Platelet‐rich plasma and fibrin as delivery systems for recombinant human bone morphogenetic protein‐2

Abstract

The aim of the present study was (1) to test whether or not platelet-rich plasma (PRP) or commercially available fibrin can increase bone regeneration compared with non-treated defects and (2) to test whether or not PRP or fibrin increases bone regeneration when used as a delivery system for recombinant human bone morphogenetic protein-2 (rhBMP-2). In 16 New Zealand White rabbits, four evenly distributed 6 mm diameter defects were drilled into the calvarial bone. The following five treatment modalities were randomly allocated to all 64 defects: (0) untreated control, (1) fibrin alone, (2) PRP alone, (3) fibrin with 15 microg rhBMP-2 and (4) PRP with 15 microg rhBMP-2. For the fibrin gels and the PRP containing rhBMP-2, the 15 microg rhBMP-2 was incorporated by precipitation within the matrices before their gelation. After 4 weeks, the animals were sacrificed and the calvarial bones were removed for histological preparation. The area fraction of newly formed bone was determined in vertical sections from the middle of the defect by applying histomorphometrical analysis. A mean area fraction of newly formed bone was found within the former defect of 23.4% (+/-13.5%) in the control sites, of 28.4% (+/-17.4%) in the fibrin sites and of 34.5% (+/-17.4%) in the PRP sites. The statistical analysis revealed no significant difference in bone formation between the three groups (ANOVA). Addition of 15 microg rhBMP-2 in the fibrin gel (59.9+/-20.3%) and the PRP gels (63.1+/-25.3%) increased bone formation significantly. No significant difference was observed between sites, where PRP or fibrin has been used as a delivery system for rhBMP-2 (ANOVA). In conclusion, the application of fibrin gels or PRP gels to bone defects is not superior to leaving the defect untreated. Regarding the amount of bone formation, the application of 15 microg rhBMP-2 in bone defects enhances the healing significantly at 4 weeks. In this animal model, commercially available fibrin and autologous PRP gels are equally effective as delivery systems for rhBMP-2.

Growth Factor Interactions in Bone Regeneration

“…134 However, no statistically significant differences of platelet growth factor release was seen after combined implantation of rabbit PRP/BMP-2 gels compared to fibrin/BMP-2 gels in rabbit cranial defects. 135 Moreover, in a clinical trial, the combination of PRP and BMP has shown to be even less effective than BMPs alone. 136 In addition to the variation in experimental setups between these studies, growth factor concentrations in PRP are known to be variable between species and individuals, 137 all adding to the confusion around effectivity of PRP and combinations with BMPs.…”

Effect of BMP2–Platelet-rich Plasma–Biphasic Calcium Phosphate Scaffold on Accelerated Osteogenesis in Mastoid Obliteration

“…Another probable explanation may be the nature of the scaffold, which is autogenous or alloplastic. Additional use of PRP in autogenous bone scaffold stimulates osteogenesis by releasing several growth factors contained in PRP stimulating angiogenesis and the proliferation of osteoprogenitor cells only in the early period after transplantation; conversely, PRP has no positive effect on osteogenesis when used with alloplastic or xenogenic scaffolds (26). Moreover, PRP highly varies from donor to donor, and each PRP preparation can differ in its concentration of proteins and growth factors (27).…”

Regenerative Dentistry: Animal Model for Regenerative Endodontology

“…Fibrin gel appears to closely mimic a blood clot, without the inherent propensity of the latter to discolor the tooth. It is a material that can be modified easily to suit the application and has been approved by Food and Drug Administration [39]. Compared to other hydrogels it shows better results in cell proliferation and differentiation [40].…”