CONSIDERATIONS ON THE STRUCTURE OF BIOMATERIALS FOR SOFT- AND HARD-TISSUE ENGINEERING - Intelligent Scaffolds for Tissue Engineering and Regenerative Medicine - page 525

26.3.3 Fate of Transplanted Scaffolds in the Human Body:
A Clinical Study of Alveolar Bone Tissue Engineering
Using Bone Marrow Stromal Cells and β -TCP

Among the biomaterials used for bone tissue engineering, the fate
of ceramic-based materials has been relatively well described since
these materials can be used alone as bioartificial bone substitutes
such as β -TCP. 3 - 6 However, the degradation process of β -TCP in vivo
is much different from that in vitro . Transplants are immersed in
an aqueous solution with ions and enzymes at various pHs. Fur-
thermore, cells such as osteoclasts are known to interact with the
materials and play some role during the degradation process.
BiodegradationofTCPisconsideredtobemediatedintwodifferent
ways: (1) resorption by osteoclasts and (2) dissolution by intersti-
tial fluid. 4 Interestingly, when TCP was transplanted alone without
cells, Zerbo et al . reported that osteoclastic activity did not precede
osteogenicactivityandmostofthedegradationmayhavehappened
as a result of a local drop in pH because of the production of acidic
by-productsandpoorlydevelopedvascularlizationintheregenerat-
ing tissue. 4
Ceramic-based materials have been used not only as bioartificial
bone substitutes, but also as scaffolds for bone tissue engineering.
Since only a limited number of publications are available on clin-
ical bone tissue engineering, information about the fate of β -TCP
as a scaffold is rather limited. However, cell-to-material interactions
should play important roles during the degradation process of the
scaffolds sincethe materials are transplanted withcells.
Wehaveperformedaclinicalstudyofalveolarboneregeneration
using autologous BMSCs and -TCP granules as a scaffold. BMSCs

were harvested from the iliac crest under local anesthesia and cul-
tured with

β

-minimum essential medium (MEM) containing 10%
autoserum and antibiotic/antimicotic reagents (Fig. 26.8). Nonad-
herent cells were discarded. After osteogenic induction for seven
days,adherentcellsweredetachedfromtheflasksandsuspendedin
platelet-rich plasma (PRP), which was turned into a gel using autol-
ogous thrombin. The gel was then mixed with β -TCP granules as a
scaffold and transplanted to the sinus floor and alveolar ridge to
obtain enoughbonevolumeto support the dental implant.

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