Current and emerging treatment options for spinal cord ischemia

SARS-CoV-2 and spinal cord ischemia: a systematic review on clinical presentations, diagnosis, treatment, and outcomes

BACKGROUND CONTEXT

Spinal cord ischemia is a rare but ominous clinical situation with high levels of disability. There are emerging reports on COVID-19 and spinal cord ischemic events.

PURPOSE

To investigate the cardinal manifestations of SARS-CoV-2 associated spinal cord ischemia, review treatment paradigms, and follow outcomes.

STUDY DESIGN

A systematic review.

METHODS

The current study was conducted under Preferred Reporting Items for Systematic Reviews and Meta-analysis (PRISMA) guidelines. The authors searched PubMed, Scopus, Web of Science, and Google Scholar for studies published up to February 12, 2023, on spinal cord ischemia and SARS-CoV-2 infection. Data on patient demographics, study methods, medical records, interventions, and outcomes were extracted from eligible articles. For each data set, the authors performed pooled estimates examining 3 factors of interest, which were (1) predisposing factors (2) treatment regimens, and (3) neurological rehabilitation outcomes. Neurological status was reported as the American Spinal Injury Association (ASIA) impairment scale reported by data sets.

RESULTS

Six data sets were identified. The mean age of the study population was 50 years old, with 66.6% male predominance. Sixty-six percent of the patients had severe COVID-19. Five data sets reported preexisting coagulopathy. ASIA A and B were the most prevalent primary neurological status (80%). The mean interval between COVID-19 and the first neurological deficit was 13 days. Anterior spinal artery lesions were the most prevalent ischemic pattern. The most common treatment regimens were heparin and steroid therapy. Physical rehabilitation showed poor functional outcomes.

CONCLUSIONS

SARS-CoV-2 is associated with spinal cord ischemia through multiple neuropathological mechanisms. Proper coagulation profile control and aggressive rehabilitation may play a promising role in the prevention and recovery of spinal cord infarction in SARS-CoV-2 patients.

Spontaneous spinal cord infarction: a practical approach

Spontaneous spinal cord infarction is significantly less common than cerebrovascular disease. Because of the tight anatomical distribution of pathways in the cord, small spinal cord infarcts usually give more obvious symptoms and signs than similar lesions in the brain. Large epidemiological stroke studies have generally not included spinal cord stroke and so the incidence of vascular syndromes in the spinal cord is unknown. Management and prevention strategies for spontaneous spinal cord infarcts stem from small case series and case reports. Patient outcomes from spinal cord infarction are better with prompt recognition, timely management and prevention of associated medical complications arising from paraplegia, tetraplegia, neurogenic bladder and bowel dysfunction. The process of rehabilitation following spinal cord infarction is an evolving area.

Recovery of neurological function following type B aortic dissection complicated by paraplegia

A woman in her 50s presented with uncontrolled hypertension, chest/back pain, paraplegia, right lower limb ischaemia and acute kidney injury. A CT angiogram demonstrated a type B aortic dissection originating distal to the left subclavian artery to bilateral common iliac arteries complicated by occlusion of the right renal artery and right common iliac artery. She was started on intravenous antihypertensive therapy and transferred to our institution for emergent thoracic endovascular aortic repair. Due to bleeding risk from coagulopathy, a spinal drain was not placed immediately post-operatively but instead was inserted after 24 hours while maintaining a mean arterial pressure of 80-100 mm Hg. Postoperatively, her right lower extremity perfusion was re-established, and her renal function recovered following temporary dialysis. At discharge on postoperative day 13, she regained full neurological function.

Neuronal Pre- and Postconditioning via Toll-like Receptor 3 Agonist or Extracorporeal Shock Wave Therapy as New Treatment Strategies for Spinal Cord Ischemia: An In Vitro Study

Spinal cord ischemia (SCI) is a devastating and unpredictable complication of thoracoabdominal aortic repair. Postischemic Toll-like receptor 3 (TLR3) activation through either direct agonists or shock wave therapy (SWT) has been previously shown to ameliorate damage in SCI models. Whether the same applies for pre- or postconditioning remains unclear. In a model of cultured SHSY-5Y cells, preconditioning with either poly(I:C), a TLR3 agonist, or SWT was performed before induction of hypoxia, whereas postconditioning treatment was performed after termination of hypoxia. We measured cytokine expression via RT-PCR and utilized Western blot analysis for the analysis of signaling and apoptosis. TLR3 activation via poly(I:C) significantly reduced apoptotic markers in both pre- and postconditioning, the former yielding more favorable results through an additional suppression of TLR4 and its downstream signaling. On the contrary, SWT showed slightly more favorable effects in the setting of postconditioning with significantly reduced markers of apoptosis. Pre- and post-ischemic direct TLR3 activation as well as post-ischemic SWT can decrease apoptosis and proinflammatory cytokine expression significantly in vitro and might therefore pose possible new treatment strategies for ischemic spinal cord injury.

Spontaneous spinal cord infarction in Austria: a two-center comparative study

Background:

Spinal cord infarction (SCI) is a neurological emergency associated with high rates of persistent neurological deficits. Knowledge about this rare but potentially treatable condition needs to be expanded.

Objective:

To describe the characteristics of spontaneous SCI in a large retrospective series of patients treated at two tertiary care centers in Austria.

Methods:

We performed a descriptive and comparative analysis of spontaneous SCI treated at the University Hospitals of Salzburg and Graz between the years 2000 and 2020. The analysis included pre- and in-hospital procedures, clinical presentation, etiology, diagnostic certainty, reperfusion therapy, and functional outcome at discharge.

Results:

We identified 88 cases, 61% were ascertained in the second half of the study period. The median age was 65.5 years [interquartile range (IQR) = 56–74], 51.1% were women. Anterior spinal artery infarction was the predominant syndrome (82.9%). Demographics, vascular comorbidities, and clinical presentation did not differ between the centers. The most frequent etiology and level of diagnostic certainty were distinct, with atherosclerosis (50%) and definite SCI (42%), and unknown (52.5%) and probable SCI (60%) as front runners in Salzburg and Graz, respectively. Patients arrived after a median of 258.5 min (IQR = 110–528) at the emergency room. The first magnetic resonance imaging (MRI) of the spinal cord was performed after a median of 148 min (IQR = 90–312) from admission and was diagnostic for SCI in 45%. Two patients received intravenous thrombolysis (2.2%). The outcome was poor in 37/77 (48%).

Conclusion:

Demographics, clinical syndromes, and quality benchmarks for spontaneous SCI were consistent at two Austrian tertiary care centers. Our findings provide the foundation for establishing standards for pre- and in-hospital care to improve outcomes.

MRI T2WI High Signal Is a Risk Factor for Perioperative Complications in Patients with Cervical Spondylosis with Spinal Cord Compression: A Propensity Matching Score Analysis

Objective

The purpose of this study was to compare the perioperative complications and clinical efficacy of patients with cervical spondylosis with spinal cord compression (CSWSCC) with or without MRI T2WIHS (T2-weighted image high signal) by means of propensity matching score grouping.

Methods

We analyzed a single-center data of 913 surgical patients with CSWSCC by propensity matching score in this study, of which 326 patients had preoperative cervical MRI T2WIHS. The patient's general condition and perioperative indicators were collected. The MRI T2WIHS and normal groups were paired 1 : 1 to eliminate selection bias by propensity matching score. Finally, a total of 312 pairs were matched successfully. The results of perioperative complications and other outcome variables were compared between the two groups by Cox function analysis.

Results

The postoperative blood loss, operation time, blood transfusion volume, systemic complications, local complications, volume of drainage, abnormal use of antibiotic, length of hospital stay, and JOA (Japanese Orthopaedic Association) improvement rate were analyzed. As the only complication with significant statistical difference, the incidence of IRI (ischemia-reperfusion injury) in patients with MRI T2WIHS was significantly higher. The length of hospital stay was more significantly increased in patients with MRI T2WIHS; on the contrary, the JOA improvement rate decreased significantly.

Conclusion

This study confirmed that there was no significant difference in the incidence of perioperative complications in CSWSCC patients with or without MRI T2WIHS, except for the IRI. Moreover, the JOA improvement rate of patients without MRI T2WIHS was significantly better, with the length of hospital stay reduced.

Protective Effect of Mild Hypothermia on Spinal Cord Ischemia-Induced Delayed Paralysis and Spinal Cord Injury

To explore the mechanism regarding the regulation of spinal cord ischemia (SCI) in rats by mild hypothermia. A SCI rat model was established through aorta occlusion, and in some cases, the rats were intervened with mild hypothermia, after which motor function, microglia activation, and M1/M2 polarization in rats were measured. Also, the expression of inflammatory cytokines (IL-1β, IL-6 and TNF-α) and neuronal apoptosis were examined. Lipopolysaccharide (LPS)-induced M1 microglia and IL-4-induced M2 microglia were intrathecally injected into rats to evaluate the effect of microglial polarization on SCI. In in vitro experiments, primary microglial cells were treated under hypothermic condition, in which M1/M2 polarization and microglia apoptosis, the levels of iNOS, CD86, CD206, Arg-1 and inflammatory cytokines were assessed. Western blot analysis detected the activation of the TLR4/NF-κB pathway to investigate the role of this pathway in M1/M2 polarization. SCI treatment impaired motor function, induced higher M1 microglia proportion, and increased the levels of pro-inflammatory cytokines in rats, and mild hypothermic treatment attenuated these trends. Moreover, injection of M1 microglia increased M1 microglia proportion and increased the levels of pro-inflammatory cytokines, while injection of M2 microglia induced the reverse results, i.e. decreased M1 microglia proportion and reduced pro-inflammatory cytokine levels. In LPS-induced microglial cells, mild hypothermia treatment increased M2 microglia proportion and decreased pro-inflammatory cytokine levels, relative to normothermia. Mild hypothermia inactivated the TLR4/NF-κB pathway in LPS-treated microglia. TLR4 overexpression reversed the function of mild hypothermia in LPS-stimulated microglia, and under normal condition, TLR4/NF-κB pathway suppressed microglial M2 polarization. Mild hypothermia inhibits TLR4/NF-κB pathway and promotes microglial M2 polarization, thus attenuating SCI-induced injury and inflammation.

Acute spinal cord infarction after multilevel en bloc corpectomy: a case report and literature review

Spinal cord infarction (SCI) is a catastrophic neurologic deficit following spine surgery. Because of the opposite management regimens used for SCI and acute epidural hematoma, accurate diagnosis of SCI is of great importance to maximally reserve neurologic functions and improve outcomes. A 21-year-old man developed acute paralysis and sensory deficits of the bilateral lower limbs shortly after undergoing two-stage combined posterior and anterior multilevel en bloc corpectomy. An emergency second-look surgery revealed wide-spectrum blackness of the thecal sac with no signs of an epidural hematoma. The patient underwent anticoagulation therapy, ventilation support, microcirculation perfusion, and fluid optimization. He regained an ambulatory status without other severe complications. Upon discharge, his muscle strength had returned to grade 4 and his Eastern Cooperative Oncology Group performance score had decreased to 0. At the final 48-month follow-up, the implants were in good position without local recurrence, and the patient was able to lead an independent life and work in his full capacity. An epidural hematoma did not appear to be the cause of SCI after spinal tumor surgery in this case; however, SCI was a possible reason for the acute paralysis. Anticoagulation treatment with adjuvant therapies may be an effective option in managing SCI.

Ecto-5'-nucleotidase (CD73) inhibits dorsal root ganglion neuronal apoptosis by promoting the Ado/cAMP/PKA/CREB pathway

Spinal cord injury (SCI) is a serious affliction that can lead to insufficient blood supply to the spinal cord, resulting in nutrient and energy deficiency in nerve cells such as neurons. In the present study, a spinal cord injury mouse model was constructed using wild-type (WT) and ecto-5'-nucleotidase (CD73)^-/- mice. The results of TUNEL and immunofluorescence assays indicated that the apoptosis of neurons in CD73^-/- mice was increased after spinal cord injury. Dorsal root ganglion (DRG) neurons from WT and CD73^-/- mice were cultured in low glucose and hypoxic conditions to simulate the effects of spinal cord injury on neurons. Subsequently, a western blot assay was used to detect the expression of CD73, caspase-3 and Bcl-2. Flow cytometry was used to detect cell apoptosis and the corresponding kits were used to detect changes in lactate dehydrogenase (LDH), superoxide dismutase (SOD), malondialdehyde (MDA), reactive oxygen species (ROS), adenosine triphosphate (ATP) and cell activity. The results revealed that the apoptosis level of CD73-overexpressing DRG neurons was decreased under anoxia and glucose deficiency. The release of LDH, MDA and the production of ROS in CD73 DRG neurons was decreased, while the synthesis of ATP, the activity of SOD and cell activity increased after hypoxia-hypoglycemia treatment. Additional cellular studies demonstrated that blocking the expression and hydrolase activity of CD73 with α,β-methylene ADP (APCP) could counteract the protective effect of CD73 on neuronal apoptosis, while adenosine (Ado) could rescue the increased apoptosis caused by CD73 deletion. In addition, the cAMP/ protein kinase A (PKA)/cAMP response element-binding protein (CREB) signaling pathway was also positively regulated by CD73 and Ado. In conclusion, CD73 could inhibit DRG neuronal apoptosis by promoting the Ado/cAMP/PKA/CREB pathway.

Successful management of spinal cord ischemia in a pediatric patient with fibrocartilaginous embolism: illustrative case

BACKGROUND

Fibrocartilaginous embolism (FCE) is a rare cause of ischemic myelopathy that occurs when the material of the nucleus pulposus migrates into vessels supplying the spinal cord. The authors presented a case of pediatric FCE that was successfully managed by adapting evidence-based recommendations used for spinal cord neuroprotection in aortic surgery.

OBSERVATIONS

A 7-year-old boy presented to the emergency department with acute quadriplegia and hemodynamic instability that quickly progressed to cardiac arrest. After stabilization, the patient regained consciousness but remained in a locked-in state with no spontaneous breathing. The patient presented a diagnostic challenge. Traumatic, inflammatory, infectious, and ischemic etiologies were considered. Eventually, the clinical and radiological findings led to the presumed diagnosis of FCE. Treatment with continuous cerebrospinal fluid drainage (CSFD), pulse steroids, and mean arterial pressure augmentation was applied, with subsequent considerable and consistent neurological improvement.

LESSONS

The authors proposed consideration of the adaptation of spinal cord neuroprotection principles used routinely in aortic surgery for the management of traumatic spinal cord ischemia (FCE-related in particular), namely, permissive arterial hypertension and CSFD. This is hypothesized to allow for the maintenance of sufficient spinal cord perfusion until adequate physiological blood perfusion is reestablished (remodeling of the collateral arterial network and/or clearing/absorption of the emboli).

The Efficacy of Combined Medication With Methylprednisolone and Erythropoietin in the Treatment of Ischemia-Reperfusion Injury to the Spinal Cord in Patients With Cervical Spondylotic Myelopathy

Introduction

Cervical myelopathy (CM) is caused by degenerative or congenital changes in the discs and soft tissues of the cervical spine, leading to chronic compression of the spinal cord. The current treatment for moderate-to-severe CM is surgical decompression, which is effective in most cases; however, it can cause inflammation of the nervous system and spinal cord reperfusion injury, resulting in perioperative neurological complications and suboptimal neurological recovery. The aim of this study was to investigate the therapeutic effects of the combination of erythropoietin and methylprednisolone in the treatment of ischemia-reperfusion injury to the spinal cord and to analyze its effects on the levels of interleukin-1 beta (IL-1β), interleukin-1 receptor antagonist (IL-1RA), and interleukin-8 (IL-8).

Materials and methods

This study included 110 patients admitted to the hospital due to cervical spondylotic myelopathy. They were randomized into two groups of 55 patients each: a control and an observation group. In both groups of patients, fusion internal fixation and anterior cervical discectomy were performed. The difference, however, was that the control group received a rapid intravenous injection of 30 mg/kg methylprednisolone 30 minutes prior to spinal cord decompression, while the observation group received an intravenous injection of 30 mg/kg methylprednisolone and 3,000 U/kg erythropoietin 30 minutes before spinal cord decompression. The study was approved by the Hospital Ethical Committee of the Dow University of Health Sciences, Karachi. The neurological function of both groups of patients was assessed before the procedure and three months after the treatment using the Japanese Orthopedic Association (JOA) method of assessing spinal cord function (40-point rating method). Enzyme-linked immunosorbent assay (ELISA) was performed to measure the levels of neuron-specific enolase (NSE), S-100β, IL-1RA, IL-1β, and IL-8 in both groups. The quality of life of patients in both groups was assessed three months after the treatment with the World Health Organization Quality of Life assessment instrument (WHOQOL-100).

Results

Before the treatment, there was no significant variance between the two groups in the JOA score and the 40-point rating method. Similarly, there was no significant difference in the levels of IL-1β, IL-1RA, and IL-8 between the two groups (p-value = 0.262, 0.387, and 0.154 respectively) prior to the treatment. Three months after the treatment, the levels of IL-1β and IL-8 in the observation group were 21.83 ±3.65 ng/l and 357.07 ±32.36 ng/l respectively, both lower than the control group value (p-value = 0.026, 0.028 respectively). The level of IL-1RA in follow-up was 21.59 ±1.15 ng/l, which was higher than that in the control group. Three months after the treatment, all the WHOQOL-100 parameters of the observation group for psychology, physiology, social relations, independence, spirituality, environment, and general quality of life were higher than those of the control group; the variance among the groups was statistically significant (p-value: <0.001).

Conclusions

The combination therapy with erythropoietin and methylprednisolone is effective for ischemia-reperfusion injuries of the spinal cord. It also reduces S-100β and NSE, inhibits IL-1β, and increases IL-8 and IL-1RA. Therefore, it preserves and improves spinal nerve function and the quality of life of patients.

The transcription factor Foxd3 induces spinal cord ischemia-reperfusion injury by potentiating microRNA-214-dependent inhibition of Kcnk2

Spinal cord injury after surgical repair of the thoracic or thoracoabdominal aorta is a devastating complication that is associated with pathological changes, including inflammation, edema, and nerve cell damage. Recently, microRNA (miRNA)-modulated control of spinal cord injury has been actively investigated. This study aims to clarify the regulatory effect of miR-214-mediated inhibition of Kcnk2 following spinal cord ischemia-reperfusion injury (SCII) and the possible underlying mechanisms. SCII was induced in rats by occluding the aortic arch followed by reperfusion. Gain-of-function and loss-of-function experiments were conducted to explore the modulatory effects of Foxd3, miR-214 and Kcnk2 on PC12 cells under hypoxia/reoxygenation (H/R) conditions. MiR-214 and Kcnk2 were poorly expressed, while Foxd3 was highly expressed in the rat spinal cord tissues and H/R-treated PC12 cells. Kcnk2 overexpression enhanced the viability and inhibited the apoptosis of the H/R-treated PC12 cells. Notably, Foxd3 activated miR-214, and miR-214 targeted Kcnk2. In addition, upregulation of Kcnk2 or knockdown of Foxd3 promoted the cell viability and reduced the apoptosis of the H/R-treated PC12 cells. Overall, our study identified a novel mechanism of Foxd3/miR-214/Kcnk2 involving SCII, suggesting that either Foxd3 or miR-214 may be a novel target for the treatment of SCII.

Intensive Gait Treatment Using a Robot Suit Hybrid Assistive Limb in Acute Spinal Cord Infarction: Report of Two Cases

CONTEXT

Spinal cord infarction (SCI) causes gait disturbance because of paresis, spasticity, and sensory disturbance of the lower limbs. There is no effective medical treatment for SCI, and conventional rehabilitation alone is the main approach to helping individuals work toward independent walking. The aim of this study was to evaluate the effect of gait treatment using the Hybrid Assistive Limb (HAL) on acute SCI.

FINDINGS

A 61-year-old female and a 62-year-old male with incomplete paraplegia participated in this study. Our study participants received gait treatment with HAL 3-4 times per week, with a total of 7-8 sessions (20 min), in addition to conventional physical therapy. The American Spinal Injury Association Impairment Scale, Lower Extremity Motor Score (LEMS), Modified Ashworth Scale (MAS), the Walking Index for Spinal Cord Injury (WISCI II), comfortable gait speed (CGS), stride, cadence, Barthel Index (BI), Functional Independence Measure (FIM), modified Rankin Scale (mRS), joint angles, and adverse effects were assessed prior to HAL treatment and post-HAL treatment. HAL facilitated intensive gait treatment in people during the acute phase after SCI. Improvements in LEMS, WISCI II, CGS, stride, cadence, BI, FIM, mRS, and joint angles were observed in both study participants. Furthermore, decreased spasticity in the gastrocnemius muscle was found in one participant as assessed by MAS.

CONCLUSION

Gait treatment using HAL may be beneficial for paraplegic, non-ambulatory individuals with acute SCI. HAL may be useful for intensive gait treatment without increasing spasticity.

Activation of SK/KCa Channel Attenuates Spinal Cord Ischemia-Reperfusion Injury via Anti-oxidative Activity and Inhibition of Mitochondrial Dysfunction in Rabbits

Spinal cord ischemia-reperfusion injury (SCI/R) is a rare but devastating disorder with a poor prognosis. Small conductance calcium-activated K⁺ (SK/K_Ca) channels are a family of voltage-independent potassium channels that are shown to participate in the pathological process of several neurological disorders. The aim of this study was to investigate the role of SK/K_Ca channels in experimental SCI/R in rabbits. The expression of SK/K_Ca1 protein significantly decreased in both cytoplasm and mitochondria in spinal cord tissues after SCI/R. Treatment with 2 mg/kg NS309, a pharmacological activator for SK/K_Ca channel, attenuated SCI/R-induced neuronal loss, spinal cord edema and neurological dysfunction. These effects were still observed when the administration was delayed by 6 h after SCI/R initiation. NS309 decreased the levels of oxidative products and promoted activities of antioxidant enzymes in both serum and spinal cord tissues. The results of ELISA assay showed that NS309 markedly decreased levels of pro-inflammatory cytokines while increased anti-inflammatory cytokines levels after SCI/R. In addition, treatment with NS309 was shown to preserve mitochondrial respiratory complexes activities and enhance mitochondrial biogenesis. The results of western blot analysis showed that NS309 differentially regulated the expression of mitochondrial dynamic proteins. In summary, our results demonstrated that the SK/K_Ca channel activator NS309 protects against SCI/R via anti-oxidative activity and inhibition of mitochondrial dysfunction, indicating a therapeutic potential of NS309 for SCI/R.

CNB-001 reduces paraplegia in rabbits following spinal cord ischemia

Spinal cord ischemia associated with trauma and surgical procedures including thoraco-abdominal aortic aneurysm repair and thoracic endovascular aortic repair results in devastating clinical deficits in patients. Because spinal cord ischemia is inadequately treated, we studied the effects of [4-((1E)-2-(5-(4-hydroxy-3-methoxystyryl-)-1-phenyl-1H-pyrazoyl-3-yl) vinyl)-2-methoxy-phenol)] (CNB-001), a novel curcumin-based compound, in a rabbit SCI model. CNB-001 is known to inhibit human 5-lipoxygenase and 15-lipoxygenase and reduce the ischemia-induced inflammatory response. Moreover, CNB-001 can reduce the level of oxidative stress markers and potentiate brain-derived neurotrophic factor and brain-derived neurotrophic factor receptor signaling. The Tarlov scale and quantal analysis technique results revealed that CNB-001 administered as an intravenous dose (bolus) 30 minutes prior to spinal cord ischemia improved the behaviors of female New Zealand White rabbits. The improvements were similar to those produced by the uncompetitive N-methyl-D-aspartate receptor antagonist memantine. At 48 hours after aortic occlusion, there was a 42.7% increase (P < 0.05) in tolerated ischemia duration (n = 14) for rabbits treated with CNB-001 (n = 16), and a 72.3% increase for rabbits treated with the positive control memantine (P < 0.05) (n = 23) compared to vehicle-treated ischemic rabbits (n = 22). CNB-001 is a potential important novel treatment for spinal cord ischemia induced by aortic occlusion. All experiments were approved by the CSMC Institutional Animal Care and Use Committee (IACUC #4311) on November 1, 2012.

The protective effect of microRNA-21 in neurons after spinal cord injury

STUDY DESIGN

Experimental animal study.

OBJECTIVES

To validate the anti-apoptosis effect of microRNA-21 in neurons after spinal cord injury (SCI) and explore the mechanism.

SETTING

Xiangya Hospital, Central South University, Changsha, Hunan, People's Republic of China.

METHODS

In situ hybridization was used to detect the expression of miR-21 in spinal cord neurons (n = 24). In a rat contusion SCI model (n = 48), we upregulated the miR-21 level around the injured area using miR-21 lentiviral vectors and evaluated the therapeutic effect with histology and behavioural scores. In neuronal cells, oxygen-glucose deprivation (OGD) was exerted to imitate SCI, and we explored the biomechanism using molecular biology and a dual-luciferase reporter assay.

RESULTS

miR-21 was expressed in spinal cord neurons and was found to improve neuronal survival and promote functional recovery in rat SCI models. The in vitro results in PC-12 cells revealed that the augmentation of endogenous miR-21 was able to reduce neuronal cell death after OGD. In addition, overexpression of miR-21 was able to reduce cellular apoptosis via decreasing PDCD4 protein levels, and caspase-3 activity was also influenced. Transfection of miR-21 into 293T cells was able to decrease luciferase activity in a reporter assay system, including the 3' untranslated region of PDCD4.

CONCLUSIONS

miR-21 may have a protective role in neuronal apoptosis after SCI. PDCD4 may be a functional target gene involved in the miR-21-mediated anti-apoptotic effect through an miR-21/PDCD4/caspase-3 pathway.

Spinal Cord Infarction with Aortic Dissection

Spinal cord infarction is an uncommon but devastating disorder caused by various conditions. Aortic dissection is a possible etiological factor and is usually associated with severe chest or back pain. We encountered two cases of spinal cord infarction associated with aortic dissection that presented without typical severe pain, and each case resulted in a different clinical course. Aortic dissection should be considered a cause of spinal cord infarction even if there is little or no pain. The different outcomes in our two patients reflected a difference in their initial functional scores.

Delayed Hospital Presentation and Neuroimaging in Non-surgical Spinal Cord Infarction

BACKGROUND

Lack of timely recognition and neuroimaging may be a barrier to reperfusion efforts in acute spinal cord infarction.

METHODS

We performed a retrospective study of patients diagnosed with acute non-surgical spinal cord infarction at our tertiary academic center from 2001 to 2015. We studied parameters associated with time from symptom onset to initial hospital presentation and magnetic resonance imaging (MRI) of the spinal cord.

RESULTS

We identified 39 patients among whom anterior spinal artery syndrome was the most frequent presentation (87.2%) and atherosclerosis the most common etiology (56.4%). Nearly, half of the patients presented to the emergency department on the same day of symptom onset (48.7%) but only nine (23.1%) within the first 6 h. Average time from symptom onset to spinal cord MRI was 3.2 days. We could not identify clinical, radiological, or outcome patterns associated with early vs. delayed presentation and imaging.

DISCUSSION

Our study found a time lag from symptom onset to hospital presentation and spinal cord MRI in patients with acute spinal cord infarction. These findings point at low clinical suspicion of spinal cord syndromes and limited recognition as a potentially treatable medical emergency.

ZL006 protects spinal cord neurons against ischemia-induced oxidative stress through AMPK-PGC-1α-Sirt3 pathway

Spinal cord ischemia (SCI) induces a range of cellular and molecular cascades, including activation of glutamate receptors and downstream signaling. Post-synaptic density protein 95 (PSD-95) links neuronal nitric oxide synthase (nNOS) with the N-methyl-d-aspartic acid (NMDA) receptors to form a ternary complex in the CNS. This molecular complex-mediated cytotoxicity has been implicated in brain ischemia, but its role in SCI has not been determined. The goal of the study was to investigate the potential protective effects of ZL006, a small-molecule inhibitor of the PSD-95/nNOS interaction, in an in vitro SCI model induced by oxygen and glucose deprivation (OGD) in cultured spinal cord neurons. We found that ZL006 reduced OGD-induced lactate dehydrogenase (LDH) release, neuronal apoptosis and loss of cell viability. This protection was accompanied by the preservation of mitochondrial function, as evidenced by reduced mitochondrial oxidative stress, attenuated mitochondrial membrane potential (MMP) loss, and enhanced ATP generation. In addition, ZL006 stimulated mitochondrial enzyme activities and SOD2 deacetylation in a Sirt3-dependent manner. The results of western blot analysis showed that ZL006 increased the activation of AMPK-PGC-1α-Sirt3 pathway, and the beneficial effects of ZL006 was partially abolished by AMPK inhibitor and PGC-1α knockdown. Therefore, our present data showed that, by the AMPK-PGC-1α-Sirt3 pathway, ZL006 protects spinal cord neurons against ischemia through reducing mitochondrial oxidative stress to prevent apoptosis.