In Vitro Effect of Transforming Growth Factor‐β on Adhesion Molecule Expression by Human Gingival Fibroblasts Cultured in the Presence of a Titanium Abutment

Background: There is little information in the literature on the structural basis mediating gingival cell adhesion to the surface of titanium abutments. We cultured gingival fibroblasts on a titanium abutment creating as closely as possible the in vivo state. We analyzed the constitutive and transforming growth factor (TGF) β‐induced expression of the adhesion molecules CD44, CD49b, CD49c, CD51, CD54, and CD61 and extracellular matrix (ECM) components fibronectin, laminin and collagen IV. Methods: Three totally edentulous patients underwent implant treatment to anchor the mandibular denture on 2 implants. Gingival mucosa cell specimens were collected from the mandible during the first surgical stage and the gingival fibroblast cultures were prepared. Cells were cultured for 48 hours with or without isoforms TGF‐β1, TGF‐β2, and TGF‐β3. The expression of adhesion molecules and ECM components was analyzed by immuno‐fluorescence staining and flow cytometry. Results: The addition of TGF‐β isoforms to the cell culture over the incubation period had little effect on cell growth rate, but significantly influenced cell orientation, which changed from a sun‐burst pattern in control conditions to a more elongated organization and perpendicular to abutment surface. In all fibroblast preparations, a marked expression of CD44 and a moderate positivity for anti‐CD49b and CD49c were found. By contrast, CD51, CD54, and CD61 expressions were negligable. When fibroblasts were cultured for 48 hours in the presence of TGF‐β, the expression of most of the receptor molecules increased. The cells expressed constitutively moderate levels of laminin and fibronectin and low amounts of collagen IV. By contrast, treatment with any one of the 3 TGF‐β isoforms greatly enhanced the expression levels of fibronectin, laminin, and, especially, collagen IV. Conclusions: TGF‐β not only seems to affect the orientation of the cultured gingival fibroblasts, but also to induce a clearcut modification of their adhesion molecule expression. J Periodontol 2001;72:1658‐1665.