The gums are also known as the gingivae, and this soft tissue serves as a biological barrier that covers the oral cavity of the maxillae and mandible (upper and lower jawbones). The gingivae also harbor a stem cell population known as gingival mesenchymal stem cells or GMSCs.
“Oh that’s a big surprise,” you say, “another mesenchymal stem cell population found in the body.” Well this one is a big deal because of its tissue of origin. Most MSCs are formed during embryonic development from cells that originate from the mesoderm, the embryonic tissue that lies between the skin of the embryo and the gut. Mesoderm forms the muscles, bones, connective tissue, adrenal glands, circulatory system, kidneys, gonads, and some other vitally important tissues.
However, in the head, a large number of tissues are formed from “neural crest cells.” Neural crest cells hail from the top of the neural tube, which is the beginnings of the spinal cord. The dorsal-most portion of the neural tube contains a population of cells that move out of the neural tube and colonize the embryo to form a whole host of tissues. These include: Neurons, including sensory ganglia, sympathetic and parasympathetic ganglia, and plexuses, Neuroglial cells, Schwann cells, Adrenal medulla, Calcitonin-secreting cells, Carotid body type I cells, Epidermal pigment cells, Facial cartilage and bone Facial and anterior ventral skull cartilage and bones, Corneal endothelium and stroma, Tooth papillae, Dermis, smooth muscle, and adipose tissue of skin of head and neck, Connective tissue of salivary, lachrymal, thymus, thyroid, and pituitary glands, Connective tissue and smooth muscle in arteries of aortic arch origin. Wow, that’s a lot of stuff. I think you can see that these neural crest cells are important players during embryonic development.
Songtao Shi, from the Ostrow School of Dentistry, University of Southern California and his co-workers demonstrated that approximately 90% of GMSCs are derived from cranial neural crest cells and 10% are derived from mesoderm. This is important because neural crest-based stem cells seem to have greater plasticity.
Shi and his team compared mesodermally derived MSCs with GMSCs and the neural crest derived MSCs have a greater ability to differentiate into neural cells and cartilage-making cells.
In a mouse model of colitis in which mice are fed dextran sulfate sodium, which induces colitis in the mice, the neural crest derived MSCs did a better job of relieving the inflammation associated with colitis than their mesodermally derived counterparts.
Shi admits that further research on these stem cells must be done in order to better understand them and their functional roles. Shi is especially interested in the functional interaction between the neural crest derived MSCs in the gum and the mesodermally derived MSCs. Also, their potential for suppressing inflammation in particular diseases of the immune system and wound healing needs to be examined in some detail.