BIODEGRADABLE SCAFFOLDS FOR BONE REGENERATION - Intelligent Scaffolds for Tissue Engineering and Regenerative Medicine - page 823

and antigens. 15 The self-assembled three-dimensional microenvi-
ronment structure is also similar to natural ECM, and PM may be
useable as a scaffold because of these nanoscale morphological
features that may help to control cell behavior. 13 - 16
Indeed, in our animal study, 13 PM and PM/dMSCs were
implanted into dog mandible bone defects. Macroscopic findings
showed that these scaffolds had almost completely disappeared
without infection after implantation. Implanted and nonimplanted
control regions were collected after two, four, and eight weeks
for histological examination. The cavities filled with PM/dMSCs
resulted in new bone formation, which was manifested in a tubular
pattern and by abundant vascularization after four weeks. The
control, PM, and PM/PRP groups did not exhibit appreciable
bone formation (Fig. 40.5). The bone-regenerating ability of all
implants was assessed by measuring the cortical and medullary
bone surface areas without native bone by image analysis. Adding
PM alone to the cavity did not significantly increase the cortical
or medullary bone surface area compared with the control at two,
four, and eight weeks. In contrast, the PM/dMSCs groups showed
a significant increase in the surface area at all three time points
compared with the control and PM groups at two, four, and eight
weeks. 13
However, the quality of PM needs to be improved because it is
too soft to keep the form of bone formation. Taken together, it is
suggestedthatPMmightbeusefulasascaffoldofboneregeneration
incelltherapy,andtheseresultswouldleadtoaneffectivetreatment
method for bonedefects.
40.2.3 Injectable Tissue-Engineered Bone
We have attempted to regenerate bone with TERM in a significant
osseous defect, more effective with minimal invasiveness and
good plasticity and nonimmunoreactive, and to provide a clinical
alternative to autogenous bone grafts. 17 - 20 In the study, we used
MSCsastheisolatedcellsandPRPasthegrowthfactorsandscaffold.
The new tissue-engineered technology we developed is called