Invasion of human cartilage by cultured multicellular spheroids of rheumatoid synovial cells--a novel in vitro model system for rheumatoid arthritis

Abstract

Objective: A new 3-dimensional cell culture system was established to examine the invasion of rheumatoid synovial cells into cartilage.

Methods: Synovial cells from 20 patients with rheumatoid arthritis (RA) and 15 patients with osteoarthritis (OA) were co-cultured as multicellular spheroids with cartilage fragments.

Results: After 4 weeks the rheumatoid spheroids eroded the cartilage. The destruction of cartilage was supported by a high expression level of cathepsin D and matrix metalloproteinases. In contrast, the OA tissue showed attachment to the cartilage only.

Conclusion: Our results indicate that spheroid/cartilage co-cultures seem to be a suitable in vitro model for the study of destructive cellular mechanisms that occur in RA.