The impact of riluzole on neurobehavioral outcomes in preclinical models of traumatic and nontraumatic spinal cord injury: results from a systematic review of the literature

Study Design:Systematic review.Objective:To evaluate the impact of riluzole on neurobehavioral outcomes in preclinical models of nontraumatic and traumatic spinal cord injury (SCI).Methods:An extensive search of the literature was conducted in Medline, EMBASE, and Medline in Process. Studies were included if they evaluated the impact of riluzole on neurobehavioral outcomes in preclinical models of nontraumatic and traumatic SCI. Extensive data were extracted from relevant studies, including sample characteristics, injury model, outcomes assessed, timing of evaluation, and main results. The SYRCLE checklist was used to assess various sources of bias.Results:The search yielded a total of 3180 unique citations. A total of 16 studies were deemed relevant and were summarized in this review. Sample sizes ranged from 14 to 90, and injury models included traumatic SCI (n = 9), degenerative cervical myelopathy (n = 2), and spinal cord-ischemia (n = 5). The most commonly assessed outcome measures were BBB (Basso, Beattie, Besnahan) locomotor score and von Frey filament testing. In general, rats treated with riluzole exhibited significantly higher BBB locomotor scores than controls. Furthermore, riluzole significantly increased withdrawal thresholds to innocuous stimuli and tail flick latency following application of radiant heat stimuli. Finally, rats treated with riluzole achieved superior results on many components of gait assessment.Conclusion:In preclinical models of traumatic and nontraumatic SCI, riluzole significantly improves locomotor scores, gait function, and neuropathic pain. This review provides the background information necessary to interpret the results of clinical trials on the impact of riluzole in traumatic and nontraumatic SCI

Mechanistic Insights and Neuroprotective Approaches to Enhance Recovery in Cervical Spondylotic Myelopathy

The overarching term degenerative cervical myelopathy (DCM) describes the cervical spinal cord compression induced by degenerative changes in the cervical spine. DCM appears as the most common cause of spinal cord dysfunction. Cervical spondylotic myelopathy (CSM), the most common form of DCM, causes significant neurological disabilities including motor, sensory and autonomic impairments. Surgical decompression represents the mainstay of treatment for this common disease. However, many patients do not exhibit full neurological recovery and a number of them can experience neurological deterioration in the acute or subacute phase after surgery. Currently, no pharmacological strategies are available to these patients. Riluzole, a sodium channel blocker, has been shown to be neuroprotective in models of acute spinal cord injury and to attenuate neural degeneration in clinical trials of amyotrophic lateral sclerosis. To test the efficacy of riluzole in experimental CSM, we initially administered riluzole in a rat model of CSM created by graduated mechanical compression of the cervical spinal cord. We found significant tissue sparing, alleviation of neuropathic pain and improvement in locomotor function. However, this model does not allow for surgical decompression and is not MRI compatible. This provided the impetus to develop a novel animal model of CSM that reproduces the chronic, progressive compression of the cervical spinal cord, mimics the clinical and histopathological features of human CSM, is MRI compatible and allows for microsurgical decompression. Using this novel model I discovered that surgical decompression induces early post-operative ischemia-reperfusion injury in the rat cervical spinal cord that was associated with subacute neurological deterioration. These changes were correlated to a subset of patients in the AOSpine CSM prospective study which also exhibited perioperative neurological decline. Of note, riluzole reduced the decompression-mediated reperfusion injury of neurons. Moreover, the combinatorial strategy of microsurgical decompression and riluzole administration resulted in superior preservation of neurons and improvement of neurological function compared to decompressive surgery alone. These results demonstrate the development of ischemia reperfusion injury after surgical decompression in CSM and the potential role of riluzole in alleviating this injury and promoting neurological recovery in CSM.Ph.D

The study of molecular mechanisms of cervical spondylotic myelopathy

Although cervical spondylotic myelopathy (CSM) represents the most common cause of spinal cord impairment among individuals over 55 years old, the molecular mechanisms of the disease remain mainly unknown. To date, many experimental studies have been conducted to establish a reliable model of CSM, however most of them appear some limitations. In this study we aim to create a new animal model of CSM, which will reproduce the temporal course of the human disease and the local microenvironment at the site of spinal cord compression. Methods: Following C7 posterior laminectomy, a thin sheet of aromatic polyether was implanted underneath C5–C6 laminae of the New Zealand rabbits. A sham group in which the material was removed 30 sec after the implantation was also included. Motor function evaluation was performed after the material implantation and weekly thereafter using the Tarlov classification. At 20 weeks post-material implantation electrophysiological studies were also conducted. All the animals were sacrificed 20 weeks post-material implantation and histological and immunohistochemical studies were performed. Results: Clinical evaluation of animals after operation reveals no symptoms and signs of acute spinal cord injury. Moreover, no neurological deficits were noticed in the sham group during the course of the study. However, the animals which underwent implantation of compression material exhibited progressive neurological deficits throughout the study. Rabbits of the compression group experienced significant increased axonal swelling and demyelination, interstitial edema and myelin sheet fragmentation. Histological evaluation of C5 and C6 laminae (at the site of implantation) reveals osteophyte formation. Moreover, the chronic and progressive compression of the cervical spinal cord resulted in induction of apoptosis as well as in disruption of the basement membrane of vessels. Conclusion: The proposed rabbit CSM model reproduces the temporal evolution of the disease and creates a local microenvironment at the site of spinal cord compression, which shares similar features with that of human disease. STUDY B Introduction: Inflammation, glial scar formation and disruption of spinal cord microvasculature represent some of the principal neuropathological features of CSM. However, the molecular mechanisms which are implicated in these pathophysiological phenomena under the chronic and progressive compression of the cervical spinal cord remain interestingly unexplored. Methods: In this study (B) in order to evaluate the role of NF-κB and extracellular matrix proteins in cervical myelopathy we used the rabbit CSM model which was extensively characterized in study A. Briefly New Zealand rabbits (different cohort of animals than that of the study A) were randomly and blindly divided into the following two groups: CSM (n=15) and sham group (n=15). The expression pattern of p50 and p65 subunits of NF-kB, as well as that of MMP-2, MMP-9, and u-PA, was evaluated in spinal cord sections coming from both groups using immunohistochemistry technique. Statistical analysis was performed using SPSS for Windows, release 12.0 (SPSS Inc., Chicago, IL). Results: CSM animals exhibited statistically significant increased immuoreactivity in both NF-κB subunits, p50 and p65. Moreover, the levels MMP-2, MMP-9, and u-PA were found to be significantly increased in CSM animals compared to controls. Finally, strong positive correlation between NF-κB subunits immunoreactivity and that of MMP-9, MMP-2, and u-PA was demonstrated. Conclusion: The NF-κB pathway as well as the extracellular matrix proteins (MMP-2 and MMP-9) are involved in CSM. However, more studies are needed to clarify the functional role of these molecules in the pathobiology of CSM. - See more at: http://nemertes.lis.upatras.gr/jspui/handle/10889/6245#sthash.7NhgYiWe.dpufΑν και η Αυχενική Σπονδυλωτική Μυελοπάθεια (ΑΣΜ) αποτελεί την πιο κοινή αιτία δυσλειτουργίας νωτιαίου μυελού στους ενήλικες άνω των 55 ετών, οι μοριακοί μηχανισμοί παραμένουν άγνωστοι. Μέχρι σήμερα, πολλές προσπάθειες έχουν διενεργηθεί για την ανάπτυξη ενός αξιόπιστου πειραματικού μοντέλου AΣΜ. Ωστόσο, αρκετά μειονεκτήματα εμφανίζονται σε αυτές τις μελέτες. Στη παρούσα μελέτη έχουμε σκοπό τη δημιουργία ενός νέου, πρωτότυπου πειραματικού μοντέλου ΑΣΜ, το οποίο εξομοιώνει τα ιστολογικά και κλινικά χαρακτηριστικά της ανθρωπίνης νόσου. Mεθοδολογία: Μετά από αφαίερεση του πετάλου του έβδομου αυχενικού σπονδύλου, ένα λεπτό τεμάχιο αρωματικού πολυαιθέρα τοποθετήθηκε κάτω από το πέταλο του έκτου αυχενκού σπονδύλου σε κόνικλους Νέας Ζηλανδίας (Ομάδα ΧΠΠ). Σε μία άλλη ομάδα πειραματόζωων ο αρωματικός πολυαιθέρας αφαιρέθηκε 30 δευτερόλεπτα μετά την εμφύτευση (ομάδα ελέγχου). Νευρολογική εκτίμηση πραγματοποιήθηκε χρησιμοποιώντας τη κλίμακα του Tarlov μετά το πέρας της χειρουργικής διαδικασίας και ακολούθως εβδομαδιαίως. Ηλεκτροφυσιολογικές μελέτες πραγματοποιήθηκαν στις 20 εβδομάδες μετά το χειρουργείο και πριν από τη θυσία των πειραματόζωων. Ακολούθησαν ιστολογικές και ανοσοιστοχημικές μελέτες. Αποτελέσματα: Τα πειραματόζωα που άνηκαν στην ομάδα ελέγχου δεν εμφάνισαν νευρολογικά ελλείμματα κατά τη διάρκεια της μελέτης. Αντιθέτως τα πειραματόζωα που άνηκαν στη ΧΠΠ εμφάνισαν νευρολογικά ελλείματα. Στους νωτιαίους μυελούς προερχόμενους από την ΧΠΠ ομάδα ανεδείχθησαν οι χαρακτηριστικές ιστοπαθολογικές αλλοιώσεις της χρόνιας μυελοπάθειας. Ειδικότερα, ανεδείχθη σπογγώδης εκφύλιση της λευκής ουσίας, διάμεσο οίδημα και αποπλάτυνση των πρόσθιων κεράτων της φαιάς ουσίας. Επίσης ανεδείχθη κατακρήμνιση του μυελικού σάκου και διόγκωση του δακτυλίου της μυελίνης. Τέλος, η χρόνια πίεση του νωτιαίου οδήγησε σε ενεργοποίηση της απόπτωσης και διαταραχή της αρχιτεκτονικής του μικροαγγειακού συστήματος του νωτιαίου μυελού Συμπέρασμα: Το πρωτότυπο μοντέλο ΑΣΜ στους κονίκλους ποσομοιώνει το χωρικό και χρονικό προφίλ της ανθρώπινης νόσου στο σημείο της πίεσης του νωτιαίου μυελού. ΜΕΛΕΤΗ B Εισαγωγή: Η φλεγμονή, η δημιουργία ουλώδους ιστού και η διαταραχή του μικροαγγειακού συστήματος του νωτιαίου μυελού είναι ορισμένα από τα κύρια παθοφυσιολογικά φαινόμενα της ΑΣΜ. Ωστόσο οι μοριακοί μηχανισμοί που εμπλέκονται σε αυτά τα φαινόμενα κάτω από τη χρόνια και προοδευτική πίεση του νωτιαίου μυελού παραμένουν ανεξερεύνητα. Mεθοδολογία: Στη συγκεκριμένη μελέτη χρησιμοποιήθηκε το πειραματικό μοντέλο ΑΣΜ που περιγράφεται στη μελέτη Α με σκοπό να διερευνηθεί ο ρόλος του NF-κB και των πρωτεινών της εξωκυττάριας ουσίας στην ΑΣΜ. Εν συντομία, κόνικλοι Νέας Ζηλανδίας (διαφορετικά πειραματόζωα από εκείνα της μελέτης Α) χωρίστηκαν τυχαία σε δύο ομάδες: την ομάδα ΧΠΠ (n=15) και την ομάδα ελέγχου (n=15). Η έκφραση των πρωτεινών των υπομονάδων p50 και p65 του NF-kB, όπως επίσης και των ενζύμων διάσπασης της εξωκυττάριας ουσίας (MMP-2, MMP-9) και του ενεργοποιητή του πλασμινογόνου τύπου ουροκινάσης (urokinase-type plasminogen activator; u-PA) αξιολογήθηκαν σε τομές νωτιαίων μυελών προερχόμενων και από τις δύο ομάδες χρησιμοποιώντας ανοσοιστοχημική τεχνική. Στατιστική ανάλυση πραγματοποιήθηκε χρησιμοποιώντας SPSS για Windows, release 12.0 (SPSS Inc., Chicago, IL). Αποτελέσματα: Σε τομές νωτιαίων μυελών που προέρχονταν από πειραματόζωα που έπασχαν από ΑΣΜ αναδείχθηκε στατιστικά σημαντικά αυξημένη έκφραση των υπομονάδων του NF-κB (p50 & p65), όπως επίσης και των ενζύμων MMP-2, MMP-9, and u-PA σε σύγκριση με εκείνες που προέρχονταν από την ομάδα ελέγχου. Τέλος, σημαντικά θετική συσχέτιση παρατηρήθηκε μεταξύ των επιπέδων έκφρασης του NF-κB και εκείνων των MMP-9, MMP-2, and u-PA. Συμπέρασμα: Τα ευρήματα αυτά αποτελούν ισχυρές ενδείξεις πως η χρόνια και προοδευτική πίεση του αυχενικού νωτιαίου μυελού οδηγεί σε αυξημένη έκφραση των MMP-2, MMP-9 και u-PA πιθανόν μέσω της δράσης του μεταγραφικού παράγοντα NF-κB. Είναι βέβαιο ότι περισσότερες μελέτες απαιτούνται για την εξακρίβωση του ρόλου των πρωτεινών αυτών στην ΑΣΜ. - See more at: http://nemertes.lis.upatras.gr/jspui/handle/10889/6245#sthash.7NhgYiWe.dpu

Treatment of Recurrent, Twice Coiled, Previously Ruptured Anterior Inferior Cerebellar Artery-Posterior Inferior Cerebellar Artery Aneurysm With Excision and End-to-End Anastomosis: 2-Dimensional Operative Video

Anterior inferior cerebellar artery-posterior inferior cerebellar artery (AICA-PICA) variant is a well-established variant of the vertebrobasilar system. AICA-PICA aneurysms are extremely rare.1-3 There are only 12 cases reported in the literature.1-3 Here, we are presenting a case of a previously ruptured AICA-PICA dissecting aneurysm which had undergone coil embolization twice at an outside institution. The aneurysm continued to grow, and therefore, the patient was transferred to our institution for definitive treatment. Placement of a flow diverter was felt not to be feasible because of the acute bend of the vessel at the neck of the aneurysm. After a retrosigmoid craniotomy, the aneurysm sac was opened to untether the coil mass from the neck of the aneurysm. Clip reconstruction was attempted but intraoperative blood flow measurements demonstrated no flow in the distal outflow artery, indicating that the clip was occluding the parent vessel at the neck because of the challenging geometry and atherosclerosis. We then proceeded with an excision and end-to-end anastomosis of the AICA-PICA. The details of vascular reconstruction while the inflow and outflow arteries are at acute angle are described. Intraoperative indocyanine video angiography demonstrated complete exclusion of the aneurysm from the circulation and patency of the bypass. Postoperative computed tomography angiography demonstrated bypass patency. Postoperatively, the patient required a temporary external ventricular drain for hydrocephalus; however, she was eventually discharged home without any neurological deficits. The patient gave informed consent for the surgery and video recording. Institutional Review Board approval was deemed unnecessary.Anterior inferior cerebellar artery-posterior inferior cerebellar artery (AICA-PICA) variant is a well-established variant of the vertebrobasilar system. AICA-PICA aneurysms are extremely rare.1-3 There are only 12 cases reported in the literature.1-3 Here, we are presenting a case of a previously ruptured AICA-PICA dissecting aneurysm which had undergone coil embolization twice at an outside institution. The aneurysm continued to grow, and therefore, the patient was transferred to our institution for definitive treatment. Placement of a flow diverter was felt not to be feasible because of the acute bend of the vessel at the neck of the aneurysm. After a retrosigmoid craniotomy, the aneurysm sac was opened to untether the coil mass from the neck of the aneurysm. Clip reconstruction was attempted but intraoperative blood flow measurements demonstrated no flow in the distal outflow artery, indicating that the clip was occluding the parent vessel at the neck because of the challenging geometry and atherosclerosis. We then proceeded with an excision and end-to-end anastomosis of the AICA-PICA. The details of vascular reconstruction while the inflow and outflow arteries are at acute angle are described. Intraoperative indocyanine video angiography demonstrated complete exclusion of the aneurysm from the circulation and patency of the bypass. Postoperative computed tomography angiography demonstrated bypass patency. Postoperatively, the patient required a temporary external ventricular drain for hydrocephalus; however, she was eventually discharged home without any neurological deficits. The patient gave informed consent for the surgery and video recording. Institutional Review Board approval was deemed unnecessary

Delayed administration of a bio-engineered zinc-finger VEGF-A gene therapy is neuroprotective and attenuates allodynia following traumatic spinal cord injury.

Following spinal cord injury (SCI) there are drastic changes that occur in the spinal microvasculature, including ischemia, hemorrhage, endothelial cell death and blood-spinal cord barrier disruption. Vascular endothelial growth factor-A (VEGF-A) is a pleiotropic factor recognized for its pro-angiogenic properties; however, VEGF has recently been shown to provide neuroprotection. We hypothesized that delivery of AdV-ZFP-VEGF--an adenovirally delivered bio-engineered zinc-finger transcription factor that promotes endogenous VEGF-A expression--would result in angiogenesis, neuroprotection and functional recovery following SCI. This novel VEGF gene therapy induces the endogenous production of multiple VEGF-A isoforms; a critical factor for proper vascular development and repair. Briefly, female Wistar rats--under cyclosporin immunosuppression--received a 35 g clip-compression injury and were administered AdV-ZFP-VEGF or AdV-eGFP at 24 hours post-SCI. qRT-PCR and Western Blot analysis of VEGF-A mRNA and protein, showed significant increases in VEGF-A expression in AdV-ZFP-VEGF treated animals (p<0.001 and p<0.05, respectively). Analysis of NF200, TUNEL, and RECA-1 indicated that AdV-ZFP-VEGF increased axonal preservation (p<0.05), reduced cell death (p<0.01), and increased blood vessels (p<0.01), respectively. Moreover, AdV-ZFP-VEGF resulted in a 10% increase in blood vessel proliferation (p<0.001). Catwalk™ analysis showed AdV-ZFP-VEGF treatment dramatically improves hindlimb weight support (p<0.05) and increases hindlimb swing speed (p<0.02) when compared to control animals. Finally, AdV-ZFP-VEGF administration provided a significant reduction in allodynia (p<0.01). Overall, the results of this study indicate that AdV-ZFP-VEGF administration can be delivered in a clinically relevant time-window following SCI (24 hours) and provide significant molecular and functional benefits

AdV-ZFP-VEGF improves hindlimb weight support.

<p>Catwalk gait analysis was used to assess hindlimb weight support. A sub-set of animals (with BBB scores >9) were assessed every week between 4–8 weeks, and each animal performed a standardized Catwalk run. A blinded observer analyzed the data. (A) Paw area: the maximal area of the paw print in contact with the detection surface of the CatWalk (expressed in mm²), (B) Paw width: the maximal distance spanning the medial and lateral contact points of the paw (expressed in mm), and (C) Paw length: the maximal distance spanning the cranial and caudal contact points of the paw (expressed in mm). (D) Representative images of CatWalk forelimb (green) and hindlimb (red) prints, which were used to quantify the data presented in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0096137#pone-0096137-g006" target="_blank">Figure 6</a> and <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0096137#pone-0096137-g007" target="_blank">Figure 7</a>. Data presented is the mean ± SEM, n = 5/group, at 8 weeks following SCI. One-way ANOVA (Holm-Sidak post-hoc). *p<0.05, **p<0.005.</p

Electrophysiological assessment following AdV-ZFP-VEGF administration.

<p>(A) Representative tracings of MEP's recorded from the hindlimb at 8 weeks post-injury. (B) MEP quantification. Recordings were obtained from hindlimb biceps femoris. Stimulation was applied to the midline of the cervical spinal cord (0.13 Hz; 0.1 ms; 2 mA; 200 sweeps). Latency was calculated as the time from the start of the stimulus artifact to the first prominent peak. AdV-ZFP-VEGF did not result in improved MEP's. (C) H-Reflex quantification. Recording electrodes were placed two centimeters apart in the mid-calf region and the posterior tibial nerve was stimulated in the popliteal fossa using a 0.1 ms duration square wave pulse at a frequency of 1 Hz. The rats were tested for maximal plantar H-reflex/maximal plantar M-response (H/M) ratios to determine the excitability of the reflex. AdV-ZFP-VEGF administration did not significantly alter the H/M ratio. n = 6/group.</p