Mesenchymal Stem Cells for Optimizing Bone Volume at the Dental Implant Recipient Site

Inadequate bone volume at the implant recipient site presents a clinical challenge for many dental practitioners. To overcome these problems, several approaches have been developed and are currently used, including bone grafting strategies and distraction osteogenesis. Mesenchymal stem cells (MSCs) have gained their popularity within the last two decades, with regard to promising clinical results in improving the bone architecture at the implant recipient site. The aim of this chapter was to briefly outline the accessibility properties, differentiation capacities, isolation, and characterization of MSCs with regard to optimizing bone volume in dental implantology. Additionally, potential benefits and pitfalls are discussed in comparison with the conventional bone augmentation techniques

Lipid-Iron Nanoparticle with a Cell Stress Release Mechanism Combined with a Local Alternating Magnetic Field Enables Site-Activated Drug Release

Simple Summary A novel active release system magnetic sphingomyelin-containing liposome encapsulated with indocyanine green, fluorescent marker, or the anticancer drug cisplatin was evaluated. The liposomal sphingomyelin is a target for the sphingomyelinase enzyme, which is released by stressed cells. Thus, sphingomyelin containing liposomes behave as a sensitizer for biological stress situations. In addition, the liposomes were engineered by adding paramagnetic beads to act as a receiver of outside given magnetic energy. The enzymatic activity towards liposomes and destruction caused by the applied magnetic field caused the release of the content from the liposomes. By using these novel liposomes, we could improve the drug release feature of liposomes. The improved targeting and drug-release were shown in vitro and the orthotopic tongue cancer model in mice optical imaging. The increased delivery of cisplatin prolonged the survival of the targeted delivery group versus free cisplatin. Most available cancer chemotherapies are based on systemically administered small organic molecules, and only a tiny fraction of the drug reaches the disease site. The approach causes significant side effects and limits the outcome of the therapy. Targeted drug delivery provides an alternative to improve the situation. However, due to the poor release characteristics of the delivery systems, limitations remain. This report presents a new approach to address the challenges using two fundamentally different mechanisms to trigger the release from the liposomal carrier. We use an endogenous disease marker, an enzyme, combined with an externally applied magnetic field, to open the delivery system at the correct time only in the disease site. This site-activated release system is a novel two-switch nanomachine that can be regulated by a cell stress-induced enzyme at the cellular level and be remotely controlled using an applied magnetic field. We tested the concept using sphingomyelin-containing liposomes encapsulated with indocyanine green, fluorescent marker, or the anticancer drug cisplatin. We engineered the liposomes by adding paramagnetic beads to act as a receiver of outside magnetic energy. The developed multifunctional liposomes were characterized in vitro in leakage studies and cell internalization studies. The release system was further studied in vivo in imaging and therapy trials using a squamous cell carcinoma tumor in the mouse as a disease model. In vitro studies showed an increased release of loaded material when stress-related enzyme and magnetic field was applied to the carrier liposomes. The theranostic liposomes were found in tumors, and the improved therapeutic effect was shown in the survival studies.Peer reviewe

Analysis of Genes Related to Invadopodia Formation and CTTN in Oral Squamous Cell Carcinoma—A Systematic Gene Expression Analysis

Successful treatment for any type of carcinoma largely depends on understanding the patterns of invasion and migration. For oral squamous cell carcinoma (OSCC), these processes are not entirely understood as of now. Invadopodia and podosomes, called invadosomes, play an important role in cancer cell invasion and migration. Previous research has established that cortactin (CTTN) is a major inducer of invadosome formation. However, less is known about the expression patterns of CTTN and other genes related to it or invadopodia formation in OSCC during tumor progression in particular. In this study, gene expression patterns of CTTN and various genes (n = 36) associated with invadopodia formation were analyzed to reveal relevant expression patterns and give a comprehensive overview of them. The genes were analyzed from a whole genome dataset of 83 OSCC samples relating to tumor size, grading, lymph node status, and UICC (Union for Internatioanl Cancer Control). The data revealed significant overexpression of 18 genes, most notably CTTN, SRC (SRC proto-onocogene, non-receptor tyrosine kinase), EGFR (epidermal growth factor receptor), SYK (spleen associated tyrosine kinase), WASL (WASP like actin nucleation promotion factor), and ARPC2 (arrestin beta 1) due to their significant correlation with further tumor parameters. This study is one of the first to summarize the expression patterns of CTTN and related genes in a complex group of OSCC samples

Ultrastructural and Biochemical Modifications of Collagen from Tissue of Morbus Dupuytren Patients

Small angle X-ray diffraction and biochemical analyses were carried out on normal palmar aponeurosis and on tissue from patients suffering from Dupuytren contractures (MD). Pathological tissue exhibits a higher overall content of collagen III. Type I collagen extracted from pathological tissue has a melting point of 0.8°C higher than that of normal collagen. The only chemical differences compared to normal collagen.I are 50% overhydroxylation of IysyI residues and a reduced amount of diglycosylated hydroxylysine residues. Analysis of the electron density distribution inside the collagen repeating period of MD-samples reveals disordered molecular packing in MD samples compared to in normal collagen. The disorder, which is higher in the gap region, is considerably reduced upon stretching

Investigation of Topographical Alterations in Titanium-Zirconium-Alloy Implant Threads following Er:YAG Irradiation

The aim of the current experimental study was to comparatively assess the surface alterations in titanium and titanium-zirconium alloy implants in terms of thread pitch topography after irradiation with an Er:YAG laser, which is recommended in the literature for its sterilizing effect in the treatment of contaminated implant surfaces. Roxolid® and SLA® (Sand-blasted, Large-grit, Acid-etched) implants from Straumann® company with the same macro topography were investigated. The surface treatment was carried out using a wavelength of 2940 nm, 60 s irradiation time, a frequency of 10 Hz, and energies between 120 mJ and 250 mJ. The alterations were quantitatively analyzed by conducting roughness analysis via white light interferometry and qualitatively using SEM images. Roxolid® could particularly maintain its surface topography at a level of 160 mJ. At an energy level of 250 mJ, the surface properties of the pitch could be significantly altered for the first time. Compared to the Standard Plus dental implants studied, no distinct removal of the material from the surface was detected. The alloy properties of Roxolid® confirm the manufacturer’s statement in terms of stability and could offer advantages in peri-implantitis management if decontamination has been selected. However, as a part of a respective strategy, smoothening of a Roxolid® implant surface requires a significantly higher energy level compared to SLA-Standard® dental implants

Effects of probiotics, prebiotics, and synbiotics on mineral metabolism in ovariectomized rats — impact of bacterial mass, intestinal absorptive area and reduction of bone turn-over

Background: Defined prebiotics were shown to improve calcium balance and diminish bone loss. However, the effect of their combination with probiotics on gut ecology and bone metabolism has not yet been studied. We investigated whether the combination of a probiotic with a defined microbial strain results in improved bone mineralization, and whether this effect is associated with changes in gut ecology. Methods: Eighty ovariectomized adult rats were allocated to five groups: group 1, sham-operated (SHAM); group 2–5, ovariectomized (OVX). Semipurified diets containing 0.7% calcium and 0.5% phosphorus were fed for 16 weeks, group 1 and group 2 got no supplements, group 3 (PRO) was supplemented with a potential probiotic (Lactobacillus acidophilus NCC90), group 4 (PRE) with prebiotics (oligofructose + acacia gum) and group 5 (SYN) with synbiotics (probiotics + prebiotics). Results: Ovariectomy increased body weight and reduced bone weight, content of calcium, phosphorus and ash of bone, bone alkaline phosphatase (BAP), and bone structure. This was indicated by lower trabecular bone area, trabecular perimeter, and connectivity but higher epiphyseal breadth. Ovariectomy elevated the jejunal pH. The probiotic alone did not significantly affect bone mineralization and gut ecology. Rats on prebiotics had significantly higher amounts of cecal contents and lower pH in cecal and colonic contents. Their calcium balance tended to be increased (p < 0.1). Synbiotics reduced pH in different intestinal segments, significantly in cecum. They stimulated most the colonic absorption surface as indicated by colon weight. Only feeding synbiotics significantly prevented OVX-induced loss of calcium content in lumbar vertebrae (mg) with final values (mean ± SD) of 44.44 ± 2.94 (SHAM), 41.20 ± 4.59 (OVX), 41.63 ± 3.78 (PRO), 43.42 ± 3.07 (PRE), and 44.68 ± 2.28 (SYN). This effect was associated with higher counts of bifidobacteria in the short-term and Bacteroides in the long-term, and with a tendency for lower BAP with 128.7 ± 28.5 U/L vs. 155.3 ± 28.1 U/L in OVX (p < 0.1). Conclusion: SYN exerted a synergistic effect on bone mineralization, presumably due to changes in gut microbiota and ecology associated with large bowel digesta weight (most likely reflecting microbial mass) and with large bowel weight (reflecting absorptive area), while bone turnover tended to be reduced as indicated by BAP

A Bacteria and Cell Repellent Zwitterionic Polymer Coating on Titanium Base Substrates towards Smart Implant Devices

Biofouling and biofilm formation on implant surfaces are serious issues that more than often lead to inflammatory reactions and the necessity of lengthy post-operation treatments or the removal of the implant, thus entailing a protracted healing process. This issue may be tackled with a biocompatible polymeric coating that at the same time prevents biofouling. In this work, oxygen plasma-activated silanized titanium substrates are coated with poly(sulfobetaine methacrylate), a zwitterionic antibiofouling polymer, using photopolymerization. The characterization of polymer films includes FT-IR, AFM, and adhesion strength measurements, where adhesion strength is analyzed using a cylindrical flat punch indenter and water contact angle (WCA) measurements. Both cytotoxicity analysis with primary human fibroblasts and fluorescence microscopy with fibroblasts and plaque bacteria are also performed is this work, with each procedure including seeding on coated and control surfaces. The film morphology obtained by the AFM shows a fine structure akin to nanoropes. The coatings can resist ultrasonic and sterilization treatments. The adhesion strength properties substantially increase when the films are soaked in 0.51 M of NaCl prior to testing when compared to deionized water. The coatings are superhydrophilic with a WCA of 10° that increases to 15° after dry aging. The viability of fibroblasts in the presence of coated substrates is comparable to that of bare titanium. When in direct contact with fibroblasts or bacteria, marginal adhesion for both species occurs on coating imperfections. Because photopolymerization can easily be adapted to surface patterning, smart devices that promote both osseointegration (in non-coated areas) and prevent cell overgrowth and biofilm formation (in coated areas) demonstrate practical potential