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One goal in biomaterials research is to limit the formation of connective tissue around the implant. Antiwetting surfaces are known to reduce ability of cells to adhere. Such surfaces can be achieved by special surface structures (lotus effect). Aim of the study was to investigate the feasibility for creating antiwetting surface structures on titanium and to characterize their effect on initial cell adhesion and proliferation. Titanium microstructures were generated using femtosecond- (fs-) laser pulses. Murine fibroblasts served as a model for connective tissue cells. Quantitative investigation of initial cell adhesion was performed using atomic force microscopy. Fluorescence microscopy was used for the characterization of cell-adhesion pattern, cell morphology, and proliferation. Water contact angle (WCA) measurements evinced antiwetting properties of laser-structured surfaces. However, the WCA was decreased in serum-containing medium. Initial cell adhesion to microstructured titanium was significantly promoted when compared with polished titanium. Microstructures did not influence cell proliferation on titanium surfaces. However, on titanium microstructures, cells showed a flattened morphology, and the cell orientation was biased according to the surface topography. In conclusion, antiwetting properties of surfaces were absent in the presence of serum and did not hinder adhesion and proliferation of NIH 3T3 fibroblasts. © 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part A, 2012. [ABSTRACT FROM AUTHOR]

Murine mesenchymal progenitors (C3H10T1/2) stably expressing bone morphogenic protein 2 (BMP2) and the constitutively active SMAD8ca, a member of the family of mediators transferring signals of TGF-ß/BMP growth factors undergo differentiation into cells with tendon and ligament morphology in vitro and in vivo. In addition, adenovirally modified progenitors expressing both Smad8ca and BMP2 generate entire ectopic tendon-bone insertions with an osteotendinous junction exhibiting a fibrocartilage enthesis. Adenovirally modified progenitors expressing SMADca alone develop ectopic tendons without bony elements. These systems were used to repair a partial rat achilles tendon defect. We also evaluated the capacity to target mesenchymal progenitors to degenerated cartilage surfaces. Chimeric receptors with the ScFv-collagen type II recognition domain as extracellular part and the transmembrane and cytoplasmic domains of BMP receptors type IA and II as signaling domains were hypothesized to initiate chondrogenic differentiation upon cartilage binding. Indeed, in murine C3H10T½ the presence of chimeric BMP-receptors is sufficient to induce a massive burst of chondrogenesis, which is dependent on the presence of both chimeric receptor types I and II expressed at a high level. Similarly, in a 3D culture system of human mesenchymal stem cells (MSCs), the combination of both chimeric receptors (II+IA) induces chondrogenic differentiation. Further studies will assess the therapeutic potential for these receptors to bring about cartilage regeneration upon cartilage-binding. [ABSTRACT FROM AUTHOR]

TAK1 (transforming growth factor-β-activated kinase1), a MAP3K with considerable sequence similarity to Raf-1 and MEKK-1, has been identified as a transforming growth factor-β/bone morphogenetic protein (BMP)activated cytosolic component of the MAPK pathways. In this investigation, the molecular interactions between TAK1 and Smad proteins were characterized as well as their influence on BMP-mediated mesenchymal cell differentiation along the osteogenic/chondrogenic pathway. In co-immunoprecipitations we found an interaction of TAK1 with all Smads tested, R-Smads Smads1-5, the co-Smad Smad4, and the inhibitory Smads (I-Smad6 and I-Smad7). Smad interaction with TAK1 takes place through their MH2 domain. This interaction is dependent on the presence of an active kinase domain in TAK1. TAK1 dramatically interferes with RSmad transactivation in reporter assays and affects subcellular distribution of Smad proteins. Activated TAK1 also interferes with BMP-dependent osteogenic development in murine mesenchymal progenitor cells (C3H10T½). A potential TAK1-mediated apoptosis process could be excluded for these cells. Both synergistic and interfering influences of TAK1 on BMP-mediated Smad-signaling have been reported previously. We suggest that TAK1 is a factor that is involved in the finetuning of BMP effects during osteogenic development. [ABSTRACT FROM AUTHOR]

Statement of Problem: The hydrophobic and bioinert nature of polyetheretherketone (PEEK) implants needs to be addressed for successful osseointegration., Purpose: The purpose of this in vitro study was to evaluate the osteoblast cell behavior on PEEK implant surfaces treated with airborne-particle abrasion using different grit size aluminum oxide (Al 2 O 3 ) particles., Material and Methods: Disk-shaped specimens (n=96) were prepared from medical grade PEEK rods and were distributed into 4 groups (n=24) of untreated PEEK (PEEK 0), airborne-particle abrasion using 50-μm Al 2 O 3 particles (PEEK 50), airborne-particle abrasion using 110-μm Al 2 O 3 particles (PEEK 110), and airborne-particle abrasion using 150-μm Al 2 O 3 particles (PEEK 150). The surface characteristics were assessed using water contact angle (WCA) measurements and scanning electron microscopy (SEM). MG-63 osteoblast cells were cultured, and the biocompatibility of PEEK was assessed using a CellTiter-blue cell viability assay and florescence staining at day 1, 3, and 7. The specimens were stained with Alizarin red to assess the osteoblast cell differentiation on day 10 and 14. The Levene test was used to test the homogeneity of variances. One-way and Welch ANOVA with post hoc corrections were used to assess the overall statistical significance of differences among the groups (α=.05)., Results: The lowest mean WCA was demonstrated in PEEK 150 (49.25 ±5.51) and the highest in PEEK 0 (89.14 ±4.24) (P<.001). SEM images of PEEK 150 illustrated a more complex structure with a large area of globular outcroppings throughout the surface. PEEK 150 showed the highest cell metabolic activity at each time point with florescence staining showing a substantial cell confluence at day 3 and 7. Although PEEK 150 did not show a significant increase in cell proliferation, the number of cells attached was significantly higher than other groups (P<.05). PEEK 110 and 150 also showed a substantial increase in the extent of mineralization., Conclusions: Airborne-particle abrasion using moderate Al 2 O 3 grit size (110- or 150-μm) improved the hydrophilicity and osteoblast cell behavior on PEEK implants., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

Purpose: Currently, the prevention of periodontal diseases focuses on mechanical removal of pathogenic biofilms combined with oral antiseptics as supportive chemical antibacterial control. Due to the risk of resistance development and side effects of existing antiseptics, the interest in alternative medicine with naturopathic treatment modalities is growing in dentistry. In the present study, the antibacterial effect of the naturopathic oral care product Repha OS and some of its derivatives, based on medicinal plant extracts and essential oils, with a specific focus on added sweeteners, was investigated on periodontal pathogenic and halitosis-associated bacteria., Materials and Methods: The antibacterial efficacy was investigated by agar dilution assay. The minimum inhibitory concentration (MIC) for the bacterial species Aggregatibacter actinomycetemcomitans, Fusobacterium nucleatum, Porphyromonas gingivalis, Prevotella intermedia and Solobacterium moorei was determined., Results: A concentration-dependent antibacterial effect on oral bacterial species by Repha OS and its derivatives was demonstrated. For the original product, the maximum MIC was 10% of the calculated test solution concentration in agar for all examined bacterial species. The removal of essential oils reduced the antibacterial efficacy, whereas the displacement or replacement of sweeteners had almost no effect., Conclusion: In addition to other individual effects of the ingredients, the results of this study show that an antibacterial effect of the naturopathic oral care product on the tested oral bacterial species was achieved in vitro. In vivo, the combination of this antibacterial effect with other properties of the various ingredients may be interesting for a holistic approach in preventive dentistry.

The clinical implementation of percutaneous implants is still limited owing to infections at the side of the stoma. In our concept, this issue is addressed by designing copolymer surface coatings possessing biocompatibility and antimicrobial activity to improve the maintenance of a physiological skin seal at the skin-implant interface. Different copolymers with surface-active phosphonate and antimicrobial cationic groups were designed. Thus, coated titanium samples were cultured with bacterial strains or fibroblasts, respectively. Antimicrobial impact was evaluated by imaging the reduction of bacterial adherence. Biocompatibility was displayed by fibroblast proliferation and morphology. A variety of copolymers of 4-vinylpyridine with vinylbenzylphosphonate or dimethyl(2-methacryloyloxy-ethyl) phosphonate were prepared by free radical polymerization. The optimized polymer coating (copolymer D) showed a reduction of adherent bacteria up to 95%, with only a slight reduction in the adherence of human fibroblasts compared with blank titanium controls. In this study, we demonstrate in vitro that polymer surface coatings can be simultaneously antimicrobial and biocompatible. We consider this to be a promising technology for the realization of a permanent aseptic percutaneous passage as needed for the advancement of osseointegrated limb prosthesis.

Stem cell biology, an emerging field of research, provides promising methods in vitro as well as in vivo in animal models which make speculation about a future application in human dentistry reasonable. The objective of this study was to review the literature of stem cell research concerning fields relevant for dentistry. In dentistry, different stem cells are discussed. Adult dental ectomesenchymal stem cells seem promising for future therapy. Human stem cells have been isolated from the dental pulp, exfoliated deciduous teeth, the periodontal ligament, the dental follicle and the dental papilla. Stem cell markers such as STRO-1 were used for the characterization and isolation of stem cells. Adult dental stem cells can differentiate into many dental components, such as dentin, periodontal ligament, cement and dental pulp tissue, but not into enamel.

Mutations in the receptor tyrosine kinase Ror2 account for Brachydactyly type B and Robinow Syndrome. We have identified two novel factors interacting with the Ror2 intracellular domain. TAK1 (TGF-beta activated kinase 1), a MAP3K, interacts with Ror2 and phosphorylates its intracellular carboxyterminal serine/thronine/proline-rich (STP) domain. This TAK1-dependent phosphorylation of Ror2 induces phosphorylation of tyrosine-residues including a MAPK-like TGY-motif. The TAK1-dependent phosphorylation is enhanced by a second cytosolic factor, PRTB, which interacts with Ror2 and with TAK1 as well. The TAK1-dependent Tyr-phosphorylation of Ror2 is not mediated by the Ror2 tyrosine kinase domain and seems predominantly triggered by cytosolic kinases. Wnt-ligand binding differentially controls the Ror2/TAK1 interaction. Wnt1-binding displaces TAK1 from Ror2 while Wnt3a and Wnt5a are unable to do so thus modifying TAK1's capacity to cause phosphorylation of Ror2. Ror2 seems to act as a Wnt co-receptor enhancing Wnt-dependent canonical pathways while Tyr- and Ser/Thr-phosphorylation of Ror2 negatively controls the efficiency of these pathways. We propose that the level of the Wnt-ligand-regulated phosphorylation by cytosolic factors determines whether Ror2 acts as a stimulator or as an inhibitor of canonical Wnt-signalling.