Dysregulated MiR-3150a-3p Promotes Lumbar Intervertebral Disc Degeneration by Targeting Aggrecan.

BACKGROUND/AIMS: Low back pain has become one of the most common musculoskeletal diseases in the world. Studies have shown that intervertebral disc degeneration (IDD) is an important factor leading to low back pain, but the mechanisms underlying IDD remain largely unknown. Research over the past decade has suggested critical roles for microRNAs (miRNAs) in natural growth and disease progression. However, it remains poorly understood whether circular RNAs participate in IDD. METHODS: Clinical IDD samples were collected from 20 patients who underwent discectomy. Weighted gene co-expression network analysis was used to identify the co-expression miRNA network modules (highly co-expressed clusters of miRNAs) that were associated with IDD grade. RESULTS: miR-3150a-3p was the most significantly up-regulated miRNA in module "Blue." Notably, aggrecan (ACAN) was identified as a direct target gene of miR-3150a-3p and ACAN expression was regulated by miR-3150a-3p. Overexpression of miR-3150a-3p decreased ACAN expression in nucleus pulposus cells, whereas inhibition of miR-3150a-3p increased ACAN expression. In addition, ACAN expression was negatively correlated with IDD grade. CONCLUSION: Our study suggests that the reduction of ACAN expression induced by the upregulation of miR-3150a-3p might participate in the development of IDD.

Multifunctional biomimetic spinal cord: New approach to repair spinal cord injuries.

The incidence of spinal cord injury (SCI) has been gradually increasing, and the treatment has troubled the medical field all the time. Primary and secondary injuries ultimately lead to nerve impulse conduction block. Microglia and astrocytes excessively accumulate and proliferate to form the glial scar. At present, to reduce the effect of glial scar on nerve regeneration is a hot spot in the research on the treatment of SCI. According to the preliminary experiments, we would like to provide a new bionic spinal cord to reduce the negative effect of glial scar on nerve regeneration. In this hypothesis we designed a new scaffold that combine the common advantage of acellular scaffold of spinal cord and thermosensitive gel, which could continue to release exogenous basic fibroblast growth factor (BFGF) in the spinal lesion area on the basis of BFGF modified thermosensitive gel. Meanwhile, the porosity, pore size and material of the gray matter and white matter regions were distinguished by an isolation layer, so as to induce the directed differentiation of cells into the defect site and promote regeneration of spinal cord tissue.

The Impact of Diabetes Mellitus on Patients Undergoing Cervical Spondylotic Myelopathy: A Meta-Analysis.

AIMS: We conducted a meta-analysis of eligible studies to compare the surgical outcomes between diabetic patients and non-diabetic patients who have undergone cervical spondylotic myelopathy (CSM). METHODS: A systematic literature search of PubMed, Embase, and Web of Science (up to February 10, 2016) was conducted. Eligible studies were case-control or cohort studies that compared the outcomes of cervical surgery between diabetic patients and non-diabetic patients. Weighted mean differences, risk ratios, and 95% CIs were calculated and heterogeneity was assessed with Cochrane Q chi-square test and I2 statistic. RESULTS: Six studies with a total of 38,680 patients were included in this meta-analysis. Pooled estimates showed that diabetic patients had significantly lower Japanese Orthopaedic Association (JOA) score change between pre- and post operation, and recovery rate than patients without diabetes. Moreover, diabetic patients had significantly increased risk of operative wound, epidural/wound hematoma, chronic lung disease, and cardiac complication. Other postoperative complications, including cerebrospinal fluid leakage and C5 radiculopathy, were not significantly different between the 2 groups. CONCLUSION: Diabetes mellitus decreased the JOA score change and recovery rate, as well as increased the risk of postoperative complications in patients undergoing CSM. Controlling diabetes mellitus before cervical spine surgery may lead to better outcomes.

New approach to treating spinal cord injury using PEG-TAT-modified, cyclosporine-A-loaded PLGA/polymeric liposomes.

Cyclosporine-A (CsA) is an immunosuppressant agent that has shown effectiveness as a neuroprotective drug; however, it does not readily cross the blood-spinal cord barrier (BSCB), which constrains the clinical applications of CsA for the treatment of spinal cord injury (SCI). Our group recently tested the ability of novel polyethylene glycol (PEG)-transactivating-transduction protein (TAT)-modified CsA-loaded cationic multifunctional polymeric liposome-poly(lactic-co-glycolic acid) (PLGA) core/shell nanoparticles (PLGA/CsA NPs) to transport and deliver CsA across the BSCB to treat SCI. The PLGA/CsA NPs were successfully constructed. In vitro drug release studies have demonstrated that the sustained release of CsA from PLGA/CsA NPs occurs over ∼25 h. The in vivo study presented here showed that injured animals that received PLGA/CsA NPs through the tail vein, exhibited a significant up-regulation of growth-associated protein-43 (GAP-43) expression and an increased number of GAP-43-stained neurons compared with animals that received CsA or the vehicle alone. The improvement in neurological function was also evaluated by the Basso-Beattie-Bresnahan (BBB) open-field test. Moreover, fluorescein isothiocyanate (FITC)-attached PLGA/CsA NPs were successfully aggregated in the intact spinal cord 4 h after injection. Our data suggest that PLGA/CsA NPs have the potential for use as a new treatment method for SCI.

Photodynamic Therapy Mediated by Upconversion Nanoparticles to Reduce Glial Scar Formation and Promote Hindlimb Functional Recovery After Spinal Cord Injury in Rats.

Glial scar formation is one of the major consequences of spinal cord injury, which prevents the regenerated axons passing the injured area and forming effective synaptic connection. In this paper, we used photodynamic therapy (PDT), which was mediated by the upconversion nanoparticles coated with polyethylene glycol (PEG) and photosensitizer (UCNPs-PEGM540), to reduce the glial scar formation after spinal cord injury. The in vitro experimental results indicated that cultured astrocytes could be killed by using upconversion nanoparticles after excitation with near infrared light. By transplanting UCNPs-PEG-M540 into the margin area of injured epicenter of spinal cord, the recovery of rat's hindlimb function was evaluated in Basso, Beattie, Bresnahan locomotor rating scale, respectively. The improvement in microenvironment of the injured spinal cord was also evaluated by glial fibrillary acidic protein staining, neurofiliment staining, biotinylated dextran amine anterograde tracing and western blotting. Our results demonstrated that more regenerative axons of corticospinal tract were found to surround and pass through the injured cavity to the caudal cord with transplanting UCNPs-PEG-M540 into the injured spinal cord. In conclusion, our results strongly suggested that upconversion nanoparticles combined with photodynamic therapy can promote functional recovery in rats' hindlimbs by reducing the formation of glial scar and promoting remyelination of injured axons.

Transplantation of autologous activated Schwann cells in the treatment of spinal cord injury: six cases, more than five years of follow-up.

Schwann cells (SCs) are the main glial cells of the peripheral nervous system, which can promote neural regeneration. Grafting of autologous SCs is one of the well-established and commonly performed procedures for peripheral nerve repair. With the aim to improve the clinical condition of patients with spinal cord injury (SCI), a program of grafting autologous activated Schwann cells (AASCs), as well as a series of appropriate neurorehabilitation programs, was employed to achieve the best therapeutic effects. We selected six patients who had a history of SCI before transplantation. At first, AASCs were obtained by prior ligation of sural nerve and subsequently isolated, cultured, and purified in vitro. Then the patients accepted an operation of laminectomy and cell transplantation, and no severe adverse event was observed in any of these patients. Motor and sensitive improvements were evaluated by means of American Spinal Injury Association (ASIA) grading and Functional Independence Measure (FIM); bladder and urethral function were determined by clinical and urodynamic examination; somatosensory evoked potentials (SSEPs) and motor evoked potentials (MEPs) were used to further confirm the functional recovery following transplantation. The patients were followed up for more than 5 years. All of the patients showed some signs of improvement in autonomic, motor, and sensory function. So we concluded that AASC transplantation might be feasible, safe, and effective to promote neurorestoration of SCI patients.

Combination of activated Schwann cells with bone mesenchymal stem cells: the best cell strategy for repair after spinal cord injury in rats.

AIM: We aim to explore the repair effect of combined cell therapy using activated Schwann cells (ASCs) and bone mesenchymal stem cells (BMSCs) in traumatic spinal cord injury (SCI) in rats. MATERIALS & METHODS: ASCs and BMSCs were used for combined transplantation to treat acute SCI in rats, both of which can be obtained from SCI patients. ASCs were obtained by prior ligation of saphenous nerve and BMSCs by flush of the marrow cavity with Dulbecco's modified Eagle's medium solution. Our experiment in vitro confirmed that ASCs promoted BMSCs to differentiate into mature neural cells. It also indicates that BMSCs hold the potential to repair CNS injury. ASCs and BMSCs were co-transplanted into the injured epicenter of spinal cord made by the New York University (NYU) impactor machine using a 10 g × 50 mm drop weight. Complete ASCs, BMSCs and Dulbecco's modified Eagle's medium were also transplanted in rats with SCI as a control. Recovery of rat's hindlimb function was serially evaluated by Basso, Beattie, Bresnahan locomotor rating scale and footprint analysis. Changes of neurological potential were recorded by nerve electrophysiologic test. Improvement in the microenvironment of the injured spinal cord was evaluated by hematoxylin and eosin staining, glial fibrillary acidic protein staining, biotinylated dextran amine anterograde tracing and electron microscopy. RESULTS: Using biotinylated dextran amine anterograde tracing, we demonstrated that there were more regenerative axons of corticospinal tract surrounding and passing through the injured cavity to the caudal cord in the ASC-BMSC co-graft group than those in the other three groups, and we also confirmed this further by quantitative analysis. Immunostaining for glial fibrillary acidic protein showed the smallest population of astrocytes in the injury epicenter in the ASC-BMSC group compared with the other three groups. Relatively complete myelin sheaths and organelles were found in the ASC-BMSC group compared with the other three groups under electron microscopy. CONCLUSION: Effective co-transplantation of ASCs and BMSCs promotes functional recovery in rats' hindlimbs and reduces the formation of glial scar, and remyelinates the injured axons as compared with the other three groups. This conclusion was also supported by the observation of immunohistochemistry staining and electron microscopy, suggesting the possible clinical application for the treatment of spinal injury.

Novel multifunctional polyethylene glycol-transactivating-transduction protein-modified liposomes cross the blood-spinal cord barrier after spinal cord injury.

The blood-spinal cord barrier (BSCB) prevents many macromolecular agents from passing through to reach sites of injury in the spinal cord. This study evaluated the ability of a novel multifunctional liposome modified with polyethylene glycol (PEG) and transactivating-transduction protein (TAT) containing an iron core to cross the BSCB using a rat model of spinal cord injury. Rats were examined daily for a period of three days after spinal cord injury and injection of either the multifunctional modified liposome or control formulations using a 3.0 T magnetic resonance imaging spectrometer. A low signal was observed in the T2-weighted images. Prussian blue staining and flame atomic absorption spectrophotometry revealed that significantly more iron accumulated around the lesion site in the experimental group than the control groups (P < 0.05). The findings from this study suggest that this multifunctional liposome carrier can cross the BSCB to accumulate around the lesion site.

Intraspinal cord graft of autologous activated Schwann cells efficiently promotes axonal regeneration and functional recovery after rat's spinal cord injury.

Basic research in spinal cord injury (SCI) has made great strides in recent years, and some new insights and strategies have been applied in promoting effective axonal regrowth and sprouting. However, a relatively safe and efficient transplantation technique remains undetermined. This study, therefore, was aimed to address a question of how to graft Schwann cells to achieve the best possible therapeutic effects. To clarify the issue, the rats were subjected to spinal cord injury at T10. Autologous activated Schwann cells (AASCs) were obtained by prior ligation of saphenous nerve and subsequently isolated and purified in vitro and then grafted into spinal cord-injured rats via three different routes (group I: intravenous, group II: intrathecal and group III: intraspinal cord). Neurologic function was serially evaluated by Basso, Beattie, Bresnahan locomotor rating scale and footprint analysis. We also evaluated the migration of the transplanted cells at 2 weeks after transplantation. Using biotinylated dextran amine (BDA) anterograde tracing, we demonstrated that more regenerative axons of corticospinal tract (CST) surrounding the injured cavity in group III than those in the other two groups, and we also confirmed it further by quantitative analysis. The microenvironment surrounding the injured spinal cord has been improved to the greatest extent in group III, as determined by immunohistological staining. Relatively complete myelin sheaths and more neurofilaments in axons were found in groups II and III than those in group I under electron microscopy. The results showed that intraspinal cord injection of AASCs promoted recovery of hindlimb locomotor function of injured rats more efficiently than the other grafting routes. In addition, intact myelin sheaths and sufficient neurofilaments in axons were not adequate for full functional recovery after SCI, suggesting that reestablishment of normal synaptic connection is indispensable. The findings in this study strongly suggest that transplantation of AASCs directly into the spinal cord may be one of the promising candidates for potential scaffold for injured spinal cord, and such strategy of transplantation of AASCs could be hopeful to treat patients with SCI.

Regeneration of spinal cord with cell and gene therapy.

OBJECTIVE: Transplantation of fetal spinal cord cells (FSCC) can promote regeneration of injured spinal cord, while Schwann cells (SC) and some growth factors have a similar effect. However, the synergistic effects and optimal combination of these modalities have not yet been evaluated. In the current study, the efficiency of cell therapy of FSCC and/or SC, with/without growth factors (nerve growth factor [NGF] and brain-derived neurotrophic factor [BDNF]) was examined, with the aim of establishing an optimized protocol for spinal cord injury. METHODS: One hundred and twenty adult rats were randomly divided into six groups with 20 rats in each group. One week after the thoracic spinal cord injury model had been created, the rats were treated with different therapeutic modalities: Dulbecco's modified Eagles medium (DMEM) in Group I, FSCC in Group II, FSCC plus SC in Group III, FSCC plus SC over-expressing NGF in Group IV, FSCC plus SC over-expressing BDNF in Group V, and FSCC plus SC over-expressing both NGF and BDNF in Group VI. Subsequently, the rats were subjected to behavioral tests once a week after injury, while histology, immunohistochemistry and electron microscopy were performed at one and three month post-operation. RESULTS: Both SC and FSCC promoted regeneration of spinal cord injury when used separately, while a combination of the two types of cell resulted in better recovery than either alone. Both growth factors (NGF and BDNF) enhanced the outcomes of cell therapy, while synergistic effects meant that a combination of each individual component (group VI) achieved the best results according to locomotion scale, histology and immunoreactivity in the injured cords. CONCLUSION: SC, NGF and BDNF can enhance the outcome of FSCC therapy, while the combination of FSC with SC, NGF and BDNF is possibly the optimal protocol for clinical treatment of acute spinal cord injury.