Molecular Characterization and Differentiation of Mesenchymal Progenitor Cells from Human Rheumatoid Arthritis Cartilage.

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 of MPCs and characterization of their cellular and biological properties, cytogenetic 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 heterogenous 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.

Microbial Sterility Testing for Mesenchymal Progenitor Cells Derived from Human Osteoarthritis and Rheumatoid Arthritis Cartilage.

BACKGROUND: The goal is to evaluate the microbial sterility of mesenchymal progenitor cells (MPCs)-derived from osteoarthritis (OA) and rheumatoid arthritis (RA) articular cartilages. METHODS: Contaminants, including bacteria and fungi in MPC cultures were initially evaluated by inoculation culture methods and then affirmed through the amplification of 16S ribosomal DNA (rDNA) and internally transcribed spacer (ITS) regions, respectively, using polymerase chain reaction (PCR). Further, the mollicutes, if any, were identified by genus-specific 16S rDNA, and the positive samples were reamplified using species-specific primers. RESULTS: No bacteria or fungi were found to be compromising the sterility of MPCs (n = 20) assessed by both traditional culture methods and PCR. However, two in early passages and three in later passages of MPCs had the presence of mollicutes. Further rescreening for species of mollicutes indicated the presence of Mycoplasma hyorhinis, M. salivarium, and M. arginine. CONCLUSIONS: The PCR methods employed in this study could be beneficial as a rapid sterility testing of cell lines.