Study smoking in pregnancy changes genotype of the unborn baby

Smoking during pregnancy is even more dangerous than previously known
According to German researchers, smoking during pregnancy may be even more dangerous than previously known. Tobacco consumption can therefore influence the genetic material of the unborn child. Some of these injuries can lead to illness even in adulthood.

Smoking during pregnancy more dangerous than previously known
Health experts keep warning about the risks of cigarette smoking among pregnant women. Among other things, this significantly increases the risk of premature or miscarriage. In addition, smoking during pregnancy harms children for years, as scientific studies have shown. Thus, the offspring of smoking mothers has a significantly increased risk of cardiovascular disease. Apparently, the tobacco consumption of expectant mothers but even more dangerous than previously thought. As German researchers now report, mothers who smoke during pregnancy change the genetic material of their unborn child. This can lead to an increased risk of lung disease.

Smoking during pregnancy is even more dangerous than previously known. The genetic material of the unborn child can be changed. (Image: vadymvdrobot / fotolia.com)

Lifelong consequences for the offspring
A survey recently showed that thousands of women smoke despite being at risk during pregnancy. This can have lifelong consequences for their offspring. Scientists at the Helmholtz Center for Environmental Research (UFZ) in Leipzig and the German Cancer Research Center (DKFZ) in Heidelberg and the University of Heidelberg have found out that the use of tobacco by pregnant women can have a lasting effect on the epigenetic programming of the genome of the unborn child. These changes are not limited to individual DNA regions, but can be detected in the entire genome of children, as the researchers report in the journal "Molecular Systems Biology".

Increased risk of lung disease
"We were able to show for the first time that exposure to tobacco smoke also causes epigenetic changes in enhancers of gene regulation, so-called enhancers," said UFZ environmental immunologist Dr. med. Irina Lehman in a press release. It has long been known that environmental influences can alter the genome in the womb. In their latest study, researchers from Leipzig and Heidelberg have shown that epigenetic changes associated with tobacco smoke increase the risk to children of lung disease.

Negative influence by environmental factors
The data are from the epidemiological study LiNA (lifestyle and environmental factors and their influence on neonatal allergy risk). In the project, scientists are investigating which environmental factors can have a negative impact on children's health during pregnancy. "Our immune system reacts particularly sensitively to environmental pollution in the maturation phase before birth and in early childhood. Our research in the Department of Environmental Immunology (IMMU) therefore focuses on this sensitive window of opportunity, "reads the website of the UFZ.

Changes already in the womb
Since 2006, the Leipzig scientists have been accompanying 622 mothers and their children. The pregnant women were examined intensively for environmental pollution, later the health of the children was carefully analyzed. In the current study, pregnant women from smoking and non-smoking families were compared. "We were able to demonstrate the epigenetic changes in the smoking mothers as well as in the umbilical cord blood of newborn children," says Lehmann. Thus, the changes occur in the womb and affect the gene regulation of the unborn child. Even several years after the birth of the negative influence in the children could be detected. However, according to the researchers, this may have been due to the fact that most children continued to be exposed to tobacco smoke. "Children who are already burdened with tobacco smoke before birth are usually also after birth," said Lehmann.

Dysregulation of multiple genes
Researchers have found that smoking often affects so-called enhancer regions in the genome. These are DNA segments that activate one or more genes at specific times. "When an enhancer region is affected by the effects of smoking, it can lead to a misregulation of several genes," Lehmann explained. The researchers show in their work an example of the consequences of a dysregulated enhancer: The enzyme JNK2 (c-Jun N-terminal protein kinase 2) is involved in the development of inflammatory reactions. Influencing the enhancer that activates JNK2 may increase the risk of lung disease in children later in life.

Starting points for new therapy options
That the lifestyle of the parents burdened the genes, have already shown other studies. In their current analysis, German scientists have now identified over 400 enhancers affected by tobacco smoke. These regulate genes that play a role in diabetes, obesity, or even cancer. "Through this discovery, we now begin to understand the mechanisms that cause smoking to lead to such diverse diseases," said Roland Eils of the DKFZ. As the scientists said, the findings of this work should provide starting points for new treatment options for environmental diseases. "The better we understand what is being misdirected by the environmental impact, the better we can respond to it. In the case of tobacco smoke, however, avoiding exposure is still the best option, "said Lehmann. (Ad)