Platelet-Rich Fibrin is a Bioscaffold and Reservoir of Growth Factors for Tissue Regeneration

TLDR

Platelet‑rich fibrin is a rich source of autologous cytokines and growth factors widely used for tissue regeneration, yet its microstructure and distinguishing molecules from platelet‑rich plasma remain poorly characterized. The authors fabricated PRF using Choukroun’s protocol and generated a PRF extract by freezing at –80 °C. The extract promoted proliferation, migration, and differentiation of human alveolar bone marrow stem cells at 0.5 % concentration, revealed MMP9 and Serpin E1 as key factors absent in platelet‑rich plasma, and demonstrated that MMP9 directly regulates mineralization and that fresh PRF enhances critical‑size calvarial defect regeneration in mice, confirming PRF as a bioscaffold and growth‑factor reservoir.

Abstract

The platelet-rich fibrin (PRF) is known as a rich source of autologous cytokines and growth factors and universally used for tissue regeneration in current clinical medicine. However, the microstructure of PRF has not been fully investigated nor have been studied the key molecules that differ PRF from platelet-rich plasma. We fabricated PRF under Choukroun's protocol and produced its extract (PRFe) by freezing at -80°C. The conventional histological, immunohistological staining, and scanning electron microscopy images showed the microstructure of PRF, appearing as two zones, the zone of platelets and the zone of fibrin, which resembled a mesh containing blood cells. The PRFe increased proliferation, migration, and promoted differentiation of the human alveolar bone marrow stem cells (hABMSCs) at 0.5% concentration in vitro. From the results of proteome array, matrix metalloproteinase 9 (MMP9) and Serpin E1 were detected especially in PRFe but not in concentrated platelet-rich plasma. Simultaneous elevation of MMP9, CD44, and transforming growth factor β-1 receptor was shown at 0.5% PRFe treatment to the hABMSC in immunoblot. Mineralization assay showed that MMP9 directly regulated mineralization differentiation of hABMSC. Transplantation of the fresh PRF into the mouse calvarias enhanced regeneration of the critical-sized defect. Our results strongly support the new characteristics of PRF as a bioscaffold and reservoir of growth factors for tissue regeneration.