Scientists at the University of Southampton in the UK, have made a discovery that improves our understanding of how arteries control blood pressure. The finding is expected to lead to better treatments for cardiovascular or heart disease.

Led by Dr Graham Burdge, Reader in Human Nutrition at Southampton, the scientists report their study in the 3 April issue of PLoS ONE. The research was funded by the British Heart Foundation (BHF), and BHF Professor Mark Hanson is one of the co-authors.

High blood pressure is a risk factor in developing heart disease, a growing public health issue that was responsible for one in three deaths in the UK in 2009.

Burdge told the press:

“Discovering a new process which controls how arteries work, and finding that it can be modified in the laboratory, raises a strong possibility for developing new medicines that may lead to better ways of treating cardiovascular disease.”

Arteries control blood pressure by balancing two processes: one that constricts the artery wall and another that relaxes it.

But in people at risk of developing high blood pressure or atherosclerosis, there is more constriction, impeding the free flow of blood, which increases the risk for heart attack and stroke.

The process through which arteries constrict their muscle walls relies on molecules called eicosanoids. These fat-like compounds are made with the help of enzymes that break down polyunsaturated fats.

By studying what happens in rats, the team discovered that the polyunsaturated fats used to make the eicosanoids are made by muscle cells in the arteries, and not taken from blood, as previously thought.

They experimented with deactivating two enzymes that help make the polyunsaturated fats. They found this reduced arterial constriction, leading to freer blood flow, thereby lowering the risk for high blood pressure.

They also found “epigenetic switches” behind this process that may explain why some arteries show early signs of causing high blood pressure.

One switch controls a key gene for making polyunsaturated fats, while another switch over-compensates for this.

Epigenetics is the study of how changes in gene activity that do not change genetic code still get passed on to the next generation. It has led to the concept of the “epigenome”, an additional layer of instructions in the cellular material that controls gene expression. Put very crudely, it is as though the genome in DNA contains all the instructions for making an individual, but the epigenome decides which instructions are obeyed.

Epigenetic influences start early in life, even before birth. The discoveries made in this study, for instance, show that the amount and type of fat that the mother consumes in pregnancy affects the future heart health of her offspring by changing the ability of their arteries to control blood pressure.

Hanson said their findings add to the “substantial body of knowledge showing that a pregnant mother’s diet can have significant effects on the health of her children in later life.”

“However, pregnant women shouldn’t be too worried – by eating a healthy, balanced diet mums can help protect their own and their child’s heart health in the future,” he added.

Burdge said a test based on epigenetic changes could provide a new way of screening people for risk of heart disease before symptoms develop, something we can’t do at present.

In time, it might also be possible to correct such epigenetic defects, he added.

Written by Catharine Paddock PhD