Biological characterization and in vitro effects of human concentrated growth factor preparation : An innovative approach to tissue regeneration

Scientific background: Platelet concentrates are nowadays widely applied in different clinical fields to improve soft tissue and bone regeneration. "Concentrated Growth Factors" (CGF) is a new generation of platelet concentrate products, which exhibits an interesting clinical and biotechnological application potential. Aim of the study: The aim of this study is to assess the biological rationale for the use of CGF, by evaluating blood cell localization, the in vitro cumulative release of seven growth factors (PDGF-AB, VEGF, TNF-a, TGF-ß1, BDNF, BMP- 2 and IGF-1), its in vitro effects on cell proliferation and its mechanical behavior. Methods: CGFs were obtained from volunteer donors. Blood cell localization was evaluated after properly morphological staining and immunohistochemistry. The amount of growth factors release was measured at 5 hours, 1, 3, 6, 7 and 8 days, using ELISA assay. Cells were cultured with and without CGF and their proliferation were evaluated after 72 hours, performing the quantification of Ki-67, using flow cytometry (FACS). The mechanical response of CGF under compression was also attempted. Results: The results showed that platelets and leukocytes were found in a very thin space called "buffy coat", localized between the white and red part of CGF. Each growth factor evaluated, had a specific kinetic release with a great variability among subjects. The in vitro cell proliferation was stimulated. CGF showed an "apparent plasticity" and its mechanical response was influenced by fibrin network structure. Conclusion: These findings support the CGF's clinical use and will allow us to better understand and improve the clinical outcomes.