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.
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¡Ó0.8 vs. 7.1¡Ó0.7, 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. Read more here.
