Among the various types of stem cells, mesenchymal stem cells (MSCs) emerge promising in treating many diseases given their widespread occurrence and ability to differentiate into cells of the ectoderm, mesoderm and endoderm. Among the various sites from which they have been isolated, the teeth show the presence of stem cell populations whose properties are at par with that of bone marrow-derived mesenchymal stem cells. These cells are dental MSCs.
There are 2 layers in a tooth: an outer layer of enamel and an inner layer of dentine within which is the soft inner fibroblast pulp tissue. The dental MSCs are involved in the repair of teeth and their homeostasis. The cells are active for life to generate cells called odontoblasts in the pulp that function to repair damaged dentine.
On the basis of the origin, the naming of dental MSCs is done. For example, the inner tooth pulp of adult molars yield dental pulp stem cells (DPSCs), stem cells from human exfoliated deciduous teeth (SHED), periodontal ligament stem cells (PDLSCs) and even mesenchymal stem cells from the oral mucosa gingival that are discarded during teeth procedures. Research published in Stem Cells International in 2016 by scientists Ledesma-Martínez and team suggested that both DPSCs and SHEDs show similar properties and transplantation effects.
Looking at the applications of these cells, one evident one that emerges is to use cultured DPSC in the restoration of pulp after root canal treatment. While current approaches involve the use of cement for the refilling of the root canals, they do not restore the vitality of the tooth or the tissue. For example, Misako Nakashima is looking at the use of autologous dental pulp stem cells in patients with pulpitis. 25 weeks post-application of the stem cells, restoration of the pulp tissue with no adverse effects has been reported.
In another interesting article, Hox genes that form specific skeletal structures are expressed in the neural crest cells but are not expressed in the cranial neural crest cells that form the face and jaw skeleton. Hox-negative jaw progenitor cells expressed a Hox gene when implanted in the tibia to form bone thus, suggesting the use of these dental MSCs in craniofacial repair (Leucht et al, 2008). In another article published in 2014 in Neuroscience, Bray and colleagues reported that retinal signals could elicit responses from DPSCs in terms of expressing photoreceptor markers such as rhodopsin showing the potential of using these cells to treat blindness due to damaged photoreceptor function.
These varied reports from across the world show the potential of using dental mesenchymal stem cells. The cells are thus assets in a research lab looking at regenerative medicine.
Paul T. Sharpe. Dental mesenchymal stem cells. Development 2016 143: 2273- 2280.
Edgar Ledesma-Martínez, Víctor Manuel Mendoza-Núñez, and Edelmiro Santiago-Osorio. Mesenchymal Stem Cells Derived from Dental Pulp: A Review. Stem Cells International 2016 ;Article ID 4709572 .12 pages.
Nakashima, M. and Iohara, K (2014) Mobilized dental pulp stem cells for pulp regeneration: initiation of clinical trial. Journal of Endodontics. 40 Suppl, S26-S32.
Leucht, P, Kim, J.B, Amasha, R, et al (2008). Embryonic origin and Hox status determine progenitor cell fate during adult bone regeneration. Development 135, 2845-2854. doi:10.1242/dev.023788
- F. Bray, R. R. Cevallos, K. Gazarian, and M. Lamas, “Human dental pulp stem cells respond to cues from the rat retina and differentiate to express the retinal neuronal marker rhodopsin,” Neuroscience, vol. 280, pp. 142–155, 2014.