The effect of platelet-rich plasma (PRP) combined with a bone allograft on human periodontal ligament (PDL) cells.

The prominent purpose of the study was the evaluation of the in vitro mitogenic effect of three different homologous platelet-rich plasma (PRP) preparations (PRPa, PRPb, PRPc) on three different lines of periodontal ligament (PDL) cells (PDL(1,2,3)), cultured alone or in combination with a demineralized freeze-dried allograft (DFBA). PDL cell cultures were derived from the mid root of three maxillary caries-free premolars extracted for orthodontic reasons. Cells were grown and reached confluence. To evaluate the mitogenic effect of all exogenous factors (PRPa, PRPb, PRPc and DFBA) on PDL cells, specific number of cells (10.000/well) was cultured in the presence or absence of the above factors. Each PRP preparation (5% v/v) was added in all cell lines, in the absence or presence of 10 mg/ml of DFBA. The cells were also treated with 25 ng/ml bFGF (positive control). The mitogenic effect was evaluated 24 h after incubation, using the Trypan blue exclusion assay. The results revealed that all PRP preparations act as potent mitogens as they significantly induced cell proliferation on PDL(1,2,3) lines. All PRP preparations when added alone in the PDL cell cultures, exhibited a significant advantage over the positive control (bFGF). The addition of DFBA to PRP did not influence significantly cell proliferation in all cell lines, comparatively to PRP alone, at the time -period studied. The findings of this study demonstrate the beneficial role of PRP alone or combined with the bone graft on periodontal ligament cells in vitro, suggesting that it may be considered as a potential biological approach in periodontal regeneration.

Effect of rhTGF-ß1 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-ß1) combined with two different bone grafts on human PDL (hPDL) cell differentiation. The hPDL cells were treated with TGF-ß1 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-ß1 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-ß1 combined with FDBA and BC as carriers in periodontal regeneration.

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.

Proliferative effect of growth factors TGF-beta1, PDGF-BB and rhBMP-2 on human gingival fibroblasts and periodontal ligament cells.

The regeneration of periodontal tissues lost due to periodontal disease requires cell migration, differentiation and proliferation. Several procedures have been proposed to promote wound healing events such as the application of growth factors including PDGF-BB, TGF-beta1 and rhBMP-2. The purpose of this study was to evaluate the mitogenic responses of human periodontal ligament cells and gingival fibroblasts to PDGF-BB, TGF-beta1 and rhBMP-2. Human periodontal ligament cells were isolated from the mid root of three maxillary third molars extracted from three adult patients with moderate periodontitis and gingival fibroblasts were obtained from two patients also affected by moderate periodontitis, who underwent periodontal surgery. Cells were grown in 24-well dishes. On day 2 of quiescence, new medium was added with PDGF-BB or TGF-beta1 or rhBMP-2 at the concentration of 10 ng/ml. To determine the effects of the test agents on cell proliferation, DNA synthesis was estimated by measuring [3H] thymidine incorporation. After 48h of incubation the cells were processed and subject to scintillation counting. Counts per minute (cpm/ well) were determined for each sample. The results of this study demonstrated that PDGF-BB acts like a strong mitogenic agent for human periodontal ligament cells and gingival fibroblasts, TGF-beta1 mostly supports the proliferation of these cells and rhBMP-2 had an opposite effect on cell mitosis.

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.

Correlation of lipophilicity to biodistribution of 99mTc-labelled aminothiols.

A series of 99mTc-DADT complexes substituted with heterocyclic amines were synthesized and tested for their ability to cross the BBB. Each 99mTc-DADT complex analysed by HPLC was found to consist of two epimers. The more lipophilic epimers were biodistributed in mice. The data demonstrated a significant brain uptake (3-12% dose/g whole brain) and a high lung accumulation (11-85% dose/g) at 2 min p.i. Between the partition coefficients of the technetium complexes, a linear correlation for lung accumulation was observed, while a parabolic curve for brain uptake was found.

Red blood cell labelling by intravenous injection of 99mTc-PAEP.

In vivo red blood cell (RBC) labelling after the intravenous administration of PAEP (N- phosphorylamino -ethyl -phosphate) and the subsequent injection of sodium pertechnetate 24 hrs later was studied. The results in rats were found to be similar to those obtained after i.v. administration of 99mTc -PYP, a radiopharmaceutical routinely used for in vivo RBC labelling.

Structure-activity relationships of some technetium-99m labeled [(thioethyl)amino] carboxylates.

The synthesis, NMR studies, radiochemical labeling with technetium-99m, and tissue-distribution characteristics of some [(thioethyl)amino] carboxylates are described. The 99mTc agents prepared were eliminated either by the urinary of the hepatobiliary system of mice. The excretion route of the 99mTc complexes was influenced by the structure and total charge of the ligands.