Autor(es):
Gardel, Leandro S. 
; Serra, L. A. ; Reis, R. L. ; Gomes, Manuela E.
Data: 2013
Identificador Persistente: http://hdl.handle.net/1822/27017
Origem: RepositóriUM - Universidade do Minho
Assunto(s): Bone tissue engineering; Large animal models; Perfusion Bioreactors
Descrição
Tissue engineering and regenerative medicine (TERM) strategies for generation of new bone tissue includes the
combined use of autologous or heterologous mesenchymal stem cells (MSC) and three-dimensional (3D) scaffold
materials serving as structural support for the cells, that develop into tissue-like substitutes under appropriate
in vitro culture conditions. This approach is very important due to the limitations and risks associated with
autologous, as well as allogenic bone grafiting procedures currently used. However, the cultivation of osteoprogenitor
cells in 3D scaffolds presents several challenges, such as the efficient transport of nutrient and oxygen
and removal of waste products from the cells in the interior of the scaffold. In this context, perfusion bioreactor
systems are key components for bone TERM, as many recent studies have shown that such systems can provide
dynamic environments with enhanced diffusion of nutrients and therefore, perfusion can be used to generate
grafts of clinically relevant sizes and shapes. Nevertheless, to determine whether a developed tissue-like substitute
conforms to the requirements of biocompatibility, mechanical stability and safety, it must undergo
rigorous testing both in vitro and in vivo. Results from in vitro studies can be difficult to extrapolate to the in vivo
situation, and for this reason, the use of animal models is often an essential step in the testing of orthopedic
implants before clinical use in humans. This review provides an overview of the concepts, advantages, and
challenges associated with different types of perfusion bioreactor systems, particularly focusing on systems that
may enable the generation of critical size tissue engineered constructs. Furthermore, this review discusses some
of the most frequently used animal models, such as sheep and goats, to study the in vivo functionality of bone
implant materials, in critical size defects.
