Efficiency of Human Epiphyseal Chondrocytes with Differential Replication Numbers for Cellular Therapy Products

Figure 4

Long-term observation at the P0 (PDL 7) cell-implanted sites. P0 (HEC #6) cell-implanted sites were analyzed at 20 weeks (a–g) and 40 weeks (h–q). Macroscopic examination of the P0 cell-nodules (606 mg in weight) at 20 weeks showed smooth and whitish surface with focal reddish portion and vascular networks (a). Microscopic examination showed progress of enchondral ossification (b) with new bone formation and poor marrow cavity (c). Marrow cavity consisted of osteoblasts, osteoclasts, undifferentiated mesenchyme cells, and a few of immature adipocytes (d). Cartilage and core of the enchondral ossification were positive for COL II (e). Perichondrium, bone, and osteoid were positive for COL I (f). Endothelium in the early marrow cavity was positive for CD31 (g). Macroscopic examination of the P0 cell-nodules (686 mg in weight) at 40 weeks showed increased reddish portion with prominent vascular networks on the surface (h). Bone marrow cavity was surrounded by the cartilage and bone (i), which morphologically resembled to articular cartilage (j) and cortical bone (k), respectively. Trabecular bone was extended with the fatty marrow (l). Peripheral cartilage (m) and core of the enchondral ossification (n) were positive for COL II. Perichondrium, periosteum (o), and trabecular bones (p) were positive for COL I. The vessels in the bone marrow cavity were positive for CD31 (q).