It could be one of the best examples of medical recycling ever. Normally, the excess fat cells removed during liposuction are deposited in specialized biohazard containers and designated as medical waste. They are usually sent to industrial landfills for incineration.

But now, according to UCLA scientists, those fat cells removed by liposuction may become human pluripotent stem cells, capable of regenerating into virtually all cell types in the human body, including muscle, bone, cardiac, neuronal and liver cells.

The Muse-AT cells were discovered by accident. When the scientists’ lab equipment failed.

Human pluripotent stem cells are considered the holy grail of regenerative medicine because, in theory, they could be used to create new organs that could be transplanted into the human body to replace broken or used ones. They can also be used to treat certain types of fatal disorders such as sickle cell anemia.

A Serendipitous Discovery

The team of researchers from UCLA’s Department of Obstetrics & Gynecology discovered that cells isolated from fat, or adipose tissue, removed during liposuction could form a special type of stem cell called Multi-lineage Stress-Enduring (Muse-AT) stem cells. These Muse-AT cells expressed many markers of embryonic stem cells and are capable of forming layers of specialized tissue – either muscle, bone, fat, cardiac, neuronal or liver – when transplanted into the body of an animal.

The cells can be grown using very simple laboratory techniques that take a maximum of six hours, and do not require the use of more high-tech and expensive equipment.

The Muse-AT cells were discovered by accident. When the scientists’ lab equipment failed, all of the stem cells growing in Petri dishes were killed — except the Muse-AT cells. That fact indicated the cells were capable of surviving in extremely stressful conditions, once thought to be an advantage only cancer cells had. In fact, the researchers believe that Muse-AT cells lie dormant in fat tissue until they are activated by stressful conditions.

Even better, the researchers showed that Muse-AT cells can be grown using very simple laboratory techniques that take a maximum of six hours, and do not require the use of more high-tech and expensive equipment, such as cell sorters, to isolate them.

Currently, there are two main sources of pluripotent stem cells: embryonic stem cells and induced pluripotent stem (IPS) cells. The use of embryonic stem cells is controversial for ethical reasons. IPS cells can be derived from other parts of the body such as skin and wisdom teeth.

One Problem: Uncontrolled Growth

A drawback with both of these cell types is that they exhibit uncontrolled proliferation and cause tumors known as teratomas. The likelihood of these tumors severely limits the use of pluripotent stem cells in humans. It is encouraging that a stress-resistant population of stem cells from bone marrow discovered by Japanese researchers do not produce teratomas in animal models, and the UCLA researchers hope this means that their own fat-derived Muse-AT cells will not produce teratomas either. For the time being, however, science has not yet found a solution to this problem, despite some promising possibilities.

“Upon further investigation and clinical trials, these cells could prove a revolutionary treatment option for numerous diseases, including heart disease, stroke and for tissue damage and neural regeneration, ” said Gregorio Chazenbalk, an associate researcher with UCLA Obstetrics and Gynecology.

One issue with these cell types is that they exhibit uncontrolled proliferation and cause tumors known as teratomas.

Future studies by the UCLA team will attempt to inject Muse-AT cells in animal models to see whether they repair damaged or dysfunctional organs. The experiments must be able to gauge how well the cells grow and function inside a living organism instead of just a Petri dish. They also must test whether the cells produce those unwanted tumors.

But for now, the idea that cells from liposuction – a safe, non-invasive procedure – can produce pluripotent stem cells has the stem cell field very excited. “Muse-AT cells have the potential to make a critical impact on the field of regenerative medicine,” Chazenbalk said.

The study appears in the journal, PLOS ONE.