Modulacija morfologije osteogenih stanica pomoću ECM liganada i derivata caklinskog matriksa Modulation of Osteogenic Cell Morphology by ECM Ligands and Enamel Matrix Derivative

Introduction Successful regeneration of intra-oral osseous and periodontal defects requires adequate host tissue reactions with recruitment and subsequent activation (and protection) of relevant adjacent cell populations. Indispensable for the formation of new mineralised bony tissue and re-organisation of tooth supporting structures are osteogenic cells (1). In this context, fundamental therapeutic strategies in the field of 'guided tissue regeneration' (GTR) have been introduced (2-5). However, in case of utilisa-tion of alloplastic biomaterials like occlusive membranes or bone substitute materials, the applied materials have to meet stringent requirements, first of all biocompatibility. Furthermore, some kind of bio-activation with promotion of cell maturation is desirable. Insufficient tissue integration and/or bacterial colonisation of the alloplastic materials have been identified as potential risk factors for GTR (6). Prerequisite for tissue regeneration are well-balanced cell to extracellular matrix (ECM) interactions. In bony tissue, the composition of the ECM plays a regulatory role for osteogenic cell functions like adhesion, motility, proliferation and differentiation (7-9). Besides the ubiquitous protein collagen, laminins as components of the basement membrane play an additional important role in bone healing (1, 8, 10, 11). While the use of purified growth factors like bone morphogenetic proteins has not been established in daily routine periodontal therapy, the application of enamel matrix derivative (EMD) is an evidence-based therapeutic option (4, 12-18). The biological active ingredients identified in enamel matrix consist of a variety of specific matrix proteins like ame-logenin, tuftelin, ameloblastin and enamelin as well as proteases, contributing a pivotal role in the development of teeth and supporting structures (19-23). The only EMD currently commercially available is the porcine derived Emdogain® (Straumann, Switzerland). Emdogain® represents an acidic extract of porcine enamel matrix and contains mainly the amelogenin fraction. A positive long term effect on bony defects, probing depth and attachment level could be documented both clinically or radiograph-ically after application of these biomimetric active proteins (4, 14, 18, 24). In animal models, an improvement of periodontal regeneration, osteogene-sis and angiogenesis has been observed (25, 26). On a cellular and molecular level, a recent systematic review summarises effects of EMD on: (1) cell attachment , spreading, and chemotaxis; (2) cell prolif