Cigarette Smoke Could Alter Shape of Heart
[Writer] This is research news from U-I-C – the University of Illinois at Chicago.
Today Mariann Piano, professor of biobehavioral health science in the College of Nursing, talks about how prolonged exposure to cigarette smoke can increase levels of the stress hormone norepinephrine and enzymes in the heart that have the potential to reshape the left ventricle.
Here’s Professor Piano:
[Piano] We recently completed a study where by we examined the effects of five weeks of cigarette smoke on the myocardium, or the heart muscle.
In order to do this we used an animal model of cigarette smoke exposure. The animals were exposed to cigarette smoke twice a day for about 45 minutes. And just to give people an idea in terms of what level of smoke exposure that is, this level equates into what is similar to a moderate smoker – that is, someone smoking about 10-12 cigarettes a day.
What we found was that only after five weeks of smoking, that the heart began to show signs of enlargement and what is also called remodeling. So essentially the size and the shape of the heart were modified by this five weeks of cigarette smoking.
We also found – a major finding – was that this level of smoke exposure was also associated with the activation of enzymes, which are referred to as mitogen-activated protein kinases, that are important in regulating different types of cellular functions within the heart muscle, as well as cell growth, differentiation in cell death.
So our results suggest that activation of these enzymes may be very important in mediating the adverse or very negative effects of cigarette smoke on the heart.
Another major finding was that this level of cigarette smoke exposure was also associated with very large increases in the stress hormone, norepinephrine. And when norepinephrine is elevated, which it is in short periods of stress, it’s elevated and then the levels go back down. That is typically beneficial or adaptive. However, if norepinephrine levels are maintained high and for a period of time, norepinephrine can also initiate a lot of adverse effects on the heart muscle.
People ask where are we going next? We conducted these experiments in an adult animal model. We’re really hoping now to extend or to begin experiments in adolescent animals to determine if, perhaps, the adolescent myocardium, or heart, is more vulnerable to the effects of cigarette smoke.
So we’re hypothesizing that perhaps we’ll see some of these cardiac changes earlier and they’ll be more profound in the adolescent heart.
Ultimately, down the road, we would like to translate these findings such that we’d be looking at the effects of cigarette smoke in young adolescents, in college students who are smoking.
And I also want to mention another important aspect of the project that we are currently engaged in: also looking at the effects of the combination of cigarette smoking and binge drinking. Another really important aspect of my laboratory work is to investigate the cardiovascular consequences of binge drinking. So studies are ongoing in that area as well.
[Writer] Mariann Piano is a professor of biobehavioral health science in the College of Nursing.
For more information about this research, go to www-dot-news-dot- uic-dot-edu (www.today.uic.edu) … click on “news releases.” … and look for the release dated November 13, 2008.
This has been research news from U-I-C – the University of Illinois at Chicago.
