The effect of Emdogain® and platelet-derived growth factor on the osteoinductive potential of hydroxyapatite tricalcium phosphate

Abstract

The aim of this study was to determine whether hydroxyapatite β-tricalcium phosphate (HA-TCP) either alone or coated with Emdogain (EMD) or recombinant human platelet-derived growth factor-BB (rhPDGF-BB) becomes osteoinductive in the murine thigh muscle model for osteoinduction. Twenty CD1 adult male mice had gelatin capsules implanted into the thigh muscle of both hind limbs. The capsules were either empty or contained one of the following: uncoated particulate HA-TCP, EMD-coated HA-TCP or rhPDGF-BB-coated HA-TCP. The implant sites were assessed histologically at 4 and 8 weeks. A semi-quantitative histological examination was performed to assess the inflammatory changes, reparative processes and osteoinduction within the graft site. At both 4 and 8 weeks, histological analysis failed to demonstrate any osteoinductive activity in any of the specimens from the experimental groups. A minimal chronic inflammatory response and foreign body reaction around the implanted materials was seen which reduced over time. The HA-TCP particles were embedded within fibrous connective tissue and were encapsulated by a dense cellular layer consisting of active fibroblasts and occasional macrophages with the thickness of this layer decreasing over time. The results of this study suggest that the use of commercially available HA-TCP alone or in combination with EMD or rhPDGF-BB is biocompatible but not osteoinductive in the murine thigh muscle model of osteoinduction. Coating HA-TCP with EMD or rhPDGF-BB does not enhance its osteoinductive potential.

Tissue reactions after simultaneous alveolar ridge augmentation with biphasic calcium phosphate and implant insertion—histological and immunohistochemical evaluation in humans

“…Osteogenic processes around granules observed in this study resembled membraneous osteogenesis with the stages osteoid formation, mineralization, generation of fibrous bone, and later remodeling into mature bone, which demonstrates the osteoconductive property of bone substitute materials as already described in previous studies [13,16,23]. Findings from animal experiments could not evidence any osteoinduction upon BCP application, as ectopic bone formation could not be observed [17,18]. However, our results are in concordance with studies analyzing undecalcified specimens that certify intimate contact between newly formed bone and BCP surfaces, which provides tissue stability and volume preservation as important factors for clinical success of augmentation and implant long-term stability [6,15,19].…”

“…In a study evaluating the healing of the same BCP as used in this study after sinus lift, Frenken et al [16] have also investigated decalcified biopsy specimens, however, using standard histological staining. Immunohistochemical analyses were successfully applied in some animal studies investigating the behavior of ectopic BCP combined with enamel matrix derivative or platelet-derived growth factor in mice [17,18].…”

Osteoinduction

“…Studies in immunocompromised mice have revealed that PDGF (Ranly et al, 2005) and platelet-rich plasma (Ranly et al, 2007) decrease the osteoinductivity of DBM. Furthermore, a recent study comparing the osteoinductive effects of a hydroxyapatite/TCP scaffold in combination with enamel matrix derivative or PDGF displayed no signs of osteoinduction in a murine thigh muscle model in mice (Chan et al, 2011).…”

Bone Regenerative Potential of Enamel Matrix Protein in the Circumferential Defect Around a Dental Implant

“…In an ectopic transplantation model, EMD consistently did not exhibit an osteoinductive effect. 22,24,39,40 When space was provided by defect preparation or the use of a membrane, the outcomes were heterogeneous. 17,20,25 EMD application in a membrane-protected space did not influence bone regeneration in rats, 25 whereas EMD in combination with BCP or bovine bone mineral induced significant new bone formation in cylindrical defects in dog mandibles and rat femurs.…”