Biological activity of metallic wear particles and metal ions in vitro and in vivo

无菌性松动仍然是全关节置换术中翻修手术最常见的原因，主要是由组织对磨损颗粒的反应引起的。拟议的项目旨在确定在体外和体内，普通金属-金属或陶瓷-聚乙烯承载表面对髋关节内假体磨损颗粒的生物活性的差异。在磨损模拟器中产生了陶瓷-聚乙烯和金属-金属承载表面的磨损颗粒。根据产生的磨损颗粒（金属和聚乙烯磨损颗粒）的大小和形状参数进行分析和分类。在对附着的内毒素进行纯化和消除后，将产生的磨损颗粒（聚乙烯、金属和金属离子）与不同的人类细胞类型（单核细胞、巨噬细胞、成骨细胞）一起培养，并与腐蚀过程产生的金属离子进行比较。体外研究的重点是分析细胞和分子生物学效应，这取决于磨损颗粒的材料类型和形貌。应测定人原代成骨细胞和巨噬细胞与磨损颗粒接触后的活力和增殖，以及细胞凋亡或坏死的速率。此外，还将评估活化细胞因子的定量以及与颗粒接触后OPG和sRANKL的表达。在第二步中，磨料颗粒在建立的动物模型中消除粘附的脂多糖后使用。将颗粒注射到小鼠膝关节内，利用活体显微镜分析滑膜组织的全身炎症反应。此外，使用组织学调查和免疫组织化学评估局部和全身炎症反应，并与体外结果进行比较。因此，可以实现对应用磨损颗粒和金属离子的炎症反应的基本理解。由于迄今为止对磨损碎片的免疫反应的时间过程尚不清楚，在随后的项目期间，应评估各种磨损颗粒和金属离子在不同时间的生物活性。该项目的研究结果可用于制定预防颗粒引起的全关节置换术无菌性松动的新策略，例如材料和表面设计的新发展以及阻断炎症信号通路的医疗方法。

The aseptic loosening is still the most common reason for revision surgery in total joint arthroplasty and is mainly caused by a tissue response to wear particles. The proposed project seeks to determine a difference of the biologic activity to wear particles of hip endoprostheses between common metal-metal or ceramic-polyethylene bearing surfaces both in vitro and in vivo. For these experiments, wear particles of ceramic-polyethylene and metal-metal bearing surfaces are produced in a wear simulator. The generated wear particles (metal and polyethylene wear particles) are analyzed and categorized regarding size and shape parameters. After purification and elimination of adherent endotoxin, the generated wear particles (polyethylene, metal, and metal ions) are cultured with different human cell types (monocytes, macrophages, osteoblasts), comparing them with metal ions, as a result of corrosion processes.The focus of the in vitro studies is the analysis of cell and molecular biological effects depending on the material type and topography of the wear particles. The vitality and proliferation of human primary osteoblasts and macrophages, as well as the rate of apoptosis or necrosis, after contact with the wear particles should be determined. In addition, a quantification of activated cytokines and the expression of OPG and sRANKL after contact with the particles will be evaluated.In a second step, the abrasive particles are used after elimination of adherent lipopolysaccharides in an established animal model. The particles are injected into murine knee joints to analyze the systemic inflammatory reactions in the synovial tissue using intravital microscopy. In addition, the local and systemic inflammatory reactions are evaluated using histological investigations and immunohistochemistry, and compared to the in vitro results.Hence, a basic understanding of this inflammatory reaction to the applied wear particles and metal ions can be achieved. Since the time course of immune responses to the wear debris is unclear so far, in a subsequent project period the various wear particles and metal ions should be evaluated for their biological activity at different times.The project findings can be incorporated into the development of new strategies for the prevention of particle-induced aseptic loosening of total joint replacements such as new developments in material and surface design and medical treatment approaches for blocking inflammatory signal pathways.