Tuesday, 29 April 2008

Heart disease related gene identified

Researchers from Imperial College London, the Medical Research Council (MRC), and other international institutions have identified a gene that can cause the heart to become enlarged, greatly increasing the risk of heart attacks and heart failure.
The findings are based on a study that revealed how a gene called osteoglycin (Ogn), which had not previously been linked with heart function, plays a significant role in regulating heart growth.

According to the study, the gene can behave abnormally in some people, and that this can cause the heart becoming abnormally enlarged.

The researchers hope that with a complete understanding of how enlarged hearts are linked to the workings of genes like Ogn, they will be able to develop new treatments for the condition, which affects a large proportion of those with high blood pressure, obesity and diabetes.

They hope that their findings will provide new avenues for treating people who either have an enlarged heart or are at risk of developing one, which can only be treated by lowering blood pressure currently.

In the study, researchers demonstrated that Ogn regulates the growth of the heart's main pumping chamber, its left ventricle.

If the left ventricle thickens, this creates a condition known as elevated Left Ventricular Mass (LVM), a major contributing factor for common heart diseases.

When the heart is enlarged it needs more oxygen and becomes stiff. This can cause shortness of breath or lead to a heart attack.

In the study, the researchers found that higher than normal levels of Ogn were linked to the heart becoming enlarged in rats and mice and in humans.

For the study, the researchers first associated the Ogn gene with elevated LVM by looking at rat models and analysing how LVM related to the genetic makeup of rats with both elevated and normal LVM.

Then, they conducted the same analyses on samples from the human heart, volunteered by patients who had undergone cardiac surgery.

Researchers found that out of 22,000 possible genes, Ogn was the gene most strongly correlated with elevated LVM in humans.

"We already knew that enlarged hearts were linked with conditions such as high blood pressure and obesity but figuring out the genetic causes as well could be key to working out how to treat the condition," Nature quoted Professor Tim Aitman, co-author of the study from the MRC Clinical Sciences Centre and Imperial College London, as saying.

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