Fat: Source of Stem Cells

B O S T O N, April 10, 2001 -- You may have a little excess poundage in your middle section today. But someday that extra blubber could be your salvation.

Plastic surgeons at the University of California Los Angeles and the University of Pittsburgh say that all the fat they’ve been throwing away over 30 years of liposuction may be more valuable than ever imagined. It now looks as though some of that fat can be salvaged and reprogrammed to form muscle, bone, cartilage, and even more fat.

Dr. Marc Hedrick, a pediatric plastic surgeon at UCLA and the lead investigator in this tissue-engineering research, says that “fat is not the tissue we once thought. For too long it was seen as something to be removed and tossed away.

“We weren’t seeing its potential. We now know that it’s not just spare tissue, but rather a vigorous tissue capable of regenerating.”

The researchers had taken stem cells from human fat removed during liposuction and in test tube experiments saw these stem cells become other tissue. Stem cells are the unprogrammed master cells that mature to become different cell types in the body. Now, the researchers are taking stem cells from rat fat cells and placing these stem cells in different environments in the body to see if they become similarly transformed.

Details of this research appear in the April issue of the medical journal Tissue Engineering.

An Ethical Alternative

Stem cells, which until now only came from bone marrow, brain tissue, or fetal tissue, are believed by many scientists to be the greatest hope for curing many degenerative illnesses, such as Parkinson’s disease.

Unfortunately, there are obstacles. Aside from being in limited supply and difficult to harvest, there is a vigorous ethical debate about how and when, if ever, fetal stem cells — derived from abortions or excess embryos from in vitro fertilization — should be used.

“Until now, we hadn’t identified a good source of stem cells,” Dr. Hedrick says. “Fat may be the ideal source. It’s in plentiful supply, it’s easy to obtain, and relatively inexpensive compared to a bone marrow extraction.”

“And it may ultimately take the steam out of the stem cell/embryo debate, allowing people easy access to large quantities of their own cells.”

The work Dr. Hedrick and colleagues are spearheading involves harvesting the most immature fat cells — fibroblast-generating cells — from the tissue removed by liposuction. They are then placed into an environment conducive to their maturing into a specific type of tissue — muscle, bone, cartilage, or, yes, even fat.

An Answer to Breast Reconstruction

The cells are placed into specific areas of the body with the intent that they develop, grow, and ultimately repair or replace damaged, dead, or missing tissue.

“The goal,” Dr. Hedrick says, “is to be able to transplant these progenitor cells into specific areas of the body where new tissue growth is needed. One possible example of how they could be used is in breast reconstruction after surgery for breast cancer.

“Fat tissue and breast tissue are very similar. Placing these progenitor fat cells into the desired areas for breast development may provide a more natural approach to breast reconstruction.”

Dr. Hedrick said the research is currently moving forward in various larger animals, such as rabbits, and expects it to be ready for human testing within five years.

Scott Terranella is a third-year medical student at Emory University in Atlanta, and a news editor in the ABCNEWS Medical Unit.