WASHINGTON, Sept. 20 (Xinhua) -- A study published on Thursday in the journal Cell showed that human skeletal stem cells that become bone, cartilage, or stroma cells have been isolated from fetal and adult bones.
This is the first time that skeletal stem cells, which had been observed in rodent models, have been identified in humans, according to researchers at Stanford University School of Medicine.
The researchers were able to derive the skeletal stem cells from human induced pluripotent stem cells, opening up new therapeutic possibilities.
"Identifying this human skeletal stem cell and elucidating its lineage map will enable the molecular diagnosis and treatment of skeletal diseases," said senior study author Michael Longaker at Stanford University.
Bones in mice and humans can recover from small- to moderate-sized defects, but adult cartilage tissues possess little to no regenerative ability. Also, both mice and humans display severe age-related degeneration of skeletal tissues over time.
In the new study, Longaker and his collaborators found that those self-renewing and multipotent cells were present in both fetal and adult human bone marrow tissues and could be derived from induced pluripotent stem cells (iPSCs).
iPSCs are a type of pluripotent stem cell that can be generated directly from adult cells. Pluripotent stem cells can propagate indefinitely, and give rise to every other cell type in the body.
By defining the relationships between human skeletal stem cells and downstream skeletal progenitors, the researchers also created a detailed lineage map of stem-cell-mediated formation of skeletal tissues in humans.