Mesenchymal stem cells (MSC) derived from bone marrow can potentially reduce the acute inflammatory response in spinal cord injury (SCI) and thus promote functional recovery. However, the precise ...mechanisms through which transplanted MSC attenuate inflammation after SCI are still unclear. The present study was designed to investigate the effects of MSC transplantation with a special focus on their effect on macrophage activation after SCI. Rats were subjected to T9-T10 SCI by contusion, then treated 3 days later with transplantation of 1.0×10(6) PKH26-labeled MSC into the contusion epicenter. The transplanted MSC migrated within the injured spinal cord without differentiating into glial or neuronal elements. MSC transplantation was associated with marked changes in the SCI environment, with significant increases in IL-4 and IL-13 levels, and reductions in TNF-α and IL-6 levels. This was associated simultaneously with increased numbers of alternatively activated macrophages (M2 phenotype: arginase-1- or CD206-positive), and decreased numbers of classically activated macrophages (M1 phenotype: iNOS- or CD16/32-positive). These changes were associated with functional locomotion recovery in the MSC-transplanted group, which correlated with preserved axons, less scar tissue formation, and increased myelin sparing. Our results suggested that acute transplantation of MSC after SCI modified the inflammatory environment by shifting the macrophage phenotype from M1 to M2, and that this may reduce the effects of the inhibitory scar tissue in the subacute/chronic phase after injury to provide a permissive environment for axonal extension and functional recovery.
Spinal cord injury (SCI) is a devastating lesion lacking effective treatment options currently available in clinics. The inflammatory process exacerbates the extent of the lesion through a secondary ...injury mechanism, where proinflammatory classically activated macrophages (M1) are prevalent at the lesion site. However, the polarized alternatively activated anti-inflammatory macrophages (M2) are known to play an important role in wound healing and regeneration following SCI. Herein, we introduce porcine brain decellularized extracellular matrix (dECM) to modulate the macrophages in the injured spinal cord. The hydrogels with collagen and dECM at various dECM concentrations (1, 5, and 8 mg/ml) were used to cultivate primary macrophages and neurons. The dECM hydrogels were shown to promote the polarization of macrophages toward M2 phase and the neurite outgrowth of cortical and hippocampal neurons. When the dECM hydrogels were applied to rat SCI models, the proportion of M1 and M2 macrophages in the injured spinal cord was substantially altered. When received dECM concetration of 5 mg/ml, the expression of molecules associated with M2 (CD206, arginase1, and IL-10) was significantly increased. Consistently, the population of total macrophages and cavity area were substantially reduced in the dECM-treated groups. As a result, the locomotor functions of injured spinal cord, as assessed by BBB and ladder scoring, were significantly improved. Collectively, the porcine brain dECM with optimal concentration promotes functional recovery in SCI models through the activation of M2 macrophages, suggesting the promising use of the engineered hydrogels in the treatment of acute SCI.
Spinal cord injury (SCI) is a devastating lesion, lacking effective treatment options currently available in clinics. Here we delineated that the treatment of injured spinal cord with porcine brain decellularized matrix-based hydrogels for the first time, and could modulate the macrophage polarization and the ultimate functional recovery. When appropriate formulations were applied to a contused spinal cord model in rats, the decellularized matrix hydrogels shifted the macrophages to polarize to pro-regenerative M2 phenotype, decreased the size of lesion cavity, and finally promoted the locomotor functions until 8 weeks following the injury. We consider this work can significantly augment the matrix(biomaterial)-based therapeutic options, as an alternative to drug or cell-free approaches, for the treatment of acute injury of spinal cord.
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Axonal regeneration and formation of tripartite (axo-glial) junctions at damaged sites is a prerequisite for early repair of injured spinal cord. Transplantation of stem cells at such sites of damage ...which can generate both neuronal and glial population has gained impact in terms of recuperation upon infliction with spinal cord injury. In spite of the fact that a copious number of pre-clinical studies using different stem/progenitor cells have shown promising results at acute and subacute stages, at the chronic stages of injury their recovery rates have shown a drastic decline. Therefore, developing novel therapeutic strategies are the need of the hour in order to assuage secondary morbidity and effectuate improvement of the spinal cord injury (SCI)-afflicted patients’ quality of life. The present review aims at providing an overview of the current treatment strategies and also gives an insight into the potential cell-based therapies for the treatment of SCI.
To describe the prevalence of secondary health conditions among persons with long-term spinal cord injury, and the relationship between these secondary health conditions and quality of life.
...Multicentre, cross-sectional study.
Individuals (n = 282) with traumatic or non-traumatic spinal cord injury for ≥ 10 years, age at injury 18-35 years, current age 28-65 years, and using a wheelchair.
Occurrence of 13 secondary health conditions was assessed during a consultation with a rehabilitation physician. Quality of life was measured with the International Spinal Cord Injury Quality of Life Basic Data Set.
Median time since injury was 22.0 years. Median number of secondary health conditions was 4. The most prevalent secondary health conditions were: musculoskeletal pain (63.5%), oedema (38.7%), neuropathic pain (34.1%) and urinary tract infections (33.3%). Only oedema showed a significant association with increasing time since injury. Median Total Quality of Life Basic Data Set score was 7. Musculoskeletal pain, pressure ulcers, problematic spasticity and constipation showed an independent association with quality of life in multiple regression analysis, but in general, these associations were weak.
Secondary health conditions are common among persons with long-term spinal cord injury and the following secondary health conditions were independently associated with lower quality of life: musculoskeletal pain, pressure ulcers, problematic spasticity, and constipation. Minimizing the impact of secondary health conditions should be a priority in the long-term care of persons with spinal cord injury.
Neurologic impairment after spinal cord injury (SCI) is currently measured and classified by functional examination. Biological markers that objectively classify injury severity and predict outcome ...would greatly facilitate efforts to evaluate acute SCI therapies. The purpose of this study was to determine how well inflammatory and structural proteins within the cerebrospinal fluid (CSF) of acute traumatic SCI patients predicted American Spinal Injury Association Impairment Scale (AIS) grade conversion and motor score improvement over 6 months. Fifty acute SCI patients (29 AIS A, 9 AIS B, 12 AIS C; 32 cervical, 18 thoracic) were enrolled and CSF obtained through lumbar intrathecal catheters to analyze interleukin (IL)-6, IL-8, monocyte chemotactic protein (MCP)-1, tau, S100β, and glial fibrillary acidic protein (GFAP) at 24 h post-injury. The levels of IL-6, tau, S100β, and GFAP were significantly different between patients with baseline AIS grades of A, B, or C. The levels of all proteins (IL-6, IL-8, MCP-1, tau, S100β, and GFAP) were significantly different between those who improved an AIS grade over 6 months and those who did not improve. Linear discriminant analysis modeling was 83% accurate in predicting AIS conversion. For AIS A patients, the concentrations of proteins such as IL-6 and S100β correlated with conversion to AIS B or C. Motor score improvement also was strongly correlated with the 24-h post-injury CSF levels of all six biomarkers. The analysis of CSF can provide valuable biological information about injury severity and recovery potential after acute SCI. Such biological markers may be valuable tools for stratifying individuals in acute clinical trials where variability in spontaneous recovery requires large recruitment cohorts for sufficient power.
Ketogenic diet (KD) has been shown to be beneficial in a range of neurological disorders, with ketone metabolite β-hydroxybutyrate (βOHB) reported to block the nucleotide oligomerization domain-like ...receptor family, pyrin domain containing 3 (NLRP3) inflammasome in bone marrow-derived macrophages. In this study, we show that pretreatment with KD or
in situ
βOHB suppressed macrophages/microglia activation and the overproduction of inflammatory cytokines, while KD downregulated the expression of NLRP3 inflammasome. Moreover, KD promoted macrophages/microglia transformation from the M1 phenotype to the M2a phenotype following spinal cord injury (SCI) in the
in vivo
study. Rats in the KD group demonstrated improved behavioral and electrophysiological recovery after SCI when compared to those rats in the standard diet group. The
in vitro
study performed on BV2 cells indicated that βOHB inhibited an LPS+ATP-induced inflammatory response and decreased NLRP3 protein levels. Our data demonstrated that pretreatment with KD attenuated neuroinflammation following SCI, probably by inhibiting NLRP3 inflammasome and shifting the activation state of macrophages/microglia from the M1 to the M2a phenotype. Therefore, the ketone metabolite βOHB might provide a potential future therapeutic strategy for SCI.
Biomarkers of acute human spinal cord injury (SCI) could provide a more objective measure of spinal cord damage and a better predictor of neurological outcome than current standardized neurological ...assessments. In SCI, there is growing interest in establishing biomarkers from cerebrospinal fluid (CSF) and from magnetic resonance imaging (MRI). Here, we compared the ability of CSF and MRI biomarkers to classify injury severity and predict neurological recovery in a cohort of acute cervical SCI patients. CSF samples and MRI scans from 36 acute cervical SCI patients were examined. From the CSF samples taken 24 h post-injury, the concentrations of inflammatory cytokines (interleukin IL-6, IL-8, monocyte chemotactic protein-1), and structural proteins (tau, glial fibrillary acidic protein, and S100β) were measured. From the pre-operative MRI scans, we measured intramedullary lesion length, hematoma length, hematoma extent, CSF effacement, cord expansion, and maximal spinal cord compression. Baseline and 6-month post-injury assessments of American Spine Injury Association Impairment Scale (AIS) grade and motor score were conducted. Both MRI measures and CSF biomarker levels were found to correlate with baseline injury grade, and in combination they provided a stronger model for classifying baseline AIS grade than CSF or MRI biomarkers alone. For predicting neurological recovery, the inflammatory CSF biomarkers best predicted AIS grade conversion, whereas structural biomarker levels best predicted motor score improvement. A logistic regression model utilizing CSF biomarkers alone had a 91.2% accuracy at predicting AIS conversion, and was not strengthened by adding MRI features or even knowledge of the baseline AIS grade. In a direct comparison of MRI and CSF biomarkers, the CSF biomarkers discriminate better between different injury severities, and are stronger predictors of neurological recovery in terms of AIS grade and motor score improvement. These findings demonstrate the utility of measuring the acute biological responses to SCI as biomarkers of injury severity and neurological prognosis.
Spinal cord injury (SCI) usually affects younger age groups with male preponderance. The most common traumatic cause is road traffic accident followed by sports accidents and gun-shot injuries. ...Infections and vascular events make up non-traumatic causes. There is regional variance in incidence and prevalence of SCI. Most systematic reviews have been undertaken from USA, Canada, and Australia with only few from Asia with resultant difficulty in estimation of worldwide figures. Overall, the incidence varies from 12 to more than 65 cases/million per year. The first peak is in young men between 15 and 29 years and second peak in older adults. The average age at injury is 40 years, with commonest injury being incomplete tetraplegia followed by complete paraplegia, complete tetraplegia, and incomplete paraplegia. The bladder function is reliant on both central and peripheral nervous systems for co-ordination of storage and voiding phases. The pathophysiology of bladder dysfunction can be described as an alteration in micturition reflex. It is postulated that a new spinal reflex circuit develops which is mediated by C fibers as response to reorganization of synaptic connections in spinal cord. This is responsible for the development of neurogenic detrusor overactivity (NDO). Various neurotrophic hormones like nerve growth factor affect the morphological and physiological changes of the bladder afferent neurons leading to neuropathic bladder dysfunction. A suprasacral SCI usually results in a voiding pattern consistent with NDO and sphincter dyssynergia. Injury to either the sacral cord or cauda equina results in detrusor hypoactivity/areflexia with sphincter weakness.
Recent evidence has demonstrated that exosomes derived from mesenchymal stem cells (MSCs) may serve as a reservoir of miRNAs conferring protection from certain diseases. Hence, the current study was ...performed with the aim of investigating whether MSCs-exosomal miR-544 could exert protection against spinal cord injury (SCI). In the present study, bone mesenchymal stem cells (BMSCs) isolated from rat bone marrows were transfected with miR-544 mimic. The miR-544-overexpressing BMSCs-derived exosomes (BMSC-Exo) were intravenously injected into SCI model rats. Neurological function, histopathological changes, and the release of inflammatory cytokines were further examined. Results showed that BMSCs-exosomal miR-544 mitigated neural functional recovery after SCI. Moreover, overexpression of miR-544 in BMSC-Exo abated histologic deficits and neuronal loss caused by SCI. Notably, this therapeutic intervention also reduced inflammation following SCI. In conclusion, exosomes derived from miR-544-overexpressing BMSCs improved functional recovery and promoted neuronal survival by attenuating inflammation after SCI.
The role of autophagy in the recovery of spinal cord injury remains controversial; in particular, the mechanism of autophagy regulated degradation of ubiquitinated proteins has not been discussed to ...date. In this study, we investigated the protective role of basic fibroblast growth factor (bFGF) both in vivo and in vitro and demonstrated that excessive autophagy and ubiquitinated protein accumulation is involved in the rat model of trauma. bFGF administration improved recovery and increased the survival of neurons in spinal cord lesions in the rat model. The protective effect of bFGF is related to the inhibition of autophagic protein LC3II levels; bFGF treatment also enhances clearance of ubiquitinated proteins by p62, which also increases the survival of neuronal PC-12 cells. The activation of the downstream signals of the PI3K/Akt/mTOR pathway by bFGF treatment was detected both in vivo and in vitro. Combination therapy including the autophagy activator rapamycin partially abolished the protective effect of bFGF. The present study illustrates that the role of bFGF in SCI recovery is related to the inhibition of excessive autophagy and enhancement of ubiquitinated protein clearance via the activation of PI3K/Akt/mTOR signaling. Overall, our study suggests a new trend for bFGF drug development for central nervous system injuries and sheds light on protein signaling involved in bFGF action.
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