Abstract
The presence of mesenchymal progenitor cells (MPCs) in rheumatoid arthritis (RA) articular cartilage is sparsely investigated largely owing to the persistent pathogenic disease condition and lack of specific biomarkers. Considering the recent advancements for potential cell-based therapies in immunomodulatory diseases, such as RA, this in vitro study was aimed at investigating the cellular, molecular and differentiation characteristics of human RA cartilage-derived MPCs. Articular cartilage fragments from RA patients were obtained for the isolation and characterization of MPCs on their cellular and biological properties, cytogenic stability, pluripotency, and plasticity. Established MPCs were phenotypically identified using a panel of markers and their differentiation ability into mesenchymal lineages was assessed by cytochemical staining and the expression of molecular markers. MPCs displayed a heterogeneous population of cells with characteristic features of multipotent stem cells. Cells had higher viability, proliferative rate and colony-forming ability. Further, MPCs showed the expression of pluripotency markers, cytogenetic stability and minimal replicative senescence. In addition, MPCs differentiated into osteocytes, adipocytes and chondrocytes, and modulated the expression of each lineage-specific gene markers. The results demonstrated the availability of a viable pool of MPCs residing in RA cartilage, which could serve as an ideal cell source for reinstating native homotypic cartilage.