PepGen P-15 is a combination natural anorganic bovine-derived hydroxyapatite matrix (ABM) coupled with a synthetic cell-binding peptide (P-15). This material has been reported to enhance bone formation in periodontal osseous defects. The aim of this study was to assess the effect of ABM/P-15 on the healing of cortical bone defects in rabbits. Five New Zealand rabbits were used. Two 8-mm bone defects were created in each tibia. Eight defects were filled with PepGen P-15, 8 defects with PepGen P-15 Flow, and 4 defects were used as a control group. A total of 20 defects were created. All rabbits were killed at 4 weeks. Block sections containing the defects were retrieved and the specimens processed for light microscopy examination. Newly formed bone was present in both test groups, whereas, in the controlgroup, only a scarce quantity of newly formed bone was present and the cortical defects had not been filled by the regenerated bone. Statistical evaluation showed that there were statistically significant differences between control sites and sites treated with P-15 and P-15 Flow (P = 0.0001), and also between sites treated with P-15 and P-15 Flow (P = 0.0001), respectively. No acute inflammatory infiltrate cells were visible in both of these groups. Both PepGen P-15 and PepGen P-15 Flow enhanced new bone formation in the cortical drilled defects, whereas control defects showed very little newly formed bone.
PepGen P-15 is a new combination of natural anorganic bovine-derived hydroxyapatite (HA) matrix (ABM) coupled with a synthetic cell-binding peptide (P-15) that has demonstrated the capacity to improve the clinical defect fill in periodontal infrabony defects. 1 Bovine bone-derived porous HA is in a particulate form with a particle size of 250 to 420 μm. 1 HA has a mean pore volume of 0.13 mL/g and a total porosity of 28%. 2 The peptide P-15 is synthesized by solid phase procedures and absorbed on HA in a saturable manner. 2 There is also the possibility that P-15 not only increases the formation of new bone, but also can produce true periodontal regeneration. 1 Recently, Yukna et al. 1 showed true periodontal regeneration on a calculus- and plaque-contaminated area of the root.
A cell-binding domain of type I collagen has been identified. It has been shown that a 15-residue synthetic analogue (P-15) binds cells with high affinity. 2 It has been proposed that by incorporating P-15, the cell-binding activity of type I collagen in a three-dimensional distribution would facilitate the attachment, migration, and differentiation of cells in biologically inert templates. 2 The matrix with the immobilized peptide can be expected to emulate the properties of collagen in promoting cell attachment, migration, and differentiation. 2 Actually, it has been found that P-15 promoted the attachment and proliferation of human dermal and periodontal ligament fibroblasts on natural and synthetic HA particles and polyglycolide fibers, and allowed cell migration in the lattice of agarose hydrogel. 2
Moreover, it has been suggested that the synthetic peptide P-15 can serve as a force-transducing ligand in place of collagen and can facilitate the coupling of cellular tractional forces to the bulky mineral particles. 2