Combined Molybdenum Gelatine Methacrylate Injectable Nano-Hydrogel Effective Against Diabetic Bone Regeneration.

Introduction: Bone defects in diabetes mellitus (DM) remain a major challenge for clinical treatment. Fluctuating glucose levels in DM patients lead to excessive production of reactive oxygen species (ROS), which disrupt bone repair homeostasis. Bone filler materials have been widely used in the clinical treatment of DM-related bone defects, but overall they lack efficacy in improving the bone microenvironment and inducing osteogenesis. We utilized a gelatine methacrylate (GelMA) hydrogel with excellent biological properties in combination with molybdenum (Mo)-based polyoxometalate nanoclusters (POM) to scavenge ROS and promote osteoblast proliferation and osteogenic differentiation through the slow-release effect of POM, providing a feasible strategy for the application of biologically useful bone fillers in bone regeneration. Methods: We synthesized an injectable hydrogel by gelatine methacrylate (GelMA) and POM. The antioxidant capacity and biological properties of the synthesized GelMA/POM hydrogel were tested. Results: In vitro, studies showed that hydrogels can inhibit excessive reactive oxygen species (ROS) and reduce oxidative stress in cells through the beneficial effects of pH-sensitive POM. Osteogenic differentiation assays showed that GelMA/POM had good osteogenic properties with upregulated expression of osteogenic genes (BMP2, RUNX2, Osterix, ALP). Furthermore, RNA-sequencing revealed that activation of the PI3K/Akt signalling pathway in MC3T3-E1 cells with GelMA/POM may be a potential mechanism to promote osteogenesis. In an in vivo study, radiological and histological analyses showed enhanced bone regeneration in diabetic mice, after the application of GelMA/POM. Conclusion: In summary, GelMA/POM hydrogels can enhance bone regeneration by directly scavenging ROS and activating the PI3K/Akt signalling pathway.

Estimation of the global prevalence, incidence, years lived with disability of rheumatoid arthritis in 2019 and forecasted incidence in 2040: results from the Global Burden of Disease Study 2019.

OBJECTIVE: We aimed to provide a better understanding of the secular trends in rheumatoid arthritis (RA) burden at the regional and national levels, contributing to identifying the areas with high burden needs and finding the potential areas requiring additional attention, which will facilitate the development of strategies tailored to RA burden. METHOD: Data were obtained from the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2019 study. We presented the secular trends in the prevalence, incidence, and years lived with disability (YLDs) of RA needs by sex, age, sociodemographic index (SDI), region, country, and category between 1990 and 2019 using data from the GBD 2019 study. The age-standardized rates (ASR) and its estimated annual percentage changes (EAPCs) are employed to describe the secular trends in RA. RESULTS: Globally, there were an estimated 18.5 million [95% confidence interval (CI) 31.53 to 41.74)] prevalent cases of RA, with 1.07 million (95% CI 0.95 to 1.18) incident cases per year and almost 2.43 million YLDs (95% CI 1.68 to 3.28) in 2019. The age-standardized prevalence and incidence rates estimated for RA were 224.25 per 100,000 and 12.21 per 100,000 in 2019, with EAPCs of 0.37 (95% CI - 0.32, 0.42) and 0.30 (95% CI 0.25 to 0.34), respectively. The corresponding age-standardized YLDs estimated was 29.35 per 100,000 in 2019, with an EAPC of 0.38 (95% CI: 0.33, 0.43). During the study period, the ASR of RA was consistently higher in females than in males. Moreover, the age-standardized YLD rate of RA was associated with the sociodemographic index (SDI) in 2019 across all 204 countries and territories (R = 0.28). The projections indicate that the age-standardized incidence rates (ASIR) trend will continue to increase from 2019 to 2040, with a projected ASIR of 10.48 and 4.63/100,000 for females and males, respectively. CONCLUSIONS: RA is prevalent and remains a significant global public health challenge. Globally, the burden of RA has increased over the past 30 years and will continue to increase. Prevention and early treatment of RA are pivotal to avoiding disease onset and alleviating the enormous burden. Key Points • The burden of rheumatoid arthritis is increasing globally. • Global estimates indicate that the number of RA incident cases will increase 1.4-fold globally, from approximately 1.07 million at the end of 2019 to approximately 1.5 million by 2040.

Correlation between sedentary activity, physical activity and bone mineral density and fat in America: National Health and Nutrition Examination Survey, 2011-2018.

We compared the relationship between sedentary activity (SA) and physical activity (PA) with bone mineral density (BMD) and body fat percentage in the United States and found a negative association between SA and BMD and a positive association with body fat percentage. A positive association between PA and BMD and a negative association with body fat percentage. SA and PA are associated with changes in skeletal parameters and body fat percentage, and we aimed to investigate and compare the relationship between SA, PA and bone mineral density (BMD) and body fat percentage in men and women. We assessed the relationship between SA, PA and BMD and body fat percentage in 9787 Americans aged 20-59 years (mean age 38.28 ± 11.39 years) from NHANES 2011-2018. BMD and body fat percentage were measured by dual-energy X-ray bone densitometry (DXA). We used multiple linear regression models to examine the relationships between SA, PA and lumbar spine BMD and total body fat percentage, adjusted for a large number of confounding factors. After adjusting for race/ethnicity, age, alcohol and smoking behavior, body mass index (BMI), total protein, blood calcium, blood uric acid, cholesterol, blood phosphorus, vitamin D, and blood urea nitrogen, SA was negatively associated with lumbar spine BMD (ß = - 0.0011 95% CI - 0.0020 to - 0.0002, P = 0.022), and SA was positively associated with total fat percentage (ß = PA was positively associated with lumbar BMD (ß = 0.0046 95% CI 0.0010 to 0.0082, P = 0.012) and there was a negative association between PA and body fat percentage (ß = - 1.177 95% CI - 1.326 to -1.027, P < 0.001). Our results show that physical activity is a key component of maintaining bone health in both men and women and is strongly associated with lower body fat percentages. Sedentary activity is negatively correlated with bone density and is strongly associated with an increase in body fat percentage. Healthcare policy makers should consider reducing sedentary activity and increasing physical activity when preventing osteoporosis and obesity.

3D mapping of intra-articular calcaneal fractures.

To determine the pattern of intra-articular calcaneal fractures (ICFs) by a three-dimensional (3D) mapping and determine whether there were consistent fracture patterns and comminution zones. In this study, 67 patients with ICFS by CT scan were included. The calcaneal fractures fragments in CT were multiplanar reconstructed and virtual reduced. 3D heat mapping was subsequently created by graphically superimposing all fracture lines onto a standard calcaneal template. The cohort included 26 (38.8%) left calcaneal fractures, 27 (40.30%) right calcaneal fractures, and 14 (20.9%) cases with bilateral fractures. Comminuted fractures accounted for 92.5%. Sagittal 3D mapping shows that the fracture line is mainly concentrated at the critical angle of Gissane and extending rear to the posterior of the tuberosity of the lateral wall and the anterior of the medial process of the calcaneus tuberosity but with more significant variation in the medial wall. The average angle of fracture lines concerning the long calcaneal axis (LCA) was 29.1° and 19.2° in the lateral and medial walls. Axial 3D mapping shows that fracture lines were primarily concentrated in the anterior area to the posterior joint facet and extending along the rear joint facet and calcaneus sulcus to the posteriorly of the tuberosity. The mean angle of fracture lines concerning the LAC was 11° in the axial wall. Our data provided elucidated that ICFs have consistent characteristic fracture patterns and comminution zones. This study provides visual guidelines for understanding fracture morphology, which may assist with fracture classification, preoperative planning, development of fixation concepts.

Rereferencing of clinical EEGs with nonunipolar mastoid reference to infinity reference by REST.

OBJECTIVE: Conventional electroencephalography (EEG) offline subtraction rereferencing is invalid for many clinical practices when adopting a specific nonunipolar recording montage (e.g., the ipsilateral mastoid (IM) and contralateral mastoid (CM)). Further comparative analyses would thus be blocked due to the lack of a uniform offline reference. Therefore, our goal was to resolve this problem by introducing and assessing the reference electrode standardization technique (REST) to transform nonunipolar mastoid montages into a computational zero reference at infinity (IR) offline. METHODS: For EEG signals and power/connectivity configurations, simulation and clinical schizophrenia resting-state EEG datasets were used to investigate the performance of REST. RESULTS: REST produced small absolute errors (signal level: 1.21-1.26; power: 0.0057-0.021; connectivity: 0.066-0.088) and high correlations (>0.9) between the IM/CM-IR and true IR references. Using clinical data with the IM online reference, REST revealed valuable changes in spectral and connectivity (P < 0.05) in schizophrenia patients, consistent with previous studies. CONCLUSIONS: These results demonstrated that REST transformation could be adopted to resolve the offline rereferencing of clinical EEGs with specific nonunipolar mastoid references. SIGNIFICANCE: REST could be an effective and robust resolution for nonunipolar clinical EEGs and could therefore retrieve these data for further analysis by deriving a favorable offline reference IR.

NIR-responsive molybdenum (Mo)-based nanoclusters enhance ROS scavenging for osteoarthritis therapy.

Osteoarthritis (OA) is one of the most prevalent musculoskeletal disorders globally, and treating OA remains a significant challenge. Currently, pharmacological treatments primarily aim to alleviate the OA symptoms associated with inflammation and pain, and no disease-modifying therapies are available to delay OA development and progression. Reactive oxygen species (ROS) play an essential role in OA development and progression, which are a promising target for curing OA. In this study, it was found that photothermal properties of near-infrared (NIR) irradiation enhanced the ROS scavenging activity of molybdenum-based polyoxometalate (POM) nanoclusters. Because of enhanced ROS scavenging, NIR-responsive POM nanoclusters were developed as novel excellent nano-antioxidants for OA protection. The results demonstrated that NIR-responsive POM exhibited outstanding antioxidant activity and superexcellent anti-inflammatory effects, which could effectively alleviate the clinical symptoms of OA mice, diminish inflammatory cytokines, reduce catabolic proteases, and mitigate the progression of OA. Meanwhile, the local treatment had no side effects on normal tissues. Thus, this study pioneered the application of POM for alleviating OA with expected safety and efficiency.

Two and three-dimensional CT mapping of the sustentacular fragment in intra-articular calcaneal fractures.

The sustentaculum tali are tightly bound to the talus by the interosseous and deltoid ligament complex and have been considered a ''constant fragment". Yet there is a dearth of study on the anatomical patterns of the sustentacular segment. Consequently, this study is designated with the purpose of defining the prevalence and displacement of sustentacular fractures in intra-articular calcaneal fractures (ICFs) applying computed tomography (CT) mapping in both two-dimensional (2D) and three-dimensional (3D) conditions. From January 2019 to December 2020, the CT images of sixty-seven patients with eighty-one ICFs were retrospectively evaluated, besides, basic patient demographics and mechanisms of injury were documented. And the prevalence of sustentacular fractures was characterized in the sagittal or coronal CT planes. The subluxation, angulation, and translation of the portion of the sustentacular bone were noted. By decreasing rebuilt fracture fragments to suit a model of the sustentaculum tali, a 3D map was generated. Overall, the sustentacular fracture in 21 (25.9%) of the 81 ICFs, 15 (71.4%) were nondisplaced, 6 (28.6%) were displaced, and mean coronal angulation was 21.9°, and no comminuted. The relationship between sustentaculum tali and the talus was anatomically aligned in 71 (87.7%), and subluxation in 10 (12.3%). According to the research, 3D mapping demonstrated that most fracture lines start from the anterior of the sustentaculum tali, extending obliquely to the sulcus of the flexor halluces longus tendon. Moreover, this study provides a detailed description (displacement or articular dislocation) of the frequency of sustentacular fragments in ICFs. The finding disproves the ''constant'' theory of the sustentacular fragments, due to the fact that comminuted fracture of sustentaculum tali was rare. And the expertise of these fracture patterns may affect the progress of fixation concepts and surgical approaches. Moreover, we further speculated that the displacement of the sustentacular fragment was considerably more probable to emerge in the higher-order Sanders classification. Nevertheless, bigger sample size is required to further validate this position.

NR2F2 Regulates Cell Proliferation and Immunomodulation in Whartons' Jelly Stem Cells.

(1) Background: Wharton's Jelly stem cells (WJ-MSCs) are multipotent mesenchymal stem cells that can proliferate rapidly and have low immunogenicity. Therefore, WJ-MSCs have gained considerable attention in the fields of immunomodulation and disease treatment and have entered clinical trials for the treatment of various diseases. Therefore, it is crucial to study the underlying mechanisms of WJ-MSCs proliferation, immune regulation, and disease treatment. Nuclear Receptor Subfamily 2 Group F Member 2 (NR2F2) is a transcription factor that is involved in the regulation of many different genes. However, it remains unknown how NR2F2 regulates stem cell identity in WJ-MSCs. (2) Methods: We used RNAi technology to knock down NR2F2 in WJ-MSCs, and studied the regulatory role of NR2F2 in WJ-MSCs by MTT, flow cytometry, RNA-seq, and other methods. We also utilized a co-culture system in which NR2F2-depleted WJ-MSCs with MH7A and HCT116/HepG2 were used to investigate the role of NR2F2 in immunomodulation and the inhibition of cancer cell growth. (3) Results: NR2F2 knockdown resulted in decreased expressions of Cyclin D1 and CDK4, slower cell proliferation, and increased expressions of IL6 and IL8. Furthermore, Cyclin D1, CDK4, and inflammatory factors were increased in human rheumatoid fibroblast-like synoviocyte line MH7A if co-cultured with NR2F2 depleted WJ-MSCs. In addition, we observed increased p53, decreased BCL-2, and increased cell apoptosis in liver cancer cell line HepG2 if co-cultured with NR2F2-depleted WJ-MSCs. (4) Conclusions: NR2F2 not only plays an important role in the cell cycle and immune regulation of WJ-MSCs but also has potential effects on the WJ-MSCs treatment of related diseases.

3D printing-assisted extended lateral approach for displaced intra-articular calcaneal fractures: a systematic review and meta-analysis.

BACKGROUND: Three-dimensional (3D) printing technology has developed rapidly in orthopaedic surgery and effectively achieves precise and personalized surgery. The purpose of this meta-analysis was to assess the efficacy of 3D printing technology in the management of displaced intra-articular calcaneal fractures (DICFs) by extended lateral approach (ELA). METHODS: We searched PubMed, Web of Science, Embase, Cochrane Library, CNKI, VIP, and VANFUN databases were searched up to October 2020. All clinical studies comparing traditional surgery and 3D printing-assisted surgery in the management of DICFs were obtained, evaluating the quality of the included studies and extracting data. For each study, we assessed odds ratios (ORs), standard mean difference (SMD), and 95% confidence interval (95% CI) to assess and synthesize the outcomes. RESULTS: Three RCTs and nine retrospective studies involving 732 patients were included met our inclusion criteria with 366 patients in the 3D group and 366 patients in the conventional group. The meta-analysis showed that there were significant differences of the operative time in the 3D group [SMD = - 1.86, 95% CI (- 2.23, - 1.40), P < 0.001], intraoperative blood loss [SMD = - 1.26, 95% CI (- 1.82, - 0.69), P < 0.001], the number of intraoperative X-ray exposures [SMD = - 0.66, 95% CI (- 1.20, - 0.12), P < 0.001], postoperative complications [OR = 0.49, 95% CI (0.31, 0.79), P < 0.001], excellent and good rate of calcaneal fracture outcome [OR = 4.09, 95% CI (2.03, 8.22), P < 0.001]. CONCLUSION: The current study indicates that 3D printing-assisted ELA surgery showed a better rate of excellent and good outcome, shorter operation time, less intraoperative blood loss, fewer intraoperative fluoroscopies, fewer complications. Besides, there is still a need for large-sample, high-quality, long-term randomized controlled trials to confirm the conclusion.

Schwann cells promote prevascularization and osteogenesis of tissue-engineered bone via bone marrow mesenchymal stem cell-derived endothelial cells.

BACKGROUND: Tissue-engineered bone grafts (TEBGs) that undergo vascularization and neurotization evolve into functioning bone tissue. Previously, we verified that implanting sensory nerve tracts into TEBGs promoted osteogenesis. However, the precise mechanisms and interaction between seed cells were not explored. In this study, we hypothesized that neurotization may influence the osteogenesis of TEBGs through vascularization. METHODS: We cultured rat Schwann cells (SCs), aortic endothelial cells (AECs), and bone marrow-derived mesenchymal stem cells (BM-MSCs) and then obtained BM-MSC-derived induced endothelial cells (IECs) and induced osteoblasts (IOBs). IECs and AECs were cultured in an SC-conditioned medium (SC-CM) to assess proliferation, migration, capillary-like tube formation, and angiogenesis, and the vascular endothelial growth factor (VEGF) levels in the supernatants were detected. We established an indirect coculture model to detect the expression of nestin and VEGF receptors in IECs and tissue inhibitor of metalloproteinase (TIMP)-2 in SCs. Then, SCs, IECs, and IOBs were labeled and loaded into a ß-tricalcium phosphate scaffold to induce prevascularization, and the scaffold was implanted into a 6-mm-long defect of rat femurs. Three groups were set up according to the loaded cells: I, SCs, and IECs (coculture for 3 days) plus IOBs; II, IECs (culture for 3 days) plus IOBs; III, IOBs. Nestin and TIMP-2 expression and osteogenesis of TEBGs were evaluated at 12 weeks post-implantation through histological and radiological assessments. RESULTS: We found that SC-CM promoted IEC proliferation, migration, capillary-like tube formation, and angiogenesis, but no similar effects were observed for AECs. IECs expressed nestin extensively, while AECs barely expressed nestin, and SC-CM promoted the VEGF secretion of IECs. In the coculture model, SCs promoted nestin and VEGF receptor expression in IECs, and IECs inhibited TIMP-2 expression in SCs. The promotion of prevascularized TEBGs by SCs and IECs in group I augmented new bone formation at 6 and 12 weeks. Nestin expression was higher in group I than in the other groups, while TIMP-2 expression was lower at 12 weeks. CONCLUSIONS: This study demonstrated that SCs can promote TEBG osteogenesis via IECs and further revealed the related specific characteristics of IECs, providing preliminary cytological evidence for neurotization of TEBGs.

[Technical summary and modified instruments of free vascularized fibular grafting for osteonecrosis of femoral head].

Objective: To summarize retrospectively the clinical technology of repairing osteonecrosis of femoral head (ONFH) by free vascularized fibular grafting (FVFG), and the value of modified instruments in operation. Methods: Between March 2011 and January 2013, 35 patients with ONFH (47 hips) who underwent FVFG with modified instruments. There were 24 males (32 hips) and 11 females (15 hips), aged 34 years on average (range, 22-43 years). The unilateral hip was involved in 23 cases and the bilateral hips in 12 cases. The disease duration ranged from 5 to 9 months (mean, 7 months). Based on etiology, 25 hips were classified as alcohol ONFH, 12 hips as corticosteroids ONFH, 3 hips as trauma ONFH, and 7 hips as idiopathic ONFH. According to the Association Research Circulation Osseous(ARCO) stage, 3 hips were rated as stage I, 39 hips as stage II, and 5 hips as stage III on the X-ray films. The preoperative Harris score was 58.2±6.1. Results: The time to get fibula was 15-35 minutes (mean, 25 minutes). The operation time was 90-200 minutes (mean, 130 minutes), and the blood loss during operation was 150-500 mL (mean, 270 mL). All the patients achieved primary healing of incision, without complication of infection or deep vein thrombosis. All 35 patients were followed up 12-42 months, with an average of 28 months. The Harris score at final follow-up was 87.3±5.7, showing significant difference when compared with preoperative score ( t=102.038, P=0.000). Radiographic results at final follow-up showed good position of fibula; and necrosis was improved in 9 hips, had no changes in 36 hips, and aggravated in 2 hips. Conclusion: FVFG for ONFH can improve hip function effectively, and modified instruments can improve operation efficiency.

[Effects of Schwann cells promoting nitric oxide secretion of bone marrow mesenchymal stem cells derived endothelial cells].

OBJECTIVE: To study the effect of Schwann cells (SCs) promoting the function of nitric oxide (NO) secretion of bone marrow mesenchymal stem cells (BMSCs) derived endothelial cells so as to lay the experimental foundation for research of the effect of nerves on vessels during the process of tissue engineering bone formation. METHODS: SCs were collected from 1-day-old Sprague Dawley (SD) rats, and identified through S100 immunohistochemistry (IHC). BMSCs were collected from 2-week-old SD rats and induced into endothelial cells (IECs), which were identified through von Willebrand factor (vWF) and CD31 immunofluorescence (IF). Transwell system was used for co-culture of SCs and IECs without contact as the experimental group, and simple culture of IECs served as the control group. The NO concentration in the medium was measured at 1, 3, 5, and 7 days after culture; the mRNA expressions of nitric oxide synthetase 2 (NOS2) and NOS3 were detected by real-time fluorescence quantitative PCR (RT -qPCR) at 1, 3, 7, and 10 days. RESULTS: SCs and IECs were identified through morphology and immunology indexes of S100 IHC, vWF and CD31 IF. Significant differences were found in the NO concentration among different time points in 2 groups (P < 0.05); the NO concentration of the experimental group was significantly higher than that of the control group at the other time points (P < 0.05) except at 3 days. NOS2 mRNA expression of the experimental group was significantly higher than that of the control group (P < 0.05); difference was significant in the NOS2 mRNA expression among different time points in 2 groups (P < 0.05). NOS3 mRNA expression of the experimental group was significantly higher than that of the control group at the other time points (P < 0.05) except at 10 days. No significant difference was found in NOS3 mRNA expression among different time points in the experimental group (F = 6.673, P = 0.062), but it showed significant differences in the control group (F = 36.581, P = 0.000). CONCLUSION: SCs can promote NO secretion of BMSCs derived endothelial cells, which is due to promoting the activity of NOS.