World first trial grows blood vessels from patient's own skin

Nov 16 2005

A team of American scientists have successfully implanted blood vessels grown entirely from a patient's own cells.

In this the first clinical trial of its kind, two patients have so far received transplant blood vessels that were grown in a dish from a clump of their own skin cells.

It seems that both the patients are progressing well after their operations and the blood vessels are apparently performing "perfectly".

The veins were created in a laboratory by scientists at Cytograft Tissue Engineering, a biotechnology company based in California, before being transplanted into patients undergoing kidney dialysis to test whether they could withstand high blood pressures.

The team is now about to embark on an unprecedented trial at Papworth hospital in Cambridge, which will see lab-grown blood vessels used in heart bypass operations for the first time.

According to Dr Todd McAllister, who announced the results of the on-going trial at the annual meeting of the American Heart Association in Chicago this week, the trial is a world first and the results to date are extremely encouraging.

Apparently the blood vessels are made by taking a half-centimetre square sliver of skin, rich in cells called fibroblasts, from the back of a patient's hand.

By then growing the fibroblasts in a dish, the researchers were able to create large sheets of cells held together by collagen, the protein that gives skin and blood vessels their strength.

The thin sheets of tissue were then wound around a pencil-like cylinder before being treated to fuse the layers together, forming a tough tube of tissue.

The inside of the new vessel is then coated with endothelial cells taken from veins to stop blood clotting.

Dr McAllister says this process takes six months.

The researchers believe that although the veins the team have grown so far have been around 25cm (about 10ins) long, lengths of up to a metre are possible.

Bruce Rosengard, a cardiothoracic surgeon at Papworth hospital who is running the British trial, says the results are encouraging and they are actively looking for patients for the new trial.

Rosengard says the fact that this is a living tissue is promising and there are good reasons for it to succeed.

The trial at Papworth it seems will initially use lab-grown veins to replace those taken from the legs and arms of people for heart bypass surgery.

The blood vessels have the potential to be used in a number of different operations, most promisingly in children born with congenital heart defects.

Instead of being fitted with artificial blood vessels that need to be replaced with bigger versions as the child grows, lab-grown blood vessels could replace dangerously deformed veins in one operation because they are made from living tissue that grows with the body.

Another target group are diabetics who face limb amputations because the blood vessels in their legs have deteriorated as a result of their condition.