Key enzyme is 'promising'

New developments in heart disease research, including a drug that could prevent blood clots and a therapy for treating blocked…

New developments in heart disease research, including a drug that could prevent blood clots and a therapy for treating blocked arteries, are being developed under two innovative programmes funded by the Research Health Board (RHB).

Scientists at the Regenerative Medicine Institute in NUI Galway have developed a therapy that could prevent blockages of the arteries reforming after patients undergo a bypass operation or have a wire stent inserted.

Although both techniques have been used with considerable success to unblock arteries, arteries can, however, be restored to a healthier state using gene therapy to deliver a key enzyme, according to Prof Tim O'Brien who leads the research in NUI Galway after leaving the US Mayo Clinic.

This "key enzyme" enables cells to manufacture a small gas molecule called nitric oxide (NO) which plays a role in regulating blood flow and has been a target for many other drugs.

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Significantly, there is less nitric oxide in blocked arteries than in healthy blood vessels according to O'Brien. "We use a crippled version of the common cold virus to deliver the gene for a nitric oxide enzyme," he explains.

In tests completed on laboratory animals, nitric oxide levels rose and the channel in the animals' arteries became less narrow.

"This looks really promising. Especially as the enzyme we chose also promotes healing of the blood vessel.

"It could be a really useful technique with a stent or bypass," he says.

However, it will be some years before the research moves onto human trials.

UCD Prof Therese Kinsella warns, however, that researchers testing possible new drugs should test them on human cells and tissue, and not just on laboratory animals.

Separately, at the Royal College of Surgeons in Ireland (RCSI), researchers have identified a molecule that can prevent unwanted clots forming which can cause a stroke. Prof Niamh Moran hopes the molecule could be the basis of a new drug for people at risk of a thrombosis.

The Irish Heart Foundation contends that cardiovascular disease is Ireland's biggest killer, accounting for around one-third of all deaths in Ireland every year. The two main causes of the condition are coronary heart disease or blocked arteries and stroke caused by a clot.