New Strategies in Cartilage Tissue Engineering for Osteoarthritic Patients: Infrapatellar Fat Pad as an Alternative Source of Progenitor Cells

Novel tissue engineering strategies have proposed the combined use of articular condrocytes (ACs) and mesenchymal stem cells (MSCs) for the treatment of chondral lesions to overcome limitations related to the reduced cellular yield and low chondrogenic potential of ACs derived from subjects affected by osteoarthritis (OA). The aim of this study was to evaluate the multidifferentiative ability of MSCs derived from the knee infrapatellar fat pad (IFP-MSCs) by determining their osteogenic, adipogenic and chondrogenic potential as well as performing pellet coculture experiments using IFP-MSCs and ACs derived from the same donor. IFP-MSCs showed a marked clonogenic ability and the typical surface markers pattern of MSCs and efficiently differentiated towards adipogenic and osteogenic lineages. No significant difference in chondrogenic potential was observed between IFP-MSCs and ACs from OA patients. In coculture experiments, histological analysis showed an increase in glycosamminoglycans production correlated to the percentage of ACs and a significant up-regulation of aggrecan gene expression was observed in pellets containing 25% and 50% ACs respect to 100% IFP-MSCs pellets. Our data demonstrate that IFP-MSCs possess a considerable multidifferentiative potential and may be a suitable candidate to be used alone or combined with ACs for cell-based chondral treatments.