GENE THERAPY FOR RECONSTRUCTING PERIODONTAL TISSUES

由于牙周病而丢失的组织，即，骨、牙骨质和功能性PDL可以使用现有的牙周治疗在一定程度上恢复。然而，结果往往是令人失望的，因此，有必要开发新的范例再生牙周组织。 细胞移植和基因转移的先进技术使我们能够提出关键问题，如在体外和体内调节牙周细胞的细胞和分子机制。这些问题的答案将导致用于再生牙周组织的改进策略。基于迄今为止的研究，我们假设编码血小板衍生生长因子（PDGF）和/或骨形态发生蛋白-7（BMP-7）的腺病毒构建体转染成牙骨质细胞，然后并入三维生物可降解聚合物用于临床应用，将改善再生治疗的结果。这一假设得到以下结果的支持：a）培养的成牙骨质细胞表达与促进牙骨质原位形成的类似细胞相关的基因，并且培养的成牙骨质细胞在7天内诱导矿物质结节形成; B）PDGF和BMP-7在体外增强牙周细胞功能，并在体内促进牙周再生;和c）可生物降解的聚合物允许监测因子向局部部位的释放，并且与体内伤口愈合相容。该假设将在三个具体目标下进行测试：1）确定编码BMP-7和PDGF的腺病毒构建体在体外转导到成牙骨质细胞中的效率; 2）建立用于促进体外牙骨质形成的适当环境;和3）证明成牙骨质细胞在体内再生牙骨质，并且此外，PDGF和/或BMP-7的表达增强再生。从这些研究中获得的知识将产生新的见解，利用基因治疗技术来恢复牙周组织以及其他矿物质相关组织。

Tissues lost as a consequence of periodontal disease, i.e., bone, cementum and a functional PDL, can be restored to some degree using existing periodontal therapies. Nevertheless, results are often disappointing and therefore, there is a need to develop new paradigms for regenerating periodontal tissues. Advanced technologies in cell transplantation and gene transfer enable us to ask critical questions as to the cellular and molecular mechanisms regulating periodontal cells both in vitro and in vivo. Answers to these questions will result in improved strategies for use in regenerating periodontal tissues. Based on studies to date we hypothesize that adenoviral constructs encoding either platelet-derived growth factor (PDGF) and/or bone morphogenetic protein-7 (BMP-7) transfected into cementoblasts and then incorporated into three dimensional biodegradable polymers for clinical application will improve outcomes of regenerative therapy. This hypothesis is supported by results indicating that: a) cultured cementoblasts express genes associated with comparable cells that promote cementum formation in situ, and that cultured cementoblasts induce mineral nodule formation within 7 days; b) PDGF and BMP-7 enhance periodontal cell function, in vitro and promote periodontal regeneration, in vivo; and c) biodegradable polymers allow for monitored release of factors to a local site and are compatible with wound healing, in vivo. This hypothesis will be tested under three specific aims: l) To determine transduction efficiency of adenoviral constructs, encoding BMP-7 and PDGF, into cementoblasts in vitro; 2) To establish the appropriate environment for promoting cementogenesis in vitro; and 3) To prove that cementoblasts regenerate cementum, in vivo and furthermore, that expression of PDGF and/or BMP-7 enhance regeneration. Knowledge gained from these studies will produce new insights into the use of gene therapy technologies to restore the periodontium as well as other mineral-associated tissues.