Polydopamine-Coated Silk Fiber with Controllable Length for Enhanced Hemostatic Application.

The development of highly effective hemostatic materials with high biocompatibility and outstanding performance is vital to the field of biomaterials. In this study, we develop a hemostatic fiber material that exhibits high biocompatibility and excellent performance. By incorporating polydopamine (PDA) into the alkaline treatment of silk fibroin (SF), we achieve PDA-coated SF fibers with lengths that can be controlled by the alkaline concentration. The PDA coating significantly enhances the hemostatic ability of the silk fibers and exhibits superior performance in both in vitro and ex vivo experiments. By performing animal studies involving a mouse liver puncture model and a femoral vein incision model, we demonstrate the remarkable hemostatic capability of the PDA-coated SF fibers, as evidenced by the lower blood loss compared to that of a commercial hemostat powder. These findings highlight the potential of applying a PDA-assisted alkaline treatment to SF fibers to efficiently create hemostatic fibers with controllable lengths, which would be promising candidates for clinical hemostatic applications.

Anti-Inflammatory Effect of Melittin on Porphyromonas Gingivalis LPS-Stimulated Human Keratinocytes.

Periodontitis is a chronic inflammatory disease that contributes to the destruction of the gingiva. Porphyromonas gingivalis (P. gingivalis) can cause periodontitis via its pathogenic lipopolysaccharides (LPS). Melittin, a major component of bee venom, is known to have anti-inflammatory and antibacterial effects. However, the role of melittin in the inflammatory response has not been elucidated in periodontitis-like human keratinocytes. Therefore, we investigated the anti-inflammatory effects of melittin on a P. gingivalis LPS (PgLPS)-treated HaCaT human keratinocyte cell line. The cytotoxicity of melittin was measured using a human keratinocyte cell line, HaCaT, and a Cell Counting Kit-8. The effect of melittin on PgLPS-induced inflammation was determined with Western blot, real-time quantitative PCT, and immunofluorescence. PgLPS increased the expression of toll-like receptor (TLR) 4 and proinflammatory cytokines, such as tumor necrosis factor-α (TNF-α), interleukin (IL)-6, IL-8, and interferon-γ (IFN-γ). Moreover, PgLPS induced activation of the nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB), extracellular signal-regulated kinase (ERK), and protein kinase B/Akt. Melittin also inhibited the expression of proinflammatory cytokines by suppressing the activation of the NF-κB signaling pathway, ERK, and Akt. Melittin attenuates the PgLPS-induced inflammatory response and could therefore be applied in the treatment of periodontitis for anti-inflammatory effects.

Tetraspanin 7 regulates sealing zone formation and the bone-resorbing activity of osteoclasts.

Tetraspanin family proteins regulate morphology, motility, fusion, and signaling in various cell types. We investigated the role of the tetraspanin 7 (Tspan7) isoform in the differentiation and function of osteoclasts. Tspan7 was up-regulated during osteoclastogenesis. When Tspan7 expression was reduced in primary precursor cells by siRNA-mediated gene knock-down, the generation of multinuclear osteoclasts was not affected. However, a striking cytoskeletal abnormality was observed: the formation of the podosome belt structure was inhibited and the microtubular network were disrupted by Tspan7 knock-down. Decreases in acetylated microtubules and levels of phosphorylated Src and Pyk2 in Tspan7 knock-down cells supported the involvement of Tspan7 in cytoskeletal rearrangement signaling in osteoclasts. This cytoskeletal defect interfered with sealing zone formation and subsequently the bone-resorbing activity of mature osteoclasts on dentin surfaces. Our results suggest that Tspan7 plays an important role in cytoskeletal organization required for the bone-resorbing function of osteoclasts by regulating signaling to Src, Pyk2, and microtubules.

PINK1 restrains periodontitis-induced bone loss by preventing osteoclast mitophagy impairment.

The oral colonization of periodontal pathogens onto gingival tissues establishes hypoxic microenvironment, often disrupting periodontal homeostasis in conjunction with oxidative stress. The association between reactive oxygen species (ROS) and osteolytic periodontitis have been suggested by recent studies. PTEN-induced kinase 1 (PINK1), a mitochondrial serine/threonine kinase, is an essential protein for mitochondrial quality control as it protects cells from oxidative stress by promoting degradation of damaged mitochondria through mitophagy. However, the pathophysiological roles of PINK1 in osteoclast-mediated bone loss have not been explored. Here we aimed to determine whether PINK1 plays a role in the regulation of osteoclastogenesis and alveolar bone resorption associated with periodontitis. C57BL/6 wild type (WT) and Pink1 knockout (KO) mice were subjected to ligature-induced periodontitis (LIP), and alveolar bones were evaluated by µCT-analysis and tartrate-resistant acid phosphatase (TRAP) staining. The µCT-analysis showed that bone volume fraction and travecular thickness were lower in Pink1 KO compared to WT mice. The number of TRAP-positive osteoclasts was markedly increased in the periodontal tissues of Pink1 KO mice with LIP. The genetic silencing or deletion of Pink1 promoted excessive osteoclast differentiation and bone resorption in vitro, as respectively indicated by TRAP staining and resorption pits on dentin slices. PINK1 deficiency led to mitochondrial instabilities as indicated by confocal microscopy of mitochondrial ROS, mitochondrial oxygen consumption rate (OCR) analysis, and transmission electron microscopy (TEM). Consequently, a significant increase in Ca2+-nuclear factor of activated T cells 1 (NFATc1) signaling was also found. On the other hand, restoration of mitophagy and autophagy by spermidine (SPD) treatment and the resolution of oxidative stress by N-acetyl-l-cysteine (NAC) treatment protected PINK1 deficiency-induced excessive generation of osteoclasts. Taken together, our findings demonstrate that PINK1 is essential for maintaining mitochondrial homeostasis during osteoclast differentiation. Therefore, targeting PINK1 may provide a novel therapeutic strategy for severe periodontitis with fulminant osteolysis.

Nasolacrimal duct obstruction after maxillary orthognathic surgery.

PURPOSE: To report cases of nasolacrimal duct obstruction (NLDO) after maxillary orthognathic surgery. MATERIALS AND METHODS: The authors reviewed the clinical manifestations, dacryocystographic images, and orbital computed tomographic scans of 10 patients who were diagnosed with NLDO after undergoing maxillary orthognathic surgery. RESULTS: Six of the 10 patients (60%) complained of epiphora immediately after the surgery. Bilateral (n = 2, 20%) or unilateral (n = 8, 80%) NLDO occurred in all patients involved in the study. Twelve eyes of 10 patients were examined, and dacryocystography showed that the obstruction was present in the distal ostium in 7 eyes (58.3%), the junction between the sac and duct in 3 eyes (25%), and the common canaliculus in 2 eyes (16.7%). Computed tomographic scans of all subjects showed that mucosal swelling and congestion around the distal NLD opening narrowed the space between the lateral nasal wall and the inferior turbinate of the affected side. Dacryocystorhinostomy was performed in 9 eyes (8 patients), with a success rate of 100%. CONCLUSIONS: The distal to proximal portion of the NLD can become obstructed after maxillary orthognathic surgery. This obstruction seems to be caused by secondary inflammatory changes associated with an indirect injury of the NLD. Therefore, clinicians should be aware of the possibility of NLDO after orthognathic surgery, which can be treated successfully with dacryocystorhinostomy.

Immunosuppressive biomaterial-based therapeutic vaccine to treat multiple sclerosis via re-establishing immune tolerance.

Current therapies for autoimmune diseases, such as multiple sclerosis (MS), induce broad suppression of the immune system, potentially promoting opportunistic infections. Here, we report an immunosuppressive biomaterial-based therapeutic vaccine carrying self-antigen and tolerance-inducing inorganic nanoparticles to treat experimental autoimmune encephalomyelitis (EAE), a mouse model mimicking human MS. Immunization with self-antigen-loaded mesoporous nanoparticles generates Foxp3+ regulatory T-cells in spleen and systemic immune tolerance in EAE mice, reducing central nervous system-infiltrating antigen-presenting cells (APCs) and autoreactive CD4+ T-cells. Introducing reactive oxygen species (ROS)-scavenging cerium oxide nanoparticles (CeNP) to self-antigen-loaded nanovaccine additionally suppresses activation of APCs and enhances antigen-specific immune tolerance, inducing recovery in mice from complete paralysis at the late, chronic stage of EAE, which shows similarity to chronic human MS. This study clearly shows that the ROS-scavenging capability of catalytic inorganic nanoparticles could be utilized to enhance tolerogenic features in APCs, leading to antigen-specific immune tolerance, which could be exploited in treating MS.

Machine learning to predict distal caries in mandibular second molars associated with impacted third molars.

Impacted mandibular third molars (M3M) are associated with the occurrence of distal caries on the adjacent mandibular second molars (DCM2M). In this study, we aimed to develop and validate five machine learning (ML) models designed to predict the occurrence of DCM2Ms due to the proximity with M3Ms and determine the relative importance of predictive variables for DCM2Ms that are important for clinical decision making. A total of 2642 mandibular second molars adjacent to M3Ms were analyzed and DCM2Ms were identified in 322 cases (12.2%). The models were trained using logistic regression, random forest, support vector machine, artificial neural network, and extreme gradient boosting ML methods and were subsequently validated using testing datasets. The performance of the ML models was significantly superior to that of single predictors. The area under the receiver operating characteristic curve of the machine learning models ranged from 0.88 to 0.89. Six features (sex, age, contact point at the cementoenamel junction, angulation of M3Ms, Winter's classification, and Pell and Gregory classification) were identified as relevant predictors. These prediction models could be used to detect patients at a high risk of developing DCM2M and ultimately contribute to caries prevention and treatment decision-making for impacted M3Ms.

Radiographic Predictors of Difficult Laryngoscopy in Acromegaly Patients.

BACKGROUND: Patients with acromegaly have a high risk of difficult laryngoscopy. However, clinical predictors, such as upper lip bite test or modified Mallampati class, show limited predictive performance for difficult laryngoscopy in such patients. In this retrospective study, we evaluated radiographic indices obtained from skull lateral x-ray and ostiomeatal unit computed tomography images to predict difficult laryngoscopy in acromegaly patients. MATERIALS AND METHODS: Data on demographics, preoperative serum levels of pituitary hormones, and radiographic indices were collected from 90 acromegaly patients that underwent transsphenoidal removal for pituitary tumor from January 2010 to December 2016. Difficult laryngoscopy was defined as Cormack-Lehane grade ≥III. RESULTS: Difficult laryngoscopy occurred in 21 (23%) patients. In univariate analysis, age and radiographic indices indicating tongue size, such as tongue area (TA) on ostiomeatal unit computed tomography, linear distance from the alveolar line of the mandible to the hyoid bone, and linear distance from the interior border of the mandible to the hyoid bone on skull lateral x-ray, were associated with difficult laryngoscopy. In multivariate analysis, age (odds ratio [95% confidence interval], 1.084 [1.037-1.190]; P=0.002) and TA (1.002 [1.000-1.003], P=0.014) were independent risk factors for difficult laryngoscopy. The area under the curve of the combined model of age and TA was 0.80. CONCLUSIONS: Old age and radiographic predictors indicating large tongue size (large TA, long alveolar line of the mandible to the hyoid bone and mandible to the hyoid bone) were associated with an increased rate of difficult laryngoscopy in acromegaly patients. Preoperative radiographic measurements of tongue size can be helpful for safe airway management in such patients.

Regional variation of bone tissue properties at the human mandibular condyle.

The temporomandibular joint (TMJ) bears different types of static and dynamic loading during occlusion and mastication. As such, characteristics of mandibular condylar bone tissue play an important role in determining the mechanical stability of the TMJ under the macro-level loading. Thus, the objective of this study was to examine regional variation of the elastic, plastic, and viscoelastic mechanical properties of human mandibular condylar bone tissue using nanoindentation. Cortical and trabecular bone were dissected from mandibular condyles of human cadavers (9 males, 54-96 years). These specimens were scanned using microcomputed tomography to obtain bone tissue mineral distribution. Then, nanoindentation was conducted on the surface of the same specimens in hydration. Plastic hardness (H) at a peak load, viscoelastic creep (Creep/Pmax), viscosity (η), and tangent delta (tan δ) during a 30 second hold period, and elastic modulus (E) during unloading were obtained by a cycle of indentation at the same site of bone tissue. The tissue mineral and nanoindentation parameters were analyzed for the periosteal and endosteal cortex, and trabecular bone regions of the mandibular condyle. The more mineralized periosteal cortex had higher mean values of elastic modulus, plastic hardness, and viscosity but lower viscoelastic creep and tan δ than the less mineralized trabecular bone of the mandibular condyle. These characteristics of bone tissue suggest that the periosteal cortex tissue may have more effective properties to resist elastic, plastic, and viscoelastic deformation under static loading, and the trabecular bone tissue to absorb and dissipate time-dependent viscoelastic loading energy at the TMJ during static occlusion and dynamic mastication.

Fabrication of monodisperse liposomes-in-microgel hybrid microparticles in capillary-based microfluidic devices.

This study introduces a drop-based microfluidic approach to physically immobilize liposomes in microgel (liposomes-in-microgel) particles. For this, we generate a uniform liposomes-in-water-in-oil emulsion in a capillary-based microfluidic device. Basically, we have investigated how the flow rate and flow composition affect generation of emulsion precursor drops in micro-channels. Then, the precursor emulsion drops are solidified by photo-polymerization. From characterization of hydrogel mesh sizes, we have figured out that the mesh size of the liposomes-in-microgel particles is bigger than that of bare microgel particles, since liposomes take space in the hydrogel phase. In our further study on drug releasing, we have observed that immobilization of liposomes in the microgel particles can not only remarkably retard drug releasing, but also enables a sustained release, which stems from the enhanced matrix viscosity of the surrounding hydrogel phase.

Rewiring carbon catabolite repression for microbial cell factory.

Carbon catabolite repression (CCR) is a key regulatory system found in most microorganisms that ensures preferential utilization of energy-efficient carbon sources. CCR helps microorganisms obtain a proper balance between their metabolic capacity and the maximum sugar uptake capability. It also constrains the deregulated utilization of a preferred cognate substrate, enabling microorganisms to survive and dominate in natural environments. On the other side of the same coin lies the tenacious bottleneck in microbial production of bioproducts that employs a combination of carbon sources in varied proportion, such as lignocellulose-derived sugar mixtures. Preferential sugar uptake combined with the transcriptional and/or enzymatic exclusion of less preferred sugars turns out one of the major barriers in increasing the yield and productivity of fermentation process. Accumulation of the unused substrate also complicates the downstream processes used to extract the desired product. To overcome this difficulty and to develop tailor-made strains for specific metabolic engineering goals, quantitative and systemic understanding of the molecular interaction map behind CCR is a prerequisite. Here we comparatively review the universal and strain-specific features of CCR circuitry and discuss the recent efforts in developing synthetic cell factories devoid of CCR particularly for lignocellulose- based biorefinery.