Turning Fat Into Muscle ... and Bone ... and Blood Cells

From the WebMD Archives

April 10, 2001 -- Finally, modern medicine has something good to say about fat.

Current research shows that it is an excellent source for bone, cartilage, muscle, and maybe even blood cells. Or more precisely, it is an excellent source for stem cells that can be prompted to develop into bone or muscle, says Marc Hedrick, MD, a plastic surgeon at UCLA who has been studying fat for the last three years. He and his colleagues report their research in the April issue of Tissue Engineering.

As a plastic surgeon, Hedrick regularly uses liposuction to remove fat from abdomens, thighs, arms, backs -- any place where an unsightly bulge can be found. "And the fat that was removed was all just thrown away," he says.

Until now, that is.

Hedrick and his colleagues first began investigating liposuctioned fat to find out if it could be used to grow new fat cells that could then be used to treat people who have "rare fat wasting disorders. ... [Then, while] looking at some fat cells under a microscope, I noticed some of the cells [had characteristics] that looked like nerve or bone cells," he tells WebMD.


That led Hedrick to theorize that fat tissue, called adipose tissue, might be a source of stem cells -- the so-called primitive cells that can be stimulated to grow into specific types of cells like bone cells or muscle cells. Currently the best source for stem cells is bone marrow, says Hedrick. The other source is fetal tissue but controversy has slowed or stopped this research.

"Liposuctioned fat is an excellent alternative source," says Hedrick who points out that liposuction can be performed in doctor's offices with little risk or discomfort to patients.

Hedrick, and his colleagues from the University of Pittsburgh, harvested bone, muscle, nerve, and blood vessel cells from fat and "grew out these cell lines in the laboratory."

Farshid Guilak, PhD, director of orthopaedic research at Duke University's School of Medicine in Durham, N.C., says Hedrick's study confirms similar work by his team at Duke. "This is very gratifying to find confirmation from another laboratory," Guilak tells WebMD.


While Hedrick's team is interested in several different types of stem cells, Guilak's group is concentrating on growing cartilage from fat. He said that although all types of cells are plentiful in fat, "the first clinical application may be for cartilage."

His group is planning to begin studies in mice to determine if the cells harvested from human fat can "lay down new cartilage in an injured joint."

Guilak says he is "concentrating on fat obtained from abdominal fat deposits. I suspect that there are differences in fat based on its location ... in the body."

Hedrick says that his team is "using fat from all over the body." He, however, says that it is unlikely that fat composition differs by location.

Both Hedrick and Guilak say that tests in humans may be at least five years away. Moreover, Hedrick says that the "first human use for adipose-derived stem cells will be for autologous transplants." That means that cells will be transplanted into the same person who had the fat removed. Autologous transplants don't run the risk of tissue rejection that is associated with donor transplants, he says.


That's too bad for people who were planning to make deposits at a fat bank, but the good news is that Hedrick says fat banks are a real possibility for the future.

"At some point it may be possible to use cells harvested from donor fat for transplants, but not until autologous transplants are successful," Hedrick says.

Meanwhile, for the ecologically minded, Hedrick says, the "novel concept here is that we are taking something that was thrown away -- fat -- and breaking it down into component parts for reuse."

It is, he says, the ultimate recycling project.

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