Human umbilical cord blood (UCB) is a source of hematopoietic stem cells and progenitor cells. The frequency of hematopoietic stem cells and progenitor cells in UCB is greater than the frequency in bone marrow and peripheral blood. Recently, it was shown that UCB contains various types of stem cells such as mesenchymal stem cells (MSCs), multipotent adult progenitor cells, unrestricted somatic stem cells, and endothelial progenitor cells.

The lymphocytes in UCB are functionally immature and UCB-derived progenitor cells can be maintained in long-term culture for more than 16 weeks, suggesting the presence of very primitive hematopoietic cells. In addition, use of human UCB as a stem cell source has several advantages over other cell sources, for example, human UCB is abundant and can be obtained with non-invasive methods that raise none of the ethical issues related to other human adult stem cell sources.

Platelet-rich plasma (PRP) contains a high concentration of human platelet growth factors in a small volume of plasma. The growth factors are obtained by lysing platelet bodies through temperature-shock or activating platelets to release growth factors. PRP contains platelet-derived growth factor (PDGF), basic fibroblast growth factor, vascular endothelial growth factor, insulin-like growth factor-1, and transforming growth factor-β (TGF- β). These growth factors are involved in wound healing and the repair of mineralized tissue.

Emerging literature demonstrates the beneficial effects of PRP in chronic non-healing tendon injuries including lateral epicondylitis, plantar fasciitis, and cartilage degeneration. The increasing need for clinical use of PRP necessitates more controlled studies and further understanding of PRP. Substantial heterogeneity exists in the studies with regard to patient populations, study designs, PRP preparation techniques, outcome measures, and observation periods.

The effects of PRP on the proliferation and differentiation of MSCs derived from bone marrow have been well studied. However, in dental research, periodontal ligament cells are the most common source used in studies of the effects of PRP on proliferation and differentiation in vitro. In order to enhance wound healing in the dental clinic, PRP was used to provide growth factors in high concentrations to surgical wounds obtained from bone grafting, periodontal defects, sinus augmentation, oral-maxillofacial reconstructions, and bone formation in extraction sockets.

Recently, banking of cord blood as a hematopoietic stem cell source has become widely accepted and commercially feasible. During the process of banking cord blood, mononuclear cells are stored and red blood cells and plasma are usually discarded. Therefore, the plasma in cord blood can be another source of PRP.

The effects of PRP on dental stem cells derived from dental pulp have not been well studied. Moreover, the use of UCB-derived PRP (UCB-PRP) was elusive.

In this study, scientists investigated the effects of human UCB-PRP on the proliferation and osteogenic differentiation of human dental stem cells, which are stem cells from human exfoliated deciduous teeth (SHEDs), dental pulp stem cells (DPSCs), and periodontal ligament stem cells (PDLSCs). Various concentrations of UCB-PRP were examined and found to induce the proliferation and osteogenic differentiation of these dental stem cells. Scientific data show that treatment with 2% UCB-PRP induces high levels of proliferation and osteogenic differentiation in SHEDs, DPSCs, and PDLSCs. UCB-PRP contained similar levels of growth factors compared to peripheral blood-derived PRPs.

In conclusion, PRP is a valuable source of autologous serum and growth factors. Sufficient amounts of growth factors from UCB-PRP were obtained. Scientific data indicate that UCB-PRP may be used to promote the proliferation and osteogenic differentiation of SHEDs, DPSCs, and PDLSCs. The responses to UCB-PRP are different; therefore, the optimal concentration of UCB-PRP should be determined for each cell type. Similar to PRP derived from peripheral blood, UCB-PRP may contain unknown components that have beneficial effects on the proliferation and differentiation of MSCs. For the clinical application of UCB-PRP, more studies such as in vivo transplantation and banking methods are required.