Potential Cell-Based Therapies for Irreversibly Damaged Salivary Glands and Atrophic Alveolar Bone - New Trends in Tissue Engineering and Regenerative Medicine - page 87

osteogenic cells. For this purpose, various parameters including cell separation procedures,
culture media, type and origin of serum, cell seeding density, timing of passaging, the number
of passages, content and concentrations of reagents for induction and the period of induction
should be optimized. Similarly, scaffold material and shape should be optimized depending
on the purpose. To establish a standard operating protocol for the preparation of cells for
clinical bone tissue engineering, we have investigated optimal cell culture and induction
procedures using human BMSCs and granular type β-tricalcium phosphate (β-TCP) as a
scaffold. The results showed that the passage number, seeding density and the period of
induction significantly affected the osteogenic ability of BMSCs (Agata et al., 2010). In
particular, human BMSCs lose their in vivo bone forming ability very rapidly after passaging
and no bone formation was observed with cells after the fourth cell passage (Fig. 3) (Agata et
al., 2010). The results of those basic studies should be considered in the establishment of an
optimal cell culture/induction protocol.
Figure 3. Effect of passage numbers on BMSC's ability for ectopic bone formation. Upper panels show ectopic bone
formation on the back of nude mice with tissue-engineered bone using human BMSCs at passage 1 (a) and passage 5
(b). The success of ectopic bone formation quickly decrease after cell passage and no bone formation was observed
after passage 4 (c). Note that the bone forming ability was quickly lost during passage. Adapted from Kagami et al.,
2014 and modified from original figure in Agata et al., 2010.