Polyetheretherketone (PEEK) is considered a potential orthopedic/dental material because of its excellent mechanical and chemical properties (e.g., similar elastic modulus to that of human bone). ...However, the poor bacteriostasis and anti-inflammatory and osseointegrative properties of bioinert PEEK impede its clinical application. We previously developed a facile and versatile surface modification method using dexamethasone plus minocycline-loaded liposomes (Dex/Mino liposomes) bonded by a mussel-inspired polydopamine coating, which effectively modulated cell inflammatory response and discouraged bacterial colonization in vitro. Herein, we report the application of this multifunctional surface modification method to improve bioinert PEEK, aimed at further studying the in vitro osteogenesis and in vivo properties of Dex/Mino liposome-modified PEEK to prevent bacterial contamination, attenuate the inflammatory response, and enhance ossification for physiologic osseointegration. Our study established that the Dex/Mino liposome-modified PEEK surface presented favorable stability and cytocompatibility. Compared with bare PEEK, improved osteogenic differentiation of human mesenchymal stem cells under both osteoinductive and osteoconductive conditions was found on the functionalized surface due to the liposomal Dex releasing. In vivo bacteriostasis assay confirmed that Mino released from the functionalized surface provided an effective antibacterial effect. Moreover, the subcutaneous foreign body reaction and beagle femur implantation models corroborated the enhanced anti-inflammatory and osteointegrative properties of the functionalized PEEK. Our findings indicate that the developed Dex/Mino liposome-modified PEEK with enhanced antibacterial, anti-inflammatory, and osseointegrative capacity has great potential as an orthopedic/dental implant material for clinical application.
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Decentralized exchanges (DEXs) allow parties to participate in financial markets while retaining full custody of their funds. However, the transparency of blockchain-based DEX in combination with the ...latency for transactions to be processed, makes market-manipulation feasible. For instance, adversaries could perform front-running - the practice of exploiting (typically non-public) information that may change the price of an asset for financial gain.In this work we formalize, analytically exposit and empirically evaluate an augmented variant of front-running: sandwich attacks, which involve front- and back-running victim transactions on a blockchain-based DEX. We quantify the probability of an adversarial trader being able to undertake the attack, based on the relative positioning of a transaction within a blockchain block. We find that a single adversarial trader can earn a daily revenue of over several thousand USD when performing sandwich attacks on one particular DEX - Uniswap, an exchange with over 5M USD daily trading volume by June 2020. In addition to a single-adversary game, we simulate the outcome of sandwich attacks under multiple competing adversaries, to account for the real-world trading environment.
The signaling cascade between nuclear factor-kappa B (NF-κB) and hypoxia-inducible factor-1α (HIF-1α) can be activated by proinflammatory M1 macrophages in rheumatoid arthritis (RA), which produces ...reactive oxygen species (ROS) and enhances M1 macrophage polarization, thus aggravating the development of RA. Therefore, an ROS-responsive artesunate prodrug micellar nanosystem for co-delivery of dexamethasone (DEX/HA-TK-ART micelles, abbreviated as DEX/HTA) was developed for synergistic inhibition of the HIF-1α/NF-κB cascade to regulate ROS scavenging and macrophage repolarization in RA combination therapy. DEX/HTA micelles displayed prolonged circulation in blood and efficiently co-delivered ART&DEX in the inflamed joints of adjuvant-induced arthritis (AIA) rats; moreover, they were specifically recognized and internalized into M1 macrophages through CD44 receptor-mediated endocytosis. ROS-responsive co-released ART&DEX then exerted a synergistic action to efficiently perform ROS scavenging and repolarization of M1 to M2 macrophages by inhibition of the HIF-1α/NF-κB cascade. The intravenous administration of DEX/HTA micelles into AIA rat models significantly alleviated inflammatory cell infiltration and repaired cartilage injury in the joint. Collectively, our study highlights the therapeutic potential of DEX/HTA micelles for treating RA through synergistic inhibition of the HIF-1α/NF-κB signaling cascade to regulate ROS scavenging and macrophage repolarization.
An ROS-responsive artesunate (ART) prodrug micellar nanosystem for co-delivering dexamethasone (DEX), abbreviated as DEX/HA-TK-ART micelle, was developed for synergistic cascade regulation of the HIF-1α/NF-κB pathway on ROS scavenging and macrophage repolarization in combination therapy for rheumatoid arthritis. The well-designed nanosystem showed prolonged circulation in blood and superior ART&DEX accumulation in the inflamed joints of AIA rats; moreover, the micelles were specifically internalized into M1 macrophages and co-released ART&DEX, subsequently leading to inhibition of the HIF-1α/NF-κB pathway for ROS scavenging and macrophage repolarization, thus generating synergistic anti-inflammatory effects in RAW 264.7 cells and AIA rats. The HIF-1α/NF-κB cascade regulation on ROS scavenging and macrophage repolarization based on ART&DEX combination with smart nanotechnology could serve as a promising approach for rheumatoid arthritis therapy.
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Human-induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) have emerged as a promising tool for disease modeling and drug development. However, hiPSC-CMs remain functionally immature, ...which hinders their utility as a model of human cardiomyocytes.
To improve the electrophysiological maturation of hiPSC-CMs.
On day 16 of cardiac differentiation, hiPSC-CMs were treated with 100 nmol/L triiodothyronine (T3) and 1 μmol/L Dexamethasone (Dex) or vehicle for 14 days. On day 30, vehicle- and T3 + Dex-treated hiPSC-CMs were dissociated and replated either as cell sheets or single cells. Optical mapping and patch-clamp technique were used to examine the electrophysiological properties of vehicle- and T3 + Dex-treated hiPSC-CMs. Compared to vehicle, T3 + Dex-treated hiPSC-CMs had a slower spontaneous beating rate, more hyperpolarized resting membrane potential, faster maximal upstroke velocity, and shorter action potential duration. Changes in spontaneous activity and action potential were mediated by decreased hyperpolarization-activated current (If) and increased inward rectifier potassium currents (IK1), sodium currents (INa), and the rapidly and slowly activating delayed rectifier potassium currents (IKr and IKs, respectively). Furthermore, T3 + Dex-treated hiPSC-CM cell sheets (hiPSC-CCSs) exhibited a faster conduction velocity and shorter action potential duration than the vehicle. Inhibition of IK1 by 100 μM BaCl2 significantly slowed conduction velocity and prolonged action potential duration in T3 + Dex-treated hiPSC-CCSs but had no effect in the vehicle group, demonstrating the importance of IK1 for conduction velocity and action potential duration.
T3 + Dex treatment is an effective approach to rapidly enhance electrophysiological maturation of hiPSC-CMs.
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•T3 + Dex treatment increases INa, IK1, IKr and IKs and reduces If in hiPSC-CMs.•T3 + Dex treatment shortens action potential in hiPSC-CMs.•T3 + Dex treatment increases conduction velocity in hiPSC-CM cell sheets.•T3 + Dex treatment enhances the electrophysiological maturation of hiPSC-CMs.
Backgrounds: Osteoactivin (OA) is a key regulator promoting bone marrow stromal cells osteogenesis progress, while Dexamethasone (Dex) could inhibit OA induced osteogenesis and lead to osteoporosis. ...miR-26b increased during BMSC osteogenesis but whether it participates in this progress is enigma. Osteogenesis is under regulation of canonical Wnt signaling pathway which could serve as potential target for miR-26b. It bears therapeutic potential if miR-26b could regulate osteogenesis and antagonize Dex induced Osteoporosis (OP).
Methods: BMSC were isolated from bone marrow of rats and induced for osteogenesis by OA administration. We detected miR-26b mRNA level together with osteogenesis related genes or Wnt signal pathway related genes by qRT-PCR. BMSC cells with miR-26b inhibitor or mimics revealed the effect of miR-26b on osteogenesis. The osteogenesis efficiency was detected by Alizarin Red staining and ALP activity. Protein level of canonical Wnt signal pathway and other proteins were detected by Western blot. The interaction between miR-26b and GSK3β was detected by dual luciferase reporter assay.
Results: We found that miR-26b was increased during OA induced BMSC osteogenesis. Inhibiting miR-26b could lead to osteogenesis inhibition while miR-26b mimics could promote this progress. The key regulator of Wnt signal pathway GSK3β is down-regulated when miR-26b was overexpressed, resulting in β-catenin activation. Since Dex could promote GSK3β expression and inhibit Wnt signal, miR-26b could also alleviate Dex induced osteogenesis inhibition.
Conclusion: Our findings indicate that miR-26b promoted BMSC osteogenesis by directly targeting GSK3β and activating canonical Wnt signal pathway, suggesting miR-26b might be serve as potential therapeutic candidate of osteoporosis.
The aim of this prospective, randomized, controlled, double-blinded pilot study was to determine the rates of post-traumatic osteoarthritis and assess joint space width in the presence or absence of ...a single intra-articular injection of corticosteroid after an acute, intra-articular distal radius fracture (DRF).
Forty patients received a single, intra-articular, radiocarpal joint injection of 4 mg of dexamethasone (DEX) (n = 19) or normal saline placebo (n = 21) within 2 weeks of a surgically or nonsurgically treated intra-articular DRF. The primary outcome measure was minimum radiocarpal joint space width (mJSW) on noncontrast computed tomography scans at 2 years postinjection. Secondary outcomes were obtained at 3 months, 6 months, 1 year, and 2 years postinjection and included Disabilities of the Arm, Shoulder, and Hand; Michigan Hand Questionnaire; Patient-Rated Wrist Evaluation; wrist range of motion; and grip strength.
At 2-year follow-up, there was no difference in mean mJSW between the DEX group (2.2 mm; standard deviation, 0.6; range, 1.4-3.2) and the placebo group (2.3 mm; standard deviation, 0.7; range, 0.9-3.9). Further, there were no differences in any secondary outcome measures at any postinjection follow-up interval.
Radiocarpal joint injection of corticosteroid within 2 weeks of an intra-articular DRF does not appear to affect the development of post-traumatic osteoarthritis within 2 years follow-up in a small pilot cohort.
Therapeutic II.
•A Fe-Mn bimetallic nanozyme (Dex-FeMnzyme) with robust oxidase-like activity was synthesized.•A colorimetric sensor was designed for TAC assay based on the oxidase-like activity of Dex-FeMnzyme.•The ...sensor was well applied to determine the TAC content in fruit and vegetable food.
The total antioxidant capacity (TAC) has become increasingly vital for evaluating antioxidant food quality in the field of healthcare. Herein, a convenient and sensitive method for TAC assay was proposed based on the absorbance difference of reaction systems between various antioxidants existed in food and Dex-FeMnzyme/oxTMB. Under the optimum condition, the limit of detection (LOD) of the colorimetric sensor was 1.17 μM with the linear concentration range from 1 μM to 30 μM. The analysis results demonstrated the excellent feasibility of practical application in fruit and vegetable food, which offered a new avenue for the establishment of colorimetric biosensors.
Glioblastoma (GBM) is a highly aggressive and heterogeneous form of brain cancer. Genotypic and phenotypic heterogeneity drives drug resistance and tumor recurrence. Combination chemotherapy could ...overcome drug resistance; however, GBM's location behind the blood-brain barrier severely limits chemotherapeutic options. Interstitial therapy, delivery of chemotherapy locally to the tumor site, via a biodegradable polymer implant can overcome the blood-brain barrier and increase the range of drugs available for therapy. Ideal drug candidates for interstitial therapy are those that are potent against GBM and work in combination with both standard-of-care therapy and new precision medicine targets. Herein we evaluated paclitaxel for interstitial therapy, investigating the effect of combination with both temozolomide, a clinical standard-of-care chemotherapy for GBM, and everolimus, a mammalian target of rapamycin (mTOR) inhibitor that modulates aberrant signaling present in >80% of GBM patients. Tested against a panel of GBM cell lines in vitro, paclitaxel was found to be effective at nanomolar concentrations, complement therapy with temozolomide, and synergize strongly with everolimus. The strong synergism seen with paclitaxel and everolimus was then explored in vivo. Paclitaxel and everolimus were separately formulated into fibrous scaffolds composed of acetalated dextran, a biodegradable polymer with tunable degradation rates, for implantation in the brain. Acetalated dextran degradation rates were tailored to attain matching release kinetics (~3% per day) of both paclitaxel and everolimus to maintain a fixed combination ratio of the two drugs. Combination interstitial therapy of both paclitaxel and everolimus significantly reduced GBM growth and improved progression free survival in two clinically relevant orthotopic models of GBM resection and recurrence. This work illustrates the advantages of synchronized interstitial therapy of paclitaxel and everolimus for post-surgical tumor control of GBM.
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Chronic wounds have become a serious global health issue. In this study, we investigated the effect of increasing fucoidan (FD) concentration on the characteristics of nanofibers and their wound ...healing potential at in vitro as well as in vivo level. The results showed that increasing FD content (0.25 to 1 %) led to an significant increase in nanofiber diameter (487.7 ± 125.39 to 627.9 ± 149.78 nm), entrapment efficiency (64.26 ± 2.6 to 94.9 ± 3.1 %), and water uptake abilities (436.5 ± 1.2 to 679.7 ± 11.3 %). However, the in vitro biodegradation profile decreased with an increase in FD concentration. Water vapor transmission rate analysis showed that it was within the standard range for all FD concentrations. Nanofibers with 1 % PVA/DX/FD exhibited slow-release behavior, suggesting prolonged FD availability at the wound site. In vivo studies in rats with full-thickness wounds demonstrated that applying 1 % FD-enriched PVA/DEX nanofibers significantly (p < 0.0001) improved mean wound area closure. These findings suggest that FD-enriched nanofibers have immense potential as a wound dressing material in future if explored further.
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