Recombinant human bone morphogenetic protein-2 (rhBMP-2) is one of the growth factors that may induce the formation of new bone. The aim was to determine the efficacy of low doses of rhBMP-2 for bone ...regeneration using a collagen sponge as a carrier. Three doses of rhBMP-2 (1.167, 0.117, and 0.039 mg/mL) were combined with an absorbable collagen sponge (ACS) as a delivery vehicle. The rhBMP-2/ACS implants were placed in the subcutaneous tissues of rat backs. X-ray microcomputed tomography (micro-CT) and histological analysis were used to evaluate bone formation. The samples treated with 1.167 mg/mL of rhBMP-2 showed greater bone formation than the samples treated with 0.117 mg/mL of rhBMP-2 four weeks after surgery. However, there was no evidence of bone formation in the samples that were treated with 0.039 mg/mL of rhBMP-2. It was found that rhBMP-2 was osteogenic even at one-tenth of its manufacturer’s recommended concentration (1.167 mg/mL), indicating its potential for clinical use at lower concentrations.
Neutrophil energy metabolism during phagocytosis has been previously reported, and adenosine triphosphate (ATP) plays a crucial role in endocytosis. Neutrophils are prepared by intraperitoneal ...injection of thioglycolate for 4 h. We previously reported a system established for measuring particulate matter endocytosis by neutrophils using flow cytometry. In this study, we utilized this system to investigate the relationship between endocytosis and energy consumption in neutrophils. A dynamin inhibitor suppressed ATP consumption triggered by neutrophil endocytosis. In the presence of exogenous ATP, neutrophils behave differently during endocytosis depending on ATP concentration. The inhibition of ATP synthase and nicotinamide adenine dinucleotide phosphate oxidase but not phosphatidylinositol-3 kinase suppresses neutrophil endocytosis. The nuclear factor kappa B was activated during endocytosis and inhibited by I kappa B kinase (IKK) inhibitors. Notably, IKK inhibitors restored endocytosis-triggered ATP consumption. Furthermore, data from the NLR family pyrin domain containing three knockout mice suggest that inflammasome activation is not involved in neutrophil endocytosis or concomitant ATP consumption. To summarize, these molecular events occur via endocytosis, which is closely related to ATP-centered energy metabolism.
Abstract Dental adhesives are designed to bond composite resins to enamel and dentin. Their chemical formulation determines to a large extent their adhesive performance in clinic. Irrespective of the ...number of bottles, an adhesive system typically contains resin monomers, curing initiators, inhibitors or stabilizers, solvents and sometimes inorganic filler. Each one of these components has a specific function. The aim of this article is to systematically review the ingredients commonly used in current dental adhesives as well as the properties of these ingredients. This paper includes an extensive table with the chemical formulation of contemporary dental adhesives.
Asian sand dust (ASD), a type of particulate matter (PM) found in Asia, can be transported to East Asia. We recently found that acute splenic inflammation is induced by ASD in mouse models. In this ...study, we examined the effect of sub‐chronic ASD exposure on mouse immune cells. Mice were intratracheally administered ASD once every 2 weeks for 8 weeks and killed 24 hours after the final administration. Wild‐type (WT) mice showed increased cell viability after ASD administration. In contrast, ASD administration induced splenocyte activation in toll‐like receptor (TLR)2−/−, but not TLR4−/− mice. Furthermore, concanavalin A‐induced interleukin‐2 production increased after ASD administration in WT and TLR2−/− mice, but not in TLR4−/− or myeloid differentiation factor (MyD)88−/− mice. Immunoblotting demonstrated that nuclear factor κB (NF‐κB) was activated in WT mice, but not in TLR4−/− or MyD88−/− mice. The NF‐κB‐dependent gene products CDK2 and intercellular cell adhesion molecule‐1 were upregulated upon ASD administration in WT mice, but not in TLR4−/− or MyD88−/− mice. Furthermore, the particles themselves, rather than particle constituents, activated NF‐κB in CD4‐positive cells through the TLR4 or MyD88 pathway. Taken together, these results indicate that particle‐induced splenic inflammation occurs via TLR4‐MyD88 signaling.
Exposure to ambient Asian sand dust (ASD) is associated with serious adverse health effects. We investigated the splenic response in mice administered ASD. ASD enhanced mitogen‐induced immune responses and activated nuclear factor κB. However, ASD administration did not enhance splenocyte activation in toll‐like receptor 4−/− or myeloid differentiation factor 88−/− mice. Our findings indicate that ASD particles themselves, rather than particle constituents, induced splenic inflammation via toll‐like receptor 4‐myeloid differentiation factor signaling.
Certain dentin hypersensitivity treatment materials include oxalic acid to coat dentin surfaces with minerals, while certain organic acids possess a remineralization effect. Herein, an organic acid ...that inhibits the demineralization and coating of root surfaces was evaluated. Specimens were produced using five non-carious extracted bovines. Four different acids were used: oxalic acid (OA), malonic acid (MA), polyacrylic acid (PA), and succinic acid (SA). Each acid was applied to the root surface and washed using distilled water or a remineralization solution, and the surface was observed using scanning electron microscopy (SEM). All the surfaces of each specimen, barring the polished surface, were covered with wax and immersed in an automatic pH cycling system for two weeks. Dentin demineralization was analyzed using transverse microradiography (TMR) before and after pH cycling. SEM analysis demonstrated that the three acid groups demineralized the dentin surface, whereas the OA group generated crystals covering the dentin surface, even in a distilled water environment. TMR analysis revealed that the OA groups showed significantly lower integrated mineral loss compared with the other groups, even in the distilled water environment. The results suggest that OA generates insoluble calcium oxalate crystals on the dentin and suppresses demineralization even under low saliva conditions.
Abstract Objective The functional monomer 10-MDP has been considered as one of the best performing functional monomers for dental adhesives. Different adhesives containing 10-MDP are commercially ...available, among which many so-called ‘universal’ adhesives. We hypothesize that the quality of the functional monomer 10-MDP in terms of purity may affect bonding performance. Methods We therefore characterized three different 10-MDP versions (10-MDP_KN provided by Kuraray Noritake; 10-MDP_PCM provided by PCM; 10-MDP_DMI provided by DMI) using NMR, and analyzed their ability to form 10-MDP_Ca salts on dentin using XRD. The ‘immediate’ and ‘aged’ micro-tensile bond strength (μTBS) to dentin of three experimental 10-MDP primers was measured. The resultant interfacial adhesive-dentin ultra-structure was characterized using TEM. Results NMR disclosed impurities and the presence of 10-MDP dimer in 10-MDP_PCM and 10-MDP_DMI. 10-MDP_PCM and 10-MDP_DMI appeared also sensitive to hydrolysis. 10-MDP_KN, on the contrary, contained less impurities and dimer, and did not undergo hydrolysis. XRD revealed more intense 10-MDP_Ca salt deposition on dentin induced by 10-MDP_KN. The adhesive based on the experimental 10-MDP_KN primer resulted in a significantly higher ‘immediate’ bond strength that remained stable upon aging; the μTBS of the experimental 10-MDP_PCM and 10-MDP_DMI adhesives significantly dropped upon aging. TEM revealed thicker hybridization and more intense nano-layering for 10-MDP_KN. Significance It was concluded that primer impurities and the presence of 10-MDP dimer affected not only hybridization, but also reduced the formation of 10-MDP_Ca salts and nano-layering. 10-MDP in a high purity grade is essential to achieve durable bonding.
Osteochondral injuries remain difficult to repair. We developed a novel photo-cross-linkable furfurylamine-conjugated gelatin (gelatin-FA). Gelatin-FA was rapidly cross-linked by visible light with ...Rose Bengal, a light sensitizer, and was kept gelled for 3 weeks submerged in saline at 37°C. When bone marrow-derived stromal cells (BMSCs) were suspended in gelatin-FA with 0.05% Rose Bengal, approximately 87% of the cells were viable in the hydrogel at 24 h after photo-cross-linking, and the chondrogenic differentiation of BMSCs was maintained for up to 3 weeks. BMP4 fusion protein with a collagen binding domain (CBD) was retained in the hydrogels at higher levels than unmodified BMP4. Gelatin-FA was subsequently employed as a scaffold for BMSCs and CBD-BMP4 in a rabbit osteochondral defect model. In both cases, the defect was repaired with articular cartilage-like tissue and regenerated subchondral bone. This novel, photo-cross-linkable gelatin appears to be a promising scaffold for the treatment of osteochondral injury.
•PM endocytosis by differentiated HL-60 was inhibited by dynamin and MEK inhibitors.•MEK inhibitor inhibited differentiation of ATRA-HL to neutrophils.•Endocytosis of PM by neutrophils activated MAPK ...ERK and p38.•TNF-α and IL-8 were produced after LPS or PM treatment by differentiated HL-60.•ROS production was enhanced after PM treatment of DMSO-HL.
Reports show that particulate matter (PM) is related to respiratory and cardiovascular diseases. We previously reported the biological effects of PM in vivo and the endocytosis of PM by primary neutrophils from mice. Cell lines can be used to elucidate the mechanism underlying immune responses in detail; however, information is limited regarding the functions of neutrophils after PM exposure. Here, we investigated the immune response of primary neutrophils and dimethyl sulfoxide (DMSO)- and all-trans retinoic acid (ATRA)-differentiated HL-60 (neutrophil-like) cells to PM. We showed that endocytosis by ATRA-HL cells was enhanced compared to that by DMSO-HL cells and that endocytosis in both cells was inhibited by dynamin inhibitors. A MEK inhibitor, but not p38 or JNK inhibitors, inhibited endocytosis. The MEK inhibitor also inhibited the differentiation of ATRA-HL cells to neutrophils. We identified that endocytosis of PM by neutrophils activated the MAPK ERK and p38 pathways. DMSO-HL and ATRA-HL cells both produced TNF-α and IL-8 after lipopolysaccharide (LPS) or PM treatment, whereas non-differentiated HL-60 cells did not. MCP-1 production was enhanced in DMSO-HL cells after LPS or PM treatment, whereas it was high in ATRA-HL cells. Reactive oxygen species (ROS) production was enhanced after PM treatment to DMSO-HL cells. Further, extracellular extracts promoted endocytosis. The MEK inhibitor also reduced the production of TNF-α, IL-8, and MCP-1. Taken together, ERK activation is key for both differentiation and endocytosis, and DMSO-HL cells at day 6 can serve as a model of inflammatory neutrophils, such as bronchus neutrophils, and a good tool to analyze the molecular events involved in immune responses to PM.
The mechanisms of ectopic calcification in inflammatory diseases are poorly understood. We investigated the effects of inflammatory cytokines on the mechanisms of calcification in human adipose ...tissue-derived mesenchymal stem cells (hADSCs).
The effects of inflammatory cytokines were evaluated using hADSCs cultured in osteoblast induction medium. mRNA expression was measured by real-time PCR and protein levels were measured by western blotting. Cell mineralization was evaluated by Alizarin Red S staining.
In hADSCs, administration of IL-6/soluble IL-6 receptor (sIL-6R), TNF or IL-1β accelerated calcification through enhanced expression of an osteoblast differentiation marker, runt-related transcription factor 2 (RUNX2). IL-6/sIL-6R had the greatest effect. The transcription of mRNA for receptor tyrosine kinase-like orphan receptor 2 (ROR2), involved in the non-canonical wingless-type (WNT) MMTV integration site pathway, was increased, while β-catenin expression, an essential factor in the canonical WNT signalling pathway for osteoblast differentiation, did not change. Suppression of signal transducer and activator of transcription 3 (STAT3), but not STAT1, by small interfering RNA (siRNA) exerted a strong inhibitory effect on RUNX2 and ROR2 expression, and inhibited accelerated calcification.
IL-6/sIL-6R stimulation accelerated the ROR2/WNT5A pathway in hADSCs in a STAT3-dependent manner, resulting in augmented calcification. These results suggest that the mechanisms of ectopic calcification accelerated by IL-6 in hADSCs may be involved in chronic inflammatory tissues and that IL-6 inhibitors may be beneficial in the treatment of ectopic calcification in inflammatory diseases.
Although decayed/fractured teeth can be reconstructed minimally invasively and nearly invisibly using adhesive technology, the clinical longevity of dental composite restorations is still too short. ...Water sorption is thought to be the principal cause of destabilization of the biomaterial-tooth bond. However, the actual mechanisms of interfacial degradation are far from understood. Here we report how nano-controlled molecular interaction at the biomaterial-hard tissue interface can improve bond durability. The use of functional monomers with a strong chemical affinity for the calcium in hydroxyapatite is essential for long-term durability. Correlative X-ray diffraction and solid-state nuclear magnetic resonance disclosed a time-dependent molecular interaction at the interface with stable ionic bond formation of the monomer to hydroxyapatite competing in time with the deposition of less stable calcium phosphate salts. The advanced tooth-biomaterial interaction model gives not only an insight into the mechanisms of bond degradation, but also provides a basis to develop functional monomers for more durable tooth reconstruction.
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