Freeze-Dried Platelet-Rich Plasma Induces Osteoblast Proliferation via Platelet-Derived Growth Factor Receptor-Mediated Signal Transduction

Abstract

This study aimed to evaluate the in vitro pharmacological activity of growth factors (GFs) in freeze-dried platelet-rich plasma (FD-PRP) after storage for 4 weeks. Overview of Literature: Freshly prepared PRP is a rich source of many GFs. We reported that FD-PRP stored for 8 weeks accelerated bone union in a rat posterolateral fusion model equally well as fresh-PRP. However, the pharmacological activity of FD-PRP after longterm storage has not been shown in vitro. Methods: Immediately after preparation, as well as 4 weeks after freeze-dried storage, the platelet count was measured. Human osteoblasts were treated with fresh-PRP and FD-PRP, respectively. Western blotting was used to assess the phosphorylation of the platelet-derived growth factor (PDGF) receptor (PDGFR) and its downstream target, extracellular signal-regulated kinase (ERK). The proliferation rates of osteoblasts were investigated by immunocytochemistry and MTT cell viability assays. Furthermore, we used western blotting to evaluate the effect of PDGFR knockdown on the phosphorylation of ERK stimulated with fresh-PRP and FD-PRP. Results: Platelet counts in both the fresh-PRP and FD-PRP samples were approximately 10-fold higher than in peripheral blood samples. The phosphorylation and activation of the PDGFR and ERK were evenly induced by fresh-PRP and FD-PRP stimulation. Both fresh-PRP and FD-PRP significantly induced osteoblast proliferation in MTT cell viability assays. Furthermore, osteoblast PDGFR knockdown attenuated the downstream ERK activation by fresh PRP and FD-PRP. Conclusions: We demonstrated the pharmacological activity of PDGF in FD-PRP in vitro after 4 weeks of storage.

Freeze-Drying of Platelet-Rich Plasma: The Quest for Standardization

“…In this study, all were combined with an artificial bone substitute, hydroxyapatite/collagen [54]. In addition, these authors confirmed the pharmacological activity of FD-PRP after a four-week storage by examining the PDGFR/ERK signal transduction in osteoblasts [55].…”

Clinical Safety Assessment of Autologous Freeze-Drying Platelet-Rich Plasma for Bone Regeneration in Maxillary Sinus Floor Augmentation: A Pilot Study

“…For instance, Shiga et al reported that FD-PRP maintained baseline levels of growth factor for an entire 8-week duration [ 6 ] and that FD-PRP accelerated bone formation with artificial bone used in a rat posterolateral fusion model [ 13 ]. Kinoshita et al reported that PDGF in FD-PRP is pharmacologically active in vitro after 4 weeks of storage [ 14 ]. It is also reported that FD-PRP significantly enhanced alkaline phosphatase activity and the mRNA expression level of osteogenic genes in vitro, and also that FD-PRP with scaffolds induced significantly greater bone formation compared to the traditional PRP in a rat calvaria defect [ 15 ].…”

“…PRP is thought to be effective in tissue regeneration because of its concentrated growth factors: the effectiveness of which can vary depending on the platelet concentration [ 14 ]. Marx suggested that a 4- to 9-fold concentration of platelets in the PB, or 100 × 10 4 platelets/mL, is needed in PRP for tissue healing enhancement [ 1 ].…”

Effects and mechanism of platelet-rich plasma on military drill injury: a review

“…In addition, some studies have shown that the mechanism whereby PRP promotes bone healing may be that platelets are involved in early response to bone injury and initiate the repair response by releasing growth factors, such as platelet derived growth factor (PDGF), insulin-like growth factor (IGF) and transforming growth factor-β (TGF-β) [ 64 , 65 ]. The healing process of stress fractures also involves the above growth factors, which provides a theoretical basis for the application of PRP in stress fractures.…”

“…Currently, it is not possible to apply PRP to war trauma, but the feasibility of PRP treatment of military drill injury in this review provides a possibility for the application of PRP in war trauma in the future. With the development of technology, PRP can be prepared in new formulations, such as PRP freeze-dried powder [ 64 ] and PRP wafer [ 78 ], or other formulations in the future, like PRP-loaded sterile dressing. Improvement of PRP formulation will render transport and long-term storage more convenient, and it is hopeful that PRP can be used as a trauma dressing in battlefield first aid.…”