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EMBARGOED FOR RELEASE UNTIL
MAY 1, 2007, 12:01 AM
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
Prenatal Nicotine Exposure Can Lead To Cardiac Function
Reprogramming In Adult Offspring
Female
offspring more likely to be impacted than males, lab study finds
WASHINGTON
– At least 11 percent of American women smoke during pregnancy. The
negative effects of nicotine exposure to their fetuses and newborns are
significant. A 2004 report by the Surgeon General, for example, found that
women who smoked during pregnancy had children who were at a three times
higher risk for SIDS than were the offspring of non-smokers. Now, a new
study using laboratory rats, provides strong evidence that the effects of
maternal smoking during the prenatal period of life can lead to cardiac
vascular dysfunction beyond the formative years -- and into adulthood.
The finding is part of a new
study entitled Effect of Prenatal Nicotine Exposure on Coronary Flow in
Adult Offspring: A Gender Dichotomy. It was conducted by Daliao Xiao,
Jennifer Lawrence, Shumei Yang, and Lubo Zhang, all of the Center for
Perinatal Biology, Loma Linda University, School of Medicine, Loma Linda,
and the Department of Chemistry and Biochemistry, California State
University, San Bernardino, CA Dr. Zhang will lead a discussion of
the findings at the 120th annual meeting of the American
Physiological Society (APS;
www.the-APS.org), being held as part of the Experimental Biology (EB
’07) meeting. More than 12,000 scientists and researchers are attending the
conference, being held April 28-May 2, 2007 at the Washington, DC Convention
Center.
Summary of Methodology
Nicotine (2.1 mg/d) was
administered via osmotic minipumps placed under the skin throughout
gestation and up to ten days after delivery. Hearts were isolated from three
month old male and female offspring, and subjected to 25-minutes of
mechanical obstruction of blood flow ischemia followed by 60-minutes of
myocardial impairment caused by opening of the blockage. Pulmonary artery
discharge was collected as an index of coronary flow (ml/min/g heart wet
weight).
Summary of Results
The researchers found:
-
that nicotine significantly decreased coronary flow in
female (10.4±0.8 vs. 7.1±0.7, P< 0.05) but not in male (9.1± 0.5 vs.
9.0±0.7, P>0.05) hearts at baseline;
-
nicotine treatment significantly decreased coronary flow
during reperfusion up to 60-minutes in female, but not in male, hearts.
-
prenatal nicotine exposure significantly increased
ischemia and reperfusion-induced infarct size in left ventricles and
significantly affected post-ischemic recovery of left ventricular
function in both male and female offspring. However, the effect of
nicotine was significantly more pronounced in females than in males.
Conclusions
The results suggest that
prenatal nicotine exposure selectively decreases coronary flow in adult
female offspring. The findings suggest that prenatal nicotine
exposure causes a reprogramming of cardiac function resulting in an increase
in heart susceptibility to ischemia and reperfusion injury in adult
offspring. In addition, the effect of nicotine shows a gender dichotomy with
females being more susceptible than males.
The selective effect of
nicotine on coronary flow in the female heart may contribute to the
increased susceptibility of female vs. male hearts, in response to ischemia
and reperfusion-induced cardiac damage in animals exposed to prenatal
nicotine treatment. Additional study is thus required.
***
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 Dr. Zhang or another member of the research team,
please contact Donna Krupa in the newsroom at 202.249.4174, 301.634.7209
(direct dial), 703.967.2751 (cell) or
DKrupa@the-APS.org.
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