An Australian scientist says he has discovered a key factor in high blood pressure.

Professor Brian Morris and his team from Sydney University published Monday the results of their study, which identified the role of the enzyme renin in triggering high blood pressure

The research studied the impact of renin on human kidneys, which Morris started studying in the early 1970s. Although renin was believed to have played a major role in the elevation of blood pressure, precisely how it worked remained a mystery to science until now.

The team found that for people with hypertensive kidneys, the renin gene was six times more active while the micro-RNAs were six times less active. The two micro-RNAs are very much lower in hypertensive people and if they lose the two, their renin goes up and boosts blood pressure.

The discovery of the role of the two micro-RNAs could lead to the development of hypertensive drugs designed to hit the renin expression at its source, Morris said.

Although kidneys had long been suspect of being the reason behind elevated blood pressure, studying human kidneys was difficult because of the scarcity of this human organ for medical research. A donation of 42 kidneys from Polish cancer patients who had the vital organ removed for medical reasons helped the Sydney researchers study renin, said PhD student Francine Marques.

According to the latest statistics, 18 per cent or 3.5 million Australians suffer from long-term cardiovascular conditions, with 11 per cent or 2.1 million classified as hypertensive.

The study came out Monday in Hypertension journal's online edition. The journal is published by the American Heart Association.

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