Stem cells turn into breast implants * 12:51 18 February 2005
* NewScientist.com news service
* Will Knight, Washington, DC
Silicon breast implants could be replaced by tissue grown from a person's own stem cells within a decade, suggests new research.
Jeremy Mao of the University of Illinois, in Chicago, US, took human stem cells and used these to grow fat tissue using a biologically compatible scaffolding. He then successfully implanted the tissue into mice with an immune deficiency to prevent them from rejecting the implants. The implants had maintained their size and shape after four weeks.
"This is a project that builds on previous knowledge to develop a stem cell material that could be useful in society," says Mao. "It seems promising and could soon be making an impact."
Implants grown from stem cells could provide a safer alternative to silicon or saline implants, which can rupture and also interfere with breast cancer detection. They could also be aesthetically superior, keeping their shape and size for longer than artificial inserts, which typically shrink by 40% to 60% over many years, through spreading.
Reconstructive surgery
Eventually Mao says the technique could be used to develop more suitable tissue for reconstructive surgery as well as cosmetic augmentation.
The experiment involved key-hole surgery to extract mesenchymal stem cells from human bone marrow. These "master cells" can grow into various other different types of cells, including bone cartridge and fat. Mao coaxed them to develop into fat cells by mimicking the conditions that would cause this to happen in the human body.
The cells were then moulded into shape using a hydrogel scaffold and inserted into mice for a period of four weeks. Following implantation the eight mice involved in the study suffered no discernable ill effects and their implants maintained their original size and shape for the entire month. This is substantially longer than artificial inserts, which normally begin to deform after a week or two.
Mao believes breast implants grown from stem cells could be available within a decade. Ideally, the scaffold would disintegrate safely inside the body as the implant grows, he says.
Growth factors
But he admits that several questions remain over the viability of grown implants, including how they will react to surrounding tissues and whether any special growth factors might be required.
Donald Ingber, of Harvard Medical School, part of Harvard University in Massachusetts, US, says the work, which will appear in the April issue Tissue Engineering, is promising. But he cautions that more complex cell techniques may be needed to grow viable implants for humans. "The breast is more than just fat," he says. "And you might want specific patterns of growth rather than just growth."
But Ingber told New Scientist that it might be possible to engineer controlled growth using alternative types of scaffolding or by chemically treating surrounding cells so that they manage the growth of the new ones.
Mao presented the work at the American Association for the Advancement of Science conference in Washington, DC, US, on Thursday.
Finally we're getting to the important applications of stem cells.
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