Absence of endogenous interleukin-10 enhances secondary inflammatory process after spinal cord compression injury in mice

Conditional deletion of IκBζ in hematopoietic cells promotes functional recovery after spinal cord injury in mice

BACKGROUND

Transcription factor protein IκBζ (encoded by the Nfkbiz gene) regulates nuclear factor-κB (NF-κB) and is involved in the pathophysiology of various inflammatory diseases. However, the role of IκBζ in secondary damage following spinal cord injury (SCI) remains to be determined. Here, we investigated the effect of IκBζ expressed in hematopoietic cells on the progression of secondary damage and functional recovery after SCI.

METHODS

We used conditional IκBζ-knockout mice (Mx1-Cre;Nfkbizfl/f) to examine the role of IκBζ in hematopoietic cells after SCI. Contusion SCI was induced using a force of 60 kdyn. The recovery of locomotor performance was evaluated using the nine-point Basso Mouse Scale (BMS) until 42 days post-injury. Expression patterns of inflammatory cytokines and chemokines were examined by quantitative real-time PCR or proteome array analysis. Bone marrow transplantation (BMT) was performed to eliminate the effect of IκBζ deletion in non-hematopoietic cells.

RESULTS

Mx1-Cre;Nfkbizfl/fl mice had significantly improved locomotor function compared with wild-type (WT) mice. The mRNA expression of Nfkbiz in WT mice peaked at 12 h after SCI and then decreased slowly in both the spinal cord and white blood cells. In situ hybridization showed that Nfkbiz mRNA was localized in cell nuclei, including macrophage-like cells, in the injured spinal cord of WT mice at 1 day after SCI. Compared with WT mice, Mx1-Cre;Nfkbizfl/fl mice had significantly increased mRNA expressions of interleukin (Il)-4 and Il-10 in the injured spinal cord. In addition, Mx1-Cre;Nfkbizfl/fl mice had significantly higher protein levels of granulocyte-macrophage colony-stimulating factor and C-C motif chemokine 11 compared with WT mice. BMT from Mx1-Cre;Nfkbizfl/fl mice into WT mice improved functional recovery after SCI compared with control mice (WT cells into WT mice).

CONCLUSIONS

IκBζ deletion in hematopoietic cells improved functional recovery after SCI, possibly by shifting the inflammatory balance towards anti-inflammatory and pro-regenerative directions.

Causal Association Between Inflammatory Proteins, Inflammatory Cells, and Cauda Equina Syndrome: A Two-Sample Mendelian Randomization

BACKGROUND

Recent studies have shown that inflammation plays a crucial role in the progression of cauda equina syndrome (CES). However, the exact cause-and-effect relationship between them is still unclear.

METHODS

We used CES data from the FinnGen genome-wide association study (GWAS), containing 329 cases and 408,351 control patients. Inflammatory proteins data were obtained from a large scale GWAS of 14,828 European ancestry participants, and inflammatory cells data were obtained from a GWAS summary of 3757 Sardinians. We chose inverse variance weighted as the main method and the Cochrane Q test to assess heterogeneity in the results. The MR-Egger intercept test and MR pleiotropy residual sum and outliers test were used to evaluate the horizontal pleiotropy, and sensitivity analysis was performed by leave-one-out analysis.

RESULTS

We examined robust associations between inflammatory proteins, inflammatory cells, and CES using Mendelian randomization. Two inflammatory proteins and 12 inflammatory cells were found as risk factors for CES: IL-8 and PD-L1; and basophil plasmacytoid dendritic cell, CD86+plasmacytoid dendritic cell, CD62L-plasmacytoid dendritic cell, CD39+secreting Treg, IgD+CD38-B cell, switched memory B cell, IgD+CD24+B cell, CD62L+dendritic cell, CD4+T cell, γδ T cell, and CD33dim HLA DR-myeloid cell. Two inflammatory proteins and 7 inflammatory cells were found as protective factors for CES: IL-10RA and CCL25; and transitional B cell, terminal differentiation double negative T cell, CD28-CD127-CD25++CD8br T cell, IgD+CD38br B cell, CD28+CD45RA-CD8br Treg, IgD+CD38-naive B cell, and granulocyte. Heterogeneity and pleiotropy analysis confirmed the reliability of the results. Our study reveals the causal relationship between inflammatory proteins, inflammatory cells, and CES, offering new insights for the development of future therapeutic drugs and early warning indicators.

CONCLUSIONS

Our findings extend genetic research to causal analysis between inflammatory proteins, cells, and CES. We found 2 proteins and 12 cells as risk factors and 2 proteins and 7 cells as protective factors. Further investigations are needed to verify whether these inflammation markers can be used to prevent or treat CES.

The Role of Interleukin-10 in the Pathogenesis and Treatment of a Spinal Cord Injury

Spinal cord injury (SCI) is a devastating condition that often leads to severe and permanent neurological deficits. The complex pathophysiology of an SCI involves a cascade of events, including inflammation, oxidative stress, and secondary injury processes. Among the myriad of molecular players involved, interleukin-10 (IL-10) emerges as a key regulator with the potential to modulate both the inflammatory response and promote neuroprotection. This comprehensive review delves into the intricate interplay of IL-10 in the pathogenesis of an SCI and explores its therapeutic implications in the quest for effective treatments. IL-10 has been found to regulate inflammation, oxidative stress, neuronal apoptosis, and glial scars after an SCI. Its neuroprotective properties have been evaluated in a plethora of animal studies. IL-10 administration, either isolated or in combination with other molecules or biomaterials, has shown neuroprotective effects through a reduction in inflammation, the promotion of tissue repair and regeneration, the modulation of glial scar formation, and improved functional outcomes. In conclusion, IL-10 emerges as a pivotal player in the pathogenesis and treatment of SCIs. Its multifaceted role in modulating inflammation, oxidative stress, neuronal apoptosis, glial scars, and neuroprotection positions IL-10 as a promising therapeutic target. The ongoing research exploring various strategies for harnessing the potential of IL-10 offers hope for the development of effective treatments that could significantly improve outcomes for individuals suffering from spinal cord injuries. As our understanding of IL-10's intricacies deepens, it opens new avenues for innovative and targeted therapeutic interventions, bringing us closer to the goal of alleviating the profound impact of SCIs on patients' lives.

Neuroprotective effects of interleukin 10 in spinal cord injury

Spinal cord injury (SCI) starts with a mechanical and/or bio-chemical insult, followed by a secondary phase, leading progressively to severe collapse of the nerve tissue. Compared to the peripheral nervous system, injured spinal cord is characterized by weak axonal regeneration, which leaves most patients impaired or paralyzed throughout lifetime. Therefore, confining, alleviating, or reducing the expansion of secondary injuries and promoting functional connections between rostral and caudal regions of lesion are the main goals of SCI therapy. Interleukin 10 (IL-10), as a pivotal anti-inflammatory and immunomodulatory cytokine, exerts a wide spectrum of positive effects in the treatment of SCI. The mechanisms underlying therapeutic effects mainly include anti-oxidative stress, limiting excessive inflammation, anti-apoptosis, antinociceptive effects, etc. Furthermore, IL-10 displays synergistic effects when combined with cell transplantation or neurotrophic factor, enhancing treatment outcomes. This review lists pleiotropic mechanisms underlying IL-10-mediated neuroprotection after SCI, which may offer fresh perspectives for clinical translation.

Modulating neuroinflammation through molecular, cellular and biomaterial-based approaches to treat spinal cord injury

The neuroinflammatory response that is elicited after spinal cord injury contributes to both tissue damage and reparative processes. The complex and dynamic cellular and molecular changes within the spinal cord microenvironment result in a functional imbalance of immune cells and their modulatory factors. To facilitate wound healing and repair, it is necessary to manipulate the immunological pathways during neuroinflammation to achieve successful therapeutic interventions. In this review, recent advancements and fresh perspectives on the consequences of neuroinflammation after SCI and modulation of the inflammatory responses through the use of molecular-, cellular-, and biomaterial-based therapies to promote tissue regeneration and functional recovery will be discussed.

Neuroprotective effects of lovastatin against traumatic spinal cord injury in rats

BACKGROUND

Lovastatin, as a drug of statins subgroup, has been conceptualized to have anti-inflammatory, antioxidant, and anti-apoptotic properties. Accordingly, the present study aimed to investigate the neuroprotective ramification of lovastatin on spinal cord injury (SCI).

MATERIAL AND METHODS

Seventy-five female adult Wistar rats were divided into five groups (n = 15). In addition to non-treated (Control group) and laminectomy alone (Sham group), SCI animals were randomly assigned to non-treated spinal cord injury (SCI group), treated with 2 mg/kg of lovastatin (Lova 2 group), and treated with 5 mg/kg of lovastatin (Lova 5 group). At the end of the study, to evaluate the treatments, MDA, CAT, SOD, and GSH factors were evaluated biochemically, apoptosis and gliosis were assessed by immunohistochemical while measuring caspase-3 and GFAP antibodies, and inflammation was estimated by examining the expression of IL-10, TNF-α, and IL-1β genes. The stereological method was used to appraise the total volume of the spinal cord at the site of injury, the volume of the central cavity created, and the density of neurons and glial cells in the traumatic area. In addition, Basso-Beattie-Bresnehan (BBB) and narrow beam test (NBT) were utilized to rate neurological functions.

RESULTS

Our results exposed the fact that biochemical factors (except MDA), stereological parameters, and neurological functions were significantly ameliorated in both lovastatin-treated groups, especially in Lova 5 ones, compared to the SCI group. The expression of the IL-10 gene was significantly upregulated in both lovastatin-treated groups compared to the SCI group and was considerably heighten in Lova 5 group. Expression of TNF-α and IL-1β, as well as the rate of apoptosis and GFAP positive cells significantly decreased in both lovastatin treated groups compared to the SCI group, and it was more pronounced in the Lova 5 ones.

CONCLUSION

Overall, using lovastatin, especially at a dose of 5 mg/kg, has a dramatic neuroprotective impact on SCI treatment.

The Glial Cells Respond to Spinal Cord Injury

It is been over 100 years since glial cells were discovered by Virchow. Since then, a great deal of research was carried out to specify these further roles and properties of glial cells in central nervous system (CNS). As it is well-known that glial cells, such as astrocytes, microglia, oligodendrocytes (OLs), and oligodendrocyte progenitor cells (OPCs) play an important role in supporting and enabling the effective nervous system function in CNS. After spinal cord injury (SCI), these glial cells play different roles in SCI and repair. In this review, we will discuss in detail about the role of glial cells in the healthy CNS and how they respond to SCI.

Inflammation after spinal cord injury: a review of the critical timeline of signaling cues and cellular infiltration

Traumatic spinal cord injury (SCI) is a devastating neurological condition that results in a loss of motor and sensory function. Although extensive research to develop treatments for SCI has been performed, to date, none of these treatments have produced a meaningful amount of functional recovery after injury. The primary injury is caused by the initial trauma to the spinal cord and results in ischemia, oxidative damage, edema, and glutamate excitotoxicity. This process initiates a secondary injury cascade, which starts just a few hours post-injury and may continue for more than 6 months, leading to additional cell death and spinal cord damage. Inflammation after SCI is complex and driven by a diverse set of cells and signaling molecules. In this review, we utilize an extensive literature survey to develop the timeline of local immune cell and cytokine behavior after SCI in rodent models. We discuss the precise functional roles of several key cytokines and their effects on a variety of cell types involved in the secondary injury cascade. Furthermore, variations in the inflammatory response between rats and mice are highlighted. Since current SCI treatment options do not successfully initiate functional recovery or axonal regeneration, identifying the specific mechanisms attributed to secondary injury is critical. With a more thorough understanding of the complex SCI pathophysiology, effective therapeutic targets with realistic timelines for intervention may be established to successfully attenuate secondary damage.

Inhibition of miR-145-5p Reduces Spinal Cord Injury-Induced Inflammatory and Oxidative Stress Responses via Affecting Nurr1-TNF-α Signaling Axis

Inflammation and oxidative stress feature prominently in the secondary spinal cord injury (SCI). The present work is targeted at deciphering miR-145-5p's role and underlying mechanism in SCI. We randomly divided Sprague-Dawley rats into SCI group and control group. Microglial BV2 cells were separated into control group and lipopolysaccharide (LPS) treatment group. Enzyme-linked immunosorbent assay was carried out for determining the concentrations of interleukin-6, interleukin-1β, and tumor necrosis factor-α (TNF-α). The expressions of malondialdehyde, glutathione peroxidase, superoxide dismutase, and reactive oxygen species were also detected. TNF-α, miR-145-5p, and Nurr1 expressions were examined by western blot and quantitative real-time polymerase chain reaction. Western blotting and dual-luciferase reporter gene assay were conducted to examine the regulating impact that miR-145-5p had on Nurr1 and TNF-α. MiR-145-5p was remarkably upregulated in the SCI rat model's spinal cord tissues and BV2 cells treated with LPS, and Nurr1 expression was dramatically lowered. Furthermore, miR-145-5p inhibition markedly repressed inflammatory and oxidative stress responses. Moreover, it was proved that Nurr1 was a direct miR-145-5p target. The inhibition of miR-145-5p helped promote Nurr1 expression to block TNF-α signaling. MiR-145-5p inhibition mitigates inflammation and oxidative stress via targeting Nurr1 to regulate TNF-α signaling, which ameliorates SCI.

Synergistic neuroprotective effects of hyperbaric oxygen and N-acetylcysteine against traumatic spinal cord injury in rat

BACKGROUND

The mitochondrial dysfunction and following oxidative stress, as well as the spread of inflammation plays major roles in the failure to regenerate following severe spinal cord injury (SCI). In this regard, we investigated the neuroprotective effects of hyperbaric oxygen (HBO), as an anti-apoptotic and anti-inflammatory agent, and N-acetylcysteine (NAC), as a mitochondrial enhancer, in SCI.

MATERIAL AND METHODS

Seventy-five female adult Wistar rats divided into five groups (n = 15): laminectomy alone (Sham) group, SCI group, HBO group (underwent SCI and received HBO), NAC group (underwent SCI and received NAC), and HBO+NAC group (underwent SCI and simultaneously received NAC and HBO). At the end of study, spinal cord tissue samples were taken for evaluation of biochemical profiles including malondialdehyde (MDA), catalase (CAT), superoxide dismutase (SOD) and glutathione (GSH) levels, immunohistochemistry for caspase-3 as well as gene expressions of interleukin (IL)-10, tumor necrosis factor alpha (TNF-α), and IL-1β. Stereological assessments were performed to determine the total volumes, central cavity volumes and as well as numerical density of the neural and glial cells in traumatic area. Moreover, neurological functions were evaluated by the Basso-Beattie-Bresnehan (BBB) and electromyography (EMG).

RESULTS

Our results showed that the stereological parameters, biochemical profiles (except MDA) and neurological function were significantly higher in each HBO, NAC and HBO+NAC groups compared to the SCI group, and were highest in HBO+NAC ones. The transcript for IL-10 gene was significantly upregulated in all treatment regimens compared to SCI group, and was highest in HBO+NAC ones. While expression of TNF-α and IL-1β, latency, as well as density of apoptosis cells in caspase-3 evaluation significantly more decreased in HBO+NAC group compared to other groups.

CONCLUSION

Overall, using combined therapy with HBO and NAC has synergistic neuroprotective effects in SCI treatment.

Lentiviral Interleukin-10 Gene Therapy Preserves Fine Motor Circuitry and Function After a Cervical Spinal Cord Injury in Male and Female Mice

In mammals, spinal cord injuries often result in muscle paralysis through the apoptosis of lower motor neurons and denervation of neuromuscular junctions. Previous research shows that the inflammatory response to a spinal cord injury can cause additional tissue damage after the initial trauma. To modulate this inflammatory response, we delivered lentiviral anti-inflammatory interleukin-10, via loading onto an implantable biomaterial scaffold, into a left-sided hemisection at the C5 vertebra in mice. We hypothesized that improved behavioral outcomes associated with anti-inflammatory treatment are due to the sparing of fine motor circuit components. We examined behavioral recovery using a ladder beam, tissue sparing using histology, and electromyogram recordings using intraspinal optogenetic stimulation at 2 weeks post-injury. Ladder beam analysis shows interleukin-10 treatment results in significant improvement of behavioral recovery at 2 and 12 weeks post-injury when compared to mice treated with a control virus. Histology shows interleukin-10 results in greater numbers of lower motor neurons, axons, and muscle innervation at 2 weeks post-injury. Furthermore, electromyogram recordings suggest that interleukin-10-treated animals have signal-to-noise ratios and peak-to-peak amplitudes more similar to that of uninjured controls than to that of control injured animals at 2 weeks post-injury. These data show that gene therapy using anti-inflammatory interleukin-10 can significantly reduce tissue damage and subsequent motor deficits after a spinal cord injury. Together, these results suggest that early modulation of the injury response can preserve muscle function with long-lasting benefits.

Dilated cardiomyopathy impairs mitochondrial biogenesis and promotes inflammation in an age- and sex-dependent manner

Dilated cardiomyopathy (DCM) belongs to the myocardial diseases associated with a severe impairment of cardiac function, but the question of how sex and age affect this pathology has not been fully explored. Impaired energy homeostasis, mitochondrial dysfunction, and systemic inflammation are well-described phenomena associated with aging. In this study, we investigated if DCM affects these phenomena in a sex- and age-related manner. We analyzed the expression of mitochondrial and antioxidant proteins and the inflammatory state in DCM heart tissue from younger and older women and men. A significant downregulation of Sirt1 expression was detected in older DCM patients. Sex-related differences were observed in the phosphorylation of AMPK that only appeared in older males with DCM, possibly due to an alternative Sirt1 regulation mechanism. Furthermore, reduced expression of several mitochondrial proteins (TOM40, TIM23, Sirt3, and SOD2) and genes (cox1, nd4) was only detected in old DCM patients, suggesting that age has a greater effect than DCM on these alterations. Finally, an increased expression of inflammatory markers in older, failing hearts, with a stronger pro-inflammatory response in men, was observed. Together, these findings indicate that age- and sex-related increased inflammation and disturbance of mitochondrial homeostasis occurs in male individuals with DCM.

Advances in immunotherapy for the treatment of spinal cord injury

Spinal cord injury (SCI) is a leading cause of morbidity and disability in the world. Over the past few decades, the exact molecular mechanisms describing secondary, persistent injuries, as well as primary and transient injuries, have attracted massive attention to the clinicians and researchers. Recent investigations have distinctly shown the critical roles of innate and adaptive immune responses in regulating sterile neuroinflammation and functional outcomes after SCI. In past years, some promising advances in immunotherapeutic options have efficaciously been identified for the treatment of SCI. In our narrative review, we have mainly focused on the new therapeutic strategies such as the maturation and apoptosis of immune cells by several agents, mesenchymal stem cells (MSCs) as well as multi-factor combination therapy, which have recently provided novel ideas and prospects for the future treatment of SCI. This article also illustrates the latest progress in clarifying the potential roles of innate and adaptive immune responses in SCI, the progression and specification of prospective immunotherapy and outstanding issues in the area.

Current Insights Into the Pathology of Canine Intervertebral Disc Extrusion-Induced Spinal Cord Injury

Spinal cord injury (SCI) in dogs is commonly attributed to intervertebral disc extrusion (IVDE). Over the last years substantial progress was made in the elucidation of factors contributing to the pathogenesis of this common canine disease. A detailed understanding of the underlying histopathological and molecular alterations in the lesioned spinal cord represents a prerequisite to translate knowledge on the time course of secondary injury processes into the clinical setting. This review summarizes the current state of knowledge of the underlying pathology of canine IVDE-related SCI. Pathological alterations in the spinal cord of dogs affected by IVDE-related SCI include early and persisting axonal damage and glial responses, dominated by phagocytic microglia/macrophages. These processes are paralleled by a pro-inflammatory microenvironment with dysregulation of cytokines and matrix metalloproteinases within the spinal cord. These data mirror findings from a clinical and therapeutic perspective and can be used to identify biomarkers that are able to more precisely predict the clinical outcome. The pathogenesis of progressive myelomalacia, a devastating complication of SCI in dogs, is not understood in detail so far; however, a fulminant and exaggerating secondary injury response with massive reactive oxygen species formation seems to be involved in this unique neuropathological entity. There are substantial gaps in the knowledge of pathological changes in IVDE with respect to more advanced and chronic lesions and the potential involvement of demyelination. Moreover, the role of microglia/macrophage polarization in IVDE-related SCI still remains to be investigated. A close collaboration of clinical neurologists and veterinary pathologists will help to facilitate an integrative approach to a more detailed understanding of the molecular pathogenesis of canine IVDE and thus to identify therapeutic targets.

Aging-Related Phenotypic Conversion of Medullary Microglia Enhances Intraoral Incisional Pain Sensitivity

Activated microglia involved in the development of orofacial pain hypersensitivity have two major polarization states. The aim of this study was to assess the involvement of the aging-related phenotypic conversion of medullary microglia in the enhancement of intraoral pain sensitivity using senescence-accelerated mice (SAM)-prone/8 (SAMP8) and SAM-resistant/1 (SAMR1) mice. Mechanical head-withdrawal threshold (MHWT) was measured for 21 days post palatal mucosal incision. The number of CD11c-immunoreactive (IR) cells [affective microglia (M1)] and CD163-IR cells [protective microglia (M2)], and tumor-necrosis-factor-α (TNF-α)-IR M1 and interleukin (IL)-10-IR M2 were analyzed via immunohistochemistry on days 3 and 11 following incision. The decrease in MHWT observed following incision was enhanced in SAMP8 mice. M1 levels and the number of TNF-α-IR M1 were increased on day 3 in SAMP8 mice compared with those in SAMR1 mice. On day 11, M1 and M2 activation was observed in both groups, whereas IL-10-IR M2 levels were attenuated in SAMP8 mice, and the number of TNF-α-IR M1 cells increased, compared to those in SAMR1 mice. These results suggest that the mechanical allodynia observed following intraoral injury is potentiated and sustained in SAMP8 mice due to enhancement of TNF-α signaling, M1 activation, and an attenuation of M2 activation accompanying IL-10 release.

Efficacy of autologous bone marrow mononuclear cell transplantation in dogs with chronic spinal cord injury

Background:

Spinal cord injury (SCI) is relatively common in dogs and is a devastating condition involving loss of sensory neurons and motor neurons. However, the main clinical protocol for the management of SCI is surgery to decompress and stabilize the vertebra. Cell transplantation therapy is a very promising strategy for the treatment of chronic SCI, but extensive preclinical and clinical research work remains.

Aim:

The aim of this study is to confirm the effect of bone marrow-derived mononuclear cell (BM-MNC) transplantation for chronic SCI in dogs.

Methods:

We tested the treatment efficiency of chronic SCI in 12 dogs using BM-MNC transplantation. Neurological evaluation used the Texas Spinal Cord Injury Scale (TSCIS). Concurrently, we characterized the transplanted cells by evaluation using quantitative real-time polymerase chain reaction, flow cytometry, and enzyme-linked immunosorbent assay.

Result:

All dogs had a pre-transplantation TSCIS score of 0. Two animals did not show any improvement in their final TSCIS scores. The remaining 10 dogs (83.4%) achieved improvement in the final TSCIS scores. Five of them (41.7%) regained ambulatory function with a TSCIS score greater than 10. We determined that canine BM-MNCs expressed hepatocyte growth factor (HGF) mRNA at higher levels than other cytokines, with significant increases in HGF levels in cerebrospinal fluid within 48 hours after autologous BM-MNC transplantation into the subarachnoid space of the spinal dura matter in dogs.

Conclusions:

BM-MNC transplantation may be effective for at least some cases of chronic SCI.

Up-regulation of MicroRNAs-21 and -223 in a Sprague-Dawley Rat Model of Traumatic Spinal Cord Injury

In this experimental animal study, we examined alterations in the degree of transcription of two microRNAs (miRs)—miR-21 and -223—in a Sprague-Dawley (SD) rat model of traumatic spinal cord injury (TSCI). Depending on the volume of the balloon catheter (V), a total of 75 male SD rats were divided into the three experimental groups: the sham group (n = 25; V = 0 μL), the mild group (n = 25; V = 20 μL), and the severe group (n = 25; V = 50 μL). Successful induction of TSCI was confirmed on both locomotor rating scale at 4 h and 1, 3 and 7 days post-lesion and histopathologic examinations. Then, RNA isolation and quantitative polymerase chain reaction (PCR) were performed. No differences in the level of miR-21 expression were found at the first time point studied (4 h post-lesion) between the three experimental groups, whereas such differences were significant at all the other time points (p < 0.05). Moreover, there were significant alterations in the level of miR-223 expression at all time points studied through all the experimental groups (p < 0.05). Furthermore, locomotor rating scale scores had a linear relationship with the level of miR-21 expression (R² = 0.4363, Y = 1.661X + 3.096) and that of miR-223 one (R² = 0.9104, Y = 0.8385X + 2.328). Taken together, we conclude that up-regulation of miR-21 and -223 might be closely associated with progression and the early course of TSCI, respectively.

Dihydrotanshinone I Alleviates Spinal Cord Injury via Suppressing Inflammatory Response, Oxidative Stress and Apoptosis in Rats

Background

Spinal cord injury (SCI) is a serious nervous system injury, causing extremely low quality of life and immensurable economic losses. However, there is few therapies that can effectively cure the injury. The goal of the present study was to explore the potential therapeutic effects of dihydrotanshinone I (DI) for SCI and the involving mechanism.

Material/Methods

A SCI rat model was structured to investigate the effects of DI on recovery of SCI. Tarlov’s scale was employed to assess the neuronal function and histopathological examination was carried out by hematoxylin and eosin staining. In addition, tumor necrosis factor (TNF)-α, interleukin (IL)-6, IL-1β, inducible nitric oxide synthase (iNOS), total oxidant status (TOS) and total antioxidant status (TAS) levels were detected. Tunel assay and western blot analysis were performed to evaluate cell apoptosis. Furthermore, western blot assay was used to measure the protein expressions.

Results

The results demonstrated that the treatment of DI alleviated the pathological damage induced by SCI and promoted the neuronal functional recovery. DI suppressed TNF-α, IL-1β, IL-6, iNOS, and TOS levels while improved the TAS level. Moreover, increased cell apoptosis in SCI rats was inhibited by administration of DI. Most importantly, DI reserved the soaring of TLR4, MyD88, HMGB1, and NOX4 level after induction of SCI. Thus, the observation revealed that the HMGB1/TLR4/NOX4 pathway may be involved in the protective effects of DI on SCI.

Conclusions

In conclusion, the findings suggest that DI alleviates SCI by restraining secretion of inflammatory factors, and occurrence of oxidative stress and apoptosis in vivo. DI may be developed into an effective alternative therapy for SCI in clinic.

Curcumin Alleviates Lipopolysaccharide (LPS)-Activated Neuroinflammation via Modulation of miR-199b-5p/IκB Kinase β (IKKβ)/Nuclear Factor Kappa B (NF-κB) Pathway in Microglia

BACKGROUND Microglia reside in the spinal cord plays a key role in the onset, progression of post-spinal cord injury (SCI) neuroinflammation. Curcumin has been shown to exhibit diverse anti-inflammatory and anti-tumor activities. The aim of this study was to explore the effect of curcumin on the inflammatory response in lipopolysaccharide (LPS)-activated microglia and its mechanism. MATERIAL AND METHODS The expression levels of phosphorylated-p65 (p-p65), tumor necrosis factor (TNF)-alpha, interleukin (IL)-1ß, and IkappaB kinase ß (IKKß) were examined by western blot assay. MiR-199b-5p expression was detected by quantitative real-time polymerase chain reaction assay. The putative binding sites of miR-199b-5p in IKKß 3'UTR were predicted by bioinformatics, and direct interaction between miR-199b-5p and IKKß was verified by dual-luciferase reporter assay and RNA-immunoprecipitation assay. RESULTS Curcumin significantly suppressed inflammatory response induced by LPS by inactivation of nuclear factor kappa B (NF-kappaB) in microglial cells, as reflected by the decreased levels of p-p65, as well as the pro-inflammatory mediators, including inducible nitric oxide synthase (iNOS), TNF-alpha, and IL-1ß. Moreover, curcumin increased the level of miR-199b-5p and decreased IKKß expression in activated microglial cells. Knockdown of miR-199b-5p or overexpression of IKKß reversed the inhibitory effect of curcumin on inflammatory response and NF-kappaB activation. MiR-199b-5p directly targeted IKKß and suppressed its expression. Silencing of IKKß abolished miR-199b-5p-stimulated inflammatory cytokines production and NF-kappaB activation. CONCLUSIONS Curcumin attenuated neuroinflammation induced by LPS through regulating miR-199b-5p/IKKß/NF-kappaB axis in microglia.

Involvement of Interleukin-10 in Analgesia of Electroacupuncture on Incision Pain

Objective

Postincision pain often occurs after surgery and is an emergency to be treated in clinic. Electroacupuncture (EA) is a Chinese traditional treatment widely used to cure acute or chronic pain, but its mechanism is not clear. Interleukin-10 (IL-10) is a powerful anti-inflammatory cytokine that shows neuroprotective effects in inflammation and injury in the CNS. The present study attempts to reveal that IL-10 is crucial for EA analgesia on postincision pain.

Methods

A model of incision pain was established in C57BL/6J mice. The pain threshold was detected by behavioral test, and the expression of IL-10 and its receptor was detected by an immunohistochemical method. C-fiber-evoked field potentials were recorded by in vivo analysis.

Results

The mechanical allodynia induced by paw incision was significantly inhibited by pretreatment of EA in mice. Intrathecal injection of IL-10 neutralizing antibody (2 µg/10 µL) but not intraplantar injection (10 µg/10 µL) reversed the analgesia of EA. The upregulations of IL-10 mRNA and protein were induced by EA at 6 h and 1 d after incision, respectively. Spinal long-term potentiation (LTP), a substrate for central sensitization, was also suppressed by EA with IL-10. IL-10 recombinant protein (1 µg/10 µL, i.t.) mimicked the analgesia of EA on mechanical allodynia and inhibition on the spinal LTP. Posttreatment of EA after incision also transitorily relieved the mechanical allodynia, which can be blocked by spinal IL-10 antibody. IL-10 and its receptor, IL-10RA, are predominantly expressed in the superficial spinal astrocytes.

Conclusions

These results suggested that pretreatment of EA effectively prevented postincision pain and IL-10 in spinal astrocytes was critical for the analgesia of EA and central sensitization.

The effects of human immunoglobulin G on enhancing tissue protection and neurobehavioral recovery after traumatic cervical spinal cord injury are mediated through the neurovascular unit

Background

Spinal cord injury (SCI) is a condition with few effective treatment options. The blood-spinal cord barrier consists of pericytes, astrocytes, and endothelial cells, which are collectively termed the neurovascular unit. These cells support spinal cord homeostasis by expressing tight junction proteins. Physical trauma to the spinal cord disrupts the barrier, which leads to neuroinflammation by facilitating immune cell migration to the damaged site in a process involving immune cell adhesion. Immunosuppressive strategies, including methylprednisolone (MPSS), have been investigated to treat SCI. However, despite some success, MPSS has the potential to increase a patient’s susceptibility to wound infection and impaired wound healing. Hence, immunomodulation may be a more attractive approach than immunosuppression. Approved for modulating neuroinflammation in certain disorders, including Guillain-Barre syndrome, intravenous administration of human immunoglobulin G (hIgG) has shown promise in the setting of experimental SCI, though the optimal dose and mechanism of action remain undetermined.

Methods

Female adult Wistar rats were subjected to moderate-severe clip compression injury (35 g) at the C7-T1 level and randomized to receive a single intravenous (IV) bolus of hIgG (0.02, 0.2, 0.4, 1, 2 g/kg), MPSS (0.03 g/kg), or control buffer at 15 min post-SCI. At 24 h and 6 weeks post-SCI, molecular, histological, and neurobehavioral effects of hIgG were analyzed.

Results

At 24 h post-injury, human immunoglobulin G co-localized with spinal cord pericytes, astrocytes, and vessels. hIgG (2 g/kg) protected the spinal cord neurovasculature after SCI by increasing tight junction protein expression and reducing inflammatory enzyme expression. Improvements in vascular integrity were associated with changes in spinal cord inflammation. Interestingly, hIgG (2 g/kg) increased serum expression of inflammatory cytokines and co-localized (without decreasing protein expression) with spinal cord vascular cell adhesion molecule-1, a protein used by immune cells to enter into inflamed tissue. Acute molecular benefits of hIgG (2 g/kg) led to greater tissue preservation, functional blood flow, and neurobehavioral recovery at 6 weeks post-SCI. Importantly, the effects of hIgG (2 g/kg) were superior to control buffer and hIgG (0.4 g/kg), and comparable with MPSS (0.03 g/kg).

Conclusions

hIgG (2 g/kg) is a promising therapeutic approach to mitigate secondary pathology in SCI through antagonizing immune cell infiltration at the level of the neurovascular unit.

Glia in amyotrophic lateral sclerosis and spinal cord injury: common therapeutic targets

The toolkit for repairing damaged neurons in amyotrophic lateral sclerosis (ALS) and spinal cord injury (SCI) is extremely limited. Here, we reviewed the in vitro and in vivo studies and clinical trials on nonneuronal cells in the neurodegenerative processes common to both these conditions. Special focus was directed to microglia and astrocytes, because their activation and proliferation, also known as neuroinflammation, is a key driver of neurodegeneration. Neuroinflammation is a multifaceted process that evolves during the disease course, and can be either beneficial or toxic to neurons. Given the fundamental regulatory functions of glia, pathogenic mechanisms in neuroinflammation represent promising therapeutic targets. We also discussed neuroprotective, immunosuppressive, and stem-cell based approaches applicable to both ALS and SCI.

Human gingival mesenchymal stem cells pretreated with vesicular moringin nanostructures as a new therapeutic approach in a mouse model of spinal cord injury

Spinal cord injury (SCI) is a neurological disorder that arises from a primary acute mechanical lesion, followed by a pathophysiological cascade of events that leads to further spinal cord tissue damage. Several preclinical and clinical studies have highlighted the ability of stem cell therapy to improve long-term functional recovery in SCI. Previously, we demonstrated that moringin (MOR) treatment accelerates the differentiation process in mesenchymal stem cells inducing an early up-regulation of neural development associated genes. In the present study, we investigated the anti-inflammatory, anti-apoptotic, and regenerative effects of gingival mesenchymal stem cells (GMSCs) pretreated with nanostructured liposomes enriched with MOR in an animal model of SCI. SCI was produced by extradural compression of the spinal cord at levels T6-T7 in ICR (CD-1) mice. Animals were randomly assigned to the following groups: Sham, SCI, SCI + GMSCs (1 × 106  cell/i.v.), SCI + MOR-GMSCs (1 × 106  cell/i.v.). Our data show that MOR-treated GMSCs exert anti-inflammatory and anti-apoptotic activities. In particular, MOR-treated GMSCs are able to reduce the spinal cord levels of COX-2, GFAP, and inflammatory cytokines IL-1β and IL-6 and to restore spinal cord normal morphology. Also, MOR-treated GMSCs influenced the apoptotic pathway, by reducing Bax, caspase 3, and caspase 9 expressions.

Sustained interleukin-10 delivery reduces inflammation and improves motor function after spinal cord injury

Background

The anti-inflammatory cytokine interleukin-10 (IL-10) has been explored previously as a treatment method for spinal cord injury (SCI) due to its ability to attenuate pro-inflammatory cytokines and reduce apoptosis. Primary limitations when using systemic injections of IL-10 are that it is rapidly cleared from the injury site and that it does not cross the blood–spinal cord barrier.

Objective

Here, mineral-coated microparticles (MCMs) were used to obtain a local sustained delivery of IL-10 directly into the injury site after SCI.

Methods

Female Sprague-Dawley rats were contused at T10 and treated with either an intraperitoneal injection of IL-10, an intramedullary injection of IL-10, or MCMs bound with IL-10 (MCMs+IL-10). After treatment, cytokine levels were measured in the spinal cord, functional testing and electrophysiology were performed, axon tracers were injected into the brainstem and motor cortex, macrophage levels were counted using flow cytometry and immunohistochemistry, and lesion size was measured.

Results

When treated with MCMs+IL-10, IL-10 was significantly elevated in the injury site and inflammatory cytokines were significantly suppressed, prompting significantly less cells expressing antigens characteristic of inflammatory macrophages and significantly more cells expressing antigens characteristic of earlier stage anti-inflammatory macrophages. Significantly more axons were preserved within the rubrospinal and reticulospinal tracts through the injury site when treated with MCMs+IL-10; however, there was no significant difference in corticospinal tract axons preserved, regardless of treatment group. The rats treated with MCMs+IL-10 were the only group with a significantly higher functional score compared to injured controls 28 days post-contusion.

Conclusion

These data demonstrate that MCMs can effectively deliver biologically active IL-10 for an extended period of time altering macrophage phenotype and aiding in functional recovery after SCI.

Glia in amyotrophic lateral sclerosis and spinal cord injury: common therapeutic targets

The toolkit for repairing damaged neurons in amyotrophic lateral sclerosis (ALS) and spinal cord injury (SCI) is extremely limited. Here, we reviewed the in vitro and in vivo studies and clinical trials on nonneuronal cells in the neurodegenerative processes common to both these conditions. Special focus was directed to microglia and astrocytes, because their activation and proliferation, also known as neuroinflammation, is a key driver of neurodegeneration. Neuroinflammation is a multifaceted process that evolves during the disease course, and can be either beneficial or toxic to neurons. Given the fundamental regulatory functions of glia, pathogenic mechanisms in neuroinflammation represent promising therapeutic targets. We also discussed neuroprotective, immunosuppressive, and stem-cell based approaches applicable to both ALS and SCI.

Endogenous Interleukin-10 Deficiency Exacerbates Vascular Pathology in Traumatic Cervical Spinal Cord Injury

Although the majority of traumatic spinal cord injuries (SCIs) take place at the cervical level, pre-clinical studies have been disproportionally focused on thoracic insults. With differences in anatomy, physiology, and immune response between spinal cord levels, there is evidence that injury pathophysiology may vary, requiring tailored treatment paradigms. Further, as only a few therapies have been successfully translated to the clinic, cervical models are increasingly recognized as essential for the characterization of trauma and therapy. Using a novel and clinically relevant cervical contusion-compression mouse model of bilateral incomplete injury, this study aimed to assess the role of interleukin10 (IL-10), a potent cytokine with broad anti-inflammatory effects, in SCI vascular pathology. While the effects of IL-10 loss have been previously evaluated, the vascular changes are poorly characterized. Here, using in vivo high-resolution ultrasound imaging, we demonstrate that IL-10 deficiency is associated with increased acute vascular damage. Importantly, the loss of endogenous IL-10 led to significant differences in the acute systemic response to SCI, specifically the circulating levels of IL-12 (p70), LIX (CXCL5), IL-1β, tumor necrosis factor (TNF)-α, and IL-6 relative to genotype sham controls. These effects also fostered modest impairments in long-term functional recovery, assessed by the Basso Mouse Scale, as well as histological outcomes.

Traumatic Spinal Cord Injury: An Overview of Pathophysiology, Models and Acute Injury Mechanisms

Traumatic spinal cord injury (SCI) is a life changing neurological condition with substantial socioeconomic implications for patients and their care-givers. Recent advances in medical management of SCI has significantly improved diagnosis, stabilization, survival rate and well-being of SCI patients. However, there has been small progress on treatment options for improving the neurological outcomes of SCI patients. This incremental success mainly reflects the complexity of SCI pathophysiology and the diverse biochemical and physiological changes that occur in the injured spinal cord. Therefore, in the past few decades, considerable efforts have been made by SCI researchers to elucidate the pathophysiology of SCI and unravel the underlying cellular and molecular mechanisms of tissue degeneration and repair in the injured spinal cord. To this end, a number of preclinical animal and injury models have been developed to more closely recapitulate the primary and secondary injury processes of SCI. In this review, we will provide a comprehensive overview of the recent advances in our understanding of the pathophysiology of SCI. We will also discuss the neurological outcomes of human SCI and the available experimental model systems that have been employed to identify SCI mechanisms and develop therapeutic strategies for this condition.

Protocatechuic acid improves functional recovery after spinal cord injury by attenuating blood-spinal cord barrier disruption and hemorrhage in rats

After spinal cord injury (SCI), blood-spinal cord barrier (BSCB) disruption and hemorrhage lead to blood cell infiltration and progressive secondary injuries including inflammation. Inflammatory response is one of the major events resulting in apoptosis, scar formation and neuronal dysfunction after SCI. Here, we investigated whether protocatechuic acid (PCA), a natural phenolic compound, would attenuate BSCB disruption and hemorrhage, leading to functional improvement after SCI. After a moderate contusion injury at T9, PCA (50 mg/kg) was administrated via intraperitoneal injection immediately, 6 h, and 12 h after SCI, and the same dose of PCA once a day until 7 d after injury. Our data show that PCA inhibited apoptotic cell death of neurons and oligodendrocytes and improved functional recovery after injury. PCA also attenuated BSCB disruption and hemorrhage and reduced the infiltration of neutrophils and macrophages compared to vehicle control. Moreover, PCA inhibited the expression and activation of matrix metalloprotease-9, which is well known to disrupt BSCB after SCI. Furthermore, PCA treatment significantly inhibited the expression of sulfonylurea receptor 1 and transient receptor potential melastatin 4, which are known to mediate hemorrhage at an early stage after SCI. Consistent with these findings, the mRNA and protein expression of inflammatory mediators such as tumor necrosis factor alpha, interleukin 1 beta, cyclooxygenase-2, inducible nitric oxide synthase, and chemokines was significantly alleviated by PCA treatment. Thus, our results suggest that PCA improved functional recovery after SCI in part by inhibiting BSCB disruption and hemorrhage through the down-regulation of sulfonylurea receptor 1/transient receptor potential melastatin 4 and matrix metalloprotease-9.

Regulation of Inflammatory Cytokines for Spinal Cord Injury Repair Through Local Delivery of Therapeutic Agents

The balance of inflammation is critical to the repair of spinal cord injury (SCI), which is one of the most devastating traumas in human beings. Inflammatory cytokines, the direct mediators of local inflammation, have differential influences on the repair of the injured spinal cord. Some inflammatory cytokines are demonstrated beneficial to spinal cord repair in SCI models, while some detrimental. Various animal researches have revealed that local delivery of therapeutic agents efficiently regulates inflammatory cytokines and promotes repair from SCI. Quite a few clinical studies have also shown the promotion of repair from SCI through regulation of inflammatory cytokines. However, local delivery of a single agent affects only a part of the inflammatory cytokines that need to be regulated. Meanwhile, different individuals have differential profiles of inflammatory cytokines. Therefore, future studies may aim to develop personalized strategies of locally delivered therapeutic agent cocktails for effective and precise regulation of inflammation, and substantial functional recovery from SCI.

Yellow Laser Stimulation at GV2 Acupoint Mitigates Apoptosis, Oxidative Stress, Inflammation, and Motor Deficit in Spinal Cord Injury Rats

Currently, the suppression of oxidative stress and inflammation is considered as the treatment targets of spinal cord injury due to their roles on the hindrance of recovery process. Since laser acupuncture decreased oxidative stress and enhanced the survival of neurons from oxidative stress damage and GV2 stimulation was selected as one stimulated acupoint in order to enhance the recovery of spinal cord injury, we hypothesized that laser acupuncture at GV2 should enhance the recovery of spinal cord injury. To test this hypothesis, male Wistar rats were induced spinal cord injury at T10 level and they were exposed to a 10 minute-stimulation at GV2 by yellow laser. Laser acupuncture was performed at 0.25 and 1, 2, 6, and 12 hours after spinal cord injury. Then, the stimulation was performed once daily for 7 days. Locomotor assessment was carried out on days 3 and 7 after injury. At the end of study period, the densities of polymorphonuclear of leukocyte, Bax, Caspase-3, Bcl-2, and BDNF positive stained cells in ventral horn of spinal cord were determined. Cyclooxygenase-2 (COX-2), interleukin-6 (IL-6), and oxidative stress status was also assessed. The results showed that laser acupuncture at GV2 increased BBB score, gross motor score, and densities of Bcl-2 and BDNF positive stained cells but decreased density with polymorphonuclear leukocyte, the densities of Bax and Caspase-3 positive stained cells, COX-2 level, and oxidative stress status in ventral horn of the lesion spinal cord. The reduction of serum COX-2 was also decreased. Therefore, GV2 stimulation by yellow laser might enhance the recovery of spinal cord via the increase in BDNF and the decrease in inflammation, apoptosis, and oxidative stress status in the lesion spinal cord.

MiR-30a-5p ameliorates spinal cord injury-induced inflammatory responses and oxidative stress by targeting Neurod 1 through MAPK/ERK signalling

Spinal cord injury (SCI) is a major disability requiring more effective treatment than is currently available. MicroRNAs have been shown to effectively regulate gene expression at the translational level. The aim of the present study was to explore the potential role of miR-30-5p and possible mechanism in SCI. We found that miR-30-5p was notably down-regulated, while Neurod 1 expression was highly elevated in microglia from the mouse model of SCI. Additionally, overexpression of miR-30a-5p significantly suppressed inflammatory responses as reflected by a decrease in the secretion of the cytokines TNF-α, IL-1β and IL-10 triggered by SCI. Furthermore, introduction of miR-30a-5p strengthened the scavenging of oxygen free radicals accompanied by an increase in the expression of SEPN1, TXNL1 and GPX1. More importantly, our study explored that Neurod 1 was a direct and functional target of miR-30a-5p, which was validated by the dual luciferase reporter assay. qRT-PCR and western blot analysis further validated that miR-30a-5p negatively regulated the expression of Neurod 1. Mechanistically, overexpression of miR-30a-5p or silencing of the Neurod 1 gene prevented the MAPK/ERK signalling and inhibited inflammatory responses, meanwhile activated SEPN1, TXNL1 and GPX1. These findings indicate that miR-30a-5p ameliorates inflammatory responses and oxidative stress by targeting Neurod 1 through MAPK/ERK signalling.

Administration of chlorogenic acid alleviates spinal cord injury via TLR4/NF‑κB and p38 signaling pathway anti‑inflammatory activity

Chlorogenic acid, as a secondary metabolite of plants, exhibits a variety of effects including free radical scavenging, antiseptic, anti‑inflammatory and anti‑viral, in addition to its ability to reduce blood glucose, protect the liver and act as an anti‑hyperlipidemic agent and cholagogue. The present study demonstrated that administration of chlorogenic acid alleviated spinal cord injury (SCI) via anti‑inflammatory activity mediated by nuclear factor (NF)‑κB and p38 signaling pathways. Wistar rats were used to structure a SCI model rat to explore the effects of administration of chlorogenic acid on SCI. The Basso, Beattie and Bresnahan test was executed for assessment of neuronal functional recovery and then spinal cord tissue wet/dry weight ratio was recorded. The present study demonstrated that chlorogenic acid increased SCI‑inhibition of BBB scores and decreased SCI‑induction of spinal cord wet/dry weight ratio in rats. In addition, chlorogenic acid suppressed SCI‑induced inflammatory activity, inducible nitric oxide synthase activity and cyclooxygenase‑2 protein expression in the SCI rat. Furthermore, chlorogenic acid suppressed Toll like receptor (TLR)‑4/myeloid differentiation primary response 88 (MyD88)/NF‑κB/IκB signaling pathways and downregulated p38 mitogen activated protein kinase protein expression in SCI rats. The findings suggest that administration of chlorogenic acid alleviates SCI via anti‑inflammatory activity mediated by TLR4/MyD88/NF‑κB and p38 signaling pathways.

The loss-of-function disease-mutation G301R in the Na+/K+-ATPase α2 isoform decreases lesion volume and improves functional outcome after acute spinal cord injury in mice

Background

The Na⁺/K⁺-ATPases are transmembrane ion pumps important for maintenance of ion gradients across the plasma membrane that serve to support multiple cellular functions, such as membrane potentials, regulation of cellular volume and pH, and co-transport of signaling transmitters in all animal cells. The α₂Na⁺/K⁺-ATPase subunit isoform is predominantly expressed in astrocytes, which us the sharp Na⁺-gradient maintained by the sodium pump necessary for astroglial metabolism. Prolonged ischemia induces an elevation of [Na⁺]_i, decreased ATP levels and intracellular pH owing to anaerobic metabolism and lactate accumulation. During ischemia, Na⁺/K⁺-ATPase-related functions will naturally increase the energy demand of the Na⁺/K⁺-ATPase ion pump. However, the role of the α₂Na⁺/K⁺-ATPase in contusion injury to the spinal cord remains unknown. We used mice heterozygous mice for the loss-of-function disease-mutation G301R in the Atp1a2 gene (α₂^+/G301R) to study the effect of reduced α₂Na⁺/K⁺-ATPase expression in a moderate contusion spinal cord injury (SCI) model.

Results

We found that α₂^+/G301R mice display significantly improved functional recovery and decreased lesion volume compared to littermate controls (α₂^+/+) 7 days after SCI. The protein level of the α₁ isoform was significantly increased, in contrast to the α₃ isoform that significantly decreased 3 days after SCI in both α₂^+/G301R and α₂^+/+ mice. The level of the α₂ isoform was significantly decreased in α₂^+/G301R mice both under naïve conditions and 3 days after SCI compared to α₂^+/+ mice. We found no differences in astroglial aquaporin 4 levels and no changes in the expression of chemokines (CCL2, CCL5 and CXCL1) and cytokines (TNF, IL-6, IL-1β, IL-10 and IL-5) between genotypes, just as no apparent differences were observed in location and activation of CD45 and F4/80 positive microglia and infiltrating leukocytes.

Conclusion

Our proof of concept study demonstrates that reduced expression of the α₂ isoform in the spinal cord is protective following SCI. Importantly, the BMS and lesion volume were assessed at 7 days after SCI, and longer time points after SCI were not evaluated. However, the α₂ isoform is a potential possible target of therapeutic strategies for the treatment of SCI.

T1R1/T1R3 Taste Receptor Suppresses Granulocyte-Mediated Neuroinflammation after Spinal Cord Injury

As an active and predominant blood leukocyte population, granulocytes infiltrate into injured spinal cord and produce pro-inflammatory mediators to aggravate neuroinflammation. In the current study, we identify the role of the T1R1/T1R3 receptor in granulocyte-mediated neuroinflammation in a rat spinal cord injury (SCI) model. We found that T1R1 and T1R3 were substantially expressed in both circulating and infiltrating granulocytes. In vitro stimulation of T1R1/T1R3 receptor with L-serine notably reduced production of reactive oxygen species (ROS) and several pro-inflammatory cytokines. To evaluate the role of T1R1/T1R3 receptor in vivo, gurmarin, a selective T1R3 inhibitor, was injected into rats before and after SCI. Gurmarin administration significantly upregulated expression of interleukin (IL)-1β, IL-6, myeloperoxidase, and matrix metallopeptidase 9, as well as production of ROS in infiltrating granulocytes. Signal pathway analysis revealed that gurmarin promoted nuclear factor (NF)-κβ signaling in infiltrating granulocytes. Consistently, cell apoptosis and inflammatory mediator levels at the injury sites were increased by gurmarin, together with higher T lymphocyte recruitment. Our research indicates that the T1R1/T1R3 receptor is an anti-inflammatory receptor for infiltrating granulocytes after SCI. Simulation of T1R1/T1R3 receptor might be a prospective, or at least a supplemental, therapeutic approach to controlling neuroinflammation to promote functional recovery.

Genetic Ablation of Soluble TNF Does Not Affect Lesion Size and Functional Recovery after Moderate Spinal Cord Injury in Mice

Traumatic spinal cord injury (SCI) is followed by an instant increase in expression of the microglial-derived proinflammatory cytokine tumor necrosis factor (TNF) within the lesioned cord. TNF exists both as membrane-anchored TNF (mTNF) and as cleaved soluble TNF (solTNF). We previously demonstrated that epidural administration of a dominant-negative inhibitor of solTNF, XPro1595, to the contused spinal cord resulted in changes in Iba1 protein expression in microglia/macrophages, decreased lesion volume, and improved locomotor function. Here, we extend our studies using mice expressing mTNF, but no solTNF (mTNF^Δ/Δ), to study the effect of genetic ablation of solTNF on SCI. We demonstrate that TNF levels were significantly decreased within the lesioned spinal cord 3 days after SCI in mTNF^Δ/Δ mice compared to littermates. This decrease did, however, not translate into significant changes in other pro- and anti-inflammatory cytokines (IL-10, IL-1β, IL-6, IL-5, IL-2, CXCL1, CCL2, or CCL5), despite a tendency towards increased IL-10 and decreased IL-1β, TNFR1, and TNFR2 levels in mTNF^Δ/Δ mice. In addition, microglial and leukocyte infiltration, activation state (Iba1, CD11b, CD11c, CD45, and MHCII), lesion size, and functional outcome after moderate SCI were comparable between genotypes. Collectively, our data demonstrate that genetic ablation of solTNF does not significantly modulate postlesion outcome after SCI.

Recombinant Human Annexin A5 Can Repair the Disrupted Cardiomyocyte Adherens Junctions in Endotoxemia

Recombinant human annexin A5 (Anx5) is known to protect cardiac function during endotoxemia, although the underlying mechanisms have yet to be elucidated. In this study, we demonstrated that Anx5 could repair the disrupted cardiomyocyte adherens junctions and improve the myocardial contractile function in lipopolysaccharide (LPS)-induced endotoxemia. Mechanistic studies revealed that Anx5 could antagonize the disassociation between p120-catenin (p120) and N-cadherin as well as the dephosphorylation of p120 in LPS-treated cardiomyocytes. Small interference RNA and specific inhibitors experiment demonstrated that Anx5 regulated p120 functions by inhibition of p21-activated kinase 5 in a protein kinase Cα-dependent way. Moreover, Anx5 could inhibit nuclear factor κB activation and downregulate the level of inflammatory cytokines, such as tumor necrosis factor α and interleukin 1β, which contributed to improving tissue pathological damage in LPS-induced mouse endotoxemia model. Taken together, Anx5 could protect cardiomyocytes adherens junctions and improve myocardial contractile function via regulation of p120 and anti-inflammation in LPS-induced endotoxemia. This study provided novel insights in the prevention and treatment of septic shock.

Early Detection of Pressure Ulcer Development Following Traumatic Spinal Cord Injury Using Inflammatory Mediators

OBJECTIVE

To identify changes in concentrations of inflammatory mediators in plasma and urine after traumatic spinal cord injury (SCI) and before the occurrence of a first pressure ulcer.

DESIGN

Retrospective; secondary analysis of existing data.

SETTING

Acute hospitalization and inpatient rehabilitation sites at a university medical center.

PARTICIPANTS

Individuals with a pressure ulcer and plasma samples (n=17) and individuals with a pressure ulcer and urine samples (n=15) were matched by age and plasma/urine sample days to individuals with SCI and no pressure ulcer (N=35).

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

Plasma and urine samples were assayed in patients with SCI, capturing samples within 4 days after the SCI to a week before the formation of the first pressure ulcer. The Wilcoxon signed-rank test was performed to identify changes in the inflammatory mediators between the 2 time points.

RESULTS

An increase in concentration of the chemokine interferon-γ-induced protein of 10kd/CXCL10 in plasma (P<.01) and a decrease in concentration of the cytokine interferon-α in urine (P=.01) were observed before occurrence of a first pressure ulcer (∼4d) compared with matched controls.

CONCLUSIONS

Altered levels of inflammatory mediators in plasma and urine may be associated with pressure ulcer development after traumatic SCI. These inflammatory mediators should be explored as possible biomarkers for identifying individuals at risk for pressure ulcer formation.

Applications of the Keap1-Nrf2 system for gene and cell therapy

Oxidative stress has been implicated to play a role in a number of acute and chronic diseases including acute injuries of the central nervous system, neurodegenerative and cardiovascular diseases, and cancer. The redox-activated transcription factor Nrf2 has been shown to protect many different cell types and organs from a variety of toxic insults, whereas in many cancers, unchecked Nrf2 activity increases the expression of cytoprotective genes and, consequently, provides growth advantage to cancerous cells. Herein, we discuss current preclinical gene therapy approaches to either increase or decrease Nrf2 activity with a special reference to neurological diseases and cancer. In addition, we discuss the role of Nrf2 in stem cell therapy for neurological disorders.

Age decreases macrophage IL-10 expression: Implications for functional recovery and tissue repair in spinal cord injury

Macrophages with different activation states are present after spinal cord injury (SCI). M1 macrophages purportedly promote secondary injury processes while M2 cells support axon growth. The average age at the time of SCI has increased in recent decades, however, little is known about how different physiological factors contribute to macrophage activation states after SCI. Here we investigate the effect of age on IL-10, a key indicator of M2 macrophage activation. Following mild-moderate SCI in 4 and 14 month old (MO) mice we detected significantly reduced IL-10 expression with age in the injured spinal cord. Specifically, CD86/IL-10 positive macrophages, also known as M2b or regulatory macrophages, were reduced in 14 vs. 4 MO SCI animals. This age-dependent shift in macrophage phenotype was associated with impaired functional recovery and enhanced tissue damage in 14-month-old SCI mice. In vitro, M2b macrophages release anti-inflammatory cytokines without causing neurotoxicity, suggesting that imbalances in the M2b response in 14-month-old mice may be contributing to secondary injury processes. Our data indicate that age is an important factor that regulates SCI inflammation and recovery even to mild-moderate injury. Further, alterations in macrophage activation states may contribute to recovery and we have identified the M2b phenotype as a potential target for therapeutic intervention.

Carnosol protects against spinal cord injury through Nrf-2 upregulation

BACKGROUND

Carnosol is an ortho-diphenolic diterpene with excellent antioxidant potential. The present study was designed to identify the protective role of carnosol against spinal cord injury (SCI)-induced oxidative stress and inflammation in Wistar rats.

METHODS

In the present study, oxidative stress status was determined through estimating total antioxidant capacity, total oxidant status, lipid peroxide content, protein carbonyl and sulfhydryl levels, reactive oxygen species (ROS), antioxidant status (superoxide-dismutase, catalase, glutathione, glutathione peroxidase, glutathione-S-transferase). Inflammatory effects were determined by analyzing the expression of NF-κB and COX-2 through Western blot analysis. Further, carnosol-mediated redox homeostasis was analyzed by determining p-AKT and Nrf-2 levels.

RESULTS

SCI resulted in a significant increase in oxidative stress status through increased ROS generation, total oxidant levels, lipid peroxide content, protein carbonyl and sulfhydryl levels. The antioxidant status in SCI rats was significantly reduced, indicating imbalance in redox status. In addition, the expression of NF-κB and COX-2 was significantly upregulated, while p-AKT and Nrf-2 levels were downregulated in SCI rats. However, treatment with carnosol showed a significant enhancement in the antioxidant status with concomitant decline in oxidative stress parameters. Further, carnosol treatment regulated the key proteins in inflammation and redox status through significant downregulation of NF-κB and COX-2 levels and upregulation of p-AKT and Nrf-2 expression.

CONCLUSION

Thus, the present study shows for the first time on the protective role of carnosol against SCI-induced oxidative stress and inflammation through modulating NF-κB, COX-2 and Nrf-2 levels in Wistar rats.

From demyelination to remyelination: the road toward therapies for spinal cord injury

Myelin integrity is crucial for central nervous system (CNS) physiology while its preservation and regeneration after spinal cord injury (SCI) is key to functional restoration. Disturbance of nodal organization acutely after SCI exposes the axon and triggers conduction block in the absence of overt demyelination. Oligodendrocyte (OL) loss and myelin degradation follow as a consequence of secondary damage. Here, we provide an overview of the major biological events and underlying mechanisms leading to OL death and demyelination and discuss strategies to restrain these processes. Another aspect which is critical for SCI repair is the enhancement of endogenously occurring spontaneous remyelination. Recent findings have unveiled the complex roles of innate and adaptive immune responses in remyelination and the immunoregulatory potential of the glial scar. Moreover, the intimate crosstalk between neuronal activity, oligodendrogenesis and myelination emphasizes the contribution of rehabilitation to functional recovery. With a view toward clinical applications, several therapeutic strategies have been devised to target SCI pathology, including genetic manipulation, administration of small therapeutic molecules, immunomodulation, manipulation of the glial scar and cell transplantation. The implementation of new tools such as cellular reprogramming for conversion of one somatic cell type to another or the use of nanotechnology and tissue engineering products provides additional opportunities for SCI repair. Given the complexity of the spinal cord tissue after injury, it is becoming apparent that combinatorial strategies are needed to rescue OLs and myelin at early stages after SCI and support remyelination, paving the way toward clinical translation.

Efficacy of some non-conventional herbal medications (sulforaphane, tanshinone IIA, and tetramethylpyrazine) in inducing neuroprotection in comparison with interleukin-10 after spinal cord injury: A meta-analysis

CONTEXT

Inflammation after spinal cord injury (SCI) may be responsible for further neural damages and therefore inhibition of inflammatory processes may exert a neuroprotection effect.

OBJECTIVES

To assess the efficacy of some non-conventional herbal medications including sulforaphane, tanshinone IIA, and tetramethylpyrazine in reducing inflammation and compare them with a known effective anti-inflammatory agent (interleukin-10 (IL-10)).

METHODS

We searched relevant articles in Ovid database, Medline (PubMed) EMBASE, Google Scholar, Cochrane, and Scopus up to June 2013. The efficacy of each treatment and study powers were compared using random effects model of meta-analysis. To our knowledge, no conflict of interest exists.

RESULTS

Eighteen articles entered into the study. The meta-analysis revealed that exogenous IL-10 was more effective in comparison with the mentioned herbal extracts. The proposed pathways for each medication's effect on reducing the inflammation process are complex and many overlaps may exist.

CONCLUSION

IL-10 has a strong effect in the induction of neuroprotection and neurorecovery after SCI by multiple pathways. Tetramethylpyrazine has an acceptable influence in reducing inflammation through the up-regulation of IL-10. Outcomes of sulforaphane and tanshinone IIA administration are acceptable but still weaker than IL-10.

Cytokine pathways regulating glial and leukocyte function after spinal cord and peripheral nerve injury

Injury to the nervous system causes the almost immediate release of cytokines by glial cells and neurons. These cytokines orchestrate a complex array of responses leading to microgliosis, immune cell recruitment, astrogliosis, scarring, and the clearance of cellular debris, all steps that affect neuronal survival and repair. This review will focus on cytokines released after spinal cord and peripheral nerve injury and the primary signalling pathways triggered by these inflammatory mediators. Notably, the following cytokine families will be covered: IL-1, TNF, IL-6-like, TGF-β, and IL-10. Whether interfering with cytokine signalling could lead to novel therapies will also be discussed. Finally, the review will address whether manipulating the above-mentioned cytokine families and signalling pathways could exert distinct effects in the injured spinal cord versus peripheral nerve.

Receptor for advanced glycation end products (RAGE) and its ligands: focus on spinal cord injury

Spinal cord injury (SCI) results in neuronal and glial death and the loss of axons at the injury site. Inflammation after SCI leads to the inhibition of tissue regeneration and reduced neuronal survival. In addition, the loss of axons after SCI results in functional loss below the site of injury accompanied by neuronal cell body's damage. Consequently, reducing inflammation and promoting axonal regeneration after SCI is a worthy therapeutic goal. The receptor for advanced glycation end products (RAGE) is a transmembrane protein and receptor of the immunoglobulin superfamily. RAGE is implicated in inflammation and neurodegeneration. Several recent studies demonstrated an association between RAGE and central nervous system disorders through various mechanisms. However, the relationship between RAGE and SCI has not been shown. It is imperative to elucidate the association between RAGE and SCI, considering that RAGE relates to inflammation and axonal degeneration following SCI. Hence, the present review highlights recent research regarding RAGE as a compelling target for the treatment of SCI.

Inducible protein-10, a potential driver of neurally controlled interleukin-10 and morbidity in human blunt trauma

OBJECTIVE

Blunt trauma and traumatic spinal cord injury induce systemic inflammation that contributes to morbidity. Dysregulated neural control of systemic inflammation postinjury is likely exaggerated in patients with traumatic spinal cord injury. We used in silico methods to discern dynamic inflammatory networks that could distinguish systemic inflammation in traumatic spinal cord injury from blunt trauma.

DESIGN

Retrospective study.

SETTINGS

Tertiary care institution.

PATIENTS

Twenty-one severely injured thoracocervical traumatic spinal cord injury patients and matched 21 severely injured blunt trauma patients without spinal cord injury.

INTERVENTION

None.

MEASUREMENTS AND MAIN RESULTS

Serial blood samples were obtained from days 1 to 14 postinjury. Twenty-four plasma inflammatory mediators were quantified. Statistical significance between the two groups was determined by two-way analysis of variance. Dynamic Bayesian network inference was used to suggest dynamic connectivity and central inflammatory mediators. Circulating interleukin-10 was significantly elevated in thoracocervical traumatic spinal cord injury group versus non-spinal cord injury group, whereas interleukin-1β, soluble interleukin-2 receptor-α, interleukin-4, interleukin-5, interleukin-7, interleukin-13, interleukin-17, macrophage inflammatory protein 1α and 1β, granulocyte-macrophage colony-stimulating factor, and interferon-γ were significantly reduced in traumatic spinal cord injury group versus non-spinal cord injury group. Dynamic Bayesian network suggested that post-spinal cord injury interleukin-10 is driven by inducible protein-10, whereas monocyte chemotactic protein-1 was central in non-spinal cord injury dynamic networks. In a separate validation cohorts of 356 patients without spinal cord injury and 85 traumatic spinal cord injury patients, individuals with plasma inducible protein-10 levels more than or equal to 730 pg/mL had significantly prolonged hospital and ICU stay and days on mechanical ventilator versus patients with plasma inducible protein-10 level less than 730 pg/mL.

CONCLUSION

This is the first study to compare the dynamic systemic inflammatory responses of traumatic spinal cord injury patients versus patients without spinal cord injury, suggesting a key role for inducible protein-10 in driving systemic interleukin-10 and morbidity and highlighting the potential utility of in silico tools to identify key inflammatory drivers.