Biodegradable bilayer hydrogel membranes loaded with bazedoxifene attenuate blood-spinal cord barrier disruption via the NF-κB pathway after acute spinal cord injury.

After spinal cord injury (SCI), blood-spinal cord barrier (BSCB) disruption and hemorrhage lead to blood cell infiltration and progressive secondary injuries. Therefore, early restoration of the BSCB represents a key step in the treatment of SCI. Bazedoxifene (BZA), a third-generation estrogen receptor modulator, has recently been reported to inhibit inflammation and alleviate blood-brain barrier disruption caused by traumatic brain injury, attracting great interest in the field of central nervous system injury and repair. However, whether BZA can attenuate BSCB disruption and contribute to SCI repair remains unknown. Here, we developed a new type of biomaterial carrier and constructed a BZA-loaded HSPT (hyaluronic acid (HA), sodium alginate (SA), polyvinyl alcohol (PVA), tetramethylpropane (TPA) material construction) (HSPT@Be) system to effectively deliver BZA to the site of SCI. We found that HSPT@Be could significantly reduce inflammation in the spinal cord in SCI rats and attenuate BSCB disruption by providing covering scaffold, inhibiting oxidative stress, and upregulating tight junction proteins, which was mediated by regulation of the NF-κB/MMP signaling pathway. Importantly, functional assessment showed the evident improvement of behavioral functions in the HSPT@Be-treated SCI rats. These results indicated that HSPT@Be can attenuate BSCB disruption via the NF-κB pathway after SCI, shedding light on its potential therapeutic benefit for SCI. STATEMENT OF SIGNIFICANCE: After spinal cord injury, blood-spinal cord barrier disruption and hemorrhage lead to blood cell infiltration and progressive secondary injuries. Bazedoxifene has recently been reported to inhibit inflammation and alleviate blood-brain barrier disruption caused by traumatic brain injury. However, whether BZA can attenuate BSCB disruption and contribute to SCI repair remains unknown. In this study, we developed a new type of biomaterial carrier and constructed a bazedoxifene-loaded HSPT (HSPT@Be) system to efficiently treat SCI. HSPT@Be could provide protective coverage, inhibit oxidative stress, and upregulate tight junction proteins through NF-κB/MMP pathway both in vivo and in vitro, therefore attenuating BSCB disruption. Our study fills the application gap of biomaterials in BSCB restoration.

Human Bone Marrow Mesenchymal Stem Cell-Derived Exosomes Attenuate Blood-Spinal Cord Barrier Disruption via the TIMP2/MMP Pathway After Acute Spinal Cord Injury.

After spinal cord injury (SCI), destruction of the blood-spinal cord barrier (BSCB) results in infiltration of blood cells, such as neutrophils and macrophages, leading to permanent neurological dysfunction. Previous studies have shown that human bone marrow mesenchymal stem cell (BMSC)-derived exosomes have a beneficial neuroprotective effect in SCI models. However, whether BMSC-Exos contribute to the integrity of the BSCB has not been clarified. The purpose of this study was to investigate the mechanism of BMSC-Exo-induced changes in the permeability of the BSCB after SCI. Here, we first used BMSC-Exos to treat an SCI rat model, showing that BMSC-Exos can inhibit BSCB permeability damage and improve spontaneous repair. Next, we found that tissue inhibitors of matrix metalloproteinase 2 (TIMP2) have been shown to play an important role in the function of BMSC-Exos by inhibiting the matrix metalloproteinase (MMP) pathway, thereby reducing the reduction of cell junction proteins. Therefore, we constructed siTIMP2 to knock out TIMP2 in BMSC-Exos, which caused the activity of BMSC-Exos to be significantly weakened. Finally, we constructed an in vitro model of BSCB with HBMECs and verified that TIMP2 in BMSC-Exos in vitro can also alleviate BSCB damage. This proof-of-principle study demonstrates that BMSC-Exos can preserve the integrity of the BSCB and improve functional recovery after SCI through the TIMP2/MMP signaling pathway.

One stage posterior pedicle screw fixation combined with transpedicle intervertebrae titanic mesh autograft for type C thoracolumbar fractures / 中华创伤杂志

Objective To evaluate the therapeutic effeet of one stage posterior pedicle screw fixation combined with transpedicle intervertebrae titanic mesh autograft versus traditional posterior and anterior approach surgery in the treatment of severe thoracolumbar fractures.Methods A retrospective case-control study was done on 40 cases of type C thoracolumbar fractures admitted from January 2012 to December 2015.There were 28 males and 12 females,with age range of 20-48 years (mean,30.6 years).The fractures were located at T11 in 4 cases,at T12 in 16,at L1 in 14,and at L2 in 6.All cases were divided into two groups (with 20 cases per group) according to treatment method difference.The cases in posterior group had one stage posterior pedicle screw fixation combined with transpedicle intervertebrae titanic mesh autograft,and the others in posterior and anterior group were treated by traditional posterior and anterior approach surgery.The operation duration,volume of blood loss,hospital stay,kyphosis correction rate,visual analogue scale (VAS) and Oswestry disability index (ODI) were compared between the two groups.Results All patients were followed up for 10-46 months (mean,28.6 months).In posterior group,the average operation time was 154 minutes,the average blood loss was 564 ml,the postoperative suction drainage was 180.5 ml,the time period between surgery and recovery of walking ability was 5.9 days,and the hospital stay was 10.6 days.While in posterior and anterior group,the average operation time was 248.5 minutes,with the average blood loss of 960.8 ml,the postoperative suction drainage of 359.2 ml,the time duration between surgery and recovery of walking ability of 8.4 days,and the hospital stay of 14.5 days (P ＜ 0.05).At one week and six months postoperatively,the height ratio of anterior edge,Cobb angle,VAS and ODI in both groups were improved compared to the preoperative status (P ＜ 0.05).But there was no significant difference of these indicators between two groups (P ＞ 0.05) except for lumbar back pain one week after operation (P ＞ 0.05).Conclusions Through single pathway of posterior approach,one stage posterior pedicle screw fixation combined with transpedicle intervertebrae titanic mesh autograft can complete reduction of fractured vertebral body,spinal cord decompression,and anterior-middle column stability reconstruction.Compared with traditional combined posterior and anterior approach surgery,this technique has many advantages including simpler manipulation,less invasion,shorter rehabilitation time and equal bony fusion and hence is an ideal option for type C thoracolumbar fractures.

Unilateral atlantoaxial pedicle screw fixation plus structural iliac bone graft for treatment of unstable atlas fractures / 中华创伤杂志

Objective To evaluate the efficacy of unilateral atlanto-axial transpedicle screw fixation plus iliac bone graft for treatment of unstable atlas fractures combined with unilateral pedicle dysplasia or comminuted fractures.Methods A retrospective case control study was made on 44 patients with unstable atlas fractures surgically treated between January 2012 to June 2016.Unilateral atlanto-axial transpedicle screw fixation combined with iliac bone graft was performed for 22 patients combined with unilateral pedicle dysplasia or comminuted fractures in Group A[15 males,seven females;(37.5 ± 13.4)years],and bilateral atlanto-axial transpedicle screw fixation combined with iliac bone graft was performed for 22 patients without unilateral pedicle dysplasia or comminuted fractures in Group B [14 males,eight females;(38.1 ± 13.3)years].Between-group differences were compared concerning operation time,intraoperative blood loss,length of hospital stay,success rate of screw placement,postoperative atlantoaxial stability,surgery-related complications,visual analog scale (VAS),Japanese orthopedic association score (JOA) and bone fusion.Results Mean duration of follow-up was 28.4 months (range,14-48 months).In Group A,operation time was (123.4 ± 18.2) min,blood loss was (218.5 ± 80.2) ml,hospital stay was (7.1 ± 1.0)d,success rate of screw placement was 100％,postoperative atlanto-axial stability of all patients was obtained,and no complications occurred.In Group B,operation time was (173.4 ± 12.4) min,blood loss was (318.2 ± 61.7) ml,hospital stay was (7.2 ± 0.8) d,success rate of screw placement was 100％,postoperative atlanto-axial stability of all patients was obtained,and no complications occurred.There were significant differences in operation time and blood loss between the two groups (P ＜0.01),while not in hospital stay,success rate,postoperative atlant-oaxial stability,complication incidence,VAS and JOA (P ＞ 0.05).Conclusion Both treatments are effective,but unilateral atlanto-axial transpedicle screw fixation combined with iliac bone graft is associated with relatively shorter operation time and less blood loss and hence is considered as a better choice for treatment of unstable atlas fractures.

Topping-off technique for the protection of degenerative intervertebral disc / 中国组织工程研究

BACKGROUND:Topping-off technique can be used for fixation treatment through the combination of fusion and interspinous dynamic device, in order to prevent or slow down the adjacent lumbar segment degeneration. OBJECTIVE:To obverse the protective effect of Topping-off technique (posterior lumbar interbody fusion procedure combined with the fixation of dynamic interspinous device Coflex) for the degenerative intervertebral disc. METHODS:A total of 32 patients with degenerative lumbar diseases who had been treated with Topping-off technique were included in this study. The Oswestry disability index, the Japanese Orthopaedic Association scores, range of motion for Coflex implanted segment and during the relative signal intensity of the Coflex implanted segment in MRI image were recorded and calculated preoperatively and the entire fol ow-up period. RESULTS AND CONCLUSION:Al patients were fol owed-up for 20.6 months averagely. Up to the last fol ow-up, the Oswestry disability index and Japanese Orthopaedic Association scores were significantly improved when compared with those before treatment (P<0.001). There was no significant difference in the range of motion for Coflex implanted segment before and after treatment (P=0.19). The relative signal intensity of the Coflex implanted segment was significantly improved when compared with that before treatment (P<0.01). The clinical application of the Topping-off technique showed a protective effect on the intervertebral disc.

Expression of lentivirus-mediated neurotrophin-3 gene in Schwann cells / 中国组织工程研究

BACKGROUND:Neurotrophin-3 is found in the repair of spinal cord injury in the role of the strongest neurotrophic factor.It can effectively promote axonal regeneration through the glial scar tissue in repairing spinal cord injury.OBJECTIVE:To construct recombinant lentiviral vectors for gene delivery of homo sapiens neurotrophin-3(hNT3),and to investigate the expression of hNT3 gene in Schwann cells after transfection.DESIGN,TIME AND SETTING:Observational experiment was performed from June 2007 to March 2008 at the Central Laboratory of Changhai Hospital.MATERIALS:Bilateral sciatic nerves were harvested from 3-day-old Sprague Dawley rats for culture and identification of Schwann cells.Three-plasmid lentivirus systems:pGC-E1-EGFP,pHelper 1.0 and pHelper 2.0 were gained from Shanghai Chemical Technology Co.,Ltd.METHODS:pGC-E1-hNT3-EGFP plasmid was constructed by double restriction enzyme digestion and ligation,and then the plasmid was transformed into E.coli DH5?.Purified pGC-E1-hNT3-EGFP plasmids from the positive clones was confirmed by PCR and sequencing.293T cells were cotransfected with lentiviral vector pGC-E1-hNT3-EGFP,pHelper 1.0 and pHelper 2.0 by Lipofectamine 2000 to produce lentivirus.2 mL recombinant virus complete culture solution was added according to multiplicity of infection=1,4,8,10,12.The titer of virus was tested according to the expression level of enhanced green fluorescent protein.The control groups were Schwann cells and Schwann cells transfected by no-loaded lentivirus.MAIN OUTCOME MEASURES:The lentiviruses were transduced to Schwann cells,and the transfection efficiency was examined by flow cytometry,the overexpression of hNT3 was determined by Real-time PCR and Western blotting.RESULTS:The exogenous gene sequence of the recombinant hNT3 was completely in accordance with that of its open reading frame in GeneBank.The titer of concentrated virus was 5?107 TU/L.After recombinant LV-hNT3 infection,Schwann cells gave off strikingly bright green fluorescence,and the transfection efficiency amounted to 85%(multiplicity of infection=10).Real-time RCR test showed that the hNT3 mRNA were highly expressed in hNT3-Schwann cells,while did not express in the control group.Western blotting showed the hNT3 expression in Schwann cells.CONCLUSION:Construction of hNT3 gene lentiviral vector can transfect Schwann cells leading to an efficient overexpression of hNT3.