Researchers at the University of Pennsylvania School of Medicine have isolated a new source of adult stem cells that appear to have the potential to differentiate into several cell types.
If their approach to growing these cells can be scaled up and proves to be safe and effective in animal and human studies, it could one day provide the tissue needed by an individual for treating a host of disorders, including peripheral nerve disease, Parkinson's disease, and spinal cord injury.
"We are very excited about this new source of adult stem cells that has the potential for a variety of applications," says senior author Xiaowei (George) Xu, MD, PhD, Assistant Professor of Pathology. "A number of reports have pointed to the fact that adult stem cells may be more flexible in what they become than previously thought, so we decided to look in the hair follicle bulge, a niche for these cells." Xu and colleagues report their findings in the latest issue of the American Journal of Pathology.
Hair follicles are well known to be a source for adult stem cells. Using human embryonic stem cell culture conditions, the researchers isolated and grew a new type of multipotent adult stem cell from scalp tissue obtained from the National Institute of Health's Cooperative Human Tissue Network.
The mutipotent stem cells grow as masses the investigators call hair spheres. After growing the "raw" cells from the hair spheres in different types of growth factors, the investigators were able to differentiate the stem cells into multiple lineages, including nerve cells, smooth muscle cells, and melanocytes (skin pigment cells).
The differentiated cells acquired lineage-specific markers and demonstrated appropriate functions in tissue culture, according to each cell type. For example, after 14 days, 20% to 40% of the cells in the melanocyte media took on a weblike shape typical of melanocytes. The new cells also expressed biomarkers typical of pigment cells and when placed in an artificial human skin construct, produced melanin and responded to chemical cues from normal epidermis skin cells.