Synovial-Derived Mesenchymal Stem Cells Encapsulated in Alginate Beads Provide Better Outcomes for Equine Tarsus Chondral Lesions

Author(s): Vitor Hugo Santos, Joa?o Pedro Hu?bbe Pfeifer, Gustavo Santos Rosa, Emanuel Vitor Pereira Apolonio, Mariana Correa Rossi, Carlos Eduardo Fonseca-Alves, Carlos Alberto Hussni, Celso Antonio Rodrigues, Marcos Jun Watanabe, Anna Paula Balesdent Barreira, Ana Liz Garcia Alves

Synovial membrane-derived mesenchymal stem cells (_SMMSCs) demonstrate high chondrogenic potential in joint injuries, but their early dispersion decreases their immunomodulatory and reparative properties. This study aimed to evaluate the effect of encapsulated _SMMSCs in alginate hydrogels on induced chondral lesions in horses. Lesions were surgically induced in the talus of fifteen horses treated with PBS, free or encapsulated _SMMSCs from an allogeneic cell bank. Clinical, orthopedic and synovial analyses were performed at baseline and on Days 1, 2, 4, 7 and 14 for cytological and biomarker analyses (IL-1, IL-6, IL-10, PGE2, TNF α, INF-γ, IGF, P Substance and SAA). At Day 150, cartilage biopsies were performed for macroscopic, histological and immunohistochemical analyses. The results were statistically significant when p ≤ 0.05. Lameness and articular distention were observed in all horses on Days 1 and 2. There was an increase in TNCC and neutrophil count at Day 1 in all groups, which was significantly higher in the encapsulated SMMSC group. This group also showed an earlier peak of macrophages and lymphocytes. There was no significant difference between groups on biomarker analysis but between time points for IL-1α, IL-6, INF-γ and SAA in the cell groups. The encapsulated _SMMSC group also presented significantly higher Global Repair Evaluation, histological and immunohistochemical scores. Therefore, _SMMSCs encapsulated in alginate beads presented immunomodulatory capacity, resulting in intensified and premature inflammatory reactions and better macro- and microscopic aspects of tissue repair than the other groups, providing better outcomes for equine tarsus chondral lesions.