Advances in Bone Tissue Engineering to Increase the Feasibility of Engineered Implant

IntroductIon Millions of patients experience bone loss as a result of degenerative disease, trauma, or surgery (Xu, Othman, Hong, Peptan, & Magin, 2005). Healthy bone tissue constantly regenerates itself and remodels its architecture to meet the mechanical demands imposed on it, as described by Wolff's " Law of Bone Remodeling " (Wolff, 1986). However, this capacity is severely limited when there is insufficient blood supply, mechanical instability, or competition with highly proliferating tissues (Pinheiro & Gerbei, 2006). Furthermore, severe bone losses can be detrimental to individuals, because they reduce the bone's ability to remodel, repair, and regenerate itself (Luo et al., 2005; Nordin & Franklin, 2001), ultimately resulting in the deterioration of a patient's health, and, in some instances, death (Luo et al., 2005). Because the repercussions of bone loss are severe, it is important to replace lost bone in patients. The current gold standard for specific-site structural and functional bone defect repair is autologous bone grafts (Mauney, Volloch, & Kaplan, 2005) or autografts. While autografts do not present the problem of immune rejection , since the bone tissue is being transplanted from another region of the patient's own body (Rahaman & Mao, 2005), they present certain complications such as significant donor site morbidity (death of tissue remaining in the region from which the donor tissue was removed), infection, malformation, and subsequent loss of graft function (Mauney et al., 2005). Another established and widely employed technique for the treatment of bone loss is the transplantation of allograft bone or bone tissue from a donor (Mauney et al., 2005). Although allograft bone is effective in treating bone loss, there are several common problems associated with it: first, a compatible donor must be found (Jones, Erhenfried, & Hench, 2006) in order to minimize the possibility of immune rejection by the patient; second, there is a risk of potential disease transmission from the donor to the patient; third, donor site morbidity can occur (Jones et al., 2006); and, finally, there is a limited supply of donor tissue (Mauney et al., 2005). Therefore, patients often experience long waiting periods before receiving the transplant, due to the scarcity of tissue donors, and this can exacerbate bone tissue loss (Jones et al., 2006). The development of the field of bone tissue engineering has expanded the solutions available to the problem of bone tissue loss. Arguably, implants developed via tissue engineering applications may be a more viable …