The effect of bone allografts combined with bone marrow stromal cells on the healing of segmental bone defects in a sheep model

Abstract

BackgroundThe repair of large bone defects is a major orthopedic challenge because autologous bone grafts are not available in large amounts and because harvesting is often associated with donor-site morbidity. Considering that bone marrow stromal cells (BMSC) are responsible for the maintenance of bone turnover throughout life, we investigated bone repair at a site of a critically sized segmental defect in sheep tibia treated with BMSCs loaded onto allografts. The defect was created in the mid-portion of the tibial diaphysis of eight adult sheep, and the sheep were treated with ex-vivo expanded autologous BMSCs isolated from marrow aspirates and loaded onto cortical allografts (n = 4). The treated sheep were compared with control sheep that had been treated with cell-free allografts (n = 4) obtained from donors of the same breed as the receptor sheep.ResultsThe healing response was monitored by radiographs monthly and by computed tomography and histology at six, ten, fourteen, and eighteen weeks after surgery. For the cell-loaded allografts, union was established more rapidly at the interface between the host bone and the allograft, and the healing process was more conspicuous. Remodeling of the allograft was complete at 18 weeks in the cell-treated animals. Histologically, the marrow cavity was reestablished, with intertrabecular spaces being filled with adipose marrow and with evidence of focal hematopoiesis.ConclusionsAllografts cellularized with AOCs (allografts of osteoprogenitor cells) can generate great clinical outcomes to noncellularized allografts to consolidate, reshape, structurally and morphologically reconstruct bone and bone marrow in a relatively short period of time. These features make this strategy very attractive for clinical use in orthopedic bioengineering.

Aspecto radiológico e macroscópico de matriz óssea mineralizada heteróloga fragmentada e polimetilmetacrilato autoclavados em falha óssea de tíbia de coelho

“…2006, Turrer & Ferreira 2008, Spadeto Jr et al 2011, Freitas et al 2012, Fernandes et al 2014, demostrou pouca atividade óssea, quando comparados aos do pós-operatório imediato (Fig.1A,B). Provavelmente, esse período não seja suficiente para que ocorra deposição de tecido ósseo local.…”

Novel standardized massive bone defect model in rats employing an internal eight‐hole stainless steel plate for bone tissue engineering

“…Bone defects, especially critical size defects, have always been a complex problem in orthopaedics (Li et al, ). The high incidence of such injuries results in a high fracture non‐union rate, and this problem has attracted the attention of orthopaedic researchers (Fernandes et al, ). Currently, large segmental bone defects can be treated in the clinic by autogenous bone graft, allogeneic bone graft, transplantation with artificial bone, or nanometer artificial bone (Lin et al, ).…”

Neoformação óssea e osteointegração de biomateriais micro e nanoestruturados em ovinos

“…A escolha pela tíbia foi devido ao fato de esta ser um osso longo e de fácil acesso, comumente utilizado para experimentação de procedimentos ortopédicos em ovinos (Dias et al 2007, Silva 2011, Fernandes et al 2014, bem como em coelhos (Freitas et al 2013, Moreira et al 2014.…”

“…Fernandes et al (2014), investigaram os efeitos da adição de células osteoprogenitoras em aloenxertos (fragmentos ósseos obtidos de animais diferentes dentro da mesma espécie) conservados em glicerina 98%, e observaram uma rápida reconstrução óssea, estrutural e morfológica, principalmente pela alta capacidade osteoindutora destas células. Esta se mostrou uma importante ferramenta na correção de grandes defeitos ósseos.…”