Clinical trials in spinal cord injury

Acute spinal cord injury serum biomarkers in human and rat: a scoping systematic review

STUDY DESIGN

Scoping systematic review.

OBJECTIVES

To summarize the available experimental clinical and animal studies for the identification of all CSF and serum-derived biochemical markers in human and rat SCI models.

SETTING

Tehran, Iran.

METHODS

In this scoping article, we systematically reviewed the electronic databases of PubMed, Scopus, WOS, and CENTRAL to retrieve current literature assessing the levels of different biomarkers in human and rat SCI models.

RESULTS

A total of 19,589 articles were retrieved and 6897 duplicated titles were removed. The remaining 12,692 studies were screened by their title/abstract and 12,636 were removed. The remaining 56 were considered for full-text assessment, and 11 papers did not meet the criteria, and finally, 45 studies were included. 26 studies were human observational studies comprising 1630 patients, and 19 articles studied SCI models in rats, including 832 rats. Upon reviewing the literature, we encountered a remarkable heterogeneity in terms of selected biomarkers, timing, and method of measurement, studied models, extent, and mechanism of injury as well as outcome assessment measures.

CONCLUSIONS

The specific expression and distribution patterns of biomarkers in relation to spinal cord injury (SCI) phases, and their varied concentrations over time, suggest that cerebrospinal fluid (CSF) and blood biomarkers are effective measures for assessing the severity of SCI.

Rodent Models of Spinal Cord Injury: From Pathology to Application

Spinal cord injury (SCI) often has devastating consequences for the patient's physical, mental and occupational health. At present, there is no effective treatment for SCI, and appropriate animal models are very important for studying the pathological manifestations, injury mechanisms, and corresponding treatment. However, the pathological changes in each injury model are different, which creates difficulties in selecting appropriate models for different research purposes. In this article, we analyze various SCI models and introduce their pathological features, including inflammation, glial scar formation, axon regeneration, ischemia-reperfusion injury, and oxidative stress, and evaluate the advantages and disadvantages of each model, which is convenient for selecting suitable models for different injury mechanisms to study therapeutic methods.

The Histopathology of Severe Graded Compression in Lower Thoracic Spinal Cord Segment of Rat, Evaluated at Late Post-injury Phase

Spontaneous recovery of lost motor functions is relative fast in rodent models after inducing a very mild/moderate spinal cord injury (SCI), and this may complicate a reliable evaluation of the effectiveness of potential therapy. Therefore, a severe graded (30 g, 40 g and 50 g) weight-compression SCI at the Th9 spinal segment, involving an acute mechanical impact followed by 15 min of persistent compression, was studied in adult female Wistar rats. Functional parameters, such as spontaneous recovery of motor hind limb and bladder emptying function, and the presence of hematuria were evaluated within 28 days of the post-traumatic period. The disruption of the blood-spinal cord barrier, measured by extravasated Evans Blue dye, was examined 24 h after the SCI, when maximum permeability occurs. At the end of the survival period, the degradation of gray and white matter associated with the formation of cystic cavities, and quantitative changes of glial structural proteins, such as GFAP, and integral components of axonal architecture, such as neurofilaments and myelin basic protein, were evaluated in the lesioned area of the spinal cord. Based on these functional and histological parameters, and taking the animal’s welfare into account, the 40 g weight can be considered as an upper limit for severe traumatic injury in this compression model.

An In Vivo Compression Model of Spinal Cord Injury

Animal spinal cord injury (SCI) models have proven highly useful for investigating the mechanisms involved in the injury process and evaluating the effectiveness of experimental therapeutic interventions. Over the last years, substantial improvements have been made in producing consistent and reproducible animal SCI models. Different SCI models have been developed to address the mechanism of injury, being divided into contusion, compression, distraction, dislocation, transection, or chemical models. The method described here is a mouse compression model of SCI that, in many respects, faithfully reproduces SCI in man.

Rodent, large animal and non-human primate models of spinal cord injury

In this narrative review we aimed to assess the usefulness of the different animal models in identifying injury mechanisms and developing therapies for humans suffering from spinal cord injury (SCI). Results obtained from rodent studies are useful but, due to the anatomical, molecular and functional differences, confirmation of these findings in large animals or non-human primates may lead to basic discoveries that cannot be made in rodent models and that are more useful for developing treatment strategies in humans. SCI in dogs can be considered as intermediate between rodent models and human clinical trials, but the primate models could help to develop appropriate methods that might be more relevant to humans. Ideally, an animal model should meet the requirements of availability and repeatability as well as reproduce the anatomical features and the clinical pathological changing process of SCI. An animal model that completely simulates SCI in humans does not exist. The different experimental models of SCI have advantages and disadvantages for investigating the different aspects of lesion development, recovery mechanisms and potential therapeutic interventions. The potential advantages of non-human primate models include genetic similarities, similar caliber/length of the spinal cord as well as biological and physiological responses to injury which are more similar to humans. Among the potential disadvantages, high operating costs, infrastructural requirements and ethical concerns should be considered. The translation from experimental repair strategies to clinical applications needs to be investigated in future carefully designed studies.

Anti-paralytic medicinal plants - Review

Paralysis is the loss of the ability of one or more muscles to move, due to disruption of signaling between the nervous system and muscles. The most common causes of paralysis are stroke, head injury, spinal cord injury (SCI) and multiple sclerosis. The search for cure of paralysis is yet to be found. Many ethnobotanical surveys have reported the use of medicinal plants by various ethnic communities in treating and curing paralysis. The present review discusses the use of medicinal plants in India for ameliorating and curing paralytic conditions, as well as discuses some of the important developments in future possible applications of medicinal plants in treatment of paralysis. This review reports the use of 37 medicinal plants for their application and cure of ailments related to paralysis. Out of the 37 plants documented, 11 plants have been reported for their ability to cure paralysis. However, the information on the documented plants were mostly found to be inadequate, requiring proper authentication with respect to their specificity, dosage, contradictions etc. It is found that despite the claims presented in many ethnobotanical surveys, the laboratory analysis of these plants remain untouched. It is believed that with deeper intervention on analysis of bioactive compounds present in these plants used by ethic traditional healers for paralysis, many potential therapeutic compounds can be isolated for this particular ailment in the near future.

Animal models of spinal cord injury: a systematic review

STUDY DESIGN

PRISMA-guided systematic review.

OBJECTIVES

To provide a comprehensive framework of the current animal models for investigating spinal cord injury (SCI) and categorize them based on the aims, patterns and levels of injury, and outcome measurements as well as animal species.

SETTING

Sina Trauma and Surgery Research Center, Tehran University of Medical Sciences, Tehran, Iran.

METHODS

An electronic search of the Medline database for literature describing animal models of SCI was performed on 1 January 2016 using the following keywords: 'spinal cord injuries' and 'animal models'. The search retrieved 2870 articles. Reviews and non-original articles were excluded. Data extraction was independently performed by two reviewers.

RESULTS

Among the 2209 included studies, testing the effects of drug's or growth factor's interventions was the most common aim (36.6%) followed by surveying pathophysiologic changes (30.2%). The most common spinal region involved was thoracic (81%). Contusion was the most common pattern of injury (41%) followed by transection (32.5%) and compression (19.4%). The most common species involved in animal models of SCI was the rat (72.4%). Two or more types of outcome assessments were used in the majority of the studies, and the most common assessment method was biological plus behavioral (50.8%).

CONCLUSIONS

Prior to choosing an animal model, the objectives of the proposed study must precisely be defined. Contusion and compression models better simulate the biomechanics and neuropathology of human injury, whereas transection models are valuable to study anatomic regeneration. Rodents are the most common and probably best-suited species for preliminary SCI studies.

Evaluation of the neural function of nonhuman primates with spinal cord injury using an evoked potential-based scoring system

Nonhuman primate models of spinal cord injury (SCI) have been widely used in evaluation of the efficacy and safety of experimental restorative interventions before clinical trials. However, no objective methods are currently available for the evaluation of neural function in nonhuman primates. In our long-term clinical practice, we have used evoked potential (EP) for neural function surveillance during operation and accumulated extensive experience. In the present study, a nonhuman primate model of SCI was established in 6 adult cynomologus monkeys through spinal cord contusion injury at T8-T9. The neural function before SCI and within 6 months after SCI was evaluated based on EP recording. A scoring system including somatosensory evoked potentials (SSEPs) and transcranial electrical stimulation-motor evoked potentials (TES-MEPs) was established for the evaluation of neural function of nonhuman primates with SCI. We compared the motor function scores of nonhuman primates before and after SCI. Our results showed that the EP below the injury level significantly changed during the 6 months after SCI. In addition, a positive correlation was identified between the EP scores and motor function. The EP-based scoring system is a reliable approach for evaluating the motor function changes in nonhuman primates with SCI.

Acrolein-mediated conduction loss is partially restored by K⁺ channel blockers

Acrolein-mediated myelin damage is thought to be a critical mechanism leading to conduction failure following neurotrauma and neurodegenerative diseases. The exposure and activation of juxtaparanodal voltage-gated K(+) channels due to myelin damage leads to conduction block, and K(+) channel blockers have long been studied as a means for restoring axonal conduction in spinal cord injury (SCI) and multiple sclerosis (MS). In this study, we have found that 100 μM K(+) channel blockers 4-aminopyridine-3-methanol (4-AP-3-MeOH), and to a lesser degree 4-aminopyridine (4-AP), can significantly restore compound action potential (CAP) conduction in spinal cord tissue following acrolein-mediated myelin damage using a well-established ex vivo SCI model. In addition, 4-AP-3-MeOH can effectively restore CAP conduction in acrolein-damaged axons with a range of concentrations from 0.1 to 100 μM. We have also shown that while both compounds at 100 μM showed no preference of small- and large-caliber axons when restoring CAP conduction, 4-AP-3-MeOH, unlike 4-AP, is able to augment CAP amplitude while causing little change in axonal responsiveness measured in refractory periods and response to repetitive stimuli. In a prior study, we show that 4-AP-3-MeOH was able to functionally rescue mechanically injured axons. In this investigation, we conclude that 4-AP-3-MeOH is an effective K(+) channel blocker in restoring axonal conduction following both primary (physical) and secondary (chemical) insults. These findings also suggest that 4-AP-3-MeOH is a viable alternative of 4-AP for treating myelin damage and improving function following central nervous system trauma and neurodegenerative diseases.

Minimizing errors in acute traumatic spinal cord injury trials by acknowledging the heterogeneity of spinal cord anatomy and injury severity: an observational Canadian cohort analysis

Clinical trials of therapies for acute traumatic spinal cord injury (tSCI) have failed to convincingly demonstrate efficacy in improving neurologic function. Failing to acknowledge the heterogeneity of these injuries and under-appreciating the impact of the most important baseline prognostic variables likely contributes to this translational failure. Our hypothesis was that neurological level and severity of initial injury (measured by the American Spinal Injury Association Impairment Scale [AIS]) act jointly and are the major determinants of motor recovery. Our objective was to quantify the influence of these variables when considered together on early motor score recovery following acute tSCI. Eight hundred thirty-six participants from the Rick Hansen Spinal Cord Injury Registry were analyzed for motor score improvement from baseline to follow-up. In AIS A, B, and C patients, cervical and thoracic injuries displayed significantly different motor score recovery. AIS A patients with thoracic (T2-T10) and thoracolumbar (T11-L2) injuries had significantly different motor improvement. High (C1-C4) and low (C5-T1) cervical injuries demonstrated differences in upper extremity motor recovery in AIS B, C, and D. A hypothetical clinical trial example demonstrated the benefits of stratifying on neurological level and severity of injury. Clinically meaningful motor score recovery is predictably related to the neurological level of injury and the severity of the baseline neurological impairment. Stratifying clinical trial cohorts using a joint distribution of these two variables will enhance a study's chance of identifying a true treatment effect and minimize the risk of misattributed treatment effects. Clinical studies should stratify participants based on these factors and record the number of participants and their mean baseline motor scores for each category of this joint distribution as part of the reporting of participant characteristics. Improved clinical trial design is a high priority as new therapies and interventions for tSCI emerge.

A quantitative analysis of clinical trial designs in spinal cord injury based on ICCP guidelines

Clinical studies of spinal cord injury (SCI) have evolved into multidisciplinary programs that investigate multiple types of neurological deficits and sequelae. In 2007, the International Campaign for Cures of SCI Paralysis (ICCP) proposed best practices for interventional trial designs, end-points, and inclusion criteria. Here we quantitatively assessed the extent to which SCI trials follow ICCP guidelines and reflect the overall patient population. We obtained data for all 288 SCI trials in ClinicalTrials.gov. We calculated summary statistics and observed trends pre-2007 versus 2007 onward. To compare the trial population to the overall SCI population, we obtained statistics from the National SCI Statistical Center. We generated tag clouds to describe heterogeneous trial outcomes. Most interventional studies were randomized (147, 73.1%), and utilized active (55, 36.7%) or placebo controls (49, 32.7%), both increasing trends (p=0.09). Most trials were open label (116, 53.5%), rather than double- (62, 28.6%) or single-blinded (39, 18.0%), but blinding has increased (p=0.01). Tag clouds of outcomes suggest an emphasis on assessment using scores and scales. Inclusion criteria related to American Spinal Injury Association (ASIA) status and neurological level allowed inclusion of most SCI patients. Age inclusion criteria were most commonly 18-65 or older. Consistent with ICCP recommendations, most trials were randomized and controlled, and blinding has increased. Age inclusion criteria skew older than the overall population. ASIA status criteria reflect the population, but neurological lesion criteria could be broadened. Investigators should make trial designs and results available in a complete manner to enable comparisons of populations and outcomes.

Animal models of neurologic disorders: a nonhuman primate model of spinal cord injury

Primates are an important and unique animal resource. We have developed a nonhuman primate model of spinal cord injury (SCI) to expand our knowledge of normal primate motor function, to assess the impact of disease and injury on sensory and motor function, and to test candidate therapies before they are applied to human patients. The lesion model consists of a lateral spinal cord hemisection at the C7 spinal level with subsequent examination of behavioral, electrophysiological, and anatomical outcomes. Results to date have revealed significant neuroanatomical and functional differences between rodents and primates that impact the development of candidate therapies. Moreover, these findings suggest the importance of testing some therapeutic approaches in nonhuman primates prior to the use of invasive approaches in human clinical trials. Our primate model is intended to: 1) lend greater positive predictive value to human translatable therapies, 2) develop appropriate methods for human translation, 3) lead to basic discoveries that might not be identified in rodent models and are relevant to human translation, and 4) identify new avenues of basic research to "reverse-translate" important questions back to rodent models.

Translational spinal cord injury research: preclinical guidelines and challenges

Advances in the neurobiology of spinal cord injury (SCI) have prompted increasing attention to opportunities for moving experimental strategies towards clinical applications. Preclinical studies are the centerpiece of the translational process. A major challenge is to establish strategies for achieving optimal translational progression while minimizing potential repetition of previous disappointments associated with clinical trials. This chapter reviews and expands upon views pertaining to preclinical design reported in recently published opinion surveys. Subsequent discussion addresses other preclinical considerations more specifically related to current and potentially imminent cellular and pharmacological approaches to acute/subacute and chronic SCI. Lastly, a retrospective and prospective analysis examines how guidelines currently under discussion relate to select examples of past, current, and future clinical translations. Although achieving definition of the "perfect" preclinical scenario is difficult to envision, this review identifies therapeutic robustness and independent replication of promising experimental findings as absolutely critical prerequisites for clinical translation. Unfortunately, neither has been fully embraced thus far. Accordingly, this review challenges the notion "everything works in animals and nothing in humans", since more rigor must first be incorporated into the bench-to-bedside translational process by all concerned, whether in academia, clinical medicine, or corporate circles.

Syndromics: a bioinformatics approach for neurotrauma research

Substantial scientific progress has been made in the past 50 years in delineating many of the biological mechanisms involved in the primary and secondary injuries following trauma to the spinal cord and brain. These advances have highlighted numerous potential therapeutic approaches that may help restore function after injury. Despite these advances, bench-to-bedside translation has remained elusive. Translational testing of novel therapies requires standardized measures of function for comparison across different laboratories, paradigms, and species. Although numerous functional assessments have been developed in animal models, it remains unclear how to best integrate this information to describe the complete translational "syndrome" produced by neurotrauma. The present paper describes a multivariate statistical framework for integrating diverse neurotrauma data and reviews the few papers to date that have taken an information-intensive approach for basic neurotrauma research. We argue that these papers can be described as the seminal works of a new field that we call "syndromics", which aim to apply informatics tools to disease models to characterize the full set of mechanistic inter-relationships from multi-scale data. In the future, centralized databases of raw neurotrauma data will enable better syndromic approaches and aid future translational research, leading to more efficient testing regimens and more clinically relevant findings.

The ameliorating effect of dantrolene on the morphology of urinary bladder in spinal cord injured rats

In animal models of spinal cord injury (SCI), the urinary bladder can undergo significant structural and physiological alterations. Dantrolene has been shown to be neuroprotective by reducing neuronal apoptosis after SCI. Furthermore, in addition to its anti-inflammatory and antioxidant properties, it appears to have a beneficial action on voiding, once this drug acts on the external urethral sphincter relaxation. In the present study, we investigated the effects of dantrolene on urinary bladder injury that follows experimental SCI. Forty-six male Wistar rats were laminectomized at T13, and a compressive trauma was performed to induce SCI. After euthanasia, the urinary bladder was removed for gross and histological evaluation. Traumatized animals showed urinary retention with severe hemorrhagic cystitis. Injured animals treated with dantrolene had less bladder hemorrhage and inflammatory infiltrate than those treated with placebo (p<0.05). Our results demonstrate that dantrolene may protect against urinary bladder lesions that follow SCI. Treating spinal cord-injured patients with this agent may be a promising additional therapeutic strategy to alleviate the accompanying inflammatory process. The results of the current study show that dantrolene has protective effects on spinal cord contusion-induced urinary bladder injury. The impaired integrity of bladder morphology was ameliorated by dantrolene treatment.

Axon regeneration requires coordinate activation of p38 and JNK MAPK pathways

Signaling pathways essential for axon regeneration, but not for neuron development or function, are particularly well suited targets for therapeutic intervention. We find that the parallel PMK-3(p38) and KGB-1(JNK) MAPK pathways must be coordinately activated to promote axon regeneration. Axon regeneration fails if the activity of either pathway is absent. These two MAPKs are coregulated by the E3 ubiquitin ligase RPM-1(Phr1) via targeted degradation of the MAPKKKs DLK-1 and MLK-1 and by the MAPK phosphatase VHP-1(MKP7), which negatively regulates both PMK-3(p38) and KGB-1(JNK).

Mismatch Between Investigator-Determined and Patient-Reported Independence After Spinal Cord Injury

Objective. This study investigated the course and relationship between investigator-determined and patient-reported level of independence within the first year after spinal cord injury (SCI). The authors examined variables that contributed to these scores. Methods. In this observational cohort study, 73 patients with traumatic SCI were evaluated at 1, 3, and 6 months (and 40 subjects at 1 to 12 months). The investigator-determined independence was quantified using the Spinal Cord Independence Measure (SCIM). The subjective, patient-reported independence was determined by asking how their general restrictions influenced everyday life activities. Several variables were used to explain these 2 scores. Results. The SCIM score was higher than the patient-reported independence and improved significantly more over time (up to about 70/100 at 12 months), whereas the perceived independence remained below 50/100. The correlations between the 2 measures were at most moderate ( rs ≤ 0.51), but in general somewhat higher for subjects with tetraplegia. Age and muscle strength predicted the SCIM score well. No variable predicted the patient-reported level of independence. Conclusions. Investigator-determined and patient-reported outcomes can differ considerably and evolve differently. A patient-reported outcome measure may not detect actual functional improvement. It is likely that changes in patient-reported outcomes are influenced by many factors in addition to those associated with functional recovery, including psychological factors.

Extrinsic and intrinsic factors controlling axonal regeneration after spinal cord injury

Spinal cord injury is one of the most devastating conditions that affects the central nervous system. It can lead to permanent disability and there are around two million people affected worldwide. After injury, accumulation of myelin debris and formation of an inhibitory glial scar at the site of injury leads to a physical and chemical barrier that blocks axonal growth and regeneration. The mammalian central nervous system thus has a limited intrinsic ability to repair itself after injury. To improve axonal outgrowth and promote functional recovery, it is essential to identify the various intrinsic and extrinsic factors controlling regeneration and navigation of axons within the inhibitory environment of the central nervous system. Recent advances in spinal cord research have opened new avenues for the exploration of potential targets for repairing the cord and improving functional recovery after trauma. Here, we discuss some of the important key molecules that could be harnessed for repairing spinal cord injury.

Administration of autologous bone marrow stem cells into spinal cord injury patients via multiple routes is safe and improves their quality of life: comprehensive case studies

Presently, there is no cure or effective treatment for spinal cord injury (SCI). Studies in SCI patients have shown that for a treatment to be effective it must primarily improve their quality of life. Numerous studies have shown that stem cells represent an alternative treatment for various disorders and have shown promise in several disease/trauma states. For instance, the use of autologous CD34+ stem cells has been shown to ameliorate symptoms of several disorders such as leukemia, cardiomyopathy, diabetes, and several autoimmune diseases, including multiple sclerosis. For the first time, we report eight case studies of SCI (four acute, four chronic) with approximately 2 years of follow-up that were administered bone marrow stem cells (BMSCs) via multiple routes: directly into the spinal cord, directly into the spinal canal, and intravenous. Magnetic resonance imaging illustrated morphological changes in the spinal cord of some of the patients following BMSCs administration. Comprehensive evaluations demonstrate improvements in ASIA, Barthel (quality of life), Frankel, and Ashworth scoring. Moreover, in order to assess bladder function, we designed a simple numerical clinical scoring system that demonstrates significant changes in bladder function following BMSCs administration. To date, we have administration BMSCs into 52 patients with SCI and have had no tumor formations, no cases of infection or increased pain, and few instances of minor adverse events. These studies demonstrate that BMSCs administration via multiple routes is feasible, safe, and may improve the quality of life for patients living with SCI.

Pathology dynamics predict spinal cord injury therapeutic success

Secondary injury, the complex cascade of cellular events following spinal cord injury (SCI), is a major source of post-insult neuron death. Experimental work has focused on the details of individual factors or mechanisms that contribute to secondary injury, but little is known about the interactions among factors leading to the overall pathology dynamics that underlie its propagation. Prior hypotheses suggest that the pathology is dominated by interactions, with therapeutic success lying in combinations of neuroprotective treatments. In this study, we provide the first comprehensive, system-level characterization of the entire secondary injury process using a novel relational model methodology that aggregates the findings of approximately 250 experimental studies. Our quantitative examination of the overall pathology dynamics suggests that, while the pathology is initially dominated by "fire-like", rate-dependent interactions, it quickly switches to a "flood-like", accumulation-dependent process with contributing factors being largely independent. Our evaluation of approximately 20,000 potential single and combinatorial treatments indicates this flood-like pathology results in few highly influential factors at clinically realistic treatment time frames, with multi-factor treatments being merely additive rather than synergistic in reducing neuron death. Our findings give new fundamental insight into the understanding of the secondary injury pathology as a whole, provide direction for alternative therapeutic strategies, and suggest that ultimate success in treating SCI lies in the pursuit of pathology dynamics in addition to individually involved factors.

Clinical studies in spinal cord injury: moving towards successful trials

Spinal cord injury is a devastating condition for which there is still no cure. Many new therapies have emerged in the past few decades that have attempted to improve the outcome after injury, with varying levels of supporting experimental and clinical data. Most studies have been preliminary and have lacked control groups, but positive results can often be embraced by clinicians and patients who are faced without an alternative, despite the poor design and bias of many studies. This article is a review of clinical studies in spinal cord injury and discusses guidelines for future clinical trial design.

Functional recovery measures for spinal cord injury: an evidence-based review for clinical practice and research

BACKGROUND/OBJECTIVE

The end goal of clinical care and clinical research involving spinal cord injury (SCI) is to improve the overall ability of persons living with SCI to function on a daily basis. Neurologic recovery does not always translate into functional recovery. Thus, sensitive outcome measures designed to assess functional status relevant to SCI are important to develop.

METHOD

Evaluation of currently available SCI functional outcome measures by a multinational work group.

RESULTS

The 4 measures that fit the prespecified inclusion criteria were the Modified Barthel Index (MBI), the Functional Independence Measure (FIM), the Quadriplegia Index of Function (QIF), and the Spinal Cord Independence Measure (SCIM). The MBI and the QIF were found to have minimal evidence for validity, whereas the FIM and the SCIM were found to be reliable and valid. The MBI has little clinical utility for use in the SCI population. Likewise, the FIM applies mainly when measuring burden of care, which is not necessarily a reflection of functional recovery. The QIF is useful for measuring functional recovery but only in a subpopulation of people with SCI, and substantial validity data are still required. The SCIM is the only functional recovery outcome measure designed specifically for SCI.

CONCLUSIONS

The multinational work group recommends that the latest version of the SCIM (SCIM III) continue to be refined and validated and subsequently implemented worldwide as the primary functional recovery outcome measure for SCI. The QIF may continue to be developed and validated for use as a supplemental tool for the nonambulatory tetraplegic population.

Chondroitinase ABC improves basic and skilled locomotion in spinal cord injured cats

Chondroitin sulfate proteoglycans (CSPGs) are upregulated in the central nervous system following injury. Chondroitin sulfate glycosaminoglycan (CS GAG) side chains substituted on this family of molecules contribute to the limited functional recovery following injury by restricting axonal growth and synaptic plasticity. In the current study, the effects of degrading CS GAGs with Chondroitinase ABC (Ch'ase ABC) in the injured spinal cords of adult cats were assessed. Three groups were evaluated for 5 months following T10 hemisections: lesion-only, lesion+control, and lesion+Ch'ase ABC. Intraspinal control and Ch'ase ABC treatments to the lesion site began immediately after injury and continued every other day, for a total of 15 treatments, using an injectable port system. Delivery and in vivo cleavage were verified anatomically in a subset of cats across the treatment period. Recovery of skilled locomotion (ladder, peg, and beam) was significantly accelerated, on average, by >3 weeks in Ch'ase ABC-treated cats compared to controls. Ch'ase ABC-treated cats also showed greater recovery of specific skilled locomotor features including intralimb movement patterns and significantly greater paw placement onto pegs. Although recovery of basic locomotion (bipedal treadmill and overground) was not accelerated, intralimb movement patterns were more normal in the Ch'ase ABC-treated cats. Qualitative assessment of serotonergic immunoreactivity also suggested that Ch'ase ABC treatment enhanced plasticity. Finally, analyses using fluorophore-assisted carbohydrate electrophoresis (FACE) indicate CS GAG content is similar in cat and human. These findings show, for the first time, that intraspinal cleavage of CS GAGs can enhance recovery of function following spinal cord injury in large animals with sophisticated motor behaviors and axonal growth requirements similar to those encountered in humans.

Sensory afferents regenerated into dorsal columns after spinal cord injury remain in a chronic pathophysiological state

Axon regeneration after experimental spinal cord injury (SCI) can be promoted by combinatorial treatments that increase the intrinsic growth capacity of the damaged neurons and reduce environmental factors that inhibit axon growth. A prior peripheral nerve conditioning lesion is a well-established means of increasing the intrinsic growth state of sensory neurons whose axons project within the dorsal columns of the spinal cord. Combining such a prior peripheral nerve conditioning lesion with the infusion of antibodies that neutralize the growth inhibitory effects of the NG2 chondroitin sulfate proteoglycan promotes sensory axon growth through the glial scar and into the white matter of the dorsal columns. The physiological properties of these regenerated axons, particularly in the chronic SCI phase, have not been established. Here we examined the functional status of regenerated sensory afferents in the dorsal columns after SCI. Six months post-injury, we located and electrically mapped functional sensory axons that had regenerated beyond the injury site. The regenerated axons had reduced conduction velocity, decreased frequency-following ability, and increasing latency to repetitive stimuli. Many of the axons that had regenerated into the dorsal columns rostral to the injury site were chronically demyelinated. These results demonstrate that regenerated sensory axons remain in a chronic pathophysiological state and emphasize the need to restore normal conduction properties to regenerated axons after spinal cord injury.

Rat Models of Traumatic Spinal Cord Injury to Assess Motor Recovery

Devastating motor, sensory, and autonomic dysfunctions render long-term personal hardships to the survivors of traumatic spinal cord injury (SCI). The suffering also extends to the survivors' families and friends, who endure emotional, physical, and financial burdens in providing for necessary surgeries, care, and rehabilitation. After the primary mechanical SCI, there is a complex secondary injury cascade that leads to the progressive death of otherwise potentially viable axons and cells and that impairs endogenous recovery processes. Investigations of possible cures and of ways to alleviate the hardships of traumatic SCI include those of interventions that attenuate or overcome the secondary injury cascade, enhance the endogenous repair mechanisms, regenerate axons, replace lost cells, and rehabilitate. These investigations have led to the creation of laboratory animal models of the different types of traumatic human SCI and components of the secondary injury cascade. However, no particular model completely addresses all aspects of traumatic SCI. In this article, we describe adult rat SCI models and the motor, and in some cases sensory and autonomic, deficits that each produces. Importantly, as researchers in this area move toward clinical trials to alleviate the hardships of traumatic SCI, there is a need for standardized small and large animal SCI models as well as quantitative behavioral and electrophysiological assessments of their outcomes so that investigators testing various interventions can directly compare their results and correlate them with the molecular, biochemical, and histological alterations.

Therapeutic interventions after spinal cord injury

Spinal cord injury (SCI) can lead to paraplegia or quadriplegia. Although there are no fully restorative treatments for SCI, various rehabilitative, cellular and molecular therapies have been tested in animal models. Many of these have reached, or are approaching, clinical trials. Here, we review these potential therapies, with an emphasis on the need for reproducible evidence of safety and efficacy. Individual therapies are unlikely to provide a panacea. Rather, we predict that combinations of strategies will lead to improvements in outcome after SCI. Basic scientific research should provide a rational basis for tailoring specific combinations of clinical therapies to different types of SCI.