Liposuction Fat Turned Into Stem Cells, Study Says

John Roach
for National Geographic News

A woman poses for a 2004 National Geographic magazine cover story.

Human fat can be a source of stem cells, a September 2009 study says. For example, someday it may be possible to grow new organs for patients from their own fat—and even thin people have enough fat for such a procedure, researchers say.

Photograph by Karen Kasmauski

September 8, 2009 Using leftovers from liposuction patients, scientists have turned human fat into stem cells, a new study says.

The new method is much more efficient than a previous practice that used skin cells, researchers say.

The discovery may also help avoid the controversy spawned by the use of stem cells from human embryos. (See stem cell research pictures.)

Human fat is "an abundant natural resource and a renewable one," said Stanford University plastic surgeon Michael Longaker, whose liposuction patients donated the fat for the study.

Longaker envisions a future in which doctors will be able to use fat from a patient to grow, in a lab, new tissues and organs for that patient.

The opportunity wouldn't be limited to the obese.

"Even if you're in great shape, there is still enough fat to be harvested from the vast majority of patients," added Longaker, who co-authored the study.

From Fat to Stem Cells to New Organs?

The reprogrammed cells, called induced pluripotent stem cells, or iPS cells, are capable of turning into most types of cells in the body.

Scientists are keen to obtain these cells to study disease and, one day, use them to grow new tissue and replacement organs.

Previously, researchers had shown that they could derive this type of stem cell from ordinary skin cells.

But the fat technique is about twice as fast and 20 times more efficient, said Joseph Wu, the study's senior author.

"We can get iPS-like colonies, basically, in about 16 days, compared to 28 days to 32 days using [skin]," said Wu, a Stanford stem cell expert. "And if you count the number of colonies in [skin] versus fat ... we get about 20 times more the number of iPS colonies."

The research appears online today in the journal Proceedings of the National Academy of Sciences.

Reprogramming Cells

To create the stem cells, the scientists injected Trojan horse-like viruses into smooth muscle cells found in fat that surrounds blood vessels. Once inside, the viruses introduced genes that reprogrammed the cells, spurring them to grow into new forms.

Previously, this process had required growing the stem cells in a culture dish with nutrients from mouse cells. This had raised alarms about the potential for contamination from mouse proteins—a potential obstacle to government approval, Longaker, the plastic surgeon, said.

That the new method works at all is "somewhat surprising" and remains something of a mystery, Longaker said.

Sidestepping Stem Cell Controversy

The fat and skin methods allow researchers to sidestep the ethical controversy over the use of embryonic stem cells from cell lines originally harvested from unused human embryos from in vitro fertilization clinics.

In addition, Longaker noted, tissue or organs grown from a patient's own stem cells should be less likely to be rejected by the body.

The speediness of the fat method, in particular, could be lifesaving, he added.

For example, if a surgeon wanted to implant new heart tissue—derived from a heart attack victim's own fat—into a patient, the doctor might have only a short time before scar tissue would compromise the operation.

If he or she were able to generate the tissue within a few weeks, Longaker said, that "would be a big deal."