Investigators have found that babies born to obese mothers who lost weight after bariatric surgery have less cardiovascular risk factors compared to siblings born before the surgery.
The bodily changes and weight loss that occur as a result of the surgery, positively effect inflammatory disease-related genes in the offspring, according to new research presented at the Canadian Cardiovascular Congress, co-hosted by the Heart and Stroke Foundation and the Canadian Cardiovascular Society.
The authors found that maternal obesity affects the genes of the offspring. Therefore, these characteristics can be changed to better impact the child. Eliminating obesity in the mother can lead to a favorable health outcome for the offspring.
This study focused on epigenetics, how our genes turn on and off by environmental factors. The new part of this study is the fact that scientists explored how these changes can influence the DNA of our children, without having to alter the DNA sequence.
Originally, it was thought that DNA structure caused genetic variation. However, now we know that genes can be expressed, and several processes can influence them to turn on or off.
One of these processes causes small molecules to bind to DNA. These molecules are made by one’s own body and their binding to DNA is regulated by the environment (from food or toxins).
Molecules called methyl groups are responsible for turning genes on and off, a process known as DNA methylation. This process alters the gene expression but does not change the gene sequence. Normally, more methylation means a gene is turned off and less means it is turned on.
Maternal obesity can lead to significant pediatric obesity through genetic, environmental and epigenetic influences. Obesity while pregnant increases the likelihood of the offspring to develop lifelong weight problems and increases risk of heart disease.
Bariatric surgeons and researchers at Laval University have discovered that children born after their mother had weight loss surgery, called bilio-pancreatic bypass surgery, were less likely to be obese, had better insulin resistance, lower blood pressure, and a decrease in risk for cardiovascular disease.
Dr. Frédéric Guénard, a post-doctoral fellow under the supervision of Dr. Marie-Claude Vohl of the Functional Food Institute at Laval University and a recipient of a Heart and Stroke Foundation Research Fellowship, and his team of researchers decided to investigate as to why there is an improvement in heart disease risk.
They took blood samples from 25 children of 20 mothers who were born before their mothers underwent the bilio-pancreatic bypass surgery, and blood samples from 25 of their siblings who were born after the surgery.
The children ranged in age from 2 to 24 years. The average BMI of the mothers was 45 before weight loss surgery and 27 after. Bariatric surgery is recommended for people with a BMI of 40 or greater, or a BMI of 35 or greater combined with conditions such as diabetes and are of low surgical risk.
DNA from the blood samples was tested using the Infinium HumanMethylation450 BeadChip to identify any alterations in the genes caused by methylation.
The researchers found that the methylation levels were extremely different in the children born to mothers before bypass surgery from those who were born after.
Particularly, the authors found that more than 5,500 known genes with differential methylation in the babies born before their mothers underwent surgery compared to children born after the surgery.
Dr. Guénard says:
“Our findings show that maternal bariatric surgery results in significant metabolic effects to the methylation profiles of inflammatory disease-related genes. The bariatric surgery and weight loss experienced by the mothers created an in utero environment that favorably changed the gene methylation levels of the fetus.”
In simple words, this study shows that maternal obesity affects the weight and cardiovascular risk of children. Therefore, weight loss can better the cardiovascular health of children.
Heart and Stroke Foundation spokesperson Dr. Beth Abramson explains:
“We know our genetic makeup influences our children’s risks, but so can our environment. For example, if a disease runs in a family, we know to watch out for it in the children as they age. This study shows that external factors also influence our risk for heart disease, and that of our offspring by switching genes on or off in our DNA; providing a glimpse as to why this occurs. This is why lifestyle behaviors are so important.”
Dr. Abramson and Dr. Guénard both say this study verifies how important it is to maintain a healthy weight during all stages of life. More genetics studies are recommended to examine if weight loss can change the methylation profile of the genes of children of mothers who have lost weight by other means.
Written by Kelly Fitzgerald