Increasing functional recovery after a cervical spinal cord injury

Spinal cord injury (SCI) in adult mammals results in a loss of function with minimal spontaneous recovery due to secondary damage, the inhibitory nature of the injured adult CNS, and the weak intrinsic axonal growth response of injured neurons. In an attempt to increase the weak growth response I tested if pretreatment of rubrospinal neurons with brain-derived neurotrophic factor (BDNF) one week prior to axotomy or at time of injury would produce functional improvements. Both treatments reduced cell body atrophy and dieback of rubrospinal axons, indicating a cell body response was elicited. However, neither BDNF pretreatment nor acute treatment promoted rubrospinal tract regeneration. In addition, the two-fold increase in rubrospinal tract sprouting into the gray matter rostral to the lesion site did not reach significance. Despite the lack of rubrospinal regeneration, BDNF pretreatment improved functional recovery while BDNF-acute treatment had no effect. The BDNF-treated animals had reduced weight gain and BDNF infusion into the brain has been shown to inhibit food intake. Reduced food intake (dietary restriction) is known to extend lifespan since the 1930s but was recently found to be neuroprotective. I explored the possibility that the improved recovery in the BDNF pretreatment animals was mediated via dietary restriction by testing whether every-other-day fasting (EODF) started one month prior to SCI and continued in the post-injury testing period would also prove effective. EODF animals displayed improved functional recovery, reduced GFAP immunostaining, smaller lesion sizes, and greater numbers of healthy neurons surrounding the lesion area. To test a more clinically relevant treatment I next examined if EODF would promote recovery if initiated after a SCI. EODF promoted better recovery on three independent behavioral tests [i.e. behavioural tests]. Lesion size was dramatically reduced and there was an increase of surviving neurons in the EODF animals. Additionally, there was an increase of corticospinal tract sprouting proximal and distal to the lesion site. The expression of trkB (receptor for BDNF) was changed both at, and distal to, the lesion site, which could play a role in both the neuroprotection and increased plasticity observed.Medicine, Faculty ofGraduat

Identification of mitophagy-related hub genes during the progression of spinal cord injury by integrated multinomial bioinformatics analysis

Spinal cord injury (SCI) is a disturbance of peripheral and central nerve conduction that causes disability in sensory and motor function. Currently, there is no effective treatment for SCI. Mitophagy plays a vital role in mitochondrial quality control during various physiological and pathological processes. The study aimed to elucidate the role of mitophagy and identify potential mitophagy-related hub genes in SCI pathophysiology. Two datasets (GSE15878 and GSE138637) were analyzed. Firstly, the differentially expressed genes (DEGs) were identified and mitophagy-related genes were obtained from GeneCards, then the intersection between SCI and mitophagy-related genes was determined. Next, we performed gene set enrichment analysis (GSEA), weighted gene co-expression network analysis (WGCNA), protein-protein interaction network (PPI network), least absolute shrinkage and selection operator (LASSO), and cluster analysis to identify and define the hub genes in SCI. Finally, the link between hub genes and infiltrating immune cells was investigated and the potential transcriptional regulation/small molecular compounds to target hub genes were predicted. In total, SKP1 and BAP1 were identified as hub genes of mitophagy-related DEGs during SCI development and regulatory T cells (Tregs)/resting NK cells/activated mast cells may play an essential role in the progression of SCI. LINC00324 and SNHG16 may regulate SKP1 and BAP1, respectively, through miRNAs. Eleven and eight transcriptional factors (TFs) regulate SKP1 and BAP1, respectively, and six small molecular compounds target BAP1. Then, the mRNA expression levels of BAP1 and SKP1 were detected in the injured sites of spinal cord of SD rats at 6 h and 72 h after injury using RT-qPCR, and found that the level were decreased. Therefore, the pathways of mitophagy are downregulated during the pathophysiology of SCI, and SKP1 and BAP1 could be accessible targets for diagnosing and treating SCI

Intermittent Fasting Improves Functional Recovery after Rat Thoracic Contusion Spinal Cord Injury

Spinal cord injury (SCI) often results in a loss of motor and sensory function. Currently there are no validated effective clinical treatments. Previously we found in rats that dietary restriction, in the form of every-other-day fasting (EODF), started prior to (pre-EODF), or after (post-EODF) an incomplete cervical SCI was neuroprotective, increased plasticity, and promoted motor recovery. Here we examined if EODF initiated prior to, or after, a T10 thoracic contusion injury would similarly lead to enhanced functional recovery compared to ad libitum feeding. Additionally, we tested if a group fed every day (pair-fed), but with the same degree of restriction as the EODF animals (∼25% calorie restricted), would also promote functional recovery, to examine if EODF's effect is due to overall calorie restriction, or is specific to alternating sequences of 24-h fasts and ad libitum eating periods. Behaviorally, both pre- and post-EODF groups exhibited better functional recovery in the regularity indexed BBB ambulatory assessment, along with several parameters of their walking pattern measured with the CatWalk device, compared to both the ad-libitium-fed group as well as the pair-fed group. Several histological parameters (intensity and symmetry of serotonin immunostaining caudal to the injury and gray matter sparing) correlated with functional outcome; however, no group differences were observed. Thus besides the beneficial effects of EODF after a partial cervical SCI, we now report that alternating periods of fasting (but not pair-fed) also promotes improved hindlimb locomotion after thoracic spinal cord contusion, demonstrating its robust effect in two different injury models

A Systematic Review of Directly Applied Biologic Therapies for Acute Spinal Cord Injury

An increasing number of therapies for spinal cord injury (SCI) are emerging from the laboratory and seeking translation into human clinical trials. Many of these are administered as soon as possible after injury with the hope of attenuating secondary damage and maximizing the extent of spared neurologic tissue. In this article, we systematically reviewed the available preclinical research on such neuroprotective therapies that are administered in a non-invasive manner for acute SCI. Specifically, we reviewed treatments that have a relatively high potential for translation due to the fact that they are already used in human clinical applications or are available in a form that could be administered to humans. These included: erythropoietin, NSAIDs, anti-CD11d antibodies, minocycline, progesterone, estrogen, magnesium, riluzole, polyethylene glycol, atorvastatin, inosine, and pioglitazone. The literature was systematically reviewed to examine studies in which an in vivo animal model was utilized to assess the efficacy of the therapy in a traumatic spinal cord injury paradigm. Using these criteria, 122 studies were identified and reviewed in detail. Wide variations exist in the animal species, injury models, and experimental designs reported in the preclinical literature on the therapies reviewed. The review highlights the extent of investigation that has occurred in these specific therapies, and points out gaps in our knowledge that would be potentially valuable prior to human translation

Ketogenic diet improves forelimb motor function after spinal cord injury in rodents.

High fat, low carbohydrate ketogenic diets (KD) are validated non-pharmacological treatments for some forms of drug-resistant epilepsy. Ketones reduce neuronal excitation and promote neuroprotection. Here, we investigated the efficacy of KD as a treatment for acute cervical spinal cord injury (SCI) in rats. Starting 4 hours following C5 hemi-contusion injury animals were fed either a standard carbohydrate based diet or a KD formulation with lipid to carbohydrate plus protein ratio of 3:1. The forelimb functional recovery was evaluated for 14 weeks, followed by quantitative histopathology. Post-injury 3:1 KD treatment resulted in increased usage and range of motion of the affected forepaw. Furthermore, KD improved pellet retrieval with recovery of wrist and digit movements. Importantly, after returning to a standard diet after 12 weeks of KD treatment, the improved forelimb function remained stable. Histologically, the spinal cords of KD treated animals displayed smaller lesion areas and more grey matter sparing. In addition, KD treatment increased the number of glucose transporter-1 positive blood vessels in the lesion penumbra and monocarboxylate transporter-1 (MCT1) expression. Pharmacological inhibition of MCTs with 4-CIN (α-cyano-4-hydroxycinnamate) prevented the KD-induced neuroprotection after SCI, In conclusion, post-injury KD effectively promotes functional recovery and is neuroprotective after cervical SCI. These beneficial effects require the function of monocarboxylate transporters responsible for ketone uptake and link the observed neuroprotection directly to the function of ketones, which are known to exert neuroprotection by multiple mechanisms. Our data suggest that current clinical nutritional guidelines, which include relatively high carbohydrate contents, should be revisited

3:1 ketogenic diet (3:1 KD) improved food pellet reaching as assessed with the Montoya staircase test (experiment 2).

<p>(A) C5 hemi-contusion injury produced marked impairments in reaching with the ipsilateral forelimb, as illustrated by decreased ability to retrieve pellets in the staircase test. However, at 6 wks post-injury 3:1 KD treated animals retrieved pellets twice as successful with the ipsilateral paw compared to animals fed SD. (B) Animals also displayed a decreased skilled reaching success with the paw contralateral to the lesion. No differences were observed between groups. (C) KD animals were more successful than SD animals in retrieving pellets from the lower wells. Error bars indicate SEM. * p ≤ 0.05 (t-test).</p

KD-induced neuroprotective effect is lost in when MCT transport is inhibited using α-cyano-4-hydroxy-cinnamate (4-CIN).

<p>At day 7-post injury, the total lesion volume (Cavalieri’s Estimator of Morphometric Volume) was decreased in spinal cords of KD fed animals compared to the standard diet group (SD). However, no difference in lesion volume between both groups was observed when animals were treated for 7 days with the MCT inhibitor 4-CIN. Error bars indicate SEM. # p=0.057 (t-test, one tailed).</p

Effect of 3:1 ketogenic diet (KD) on forelimb usage during grooming after C5 hemi-contusion (experiment 1).

<p>A. Scoring system used: Animal’s forepaw 0) was unable to contact any part of the face or head; 1) touched underside of chin and/or mouth area; 2) contacted area between nose and eyes, but not the eyes; 3) contacted eyes and area up to, but not including, the front of ears; an additional 0.5 score was given if the paw reached higher than half of the areas total length; 4) contacted front but not back of ears; 5) contacted area behind ears. (B) 3:1 KD treated rats demonstrated an increased grooming score, compared to SD animals. (C) After 14 wks of 3:1 ketogenic diet treatment (KD), we observed an improved forelimb range of motion compared to standard diet fed animals (SD). 66% of the KD animals reached up to the level of the eye (score 3). Most of the SD animals (88%) could only reach as far up as the nose (score 2). Error bars indicate SEM. * p=0.05 (Chi-square test).</p