Scientists are preparing to infect heart disease patients with genetically engineered viruses. The modified microbes would kickstart the patients' hearts into manufacturing life-saving proteins and so restore their health, say the researchers.

The project is part of an ambitious programme aimed at countering coronary disease, now sweeping Britain. In the past 10 years, hospital admissions of patients with serious heart impairment have risen by 50 per cent. It is now the leading cause of death in the country.

Several onslaughts have been launched in a concerted bid to tackle the disease, including a major programme based in Glasgow, a city afflicted with the nation's worst cardiac statistics.

'Most coronary research has concentrated on prevention, on changing people's lifestyles so they reduce their risk of getting heart disease,' said Professor Godfrey Smith, of Glasgow University's Institute of Biomedical and Life Science. 'By contrast, we are trying to put things right after heart disease sets in, and to do that we plan to exploit genetically modified viruses.'

Scientists have found that as heart disease begins to affect a person, arteries thicken, cholesterol levels rise, and - crucially - their heart cells become damaged. As a result, cells stop making a series of key proteins needed for their survival.

'It is downhill after that,' Smith said. 'The patient becomes a heart attack timebomb. Their cells perform less and less well, until full cardiac arrest ensues.'

In a bid to understand this cascade of cardiac disintegration, Smith and his team have studied biopsies from coronary bypass patients. In each case a few hundred cells were taken from the heart's complement of 10 million. Using these, the team pinpointed a key protein, Serca-2, that determines the health of a coronary cell. In low levels, a person risks a heart attack. In elevated amounts, their prospects look good.

'It is one thing identifying a missing protein, it is a very different matter when you try to put it back in a cell,' Smith said. 'However, we believe we have found a way, using genetically modified viruses.'

Viruses infect our bodies by inserting DNA into our cells, which then begin to manufacture fragments of virus. By adding a gene for a particular protein to the virus, an infected cell will then be persuaded to manufacture that protein as well.

Experiments by Smith and his team, using viruses, genetically engineered to make the heart protein, are getting heart cells, grown in the laboratory, to resume manufacture of normal levels of Serca-2. The final phase will be to launch clinical trials on humans.

'It is a controversial idea,' Smith said. 'A related project in America was recently suspended when a patient died. However, we will be proceeding very cautiously. In addtion, any virus used on a human patient will have been disabled so it cannot reproduce inside their bodies.'

The Glasgow project has also developed a test to detect when heart cells have become seriously damaged and which can therefore predict when a person is at imminent risk of having a major coronary. 'We found that cells in a diseased heart release large amounts of a protein - called BNP, brain natriuretic peptide,' said Professor Henry Dargie, leader of this part of the project. 'We use that as the test.'

The end result, say the Glasgow researchers, will be a test that will pinpoint potential heart attack victims, and the development of techniques that may counter their condition.

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