Delta like Non-Canonical Notch Ligand 2 inhibits chondrogenic differentiation and cell proliferation of bone marrow mesenchymal stem cells through the Notch1 signaling pathway.

Bone marrow mesenchymal stem cells (BMSCs) is the candidate for the treatment of cartilage defects because of their directional induction potential and natural anti-inflammatory properties. As one of the non-canonical receptors of Notch1, Delta Like Non-Canonical Notch Ligand 2 (DLK2) involves in stem cells' adipogenesis and chondrogenic differentiation. However, the specific regulatory mechanism of DLK2 in the chondrogenic differentiation of BMSCs is still unclear. In this study, we found that the expression of DLK2 was reduced and the expression of Col2a1, Col10a1, Acan, Sox9, and Notch1 was raised in the process of BMSCs chondrogenic differentiation. However, the expression of Col2a1, Col10a1, Acan, and Sox9 reduced significantly, and the signal factor Notch1 and the chondrogenic differentiation capacity of BMSCs turned down in the DLK2 overexpression group. Furthermore, the expression of Col2a1, Col10a1, Acan, and Sox9 significantly enhanced, Notch1 expression was also increased, and the chondrogenic differentiation capacity of BMSCs turned up in the DLK2 suppression group. Concurrently, the proliferation of BMSCs was weakened after overexpression of DLK2, and there was no significant change in cell migration. However, the proliferation and migration of BMSCs were significantly enhanced after the inhibition of DLK2 expression. Therefore, these results suggest that DLK2 negatively regulates chondrogenic differentiation and cell proliferation in BMSCs by inhibiting the Notch1 signaling pathway.

CircSFMBT2-OA alleviates chondrocyte apoptosis and extracellular matrix degradation through repressing NF-κB/NLRP3 inflammasome activation.

Background: Intra-articular inflammation and cartilage degradation are the major pathological characteristics of osteoarthritis (OA). Mounting studies have revealed that circular RNAs (circRNAs) act as an important regulatory role in inflammatory diseases and are frequently dys-expressed in OA cartilage tissues. Objective: Here, a dys-regulated cicrRNA (has_circ_0017636, termed circSFMBT2-OA) was identified, and its role in regulating lipopolysaccharide (LPS)-induced chondrocyte injury was next investigated. Methods: CHON-001 chondrocytes were treated with LPS, and then the levels of circSFMBT2-OA, cartilage-related genes, and pro-inflammatory cytokines were measured using quantitative real-time PCR (qRT-PCR) and Western blot analysis. CHON-001 cell viability, proliferation, and apoptosis were assayed using Cell Counting Kit-8 (CCK-8), 5-Ethynyl-2'-deoxyuridine (EDU), and terminal deoxynucleotidyl transferase (TdT) dUTP nick-end labeling (TUNEL) assay, respectively. Results: CircSFMBT2-OA level was significantly down-regulated in OA cartilage tissues and LPS-treated CHON-001 cells. Functionally, circSFMBT2-OA overexpression accelerated cell proliferation, and suppressed cell apoptosis, pro-inflammatory cytokines production, matrix-degrading enzymes expression, and ECM degradation in CHON-001 cells. Inversely, circSFMBT2-OA depletion decreased cell viability and increased matrix-degrading enzymes expression and ECM degradation. Mechanistically, circSFMBT2-OA inhibited LPS-induced NF-κB/NOD-like receptor family pyrin domain containing protein 3 (NLRP3) inflammasome activation in CHON-001 cells. Consequently, NLRP3 activator reversed the effect of circSFMBT2-OA on repressing LPS-induced CHON-001 cell injury. Conclusion: These data reveal a vital effect of a novel circSFMBT2-OA on repressing OA progression and provide a promising target to treat OA.

Comparison of accuracy for hip-knee-ankle (HKA) angle by X-ray and knee motion analysis system and the relationships between HKA and gait posture.

BACKGROUND: The lower limb mechanical axis was used to assess the severity of knee osteoarthritis (KOA) with varus/valgus deformity and the accuracy of targeted lower limb alignment correction after operation by conventional X-rays. There are lots of parameters to assess the gait in elder patients such as velocity, stride length, step width and swing/stance ratio by knee joint movement analysis system. However, the correlation between the lower limb mechanical axis and gait parameters is not clear. This study is aimed at obtaining the accuracy of the lower limb mechanical axis by the knee joint movement analysis system and the correlation between the lower limb mechanical axis and gait parameters. METHODS: We analysed 3D knee kinematics during ground gait of 99 patients with KOA and 80 patients 6 months after the operations with the vivo infrared navigation 3D portable knee joint movement analysis system (Opti-Knee®, Innomotion Inc, Shanghai, China). The HKA (Hip-Knee-Ankle) value was calculated and compared to X-ray findings. RESULTS: HKA absolute variation after the operation was 0.83 ± 3.76°, which is lower than that before the operation (5.41 ± 6.20°, p = 0.001) and also lower than the entire cohort (3.36 ± 5.72). Throughout the cohort, a significant correlation with low coefficients (r = -0.19, p = 0.01) between HKA value and anterior-posterior displacement was found. In comparing the HKA values measured on the full-length alignment radiographs and 3D knee joint movement analysis system (Opti-Knee), there was a significant correlation with moderate to high coefficients (r = 0.784 to 0.976). The linear correlation analysis showed that there was a significant correlation between the values of HKA measured by X-ray and movement analysis system (R2 = 0.90, p < 0.01). CONCLUSIONS: Data with equivalent results as HKA, the 6DOF of the knee and ground gait data could be provided by infrared navigation based 3D portable knee joint movement analysis system comparing with the conventional X-rays. There is no significant effect of HKA on the kinematics of the partial knee joint.

Regulation of Chondrocyte Differentiation by miR-455-3p Secreted by Bone Marrow Stem Cells through Phosphatase and Tensin Homolog Deleted on Chromosome Ten/Phosphoinositide 3-Kinase-Protein Kinase B.

The effects of the regulation of phosphatase and tensin homolog deleted on chromosome ten (PTEN) by microribonucleic acid- (miR-) 455-3p on bone marrow stem cells' (BMSCs') chondrogenic development were examined based on the phosphoinositide 3-kinase (PI3K)/protein kinase B (AKT) signal pathway. The alterations in miR-455-3p and PTEN were identified using osteoarthritis (OA) and healthy chondrocytes. Rats raised on the SD diet had their BMSCs isolated for chondrocyte-induced differentiation (blank group), transfected miR-455-3p mimic (mimic group), and inhibitor (inhibitor group). Besides, cell proliferation, alizarin red mineralization staining, and the activity of alkaline phosphatase (ALP) were detected. Real-time fluorescent quantitation polymerase chain reaction (PCR) and Western blot were utilized to detect Runx2, OPN, OSX, COL2A1 mRNA, and the difference between PI3K and AKT. Dual-luciferase reporter (DLR) genes were selected to analyze the target relationship of miR-455-3p to PTEN. It was demonstrated that miR-455-3p in OA was downregulated, while PTEN was upregulated (P < 0.05) in comparison to healthy chondrocytes (P < 0.05). Versus those in the blank group, alizarin red mineralization staining and the activity of ALP increased; RUNX, OPN, OSX, COL2A1 mRNA, p-PI3K, and p-AKT were elevated in the mimic group (P < 0.05). Versus those in the blank and mimic groups, alizarin red mineralization staining and the activity of ALP reduced; RUNX, OPN, OSX, COL2A1 mRNA, p-PI3K, and p-AKT were downregulated in the inhibitor group (P < 0.05). miR-455-3p could target PTEN to inhibit its expression, thus activating the PI3K/AKT signal pathway and promoting BMSCs chondrocyte-induced differentiation. The research results provided reference for the occurrence of OA and the study on therapeutic target.

[Effectiveness of intraoperative tibia fibular angle and femoral fibular angle in predicting coronal lower limb alignment after medial open-wedge high tibial osteotomy].

OBJECTIVE: To explore the prediction of postoperative coronal lower limb alignment by the tibia fibular angle (TFA) and femoral fibular angle (FFA) after osteotomy in medial open-wedge high tibial osteotomy (MOWHTO). METHODS: A clinical data of 20 patients with medial compartment osteoarthritis, who were treated with MOWHTO between September 2019 and September 2020, was retrospectively analyzed. Among them, there were 9 males and 11 females; the age ranged from 46 to 69 years, with an average of 56.0 years. The body mass index (BMI) was 21.3- 35.7 kg/m 2, with an average of 26.7 kg/m 2. Osteoarthritis involved 11 cases of left knee and 9 cases of right knee; the disease duration was 2-6 years, with an average of 3.8 years. According to the Kellgren-Lawrence classification, there were 7 cases of grade Ⅰ, 9 cases of grade Ⅱ, and 4 cases of grade Ⅲ. The angle and height for open-wedge was planned preoperatively by osteotomy master software, and the TFA and FFA were measured by software after simulated osteotomy. The intraoperative angle for open-wedge was adjusted according to TFA and FFA after simulated osteotomy.The lateral distal femoral angle (LDFA), medial proximal tibial angle (MPTA), joint line convergence angle (JLCA), mechanical femorotibial angle (mFTA), weight-bearing line (WBL) ratio, TFA, and FFA were measured before operation and at 2 days after operation. The difference (X) between the intraoperative measurement value and the preoperative plan value of TFA/FFA, and the difference (Y) between the postoperative WBL ratio and the target alignment (62.5%) were calculated, and the correlation between the two indicators was analyzed by Pearson's test. According to the median BMI of patients (25.81 kg/m 2), the patients were allocated into high BMI group (>25.81 kg/m 2, n=10) and low BMI group (≤25.81 kg/m 2, n=10), and the influencing factors of WBL ratio was analyzed by linear regression. RESULTS: There was no significant difference between pre- and post-operation in LDFA and JLCA ( P>0.05); while there were significant differences between pre- and post-operation in MPTA, mFTA, and WBL ratio ( P<0.05). The TFA was (89.5±4.0)° during operation and (87.7±4.7)° after operation, showing significant difference ( t=2.991, P=0.008). There was a positive correlation between the difference (X) between the intraoperative measurement value and the preoperative plan value of TFA and the difference (Y) between the postoperative WBL ratio and the target alignment ( r=0.595, P=0.006). The FFA was (86.9±4.3)° during operation and (85.7±4.4)° after operation, showing significant difference ( t=1.760， P=0.094). There was a positive correlation between the difference (X) between the intraoperative measurement value and the preoperative plan value of FFA and the difference (Y) between the postoperative WBL ratio and the target alignment ( r=0.536, P=0.015). After BMI stratification, X was an influential factor of Y in the low BMI group ( P<0.05), but X was not an influential factor of Y in the high BMI group ( P>0.05). CONCLUSION: Intraoperative FFA and TFA can predict coronal limb alignment after MOWHTO. FFA and TFA can predict more preciselyfor patients with BMI≤25.81 kg/m 2.

High-risk factors for subjective discomfort due to lower limb discrepancy after medial open wedge high tibial osteotomy.

BACKGROUND: Medial open wedge high tibial osteotomy (OWHTO) may result in lower limb discrepancy (LLD), and some patients experience uncomfortable symptoms. Studies have found that the degree of LLD is one but not the only high-risk factor for inducing symptoms. The main purpose of this study is to explore the risk factors for symptomatic LLD. METHODS: Sixty-four patients who underwent OWHTO in our hospital between June 2018 and January 2020 were included in the study. Changes in tibia length, lower limb length, femorotibial angle (FTA), LLD, and KOOS score were evaluated before and 1 year after surgery. Questionnaire was used to investigate whether patients had uncomfortable symptoms of LLD after surgery. Binary logistic regression was applied to analyze the risk factors of symptomatic LLD. RESULTS: There were 18 patients with subjective LLD uncomfortableness, 13 of them were occasional and 5 were frequent. Patients had a mean correction angle of 11.7° ± 4.6°, with a mean increase in tibial length of 6.0 ± 3.5 mm, lower limb length of 7.5 ± 2.3 mm, and LLD of 6.9 ± 4.2 mm at 1 year post-operation. Preoperative and postoperative changes in tibia length and lower limb length were statistically significant (P < 0.0001).There were statistically significant differences in pain, symptoms, ADL, sports/recreations, QOL of KOOS subclassification before and after surgery (P < 0.0001). Binary logistic regression revealed that age ≥ 55, BMI ≥ 28, and LLD ≥ 10 mm were high-risk factors for symptomatic LLD (P = 0.031, OR = 4.82; P = 0.012, OR = 6.251; P = 0.006, OR = 6.836). CONCLUSION: Patients with age ≥ 55, BMI ≥ 28, and postoperative LLD ≥ 10 mm are more likely to develop symptomatic LLD. Older or heavier patients, who are expected to have an LLD greater than 10 mm after OWHTO should be fully informed of the possibility of postoperative LLD symptoms.

Preoperative planning by osteotomy master software helps to improve the accuracy of target limb alignment in high tibial osteotomy.

BACKGROUND: The accuracy of targeted lower limb alignment correction following HTO is closely related to patients' pain relief and knee joint survival time. How to accurately perform osteotomy and how to obtain the ideal target limb alignment to maximize the curative effect are the difficulty in HTO practice. The purpose of this study is to evaluate the predictive and application value of osteotomy master software (OsteoMaster) in coronal plane preoperative planning of high tibial osteotomy. METHOD: Sixty-seven patients with medial compartment osteoarthritis and varus deformity treated by medial open-weight high tibial osteotomy were enrolled and divided into observation group (31 cases) and control group (36 cases). The observation group was planned by OsteoMaster, while the control group was planned by Miniaci. The preoperative predicted values of osteotomy depth, open height, correction angle, WBL ratio, and FTA of the observation group were compared with the actual intraoperative values to study their accuracy. The operative time, blood loss, number of fluoroscopy, and WBL ratio were compared between the observation group and the control group to study its application value. RESULT: There was no significant difference between two groups in preoperative prediction and intraoperative reality of osteotomy depth, open height, correction angle, FTA, and WBL ratio (P > 0.05). The operation time and number of fluoroscopy in the observation group were significantly less than those in the control group (P < 0.05), while the difference in blood loss was not statistically significant (P > 0.05). The good rate of WBL ratio was 87.1% in the observation group and 75% in the control group. CONCLUSION: OsteoMaster has predictive value in osteotomy depth, open height, correction angle, FTA, and WBL ratio of HTO, which is also helpful to reduce the number of fluoroscopy, shorten the operation time, and improve the accuracy of target limb alignment. The drawback of this approach is 2-dimensional approach in contrast to 3-dimensional preoperative planning that is including the more real study.

Incorporation of molybdenum disulfide into polyetheretherketone creating biocomposites with improved mechanical, tribological performances and cytocompatibility for artificial joints applications.

To improve mechanical, tribological and biological performances of polyetheretherketone (PEEK) for artificial joints applications, molybdenum disulfide (MoS2, MS) nanosheets were incorporated into PEEK to fabricate MS/PEEK biocomposites (MPC) with MS content of 4 w% (MPC4) and 8 w% (MPC8). The results revealed that the MS nanosheets with the size of about 400 nm and sheet thickness of about 70 nm were distributed into PEEK matrix, and surface roughness as well as hydrophilicity of MPC increased with the MS content increasing. Moreover, the compressive strength and shore hardness of the MPC were accordingly enhanced. Furthermore, the coefficient of friction of the MPC decreased while the wear resistance of the MPC increased with the MS content increasing in both water-sliding and dry-sliding contact. In addition, rat bone marrow derived stromal cells adhered and proliferated on the composites, indicating that the MPC had no adverse influences on cell behaviors, indicating good cytocompatibility. The results demonstrated that incorporation of MS nanosheets into PEEK produced biocomposites with improved mechanical, tribological and biological performances. MPC8 with no cytotoxicity would have a great potential for artificial joints applications.

Influences of sodium tantalite submicro-particles in polyetheretherketone based composites on behaviors of rBMSCs/HGE-1 cells for dental application.

Dental implanted materials require excellent mechanical properties, biocompatibility as well as integration with bone tissue and gingival tissue to achieve early loading and long-term stability. In this study, cubic shape sodium tantalite (ST) submicro-particles with the size of around 180 nm were synthesized by a hydrothermal method, and ST/polyetheretherketone (PEEK) composites (TPC) with ST content of 20 w% (TPC20) and 40 w% (TPC40) were prepared by melting blend. The results showed that the compressive strength, thermal properties, surface roughness, hydrophilicity and surface energy as well as adsorption of proteins on TPC40 were also significantly enhanced compared with TPC20 and PEEK. Moreover, the responses (adhesion and proliferation as well as differentiation) of rat bone marrow mesenchymal stem cells (rBMSCs), and responses (adhesion, and proliferation) of human gingival epithelial (HGE-1) cells to TPC40 were significantly promoted compared with TPC20 and PEEK. The results demonstrated that ST content in TPC had remarkable effects on the surface properties, which played key roles in stimulating the responses of both rBMSCs and HGE-1 cells. TPC40 with increased surface properties and excellent cytocompatibility might have great potential as an implanted material for dental application.

Highly dispersed lithium doped mesoporous silica nanospheres regulating adhesion, proliferation, morphology, ALP activity and osteogenesis related gene expressions of BMSCs.

Lithium (Li) doped mesoporous silica nanospheres (LMSNs) were synthesized by incorporation of 5 wt% Li into mesoporous silica nanospheres (MSNs) using sol-gel method. The results showed that LMSNs with a mean size of approximate 300 nm exhibited uniform and highly dispersed spherical morphology, which was similar to the morphology of MSNs. Moreover, the degradability of MSNs was significantly increased after the incorporation of Li, and LMSNs could release both silicon (Si) and Li ions in a sustained manner. Due to the release of Li ions, LMSNs showed higher stimulatory effects on the attachment and proliferation of bone marrow mesenchymal stem cells (BMSCs) than MSNs. In addition, LMSNs could also enhance the ALP activity of BMSCs as well as improving osteogenesis related genes (OPN, ALP, Runx2 and OCN) expression of BMSCs. In summary, LMSNs have shown the capability of being a carrier of biologically active ions, which exhibit great potential in bone repair/regeneration applications.

Comparison between cervical disc arthroplasty and conservative treatment for patients with single level cervical radiculopathy at C5/6.

BACKGROUND: Cervical radiculopathy is a common disease that affects millions of people. Patients usually are managed by conservative therapy and surgical treatments. OBJECTIVE: To compare the clinical outcomes between cervical disc arthroplasty (CDA) and conservative management for patients with single level cervical radiculopathy at C5/6. METHODS: Seventy-two patients with cervical radiculopathy that only affect C5/6 joints were included and thirty-two of them received CDA surgery, and forty patients were treated with conservative management. All the patients were followed up around 4 years. Cervical curvature, cervical range of motion (CROM), horizontal displacement of cervical spine, and intervertebral gap were measured by radiological examination. RESULTS: All the patients have comparable disease severity based on pre-surgical radiological assessments. At the 4-year follow-up examination, patients with CDA surgery had less CROM at C5/6 level, while greater CROM at C4/5 level, than control group. Similarly, the horizontal displacement in CDA group decreased at C5/6 vertebrae, and increased at C4/5 level at the 4-year follow-up examination. The intervertebral gaps of patients in CDA group were larger than control group at one-year and last follow-up examination. CONCLUSION: CDA surgery stabilized C5/6 vertebrae and increased the CROM and horizontal displacement of upper adjacent C4/5 vertebrae.

LAPONITE® nanorods regulating degradability, acidic-alkaline microenvironment, apatite mineralization and MC3T3-E1 cells responses to poly(butylene succinate) based bio-nanocomposite scaffolds.

Novel bio-nanocomposite scaffolds for bone tissue engineering were prepared by incorporation of LAPONITE® (LAP) nanorods into poly(butylene succinate) (PBSu). The results showed that the scaffolds had well interconnected macroporous structures with macropore size in the range of 200-400 µm and porosity of around 70%. In addition, the water absorption, degradability and apatite mineralization ability of the scaffolds were clearly enhanced with the increase of LAP content. Moreover, the degradation of LAP produced alkaline products, which neutralized the acidic degradable products of PBSu, and formed a weak alkaline microenvironment similar to a biological environment. Furthermore, the adhesion, proliferation and differentiation of MC3T3-E1 cells onto the scaffolds were significantly promoted with the increase of LAP content, in which the scaffold with 30 wt% LAP (sPL30) exhibited the best stimulation effect on the cells responses. The results suggested that the promotion of cells responses could be ascribed to the improvements of surface characteristics (including roughness, hydrophilicity, ions release and apatite formation, etc.) of the scaffolds. The sPL30 scaffold with excellent biocompatibility, bioactivity and degradability had great potential for applications in bone tissue engineering.

One-stage surgical treatment of cervical spine fracture-dislocation in patients with ankylosing spondylitis via the combined anterior-posterior approach.

The aim of the article is to investigate the efficacy and safety of 1-stage surgical therapy via combined anterior-posterior approach on cervical spine fracture in patients with ankylosing spondylitis (AS).We retrospectively analyzed profiles of 12 AS patients with severe fracture-dislocation of cervical spine received 1-stage combined anterior-posterior surgery in our hospital from October, 2013, to October, 2015, including clinical characteristics, follow-up data, and imaging records. We compared the parameters before and after surgery on the basis of neurological function, bone fusion, Cobb angles of operation segment, Barthel index (BI) score, and incidence rate of complications.A total of 12 patients received 1-stage surgery via combined anterior-posterior approach within 3 days after injury. No severe complications and death occurred. All patients received the successfully anatomical reduction of fracture-dislocation, in which 9 achieved function restoration. The latest follow-up showed the neurological function status of patients was improved. The Cobb angles of operation segments were recovered; the rate of bone fusion was 66.7% at 3 months and 100% at 6 months post-operation. The BI score was improved, 4 cases of moderate dependence and 8 of slight dependence at the latest follow-up compared to 10 of severe dependence and 2 of moderate dependence preoperation. In no cases did severe complications from implanted instrumentation occur.It was high efficacy and safety that the surgical therapy was performed on cervical fracture-dislocation in AS patients by the 1-stage combined anterior-posterior approach. The key of the surgery is the robust stabilization and full decompression of fracture spine at early stage. In addition, if spinal anatomical reduction of fracture segments is difficult to be achieved, the functional restoration should be adopted during the surgery.