Jianru Wang

LIM mineralization protein-1 suppresses TNF-α induced intervertebral disc degeneration by maintaining nucleus pulposus extracellular matrix production and inhibiting matrix metalloproteinases expression

Imbalanced metabolism of Nucleus pulposus (NP) extracellular matrix (ECM) is closely correlated to Intervertebral Disc Degenerative Disease. LIM mineralization protein‐1 (LMP‐1) has been proven to induce sulfated glycosaminoglycan (sGAG) production in NP and have an anti‐inflammatory effect in pre‐osteoclast. However, whether it has any effect on the NP ECM production and degradation under inflammatory stimulation has not been studied. In the current study, a TNF‐α induced cell model was established in vitro. Lentivirus encoding LMP‐1 (LV‐LMP‐1) and short heparin LMP‐1 (LV‐shLMP‐1) were constructed to overexpress and knockdown LMP‐1 expression in NP cells. LMP‐1 mRNA level was regulated in a dose‐dependent manner after transfection. LV‐LMP‐1 increased whereas LV‐shLMP‐1 decreased collagen II, aggrecan, versican expression, and sGAG production. LV‐LMP‐1 abolished while LV‐shLMP‐1 aggravated TNF‐α mediated down‐regulation of the above matrix genes via ERK1/2 activation. Moreover, LV‐LMP‐1 abrogated TNF‐α induced MMP‐3 and MMP‐13 expression via inhibiting p65 translocation and MMP‐3 and MMP‐13 promoter activity. These results indicated that LMP‐1 had an ECM production maintenance effect under inflammatory stimulation. This effect was via up‐regulation of matrix genes expression at least partially through ERK1/2 activation, and down‐regulation of MMPs expression through NF‐κB inhibition.

Comparison of Smith-Petersen osteotomy and pedicle subtraction osteotomy for the correction of thoracolumbar kyphotic deformity in ankylosing spondylitis: a systematic review and meta-analysis.

Study Design. A systematic review and meta-analysis. Objective. To compare the efficacy and safety outcomes of Smith-Petersen osteotomy (SPO) and pedicle subtraction osteotomy (PSO) for patients with ankylosing spondylitis (AS) with thoracolumbar kyphotic deformity. Summary of Background Data. Both SPO and PSO are used to correct thoracolumbar kyphotic deformity due to AS. Evidence is insufficient to determine which has better efficacy and safety outcomes. Methods. A systematic literature search was performed. Studies concentrating on treating thoracolumbar kyphotic deformity due to AS with SPO and/or PSO were included. Efficacy was determined with radiographical outcomes, including sagittal vertical axis and lumbar lordosis. Safety was determined with complication rates. The data were analyzed with Review Manager and R software. Results. Twenty-three studies were included. Among them, 5 were comparative studies and were used for a meta-analysis. All 23 studies were pooled to evaluate the radiographical correction and incidence of complications. The meta-analysis of the 5 comparative studies showed no significant difference between groups in either correction of sagittal vertical axis and lumbar lordosis or incidence of complications. The pooled data also showed similar radiological correction and complication rates between SPO and PSO. SPO was found to have potential risk of aortic rupture and slightly higher risk of permanent neurological deficit without statistical significance, whereas PSO was shown longer operative time and more blood loss. Conclusion. This systematic review and meta-analysis demonstrates that both SPO and PSO are effective in correcting thoracolumbar kyphotic deformity in AS and have similar risk of most complications. Aortic rupture and related death during correction is reported in SPO and should be taken into consideration for decision making. Level of Evidence: 4

Both Expression of Cytokines and Posterior Annulus Fibrosus Rupture Are Essential for Pain Behavior Changes Induced by Degenerative Intervertebral Disc: An Experimental Study in Rats

The aim of this study was to analyze the relationship between intervertebral disc degeneration and low back pain (LBP). Rat L4/5 disc degeneration model was established by annular puncture using a 0.4 mm needle anteriorly or posteriorly. In both anterior and posterior puncture models, magnetic resonance imaging (MRI) and histological analyses revealed marked disc degeneration 2 weeks after puncture. Cytokine expression was up‐regulated in different level in nucleus pulposus (NP) from 3 days after puncture. Pain behavioral tests indicated that the anterior disc puncture did not induce pain behavior changes, whereas the posterior disc puncture resulted in mechanical allodynia from 1 day to 21 days after injury. Besides, cytokine expression was significantly increased in dorsal root ganglion (DRG) at 1 and 2 weeks after posterior puncture, but not after the anterior puncture. These findings indicate the NP of the degenerative disc expresses different levels of inflammatory cytokines, and posterior disc puncture produced mechanical allodynia. The expression phase of cytokines in the NP was accordance with mechanical hyperalgesia in the posterior disc puncture model. Both expression of cytokines and posterior annulus fibrosus (AF) rupture in degenerative intervertebral disc are essential for pain behavior changes.

TGF-β1 antagonizes TNF-α induced up-regulation of matrix metalloproteinase 3 in nucleus pulposus cells: role of the ERK1/2 pathway

Abstract Tumor necrosis factor-α (TNF-α) has been shown to have a catabolic effect on intervertebral disc degeneration (IVDD), including increasing MMP3 expression and subsequent extracellular matrix (ECM) degradation. In contrast, transforming growth factor-β1 (TGF-β1) has an anabolic effect on nucleus pulposus (NP) cells. However, the anti-catabolic effect of TGF-β1 under inflammatory condition is unknown. The aim of this study was to demonstrate whether TGF-β1 can reverse TNF-α-induced MMP3 increase in NP cells and to further investigate the underlying mechanisms. The transcriptional activity, gene expression, and protein levels of MMP3 were measured by luciferase reporter assay, qRT-PCR and western blot, respectively. TNF-α increased MMP3 expression in rat NP cells time and dose dependently. TGF-β1 could abolish TNF-α-mediated up-regulation of collagen I and MMP3 expression, and down-regulate aggrecan and collagen II expression. The ERK1/2 signaling pathway was activated after exposure to TGF-β1. Treatment with ERK1/2 inhibitors (PD98059 and U0126) abolished the antagonistic effect of TGF-β1 on TNF-α mediated catabolic responses. These findings provide novel evidence supporting the anti-catabolic role of TGF-β1 in IVDD, which is important for the potential clinical application of TGF-β1 in disc degenerative disorders.

LIM Mineralization Protein-1 Enhances Bone Morphogenetic Protein-2–Mediated Osteogenesis Through Activation of ERK1/2 MAPK Pathway and Upregulation of Runx2 Transactivity

LIM mineralization protein‐1 (LMP‐1) is an intracellular regulator of bone formation. Upregulation of bone morphogenetic proteins (BMPs) and stabilization of BMP/Smad signaling have been proven to be the key mechanisms through which LMP‐1 enhances osteogenesis. However, how LMP‐1 regulates BMPs expression and related bone formation remains unclear. In this study, a LMP‐1–induced osteogenesis cell model was used to study the molecular action of LMP‐1 on BMP‐2 expression and bone formation. The results show that overexpression of LMP‐1 significantly increases, whereas downregulation of endogenous LMP‐1 decreases BMP‐2 expression and bone formation. Antagonism of BMP‐2 with noggin or short hairpin BMP‐2 significantly attenuates the osteoinductive effect of LMP‐1, suggesting that the osteoinductive effect of LMP‐1 is mediated by BMP‐2. LMP‐1 regulation of BMP‐2 is found to occur at the transcription level using a luciferase reporter assay with a reporter construct containing a BMP‐2 promoter. A promoter deletion assay reveals that –1000/–500 bp is the key regulated region by LMP‐1. A Runx2‐binding site is then located at –934/–920 bp and confirmed by luciferase assay using a reporter construct containing repeats of this Runx2‐binding site and the site‐directed mutagenesis analysis. Overexpression of LMP‐1 significantly increases Runx2 expression. Downregulation of Runx2 expression significantly decreases BMP‐2 promoter activity and BMP‐2 expression. A ChIP assay demonstrates that LMP‐1 increases the interaction between Runx2 and BMP‐2 promoter. A luciferase reporter assay using the OSE2 promoter containing a Runx2‐binding site confirms that Runx2 transactivity can be upregulated by LMP‐1. Moreover, inhibiting the activation of different pathways with specific pathway inhibitors reveals that ERK1/2 MAPK activation is essential for LMP‐1–induced upregulation of Runx2 transactivity and subsequent BMP‐2 expression. In conclusion, our novel findings describe a positive regulatory effect of LMP‐1 on BMP‐2 expression and BMP‐2–mediated osteogenesis. This effect occurs through activation of ERK1/2 pathway and subsequent upregulation of Runx2 transactivity.

TNF-α and TGF-β1 regulate Syndecan-4 expression in nucleus pulposus cells: role of the mitogen-activated protein kinase and NF-κB pathways

Abstract Syndecan-4 is emerging as an important player in cell interaction with the extracellular environment and has been shown to be involved in the progression of intervertebral disc degeneration. However, the mechanism of syndecan-4 regulation by TNF-α and the role of TGF-β1 in regulating syndecan-4 expression remain poorly understood in nucleus pulposus (NP) cells. The aim of this study was to investigate these mechanisms. We exposed NP cells to TNF-α and the gene, protein expression, and promoter activity levels of syndecan-4 were measured by qPCR, western blotting, and the luciferase reporter assay, respectively. The activation of the MAPK and NF-κB pathways was detected using western blot analysis. Syndecan-4 expression in rat NP cells was increased by TNF-α, but this was neither time nor dose dependent in response to TNF-α. ERK1/2, JNK, and NF-κB pathways were activated following TNF-α treatment. Treatment with ERK1/2 and NF-κB inhibitors decreased the up-regulation of syndecan-4 by TNF-α. However, JNK inhibition showed no effect on syndecan-4 expression induced by TNF-α. TNF-α mediated up-regulation of syndecan-4 was antagonized by TGF-β1. This study provided evidence for the differential regulation by MAPK and NF-κB pathways in the over-expression of syndecan-4 promoted by TNF-α in NP cells. Our results demonstrate that TGF-β1 exerts anabolic effects on intervertebral discs by inhibiting the expression of syndecan-4.

Biomechanical effect of 4-rod technique on lumbosacral fixation: an in vitro human cadaveric investigation.

Study Design. An in vitro biomechanical study of 3 lumbosacral fixation techniques in human cadaveric lumbar-pelvic spine models. Objective. To compare the in vitro biomechanical effect of a novel 4-rod lumbosacral reconstruction technique with conventional techniques in a human cadaveric lumbopelvic model, and to evaluate the benefit of adding supplementary rod fixation. Summary of Background Data. Spinopelvic fixation involving the sacrum remains a difficult clinical challenge. Numerous lumbopelvic reconstruction methods based on the Galveston 2-rod technique have been proposed. Recently, a novel technique using supporting longitudinal rods across the lumbopelvic junction was reported. However, no comparative in vitro biomechanical testing was performed to evaluate the benefit of adding supplementary fixation at the L5–S1 levels. Methods. Seven fresh-frozen cadaveric lumbar-pelvic spines were prepared and tested for bone mineral density. The intact cadavers underwent a flexibility test, followed by insertion of the instrumented construct. Three constructs were tested: S1 screws alone (group 1), S1 screws plus iliac screws (group 2), and the 4-rod technique (group 3). Rotational angles of the L1–S1 and L5–S1 segments were measured to study the stability of the 3 lumbosacral fixation constructs compared with the intact spine. Nondestructive, multidirectional flexibility tests that included 4 loading methods followed by a destructive flexural load to failure were performed using an material testing machine. The lumbosacral peak range of motion (ROM) (millimeters or degrees) and ultimate failure load (Nm) of the 3 reconstruction techniques were statistically compared using a 1-way analysis of variance combined with a Student-Newman-Keuls post hoc test. Results. The average bone mineral density of the 7 specimens was 0.81 ± 0.09 g/cm2. The ROM of the 3 fixation constructs was significantly smaller than that of the intact group in all 6 directions (P < 0.05). In lateral bending, the ROM of groups 2 and 3 was significantly smaller than that of group 1 (P < 0.05), but groups 2 and 3 were not significantly different from each other (P > 0.05). In flexion-extension, the ROM of groups 1 and 3 was significantly smaller than group 2 (P < 0.05), but groups 1 and 3 were not significantly different from each other (P > 0.05). In axial rotation, the ROM of group 3 was significantly smaller than those of groups 1 and 2 (P < 0.05), but groups 1 and 2 were not significantly different from each other (P > 0.05). Conclusion. The 4-rod technique achieved stable biomechanical effects in lumbosacral fixation. At the L5–S1 junction, the 4-rod technique demonstrated better stability than the constructs using S1 screws or S1 screws plus iliac screws. Level of Evidence: N/A

Halo-gravity traction in the treatment of severe spinal deformity: a systematic review and meta-analysis

PurposeHalo-gravity traction has been reported to successfully assist in managing severe spinal deformity. This is a systematic review of all studies on halo-gravity traction in the treatment of spinal deformity to provide information for clinical practice.MethodsA comprehensive search was conducted for articles on halo-gravity traction in the treatment of spinal deformity according to the PRISMA guidelines. Appropriate studies would be included and analyzed. Preoperative correction rate of spinal deformity, change of pulmonary function and prevalence of complications were the main measurements.ResultsSixteen studies, a total of 351 patients, were included in this review. Generally, the initial Cobb angle was 101.1° in the coronal plane and 80.5° in the sagittal plane, and it was corrected to 49.4° and 56.0° after final spinal fusion. The preoperative correction due to traction alone was 24.1 and 19.3%, respectively. With traction, the flexibility improved 6.1% but postoperatively the patients did not have better correction. Less aggressive procedures and improved pulmonary function were observed in patients with traction. The prevalence of traction-related complications was 22% and three cases of neurologic complication related to traction were noted. The prevalence of total complications related to surgery was 32% and that of neurologic complications was 1%.ConclusionPartial correction could be achieved preoperatively with halo-gravity traction, and it may help decrease aggressive procedures, improve preoperative pulmonary function, and reduce neurologic complications. However, traction could not increase preoperative flexibility or final correction. Traction-related complications, although usually not severe, were not rare.

Resistin Promotes Intervertebral Disc Degeneration by Upregulation of ADAMTS-5 Through p38 MAPK Signaling Pathway.

Study Design. Rat nucleus pulposus (NP) cells were activated with resistin with or without p38 mitogen-activated protein kinase (MAPK) pathway inhibition. The expression of a disintegrin and metalloprotease with thrombospondin motif-5 (ADAMTS-5), which plays an important role in intervertebral disc degeneration (IDD), was determined. Objective. The aim of this study was to demonstrate whether resistin can influence the ADAMTS-5 expression and to further investigate the underlying mechanisms. Summary of Background Data. Obesity has been demonstrated to promote IDD, whereas the exact mechanism remains poorly understood. Resistin, as an important adipokine, is increased with obesity and has been shown to play pro-inflammatory and catabolic role in cartilage metabolism. However, the effect of resistin on the catabolic enzymes within NP cells remains unknown. Methods. We exposed NP cells to resistin, and the transcriptional activity, gene expression, and protein levels of ADAMTS-5 were measured by luciferase reporter assay, qRT-polymerase chain reaction, immunofluorescence, and western blot, respectively. The activation of p38 MAPK pathways was detected using western blot analysis. Results. Resistin had no effect on cell viability. Resistin increased ADAMTS-5 expression in rat NP cells time and dose dependently. The p38 MAPK signaling pathway was activated after exposure to resistin. Treatment with p38 inhibitor decreased the upregulation of ADAMTS-5 by resistin. Conclusion. The current study, for the first time, investigated the role of resistin in ADAMTS-5 regulation in IDD. These findings provide novel evidence supporting the causative role of obesity in IDD, which is important to develop novel preventative or therapeutic treatment in disc degenerative disorders. Level of Evidence: N/A

Experience of Intraoperative Cell Salvage in Surgical Correction of Spinal Deformity: A Retrospective Review of 124 Patients.

AbstractThe effect of intraoperative cell salvage (ICS) in surgical correction of spinal deformity remained controversial. This study was to quantitatively demonstrate its effect. In all, 124 patients having ICS in surgical correction of spinal deformity were included. These patients would be divided into 3 groups. Group 1—blood loss less than 15 mL/kg; group 2—between 15 and 37.5 mL/kg; and group 3—more than 37.5 mL/kg. The mean blood loss was 37.2 mL/kg and patients received 872.2 mL salvaged blood on average. The prevalence of intraoperative transfusion of allogenic RBC was 62.9% and the amount averaged 3.4 U. In groups 1 to 3, the prevalence of intraoperative allogenic transfusion was 23.5%, 66.7%, and 100%, respectively. Logistic analysis showed blood loss minus autotransfusion was of significance in predicting intraoperative transfusion, whereas the blood loss or autotransfusion alone was not, implicating an important role of ICS in saving allogenic RBC. The maximum decrease of hemoglobin after operation occurred in the third day, and the magnitude was 45.7 g/L. No severe complications related to ICS were observed. In summary, ICS could decrease the amount of allogenic transfusion in surgical correction of spinal deformity. However, in terms of reducing prevalence of allogenic transfusion, it had a protective effect only in patients with small blood loss.