Targeting inflammation to influence mood following spinal cord injury: a randomized clinical trial

Old age alters inflammation and autophagy signaling in the brain, leading to exacerbated neurological outcomes after spinal cord injury in male mice

Older patients with spinal cord injury (SCI) have different features with regard to neurological characteristics after injury. Recent large-scale longitudinal population-based studies showed that individuals with SCI are at a higher risk of developing dementia than non-SCI patients, indicating that SCI is a potential risk factor for dementia. Aging is known to potentiate inflammation and neurodegeneration at the injured site leading to impaired recovery from SCI. However, no research has been aimed at studying the mechanisms of SCI-mediated cognitive impairment in the elderly. The present study examined neurobehavioral and molecular changes in the brain and the underlying mechanisms associated with brain dysfunction in aged C57BL/6 male mice using a contusion SCI model. At 2 months post-injury, aged mice displayed worse performance in locomotor, cognitive and depressive-like behavioral tests compared to young adult animals. Histopathology in injured spinal cord tissue was exacerbated in aged SCI mice. In the brain, transcriptomic analysis with NanoString neuropathology panel identified activated microglia and dysregulated autophagy as the most significantly altered pathways by both age and injury. These findings were further validated by flow cytometry, which demonstrated increased myeloid and lymphocytes infiltration at both the injured site and brain of aged mice. Moreover, SCI in aged mice altered microglial function and dysregulated autophagy in microglia, resulting in worsened neurodegeneration. Taken together, our data indicate that old age exacerbates neuropathological changes in both the injured spinal cord and remote brain regions leading to poorer functional outcomes, at least in part, through altered inflammation and autophagy function.

Role of NLRP3 Inflammasome in Post-Spinal-Cord-Injury Anxiety and Depression: Molecular Mechanisms and Therapeutic Implications

The majority of research on the long-term effects of spinal cord injury (SCI) has primarily focused on neuropathic pain (NP), psychological issues, and sensorimotor impairments. Among SCI patients, mood disorders, such as anxiety and depression, have been extensively studied. It has been found that chronic stress and NP have negative consequences and reduce the quality of life for individuals living with SCI. Our review examined both human and experimental evidence to explore the connection between mood changes following SCI and inflammatory pathways, with a specific focus on NLRP3 inflammasome signaling. We observed increased proinflammatory factors in the blood, as well as in the brain and spinal cord tissues of SCI models. The NLRP3 inflammasome plays a crucial role in various diseases by controlling the release of proinflammatory molecules like interleukin 1β (IL-1β) and IL-18. Dysregulation of the NLRP3 inflammasome in key brain regions associated with pain processing, such as the prefrontal cortex and hippocampus, contributes to the development of mood disorders following SCI. In this review, we summarized recent research on the expression and regulation of components related to NLRP3 inflammasome signaling in mood disorders following SCI. Finally, we discussed potential therapeutic approaches that target the NLRP3 inflammasome and regulate proinflammatory cytokines as a way to treat mood disorders following SCI.

Reducing endocrine metabolic disease risk in adults with chronic spinal cord injury: strategic activities conducted by the Ontario-Quebec RIISC team

PURPOSE

The Rehabilitation Interventions for Individuals with a Spinal Cord Injury in the Community (RIISC) team aimed to develop and evaluate innovative rehabilitation interventions to identify endocrine metabolic disease (EMD) risk, intending to reduce the frequency and severity of EMD related morbidity and mortality among adults living with chronic spinal cord injury or disease (SCI/D).

MATERIALS AND METHODS

An interprovincial team from Ontario and Quebec reviewed available EMD literature and evidence syntheses and completed an inventory of health services, policies and practices in SCI/D care. The review outcomes were combined with expert opinion to create an EMD risk model to inform health service transformation.

RESULTS

EMD risk and mortality are highly prevalent among adults with chronic SCI/D. In stark contrast, few rehabilitation interventions target EMD outcomes. The modelled solution proposes: 1) abandoning single-disease paradigms and examining a holistic perspective of the individual's EMD risk, and 2) developing and disseminating practice-based research approaches in outpatient community settings.

CONCLUSIONS

RIISC model adoption could accelerate EMD care optimization, and ultimately inform the design of large-scale longitudinal pragmatic trials likely to improve health outcomes. Linking the RIISC team activities to economic evaluations and policy deliverables will strengthen the relevance and impact among policymakers, health care providers and patients.

Cognitive and physical impairment in spinal cord injury: A scoping review and call for new understanding

Study Design: Scoping review.Objective: To examine potential underlying mechanisms of cognitive and physical impairment in patients with spinal cord injury and identify current research gaps.Methods: A scoping review of the literature was conducted following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) extension for scoping reviews to identify primary studies that explored mechanisms of cognitive and/or physical impairment after spinal cord injury. The databases searched were PubMed/MEDLINE, EMBASE (OVID), Cumulative Index to Nursing and Allied Health Literature (CINAHL; EBSCO), Web of Science, Scopus, and PsycInfo. These databases were searched from inception through December 20, 2021.Results: Accumulating research suggests that neuroinflammation and neurodegeneration after a traumatic event may be possible mechanisms for cognitive impairment among patients with SCI. In addition, lack of physical activity due to impaired mobility is associated with an increased risk of cognitive impairment.Conclusion: While the results establish a foundation for understanding how cognitive impairment, mental health, and physical function independently affect patients with SCI, further research is warranted to understand how these factors systemically impact the patient and discover refined targets for future rehabilitation therapies. Studies should also explore potential predisposing factors for the relationship between cognitive and physical impairment among patients with SCI.

Mapping of Dietary Interventions Beneficial in the Prevention of Secondary Health Conditions in Spinal Cord Injured Population: A Systematic Review

OBJECTIVES

Individuals with spinal cord injury are at risk of secondary health conditions (SHC) that develop as a consequence of autonomic dysfunction, prolonged oxidative stress and inflammation, and physical inactivity coupled with inadequate energy and nutritional intake. SHC can be debilitating and even life-threatening, and its prevention remains one of the major challenges in the continuum of medical care of aging SCI population. An unhealthy diet is a major driver of inflammation, oxidative stress, and unfavourable metabolic status and may be a practical preventive target to tackle increased SHC risk post-injury.

AIMS

To provide a catalogue of dietary interventions beneficial in prevention of SHC among individuals with SCI by conducting a systematic review of the literature on dietary interventions and dietary supplementation in promoting health and well-being after the injury. In addition, we aimed to provide a summary of observational studies exploring the association between habitual diet (macro- and micronutrients intake and dietary patterns) and health patterns following the injury.

METHOD

This review was registered at PROSPERO (University of York) with registration number CRD42022373773. Four medical databases (EMBASE.com, MEDLINE [Ovid], Cochrane CENTRAL, and Web of Science Core Collection) and Google Scholar were searched from inception until 11th July 2022. Studies were included if they were clinical trials or observational studies conducted in adult individuals with SCI and provided information of interest. Based on strength of the study design and risk of bias assessment (using the NIH tool), we classified studies from Level 1 (most reliable studies) to Level 4 (least reliable studies).

RESULTS

Of 12,313 unique citations, 47 articles (based on 43 original studies) comprising 32 interventional (22 RCTs, 3 NRCT, and 7 pre-post studies) and 11 observational studies (2 cohort studies, 2 case-control, 1 post-intervention follow-up study, and 6 cross-sectional studies) were included in the present systematic review. Twenty studies (46.5%) were classified as Level 1 or 2, indicating high/moderate methodological quality. Based on those studies, dietary strategies including high protein diet, intermittent fasting, balanced diet in combination with physical conditioning and electrical stimulation, and dietary supplementation including alpha-lipoic acid, creatine, vitamin D, and cranberry-derived supplements and probiotics were mapped as the most promising in prevention of SHC among individuals with SCI.

CONCLUSIONS

To develop timely and effective preventive strategies targeting major SHC (e.g., cardiometabolic diseases, urinary tract infections) in SCI, further research is warranted to confirm the effectiveness of dietary strategies/interventions identified through the current systematic review of the literature.

Systemic inflammation after spinal cord injury: A review of biological evidence, related health risks, and potential therapies

Individuals with chronic traumatic spinal cord injury (SCI) develop progressive multi-system health problems that result in clinical illness and disability. Systemic inflammation is associated with many of the common medical complications and acquired diseases that accompany chronic SCI, suggesting that it contributes to a number of comorbid pathological conditions. However, many of the mechanisms that promote persistent systemic inflammation and its consequences remain ill-defined. This review describes the significant biological factors that contribute to systemic inflammation, major organ systems affected, health risks, and the potential treatment strategies. We aim to highlight the need for a better understanding of inflammatory processes, and to establish appropriate strategies to address inflammation in SCI.

Kynurenine metabolism is altered in mdx mice: A potential muscle to brain connection

NEW FINDINGS

Research has shown that promoting muscle health with regular aerobic exercise can improve mental health through a kynurenine metabolic pathway. With regular aerobic exercise, kynurenine metabolism is favourably altered towards a neuroprotective pathway that promotes kynurenic acid production through increased expression of PGC-1α, kynurenine amino acid transferase (KAT) enzymes, and lowered inflammation. Whether conditions of muscle disease such as muscular dystrophy can negatively influence this pathway remains unknown. We show that the DBA/2J mdx model of Duchenne muscular dystrophy exhibit altered kynurenine metabolism with less KYNA and PGC-1α and the highest level of TNF-a mRNA - results associated with anxiety-like behaviour.

ABSTRACT

Regular exercise can direct muscle kynurenine (KYN) metabolism toward the neuroprotective branch of the kynurenine pathway thereby limiting the accumulation of neurotoxic metabolites in the brain and contributing to mental resilience. However, the effect of muscle disease on KYN metabolism has not yet been investigated. Previous work has highlighted anxiety-like behaviors in approximately 25% of patients with Duchenne muscular dystrophy (DMD), possibly due to altered KYN metabolism. Here, we characterized KYN metabolism in mdx mouse models of DMD. Young (8-10 week old) DBA/2J (D2) mdx mice, but not age-matched C57BL/10 (C57) mdx mice, had lower levels of circulating KYNA and KYNA:KYN ratio compared with their respective wild-type (WT) controls. While both C57 and D2 mdx mice displayed signs of anxiety-like behaviour, spending more time in the corners of the arena during a novel object recognition test, this effect was more prominent in D2 mdx mice. Correlational analysis detected a significant negative association between KYNA:KYN levels and time spent in corners in D2 mice, but not C57 mice. In extensor digitorum longus muscles from D2 mdx mice, but not C57 mdx mice, we found lowered protein levels of peroxisome proliferator-activated receptor-gamma coactivator 1-alpha and kynurenine amino transferase-1 enzyme when compared with WT. Furthermore, D2 mdx quadricep muscles had the highest level of TNF-α expression, which is suggestive of enhanced inflammation. Thus, our pilot work shows that KYN metabolism is altered in D2 mdx mice, with a potential contribution from altered muscle health. This article is protected by copyright. All rights reserved.

Breaking Mental Barriers Promotes Recovery After Spinal Cord Injury

Functional recovery after spinal cord injury (SCI) often proves difficult as physical and mental barriers bar survivors from enacting their designated rehabilitation programs. We recently demonstrated that adult mice administered gabapentinoids, clinically approved drugs prescribed to mitigate chronic neuropathic pain, recovered upper extremity function following cervical SCI. Given that rehabilitative training enhances neuronal plasticity and promotes motor recovery, we hypothesized that the combination of an aerobic-based rehabilitation regimen like treadmill training with gabapentin (GBP) administration will maximize recovery in SCI mice by strengthening synaptic connections along the sensorimotor axis. Whereas mice administered GBP recovered forelimb functions over the course of weeks and months following SCI, no additive forelimb recovery as the result of voluntary treadmill training was noted in these mice. To our surprise, we also failed to find an additive effect in mice administered vehicle. As motivation is crucial in rehabilitation interventions, we scored active engagement toward the rehabilitation protocol and found that mice administered GBP were consistently participating in the rehabilitation program. In contrast, mice administered vehicle exhibited a steep decline in participation, especially at chronic time points. Whereas neuroinflammatory gene expression profiles were comparable between experimental conditions, we discovered that mice administered GBP had increased hippocampal neurogenesis and exhibited less anxiety-like behavior after SCI. We also found that an external, social motivator effectively rescues participation in mice administered vehicle and promotes forelimb recovery after chronic SCI. Thus, not only does a clinically relevant treatment strategy preclude the deterioration of mental health after chronic SCI, but group intervention strategies may prove to be physically and emotionally beneficial for SCI individuals.

Hippocampal Mitochondrial Abnormalities Induced the Dendritic Complexity Reduction and Cognitive Decline in a Rat Model of Spinal Cord Injury

Spinal cord injury (SCI) is a progressive neurodegenerative disease in addition to a traumatic event. Cognitive dysfunction following SCI has been widely reported in patients and animal models. However, the neuroanatomical changes affecting cognitive function after SCI, as well as the mechanisms behind these changes, have so far remained elusive. Herein, we found that SCI accelerates oxidative stress damage of hippocampal neuronal mitochondria. Then, for the first time, we presented a three-dimensional morphological atlas of rat hippocampal neurons generated using a fluorescence Micro-Optical Sectioning Tomography system, a method that accurately identifies the spatial localization of neurons and trace neurites. We showed that the number of dendritic branches and dendritic length was decreased in late stage of SCI. Western blot and transmission electron microscopy analyses also showed a decrease in synaptic communication. In addition, a battery of behavioral tests in these animals revealed hippocampal based cognitive dysfunction, which could be attributed to changes in the dendritic complexity of hippocampal neurons. Taken together, these results suggested that mitochondrial abnormalities in hippocampal neurons induced the dendritic complexity reduction and cognitive decline following SCI. Our study highlights the neuroanatomical basis and importance of mitochondria in brain degeneration following SCI, which might contribute to propose new therapeutic strategies.

Antioxidant Therapy in Oxidative Stress-Induced Neurodegenerative Diseases: Role of Nanoparticle-Based Drug Delivery Systems in Clinical Translation

Free radicals are formed as a part of normal metabolic activities but are neutralized by the endogenous antioxidants present in cells/tissue, thus maintaining the redox balance. This redox balance is disrupted in certain neuropathophysiological conditions, causing oxidative stress, which is implicated in several progressive neurodegenerative diseases. Following neuronal injury, secondary injury progression is also caused by excessive production of free radicals. Highly reactive free radicals, mainly the reactive oxygen species (ROS) and reactive nitrogen species (RNS), damage the cell membrane, proteins, and DNA, which triggers a self-propagating inflammatory cascade of degenerative events. Dysfunctional mitochondria under oxidative stress conditions are considered a key mediator in progressive neurodegeneration. Exogenous delivery of antioxidants holds promise to alleviate oxidative stress to regain the redox balance. In this regard, natural and synthetic antioxidants have been evaluated. Despite promising results in preclinical studies, clinical translation of antioxidants as a therapy to treat neurodegenerative diseases remains elusive. The issues could be their low bioavailability, instability, limited transport to the target tissue, and/or poor antioxidant capacity, requiring repeated and high dosing, which cannot be administered to humans because of dose-limiting toxicity. Our laboratory is investigating nanoparticle-mediated delivery of antioxidant enzymes to address some of the above issues. Apart from being endogenous, the main advantage of antioxidant enzymes is their catalytic mechanism of action; hence, they are significantly more effective at lower doses in detoxifying the deleterious effects of free radicals than nonenzymatic antioxidants. This review provides a comprehensive analysis of the potential of antioxidant therapy, challenges in their clinical translation, and the role nanoparticles/drug delivery systems could play in addressing these challenges.

Effects of Polyphenols on Oxidative Stress, Inflammation, and Interconnected Pathways during Spinal Cord Injury

Despite the progression in targeting the complex pathophysiological mechanisms of neurodegenerative diseases (NDDs) and spinal cord injury (SCI), there is a lack of effective treatments. Moreover, conventional therapies suffer from associated side effects and low efficacy, raising the need for finding potential alternative therapies. In this regard, a comprehensive review was done regarding revealing the main neurological dysregulated pathways and providing alternative therapeutic agents following SCI. From the mechanistic point, oxidative stress and inflammatory pathways are major upstream orchestras of cross-linked dysregulated pathways (e.g., apoptosis, autophagy, and extrinsic mechanisms) following SCI. It urges the need for developing multitarget therapies against SCI complications. Polyphenols, as plant-derived secondary metabolites, have the potential of being introduced as alternative therapeutic agents to pave the way for treating SCI. Such secondary metabolites presented modulatory effects on neuronal oxidative stress, neuroinflammatory, and extrinsic axonal dysregulated pathways in the onset and progression of SCI. In the present review, the potential role of phenolic compounds as critical phytochemicals has also been revealed in regulating upstream dysregulated oxidative stress/inflammatory signaling mediators and extrinsic mechanisms of axonal regeneration after SCI in preclinical and clinical studies. Additionally, the coadministration of polyphenols and stem cells has shown a promising strategy for improving post-SCI complications.

Tryptophan Metabolism in Central Nervous System Diseases: Pathophysiology and Potential Therapeutic Strategies

The metabolism of L-tryptophan (TRP) regulates homeostasis, immunity, and neuronal function. Altered TRP metabolism has been implicated in the pathophysiology of various diseases of the central nervous system. TRP is metabolized through two main pathways, the kynurenine pathway and the methoxyindole pathway. First, TRP is metabolized to kynurenine, then kynurenic acid, quinolinic acid, anthranilic acid, 3-hydroxykynurenine, and finally 3-hydroxyanthranilic acid along the kynurenine pathway. Second, TRP is metabolized to serotonin and melatonin along the methoxyindole pathway. In this review, we summarize the biological properties of key metabolites and their pathogenic functions in 12 disorders of the central nervous system: schizophrenia, bipolar disorder, major depressive disorder, spinal cord injury, traumatic brain injury, ischemic stroke, intracerebral hemorrhage, multiple sclerosis, Alzheimer's disease, Parkinson's disease, amyotrophic lateral sclerosis, and Huntington's disease. Furthermore, we summarize preclinical and clinical studies, mainly since 2015, that investigated the metabolic pathway of TRP, focusing on changes in biomarkers of these neurologic disorders, their pathogenic implications, and potential therapeutic strategies targeting this metabolic pathway. This critical, comprehensive, and up-to-date review helps identify promising directions for future preclinical, clinical, and translational research on neuropsychiatric disorders.

Inflammation increases the development of depression behaviors in male rats after spinal cord injury

Following spinal cord injury, 18-26% of patients are diagnosed with depressive disorders, compared to 8-12% in the general population. As increased inflammation strongly correlates with depression in both animal and human studies, we hypothesized that the immune activation inherent to SCI could increase depression-like behavior. Thus, we proposed that reducing immune activation with minocycline, a microglial inhibitor, would decrease depression-like behavior following injury. Male Sprague-Dawley rats were given minocycline in their drinking water for 14 days following a moderate, mid-thoracic (T12) spinal contusion. An array of depression-like behaviors (social activity, sucrose preference, forced swim, open field activity) were examined prior to injury as well as on days 9-10, 19-20, and 29-30 post-injury. Peripheral cytokine levels were analyzed in serum collected prior to injury and 10 days post-injury. Hierarchical cluster analysis divided subjects into two groups based on behavior: depressed and not-depressed. Depressed subjects displayed lower levels of open field activity and social interaction relative to their not-depressed counterparts. Depressed subjects also showed significantly greater expression of pro-inflammatory cytokines both before and after injury and displayed lower levels of hippocampal neurogenesis than not-depressed subjects. Intriguingly, subjects who later showed depressive behaviors had higher baseline levels of the pro-inflammatory cytokine IL-6, which persisted throughout the duration of the experiment. Minocycline, however, did not affect serum cytokine levels and did not block the development of depression; equal numbers of minocycline versus vehicle-treated subjects appeared in both phenotypic groups. Despite this, these data overall suggest that molecular correlates of inflammation prior to injury could predict the development of depression after a physical stressor.

Neuroimmune Mechanisms as Novel Treatment Targets for Substance Use Disorders and Associated Comorbidities

Recent studies examining the neurobiology of substance abuse have revealed a significant role of neuroimmune signaling as a mechanism through which drugs of abuse induce aberrant changes in synaptic plasticity and contribute to substance abuse-related behaviors. Immune signaling within the brain and the periphery critically regulates homeostasis of the nervous system. Perturbations in immune signaling can induce neuroinflammation or immunosuppression, which dysregulate nervous system function including neural processes associated with substance use disorders (SUDs). In this review, we discuss the literature that demonstrates a role of neuroimmune signaling in regulating learning, memory, and synaptic plasticity, emphasizing specific cytokine signaling within the central nervous system. We then highlight recent preclinical studies, within the last 5 years when possible, that have identified immune mechanisms within the brain and the periphery associated with addiction-related behaviors. Findings thus far underscore the need for future investigations into the clinical potential of immunopharmacology as a novel approach toward treating SUDs. Considering the high prevalence rate of comorbidities among those with SUDs, we also discuss neuroimmune mechanisms of common comorbidities associated with SUDs and highlight potentially novel treatment targets for these comorbid conditions. We argue that immunopharmacology represents a novel frontier in the development of new pharmacotherapies that promote long-term abstinence from drug use and minimize the detrimental impact of SUD comorbidities on patient health and treatment outcomes.

Severe Spinal Cord Injury in Rats Induces Chronic Changes in the Spinal Cord and Cerebral Cortex Metabolism, Adjusted by Thiamine That Improves Locomotor Performance

Our study aims at developing knowledge-based strategies minimizing chronic changes in the brain after severe spinal cord injury (SCI). The SCI-induced long-term metabolic alterations and their reactivity to treatments shortly after the injury are characterized in rats. Eight weeks after severe SCI, significant mitochondrial lesions outside the injured area are demonstrated in the spinal cord and cerebral cortex. Among the six tested enzymes essential for the TCA cycle and amino acid metabolism, mitochondrial 2-oxoglutarate dehydrogenase complex (OGDHC) is the most affected one. SCI downregulates this complex by 90% in the spinal cord and 30% in the cerebral cortex. This is associated with the tissue-specific changes in other enzymes of the OGDHC network. Single administrations of a pro-activator (thiamine, or vitamin B1, 1.2 mmol/kg) or a synthetic pro-inhibitor (triethyl glutaryl phosphonate, TEGP, 0.02 mmol/kg) of OGDHC within 15–20 h after SCI are tested as protective strategies. The biochemical and physiological assessments 8 weeks after SCI reveal that thiamine, but not TEGP, alleviates the SCI-induced perturbations in the rat brain metabolism, accompanied by the decreased expression of (acetyl)p53, increased expression of sirtuin 5 and an 18% improvement in the locomotor recovery. Treatment of the non-operated rats with the OGDHC pro-inhibitor TEGP increases the p53 acetylation in the brain, approaching the brain metabolic profiles to those after SCI. Our data testify to an important contribution of the OGDHC regulation to the chronic consequences of SCI and their control by p53 and sirtuin 5.

Inducing inflammation following subacute spinal cord injury in female rats: A double-edged sword to promote motor recovery

The inflammatory response following spinal cord injury is associated with increased tissue damage and impaired functional recovery. However, inflammation can also promote plasticity and the secretion of growth-promoting substances. Previously we have shown that inducing inflammation with a systemic injection of lipopolysaccharide in the chronic (8 weeks) stage of spinal cord injury enhances neuronal sprouting and the efficacy of rehabilitative training in rats. Here, we tested whether administration of lipopolysaccharide in female rats in the subacute (10 days) stage of spinal cord injury would have a similar effect. Since the lesioned environment is already in a pro-inflammatory state at this earlier time after injury, we hypothesized that triggering a second immune response may not be beneficial for recovery. Contrary to our hypothesis, we found that eliciting an inflammatory response 10 days after spinal cord injury enhanced the recovery of the ipsilesional forelimb in rehabilitative training. Compared to rats that received rehabilitative training without treatment, rats that received systemic lipopolysaccharide showed restored motor function without the use of compensatory strategies that translated beyond the trained task. Furthermore, lipopolysaccharide treatment paradoxically promoted the resolution of chronic neuroinflammation around the lesion site. Unfortunately, re-triggering a systemic immune response after spinal cord injury also resulted in a long-term increase in anxiety-like behaviour.

Forkhead box protein O1 (FoxO1) /SERPINB1 ameliorates ROS production in diabetic nephropathy

With the increasing prevalence of diabetes in recent years, diabetic nephropathy (DN) has become a severe disease that greatly threatens human health. DN not only is a common complication of diabetes, but also takes an important place in kidney disease. To this end, the present study was designed to explore the effects of Forkhead box protein O1 (FoxO1) on reactive oxygen species (ROS) production in DN mice. DN mice were treated with recombinant protein of FoxO1. Afterward, inflammation ELISA kits were used to measure the levels of TNF-α, IL-1β, IL-6, and IL-18. The levels of MDA, SOD, GSH, and GSH-PX were measured using kits according to the manufacturer's instructions. In addition, the production of ROS was assessed. Interestingly, the expression of FoxO1 was down-regulated in DN mice. The treatment of FoxO1 recombinant protein ameliorated MDA levels, increased the levels of SOD, GSH, and GSH-PX, and induced both mRNA and protein expression of hepatic serine protease inhibitor B1 (serpinB1) in ND mice. Similarly, FoxO1 reduced MDA levels and ROS production, increased the levels of SOD, GSH, and GSH-PXs, and induced the mRNA and protein expression of serpinB1 in in vitro model of DN. The inhibition of serpinB1 attenuated the effects of FoxO1 on ROS production-induced oxidative stress in in vitro model of DN. Overall, FoxO1/SERPINB1 ameliorated ROS production-induced oxidative stress in DN.

Delayed microglial depletion after spinal cord injury reduces chronic inflammation and neurodegeneration in the brain and improves neurological recovery in male mice

Neuropsychological deficits, including impairments in learning and memory, occur after spinal cord injury (SCI). In experimental SCI models, we and others have reported that such changes reflect sustained microglia activation in the brain that is associated with progressive neurodegeneration. In the present study, we examined the effect of pharmacological depletion of microglia on posttraumatic cognition, depressive-like behavior, and brain pathology after SCI in mice.

Methods: Young adult male C57BL/6 mice were subjected to moderate/severe thoracic spinal cord contusion. Microglial depletion was induced with the colony-stimulating factor 1 receptor (CSF1R) antagonist PLX5622 administered starting either 3 weeks before injury or one day post-injury and continuing through 6 weeks after SCI. Neuroinflammation in the injured spinal cord and brain was assessed using flow cytometry and NanoString technology. Neurological function was evaluated using a battery of neurobehavioral tests including motor function, cognition, and depression. Lesion volume and neuronal counts were quantified by unbiased stereology.

Results: Flow cytometry analysis demonstrated that PLX5622 pre-treatment significantly reduced the number of microglia, as well as infiltrating monocytes and neutrophils, and decreased reactive oxygen species production in these cells from injured spinal cord at 2-days post-injury. Post-injury PLX5622 treatment reduced both CD45^int microglia and CD45^hi myeloid counts at 7-days. Following six weeks of PLX5622 treatment, there were substantial changes in the spinal cord and brain transcriptomes, including those involved in neuroinflammation. These alterations were associated with improved neuronal survival in the brain and neurological recovery.

Conclusion: These findings indicate that pharmacological microglia-deletion reduces neuroinflammation in the injured spinal cord and brain, improving recovery of cognition, depressive-like behavior, and motor function.

Dementia, Depression, and Associated Brain Inflammatory Mechanisms after Spinal Cord Injury

Evaluation of the chronic effects of spinal cord injury (SCI) has long focused on sensorimotor deficits, neuropathic pain, bladder/bowel dysfunction, loss of sexual function, and emotional distress. Although not well appreciated clinically, SCI can cause cognitive impairment including deficits in learning and memory, executive function, attention, and processing speed; it also commonly leads to depression. Recent large-scale longitudinal population-based studies indicate that patients with isolated SCI (without concurrent brain injury) are at a high risk of dementia associated with substantial cognitive impairments. Yet, little basic research has addressed potential mechanisms for cognitive impairment and depression after injury. In addition to contributing to disability in their own right, these changes can adversely affect rehabilitation and recovery and reduce quality of life. Here, we review clinical and experimental work on the complex and varied responses in the brain following SCI. We also discuss potential mechanisms responsible for these less well-examined, important SCI consequences. In addition, we outline the existing and developing therapeutic options aimed at reducing SCI-induced brain neuroinflammation and post-injury cognitive and emotional impairments.

Curcumin and neurological diseases

Objectives: The beneficial effects of many substances have been discovered because of regular dietary consumption. This is also the case with curcumin, whose effects have been known for more than 4,000 years in Eastern countries such as China and India. A curcumin-rich diet has been known to counteract many human diseases, including cancer and diabetes, and has been shown to reduce inflammation. The effect of a curcumin treatment for neurological diseases, such as spinal muscular atrophy; Alzheimer's disease; Parkinson's disease; amyotrophic lateral sclerosis; multiple sclerosis; and others, has only recently been brought to the attention of researchers and the wider population.Methods: In this paper, we summarise the studies on this natural product, from its isolation two centuries ago to its characterisation a century later.Results: We describe its role in the treatment of neurological diseases, including its cellular and common molecular mechanisms, and we report on the clinical trials of curcumin with healthy people and patients.Discussion: Commenting on the different approaches adopted by the efforts made to increase its bioavailability.

A double-hit of stress and low-grade inflammation on functional brain network mediates posttraumatic stress symptoms

Growing evidence indicates a reciprocal relationship between low-grade systemic inflammation and stress exposure towards increased vulnerability to neuropsychiatric disorders, including posttraumatic stress disorder (PTSD). However, the neural correlates of this reciprocity and their influence on the subsequent development of PTSD are largely unknown. Here we investigated alterations in functional connectivity among brain networks related to low-grade inflammation and stress exposure using two large independent data sets. Functional couplings among the higher-order cognitive network system including the salience, default mode, and central executive networks were reduced in association with low-grade inflammation and stress exposure. This reduced functional coupling may also be related to subsequent posttraumatic stress symptom severity. The current findings propose functional couplings among the higher-order cognitive network system as neural correlates of low-grade inflammation and stress exposure, and suggest that low-grade inflammation, alongside with stress, may render individuals more vulnerable to PTSD.

Changes in nutrient intake and inflammation following an anti-inflammatory diet in spinal cord injury

Objective: The objective of the current study was to describe the observed changes in nutrient intakes following a 3-month anti-inflammatory diet, and to explore potential relationships between the change in nutrients and the change in various inflammatory mediators.Design: A secondary analysis of a prior randomized controlled clinical trial.Setting: Individuals with SCI within the Niagara region.Participants: Twenty individuals with various levels and severities of SCI.Intervention: Three-month anti-inflammatory diet.Outcome Measures: The change in nutrient intake and corresponding changes to various inflammatory mediators.Results: The treatment group demonstrated a significant reduction in fat intake (P = 0.02), a significant increase in protein intake (P = 0.02), and no change in carbohydrates (P = 0.23) or energy intake (P = 0.10). The treatment group showed a significant increase in some nutrients with established anti-inflammatory properties including vitamins A, C, and E, and omega-3 fatty acids (P < 0.01). Significant reductions in proinflammatory nutrients were observed including trans fatty acids (P = 0.05), caffeine (P < 0.01), and sodium (P = 0.02). The treatment group also showed significant reductions in the proinflammatory mediators interferon-y (P = 0.01), interleukin-1β (P < 0.01), and interleukin-6 (P < 0.05). Further, several proinflammatory mediators were negatively correlated with anti-inflammatory nutrients, including vitamin A, carotenoids, omega-3 fatty acids, and zinc.Conclusion: This study provides evidence that dietary alterations are effective at reducing chronic inflammation in individuals with SCI and provides a preliminary assessment of the related nutrient changes.

Recent advances in nanotherapeutic strategies for spinal cord injury repair

Spinal cord injury (SCI) is a devastating and complicated condition with no cure available. The initial mechanical trauma is followed by a secondary injury characterized by inflammatory cell infiltration and inhibitory glial scar formation. Due to the limitations posed by the blood-spinal cord barrier, systemic delivery of therapeutics is challenging. Recent development of various nanoscale strategies provides exciting and promising new means of treating SCI by crossing the blood-spinal cord barrier and delivering therapeutics. As such, we discuss different nanomaterial fabrication methods and provide an overview of recent studies where nanomaterials were developed to modulate inflammatory signals, target inhibitory factors in the lesion, and promote axonal regeneration after SCI. We also review emerging areas of research such as optogenetics, immunotherapy and CRISPR-mediated genome editing where nanomaterials can provide synergistic effects in developing novel SCI therapy regimens, as well as current efforts and barriers to clinical translation of nanomaterials.

SCI and depression: Does inflammation commandeer the brain?

The incidence of depression is almost twice as high in the spinally injured population compared to the general population. While this incidence has long been attributed to the psychological, economic, and social burdens that accompany spinal cord injury (SCI), data from animal studies indicate that the biology of SCI may play an important role in the development of depression. Inflammation has been shown to impact stress response in rodents and humans, and inflammatory cytokines have been associated with depression for decades. The inflammation inherent to SCI may disrupt necessary mechanisms of mental homeostasis, such as serotonin production, dopamine production, and the hypothalamic pituitary adrenal axis. Additionally, gut dysbiosis that occurs after SCI can exacerbate inflammation and may cause further mood and behavior changes. These mediators combined may significantly contribute to the rise in depression seen after SCI. Currently, there are no therapies specific to depression after SCI. Elucidation of the molecular pathways that contribute to SCI-specific depression is crucial for the understanding of this disease and its potential treatments.

Spinal cord injury by clip-compression induces anxiety and depression-like behaviours in female rats: The role of the inflammatory response

Traumatic spinal cord injury (SCI) promotes long-term disability that affects mobility and functional independence. The spinal cord inflammatory response after the initial mechanical insult substantially impacts locomotor impairment and development of neuropsychiatric disorders, including anxiety and depression. However, these psychiatric events are scarcely investigated in females. This study investigated the anxiety/depression-like behaviours and inflammatory responses related to the production/release of pro- and anti-inflammatory cytokines in female adult Wistar rats submitted to severe clip-compression SCI. Data showed that SCI impaired the locomotor performance assessment by the BBB scale, but did not alter exploratory activity in open-field test. Animals' locomotor impairment was associated with anxious and depressive-like behaviours characterised by a decreased amount of time in the open arms of the elevated plus-maze test, and the motivational reduction of social interaction and anhedonia assessed by social exploration and sucrose preference tests. By contrast, SCI decreased the immobility time in the forced swimming test. Moreover, SCI caused a significant increase in local and systemic proinflammatory cytokines (TNF-α, INF-γ, IL-1β, and IL-6) and a reduction in the anti-inflammatory cytokine IL-10. Finally, there were significant negative correlations between depression-like behaviour, but not anxiety, and increased plasma concentrations of TNF-α, IL-1β, IL-6, and INF-γ. Additionally, the laminectomy procedure provoked the inflammatory response associated with reduced sucrose intake in Sham animals, although less expressively than in the SCI group. Collectively, these results indicate that SCI by clip-compression in female rats promotes a neuropsychiatric-like profile associated with an imbalance in the production/release of pro- and anti-inflammatory cytokines.

An analysis of plasma reveals proteins in the acute phase response pathway to be candidate diagnostic biomarkers for depression

Globally, depression is one of the most serious debilitating psychiatric mental disorders. In this study, we validated the expression levels of fibrinogen alpha (FGA), fibrinogen beta (FGB), fibrinogen gamma (FGG), Complement factor B (CFB) and serpin family D member 1(SERPIND1) in the acute phase response signaling pathway in plasma samples using enzyme-linked immunosorbent assay (ELISA).Then illuminate the roles of FGA, FGB, FGG, CFB, SERPIND1 in depression using microarray data. Gene expression dataset GSE98793 was downloaded from the Gene Expression Omnibus database. There were 128 whole blood samples included 64 patients with major depressed patients and 64 healthy controls. Differentially expressed genes (DEGs) were identified, and then protein-protein interaction (PPI) network was constructed to screen crucial genes associated with FGA, FGB, FGG, CFB and SERPIND1. Moreover, gene ontology (GO) biological processes analyses was performed. The ELISA data showed that the expression levels of FGA, FGB, FGG, CFB and SERPIND1 were up-regulated in depressed patients. The enriched GO terms were predominantly associated with the biological processes including more genes were inflammation related. The PPI network was found these five genes interacted with 11 genes. FGA, FGB, FGG, CFB and SERPIND1 may be important in the pathogenesis of depression.

Maintenance of diet participation in individuals with spinal cord injury: effect on mood and neuropathic pain

Study design

One-year follow-up of a randomized clinical trial.

Objectives

Examine voluntary dietary compliance 1 year following the cessation of the intervention and the persistence of accrued benefits related to neuropathic pain and mood.

Setting

Outpatient rehabilitation program within the Niagara region.

Methods

Five individuals (4 female, 1 male; age 50.6 ± 11.8 years) with chronic SCI (C5-L3; ISNCSCI: A-D; 7-40 years post injury) who had previously completed a 3-month anti-inflammatory diet were reassessed after 1 year for measures related to dietary compliance, CES-D scores of depression, and NPQ scores of neuropathic pain.

Results

There was a significant reduction in diet compliance at the 1-year follow-up in comparison to the end of the dietary intervention at 3 months (92.6% versus 43.0%, p < 0.01). CES-D scores showed a trend toward an increase from 3 months to follow-up (8.0 versus 21.4, p = .10) whereby follow-up CES-D scores were no longer statistically different from baseline (p = 0.74). Sensory NPQ scores showed no significant change from 3 months to follow-up (25.2 versus 29.1, p = 0.42) and remained significantly lower than baseline (p = 0.02). Affective NPQ scores were significantly increased from 3 months to follow-up (27.7 versus 40.1, p = 0.05). Sensitivity NPQ scores showed no significant change from 3 month to follow-up (28.2 versus 33.5, p = 0.34), but returned to a score that was statistically similar to baseline (p = 0.15).

Conclusions

These results emphasize the importance of continued compliance to a diet with anti-inflammatory properties for the purposes of maintaining benefits related to mood and neuropathic pain in individuals with SCI.

Sponsorship

This study was supported by the Ontario Neurotrauma Foundation.

Association between dietary inflammatory index and psychological profile in adults

BACKGROUND & AIMS

Limited data are available on the association of inflammatory potential of the diet and odds of psychological disorders. We investigated the association between adherence to a pro-inflammatory diet, as measured by Dietary Inflammatory Index (DII), and odds of psychological disorders.

METHODS

In this cross-sectional study, dietary intakes of 3363 Iranian adult participants were collected using a validated Dish-based 106-item Semi-quantitative Food Frequency Questionnaire (DS-FFQ). DII score was calculated based on participants' dietary intakes obtained from DS-FFQ. The Iranian validated version of Hospital Anxiety and Depression Scale (HADS) and General Health Questionnaire (GHQ) was used to assess psychological disorders. For depression and anxiety, scores of 8 or more on either subscale were considered as psychological disorders and scores of 0-7 were defined as "normal". In terms of psychological distress, the score of 4 or more was defined as psychological distress.

RESULTS

Overall, 28% (n = 943) of study participants had depression, 13.3% (n = 448) were affected by anxiety and 22.6% (n = 760) by psychological distress. After controlling for potential confounders, individuals in the highest quintile of DII score had higher scores of depression (6.56 ± 0.16 vs. 5.48 ± 0.16; P < 0.001), anxiety (3.85 ± 0.17 vs. 3.09 ± 0.17; P = 0.006), and psychological distress (2.42 ± 0.13 vs. 1.77 ± 0.13; P = 0.001), compared with those in the lowest quintile. Participants in the top quintile of DII score had greater odds of depression (OR: 1.84, 95% CI: 1.30-2.60), anxiety (OR: 1.69, 95% CI: 1.07-2.67), and psychological distress (OR: 1.72, 95% CI: 1.20-2.46) than those in the bottom quintile.

CONCLUSIONS

We found that adherence to a pro-inflammatory diet was positively associated with psychological disorders.

Barriers and facilitators to adhering to an anti-inflammatory diet for individuals with spinal cord injuries

The purpose of this study was to explore the barriers and facilitators of an anti-inflammatory diet in people with spinal cord injury. Six participants (age range of 23-68 years, three women and three men) who had previously completed an anti-inflammatory diet study were interviewed. Facilitators identified were family support, autonomy over meal choice, peer support, health benefits gained, and implementation of adherence strategies. The main barriers discussed were lack of motivation after study period ended, social events, diet expenses, and lack of knowledge about the diet. Several health benefits including reductions in pain, edema, and improvements in cognition and mobility were reported.

An Integrative Approach to Neuroinflammation in Psychiatric disorders and Neuropathic Pain

Neuroinflammation is a complex process involving both the peripheral circulation and the Central Nervous System (CNS) and is considered to underlie many CNS disorders including depression, anxiety, schizophrenia, and pain. Stressors including early-life adversity, psychosocial stress, and infection appear to prime microglia toward a pro-inflammatory phenotype. Subsequent inflammatory challenges then drive an exaggerated neuroinflammatory response involving the upregulation of pro-inflammatory mediators that is associated with CNS dysfunction. Several pharmacologic inhibitors of pro-inflammatory cytokines including TNF-α and IL-1β show good clinical efficacy in terms of ameliorating neuroinflammatory processes. Mind/body and plant-based interventions such as yoga, breathing exercises, meditation, and herbs/spices have also been demonstrated to reduce pro-inflammatory cytokines and have a positive impact on depression, anxiety, cognition, and pain. As the intricate connections between the immune system and the nervous system continue to be elucidated, successful therapies for reducing neuroinflammation will likely involve an integrated approach combining drug therapy with nonpharmacologic interventions.

The Influence of Chronic Inflammation on Peripheral Motor Nerve Conduction Following Spinal Cord Injury: A Randomized Clinical Trial

Objective: To examine the potential influence of chronic inflammation on peripheral motor nerve function in vivo following spinal cord injury (SCI). Methods: This study was part of a randomized, parallel-group, controlled clinical trial. The study included 20 participants with varying levels and severities of SCI randomized (3:2) to either a treatment group, consisting of a 12-week anti-inflammatory diet program, or control group. Outcome measures were assessed at baseline, 1 month, and 3 months and consisted of measures of motor nerve conduction velocity (NCV) and amplitude as well as markers of inflammation as assessed by various pro- and anti-inflammatory cytokines. Results: Despite a significant reduction in inflammation in the treatment group, 2-way repeated measures analysis of variance (ANOVA) showed no significant Group × Time interaction for motor NCV (p = .77) or M-wave amplitude (p = .61). Further, the change in motor NCV and M-wave amplitude were not shown to be associated with the change in inflammatory mediators as assessed via a backwards elimination multiple regression analysis. Conclusion: These results suggest that at physiologically relevant concentrations, inflammatory mediators may not have a substantial influence on peripheral motor nerve conduction in vivo following SCI. Future studies may still be warranted to examine the potential for central effects.

Neuropathic Pain After Spinal Cord Injury: Challenges and Research Perspectives

Neuropathic pain is a debilitating consequence of spinal cord injury (SCI) that remains difficult to treat because underlying mechanisms are not yet fully understood. In part, this is due to limitations of evaluating neuropathic pain in animal models in general, and SCI rodents in particular. Though pain in patients is primarily spontaneous, with relatively few patients experiencing evoked pains, animal models of SCI pain have primarily relied upon evoked withdrawals. Greater use of operant tasks for evaluation of the affective dimension of pain in rodents is needed, but these tests have their own limitations such that additional studies of the relationship between evoked withdrawals and operant outcomes are recommended. In preclinical SCI models, enhanced reflex withdrawal or pain responses can arise from pathological changes that occur at any point along the sensory neuraxis. Use of quantitative sensory testing for identification of optimal treatment approach may yield improved identification of treatment options and clinical trial design. Additionally, a better understanding of the differences between mechanisms contributing to at- versus below-level neuropathic pain and neuropathic pain versus spasticity may shed insights into novel treatment options. Finally, the role of patient characteristics such as age and sex in pathogenesis of neuropathic SCI pain remains to be addressed.

Sparstolonin B attenuates spinal cord injury‑induced inflammation in rats by modulating TLR4‑trafficking

The present study used a spinal cord injury (SCI) model to evaluate whether sparstolonin B was able to prevent SCI, and to investigate the underlying signaling mechanism. Sparstolonin B attenuated the SCI‑induced Batto, Beattie and Bresnahan score and water content in rats. Sparstolonin B attenuated the mRNA expression of proinflammatory cytokines interleukin (IL)‑18, IL‑6, IL‑1β, and IL‑23, decreased the levels of tumor necrosis factor‑α and interferon‑γ, and decreased caspase‑3 activity and apoptosis regulator Bax protein expression in SCI rats. Similarly, sparstolonin B inhibited monocyte chemoattractant protein‑1 mRNA levels, and Toll‑like receptor (TLR) 4, myeloid differentiation primary response protein MyD88 (MyD88) and nuclear factor (NF)‑κB protein levels in SCI rats. The present results suggested that sparstolonin B may attenuate SCI‑induced inflammation and apoptosis in rats by modulating the TLR4/MyD88/NF‑κB signaling pathway.

Inhibiting the kynurenine pathway in spinal cord injury: Multiple therapeutic potentials?

Chronic induction of the kynurenine pathway (KP) contributes to neuroinflammation by producing the excitotoxin quinolinic acid (QUIN). This has led to significant interest in the development of inhibitors of this pathway, particularly in the context of neurodegenerative disease. However, acute spinal cord injury (SCI) also results in deleterious increases in QUIN, as secondary inflammatory processes mediated largely by infiltrating macrophages, become predominant. QUIN mediates significant neurotoxicity primarily by excitotoxic stimulation of the N-methyl-D-aspartate receptor, but other mechanisms of QUIN toxicity are known. More recent focus has assessed the contribution that neuroinflammation and modulations in the KP make in mood and psychiatric disorders with recent studies linking inflammation and modulations in the KP, to impaired cognitive performance and depressed mood in SCI patients. We hypothesize that these findings suggest that in SCI, inhibition of QUIN production and other metabolites, may have multiple therapeutic modalities and further studies investigating this are warranted. However, for central nervous system-based conditions, achieving good blood-brain-barrier permeability continues to be a limitation of current KP inhibitors.

Oxysophoridine rescues spinal cord injury via anti‑inflammatory, anti‑oxidative stress and anti‑apoptosis effects

Oxysophoridine (OSR) is an alkaloid extracted from Sophora alopecuroides L and has various pharmacological activities. The present study aimed to investigate the protective effects and underlying mechanisms of OSR on spinal cord injury (SCI), a clinically common serious trauma, in a rat model. The results of the present study demonstrated that the anti‑inflammatory effect of OSR improved Basso, Beatie and Bresnahan Locomotor Rating Scale scores and reduced spinal cord tissue water contents in an SCI rat model. Inflammatory activation was measured by ELISA, and Prostaglandin E2 (PGE2), intercellular adhesion molecule‑1 (ICAM‑1), cyclooxygenase‑2 (COX‑2), nuclear factor‑κB (NF‑κB) and B‑cell lymphoma 2 (Bcl‑2)/Bcl‑2‑associated X (Bax) protein expression levels using western blotting. The results revealed that treatment with OSR reduced tumor necrosis factor‑α, interleukin (IL)‑1β, IL‑6, IL‑8 and malondialdehyde, and increased superoxide dismutase and glutathione peroxidase levels in the serum of an SCI rat model. OSR significantly reduced the protein expression of inflammation‑associated proteins PGE2, ICAM‑1, COX‑2, NF‑κB and Bcl‑2/Bax ratio in the spinal cord tissue of an SCI rat model. Furthermore, the results of the current study demonstrate that OSR ameliorates SCI via anti‑inflammatory, anti‑oxidative stress and anti‑apoptosis effects.

Rehabilitation Interventions to modify endocrine-metabolic disease risk in Individuals with chronic Spinal cord injury living in the Community (RIISC): A systematic review and scoping perspective

CONTEXT

Endocrine-metabolic disease (EMD) risk following spinal cord injury (SCI) is associated with significant multi-morbidity (i.e. fracture, diabetes, heart disease), mortality, and economic burden. It is unclear to what extent rehabilitation interventions can modify EMD risk and improve health status in community-dwelling adults with chronic SCI.

OBJECTIVES

To characterize rehabilitation interventions and summarize evidence on their efficacy/effectiveness to modify precursors to EMD risk in community-dwelling adults with chronic SCI.

METHODS

Systematic searches of MEDLINE PubMed, EMBASE Ovid, CINAHL, CDSR, and PsychInfo were completed. All randomized, quasi-experimental, and prospective controlled trials comparing rehabilitation/therapeutic interventions with control/placebo interventions in adults with chronic SCI were eligible. Two authors independently selected studies and abstracted data. Mean differences of change from baseline were reported for EMD risk outcomes. The GRADE approach was used to rate the quality of evidence.

RESULTS

Of 489 articles identified, 16 articles (11 studies; n=396) were eligible for inclusion. No studies assessed the effects of rehabilitation interventions on incident fragility fractures, heart disease, and/or diabetes. Individual studies reported that exercise and/or nutrition interventions could improve anthropometric indices, body composition/adiposity, and biomarkers. However, there were also reports of non-statistically significant between-group differences.

CONCLUSIONS

There was very low-quality evidence that rehabilitation interventions can improve precursors to EMD risk in community-dwelling adults with chronic SCI. The small number of studies, imprecise estimates, and inconsistency across studies limited our ability to make conclusions. A high-quality longitudinal intervention trial is needed to inform community-based rehabilitation strategies for EMD risk after chronic SCI.

A narrative literature review of depression following traumatic brain injury: prevalence, impact, and management challenges

Depression is one of the most common conditions to emerge after traumatic brain injury (TBI), and despite its potentially serious consequences it remains undertreated. Treatment for post-traumatic depression (PTD) is complicated due to the multifactorial etiology of PTD, ranging from biological pathways to psychosocial adjustment. Identifying the unique, personalized factors contributing to the development of PTD could improve long-term treatment and management for individuals with TBI. The purpose of this narrative literature review was to summarize the prevalence and impact of PTD among those with moderate to severe TBI and to discuss current challenges in its management. Overall, PTD has an estimated point prevalence of 30%, with 50% of individuals with moderate to severe TBI experiencing an episode of PTD in the first year after injury alone. PTD has significant implications for health, leading to more hospitalizations and greater caregiver burden, for participation, reducing rates of return to work and affecting social relationships, and for quality of life. PTD may develop directly or indirectly as a result of biological changes after injury, most notably post-injury inflammation, or through psychological and psychosocial factors, including pre injury personal characteristics and post-injury adjustment to disability. Current evidence for effective treatments is limited, although the strongest evidence supports antidepressants and cognitive behavioral interventions. More personalized approaches to treatment and further research into unique therapy combinations may improve the management of PTD and improve the health, functioning, and quality of life for individuals with TBI.

Therapeutic effect of apatinib on overall survival is mediated by prolonged progression-free survival in advanced gastric cancer patients

Apatinib is reported to significantly improve the overall survival (OS) of patients with advanced gastric cancer who have previously failed second-line chemotherapy. However, it is not well understood whether apatinib acts by improving progression or by prolonging post-progression survival. Here, based on phase III clinical trial data, the mediating effect of apatinib on patient overall survival was systematically quantified, through progression-free survival (PFS), post-progression survival (PPS), and the disease control rate (DCR). PFS was the primary mediator of the association between apatinib treatment and OS, with an indirect-effect mean survival time ratio of 1.63 (95%CI 1.35-1.97), which mediated 93.5% of the treatment effect. The DCR was also a significant mediator among secondary efficacy endpoints, and had an indirect-effect mean survival time ratio of 1.47 (95%CI 1.20-1.79, 50.9% mediated). Both primary and other targets of the DCR had similar results. The results indicated that apatinib treatment prolongs progression-free survival rather than post-progression survival, and in turn, leads to improved overall survival. Additionally, our study highlights the value of mediation analysis in clinical trials in providing additional information to build upon traditional primary analysis.

Inflammatory Stress Effects on Health and Function After Spinal Cord Injury

Background: Injury to the spinal cord produces immediate, adaptive inflammatory responses that can exacerbate the initial injury and lead to secondary damage. Thus far, researchers and clinicians have focused on modulating acute inflammation to preserve sensorimotor function. However, this singular approach risks overlooking how chronic inflammation negatively impacts the broader health of persons with a spinal cord injury (SCI). Objective: The aim of this monograph was to discuss interrelated processes causing persistent inflammatory stress after SCI, along with associated health risks. We review archetypal factors that contribute to a chronic inflammatory state, including response to injury, acute infection, and autonomic dysreflexia. Secondary complications producing and exacerbating inflammation are also discussed, including pain, depression, obesity, and injury to the integumentary and skeletal systems. Finally, we discuss the role of bacteria and the gut microbiome in this process and then conclude with a discussion on how a pro-inflammatory phenotype promotes an elevated risk for cardiovascular disease after injury. Conclusions: Effectively managing chronic inflammation should be a high priority for clinicians and researchers who seek to improve the health and life quality of persons with SCI. Chronic inflammation worsens secondary medical complications and amplifies the risk for cardiometabolic disorders after injury, directly impacting both the quality of life and mortality risk after SCI. Inflammation can worsen pain and depression and even hinder neurological recovery. It is, therefore, imperative that countermeasures to chronic inflammation are routinely considered from the point of initial injury and proceeding throughout the lifespan of the individual with SCI.

Clearing the fog: a review of the effects of dietary omega-3 fatty acids and added sugars on chemotherapy-induced cognitive deficits

Cancer treatments such as chemotherapy have been an important part of extending survival in women diagnosed with breast cancer. However, chemotherapy can cause potentially toxic side effects in the brain that impair memory, verbal fluency, and processing speed in up to 30% of women treated. Women report that post-chemotherapy cognitive deficits negatively impact quality of life and may last up to ten years after treatment. Mechanisms underlying these cognitive impairments are not fully understood, but emerging evidence suggests that chemotherapy induces structural changes in the brain, produces neuroinflammation, and reduces adult hippocampal neurogenesis. Dietary approaches that modify inflammation and neurogenesis are promising strategies for reducing chemotherapy-induced cognitive deficits in breast cancer survivors. In this review, we describe the cognitive and neuronal side effects associated with commonly used chemotherapy treatments for breast cancer, and we focus on the often opposing actions of omega-3 fatty acids and added sugars on cognitive function, neuroinflammation, and adult hippocampal neurogenesis. Omega-3 fatty acids administered concurrently with doxorubicin chemotherapy have been shown to prevent depressive-like behaviors and reduce neuroinflammation, oxidative stress, and neural apoptosis in rodent models. In contrast, diets high in added sugars may interact with n-3 FAs to diminish their anti-inflammatory activity or act independently to increase neuroinflammation, reduce adult hippocampal neurogenesis, and promote cognitive deficits. We propose that a diet rich in long-chain, marine-derived omega-3 fatty acids and low in added sugars may be an ideal pattern for preventing or alleviating neuroinflammation and oxidative stress, thereby protecting neurons from the toxic effects of chemotherapy. Research testing this hypothesis could lead to the identification of modifiable dietary choices to reduce the long-term impact of chemotherapy on the cognitive functions that are important to quality of life in breast cancer survivors.

Multiple organ dysfunction and systemic inflammation after spinal cord injury: a complex relationship

Spinal cord injury (SCI) is a devastating event that results in significant physical disabilities for affected individuals. Apart from local injury within the spinal cord, SCI patients develop a variety of complications characterized by multiple organ dysfunction or failure. These disorders, such as neurogenic pain, depression, lung injury, cardiovascular disease, liver damage, kidney dysfunction, urinary tract infection, and increased susceptibility to pathogen infection, are common in injured patients, hinder functional recovery, and can even be life threatening. Multiple lines of evidence point to pathological connections emanating from the injured spinal cord, post-injury systemic inflammation, and immune suppression as important multifactorial mechanisms underlying post-SCI complications. SCI triggers systemic inflammatory responses marked by increased circulation of immune cells and pro-inflammatory mediators, which result in the infiltration of inflammatory cells into secondary organs and persistence of an inflammatory microenvironment that contributes to organ dysfunction. SCI also induces immune deficiency through immune organ dysfunction, resulting in impaired responsiveness to pathogen infection. In this review, we summarize current evidence demonstrating the relevance of inflammatory conditions and immune suppression in several complications frequently seen following SCI. In addition, we highlight the potential pathways by which inflammatory and immune cues contribute to multiple organ failure and dysfunction and discuss current anti-inflammatory approaches used to alleviate post-SCI complications. A comprehensive review of this literature may provide new insights into therapeutic strategies against complications after SCI by targeting systemic inflammation.

Polyphenols in dementia: From molecular basis to clinical trials

Dementia is common in the elderly, but there are currently no effective therapies available to prevent or treat this syndrome. In the last decade, polyphenols (particularly curcumin, resveratrol and tea catechins) have been under very close scrutiny as potential therapeutic agents for neurodegenerative diseases, diabetes, inflammatory diseases and aging. Data were collected from Web of Science (ISI Web of Knowledge), Pubmed and Medline (from 2000 to 2015), by searching for the keywords "dementia" AND "curcumin", "resveratrol", "EGCG", "tea catechins". The same keywords were used to investigate the current state of clinical trials recorded in the NIH clinicaltrials.gov registry. Starting from the intrinsic properties of the compounds, we explain their specific action in patients with AD and the most common types of dementia. The pharmacological actions of curcumin, resveratrol and tea catechins have mainly been attributed to their antioxidant activity, interaction with cell signaling pathways, anti-inflammatory effect, chelation of metal ions, and neuroprotection. Evidence from in vitro and in vivo studies on polyphenols have demonstrated that they may play an integral role in preventing and treating diseases associated with neurodegeneration. Furthermore, we critically analyze the clinical trials that we found, which investigate the real pharmacological actions and the possible side effects of these compounds. This review highlights the potential role of polyphenols in the prevention/treatment of dementia and describes the current limitations of research in this field.

Do measures of depressive symptoms function differently in people with spinal cord injury versus primary care patients: the CES-D, PHQ-9, and PROMIS®-D

PURPOSE

To evaluate whether items of three measures of depressive symptoms function differently in persons with spinal cord injury (SCI) than in persons from a primary care sample.

METHODS

This study was a retrospective analysis of responses to the Patient Health Questionnaire depression scale, the Center for Epidemiological Studies Depression scale, and the National Institutes of Health Patient-Reported Outcomes Measurement Information System (PROMIS^®) version 1.0 eight-item depression short form 8b (PROMIS-D). The presence of differential item function (DIF) was evaluated using ordinal logistic regression.

RESULTS

No items of any of the three target measures were flagged for DIF based on standard criteria. In a follow-up sensitivity analyses, the criterion was changed to make the analysis more sensitive to potential DIF. Scores were corrected for DIF flagged under this criterion. Minimal differences were found between the original scores and those corrected for DIF under the sensitivity criterion.

CONCLUSIONS

The three depression screening measures evaluated in this study did not perform differently in samples of individuals with SCI compared to general and community samples. Transdiagnostic symptoms did not appear to spuriously inflate depression severity estimates when administered to people with SCI.

Targeting inflammation to influence cognitive function following spinal cord injury: a randomized clinical trial

STUDY DESIGN

This study was a randomized, parallel-group, controlled clinical trial.

OBJECTIVES

The purpose of this study was to examine the efficacy of targeting inflammation as a means of improving cognitive function in individuals with spinal cord injury.

SETTING

Participants were recruited from the Niagara region of Ontario Canada and all testing occurred on-site at Brock University.

METHODS

Indices of memory and verbal learning were assessed by means of the California Verbal Learning Test (CVLT). Inflammation and concentrations of neuroactive compounds related to the kynurenine pathway were assessed via a number of pro- and anti-inflammatory cytokines, as well as tryptophan, kynurenine and several large neutral amino acids. All assessments were performed at baseline as well as at 1 month and 3 months during a 3-month intervention by means of an anti-inflammatory diet.

RESULTS

Despite a reduction in inflammation, all measures of the CVLT, including list A, trial 1 (P=0.48), learning slope (P=0.46), long delay free recall (P=0.83), intrusions (P=0.61) and repetitions (P=0.07), showed no significant group × time interaction.

CONCLUSION

It may be possible that the reduction in inflammation achieved in the current study was insufficient to induce substantial changes in indices of verbal learning and memory. Alternatively, as these participants likely underwent years of previous chronic inflammation, the underlying hippocampal damage may have negated potential improvements induced by acute reductions in inflammation.

Targeting inflammation as a treatment modality for neuropathic pain in spinal cord injury: a randomized clinical trial

Background

The purpose of the present study was to examine the effectiveness of an anti-inflammatory intervention as a treatment for neuropathic pain following spinal cord injury (SCI).

Methods

This randomized, parallel-group, controlled clinical trial (NCT02099890) examined 20 participants with varying levels and severities of SCI, randomized (3:2) to either a 12-week anti-inflammatory diet, or control group. Outcome measures consisted of self-determined indices of pain as assessed using the neuropathic pain questionnaire (NPQ) and markers of inflammation as assessed by various pro- and anti-inflammatory cytokines, as well as the eicosanoids PGE2 and LTB4.

Results

A significant group × time interaction was found for sensory pain scores (p < 0.01). A Mann-Whitney test revealed that the change scores (3-month baseline) were significantly different between groups for IFN-y (U = 13.0, p = 0.01), IL-1β (U = 14.0, p = 0.01), and IL-2 (U = 12.0, p = 0.01). A Friedman test revealed the treatment group had a significant reduction in IFN-y (x² = 8.67, p = 0.01), IL-1β (x² = 17.78, p < 0.01), IL-6 (x² = 6.17, p < 0.05), while the control group showed no significant change in any inflammatory mediator. A stepwise backward elimination multiple regression analysis showed that the change in sensory neuropathic pain was a function of the change in the proinflammatory cytokines IL-2 and IFN-y, as well as the eicosanoid PGE2 (R = 0.689, R² = 0.474).

Conclusions

Overall, the results of the study demonstrate the efficacy of targeting inflammation as a means of treating neuropathic pain in SCI, with a potential mechanism relating to the reduction in proinflammatory cytokines and PGE2.

Trial registration

ClinicalTrials.gov, NCT02099890

Electronic supplementary material

The online version of this article (doi:10.1186/s12974-016-0625-4) contains supplementary material, which is available to authorized users.

Neuroteratology and Animal Modeling of Brain Disorders

Over the past 60 years, a large number of selective neurotoxins were discovered and developed, making it possible to animal-model a broad range of human neuropsychiatric and neurodevelopmental disorders. In this paper, we highlight those neurotoxins that are most commonly used as neuroteratologic agents, to either produce lifelong destruction of neurons of a particular phenotype, or a group of neurons linked by a specific class of transporter proteins (i.e., dopamine transporter) or body of receptors for a specific neurotransmitter (i.e., NMDA class of glutamate receptors). Actions of a range of neurotoxins are described: 6-hydroxydopamine (6-OHDA), 6-hydroxydopa, DSP-4, MPTP, methamphetamine, IgG-saporin, domoate, NMDA receptor antagonists, and valproate. Their neuroteratologic features are outlined, as well as those of nerve growth factor, epidermal growth factor, and that of stress. The value of each of these neurotoxins in animal modeling of human neurologic, neurodegenerative, and neuropsychiatric disorders is discussed in terms of the respective value as well as limitations of the derived animal model. Neuroteratologic agents have proven to be of immense importance for understanding how associated neural systems in human neural disorders may be better targeted by new therapeutic agents.