LOS ANGELES (AP) - A team of scientists says it has grown everything from human muscle to bone from stem cells taken from fat - a breakthrough that could eliminate the controversial use of fetal cells in the quest to mend damaged, missing or dead tissue.
Researchers at the University of California at Los Angeles and the University of Pittsburgh isolated the stem cells - immature cells that can be coaxed into maturing into specific types of tissue - from ordinary fat removed by liposuction. They then grew the cells into bone, cartilage, muscle and fat.
Stem cells have been taken previously from bone marrow, brain tissue and aborted fetuses and frozen embryos - a practice opposed by many anti-abortion groups. The use of fat as a source could end such controversy.
The study was published Monday in the journal Tissue Engineering.
Researchers predict the first practical use of laboratory-engineered tissue could come within five years. Eventually, scientists hope to use a patient's own fat to supply the tissue required to treat disease or repair injuries.
``We hope one day to be able to remove diseased tissue or organs, harvest stem cells and replace the lost tissues on the same day during the same operation,'' said Dr. Marc Hedrick of UCLA. ``There is potential for regenerating a lot of different tissues, perhaps some day solid organs, glands, nerves or brain tissue.''
Dr. J. William Futrell, a plastic surgeon at the University of Pittsburgh and a member of the research team, said it is too soon to say how the quality of stem cells from fat will compare to those from embryonic cells.
However, the fact that fat cells are so abundant could make them a ready source of material for a biotech industry interested in engineering new human tissues.
``Fat is something that is universal,'' Futrell said.
Dr. Mary Hendrix, head of the department of anatomy and cell biology at the University of Iowa, said the study adds to the growing evidence that adult stem cells can be as easily manipulated as embryonic cells.
``This is a very exciting discovery, because it's adding to our knowledge base of the potential of adult cells to provide a stem cell population,'' said Hendrix, who was not involved with the research.
The benefits could be twofold. The fat removed from a patient's beer gut, for example, could be used to repair that person's bum knee.
The discovery comes at a time when President Bush has signaled he may block federal funding for studies that use embryonic or fetal cells. He wants scientists to focus on adult stem cells, which until now have been more difficult to harvest.
There are drawbacks to harvesting stem cells from a patient's own body.
In severely ill patients who need large amounts of tissue replaced, doctors may not be able to grow sufficient stem cells quickly enough, according to the National Institutes of Health's guidelines on human stem cell research.
And in any disorders caused by genetic defect, the genetic error could be present in the cultured stem cells, making them inappropriate for transplantation.
Still, scientists look to stem cell research and its promise as a potential cure for Alzheimer's disease, diabetes, cancer, Parkinson's disease, heart disease and spinal cord injuries.
Editor's note: Associated Press writer Leon Drouin Keith contributed to this report.