Mesenchymal stem cells, or cells resembling these cells, have been found in a variety of different tissues in addition to the bone marrow. These include, fat, menstrual blood and teeth. One interesting question is how these cells differ from each other.
In a recent paper, (Wada et al. Immunomodulatory properties of human periodontal ligament stem cells. J Cell Physiol 2009 Jan 21) the immune modulatory activities of mesenchymal stem cells derived from the periodontal ligament were analyzed. For those of you like me, who don't know what the periodontal ligament is, I found a picture that I pasted below.
The authors found that mesenchymals from the periodontal ligament have a similar phenotype and differentiation ability as mesenchymals from the dental pulp and from the bone marrow. All of these cells were capable of inhibiting proliferation of human mononuclear cells stimulated non-specifically. Inhibition was also observed by gingival fibroblasts.
Suppression of immune cell proliferation was mediated by soluble factors, and more interestingly, suppressive conditioned media could be obtained by treating all of the cells with interferon gamma.
Mechanistically the authors suggest that TGF-beta, HGF, and IDO are all stimulated as a result of the interaction between the MSC and lymphocytes.
Image Source: www.studiodentaire.com