Stem Cells From Tooth Promote the Formation of Neural Cells

Stem Cells, August 7, 2008

Mesenchymal stem cells (MSCs) have already been known to differentiate into neural tissue, but usually the MSCs are extracted from bone marrow, peripheral blood, umbilical cord blood, or even, most recently, menstrual blood. MSCs have also been discovered in unexpected places, such as the eye. Now, however, stem cells with properties that are similar to MSCs have been extracted from dental pulp.

Researchers in Kaohsiung, Taiwan, in collaboration with scientists in the U.S., have used stromal cells derived from the dental pulp of Rhesus macaque monkeys to promote the formation of neural cells in mice. The DPSCs (dental pulp stem/stromal cells), which were extracted from the teeth of the monkeys, were found to be similar in their properties and behavior to MSCs that are derived from human bone marrow. Led by Dr. Anderson Hsien-Cheng Huang, of the Department of Oral Pathology at the Grace Dental Clinic at the School of Dentistry at Kaohsiung Medical University Hospital in Kaohsiung, Taiwan, a team of scientists implanted undifferentiated, untreated DPSCs into the hippocampus of mice, where the cells were found to stimulate the differentiation of pre-existing endogenous neural progenitor cells, as well as the recruitment of mature neurons to the site of the graft. According to the authors of the study, "Although the DPSC graft itself was short-term, it had long-term effects by promoting growth factor signaling." Such growth factor signaling, which is a result of the high concentration of neurotrophic growth factors that the DPSCs released, plays a major role in the modulation of the neurophysiological microenvironment, which in turn is what directs the transformation of endogenous stem and progenitor cells into neural tissue.

The ability of stem cells that are derived from dental pulp to promote the proliferation and differentiation of neurological tissue should come as no surprise, since dental pulp is composed of odontoblast cells which originate in the neural crest during embryological development. A natural "affinity", or tendency toward a specific type of differentiation, therefore exists between DPSCs and neural tissue.

Dr. Huang and his colleagues hope that the therapeutic properties of something as common as dental pulp, which is usually discarded in childhood, might allow for greater ease in the development of personalized stem cell therapies which could be custom tailored to the individual patient, using his or her own dental pulp.