Figure 3.

Three-dimensional (3D) in vitro pannus model for rheumatoid arthritis. During rheumatoid arthritis (RA), formation of an invasive pannus tissue in the synovial joints occurs. The pannus tissue ultimately leads to erosion of the underlying cartilage and even bone. Key players in pannus formation are the RA synovial fibroblasts (RASFs), showing an aggressive invasive behavior. For simulation of RA in the 3D in vitro pannus model, human chondrocytes are harvested from healthy donors and cultured for 2 weeks as high-density micromasses in 96-well plates. During this period, cartilage matrix formation occurs. Subsequently, micromasses are coated with human RASFs. After 14 days of coculture allowing intensive interactions of both cell types, the model can be used for the high-throughput screening of antirheumatic drugs. For automation, the CyBi™-Disk workstation (CyBio Inc., Jena, Germany) for parallel liquid handling is used.