scholarly journals Peripheral Infection after Traumatic Brain Injury Augments Excitability in the Perilesional Cortex and Dentate Gyrus

Biomedicines ◽  
2021 ◽  
Vol 9 (12) ◽  
pp. 1946
Author(s):  
Ying Wang ◽  
Pedro Andrade ◽  
Asla Pitkänen
Keyword(s):  
Traumatic Brain Injury ◽  
Brain Injury ◽  
Dentate Gyrus ◽  
Sham Operation ◽  
Seizure Susceptibility ◽  
Neuronal Activation ◽  
Post Injury ◽  
Ptz Test ◽  
Peripheral Infection ◽  
Lps Treatment

Peripheral infections occur in up to 28% of patients with traumatic brain injury (TBI), which is a major etiology for structural epilepsies. We hypothesized that infection occurring after TBI acts as a “second hit” and facilitates post-traumatic epileptogenesis. Adult male Sprague–Dawley rats were subjected to lateral fluid-percussion injury or sham-operation. At 8 weeks post-injury, rats were treated with lipopolysaccharide (LPS, 5 mg/kg) to mimic Gram-negative peripheral infection. T2-weighted magnetic resonance imaging was used to detect the cortical lesion type (small focal inflammatory [TBIFI] vs. large cavity-forming [TBICF]). Spontaneous seizures were detected with video-electroencephalography, and seizure susceptibility was determined by the pentylenetetrazole (PTZ) test. Post-PTZ neuronal activation was assessed using c-Fos immunohistochemistry. LPS treatment increased the percentage of rats with PTZ-induced seizures among animals with TBIFI lesions (p < 0.05). It also increased the cumulative duration of PTZ-induced seizures (p < 0.01), particularly in the TBIFI group (p < 0.05). The number of c-Fos immunopositive cells was higher in the perilesional cortex of injured animals compared with sham-operated animals (p < 0.05), particularly in the TBI-LPS group (p < 0.05). LPS treatment increased the percentage of injured rats with bilateral c-Fos staining in the dentate gyrus (p < 0.05), particularly in the TBIFI group (p < 0.05). Our findings demonstrate that peripheral infection after TBI increases PTZ-induced seizure susceptibility and neuronal activation in the perilesional cortex and bilaterally in the dentate gyrus, particularly in animals with prolonged perilesional T2 enhancement. Our data suggest that treatment of infections and reduction of post-injury neuro-inflammation are important components of the treatment regimen aiming at preventing epileptogenesis after TBI.

scholarly journals Post-injury ventricular enlargement associates with iron in choroid plexus but not with seizure susceptibility nor lesion atrophy—6-month MRI follow-up after experimental traumatic brain injury

2021 ◽  
Author(s):  
Amna Yasmin ◽  
Asla Pitkänen ◽  
Pedro Andrade ◽  
Tomi Paananen ◽  
Olli Gröhn ◽  
...  
Keyword(s):  
Traumatic Brain Injury ◽  
Brain Injury ◽  
Choroid Plexus ◽  
Memory Function ◽  
Cortical Lesion ◽  
Seizure Susceptibility ◽  
Ventricular Enlargement ◽  
Mri Findings ◽  
Post Injury ◽  
Iron Load

AbstractVentricular enlargement is one long-term consequence of a traumatic brain injury, and a risk factor for memory disorders and epilepsy. One underlying mechanisms of the chronic ventricular enlargement is disturbed cerebrospinal-fluid secretion or absorption by choroid plexus. We set out to characterize the different aspects of ventricular enlargement in lateral fluid percussion injury (FPI) rat model by magnetic resonance imaging (MRI) and discovered choroid plexus injury in rats that later developed hydrocephalus. We followed the brain pathology progression for 6 months and studied how the ventricular growth was associated with the choroid plexus injury, cortical lesion expansion, hemorrhagic load or blood perfusion deficits. We correlated MRI findings with the seizure susceptibility in pentylenetetrazol challenge and memory function in Morris water-maze. Choroid plexus injury was validated by ferric iron (Prussian blue) and cytoarchitecture (Nissl) stainings. We discovered choroid plexus injury that accumulates iron in 90% of FPI rats by MRI. The amount of the choroid plexus iron remained unaltered 1-, 3- and 6-month post-injury. During this time, the ventricles kept on growing bilaterally. Ventricular growth did not depend on the cortical lesion severity or the cortical hemorrhagic load suggesting a separate pathology. Instead, the results indicate choroidal injury as one driver of the post-traumatic hydrocephalus, since the higher the choroid plexus iron load the larger were the ventricles at 6 months. The ventricle size or the choroid plexus iron load did not associate with seizure susceptibility. Cortical hypoperfusion and memory deficits were worse in rats with greater ventricular growth.

scholarly journals Ketogenic Diet as a potential treatment for traumatic brain injury in mice

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Meirav Har-Even ◽  
Vardit Rubovitch ◽  
Whitney A. Ratliff ◽  
Bar Richmond-Hacham ◽  
Bruce A. Citron ◽  
...  
Keyword(s):  
Traumatic Brain Injury ◽  
Brain Injury ◽  
Dentate Gyrus ◽  
Ketogenic Diet ◽  
Cognitive Abilities ◽  
Ketone Bodies ◽  
Temporal Cortex ◽  
Closed Head Injury ◽  
Standard Diet ◽  
Post Injury

AbstractTraumatic brain injury (TBI) is a brain dysfunction without present treatment. Previous studies have shown that animals fed ketogenic diet (KD) perform better in learning tasks than those fed standard diet (SD) following brain injury. The goal of this study was to examine whether KD is a neuroprotective in TBI mouse model. We utilized a closed head injury model to induce TBI in mice, followed by up to 30 days of KD/SD. Elevated levels of ketone bodies were confirmed in the blood following KD. Cognitive and behavioral performance was assessed post injury and molecular and cellular changes were assessed within the temporal cortex and hippocampus. Y-maze and Novel Object Recognition tasks indicated that mTBI mice maintained on KD displayed better cognitive abilities than mTBI mice maintained on SD. Mice maintained on SD post-injury demonstrated SIRT1 reduction when compared with uninjured and KD groups. In addition, KD management attenuated mTBI-induced astrocyte reactivity in the dentate gyrus and decreased degeneration of neurons in the dentate gyrus and in the cortex. These results support accumulating evidence that KD may be an effective approach to increase the brain’s resistance to damage and suggest a potential new therapeutic strategy for treating TBI.

scholarly journals Ketogenic Diet as a Potential Treatment for Traumatic Brain Injury in Mice

2021 ◽  
Author(s):  
Meirav Har-Even ◽  
Vardit Rubovitch ◽  
Whitney A. Ratliff ◽  
Bruce A. Citron ◽  
Chaim G. Pick
Keyword(s):  
Traumatic Brain Injury ◽  
Brain Injury ◽  
Dentate Gyrus ◽  
Ketogenic Diet ◽  
Ketone Bodies ◽  
Standard Diet ◽  
Post Injury ◽  
Maze Test ◽  
Y Maze ◽  
Primary Mouse

Abstract Background: Traumatic brain injury (TBI) is a brain dysfunction without present treatment. Previous studies have shown that animals fed a ketogenic diet (KD) perform better in learning tasks than those fed a standard diet (SD) following brain injury. The goal of this study was to examine whether KD is neuroprotective in a TBI mouse model. Methods: We utilized a closed head injury model to induce mild TBI (mTBI) in mice. Mice were fed KD or SD starting immediately following the trauma and throughout the following 30 days. Tail blood ketone bodies levels were checked at 0, 3, 7 and 30 days post injury. Behavioral tests took place at 7 and 30days post injury, visual and spatial memory impairments were assessed using the Novel object recognition (NOR) paradigm and the Y-maze test, respectively, and anxiety-like behavior was assessed using the elevated plus maze test. Primary mouse SIRT1 levels antibodies were used to detect changes in protein levels following TBI induction and treatments 7 and 30 days post injury and Immunohistochemical sections were stained with, NeuN (for mature neurons), Iba-1 (for microglia) and GFAP (for astrocyte). Results: Elevated levels of ketone bodies were confirmed in the blood following KD. Cognitive and behavioral performance was assessed post injury and molecular and cellular changes were assessed within the temporal cortex and hippocampus. Y‑maze and NOR tasks indicated that mTBI mice maintained on KD displayed better cognitive abilities than mTBI mice maintained on SD. Mice maintained on SD post-injury demonstrated SIRT1 reduction when compared with uninjured and KD groups. In addition, KD management attenuated mTBI-induced microglia activation and astrocyte reactivity in the dentate gyrus and decreased degeneration of neurons in the dentate gyrus and in the cortex. Conclusion: These results support accumulating evidence that KD may be an effective approach to increase the brain’s resistance to damage and suggest a potential new therapeutic strategy for treating mTBI.

scholarly journals Blockade of TRPC Channels Limits Cholinergic-Driven Hyperexcitability and Seizure Susceptibility After Traumatic Brain Injury

2021 ◽  
Vol 15 ◽  
Author(s):  
Chase M. Carver ◽  
Haley R. DeWitt ◽  
Aiola P. Stoja ◽  
Mark S. Shapiro
Keyword(s):  
Traumatic Brain Injury ◽  
Brain Injury ◽  
Dentate Gyrus ◽  
Transient Receptor Potential ◽  
Brain Slices ◽  
Receptor Activation ◽  
Cholinergic Innervation ◽  
Trpc Channels ◽  
Seizure Susceptibility ◽  
Male Adult

We investigated the contribution of excitatory transient receptor potential canonical (TRPC) cation channels to posttraumatic hyperexcitability in the brain 7 days following controlled cortical impact model of traumatic brain injury (TBI) to the parietal cortex in male adult mice. We investigated if TRPC1/TRPC4/TRPC5 channel expression is upregulated in excitatory neurons after TBI in contribution to epileptogenic hyperexcitability in key hippocampal and cortical circuits that have substantial cholinergic innervation. This was tested by measuring TRPC1/TRPC4/TRPC5 protein and messenger RNA (mRNA) expression, assays of cholinergic function, neuronal Ca2+ imaging in brain slices, and seizure susceptibility after TBI. We found region-specific increases in expression of TRPC1, TRPC4, and TRPC5 subunits in the hippocampus and cortex following TBI. The dentate gyrus, CA3 region, and cortex all exhibited robust upregulation of TRPC4 mRNA and protein. TBI increased cFos activity in dentate gyrus granule cells (DGGCs) and layer 5 pyramidal neurons both at the time of TBI and 7 days post-TBI. DGGCs displayed greater magnitude and duration of acetylcholine-induced rises in intracellular Ca2+ in brain slices from mice subjected to TBI. The TBI mice also exhibited greater seizure susceptibility in response to pentylenetetrazol-induced kindling. Blockade of TRPC4/TRPC5 channels with M084 reduced neuronal hyperexcitation and impeded epileptogenic progression of kindling. We observed that the time-dependent upregulation of TRPC4/TRPC5-containing channels alters cholinergic responses and activity of principal neurons acting to increase proexcitatory sensitivity. The underlying mechanism includes acutely decreased acetylcholinesterase function, resulting in greater Gq/11-coupled muscarinic receptor activation of TRPC channels. Overall, our evidence suggests that TBI-induced plasticity of TRPC channels strongly contributes to overt hyperexcitability and primes the hippocampus and cortex for seizures.

scholarly journals A-126 Clinical Utility of Risk Factors to Predict Self-reported Neurobehavioral Outcome Following Traumatic Brain Injury: PTSD, Sleep, Resilience, and Lifetime Blast Exposure

2020 ◽  
Vol 35 (6) ◽  
pp. 919-919
Author(s):  
Lange R ◽  
Lippa S ◽  
Hungerford L ◽  
Bailie J ◽  
French L ◽  
...  
Keyword(s):  
Risk Factors ◽  
Traumatic Brain Injury ◽  
Risk Factor ◽  
Brain Injury ◽  
Clinical Utility ◽  
Poor Sleep ◽  
Post Injury ◽  
Poor Outcome ◽  
Blast Exposure ◽  
Neurobehavioral Outcome

Abstract Objective To examine the clinical utility of PTSD, Sleep, Resilience, and Lifetime Blast Exposure as ‘Risk Factors’ for predicting poor neurobehavioral outcome following traumatic brain injury (TBI). Methods Participants were 993 service members/veterans evaluated following an uncomplicated mild TBI (MTBI), moderate–severe TBI (ModSevTBI), or injury without TBI (Injured Controls; IC); divided into three cohorts: (1) &lt; 12 months post-injury, n = 237 [107 MTBI, 71 ModSevTBI, 59 IC]; (2) 3-years post-injury, n = 370 [162 MTBI, 80 ModSevTBI, 128 IC]; and (3) 10-years post-injury, n = 386 [182 MTBI, 85 ModSevTBI, 119 IC]. Participants completed a 2-hour neurobehavioral test battery. Odds Ratios (OR) were calculated to determine whether the ‘Risk Factors’ could predict ‘Poor Outcome’ in each cohort separately. Sixteen Risk Factors were examined using all possible combinations of the four risk factor variables. Poor Outcome was defined as three or more low scores (&lt; 1SD) on five TBI-QOL scales (e.g., Fatigue, Depression). Results In all cohorts, the vast majority of risk factor combinations resulted in ORs that were ‘clinically meaningful’ (ORs &gt; 3.00; range = 3.15 to 32.63, all p’s &lt; .001). Risk factor combinations with the highest ORs in each cohort were PTSD (Cohort 1 & 2, ORs = 17.76 and 25.31), PTSD+Sleep (Cohort 1 & 2, ORs = 18.44 and 21.18), PTSD+Sleep+Resilience (Cohort 1, 2, & 3, ORs = 13.56, 14.04, and 20.08), Resilience (Cohort 3, OR = 32.63), and PTSD+Resilience (Cohort 3, OR = 24.74). Conclusions Singularly, or in combination, PTSD, Poor Sleep, and Low Resilience were strong predictors of poor outcome following TBI of all severities and injury without TBI. These variables may be valuable risk factors for targeted early interventions following injury.

scholarly journals The Challenge of Managing Patients Suffering from TBI: The Utility of Multiparametric MRI

CNS Spectrums ◽  
2021 ◽  
Vol 26 (2) ◽  
pp. 178-179
Author(s):  
John L. Sherman ◽  
Laurence J. Adams ◽  
Christen F. Kutz ◽  
Deborah York ◽  
Mitchell S. Szymczak
Keyword(s):  
Traumatic Brain Injury ◽  
Brain Injury ◽  
Family History ◽  
Diffusion Tensor ◽  
Multiparametric Mri ◽  
Psychiatric History ◽  
Post Injury ◽  
Negative Family History ◽  
Imaging Result ◽  
The Brain

AbstractTraumatic brain injury (TBI) is a complex phenomenon affecting multiple areas of the brain in multiple ways. Both right and left hemispheres are affected as well as supratentorial and infratentorial compartments. These multifocal injuries are caused by many factors including acute mechanical injury, focal intracranial hemorrhage, blunt and rotational forces, epidural and subdural hematoma, hypoxemia, hypotension, edema, axonal damage, neuronal death, gliosis and blood brain barrier disruption. Clinicians and patients benefit by precise information about the neuroanatomical areas that are affected macroscopically, microscopically and biochemically in an individual patient.Standard imaging studies are frequently negative or grossly underestimate the severity of TBI and may exacerbate and prolong patient suffering with an imaging result of “no significant abnormality”. Specifically, sophisticated imaging tools have been developed which reveal significant damage to the brain structure including atrophy, MRI spectroscopy showing variations in neuronal metabolite N-acetyl-aspartate, elevations of membrane related Choline, and the glial metabolite myo-inositol is often observed to be increased post injury. In addition, susceptibility weighted imaging (SWI) has been shown to be more reliable for detecting microbleeds versus calcifications.We have selected two TBI patients with diffuse traumatic brain injury.The first patient is a 43-year-old male who suffered severe traumatic brain injury from a motorcycle accident in 2016. Following the accident, the patient was diagnosed with seizures, major depression, and intermittent explosive disorder. He has attempted suicide and has neurobehavioral disinhibition including severe anger, agitation and irritability. He denies psychiatric history prior to TBI and has negative family history. Following the TBI, he became physically aggressive and assaultive in public with minimal provocation. He denies symptoms of thought disorder and mania. He is negative for symptoms of  cognitive decline or encephalopathy.The second patient is a 49-year-old male who suffered at least 3 concussive blasts in the Army and a parachute injury. Following the last accident, the patient was diagnosed with major depressive disorder, panic disorder, PTSD and generalized anxiety disorder. He denies any psychiatric history prior to TBI including negative family history of psychiatric illness. In addition, he now suffers from nervousness, irritability, anger, emotional lability and concurrent concentration issues, problems completing tasks and alterations in memory.Both patients underwent 1.5T multiparametric MRI using standard T2, FLAIR, DWI and T1 sequences, and specialized sequences including susceptibility weighted (SWAN/SWI), 3D FLAIR, single voxel MRI spectroscopy (MRS), diffusion tensor imaging (DTI), arterial spin labeling perfusion (ASL) and volumetric MRI (NeuroQuant). Importantly, this exam can be performed in 30–45 minutes and requires no injections other than gadolinium in some patients. We will discuss the insights derived from the MRI which detail the injured areas, validate the severity of the brain damage, and provide insight into the psychological, motivational and physical disabilities that afflict these patients. It is our expectation that this kind of imaging study will grow in value as we link specific patterns of injury to specific symptoms and syndromes resulting in more targeted therapies in the future.

Blood Biomarkers Relate to Cognitive Performance Years after Traumatic Brain Injury in Service Members and Veterans

2020 ◽  
pp. 1-7
Author(s):  
Sara M. Lippa ◽  
Jessica Gill ◽  
Tracey A. Brickell ◽  
Louis M. French ◽  
Rael T. Lange
Keyword(s):  
Traumatic Brain Injury ◽  
Brain Injury ◽  
Cognitive Outcome ◽  
Service Members ◽  
Neurocognitive Performance ◽  
Blood Biomarkers ◽  
Post Injury ◽  
Blood Draw ◽  
Neurofilament Light ◽  
History Of

Abstract Objective: This study examines the relationship of serum total tau, neurofilament light (NFL), ubiquitin carboxyl-terminal hydrolase L1 (UCH-L1), and glial fibrillary acidic protein (GFAP) with neurocognitive performance in service members and veterans with a history of traumatic brain injury (TBI). Method: Service members (n = 488) with a history of uncomplicated mild (n = 172), complicated mild, moderate, severe, or penetrating TBI (sTBI; n = 126), injured controls (n = 116), and non-injured controls (n = 74) prospectively enrolled from Military Treatment Facilities. Participants completed a blood draw and neuropsychological assessment a year or more post-injury. Six neuropsychological composite scores and presence/absence of mild neurocognitive disorder (MNCD) were evaluated. Within each group, stepwise hierarchical regression models were conducted. Results: Within the sTBI group, increased serum UCH-L1 was related to worse immediate memory and delayed memory (R2Δ = .065–.084, ps < .05) performance, while increased GFAP was related to worse perceptual reasoning (R2Δ = .030, p = .036). Unexpectedly, within injured controls, UCH-L1 and GFAP were inversely related to working memory (R2Δ = .052–.071, ps < .05), and NFL was related to executive functioning (R2Δ = .039, p = .021) and MNCD (Exp(B) = 1.119, p = .029). Conclusions: Results suggest GFAP and UCH-L1 could play a role in predicting poor cognitive outcome following complicated mild and more severe TBI. Further investigation of blood biomarkers and cognition is warranted.

scholarly journals Chronic complement dysregulation drives neuroinflammation after traumatic brain injury: a transcriptomic study

2021 ◽  
Vol 9 (1) ◽  
Author(s):  
Amer Toutonji ◽  
Mamatha Mandava ◽  
Silvia Guglietta ◽  
Stephen Tomlinson
Keyword(s):  
Gene Expression ◽  
Traumatic Brain Injury ◽  
Brain Injury ◽  
Complement System ◽  
Classical Pathway ◽  
Post Injury ◽  
Complement Inhibition ◽  
Time Points ◽  
Complement Gene ◽  
The Complement System

AbstractActivation of the complement system propagates neuroinflammation and brain damage early and chronically after traumatic brain injury (TBI). The complement system is complex and comprises more than 50 components, many of which remain to be characterized in the normal and injured brain. Moreover, complement therapeutic studies have focused on a limited number of histopathological outcomes, which while informative, do not assess the effect of complement inhibition on neuroprotection and inflammation in a comprehensive manner. Using high throughput gene expression technology (NanoString), we simultaneously analyzed complement gene expression profiles with other neuroinflammatory pathway genes at different time points after TBI. We additionally assessed the effects of complement inhibition on neuropathological processes. Analyses of neuroinflammatory genes were performed at days 3, 7, and 28 post injury in male C57BL/6 mice following a controlled cortical impact injury. We also characterized the expression of 59 complement genes at similar time points, and also at 1- and 2-years post injury. Overall, TBI upregulated the expression of markers of astrogliosis, immune cell activation, and cellular stress, and downregulated the expression of neuronal and synaptic markers from day 3 through 28 post injury. Moreover, TBI upregulated gene expression across most complement activation and effector pathways, with an early emphasis on classical pathway genes and with continued upregulation of C2, C3 and C4 expression 2 years post injury. Treatment using the targeted complement inhibitor, CR2-Crry, significantly ameliorated TBI-induced transcriptomic changes at all time points. Nevertheless, some immune and synaptic genes remained dysregulated with CR2-Crry treatment, suggesting adjuvant anti-inflammatory and neurotropic therapy may confer additional neuroprotection. In addition to characterizing complement gene expression in the normal and aging brain, our results demonstrate broad and chronic dysregulation of the complement system after TBI, and strengthen the view that the complement system is an attractive target for TBI therapy.

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