Effect of rhTGF-β1 combined with bone grafts on human periodontal cell differentiation

Various techniques and materials have been proposed for the treatment of periodontal defects. In periodontal regeneration, periodontal ligament (PDL) cell differentiation as well as certain growth factors and their delivery system applied are critical. The purpose of this study was to evaluate the in vitro effect of recombinant human transforming growth factor-beta 1 (rhTGF-β1) combined with two different bone grafts on human PDL (hPDL) cell differentiation. The hPDL cells were treated with TGF-β1 alone or in combination with a calcified freeze-dried bone allograft (FDBA) and a porous biphasic calcium phosphate (BC) bone graft. Cell differentiation effect was estimated by measuring alkaline phosphatase (ALPase) activity and osteocalcin secretion. Results demonstrated that rhTGF-β1 alone or in combination with FDBA and BC provoked a significant (p<0.05) increase in ALPase activity as compared with controls. The findings of this study confirmed the beneficial role of rhTGF-β1 combined with FDBA and BC as carriers in periodontal regeneration.

Effect of rhBMP-7 combined with two bone grafts on human periodontal ligament cell differentiation

The purpose of this study was to evaluate the in vitro effect of recombinant human bone morphogenetic protein-7 (rhBMP-7) combined with demineralised freeze-dried bone allograft (DFDBA) and an inorganic bovine material with a synthetic peptide (PepGen P-15) on human periodontal ligament (hPDL) cell differentiation, in a time-dependent manner. hPDL cells were cultured and treated with: (1) 500 ng/ml of rhBMP-7, (2) 10 mg of DFDBA or PepGen P-15 and (3) their combination. Cell differentiation was estimated after 48 and 72 h by measuring alkaline phosphatase (ALPase) activity and osteocalcin (OC) secretion. The presence of rhBMP-7, DFDBA, PepGen P-15, rhBMP-7 + DFDBA and rhBMP-7+ PepGen P-15 promoted a significant increase of ALPase activity after 48 and 72 h. The combination of rhBMP-7 with DFDBA or PepGen P-15 did not lead to significant OC secretion. The results of this study imply that rhBMP-7 stimulates the early osteoblastic differentiation of hPDL cells and that DFDBA and PepGen P-15 could serve as carriers for rhBMP-7.

Effect of homologous PRP on proliferation of human periodontally affected osteoblasts. In vitro preliminary study. Report of a case

OBJECTIVE

The purpose of this in vitro study was to evaluate the effect of two concentrations of homologous platelet-rich plasma (PRP) on the proliferative response of osteoblasts derived from a patient with aggressive periodontitis.

METHODS

8.5 ml of venous blood were taken from 1 healthy and non-smoker volunteer. PRP was prepared following the protocol of Curasan. Osteoblasts were derived from alveolar bone chips obtained from a patient with aggressive periodontitis during conventional periodontal surgery and a clinically healthy person during crown lengthening surgical procedure. Cells were grown in 24-well dishes and on day 2 of quiescence were treated with 1% and 5% (v/v) of PRP. The effect on cell proliferation was estimated by measuring [3H] thymidine incorporation. After 48h of incubation, cells were processed to subject to scintillation counting. Counts per minute were determined for each sample.

RESULTS

The addition of 1% and 5% of PRP provoked a statistical significant (p<0.05) increase in cell growth.

CONCLUSIONS

Data revealed significant enhancement of proliferative response of osteoblasts in the presence of PRP, which might serve as a source of growth factors promoting periodontal repair by modulating cell response and activities.

Role of growth factors on periodontal repair

Regeneration of periodontal structures lost during periodontal diseases constitutes a complex biological process regulated among others by interactions between cells and growth factors. Growth factors are biologically active polypeptides affecting the proliferation, chemotaxis and differentiation of cells from epithelium, bone and connective tissue. They express their action by binding to specific cell-surface receptors present on various target cells including osteoblasts, cementoblasts and periodontal ligament fibroblasts. The observation that growth factors participate in all cell functions led to exogenous application during periodontal tissue repair aiming to their use as an alternative therapeutic approach to periodontal therapy. Cell types and cultures conditions, dose, carrier materials, application requirements are of critical importance in the outcome of periodontal repair. The purpose of this article is to review the literature with respect to the biological actions of PDGF, TGF, FGF, IGF and EGF on periodontal cells and tissues, which are involved in periodontal regeneration.

Ability of a bovine bone graft, alone or enriched with PDGF-BB or rhBMP-2, to promote human periodontal ligament (PDL) cells proliferation. A preliminary study

One of the most important goals of the periodontal therapy procedures is to stimulate the formation of new bone into osseous defects resulted from periodontal disease. A wide range of grafting materials is used to achieve this aim. Recently, the Human Tissue Bank of the National Center for Scientific Research 'Demokritos' in Athens (Greece) has prepared, in a preliminary study, a cancellous bovine-derived bone matrix (BBM). The purpose of the present work was to investigate the role of this bovine bone material in the periodontal regeneration, by studying the rate of human periodontal ligament (PDL) cells proliferation in the presence of this matrix alone, or after the addition of the growth factors, platelet-derived growth factor-BB (PDGF-BB) or recombinant human bone morphogenetic protein-2 (rhBMP-2).Bovine bone graft was prepared using the 'know how' acquired by the 30 years continuous preparation and delivery of lyophilized human bone grafts by the 'Demokritos' Bank.PDL cells cultures were derived from the mid root of two maxillary premolars. The teeth were caries-free and were extracted for orthodontic reasons from 1 adult female patient. Cells were grown in 24-well dishes in the presence of 20 mg BBM. On day 2 of quiescence, new medium was added with 10 ng/ml of PDGF-BB or 50 ng/ml of rhBMP-2. To determine the effects of the test agents on cell proliferation, DNA synthesis was estimated by measuring [(3)H] thymidine incorporation. After 48 h of incubation the cells were processed to subject to scintillation counting. Counts per minute (cpm/well) were determined for each sample.The results revealed that this BBM has the ability to maintain PDL cells proliferation and could be used as an alternative graft material. PDGF-BB when added improved the cell proliferative response resulting in a more active BBM, while the presence of rhBMP-2 did not support cell mitosis.

Human periodontal ligament cell responses to recombinant human bone morphogenetic protein-2 with and without bone allografts

BACKGROUND

Recombinant human bone morphogenetic protein-2 (rhBMP-2) has been found to promote the osteoblastic differentiation of human periodontal ligament cells. Its effect depends on the delivery system used. In this study we examined the effect of rhBMP-2 on the proliferation and osteoblastic differentiation of human periodontal ligament cells cultured alone or with 3 different bone allografts.

METHODS

The rhBMP-2 effect on cell proliferation and osteoblastic differentiation was examined by measuring [3H] thymidine incorporation and ALPase activity, respectively, on human periodontal ligament (hPDL) cells. Two human demineralized freeze-dried allografts of cortical (DFDBAco) and cancellous (DFBDAca) bone origin and 1 non-demineralized freeze-dried allograft (FDBA) of cancellous bone origin, derived from different tissue banks, were used to evaluate the rhBMP-2 effect on cell osteoblastic differentiation. The measurements were taken on various days.

RESULTS

rhBMP-2 decreased hPDL cell proliferation. rhBMP-2 acted on the third day of the process of cell differentiation, had a specific time of action, achieved its peak effect on the fourth and fifth days, and then did not provoke any further effects. The 3 bone allografts were efficiently combined with rhBMP-2. The combination of rhBMP-2 and DFDBAco showed the effect with the longest duration. rhBMP-2, on day 4, made the inactive bone allograft more active while, on the other days, its effect was dependent on the allograft alone.

CONCLUSIONS

rhBMP-2 promotes the osteoblastic differentiation of human periodontal ligament cells and decreases cell proliferation. In this study rhBMP-2 in the presence of the bone allografts tested resulted in hPDL cell differentiation.