Grow-your-own transplant organs

Plastic surgery might soon involve transplants of skin and tissue reconstructed from bone marrow cells taken from a patient and grown artificially in the laboratory.

Scientists announced at the weekend that they have taken stem cells from a human donor and stimulated them to develop into the fatty tissue of the skin - a development that could allow patients to grow their own replacement organs for transplant surgery.

One possibility is that female cancer patients having a mastectomy could have their own breast replacements grown artificially for reconstructive surgery, said Jeremy Mao, professor of tissue engineering at the University of Illinois in Chicago.

Details of the breakthrough, given at the American Association for the Advancement of Science in Washington, reveal that it is possible to isolate the key stem cells in bone marrow, grow them in the laboratory to develop into the fatty or adipose tissue of the skin, and build it around a "scaffold" to the desired shape.

"What we have done is to take adipose stem cells from a human donor and differentiate them into adipocytes, or fat-generating cells," Professor Mao said. "We have then seeded these on to a liquid hydrogel scaffold, which can be moulded into any given shape or dimension."

Hydrogel is a lightweight material that is already licensed for use in medicine.

The scientists implanted the hydrogel scaffolds containing the living fat cells into laboratory mice lacking immune systems, which meant they did not reject the human tissue implants.

"After four weeks we found that the implant was indeed generating adipose tissue from stem cells, and that its shape and dimensions were well retained," Professor Mao said.

"What we foresee for humans is that, say a woman needs breast reconstruction, you can take adipose stem cells from her and do the same procedure.

"You would mould them into the shape of the other normal breast, or the missing portion of breast, and instead of implanting silicone or saline structures, we would use the stem cell-derived adipose implant."

About 6.2 million people in America alone need plastic surgery for medical reasons and about 70 per cent of them because of the removal of a tumour. About as many again have plastic surgery for cosmetic reasons.

Professor Mao said that growing replacement tissue from a patient's own stem cells would overcome the problems of tissue rejection that arise from tissue derived from a donor.

"The technique is also applicable for other soft tissue - facial tissue like the lips and so on.

"The great thing about the stem cell-derived implant is that its shape and dimensions are retained. You could do a liposuction, harvest the stem cells, and use them for regeneration of the other structure. It could certainly be combined with other techniques.

"Patients will have a choice - a stem cell-grown structure or an artificial implant. It will be a similar situation to other elective surgery compared to otherwise medically necessary surgery.

"It would be up to the patient. A lot would depend on how things were presented to the patient," he said.

"Much of how fast this will progress is a matter of regulatory issues that are hard to predict. The technology should be mature within a decade."

- INDEPENDENT