Babies born to mothers who lost a substantial amount of weight after bariatric surgery have fewer cardiovascular risk factors than their siblings who were born before the surgery, a new study by researchers at Laval University has found.

This is because the metabolic changes and weight loss that occur after the surgery have a positive effect on inflammatory disease-related genes in the offspring, the researchers explained.

"Our research found that maternal obesity affects the genes of the offspring," said Dr. Frederic Guenard, 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.

"The good news is that we can do something to change this outcome: Reducing obesity in the mother has a positive health impact on the health of future offspring," he stated.

Bariatric surgeons and researchers at Laval University observed that children born after their mothers had a type of bariatric surgery called bilio-pancreatic bypass surgery were less likely to be obese, had improved insulin resistance, lower blood pressure and an improved cardiovascular disease risk profile.

This observation prompted Dr. Guenard and his team to study the underlying reasons for this improvement in heart disease risk.

They took blood samples from 25 children of 20 mothers who were born before their mothers had bilio-pancreatic bypass surgery and blood samples from 25 of their siblings who were born afterwards.

The children ranged in age from two to 24 years. The average body mass index (BMI) of the mothers was 45 before bariatric surgery and 27 after.

They then tested the DNA from blood samples, using a special tool the Infinium HumanMethylation450 BeadChip to find any changes in the genes caused by methylation.

They found that methylation levels were very different in the children born to mothers before bypass surgery from those who were born after.

Specifically, they found that more than 5,500 known genes with differential methylation in the children born before their mothers had bypass surgery compared to children born afterwards.

"Our findings show that maternal bariatric surgery results in significant metabolic effects to the methylation profiles of inflammatory disease-related genes," said Dr. Guenard.

"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.

"Basically, this study tells us that maternal obesity affects the obesity and cardiovascular risk profile of offspring and that weight loss can improve the cardiovascular health of children," he noted.
Dr. Guenard asserted that we would need other genetics studies to find out if weight loss changes the methylation profile of the genes of offspring of women who have lost weight through other measures.

The finding was presented at the Canadian Cardiovascular Congress, co-hosted by the Heart and Stroke Foundation and the Canadian Cardiovascular Society.