Tissue Engineering Construct for Articular Cartilage Restoration with Stromal Cells from Synovium vs. Dental Pulp—A Pre-Clinical Study

Background/Objectives: Cartilage injuries and osteoarthritis are prevalent public health problems, due to their disabling nature and economic impact. Mesenchymal stromal cells (MSCs) isolated from different tissues have the immunomodulatory capacity to regulate local joint environment. This translational study aims to compare cartilage restoration from MSCs from the synovial membrane (SM) and dental pulp (DP) by a tissue-engineered construct with Good Manufacturing Practices. Methods: A controlled experimental study was conducted on fourteen miniature pigs, using scaffold-free Tissue Engineering Constructs (TECs) from DP and SM MSCs, with a 6-month follow-up. Total thickness cartilage defects were created in both hind knees; one side was left untreated and the other received a TEC from either DP (n = 7) or SM (n = 7). An MRI assessed the morphology using the MOCART scoring system, T2 mapping evaluated water, and collagen fiber composition, and histological analysis was performed using the ICRS-2 score. Results: The untreated group had a mean MOCART value of 46.2 ± 13.4, while the SM-treated group was 65.7 ± 15.5 (p < 0.05) and the DP-treated group was 59.0 ± 7.9 (n.s.). The T2 mapping indicated a mean value of T2 of 54.9 ± 1.9 for native cartilage, with the untreated group at 50.9 ± 2.4 (p < 0.05). No difference was found between the T2 value of native cartilage and the treated groups. The ICRS-2 mean values were 42.1 ± 14.8 for the untreated group, 64.3 ± 19.0 for SM (p < 0.05), and 54.3 ± 12.2 for DP (n.s.). Conclusion: MRI and histological analysis indicated that TEC treatment led to superior cartilage coverage and quality compared to the defect group. TECs from SM demonstrated better results than the defect group in the histological assessment.