Bone regeneration of localized chronic alveolar defects utilizing cell binding peptide associated with anorganic bovine-derived bone mineral: a clinical and histological study

Combination of bone substitutes and vectors in periodontology and implantology: A systematic review

The aim of the systematic review was to analyze the use of combination of bone substitutes and vectors in periodontology and implantology among animals models and humans. Electronic databases were searched, and additional hand search was performed. The research strategy was achieved according to the PRISMA guidelines. The including criteria were: combination of bone substitutes and vectors, in vivo studies, a precise number of specimens, histological and radiographic analysis, written in English. The risk of bias was evaluated for individual studies. Thirty-two articles were selected and investigated in this systematic review. The results do not show a superiority of the use of composite biomaterial in comparison with simple biomaterial but suggest the efficacity of their utilization as a carrier of bioactive agents. Future studies need to identify the suitable association of bone substitutes and vectors and explore interest in their use such as the support of growth factors.

Clinical effectiveness of anorganic bovine-derived hydroxyapatite matrix/cell-binding peptide grafts for regeneration of periodontal defects: a systematic review and meta-analysis

Aim: To ascertain clinical effectiveness of anorganic bovine-derived hydroxyapatite matrix/cell-binding peptide (ABM/P-15) for regeneration of periodontal defects. Materials & methods: Electronic databases (National Library of Medicine [Medline by PubMed], Cochrane Library [Wiley], CINAHL [EBSCO] and Medline [EBSCO]) were systematically searched up to December 2019. Randomized controlled clinical trials comparing ABM/P-15 grafts to conventional surgery for intrabony and gingival recession defects were included and evaluated intrabony defects including clinical attachment level (CAL), probing depth and gingival recession. Results: A significant gain in CAL (1.37 mm), and reduction in probing depth (1.22 mm) were shown by ABM/P-15 grafts than open flap debridement (p < 0.00001). The subgroup analysis also showed better results for ABM/P-15 grafts in CAL gain for intrabony defects. For furcation and gingival recession defects, no significant difference was seen. Conclusion: The adjunct use of ABM/P-15 grafts in conventional periodontal surgery is useful for periodontal regeneration of intrabony defects.

Comparing bone tissue engineering efficacy of HDPSCs, HBMSCs on 3D biomimetic ABM-P-15 scaffolds in vitro and in vivo

Human bone marrow mesenchymal stem cells (HBMSCs) has been the gold standard for bone regeneration. However, the low proliferation rate and long doubling time limited its clinical applications. This study aims to compare the bone tissue engineering efficacy of human dental pulp stem cells (HDPSCs) with HBMSCs in 2D, and 3D anorganic bone mineral (ABM) coated with a biomimetic collagen peptide (ABM-P-15) for improving bone-forming speed and efficacy in vitro and in vivo. The multipotential of both HDPSCs and HBMSCs have been compared in vitro. The bone formation of HDPSCs on ABM-P-15 was tested using in vivo model. The osteogenic potential of the cells was confirmed by alkaline phosphatase (ALP) and immunohistological staining for osteogenic markers. Enhanced ALP, collagen, lipid droplet, or glycosaminoglycans production were visible in HDPSCs and HBMSCs after osteogenic, adipogenic and chondrogenic induction. HDPSC showed stronger ALP staining compared to HBMSCs. Confocal images showed more viable HDPSCs on both ABM-P-15 and ABM scaffolds compared to HBMSCs on similar scaffolds. ABM-P-15 enhanced cell attachment/spreading/bridging formation on ABM-P-15 scaffolds and significantly increased quantitative ALP specific activities of the HDPSCs and HBMSCs. After 8 weeks in vivo implantation in diffusion chamber model, the HDPSCs on ABM-P-15 scaffolds showed extensive high organised collagenous matrix formation that was positive for COL-I and OCN compared to ABM alone. In conclusion, the HDPSCs have a higher proliferation rate and better osteogenic capacity, which indicated the potential of combining HDPSCs with ABM-P-15 scaffolds for improving bone regeneration speed and efficacy.

The role of peptides in bone healing and regeneration: a systematic review

BACKGROUND

Bone tissue engineering and the research surrounding peptides has expanded significantly over the last few decades. Several peptides have been shown to support and stimulate the bone healing response and have been proposed as therapeutic vehicles for clinical use. The aim of this comprehensive review is to present the clinical and experimental studies analysing the potential role of peptides for bone healing and bone regeneration.

METHODS

A systematic review according to PRISMA guidelines was conducted. Articles presenting peptides capable of exerting an upregulatory effect on osteoprogenitor cells and bone healing were included in the study.

RESULTS

Based on the available literature, a significant amount of experimental in vitro and in vivo evidence exists. Several peptides were found to upregulate the bone healing response in experimental models and could act as potential candidates for future clinical applications. However, from the available peptides that reached the level of clinical trials, the presented results are limited.

CONCLUSION

Further research is desirable to shed more light into the processes governing the osteoprogenitor cellular responses. With further advances in the field of biomimetic materials and scaffolds, new treatment modalities for bone repair will emerge.

Evaluation of anorganic bovine-derived hydroxyapatite matrix/cell binding peptide as a bone graft material in the treatment of human periodontal infrabony defects: A clinico-radiographic study

Background:

Various bone graft materials have been used in the treatment of periodontal defects. A synthetic bone substitute material composed of P-15 with anorganic bone mineral has been scantly studied. Hence, the present study was aimed to evaluate and compare the efficacy of anorganic bovine-derived hydroxyapatite matrix (ABM)/cell binding peptide (P-15) in human periodontal infrabony defects with that of open flap debridement (OFD) alone.

Materials and Methods:

A split-mouth, randomized controlled clinical study was designed to investigate the efficacy of ABM/P-15. In this clinical trial, 10 patients having bilateral periodontal infrabony defects were treated either with ABM/P-15 or OFD and followed for a period of 9 months. At baseline and at 9 months probing pocket depth (PPD), relative attachment level (RAL), depth of a defect, and radiographic bone level were measured; and compared between test and control sites.

Results:

A statistically significant reduction (P < 0.001) in PPD was observed in test sites compared to control sites. Both sites showed a gain in RAL without any significant difference. Similarly, the radiographic evaluation revealed significantly higher radiographic defect fill in test sites as compared to control sites (P < 0.001).

Conclusion:

ABM/P-15 bone graft material appears to be useful and beneficial in the treatment of human periodontal infrabony defects.

Comparative study on the cellular activities of osteoblast-like cells and new bone formation of anorganic bone mineral coated with tetra-cell adhesion molecules and synthetic cell binding peptide

Purpose

We have previously reported that tetra-cell adhesion molecule (T-CAM) markedly enhanced the differentiation of osteoblast-like cells grown on anorganic bone mineral (ABM). T-CAM comprises recombinant peptides containing the Arg-Gly-Asp (RGD) sequence in the tenth type III domain, Pro-His-Ser-Arg-Asn (PHSRN) sequence in the ninth type III domain of fibronectin (FN), and the Glu-Pro-Asp-Ilu-Met (EPDIM) and Tyr-His (YH) sequence in the fourth fas-1 domain of βig-h3. Therefore, the purpose of this study was to evaluate the cellular activity of osteoblast-like cells and the new bone formation on ABM coated with T-CAM, while comparing the results with those of synthetic cell binding peptide (PepGen P-15).

Methods

To analyze the cell viability, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay was performed, andto analyze gene expression, northernblot was performed. Mineral nodule formations were evaluated using alizarin red stain. The new bone formations of each group were evaluated using histologic observation and histomorphometrc analysis.

Results

Expression of alkaline phosphatase mRNA was similar in all groups on days 10 and 20. The highest expression of osteopontin mRNA was observed in the group cultured with ABM/P-15, followed by those with ABM/T-CAM and ABM on days 20 and 30. Little difference was seen in the level of expression of collagen type I mRNA on the ABM, ABM/T-CAM, and ABM/P-15 cultured on day 20. There were similar growth and proliferation patterns for the ABM/T-CAM and ABM/P-15. The halo of red stain consistent with Ca²⁺ deposition was wider and denser around ABM/T-CAM and ABM/P-15 particles than around the ABM particles. The ABM/T-CAM group seemed to have bone forming bioactivity similar to that of ABM/P-15. A complete bony bridge was seen in two thirds of the defects in the ABM/T-CAM and ABM/P-15 groups.

Conclusions

ABM/T-CAM, which seemed to have bone forming bioactivity similar to ABM/P-15, was considered to serve as effective tissue-engineered bone graft material.

Small peptide (P-15) bone substitute efficacy in a rabbit cancellous bone model

P-15 is a synthetic 15-amino acid residue identical to the cell binding domain of type I collagen. P-15 can be adsorbed onto anorganic bovine bone mineral (ABM) and will enhance cell attachment and subsequent cell activation. Although ABM/P-15 has been studied as a bone graft substitute in the oral cavity, its use in orthopedic models has been limited. Thus, this study investigated the efficacy of ABM/P-15 treatment in a rabbit model of long bone cancellous healing. Defects were created in the distal femurs and proximal medial tibiae of rabbits and were filled with either ABMP/P-15 suspended in hydrogel, ABM alone suspended in hydrogel, hydrogel carrier alone, or no graft material. Rabbits were sacrificed at 1, 2, 4, or 8 weeks postsurgery, and the femurs and tibiae were harvested. Histomorphometric analyses indicated that defects treated with ABM/P-15 had significantly larger areas of new bone formation than the other three treatments at 2 and 8 weeks postsurgery. ABM/P-15 treated defects also had significantly more bone growth than defects left empty or filled with ABM alone at 4 weeks postsurgery. Furthermore, histological examination did not reveal acute inflammatory infiltrate cells in any of the treatment conditions. These results are consistent with the findings of ABM/P-15 use in human oral-maxillofacial studies and in large animal spine fusion models.

Ridge preservation with acellular dermal matrix and anorganic bone matrix cell-binding peptide P-15 after tooth extraction in humans

BACKGROUND

Preventing ridge collapse with the extraction of maxillary anterior teeth is vital to an esthetic restorative result. Several regenerative techniques are available and are used for socket preservation. The aim of this study is to analyze by clinical parameters the use of acellular dermal matrix (ADM) and anorganic bovine bone matrix (ABM) with synthetic cell-binding peptide P-15 to preserve alveolar bone after tooth extraction.

METHODS

Eighteen patients in need of extraction of maxillary anterior teeth were selected and randomly assigned to the test group (ADM plus ABM/P-15) or the control group (ADM only). Clinical measurements were recorded initially and at 6 months after ridge-preservation procedures.

RESULTS

In the clinical measurements (external vertical palatal measurement [EVPM], external vertical buccal measurement [EVBM], and alveolar horizontal measurement [AHM]) the statistical analysis showed no difference between test and control groups initially and at 6 months. The intragroup analysis, after 6 months, showed a statistically significant reduction in the measurements for both groups. In the comparison between the two groups, the differences in the test group were as follows: EVPM = 0.83 ± 1.53 mm; EVBM = 1.20 ± 2.02 mm; and AHM = 2.53 ± 1.81 mm. The differences in the control group were as follows: EVPM = 0.87 ± 1.13 mm; EVBM = 1.50 ± 1.15 mm; and AHM = 3.40 ± 1.39 mm. The differences in EVPM and EVBM were not statistically significant; however, in horizontal measurement (AHM), there was a statistically significant difference (P<0.05).

CONCLUSION

The results of this study show that ADM used as membrane associated with ABM/P-15 can be used to reduce buccal-palatal dimensions compared to ADM alone for preservation of the alveolar ridge after extraction of anterior maxillary teeth.

The bone formation capabilities of the anorganic bone matrix-synthetic cell-binding peptide 15 grafts in an animal periodontal model: a histologic and histomorphometric study in dogs

BACKGROUND

The aim of this study is to verify the regenerative potential of particulate anorganic bone matrix-synthetic peptide-15 (ABM-P-15) in class III furcation defects associated or not with expanded polytetrafluoroethylene membranes.

METHODS

Class III furcation defects were produced in the mandibular premolars (P2, P3, and P4) of six dogs and filled with impression material. The membranes and the bone grafts were inserted into P3 and P4, which were randomized to form the test and control groups, respectively; P2 was the negative control group. The animals were sacrificed 3 months post-treatment.

RESULTS

Histologically, the complete closure of class III furcation defects was not observed in any of the groups. Partial periodontal regeneration with similar morphologic characteristics among the groups was observed, however, through the formation of new cementum, periodontal ligament, and bone above the notch. Histologic analysis showed granules from the bone graft surrounded by immature bone matrix and encircled by newly formed tissue in the test group. The new bone formation area found in the negative control group was 2.28 + or - 2.49 mm(2) and in the test group it was 6.52 + or - 5.69 mm(2), which showed statistically significant differences for these groups considering this parameter (Friedman test P <0.05). There was no statistically significant difference among the negative control, control, and test groups for the other parameters.

CONCLUSIONS

The regenerative potential of ABM-P-15 was demonstrated through new bone formation circumscribing and above the graft particles. The new bone also was accompanied by the formation of new cementum and periodontal ligament fibers.

The design and use of animal models for translational research in bone tissue engineering and regenerative medicine

This review provides an overview of animal models for the evaluation, comparison, and systematic optimization of tissue engineering and regenerative medicine strategies related to bone tissue. This review includes an overview of major factors that influence the rational design and selection of an animal model. A comparison is provided of the 10 mammalian species that are most commonly used in bone research, and existing guidelines and standards are discussed. This review also identifies gaps in the availability of animal models: (1) the need for assessment of the predictive value of preclinical models for relative clinical efficacy, (2) the need for models that more effectively mimic the wound healing environment and mass transport conditions in the most challenging clinical settings (e.g., bone repair involving large bone and soft tissue defects and sites of prior surgery), and (3) the need for models that allow more effective measurement and detection of cell trafficking events and ultimate cell fate during the processes of bone modeling, remodeling, and regeneration. The ongoing need for both continued innovation and refinement in animal model systems, and the need and value of more effective standardization are reinforced.

Early effects of p-15 on human bone marrow stem cells

OBJECTIVES

Peptide-15 (P-15) is an analogue of the cell binding domain of collagen. P-15 has been shown to facilitate physiological to process in a way similar to collagen, to serve as anchorage for cells, and to promote the binding, migration and differentiation of cells. However, how P-15 alters osteoblast activity to promote bone formation is poorly understood. To study the osteoinductive properties of peptide P-15, we analyzed the expression levels of bone related genes in human mesenchymal stem cells treated with this biomaterial.

MATERIAL AND METHODS

Using real time Reverse Transcription-Polymerase Chain Reaction the quantitative expression of specific genes, like transcriptional factors (RUNX2 and SP7), bone related genes (SPP1, COL1A1, COL3A1, BGLAP, ALPL, and FOSL1) and mesenchymal stem cells marker (ENG) were examined.

RESULTS

P-15 causes a considerable induction of osteoblast transcriptional factor like osterix (SP7) and of the bone related genes osteopontin (SPP1) and osteocalcin (BGLAP). In contrast the expression of endoglin (ENG) was markedly decreased in stem cells treated with P-15 respect to untreated cells, indicating the differentiation effect of this biomaterial on stem cells.

CONCLUSIONS

The present study shows the effect of P-15 on mesenchymal stem cells in the early differentiation stages: P-15 is an inducer of osteogenesis on human stem cells as indicated by the activation of bone related markers SP7, SPP1 and BGLAP.The results may allow a better understanding of the molecular mechanism of bone regeneration and as a model for comparing other materials with similar clinical effects.

Bone regeneration after topical BMP-2-gene delivery in circumferential peri-implant bone defects

OBJECTIVES

The aims of this study were to evaluate the rate of bone formation and osseointegration after topical gene delivery with a liposomal vector system carrying bone morphogenetic protein (BMP)-2 cDNA in combination with a collagen carrier and autologous bone as a carrier in freshly created peri-implant bone defects.

MATERIALS AND METHODS

Eight domestic pigs received nine calvariae defects each (10 x 7 mm). A dental implant was inserted into the centre of each defect. In the test groups, the remaining space was filled with the liposomal vector/BMP-2 complex combined with a collagen carrier (n=18) or an autologous bone graft (n=18). Control groups were collagen only (n=18) and autologous bone graft only (n=18).

RESULTS

There was a significant difference in mineralisation rate in the BMP-2/bone graft (29.9%+/- 4.8 and 68.3%+/- 7.2) and bone graft only (22.6%+/- 2.6 and 49.4%+/- 13.9) groups after 7 and 28 days. Mineralisation values were also significantly higher in the BMP-2/collagen group (21.2%+/- 16.2 and 53.1%+/- 12.5) compared with the collagen-only group (8.2%+/- 7 and 41%+/- 8.1) in two different regions after 28 days. Also the bone-to-implant contact was significantly increased in the BMP-2/bone graft group after 28 days and in the BMP-2/collagen group after 7 and 28 days compared with their control groups.

CONCLUSIONS

The results of this study show a significantly positive effect of liposomal vector/BMP-2 on bone regeneration and osseointegration in bony circumferential peri-implant defects.

Differences in osteoblast miRNA induced by cell binding domain of collagen and silicate-based synthetic bone

PerioGlas (PG) is an silicate-based (i.e. anorganic) material used for grafting periodontal osseous defects since the ninety whereas P-15 is an analog of the cell binding domain of collagen (i.e. organic material) that is successfully used in clinical trial to promote bone formation. However, how PG (i.e anorganic material) and P-15 (i.e. collagen) differentially alter osteoblast activity to promote bone formation is unknown. We therefore attempted to get more insight by using microRNA microarray techniques to investigate the translation process in osteoblasts differentially exposed to PG and P-15. We identified 3 up-regulated miRNA (i.e. mir-30b, mir-26a, mir-92) and 8 down-regulated miRNA (i.e. mir-337, mir-377, mir-25, mir-200b, mir-129, mir-373, mir-133b, mir-489). The data reported are, to our knowledge, the first study on translation regulation in osteoblatsts differentially exposed to cell binding domain of collagen and to silicate-based material. Both enhance the translation of several miRNA belonging to osteogenetic genes, but P-15 acts preferentially on homeobox genes.

Experimental Intrabony and Periodontal Defects Treated With Natural Mineral Combined With a Synthetic Cell-Binding Peptide in the Canine: Morphometric Evaluations

BACKGROUND

A synthetic peptide (P-15) analog of collagen added to anorganic bovine bone mineral (ABM) has recently been used as an enhanced bone graft material (ABM/P-15). The objective of this study was to test the contribution of ABM/P-15 in a new putty form (PEP) in two experimental membrane-protected defects: periodontal and intrabony. Its efficacy as filler biomaterial in guided tissue regeneration (GTR) and guided bone regeneration (GBR) procedures was evaluated histologically and morphometrically.

METHODS

In the maxillary canines, a facial mucoperiosteal flap was raised bilaterally in nine dogs. Two circular defects, 5 mm in diameter and 2 mm in depth, were made on each side: a fenestrated periodontal on the canine root and an intrabony in the alveolar diastema, anteriorly. PEP particles filled both defects on one side; the contralateral side was blood filled (control). All surgical sites were covered with a bioabsorbable membrane. Histologically, at 4 months, tissue blocks were made using the cutting/grinding non-decalcification method followed by morphometric analysis. In the periodontal fenestration root surface, the linear percentage of new cementum (%CEM), area percentage of new bone (%NB), and residual biomaterial particles (%PEP) were calculated. These same measurements were calculated at the intrabony sites, except cementum. The amount of direct NB to PEP contact was measured to assess the osteoconductivity level (OSC). The Pearson correlation test was used to evaluate any significant relationship between the different measured parameters.

RESULTS

In the grafted and non-grafted fenestration root surface defects, %CEM averaged 59.5% and 73.9% (P <0.02), respectively; %NB averaged 36.1% and 31.4%, respectively; and %PEP averaged 20.6%. The mean percentage of OSC was 52.4%. In the intrabony grafted and non-grafted sites, %NB averaged 50.7% and 60.1%, respectively (P <0.02). Residual %PEP averaged 26.1%, and OSC averaged 35.6%. At the intrabony sites, higher %NB and lower %OSC were found compared to the fenestration sites (P <0.001 and P <0.03, respectively). Correlation analysis showed a negative correlation between %NB and %PEP at the fenestration defects. In between the two defect types, %OSC was significantly correlated (P <0.05).

CONCLUSIONS

ABM/P-15 putty showed osteoconductive and biocompatible qualities. However, at 4 months in this model, no enhanced regeneration was present compared to a higher CEM and NB growth detected at non-grafted membrane-protected sites.

Treatment of Class III Furcation Defects With Expanded Polytetrafluoroethylene Membrane Associated or Not With Anorganic Bone Matrix/Synthetic Cell-Binding Peptide: A Histologic and Histomorphometric Study in Dogs

BACKGROUND

Up until now, no predictable periodontal regeneration of Class III furcation defects has been demonstrated after treatment with different available techniques. Recently, a bone graft enriched with a peptide was developed and has shown satisfactory results when applied in intrabony defects. The aim of this study was to compare the use of expanded polytetrafluoroethylene (ePTFE) membrane associated (test group) or not (control group) with anorganic bovine-derived bone matrix (ABM)/synthetic peptide, in the treatment of Class III furcation defects in dogs.

METHODS

Six mongrel dogs were used in this study, and the second and fourth mandibular lower premolars were extracted. Class III furcation defects were surgically created in the third premolars and filled with impression material. Afterwards, the defects were surgically assessed for debridement and root planing. Teeth were randomly assigned into test and control groups. The membranes were removed after 4 weeks, and the animals were sacrificed 12 weeks later.

RESULTS

Comparisons between groups by the Wilcoxon signed rank test showed no statistically significant differences in the parameters evaluated. In the control group, a new bone area (NBA) of 41.71%+/-24.07%, connective tissue area (CTA) of 36.34%+/-15.50%, and epithelium tissue area (ETA) of 9.39%+/-5.85% were observed. The new cementum extension (NCE) was 24.16%+/-13.18%. The test group presented an NBA of 31.84%+/-12.58%, CTA of 47.72%+/-11.33%, ETA of 9.17%+/-6.81%, and an NCE of 30.13%+/-16.43%.

CONCLUSION

There was no statistically significant difference between the two therapies: ePTFE membrane associated with ABM/synthetic peptide flow or ePTFE membrane only.

Bioactivation of an anorganic bone matrix by P-15 peptide for the promotion of early bone formation

This animal experiment compared the regenerative processes within defined bony defects of the porcine skull after delivery of routinely utilized bone graft materials: anorganic bone matrix (ABM) and an identical ABM carrying the cell binding peptide P-15. Particulated autogenous bone was used as a control group. The chosen porcine model guaranteed the transferability of the obtained results to clinical practice. A total observation period of 6 months was defined. The bone samples were examined microradiographically and histologically at 8 specific times. Sufficient osseointegration and osseoconduction could be demonstrated for both anorganic bone minerals. However, in the selected model significantly higher mineralization rates (p = 0.0286) were found in the microradiographic image at 12 weeks after application of the bioactive form. The histological examination confirmed this accelerating effect on bone formation starting at day 3. At the end of the study after 6 months, the mineralization values had equalized in both study groups. For the first time, the material was demonstrated to be suitable as a bone substitute material for the treatment of larger bony defects in a large animal model. The P-15 sequence accelerated the process of bone formation on the surface of the anorganic bone matrix as early as 3 days but was not traced over the whole term of the study.

P-15 cell-binding domain derived from collagen: analysis of MG63 osteoblastic-cell response by means of a microarray technology

BACKGROUND

P-15 is an analog of the cell-binding domain of collagen. P-15 has been shown to facilitate physiological processes in a way similar to collagen; to serve as an anchorage for cells; and to promote the binding, migration, and differentiation of cells.

METHODS

Expression profiling by DNA microarray is a molecular technology that allows the analysis of gene expression in a cell system. By using DNA microarrays containing 19,200 genes, we identified in osteoblast-like cell line (MG-63) cultured with P-15 several genes whose expression was significantly up- or downregulated.

RESULTS

The differentially expressed genes cover a broad range of functional activities: 1) signaling transduction, 2) differentiation, 3) apoptosis, and 4) cell-cycle regulation. It was also possible to detect some genes whose function is unknown.

CONCLUSIONS

The data reported are, to our knowledge, the first genetic portrait of P-15 effects. They can help us to better understand the molecular mechanism of osteogenesis and can serve as a model for comparing different cell cultures and/or other materials with similar effect.