Biomedical Engineering Reference
In-Depth Information
differentiation [
93
]; FGF-2 promotes cell proliferation as well as chondrogenic
differentiation [
94
]; and IGF-I which has an anabolic effect on cartilage matrix
synthesis [
95
].
7.8 Part III: MSC-Based Treatment of Bone and Cartilage
Defects
To accomplish regeneration, on some occasions MSCs are applied without any
biomaterial, for example, in OI or in cartilage resurfacing of the osteoarthritic
joint. In most regeneration strategies, i.e., in the reconstruction of large bone and
cartilage defects, MSCs are usually transplanted in combination with scaffolds or
growth factors. For the purpose of regeneration, MSCs can be present either in an
undifferentiated or differentiated state. Following, some examples of the applica-
tion of MSCs in the regeneration of bone and cartilage defects will be discussed.
7.9 Bone Regeneration
7.9.1 Large Bone Defects
Large bone defects, also known as critical-sized bone defects, are one of the
problems in the field of regenerative medicine. Many attempts have, thus far, been
made to efficiently improve regeneration of tissue defects using MSCs. In this
context, the groundbreaking investigation by Bruder et al. has involved the
reconstruction of segmental bone defects (21 mm) in a canine femur [
96
]. In
clinical trials, the pioneers could be regarded as Quatro et al. who have reported
successful repairs of massive 4-8 cm defects in four human cases, aged
16-41 years. These authors have seeded MSCs on porous HA ceramic scaffolds
and transplanted them into the defects. Good integration of the implant with host
bone has led to recovery of limb function in all cases. A limitation associated with
human studies has been the inability of the researchers to perform histological
studies of the repair tissue [
97
]. Morishita et al. have reported results from three
patients with benign bone tumors who were treated with MSC transplantation.
According to their study, MSCs were first seeded on porous HA ceramics and
differentiated into bone cells prior to transplantation into the bone cavities that
were left after removal of the tumors [
98
].
In the MSC-based bone reconstruction field, the study by Gronthose et al. is
interesting. These researchers have attempted to reconstruct the mandible of a
56-year-old man who underwent an ablative tumor surgery 8 years prior, by
removing a large portion of his mandible (a length of 7 cm from the left para-
median region to the right retromolar region). In this study, the scaffold was
