GROWTH-FACTOR MODULATION OF MITOGENIC RESPONSES AND PROTEOGLYCAN SYNTHESIS BY HUMAN PERIODONTAL FIBROBLASTS

In order to understand the relationship between specific growth factor s and matrix synthesis by periodontal cells, we have investigated the effects of platelet-derived growth factor BE (PDGF-BB), insulin-like g rowth factor-I (IGF-1), and growth hormone on DNA and proteoglycan syn thesis by cultured human gingival and periodontal ligament fibroblasts in vitro. PDGF-BB and IGF-1, but not growth hormone, were mitogenic f or both periodontal ligament fibroblasts and gingival fibroblasts, alt hough the periodontal ligament cells responded more strongly. The mito genic response was accompanied by alterations in expression of matrix proteoglycan mRNA. For both the gingival and periodontal ligament cell s, there was a decrease in mRNA for decorin and an increase in mRNA fo r versican following exposure to IGF-1 and PDGF-BB. Although no change was seen in response to PDGF, biglycan mRNA level was increased by IG F-1 in periodontal ligament fibroblasts. With the gingival fibroblats, biglycan mRNA levels were unaffected by IGF-1, PDGF-BB, or growth hor mone. These findings suggest variable responses of fibroblasts to grow th factors depending upon anatomical site within the periodontium. Mor eover, there appears to be a correlation between cell proliferation an d the types of proteoglycan synthesised with decorin expression being suppressed, and versican being increased during fibroblast proliferati on. (C) 1998 Wiley-Liss, Inc.