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SILICONE breast implants could soon be unnecessary, claim researchers in
Australia. They say their work will make it possible for women to grow their
own.

Tissue engineer Kevin Cronin of the Bernard O’Brien Institute of Microsurgery
in Melbourne told delegates at a recent meeting of the Royal Australasian
College of Surgeons that he has successfully grown breast and fat tissue in
rats, mice and rabbits. If the technique works in people, it could be used for
cosmetic surgery or breast reconstruction after mastectomy.

Rather than growing the patient’s tissue in the lab and then transplanting it
back into the body, as has been done in animal studies in the past, Cronin grows
the tissue on site. A “chamber” containing a scaffold is implanted into the area
where new tissue is needed. Cells from surrounding tissue then migrate into the
chamber and form a three-dimensional blob of tissue, in what Cronin calls a
“wound-healing” response. Over time, the scaffold disintegrates.

The key to the technique’s success, says Cronin, is a “vascular loop” in the
chamber that generates new blood vessels to supply the growing tissue. But he
won’t reveal details about how it works or what it is made of until a patent has
been granted.

Cronin has already grown fat and breast tissues in female mice by implanting
the chamber into their groin fat pad. This area is on the animals’ “milk line”,
where the cells are pre-programmed to form breast and fat tissue. Growing human
breasts would involve a similar technique. Immune rejection wouldn’t be a
problem, but Cronin’s mice did occasionally develop infections around the
implanted chambers.

Dai Davis, a plastic surgeon from Stanford Hospital in London, says supplying
blood to the new tissue will be difficult. “We can move fat around [during
breast enlargements], but we can’t always vascularise it… it calcifies or just
disappears altogether,” he says. He also points out that there could be cancer
risks. “If you are using cells from a woman who has had breast cancer, how do
you know that the new tissue is not also going to turn into a cancer?”

Tissue engineer Julia Polak from Imperial College School of Medicine in
London agrees. “In the case of someone who has already had breast cancer, it
would be difficult to ensure that the cells used to regenerate the breast tissue
did not also contain the cancer-causing genetic machinery,” she warns. But she
says the technique does have potential. “It is certainly exciting. It is the way
tissue engineering should be going—getting the body to regenerate itself
rather than trying to grow complex body parts in a ‘test tube’.”

Cronin predicts that financial backing to develop his new technology will
centre on cosmetic surgery applications. “There is an obvious spin-off into
breast augmentation and facial aesthetic surgery,” he says. But he does admit
the end result could be hard to control. “We were just so happy at getting the
desired tissue to grow at all that we haven’t even got around to working out how
to control issues such as size and shape,” he says.