Ride For Life: Liposuction a new source for stem cells?

Copyright 2004 P.G. Publishing Co.
Pittsburgh Post-Gazette (Pennsylvania)
October 5, 2004 Tuesday SOONER EDITION
SECTION: HEALTH, Pg.A-1
LENGTH: 848 words
BYLINE: BYRON SPICE, PITTSBURGH POST-GAZETTE

Most people are more than happy to get rid of extra body fat. A select few researchers, many of them gathered in Pittsburgh this week, are more than happy to take it.

Fat tissue contains adult stem cells and researchers are finding that the cells have potential for regenerating damaged hearts, reconnecting severed nerves and reconstructing breasts following cancer surgery.

With almost 400,000 Americans undergoing liposuction last year to improve their looks, the idea of using some of that fat to cure a disease or defect has lots of popular appeal -- so much that some scientists initially refused to take seriously the whole field of fat stem cells.

"Now I think we're coming into the mainstream," said Dr. Adam Katz, a University of Virginia plastic surgeon. Stem cells derived from fat -- or, adipose tissue, as scientists like to call it -- are not only easy to obtain, but seem to lend themselves to a number of potential uses.

"People in some of the other adult stem cell areas are beginning to pay attention," he said.

About 80 researchers have gathered at the Sheraton Station Square Hotel Pittsburgh for a two-day meeting of the International Fat Applied Technology Society, which concludes today. In addition to sharing their latest findings, they hope to reach a consensus about what these fat stem cells are and lay out a framework for future research.

There is no shortage of material for researchers.

"We get hundreds of millions of cells each week" thanks to patients undergoing cosmetic liposuction, said Kacey Marra, director of the University of Pittsburgh's Plastic Surgery Research Laboratory. "We have people volunteering to donate every day."

Stem cells are a primitive cell population that can give rise to a variety of specialized tissues. Stem cells from embryos have garnered much attention and controversy because they supposedly can be used to regenerate almost any tissue type, but can be obtained only by sacrificing human embryos. Adult stem cells, such as those from fat, are easier to get, but are thought to have more limited potential.

Just what the limits are is not clear. Dr. Henry Rice, a pediatric surgeon at Duke University Medical Center, said his group has seen some evidence of fat stem cells transforming into neuronal cells, both in cell cultures and in animal experiments.

If such a transformation is possible, "it would challenge a lot of scientific dogma," Rice said. Fat cells belong to a lineage that includes muscle, bone and connective tissue, while nerve cells are in a separate lineage that includes skin, hair and teeth.

"This is work to be challenged," Rice said, acknowledging that some researchers have strong doubts that such a transformation is possible. He isn't sure himself; he claims only that the cells seem to have the characteristics of a nerve-like cell.

But even if the stem cells can't directly regenerate non-fat-related tissues, they may well have powerful "chaperone effects." It may be that the fat stem cells, when placed in a damaged tissue, somehow trigger repair mechanisms in surrounding cells.

Katz is collaborating with researchers trying to use fat stem cells to repair heart muscle damage and has similar observations. They know the cells remain in the heart, "but we have not been able to find evidence that they are turning into heart muscle," said Katz, a former Pitt researcher who was a member of the team that discovered fat stem cells three years ago.

The stem cells may stimulate the heart cells to regenerate themselves by causing or inhibiting inflammation, by emitting growth factors or by simply touching the adjoining cells, he suggested.

In some cases, it's still too early to say what is happening. At Pitt, Marra has used fat stem cells to try to reconnect severed peripheral nerves. The nerves normally can reconnect themselves over short distances, but she has been using polymer tubes filled with fat stem cells to bridge gaps of more than an inch.

The results in rodents are still preliminary, but it appears that after three months the stem cells are still in place and still alive, Marra said.

"Just survival is significant in itself," Rice said. The nervous system, he explained, doesn't normally welcome cells from other tissues.

Though many people want to get rid of fat, one of the most promising uses for fat stem cells may be the regeneration of fat, said Dr. J. Peter Rubin, a Pitt plastic surgeon.

Each year, 80,000 U.S. women undergo breast reconstruction for breast cancer, he noted. It might be possible to use fat stem cells, removed during a liposuction and then processed and grown in culture, to rebuild breasts, rather than using flaps of belly fat as is one current practice, Rubin said.

As yet, Katz said, animal studies haven't revealed any major safety problems associated with stem cells, such as tumors. But the long-term safety remains a question, he acknowledged. The stem cells seem to encourage the growth of new blood vessels, a factor that might increase cancer risks, he added.

NOTES:
Science Editor Byron Spice can be reached at bspice@post-gazette.com or 412-263-1578.

LOAD-DATE: October 5, 2004

Document 4 of 13