RESUMO
The loss of cartilage tissue due to trauma, tumour surgery or congenital defects, such as microtia and anotia, is one of the major concerns in head and neck surgery. Recently tissue-engineering approaches, including gene delivery, have been proposed for the regeneration of cartilage tissue. In this study, primary chondrocytes were genetically modified with plasmid-encoding bone morphogenetic protein-7 (BMP-7) via the commercially available non-viral Turbofect vector, with the aim of bringing ex vivo transfected chondrocytes to resynthesize BMP-7 in vitro as they would in vivo. Genetically modified cells were implanted into gelatin-oxidized dextran scaffolds and cartilage tissue formation was investigated in 15 × 15 mm auricular cartilage defects in vivo in 48 New Zealand (NZ) white rabbits for 4 months. The results were evaluated via histology and early gene expression. Early gene expression results indicated a strong effect of exogenous BMP-7 on matrix synthesis and chondrocyte growth. In addition, histological analysis results exhibited significantly better cartilage healing with BMP-7-modified (transfected) cells than in the non-modified (non-transfected) group and as well as the control.
Assuntos
Proteína Morfogenética Óssea 7/farmacologia , Cartilagem Articular/patologia , Condrócitos/metabolismo , Criogéis/química , Alicerces Teciduais/química , Cicatrização/efeitos dos fármacos , Agrecanas/genética , Agrecanas/metabolismo , Animais , Proteína Morfogenética Óssea 7/genética , Proteína Morfogenética Óssea 7/metabolismo , Cartilagem Articular/efeitos dos fármacos , Células Cultivadas , Condrócitos/citologia , Condrócitos/efeitos dos fármacos , Colágeno Tipo I/genética , Colágeno Tipo I/metabolismo , Colágeno Tipo II/genética , Colágeno Tipo II/metabolismo , Regulação da Expressão Gênica/efeitos dos fármacos , Humanos , Masculino , Microscopia Eletrônica de Varredura , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Coelhos , Regeneração/efeitos dos fármacos , Regeneração/genética , Cicatrização/genéticaRESUMO
The aim of this study is to develop magnetically loaded nanosorbents carrying specific monoclonal antibodies (namely CD105 and CD73) for separation of mesenchymal stem cells from cell suspensions. Super-paramagnetic magnetite (Fe3O4) nanoparticles were produced and then coated with a polymer layer containing carboxylic acid functional groups (average diameter: 153 nm and polydispersity index: 0.229). In order to obtain the nanosorbents, the monoclonal antibodies were immobilized via these functional groups with quite high coupling efficiencies up to 80%. These nanosorbents and also a commercially available one (i.e., microbeads carrying CD105 antibodies from Miltenyi Biotec., Germany) were used for separation of CD105+ and CD73+ mesenchymal stem cells from model cell suspension composed of peripheral blood (97.6%), human bone marrow cells (1.2%) and fibroblastic cells (1.2%). The initial concentrations of the CD105+ and CD73+ cells in this suspension were measured as 5.86% and 6.56%, respectively. A flow-through separation system and a very simple homemade batch separator unit were used. We were able to increase the concentration of CD105+ cells up to about 86% in the flow-through separation system with the nanosorbents produced in this study, which was even significantly better than the commercial one. The separation efficiencies were also very high, especially for the CD73+ cells (reached to about 64%) with the very simple and inexpensive homemade batch unit.
