Purpose:
Adipose derived stem cell (ADSC) which is free from ethical controversy and rich in amount has great potential for bone tissue engineering applications. We have previously shown that additional platelet rich plasma (PRP) from a concentration of 5% to 7.5% increased ADSC osteogenic differentiation. Other studies also reported that extracellular calcium could induce ADSC proliferation, osteogenic gene expression and mineralization. Synergistic effect of PRP and extracellular calcium has not yet been explored. This study was aimed to determine the effect of extracellular calcium on PRP based osteogenic culturing medium (ODM) on ADSCs and to find the optimal culturing regimen for osteogenic differentiation of ADSC.
Materials and Methods:
The experiment was divided into 5 groups. For Group1 to Group4, ADSCs were cultured in 5% PRP based ODM with additional ionic calcium from 1.8mmol, 10mmol, 20mmol to 40 mmol respectively. Group 5 was control group in which cells were cultured in 5% PRP medium without extra calcium supplement. Osteogenic gene expressions including alkaline phosphatase (ALP), runt-related transcription factor 2 (Runx2), Osteocalcin (OCN), LRP5, α1C were quantified and compared by quantitative real-time PCR (qPCR) among groups. Alizarin Red S staining was done to assay bone deposition among groups.
Result:
In the presence of additional calcium in culturing medium, cell proliferation rate was significantly higher. The qPCR showed that ALP, Runx2, OCN, LRP5, α1C expression were all significantly increased in 20 mmol and 40 mmol calcium groups compared with control group (all p<0.05 respectively). The peak of ADSC mineralization was present for 20 mmol calcium treated group (p<0.05).
Conclusion:
In conclusion, we found that additional 20 mmol calcium with 5% PRP had better ability to promote osteogenic potential of ADSCs than using PRP alone. The result displays great potential to further bone repair and tissue engineering by ADSCs in the future.

Download