Stem cells can rebuild heart muscle

Two teams of scientists have made independent breakthroughs using stem cells to repair cardiac muscles damaged by heart attacks. They have shown in experiments on mice that heart muscle can repair after injections of stem cells. The stem cells used in the experiments were derived from the bone marrow of adult mice or taken from human volunteers and have shown the first unequivocal results that adult stem cells (rather than embryonic stem cells) are capable of repairing cardiac tissue.

The team that used the human stem cells are from Columbia University in New York, led by Silviu Itescu. A team led by Donald Orlic of the US National Human Genome Research Institute and Piero Anversa of New York Medical College transplanted adult stem cells taken from mice. Dr Orlic said that more than two-thirds of the damaged sites were 'invaded' by the injected stem cells. This caused some of the cardiac muscle and oxygen-supplying blood vessels to regenerate.

On the potential of adult stem cells Dr Anversa said 'our results indicate the great potential of adult stem cells to differentiate into other cell types and repair a damaged organ, a property commonly attributed to embryonic stem cells. This may allow us to utilise a patient's own stem cells'.

The findings of the studies has surprised the scientists as the evidence was beyond their expectations, showing that the damage caused by heart attacks could be reversed. It is now hoped that clinical trials on human heart attack victims will begin within three years.