Zhikun Li

Derivation of male germ cells from induced pluripotent stem cells in vitro and in reconstituted seminiferous tubules.

Previous studies have demonstrated that mouse‐ and human‐induced pluripotent stem (iPS) cells can differentiate into primordial germ cells in vitro. However, up to now it is not known whether iPS cells would be able to differentiate into male germ cells in vivo. The aim of this study was to explore differentiation potential of iPS cells to male germ cells in vitro and in vivo.

Knockdown of HuR represses osteosarcoma cells migration, invasion and stemness through inhibition of YAP activation and increases susceptibility to chemotherapeutic agents

This study aims to explore the roles and related mechanisms of HuR in osteosarcoma (OS) cells migration, invasion, stemness and chemotherapeutical sensitivity. Here, we found that HuR exhibited higher level in OS tissues compared with the adjacent normal tissues. Knockdown of HuR with lentivirus infection suppressed OS cells migration and invasion, and thus the epithelial-mesenchymal transition (EMT) process. Additionally, HuR knockdown inhibited OS cells stemness. Mechanistically, YAP was identified as a direct target of HuR in OS cells, and HuR knockdown decreased its expression. Moreover, YAP transcriptional activity was attenuated by HuR knockdown, and RNA immunization co-precipitation (RIP) assay showed that HuR directly bound with YAP. Importantly, YAP overexpression rescued the inhibition of HuR knockdown on OS cells migration, invasion and stemness. Furthermore, HuR knockdown enhanced adriamycin sensitivity in OS cells, this effect was attenuated by YAP overexpression too. Importantly, HuR and YAP expression was positively correlated in OS tissues. Therefore, HuR acts as a tumor promoter by enhancing YAP expression in OS cells.

Glycyrrhizin Suppresses RANKL-Induced Osteoclastogenesis and Oxidative Stress Through Inhibiting NF-κB and MAPK and Activating AMPK/Nrf2

The treatment for osteoporosis involves inhibiting bone resorption and osteoclastogenesis. Glycyrrhizin (GLY) is a triterpenoid saponin glycoside known to be as the most medically efficacious component of the licorice plant. It has strong anti-inflammatory, antioxidant, and antitumor properties. We investigated the effect of GLY on osteoclastogenesis, bone resorption, and intracellular oxidative stress and its molecular mechanisms. In vitro osteoclastogenesis assays were performed using bone marrow monocytes with and without glycyrrhizin. We also evaluated the effects of glycyrrhizin on the secretion of TNF-α, IL-1β, and IL-6 in LPS-stimulated RAW 264.7 cells using ELISA. The effects of glycyrrhizin on the expression of osteoclast-related genes, such as Nfatc1, c-fos, Trap, and cathepsin K (CK), were investigated by RT-PCR. Intracellular reactive oxygen species (ROS) were detected in receptor activator of nuclear factor kappa-Β ligand (RANKL)-stimulated osteoclasts in the presence and absence of glycyrrhizin. During the inhibition of osteoclastogenesis by glycyrrhizin, phosphorylation of AMPK, Nrf2, NF-κB, and MAPK was analyzed using western blotting. Our results showed that glycyrrhizin significantly inhibited RANKL-induced osteoclastogenesis, downregulated the expression of NFATc1, c-fos, TRAP, CK, DC-STAMP, and OSCAR, and inhibited p65, p38, and JNK. Glycyrrhizin was found to significantly decrease the secretion of inflammatory cytokines (TNF-α, IL-1β, and IL-6). Additionally, glycyrrhizin reduced the formation of ROS in osteoclasts by inducing AMPK phosphorylation and nuclear transfer of NRF2, resulting in an upregulation of antioxidant enzymes, such as HO-1, NQO-1, and GCLC. In summary, we found that glycyrrhizin inhibited RANKL-induced osteoclastogenesis. It was also indicated that glycyrrhizin could reduce oxidative stress by inhibiting the MAPK and NF-κB pathways and activating the AMPK/NRF2 signaling. Therefore, glycyrrhizin may be used as an effective therapeutic agent against osteoporosis and bone resorption.

Risk Factors for Dysphagia After Anterior Cervical Spine Surgery

This study evaluated the risk factors for dysphagia after anterior cervical spine surgery by multidimensional analysis and investigated the predictive values of these risk factors for dysphagia. The patients underwent anterior cervical spine surgery and were followed for at least 6 months. Sex, age, tracheal mobility, smoking history, implant type, C3 anterior vertebral soft tissue swelling, narrowest esophageal distance before internal fixation, cervical curvature, operative time, occurrence of fusion, number of operative segments, and highest vertebral segment were recorded. Chi-square test and logistic regression were performed to analyze the predictive value of each dimension for dysphagia. A total of 158 patients were included in this study. The mean C3 anterior vertebral soft tissue swelling was 8.8±4.5 mm, the mean narrowest esophageal distance before internal fixation was 6.9±4.4 mm, and the mean operative time was 78.5±39.2 minutes. Chi-square test results showed that age 60 years and older, female sex, internal fixation with titanium plate/titanium mesh, narrowest esophageal distance before internal fixation of less than 5 mm, and 3 operative segments indicated a relatively high incidence of dysphagia. Logistic regression analyses showed that age, sex, implant type, narrowest esophageal distance before internal fixation, and number of operative segments were all risk factors predictive of postoperative dysphagia. The area under the receiver operating characteristic curve was 0.872. Age 60 years and older, female sex, internal fixation with titanium plate/titanium mesh, narrowest esophageal distance before internal fixation of less than 5 mm, and 3 operative segments were risk factors for dysphagia after anterior cervical surgery. The regression equation may be used to predict the occurrence of dysphagia. [Orthopedics. 2018; 41(1):e110-e116.].

Distal adding-on phenomenon in adolescent idiopathic scoliosis patients with thoracolumbar vertebra fusion: A case–control study

Abstract The adding-on phenomenon is a common complication in adolescent idiopathic scoliosis (AIS) patients after correction surgery. However, the risk factors of previous studies and the optimal treatment strategies remain controversial. The aim of this study was to identify new risk factors for the adding-on phenomenon after posterior correction surgery in AIS patients and compare different treatment strategies to guide the selection of the lowest instrumented vertebra (LIV). All types of Lenke AIS patients who received correction surgery at our center from January 2009 to July 2014 were analyzed. The anteroposterior and lateral films were evaluated before surgery, at the 2-week follow-up, and at the 2-year or later follow-up. The patients were divided into 2 groups according to whether adding-on was observed at the last follow-up. The factors predictive of the adding-on phenomenon were identified in a multivariate binary logistic regression model. Different methods for LIV selection were compared in both the adding-on group and the control group (no adding-on). Out of the 346 patients reviewed, 92 met the inclusion criteria; 22 of these met the definition for distal adding-on, and were included in adding-on group. The remaining 70 patients were included in the no adding-on group. The average follow-up was 3.6 years. Touch classification (P < .000), Dnfs (P = .005), and vertebra number between LIV and angle velocity (AV) (P = .001) were significantly different between the 2 groups. Age, gender, Risser sign, and screw density were not found to be affiliated with the presence of adding-on. The results of the Scoliosis Research Society (SRS)-22 were not significantly different between the adding-on group and the control group for any section or overall (P > .05). Binary logistic regression results indicated that postoperative LAV deviation from the CSVL and Touch classification were independent predictive factors. Among the 4 methods, only choosing touch type A as LIV shows satisfactory outcome. The Touch classification is an important risk factor that is highly correlated with the incidence of the adding-on phenomenon. The best LIV choice to preserve the lumbar activity segment as much as possible is Touch type C, and no significant difference was observed in the SRS-22 scores between the Touch type C group and the control group in the short-term follow-up.

LncRNA B4GALT1-AS1 recruits HuR to promote osteosarcoma cells stemness and migration via enhancing YAP transcriptional activity

This study aims to reveal the roles and related mechanisms of LncRNA B4GALT1‐AS1 in osteosarcoma (OS) cells stemness and migration.

The radiographic parameter risk factors of rapid curve progression in Lenke 5 and 6 adolescent idiopathic scoliosis: A retrospective study

Abstract Various parameters related to growth and maturity have been shown to be risk factors for scoliosis curve progression. We previously identified correlations between curve progression and radiographic parameters in clinical practice, but there is a lack of research. The aim of this study was to investigate and identify the radiographic parameters that are risk factors for rapid curve progression in Lenke 5 or 6 adolescent idiopathic scoliosis (AIS). A retrospective review of patients who were prospectively enrolled at the initiation of brace wear and followed through completion of bracing or surgery was performed. The inclusion criteria were as follows: a Lenke type 5 or 6 classification, Risser sign grade 0 or 1 at the initial outpatient examination, a follow-up period of 6 months including a minimum of 4 follow-ups, At each visit, the whole spine x-ray was completed, the following data were measured and collected: angle of the lumbar curve (LC), rotation of the apical vertebra (RAV) in the LC, deviation of the apical vertebra (DAV) in the lumbar curve, clavicle angle, L5 tilt angle (TA), body mass index, flexibility of the LC (FLC), and peak angle velocity (PAV). A binary logistic regression analysis was used to assess the contribution of each variable to PAV onset. The touch types for the determination of the lowest instrumented vertebra (LIV) were compared at both the PAV and final follow-up. Thirty-six AIS patients were recruited. The binary logistic regression model indicated that the following variable values significantly contributed to a high risk of PAV occurrence: LC ≥30° (OR = 6.153, 95%CI = 1.683–22.488, P = .006), RAV ≥III (OR = 15.484, 95%CI = 4.535–52.865, P <.001), DAV ≥40 mm (OR = 8.599, 95%CI = 2.483–29.784, P <.001), and TA ≥10° (OR = 2.223, 95%CI = 3.094–27.563, P <.001). The touch types for LIV determination changed in 12 of 36 patients, with at least 1 segment added as the LIV between the PAV and the final visit. LC ≥30°, RAV ≥III, DAV ≥40 mm, and L5 TA≥10° were radiographic parameters associated with an increased risk of curve progression in Lenke 5 and 6 AIS. The orthopedic surgery performed at the PAV is the ideal timing, and it will preserve 1 active segment than later surgery. Level of evidence was 4.

Revision surgery after pregnancy in a patient with congenital kyphoscoliosis: A case report

Rationale: Rod breakage during pregnancy and delivery has never been described in a patient who has undergone surgery for congenital scoliosis (CS). Here, we present an unusual but significant case of revision surgery. Patient concerns: A 29-year-old woman presented with low back pain during pregnancy after posterior osteotomy, correction and fusion at T9 to L5 for CS. Radiographs during follow-up, 4 months after the patient gave birth, demonstrated rod breakage. Diagnoses: Rod breakage after orthopaedic surgery of congenital kyphoscoliosis Interventions: The patient was taken into the operating room for replacement of the broken rods, recovery of sagittal balance, bone graft fusion, and improvement of stability by cross-connection. The patient recovered fully by the 3-month postoperative follow-up. Outcomes: In follow-up, the instruments were in good condition, the orthopedic effect was not lost, and low back pain relief was observed. Lessons: We opine that the rod breakage during pregnancy resulted from weight gain and a lack of an anterior approach to the supportive bone graft. Therefore, female patients with spinal surgery should visit the hospital for advice before pregnancy.