Homologous activated platelets stimulate differentiation and proliferation of primary human bone cells.

In bone tissue engineering approaches the expansion of bone cells is an essential part. In recent years the search for an appropriate alternative to fetal bovine serum (FBS) in the ex vivo expansion process has increased. This study demonstrates that platelet-rich clot releasate (PRCR) could be an appropriate alternative. The effects of PRCR on bone cell cultures derived from 5 different human donors were analyzed with respect to morphology, proliferation, apoptosis and gene expression. Five different PRCR concentrations were used: 1, 5, 10, 20 and 40%. The population doubling (PD) values were calculated for each concentration. Light microscopy analysis was done after 3 and 9 days. Flow cytometry was used to analyze cell cycle effects. The gene expression of alkaline phosphatase, collagen type 1, osteocalcin, bone sialoprotein and osteopontin was analyzed with RT-PCR. 10% FBS cultures were used as controls. With 10% PRCR the cell morphology resembled the control cultures; however, the PD values were significantly higher (p < 0.01). Concentrations of 20 and 40% had a clear cytotoxic effect, observed with light microscopy analysis and flow cytometry. PRCR had a potent effect on the expression of osteogenic markers and resulted in a concentration-dependent upregulation. We demonstrate that human bone cells derived from the maxillary alveolar ridge can be cultured in medium containing PRCR instead of FBS. The addition of PRCR results in higher proliferative capacity and upregulation of osteogenic markers. These results indicate that FBS could be avoided in future tissue engineering approaches using bone cells from this anatomic site.