Brain Phospholipid Precursors Administered Post-Injury Reduce Tissue Damage and Improve Neurological Outcome in Experimental Traumatic Brain Injury

Glycerophospholipid dysregulation after traumatic brain injury

Brain tissue is highly enriched in lipids, the majority of which are glycerophospholipids. Glycerophospholipids are the major constituents of cellular membranes and play an important role in maintaining integrity and function of cellular and subcellular structures. Any changes in glycerophospholipid homeostasis can adversely affect brain functions. Traumatic brain injury (TBI), an acquired injury caused by the impact of external forces to the brain, triggers activation of secondary biochemical events that include perturbation of lipid homeostasis. Several studies have demonstrated glycerophospholipid dysregulation in the brain and circulation after TBI. This includes spatial and temporal changes in abundance and distribution of glycerophospholipids in the injured brain. This is at least in part mediated by TBI-induced oxidative stress and by activation of lipid metabolism pathways involved in tissue repairing. In this review, we discuss current advances in understanding of the mechanisms and implications of glycerophospholipid dysregulation following TBI.

The cellular senescence response and neuroinflammation in juvenile mice following controlled cortical impact and repetitive mild traumatic brain injury

Traumatic brain injury (TBI) is a leading cause of disability and increases the risk of developing neurodegenerative diseases. The mechanisms linking TBI to neurodegeneration remain to be defined. It has been proposed that the induction of cellular senescence after injury could amplify neuroinflammation and induce long-term tissue changes. The induction of a senescence response post-injury in the immature brain has yet to be characterised. We carried out two types of brain injury in juvenile CD1 mice: invasive TBI using controlled cortical impact (CCI) and repetitive mild TBI (rmTBI) using weight drop injury. The analysis of senescence-related signals showed an increase in γH2AX-53BP1 nuclear foci, p53, p19ARF, and p16INK4a expression in the CCI group, 5 days post-injury (dpi). At 35 days, the difference was no longer statistically significant. Gene expression showed the activation of different senescence pathways in the ipsilateral and contralateral hemispheres in the injured mice. CCI-injured mice showed a neuroinflammatory early phase after injury (increased Iba1 and GFAP expression), which persisted for GFAP. After CCI, there was an increase at 5 days in p16INK4, whereas in rmTBI, a significant increase was seen at 35 dpi. Both injuries caused a decrease in p21 at 35 dpi. In rmTBI, other markers showed no significant change. The PCR array data predicted the activation of pathways connected to senescence after rmTBI. These results indicate the induction of a complex cellular senescence and glial reaction in the immature mouse brain, with clear differences between an invasive brain injury and a repetitive mild injury.

Lysophospholipids Are Associated With Outcomes in Hospitalized Patients With Mild Traumatic Brain Injury

Mild traumatic brain injury (mTBI) accounts for 70-90% of all TBI cases. Lipid metabolites have important roles in plasma membrane biogenesis, function, and cell signaling. As TBI can compromise plasma membrane integrity and alter brain cell function, we sought to identify circulating phospholipid alterations after mTBI, and determine if these changes were associated with clinical outcomes. Patients with mTBI (Glasgow Coma Score [GCS] ≥13 and loss of consciousness <30 min) were recruited. A total of 84 mTBI subjects were enrolled after admission to a level I trauma center, with the majority having evidence of traumatic intracranial hemorrhage on brain computed tomography (CT). Plasma samples were collected within 24 h of injury with 32 mTBI subjects returning at 3 months after injury for a second plasma sample to be collected. Thirty-five healthy volunteers were enrolled as controls and had a one-time blood draw. Lipid metabolomics was performed on plasma samples from each subject. Fold change of selected lipid metabolites was determined. Multivariable regression models were created to test associations between lipid metabolites and discharge and 6-month Glasgow Outcomes Scale-Extended (GOSE) outcomes (dichotomized between "good" [GOSE ≥7] and "bad" [GOSE ≤6] functional outcomes). Plasma levels of 31 lipid metabolites were significantly associated with discharge GOSE using univariate models; three of these metabolites were significantly increased, while 14 were significantly decreased in subjects with good outcomes compared with subjects with poor outcomes. In multivariable logistic regression models, higher circulating levels of the lysophospholipids (LPL) 1-linoleoyl-glycerophosphocholine (GPC) (18:2), 1-linoleoyl-GPE (18:2), and 1-linolenoyl-GPC (18:3) were associated with both good discharge GOSE (odds ratio [OR] 12.2 [95% CI 3.35, 58.3], p = 5.23 × 10-4; OR 9.43 [95% CI 2.87, 39.6], p = 7.26 × 10-4; and OR 5.26 [95% CI 1.99, 16.7], p = 2.04 × 10-3, respectively) and 6-month (OR 4.67 [95% CI 1.49, 17.7], p = 0.013; OR 2.93 [95% CI 1.11, 8.87], p = 0.039; and OR 2.57 [95% CI 1.08, 7.11], p = 0.046, respectively). Compared with healthy volunteers, circulating levels of these three LPLs were decreased early after injury and had normalized by 3 months after injury. Logistic regression models to predict functional outcomes were created by adding each of the described three LPLs to a baseline model that included age and sex. Including 1-linoleoyl-GPC (18:2) (8.20% improvement, p = 0.009), 1-linoleoyl-GPE (18:2) (8.85% improvement, p = 0.021), or 1-linolenoyl-GPC (18:3) (7.68% improvement, p = 0.012), significantly improved the area under the curve (AUC) for predicting discharge outcomes compared with the baseline model. Models including 1-linoleoyl-GPC (18:2) significantly improved AUC for predicting 6-month outcomes (9.35% improvement, p = 0.034). Models including principal components derived from 25 LPLs significantly improved AUC for prediction of 6-month outcomes (16.0% improvement, p = 0.020). Our results demonstrate that higher plasma levels of LPLs (1-linoleoyl-GPC, 1-linoleoyl-GPE, and 1-linolenoyl-GPC) after mTBI are associated with better functional outcomes at discharge and 6 months after injury. This class of phospholipids may represent a potential therapeutic target.

A Potential Role Exists for Nutritional Interventions in the Chronic Phase of Mild Traumatic Brain Injury, Concussion and Sports-Related Concussion: A Systematic Review

Mild traumatic brain injury (mTBI) represents a significant burden for individuals, economies, and healthcare systems worldwide. Recovery protocols focus on medication and physiotherapy-based interventions. Animal studies have shown that antioxidants, branched-chain amino acids and omega-3 fatty acids may improve neurophysiological outcomes after TBI. However, there appears to be a paucity of nutritional interventions in humans with chronic (≥1 month) symptomology post-mTBI. This systematic literature review aimed to consolidate evidence for nutrition and dietary-related interventions in humans with chronic mTBI. The review was registered with the International Prospective Register of Systematic Reviews (PROSPERO; CRD42021277780) and conducted following the Preferred Reporting for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Three reviewers searched five databases (PubMed/MEDLINE, Web of Science, SPORTDiscus, CINAHL Complete and Cochrane), which yielded 6164 studies. Nine studies met the inclusion criteria. The main finding was the lack of interventions conducted to date, and a quality assessment of the included studies was found to be fair to good. Due to heterogeneity, a meta-analysis was not feasible. The six nutrition areas identified (omega-3 fatty acids, melatonin, Enzogenol®, MLC901, ketogenic diet and phytocannabinoids) were safe and well-tolerated. It was found that these nutritional interventions may improve cognitive failures, sleep disturbances, anxiety, physical disability, systolic blood pressure volume and sport concussion assessment tool scores following mTBI. Potential areas of improvement identified for future studies included blinding, reporting compliance, and controlling for confounders. In conclusion, further research of higher quality is needed to investigate the role of nutrition in recovery from mTBI to reduce the burden of chronic outcomes following mTBI.

CatWalk XT gait parameters: a review of reported parameters in pre-clinical studies of multiple central nervous system and peripheral nervous system disease models

Automated gait assessment tests are used in studies of disorders characterized by gait impairment. CatWalk XT is one of the first commercially available automated systems for analyzing the gait of rodents and is currently the most used system in peer-reviewed publications. This automated gait analysis system can generate a large number of gait parameters. However, this creates a new challenge in selecting relevant parameters that describe the changes within a particular disease model. Here, for the first time, we performed a multi-disorder review on published CatWalk XT data. We identify commonly reported CatWalk XT gait parameters derived from 91 peer-reviewed experimental studies in mice, covering six disorders of the central nervous system (CNS) and peripheral nervous system (PNS). The disorders modeled in mice were traumatic brain injury (TBI), stroke, sciatic nerve injury (SNI), spinal cord injury (SCI), Parkinson's disease (PD), and ataxia. Our review consisted of parameter selection, clustering, categorization, statistical evaluation, and data visualization. It suggests that certain gait parameters serve as potential indicators of gait dysfunction across multiple disease models, while others are specific to particular models. The findings also suggest that the more site-specific the injury is, the fewer parameters are reported to characterize its gait abnormalities. This study strives to present a clearly organized picture of gait parameters used in each one of the different mouse models, potentially helping novel CatWalk XT users to apply this information to similar or related mouse models they are working on.

High-Throughput Analysis of Astrocyte Cultures Shows Prevention of Reactive Astrogliosis by the Multi-Nutrient Combination Fortasyn Connect

Astrocytes are specialized glial cells that tile the central nervous system (CNS) and perform numerous essential functions. Astrocytes react to various forms of CNS insults by altering their morphology and molecular profile, through a process known as reactive astrogliosis. Accordingly, astrocyte reactivity is apparent in many neurodegenerative diseases, among which one is Alzheimer’s disease (AD). Recent clinical trials on early-stage AD have demonstrated that Fortasyn Connect (FC), a multi-nutrient combination providing specific precursors and cofactors for phospholipid synthesis, helps to maintain neuronal functional connectivity and cognitive performance of patients. Several studies have shown that FC may act through its effects on neuronal survival and synaptogenesis, leading to reduced astrocyte reactivity, but whether FC can directly counteract astrocyte reactivity remains to be elucidated. Hence, we developed an in vitro model of reactive astrogliosis using the pro-inflammatory cytokines TNF-α and IFN-γ together with an automated high-throughput assay (AstroScan) to quantify molecular and morphological changes that accompany reactive astrogliosis. Next, we showed that FC is potent in preventing cytokine-induced reactive astrogliosis, a finding that might be of high relevance to understand the beneficial effects of FC-based interventions in the context of neurodegenerative diseases.

Nutritional Supplementation Reduces Lesion Size and Neuroinflammation in a Sex-Dependent Manner in a Mouse Model of Perinatal Hypoxic-Ischemic Brain Injury

Perinatal hypoxia-ischemia (HI) is a major cause of neonatal brain injury, leading to long-term neurological impairments. Medical nutrition can be rapidly implemented in the clinic, making it a viable intervention to improve neurodevelopment after injury. The omega-3 (n-3) fatty acids docosahexaenoic acid (DHA, 22:6n-3) and eicosapentaenoic acid (EPA, 20:5n-3), uridine monophosphate (UMP) and choline have previously been shown in rodents to synergistically enhance brain phospholipids, synaptic components and cognitive performance. The objective of this study was to test the efficacy of an experimental diet containing DHA, EPA, UMP, choline, iodide, zinc, and vitamin B12 in a mouse model of perinatal HI. Male and female C57Bl/6 mice received the experimental diet or an isocaloric control diet from birth. Hypoxic ischemic encephalopathy was induced on postnatal day 9 by ligation of the right common carotid artery and systemic hypoxia. To assess the effects of the experimental diet on long-term motor and cognitive outcome, mice were subjected to a behavioral test battery. Lesion size, neuroinflammation, brain fatty acids and phospholipids were analyzed at 15 weeks after HI. The experimental diet reduced lesion size and neuroinflammation specifically in males. In both sexes, brain n-3 fatty acids were increased after receiving the experimental diet. The experimental diet also improved novel object recognition, but no significant effects on motor performance were observed. Current data indicates that early life nutritional supplementation with a combination of DHA, EPA, UMP, choline, iodide, zinc, and vitamin B12 may provide neuroprotection after perinatal HI.

Traumatic Brain Injury: Mechanisms of Glial Response

Traumatic brain injury (TBI) is a heterogeneous disorder that involves brain damage due to external forces. TBI is the main factor of death and morbidity in young males with a high incidence worldwide. TBI causes central nervous system (CNS) damage under a variety of mechanisms, including synaptic dysfunction, protein aggregation, mitochondrial dysfunction, oxidative stress, and neuroinflammation. Glial cells comprise most cells in CNS, which are mediators in the brain’s response to TBI. In the CNS are present astrocytes, microglia, oligodendrocytes, and polydendrocytes (NG2 cells). Astrocytes play critical roles in brain’s ion and water homeostasis, energy metabolism, blood-brain barrier, and immune response. In response to TBI, astrocytes change their morphology and protein expression. Microglia are the primary immune cells in the CNS with phagocytic activity. After TBI, microglia also change their morphology and release both pro and anti-inflammatory mediators. Oligodendrocytes are the myelin producers of the CNS, promoting axonal support. TBI causes oligodendrocyte apoptosis, demyelination, and axonal transport disruption. There are also various interactions between these glial cells and neurons in response to TBI that contribute to the pathophysiology of TBI. In this review, we summarize several glial hallmarks relevant for understanding the brain injury and neuronal damage under TBI conditions.

Dynamics of Choline-Containing Phospholipids in Traumatic Brain Injury and Associated Comorbidities

The incidences of traumatic brain injuries (TBIs) are increasing globally because of expanding population and increased dependencies on motorized vehicles and machines. This has resulted in increased socio-economic burden on the healthcare system, as TBIs are often associated with mental and physical morbidities with lifelong dependencies, and have severely limited therapeutic options. There is an emerging need to identify the molecular mechanisms orchestrating these injuries to life-long neurodegenerative disease and a therapeutic strategy to counter them. This review highlights the dynamics and role of choline-containing phospholipids during TBIs and how they can be used to evaluate the severity of injuries and later targeted to mitigate neuro-degradation, based on clinical and preclinical studies. Choline-based phospholipids are involved in maintaining the structural integrity of the neuronal/glial cell membranes and are simultaneously the essential component of various biochemical pathways, such as cholinergic neuronal transmission in the brain. Choline or its metabolite levels increase during acute and chronic phases of TBI because of excitotoxicity, ischemia and oxidative stress; this can serve as useful biomarker to predict the severity and prognosis of TBIs. Moreover, the effect of choline-replenishing agents as a post-TBI management strategy has been reviewed in clinical and preclinical studies. Overall, this review determines the theranostic potential of choline phospholipids and provides new insights in the management of TBI.

The More, the Better: High-Dose Omega-3 Fatty Acids Improve Behavioural and Molecular Outcomes in Preclinical Models in Mild Brain Injury

PURPOSE OF REVIEW

Mild traumatic brain injury (mTBI) is a continuing healthcare concern worldwide contributing to significant cognitive and neurological impairment, consequently affecting activities of daily living. While mTBI recovery is becoming well studied, there are no interventions to reduce the known impairments of mTBI. Omega-3 fatty acids (N-3FA) are safe and beneficial for brain health; however, their potential effects in a pathophysiological environment such as that seen post-mTBI are unknown.

RECENT FINDINGS

Preclinical studies using rodent models are key to understanding molecular mechanisms underlying improvements post-injury. Studies to date have shown improved outcomes in rodent models following mTBI protocols, but these data have not been quantified using a systematic review and meta-analysis approach. Our systematic review assessed 291 studies identified from the literature. Of these studies, 18 studies met inclusion criteria. We conducted a meta-analysis examining the effect of high-dose n-3FA vs placebo on neurological, cognitive and molecular changes following mTBI. Quality of studies was rated as moderate to high quality, and while mostly compliant, some areas of risk of bias were identified. Results showed that preclinical doses of 10-370 mg/kg/day of n-3FA per day in rodents (equivalent to high clinical doses) resulted in improvements in neurological and cognitive performance (pooled effect sizes ranging between 1.52 and 3.55). Similarly, improvements in molecular and inflammatory markers were observed in treated rodents vs control (pooled effect sizes: 3.73-6.55). Overall, these findings highlight the potential for high-dose n-3FA for human clinical studies following mTBI.

Chemokine Receptors CC Chemokine Receptor 5 and C-X-C Motif Chemokine Receptor 4 Are New Therapeutic Targets for Brain Recovery after Traumatic Brain Injury

Recently, chemokine receptor CC chemokine receptor 5 (CCR5) was found to be a negative modulator of learning and memory. Its inhibition improved outcome after stroke and traumatic brain injury (TBI). To better understand its role after TBI and establish therapeutic strategies, we investigated the effect of reduced CCR5 signaling as a neuroprotective strategy and of the temporal changes of CCR5 expression after TBI in different brain cell types. To silence CCR5 expression, ccr5 short hairpin RNA (shRNA) or dsred shRNA (control) was injected into the cornu ammonis (CA) 1 and CA3 regions of the hippocampus 2 weeks before induction of closed-head injury in mice. Animals were then monitored for 32 days and euthanized at different time points to assess lesion area, inflammatory components of the glial response (immunohistochemistry; IHC), cytokine levels (enzyme-linked immunosorbent array), and extracellular signal-regulated kinase (ERK) phosphorylation (western blot). Fluorescence-activated cell sorting (FACS) analysis was performed to study post-injury temporal changes of CCR5 and C-X-C motif chemokine receptor 4 (CXCR4) expression in cortical and hippocampal cell populations (neurons, astrocytes, and microglia). Phosphorylation of the N-methyl-d-aspartate subunit 1 (NR1) subunit of N-methyl-d-aspartate (western blot) and cAMP-response-element-binding protein (CREB; IHC) were also assessed. The ccr5 shRNA mice displayed reduced lesion area, dynamic alterations in levels of inflammation-related CCR5 ligands and cytokines, and higher levels of phosphorylated ERK. The ccr5 shRNA also reduced astrocytosis in the lesioned and sublesioned cortex. FACS analysis revealed increased cortical CCR5 and CXCR4 expression in CD11b-positive cells, astrocytes, and neurons, which was most evident in cells expressing both receptors, at 3 and 11 days post-injury. The lowest levels of phosphorylated NR1 and phosphorylated CREB were found at day 3 post-injury, suggesting that this is the critical time point for therapeutic intervention.

A new ketogenic formulation improves functional outcome and reduces tissue loss following traumatic brain injury in adult mice

Rationale: Traumatic brain injury (TBI) leads to neurological impairment, with no satisfactory treatments available. Classical ketogenic diets (KD), which reduce reliance on carbohydrates and provide ketones as fuel, have neuroprotective potential, but their high fat content reduces compliance, and experimental evidence suggests they protect juvenile brain against TBI, but not adult brain, which would strongly limit their applicability in TBI. Methods: We designed a new-KD with a fat to carbohydrate plus protein ratio of 2:1, containing medium chain triglycerides (MCT), docosahexaenoic acid (DHA), low glycaemic index carbohydrates, fibres and the ketogenic amino acid leucine, and evaluated its neuroprotective potential in adult TBI. Adult male C57BL6 mice were injured by controlled cortical impact (CCI) and assessed for 70 days, during which they received a control diet or the new-KD. Results: The new-KD, that markedly increased plasma Beta-hydroxybutyrate (β-HB), significantly attenuated sensorimotor deficits and corrected spatial memory deficit. The lesion size, perilesional inflammation and oxidation were markedly reduced. Oligodendrocyte loss appeared to be significantly reduced. TBI activated the mTOR pathway and the new-KD enhanced this increase and increased histone acetylation and methylation. Conclusion: The behavioural improvement and tissue protection provide proof of principle that this new formulation has therapeutic potential in adult TBI.

Neural Markers of Vulnerability to Anxiety Outcomes after Traumatic Brain Injury

Anxiety outcomes after traumatic brain injury (TBI) are complex, and the underlying neural mechanisms are poorly understood. Here, we developed a multi-dimensional behavioral profiling approach to investigate anxiety-like outcomes in mice that takes into account individual variability. Departing from the tradition of comparing outcomes in TBI versus sham groups, we identified a subgroup within the TBI group that is vulnerable to anxiety dysfunction, and present increased exploration of the anxiogenic zone compared to sham controls or resilient injured animals, by applying dimensionality reduction, clustering, and post hoc validation to behavioral data obtained from multiple assays for anxiety at several post-injury time points. These vulnerable animals expressed distinct molecular profiles in the corticolimbic network, with downregulation in gamma-aminobutyric acid and glutamate and upregulation in neuropeptide Y markers. Indeed, among vulnerable animals, not resilient or sham controls, severity of anxiety-related outcomes correlated strongly with expression of molecular markers. Our results establish a foundational approach, with predictive power, for reliably identifying maladaptive anxiety outcomes after TBI and uncovering neural signatures of vulnerability to anxiety.

Nutritional interventions to improve neurophysiological impairments following traumatic brain injury: A systematic review

Traumatic brain injury (TBI) accounts for significant global health burden. Effects of TBI can become chronic even following mild injury. There is a need to develop effective therapies to attenuate the damaging effects of TBI and improve recovery outcomes. This literature review using a priori criteria (PROSPERO; CRD42018100623) summarized 43 studies between January 1998 and July 2019 that investigated nutritional interventions (NUT) delivered with the objective of altering neurophysiological (NP) outcomes following TBI. Risk of bias was assessed for included studies, and NP outcomes recorded. The systematic search resulted in 43 of 3,748 identified studies met inclusion criteria. No studies evaluated the effect of a NUT on NP outcomes of TBI in humans. Biomarkers of morphological changes and apoptosis, oxidative stress, and plasticity, neurogenesis, and neurotransmission were the most evaluated NP outcomes across the 43 studies that used 2,897 animals. The risk of bias was unclear in all reviewed studies due to poorly detailed methodology sections. Taking these limitations into account, anti-oxidants, branched chain amino acids, and ω-3 polyunsaturated fatty acids have shown the most promising pre-clinical results for altering NP outcomes following TBI. Refinement of pre-clinical methodologies used to evaluate effects of interventions on secondary damage of TBI would improve the likelihood of translation to clinical populations.

Metabolomics Deciphers Potential Targets of Xuefu Zhuyu Decoction Against Traumatic Brain Injury in Rat

Xuefu Zhuyu decoction (XFZYD) performs multiple functions for traumatic brain injury (TBI) treatment. However, its clinical application is limited by the incomplete exploration of targets and inadequate discussion of mechanisms. We aimed to investigate the metabolic alterations of XFZYD in acute and chronic stages of TBI. Sprague-Dawley rats were randomly divided into the sham, controlled cortical impact (CCI) and XFZYD group. Behavioral and histopathological tests were used to evaluate the neuroprotective effects. Coagulation assays were performed to assess safety. Moreover, we analyzed the metabolomic profiling of hippocampal samples with different time intervals after CCI by high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). Differential metabolites were screened by multivariate data analysis. To further uncover the association between candidate metabolites and biological interaction networks, we applied bioinformatics analysis using MetaboAnalyst 4.0, STITCH 5.0 and TCMSP. The potential mechanism was verified by ELISA and Western blot. XFZYD ameliorated neurological deficiencies post-CCI without impairing blood coagulation in the rat’s model. Seventeen and fourteen metabolites were filtered on d 3 and 21, respectively. Eleven of potential metabolites were common at these time points, involving two significant pathways (arginine and proline metabolism, phenylalanine, tyrosine and tryptophan biosynthesis). Gamma-aminobutyric acid (GABA) and the related pathways were specifically affected by XFZYD at the acute phase of TBI, while biosynthesis of amino acids was the major pathway influenced at the chronic phase. This study provides broad insights into the therapeutic effects of XFZYD in treating TBI through the whole phases.

Novel Approaches for Omega-3 Fatty Acid Therapeutics: Chronic Versus Acute Administration to Protect Heart, Brain, and Spinal Cord

This article reviews novel approaches for omega-3 fatty acid (FA) therapeutics and the linked molecular mechanisms in cardiovascular and central nervous system (CNS) diseases. In vitro and in vivo research studies indicate that omega-3 FAs affect synergic mechanisms that include modulation of cell membrane fluidity, regulation of intracellular signaling pathways, and production of bioactive mediators. We compare how chronic and acute treatments with omega-3 FAs differentially trigger pathways of protection in heart, brain, and spinal cord injuries. We also summarize recent omega-3 FA randomized clinical trials and meta-analyses and discuss possible reasons for controversial results, with suggestions on improving the study design for future clinical trials. Acute treatment with omega-3 FAs offers a novel approach for preserving cardiac and neurological functions, and the combinations of acute treatment with chronic administration of omega-3 FAs might represent an additional therapeutic strategy for ameliorating adverse cardiovascular and CNS outcomes.

Plasma Lipidomic Analyses in Cohorts With mTBI and/or PTSD Reveal Lipids Differentially Associated With Diagnosis and APOE ε4 Carrier Status

The differential diagnosis between mild Traumatic Brain Injury (mTBI) sequelae and Post-Traumatic Stress Disorder (PTSD) is challenging due to their symptomatic overlap and co-morbidity. As such, there is a need to develop biomarkers which can help with differential diagnosis of these two conditions. Studies from our group and others suggest that blood and brain lipids are chronically altered in both mTBI and PTSD. Therefore, examining blood lipids presents a minimally invasive and cost-effective approach to identify promising biomarkers of these conditions. Using liquid chromatography-mass spectrometry (LC-MS) we examined hundreds of lipid species in the blood of healthy active duty soldiers (n = 52) and soldiers with mTBI (n = 21), PTSD (n = 34) as well as co-morbid mTBI and PTSD (n = 13) to test whether lipid levels were differentially altered with each. We also examined if the apolipoprotein E (APOE) ε4 allele can affect the association between diagnosis and peripheral lipid levels in this cohort. We show that several lipid classes are altered with diagnosis and that there is an interaction between diagnosis and the ε4 carrier status on these lipids. Indeed, total lipid levels as well as both the degree of unsaturation and chain lengths are differentially altered with diagnosis and ε4 status, specifically long chain unsaturated triglycerides (TG) and both saturated and mono-unsaturated diglycerides (DG). Additionally, an examination of lipid species reveals distinct profiles in each diagnostic group stratified by ε4 status, mainly in TG, saturated DG species and polyunsaturated phosphatidylserines. In summary, we show that peripheral lipids are promising biomarker candidates to assist with the differential diagnosis of mTBI and PTSD. Further, ε4 carrier status alone and in interaction with diagnosis has a strong influence on peripheral lipid levels. Therefore, examining ε4 status along with peripheral lipid levels could help with differential diagnosis of mTBI and PTSD.

Metabolic perturbations after pediatric TBI: It's not just about glucose

Improved patient survival following pediatric traumatic brain injury (TBI) has uncovered a currently limited understanding of both the adaptive and maladaptive metabolic perturbations that occur during the acute and long-term phases of recovery. While much is known about the redundancy of metabolic pathways that provide adequate energy and substrates for normal brain growth and development, the field is only beginning to characterize perturbations in these metabolic pathways after pediatric TBI. To date, the majority of studies have focused on dysregulated oxidative glucose metabolism after injury; however, the immature brain is well-equipped to use alternative substrates to fuel energy production, growth, and development. A comprehensive understanding of metabolic changes associated with pediatric TBI cannot be limited to investigations of glucose metabolism alone. All energy substrates used by the brain should be considered in developing nutritional and pharmacological interventions for pediatric head trauma. This review summarizes post-injury changes in brain metabolism of glucose, lipids, ketone bodies, and amino acids with discussion of the therapeutic potential of altering substrate utilization to improve pediatric TBI outcomes.

Treatment of Acute Sports-Related Concussion

PURPOSE OF REVIEW

Here, we summarize the current scientific literature on the management of sports-related concussion (SRC) in the acute period (< 6 weeks post-injury) with a focus on rest, return to learn, return to play, and emerging treatments.

RECENT FINDINGS

While relative rest is recommended for the first 24-48 h following acute SRC, the most recent guidelines highlight the lack of evidence for complete rest and in fact show that prolonged cognitive and physical rest can be detrimental. Gradual return to learn and play is recommended. Return to sport should only occur once the patient is symptom free. While there are no FDA-approved medications for acute treatment of concussion, there is preclinical data for the benefit of omega 3 fatty acids. Evidence is limited around the benefits of treating sleep disorders, vestibular-ocular dysfunction, and neck pain in the acute period. After 24-48 h of rest, SRC patients may gradually resume cognitive and physical activity. More research is needed to determine if any supplements, medications, and/or physical therapy are indicated in the management in acute SRC.

Long-term dietary intervention with low Phe and/or a specific nutrient combination improve certain aspects of brain functioning in phenylketonuria (PKU)

INTRODUCTION

In phenylketonuria (PKU), a gene mutation in the phenylalanine metabolic pathway causes accumulation of phenylalanine (Phe) in blood and brain. Although early introduction of a Phe-restricted diet can prevent severe symptoms from developing, patients who are diagnosed and treated early still experience deficits in cognitive functioning indicating shortcomings of current treatment. In the search for new and/or additional treatment strategies, a specific nutrient combination (SNC) was postulated to improve brain function in PKU. In this study, a long-term dietary intervention with a low-Phe diet, a specific combination of nutrients designed to improve brain function, or both concepts together was investigated in male and female BTBR PKU and WT mice.

MATERIAL & METHODS

48 homozygous wild-types (WT, +/+) and 96 PKU BTBRPah2 (-/-) male and female mice received dietary interventions from postnatal day 31 till 10 months of age and were distributed in the following six groups: high Phe diet (WT C-HP, PKU C-HP), high Phe plus specific nutrient combination (WT SNC-HP, PKU SNC-HP), PKU low-Phe diet (PKU C-LP), and PKU low-Phe diet plus specific nutrient combination (PKU SNC- LP). Memory and motor function were tested at time points 3, 6, and 9 months after treatment initiation in the open field (OF), novel object recognition test (NOR), spatial object recognition test (SOR), and the balance beam (BB). At the end of the experiments, brain neurotransmitter concentrations were determined.

RESULTS

In the NOR, we found that PKU mice, despite being subjected to high Phe conditions, could master the task on all three time points when supplemented with SNC. Under low Phe conditions, PKU mice on control diet could master the NOR at all three time points, while PKU mice on the SNC supplemented diet could master the task at time points 6 and 9 months. SNC supplementation did not consistently influence the performance in the OF, SOR or BB in PKU mice. The low Phe diet was able to normalize concentrations of norepinephrine and serotonin; however, these neurotransmitters were not influenced by SNC supplementation.

CONCLUSION

This study demonstrates that both a long-lasting low Phe diet, the diet enriched with SNC, as well as the combined diet was able to ameliorate some, but not all of these PKU-induced abnormalities. Specifically, this study is the first long-term intervention study in BTBR PKU mice that shows that SNC supplementation can specifically improve novel object recognition.

Nutrient Composition Comparison between the Low Saturated Fat Swank Diet for Multiple Sclerosis and Healthy U.S.-Style Eating Pattern

Multiple sclerosis (MS) is an incurable degenerative disease that attacks the central nervous system. Roy Swank proposed a low saturated fat diet to treat MS around 1950 and showed delayed disease progression in his patients. However, there is insufficient evidence to recommend this diet for MS and default dietary recommendations are the Dietary Guidelines for Americans (DGA). This study assessed the nutritional adequacy of seven-day menus developed by Swank and their compliance with the DGA; menus were modeled for comparison with the DGA Healthy US-Style Eating Pattern (HEP) for males and females 31⁻50 years. Swank recommended dietary supplements corrected menu shortfalls in vitamins D, E, calcium, folate and iron but not dietary fiber, potassium and choline. Healthy Eating Index-2015 score for Swank menus (93.2/100) indicated good compliance with the DGA. Nutritional adequacy of the Swank modeled diet was similar to HEP for 17 vitamins and minerals (Mean Adequacy Ratios ≥94%) with similar shortfall nutrients except magnesium (HEP males) and dietary fiber (Swank males). Alternate Healthy Eating Index-2010 scores for Swank male (90/110) and female (88/110) model diets were similar to HEP. Swank menus have similar nutritional adequacy as HEP. Inclusion of foods high in dietary fiber, potassium and choline may be advised as well as selection of foods to reduce sodium below the Tolerable Upper Intake Level.

Nutrient Composition Comparison between a Modified Paleolithic Diet for Multiple Sclerosis and the Recommended Healthy U.S.-Style Eating Pattern

Multiple sclerosis (MS) is a demyelinating disease that attacks the central nervous system. Evidence-based dietary guidelines do not exist for MS; the default advice is to follow the Dietary Guidelines for Americans (DGA). A modified Paleolithic Wahls Elimination (WahlsElim) diet promoted for MS excludes grains and dairy and encourages 9+ cups fruits and vegetables (F/V) and saturated fat for cooking. This study evaluated the nutritional adequacy of seven-day menus and modeled them with varying amounts of F/V for comparison with the DGA Healthy US-Style Eating Pattern (HEP) for ages 31–50 years. WahlsElim menus had low added sugar and glycemic index. Nutritional adequacy of the menus and modeled versions were similar to HEP for 17 vitamins and minerals (mean adequacy ratio ≥92%). Nutrient shortfalls for the modeled diet with 60% F/V were identical to HEP for vitamin D, iron (females), magnesium (marginally males), choline and potassium; this modeled diet was also low in dietary fiber and calcium but met vitamin E requirements while HEP did not. WahlsElim-prescribed supplements corrected vitamin D and magnesium shortfalls; careful selection of foods are needed to meet requirements of other shortfall nutrients and reduce saturated fat and sodium. Doctors should monitor nutritional status, supplement doses, and possible contraindications to high vitamin K intake in individuals following the WahlsElim diet.

Long-Term Effects of Traumatic Brain Injury on Anxiety-Like Behaviors in Mice: Behavioral and Neural Correlates

Traumatic brain injury (TBI) has been frequently linked to affective disorders such as anxiety and depression. However, much remains to be understood about the underlying molecular and signaling mechanisms that mediate affective dysfunctions following injury. A lack of consensus in animal studies regarding what the affective sequelae of TBI are has been a major hurdle that has slowed progress, with studies reporting the full range of effects: increase, decrease, and no change in anxiety following injury. Here, we addressed this issue directly by investigating long-term anxiety outcomes in mice following a moderate to severe controlled cortical impact (CCI) injury using a battery of standard behavioral tests-the open field (OF), elevated zero maze (EZM), and elevated plus maze (EPM). Mice were tested on weeks 1, 3, 5 and 7 post-injury. Our results show that the effect of injury is time- and task-dependent. Early on-up to 3 weeks post-injury, there is an increase in anxiety-like behaviors in the elevated plus and zero mazes. However, after 5 weeks post-injury, anxiety-like behavior decreases, as measured in the OF and EZM. Immunostaining in the basolateral amygdala (BLA) for GAD, a marker for GABA, at the end of the behavioral testing showed the late decrease in anxiety behavior was correlated with upregulation of inhibition. The approach adopted in this study reveals a complex trajectory of affective outcomes following injury, and highlights the importance of comparing outcomes in different assays and time-points, to ensure that the affective consequences of injury are adequately assessed.

Microglia in Alzheimer's Disease: Risk Factors and Inflammation

Microglia are resident immune cells in the central nervous system (CNS) that originate from myeloid progenitor cells in the embryonic yolk sac and are maintained independently of circulating monocytes throughout life. In the healthy state, microglia are highly dynamic and control the environment by rapidly extending and retracting their processes. When the CNS is inflamed, microglia can give rise to macrophages, but the regulatory mechanisms underlying this process have not been fully elucidated. Recent genetic studies have suggested that microglial function is compromised in Alzheimer's disease (AD), and that environmental factors such as diet and brain injury also affect microglial activation. In addition, studies of triggering receptor expressed on myeloid cells 2-deficiency in AD mice revealed heterogeneous microglial reactions at different disease stages, complicating the therapeutic strategy for AD. In this paper, we describe the relationship between genetic and environmental risk factors and the roles of microglia in AD pathogenesis, based on studies performed in human patients and animal models. We also discuss the mechanisms of inflammasomes and neurotransmitters in microglia, which accelerate the development of amyloid-β and tau pathology.