Cementum attachment protein manifestation is restricted to the mineralized tissue forming cells of the periodontium.

The mechanisms that regulate cementogenesis are mainly unknown. A specific cementum attachment protein (CAP) has been recently partially characterized and found to be more efficient in supporting the attachment of alveolar bone cells (ABC) and periodontal ligament cells (PLC) than that of gingival fibroblasts (GF). The purpose of this study was to determine the capacity of human periodontal-derived cells to bind and express CAP and to relate these properties to their capacity to express alkaline phosphatase (AlP) and form mineralized tissue (MTF). ABC, PLC and GF were tested. Human stromal bone marrow cells (SBMC) and a cementoma-derived cell line (CC) served as controls. CAP binding was determined using 125I-CAP. The amount of MTF was assessed by alizarin red staining and image analysis determination of the amount of red-stained material. AlP and CAP expression were examined by histochemistry and immunochemistry, respectively. The highest expression of CAP was observed in CC, followed by PLC and ABC in decreasing order, whereas SBMC and GF did not express CAP. SBMC manifested the highest CAP binding capacity followed by CC, ABC, PLC and GF. MTF and AlP manifestation were greatest in SBMC, followed by ABC, PLC and CC. Collectively the results indicate that CAP binding and secretion are not linked and that CAP manifestation is restricted to periodontal derived cell lineages with the potential of forming mineralized tissues.