Risk assessment and clinical prediction model of planned transfer to the ICU after hip arthroplasty in elderly individuals.

BACKGROUND: With the development of hip arthroplasty technology and rapid rehabilitation theory, the number of hip arthroplasties in elderly individuals is gradually increasing, and their satisfaction with surgery is also gradually improving. However, for elderly individuals, many basic diseases, poor nutritional status, the probability of surgery, anaesthesia and postoperative complications cannot be ignored. How to reduce the incidence of postoperative complications, optimize medical examination for elderly patients, and reasonably allocate medical resources. This study focuses on the construction of a clinical prediction model for planned transfer to the ICU after hip arthroplasty in elderly individuals. METHODS: We retrospectively analysed 325 elderly patients who underwent hip arthroplasty. The general data and preoperative laboratory test results of the patients were collected. Univariate and multivariate logistic regression analyses were performed to screen independent influencing factors. The backwards LR method was used to establish the prediction model. Then, we assessed and verified the degree of discrimination, calibration and clinical usefulness of the model. Finally, the prediction model was rendered in the form of a nomogram. RESULTS: Age, blood glucose, direct bilirubin, glutamic-pyruvic transaminase, serum albumin, prothrombin time and haemoglobin were independent influencing factors of planned transfer to the ICU after hip arthroplasty. The area under the curve (AUC) of discrimination and the 500 bootstrap internal validation AUC of this prediction model was 0.793. The calibration curve fluctuated around the ideal curve and had no obvious deviation from the ideal curve. When the prediction probability was 12%-80%, the clinical decision curve was above two extreme lines. The discrimination, calibration and clinical applicability of this prediction model were good. The clinical prediction model was compared with the seven factors in the model for discrimination and clinical use. The discrimination and clinical practicability of this prediction model were superior to those of the internal factors. CONCLUSION: The prediction model has good clinical prediction ability and clinical practicability. The model is presented in the form of a linear graph, which provides an effective reference for the individual risk assessment of patients.

YBX1 Promotes MSC Osteogenic Differentiation by Activating the PI3K/AKT Pathway.

INTRODUCTION: Bone metabolism has an essential role in bone disease, but its specific mechanism remains unclear. Y-Box Binding Protein 1 (YBX1) is a gene with broad nucleic acid binding properties, which encodes a highly conserved cold shock domain protein. Previous studies have shown that YBX1 is closely related to cell differentiation. However, the function of YBX1 in osteoblast differentiation of bone marrow mesenchymal stem cells (MSCs) was unclear. METHODS: To explore the effect and specific mechanism of YBX1 in osteogenic differentiation of MSCs, we used PCR, Western blot, Alizarin red Staining, alkaline phosphatase (ALP) assays, and siRNA knockdown in our research. We found that YBX1 gradually increased during the process of osteogenic differentiation of MSCs. YBX1 siRNA could negatively regulate the MSCs osteogenic differentiation. Mechanistic studies revealed that YBX1 knockdown could inhibit PI3K/AKT pathway. Furthermore, the specific agonist (SC79) of PI3K/AKT pathway could restore the impaired MSCs osteogenic differentiation which was mediated by YBX1 knockdown. Taken together, we concluded that YBX1 could positively regulate the osteogenic differentiation of MSCs by activating the PI3K/AKT pathway. RESULTS AND DISCUSSION: These results helped us further understand the mechanism of osteogenesis and revealed that YBX1 might be a selectable target in the bone repair field. CONCLUSION: Our study provides a new target and theoretical basis for the treatment of bone diseases.

The impact of CRMP4 SUMOylation on the Cav1.2 interaction, neurite outgrowth and thermal pain sensitivity.

Collapsin response mediator protein 4 (CRMP4) is critical for neuronal development. However, whether CRMP4 could be SUMOylated and how the SUMOylation regulates the interaction with the L-type voltage-gated calcium channel (Cav1.2), neurite outgrowth, and thermal pain sensitivity remain to be elucidated. To determine the SUMOylation of CRMP4, Glutathione S-transferase (GST) - Small Ubiquitin-like Modifier 1 (-SUMO1), -SUMO2, and -SUMO3 proteins were purified for GST-pulldown. Immunofluorescence staining was performed to observe colocalization of CRMP4 and SUMOs. Co-immunoprecipitation (co-IP) was performed to assess the interaction between CRMP4 and SUMO2. GST-pulldown and co-IP were performed to verify the interaction between CRMP4 and Cav1.2. The impact of SUMOylation of CRMP4 on its interaction with Cav1.2 was determined. Then, the effect of CRMP4 SUMOylation on neurite outgrowth was observed. Whole-cell patch clamping revealed the effect of CRMP4 SUMOylation on Cav1.2 mediated calcium influx. Paw withdrawal latency was measured to assess the impact of CRMP4 SUMOylation on thermal pain sensitivity in rats. The data revealed that CRMP4 K374 is a potential site for SUMO modification. SUMO1, SUMO2, and SUMO3 can all interact with CRMP4. SUMO2 interacts with CRMP4, but not a variant of CRMP4 harboring a mutation of K374. CRMP4 and SUMO proteins colocalized in neurites, and CRMP4 deSUMOylation promoted neurite outgrowth. CRMP4 interacted with Cav1.2, and deSUMOylation of CRMP4 strengthened this interaction. CRMP4 promoted calcium influx via Cav1.2, and overexpression of CRMP4 significantly increased thermal pain sensitivity in rats, which CRMP4 deSUMOylation strengthened. In conclusion, these data demonstrate the SUMOylation of CRMP4, elucidate the impacts of SUMOylation on the interaction with Cav1.2 on neurite outgrowth and thermal pain sensitivity.

CircHYBID regulates hyaluronan metabolism in chondrocytes via hsa-miR-29b-3p/TGF-ß1 axis.

BACKGROUND: Hyaluronan (HA) metabolism by chondrocytes is important for cartilage development and homeostasis. However, information about the function of circular RNAs (circRNAs) in HA metabolism is limited. We therefore profiled the role of the novel HA-related circRNA circHYBID in the progression of osteoarthritis (OA). METHODS: CircHYBID function in HA metabolism in chondrocytes was investigated using gain-of-function experiments, and circHYBID mechanism was confirmed via bioinformatics analysis and luciferase assays. The expression of circHYBID-hsa-miR-29b-3p-transforming growth factor (TGF)-ß1 axis was examined by quantitative real-time polymerase chain reaction (qRT-PCR) and Western blotting. CircHYBID, TGF-ß1, and HA levels in cartilage samples were evaluated using qRT-PCR and pathological examination. Enzyme-linked immunosorbent assay was used to assess HA accumulation in chondrocyte supernatant. RESULTS: CircHYBID expression was significantly downregulated in damaged cartilage samples compared with that in the corresponding intact cartilage samples. CircHYBID expression was positively correlated with alcian blue score. Interleukin-1ß stimulation in chondrocytes downregulated circHYBID expression and decreased HA accumulation. Gain-of-function experiments revealed that circHYBID overexpression in chondrocytes increased HA accumulation by regulating HA synthase 2 and HYBID expression. Further mechanism analysis showed that circHYBID upregulated TGF-ß1 expression by sponging hsa-miR-29b-3p. CONCLUSIONS: Our results describe a novel HA-related circRNA that could promote HA synthesis and accumulation. The circHYBID-hsa-miR-29b-3p-TGF-ß1 axis may play a powerful regulatory role in HA metabolism and OA progression. Thus, these findings will provide new perspectives for studies on OA pathogenesis, and circHYBID may serve as a potential target for OA therapy.

Inhibited microRNA-218-5p attenuates synovial inflammation and cartilage injury in rats with knee osteoarthritis by promoting sclerostin.

OBJECTIVE: In recent decades, the role of microRNAs (miRNAs) in human diseases has been widely studied. This research is designed to explore the effect of miR-218-5p on knee osteoarthritis (KOA) progression in a rat model with the involvement of sclerostin (SOST). METHODS: The KOA rat models were constructed by Hulth method, and then were classified into the KOA, miR-218-5p inhibitor, inhibitor negative control (NC), overexpressed (OE)-SOST, OE-NC, miR-218-5p inhibitor + si-SOST, or miR-218-5p inhibitor + si-NC group. The pathological changes of rats' synovial tissues were observed; the apoptosis in rat synovial tissues was assessed; levels of IL-1ß, TNF-α, PGE2 and COX-2 in serum and synovial tissues, along with SOD and MDA contents in synovial tissues were determined. The morphological changes in cartilage tissues were observed. MMP-13 and Col II expression in cartilage tissues was assessed; expression of ß-catenin and Col2A1 in cartilage tissues was assessed. miR-218-5p and SOST expression in rat knee joint tissues was assessed. RESULTS: KOA rats had increased miR-218-5p expression and decreased SOST expression. MiR-218-5p targeted SOST. Rats injected with miR-218-5p inhibitor and OE-SOST had alleviated pathological changes, reduced TUNEL positive cell rate, decreased serum contents of IL-1ß, TNF-α, PGE2, COX-2 and MDA, and increased SOD activity in synovial tissues, alleviated pathological changes, enhanced Col II positive rate and reduced MMP-13 positive rate, decreased ß-catenin expression and increased Col2A1 expression in cartilage tissues. CONCLUSION: The miR-218-5p inhibition could attenuate synovial inflammation and cartilage injury in KOA rats by promoting SOST, which may be helpful for KOA treatment.

Dnmt3a-Mediated DNA Methylation Changes Regulate Osteogenic Differentiation of hMSCs Cultivated in the 3D Scaffolds under Oxidative Stress.

Oxidative stress (OS) caused by multiple factors occurs after the implantation of bone repair materials. DNA methylation plays an important role in the regulation of osteogenic differentiation. Moreover, recent studies suggest that DNA methyltransferases (Dnmts) are involved in bone formation and resorption. However, the effect and mechanism of DNA methylation changes induced by OS on bone formation after implantation still remain unknown. Three-dimensional (3D) cell culture systems are much closer to the real situation than traditional monolayer cell culture systems in mimicking the in vivo microenvironment. We have developed porous 3D scaffolds composed of mineralized collagen type I, which mimics the composition of the extracellular matrix of human bone. Here, we first established a 3D culture model of human mesenchymal stem cells (hMSCs) seeded in the biomimetic scaffolds using 160 µM H2O2 to simulate the microenvironment of osteogenesis after implantation. Our results showed that decreased methylation levels of ALP and RUNX2 were induced by H2O2 treatment in hMSCs cultivated in the 3D scaffolds. Furthermore, we found that Dnmt3a was significantly downregulated in a porcine anterior lumbar interbody fusion model and was confirmed to be reduced by H2O2 treatment using the 3D in vitro model. The hypomethylation of ALP and RUNX2 induced by H2O2 treatment was abolished by Dnmt3a overexpression. Moreover, our findings demonstrated that the Dnmt inhibitor 5-AZA can enhance osteogenic differentiation of hMSCs under OS, evidenced by the increased expression of ALP and RUNX2 accompanied by the decreased DNA methylation of ALP and RUNX2. Taken together, these results suggest that Dnmt3a-mediated DNA methylation changes regulate osteogenic differentiation and 5-AZA can enhance osteogenic differentiation via the hypomethylation of ALP and RUNX2 under OS. The biomimetic 3D scaffolds combined with 5-AZA and antioxidants may serve as a promising novel strategy to improve osteogenesis after implantation.

Bone mesenchymal stem cells co-expressing VEGF and BMP-6 genes to combat avascular necrosis of the femoral head.

The aim of the present study was to investigate the potential of bone mesenchymal stem cells (BMSCs) treated with a combination of vascular endothelial growth factor (VEGF) and bone morphogenetic protein-6 (BMP-6) genes for the treatment of avascular necrosis of the femoral head (ANFH). Rat BMSCs were isolated and purified using a density gradient centrifugation method. The purity and characteristics of the BMSCs were detected by cell surface antigens identification using flow cytometry. The experimental groups were administered with one of the following adeno-associated virus (AAV) vector constructs: AAV-green fluorescent protein (AAV-GFP), AAV-BMP-6, AAV-VEGF or AAV-VEGF-BMP-6. The expression of VEGF and BMP-6 was detected by reverse transcription-quantitative polymerase chain reaction, western blotting and ELISA assays. The effects of VEGF and BMP-6 on BMSCs were evaluated by angiogenic and osteogenic assays. The transfected BMSCs were combined with a biomimetic synthetic scaffold poly lactide-co-glycolide (PLAGA) and they were then subcutaneously implanted into nude mice. After four weeks, the implants were analyzed with histology and subsequent immunostaining to evaluate the effects of BMSCs on blood vessel and bone formation in vivo. In the AAV-VEGF-BMP-6 group, the expression levels of VEGF and BMP-6 were significantly increased and human umbilical vein endothelial cells tube formation was significantly enhanced compared with other groups. Capillaries and bone formation in the AAV-VEGF-BMP-6 group was significantly higher compared with the other groups. The results of the present study suggest that BMSCs expressing both VEGF and BMP-6 induce an increase in blood vessels and bone formation, which provides theoretical support for ANFH gene therapy.

An injectable, biodegradable calcium phosphate cement containing poly lactic-co-glycolic acid as a bone substitute in ex vivo human vertebral compression fracture and rabbit bone defect models.

Purpose/Aim of the study: To evaluate the biomechanical characteristics and biocompatibility of an injectable, biodegradable calcium phosphate cement (CPC) containing poly lactic-co-glycolic acid (PLGA). MATERIALS AND METHODS: A vertebral compression fracture model was established using 20 human cadaveric vertebrae (T11-L3) divided into CPC/PLGA composite versus PMMA groups for biomechanical testing. In addition, 35 New Zealand rabbits were used to evaluate biodegradability and osteoconductive properties of CPC/PLGA using a bone defect model. In vitro cytotoxicity was evaluated by culturing with L929 cells. RESULTS: The CPC/PLGA composite effectively restored vertebral biomechanical properties. Compared with controls, the maximum load and compression strength of the CPC/PLGA group were lower, and stiffness was lower after kyphoplasty (all p <.05). Degradation was much slower in the control CPC compared with CPC/PLGA group. The bone tissue percentage in the CPC/PLGA group (44.9 ± 23.7%) was significantly higher compared with control CPC group (25.7 ± 10.9%) (p <.05). The viability of cells cultured on CPC/PLGA was greater than 70% compared with the blanks. CONCLUSIONS: Our biodegradable CPC/PLGA composite showed good biomechanical properties, cytocompatibility, and osteoconductivity and may represent an ideal bone substitute for future applications.

Comparison of the risk of infections in different anti-TNF agents: a meta-analysis.

BACKGROUND: Anti-tumor necrosis factor α (anti-TNF-α) treatments are widely used in patients with rheumatoid arthritis (RA); however, the increased risk of infections is one of the most important side effects of anti-TNF-α agents. This study evaluated the differences between monoclonal antibodies and the soluble receptor for infections in patients with RA by direct comparison of observation studies. METHODS: A systemic literature search was conducted in March 2014 and an up-to-date search was conducted in August 2014. All studies reporting infections in RA patients treated with the soluble receptor (ETA [etanercept]) and at least one of monoclonal antibodies (INF [infliximab], ADA [adalimumab]) were included. RESULTS: Twelve articles were finally included. The meta-analysis revealed that compared with monoclonal antibodies, the soluble receptor had a lower incidence rate of serious infections (relative risk [RR] = 0.63 [0.40-0.97] P = 0.04), but we have to notice that the heterogeneity was high (I2 = 85%) and publication bias might exist. As to tuberculosis, the pooled analysis revealed that the soluble receptor had a lower risk (RR = 0.19 [0.06-0.56] P = 0.003) and its heterogeneity was low (I2 = 0%) while no publication bias was observed. For general infections, ETA had a lower risk compared with mono-antibodies and its heterogeneity was high (RR = 0.66 [0.49-0.89] P < 0.00001 I2 = 79%). CONCLUSION: Compared with mono-antibodies, the soluble receptor has a lower risk for tuberculosis and general infections. But as to serious infections, the answer is uncertain due to its high heterogeneity and possibility of publication bias. More well-designed long-term prospective studies would be important to strengthen these findings.

[In vivo degradable properties of a novel injectable calcium phosphate cement containing poly lactic-co-glycolic acid].

OBJECTIVE: To investigate the in vivo degradable properties of new calcium phosphate cement (CPC) containing poly lactic-co-glycolic acid (PLGA) so as to lay a foundation for the future clinical application. METHODS: A novel CPC containing PLGA (CPC/PLGA) was prepared according to a ratio of 45% dicalcium phosphate anhydrous: 45% partially crystallized calcium phosphates: 10% PLGA. Thirty-two adult New Zealand rabbits (weighing 2.2-3.0 kg, male or female in half) were divided into the experimental group (n = 17) and the control group (n = 15). The bone defect models of the bilateral femoral condyles (4.5 mm in diameter and 1.5 cm in depth) were made by drilling hole. Defect at the right side was repaired with CPC/PLGA in the experimental group and with CPC in the control group, while defect at the left side was not treated as blank control. The general condition of rabbits was observed after operation; the histological observation and bone histomorphometric analysis were performed at 2, 4, 8, 16, and 24 weeks; and scanning electronic microscope (SEM) observation was performed at 8 and 16 weeks after operation. RESULTS: All rabbits survived to the end of experiment. The histological observation showed: CPC/PLGA degraded gradually, and the new-born bone trabecula ingrew; bone trabeculae became rough and strong; and CPC/ PLGA almost biodegraded at 24 weeks in the experimental group. The CPC degradation was much slower in the control group than in the experimental group. The total bone tissue percentage was 44.9% +/- 23.7% in the experimental group, and 25.7% +/- 10.9% in the control group, showing significant difference between 2 groups (t = 3.302, P = 0.001); and the bone tissue percentage showed significant difference between 2 groups at 8, 16, and 24 weeks (P < 0.05). The results of SEM observation showed that the pore size was 100-300 microm at 8 weeks after operation, new-born bone trabecula grew into the pores and combined strongly with residual cement in the experimental group. CONCLUSION: Novel CPC/PLGA has good in vivo degradable properties, and it can be an ideal bone substitute in future clinical application.