Effects of cells of epithelial rests of Malassez and endothelial cells on synthesis of glycosaminoglycans by periodontal ligament fibroblasts in vitro
Merrilees, M.J.; Sodek, J.; Aubin, J.E.
Developmental Biology 97(1): 146-153
ISSN/ISBN: 0012-1606 PMID: 6404673 DOI: 10.1016/0012-1606(83)90072-6
Cultures of fibroblast-like cells (PLF) and epithelial rest cells (PLE) prepared from explants of porcine periodontal ligament synthesized and secreted 4 glycosaminoglycans (GAG) in differing proportions. The PLF produced predominantly chondroitin sulfate (> 60%) with smaller amounts of hyaluronic acid (HA) (17%), dermatan sulfate (13%) and heparan sulfate (7%), whereas PLE produced predominantly HA (> 80%). In coculture and under conditions of reciprocal transfer of conditioned media neither cell type affected the other's GAG synthesis. Endothelial cells (EC), however or their conditioned growth media, were able to stimulate increased GAG synthesis, especially HA, in PLF. A similar result was obtained with smooth muscle cells (SMC) cultured in ECM growth media, but here again PLE were unable to stimulate GAG synthesis by SMC. The spectrum of GAG found in whole ligament probably results both from independent production by, and from interaction between, the different cell types within the ligament. The results also provide support for a general hypothesis that loose connective tissues, which are rich in HA, are formed and maintained under the influence of epithelial, including endothelial, cells.