Effect of serum-derived albumin scaffold and canine adipose tissue-derived mesenchymal stem cells on osteogenesis in canine segmental bone defect model

Composite biological and synthetic grafts with progenitor cells offer an alternative approach to auto-or allografts for fracture repair. This study was conducted to evaluate osteogenesis of autologous serum-derived albumin (ASA) scaffolds seeded with canine adipose tissue-derived mesenchymal stem cells (Ad-MSCs) in a canine segmental bone defect model. ASA scaffold was prepared with canine serum using cross-linking and freeze-drying procedures. Beta-tricalcium phosphate (beta-TCP) was mixed at the cross-linking stage. Ad-MSCs were seeded into the scaffold and incubated for one day before implantation. After 16 weeks, the grafts were harvested for histological analysis. The dogs were divided into five groups: control, ASA scaffolds with and without Ad-MSCs, and ASA scaffolds including beta-TCP with and without Ad-MSCs. ASA scaffolds with Ad-MSCs had a significantly larger area of increased opacity at the proximal and distal host cortex-implant interfaces in radiographs 16 weeks after implantation compared to the groups with beta-TCP (p < 0.05). Histomorphometric analysis showed that ASA scaffolds with Ad-MSCs had significantly greater new bone formation than other gimps (p < 0.05). These results suggest that Ad-MSCs seeded into ASA scaffolds enhanced osteogenesis in the bone defect model, but that beta-TCP in the ASA scaffold might prevent penetration of the cells required for bone healing.