Researchers at the Children's Hospital of Pittsburgh said the newly identified adult stem cells have the unlimited potential to differentiate into human tissues such as bone, cartilage and muscle.

The scientists, led by Bruno Peault, deputy director of the Stem Cell Research Center at the hospital, identified cells known as pericytes, which have broad developmental potential. The researchers said pericytes are found on the walls of small blood vessels such as capillaries and microvessels throughout the body and have the potential to be extracted and grown into many types of tissues.

"This finding marks the first direct evidence of the source of multi-potent adult stem cells known as mesenchymal stem cells, said Peault. "These cells can be extracted easily and painlessly from convenient sources such as fat tissue, dental pulp, umbilical cord and placental tissue, then grown in culture to large numbers and, possibly, re-injected into the patient to heal a broken bone, a failing joint or an injured muscle," Peault said.

Results of the study appear in the journal Cell Stem Cell.