Ectopic bone formation during tissue-engineered cartilage repair using autologous chondrocytes and novel plasma-derived albumin scaffolds.

PURPOSE: The aims of this study were twofold: first, to evaluate the production of cartilaginous tissue in vitro and in vivo using a novel plasma-derived scaffold, and second, to test the repair of experimental defects made on ears of New Zealand rabbits (NZr) using this approach. MATERIALS AND METHODS: Scaffolds were seeded with chondrocytes and cultured in vitro for 3 months to check in vitro cartilage production. To evaluate in vivo cartilage production, a chondrocyte-seeded scaffold was transplanted subcutaneously to a nude mouse. To check in vivo repair, experimental defects made in the ears of five New Zealand rabbits (NZr) were filled with chondrocyte-seeded scaffolds. RESULTS: In vitro culture produced mature chondrocytes with no extracellular matrix (ECM). Histological examination of redifferentiated in vitro cultures showed differentiated chondrocytes adhered to scaffold pores. Subcutaneous transplantation of these constructs to a nude mouse produced cartilage, confirmed by histological study. Experimental cartilage repair in five NZr showed cartilaginous tissue repairing the defects, mixed with calcified areas of bone formation. CONCLUSION: It is possible to produce cartilaginous tissue in vivo and to repair experimental auricular defects by means of chondrocyte cultures and the novel plasma-derived scaffold. Further studies are needed to determine the significance of bone formation in the samples.

Regeneration of mandibular defects using adipose tissue mesenchymal stromal cells in combination with human serum-derived scaffolds.

Bone regeneration is a challenging issue. Traditional solutions bring risks, potential complications, and morbidity. The aim of the present study was to regenerate critical-sized mandible defects in athymic rats with adipose tissue mesenchymal stromal cells (AT-MSCs) in combination with human serum-derived scaffolds. Two approaches to treatment were performed. The first approach used differentiated stromal cells that became osteogenic cell lines. The second approach used no pre-differentiation. Follow-up periods were 45 days and 90 days. Both cell types were combined with human serum-derived scaffolds. Afterward, histological (haematoxylin-eosin and Masson's Trichrome stain modified by Goldner), immunohistochemical (human vimentin and Stro-1), and radiological (microCT) studies were performed. The level of calcification between the groups was compared by analysis of variance, and statistical significance was set at p < 0.05. The results demonstrate that bone regeneration can be achieved with both undifferentiated and pre-differentiated cells, but that the structure and level of calcification were better achieved with pre-differentiated cells (p < 0.05). The scaffold is suitable for this cell type, is osteoconductive and simple to perform. This article highlights the possible application of adipose tissue mesenchymal stromal cells in combination with a non-mineralized scaffold in bone regeneration.