Scientists believe they have found a source of master cells for treating future heart problems, from human veins left over from lifesaving bypass surgery.

The journal Circulation reports a University of Bristol research team extracted stem cells from the veins and successfully used them to stimulate new blood vessel growth in mice.

The researchers believe their findings have brought them one step closer to finding a treatment to repair damaged heart muscle, though a stem cell expert warned it would take some years, yet.

Medical researchers find stem cells attractive, because they are able to produce many different types of human cell, opening up the possibility of repair or renewal of tissues ravaged by disease or injury.

While, human embryos were originally considered as the prime source of ‘pluripotent’ cells, with the potential to form virtually any tissue type, increasingly scientists are finding ways of isolating cells from adults having some of these properties, and encouraging them to multiply into useful numbers.

Their latest discovery has been to use a waste product from thousands of heart operations carried out each year. Often, patients with heart disease have blocked or narrowed arteries that supply the heart muscle. Lack of blood leaves the muscle damaged, which can cause chest pain or even a heart attack.

In a heart bypass operation, a section of vein, usually from the patient’s leg, is used to replace a blocked or narrowed section of heart artery, with the surgeon taking a slightly longer section than actually required.

In their study, the team of Bristol researchers taking the leftover piece in the laboratory managed to extract ‘progenitor’ cells from the veins, and persuaded hem to increase in number, in the laboratory.

When injected into the leg muscle of a mouse deprived of blood for stimulating conditions in a damaged heart, the stem cells triggered the development of new blood vessels and improved blood flow.

These cells might make it possible for a bypass patient to also receive heart treatment using their body's own stem cells.

However, much more work is needed before such cells can be used widely in humans.