2.2. Mesenchymal Stem Cells Derived from Human Bone Marrow

Human bone marrow-derived MSCs (Catholic MASTER Cells) were obtained from the Catholic Institute of Cell Therapy (CIC, Seoul, Korea). The Catholic MASTER Cells were allogeneic MSCs certified by the KFDA. The cells were obtained by human bone marrow aspiration from the iliac crest of healthy donors between the ages of 20 and 55 years. The process was approved by the Institutional Review Board of Seoul St. Mary's Hospital (approval numbers KIRB-00344-009 and KIRB-00362-006). Bone marrow aspirated from the donor was collected and sent to the CIC under good manufacturing practice (GMP) conditions. The CIC was responsible for the isolation, expansion, and quality control of allogeneic MSCs. Detailed information on the Catholic MASTER Cells was reported in a previous study [20]. Briefly, under conditions of bacterial sterility, mycoplasma sterility, and a low endotoxin level (<3 EU/mL) in the GMP-compliant facility, cells were expanded and tested for multilineage differentiation and cell-surface antigens.