Adult stem cells may offer a remarkable new way to assist reconstructive surgery. The technique would allow natural breast implants to be grown back into place after mastectomy, or the replacement of complex soft tissues such as lips after burns.
Researchers at the University of Illinois provided details of their work at the American Association for the Advancement of Science's annual meeting, which opened yesterday in Washington DC.
Prof Jeffrey Mao described how his team successfully grew new replacement fat cells and was able to control their shape in mouse models. It represents a proof of principle that in time could greatly improve results available with tissue reconstruction after accident or cancer treatment. It could also benefit cosmetic surgery including wrinkle removal and breast augmentation.
Breast replacement currently involves either silicon implants or the use of natural cell implants, but both have disadvantages, Prof Mao said.
Artificial implants can burst and may obscure the ability to detect developing cancers. Cell implants tend to shrink, losing 40 to 60 per cent of their original volume over time.
He took a different approach, collecting mesenchymal stem cells from adult bone marrow and then using them to "seed" a liquid hydrogel already approved for human use by the US Food and Drug Administration. The hydrogel acts as a scaffold into which the stem cells can grow and develop, he added.
Stem cells can change into many types of cells. Prof Mao used growth factors to encourage them to form adipose or fat cells. The pre-shaped scaffold seeded with stem cells was then inserted into mice.
"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. "The great thing about the stem cell-derived implant is that its shape and dimensions were retained."
A great advantage of this approach is the recipient's own cells could be used for the cell donation, eliminating the risk of rejection. Prof Mao sees it used, for example, in breast reconstruction after cancer surgery.
"You would mould the [scaffold and stem cells] into the shape of the other, normal, breast or the missing portion of breast, and instead of implanting silicon or saline structures, use the stem-cell derived adipose implant. The technique is also applicable for other soft tissue, facial tissue like the lips and so on."
It is hoped that the hydrogel scaffold would degrade and disappear at a similar rate to cell growth and the cells' production of "extracellular matrix", the flexible material that surrounds and supports cells in place.
It could take 10 years before a technique like this is applied to humans, Prof Mao said. It holds great promise, however, and would give patients a choice of "a stem cell-grown structure or an artificial implant" he added.