FIGURE 1.

Schematic diagrams of the methods in this study. Passage 0 (P0) synovial mesenchymal stem cells (MSCs) were transplanted into the knees of 10 patients with degenerative meniscus injury. Synovial MSCs were additionally passaged up to P15. The chromosomal aneuploidy of MSCs at P0 to P15 was investigated by G‐banding and digital karyotyping using the DNA sequence. The safety of MSCs with trisomy 7 was tested by in vitro assays, in vivo transplantation, whole‐genome sequencing, and DNA methylation of P0 and P10 MSCs with/without trisomy 7. Blood and synovium were used as controls. MSCs with/without trisomy 7 were also analyzed for their gene expression profiles and chondrogenic potentials. Finally, the safety of the transplantation was evaluated after 5 years in 10 patients transplanted with MSCs with/without trisomy 7