 |
 |
|
| Archive : Winter 2006 |
THE NEW TOOLS OF RECONSTRUCTION:
Skin from a deceased donor's face // Fat // Milled bone chips // Resorbable tacks // Fibrin glue // Biodegradable scaffolding // And most critical, not expecting too much too soon.
Saving Faces [page 4]
 By Anita Slomski
|
|
|
Vacanti and his brother Charles pioneered the field of tissue engineering along with two of their brothers during the mid-1980s and are still among its leading lights. Using a combination of biodegradable polymer scaffolding and chemical compounds to urge cells to grow outside the body, the Vacantis are responsible for such medical feats as rebuilding a 12-year-old's deformed sternum and chest wall with the boy's own cartilage cells; using bone-marrow cells and sea coral to fashion a thumb for a man who severed his in an accident; and getting paraplegic rats to walk after implanting lab-grown spinal-cord tissue.
While the transplant of a bioengineered liver grown on a lab bench may be years away, other researchers have made strides in creating less complex autologous body parts such as ears, which don't need a blood supply and can survive by diffusion from surrounding tissues. Yaremchuk has made vast improvements to an ear grown from cartilage cells in 1995 by Charles Vacanti, now chairman of the anesthesiology department at Brigham and Women's Hospital. Using a quarter-inch piece of cartilage from behind the ear or inside the nose, Yaremchuk has been able to grow a human-size, flexible ear by seeding chondrocytes—cartilage cells—on a degradable ear-shaped polymer matrix and laminating them between layers of swine perichondrium, the connective tissue that surrounds ear cartilage.
"The standard approach for creating a replacement ear is to make a big incision in someone's chest, harvest cartilage from two ribs, carve it up, join it with wires and sutures in the shape of the ear and cover it with tissue from the ear area," says Yaremchuk. "But that's very tedious, there is deformity where you harvested the cartilage, and only a few people are really good at it. Now we can make an ear from 1,000 cells instead of eight inches of rib cartilage." Yaremchuk is also working on injectable cartilage that can resurface arthritic joints, potenti-ally saving millions of people from knee and hip replacements.
With most medical breakthroughs come concerns about moving too quickly or provoking unintended consequences, and these advances in reconstructive surgery are no exception. In the case of Howaldt's stem-cell work, for example, Gregory Evans, chief of the Aesthetic and Plastic Institute at the University of California at Irvine, thinks more must be known about the underlying science before large-scale human trials begin. "There is a big jump from converting adipose-derived stem cells into other types of cells and having them actually function as nerve, muscle, cartilage or bone. It may be that adult stem cells have already differentiated too far while they are in fat to truly change into a new cell," says Evans.
Yet Evans, who is studying whether adipose stem cells can transform into nerve cells, remains guardedly optimistic. "Even though our criteria for using these advances may change drastically during the next few years, adult stem cells and tissue engineering have great potential for all of medicine," he says.
Facial transplantation, too, could have far-reaching implications. Beyond transforming the lives of disfigured patients, it might pay unexpected dividends. For example, if Siemionow's work leads her or others to conquer the perils of immunosuppression, it could dramatically improve the prospects for transplanting not only faces but also organs, hands, skin, nerves, muscles and bones.
 Dossier
1. Allotransplantation of the Face: How Close Are We? by Maria Siemionow and Galip Agaoglu, Clinics in Plastic Surgery, 32 (2005). Excellent overview of the medical advances that have made the face transplant possible and the challenges that remain.
2. On the Ethics of Facial Transplantation Research, by Osborne P. Wiggins et al., American Journal of Bioethics, 4 (3) (2004). Detailed assessment by the University of Louisville transplant team of the risks of a transplant, followed by valuable commentary from supporters and critics.
3. Tissue Engineering: The Design and Fabrication of Living Replacement Devices for Surgical Reconstruction and Transplantation, by Joseph P. Vacanti and Robert Langer, The Lancet, 354(suppl1) (1999). Comprehensive description of the history and techniques of tissue engineering.
|
More
|
Back to top | Pages: 1 2 3 4
Left to right: Photo by Erin Patrice O'Brien/Getty Images; Photo by Erik von Weber/Getty Images;
Photo by Erik von Weber/Getty Images; Photo by David Sacks/Getty Images
|
|
|
|
