Prognostic nomogram in middle-aged and elderly patients with chordoma: A SEER-based study.

BACKGROUND: Chordoma is a bone tumor that tends to occur in middle-aged and elderly people. It grows relatively slowly but is aggressive. The prognosis of middle-aged and elderly patients with chordoma is quite different from that of young patients with chordoma. OBJECTIVES: The purpose of the research was to construct a nomogram to predict the Individualized prognosis of middle-aged and elderly (age greater than or equal to 40 years) patients with chordoma. METHODS: In this study, we screened 658 patients diagnosed with chordoma from 1983 to 2015 in the Surveillance, Epidemiology, and End Results (SEER) database. We determined the independently prognostic factors that affect the survival of patients by univariate and multivariate Cox proportional hazards model. Based on the independent prognostic factors, we constructed a nomogram to predict the overall survival (OS) rates of middle-aged and elderly patients with chordoma at 3 and 5 years. The validation of this nomogram was completed by evaluating the calibration curve and the C-index. RESULTS: We screened a total of 658 patients and divided them into two cohort. Training cohort had 462 samples and validation cohort had 196 samples. The multivariate Cox proportional hazards model of the training group showed an association of age, tumor size, histology, primary site, surgery, and extent of disease with OS rates. Based on these results, we constructed the corresponding nomogram. The calibration curve and C-index showed the satisfactory ability of the nomogram in terms of predictive ability. CONCLUSION: Nomogram can be an effective prognostic tool to assess the prognosis of middle-aged and elderly patients with chordoma and can help clinicians in medical decision-making and enable patients to receive more accurate and reasonable treatment.

Early Clinical and Radiologic Evaluation of Unilateral Biportal Endoscopic Unilateral Laminotomy and Bilateral Decompression in Degenerative Lumbar Spinal Stenosis: A Retrospective Study.

BACKGROUND: The aim of this study is to evaluate the changes in radiologic parameters and clinical outcomes following unilateral biportal endoscopic unilateral laminotomy and bilateral decompression (UBE ULBD) for treatment of central lumbar spinal stenosis. METHODS: Forty-one central lumbar spinal stenosis patients who underwent UBE ULBD were enrolled from April 2021 to February 2023. Visual analog scale (VAS) for back pain and leg pain, Oswestry Disability Index (ODI) score, and the modified MacNab criteria were assessed preoperatively and postoperatively. The preoperative and postoperative cross-sectional area of the spinal canal (CSAC), anteroposterior diameter, horizontal width, and ipsilateral and contralateral lateral recess height were calculated from axial computed tomography (CT) scans. Percentage of facet joint preservation measured on axial CT scans was obtained preoperation and postoperation. RESULTS: The VAS for back and leg pain improved from 7.24 ± 0.80 and 7.59 ± 0.59 preoperatively to 2.41 ± 0.55 and 2.37 ± 0.62 (p < 0.05) postoperatively and 1.37 ± 0.54 and 1.51 ± 0.55 at the last follow-up (p < 0.05). For ODI, improvement from 60.37 ± 4.44 preoperatively to 18.90 ± 4.66 (p < 0.05) at the last follow-up was observed. CT scans demonstrated that the postoperative CSAC increased significantly from 287.84 ± 87.81 to 232.97 ± 88.42 mm (p < 0.05). The mean postoperative anteroposterior diameter and horizontal width increased significantly from 18.01 ± 3.13 and 19.57 ± 3.80 to 22.19 ± 4.56 and 21.04 ± 3.72 mm, respectively (p < 0.05). The ipsilateral lateral recess height and contralateral lateral recess height were 3.39 ± 1.12 and 3.20 ± 1.14 mm preoperatively and 4.03 ± 1.37 and 3.83 ± 1.32 mm (p < 0.05) postoperatively, with significant differences. The ipsilateral and contralateral facet joint preservations were 88.17 and 93.18%, respectively. CONCLUSION: The UBE ULBD surgery is a safe and effective treatment for central lumbar spinal stenosis, associated with significant improvement in clinical outcomes and radiologic parameters. Studies with larger samples and longer follow-up periods are needed for further research.

Is Full-Endoscopic Transforaminal Lumbar Interbody Fusion Superior to Open Transforaminal Lumbar Interbody Fusion for Single-Level Degenerative Lumbar Spondylolisthesis? A Retrospective Study.

BACKGROUND: In this study, we evaluate the clinical efficacy and safety of full-endoscopic transforaminal lumbar interbody fusion (TLIF) for treatment of single-level lumbar degenerative spondylolisthesis. METHODS: Fifty-three patients were divided into two groups according to the surgical techniques: Full endoscopic (Endo)-TLIF (n = 25) and TLIF (n = 28). Clinical efficacy was evaluated pre- and postoperatively. The operation time, operative blood loss, postoperative amount of serum creatine phosphokinase (CPK), postoperative drainage volume, postoperative hospital stay time, total cost, and operative complications were also recorded. RESULTS: Compared with the TLIF group, the Endo-TLIF group had similar intraoperative blood loss, less postoperative increased CPK, less postoperative drainage volume, and shorter postoperative hospital stay, but longer operative time and higher total cost. The postoperative visual analog scale (VAS) scores of back and leg pain and Oswestry Disability Index (ODI) scores significantly improved compared with the preoperative scores in both two groups; more significant improvement of postoperative VAS scores of back pain and ODI scores were shown in the Endo-TLIF group at the 1-month follow-up (p < 0.05). No difference was found in the intervertebral fusion rate between the two groups. CONCLUSION: The Endo-TLIF has similar clinical effect compared with the TLIF for the treatment of lumbar degenerative spondylolisthesis. It also has many surgical advantages such as less muscle trauma, less postoperative back pain, and fast functional recovery of the patient. However, steep learning curve, longer operative time, and higher total cost may be the disadvantages that limit this technique. Also, the Endo-TLIF treatment of patients with bilateral lateral recess stenosis is considered a relative contraindication.

CK1ε drives osteogenic differentiation of bone marrow mesenchymal stem cells via activating Wnt/ß-catenin pathway.

The treatment of bone defects is a difficult problem in orthopedics. At present, the treatment mainly relies on autologous or allogeneic bone transplantation, which may lead to some complications such as foreign body rejection, local infection, pain, or numbness at the bone donor site. Local injection of conservative therapy to treat bone defects is one of the research hotspots at present. Bone marrow mesenchymal stem cells (BMSCs) can self-renew, significantly proliferate, and differentiate into various types of cells. Although it has been reported that CK1ε could mediate the Wnt/ß-catenin pathway, leading to the development of the diseases, whether CK1ε plays a role in bone regeneration through the Wnt/ß-catenin pathway has rarely been reported. The purpose of this study was to investigate whether CK1ε was involved in the osteogenic differentiation (OD) of BMSCs through the Wnt/ß-catenin pathway and explore the mechanism. We used quantitative reverse transcription-polymerase chain reaction (qRT-qPCR), Western blots, immunofluorescence, alkaline phosphatase, and alizarin red staining to detect the effect of CK1ε on the OD of BMSCs and the Wnt/ß-catenin signaling pathway. CK1ε was highly expressed in BMSCs with OD, and our study further demonstrated that CK1ε might promote the OD of BMSCs by activating DLV2 phosphorylation, initiating Wnt signaling downstream, and activating ß-catenin nuclear transfer. In addition, by locally injecting a CK1ε-carrying adeno-associated virus (AAV5- CK1ε) into a femoral condyle defect rat model, the overexpression of CK1ε significantly promoted bone repair. Our data show that CK1ε was involved in the regulation of OD by mediating Wnt/ß-catenin. This may provide a new strategy for the treatment of bone defects.

Percutaneous Curved Vertebroplasty and Bilateral-Pedicle-Approach Percutaneous Vertebroplasty in the Treatment of Osteoporotic Vertebral Compression Fracture: A Meta-Analysis.

Introduction: The aim of this study was to evaluate the use of percutaneous curved vertebroplasty procedure (PCVP) and bilateral-pedicle-approach percutaneous vertebroplasty (bPVP) for the treatment of osteoporotic vertebral compression fractures (OVCFs) through a systematic review and meta-analysis of the scientific literature. Methods: A systematic review of the scientific literature in PubMed, China National Knowledge Infrastructure (CNKI), Wanfang and other databases was conducted in conjunction with different keywords. Nine studies were included; all but 3 were randomised controlled studies and all were prospective or retrospective cohort studies. Results: We observed statistically significant differences between the PCVP group and the bPCVP group in terms of postoperative visual analogue scale (VAS) scores (mean difference [MD]: -.08; 95% confidence intervals [CI]: -.15 to .00), bone cement leakage rates (OR = .33; 95%CI: .20 to .54), bone cement injection (MD: -1.52; 95%CI: -1.58 to 1.45), operative times (MD: -16.69; 95%CI: -17.40 to -15.99) and intraoperative fluoroscopies (MD: -8.16; 95%CI: -9.56 to -6.67), with the PCVP group being more dominant. There were no statistical differences in postoperative Oswestry Disability Index (ODI) scores (MD: -.72; 95%CI: -2.11 to .67) and overall bone cement distribution rates (MD: 2.14; 95%CI: .99 to 4.65) between the 2 groups. Conclusions: Meta-analysis showed more favourable outcomes in the PCVP group compared to the bPVP group. PCVP might be effective and safe in the treatment of OVCFs because it relieves postoperative patient pain, reduces operative time and cement injection, and decreases the risk of cement leakage and radiation exposure to the surgeon and patient.

Development and validation of a nomogram for predicting prognosis of high-grade chondrosarcoma: A surveillance, epidemiology, and end results-based population analysis.

BACKGROUND: The incidence of chondrosarcoma is increasing every year, and the treatment and prognosis of patients with high-grade chondrosarcoma are becoming more and more important. Nomogram is a tool that can quickly and easily predict the overall survival of tumor patients. Therefore, the development and validation of a nomogram to predict overall survival in patients with high-grade chondrosarcoma was desired. METHODS: We retrospectively collected 396 patients with high-grade chondrosarcoma from the Surveillance, Epidemiology, and End Results (SEER) database from 2004 to 2015. Randomly divided into model and validation groups, the best cut-off values for age and tumor size grouping were derived by using X-tile software. Then, independent prognostic factors for high-grade chondrosarcoma were derived by SPSS.26 univariate and multivariate Cox analyses analysis in the model group, and the model was evaluated by using R software, using C-indix and ROC curves, and finally these independent prognostic factors were included in Nomogram. RESULTS: 396 patients were randomly assigned to the modelling group (n = 280) or the validation group (n = 116). Age, tissue-type, tumor size, AJCC stage, regional expansion and surgery were identified as independent prognostic factors (p < 0.05) which further combined to construct a nomogram. The C-index of internal validation for overall survival(OS) was 0.757, while the C-index of external validation for overall survival(OS) was 0.832. Both internal and external calibration curves show a good agreement between nomogram prediction and actual survival. CONCLUSION: In this study, we established age, tumour size, AJCC stage, tissue type, surgery and tumor extension as independent prognostic factors for high-grade chondrosarcoma and constructed a nomogram to predict 3- and 5-year survival rates for high-grade chondrosarcoma.

Local Anesthesia Versus General Anesthesia in Percutaneous Interlaminar Endoscopic Discectomy: A Meta-analysis.

OBJECTIVE: The objective of this study was to systematically evaluate the safety and efficacy of local anesthesia (LA) and general anesthesia (GA) in percutaneous interlaminar endoscopic discectomy (PIED). MATERIALS AND METHODS: We searched MEDLINE, EMBASE, EuropePMC, PubMed, Web of Science, Cochrane databases, and CNKI databases for all relevant studies. All statistical analysis was performed using Review Manager version 5.3. RESULTS: A total of 6 articles with 549 study participants were included, with 282 patients in LA group and 267 patients in GA group. The results of the meta-analysis showed that the LA group had significantly better results in hospital stay time (mean difference [MD], -1.68; 95% CI, -3.35 to -0.01) and hospital costs (MD, -0.57, 95% CI, -1.02 to -0.12) compared with the GA group; whereas Oswestry Disability Index (MD, 0.48; 95% CI, -0.07 to 1.04), Visual Analog Scale Scores (MD, -0.05; 95% CI, -0.24 to 0.13), postoperative transient dysesthesia and weakness (odds ratio [OR], 0.83, 95% CI, 0.40 to 1.69), dura and nerve root injury (OR, 0.21, 95% CI, 0.03 to 1.25), operation time (MD, -3.51; 95% CI, -11.5 to 4.48), and willingness rate to receive the same procedure(OR, 0.12, 95% CI, 0.01 to 1.00) showed no significant differences between the 2 groups. DISCUSSION: LA can effectively relieve pain during PIED surgery and ensure the safety of operation without increasing the occurrence of postoperative complications. PIED under LA not only has similar patient satisfaction but also shows obvious advantages in shortening hospital stay and reducing hospital costs compared with GA surgery.

Effects of periodic mechanical stress on cytoskeleton dependent lipid raft-induced integrin ɑ1 activation in rat nucleus pulposus cells.

Extracellular matrix (ECM) production and nucleus pulposus (NP) cell migration increase under periodic mechanical stress (PMS), but the underpinning regulatory mechanism remains unclear. This work aimed to examine the regulatory effects of cytoskeleton-lipid raft-integrin α1 signaling in NP cells exposed to PMS. Briefly, In NP cells, cytoskeleton rearrangement, lipid raft aggregation and integrin α1 expression in the stress and control groups were assessed by immunofluorescent staining and immunoblot. In addition, cell migration and ECM gene expression were detected by a scratch test and quantitative reverse transcription polymerase chain reaction (qRT­PCR), respectively. As a result, PMS up-regulated ECM gene expression and enhanced NP cell migration (both P < 0.05), accompanied by increased integrin α1, lipid raft, caveolin-3, F-actin and ß-tubulin amounts. Pretreatment with the lipid raft inhibitor methyl-ß-cyclodextrin (MßCD) or small interfering RNA (siRNA) targeting caveolin-3 resulted in decreased ECM mRNA synthesis and cell migration induced by PMS (both P < 0.05); meanwhile, integrin α1 expression was also reduced. F-actin and ß-tubulin inhibition by cytochalasin D and colchicine, respectively, not only reduced ECM mRNA synthesis and cell migration (both P < 0.05), but also disrupted lipid raft and caveolin-3 amount increases induced by PMS in NP cells. In conclusion, PMS promotes ECM mRNA up-regulation and cell migration through the cytoskeleton-lipid raft-integrin α1 signaling pathway, inhibiting cytoskeleton and lipid rafts could block the cellular effects.

Removal of collagen three-dimensional scaffold bubbles utilizing a vacuum suction technique.

The process of generating type I/II collagen scaffolds is fraught with bubble formation, which can interfere with the three-dimensional structure of the scaffold. Herein, we applied low-temperature vacuum freeze-drying to remove mixed air bubbles under negative pressure. Type I and II rubber sponges were acid-solubilized via acid lysis and enzymolysis. Thereafter, vacuum negative pressure was applied to remove bubbles, and the cover glass press method was applied to shape the type I/II original scaffold. Vacuum negative pressure was applied for a second time to remove any residual bubbles. Subsequent application of carbamide/N-hydroxysuccinimide cross-linked the scaffold. The traditional method was used as the control group. The structure and number of residual bubbles and pore sizes of the two scaffolds were compared. Based on the relationship between the pressure and the number of residual bubbles, a curve was created, and the time of ice formation was calculated. The bubble content of the experimental group was significantly lower than that of the control group (P < 0.05). The pore diameter of the type I/II collagen scaffold was higher in the experimental group than in the control group. The time of icing effect of type I and II collagen solution was 136.54 ± 5.26 and 144.40 ± 6.45 s, respectively. The experimental scaffold had a more regular structure with actively proliferating chondrocytes that possessed adherent pseudopodia. The findings indicated that the vacuum negative pressure method did not affect the physical or chemical properties of collagen, and these scaffolds exhibited good biocompatibility with chondrocytes.

Construction of tissue-engineered nucleus pulposus by stimulation with periodic mechanical stress and BMP-2.

Intervertebral disc (IVD) degeneration, which is common among elderly individuals, mainly manifests as low back pain and is caused by structural deterioration of the nucleus pulposus (NP) due to physiological mechanical stress. NP mesenchymal stem cells (NPMSCs) around the IVD endplate have multidirectional differentiation potential and can be used for tissue repair. To define favorable conditions for NPMSC proliferation and differentiation into chondroid cells for NP repair, the present study simulated periodic mechanical stress (PMS) of the NP under physiological conditions using MSC chondrogenic differentiation medium and recombinant human BMP-2 (rhBMP-2). rhBMP-2 effectively promoted NPMSC proliferation and differentiation. To clarify the mechanism of action of rhBMP-2, integrin alpha 1 (ITG A1) and BMP-2 were inhibited. PMS regulated the BMP-2/Smad1/RUNX2 pathway through ITG A1 and promoted NPMSC proliferation and differentiation. During tissue-engineered NP construction, PMS can effectively reduce osteogenic differentiation and promote extracellular matrix protein synthesis to enhance structural NP recovery.

Comparison of the Effectiveness of Simple Plate Fixation and Plate Combined with Local Fixation of Broken Ends in the Treatment of Oblique Fracture of Midshaft Clavicle.

OBJECTIVE: To compare the clinical efficacy of performing simple plate fixation with that using a plate combined with fracture end fixation to investigate the necessity of fracture end fixation outside the plate in cases of oblique fracture of the middle clavicle. METHODS: This was a retrospective follow-up study of patients with middle clavicle oblique fractures (Robinson types 2A1 and 2A2) between 2015 and 2020. Patients were divided into two groups according to their treatment options: the simple plate fixation (SPF) group (n = 79; 43 men and 36 women; average age, 46.37 ± 14.54 years) and the plate combined with fracture local fixation (PLFP) group (n = 81; 36 men and 45 women; average age, 48.42 ± 12.55 years). Intraoperative blood loss, operation time, postoperative fracture healing time, postoperative shoulder function score (Constant-Murley and disabilities of the arm, shoulder, and hand [DASH] scores), clinical complications, and postoperative subjective satisfaction were compared between the two groups. RESULTS: One hundred sixty patients with a sufficient follow-up period were included in the final analysis: 79 in the SPF group (follow-up time: 16.24 ± 3.94 months) and 81 in the PLFP group (follow-up time: 16.15 ± 3.43 months). Age, sex, body mass index, follow-up duration, fracture classification, and cause of injury were not significantly different between the two groups. There was no significant difference in blood loss, Constant-Murley and DASH scores, follow-up period, and postoperative subjective satisfaction between the two groups (P > 0.05). The fracture healing time was shorter in the PLFP group than in the SPF group (4.41 ± 0.99 vs. 4.87 ± 1.60 months, P < 0.05), but the operation duration was longer in the PLFP group than in the SPF group (65.48 ± 16.48 min, P < 0.05). There were seven (complication rate, 8.86%) and five (complication rate, 6.17%) cases that had complications in the SPF and PLFP groups, respectively. There was no significant difference in the complication rates between the two groups (P > 0.05). CONCLUSION: Although the healing time was shorter in the PLFP group than in the SPF group, the clinical efficiency of the two methods in the treatment of oblique fracture of the middle clavicle was similar.

Uniportal Full-Endoscopic versus Minimally Invasive Decompression for Lumbar Spinal Stenosis: A Meta-analysis.

BACKGROUND: In this study, we systematically analyze the effectiveness of the uniportal full-endoscopic (UPFE) and minimally invasive (MIS) decompression for treatment of lumbar spinal stenosis patients. METHODS: We performed a systematic search in Medline, Embase, Europe PMC, PubMed, Web of Science, Cochrane databases, Chinese Biomedical Literature Database, China national knowledge infrastructure, and Wanfang Data databases for all relevant studies. All statistical analyses were performed using Review Manager version 5.3. RESULTS: A total of 9 articles with 522 patients in the UPFE group and 367 patients in the MIS group were included. The results of the meta-analysis showed that the UPFE group had significantly better results in hospital stay time (mean difference [MD]: -2.05; 95% confidence interval [CI]: -2.87 to -1.23), intraoperative blood loss (MD: -36.56; 95% CI: -54.57 to -18.56), and wound-related complications (MD: -36.56; 95%CI: -54.57 to -18.56) compared with the MIS group, whereas the postoperative clinical scores (MD: -0.66; 95%CI: -1.79 to 0.47; MD: -0.75; 95%CI: -1.86 to 0.36; and MD: -4.58; 95%CI: -16.80 to 7.63), satisfaction rate (odds ratio [OR] = 1.24; 95%CI: 0.70-2.20), operation time (MD: 30.31; 95%CI: -12.55 to 73.18), complication rates for dural injury (OR = 0.60; 95%CI: 0.29-1.26), epidural hematoma (OR = 0.60; 95%CI: 0.29-1.26), and postoperative transient dysesthesia and weakness (OR = 0.73; 95%CI: 0.36-1.51) showed no significant differences between the two groups. CONCLUSIONS: The UPFE decompression is associated with shorter hospital stay time and lower intraoperative blood loss and wound-related complications compared with MIS decompression for treatment of lumbar spinal stenosis patients. The postoperative clinical scores, satisfaction rate, operation time, complication rates for dural injury, epidural hematoma, and postoperative transient dysesthesia and weakness did not differ significantly between two groups.

Transforaminal approach versus interlaminar approach: A meta-analysis of operative complication of percutaneous endoscopic lumbar discectomy.

BACKGROUND: To systematically analyze the differences of complications between percutaneous transforaminal endoscopic discectomy (PTED) and percutaneous interlaminar endoscopic discectomy (PIED) in the treatment of lumbar disc herniation. METHODS: We performed a systematic search in MEDLINE, EMBASE, PubMed, Web of Science, Cochrane databases, Chinese Biomedical Literature Database, CNKI, and Wanfang Data for all relevant studies. All statistical analysis was performed using Review Manager Version 5.3. RESULTS: A total of 15 articles with 1156 study subjects were included, with 550 patients in PTED group and 606 patients in PIED group. The results of the meta-analysis showed that postoperative dysesthesia (odds ratio [OR] = 0.61, 95% confidence interval [CI], 0.33-1.13), nerve root injury (OR = 1.22, 95% CI, 0.30-5.02), surgical site wound complications (OR = 1.26, 95% CI, 0.29-5.40), recurrence (OR = 1.09, 95% CI, 0.54-2.21), conversion to open surgery (OR = 1.26, 95% CI, 0.33-4.81), incomplete decompression (OR = 1.62, 95% CI, 0.43-6.09), and total complication (OR = 0.72, 95% CI, 0.49-1.06) showed no significant differences between the PTED group and the PIED group, while the PTED group had significantly better results in dural tear compared with the PIED group (OR = 0.31, 95% CI, 0.13-0.79). CONCLUSIONS: Dural tear was significantly less occured in PTED compared with PIED. The postoperative dysesthesia, nerve root injury, surgical site wound complications, recurrence, conversion to open surgery, incomplete decompression, and total complication did not differ significantly between PTED and PIED in the treatment of lumbar disc herniation.

Biomechanical Model Study of the Effect of Partial Facetectomy on Lumbar Stability Under Percutaneous Endoscopy.

OBJECTIVE: To investigate the effect of partial facetectomy on lumbar stability using percutaneous endoscopy. METHODS: Five male adult volunteers with no history of lumbar disease participated in the study. Based on computed tomography data, a three-dimensional model of the L3-S1 segment was created using the Mimics l5.0 and Ansys 13.0 software. The use of an 8.5-mm-diameter ring saw was simulated to cut through 5 different needle insertion points (IPs) commonly used in the clinic on the left-side facet joint (FJ) of L5 to perform facetectomy. The first to third IPs were on the apex of the superior FJ, the midpoint of the ventral side of the superior FJ, and the lowest point of the ventral side of the superior FJ. The fourth and fifth IPs represented the positions of the second and third IPs (8.5 mm/2) after the radius of the ring saw was translated to the dorsal side of the superior FJ. Physiologic load was applied to the human models. The pressure on the left and right FJ of the L5 vertebra, the pressure on the L4-5 intervertebral disc, and the range of motion of the lumbar spine were recorded when normal flexion and extension and lateral flexion and rotation of the lumbar spine model after facetectomy were simulated. RESULTS: Compared with the intact group, the second IP, maximum pressure on the L4-5 intervertebral disc after facetectomy was not significantly different under any condition (P > 0.05). The maximum pressure on the left FJ of L5 showed significant differences during right rotation of the lumbar spine (P < 0.05). The pressure on the right FJ of L5 was significantly different during left rotation of the lumbar spine (P < 0.05). The range of motion of the lumbar spine was not significantly different under any condition (P > 0.05). CONCLUSIONS: The second IP at the midpoint of the ventral side of the superior FJ showed minimal effect on lumbar spine biomechanics compared with all the other IPs during percutaneous transforaminal facetectomy. Thus, it can be considered as the most suitable IP for facetectomy.

The effect of different cross-linking conditions of EDC/NHS on type II collagen scaffolds: an in vitro evaluation.

The purpose of this paper is to analyze the properties of porcine cartilage type II collagen scaffolds crosslinked with 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide/N-hydroxy-succinamide (EDC/NHS) under different conditions. The porous EDC/NHS-crosslinked scaffolds were obtained through a two-step freeze-drying process. To determine the optimal crosslinking condition, we used different solvents and various crosslinking temperatures to prepare the scaffolds. Three crosslinking solutions were prepared with different solvents, photographs were taken with a flash in the darkroom, and light transmission was observed. Type II collagen was crosslinked on a horizontal shaker at a speed of 60 r/min according to the above grouping conditions, and then the structural change of the scaffold in each group was observed. To investigate the swelling ratio and the in vitro degradation of the collagen scaffold, tests were also carried out by immersion of the scaffolds in a PBS solution and digestion in type II collagenase, respectively. The influence of the scaffolds on the proliferation of chondrocytes was assessed by the methyl thiazolyl tetrazolium colorimetric assay. The morphology of the crosslinked scaffolds cocultured with chondrocytes was characterized by a scanning electron microscope. The results proved that 75% alcohol and a crosslinking temperature of 37 °C are recommended. Collagen fibrils are more densely packed after crosslinking with EDC/NHS and have a more uniform structure than that of noncrosslinked ones. The EDC-crosslinked scaffolds possessed excellent mechanical property and biocompatibility.

Association between interleukin-21 gene rs6822844 polymorphism and rheumatoid arthritis susceptibility.

Controversial results concerning the association between a polymorphism rs6822844 in the interleukin (IL) 21 (IL-21) gene and rheumatoid arthritis (RA) have existed. A meta-analysis to confirm above relationships is necessary to be performed immediately. We conducted a search in the PubMed database, covering all papers published up to 20 October 2018. Overall, six case-control studies with 3244 cases and 3431 healthy controls were included. Odds ratios (ORs) and 95% confidence intervals (CIs) were used to assess the strength of this association. Publication bias was assessed with both Egger's and Begg's tests. After calculation, we found that IL-21 rs6822844 polymorphism could decrease RA risk in overall genetic models (allelic contrast: OR = 0.77, 95% CI = 0.62-0.97, P=0.024; TG versus GG: OR = 0.68, 95% CI = 0.50-0.92, P=0.013, and dominant genetic model: OR = 0.72, 95% CI = 0.55-0.94, P=0.016). Similarly, stratified analysis by race, source of control, significantly decreased association was found in Asians, Caucasians and hospital-based (HB) control source. Finally, in the subgroup analysis of rheumatoid factor (RF) and anti-citrullinated protein antibody (ACPA) status, poorly decreased relationship was detected between IL-21 rs6822844 polymorphism and RF negative and ACPA positive RA risk, respectively. No obvious evidence of publication bias was detected in overall analysis. In summary, our study indicated that IL-21 rs6822844 polymorphism was significantly associated with decreased RA susceptibility.

Periodic Mechanical Stress Stimulates GIT1-Dependent Mitogenic Signals in Rat Chondrocytes Through ERK1/2 Activity.

BACKGROUND/AIMS: The mitogenic effects of periodic mechanical stress on chondrocytes have been studied extensively, but the mechanisms whereby chondrocytes sense and respond to mechanical stimuli remain to be determined. We explored the question and verified the key role of G protein coupled receptor kinase interacting protein 1 (GIT1) signaling in periodic mechanical stress-induced chondrocyte proliferation. METHODS: Two steps were undertaken in the experiment. In the first step, the cells were maintained under non-pressure conditions or periodic mechanical stress for 1 h prior to Western blot analysis. In the second step, the cells were pretreated with short hairpin RNA (shRNA) targeted to GIT1 or Src or control scrambled shRNA, or transfected with GIT1 wild-type or GIT1 mutant Y321F, or focal adhesion kinase (FAK) wild-type or FAK mutants Y397F or Y576F/Y577, respectively. Moreover, the cells were pretreated with blocking antibody against integrin ß1 or PP2. Then the cells were maintained under non-pressure conditions or periodic mechanical stress for 1 h prior to Western blot analysis, and for 3 days, 8 h per day, prior to direct cell counting and CCK-8 assay, respectively. RESULTS: Periodic mechanical stress significantly induced sustained phosphorylation of GIT1 at Tyr321. Reduction of GIT1 with shRNA targeted to GIT1 and GIT1 mutant Y321F inhibited periodic mechanical stress-promoted chondrocyte proliferation, accompanied by attenuated extracellular signal-regulated kinase (ERK)1/2 and FAK phosphorylation at Tyr576/577. However, activation of Src and FAK-Tyr397 was not prevented upon GIT1 suppression. Furthermore, pretreatment with blocking antibody against integrin ß1, Src-selective inhibitor, PP2, and shRNA targeted to Src blocked GIT1 activation under periodic mechanical stress. In addition, GIT1 phosphorylation at Tyr321 was not reduced upon pretreatment with FAK mutants Y397F or Y576F/Y577 under conditions of periodic mechanical stress. CONCLUSION: These findings collectively suggested that periodic mechanical stress promoted chondrocyte proliferation through at least two separate pathways, integrin ß1-Src-GIT1-FAK(Tyr576/577)-ERK1/2, and the other parallel GIT1-independent integrin ß1-FAK(Tyr397)-ERK1/2.

Periodic Mechanical Stress Induces Extracellular Matrix Expression and Migration of Rat Nucleus Pulposus Cells Through Src-GIT1-ERK1/2 Signaling Pathway.

BACKGROUND/AIMS: Periodic mechanical stress has been shown to promote extracellular matrix (ECM) synthesis and cell migration of nucleus pulposus (NP) cells, however, the mechanisms need to be fully elucidated. The present study aimed to investigate the signal transduction pathway in the regulation of NP cells under periodic mechanical stress. METHODS: Primary rat NP cells were isolated and seeded on glass slides, and then treated in our self-developed periodic stress field culture system. To further explore the mechanisms, data were analyzed by scratch-healing assay, quantitative reverse transcription polymerase chain reaction (RT-qPCR) analysis, western blotting, and co-immunoprecipitation assay. RESULTS: Under periodic mechanical stress, the mRNA expression of ECM collagen 2A1 (Col2A1) and aggrecan, and migration of NP cells were significantly increased (P < 0.05 for each), associating with increases in the phosphorylation of Src, GIT1, and ERK1/2 (P < 0.05 for each). Pretreatment with the Src inhibitor PP2 reduced periodic mechanical stress-induced ECM synthesis and cell migration of NP cells (P < 0.05 for each), while the phosphorylation of GIT1 and ERK1/2 were inhibited. ECM synthesis, cell migration, and phosphorylation of ERK1/2 were inhibited after pretreatment with the small interfering RNA for GIT1 in NP cells under periodic mechanical stress (P < 0.05 for each), whereas the phosphorylation of Src was not affected. Pretreatment with the ERK1/2 inhibitor PD98059 reduced periodic mechanical stress-induced ECM synthesis and cell migration of NP cells (P < 0.05 for each). Co-immunoprecipitation assay showed that there was a direct interaction between Src and GIT1 and between GIT1 and ERK1/2. CONCLUSION: In conclusion, periodic mechanical stress induced ECM expression and migration of NP cells via Src-GIT1-ERK1/2 signaling pathway, playing an important role in regulation of NP cells.