Maxillofacial Bone Regeneration Using Tissue Engineering Concepts - Engineered Bone: Tissue Engineering Intelligence Unit - page 187

Stem Cell
Stem cells create or recreate functional structures using information and signaling which
have been preprogrammed. As we understand these programs and behaviors, we can use them
to our advantage in the rational design of living tissues. The source of cells for creation of these
structures is a major challenge. Much is known about stem cells and cell lineages in the bone
marrow and blood. Recently, mesenchymal stem cells (MSCs) have received widespread atten-
tion because of their potential utility in tissue engineering applications. 8 After expansion to the
appropriate cell number, the cells can then be transferred to templates where further remodel-
ing can occur. It was reported that MSCs derived from bone marrow have osteochondral dif-
ferentiation potential in vitro 9,10 and in vivo, 11,12 and therefore, may play an important role in
the repair of bone defects.
Mesenchymal Stem Cells and Biodegradable Ceramics
We prepared to apply a biodegradable scaffold, pure β -TCP, especially synthesized by a wet
milling method (mechanochemical method), which was an excellent material that induced
bone formation, while gradually being degraded and was finally replaced by new bone. It was
reported that β -TCP with a three-dimensional structure provided an excellent environment
for bone regeneration and its surface facilitated cell attachment, proliferation, and osteogenic
differentiation. We investigated whether β -TCP loaded with MSCs had an osteogenic poten-
tial at an ectopic site. 13
Animal Experiments
The β -TCP was supplied by NGK SPARK PLUG CO., LTD., Nagoya, Japan. The solid and
porous components of the microstructure were completely interconnected. The pore average was
200-400 µ m in diameter, the interconnection average was 60 µ m and the average void volume
was 90%. These ceramics were a disc-shaped, 5 mm in diameter and 4 mm in thickness (Fig. 6).
For MSCs isolation and culture expansion male 7-week-old Fisher F344 rats were sacrificed
by pentobarbital overdose. Both ends of the femors of a rat were cut away from the epiphysis,
Figure 6. Scanning electric microscopic view of ceramics ( β -TCP).