Homogeneous pressure influences the growth factor release profiles in solid platelet-rich fibrin matrices and enhances vascular endothelial growth factor release in the solid platelet-rich fibrin plugs

Abstract

Aims: Platelet-rich fibrin (PRF) exists in both solid and fluid forms. The present study was the first to evaluate the influence of homogeneous pressure on the growth factor (GF) release in pressed PRF-matrices and plugs. Methods and Material: A solid PRF-matrix (208 g; 8 min) was pressed to obtain a plug, and a pressed PRF-matrix that are used in clinical application. The released exudates were evaluated compared to liquid PRF (60 g and 3 min). The VEGF, TGF-s1 and EGF release was quantified using ELISA. The fibrin structure and cellular components in solid PRF groups were evaluated histologically. Results: The pressed PRF-matrix and PRF-plug exhibited denser fibrin structure compared to the non-pressed PRF-matrix. On day 7, the PRF-plug and non-pressed PRF-matrix showed significantly higher release of VEGF, TGF-s1 and EGF compared to that of the pressed PRF-matrix. The accumulated VEGF concentration was significantly higher in the PRF-plug compared to that in the PRF-matrix and non-pressed PRF-matrix. The accumulated EGF and TGF-s1 concentrations over 10 days showed no statistically significant differences between the evaluated solid PRF groups. The exudates released TGF-s1 and EGF passively, that was only detectable in after 1 and 7 hours. Liquid PRF released significantly higher GFs than the exudates at all investigated time points. The early VEGF and EGF release in liquid PRF (1 hour to 1 day) was significantly higher than that in the solid PRF-matrices. On day 10, significantly higher accumulated GFs were detected in the solid PRF groups compared to those in the liquid PRF. Thus, the combination of both solid and liquid PRF is a potential tool to generate a clinically relevant system with sustained bioactivity. Conclusions: These results highlight the potential to influence the GFs release profile of solid PRF matrices by pressure and obtain a clinically applicable plug with significantly higher VEGF release, providing further understanding of the release profile of PRF matrices as a drug delivery system.