Adult heart disease linked to womb

Restrictions in blood flow to a foetus cause damage said to be linked to the development of heart disease in adults.

Otago University researchers have shown the damage occurs in experiments on rats, and they say it has important implications for humans.

"This study supports the hypothesis that links the in-utero environment to cardiovascular disease later in life," they told the Medical Sciences Congress in Queenstown.

They found that the "moderate insult" of artificially restricting blood flow to the uterus of some rats - mimicking high maternal blood pressure - led to small offspring.

It could also permanently alter the pups' blood vessels by lifting the number of defects in elastic tissue.

Elastic tissue gives blood vessels their flexibility. It is thought the body stops making elastin, the protein that leads to elastic tissue, in childhood.

Some researchers believe elastic tissue defects initiate the build-up of plaques on heart arteries, linked to heart attacks.

"That's controversial and the mechanism is unknown," said Professor Kent Thornburg, a world leader in research on the foetal origins of cardiovascular disease in adults.

But the Otago research might help to explain why blood vessels in the arms and legs stiffened with age, making it harder to pump blood through, said Professor Thornburg, of Oregon Health Sciences University in the United States.

He explained to the conference research findings that show connections between a less than optimum foetal environment - especially malnourishment, maternal stress or low oxygen levels - and adult heart disease.

"Under-growth, or being born small, is highly correlated with the risk of having coronary heart disease prematurely as an adult," he said.

Heart development was most sensitive to malnourishment in early and late gestation and at times during early infancy.

He showed how higher levels of foetal blood flow resistance led to the too-early maturing of heart muscle cells, leaving them unable to divide.

That meant a greater likelihood of having fewer heart cells which then required the heart to work harder. It might also make the heart more prone to failure.

Professor Thornburg said in the first weeks after conception, when the heart was only 1mm across, the way in which blood flowed through it influenced the genes that set the number of heart cells.

Professor Jane Harding, of Auckland University's Liggins Institute, said it was widely accepted that disturbed foetal growth was associated with diseases including heart disease, stroke and type 2 diabetes.