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EMBARGOED FOR RELEASE UNTIL
MAY 1, 2007
APS Contact
Donna Krupa
Office: (301) 634-7209
Cell: (703) 967-2751
dkrupa@the-aps.org
Newsroom Opens at 12:00 p.m.
Saturday April 28
APS Newsroom
East Registration Area
Washington Convention Center
APS Press Room: (202) 249-4174
Post-Menopausal Females, The Elderly And Males Most
Heavily Impacted
By A Chemical Component Of Diesel Exhaust Particles
Estrogen appears to provide protective effects in
animal model
WASHINGTON – A new study finds that exposure to
a chemical component of diesel exhaust particles can compromise the ability
of resistance arteries to regulate blood flow to bone marrow.
Post-menopausal females, the elderly and males are most likely to be
impacted, according to a new vascular biology study– using an animal model –
being presented at the 120th Annual Meeting of The American
Physiological Society (APS;
www.The-APS.org) from April 28-May 2, 2007 in Washington, DC.
The study, Effects of Age, Gender, and Estrogen on
Endothelium-Dependent Vasodilation Subsequent to Phenanthraquinone Exposure,
was conducted by Rhonda D. Prisby, Judy Muller-Delp and Timothy R.
Nurkiewicz, all of the Center for Interdisciplinary Research in
Cardiovascular Sciences at the West Virginia University School of Medicine
in Morgantown, WV, USA. Dr. Nurkiewicz is presenting the findings on behalf
of the University’s interdisciplinary cardiovascular research team. The
research was funded by the Health Effects Institute and the National
Institutes of Health.
Background
Diesel exhaust contributes significantly to the U.S.
ambient air pollution burden. This form of air pollution is the product of
diesel fuel combustion, commonly generated by buses, trucks, trains and
ferries. The particles can remain airborne for extended time periods, and
travel long distances prior to being inhaled. When inhaled, chemical
components such as polyaromatic hydrocarbons (PAH) attached to the particles
can interact with the body. Quinones are PAHs and are among the more toxic
components of diesel exhaust. In the current study, the investigators used
phenanthraquinone (PQ) because previous research found PQ to compromise the
ability of larger blood vessels to relax. They have also noted that in
certain populations, exposure to particle pollution may exacerbate various
cardiovascular diseases.
The principal nutrient artery (PNA) is the major
resistance vessel that regulates blood blow to the femoral bone marrow. The
ability of arteries to dilate (widen) declines with age and this corresponds
with reduced blood flow in an artery’s target organ. Impaired blood flow
regulation in the bone marrow can have wide- and long-reaching health
consequences. It is unclear what PQ does to the ability of this artery to
dilate, and how age or gender alters any such effect.
Summary of Methodology
Against this backdrop the research team sought to
determine whether PQ impairs vasodilation in the PNA and identify whether
age, gender or estrogen alters the presumed effects of PQ. The researchers
isolated and cannulated femoral PNAs from intact and ovariectomized (OVX)
female rats (6, 14 and 24 months) and male rats (6 and 24 months). To
evaluate the ability of the PNA to dilate when it was incubated with PQ,
researchers used the chemical acetylcholine (ACh).
A series of ACh doses were administered over time, starting with low doses
and graduating to higher doses to produce maximum dilation of the artery
Results
The researchers found that:
-
exposure to PQ had greatly compromised – by approximately
65 percent – the ability of the blood vessels to effectively dilate in
six month old male rats, but had no effect in female rats;
-
at 14 months (female rats) and 24 months (female and male
rats), PQ had impaired and abolished vasodilatation, respectively;
-
in all OVX rats (i.e., the young females who had lost
estrogen due to menopausal status), PQ abolished vasodilatation;
-
following the loss of estrogen, particularly at six months
where a cardioprotective effect was previously observed, PQ exposure had
obliterated vasodilation.
Conclusion
This study demonstrates that exposure to the diesel
particle component PQ, can compromise the ability of the PNA to regulate
bone marrow blood flow in males, the elderly and post-menopausal females in
an animal model. These findings may provide an important link to other
discoveries involving the protective effects of estrogen to environmental
pollutants.
***
The
American Physiological Society (APS) has been an integral part of the
scientific discovery process since it was established in 1887. Physiology
is the study of how molecules, cells, tissues and organs function to create
health or disease.
# # #
NOTE TO EDITORS: The APS annual meeting is part
of the Experimental Biology 2007 (EB ’07) gathering and will be held April
28-May 2, 2007 at the Washington, DC Convention Center. To schedule an
interview with a member of the research team, please contact Donna Krupa at
301.634.7209 (direct dial), 703.967.2751 (cell) or
DKrupa@the-APS.org.
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