Impact of intravenously administered cranial bone-derived mesenchymal stem cells on functional recovery in experimental spinal cord injury.

Impairments of the central nervous system, such as stroke, brain trauma, and spinal cord injury (SCI), cannot be reversed using current treatment options. Herein, we compared the characteristics of rat cranial bone-derived mesenchymal stem cells (rcMSCs) and rat bone marrow-derived mesenchymal stem cells (rbMSCs). We also investigated the therapeutic effects of intravenously administered rcMSCs and rbMSCs in a rat model of cervical SCI (cSCI) and elucidated its undrelying mechanism. Comprehensive comparative bioinformatics analysis of rcMSCs and rbMSCs RNA sequencing revealed that genes associated with leukocyte transendothelial migration and chemokine signaling were significantly downregulated in rcMSCs. Rats were divided into three groups that received intrtravenous administration of rcMSC, rbMSC, or phosphate-buffered saline (control) 24 h after cSCI. The rcMSC-treated group showed improved functional recovery over the rbMSC-treated and control groups, and reduced lesion volume compared with the control group. The mRNA expression of nitric oxide synthase 2 at the spinal cord lesion site was significantly higher in the rcMSC-treated group than in the control and rbMSCs-treated groups, whereas that of transforming growth factor-ß was significantly higher in the rcMSC-treated group compared to that in the control group. The transcriptome data indicated that rcMSCs and rbMSCs differentially affect inflammation. The intravenous administration of rcMSCs contributed to functional recovery and lesion reduction in cSCI. The rcMSCs have the potential to induce an anti-inflammatory environment in cSCI.

Motor and somatosensory degenerative myelopathy responsive to pantothenic acid in piglets.

This report describes 2 events of degenerative myelopathy in 4- to 27-day-old piglets, with mortality rates reaching 40%. Sows were fed rations containing low levels of pantothenic acid. Piglets presented with severe depression, weakness, ataxia, and paresis, which were more pronounced in the pelvic limbs. No significant gross lesions were observed. Histologically, there were degeneration and necrosis of neurons in the spinal cord, primarily in the thoracic nucleus in the thoracic and lumbar segments, and motor neurons in nucleus IX of the ventral horn in the cervical and lumbar intumescence. Minimal-to-moderate axonal and myelin degeneration was observed in the dorsal funiculus of the spinal cord and in the dorsal and ventral nerve roots. Immunohistochemistry demonstrated depletion of acetylcholine neurotransmitters in motor neurons and accumulation of neurofilaments in the perikaryon of neurons in the thoracic nucleus and motor neurons. Ultrastructurally, the thoracic nucleus neurons and motor neurons showed dissolution of Nissl granulation. The topographical distribution of the lesions indicates damage to the second-order neurons of the spinocerebellar tract, first-order axon cuneocerebellar tract, and dorsal column-medial lemniscus pathway as the cause of the conscious and unconscious proprioceptive deficit, and damage to the alpha motor neuron as the cause of the motor deficit. Clinical signs reversed and no new cases occurred after pantothenic acid levels were corrected in the ration, and piglets received parenteral administration of pantothenic acid. This study highlights the important and practical use of detailed neuropathological analysis to refine differential diagnosis.

Defined Alginate Hydrogels Support Spinal Cord Organoid Derivation, Maturation, and Modeling of Spinal Cord Diseases.

In the process of generating organoids, basement membrane extracts or Matrigel are often used to encapsulate cells but they are poorly defined and contribute to reproducibility issues. While defined hydrogels are increasingly used for organoid culture, the effects of replacing Matrigel with a defined hydrogel on neural progenitor growth, neural differentiation, and maturation within organoids are not well-explored. In this study, the use of alginate hydrogels as a Matrigel substitute in spinal cord organoid generation is explored. It is found that alginate encapsulation reduces organoid size variability by preventing organoid aggregation. Importantly, alginate supports neurogenesis and gliogenesis of the spinal cord organoids at a similar efficiency to Matrigel, with mature myelinated neurons observed by day 120. Furthermore, using alginate leads to lower expression of non-spinal markers such as FOXA2, suggesting better control over neural fate specification. To demonstrate the feasibility of using alginate-based organoid cultures as disease models, an isogenic pair of induced pluripotent stem cells discordant for the ALS-causing mutation TDP43G298S is used, where increased TDP43 mislocalization in the mutant organoids is observed. This study shows that alginate is an ideal substitute for Matrigel for spinal cord organoid derivation, especially when a xeno-free and fully defined 3D culture condition is desired.

Neuroinflammation and apoptosis after surgery for a rat model of double-level cervical cord compression.

INTRODUCTION: Cervical spondylotic myelopathy (CSM) is the most prevalent type of non-traumatic spinal cord injury. The pathological process of CSM is relatively complicated. Most of the chronic cervical cord compression animal models established using hydrophilic expanding polymer are single-segment compression, which was deviated from clinical practice with double-segment or multi-segment compression. This study aims to better mimic the actual clinical compression by using a new type of hydrophilic expanding polymer to establish an animal model of double-level cervical cord compression. MATERIALS AND METHODS: Progressive cord compression was done with implantation of polyvinyl alcohol-polyacrylamide hydrogel in the spinal canal at the C3-4 and C5-6 levels. Sprague-Dawley rats (n = 32) were divided into three groups: sham (no compression, n = 12) and screw compression group (n = 8), and hydrogel compression group (n = 12). Functional deficits were characterized using motor function scores, forelimb grip strength, hindlimb pain threshold, and gait analysis, while compression was imaged with magnetic resonance imaging. The apoptosis, inflammation, and demyelination were assessed by hematoxylin and eosin staining, Luxol fast blue staining, TUNEL assay, immunofluorescence staining, and Western blot analysis. RESULTS: Motor function scores for rats with cervical cord hydrogel compression were significantly decline in motor function scores, an increase in allodynia, neurons and oligodendrocytes apoptosis related to B cell lymphoma-2 (Bcl-2)/Bcl-2 associated X (Bax)/cleaved caspase-3, and impaired axonal conduction, as well as neuroinflammation zone related to microglia or macrophages aggregation related to the nucleotide-binding domain, leucine-rich-repeat-containing family, pyrin domain-containing 3 (NLRP3) inflammasome activation, and activation of astrocytes, as well as oxidative stress were observed. CONCLUSION: We believe that this model utilizing compression on double-level cervical cord will allow researchers to investigate of translationally relevant therapeutic methods for CSM.

Fatty infiltration in cervical flexors and extensors in patients with degenerative cervical myelopathy using a multi-muscle segmentation model.

BACKGROUND: In patients with degenerative cervical myelopathy (DCM) that have spinal cord compression and sensorimotor deficits, surgical decompression is often performed. However, there is heterogeneity in clinical presentation and post-surgical functional recovery. OBJECTIVES: Primary: a) to assess differences in muscle fat infiltration (MFI) in patients with DCM versus controls, b) to assess association between MFI and clinical disability. Secondary: to assess association between MFI pre-surgery and post-surgical functional recovery. STUDY DESIGN: Cross-sectional case control study. METHODS: Eighteen patients with DCM (58.6 ± 14.2 years, 10 M/8F) and 25 controls (52.6 ± 11.8 years, 13M/12 F) underwent 3D Dixon fat-water imaging. A convolutional neural network (CNN) was used to segment cervical muscles (MFSS- multifidus and semispinalis cervicis, LC- longus capitis/colli) and quantify MFI. Modified Japanese Orthopedic Association (mJOA) and Nurick were collected. RESULTS: Patients with DCM had significantly higher MFI in MFSS (20.63 ± 5.43 vs 17.04 ± 5.24, p = 0.043) and LC (18.74 ± 6.7 vs 13.66 ± 4.91, p = 0.021) than controls. Patients with increased MFI in LC and MFSS had higher disability (LC: Nurick (Spearman's ρ = 0.436, p = 0.003) and mJOA (ρ = -0.399, p = 0.008)). Increased MFI in LC pre-surgery was associated with post-surgical improvement in Nurick (ρ = -0.664, p = 0.026) and mJOA (ρ = -0.603, p = 0.049). CONCLUSION: In DCM, increased muscle adiposity is significantly associated with sensorimotor deficits, clinical disability, and functional recovery after surgery. Accurate and time efficient evaluation of fat infiltration in cervical muscles may be conducted through implementation of CNN models.

A report of two cases of bulbospinal form Alexander disease and preliminary exploration of the disease.

Alexander disease (AxD) is a cerebral white matter disease affecting a wide range of ages, from infants to adults. In the present study, two cases of bulbospinal form AxD were reported, and a preliminary exploration of AxD was conducted thorough clinical, functional magnetic resonance imaging (fMRI) and functional analyses. In total, two de novo mutations in the glial fibrillary acidic protein (GFAP) gene (c.214G>A and c.1235C>T) were identified in unrelated patients (one in each patient). Both patients showed increased regional neural activity and functional connectivity in the cerebellum and posterior parietal cortex according to fMRI analysis. Notably, grey matter atrophy was discovered in the patient with c.214G>A variant. Functional experiments revealed aberrant accumulation of mutant GFAP and decreased solubility of c.1235C>T variant. Under pathological conditions, autophagic flux was activated for GFAP aggregate degradation. Moreover, transcriptional data of AxD and healthy human brain samples were obtained from the Gene Expression Omnibus database. Gene set enrichment analysis revealed an upregulation of immune­related responses and downregulation of ion transport, synaptic transmission and neurotransmitter homeostasis. Enrichment analysis of cell­specific differentially expressed genes also indicated a marked inflammatory environment in AxD. Overall, the clinical features of the two patients with bulbospinal form AxD were thoroughly described. To the best of our knowledge, the brain atrophy pattern and spontaneous brain functional network activity of patients with AxD were explored for the first time. Cytological experiments provided evidence of the pathogenicity of the identified variants. Furthermore, bioinformatics analysis found that inflammatory immune­related reactions may play a critical role in AxD, which may be conducive to the understanding of this disease.

Downregulation of microRNA-199a-5p alleviated lidocaine-induced sensory dysfunction and spinal cord myelin lesions in a rat model.

Lidocaine induces neurotoxicity in the spinal cord, but the underlying mechanisms remain unclear. In this study, we evaluated the effects of miR-199a-5p on 10 % lidocaine neurotoxicity. Increased expression of miR-199a-5p in the spinal cord of rats treated with 10 % lidocaine was assessed by qRT-PCR. Furthermore, after miR-199a-5p antagomir administration, the sensory dysfunction and myelin sheath lesions (evaluated by semithin sections stained with toluidine blue, electron microscopy, g-ratios and myelin thickness) induced by 10 % lidocaine were alleviated. Myelin regulatory factor (MYRF), a key molecule of myelin sheath development, was predicted to be a target gene of miR-199a-5p by the TargetScan and miRBase databases. MYRF and its downstream factors myelin basic protein (MBP), proteolipid protein (PLP) and myelin oligodendrocyte glycoprotein (MOG) were significantly decreased after intrathecal 10 % lidocaine administration. Moreover, these changes were reversed after miR-199a-5p antagomir administration. FISH-immunofluorescence showed coexpression of miR-199a-5p and MYRF in the spinal cord white matter of rats. A luciferase reporter assay further demonstrated the functional association between miR-199a-5p and MYRF. Overall, miR-199a-5p upregulation is involved in 10 % lidocaine-induced spinal cord toxicity through regulation of MYRF. Therefore, downregulating miR-199a-5p expression may be a potential strategy to ameliorate spinal cord neurotoxicity induced by 10 % lidocaine.

Up-regulated inflammatory signatures of the spinal cord in canine degenerative myelopathy.

Canine degenerative myelopathy (DM) is an adult-onset fatal disease characterized by progressive degeneration of the spinal cord. Affected dogs have homozygous mutations in superoxide dismutase 1, and thus DM is a potential spontaneous animal model of human familial amyotrophic lateral sclerosis (ALS). Neuroinflammation is the pathological hallmark of ALS, whereby proinflammatory cytokines and chemokines are overproduced by activated glial cells such as astrocytes and microglia. However, the detailed pathogenesis of spinal cord degeneration in DM remains unknown. To further characterize the pathological mechanism of DM, we analyzed the caudal cervical cords of ten Pembroke Welsh Corgis pathologically diagnosed with DM by quantitative real-time reverse transcription polymerase chain reaction, immunohistochemistry (IHC), and double immunofluorescence. Compared to control spinal cord tissues, we found significantly enhanced transcriptions of interleukin-1ß, tumor necrosis factor-α, CC motif chemokine ligand (CCL) 2 and vascular cell adhesion molecule -1 mRNA in the spinal cords of DM dogs. Moreover, IHC for the class II major histocompatibility complex molecules HLA-DR and CCL2 indicated that the immunopositive areas of activated macrophages/microglia and CCL2 protein were significantly increased in DM, and CCL2 protein was mainly overproduced by astrocytes. Our results suggest a proinflammatory state of the microenvironment in the DM spinal cord in which activated microglia and astrocytes play important roles by secreting a set of cytokines, chemokines, and expressing adhesion molecules.

Spinal muscular atrophy type III complicated by spinal superficial siderosis: a case report with molecular and neuropathological findings.

Spinal muscular atrophy (SMA) is largely linked to deletion or mutation of the Survival motor neuron 1 (SMN1) gene located on chromosome 5q13. Type III (Kugelberg-Welander disease) is the mildest childhood form and patients may become ambulatory and have a normal life expectancy. We report the clinical history and morphological findings of a 55-year-old woman who began to experience motor problems at the age of two. She was never fully ambulatory, and her severe scoliosis required the insertion of surgical rod at age 19. Unexpectedly, around 35 years of age, she began to experience sensory symptoms best characterized as a myelo-radiculo-neuropathy with pain as the dominant symptom. Investigations never clarified the etiology of these symptoms. Molecular confirmation of SMA type III was done post-mortem. Neuropathological examination showed classic changes of lower motor neuron neurodegeneration, in line with those reported in the single molecularly confirmed case published so far, and with findings in rare cases reported prior to the discovery of the gene defect. A key autopsy finding was the presence of a severe superficial siderosis of the lower half of the spinal cord. In recent years, the concept of duropathy was put forward, associating superficial siderosis of the spinal cord with various spinal abnormalities, some of which were present in our patient. The presence of significant hemosiderin deposits in the spinal cord and sensory nerve roots with associated tissue and axonal damage provide a plausible explanation for the unexpected sensory symptomatology in this mild lower motor neurodegeneration.

Plasma NfL and GFAP as biomarkers of spinal cord degeneration in adrenoleukodystrophy.

OBJECTIVE: To explore the potential of neurofilament light (NfL) and glial fibrillary acidic protein (GFAP) as biomarkers of spinal cord degeneration in adrenoleukodystrophy, as objective treatment-outcome parameters are needed. METHODS: Plasma NfL and GFAP levels were measured in 45 male and 47 female ALD patients and compared to a reference cohort of 73 healthy controls. For male patients, cerebrospinal fluid (CSF) samples (n = 33) and 1-year (n = 39) and 2-year (n = 18) follow-up data were also collected. Severity of myelopathy was assessed with clinical parameters: Expanded Disability Status Scale (EDSS), Severity Scoring system for Progressive Myelopathy (SSPROM), and timed up-and-go. RESULTS: NfL and GFAP levels were higher in male (P < 0.001, effect size (partial ƞ2 ) NfL = 0.49, GFAP = 0.13) and female (P < 0.001, effect size NfL = 0.19, GFAP = 0.23) patients compared to controls; levels were higher in both symptomatic and asymptomatic patients. In male patients, NfL levels were associated with all three clinical parameters of severity of myelopathy (EDSS, SSPROM, and timed up-and go), while GFAP in male and NfL and GFAP in female patients were not. Changes in clinical parameters during follow-up did not correlate with (changes in) NfL or GFAP levels. Plasma and CSF NfL were strongly correlated (r = 0.60, P < 0.001), but plasma and CSF GFAP were not (r = 0.005, P = 0.98). INTERPRETATION: Our study illustrates the potential of plasma NfL as biomarker of spinal cord degeneration in adrenoleukodystrophy, which was superior to plasma GFAP in our cohort.

Zonisamide ameliorates progression of cervical spondylotic myelopathy in a rat model.

Cervical spondylotic myelopathy (CSM) is caused by chronic compression of the spinal cord and is the most common cause of myelopathy in adults. No drug is currently available to mitigate CSM. Herein, we made a rat model of CSM by epidurally implanting an expanding water-absorbent polymer underneath the laminae compress the spinal cord. The CSM rats exhibited progressive motor impairments recapitulating human CSM. CSM rats had loss of spinal motor neurons, and increased lipid peroxidation in the spinal cord. Zonisamide (ZNS) is clinically used for epilepsy and Parkinson's disease. We previously reported that ZNS protected primary spinal motor neurons against oxidative stress. We thus examined the effects of ZNS on our rat CSM model. CSM rats with daily intragastric administration of 0.5% methylcellulose (n = 11) and ZNS (30 mg/kg/day) in 0.5% methylcellulose (n = 11). Oral administration of ZNS ameliorated the progression of motor impairments, spared the number of spinal motor neurons, and preserved myelination of the pyramidal tracts. In addition, ZNS increased gene expressions of cystine/glutamate exchange transporter (xCT) and metallothionein 2A in the spinal cord in CSM rats, and also in the primary astrocytes. ZNS increased the glutathione (GSH) level in the spinal motor neurons of CSM rats. ZNS potentially ameliorates loss of the spinal motor neurons and demyelination of the pyramidal tracts in patients with CSM.

The protective effort of GPCR kinase 2-interacting protein-1 in neurons via promoting Beclin1-Parkin induced mitophagy at the early stage of spinal cord ischemia-reperfusion injury.

In spinal cord ischemia-reperfusion (I/R) injury, large amounts of reactive oxygen species can cause mitochondrial damage. Therefore, mitophagy acts as the main mechanism for removing damaged mitochondria and protects nerve cells. This study aimed to illustrate the important role of GPCR kinase 2-interacting protein-1 (GIT1) in mitophagy in vivo and in vitro. The level of mitophagy in the neurons of Git1 knockout mice was significantly reduced after ischemia-reperfusion. However, the overexpression of adeno-associated virus with Git1 promoted mitophagy and inhibited the apoptosis of neurons. GIT1 regulated the phosphorylation of Beclin-1 in Thr119, which could promote the translocation of Parkin to the mitochondrial outer membrane. This process was independent of PTEN-induced kinase 1 (PINK1), but it could not rescue the role in the absence of PINK1. Overall, GIT1 enhanced mitophagy and protected neurons against ischemia-reperfusion injury and, hence, might serve as a new research site for the protection of ischemia-reperfusion injury.

Simulated microgravity-cultured mesenchymal stem cells improve recovery following spinal cord ischemia in rats.

Spinal cord ischemia is a potential complication of thoracoabdominal aortic surgery that may induce irreversible motor disability. We investigated the therapeutic efficacy of simulated microgravity-cultured mesenchymal stem cell (MSC) injection following spinal cord ischemia-reperfusion injury. Sprague-Dawley rats were divided into sham, phosphate-buffered saline (PBS), normal gravity-cultured MSC (MSC-1 G), and simulated microgravity-cultured MSC (MSC-MG) groups. Spinal cord ischemia was induced by transient balloon occlusion of the thoracic aorta, which was followed immediately by PBS or MSC injection into the left carotid artery. Hindlimb motor function was evaluated by the Basso-Beattie-Bresnahan (BBB) scale. Spinal cords were removed 1, 3, or 7 days post-injury for immunohistochemical staining and Western blot analysis. One day post-injury, a few infiltrating inflammatory cells and small vacuoles were observed without significant group differences, followed over several days by progressive spinal cord degeneration. Glial fibrillary acidic protein (GFAP)-positive (reactive) astrocyte numbers were increased in all three groups, and brain-derived neurotrophic factor (BDNF) was colocalized with GFAP-positive cells in spinal ventral horn. Animals in the MSC-MG group demonstrated greater BDNF-positive astrocyte numbers, reduced caspase-3-positive cell numbers, and superior motor recovery. Microgravity-cultured MSC-based therapy may improve functional recovery following spinal ischemia-reperfusion injury by promoting astrocytic BDNF release, thereby preventing apoptosis.

Jingshu Keli and its Components Notoginsenoside R1 and Ginsenoside Rb1 Alleviate the Symptoms of Cervical Myelopathy through Kir3.1 Mediated Mechanisms.

BACKGROUND & OBJECTIVE: Cervical Spondylotic Myelopathy (CSM) is one of the most serious spinal cord disorders in adults. Pharmacological modulation of ion channels is a common strategy to interfere with CSM and prevent neuronal damage. METHODS: Here, we investigated the effects of Jingshu Keli (JSKL), a traditional Chinese herbal formula, on CSM-related gait abnormality, mechanical allodynia and thermal hyperalgesia, and assessed the neuronal mechanisms of JSKL on cultured brainstem cells. Behavioral tests and patch clamp recordings were performed to make this assessment. RESULTS: In our study, we found that JSKL significantly recovered the gait performance (P<0.001) and decreased the levels of mechanical pain in 18.9% (P<0.01) and thermal pain in 18.1% (P<0.05). Further investigation suggested that JSKL and its containing ginsenoside Rb1 (GRb1), notoginsenoside R1 (NGR1) reduced the action potential frequency in 38.5%, 27.2%, 25.9%, and hyperpolarized resting membrane potential in 15.0%, 13.8%, 12.1%, respectively. Kir channels, not KV channels and KCa channels, were the major intermediate factors achieving treatment effects. Finally, immunostaining results showed that the phosphorylation of Kir3.1 was promoted, whereas the total expression level did not change. CONCLUSION: Our study reveals a novel strategy of treating CSM by using Traditional Chinese Medicines (TCMs) containing active components.

Towards prognostic functional brain biomarkers for cervical myelopathy: A resting-state fMRI study.

Recently, there has been increasing interest in strategies to predict neurological recovery in cervical myelopathy (CM) based on clinical images of the cervical spine. In this study, we aimed to explore potential preoperative brain biomarkers that can predict postoperative neurological recovery in CM patients by using resting-state functional magnetic resonance imaging (rs-fMRI) and functional connectivity (FC) analysis. Twenty-eight patients with CM and 28 age- and sex-matched healthy controls (HCs) underwent rs-fMRI (twice for CM patients, before and six months after surgery). A seed-to-voxel analysis was performed, and the following three statistical analyses were conducted: (i) FC comparisons between preoperative CM and HC; (ii) correlation analysis between preoperative FCs and clinical scores; and (iii) postoperative FC changes in CM. Our analyses identified three FCs between the visual cortex and the right superior frontal gyrus based on the conjunction of the first two analyses [(i) and (ii)]. These FCs may act as potential biomarkers for postoperative gain in the 10-second test and might be sufficient to provide a prediction formula for potential recovery. Our findings provide preliminary evidence supporting the possibility of novel predictive measures for neurological recovery in CM using rs-fMRI.

Cervical spondylotic myelopathy: Changes of fractional anisotropy in the spinal cord and magnetic resonance spectroscopy of the primary motor cortex in relation to clinical symptoms and their duration.

OBJECTIVE: To determine the changes in fractional anisotropy (FA) at the proximal spinal cord and in magnetic resonance spectroscopy (MRS) of the precentral gyrus in patients with cervical spondylotic myelopathy (CSM) with respect to clinical symptoms and their duration. MATERIAL AND METHODS: 20 patients with CSM (7 female; mean age 64.6 ± 10.5 years) and 18 age/sex matched healthy controls (9 female; mean age 63.5 ± 6.6 years) were prospectively included. Clinical data (modified Japanese Orthopaedic Association Score (mJOA) and Neck Disability Index (NDI)) and 3T MR measurements including DTI at the spinal cord (level C2/3) with FA and MRS of the left and right precentral gyrus were taken. Clinical correlations and regression analyses were performed. RESULTS: Mean clinical scores of patients were significantly different to controls (mJOA; CSM: 10.2 ± 2.9; controls: 18.0 ± 0.0, p < 0.001; NDI; CSM: 41.4±23.5; controls: 4.4±6.6, p<0.001); FA was significantly lower in patients (CSM: 0.645 ± 0.067; controls: 0.699 ± 0.037, p = 0.005). MRS showed significantly lower metabolite concentrations between both groups: creatine (Cr) (CSM: 46.46±7.64; controls: 51.36±5.76, p = 0.03) and N-acetylaspartate (NAA) (CSM: 93.94±19.22; controls: 107.24±20.20, p = 0.05). Duration of symptoms ≤6 months was associated with increased myo-inositol (Ins) (61.58±17.76; 44.44±10.79; p = 0.02) and Ins/Cr ratio (1.36±0.47; 0.96±0.18; p = 0.014) compared to symptoms >6 months. CONCLUSION: Metabolic profiles of the precentral gyrus and FA in the uppermost spinal cord differ significantly between patients and healthy controls. Ins, thought to be a marker of endogenous neuroinflammatory response, is high in the early course of CSM and normalizes over time.

Protein disulphide isomerase is associated with mutant SOD1 in canine degenerative myelopathy.

Canine degenerative myelopathy (DM) is a fatal neurodegenerative disorder prevalent in the canine population. It may represent a unique, naturally occurring disease model for human amyotrophic lateral sclerosis (ALS) because of similar clinical signs and association with superoxide dismutase 1 gene (SOD1) mutations. Misfolded SOD1 aggregates and endoplasmic reticulum (ER) stress are major pathophysiological features associated with ALS. Interestingly, an ER foldase, protein disulphide isomerase (PDI) is upregulated during ALS and it co-localizes with SOD1 inclusions in ALS patient tissues. Furthermore, mutations in the gene encoding PDI were recently associated with ALS. Given the genetic similarity between DM and ALS, we investigated whether ER stress and PDI were associated with DM. Protein extracts from spinal cord tissue of DM-affected dogs bearing a SOD1 mutation were examined for ER stress by western blotting. Immunohistochemical staining was also carried out to examine co-localization between endogenous PDI and SOD1 inclusions in spinal cord tissues of dogs affected with DM. PDI and CHOP, the proapoptotic protein induced during ER stress, were significantly upregulated in DM-affected dogs compared with controls. Furthermore, PDI co-localized with intracellular SOD1 aggregates in DM-affected dogs in all motor neurons examined, indicating that PDI may be a cellular defence mechanism against SOD1 misfolding in DM. Our results imply that ER stress is induced in DM-affected dogs; hence, it is a common pathological mechanism associated with both ALS and DM. The possibility that PDI may be a therapeutic target to inhibit SOD1 aggregation in DM dogs is also raised by this study.

Spinal cord involvement in adult-onset metabolic and genetic diseases.

In adulthood, spinal cord MRI abnormalities such as T2-weighted hyperintensities and atrophy are commonly associated with a large variety of causes (inflammation, infections, neoplasms, vascular and spondylotic diseases). Occasionally, they can be due to rare metabolic or genetic diseases, in which the spinal cord involvement can be a prominent or even predominant feature, or a secondary one. This review focuses on these rare diseases and associated spinal cord abnormalities, which can provide important but over-ridden clues for the diagnosis. The review was based on a PubMed search (search terms: 'spinal cord' AND 'leukoencephalopathy' OR 'leukodystrophy'; 'spinal cord' AND 'vitamin'), further integrated according to the authors' personal experience and knowledge. The genetic and metabolic diseases of adulthood causing spinal cord signal alterations were identified and classified into four groups: (1) leukodystrophies; (2) deficiency-related metabolic diseases; (3) genetic and acquired toxic/metabolic causes; and (4) mitochondrial diseases. A number of genetic and metabolic diseases of adulthood causing spinal cord atrophy without signal alterations were also identified. Finally, a classification based on spinal MRI findings is presented, as well as indications about the diagnostic work-up and differential diagnosis. Some of these diseases are potentially treatable (especially if promptly recognised), while others are inherited as autosomal dominant trait. Therefore, a timely diagnosis is needed for a timely therapy and genetic counselling. In addition, spinal cord may be the main site of pathology in many of these diseases, suggesting a tempting role for spinal cord abnormalities as surrogate MRI biomarkers.

Activation of the unfolded protein response in canine degenerative myelopathy.

Canine degenerative myelopathy (DM) is an adult-onset progressive and fatal neurodegenerative disorder. Superoxide dismutase 1 (SOD1) mutations have been reported in affected dogs and immunohistochemical analyses revealed the accumulation of mutant SOD1 (E40K) in spinal neurons and astrocytes. Therefore, this disease is regarded as a unique spontaneous large-animal model of SOD1-mediated amyotrophic lateral sclerosis (ALS) in humans. Recent studies reported that endoplasmic reticulum (ER) stress is a key pathomechanism underlying motor neuron death in ALS. The present study demonstrated the up-regulated expression of the ER stress marker GRP78/BiP (BiP) in the spinal cords of DM-affected dogs. Immunohistochemistry of serial spinal cord sections revealed strong BiP expression in microglia and astrocytes in DM compared to normal control dogs, whereas such difference was not observed in spinal neurons. The results of transcriptional analyses of DM spinal tissues showed increased expression levels of apoptosis signal-regulating kinase 1 (ASK1) and spliced X-box binding protein (XBP1s). E40K-transfected Neuro2A cells expressed higher levels of BiP than wild-type SOD1-transfected cells. These results suggest that the activation of the unfolded protein response (UPR) in microglia and astrocytes plays crucial roles in UPR-mediated inflammation in the spinal cords of DM-affected dogs.

Effects of aquaporin 4 and inward rectifier potassium channel 4.1 on medullospinal edema after methylprednisolone treatment to suppress acute spinal cord injury in rats.

PURPOSE: To investigate the effects of aquaporin 4 (AQP4) and inward rectifier potassium channel 4.1 (Kir4.1) on medullospinal edema after treatment with methylprednisolone (MP) to suppress acute spinal cord injury (ASCI) in rats. METHODS: Sprague Dawley rats were randomly divided into control, sham, ASCI, and MP-treated ASCI groups. After the induction of ASCI, we injected 30 mg/kg MP via the tail vein at various time points. The Tarlov scoring method was applied to evaluate neurological symptoms, and the wet-dry weights method was applied to measure the water content of the spinal cord. RESULTS: The motor function score of the ASCI group was significantly lower than that of the sham group, and the spinal water content was significantly increased. In addition, the levels of AQP4 and Kir4.1 were significantly increased, as was their degree of coexpression. Compared with that in the ASCI group, the motor function score and the water content were significantly increased in the MP group; in addition, the expression and coexpression of AQP4 and Kir4.1 were significantly reduced. CONCLUSION: Methylprednisolone inhibited medullospinal edema in rats with acute spinal cord injury, possibly by reducing the coexpression of aquaporin 4 and Kir4.1 in medullospinal tissues.