and coagulation indices. The 30 subjects included in the study were examined as two distinct subgroups for the purposes of comparing susceptible subpopulations. Twenty young, healthy individuals (18-40 years old) were randomized to either exposure to air (n = 15) or concentrated ambient particles (n = 15). Ten geriatric, healthy individuals (over 65 years old) each had two exposures; one to air and the other to concentrated ambient particles. The particle concentrator increased the burden of fine particulate matter (0.1 to 2.5 mm in diameter) to concentrations approximately 6- to 8-times greater than those levels found in the ambient Chapel Hill air, although there is significant daily variability in ambient fine particle concentrations. Blood was drawn before exposure, immediately after exposure, and 24 hours after exposure to assess the changes in acute phase reactants. Blood indices assessed include proteins and protein cofactors along the coagulation and clotting pathways; specifically fibrinogen, C reactive protein, D-Dimer, and von Willebrand factor. Other blood endpoints assessed include albumin, total protein, lactate dehydrogenase (LDH), white blood cell count, red blood cell count, hematocrit, platelets, polymorphonuclear leukocytes (PMNs), lymphocytes, monocytes, and eosinophils. Heart rate variability changes also were assessed in geriatric subjects using a Holter monitor.