Table 4.
In vitro studies on PRF and tenogenesis.
| Hemocomponent/Experimental Groups | PRF Preparation Protocol | Characterization Parameters | Major Findings | Reference |
|---|---|---|---|---|
| - Human PR-matrix - Human PP-matrix - Human purified fibrin |
- Blood collection into 3.8% (wt/vol) sodium citrate - Centrifugation at 4 °C: (a) PR-plasma → 460× g, 8 min (b) PP-plasma → 4500× g, 12 min - Platelet counts before clotting - Addition of calcium chloride at a final concentration of 22.8 mM |
- Proliferation of human tenocytes - Secretion of TGF-β1, VEGF and HGF (+/− cells) - Synthesis of type-I collagen (Coll-I) |
- Significantly increased platelets cells proliferation - Increase in Coll-I synthesis with any difference between PR- and PP-matrices - Higher levels of TGF-β1 in PR-matrix samples (i.e., +/− tenocytes) than PP-matrices - Increased synthesis of VEGF and HGF by tenocytes on fibrin matrices - Significantly higher levels of VEGF, but not HGF, in presence of platelets |
Anitua et al., 2006 [101] |
| - Dog PRF matrix - Dog PRF membrane - Dog whole blood clot |
a) PRF matrix - Blood collection in tube with trisodium citrate - 1st centrifugation (1100× g, 6 min) - Supernatant transfer in a tube with calcium chloride - 2nd centrifugation (1450× g, 15 min) b) PRF membran e- Blood collection in tube with trisodium citrate and the proprietary separator gel. - 1st centrifugation (1100× g, 6 min) - Supernatant transfer in a glass vial with calcium chloride - 2nd centrifugation (4500× g, 25 min) - Suspension of the resulting membrane in serum |
- Quantification of eluted TGF-β1 - Evaluation of the mitogenic effect on canine tenocytes |
- Both PRF constructs release significantly higher levels of TGF-β1 than blood clot, significantly increasing cell proliferation - Significantly higher levels of TGF-β1 were released from PRF membrane than PRF matrix, significantly increasing cell proliferation |
Visser et al., 2010 [102] |
| - Human standard/gelatinous L-PRF - Human dry/compressed L-PRF |
- Blood collection (at 8.30 am.) incitrate tubes - Centrifugation for 12 min with different G-forces: (1) 200× g, (2) 400× g, (3) 1000× g - Count of platelets, leukocytes and red blood cells in extracted supernatant and “buffy coat” versus normal blood |
- Leukocyte content - Release of GFs (i.e., TGF-β1, VEGF, MPO, IGF1, PDGF-AB, CXCL4) - Relationship between matrix preparation methods and GFs concentrations |
- Highest concentration of platelets and leukocytes with 400× g centrifugation - L-PRF clots showed in vitro a continuous release of GFs which were significantly higher than levels expressed by normal blood at each culture time point - Higher release of GFs (i.e., CXCL4, IGF-1, PDGF-AB, and VEGF) by the standard/gelatinous- compared to the dry/compressed group |
Zumstein et al., 2012 [111] |
| - Human PRF-matrix - Fibrin matrix based on PRP (ViscoGel; Arthrex, Naples, FL) Controls: - Human highly cross-linked collagen membrane (Arthroflex; LifeNet Health, Virginia Beach, VA) - Porcine non-cross-linked collagen membrane (Mucograft; Geistlich Pharma, Lucerne, Switzerland) - Human fresh-frozen rotator cuff tendon (allograft) |
- Blood collection - Centrifugation (3000 rpm, 10 min) |
- Differentiation, proliferation of human MSCs | - MSCs successfully differentiated into all cell lines - A significantly greater number of cells adhered to both the non-cross-linked porcine collagen scaffold and PRF-matrix - Significantly higher proliferation in the non-cross-linked porcine collagen scaffold vs PRF-matrix and fibrin matrix based on platelet-rich plasma - No significant differences at the live/dead assay |
Beitzel et al., 2014 [103] |
Coll-I, type-I collagen; CXCL4, Platelet Activity Factor; GFs, Growth Factors; HGF, Hepatocyte Growth Factor; IGF-1, Insulin Growth Factor-1; L-PRF, Leukocyte- and Platelet-Rich Fibrin; MPO, Myeloperoxidase; MSCs, Mesenchymal Stem Cells; PDGF-AB, Platelet-Derived Growth Factor-AB; PP, platelet-poor; PR, Platelet-rich; PRF, Platelet Rich Fibrin; TGF-β1, Transforming Growth Factor-beta1; VEGF, Vascular Endothelial Growth Factor; vs, versus. +/−, with or without.