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PI: C. Nadziejko; Consultants: T. Gordon, L.C. Chen.
Our objective is to examine the effects of particle-associated
organic irritants on the cardiovascular system, an increasingly
important public health issue. The physical and/or chemical properties
of PM responsible for these serious health effects are currently
unknown. We will use blood pressure, heart rate, heart rate variability,
and selected coagulation parameters as endpoints to test the
hypothesis that the irritant properties of PM are responsible
for cardiovascular effects of PM inhalation of organic irritants
affects cardiovascular function, and the acute effects of smoke
are reflexively-mediated by stimulation of irritant receptors
in the respiratory tract. Little is known about the effects of
organic irritants that are absorbed onto particles. These knowledge
gaps will be addressed by exposing normal and compromised rats
to laboratory generated carbon particles coated with organic
irritants that are known to be constituents of PM. The rats will
be exposed to carbon particles coated with formaldehyde or acrolein
for 3 hrs, and physiological monitoring will be done before,
during, and up to 48 hrs after exposure. Air-exposed rats and
rats exposed to uncoated carbon particles will serve as controls.
Two sizes of particles will be examined, fine (0.3 µm,
at 150 µg/m3) and ultrafine (0.03 µm at
1 x 106 particles per cc). Normal rats and rats with
congestive heart failure (induced by ligation of the left coronary
artery) will be used. Cardiovascular parameters will be measured
in conscious animals using implanted transmitters. Blood will
be sampled for measurement of coagulation parameters. Respiratory
rate will be measured from fluctuations in blood pressure.
It is expected that each of the particle-associated organic
irritants examined will cause cardiovascular changes. The results of this
project will be directly compared with Dr. Chen´s research project
which will examine other chemical constituents of PM using the same animal
model and many of the same biological endpoints.
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