Maternal Smoking Can Change the Development of Children’s LungsMay 2, 2014
When a child is growing in the mother’s womb, it’s extremely vulnerable. Everything a mother does, from the air she breathes to how she manages stress can affect the development of organs and susceptibility to disease. In the case of smoking, it can actually change the physical make up of the lungs making it more likely the child will have lung related problems that might not even show up until years later. Lisa Joss-Moore, Ph.D. and associate professor in the Division of Neonatology, talks about how a mother’s smoking while pregnant is more damaging to a baby’s development than you might have thought and about her research to understand what causes these changes in an effort to treat them.
Interviewer: I think we've all realized that smoking while you're pregnant is bad for your baby, but it could be worse than you thought. We'll examine that next on The Scope.
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Interviewer: When a child's in the womb, it's very sensitive to the environment it's subjected to, and the consequences of that environment can really have a long-term effect for the baby afterwards. That's according to new research from Lisa Joss-Moore. She's a PhD. and also an associate professor in the Division of Neonatology at the University of Utah. Tell me about your research and what you found out.
Dr. Joss-Moore: Well, we're interested in how early life events, like maternal tobacco smoke, can have a life-long influence on the development of disease. What we do in our lab is we look at early insults, for example, maternal tobacco smoke. What we do is we have an animal model where we introduce tobacco smoke just like it would be if it were a pregnant woman smoking. We give the same amount of tobacco smoke that you would see in an active smoker, and we only give that tobacco smoke exposure during the fetal period.
During the post-natal period, there's no further exposure, and what happens in the long-term is that the model animal developed Type 2 diabetes, obesity, insulin resistance, and various kinds of lung deficiencies. What we're focusing on in this particular study is the effect of prenatal smoke exposure on the development of lung disease. So this is like if you were a human baby, this means that your mom smoked while she was pregnant, but then you had no other exposures after you were born. What's very interesting and somewhat disturbing is that we have shown that if you have that early exposure, you can grow up to develop insulin resistance, Type 2 diabetes, obesity, and changes in your lung structure and function.
Interviewer: Wow. So it goes way beyond just lungs?
Dr. Joss-Moore: It goes way beyond just lungs.
Dr. Joss-Moore: We focus on the lung and the other aspects in our lab. One of the things that we have learned about the lung, which was previously characterized mildly, but we're studying to understand the mechanisms now is that when you have these fetal exposure to tobacco smoke, your lung changes in terms of its molecular composition. It changes in terms of its structure, and mostly importantly, it changes in terms of its function.
Interviewer: So it's a different lung than somebody that hasn't been exposed?
Dr. Joss-Moore: Correct.
Dr. Joss-Moore: Correct. And while these studies are ongoing, we expect that this new lung, this different lung, is actually much more sensitive to damage from subsequent insults, such as a Salt Lake inversion or exposure to tobacco smoke. Should that individual grow up to become a smoker themselves, their lungs are going to be much at risk of damage than had they have never had the in-utero exposure.
Interviewer: Is that because the fetus is still developing, and it's somehow changing the way that genes are doing what the genes do?
Dr. Joss-Moore: That's exactly what we found. We looked at various pathways. One of the pathways that we're particularly fond of involves signaling from fatty acids, particularly omega-3 fatty acids. The downstream targets of some of those signaling includes epigenetic modifying molecules, and what happens when you mess up those epigenetic pathways, you change the gene expression program. When you change gene expression in an organ that's developing, the result is that you develop a slightly different organ than you would've had otherwise.
Interviewer: So the analogy would be that your genes are these little machines that are manufacturing the parts, and if something isn't manufactured properly, you get a part that's not what you expect?
Dr. Joss-Moore: Exactly. If you live in an extraordinarily clean environment, and you have no other insults on your lungs, maybe you get to be an old person before you notice. Sadly, that's not the case. We have a lot of other lung irritants that we're exposed to, and we expect that what you would see is a more rapid onset of damage. There are studies that link early tobacco and nicotine exposure to the development of asthma, hypersensitivity of the airways, and other lung disorders.
What we're trying to do in my lab is really trying to understand some of the mechanisms by which this early exposure produces these changes. We want to understand the mechanisms because once we do we can really begin to develop targeted interventions that may make a difference.
Interviewer: Gotcha. And understanding, too, that it would mean that you would hurt something else when you're trying to . . .
Dr. Joss-Moore: Exactly. Because the population that we're really looking at is newborn infants, there's a lot of development going on. While we may have something that's really good for the lungs, it might mess up the kidneys, for example. So one of the reasons why we focus on what we do in an animal model is that it gives us the ability to use our intervention, and one of our interventions involves an omega-3 fatty acid DHA. We can look at the effect on the organ that we care about in this case, which is the lung, but at the same time we could look at other organs, such as the brain and the kidney, and we can make sure that our treatment that's helping the lung is not hurting any of those other organs.
Interviewer: Yeah. So what's the big take-away from this research for the average person?
Dr. Joss-Moore: Well, the first thing is that it's very important to realize that these early life exposures really do have long-term effects on the fetus.
Interviewer: Would you describe them as profound?
Dr. Joss-Moore: Yes. Absolutely. There's a big body of evidence now that's really identified that. The general field is known as the developmental origins of health and disease, and the idea that if you have toxic insults, like, for example, tobacco smoke, there's other maternal conditions such as hypertension that can really change the way a fetus develops. Some of those consequences in the fetus may not be felt until later on in life. But if we can understand what's causing them, it's going to allow us to intervene and perhaps prevent some of those diseases from developing later on.
Interviewer: So could you actually make a lung that wasn't made properly the first time right, years after the fact?
Dr. Joss-Moore: Well, I don't know about years, but we know that we can correct a number of the molecular, structural, and functional findings that we found. So that's very exciting for us to continue down that path and see how long those effects remain in place. We're hoping that they're permanent.
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