Black phosphorus, an advanced versatile nanoparticles of antitumor, antibacterial and bone regeneration for OS therapy.

Osteosarcoma (OS) is the most common primary malignant bone tumor. In the clinic, usual strategies for OS treatment include surgery, chemotherapy, and radiation. However, all of these therapies have complications that cannot be ignored. Therefore, the search for better OS treatments is urgent. Black phosphorus (BP), a rising star of 2D inorganic nanoparticles, has shown excellent results in OS therapy due to its outstanding photothermal, photodynamic, biodegradable and biocompatible properties. This review aims to present current advances in the use of BP nanoparticles in OS therapy, including the synthesis of BP nanoparticles, properties of BP nanoparticles, types of BP nanoparticles, and modification strategies for BP nanoparticles. In addition, we have discussed comprehensively the application of BP in OS therapy, including single, dual, and multimodal synergistic OS therapies, as well as studies about bone regeneration and antibacterial properties. Finally, we have summarized the conclusions, limitations and perspectives of BP nanoparticles for OS therapy.

Finite element analysis of the effect of tibial osteotomy on the stress of polyethylene liner in total knee arthroplasty.

AIM: To explore the effects of tibial osteotomy varus angle combined with posterior tibial slope (PTS) on the stress of polyethylene liner in total knee arthroplasty (TKA) by building finite element model (FEM). METHODS: Established the FEM of standard TKA with tibial osteotomy varus angle 0° to 9° were established and divided into 10 groups. Next, each group was created 10 FEMs with 0° to 9° PTS separately. Calculated the stress on polyethylene liner in each group in Abaqus. Finally, the relevancy between tibial osteotomy angle and polyethylene liner stress was statistically analyzed using multiple regression analysis. RESULTS: As the varus angle increased, the area of maximum stress gradually shifted medially on the polyethylene liner. As the PTS increases, the percentage of surface contact forces on the medial and lateral compartmental of the polyethylene liner gradually converge to the same. When the varus angle is between 0° and 3°, the maximum stress of the medial compartmental surfaces of polyethylene liner rises smoothly with the increase of the PTS. When the varus angle is between 4° and 9°, as the increase of the PTS, the maximum stress of polyethylene liner rises first and then falls, forming a trough at PTS 5° and then rises again. Compared to the PTS, the varus angle has a large effect on the maximum stress of the polyethylene liner (p < .001). CONCLUSION: When the varus angle is 0° to 3°, PTS 0° is recommended, which will result in a more equalized stress distribution of the polyethylene liner in TKA.

Collagen-Based Hydrogels for Cartilage Regeneration.

Cartilage regeneration remains difficult due to a lack of blood vessels. Degradation of the extracellular matrix (ECM) causes cartilage defects, and the ECM provides the natural environment and nutrition for cartilage regeneration. Until now, collagen hydrogels are considered to be excellent material for cartilage regeneration due to the similar structure to ECM and good biocompatibility. However, collagen hydrogels also have several drawbacks, such as low mechanical strength, limited ability to induce stem cell differentiation, and rapid degradation. Thus, there is a demanding need to optimize collagen hydrogels for cartilage regeneration. In this review, we will first briefly introduce the structure of articular cartilage and cartilage defect classification and collagen, then provide an overview of the progress made in research on collagen hydrogels with chondrocytes or stem cells, comprehensively expound the research progress and clinical applications of collagen-based hydrogels that integrate inorganic or organic materials, and finally present challenges for further clinical translation.

POLR2A blocks osteoclastic bone resorption and protects against osteoporosis by interacting with CREB1.

Bone-resorbing osteoclasts significantly contribute to osteoporosis, and understanding the mechanisms of osteoclastogenesis is crucial for developing new drugs to treat diseases associated with bone loss. Here, we report that POLR2A is upregulated during osteoclastogenesis. Functional analyses showed that the inhibition of POLR2A decreased osteoclastogenesis, whereas the overexpression of POLR2A had completely opposite effects in vitro. Notably, the osteoclast-specific deletion of POLR2A blocks bone resorption in vivo. Furthermore, POLR2A loss-of-function suppresses estrogen deficiency-induced bone resorption. Mechanistically, POLR2A regulates the assembly of CREB1 on the regulatory elements of its target genes. Collectively, using genetic, pharmacological, and disease mouse models, we have identified a previously undescribed protein that interacts with CREB1 to regulate osteoclastic bone resorption.

Study on the effect of extra capsular arthroscopy plus analgesic tincture in the treatment of external humeral epicondylitis.

External humeral epicondylitis (EHE) is an inflammation and pain of the lateral tendons of the elbow with poor clinical efficacy. In this study, we aim to observe the effect of extra capsular arthroscopy (ECA) plus Traditional Chinese medicine (TCM) analgesic tincture in the treatment of EHE. A retrospective analysis was performed on the follow-up data of 58 patients with intractable EHE treated by ECA plus TCM analgesic tincture over 2 years from January 2017 to October 2018. All patients were followed up during the operation, with a mean follow-up duration of 17.6 months. There were no complications such as infection, nerve injury, wound nonunion and joint stiffness. The postoperative and pronation angles were statistically different from preoperative. The visual analogue scale (VAS) score during rest and movement of the elbow joint after operation was significantly different from that before operation. Postoperative Mayo elbow joint function score was significantly different from preoperative. Postoperative elbow joint function and brachial and shoulder dysfunction scores were statistically significant compared with those before surgery. Postoperative elbow joint function and brachial and shoulder dysfunction scores were statistically significant compared with those before surgery. The satisfaction rate of patients was 100%, with 52 cases of completely satisfied, 6 cases of basically satisfied and no dissatisfied cases. The curative effect of external capsular arthroscopy plus analgesic tincture in the treatment of external humeral epicondylitis was promising, which was worthy of clinical promotion.

[Phase I total hip replacement for severe hip osteoarthritis with proximal femoral fractures].

OBJECTIVE: To investigate the effect and prognosis of stage I total hip replacement in the treatment of severe hip osteoarthritis with proximal femoral fracture. METHODS: From July 2014 to October 2017, 8 patients with severe end-stage hip disease and proximal femoral fracture were treated with stage I total hip replacement including 6 males and 2 females, aged 59 to 72 years old with an average age of 65 years old, involving 4 femoral head necrosis with proximal femoral fracture in the right side, 3 femoral head necrosis with proximal femoral fracture in the left side, and 1 left acetabular dysplasia with proximal femoral fracture in the left side. The average time from injury to operation was 7 days. Eight patients were treated with biologically elongated hip prosthesis. RESULTS: Eight patients with stage I total hip arthroplasty were followed up for 12 to 48 months with an average of 31 months. During the follow-up period, there was no loosening or subsidence of the prosthesis. Harris score increased from 33 points (22 to 42 points) preoperatively to 87 points(82 to 90 points) at the last follow-up. Among them, 3 cases were excellent and 5 cases were good. Abandoned abduction and walked 3 months after operation. X-ray films during 3-6 months after operation showed that fracture healing was good, hip pain and function were improved significantly, and the quality of life was greatly improved. CONCLUSIONS: Phase I total hip arthroplasty for severe hip osteoarthritis patients with proximal femoral fracture has the advantages of shortening the treatment time, alleviating patients'pain, reducing hospitalization costs and good prognosis.

MicroRNA-495 enhances chondrocyte apoptosis, senescence and promotes the progression of osteoarthritis by targeting AKT1.

Osteoarthritis (OA) is a common multifactorial degenerative articular disease among the aging population. The current investigation aimed to elucidate the function of microRNA-495 (miR-495) in the development of OA. We found that miR-495 was upregulated in the cartilage of OA patients. Transfection of a miR-495 mimic into rat primary chondrocytes, human chondrocytes (HC) and SW1353 chondrosarcoma cells inhibited AKT1 expression, proliferation and scratch wound closure and induced apoptosis. Transfection of a miR-495 inhibitor produced an opposite effect. Furthermore, the production of cartilage degeneration-related substances was modified by miR-495. Luciferase reporter gene assay revealed that AKT1 is directly repressed by miR-495. Moreover, the levels of AKT1, p-S6 and p-mTOR diminished in chondrocytes overexpressing miR-495. AKT1 overexpression amplified p-S6 and p-mTOR levels as well as abolished miR-495 mimic-induced apoptosis and inhibition of proliferation. In the surgically induced rat OA model, apoptosis of chondrocytes and cartilage degeneration were remedied by the administration of a miR-495 antagomir. Moreover, there was an increased expression of AKT1. These findings indicate that miR-495 induces OA by targeting AKT1 and regulating the AKT/mTOR pathway. Therefore, miR-495 may be a prospective target for OA treatment.

Long non-coding RNA GClnc1 promotes tumorigenesis in osteosarcoma by inhibiting p53 signaling.

Recent studies suggest important roles for long noncoding RNAs as essential regulators of human cancer. GClnc1 was found to be upregulated in gastric cancer, playing oncogenic roles. However, the biological function and underlying mechanism of GClnc1 in osteosarcoma (OS) remain unclear. Here, we report that GClnc1 is upregulated in OS tissues and its high expression predicts poor prognosis of patients. Functional analyses show that overexpression of GClnc1 promotes OS cells growth; whereas knockdown of GClnc1 has completely opposite effects. Consistently, overexpression of GClnc1 promotes tumorigenicity of OS cells in vivo. Mechanistically, GClnc1 directly binds to p53 and blocks the binding of p53 to acetyltransferase p300, and thereby suppresses acetylation of p53, leading to the reduced expression of p21 and BAX. This study shed light on the oncogene role of lncRNA GClnc1, a new modulator of p53 signaling, in OS.

The effect of PLGA-based hydrogel scaffold for improving the drug maximum-tolerated dose for in situ osteosarcoma treatment.

Although hydrogel-based therapeutic agents have shown great potential for localized cancer treatments, the maximum tolerated dose (MTD) of these methods remains uncertain. To confirm this, doxorubicin (DOX) loaded PLGA-PEG-PLGA hydrogel was employed to investigate the MTD of DOX for localized osteosarcoma treatment. This hydrogel showed good injectable and biodegradable properties in vivo. And the drug remaining time was also obviously prolonged in the tumor site. Different doses of DOX (5.0, 15, 30 mg/kg) with/without hydrogel were adopted to the treatment of tumor-bearing mice. Despite both localized administrations of 5.0 mg/kg DOX showing no obvious systemic toxicity, this dose failed to control the persistent growth of tumors or prolong the survival time in comparison with the control groups. Localized administration of 30 mg/kg DOX showed a high efficacy for suppressing tumor growth, but exhibited obvious body weight losing at the same time. Correspondingly, the DOX-loaded hydrogel with the dose of 15 mg/kg achieved significantly improved anti-tumor efficacy and prolonged mean survival time compared with both the free DOX (15 mg/kg) and other control groups. Furthermore, during the whole therapeutic process, the mice showed no obvious body weight loss, major organs damage or death in this group. The MTD of DOX-loaded agent based on the PLGA-PEG-PLGA hydrogel gave a 2-fold increase compared to the MTD of free DOX (7.5 mg/kg, intravenous injection) for the mouse without significant systemic toxicity.

TAZ overexpression is associated with epithelial-mesenchymal transition in cisplatin-resistant gastric cancer cells.

Gastric cancer is one of the common malignant diseases. The poor treatment outcome is mainly due to chemotherapeutic resistance. Therefore, it is important to determine the molecular mechanism of drug resistance in gastric cancer. To explore the mechanisms of cisplatin resistance in gastric cancer cells, several approaches were performed including MTT assay, real-time RT-PCR, western blot analysis, migration and invasion assays, wound healing assay, and transfection. We found that cisplatin-resistant (CR) gastric cancer cells acquired epithelial-mesenchymal transition (EMT) phenotype. The CR cells with EMT features obtained higher migratory and invasive activities. Moreover, we observed that TAZ was highly expressed in CR cells. Consistently, depletion of TAZ caused partial reversal of EMT to MET in CR cells. Our results suggest that TAZ plays a pivotal role in CR-induced EMT. Targeting TAZ could be a potential therapeutic strategy for gastric cancer.

[Repairing diabetic rats with bone defect by VEGF165 gene modified adipose-derived stem cells].

OBJECTIVE: To explore repairing results of VEGF165 gene modified adipose-derived stem cells for diabetic rats with bone defect. METHODS: Seventy-eight male Wistar rats weighted 180 to 220 g were selected, 72 rats were established diabetic animal models by streptozotocin inducement method, blood glucose level was more than 16.7 mmol/L. Experimental animals were randomly divided into 5 groups, 6 rats in normal group and each 18 rats in other groups. VEGF165 gene modified adipose-derived stem cells were implanted into normal group with bone defect; single diabetic rats with bone defect were named as diabetic group;vascular endothelial growth factor implanted into single diabetic rats with bone defect named as growth factor group; adipose-derived stem cells implanted into diabetic rats with bone defect names as stem cell group; VEGF165 gene modified adipose-derived stem cells implanted diabetic rats with bone defect named as experimental group. After combination of VEGF165-ADSCs (5×106) cells combined with gel sponge, implanted into diabetic rats with bone defect. On the forth week, general form of defect repairing tissue were observed by optical microscopy;local density of micro-vessel were detected by immunohistochemistry method; content of Ca, P and ALP of repairing callus were detected by IRIS Intrepid XSP inductively coupled plasma emission spectrometer. Efficacy of the VEGF165-ADSCs repairing function was evaluated by SPSS statistic software. RESULTS: Fluorescent staining results showed that expression of VEGF165 located on cytoplasm of ADSCs, expression percentage was more than 87%; general histology results showed that callus formation and quality was near to normal group, repairing results in diabetes group, growth factor group and stem cell group were poor. On the Forth week after implantation, content of Ca, P and ALP of repairing callus in experimental group were higher than those in growth group and stem cell group, and without significant differences compared with normal group; blood vessel density in experimental group was lower than normal group, but higher than other groups. CONCLUSIONS: VEGF165 gene modified adipose-derived stem cells for repairing diabetic rats with bone defect has advantages of osteogenesis and angiogenesis, and should be one of the effective method for repairing diabetic rats with bone defect.

Validation of suitable reference genes for quantitative polymerase chain reaction analysis in rabbit bone marrow mesenchymal stem cell differentiation.

Bone marrow mesenchymal stem cells (BMSCs) are considered as multipotent cells, representing a multi-lineage potential to differentiate into mesodermal lineages of mesenchymal tissues, including cartilage, bone, fat, muscle and tendon. Tissue engineering in BMSCs has made great advances in the regeneration of cartilage and bone defects. To uncover the mechanisms of the multipotent differentiation process, the molecular changes in gene expression profiles during chondrogenic and osteogenic differentiation need to be evaluated with reliable, accurate, fast and sensitive methods. Reverse transcription-quantitative polymerase chain reaction is a commonly used technology for analyzing gene expression, depending on an appropriate reference gene to normalize the errors. The commonly used reference genes vary, and no ideal and universal reference genes suitable for all conditions exist; therefore validation of the stability of gene expression is required. In the present study, three common statistical algorithms, geNorm, Normfinder and BestKeeper, were used to identify the expression stability of 12 genes, and the target differentiation markers during the differentiation of BMSCs were evaluated accurately. Our results demonstrated that YWHAZ, PPIA and GAPDH were suitable as reference genes for chondrogenic differentiation, while RPL13a allowed an efficient normalization expression value of interest genes for osteogenic differentiation of BMSCs. By contrast, the most unstable reference genes were 18s rRNA, B2M and HPRT1 in all studies, and these should be avoided when investigating the differentiation of BMSCs. Our results demonstrate validation of the appropriate reference genes for accurate gene expression in chondrogenic and osteogenic differentiation of BMSCs.

PLK1shRNA and doxorubicin co-loaded thermosensitive PLGA-PEG-PLGA hydrogels for osteosarcoma treatment.

Combination cancer therapy has emerged as crucial approach for achieving superior anti-cancer efficacy. In this study, we developed a strategy by localized co-delivery of PLK1shRNA/polylysine-modified polyethylenimine (PEI-Lys) complexes and doxorubicin (DOX) using biodegradable, thermosensitive PLGA-PEG-PLGA hydrogels for treatment of osteosarcoma. When incubated with osteosarcoma Saos-2 and MG-63 cells, the hydrogel containing PLK1shRNA/PEI-Lys and DOX displayed significant synergistic effects in promoting the apoptosis of osteosarcoma cells in vitro. After subcutaneous injection of the hydrogel containing PLK1shRNA/PEI-Lys and DOX beside the tumors of nude mice bearing osteosarcoma Saos-2 xenografts, the hydrogels exhibited superior antitumor efficacy in vivo compared to the hydrogels loaded with PLK1shRNA/PEI-Lys or DOX alone. It is noteworthy that the combination treatment in vivo led to almost complete suppression of tumor growth up to 16 days, significantly enhanced PLK1 silencing, higher apoptosis of tumor masses, as well as increased cell cycle regulation. Additionally, ex vivo histological analysis of major organs of the mice indicated that the localized treatments showed no obvious damage to the organs, suggesting lower systemic toxicity of the treatments. Therefore, the strategy of localized, sustained co-delivery of PLK1shRNA and DOX by using the biodegradable, injectable hydrogel may have potential for efficient clinical treatment of osteosarcoma.

The use of deep frozen and irradiated bone allografts in the reconstruction of tibial plateau fractures.

To investigate the clinical behavior of deep frozen and irradiated bone allografts in the treatment of depressed tibial plateau fractures. Twenty-two patients with a tibial plateau fracture were treated with cancellous bone allografts. The bone allograft preparation process included fresh-freezing at -70 °C for 4 weeks and gamma-irradiation at 25 kGy. All of the patients were followed for 1-2 years. The clinical effects were assessed using the Rasmussen score for tibial head fractures and X-rays. Postoperatively, the average excellent and fair Rasmussen scores were 88.9%. Only one patient developed an infection, with no integration between allograft and recipient bone observed. All of the other bone allografts were incorporated successfully, and no osteoporosis or sclerosis was observed. The frozen and gamma-irradiated bone allograft is a good alternative in the treatment of tibial plateau fractures, which we have shown can integrate with the surrounding host bone.

Biomechanical evaluation of various fixation methods for proximal extra-articular tibial fractures.

OBJECTIVE: Proximal tibial fractures are a challenging clinical problem. The treatment protocols for these fractures include a dynamic compression plate (DCP), a locking compression plate (LCP), interlocking intramedullary nailing (IMN), and external fixation (Ex-Fix). However, the optimal fixation method for proximal tibial fractures remains controversial. The purpose of this study was to investigate the biomechanical properties of these four fixation instruments in the treatment of tibial proximal fractures. METHODS: Thirty-two tibial specimens were retrieved and randomly divided into four groups. Extra-articular proximal tibial fractures (AO classification 41-A2) were created in each specimen. The fractures were subsequently fixed by DCP, LCP, IMN, and Ex-Fix. The bone density of the proximal tibiae was examined by quantitative computed tomography. Each specimen was subjected to axial compression and three-point bending tests. RESULTS: Bone mineral density did not significantly differ among the groups. In compression testing of the four fixation instruments, the highest degree of axial stiffness was found in the IMN group; there was no significant difference between DCP and LCP groups (P>0.05). The results of the three-point bending test revealed that DCP demonstrated the highest bending stiffness, which differed significantly from the other groups (P<0.05). The Ex-Fix had the lowest level of stiffness during the compression and three-point bending tests. CONCLUSIONS: IMN has good mechanical properties, but its clinical application for proximal tibial fractures often leads to malalignment deformities. Compared with DCP, LCP is strong enough to fix the proximal tibial fractures and has the additional benefit of minimally invasive surgery.

[Treatment of humeral supracondylar fracture in children with neurovascular complications].

OBJECTIVE: To discuss the treatment methods of humeral supracondylar fracture in children with neurovascular complications. METHODS: Ninety-six children (59 males, 37 females) with humeral supracondylar fractures were treated by surgery from February 2002 to November 2007, with the mean age of 6.4 years old (ranged from 4 to 16 years). Seventeen symptoms of nerve damage occurred in 16 cases, including radial nerve injury in 5 cases,median nerve injury in 7 cases,of which 1 cases with ulnar nerve injury, ulnar nerve injury in 5 cases; 13 patients had symptoms of vascular injury such as pulse weakness and hands coldness. The patients accompanied by nerve, blood vessel injury symptoms were all treated with open reduction and internal fixation. RESULTS: Eighty-five patients were followed up with an average duration of 11 months(ranged from 6 to 18 months). Seventy-three patients had incision healing at the first stage and other 12 patients had incision healing at the second stage. All the 85 patients had no complications such as incision infection and functional disturbance of elbow joint. Among 5 patients with radial nerve injury, 3 patients had symptoms disappeared completely at 3 months after operation; one patient underwent exploration lysis at 3 months after operation and the symptoms disappeared at 5 months after operation; another 1 patient with iatrogenic injury of radial nerve had nerve function recovered at 3 months after releasing plaster compression. Among 7 patients with median nerve injury, 6 patients had nerve function recovered completely at 6 months after operation; another 1 patient combined with ulnar nerve injuries had nerve function recovered at 9 months after exploring of nerve at the second stage. Five patients with ulnar nerve injury had nerve function recovered completely at 6 months after operation. Preoperative symptoms of radial artery pulse weakness and cold hand in 13 patients disappeared after fracture reduction. CONCLUSION: The ulnar nerve should be explored during the operation at the first stage of supracondylar fracture. Wether the median nerve, radial nerve and blood vessel be explored or not should be decided by preoperative examination results. The preoperative EMG and Doppler ultrasound examination is not a routine examination before surgery.