A world-first clinical trial with adult stem cells has helped six patients with severe heart disease, Australian scientists claim. Doctors at a hospital in Newcastle, north of Sydney injected a rare type of adult stem cell, mesenchymal precursor cells, taken from the patients' own bone marrow, into damaged heart tissue. Afterwards they reported having fewer angina attacks, taking less medication, and having improved heart function.

The next phase of the research will involve donor tissue, as bone marrow in older patients with heart disease is "not the best", said cardiologist Suku Thambar.

Embryonic stem cells are also in the news this week for curing heart disease -- but in rats. In an article in Nature Biotechnology, scientists from the University of Washington and from the private biotechnology company Geron claim that the rats developed new heart muscle and were protected against the progression of heart failure. The study did not disclose what happened to the rats in the long term. This is a serious concern, because embryonic stem cells often form tumours with time.