RPL35 downregulated by mechanical overloading promotes chondrocyte senescence and osteoarthritis development via Hedgehog-Gli1 signaling.

Objectives: To investigate the potential role of Ribosomal protein L35 (RPL35) in regulating chondrocyte catabolic metabolism and to examine whether osteoarthritis (OA) progression can be delayed by overexpressing RPL35 in a mouse compression loading model. Methods: RNA sequencing analysis was performed on chondrocytes treated with or without 20 % elongation strain loading for 24 h. Experimental OA in mice was induced by destabilization of the medial meniscus and compression loading. Mice were randomly assigned to a sham group, an intra-articular adenovirus-mediated overexpression of the negative group, and an intra-articular adenovirus-mediated overexpression of the RPL35 operated group. The Osteoarthritis Research Society International score was used to evaluate cartilage degeneration. Immunostaining and western blot analyses were conducted to detect relative protein levels. Primary mouse chondrocytes were treated with 20 % elongation strain loading for 24 h to investigate the role of RPL35 in modulating chondrocyte catabolic metabolism and regulating cellular senescence in chondrocytes. Results: The protein expression of RPL35 in mouse chondrocytes was significantly reduced when excessive mechanical loading was applied, while elevated protein levels of RPL35 protected articular chondrocytes from degeneration. In addition, the RPL35 knockdown alone induced chondrocyte senescence, decreased the expression of anabolic markers, and increased the expression of catabolic markers in vitro in part through the hedgehog (Hh) pathway. Conclusions: These findings demonstrated a functional pathway important for OA development and identified intra-articular injection of RPL35 as a potential therapy for OA prevention and treatment. The translational potential of this article: It is necessary to develop new targeted drugs for OA due to the limitations of conventional pharmacotherapy. Our study explores and demonstrates the protective effect of RPL35 against excessive mechanical stress in OA models in vivo and in vitro in animals. These findings might provide novel insights into OA pathogenesis and show its translational potential for OA therapy.

Corrigendum: A rapid VEGF-gene-sequence photoluminescence detector for osteoarthritis.

[This corrects the article DOI: 10.3389/fbioe.2024.1338901.].

A rapid VEGF-gene-sequence photoluminescence detector for osteoarthritis.

Osteoarthritis (OA) has become a serious problem to the human society for years due to its high economic burden, disability, pain, and severe impact on the patient's lifestyle. The importance of current clinical imaging modalities in the assessment of the onset and progression of OA is well recognized by clinicians, but these modalities can only detect OA in the II stage with significant structural deterioration and clinical symptoms. Blood vessel formation induced by vascular endothelial growth factor (VEGF) occurs in the early stage and throughout the entire course of OA, enables VEGF relating gene sequence to act as a biomarker in the field of early diagnosis and monitoring of the disease. Here in, a facile rapid detection of VEGF relating ssDNA sequence was developed, in which manganese-based zeolitic imidazolate framework nanoparticles (Mn-ZIF-NPs) were synthesized by a simple coprecipitation strategy, followed by the introduction and surficial absorption of probe ssDNAs and the CRISPR/Cas12a system components. Furthermore, fluorescence experiments demonstrated that the biosensor displayed a low detection limit of 2.49 nM, a good linear response to the target ssDNA ranging from 10 nM to 500 nM, and the ability of distinguishing single nucleotide polymorphism. This finding opens a new window for the feasible and rapid detection of ssDNA molecules for the early diagnose of OA.

Galectin from Trichinella spiralis alleviates DSS-induced colitis in mice by regulating the intestinal microbiota.

According to numerous reports, Trichinella spiralis (T. spiralis) and its antigens can reduce intestinal inflammation by modulating regulatory immunological responses in the host to maintain immune homeostasis. Galectin has been identified as a protein that is produced by T. spiralis, and its characterization revealed this protein has possible immune regulatory activity. However, whether recombinant T. spiralis galectin (rTs-gal) can cure dextran sulfate sodium (DSS)-induced colitis remains unknown. Here, the ability of rTs-gal to ameliorate experimental colitis in mice with inflammatory bowel disease (IBD) as well as the potential underlying mechanism were investigated. The disease activity index (DAI), colon shortening, inflammatory cell infiltration, and histological damage were used as indicators to monitor clinical symptoms of colitis. The results revealed that the administration of rTs-gal ameliorated these symptoms. According to Western blotting and ELISA results, rTs-gal may suppress the excessive inflammatory response-mediated induction of TLR4, MyD88, and NF-κB expression in the colon. Mice with colitis exhibit disruptions in the gut flora, including an increase in gram-negative bacteria, which in turn can result in increased lipopolysaccharide (LPS) production. However, injection of rTs-gal may inhibit changes in the gut microbiota, for example, by reducing the prevalence of Helicobacter and Bacteroides, which produce LPS. The findings of the present study revealed that rTs-gal may inhibit signalling pathways that involve enteric bacteria-derived LPS, TLR4, and NF-κB in mice with DSS-induced colitis and attenuate DSS-induced colitis in animals by modulating the gut microbiota. These findings shed additional light on the immunological processes underlying the beneficial effects of helminth-derived proteins in medicine.

Global, but not chondrocyte-specific, MT1-MMP deficiency in adult mice causes inflammatory arthritis.

Membrane-type I metalloproteinase (MT1-MMP/MMP14) plays a key role in various pathophysiological processes, indicating an unaddressed need for a targeted therapeutic approach. However, mice genetically deficient in Mmp14 show severe defects in development and growth. To investigate the possibility of MT1-MMP inhibition as a safe treatment in adults, we generated global Mmp14 tamoxifen-induced conditional knockout (Mmp14kd) mice and found that MT1-MMP deficiency in adult mice resulted in severe inflammatory arthritis. Mmp14kd mice started to show noticeably swollen joints two weeks after tamoxifen administration, which progressed rapidly. Mmp14kd mice reached a humane endpoint 6 to 8 weeks after tamoxifen administration due to severe arthritis. Plasma TNF-α levels were also significantly increased in Mmp14kd mice. Detailed analysis revealed chondrocyte hypertrophy, synovial fibrosis, and subchondral bone remodeling in the joints of Mmp14kd mice. However, global conditional knockout of MT1-MMP in adult mice did not affect body weight, blood glucose, or plasma cholesterol and triglyceride levels. Furthermore, we observed substantial expression of MT1-MMP in the articular cartilage of patients with osteoarthritis. We then developed chondrocyte-specific Mmp14 tamoxifen-induced conditional knockout (Mmp14chkd) mice. Chondrocyte MT1-MMP deficiency in adult mice also caused apparent chondrocyte hypertrophy. However, Mmp14chkd mice did not exhibit synovial hyperplasia or noticeable arthritis, suggesting that chondrocyte MT1-MMP is not solely responsible for the onset of severe arthritis observed in Mmp14kd mice. Our findings also suggest that highly cell-type specific inhibition of MT1-MMP is required for its potential therapeutic use.

Investigation on the Influence of Fiber Bundle Undulating Architecture on Tensile Behavior of Filament Wound Composite Laminates.

In filament wound composites, fiber bundles cross each other and form an undulating architecture, which may significantly affect the mechanical behavior of composites. In this study, the tensile mechanical behavior of filament wound laminates was studied experimentally and numerically, and the influences of the bundle thickness and winding angle on the mechanical behavior of the filament wound plates were also explored. In the experiments, tensile tests were carried out on filament wound plates and laminated plates. It was found that, compared to laminated plates, filament wound plates had lower stiffness, greater failure displacement, similar failure loads, and more obvious strain concentration areas. In numerical analysis, mesoscale finite element models, which take into account the fiber bundles' undulating morphology, were created. The numerical predictions correlated well with the experimental ones. Further numerical studies have shown that the stiffness reduction coefficient of filament wound plates with a winding angle of ±55° decreased from 0.78 to 0.74 as the bundle thickness increased from 0.4 mm to 0.8 mm. The stiffness reduction coefficients of filament wound plates with wound angles of ±15°, ±25°, and ±45° were 0.86, 0.83, and 0.8, respectively.

Bacterial cellulose production by a strain of Komagataeibacter rhaeticus isolated from residual loquat.

In this study, loquat extract was selected as a promising substrate for bacterial cellulose (BC) production. A new BC-producing bacterial strain was isolated from residual loquat and identified as Komagataeibacter rhaeticus. BC production with different carbon sources and with loquat extract was investigated. Among all tested carbon sources, glucose was demonstrated to be the best substrate for BC production by K. rhaeticus, with up to 7.89 g/L dry BC obtained under the optimal initial pH (5.5) and temperature (28 °C) with 10 days of fermentation. The total sugar and individual sugars were investigated in different loquat extracts, in which fructose, glucose, and sucrose were the three main sugars. When loquat extract was prepared with a solid‒liquid (S-L) ratio of 2:1, the concentrations of glucose, fructose, and sucrose were 7.91 g/L, 9.31 g/L, and 2.84 g/L, respectively. The BC production obtained from loquat extract was higher than that of other carbon sources except glucose, and 6.69 g/L dry BC was obtained from loquat extract with an S-L ratio of 2:1. After BC production, all sugars substantially decreased, with the utilization of glucose, fructose, and sucrose reaching 93.9%, 87.9%, and 100%, respectively. These results suggested that the different sugars in loquat extract were all carbon sources participating in BC production by K. rhaeticus. Structural and physicochemical properties were investigated by SEM, TGA, XRD, and FT-IR spectroscopy. The results showed that the structural, chemical group, and water holding capacity of BC obtained from loquat extract were similar to those of BC obtained from glucose, but the crystallinity and thermal stability of BC were higher than those of BC from mannose and lactose but lower than those of BC from glucose and fructose. KEY POINTS: • A new BC-producing strain was isolated and identified as Komagataeibacter rhaeticus. • Loquat extract is an alternative substrate for BC production. • The BC obtained from loquat extract owns advanced physicochemical properties.

Higher Pelvic Incidence Was Associated with a Higher Risk of Sagittal Malposition of Femoral Component and Poor Outcomes of Primary Total Knee Arthroplasty: A Retrospective Cohort Analysis.

Spine-pelvis-lower extremity sagittal alignment is regarded as a global sagittal balance. Currently, there are few studies evaluating the pelvic and femoral sagittal alignment during total knee arthroplasty (TKA). This retrospective study aims to elucidate how pelvic and femoral sagittal alignment affect clinical outcomes of primary TKA for osteoarthritis (OA) and determine the proper range of femoral sagittal alignment. Patient-reported outcome measures (PROMs), including the Knee Society Score (KSS), Western Ontario and McMaster Universities (WOMAC), and patient satisfaction scores, and clinician-reported outcomes (CROs), including range of motion (ROM) and pelvic and femoral sagittal parameters, of 67 cases were evaluated (89 knees) before and 1 year after TKA. The angle between the distal femur anterior cortex line and flange of the femoral component (FC) was defined as the α angle. Correlations between the α angle and PROM and CRO were investigated using multivariate and secondary regression analyses. Patients were further divided into four cohorts (A, B, C, and D) according to the α angle, and comparisons of their postoperative PROM and ROM scores were performed. Postoperative PROM and ROM scores improved significantly compared with the preoperative scores (p < 0.01). Only the α angle was significantly associated with postoperative knee extension among all PROM and CRO indexes (p = 0.001). Secondary regression demonstrated a convex upward function, and the scores were the highest at α angles of 0.57, 0.96, and -1.42 degrees for postoperative KSS, satisfaction, and range of knee extension, respectively (p < 0.01). However, the concave upward degree was the lowest at an α angle of 0.33 degrees for pelvic incidence (p < 0.001). Bonferroni's paired comparisons indicated that postoperative KSS and satisfaction of the cohort B (0 degrees ≤ α angle ≤ 3 degrees) were better than those of other cohorts (p < 0.0125). The results indicate that surgeons should pay more attention to the sagittal alignment of FC in patients with increased pelvic incidence, the distal femoral anterior cortex is recommended as an anatomic landmark, and 0 to 3 degrees might be "safe zones" of the sagittal flexion of FC in TKA. This study reflects the level of evidence III.

Modeling Progressive Damage and Failure of Single-Lap Thin-Ply-Laminated Composite-Bolted Joint Using LaRC Failure Criterion.

Thin-ply composite failure modes also significantly differ from conventional ply composite failure modes, with the final failure mechanism switching from irregular progressive failure to direct fracture characterized by a uniform fracture with the reduction of the ply thickness. When open holes and bolt joints are involved, thin-ply-laminated composites exhibit more complex stress states, damage evolution, and failure modes. Compared to the experimental study of thin-ply-laminated composite-bolted joints, there are few reports about numerical analysis. In order to understand the damage evolution and failure mechanism of thin-ply-laminated composites jointed by single-lap bolt, a progressive damage model based on three-dimensional (3D) LaRC failure criterion combined with cohesive element is constructed. Through an energy-based damage evolution method, this model can capture some significant mechanical characteristics in thin-ply-laminated structures, such as the in situ effect, delamination inhibition, and fiber compressive kinking failure. The comparisons between the numerical predictions and experimental observations are made to verify the accuracy of the proposed model. It is found that the predicted stress-displacement curves, failure modes, damage morphologies, etc., are consistent with the experimental results, indicating that the presented progressive damage analysis method displays excellent accuracy. The predicted stress at the onset of delamination is 50% higher than that of the conventional thick materials, which is also consistent with experimental results. Moreover, the numerical model provides evidence that the microstructure of thin-ply-laminated composite performs better in uniformity, which is more conducive to inhibiting the intra-layer damage and the expansion of delamination damage between layers. This study on the damage inhibition mechanism of thin-ply provides a potential analytical tool for evaluating damage tolerance and bearing capabilities in thin-ply-laminated composite-bolted joints.

Pro-angiogenic activity of isofuran.

Isofurans (IsoFs) are a series of novel discovered lipid peroxidation products. This study focused on the investigation of the angiogenic property of IsoF. MTT stain assay indicated that 1 µm IsoF had the most bioactivity in rat brain endothelial cells (RBECs). IsoF significantly promoted cellular proliferation and migration and remarkably decreased staurosporine-induced apoptosis by TUNEL assay in the RBECs. It successfully up-regulated rat aortic vascularization and choroid explant sprouting, extracellular regulated protein kinases (ERK)1/2, and triggered calcium release. RT-PCR examination indicated that IsoF up-regulated tumor necrosis factor (TNF)α, angiopoietin-1 receptor (Tie2), and vascular endothelial growth factor (VEGF)-A, but did not interfere with caspase 2 and VEGF-C in the RBECs. IsoF has pro-angiogenic activity. Calcium release and ERK1/2 phosphorylation may be involved in the signaling of the IsoF-induced up-regulation of TNFα, Tie2, and VEGF-A, which could be the molecular mechanism of the pro-angiogenic activity of the IsoF.

2D materials for bone therapy.

Due to their prominent physicochemical properties, 2D materials are broadly applied in biomedicine. Currently, 2D materials have achieved great success in treating many diseases such as cancer and tissue engineering as well as bone therapy. Based on their different characteristics, 2D materials could function in various ways in different bone diseases. Herein, the application of 2D materials in bone tissue engineering, joint lubrication, infection of orthopedic implants, bone tumors, and osteoarthritis are firstly reviewed comprehensively together. Meanwhile, different mechanisms by which 2D materials function in each disease reviewed below are also reviewed in detail, which in turn reveals the versatile functions and application of 2D materials. At last, the outlook on how to further broaden applications of 2D materials in bone therapies based on their excellent properties is also discussed.

Inorganic polyphosphates stimulates matrix production in human annulus fibrosus cells.

INTRODUCTION: Ubiquitously found in all life forms, inorganic polyphosphates (polyP) are linear polymers of repeated orthophosphate units. Present in intervertebral disc tissue, polyP was previously shown to increase extracellular matrix production in nucleus pulposus (NP) cells. However, the effects of polyP on human annulus fibrosus (hAF) cell metabolism is not known. METHODS AND RESULTS: Here, hAF cells cultured in the presence of 0.5 to 1 mM polyP, chain length 22 (polyP-22), showed an increase in glycosaminoglycan content, proteoglycan and collagen synthesis, and aggrecan and collagen type 1 gene expression. Gene expression level of matrix metalloproteinases 1 was reduced while matrix metalloproteinases 3 level was increased in hAF cells treated with 1 mM polyP. Adenosine triphosphate (ATP) synthesis was also significantly increased in hAF cell culture 72 hours after the exposure to 1 mM polyP-22. CONCLUSIONS: PolyP thus has both anabolic and bioenergetic effects in AF cells, similar to that observed in NP cells. Together, these results suggest polyP as a potential energy source and a metabolic regulator of disc cells.

Advanced nanomaterials for hypoxia tumor therapy: challenges and solutions.

In recent years, nanomaterials and nanotechnology have emerged as vital factors in the medical field with a unique contribution to cancer medicine. Given the increasing number of cancer patients, it is necessarily required to develop innovative strategies and therapeutic modalities to tackle hypoxia, which forms a hallmark and great barrier in treating solid tumors. The present review details the challenges in nanotechnology-based hypoxia, targeting the strategies and solutions for better therapeutic performances. The interaction between hypoxia and tumor is firstly introduced. Then, we review the recently developed engineered nanomaterials towards multimodal hypoxia tumor therapies, including chemotherapy, radiotherapy, and sonodynamic treatment. In the next part, we summarize the nanotechnology-based strategies for overcoming hypoxia problems. Finally, current challenges and future directions are proposed for successfully overcoming the hypoxia tumor problems.

Large-Magnitude Transformable Liquid-Metal Composites.

Most of the existing robots would find it difficult to stretch and transform all parts of their body together due to rigid components and complex actuation mechanisms inside. Here, we presented a highly transformable liquid-metal composite (LMC) that is easy to change shape in large magnitude and resume its original state again according to need. When subject to heating, part of the ethanol droplets embedded in the composite would change phase and then actuate. We demonstrate the flexible transformation of LMC-made octopus from a two-dimensional shape into several predictable three-dimensional shapes freely on a large scale (even up to 11 times its initial height) through remote wireless heating, which needs no sophisticated operating system at all. Further, several designed behaviors, such as movement of octopus and entangling objects of soft robots, are also realized. Theoretical analysis of the heating-induced liquid-vapor transition of the embedded ethanol droplet interprets the mechanisms involved. The present findings open a new way to fabricate functional transformable composites that would find significant applications in developing future generation soft robots.

Biomechanical Analysis of Wide Posterior Releases Compared With Inferior Facetectomy and Discectomy in the Thoracolumbar and Lumbar Spine.

STUDY DESIGN: In vitro biomechanical analysis. OBJECTIVES: Compare the destabilizing effects of anterior discectomy to posterior spinal releases. SUMMARY OF BACKGROUND DATA: Posterior release and pedicle screw fixation has become the accepted form of treatment for lumbar and thoracolumbar pediatric scoliotic spinal deformity. A biomechanical evaluation of posterior releases with comparison to traditional anterior releases has not been reported in the lumbar spine. METHODS: Eleven fresh-frozen human thoracolumbar specimens (T9-L5) were tested by a robotic manipulator (Staubli RX90; moment target of 5.0 Nm, force target of 50 N) in axial rotation (AR), plus lateral and anterior translation (LT and AT). Specimens underwent either sequential anterior release (partial and full discectomy) or posterior release (inferior facetectomy and wide posterior release) from T10 to L4. Partial discectomy retained the posterior 50% of disc and posterior longitudinal ligament, whereas full discectomy removed all of the disc and PLL. Wide posterior release included total facetectomy plus ligamentum flavum and spinous process resection. RESULTS: Inferior facetectomy produced an average increase of 1.5° ± 1.0° (p = .0625), 1.0 ± 0.8 mm (p = .0313), and 0.2 ± 0.3 mm (p = .156) in AR, LT, and AT, respectively. Compared with partial facetectomy, wide posterior release produced an average additional increase of 8.1° ± 4.0° (p = .0312), 2.0 ± 2.2 mm (p = .4062), and 1.1 ± 1.0 mm (p = .0625) in AR, LT, and AT, respectively. Full discectomy produced 201%, 161%, and 153% of the motion relative to wide posterior release in AR, LT, and AT, respectively (p = .0043, .0087, and .0173). Partial discectomy and wide posterior release proved statistically equivalent. CONCLUSIONS: Wide posterior release of the thoracolumbar spine allows significant correction and may be superior to inferior facetectomy in axial rotation. Although complete discectomy with PLL resection would likely allow greater correction, a more clinically realistic partial discectomy confers similar corrective potential in vitro compared with wide posterior release. LEVEL OF EVIDENCE: Not applicable.

A Highly Stretchable Liquid Metal Polymer as Reversible Transitional Insulator and Conductor.

Materials with a temperature-controlled reversible electrical transition between insulator and conductor are attracting huge attention due to their promising applications in many fields. However, most of them are intrinsically rigid and require complicated fabrication processes. Here, a highly stretchable (680% strain) liquid metal polymer composite as a reversible transitional insulator and conductor (TIC), which is accompanied with huge resistivity changes (more than 4 × 109 times) reversibly through a tuning temperature in a few seconds is introduced. When frozen, the insulated TIC becomes conductive and recovers after warming. Both the phase change of the liquid metal droplets and the rigidity change of the polymer contribute directly to transition between insulator and conductor. A simplified model is established to predict the expansion and connection of liquid metal droplets. Along with high stretchability, straightforward fabrication methods, rapid triggering time, large switching ratio, good repeatability, the TIC offers tremendous possibilities for numerous applications, like stretchable switches, semiconductors, temperature sensors, and resistive random-access memory. Accordingly, a system that can display numbers and letters via converting alternative TIC temperature to a binary signal on a computer is conceived and demonstrated. The present discovery suggests a general strategy for fabricating and stimulating a stretchable transitional insulator and conductor based on liquid metal and allied polymers.

Effectiveness of intra-articular ozone injections on outcomes of post-arthroscopic surgery for knee osteoarthritis.

The purpose of the present study was to evaluate intra-articular ozone injection following arthroscopic surgery for knee osteoarthritis (OA) with regard to its efficacy in pain reduction, joint function and quality of life improvement. The present study retrospectively evaluated 80 patients with symptomatic knee OA (Kellgren-Lawrence grade II or III), who either did or did not receive 20 ml of 20 µg/ml ozone as an intra-articular injection after arthroscopic surgery. The minimum follow-up period was 12 months. The outcomes evaluated for knee OA were pain on the Visual Analogue Scale (VAS), Lequesne Index, Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) and Clinical Global Impression (CGI). The VAS score in the ozone group was significantly better than that in the control group at all post-operative follow-up time-points (P<0.05). The ozone group also exhibited a significantly greater improvement in Lequesne Index scores (P<0.05). In the ozone group, the score on the WOMAC-pain, WOMAC-stiffness and WOMAC-function subscales, as well as the total WOMAC score decreased significantly (P<0.05). Furthermore, in the ozone group a significantly higher number of patients (P<0.05) with better CGI grades was encountered compared with that in the control group at the 12-month follow-up assessment, despite comparable baseline values in all aforementioned clinical measures between the two groups of patients. The present study suggests that intra-articular ozone injections after arthroscopic surgery may effectively improve the outcomes of arthroscopic surgery in terms of pain relief, functional improvement and quality of life in patients with knee OA of Kellgren-Lawrence grade II or III.

High­dose folic acid improves endothelial function by increasing tetrahydrobiopterin and decreasing homocysteine levels.

The aim of this study was to investigate the effect of folic acid (FA) on tetrahydrobiopterin (BH4), neopterin, nitric oxide (NO) and homocysteine (Hcy) levels in endothelial cells. Human umbilical vein endothelial cells (HUVECs) were cultured in vitro in the presence or absence of Hcy. The effect of various doses of FA on Hcy, BH4, neopterin and NO concentrations in HUVECs was then assessed. In the 5 and 10 nmol/l FA treatment groups, FA was found to significantly increase the levels of BH4 (10.56±3.86 and 11.23±2.1919 pmol/g vs 6.32+2.87 nmol/g; P<0.05 vs. control) and NO production (37.86±12.34 nmol/l, 38.45±11.23 nmol/l vs 26.21±9.24 nmol/l; P<0.001 vs. paired Hcy group), but reduce the levels of Hcy (132.87±29.67 and 140.87±26.76 nmol/l vs. 165.23±30.56 nmol/l; P<0.05 vs. Hcy group). No significant differences were observed in neopterin levels among the different groups of HUVECs. In conclusion, high doses of FA may be capable of protecting endothelial cells through reducing levels of Hcy and increasing BH4 and NO production.