Scientific Literature



Background and Objectives: L-PRF (Leukocyte- and Platelet-Rich Fibrin) is one of the 4 families of platelet concentrates for surgical use and is widely used in oral and maxillofacial regenerative therapies. The objective of this third article was to evaluate how the changes of the L-PRF protocol may influence its biological signature, independently from the characteristics of the centrifuge.


Materials and Methods: In each volunteer donor, veinous blood was taken in 2 groups, respectively Intra-Spin 9ml glass-coated plastic tubes (Intra-Lock, Boca-Raton, FL, USA) and A-PRF 10ml glass tubes (Process, Nice, France). Tubes were immediately centrifuged at 2700 rpm (around 400g) during 12 minutes to produce L-PRF clots, or at 1500 rpm during 14 minutes to produce A-PRF clots. All centrifugations were done using the original L-PRF centrifuge (Intra-Spin system, Intra-Lock), as recommended by the 2 manufacturers. All clots were collected into a sterile surgical box (Xpression kit) and compressed into membranes. Half of the membranes were placed individually in culture media and transferred in a new tube at 7 experimental times: 20 minutes, 1 hour, 4h, 24h, 72h, 120h and 168h. The releases of Transforming Growth Factor ß-1 (TGFß-1), Platelet Derived Growth Factor AB (PDGF-AB), Vascular Endothelial Growth Factor (VEGF) and Bone MorphogeneticProtein 2 (BMP-2) were quantified using ELISA kits at these 7 experimental times. The remaining membranes were used to evaluate the initial quantity of growth factors of the L-PRF and A-PRF membranes, through forcible extraction.


Results: The slow release of the 3 tested growth factors (TGFß-1, PDGF-AB and VEGF) from original L-PRF membranes was significantly much stronger (more than twice stronger, p < 0.001) at all experimental times than the release from A-PRF membranes. No trace of BMP2 could be detected in the A-PRF membrane. A slow release of BMP2 was detected during at least 7 days in the original L-PRF. Moreover, the original L-PRF clots and membranes (produced with 9mL blood) were always significantly larger than the A-PRF clots and membranes (produced with 10mL blood). The A-PRF membranes dissolved in vitro after less than 3 days, while the L-PRF membrane remained in good shape during at least 7 days.


Discussion and Conclusion: The cumulative curves are defining the biological signatures of the tested product. The original L-PRF signature is always more than twice stronger than the A-PRF signature. The same centrifuge was used for both products in this study; only the protocol (particularly the centrifugation forces) was different. The original L-PRF protocol allowed producing larger clots and membranes and a more intense release of growth factors than the modified A-PRF protocol. The exact impact of the tubes should also be investigated in the future. Both protocols are therefore very significantly different, and the clinical and experimental results from the original L-PRF shall not be extrapolated to the A-PRF. Finally, the comparison between the total released amounts and the initial content of the membrane (after forcible extraction) highlighted that the leukocytes living in the fibrin matrix are involved in the production of significant amounts of growth factors.


Keywords: Blood platelets, growth factors, leukocytes, platelet-rich plasma, regenerative medicine, wound healing.

The impact of the centrifuge characteristics and centrifugation protocols on the cells, growth factors and fibrin architecture of a Leukocyte- and Platelet-Rich Fibrin (L-PRF) clot and membrane. Part 3: comparison of the growth factors content and slow release between the original L-PRF and the modified A-PRF (Advanced Platelet-Rich Fibrin) membranes.



POSEIDO, Volume 2, Issue 2, June 2014, Pages 155-66


Medicine: 5

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