Effect of benzalkonium chloride addition to EDTA on attachment and proliferation of dental pulp stem cells on dentin and on transforming growth factor-β1 release

Odontology - To investigate the effect of benzalkonium chloride (BAC) addition to ethylenediaminetetraacetic acid (EDTA) on transforming growth factor-β1 (TGF-β1) release, as well as...     

Osteoblast proliferation and differentiation on a barrier membrane in combination with BMP2 and TGFβ1

Objectives

Bioresorbable collagen membranes are routinely utilized in guided bone regeneration to selectively direct the growth and repopulation of bone cells in areas of insufficient volume. However, the exact nature by which alveolar osteoblasts react to barrier membranes as well as the effects following the addition of growth factors to the membranes are still poorly understood. The objective of the present study was therefore to investigate the effect of a bioresorbable collagen membrane soak-loaded in growth factors bone morphogenetic protein 2 (BMP2) or transforming growth factor β1 (TGFβ1) on osteoblast adhesion, proliferation, and differentiation.

Material and methods

Prior to experimental seeding, membranes were soaked in either BMP2 or TGFβ1 at a concentration of 10 ng/ml for 5 min.

Results

Human osteoblasts adhered to all soak-loaded membranes as assessed by scanning electron microscopy. Growth factors BMP2 and TGFβ1 increased osteoblast proliferation at 3 or 5 days post-seeding when compared to control collagen membranes. Analysis of real-time PCR revealed that administration of BMP2 increased osteoblast differentiation markers such as osterix, collagen I, and osteocalcin. BMP2 also increased mineralization of primary osteoblasts as demonstrated by alizarin red staining when compared to control and TGFβ1 soak-loaded membranes.

Conclusion

The combination of a collagen barrier membrane with growth factors TGFβ1 and BMP2 significantly influenced adhesion, proliferation, and differentiation of primary human osteoblasts.

Clinical relevance

The described in vitro effects following the combination of collagen barrier membranes with growth factors TGFβ1 and BMP2 provide further biologic support for the clinical application of this treatment strategy in guided bone regeneration procedures.     

The role of integrin β1 in human dental pulp cell adhesion on laminin and fibronectin

Objective. This study is to identify the expression of integrin β₁ in human dental pulp cells and the role of integrin β₁ in pulp cell adhesion on extracellular matrix protein laminin and fibronectin.Study design. Immunoblot detection of integrin β₁ in human dental pulp cells was with the use of monoclonal anti-β₁ antibody. Dental pulp cell adhesion assay on extracellular matrix protein laminin and fibronectin and blocking cell adhesion was performed with monoclonal anti-β₁ antibody.Result. Integrin β₁ was identified in human dental pulp cells. Pulp cells adhered and spread on both laminin and fibronectin. Monoclonal anti-β₁ antibody inhibited human dental pulp cells adhesion on laminin but not on fibronectin.Conclusions. Integrin β₁ was expressed on human dental pulp cells and mediated cell adhesion on laminin. Human dental pulp cells also adhered on fibronectin but the adhesion was not regulated by β₁ integrin.     

Effect of titanium surface on secretion of IL1β and TGFβ1 by mononuclear cells

Mononuclear cells play an important role in the modulation of healing. The characteristics of implant surface topography may alter the production of signaling molecules such as cytokines. The aim of this in vitro study was to evaluate the effects of commercially available titanium surface treatments on both cell viability and the secretion of the antagonist cytokines, IL1β and TGFβ1. Human mononuclear cells were cultured on 10 mm diameter commercially pure titanium (cpTi) disks that were prepared using a turning procedure (control = machined surface) and either acid etched or bio-anodized for 1-7 days. Adhered cells were investigated with respect to cell viability using an MTT assay, and cytokine production was verified using an ELISA assay. The results indicate that surface characteristics did not alter the cell viability at days 1 and 4, although the machined surface presented the highest absorbance values at day 7 (p = 0.0084). Cell viability was reduced throughout the time course for all analyzed surfaces (p < 0.05). On day 4, IL1β levels were significantly higher on bio-anodized compared to acid etched surfaces (p = 0.0097). TGFβ1 did not show differences among the surfaces at days 1 and 4. The responses of non-stimulated mononuclear cells to titanium surfaces suggest only modest effects of the surface treatment and roughness on pro-inflammatory cytokine (IL1β) release.     

In vitro comparison of chlorhexidine and povidone–iodine on the long-term proliferation and functional activity of human alveolar bone cells

This work reports the behaviour of osteoblastic human alveolar bone cells (first subculture) in the presence of chorhexidine (CHX) and povidone–iodine (PI). Short contact (2 min) of 24-h cultures with CHX, at 0.12 and 0.2%, and PI, at 5 and 10%, caused cell death within minutes; contact with 1% PI resulted in loss of the elongated characteristic cell shape. Cell adhesion was adversely affected at concentrations higher than 5 × 10⁻⁵% CHX or 0.05% PI. Long-term exposure to CHX at 10⁻⁵ and 10⁻⁴% or PI at 10⁻⁴% had little effect on cell growth and caused an induction in the synthesis of alkaline phosphatase (ALP). Concentrations of CHX and PI similar and higher than, respectively, 5 × 10⁻⁴% or 0.05% caused dose-dependent deleterious effects. CHX affected mainly the cell growth, whereas the effects of PI were observed mostly in ALP production and matrix mineralization. Considering the levels of CHX and PI used routinely in the oral cavity, results suggest that CHX has a higher cytotoxicity profile than PI. This observation might have some clinical relevance regarding the potential utility of PI in the prevention of alveolar osteitis.     

Synergistic induction of periodontal tissue regeneration by binary application of human osteogenic protein-1 and human transforming growth factor-β3 in Class II furcation defects of Papio ursinus

Teare JA, Petit J‐C, Ripamonti U. Synergistic induction of periodontal tissue regeneration by binary application of human osteogenic protein‐1 and human transforming growth factor‐β ₃ in Class II furcation defects of Papio ursinus. J Periodont Res 2012; 47: 336–344. © 2011 John Wiley & Sons A/S Background and Objective: Binary applications of recombinant human osteogenic protein‐1 (hOP‐1) and transforming growth factor‐β3 (hTGF‐β3) synergize to induce pronounced bone formation. To induce periodontal tissue regeneration, binary applications of hOP‐1 and hTGF‐β₃ were implanted in Class II furcation defects of the Chacma baboon, Papio ursinus. Material and Methods: Defects were created bilaterally in the furcation of the first and second mandibular molars of three adult baboons. Single applications of 25 μg hOP‐1 and 75 μg hTGF‐β₃ in Matrigel^® matrix were compared with 20:1 binary applications, i.e. 25 μg hOP‐1 and 1.25 μg hTGF‐β₃. Morcellated fragments of autogenous rectus abdominis striated muscle were added to binary applications. Sixty days after implantation, the animals were killed and the operated tissues harvested en bloc. Undecalcified sections were studied by light microscopy, and regenerated tissue was assessed by measuring volume and height of newly formed alveolar bone and cementum. Results: The hOP‐1 and hTGF‐β₃ induced periodontal tissue regeneration and cementogenesis. Qualitative morphological analysis of binary applications showed clear evidence for considerable periodontal tissue regeneration. Quantitatively, the differences in the histomorphometric values did not reach statistical significance for the group size chosen for this primate study. The addition of morcellated muscle fragments did not enhance tissue regeneration. Binary applications showed rapid expansion of the newly formed bone against the root surfaces following fibrovascular tissue induction in the centre of the treated defects. Conclusion: Binary applications of hOP‐1and hTGF‐β₃ in Matrigel^® matrix in Class II furcation defects of P. ursinus induced substantial periodontal tissue regeneration, which was tempered, however, by the anatomy of the furcation defect model, which does not allow for the rapid growth and expansion of the synergistic induction of bone formation, particularly when additionally treated with responding myoblastic stem cells.     

The synergistic effects of IL-6/IL-17A promote osteogenic differentiation by improving OPG/RANKL ratio and adhesion of MC3T3-E1 cells on hydroxyapatite

Objective

In this study, we evaluated the potential role of IL-6 and/or IL-17A in regulating the OPG/RANKL (osteoprotegerin/receptor activator of nuclear factor kappa b ligand) system of murine osteoblast cell line (MC3T3-E1) cultured on hydroxyapatite (HA).