Light and Magnetism Orchestrating Aquatic Pollutant-Degradation Robots in Programmable Trajectories

Interfacial floating robots have promising applications in carriers, environmental monitoring, water treatment, and so on. Even though, engineering smart robots with both precisely efficient navigation and elimination of water pollutants in long term remains a challenge, as the superhydrophobicity greatly lowers resistance for aquatic motion while sacrificing chemical reactivity of the surface. Here, a pollutant-removing superhydrophobic robot integrated with well-assembled iron oxide-bismuth sulfide heterojunction composite minerals, which provide both light and magnetic propulsion, and the ability of catalytic degradation, is reported. The motion velocity of the robot reaches up to 51.9 mm s-1 within only 300 ms of acceleration under the orchestration of light, and brakes rapidly (≈200-300 ms) once turn off the light. And magnetism extends the robot to work in broad range of surface tensions in any programmable trajectory. Besides, purification of polluted water is efficiently achieved in situ and the degradation efficiency exhibits eightfold enhancements under the effect of light-triggered photothermal behavior coupled with magnetic induction, overcoming the dilemma of efficient motion with catalytic superhydrophobicity. This strategy developed here provides guidelines for the explorations of high-performance smart devices.

A Drop-By-Drop Self-Assembled All-Natural Hydrogel as a Desensitizer for Rapid and Enduring Management of Dentin Hypersensitivity

Dentin hypersensitivity (DH) is a prevalent dental condition arising from the exposure of dentin tubules (DTs), leading to discomfort upon external stimuli. However, achieving swift and profound occlusion of these exposed DTs for immediate and enduring relief remains challenging due to the intricate dentin structure and oral environment. Herein, a pioneering and facile drop-by-drop strategy involving an in situ generated natural supramolecular hydrogel formed by self-assembling silk fibroin (SF) and tannic acid (TA) within the narrow DT space is proposed. When SF and TA aqueous solutions are applied successively to exposed dentin, they penetrate deeply within DTs and coassemble into compact gels, robustly adhering to DT walls. This yields a rapid and compact occlusion effect with an unprecedented depth exceeding 250 µm, maintaining stable occlusion efficacy even under rigorous in vitro and in vivo erosion and friction conditions for no less than 21 days. Furthermore, the biocompatibility and effective occlusion properties are verified through cell studies in simulated oral settings and an in vivo rabbit model. This study, for the first time, demonstrates the translational potential of hydrogel-based desensitizers in treating DH with prompt action, superior occlusion depth and enduring treatment benefits, holding promise as clinical-friendly restorative solutions for delicate-structured biosystems.

The application of a multi-component reaction peptide as a model regenerative active to enhance skin wound-healing postlaser procedure in a double-blinded placebo-controlled clinical trial

INTRODUCTION

Esthetic procedures are currently among the most effective options for consumers seeking to correct aging signs such as fine lines, wrinkles, and skin tone unevenness. Currently, there is a scientific need for an adjunct active to be paired with esthetic procedures to encourage wound recovery and address postprocedure pigmentation concerns.

OBJECTIVE

Toward that goal, this study assessed the efficacy of a peptide created from a multi-component reaction (multi-component peptide, MCP) as a model active for postprocedure care and evaluated its ability to promote skin healing in an ablative laser-induced wound model on the forearm.

METHODS

The mechanism of action of MCP was investigated using tubo assays, 2D melanocyte, and fibroblast cultures, reconstructed skin equivalents, and ex vivo skin explants. The MCP formula and the clinical benchmark formula of Aquaphor were assessed head-to-head by applying the products topically in an ablative laser-induced wound model (n = 20 subjects). The promotion of wound healing was evaluated by the investigator assessment of epithelial confluence, crusting or scabbing, general wound appearance, erythema, and edema.

RESULTS

MCP was determined to be beneficial to postprocedure skin recovery and healing by four main mechanisms of action: barrier repair as determined in an ex vivo tape-stripping model, reduction of inflammation and postinflammatory hyperpigmentation, reduction of elastase activity, and stimulation of fibroblast through the mTOR pathway. The formula containing 10% MCP enhanced the kinetics of epithelial confluence and improvement of the crusting or scabbing appearance of the laser-generated wounds in a laser-induced mini-zone wound healing study on the forearm.

CONCLUSION

This study demonstrates the use of MCP as a proof of concept regenerative active that when incorporated into an optimized postprocedure skincare formula can improve skin healing and enhance the appearance of skin after injury with relevance to ablative aesthetic procedures.

Hydrogel-Based Biosensors for Bacterial Infections

Hydrogels are known to have the advantages such as good biodegradability, biocompatibility, and easy functionalization, making them ideal candidates for biosensors. Hydrogel-based biosensors that respond to bacteria-induced microenvironmental changes such as pH, enzymes, antigens, etc., or directly interact with bacterial surface receptors, can be applied for early diagnosis of bacterial infections, providing information for timely treatment while avoiding antibiotic abuse. Furthermore, hydrogel biosensors capable of both bacteria diagnosis and treatment will greatly facilitate the development of point-of-care monitoring of bacterial infections. In this review, the recent advancement of hydrogel-based biosensors for bacterial infection is summarized and discussed. First, the biosensors based on pH-sensitive hydrogels, bacterial-specific secretions-sensitive hydrogels, and hydrogels directly in contact with bacterial surfaces are presented. Next, hydrogel biosensors capable of detecting bacterial infection in the early stage followed by immediate on-demand treatment are discussed. Finally, the challenges and future development of hydrogel biosensors for bacterial infections are proposed.

Bioinspired Multiscale Mineralization: From Fundamentals to Potential Applications

The wondrous and imaginative designs of nature have always been an inexhaustible treasure trove for material scientists. Throughout the long evolutionary process, biominerals with hierarchical structures possess some specific advantages such as outstanding mechanical properties, biological functions, and sensing performances, the formation of which (biomineralization) is delicately regulated by organic component. Provoked by the subtle structures and profound principles of nature, bioinspired functional minerals can be designed with the participation of organic molecules. Because of the designable morphology and functions, multiscale mineralization has attracted more and more attention in the areas of medicine, chemistry, biology, and material science. This review provides a summary of current advancements in this extending topic. The mechanisms underlying mineralization is first concisely elucidated. Next, several types of minerals are categorized according to their structural characteristic, as well as the different potential applications of these materials. At last, a comprehensive overview of future developments for bioinspired multiscale mineralization is given. Concentrating on the mechanism of fabrication and broad application prospects of multiscale mineralization, the hope is to provide inspirations for the design of other functional materials.

Natural Underwater Bioadhesive Offering Cohesion Modulation via Hydrogen Bond Disruptor: A Highly Injectable and in Vivo Stable Remedy for Gastric Ulcer Resolution

Injectable bioadhesives are attractive for managing gastric ulcers through minimally invasive procedures. However, the formidable challenge is to develop bioadhesives that exhibit high injectability, rapidly adhere to lesion tissues with fast gelation, provide reliable protection in the harsh gastric environment, and simultaneously ensure stringent standards of biocompatibility. Here, a natural bioadhesive with tunable cohesion is developed based on the facile and controllable gelation between silk fibroin and tannic acid. By incorporating a hydrogen bond disruptor (urea or guanidine hydrochloride), the inherent network within the bioadhesive is disturbed, inducing a transition to a fluidic state for smooth injection (injection force <5 N). Upon injection, the fluidic bioadhesive thoroughly wets tissues, while the rapid diffusion of the disruptor triggers instantaneous in situ gelation. This orchestrated process fosters the formed bioadhesive with durable wet tissue affinity and mechanical properties that harmonize with gastric tissues, thereby bestowing long-lasting protection for ulcer healing, as evidenced through in vitro and in vivo verification. Moreover, it can be conveniently stored (≥3 m) postdehydration. This work presents a promising strategy for designing highly injectable bioadhesives utilizing natural feedstocks, avoiding any safety risks associated with synthetic materials or nonphysiological gelation conditions, and offering the potential for minimally invasive application.

[Study on formulation and revision of detection methods of "Standards for indoor air quality (GB/T 18883-2022)" in China]

The formulation and revision of the detection methods of indoor air quality standards is an important, rigorous and delicate endeavor. This paper introduced the formulation and revision of the detection methods of the standards for indoor air quality (GB/T 18883-2022), focusing on the revision process, revision principles, main adjustments and technical points of some key indicators to facilitate users to better understand and apply the detection methods in standards for indoor air quality (GB/T 18883-2022).

[Study on formulation and revision of standard limits for total bacteria count in "Standards for indoor air quality（GB/T 18883-2022）" in China]

The total bacteria count has been attracting attention as an important pollutant in indoor air, and its standard limit was tightened to 1500 CFU/m3 in "Standards for indoor air quality (GB/T 18883-2022)".The technical contents related to the determination of the indoor air standard limits for total bacteria count were analyzed and studied, including the environmental existence level, exposure status, the health effects and the derivation of the limit value. It also proposed prospects for the future development and revision of quality standards for total bacteria count in indoor air.

Mimicking Antioxidases and Hyaluronan Synthase: A Zwitterionic Nanozyme for Photothermal Therapy of Osteoarthritis

Restoring joint homeostasis is crucial for relieving osteoarthritis (OA). Current strategies are limited to unilateral efforts in joint lubrication, inhibition of inflammation, free radicals scavenging, and cartilage regeneration. Herein, by modifying molybdenum disulfide (MoS2 ) with Mg2+ -doped polydopamine and coating with polysulfobetaines, a dual-bionic photothermal nanozyme (MPMP) is constructed to mimic antioxidases/hyaluronan synthase for OA therapy. Photothermally enhanced lubrication lowers the coefficient of friction (0.028) in the early stage of OA treatment. The antioxidases-mimicking properties of MPMP nanozyme contribute to eliminating reactive oxygen and nitrogen species (ROS/RNS) (over 90% of scavenging ratio for H2 O2 /·OH/O· 2 - /DPPH/ABTS+ ) and supplying O2 . With NIR irradiation, the MPMP nanozyme triggers thermogenesis (upregulating HSP70 expression) and Mg2+ release, which promotes the chondrogenesis in inflammatory conditions by deactivating NF-κB/IL-17 signaling pathways and enhancing MAPK signaling pathway. Benefiting from HSP70 and Mg2+ , MPMP-NIR shows HAS-mimicking activity to increase the intracellular (twofold) and extracellular (3.12-fold) HA production. Therefore, MPMP-NIR demonstrates superior spatiotemporally therapeutic effect on OA in mice model, in terms of osteophytes (83.41% of reduction), OARSI scores (88.57% of reduction), and ACAN expression (2.70-fold of increment). Hence, insights into dual-bionic nanozymes can be a promising strategy for OA therapy or other inflammation-related diseases.

A hydrogel gripper enabling fine movement based on spatiotemporal mineralization

Fine tailoring of the subtle movements of a hydrogel actuator through simple methods has widespread application prospects in wearable electronics, bionic robots and biomedical engineering. However, to the best of our knowledge, this challenge is not yet completed. Inspired by the diffusion-reaction process in nature, a hydrogel gripper with the capability of fine movement was successfully prepared based on the spatiotemporal fabrication of the polypyrrole (PPY) pattern in a poly (N-isopropylacrylamide) (PNIPAM) hydrogel. The hydrogel was given gradient porous structures using a one-step UV irradiation method. Moreover, photothermal PPY patterns on the hydrogel were obtained through spatiotemporal mineralization of ferric hydroxide followed by the polymerization of pyrrole in a controllable manner. Taking advantage of the unique structures, the hydrogel gripper can not only achieve reversible grasping-releasing of substrates with the tuning of temperature (similar to that of hands), but also generate delicate movement under the irradiation of light (resembling that of finger joints). The strategy reported here is easily accessible and there is no need for sophisticated templates, therefore making it superior to other existing methods. We believe this work will provide references for the design and application of more advanced soft actuators.

Supramolecular Self-Healing Antifouling Coating for Dental Materials

In orthodontic treatment, orthodontic appliances are prone to bacterial infections, which pose a risk to oral health. Surface modification of orthodontic appliances has been explored to improve their antifouling properties and impart antibacterial capabilities, inhibiting initial bacterial adhesion and biofilm formation. However, coatings are susceptible to damage in the complex oral environment, leading to a loss of functionality. Here, we have prepared an antifouling self-healing coating based on supramolecular bonding by employing a simple spin coating method. The presence of the hydrophilic zwitterionic trimethylamine N-oxide (TMAO) and the hydrophobic antimicrobial moieties triclosan acrylate (TCSA) imparts to the polymers an amphiphilic structure and enhances the interaction with bacteria, resulting in excellent antimicrobial activity and surface antifouling properties. The multiple hydrogen bonds of ureido-pyrimidinone methacrylate (UPyMA) and ionic interactions contained in the polymers not only increased the adhesion of the coating to the material substrate (approximately 3 times) but also endowed the coating with the intrinsic self-healing ability to restore the antibiofouling properties at oral temperature and humidity. Finally, the polymer coating is biologically safe both in vitro and in vivo, showing no cytotoxic effects on cells and tissues. This research offers a promising avenue for improving the performance of orthodontic appliances and contributes to the maintenance and treatment of oral health.

[The incidence of artificial stone-related silicosis among interior decoration workers in different countries]

In this paper, 177 cases of artificial stone-related silicosis in interior decoration workers from Israel, Spain, USA, Italy and Australia were analyzed. Interior decoration workers were from small businesses (or workshops), engaged in kitchen and/or bathroom artificial stone countertops cutting, grinding, polishing and other reprocessing. In the working environment, the content of crystalline silica in artificial stone was more than 70%, and the concentration of silica dust exceeded the relevant standards. Most workplaces used dry cutting without ventilation and dust removal and other dust-proof measures, and most workers did not wear qualified respiratory protective equipment. Taking comprehensive measures such as wet operation, ventilation and dust removal, and individual protection can effectively prevent the occurrence of artificial stone-related silicosis.

[Association between cognitive impairment and main metals among oldest old aged 80 years and over in China]

Objective: To identify the main metals involved in cognitive impairment in the Chinese oldest old, and explore the association between these metal exposures and cognitive impairment. Methods: A cross-sectional study was conducted on 1 568 participants aged 80 years and older from Healthy Aging and Biomarkers Cohort Study (2017 to 2018). Fasting venous blood was collected to measure the levels of nine metals (selenium, lead, cadmium, arsenic, antimony, chromium, manganese, mercury, and nickel). The cognitive function of these participants was evaluated by using the Chinese version of the Mini-Mental State Examination (CMMSE). The random forest (RF) was applied to independently identify the main metals that affected cognitive impairment. The multivariate logistic regression model and restricted cubic splines (RCS) model were used to further verify the association of the main metals with cognitive impairment. Results: The age of 1 568 study subjects was (91.8±7.6) years old, including 912 females (58.2%) and 465 individuals (29.7%) with cognitive function impairment. Based on the RF model (the out-of-bag error rate was 22.9%), the importance ranking of variables was conducted and the feature screening of five times ten-fold cross-validation was carried out. It was found that selenium was the metal that affected cognitive function impairment, and the other eight metals were not included in the model. After adjusting for covariates, the multivariate logistic regression model showed that with every increase of 10 μg/L of blood selenium levels, the risk of cognitive impairment decreased (OR=0.921, 95%CI: 0.889-0.954). Compared with the lowest quartile(Q₁) of blood selenium, the ORs (95%CI) of Q₃ and Q₄ blood selenium were 0.452 (0.304-0.669) and 0.419 (0.281-0.622) respectively. The RCS showed a linear dose-response relationship between blood selenium and cognitive impairment (P_nonlinear>0.05). Conclusion: Blood selenium is negatively associated with cognitive impairment in the Chinese oldest old.

[Association of hs-CRP with frailty and its components among the elderly over 65 years old in 9 longevity areas of China]

Objective: To investigate the association of the levels of high sensitivity C-reactive protein (hs-CRP) with frailty and its components among the elderly over 65 years old in 9 longevity areas of China. Methods: Cross-sectional data from the Health Ageing and Biomarkers Cohort Study (HABCS, 2017-2018) were used and the elderly over 65 years old were included in this study. Through questionnaire interview and physical examination, the information including demographic characteristics, behavior, diet, daily activity, cognitive function, and health status was collected. The association between hs-CRP and frailty and its components in the participants was analyzed by multivariate logistic regression model and restrictive cubic spline. Results: A total of 2 453 participants were finally included, the age was (84.8±19.8) years old. The median hs-CRP level was 1.13 mg/L and the prevalence of frailty was 24.4%. Compared with the low-level group (hs-CRP<1.0 mg/L), the OR (95%CI) value of the high-level group (hs-CRP>3.0 mg/L) was 1.79 (1.35-2.36) mg/L. As for the components, the hs-CRP level was also positively associated with ADL disability, IADL disability, functional limitation and multimorbidity. After adjusting for confounding factors, compared with the low-level group, the OR (95%CI) values of the high-level group for the four components were 1.68 (1.25-2.27), 1.88 (1.42-2.50), 1.68 (1.31-2.14) and 1.39 (1.12-1.72), respectively. Conclusion: There is a positive association between the levels of hs-CRP and the risk of frailty among the elderly over 65 years old in 9 longevity areas of China. The higher hs-CRP level may increase the risk of frailty by elevating the risk of four physical functional disabilities, namely ADL disability, IADL disability, functional limitation and multimorbidity.

[Malaria control knowledge and behaviors and their influencing factors among residents in Banlao Township, Cangyuan County, Yunnan Province]

OBJECTIVE

To investigate the awareness of malaria-related knowledge, the use of mosquito nets and their influencing factors among residents in Banlao Township, Cangyuan County, Yunnan Province.

METHODS

In August 2020, 19 settlement sites in Banlao Township, Cangyuan County, Lincang City, Yunnan Province were selected as study areas, and permanent residents at ages of 10 years and older were enrolled for a questionnaire survey, including residents' demographics, family economic status, malaria control knowledge and use of mosquito nets. In addition, the factors affecting the use of mosquito nets in the night prior to the survey were identified using multivariate logistic regression analysis.

RESULTS

A total of 320 questionnaires were allocated, and all were recovered (a 100% recovery rate). There were 316 valid questionnaires, with an effective recovery rate of 98.75%. The 316 respondents included 152 men and 164 women and 250 Chinese respondents and 66 foreign respondents. The awareness of clinical syndromes of malaria was significantly higher among Chinese residents (71.60%) than among foreign residents (50.00%) (χ² = 11.03, P < 0.01), and the proportions of Chinese and foreign residents sleeping under mosquito nets were 46.00% and 69.70% on the night prior to the survey, respectively (χ² = 11.73, P < 0.01). Multivariate logistic regression analysis identified ethnicity group and type of residence as factors affecting the use of mosquito nets in the night prior to the survey.

CONCLUSIONS

The awareness of malaria control knowledge, the coverage and the use of mosquito nets were low among residents in Banlao Township, Cangyuan County, Yunnan Province. Targeted health education is recommended to improve the awareness of malaria control knowledge and self-protection ability. In addition, improving the allocation of long-lasting mosquito nets and health education pertaining to their uses and increasing the proportion of using mosquito nets correctly is needed to prevent re-establishment of imported malaria.

Supramolecular Photonic Hydrogel for High-Sensitivity Alkaline Phosphatase Detection via Synergistic Driving Force

Structurally-colored photonic hydrogels which are fabricated by introducing hydrogels into thin films or photonic crystal structures are promising candidates for biosensing. Generally, the design of photonic hydrogel biosensors is based on the sensor-analyte interactions induced charge variation within the hydrogel matrix, or chemically grafting binding sites onto the polymer chains, to achieve significant volume change and color variation of the photonic hydrogel. However, relatively low anti-interference capability or complicated synthesis hinder the facile and low-cost fabrication of high-performance photonic hydrogel biosensors. Here, a facilely prepared supramolecular photonic hydrogel biosensor is developed for high-sensitivity detection of alkaline phosphatase (ALP), which is an extensively considered clinical biomarker for a variety of diseases. Responding to ALP results in the broken supramolecular crosslinking and thus increased lattice distancing of the photonic hydrogel driven by synergistic repulsive force between nanoparticles embedded in photonic crystal structure and osmotic swelling pressure. The biosensor shows sensitivity of 7.3 nm spectral shift per mU mL^-1 ALP, with detection limit of 0.52 mU mL^-1 . High-accuracy colorimetric detection can be realized via a smartphone, promoting point-of-care sensing and timely diagnosis of related pathological conditions.

Prediction of knee pain improvement over two years for knee osteoarthritis using a dynamic nomogram based on MRI-derived radiomics: a proof-of-concept study

OBJECTIVES

To develop and validate a nomogram to detect improved knee pain in osteoarthritis (OA) by integrating magnetic resonance imaging (MRI) radiomics signature of subchondral bone and clinical characteristics.

METHODS

Participants were selected from the Vitamin D Effects on Osteoarthritis (VIDEO) study. The primary outcome was 20% improvement of knee pain score over 2 years in participants administrated either vitamin D or placebo. Radiomics features of subchondral bone and clinical characteristics from 216 participants were extracted and analyzed. The participants were randomly split into the training and validation cohorts at a ratio of 8:2. Least absolute shrinkage and selection operator (LASSO) regression was used to select features and generate radiomics signatures. The optimal radiomics signature and clinical indicators were fitted into a nomogram using multivariable logistic regression model.

RESULTS

The nomogram showed favorable discrimination performance [AUC_training, 0.79 (95% CI: 0.72-0.79), AUC_validation, 0.83 (95% CI: 0.70-0.96)] as well as a good calibration. Additional contributing value of fusion radiomics signature to the nomogram was statistically significant (NRI, 0.23; IDI, 0.14, P < 0.001 in training cohort and NRI, 0.29; IDI, 0.18, P < 0.05 in validating cohort). Decision curve analysis confirmed the clinical usefulness of nomogram.

CONCLUSION

The radiomics-based nomogram comprising the MR radiomics signature and clinical variables achieves a favorable predictive efficacy and accuracy in differentiating improvement in knee pain among OA patients. This proof-of-concept study provides a promising way to predict clinically meaningful outcomes.

Characterization of an ablative fractional CO2 laser-induced wound-healing model based on in vitro 3D reconstructed skin

OBJECTIVE

This study describes the development and characterization of a novel in vitro wound-healing model based on a full-thickness reconstructed skin by exposing the tissue to fractional ablative laser treatment.

METHOD

A 3D full-thickness skin model was fabricated and treated with fractional ablative CO₂ laser. Wound-healing process was characterized by HE staining, noninvasive OCT imaging, immunostaining, as well as transepidermal water loss measurement. Cytokines and proteins involved in the inflammatory and dermal remodeling process were studied by ELISA and protein array assays.

RESULTS

Fractional ablative CO₂ treatment induced a wound zone of 9 mm in diameter, containing 56 micro-wounds with 200 μm diameter and 500-700 μm in depth on reconstructed full-thickness skin model. HE staining revealed a typical wound morphology and healing process with migration of keratinocytes, formation and extrusion of necrotic tissue, and cell inclusion in dermis, which correlates with clinical observations. Based on OCT and TEWL measurements, the re-epithelialization took place over 2 days. Laser-triggered keratinocytes proliferation and differentiation were demonstrated by activated Ki67 and Filaggrin expression respectively. Injury-invoked cytokine ICAM-1 showed instant upregulation on Day 1. Decreased epidermis thickness and depression of IGFBP-2 protein level synergistically indicated the unavoidable thermal side effects from laser treatment. Downregulated DKK-1 protein level and upregulation of α-SMA together implicated the risk of potential fibrosis post-laser treatment.

CONCLUSION

This in vitro laser wounded reconstructed skin model captured the key events of wound-healing process, could be used to investigate the mechanisms of wound-healing triggered by a commonly used beauty procedure, and also provides a valuable tool for evaluating the efficacy of novel actives for the post-procedure application.

Recent advancements in wound management: Tailoring superwettable bio-interfaces

Skin tissue suffering from severe damages fail in self-regeneration. Proper wound dressings are highly demanded to protect the wound region and accelerate the healing process. Although large efforts have been devoted, there still exist disturbing dilemmas for traditional dressings. The exquisite design of bio-interface upon superwettable materials opens new avenues and addresses the problems perfectly. However, the advancements in this area have rarely been combed. In light of this, this minireview attempts to summarize recent strategies of superwettable bio-interfaces for wound care. Concentrating on the management of biofluids (blood and exudate), we described superwettable hemostatic bio-interfaces first, and then introduced the management of exudates. Finally, the perspective of this area was given. This minireview gives a comprehensive outline for readers and is believed to provide references for the design of superwettable materials in biomedical area.

Electrocatalytic NAD+ reduction via hydrogen atom-coupled electron transfer

Nicotinamide adenine dinucleotide cofactor (NAD(P)H) is regarded as an important energy carrier and charge transfer mediator. Enzyme-catalyzed NADPH production in natural photosynthesis proceeds via a hydride transfer mechanism. Selective and effective regeneration of NAD(P)H from its oxidized form by artificial catalysts remains challenging due to the formation of byproducts. Herein, electrocatalytic NADH regeneration and the reaction mechanism on metal and carbon electrodes are studied. We find that the selectivity of bioactive 1,4-NADH is relatively high on Cu, Fe, and Co electrodes without forming commonly reported NAD2 byproducts. In contrast, more NAD2 side product is formed with the carbon electrode. ADP-ribose is confirmed to be a side product caused by the fragmentation reaction of NAD+. Based on H/D isotope effects and electron paramagnetic resonance analysis, it is proposed that the formation of NADH on these metal electrodes proceeds via a hydrogen atom-coupled electron transfer (HadCET) mechanism, in contrast to the direct electron-transfer and NAD˙ radical pathway on carbon electrodes, which leads to more by-product, NAD2. This work sheds light on the mechanism of electrocatalytic NADH regeneration, which is different from biocatalysis.

[Direct intraoperative two-step distraction and reduction for basilar invagination with atlantoaxial dislocation]

Objective: To assess the clinical impact of direct two-step distraction reduction (TSDR) for basilar invagination (BI) with atlantoaxial dislocation (AAD). Methods: Retrospective analysis was conducted on the clinical data of patients who underwent TSDR and occipitocervical fusion in West China Hospital between October 2013 and March 2021. Depending on whether the preoperative decrease was greater than 50% on preoperative hyperextension X-rays, the patients were split into two groups. The neurological function [Japanese Orthopedic Association (JOA) score], atlantodens interval (ADI), the distance of odontoid process beyond McRae Line (ML) and Wackenheim Line (WL), cervicomedullary angle (CMA), O-C₂ angle (OC2A), and complications incidence were compared between two groups preoperatively and postoperatively. Results: There were 12 men and 23 women among the 35 patients with BI and AAD, and the age ranged from 28 to 71 years, with an mean age of (52.0±13.4) years. In the preoperative reduction ≥50% group, there were 4 males and 9 females with an average age of (54.0±13.8) years; in the preoperative reduction <50% group, there were 8 males and 14 females with a mean age of (50.9±13.4) years. All the patients were followed-up for a mean time of (23.3±13.4) months. There was no significant difference in age, gender, bleeding, length of hospital stay and follow-up time between the two groups (all P>0.05). The JOA score, ADI, WL, ML and CMA of 35 patients were significantly improved when compared with those before operation (all P<0.05). The reduction degree of ADI, ML and WL was more than 80% in 31 cases (88.57%), 30 cases (85.71%) and 31 cases (88.57%), respectively. There was no significant difference in postoperative ADI, ML and WL between the two groups (all P>0.05). All patients had no incision infection, no loosening or breakage of the internal fixators. Dysphagia occurred in 3 patients, non-fusion happened in 1 patient, but no instability in X-ray of cervical dynamic position was found, no loosening or displacement occurred in internal fixators, and partial spontaneous fusion occurred between atlantoaxial lateral mass joints. Conclusions: For BI with AAD without atlantoaxial bony connection or serious atlantoaxial facet joint inclination, TSDR could obtain satisfactory reduction degree. The reduction degree on preoperative hyperextension X-ray doesn't affect the degree of intraoperative reduction.

Evaluating the impact of metformin targets on the risk of osteoarthritis: a mendelian randomization study

OBJECTIVE

To provide some causal evidence concerning the effects of metformin on osteoarthritis (OA) using two metformin targets, namely AMP-activated protein kinase (AMPK) and growth differentiation factor 15 (GDF-15) as metformin proxies.

METHODS

This is a 2-sample Mendelian randomization design. We constructed 44 AMPK-related variants genetically predicted in HbA1c (%) as instruments for AMPK and five variants strongly predicted GDF-15 as instruments for GDF-15. Summary-level data for three OA phenotypes, including OA at any site, knee OA, and hip OA were obtained from the largest genome-wide meta-analysis across the UK Biobank and arcOGEN with 455,211 Europeans. Main analyses were conducted using the inverse-variance weighted method. Weighted median and MR-Egger were conducted as sensitivity analyses to assess the robustness of our results.

RESULTS

Genetically predicted AMPK were negatively associated with OA at any site (OR: 0.60; 95% CI: 0.43-0.83) and hip OA (OR: 0.42; 95% CI: 0.22-0.80), but with not knee OA (OR: 0.85; 95% CI: 0.49-1.50). Higher levels of genetically predicted GDF-15 reduced the risk of hip OA (OR: 0.95; 95% CI: 0.90-0.99), but not OA at any site (OR: 1.00; 95% CI: 0.98-1.02) and knee OA (OR: 1.02; 95% CI: 0.98-1.07).

CONCLUSION

This study indicates that AMPK and GDF-15 can be potential therapeutic targets for OA, especially for hip OA, and metformin would be repurposed for OA therapy which needs to be verified in randomized controlled trials.

Chloroplast-inspired Scaffold for Infected Bone Defect Therapy: Towards Stable Photothermal Properties and Self-Defensive Functionality

Bone implant-associated infections induced by bacteria frequently result in repair failure and threaten the health of patients. Although black phosphorus (BP) material with superior photothermal conversion ability is booming in the treatment of bone disease, the development of BP-based bone scaffolds with excellent photothermal stability and antibacterial properties simultaneously remains a challenge. In nature, chloroplasts cannot only convert light into chemical energy, but also hold a protective and defensive envelope membrane. Inspired by this, a self-defensive bone scaffold with stable photothermal property is developed for infected bone defect therapy. Similar to thylakoid and stroma lamella in chloroplasts, BP is integrated with chitosan and polycaprolactone fiber networks. The mussel-inspired polydopamine multifunctional "envelope membrane" wrapped above not only strengthens the photothermal stability of BP-based scaffolds, but also realizes the in situ anchoring of silver nanoparticles. Bacteria-triggered infection of femur defects in vivo can be commendably inhibited at the early stage via these chloroplast-inspired implants, which then effectively promotes endogenous repair of the defect area under mild hyperthermia induced by near-infrared irradiation. This chloroplast-inspired strategy shows outstanding performance for infected bone defect therapy and provides a reference for the functionality of other biomedical materials.

Effectiveness of vitamin D supplementation on knee osteoarthritis - A target trial emulation study using data from the Osteoarthritis Initiative cohort

OBJECTIVE

To assess the real-world effectiveness of vitamin D supplementation in patients with knee osteoarthritis (KOA) by replicating a randomized controlled trial (RCT) design in an observational study.

METHOD

This study emulated a target trial using data from the Osteoarthritis Initiative (OAI). Eligible participants were ≥45 years, had symptomatic KOA and did not take vitamin D supplements in the past 30 days. A participant can enter the trial more than once. Participants were included in vitamin D group if they took ≥1,000 IU/day for ≥4 days/week in the past 30 days at the first follow-up visit after baseline. The control group did not use vitamin D in the past 30 days. Optimal propensity score matching at 1:1 ratio was performed. The primary outcome was change in knee pain 2 years after baseline measured by the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC). Secondary outcomes included WOMAC physical function and quantitative joint space width (JSW). Standardized mean difference (SMD) was used to compare the findings with previous RCTs.

RESULTS

A total of 236 person-trials in the vitamin D group were pair-matched with a control. Compared to the control group, vitamin D supplementation did not reach significant changes in WOMAC pain (SMD = -0.04, 95%CI [-0.21, 0.13]), physical function and radiographic JSW over 2 years. The SMDs were consistent with the effect sizes reported in previous RCTs.

CONCLUSION

Target trial emulation in the OAI cohort demonstrated findings close to published RCTs. This supports the future use of target trial emulation in evaluating other systemic therapies for KOA.

Proteome Analysis of Temporomandibular Joint with Disc Displacement

Disc displacement without reduction is a common disorder of the temporomandibular joint, causing clinical symptoms and sometimes condylar degeneration. In some cases, bone regeneration is detected following disc-repositioning procedures. Until now, however, systems-wide knowledge of the protein levels for condylar outcome with disc position is still lacking. Here, we performed comprehensive expression profiling of synovial fluid from 109 patients with disc displacement without reduction using high-resolution data-independent acquisition mass spectrometry and characterized differences in 1,714 proteins. Based on magnetic resonance imaging, samples were divided into groups with versus without condylar absorption and subgroups with versus without new bone. For the proteomic analysis, 32 proteins in groups presented with statistical significance (>2-fold, P < 0.05). Pathways such as response to inorganic substances, blood coagulation, and estrogen signaling were significantly expressed in the group with bone absorption as compared with pathways such as regulation of body fluid levels, vesicle-mediated transport, and focal adhesion, which were enriched in the group without bone absorption. In subgroup analysis, 45 proteins of significant importance (>2-fold, P < 0.05) were associated with pathways including would healing, glycolysis and gluconeogenesis, and amino acid metabolism. Combined with clinical examination, molecules such as acetyl-CoA carboxylase beta (ACACB) and transforming growth factor beta 1 (TGFB1) were related to features such as visual analog scale and maximum interincisal opening (P < 0.05). In addition, 7 proteins were examined by Western blotting, including progesterone immunomodulatory binding factor 1 (PIBF1), histidine-rich glycoprotein (HRG), and protein kinase C and casein kinase substrate in neurons 2 (PACSIN2). In conclusion, this study provides the first proteome analysis of condylar absorption at disc displacement without reduction and postoperative new bone formation after disc reposition. Integrated with clinical data, this analysis provides an important insight into the proteomics of condylar modification at disc position.

[The influence of meteorological factors on SARS-CoV-2 transmission: evidence from laboratory and epidemiological studies]

SARS-CoV-2 has infected more than 600 million people worldwide and caused more than 6 million deaths. The emerging novel variants have made the epidemic rebound in many places. Meteorological factors can affect the epidemic spread by changing virus activity, transmission dynamic parameters and host susceptibility. This paper systematically analyzed the currently available laboratory and epidemiological studies on the association between the meteorological factors and COVID-19 incidence, in order to provide scientific evidence for future epidemic control and prevention, as well as developing early warning system.

Synovitis mediates the association between bone marrow lesions and knee pain in osteoarthritis: data from the Foundation for the National Institute of Health (FNIH) Osteoarthritis Biomarkers Consortium

OBJECTIVES

Although subchondral bone marrow lesions (BMLs) and synovitis have been well acknowledged as important sources of pain in knee osteoarthritis (KOA), it is unclear if synovitis plays the mediating role in the relationship between BMLs and knee pain.

METHODS

We analyzed 600 subjects with magnetic resonance imaging (MRI) in the Foundation for National Institutes of Health Osteoarthritis Biomarkers Consortium (FNIH) cohort at baseline and 24-month. BMLs and synovitis were measured according to the MRI Osteoarthritis Knee Score (MOAKS) scoring system. BMLs were scored in five subregions. A summary synovitis score of effusion and Hoffa-synovitis was calculated. Knee pain was evaluated using the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC). Linear regression models were applied to analyze the natural direct effect (NDE) of BMLs and synovitis with knee pain, respectively, and natural indirect effect (NIE) mediated by synovitis.

RESULTS

590 participants (58.8% females, with a mean age of 61.5) were included in the present analyses. For NDE, knee pain was cross-sectionally associated with medial femorotibial BMLs (β = 0.23, 95% CI: 0.09, 0.38) and synovitis (β = 0.40, 95% CI: 0.20, 0.60). Longitudinal associations retained significant [medial femorotibial BMLs (β = 0.37, 95% CI: 0.21, 0.53); synovitis (β = 0.72, 95% CI: 0.45, 0.99)]. In the NIE analyses, synovitis mediated the association between medial femorotibial BML and knee pain at baseline (β = 0.051, 95% CI: 0.01, 0.09) and over 24 months (β = 0.079, 95% CI: 0.023, 0.15), with the mediating proportion of 17.8% and 22.4%, respectively.

CONCLUSION

Synovitis partially mediates the association between medial femorotibial BMLs and knee pain.

Chitosan-Based Scaffolds for Facilitated Endogenous Bone Re-Generation

Facilitated endogenous tissue engineering, as a facile and effective strategy, is emerging for use in bone tissue regeneration. However, the development of bioactive scaffolds with excellent osteo-inductivity to recruit endogenous stem cells homing and differentiation towards lesion areas remains an urgent problem. Chitosan (CS), with versatile qualities including good biocompatibility, biodegradability, and tunable physicochemical and biological properties is undergoing vigorously development in the field of bone repair. Based on this, the review focus on recent advances in chitosan-based scaffolds for facilitated endogenous bone regeneration. Initially, we introduced and compared the facilitated endogenous tissue engineering with traditional tissue engineering. Subsequently, the various CS-based bone repair scaffolds and their fabrication methods were briefly explored. Furthermore, the functional design of CS-based scaffolds in bone endogenous regeneration including biomolecular loading, inorganic nanomaterials hybridization, and physical stimulation was highlighted and discussed. Finally, the major challenges and further research directions of CS-based scaffolds were also elaborated. We hope that this review will provide valuable reference for further bone repair research in the future.

Charge Separation by Creating Band Bending in Metal-Organic Frameworks for Improved Photocatalytic Hydrogen Evolution

Metal-organic frameworks (MOFs) have been intensively studied as a class of semiconductor-like materials in photocatalysis. However, band bending, which plays a crucial role in semiconductor photocatalysis, has not yet been demonstrated in MOF photocatalysts. Herein, a representative MOF, MIL-125-NH₂ , is integrated with the metal oxides (MoO₃ and V₂ O₅ ) that feature appropriate work functions and energy levels to afford the corresponding MOF composites. Surface photovoltage results demonstrate band bending in the MOF composites, which gives rise to the built-in electric field of MIL-125-NH₂ , boosting the charge separation. As a result, the MOF composites present 56 and 42 times higher activities, respectively, compared to the pristine MOF for photocatalytic H₂ production. Upon depositing Pt onto the MOF, ∼6 times higher activity is achieved. This work illustrates band bending of MOFs for the first time, supporting their semiconductor-like nature, which would greatly promote MOF photocatalysis.

Invisible assassin coated on dental appliances for on-demand capturing and killing of cariogenic bacteria

The accumulation of microbes on long-wear artificial dental materials creates a great risk for oral diseases and causes deterioration of material properties. Therefore, smart antibacterial materials capable of resisting the colonization of microorganisms and simultaneously eliminating pathogenic bacteria as needed show outstanding superiority for the recovery of dental health, which are scarcely reported until now. Here, we present a responsive hydrogel coating as invisible assassin on clear overlay appliances target for dental caries. Taking advantage of pH-responsive carboxybetaine methacrylate-dimethylaminoethyl methacrylate copolymer P(CBMA-co-DMAEMA) and antibacterial peptides, the surface potential of hydrogel shifts positively, accompanied with the release of antibacterial peptides when pH gets lower. The hybrid hydrogel layer hence exerts antifouling property and resists bacterial adhesion in normal physiological, while captures and kills cariogenic bacteria in acidic condition. This biocompatible, transparent and stable hydrogel coating has little influence for the aesthetics and mechanical properties of bulk materials. The strategy developed here can provide reference for the design of biomedical devices in other areas.

Optimize the irrigation and fertilizer schedules by combining DSSAT and genetic algorithm

As one of the main food crops in the world, the yield of maize directly affects the food security of the world. The optimization of irrigation and fertilizer schedules is also one of the hot issues in the world. However, the traditional optimization methods are mainly based on field experiment or crop model. The research on combining crop model with optimization algorithm to optimize irrigation and fertilizer schedule is rare. In this paper, the genetic algorithm (GA) and DSSAT crop model were combined to provide theoretical basis for the optimization of irrigation and fertilizer schedules of maize in China. On the basis of field experimental data in previous references, the model was calibrated and verified, and get a well simulation result with RMSE ranged from 0.262 to 0.580 Mg/ha. After that, GA and DSSAT were run to obtain the optimized irrigation and fertilizer schedules. Compared with the results of previous references, the new optimization schedules can improve the yield (1.9 ~ 2.6%) and economic benefits (7.3 ~ 8.9%). It is proved that this method has a good optimization effect, and the method also has a wide range of research prospects.

Coupling effect between hole storage and interfacial charge transfer over ultrathin CoPi-modified hematite photoanodes

Understanding the functionality of the modification layer in regulating the charge transfer process at the semiconductor/electrolyte interface is of great significance to the rational design of photoelectrocatalytic water oxidation systems. Herein, by systematically investigating and comparing the charge transfer kinetics behaviors over ferrihydrite (Fh)- and cobalt phosphate (CoPi)-modified hematite (Fe₂O₃) photoanodes, we unveiled the essential relation between photocurrent enhancement and the charge transfer process. With the hole-storage material Fh as a reference, it was found that CoPi demonstrates high hole-storage capacity at a low bias region (<1.0 V vs. RHE) due to the effective release of Fermi level pinning. Afterwards, the stored holes would be timely injected into the electrolyte for water oxidation, caused by the enhanced charge separation in the presence of CoPi. In contrast, the decoration of Fh can only slightly passivate the surface states and promote hole injection in the high potential region. Subsequently, superior hole-storage capacity in the low-potential region is recognized as a crucial factor for photocurrent enhancement. These combined results provide new insights into the understanding of interfacial charge transfer kinetics.

Comparison of the Utility of High-Resolution CT-DWI and T2WI-DWI Fusion Images for the Localization of Cholesteatoma

BACKGROUND AND PURPOSE

Cholesteatoma is an aggressive disease that may lead to hearing impairment. This study aimed to compare the utility of high-resolution CT and TSE-DWI fusion images with that of T2WI and TSE-DWI fusion images in the localization of middle ear cholesteatoma.

MATERIALS AND METHODS

Seventy-one patients with middle ear cholesteatoma were retrospectively recruited. High-resolution CT, T2WI with fat suppression, and TSE-DWI scans were obtained, and image fusion was performed using a 3D reconstruction postprocessing workstation to form CT-DWI and T2WI-DWI fusion images. The quality of the 2 fused images was subjectively evaluated using a 5-point Likert scale with the horizontal semicircular canal transverse position as the reference. Receiver operating characteristic analysis was performed, and the diagnostic efficacies of CT-DWI and T2WI-DWI fusion images in localizing middle ear cholesteatoma were calculated.

RESULTS

The overall quality of T2WI-DWI fusion images was slightly higher than that of CT-DWI fusion images (P < .001), and the semicircular canal was slightly less clear on T2WI-DWI than on CT-DWI (P < .001). No statistical difference was found in the diagnostic confidence between them. In the localization of middle ear cholesteatoma, the accuracy, sensitivity, and specificity of T2WI-DWI fusion images and CT-DWI fusion images were equivalent for involvement of the attic, tympanic cavity, mastoid antrum, and mastoid process, with no statistically significant differences.

CONCLUSIONS

T2WI-DWI fusion images could replace CT-DWI in the preoperative selection of surgical options for middle ear cholesteatoma.

AB0978 Effect of atorvastatin on skeletal muscles of patients with knee osteoarthritis: post-hoc analysis of a randomised controlled trial

Background

Statins are often discontinued due to muscle-related side effects. The effect of statin on skeletal muscles in populations with osteoarthritis is unknown.

Objectives

This study aims to examine the effect of atorvastatin on skeletal muscle biochemistry, strength, size and symptoms in patients with symptomatic knee osteoarthritis.

Methods

This is a post-hoc analysis of a multicentre randomised, double-blind, placebo-controlled trial over 2 years in which participants with knee osteoarthritis who met the American College of Rheumatology clinical criteria received atorvastatin 40mg daily (n=151) or placebo (n=153). Outcomes included levels of creatinine kinase (CK), aspartate transaminases (AST) and alanine transaminases (ALT) at baseline, 4 weeks, 6, 12 and 24 months; muscle strength measured by dynamometry at baseline, 12 and 24 months; vastus medialis cross-sectional area (CSA) on magnetic resonance imaging at baseline and 24 months; and self-reported myalgia during the trial.

Results

304 participants [mean age 55.7 (SD 7.6) years, 55.6% female] were randomised. There were no significant differences in CK and AST levels between atorvastatin and placebo groups at 4 weeks (CK median 107 vs 110, p=0.76; AST 22 vs 21, p=0.14), 6 (CK 109 vs 101.5, p=0.37; AST 21 vs 20, p=0.45), 12 (CK 103 vs 103, p=0.93; AST 22 vs 21, p=0.99), and 24 (CK 103 vs 93.5, p=0.17; AST 22 vs 21, p=0.34) months. The atorvastatin group had higher ALT levels than the placebo group at 4 weeks [26 vs 21, p=0.0004] and 6 months [25 vs 22, p=0.007] but no between-group differences at 12 [24 vs 21, p=0.08] and 24 [24 vs 21, p=0.053] months. Muscle strength significantly increased in the atorvastatin group but not the placebo group over 24 months with no between-group differences [mean 8.5 (95% CI 2.6,14.4) vs 5.6 (-0.3,11.5), p=0.50]. Change in vastus medialis CSA over 24 months showed between-group differences favouring the atorvastatin group [+0.12 (-0.09,0.34) vs -0.24 (-0.48,0.01), p=0.03] but of uncertain clinical significance. There was a trend for more myalgia in the atorvastatin group over 2 years (8/151 vs 2/153, p=0.06), mostly occurring within 6 months (7/151 vs 1/153, p=0.04). Of the 10 participants with myalgia, there was no relationship between the incidence of myalgia and CK levels.

Conclusion

In those with symptomatic knee osteoarthritis, despite a trend for more myalgia, there was no clear evidence of an adverse effect of atorvastatin on skeletal muscles, including those most relevant to knee joint health.

Disclosure of Interests

Yuan Lim: None declared, Flavia Cicuttini: None declared, Anita Wluka: None declared, Graeme Jones Speakers bureau: GJ received honoraria for talks from BMS, Roche, AbbVie, Amgen, Lilly, Novartis, and Janssen, Grant/research support from: GJ received grant for a clinical trial from Covance, Catherine Hill: None declared, Andrew Forbes: None declared, Andrew Tonkin Speakers bureau: AT received honoraria for lectures from Pfizer; honoraria for lectures and advisory board participation from Amgen, Consultant of: AT received honoraria for lectures and advisory board participation from Amgen, honoraria for data and safety monitoring board participation from Merck, and honoraria for data and safety monitoring board participation from Novartis, Sofia Berezovskaya: None declared, Lynn Tan: None declared, Changhai Ding: None declared, Yuanyuan Wang: None declared

POS0412 ENHANCING SURVIVAL AND THERAPEUTIC EFFECT OF MESENCHYMAL STEM CELLS IN RAT MODEL OF RHEUMATOID ARTHRITIS VIA NANOMODIFICATION

Background

Mesenchymal stem cells (MSCs) have immunomodulatory, multilineage differentiation, and inflammatory/injury site-homing properties. These unique therapeutic features enable MSCs to be used in the treatment of rheumatoid arthritis (RA). However, MSCs therapy is still facing multiple obstacles in RA. First, MSCs are sensitive to inflammatory microenvironment (e.g., high level of reactive oxygen species [ROS]) and hence lose viability and immune regulatory effect when exposed in the inflamed joint. Second, uncontrolled differentiation of MSCs leads to the failure of cartilage repair.

Objectives

The aim of this study was to develop nanoparticle (NP)-modified MSCs that can maintain their biofunctions under the RA-associated oxidized stress and chondrogenically differentiate to repair cartilage.

Methods

Copper sulfide@manganese dioxide (CuS@MnO2) NPs were sythesized, then modified with an MSC-targeting peptide (VTAMEPGQ, termed VQ) and loaded with metformin (MET) to produce VQ-CuS@MnO2/MET (termed VCMM) NPs. After cellular uptake, the NP-modified VCMM-MSCs were obtained. The basic functions, chondrogenesis, anti-inflammatory effect and cell viability under oxidized stress of VCMM-MSCs were studied in vitro. Further, VCMM-MSCs were intravenously (i.v.) injected into rat models of collegan-induced arthritis (CIA) and adjuvant-induced arthritis (AIA) to evaluate their survival and therapeutic effect in vivo.

Results

The NP-modified VCMM-MSCs exhibited stronger capabilities of cell migration and chondrogenesis relative to bare MSCs. VCMM-MSCs were also better than bare MSCs in terms of anti-inflammation towards lipopolysaccharide-induced M1 macrophages (RAW264.7). Moreover, VCMM-MSCs could survive under the RA-associated oxidized stress through catalyzing intracelluar ROS into oxygen by the superoxide dismutase (SOD)- and catalase (CAT)-like activities of the NPs, whereas approximately half of bare MSCs were dead. After i.v. injection into CIA and AIA rats, VCMM-MSCs lived longer and accumulated more abundant in the inflamed joints relative to bare MSCs (determined by in vivo fluorescence imaging). They promoted the repolarization of macrophages from M1 to M2 type in synovium, thereby inhibiting synovial inflammation in vivo. Further, VCMM-MSCs enhanced the sythesis of glycosaminoglycan and type II collegan in cartilage and thus promoted joint reapir.

Conclusion

The NP-modified VCMM-MSCs alleviated arthritis syndrome of both CIA and AIA models through reducing synovial hyperplasia and cartilage destruction. Nanomodification of MSCs may provide a new strategy to improve stem cell therapy in RA and other inflammatory diseases.

Acknowledgements

This study was supported by National Natural Science Foundation of China (81902198).

Disclosure of Interests

None declared.

POS0178 ASSOCIATION BETWEEN KNEE MR IMAGING MARKERS AND KNEE SYMPTOMS OVER 7 YEARS IN YOUNG ADULTS

Background

Knee magnetic resonance imaging (MRI)-based morphological markers (quantitative biomarkers) and structural abnormalities (semi-quantitative biomarkers) are known to be associated with the progression of knee osteoarthritis (OA). However, there is conflicting evidence on the association between knee MRI-based morphological markers and knee symptoms. Besides, there is a lack of evidence on the clinical significance of MR imaging markers in the general population-based young adults. Hence, our aim was to investigate the associations between MR imaging biomarkers and knee symptoms in middle-aged adults followed over seven years.

Objectives

To describe the associations of cartilage volume, cartilage thickness, subchondral bone area, cartilage defects, and bone marrow lesions (BML) with knee symptoms in young adults followed up over 6-9 years.

Methods

Knee symptoms (pain, stiffness, and dysfunction) were assessed using the Western Ontario and McMaster University Osteoarthritis Index (WOMAC) scale during Childhood Determinants of Adult Health (CDAH)-knee study at baseline (year: 2008-10, age: 30–40 years) and 6-9 year follow-up (CDAH-3; year: 2014–2019, age: 36–49 years). Knee MRI scans were obtained at baseline and were assessed quantitatively for morphological markers such as cartilage volume, cartilage thickness, subchondral bone area using semi-automated segmentation (Chondrometrics, Germany). Cartilage defects and BMLs were assessed using semi-quantitative scoring systems. Univariable and multivariable (adjusted for age, sex, and body mass index (BMI)) zero-inflated Poisson (ZIP) regression model with random effects were used to describe the cross-sectional and longitudinal associations.

Results

The prevalence of knee pain at baseline (mean age (SD): 34 (2.7); female 49%) was 34% that increased to 50% over 6-9 year follow-up (mean age (SD): 43 (3.2)). Cross sectionally, there was a weak but statistically significant negative association between medial femorotibial compartment (MFTC) [Ratio of Mean (RoM)= 0.99971084; 95% CI: (0.9995525, 0.99986921; p<0.001], lateral femorotibial compartment (LFTC) [RoM=0.99982602; 95% CI: 0.99969915, 0.9999529; p=0.007], and patellar cartilage volume [RoM=0.99981722; 95% CI: 0.99965326, 0.9999811; p=0.029] with knee symptoms.

Similarly, there was a negative association between patellar cartilage volume (RoM=0.99975523; 95% CI: 0.99961427, 0.99989621; p=0.014), MFTC cartilage thickness (RoM= 0.72090775; 95% CI: 0.59481806, 0.87372596; p=0.001) and knee symptoms assessed after seven years.

The total bone area was consistently and negatively associated with knee symptoms at baseline [RoM= 0.9210485; 95%CI: 0.8939677, 0.9489496; p<0.001] and over seven years (RoM=0.9588811; 95% CI: 0.9313379, 0.9872388; p=0.005). Presence of any cartilage defect or BML was associated with higher knee symptoms at baseline and after seven years.

Conclusion

In the middle-aged adult population, BML and cartilage defects were positively associated with knee symptoms, whereas cartilage volume and thickness at MFTC and total bone area were weakly and negatively associated with knee symptoms. These results suggest that the quantitative and semi-quantitative MR imaging biomarkers can be explored as a marker of the clinical progression of OA in a young adult population.

Disclosure of Interests

Benny Antony: None declared, Alison Venn: None declared, Leigh Blizzard: None declared, Lyn March: None declared, Flavia Cicuttini: None declared, Felix Eckstein Shareholder of: Shareholder of Chondrometrics, image processing company, Graeme Jones: None declared, Changhai Ding: None declared, Ambrish Singh: None declared

Association between osteoarthritis-related serum biochemical markers over 11 years and knee MRI-based imaging biomarkers in middle-aged adults

OBJECTIVE

To describe the associations between osteoarthritis (OA)-related biochemical markers (COMP, MMP-3, HA) and MRI-based imaging biomarkers in middle-aged adults over 10-13 years.

METHODS

Blood serum samples collected during the Childhood Determinants of Adult Health (CDAH)-1 study (year:2004-06; n = 156) and 10-13 year follow-up at CDAH-3 (n = 167) were analysed for COMP, MMP-3, and HA using non-isotopic ELISA. Knee MRI scans obtained during the CDAH-knee study (year:2008-10; n = 313) were assessed for cartilage volume and thickness, subchondral bone area, cartilage defects, and BML.

RESULTS

In a multivariable linear regression model describing the association of baseline biochemical markers with MRI-markers (assessed after 4-years), we found a significant negative association of standardised COMP with medial femorotibial compartment cartilage thickness (β:-0.070; 95%CI:-0.138,-0.001), and standardised MMP-3 with patellar cartilage volume (β:-141.548; 95%CI:-254.917,-28.179) and total bone area (β:-0.729; 95%CI:-1.340,-0.118). In multivariable Tobit regression model, there was a significant association of MRI-markers with biochemical markers (assessed after 6-9 years); a significant negative association of patellar cartilage volume (β:-0.001; 95%CI:-0.002,-0.00004), and total bone area (β:-0.158; 95%CI-0.307,-0.010) with MMP-3, and total cartilage volume (β:-0.001; 95%CI:-0.001,-0.0001) and total bone area (β:-0.373; 95%CI:-0.636,-0.111) with COMP. No significant associations were observed between MRI-based imaging biomarkers and HA.

CONCLUSION

COMP and MMP-3 levels were negatively associated with knee cartilage thickness and volume assessed 4-years later, respectively. Knee cartilage volume and bone area were negatively associated with COMP and MMP-3 levels assessed 6-9 years later. These results suggest that OA-related biochemical markers and MRI-markers are interrelated in early OA.

Understanding the factors governing the water oxidation reaction pathway of mononuclear and binuclear cobalt phthalocyanine catalysts

The rational design of efficient catalysts for electrochemical water oxidation highly depends on the understanding of reaction pathways, which still remains a challenge. Herein, mononuclear and binuclear cobalt phthalocyanine (mono-CoPc and bi-CoPc) with a well-defined molecular structure are selected as model electrocatalysts to study the water oxidation mechanism. We found that bi-CoPc on a carbon support (bi-CoPc/carbon) shows an overpotential of 357 mV at 10 mA cm⁻², much lower than that of mono-CoPc/carbon (>450 mV). Kinetic analysis reveals that the rate-determining step (RDS) of the oxygen evolution reaction (OER) over both electrocatalysts is a nucleophilic attack process involving a hydroxy anion (OH⁻). However, the substrate nucleophilically attacked by OH⁻ for bi-CoPc is the phthalocyanine cation-radical species (Co^II–Pc–Pc˙⁺–Co^II–OH) that is formed from the oxidation of the phthalocyanine ring, while cobalt oxidized species (Pc–Co^III–OH) is involved in mono-CoPc as evidenced by the operando UV-vis spectroelectrochemistry technique. DFT calculations show that the reaction barrier for the nucleophilic attack of OH⁻ on Co^II–Pc–Pc˙⁺–Co^II–OH is 1.67 eV, lower than that of mono-CoPc with Pc–Co^III–OH nucleophilically attacked by OH⁻ (1.78 eV). The good agreement between the experimental and theoretical results suggests that bi-CoPc can effectively stabilize the accumulated oxidative charges in the phthalocyanine ring, and is thus bestowed with a higher OER performance.

bi-CoPc can stabilize accumulated oxidative charges in phthalocyanine ring, which leads to the OER proceeding through a nucleophilic attack of OH^- on the phthalocyanine cation-radical species that is formed from the oxidation of phthalocyanine ring.