Evidence for the therapeutic efficacy of either mild hypothermia or oxygen radical scavengers after repetitive mild traumatic brain injury

Aconitum coreanum and processed products on its base prevent stroke via the PI3K/Akt and KEAP1/NRF2 in the in vivo study

Aconitum coreanum (A. coreanum), a traditional Chinese medicine, has been proved to treat ischemic stroke (IS). However, the mechanisms of A. coreanum's anti-stroke is currently unknown. This study aimed to uncover the effect and mechanisms of A. coreanum. And study raw Aconitum coreanum (RA) and steamed Aconitum coreanum (SA) and Aconitum coreanum processed with ginger and Alumen (GA) on the mechanism of the pharmacological action of treating IS. Determining whether the efficacy is affected after processing. The right unilateral ligation of the carotid artery of gerbils was used to mimic IS. The neurological function score, infarct volume, oxidative stress level and inflammatory factor expression were measured in gerbils after IS. Western blot and immunofluorescence analyses were conducted to evaluate the expression of related proteins. Metabolomic analyzes IS-related metabolic pathways in urinary metabolites. RA, SA and GA significantly improved the infarct volume and behavioral score of IS gerbils, increased the expression of brain tissue superoxide dismutase (SOD), glutathione (GSH), nitric oxide (NO) and decreased the content of malondialdehyde (MDA), interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α). Western blot and immunofluorescence analysis results showed that RA, SA and GA significantly increased the expression of P-Akt, PI3K, HO-1 and KEAP1. Metabolomic studies identified 112 differential metabolites, including L-Proline, Riboflavin, Leukotriene D4, and 7-Methylxanthine, as potential biomarkers of stroke, involving 14 metabolic pathways including riboflavin metabolism, pyrimidine metabolism, and purine metabolism. Our findings indicated that A. coreanum protected against cerebral ischemia injury probably via the PI3K/Akt and KEAP1/NRF2 pathway. A. coreanum before and after processing both had a protective effect against IS brain injury in gerbils. The A. coreanum efficacy was not reduced after processing. Even compared to RA, SA had better efficacy.

Elemental iron protects gut microbiota against oxygen-induced dysbiosis

Gut dysbiosis induced by oxygen and reactive oxygen species may be related to the development of inflammation, resulting in metabolic syndrome and associated-conditions in the gut. Here we show that elemental iron can serve as an antioxidant and reverse the oxygen-induced dysbiosis. Fecal samples from three healthy donors were fermented with elemental iron and/or oxygen. 16S rRNA analysis revealed that elemental iron reversed the oxygen-induced disruption of Shannon index diversity of the gut microbiota.The bacteria lacking enzymatic antioxidant systems also increased after iron treatment. Inter-individual differences, which corresponded to iron oxidation patterns, were observed for the tested donors. Gut bacteria responding to oxygen and iron treatments were identified as guilds, among which, Escherichia-Shigella was promoted by oxygen and depressed by elemental iron, while changes in bacteria such as Bifidobacterium, Blautia, Eubacterium, Ruminococcaceae, Flavonifractor, Oscillibacter, and Lachnospiraceae were reversed by elemental iron after oxygen treatment. Short-chain fatty acid production was inhibited by oxygen and this effect was partially reversed by elemental iron. These results suggested that elemental iron can regulate the oxygen/ROS state and protect the gut microbiota from oxidative stress.

The Effect of Mild Hypothermia on Nogo-A and Neurological Function in the Brain after Cardiopulmonary Resuscitation in Rats

ObjectiveWe investigated the dynamic changes of Nogo-A protein in brain and the effects of mild therapeutic hypothermia (MTH) on its expression after cardiopulmonary resuscitation (CPR). Methods: Western-blotting and neurological scoring of 45 rats subjected to cardiac arrest and CPR with and without MTR were performed to investigate the changes in the expression of Nogo-A protein in the hippocampus and cortex over a period of time ranging from 6 h to 72 h after restoration of spontaneous circulation (ROSC). Results: Nogo-A expression levels were increased at 6 h after CPR in the hippocampus and cortex, peaked at 24 h in the cortex, and at 48 h in the hippocampus. The expression of Nogo-A in the MTR group was significantly lower at 12 h (p < 0.05) compared to those with no MTR after ROSC. Conclusions: MTR blunts the expression of Nogo-A protein in the hippocampus and cortex after cardiac arrest and resuscitation, and MTR may provide cerebral protection after ischemia.

Effect of intravenous thrombolysis combined with mild hypothermia on the levels of IL-1β, IL-6, ICAM-1 and MMP-2 in patients with acute cerebral infarction and clinical significance

The present study aimed to explore the effects and clinical importance of serum interleukin (IL) IL-1β, IL-6, C-reactive protein (CRP), intercellular adhesion molecule (ICAM)-1 and matrix metalloproteinase (MMP)-2 in patients with acute cerebral infarction undergoing intravenous thrombolysis during simultaneous hypothermia therapy. A total of 80 patients with acute cerebral infarction who were treated at our hospital were randomly selected. They were divided into groups A and B. The two groups were treated with intravenous thrombolysis, while group B received sub-hypothermia treatment. Prior to treatment and at 7 days after treatment, 5 ml of venous blood was collected and stored in a freezer at -80˚C. IL-1β, IL-6, CRP, ICAM-1 and MMP-2 levels were detected by ELISA and compared between the groups and time-points. The results were as follows: i) At 7 days after treatment, the levels of IL-1β, IL-6, CRP, ICAM-1 and MMP-2 in group B were significantly decreased compared with those in group A (P<0.05), while there was no significant difference of these levels between group A and B before treatment (P>0.05). The incidence of adverse reactions in group A and group B was 35 and 20% respectively, and the mortality rate was 10 and 5%, respectively. There were no significant differences in adverse events and mortality between the two groups (P>0.05). In addition, a positive correlation of the level of IL-1β, IL-6, CRP, ICAM-1 and MMP-2 with the National Institutes of Health Stroke Scale score was determined in the patients prior to treatment. In conclusion, mild hypothermia treatment in addition to intravenous thrombolysis significantly reduced the levels of IL-1β, IL-6, CRP, ICAM-1 and MMP-2 in patients with acute cerebral infarction and reduced inflammation, and should therefore be incorporated in clinical practice.

Intravenous thrombolysis in combination with mild hypothermia therapy in the treatment of acute cerebral infarction

Objective

To investigate the efficacy of recombinant tissue plasminogen activator (rt-PA) intravenous thrombolysis in combination with mild hypothermia therapy in the treatment of acute cerebral infarction.

Methods

One hundred and thirty-two patients with acute cerebral infarction who were admitted to our hospital were selected and grouped into a control group and an observation group, 66 each group. Patients in the control group were given conventional treatment in combination with local mild hypothermia therapy, and patients in the observation group were given rt-PA intravenous thrombolysis on the basis of conventional treatment and local mild hypothermia therapy. National institute of health stroke scale (NIHSS) score and intracranial pressure (ICP) of the two groups before and after treatment was recorded. The efficacy of the two groups was evaluated. The modified Rankin scale (MRS) score was followed up for three months. The blood samples of the patients were collected before and after thrombolysis. Superoxide dismutase (SOD) and malondialdehyde (MDA) levels in the plasma were detected.

Results

The NIHSS score of the two groups decreased in the 1^st, 3^rd and 7^th day after treatment compared to before treatment (p<0.05), but the NIHSS score of the two groups had no significant difference at different time points after treatment (p>0.05). The ICP of the two groups decreased in the 1^st, 3^rd and 7^th day after treatment compared to before treatment (p<0.05), and the decrease of ICP of the observation group was more significant than that of the control group at the same time point (1^st, 3^rd and 7^th day after treatment) (p<0.05). The clinical efficacy of the observation group was higher than that of the control group after treatment, and the difference was statistically significant (p<0.05). The MDA concentration of both groups decreased at different time points after treatment (p<0.05), but the SOD concentration increased (p<0.05). The MDA concentration of the observation group was lower than that of the control group at different time points after treatment (p<0.05), and the SOD concentration of the observation group was higher than that of the control group (p<0.05).

Conclusion

rt-PA intravenous thrombolysis in combination with mild hypothermia therapy has significant efficacy in the treatment of acute cerebral infarction. It can effectively relieve neurological function. Its action mechanism may be realized by relieving oxidative stress response.

Prospective, randomized, blinded, and placebo-controlled study of Cerebrolysin dose-response effects on long-term functional outcomes in a rat model of mild traumatic brain injury

Using a prospective, randomized, blinded, placebo-controlled protocol, the authors demonstrated that Cerebrolysin at doses of 0.8-7.5 ml/kg, administered 4 hours after injury and then once daily for a total of 10 consecutive days, improves long-term functional outcomes in a rat model of mild closed head injury; a 2.5-ml/kg dose was identified as optimal. These findings suggest that Cerebrolysin has the potential to treat mild traumatic brain injury, the incidence of which is high without effective treatments.

The Effects of a Combination of Ion Channel Inhibitors in Female Rats Following Repeated Mild Traumatic Brain Injury

Following mild traumatic brain injury (mTBI), the ionic homeostasis of the central nervous system (CNS) becomes imbalanced. Excess Ca²⁺ influx into cells triggers molecular cascades, which result in detrimental effects. The authors assessed the effects of a combination of ion channel inhibitors (ICI) following repeated mTBI (rmTBI). Adult female rats were subjected to two rmTBI weight-drop injuries 24 h apart, sham procedures (sham), or no procedures (normal). Lomerizine, which inhibits voltage-gated calcium channels, was administered orally twice daily, whereas YM872 and Brilliant Blue G, inhibiting α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) and P2X₇ receptors, respectively, were delivered intraperitoneally every 48 h post-injury. Vehicle treatment controls were included for rmTBI, sham, and normal groups. At 11 days following rmTBI, there was a significant increase in the time taken to cross the 3 cm beam, as a sub-analysis of neurological severity score (NSS) assessments, compared with the normal control (p < 0.05), and a significant decrease in learning-associated improvement in rmTBI in Morris water maze (MWM) trials relative to the sham (p < 0.05). ICI-treated rmTBI animals were not different to sham, normal controls, or rmTBI treated with vehicle in all neurological severity score and Morris water maze assessments (p > 0.05). rmTBI resulted in increases in microglial cell density, antioxidant responses (manganese-dependent superoxide dismutase (MnSOD) immunoreactivity), and alterations to node of Ranvier structure. ICI treatment decreased microglial density, MnSOD immunoreactivity, and abnormalities of the node of Ranvier compared with vehicle controls (p < 0.01). The authors' findings demonstrate the beneficial effects of the combinatorial ICI treatment on day 11 post-rmTBI, suggesting an attractive therapeutic strategy against the damage induced by excess Ca²⁺ following rmTBI.

Hypothermia ameliorates blast-related lifespan reduction of C. elegans

Blast-related mild traumatic brain injury induces significant long-term health issues, yet treatment procedures remain underdeveloped. Therapeutic hypothermia has been postulated as a potentially effective therapy. In a Caenorhabditis elegans model, we demonstrate a dose-dependent reduction in lifespan following exposure to blast-like shock waves. Using polyvinyl alcohol, we show that cavitation is a key injurious factor in the damaging shock wave component. Short and long lifespan C. elegans mutants demonstrated the interaction of genetic and environmental longevity-determining factors. Hypothermia reduced the long term effect of shock wave exposure. Thus, we present an effective C. elegans model of long term effects of blast-related mild traumatic brain injury, as well as evidence of the merit of therapeutic hypothermia as a therapy option following blast exposure.

Hyperthermia and Mild Traumatic Brain Injury: Effects on Inflammation and the Cerebral Vasculature

Mild traumatic brain injury (mTBI) or concussion represents the majority of brain trauma in the United States. The pathophysiology of mTBI is complex and may include both focal and diffuse injury patterns. In addition to altered circuit dysfunction and traumatic axonal injury (TAI), chronic neuroinflammation has also been implicated in the pathophysiology of mTBI. Recently, our laboratory has reported the detrimental effects of mild hyperthermic mTBI in terms of worsening histopathological and behavioral outcomes. To clarify the role of temperature-sensitive neuroinflammatory processes on these consequences, we evaluated the effects of elevated brain temperature (39°C) on altered microglia/macrophage phenotype patterns after mTBI, changes in leukocyte recruitment, and TAI. Sprague-Dawley male rats underwent mild parasagittal fluid-percussion injury under normothermic (37°C) or hyperthermic (39°C) conditions. Cortical and hippocampal regions were analyzed using several cellular and molecular outcome measures. At 24 h, the ratio of iNOS-positive (M1 type phenotype) to arginase-positive (M2 type phenotype) cells after hyperthermic mTBI showed an increase compared with normothermia by flow cytometry. Inflammatory response gene arrays also demonstrated a significant increase in several classes of pro-inflammatory genes with hyperthermia treatment over normothermia. The injury-induced expression of chemokine ligand 2 (Ccl2) and alpha-2-macroglobulin were also increased with hyperthermic mTBI. With western blot analysis, an increase in CD18 and intercellular cell adhesion molecule-1 (ICAM-1) with hyperthermia and a significant increase in Iba1 reactive microglia are reported in the cerebral cortex. Together, these results demonstrate significant differences in the cellular and molecular consequences of raised brain temperature at the time of mTBI. The observed polarization toward a M1-phenotype with mild hyperthermia would be expected to augment chronic inflammatory cascades, sustained functional deficits, and increased vulnerability to secondary insults. Mild elevations in brain temperature may contribute to the more severe and longer lasting consequences of mTBI or concussion reported in some patients.

iTRAQ-Based Quantitative Proteomics Reveals the New Evidence Base for Traumatic Brain Injury Treated with Targeted Temperature Management

This study aimed to investigate the effects of targeted temperature management (TTM) modulation on traumatic brain injury (TBI) and the involved mechanisms using quantitative proteomics technology. SH-SY5Y and HT-22 cells were subjected to moderate stretch injury using the cell injury controller (CIC), followed by incubation at TTM (mild hypothermia, 32°C), or normothermia (37°C). The real-time morphological changes, cell cycle phase distribution, death, and cell viability were evaluated. Moderate TBI was produced by the controlled cortical impactor (CCI), and the effects of TTM on the neurological damage, neurodegeneration, cerebrovascular histopathology, and behavioral outcome were determined in vivo. Results showed that TTM treatment prevented TBI-induced neuronal necrosis in the brain, achieved a substantial reduction in neuronal death both in vitro and in vivo, reduced cortical lesion volume and neuronal loss, attenuated cerebrovascular histopathological damage, brain edema, and improved behavioral outcome. Using an iTRAQ proteomics approach, proteins that were significantly associated with TTM in experimental TBI were identified. Importantly, changes in four candidate molecules (plasminogen [PLG], antithrombin III [AT III], fibrinogen gamma chain [FGG], transthyretin [TTR]) were verified using TBI rat brain tissues and TBI human cerebrospinal fluid (CSF) samples. This study is one of the first to investigate the neuroprotective effects of TTM on the proteome of human and experimental models of TBI, providing an overall landscape of the TBI brain proteome and a scientific foundation for further assessment of candidate molecules associated with TTM for the promotion of reparative strategies post-TBI.

Neurometabolic indicators of mitochondrial dysfunction in repetitive mild traumatic brain injury

Mild traumatic brain injury (mTBI) is a significant national health concern and there is growing evidence that repetitive mTBI (rmTBI) can cause long-term change in brain structure and function. The mitochondrion has been suggested to be involved in the mechanism of TBI. There are noninvasive methods of determining mitochondrial dysfunction through biomarkers and spectroscopy. Mitochondrial dysfunction has been implicated in a variety of neurological consequences secondary to rmTBI through activation of caspases and calpains. The purpose of this review is to examine the mechanism of mitochondrial dysfunction in rmTBI and its downstream effects on neuronal cell death, axonal injury and blood–brain barrier compromise.

Functional and Molecular Correlates after Single and Repeated Rat Closed-Head Concussion: Indices of Vulnerability after Brain Injury

Closed-head concussive injury is one of the most common causes of traumatic brain injury (TBI). Isolated concussions frequently produce acute neurological impairments, and individuals typically recover spontaneously within a short time frame. In contrast, brain injuries resulting from multiple concussions can result in cumulative damage and elevated risk of developing chronic brain pathologies. Increased attention has focused on identification of diagnostic markers that can prognostically serve as indices of brain health after injury, revealing the temporal profile of vulnerability to a second insult. Such markers may demarcate adequate recovery periods before concussed patients can return to required activities. We developed a noninvasive closed-head impact model that captures the hallmark symptoms of concussion in the absence of gross tissue damage. Animals were subjected to single or repeated concussive impact and examined using a battery of neurological, vestibular, sensorimotor, and molecular metrics. A single concussion induced transient, but marked, acute neurological impairment, gait alterations, neuronal death, and increased glial fibrillary acidic protein (GFAP) expression in brain tissue. As expected, repeated concussions exacerbated sensorimotor dysfunction, prolonged gait abnormalities, induced neuroinflammation, and upregulated GFAP and tau. These animals also exhibited chronic functional neurological impairments with sustained astrogliosis and white matter thinning. Acute changes in molecular signatures correlated with behavioral impairments, whereas increased times to regaining consciousness and balance impairments were associated with higher GFAP and neuroinflammation. Overall, behavioral consequences of either single or repeated concussive impact injuries appeared to resolve more quickly than the underlying molecular, metabolic, and neuropathological abnormalities. This observation, which is supported by similar studies in other mTBI models, underscores the critical need to develop more objective prognostic measures for guiding return-to-play decisions.

Endoplasmic reticulum stress implicated in chronic traumatic encephalopathy

OBJECTIVE

Chronic traumatic encephalopathy is a progressive neurodegenerative disease characterized by neurofibrillary tau tangles following repetitive neurotrauma. The underlying mechanism linking traumatic brain injury to chronic traumatic encephalopathy has not been elucidated. The authors investigate the role of endoplasmic reticulum stress as a link between acute neurotrauma and chronic neurodegeneration.

METHODS

The authors used pharmacological, biochemical, and behavioral tools to assess the role of endoplasmic reticulum stress in linking acute repetitive traumatic brain injury to the development of chronic neurodegeneration. Data from the authors' clinically relevant and validated rodent blast model were compared with those obtained from postmortem human chronic traumatic encephalopathy specimens from a National Football League player and World Wrestling Entertainment wrestler.

RESULTS

The results demonstrated strong correlation of endoplasmic reticulum stress activation with subsequent tau hyperphosphorylation. Various endoplasmic reticulum stress markers were increased in human chronic traumatic encephalopathy specimens, and the endoplasmic reticulum stress response was associated with an increase in the tau kinase, glycogen synthase kinase-3β. Docosahexaenoic acid, an endoplasmic reticulum stress inhibitor, improved cognitive performance in the rat model 3 weeks after repetitive blast exposure. The data showed that docosahexaenoic acid administration substantially reduced tau hyperphosphorylation (t = 4.111, p < 0.05), improved cognition (t = 6.532, p < 0.001), and inhibited C/EBP homology protein activation (t = 5.631, p < 0.01). Additionally the data showed, for the first time, that endoplasmic reticulum stress is involved in the pathophysiology of chronic traumatic encephalopathy.

CONCLUSIONS

Docosahexaenoic acid therefore warrants further investigation as a potential therapeutic agent for the prevention of chronic traumatic encephalopathy.

Role of Microvascular Disruption in Brain Damage from Traumatic Brain Injury

Traumatic brain injury (TBI) is acquired from an external force, which can inflict devastating effects to the brain vasculature and neighboring neuronal cells. Disruption of vasculature is a primary effect that can lead to a host of secondary injury cascades. The primary effects of TBI are rapidly occurring while secondary effects can be activated at later time points and may be more amenable to targeting. Primary effects of TBI include diffuse axonal shearing, changes in blood-brain barrier (BBB) permeability, and brain contusions. These mechanical events, especially changes to the BBB, can induce calcium perturbations within brain cells producing secondary effects, which include cellular stress, inflammation, and apoptosis. These secondary effects can be potentially targeted to preserve the tissue surviving the initial impact of TBI. In the past, TBI research had focused on neurons without any regard for glial cells and the cerebrovasculature. Now a greater emphasis is being placed on the vasculature and the neurovascular unit following TBI. A paradigm shift in the importance of the vascular response to injury has opened new avenues of drug-treatment strategies for TBI. However, a connection between the vascular response to TBI and the development of chronic disease has yet to be elucidated. Long-term cognitive deficits are common amongst those sustaining severe or multiple mild TBIs. Understanding the mechanisms of cellular responses following TBI is important to prevent the development of neuropsychiatric symptoms. With appropriate intervention following TBI, the vascular network can perhaps be maintained and the cellular repair process possibly improved to aid in the recovery of cellular homeostasis.

The effect of selective head-neck cooling on physiological and cognitive functions in healthy volunteers

In general, brain temperatures are elevated during physical sporting activities; therefore, reducing brain temperature shortly after a sports-related concussion (SRC) could be a promising intervention technique. The main objective of this study was to examine the effects of head and neck cooling on physiological and cognitive function in normal healthy volunteers. Twelve healthy volunteers underwent two different sessions of combined head and neck cooling, one session with a cold pack and one session with a room temperature pack. Physiological measurements included: systolic/diastolic blood pressure, pulse oximetry, heart rate, and sublingual and tympanic temperature. Cognitive assessment included: processing speed, executive function, and working memory tasks. Physiological measurements were taken pre-, mid- and post-cooling, while cognitive assessments were done before and after cooling. The order of the sessions was randomized. There was a significant decrease in tympanic temperature across both sessions; however more cooling occurred when the cold pack was in the device. There was no significant decrease in sublingual temperature across either session. The observed heart rates, pulse oximetry, systolic and diastolic blood pressure during the sessions were all within range of a normal healthy adult. Cognitive assessment remained stable across each session for both pre- and post-cooling. We propose that optimizing brain temperature management after brain injury using head and neck cooling technology may represent a sensible, practical, and effective strategy to potentially enhance recovery and perhaps minimize the subsequent short and long term consequences from SRC.

The effects of tempol on cyclophosphamide-induced oxidative stress in rat micturition reflexes

We hypothesized that cyclophosphamide- (CYP-) induced cystitis results in oxidative stress and contributes to urinary bladder dysfunction. We determined (1) the expression of oxidative stress markers 3-nitrotyrosine (3-NT), reactive oxygen species (ROS)/reactive nitrogen species (RNS), inflammatory modulators, neuropeptides calcitonin gene-related peptide (CGRP), substance P (Sub P), and adenosine triphosphate (ATP) that contribute to the inflammatory process in the urinary tract and (2) the functional role of oxidative stress in urinary bladder dysfunction with an antioxidant, Tempol, (1 mM in drinking water) combined with conscious cystometry. In CYP-treated (4 hr or 48 hr; 150 mg/kg, i.p.) rats, ROS/RNS and 3-NT significantly (P ≤ 0.01) increased in urinary bladder. CYP treatment increased ATP, Sub P, and CGRP expression in the urinary bladder and cystometric fluid. In CYP-treated rats, Tempol significantly (P ≤ 0.01) increased bladder capacity and reduced voiding frequency compared to CYP-treated rats without Tempol. Tempol significantly (P ≤ 0.01) reduced ATP expression, 3-NT, and ROS/RNS expression in the urinary tract of CYP-treated rats. These studies demonstrate that reducing oxidative stress in CYP-induced cystitis improves urinary bladder function and reduces markers of oxidative stress and inflammation.

Emerging therapies in traumatic brain injury

Despite decades of basic and clinical research, treatments to improve outcomes after traumatic brain injury (TBI) are limited. However, based on the recent recognition of the prevalence of mild TBI, and its potential link to neurodegenerative disease, many new and exciting secondary injury mechanisms have been identified and several new therapies are being evaluated targeting both classic and novel paradigms. This includes a robust increase in both preclinical and clinical investigations. Using a mechanism-based approach the authors define the targets and emerging therapies for TBI. They address putative new therapies for TBI across both the spectrum of injury severity and the continuum of care, from the field to rehabilitation. They discussTBI therapy using 11 categories, namely, (1) excitotoxicity and neuronal death, (2) brain edema, (3) mitochondria and oxidative stress, (4) axonal injury, (5) inflammation, (6) ischemia and cerebral blood flow dysregulation, (7) cognitive enhancement, (8) augmentation of endogenous neuroprotection, (9) cellular therapies, (10) combination therapy, and (11) TBI resuscitation. The current golden age of TBI research represents a special opportunity for the development of breakthroughs in the field.