Effect of local injections of mesenchymal stem cells or osteoblasts on bone regeneration

Author(s)

Gileade Pereira Freitas

• Document type: Doctoral Thesis
• Press: Ribeirão Preto.
• Institution: Universidade de São Paulo (USP). Faculdade de Odontologia de Ribeirão Preto (PCARP/BC)
• Defense date: 2019-01-18

Examining board members

Adalberto Luiz Rosa; Leonardo Perez Faverani; Tarcilia Aparecida da Silva; Eduardo Hochuli Vieira

• Advisor: Adalberto Luiz Rosa

Abstract

Bone is a tissue with great capacity for regeneration, but in some situations, the extent of injury prevents tissue repair. In this scenario, cell therapy has attracted the attention of several research groups. However, many experimental aspects need to be better investigated to make this therapy an effective treatment for the regeneration of defects in bone tissue. Therefore, the aim of this study was to evaluate the potential of mesenchymal stem cells (MSCs) derived from bone marrow (BM-MSCs) and adipose tissue (AT-MSCs), as well as osteoblasts (OBs), differentiated from these MSCs (BM-OBs and AT-OBs) to regenerate bone tissue when injected directly into defects of 5mm diameter created in calvaria of rats. For this, MSCs were obtained from bone marrow of femur and inguinal adipose tissue of rats, expanded in vitro and maintained with characteristics of MSCs or differentiated in OBs. The MSCs were characterized by immunophenotyping for markers CD29, CD31, CD34, CD45 and CD90 by flow cytometry. Osteoblastic differentiation was confirmed by the evaluation of the gene expression of runtrelated transcription factor 2 (Runx2), alkaline phosphatase (Alp) and osteopontin (Opn) by real-time PCR. Two weeks after the creation of the bone defects, the injections of the cells were performed. The viability of the cells after their passage through the 21 gauge (21G) needle used in the injections was evaluated. The cell tracking in bone defects was evaluated by bioluminescence using an injection of BM-MSCs, AT-MSCs, BM-OBs and AT-OBs expressing luciferase. Four weeks after the injections, the animals were killed, and the bone tissue formed was evaluated by computerized microtomography, histological analysis, nanoindentation analysis and real-time PCR. Data were submitted to the normal curve test to determine the appropriate statistical test. The level of significance was 5% (p 0.05). It was observed that cell therapy with BM-MSCs, AT-MSCs, BM-OBs or AT-OBs was effective in injecting viable cells, which remained at the site of the bone defect and induced greater bone formation compared to defects that did not receive cells. There was no difference in bone tissue induced by either BM-MSCs or AT-MSCs or in that induced by BM-OBs or AT-OBs. Although some marked differences in molecular signatures, BM-MSCs, AT-MSCs, BM-OBs and AT-OBs were able to form bone tissue with the same mechanical properties of existing bone tissue in calvaria (AU)

• FAPESP's process: 14/26864-4 - Effect of Local Injections of Mesenchymal Stem Cells and Osteoblasts on Bone Regeneration
• Grantee: Gileade Pereira Freitas
• Support Opportunities: Scholarships in Brazil - Doctorate