Effect of cement gap and drill offset on the marginal and internal fit discrepancies of crowns designed with different tooth preparations.

AIM: The aim of the present study was to evaluate the effect of cement gap and drill offset on the marginal and internal fit discrepancies of crowns designed with different tooth preparations. MATERIALS AND METHODS: Five tooth preparations were constructed, and crowns with different cement gaps and drill offsets were obtained. Then, best-fit alignment was performed on the crowns with the corresponding tooth preparations, and the fit discrepancies were expressed by color-coded difference images and root mean square (RMS) values. The RMS values of each group were analyzed by the rank-based Scheirer-Ray-Hare test (α = 0.05). RESULTS: The color segments in the sharp line angles area of the Sharp line angles group changed significantly before and after the drill offset. The cement gap had a significant effect on the marginal, internal, or overall fit discrepancies of the five design groups (P < 0.001), while the drill offset had a significant effect on the marginal fit discrepancies of the Shoulder-lip group and the internal or overall fit discrepancies of the Sharp line angles group (P < 0.001). Additionally, the interaction effect between cement gap and drill offset was significant for the marginal fit discrepancies of the Shoulder-lip group and the internal or overall fit discrepancies of the Sharp line angles group (P < 0.01). CONCLUSIONS: The cement gap and drill offset had a significant adverse effect on the marginal or internal fit discrepancies of the crowns designed with the shoulder-lip and sharp line angles designs. Tooth preparation designs with intense curvature changes such as shoulder-lip and sharp line angles should be avoided clinically.

Comparative clinical evaluation of removable partial denture frameworks fabricated traditionally or with selective laser melting: A randomized controlled trial.

STATEMENT OF PROBLEM: The clinical efficacy of selective laser melting (SLM) for fabricating removable partial dentures (RPDs) is not well established. PURPOSE: The purpose of this clinical study was to compare the performance of SLM-fabricated frameworks with that of those fabricated via traditional lost wax casting. MATERIAL AND METHODS: A double-blind, randomized, crossover design was used to compare cobalt-chromium partial denture frameworks (n=29) fabricated by using SLM or traditional methods. The time taken for adjustments and the clinical fit and stability of the adjusted frameworks were appraised. The accuracy of the frameworks was assessed by measuring the space between the occlusal rest seat and the corresponding rest seat. Statistical comparisons between the 2 frameworks were carried out by using a linear mixed-effect model for repeated measurements (α=.05). RESULTS: Frameworks fabricated by using both SLM and traditional techniques had an acceptable fit based on subjective clinical evaluation. The overall mean ±standard deviation space between the occlusal rest and rest seat for SLM frameworks (273.7 ±44.5 µm) was comparable with that of traditional frameworks (242.2 ±44.5 µm). The clinical fit adjustment time, 7.76 ±6.43 minutes for SLM and 5.49 ±6.39 minutes for traditionally fabricated frameworks, was statistically similar (P=.067). CONCLUSIONS: Dentures fabricated via SLM and traditional techniques had comparable accuracy of fit and clinical fitting time.

Enhanced Influenza Immunity by Nasal Mucosal Administration of the TPGS-Modified Liposomal Vaccine.

Influenza infection is difficult to prevent, control, and treat because of rapid viral mutation, fast disease progression, and high mortality. Vaccination is the main means by which to prevent and control influenza, but effectiveness is limited in that poor cellular uptake and weak immunogenicity of vaccines provides less than optimal host protection. Liposomal influenza vaccines are a promising strategy to overcome these limitations and the use of liposomal immune modulators and intranasal administration of liposomal influenza vaccines may be a means by which to improve influenza protection. The cationic lipids, i.e., dimethyldioctadecylammonium (DDA), 1,2-dioctadecanoyl-sn-glycero-3-phosphocholine (DSPC), and D-α-tocopherol polyethylene glycol 1000 (TPGS) can form blank liposomes, which can incorporate influenza antigens to produce an influenza vaccine (DDA-DSPC-TPGS). Herein, this vaccine was shown to induce dendritic cell maturation, increase host cellular uptake of the vaccine, and enhance immune responses both in vitro and in vivo. The addition of TPGS, as an amphiphilic immune adjuvant, significantly reduced the toxicity of the DDA liposomal influenza vaccine. Further, the polyethylene glycol component and tocopherol structure of TPGS enhanced the cellular uptake of the vaccine by means of stealth properties and the capacity to inhibit cellular efflux. After nasal mucosal immunization, enhanced cellular uptake rates and abundant immune cells in the nasopharyngeal-associated lymphoid tissue promoted the production of immunoglobulin A, immunoglobulin G1, and interferon-γ, which in turn mediated a more robust immune response against influenza virus. In summary, the DDA-DSPC-TPGS influenza vaccine is a safe and effective means by which to activate the immune system. The results herein provide an effective strategy by which to overcome current difficulties associated with the prevention and treatment of influenza.

Elevated Expression of Cathepsin K in Periodontal Ligament Fibroblast by Inflammatory Cytokines Accelerates Osteoclastogenesis via Paracrine Mechanism in Periodontal Disease.

Cathepsin K (CTSK) is a cysteine protease that is mainly produced from mature osteoclasts and contributes to the destruction of connective tissues and mineralized matrix as a consequence of periodontal disease (PD). However, few studies have reported its regulatory role in osteoclastogenesis-supporting cells in inflammatory conditions. Here, we investigated the role of CTSK in osteoclastogenesis-supporting cells, focusing on the modulation of paracrine function. Microarray data showed that CTSK was upregulated in PD patients compared with healthy individuals, which was further supported by immunohistochemistry and qPCR analyses performed with human gingival tissues. The expression of CTSK in the osteoclastogenesis-supporting cells, including dental pulp stem cells, gingival fibroblasts, and periodontal ligament fibroblasts (PDLFs) was significantly elevated by treatment with inflammatory cytokines such as TNFα and IL-1ß. Moreover, TNFα stimulation potentiated the PDLF-mediated osteoclastogenesis of bone marrow-derived macrophages. Interestingly, small interfering RNA-mediated silencing of CTSK in PDLF noticeably attenuated the TNFα-triggered upregulation of receptor activator of nuclear factor kappa-B ligand (RANKL), macrophage colony-stimulating factor, and RANKL/osteoprotegerin ratio, thereby abrogating the enhanced osteoclastogenesis-supporting activity of PDLF. Collectively, these results suggest a novel role of CTSK in the paracrine function of osteoclastogenesis-supporting cells in periodontal disease.

Verapamil-containing silicone gel reduces scar hypertrophy.

A hypertrophic scar is a common dermal fibroproliferative lesion usually treated with topical silicone. Verapamil, a type of calcium channel blocker, is considered a candidate drug for the treatment of hypertrophic scars. Here, we report that the addition of verapamil to topical silicone gel enhances treatment outcomes of hypertrophic scars. Upon creation of hypertrophic scars with the rabbit ear model, varying concentrations of verapamil-added silicone gel (0.1, 1, and 10 mg/g) were applied daily for 28 days. After the animals were euthanised, microscopic measurement was performed for (a) scar elevation index (SEI), (b) fibroblast count, and (c) capillary count. On gross analysis, features of hypertrophic scars were significantly alleviated in the verapamil-added groups. On histologic examination, verapamil-added groups showed (a) reduced SEI (1.93 (1.79-2.67) for control vs 1.34 (1.21-1.51) for silicone only and 1.13 (1.01-1.65) for verapamil-added silicone), (b) fibroblast count 700.5 (599.5-838.5) for control, 613.25 (461-762.5) for silicone only, and 347.33 (182.5-527) for verapamil-added silicone), and (c) capillary formation (52 (35.5-96.5) for control, 46 (28-64.5) for silicone only, and 39.83(24-70) for verapamil-added silicone) (Kruskal-Wallis test, P < .05). On western blot, expression levels of collagen I protein was lower in the 1 mg/g and 10 mg/g verapamil-added silicone compared with control. Therefore, we suggest a therapeutic concentration of verapamil-added silicone gel of at least over 1 mg/g. Further study regarding maximally effective concentration and deeper insight into the mechanism of action should follow.

Cationic liposome codelivering PI3K pathway regulator improves the response of BRCA1-deficient breast cancer cells to PARP1 inhibition.

Although some progresses have been made in breast cancer therapy, effective treatment for BRCA1-deficient breast cancer remains to be a great challenge. It has been demonstrated that the PI3K pathway is inappropriately activated in BRCA1-deficient breast cancers which can be downregulated by microRNA 451 (miR-451). In addition, although PARP1 inhibitors showed relatively positive results in both preclinical and clinical studies, additional efforts to decrease drug resistance as well as reduce systematic toxicity need to be addressed. To this end, by encapsulating the miR-451 mimic and PARP1 inhibitor in the same cationic liposome, we examined the potential of enhancing the response of PARP1 inhibition on BRCA1-deficient breast cancer by regulating the PI3K pathway. Our results revealed that in BRCA1-deficient human breast cancer cell line, PARP1 inhibition resulted in DNA damage with viability decrease, G2/M arrest as well as apoptosis. In contrast, single PI3K inhibition induced G1 arrest along with retarded cell proliferation. However, it was noted that combination of PARP inhibitor and PI3K regulator could exert synergetic function to evidently decrease cell proliferation compared with PARP inhibition alone, which was also confirmed by in vivo antitumor assay using xenograft tumor models. Collectively, our results offer an alternative but superior strategy for the therapy of BRCA1-deficient human breast cancers which may benefit the clinical applications.

Switching Mechanisms of Nonvolatile Memory Devices Fabricated with a Polydopamine Layer.

Nonvolatile memory devices based on a polydopamine (PDA) layer were fabricated by using a dip-coating process. Atomic force microscopy images revealed that the PDA layer had a conformal surface. The energy dispersive X-ray data showed the atomic stoichiometry of nitrogen and carbon in the PDA layer. The capacitance-voltage (C-V) curves of the Al/PDA/n-Si memory devices at 300 K showed a hysteresis with a large flat band shift, indicating that the incomplete PDA layer acted as a charge storage in the memory device. The switching mechanisms for the writing and erasing processes for the Al/PDA/n-Si devices are described on the basis of the C-V results and the energy band diagrams.

Influence of bone marrow-derived mesenchymal stem cells pre-implantation differentiation approach on periodontal regeneration in vivo.

AIM: The implantation of bone marrow-derived mesenchymal stem cells (MSCs) has previously been shown successful to achieve periodontal regeneration. However, the preferred pre-implantation differentiation strategy (e.g. maintenance of stemness, osteogenic or chondrogenic induction) to obtain optimal periodontal regeneration is still unknown. This in vivo study explored which differentiation approach is most suitable for periodontal regeneration. MATERIALS AND METHODS: Mesenchymal stem cells were obtained from Fischer rats and seeded onto poly(lactic-co-glycolic acid)/poly(ɛ-caprolactone) electrospun scaffolds, and then pre-cultured under different in vitro conditions: (i) retention of multilineage differentiation potential; (ii) osteogenic differentiation approach; and (iii) chondrogenic differentiation approach. Subsequently, the cell-scaffold constructs were implanted into experimental periodontal defects of Fischer rats, with empty scaffolds as controls. After 6 weeks of implantation, histomorphometrical analyses were applied to evaluate the regenerated periodontal tissues. RESULTS: The chondrogenic differentiation approach showed regeneration of alveolar bone and ligament tissues. The retention of multilineage differentiation potential supported only ligament regeneration, while the osteogenic differentiation approach boosted alveolar bone regeneration. CONCLUSION: Chondrogenic differentiation of MSCs before implantation is a useful strategy for regeneration of alveolar bone and periodontal ligament, in the currently used rat model.

Synthesis, characterization and cytocompatibility of a degradable polymer using ferric catalyst for esophageal tissue engineering.

This study focused on the synthesis, characterization and cytocompatibility of a biodegradable polymer by the cross-linking from poly(ethylene glycol-co-lactide) dimethacrylate (PLEGDMA), polyethylene glycol diacrylate (PEGDA) and N-isopropylacrylamide, where PLEGDMA was synthesized by ring-opening oligomerization of poly(ethylene glycol) with different molecular weights (Mn = 400, 600, 1000, 2000 Da) and L-lactide using low toxic iron(III) acetylacetonate (Fe(acac)3) as the catalyst and subsequently being terminated with dimethacrylate. The product, PLEGDMA, was analyzed to confirm its chemistry using FTIR spectroscopy, (1)H NMR spectra and gel permeation chromatography etc. The thermodynamic properties, mechanical behaviors, surface hydrophilicity, degradability and cytotoxicity of the cross-linked product were evaluated by differential scanning calorimetry, tensile tests, contact angle measurements and cell cultures. The effects of reaction variables such as PEGDA content and reactants ratio were optimized to achieve a material with low glass transition temperature (Tg), high wettability and preferable mechanical characteristics. Using a tubular mould which has been patented in our group, a tubular scaffold with predetermined dimension and pattern was fabricated, which aims at guiding the growth and phenotype regulation of esophageal primary cells like fibroblast and smooth muscle cell towards fabricating tissue engineered esophagus in future.

The influence of electrospun fibre scaffold orientation and nano-hydroxyapatite content on the development of tooth bud stem cells in vitro.

In stem cell-based dental tissue engineering, the goal is to create tooth-like structures using scaffold materials to guide the dental stem cells. In this study, the effect of fiber alignment and hydroxyapatite content in biodegradable electrospun PLGA scaffolds have been investigated. Fiber orientation of the scaffolds was random or aligned in bundles. For scaffolds with prefabricated orientation, scaffolds were fabricated from PLGA polymer solution containing 0, 10 or 20 % nano-hydroxyapatite. The scaffolds were seeded with porcine cells isolated from tooth buds (dental mesenchymal, dental epithelial, and mixed dental mesenchymal/epithelial cells). Samples were collected at 1, 3 and 6 weeks. Analyses were performed for cell proliferation, ALP activity, and cell morphology. Fiber alignment showed an effect on cell orientation in the first week after cell seeding, but had no long-term effect on cell alignment or organized calcified matrix deposition once the cells reach confluency. Scaffold porosity was sufficient to allow migration of mesenchymal cells. Hydroxyapatite incorporation did not have a positive effect on cell proliferation, especially of epithelial cells, but seemed to promote differentiation. Concluding, scaffold architecture is important to mesenchymal cell morphology, but has no long-term effect on cell alignment or organized ECM deposition. nHA incorporation does have an effect on cell proliferation, differentiation and ECM production, and should be regarded as a bioactive component of dental bioengineered scaffolds.

Tumor-penetrating iRGD facilitates penetration of poly(floxuridine-ketal)-based nanomedicine for enhanced pancreatic cancer therapy.

Efficient intratumoral penetration is essential for nanomedicine to eradicate pancreatic tumors. Although nanomedicine can enter the perivascular space of pancreatic tumors, their access to distal tumor cells, aloof from the vessels, remains a formidable challenge. Here, we synthesized an acid-activatable macromolecular prodrug of floxuridine (FUDR)-poly(FUDR-ketal), engineered a micellar nanomedicine of FUDR, and intravenously co-administered the nanomedicine with the tumor-penetrating peptide iRGD for enhanced treatment of pancreatic tumor. A FUDR-derived mono-isopropenyl ether was synthesized and underwent self-addition polymerization to afford the hydrophobic poly(FUDR-ketal), which was subsequently co-assembled with amphiphilic DSPE-mPEG into the micellar nanomedicine with size of 12 nm and drug content of 56.8 wt% using nanoprecipitation technique. The acetone-based ketal-linked poly(FUDR-ketal) was triggered by acid to release FUDR to inhibit cell proliferation. In an orthotopic pancreatic tumor model derived from KPC (KrasLSL-G12D/+; Trp53LSL-R172H/+; Pdx1-Cre) cells that overexpress neuropilin-1 (NRP-1) receptor, iRGD improved penetration of FUDR nanomedicine into tumor parenchyma and potentiated the therapeutic efficacy. Our nanoplatform, along with iRGD, thus appears to be promising for efficient penetration and activation of acid-responsive nanomedicines for enhanced pancreatic cancer therapy.

Evaluation on Surface Characteristics, Accuracy, and Dimensional Stability of Tooth Preparation Dies Fabricated by Conventional Gypsum and 3D-Printed Workflows.

PURPOSE: To evaluate the surface characteristics, accuracy (trueness and precision), and dimensional stability of tooth preparation dies fabricated using conventional gypsum and direct light processing (DLP), stereolithography (SLA), and polymer jetting printing (PJP) techniques. MATERIALS AND METHODS: Gypsum preparation dies were replicated according to the reference data and imported into DLP, SLA, and PJP printers, and the test data were obtained by scanning after 0, 1, 3, 7, 14, 28, and 42 days. After analyzing the surface characteristics, a best-fit algorithm between the test and the reference data was used to evaluate the accuracy and dimensional stability of the preparation dies. The data were analyzed by one-way analysis of variance and Tukey test or Kruskal-Wallis H test (α = .05). RESULTS: Compared with the gypsum group (3.61 ± 0.59 µm), the root mean square error (RMSE) values of the SLA group (5.33 ± 0.48 µm) was rougher (P < .05), the PJP group (2.43 ± 0.37 µm) was smoother (P < .05), and the DLP group (2.92 ± 0.91 µm) had no significant difference (P > .05). For trueness, the RMSE was greater in the PJP (34.90 ± 4.91 µm) and SLA (19.01 ± 0.95 µm) groups than in the gypsum (16.47 ± 0.47 µm) group (P < .05), and no significant difference was found between the DLP (17.10 Å} 1.77 µm) and gypsum groups. Regarding precision, the RMSE ranking was gypsum = DLP = SLA < PJP group. The RMSE ranges in the gypsum, DLP, PJP, and SLA groups at different times were 6.79 to 8.86 µm, 5.44 to 10.17 µm, 10.16 to 11.28 µm, and 10.94 to 32.74 µm, respectively. CONCLUSION: Although gypsum and printed preparation dies showed statistically significant differences in surface characteristics, accuracy, and dimensional stability, all tooth preparation dies were clinically tolerated and used to produce fixed restorations.

Efficacy of a Virtual 3D Simulation-Based Digital Training Module for Building Dental Technology Students' Long-Term Competency in Removable Partial Denture Design: Prospective Cohort Study.

Background: Removable partial denture (RPD) design is crucial to long-term success in dental treatment, but shortcomings in RPD design training and competency acquisition among dental students have persisted for decades. Digital production is increasing in prevalence in stomatology, and a digital RPD (D-RPD) module, under the framework of the certified Objective Manipulative Skill Examination of Dental Technicians (OMEDT) system reported in our previous work, may improve on existing RPD training models for students. Objective: We aimed to determine the efficacy of a virtual 3D simulation-based progressive digital training module for RPD design compared to traditional training. Methods: We developed a prospective cohort study including dental technology students at the Stomatology College of Chongqing Medical University. Cohort 1 received traditional RPD design training (7 wk). Cohort 2 received D-RPD module training based on text and 2D sketches (7 wk). Cohort 3 received D-RPD module pilot training based on text and 2D sketches (4 wk) and continued to receive training based on 3D virtual casts of real patients (3 wk). RPD design tests based on virtual casts were conducted at 1 month and 1 year after training. We collected RPD design scores and the time spent to perform each assessment. Results: We collected the RPD design scores and the time spent to perform each assessment at 1 month and 1 year after training. The study recruited 109 students, including 58 (53.2%) female and 51 male (56.8%) students. Cohort 1 scored the lowest and cohort 3 scored the highest in both tests (cohorts 1-3 at 1 mo: mean score 65.8, SD 21.5; mean score 81.9, SD 6.88; and mean score 85.3, SD 8.55, respectively; P<.001; cohorts 1-3 at 1 y: mean score 60.3, SD 16.7; mean score 75.5, SD 3.90; and mean score 90.9, SD 4.3, respectively; P<.001). The difference between cohorts in the time spent was not statistically significant at 1 month (cohorts 1-3: mean 2407.8, SD 1370.3 s; mean 1835.0, SD 1329.2 s; and mean 1790.3, SD 1195.5 s, respectively; P=.06) but was statistically significant at 1 year (cohorts 1-3: mean 2049.16, SD 1099.0 s; mean 1857.33, SD 587.39 s; and mean 2524.3, SD 566.37 s, respectively; P<.001). Intracohort comparisons indicated that the differences in scores at 1 month and 1 year were not statistically significant for cohort 1 (95% CI -2.1 to 13.0; P=.16), while cohort 3 obtained significantly higher scores 1 year later (95% CI 2.5-8.7; P=.001), and cohort 2 obtained significantly lower scores 1 year later (95% CI -8.8 to -3.9; P<.001). Conclusions: Cohort 3 obtained the highest score at both time points with retention of competency at 1 year, indicating that progressive D-RPD training including virtual 3D simulation facilitated improved competency in RPD design. The adoption of D-RPD training may benefit learning outcomes.

Evaluation of the root dentin bond strength and intratubular biomineralization of a premixed calcium aluminate-based hydraulic bioceramic endodontic sealer.

PURPOSE: This study evaluated the dentin bonding strength and biomineralization effect of a recently developed premixed calcium aluminate-based endodontic sealer (Dia-Root Bio Sealer) in comparison with existing calcium silicate-based sealers. METHODS: The root canals of 80 mandibular premolars were filled with Dia-Root Bio Sealer, Endoseal MTA, EndoSequence BC Sealer, and AH Plus Bioceramic Sealer. Medial and apical specimens were then obtained by sectioning. The push-out bond strength was measured using the medial specimens, and the failure mode was recorded. Intratubular biomineralization in the apical specimens was analyzed using scanning electron microscopy and energy-dispersive X-ray spectroscopy (EDS). The data were analyzed using one-way analysis of variance followed by the Tukey test (P < 0.05). RESULTS: The push-out bond strength of Dia-Root Bio Sealer was significantly higher than that of the other tested materials, and a cohesive failure pattern was observed in all groups. Dia-Root Bio Sealer also exhibited a significantly higher degree of biomineralization than the other groups, and EDS analysis indicated that the biomineralized precipitates were amorphous calcium phosphate. CONCLUSION: The results of this study indicate that Dia-Root Bio Sealer has the potential to be used as an adequate root canal sealer due to its favorable bonding performance.

Virtual sketching-based dental anatomy module improves learners' abilities to use computer-aided design to create dental restorations and prostheses.

Dental anatomy education for dental technology students should be developed in alignment with digital dental laboratory practices. We hypothesized that a virtually assisted sketching-based dental anatomy teaching module could improve students' acquisition of skills essential for digital restoration design. The second-year dental technology curriculum included a novel virtual technology-assisted sketching-based module for dental anatomy education. Pre- and post-course assessments evaluated students' skill sets and knowledge bases. Computer-aided design (CAD) scores were analyzed after one year to assess how the skills students developed through this module impacted their subsequent CAD performance. Participants who undertook the dental sketching-based teaching module demonstrated significantly improved theoretical knowledge of dental anatomy, dental aesthetic perception, and spatial reasoning skills. A partial least squares structural equation model indicated that the positive effects of this module on subsequent CAD performance were indirectly mediated by dental aesthetic perception, spatial reasoning, and practice time. A virtually assisted sketching-based dental anatomy teaching module significantly improved students' acquisition of skills and knowledge and positively mediated dental technology students' CAD performance.

Enhanced periodontal tissue regeneration by periodontal cell implantation.

AIM: Due to a lack of regenerative potential, current treatments for periodontal defects do not always provide satisfactory clinical results. Previously, the implantation of a biomaterial scaffold-cell construct has been suggested as a clinically achievable approach. In this study, it was aimed to investigate the contribution of implanted periodontal ligament (PDL) cells to periodontal tissue regeneration. MATERIALS & METHODS: Gelatin sponges were seeded with green fluorescent protein (GFP) transfected PDL or gingival fibroblasts (GF) cells, and implanted into a surgically created rat intrabony periodontal defect model. After six weeks, decalcified maxillae were used for histomorphometrical and immunohistochemical analyses. RESULTS: After six weeks, animals that had received the PDL cells exhibited significantly more functional bone and ligament. Furthermore, there were remarkable differences in the distribution of the transplanted cells. Periodontal ligament cells were always located directly lining the newly regenerated areas. In contrast, GF cells dispersed over the whole defect area, and did not provide a favourable effect on the regeneration of the periodontal tissues. CONCLUSION: We concluded that PDL cells transplanted into a periodontal defect survive and favour regeneration of periodontium, possibly in a paracrine manner.

Drug content on anticancer efficacy of self-assembling ketal-linked dextran-paclitaxel conjugates.

Although polymer-drug conjugates (PDCs) show great promise as versatile drug delivery systems, no antitumor PDCs based on small-molecule drugs are currently on the market, partly because of the lack of validated design principles for PDCs. High drug content is thought to be essential for devising highly efficacious PDCs based on poorly soluble antitumor drugs, but this has not been well validated. Therefore, revisiting the relationship between drug content and PDC performance is vital. In this study, we synthesized four dextran-paclitaxel (PTX) conjugates (designated as DKPs) with different drug contents by linking dextran and PTX via an acid-responsive ketal, and we used the conjugates to construct self-assembled DKP nanoparticles (NPs) for antitumor therapy. We focused on how PTX content influenced the hydrolysis kinetics, cytotoxicity, cellular uptake and intracellular hydrolysis, pharmacokinetics, biodistribution, and antitumor efficacies of the DKP NPs. We found that DKP NPs with lower PTX content showed accelerated drug release and increased tumor accumulation, and consequently enhanced antitumor efficacy. In 4T1-Luc and Panc02-Luc cancer models, the NPs showed considerably improved therapeutic efficacy than the micellar formulation of PTX that is currently in clinical use. Our results indicate that DKP NPs with lower PTX content possess greater antitumor potential, and our findings offer new insights for the connection of drug content-formulation-bioactivity relationship in the rational design of PDC prodrugs.

Vasohibin-1 promotes osteoclast differentiation in periodontal disease by stimulating the expression of RANKL in gingival fibroblasts.

Vasohibin-1 (VASH1) is a key inhibitor of vascular endothelial growth factor-induced angiogenesis. Although the involvement of VASH1 in various pathological processes has been extensively studied, its role in periodontal disease (PD) remains unclear. We aimed to investigate the role of VASH1 in PD by focusing on osteoclastogenesis regulation. We investigated VASH1 expression in PD by analyzing data from the online Gene Expression Omnibus (GEO) database and using a mouse ligature-induced periodontitis model. The effects of VASH1 on osteoclast differentiation and osteoclastogenesis-supporting cells were assessed in mouse bone marrow-derived macrophages (BMMs) and human gingival fibroblasts (GFs). To identify the stimulant of VASH1, we used culture broth from Porphyromonas gingivalis (Pg), a periopathogen. The GEO database and mouse periodontitis model revealed that VASH1 expression was upregulated in periodontitis-affected gingival tissues, which was further supported by immunohistochemistry and qRT-PCR analyses. VASH1 expression was significantly stimulated in GFs after treatment with the Pg broth. Direct treatment with recombinant VASH1 protein did not stimulate osteoclast differentiation in BMMs but did contribute to osteoclast differentiation by inducing RANKL expression in GFs through a paracrine mechanism. Small interfering RNA-mediated silencing of VASH1 in GFs abrogated RANKL-mediated osteoclast differentiation in BMMs. Additionally, VASH1-activated RANKL expression in GFs was significantly suppressed by MK-2206, a selective inhibitor of AKT. These results suggest that Pg-induced VASH1 may be associated with RANKL expression in GFs in a paracrine manner, contributing to osteoclastogenesis via an AKT-dependent mechanism during PD progression.

Evaluation of Intraosseous Pressure during Pelvic Percutaneous Cement Injection: An In Vitro Study in Swine.

Background: A minimally invasive procedure for symptomatic pelvic bone metastasis is a feasible option for advanced cancer patients, and bone cement injection plays an essential role. Pulmonary embolism caused by thrombus, fat, or tumor emboli is a major complication related to bone cement injection, and increasing intraosseous pressure is a predisposing factor. This study aimed to quantify the degree of pressure change in the pelvic bone during percutaneous bone cement injection and investigate whether there is a significant decrease in intraosseous pressure when a decompressive route is additionally established. Methods: Bone cement injection into the acetabulum of swine pelvises by simulating the actual surgical procedure in terms of the injection method, bone cement, and surgical instruments was performed while recording the intraosseous pressure. Twenty swine pelvises were used and grouped into a decompression group and a non-decompression group. Bone cement injection and pressure measurement were conducted in the same way in both groups, but an additional decompressive route was established for each pelvis in the decompression group. Continuous variables were compared using the Mann-Whitney test. Results: The mean amount of injected bone cement was 19.8 mL and 20.3 mL and the mean speed of bone cement injection was 0.14 mL/sec and 0.12 mL/sec in the decompression group and the non-decompression group, respectively. The mean peak intraosseous pressures was 10.5 kPa with decompression and 37.8 kPa without decompression, and the difference was statistically significant (p < 0.01). Conclusions: Intraosseous pressure during bone cement injection into swine pelvises was similar to that during vertebroplasty or kyphoplasty. When the additional decompression route was established, the intraosseous pressure decreased to one third the level.

Virulence factors released from Porphyromonas gingivalis induce electrophysiological dysfunction in human pluripotent stem cell-derived cardiomyocytes.

Background/purpose: Periodontal disease development correlates with the occurrence of systemic diseases. The present study investigated the association between periodontal disease and the development of cardiac arrhythmia. Materials and methods: Human embryonic stem cell-derived cardiomyocytes (hESC-CMs) were treated with Porphyromonas gingivalis (Pg). Cardiotoxicity and electrophysiological properties of hESC-CMs were measured using the cell counting kit-8 assay and a multi-electrode array, respectively. Reverse-transcription-quantitative polymerase chain reaction (RT-qPCR) revealed the mRNA expression of S100 calcium binding protein A1 (S100A1), calsequestrin 2 (CASQ2), troponin I3 (TNNI3), myosin light chain 2 (MYL2), integrin subunit beta 1 (ITGB1), and cadherin 2 (CDH2) in hESC-CMs. Results: Treatment with Pg broth significantly decreased the beat period, field potential duration, spike amplitude, and conduction velocity without affecting the viability of hESC-CMs. In addition, the mRNA expression of CASQ2, TNNI3, and MYL2, which are all associated with calcium handling, were downregulated by Pg broth treatment. Conclusion: These findings indicate that Pg may induce cardiac arrhythmia mediated by virulence factors.