Maxillofacial Bone Regeneration Using Tissue Engineering Concepts - Engineered Bone: Tissue Engineering Intelligence Unit - page 185

Tranforming Growth Factor- β
The transforming growth factor- β (TGF- β ) gene superfamily is one of the largest and most
diverse groups of related peptide growth factors that are important in tissue generation and
wound healing. TGF- β 1, the first member of this superfamily to be well studied originally
purified from human platelets and subsequently found in multiple normal tissues, including
cartilage and bone. 4-6 TGF- β may play a major role in bone generation, repair, and remodeling.
An interesting offshoot of this line of research is the tissue engineering implications: the ability
of various growth factors to induce bone formation in vivo for reconstruction of bone defects.
Transforming growth factor- β 1 induces woven bone formation in vivo when injected onto
the periosteum of rat and mouse cranium and onto the perichondrium of rabbit ears. In addi-
tion, when combined with a demineralized bone matrix (DBM) carrier, both TGF- β 1 and
TGF- β Z (recombinant hybrid of TGF- β 1 / TGF- β 2) accelerate osteoinduction in a craniofa-
cial onlay mode in rabbits.
Platelet-Rich Plasma
Platelet rich plasma (PRP) contains a high concerntration of growth factors, which are
universal initiators for almost all pathway of wound healing. 7 By using these identified growth
factors and nonidentified growth factors in platelets, we tried to perform the bone regenera-
tion.
Animal Experiment
Our study was designed to examine whether PRP with β -tricalcium phosphate ( β -TCP)
would improve ossification of the graft using rabbit. PRP is prepared from the peripheral blood
by the manner of Figure 3, and the remaining blood components are delivered back into the
rabbit. All animals received human care in compliance with the “Guidelines for the Care and
Use of Laboratory Animals”published by the National Institutes of Health (NIH Publication
no. 85-23, revised 1985). The maxillary sinus floors in 4 adult rabbits were augmented with β -
TCP combined with PRP on the test side and β -TCP on the control side (Fig. 4). They were
sacrificed, respectively, at 2 and 4 weeks after surgery to evaluate bone formation.
Histologic evaluation documented a significant amount of newly formed bone along the
β -TCP at 4 weeks on both sides, indicationg that β -TCP used in this study had good
osteoconductivity. The bone volume fraction at the augmented area on the test sites was higher
Figure 3. Preparation method of PRP by two-time revolutions.