Organs grown from cells signal new transplant era

The world's first organs grown in a laboratory have been successfully implanted in humans, heralding a new era in transplant surgery.

Seven patients given new bladders grown from their own cells have functioning organs that have performed as well as those conventionally repaired but with none of the ill effects, scientists have revealed.

Experts hailed the "stunning" development, which marks a new frontier in the search for replacement body parts. Scientists behind the breakthrough are now trying to grow up to 20 other organs and tissues.

Throughout the Western world, thousands of people die every year waiting for donor organs and thousands more never make it on to the waiting-lists; the potential benefits are enormous.

Instead of relying on organs from other bodies, doctors are investigating replacements grown by farming human tissue.

Anthony Atala, director of the Institute for Regenerative Medicine at Wake Forest University School of Medicine, North Carolina, who led the trial, said it was a vital step forward. "We have shown regenerative medicine techniques can be used to generate functional bladders that are durable," he said.

"This suggests regenerative medicine may one day be a solution to the shortage of donor organs in this country for those needing transplants."

Professor Atala is working on growing 20 tissues and organs, including blood vessels and hearts, in the laboratory.

Catherine Kielty, professor of medical biochemistry at the UK Centre for Tissue Engineering at Manchester University, said: "It is an exciting development. To my knowledge, a whole organ grown in the laboratory has not been tested in humans before. It is an engineered organ which has proved functional."

The development could be useful in other areas, such as growing small blood vessels and "plumbing in" kidney transplants where there is a need for elastic tissue, Professor Kielty said. But longer-term studies of the bladder wall were necessary to see if it continued to grow normally.

Professor John Dark, a cardiac surgeon at the Freeman Hospital, Newcastle, described the result as stunning but said it would be a big step to grow more-complex organs.

"The liver grows itself like the tail of a lizard," he said. "But growing organs with complex, different parts is much more difficult. The key thing about the heart is getting it all to beat together in synchrony. I would be cautious about the potential of this."

In the trial, the seven patients, all aged between 4 and 19, had engineered bladders grown from their own cells so there was no risk of rejection. A tiny sample of cells was taken from each patient's bladder by biopsy and grown on a biodegradable "scaffold". Elastic, smooth muscle cells were grown on the outside and epithelial cells forming the bladder lining on the inside.

After seven to eight weeks in the laboratory, the fully grown bladder was transplanted and stitched to the patient's existing bladder to create an enlarged organ.

After up to seven years of follow-up, long-term results published in the online edition of the British medical journal The Lancet showed the new bladders functioned well and did not have the side-effects such as kidney stone formation associated with conventional repair with intestinal tissue.

Professor Atala said: "We wanted to go slowly and carefully and make sure we did it the right way. This is a small, limited experience but it has enough follow-up to show that tissue engineering is a viable tool."

All the patients were born with a congenital defect, spina bifida, which is associated with poor bladders.

Repair of the bladder with intestinal tissue has been done for more than 100 years. But because the intestine is designed to absorb nutrients and the bladder to excrete, patients who have the procedure are prone to problems such as osteoporosis, increased cancer risk and the formation of kidney stones.

- INDEPENDENT