Fisetin orchestrates neuroinflammation resolution and facilitates spinal cord injury recovery through enhanced autophagy in pro-inflammatory glial cells.

BACKGROUND: Neuroinflammation, a critical component of the secondary injury cascade post-spinal cord injury, involves the activation of pro-inflammatory cells and release of inflammatory mediators. Resolution of neuroinflammation is closely linked to cellular autophagy. This study investigates the potential of Fisetin, a natural anti-inflammatory compound, to ameliorate neuroinflammation and confer spinal cord injury protection through the regulation of autophagy in pro-inflammatory cells. METHODS: Utilizing a rat T10 spinal cord injury model with distinct treatment groups (Sham, Fisetin-treated, and Fisetin combined with autophagy inhibitor), alongside in vitro models involving lipopolysaccharide (LPS)-stimulated microglial cell activation and co-culture with neurons, we employed techniques such as transcriptomic sequencing, histological assessments (immunofluorescence staining, etc.), molecular analyses (PCR, WB, ELISA, etc.), and behavioral evaluations to discern differences in neuroinflammation, autophagy, neuronal apoptosis, and neurological function recovery. RESULTS: Fisetin significantly augmented autophagic activity in injured spinal cord tissue, crucially contributing to neurological function recovery in spinal cord-injured rats. Fisetin's autophagy-dependent effects were associated with a reduction in neuronal apoptosis at the injury site. The treatment reduced the population of CD68+ and iNOS+ cells, coupled with decreased pro-inflammatory cytokines IL-6 and TNF-α levels, through autophagy-dependent pathways. Fisetin pre-treatment attenuated LPS-induced pro-inflammatory polarization of microglial cells, with this protective effect partially blocked by autophagy inhibition. Fisetin-induced autophagy in the injured spinal cord and pro-inflammatory microglial cells was associated with significant activation of AMPK and inhibition of mTOR. CONCLUSION: Fisetin orchestrates enhanced autophagy in pro-inflammatory microglial cells through the AMPK-mTOR signaling pathway, thereby mitigating neuroinflammation and reducing the apoptotic effects of neuroinflammation on neurons. This mechanistic insight significantly contributes to the protection and recovery of neurological function following spinal cord injury, underscoring the vital nature of Fisetin as a potential therapeutic agent.

Tofacitinib Promotes Functional Recovery after Spinal Cord Injury by Regulating Microglial Polarization via JAK/STAT Signaling Pathway.

Background: The JAK/STAT signaling pathway is the main inflammatory signal transduction pathway, whether JAK/STAT contributes the pathology of SCI and targeting the pathway will alleviate SCI needs to be addressed. Here, we explored the therapeutic effect of pan-JAK inhibitor tofacitinib (TOF) on secondary injury after SCI and explained the underlying mechanisms. Methods: SCI model in rat was established to evaluate the therapeutic effects of TOF treatment in vivo. Histological and behavioral analyses were performed at different time points after SCI. In vitro, the effects of TOF on pro-inflammatory activation of primary microglia and BV2 cells were analyzed by western blot analysis, fluorescent staining, qPCR and flow cytometry. The neuroprotection of TOF was detected using a co-culture system with primary neurons and microglia. Results: TOF can effectively improve motor dysfunction caused by spinal cord injury in rats. TOF administration in the early stage of inflammation can effectively inhibit neuronal apoptosis and scar tissue formation, and promote the repair of axons and nerve fibers. Further studies have demonstrated that TOF suppresses inflammation caused by spinal cord injury by inhibiting the activation of microglia to pro-inflammatory phenotype in vivo and in vitro. Additionally, an interesting phenomenon is revealed in our results that TOF exhibits superior neuronal protection during inflammation in vitro. Conclusions: Our study showed that TOF could regulate microglial activation via JAK / STAT pathway and promote the recovery of motor function after SCI, which is of great significance for the immunotherapy of SCI.

Comparative study of halo-vest reduction and skull traction reduction in the treatment of cervical fracture dislocation in patients with ankylosing spondylitis.

Background: This study aimed to investigate the safety and efficacy of the halo-vest in the treatment of cervical fracture in patients with ankylosing spondylitis (AS) and kyphosis. Methods: From May 2017 to May 2021, 36 patients with cervical fractures with AS and thoracic kyphosis were included in this study. The patients with cervical spine fractures with AS underwent preoperative reduction by halo-vest or skull tractions. Instrumentation internal fixation and fusion surgery were then performed. The level of cervical fractures, the operative duration, blood loss, and treatment outcomes were investigated preoperatively and postoperatively. Results: A total of 25 cases were included in the halo-vest group and 11 cases were included in the skull tractions group. The intraoperative blood loss and the surgery duration were significantly less in the halo-vest group than in the skull traction group. A comparison of American Spinal Injury Association scores at admission and final follow-up showed that the neurological function of patients improved in both groups. All patients had reached solid bony fusion during the follow-up. Conclusion: This study presented a unique approach to use halo-vest treatment fixation of unstable cervical fracture in patients with AS. The patient should also have early surgical stabilization with a halo-vest to correct spinal deformity and avoid worsening of neurological status.

Inhibition of IL1R1 or CASP4 attenuates spinal cord injury through ameliorating NLRP3 inflammasome-induced pyroptosis.

Spinal cord injury (SCI) is a devastating trauma characterized by serious neuroinflammation and permanent neurological dysfunction. However, the molecular mechanism of SCI remains unclear, and few effective medical therapies are available at present. In this study, multiple bioinformatics methods were used to screen out novel targets for SCI, and the mechanism of these candidates during the progression of neuroinflammation as well as the therapeutic effects were both verified in a rat model of traumatic SCI. As a result, CASP4, IGSF6 and IL1R1 were identified as the potential diagnostic and therapeutic targets for SCI by computational analysis, which were enriched in NF-κB and IL6-JAK-STATA3 signaling pathways. In the injured spinal cord, these three signatures were up-regulated and closely correlated with NLRP3 inflammasome formation and gasdermin D (GSDMD) -induced pyroptosis. Intrathecal injection of inhibitors of IL1R1 or CASP4 improved the functional recovery of SCI rats and decreased the expression of these targets and inflammasome component proteins, such as NLRP3 and GSDMD. This treatment also inhibited the pp65 activation into the nucleus and apoptosis progression. In conclusion, our findings of the three targets shed new light on the pathogenesis of SCI, and the use of immunosuppressive agents targeting these proteins exerted anti-inflammatory effects against spinal cord inflammation by inhibiting NF-kB and NLRP3 inflammasome activation, thus blocking GSDMD -induced pyroptosis and immune activation.

Cervical Myelopathy Due to Idiopathic Retro-odontoid Pseudotumor.

OBJECTIVE: A retro-odontoid pseudotumor (ROP) is commonly associated with atlantoaxial instability or rheumatoid arthritis. However, ROP in the absence of atlantoaxial instability or rheumatoid arthritis, which is termed idiopathic ROP (IROP), is a rare condition. The pathomechanisms and optimal treatment strategies for IROP remain controversial. The aim of the present study was to evaluate the radiographic and clinical characteristics of IROP patients and to assess the efficiency of atlantoaxial/occipitocervical fusion on IROP regression. METHODS: Data from 5 patients diagnosed with IROP were retrospectively reviewed. Posterior atlantoaxial or occipitocervical fixation and fusion were performed in 4 patients and C1 posterior arch resection alone in 1 patient. The patients' features, surgical procedures, and complications were recorded. The retro-odontoid soft tissue thickness was measured on preoperative and postoperative magnetic resonance imaging to evaluate IROP regression. RESULTS: The mean follow-up time was 37 months. ROP regression was achieved in patients who received atlantoaxial/occipitocervical fusion, but not for the patient with C1 posterior resection alone. There were no observed neurovascular complications associated with surgery. CONCLUSIONS: IROP was related to a restricted range of motion of the subaxial spine. Upper cervical fixation is an optional treatment that produces IROP regression over time. By contrast, direct removal of the IROP is unnecessary.

Cervical spine fracture-dislocation in patients with ankylosing spondylitis and severe thoracic kyphosis: Application of halo vest before and during surgical management.

Cervical spine fracture-dislocation in patients with ankylosing spondylitis (AS) and severe thoracic kyphosis is extremely unstable. This study was performed to investigate the efficacy and safety of halo vest application before and during surgery for these patients. We retrospectively analyzed the case histories, operations, neurologic outcomes, follow-up data, and imaging records of 25 patients with AS and severe thoracic kyphosis who underwent surgical treatment of cervical fracture-dislocation in our department from 2008 to 2019. A halo vest was used to reduce and immobilize the fractured spinal column ends before and during surgery. The neurologic injury was evaluated using the American Spinal Injury Association (ASIA) impairment scale score, visual analog scale (VAS) score, and Japanese Orthopaedic Association (JOA) score before and after the operation. Twenty-two patients achieved closed anatomical reduction; two achieved successful reduction and one underwent failed reduction after halo vest application. No fracture site displacement occurred after movement into the prone position. No patients developed secondary neurological deterioration. The mean Cobb angle of thoracic kyphosis was 69.0° ± 12.3°. All patients underwent posterior or combined anterior-posterior surgery. The ASIA grade improved significantly (P < 0.01). The mean VAS and JOA scores also increased significantly after the operation (14.6 ± 3.0 vs. 10.4 ± 4.3 and 0.5 ± 0.6 vs. 4.6 ± 1.9, respectively; P < 0.01). One patient died 3 weeks after the operation. No other severe complications occurred. All patients had reached solid bony fusion by the 12-month follow-up. Use of a halo vest before and during the operation is safe and effective in patients with AS and severe thoracic kyphosis who develop cervical fracture-dislocation. This technique makes positioning, awake nasoendotracheal intubation, nursing, and the operation more convenient. It can also provide satisfactory reduction and rigid immobilization and prevent secondary neurologic deterioration.

Relative mRNA and protein stability of epigenetic regulators in musculoskeletal cell culture models.

Control of gene expression by epigenetic regulators is fundamental to tissue development and homeostasis. Loss-of-function (LOF) studies using siRNAs for epigenetic regulators require that RNA interference rapidly reduces the cellular levels of the corresponding mRNAs and/or proteins. The most abundant chromatin structural proteins (i.e., the core histones H2A, H2B, H3 and H4) have relatively long half-lives and do not turn over rapidly, although their mRNAs are labile. The question arises whether epigenetic regulatory enzymes (e.g., Ezh2) or proteins that interact with histones via selective modifications (e.g., Cbx1 to Cbx8, Brd4) are stable or unstable. Therefore, we performed classical α-amanitin and cycloheximide inhibition assays that block, respectively, mRNA transcription and protein translation in mouse MC3T3 osteoblasts, ATDC5 chondrocytes and C2C12 myoblasts. We find that mRNA levels of Cbx proteins and Ezh2 were significantly depleted after 24 hrs, while their corresponding proteins remained relatively stable. As positive control, the half-life of the labile cyclin D1 protein was found to be less than 1 hr. Our study suggests that histone code readers and writers are relatively stable chromatin-related proteins, which is consistent with their long-term activities in maintaining chromatin organization and phenotype identity. These findings have conceptual ramifications for the interpretation of RNAi experiments that reduce the mRNA but not protein levels of epiregulatory proteins. We propose that siRNAs for at least some epigenetic regulatory proteins may exert their biological effects by blocking translation and new protein synthesis rather than by decreasing pre-existing protein pools.

A new decompression technique for upper lumbar fracture with neurologic deficit-comparison with traditional open posterior surgery.

BACKGROUND: Surgery is usually recommended for thoracolumbar fracture with neurologic deficit. However, traditional open posterior approach requires massive paraspinal muscles stripping, and the canal decompression may be limited and incomplete. We aimed to investigate a new approach via the Wiltse approach and the Kambin's Triangle. METHODS: Twenty-one consecutive patients with traumatic upper lumbar fracture who received this new approach surgery between January 2015 and January 2016 constituted the new approach group. Twenty-nine patients received the traditional open posterior surgery between January 2014 and January 2015 were classified as the traditional posterior surgery group. Surgical informations including operative time, blood loss, drainage volume, hospitalization days were collected and compared among the two groups. The American Spinal Injury Association (ASIA) impairment scale and Visual Analog Score (VAS) were evaluated preoperatively, postoperatively and at 12 months follow-up. RESULTS: Patients in the new approach group had fewer operation time (128.3 ± 25.1 vs 151 ± 32.2 min, P = 0.01), less blood loss (243.8 ± 135.5 vs 437.8 ± 224.9 ml, P = 0.001) and drainage volume (70.7 ± 57.2 vs 271.7 ± 95.5 ml, P < 0.001), as well as shorter hospitalization stay than the traditional posterior surgery group (6.6 ± 1.8 vs 8.5 ± 2.4 d, P = 0.004). Similar neurologic recovery according to ASIA grade was achieved in both groups (Recovery index: 0.90 ± 0.53 vs 0.86 ± 0.51, P = 0.778). While the pain level was significantly lower in the new approach group postoperatively (2.6 ± 0.7 vs 3.5 ± 0.9, P < 0.001) and at 12 months follow-up (1.4 ± 0.9 vs 2.4 ± 0.8, P < 0.001). CONCLUSION: The present new approach was successfully applied in the treatment of upper lumbar fracture with neurologic deficit. It can reduce iatrogenic trauma and achieve similar or better outcomes compared to the traditional posterior surgery.

Surgical Treatment for Odontoid Fractures in Patients with Long-Standing Ankylosing Spondylitis: A Report of 3 Cases and Review of the Literature.

BACKGROUND: Ankylosing spondylitis (AS) is classified as a chronic inflammatory seronegative rheumatic arthritis. Patients with AS are more likely to sustain a fracture of the cervical spine compared with the general population. Most fractures occur in the lower cervical spine and manifest at the level of the intervertebral disc. There have been few reports about the surgical treatment for upper cervical spine fractures in patients with AS, especially odontoid fractures. We present 3 cases of odontoid fracture in patients with long-standing AS. METHODS: Odontoid fracture with atlantoaxial displacement was identified on radiologic imaging in 3 patients. In 1 patient, fracture was a missed diagnosis after initial trauma, and the fracture and displacement were discovered 3 months later owing to aggravation of symptoms. Posterior occipitocervical fusion with iliac autograft was performed under general anesthesia in all cases. RESULTS: All 3 patients recovered postoperatively without any complications related to surgery. Cervical radiographs obtained at 12-month follow-up demonstrated healed fracture and replacement of the atlantoaxial joint. CONCLUSIONS: Odontoid fracture with atlantoaxial dislocation in patients with long-standing AS is uncommon. Clinicians must be cautious in assessing such patients with any episode of trauma. Computed tomography and magnetic resonance imaging can be helpful in demonstrating occult odontoid fractures. Posterior occipitocervical fusion with internal fixation may benefit these patients, although at the cost of sacrificing the last motion segment.

Lumbosacral Transitional Vertebra: Possible Role in the Pathogenesis of Adolescent Lumbar Disc Herniation.

OBJECTIVE: To investigate the role of lumbosacral transitional vertebra (LSTV) in the pathogenesis of adolescent lumbar disc herniation (ALDH) and the association between LSTV type and the herniation level of ALDH. METHODS: This study was a retrospective case-control analysis of roentgenographic images. All adolescent patients who received surgical treatment for L4/5 or L5/S1 single level lumbar disc herniation in our department from 2010 to 2015 were eligible for the ALDH group. All adolescent patients admitted to our hospital during the same period and who had ever undergone a plain anteroposterior radiologic examination of the abdomen and met the inclusion criteria that ensured the absence of any spinal disorders were selected into the control group. The anteroposterior lumbar or abdomen roentgenograms were collected to identify the LSTV. The incidence of LSTV in the ALDH group and the control group were compared. Among the ALDH group, the association between LSTV type (sacralization or lumbarization) and the herniation level of ALDH were evaluated. RESULTS: A total of 80 adolescent patients were included in the ALDH group and 92 asymptomatic adolescents were included in the control group. LSTV was found in 24 patients (30%) in ALDH group compared with 7 patients (7.6%) in the control group (P < 0.001; odds ratio, 5.2; 95% confidence interval 2.1, 12.9). Among the adolescent patients with sacralization, the L4/5 disc herniation was significantly more common than L5/S1 (81.3% vs. 18.7%; P = 0.019). CONCLUSIONS: The LSTV is associated with LDH in adolescents and the sacralization of L5 may contribute to the L4/5 disc herniation in adolescent patients.

Multifidus Degeneration, A New Risk Factor for Lumbar Spinal Stenosis: A Case-Control Study.

OBJECTIVES: To analyze whether multifidus degeneration has a relationship with degenerative lumbar spinal stenosis (LSS). MATERIALS AND METHODS: Clinical data of 40 patients with LSS were analyzed retrospectively. Moreover, 40 healthy people were selected as controls. Subjects of both groups underwent a 1.5-T lumbar spinal magnetic resonance imaging scan in our hospital, and then the multifidus muscularity, fatty infiltration ratio, and bilateral asymmetry at L4/5 level on magnetic resonance imaging were measured with ImageJ software to analyze and compare the multifidus parameters between the 2 groups. RESULTS: Compared with the control group, the multifidus muscularity was lower, fatty infiltration ratio was greater, and muscle asymmetry was more significant at the L4/5 level in patients with LSS, and the difference between the 2 groups was statistically significant. CONCLUSIONS: Multifidus degeneration, including reduced volume, increased fatty infiltration, and bilateral muscle asymmetry, has an association with LSS.

A Validated Finite Element Analysis of Facet Joint Stress in Degenerative Lumbar Scoliosis.

OBJECTIVE: To develop modified finite element models to simulate degenerative lumbar scoliosis (DLS) based on the normal lumbar spine model and to investigate the facet joint force of the DLS. METHODS: A 3-dimensional finite element model of a normal lumbar spine was modified to simulate 3 different Cobb angles conditions (12.3°, 22.2°, and 31.8°). The stresses on the facet joint were calculated on both sides (right and left) of the each vertebra. Changes of stress and asymmetry in contact forces between facet joints in the development of DLS were quantitatively analyzed to better understand the development of DLS and the biomechanical forming mechanism. RESULTS: The results show that asymmetric responses of the facet joint forces exist in various postures and that such effect is amplified with larger curve. When the Cobb angle was smaller, the convex side of the facet joints suffered larger force. When the Cobb angle was larger than 20°, the concave side of the facet joints suffered larger force. In the axial-rotation cases, the facet joint compression is less often located on the ipsilateral side than the contralateral side at the same level. CONCLUSIONS: With the asymmetric loading, facet joints compressive deformation appears on the concave side, and it decreases in the effect of the facet joints to limit the vertebral rotation and listhesis. Asymmetric loading on facet joint contact forces accelerates asymmetry in the lumbar spine.

Standalone Anterior Cervical Discectomy and Fusion Versus Combination with Foraminotomy for the Treatment of Cervical Spondylotic Radiculopathy Secondary to Bony Foraminal Stenosis.

OBJECTIVE: To compare the results of anterior cervical discectomy and fusion (ACDF) combined with anterior cervical foraminotomy (ACF) and standalone ACDF for the treatment of cervical spondylotic radiculopathy (CSR). METHODS: The data of 24 consecutive patients who underwent ACDF combined with ACF for significant bony foraminal stenosis were reviewed. The clinical outcomes, including visual analog scale (VAS) scores for neck pain and arm pain and Neck Disability Index, were evaluated by questionnaires. Radiologic outcomes as manifested by C2-7 angle and surgical segmental angle were recorded. The outcomes were compared with outcomes of standalone ACDF for CSR secondary to posterolateral spurs. RESULTS: At the final follow-up evaluation, all patients obtained bone fusion. No patient developed adjacent segment disease. Operative time was longer and blood loss was more in the ACDF combined with ACF group than in the ACDF group (all P < 0.05). However, in both groups, the neck VAS score, arm VAS score, and Neck Disability Index were significantly reduced postoperatively (all P < 0.05). The segmental curve and C2-7 lordosis were significantly improved postoperatively (all P < 0.05). There was no significant difference between the 2 groups in clinical and radiologic outcomes (P > 0.05). CONCLUSIONS: For CSR with foraminal stenosis secondary to significant bony pathology that cannot be managed with standalone ACDF, ACDF combined with ACF is an effective and safe treatment strategy.