Time-level relationship for lipid peroxidation and the protective effect of alpha-tocopherol in experimental mild and severe brain injury

Brain Trauma and the Secondary Cascade in Humans: Review of the Potential Role of Vitamins in Reparative Processes and Functional Outcome

An estimated sixty-nine million people sustain a traumatic brain injury each year. Trauma to the brain causes the primary insult and initiates a secondary biochemical cascade as part of the immune and reparative response to injury. The secondary cascade, although a normal physiological response, may also contribute to ongoing neuroinflammation, oxidative stress and axonal injury, continuing in some cases years after the initial insult. In this review, we explain some of the biochemical mechanisms of the secondary cascade and their potential deleterious effects on healthy neurons including secondary cell death. The second part of the review focuses on the role of micronutrients to neural mechanisms and their potential reparative effects with regards to the secondary cascade after brain injury. The biochemical response to injury, hypermetabolism and excessive renal clearance of nutrients after injury increases the demand for most vitamins. Currently, most research in the area has shown positive outcomes of vitamin supplementation after brain injury, although predominantly in animal (murine) models. There is a pressing need for more research in this area with human participants because vitamin supplementation post-trauma is a potential cost-effective adjunct to other clinical and therapeutic treatments. Importantly, traumatic brain injury should be considered a lifelong process and better evaluated across the lifespan of individuals who experience brain injury.

The effect of Vitamins C and E on clinical outcomes of patients with severe traumatic brain injury: A propensity score matching study

Background

The aim of this study was to assess the effect of Vitamins C and E on mortality, intensive care unit (ICU) length of stay, and Glasgow Outcome Scale-Extended (GOS-E) score of traumatic brain injury (TBI) patients.

Methods

Using data from records of patients in a retrospective cohort study, we included 1321 TBI patients, 269 treated and 1052 untreated, aged over 18 years with information on exposure (i.e., Vitamins C and E) and confounders. Age, Glasgow Coma Scale, pupil status, Rotterdam classification, blood sugar, blood pressure, international normalized ratio, and comorbidity of patients were considered as the confounding factors. Endpoints were GOS-E on follow-up, mortality, and ICU length of stay. Propensity score matching was performed to adjust the confounders.

Results

Based on the average treatment effect estimates, the use of Vitamins C and E reduced the risk of mortality (risk difference [RD]: -0.07; 95% confidence interval [CI]: -0.14--0.003) and reduced the length of ICU stay (RD -1.77 95% CI:-3.71-0.16). Furthermore, our results showed that GOS-E was improved significantly (RD: 0.09, 95% CI : 0.03-0.16).

Conclusion

Our study suggests that using Vitamins C and E could decrease mortality and length of ICU stay and improve the GOS-E score and functions of the patients with severe TBI. As they are safe and inexpensive medications, they can be used in routine practice in ICUs to improve the outcomes of TBI patients.

Oxidative Stress in Traumatic Brain Injury

Traumatic Brain Injury (TBI) remains a major cause of disability worldwide. It involves a complex neurometabolic cascade, including oxidative stress. The products of this manuscript is examining the underlying pathophysiological mechanism, including reactive oxygen species (ROS) and reactive nitrogen species (RNS). This process in turn leads to secondary injury cascade, which includes lipid peroxidation products. These reactions ultimately play a key role in chronic inflammation and synaptic dysfunction in a synergistic fashion. Although there are no FDA approved antioxidant therapy for TBI, there is a number of antioxidant therapies that have been tested and include free radical scavengers, activators of antioxidant systems, inhibitors of free radical generating enzymes, and antioxidant enzymes. Antioxidant therapies have led to cognitive and functional recovery post TBI, and they offer a promising treatment option for patients recovering from TBI. Current major challenges in treatment of TBI symptoms include heterogenous nature of injury, as well as access to timely treatment post injury. The inherent benefits of antioxidant therapies include minimally reported side effects, and relative ease of use in the clinical setting. The current review also provides a highlight of the more studied anti-oxidant regimen with applicability for TBI treatment with potential use in the real clinical setting.

Serum vitamin E level and functional prognosis after traumatic brain injury with intracranial injury: A multicenter prospective study

Background

Traumatic brain injury (TBI) is a major public health problem with high mortality and disability. Vitamin E, one of the antioxidants for treatment of TBI, has not been sufficiently evaluated for predicting prognosis of TBI. This study aimed to evaluate the prognostic value of vitamin E on functional outcomes of TBI patients with intracranial injury.

Methods

A multi-center prospective cohort study was conducted in five university hospitals between 2018 and 2020. Adult TBI patients who visited the emergency department (ED) with intracranial hemorrhage or diffuse axonal injury confirmed by radiological examination were eligible. Serum vitamin E levels (mg/dL) were categorized into 4 groups: low (0.0–5.4), low-normal (5.5–10.9), high-normal (11.0–16.9), and high (17.0–). Study outcomes were set as 1- and 6-month disability (Glasgow outcome scale (GOS) 1–4). Multilevel logistic regression analysis was conducted to calculate the adjusted odds ratios (AORs) of vitamin E for related outcomes.

Results

Among 550 eligible TBI patients with intracranial injury, the median (IQR) of serum vitamin E was 10.0 (8.0–12.3) mg/dL; 204/550 (37.1%) had 1-month disability and 197/544 (36.1%) had 6-month disability of GOS 1–4. Compared with the high-normal group, the odds of 1-month disability and 6-month disability increased in the low and low-normal group (AORs (95% CIs): 3.66 (1.62–8.27) and 2.60 (1.15–5.85) for the low group and 1.63 (1.08–2.48) and 1.60 (1.04–2.43) for the low-normal group, respectively).

Conclusion

Low serum vitamin E level was associated with poor prognosis at 1 and 6 months after TBI with intracranial injury.

Oxidative stress and mitochondrial dysfunction following traumatic brain injury: From mechanistic view to targeted therapeutic opportunities

Traumatic brain injury (TBI) is one of the most prevalent causes of permanent physical and cognitive disabilities. TBI pathology results from primary insults and a multi-mechanistic biochemical process, termed as secondary brain injury. Currently, there are no pharmacological agents for definitive treatment of patients with TBI. This article is presented with the purpose of reviewing molecular mechanisms of TBI pathology, as well as potential strategies and agents against pathological pathways. In this review article, materials were obtained by searching PubMed, Scopus, Elsevier, Web of Science, and Google Scholar. This search was considered without time limitation. Evidence indicates that oxidative stress and mitochondrial dysfunction are two key mediators of the secondary injury cascade in TBI pathology. TBI-induced oxidative damage results in the structural and functional impairments of cellular and subcellular components, such as mitochondria. Impairments of mitochondrial electron transfer chain and mitochondrial membrane potential result in a vicious cycle of free radical formation and cell apoptosis. The results of some preclinical and clinical studies, evaluating mitochondria-targeted therapies, such as mitochondria-targeted antioxidants and compounds with pleiotropic effects after TBI, are promising. As a proposed strategy in recent years, mitochondria-targeted multipotential therapy is a new hope, waiting to be confirmed. Moreover, based on the available findings, biologics, such as stem cell-based therapy and transplantation of mitochondria are novel potential strategies for the treatment of TBI; however, more studies are needed to clearly confirm the safety and efficacy of these strategies.

Antioxidant therapies in traumatic brain injury

Oxidative stress plays a crucial role in traumatic brain injury (TBI) pathogenesis. Reactive oxygen species (ROS) and reactive nitrogen species (RNS) formed in excess after TBI synergistically contribute to secondary brain damage together with lipid peroxidation products (reactive aldehydes) and inflammatory mediators. Furthermore, oxidative stress, endoplasmic reticulum stress and inflammation potentiate each other. Following TBI, excessive oxidative stress overloads the endogenous cellular antioxidant system leading to cell death. To combat oxidative stress, several antioxidant therapies were tested in preclinical animal models of TBI. These include free radical scavengers, activators of antioxidant systems, Inhibitors of free radical generating enzymes and antioxidant enzymes. Many of these therapies showed promising outcomes including reduced edema, blood-brain barrier (BBB) protection, smaller contusion volume, and less inflammation. In addition, many antioxidant therapies also promoted better sensory, motor, and cognitive functional recovery after TBI. Overall, preventing oxidative stress is a viable therapeutic option to minimize the secondary damage and to improve the quality of life after TBI.

Protective effect of thymoquinone in preventing trauma-related damage: an experimental study

BACKGROUND

Secondary injury is a potentially modifiable factor of outcome in traumatic brain injury. This study aimed to investigate thymoquinone's effects on trauma-induced neuronal damage.

METHODS

Eighteen adult female Sprague-Dawley rats were assigned into three groups following ketamine and xylazine anaesthesia (n = 6): Control, Trauma, Trauma + Thymoquinone. First dose of thymoquinone was administered three hours after the trauma.

RESULTS

The trauma group showed significant oedema, vascular congestion, and ischaemia. Also, caspase-3 activity and malondialdehyde content of brain tissue was significantly increased, and Na,K-ATPase activity and glutathione levels were significantly reduced. Thymoquinone significantly reduced oedema, vascular congestion, ischaemia, and caspase-3 activity compared with the trauma group. While Na,K-ATPase activity and glutathione levels was similar to the Control group, malondialdehyde content was similar to the trauma group.

CONCLUSIONS

This study showed that low dose thymoquinone exhibited a neuroprotective effect following severe traumatic brain injury, if administered within three hours of injury. Similar levels of glutathione and malondialdehyde suggest no antioxidant effect. Significant reduction in oedema and ischaemia in the neuron cells and partially preserved activity of Na,K-ATPase suggest that thymoquinone protects mitochondrial functions and energy levels of the neuronal cells following severe traumatic brain injury.

Lipid Peroxidation and Antioxidant Consumption as Early Markers of Neurosurgery-Related Brain Injury in Children

BACKGROUND AND AIMS

Lipid peroxidation represents a marker of secondary brain injury both in traumatic and in non-traumatic conditions-as in major neurosurgical procedures-eventually leading to brain edema amplification and further brain damage. Malondialdehyde (MDA), a lipid peroxidation marker, and ascorbate, a marker of antioxidant status, can represent early indicators of this process within the cerebrospinal fluid (CSF). We hypothesized that changes in cerebral lipid peroxidation can be measured ex vivo following neurosurgery in children.

METHODS

Thirty-six children (M:F = 19/17, median age 32.9 months; IQR 17.6-74.6) undergoing neurosurgery for brain tumor removal were admitted to the pediatric intensive care unit (PICU) in the postoperative period with an indwelling intraventricular catheter for intracranial pressure monitoring and CSF drainage. Plasma and CSF samples were obtained for serial measurement of MDA, ascorbate, and cytokines.

RESULTS

An early brain-limited increase in lipid peroxidation was measured, with a significant increase from baseline of MDA in CSF (p = 0.007) but not in plasma. In parallel, ascorbate in CSF decreased (p = 0.05). Systemic inflammatory response following brain surgery was evidenced by plasma IL-6/IL-8 increase (p 0.0022 and 0.0106, respectively). No correlation was found between oxidative response and tumor site or histology (according to World Health Organization grading). Similarly, lipid peroxidation was unrelated to the length of surgery (mean 321 ± 73 min), or intraoperative blood loss (mean 20.9 ± 16.8% of preoperative volemia, 44% given hemotransfusions). Median PICU stay was 3.5 days (IQL range 2-5.5 d.), and postoperative ventilation need was 24 h (IQL range 20-61.5 h). The elevation in postoperative MDA in CSF compared with preoperative values correlated significantly with postoperative ventilation need (P = 0.05, r² 0168), while no difference in PICU stay was recorded.

CONCLUSIONS

Our results indicate that lipid peroxidation increases consistently following brain surgery, and it is accompanied by a decrease in antioxidant defences; intraventricular catheterization offers a unique chance of oxidative process monitoring. Further studies are needed to evaluate whether monitoring post-neurosurgical oxidative stress in CSF is of prognostic utility.

Modulating neuroinflammation and oxidative stress to prevent epilepsy and improve outcomes after traumatic brain injury

Traumatic brain injury (TBI) is a leading cause of death and disability in young adults worldwide. TBI survival is associated with persistent neuropsychiatric and neurological impairments, including posttraumatic epilepsy (PTE). To date, no pharmaceutical treatment has been found to prevent PTE or ameliorate neurological/neuropsychiatric deficits after TBI. Brain trauma results in immediate mechanical damage to brain cells and blood vessels that may never be fully restored given the limited regenerative capacity of brain tissue. This primary insult unleashes cascades of events, prominently including neuroinflammation and massive oxidative stress that evolve over time, expanding the brain injury, but also clearing cellular debris and establishing homeostasis in the region of damage. Accumulating evidence suggests that oxidative stress and neuroinflammatory sequelae of TBI contribute to posttraumatic epileptogenesis. This review will focus on possible roles of reactive oxygen species (ROS), their interactions with neuroinflammation in posttraumatic epileptogenesis, and emerging therapeutic strategies after TBI. We propose that inhibitors of the professional ROS-generating enzymes, the NADPH oxygenases and myeloperoxidase alone, or combined with selective inhibition of cyclooxygenase mediated signaling may have promise for the treatment or prevention of PTE and other sequelae of TBI. This article is part of the special issue entitled 'New Epilepsy Therapies for the 21st Century - From Antiseizure Drugs to Prevention, Modification and Cure of Epilepsy'.

Antioxidant Therapies in Traumatic Brain Injury

Due to a multiplicity of causes provoking traumatic brain injury (TBI), TBI is a highly heterogeneous pathology, characterized by high mortality and disability rates. TBI is an acute neurodegenerative event, potentially and unpredictably evolving into sub-chronic and chronic neurodegenerative events, with transient or permanent neurologic, cognitive, and motor deficits, for which no valid standardized therapies are available. A vast body of literature demonstrates that TBI-induced oxidative/nitrosative stress is involved in the development of both acute and chronic neurodegenerative disorders. Cellular defenses against this phenomenon are largely dependent on low molecular weight antioxidants, most of which are consumed with diet or as nutraceutical supplements. A large number of studies have evaluated the efficacy of antioxidant administration to decrease TBI-associated damage in various animal TBI models and in a limited number of clinical trials. Points of weakness of preclinical studies are represented by the large variability in the TBI model adopted, in the antioxidant tested, in the timing, dosages, and routes of administration used, and in the variety of molecular and/or neurocognitive parameters evaluated. The analysis of the very few clinical studies does not allow strong conclusions to be drawn on the real effectiveness of antioxidant administration to TBI patients. Standardizing TBI models and different experimental conditions, as well as testing the efficacy of administration of a cocktail of antioxidants rather than only one, should be mandatory. According to some promising clinical results, it appears that sports-related concussion is probably the best type of TBI to test the benefits of antioxidant administration.

Therapeutic Hypothermia Protects Against Heat Stroke-Induced Arterial Hypotension via Promoting Left Ventricular Performance in Rats

We aimed to ascertain whether therapeutic hypothermia (TH) acts as cardioprotective management for heat stroke (HS). Adult male rats under general anesthesia were exposed to whole-body heating (43°C for 70 min) to induce HS. Rats with HS displayed hyperthermia (core body temperature 42°C vs. 36°C); hypotension (30 mmHg vs. 90 mmHg mean arterial blood pressure); suppressed left ventricular (LV) performance (stroke volume 52 μl/min vs. 125 μl/min), ejection fraction (0.29% vs. 0.69%), relaxation factor (72 ms vs. 12 ms), and arterial elastance (0.31 mmHg/ μl vs. 10 mmHg/ μl); increased myocardial injury markers (e.g., creatine kinase-MB: 86 U/L vs. 24 U/L, cardiac troponin I: 3.08 ng/ml vs. 0.57 ng/ml); increased myocardial oxidative stress markers (e.g., malondialdehyde: 6.52 nmol/mg vs. 1.06 nmol/mg, thiobarbituric acid-reactive substances: 29 nmol/g vs. 2 nmol/g); decreased myocardial antioxidants (e.g., superoxide dismutase: 6 unit/mg vs. 17 unit/mg, reduced glutathione: 0.64 nmol/mg vs. 2.53 nmol/mg); increased myocardial proinflammatory cytokines (e.g., tumor necrosis factor-α 3200 pg/ml vs. 1000 pg/ml, interleukin-6: 668 pg/ml vs. 102 pg/ml); and increased cardiac damage scores (2.2 vs. 0.3). TH therapy significantly reversed the following conditions: HS-induced hyperthermia (37.5°C core body temperature), hypotension (71 mmHg), suppressed LV performance (stroke volume: 97 μl/min, ejection fraction: 0.65%, relaxation factor: 39 ms, and arterial elastance: 0.99 mmHg/μl), increased myocardial injury markers (e.g., creatine kinase-MB: 37 U/L, cardiac troponin I: 1.06 ng/ml), increased myocardial oxidative stress markers (e.g., malondialdehyde: 2.68 nmol/mg, thiobarbituric acid-reactive substances: 12.3 nmol/g), decreased myocardial antioxidants (e.g., superoxide dismutase: 13.3 unit/mg, reduced glutathione: 2.71 mmol/mg), increased myocardial proinflammatory cytokines (e.g., tumor necrosis factor-α 1500 pg/ml, interleukin-6: 108 ng/ml); and increased cardiac damage scores (0.9). We thus conclude that TH protects against HS-induced arterial hypotension by promoting LV performance in rats. These results add to the literature regarding the use of TH as cardioprotective management for HS.

Salidroside pretreatment protects against myocardial injury induced by heat stroke in mice

Objective

To explore the protective effects and mechanisms of salidroside on myocardial injury induced by heat stroke (HS) in mice.

Methods

We pretreated mice with salidroside for 1 week and then established an HS model by exposure to 41.2°C for 1 hour. We then examined the effects of salidroside on survival. We also assessed the severity of cardiac injury by pathology, and analyzed changes in levels of myocardial injury markers, inflammatory cytokines, and oxidative stress.

Results

Salidroside pretreatment significantly reduced HS-induced mortality and improved thermoregulatory function. Salidroside also provided significant protection against HS-induced myocardial damage, and decreased the expression levels of cardiac troponin I, creatine kinase-MB, and lactate dehydrogenase. Moreover, salidroside attenuated HS-induced changes in the inflammation markers tumor necrosis factor-α, interleukin (IL)-6, and IL-10, and down-regulated the oxidative stress response indicated by thiobarbituric acid reactant substances, malondialdehyde, reduced glutathione, and superoxide dismutase.

Conclusions

Salidroside pretreatment protected against HS-induced myocardial damage, potentially via a mechanism involving anti-inflammatory and anti-oxidative effects.

Calycosin-7-O-β-D-glucoside reduces myocardial injury in heat stroke rats

BACKGROUND/PURPOSE

Calycosin-7-O-β-D-glucoside (CG), a calycosin derivative compound derived from Astragali Radix, has protective effect against ischemia/reperfusion injury as well as bacterial endotoxin-induced vascular cell injury. In the present study, we ascertained whether CG could reduce myocardial injury in heatstroke rats.

METHODS

Heat stroke was induced by exposing anaesthetized rats to heat stress (43 °C for 70 min). Rats were given an i.p. dose of CG (26.8 mg/ml/kg) or vehicle solution (ml/kg) 15 min before the start of heat stress and immediately after termination of heat stress. Left ventricular performance, myocardial injury markers in the blood, and myocardial damage scores were assessed in heat stroke rats treated with or without CG. Additionally, cardiac levels of oxidative stress and inflammatory status were estimated simultaneously.

RESULTS

At the time point of heat stroke onset, compared with normothermic controls, group rats with vehicle solution had significantly decreased survival rate, increased hyperthermia, decreased left ventricular stress markers, and increased cardiac damage scores. Compared with group rats with vehicle solution, group rats with CG had significantly improved survival rate, decreased hyperthermia, decreased cardiac ischemic, inflammatory, and oxidative damage.

CONCLUSION

We thus conclude that myocardial injury can be a pressing need for the design of diagnostic and therapeutic modalities for heat stroke. In particular, our data indicate that CG protects against heat stroke in rats by mitigating myocardial injury.

Effect of lithocholic acid on biologically active α,β-unsaturated aldehydes induced by H2O2 in glioma mitochondria for use in glioma treatment

Lithocholic acid (LCA) is known to kill glioma cells while sparing normal neuronal cells. However, the anti-glioma mechanism of LCA is unclear at present. Although malondialdehyde (MDA) is not specific to detect tumors, biologically active α,β-unsaturated aldehydes can be used to detect the outcome of gliomas, especially the mitochondria, as a research tool. The purpose of this research was to determine the optimum conditions for a lipid peroxidation model, according to changes in the aldehydes formed from the reaction between 2-thiobarbituric acid and biologically active α,β-unsaturated aldehydes. Experimental methods and procedures were successfully established for a model of lipid peroxidation induced by H₂O₂ in glioma mitochondria for glioma treatment and optimum conditions for LCA treatment were determined. The optimal conditions for the model were a glioma mitochondrial concentration of 1.5 mg/ml, H₂O₂ concentration of 0.3 mg/ml, duration of action of 30 min, and addition of 4.0 ml of 46 mM thiobarbituric acid. The effect of LCA, as determined by changes in the UV peaks at 450, 495, and 532 nm, was optimal at a concentration of 100 µM, a duration of action of 15 min, and in an acidic microenvironment. The study concluded that a suitable concentration of LCA has anti-glioma effects as determined by the effect on changes in the UV peaks at 450, 495 and 532 nm and the mitochondrial model developed should be conducive to further in-depth research.

Melatonin provides protection against heat stroke-induced myocardial injury in male rats

OBJECTIVES

This study aimed to investigate the cardioprotective effects of melatonin on heat stroke (HS) induced acute myocardial infarction in rats and to explore the underlying mechanisms.

METHODS

Myocardial injury was induced by subjecting the anaesthetized rats to a high ambient temperature of 43°C for 70 min. Such a high ambient temperature caused hyperthermia, hypotension and myocardial injury in rats. Rats were treated with melatonin (3 mg/kg) intravenously one hour before and followed by an additional dose immediately after heat stress.

KEY FINDINGS

At the onset of HS, animals displayed myocardial injury evidenced by increased levels of cardiac damage indicators (e.g. total lactate dehydrogenase, cardiac troponin I and creatine kinase-MB), increased cardiac damage scores and suppressed left ventricular performance. Animals with HS also had increased cardiac oxidative stress evidenced by increased levels of lipid peroxidation (e.g. increased thiobarbituric acid reactive substances) and decreased levels of antioxidant enzymes (e.g. superoxide dismutase, catalase and reduced glutathione) and activated inflammation (e.g. increased levels of interleukin-6 and tumour necrosis factor-α). Pretreatment with melatonin significantly reversed the HS-induced myocardial injury, cardiac oxidative stress and cardiac inflammation.

CONCLUSIONS

Melatonin may protect against HS-induced myocardial injury in male rats by mitigating oxidative stress and inflammation.

Vitamins and nutrients as primary treatments in experimental brain injury: Clinical implications for nutraceutical therapies

With the numerous failures of pharmaceuticals to treat traumatic brain injury in humans, more researchers have become interested in combination therapies. This is largely due to the multimodal nature of damage from injury, which causes excitotoxicity, oxidative stress, edema, neuroinflammation and cell death. Polydrug treatments have the potential to target multiple aspects of the secondary injury cascade, while many previous therapies focused on one particular aspect. Of specific note are vitamins, minerals and nutrients that can be utilized to supplement other therapies. Many of these have low toxicity, are already FDA approved and have minimal interactions with other drugs, making them attractive targets for therapeutics. Over the past 20 years, interest in supplementation and supraphysiologic dosing of nutrients for brain injury has increased and indeed many vitamins and nutrients now have a considerable body of the literature backing their use. Here, we review several of the prominent therapies in the category of nutraceutical treatment for brain injury in experimental models, including vitamins (B2, B3, B6, B9, C, D, E), herbs and traditional medicines (ginseng, Gingko biloba), flavonoids, and other nutrients (magnesium, zinc, carnitine, omega-3 fatty acids). While there is still much work to be done, several of these have strong potential for clinical therapies, particularly with regard to polydrug regimens. This article is part of a Special Issue entitled SI:Brain injury and recovery.

Current status of fluid biomarkers in mild traumatic brain injury

Mild traumatic brain injury (mTBI) affects millions of people annually and is difficult to diagnose. Mild injury is insensitive to conventional imaging techniques and diagnoses are often made using subjective criteria such as self-reported symptoms. Many people who sustain a mTBI develop persistent post-concussive symptoms. Athletes and military personnel are at great risk for repeat injury which can result in second impact syndrome or chronic traumatic encephalopathy. An objective and quantifiable measure, such as a serum biomarker, is needed to aid in mTBI diagnosis, prognosis, return to play/duty assessments, and would further elucidate mTBI pathophysiology. The majority of TBI biomarker research focuses on severe TBI with few studies specific to mild injury. Most studies use a hypothesis-driven approach, screening biofluids for markers known to be associated with TBI pathophysiology. This approach has yielded limited success in identifying markers that can be used clinically, additional candidate biomarkers are needed. Innovative and unbiased methods such as proteomics, microRNA arrays, urinary screens, autoantibody identification and phage display would complement more traditional approaches to aid in the discovery of novel mTBI biomarkers.

Anti-apoptotic and anti-oxidative roles of quercetin after traumatic brain injury

Experimental studies have demonstrated significant secondary damage (including cell apoptosis, blood-brain barrier disruption, inflammatory responses, excitotoxic damage, and free radical production) after traumatic brain injury (TBI). Quercetin is a natural flavonoid found in high quantities in fruits and vegetables, and may be a potential antioxidant and free radical scavenger. The purpose of this study was to determine the effects of quercetin on TBI-induced upregulation of oxidative stress, inflammation, and apoptosis in adult Sprague-Dawley rats. Animals were subjected to Feeney's weight-drop injury, thus inducing the parietal contusion brain injury model. Quercetin was administered (30 mg/kg intraperitoneal injection) 0, 24, 48, and 72 h after TBI. Quercetin reduced cognitive deficits, the number of TUNEL- and ED-1-positive cells, the protein expressions of Bax and cleaved-caspase-3 proteins, and the levels of TBARS and proinflammatory cytokines, and increased the activity of antioxidant enzymes (GSH-Px, SOD, and CAT) at 1 week after TBI. Our results suggest that in TBI rats, quercetin improves cognitive function owing to its neuroprotective action via the inhibition of oxidative stress, leading to a reduced inflammatory response, thereby reducing neuronal death.

Traumatic brain injury in vivo and in vitro contributes to cerebral vascular dysfunction through impaired gap junction communication between vascular smooth muscle cells

Gap junctions (GJs) contribute to cerebral vasodilation, vasoconstriction, and, perhaps, to vascular compensatory mechanisms, such as autoregulation. To explore the effects of traumatic brain injury (TBI) on vascular GJ communication, we assessed GJ coupling in A7r5 vascular smooth muscle (VSM) cells subjected to rapid stretch injury (RSI) in vitro and VSM in middle cerebral arteries (MCAs) harvested from rats subjected to fluid percussion TBI in vivo. Intercellular communication was evaluated by measuring fluorescence recovery after photobleaching (FRAP). In VSM cells in vitro, FRAP increased significantly (p<0.05 vs. sham RSI) after mild RSI, but decreased significantly (p<0.05 vs. sham RSI) after moderate or severe RSI. FRAP decreased significantly (p<0.05 vs. sham RSI) 30 min and 2 h, but increased significantly (p<0.05 vs. sham RSI) 24 h after RSI. In MCAs harvested from rats 30 min after moderate TBI in vivo, FRAP was reduced significantly (p<0.05), compared to MCAs from rats after sham TBI. In VSM cells in vitro, pretreatment with the peroxynitrite (ONOO(-)) scavenger, 5,10,15,20-tetrakis(4-sulfonatophenyl)prophyrinato iron[III], prevented RSI-induced reductions in FRAP. In isolated MCAs from rats treated with the ONOO(-) scavenger, penicillamine, GJ coupling was not impaired by fluid percussion TBI. In addition, penicillamine treatment improved vasodilatory responses to reduced intravascular pressure in MCAs harvested from rats subjected to moderate fluid percussion TBI. These results indicate that TBI reduced GJ coupling in VSM cells in vitro and in vivo through mechanisms related to generation of the potent oxidant, ONOO(-).

Perspectives on molecular biomarkers of oxidative stress and antioxidant strategies in traumatic brain injury

Traumatic brain injury (TBI) is frequently associated with abnormal blood-brain barrier function, resulting in the release of factors that can be used as molecular biomarkers of TBI, among them GFAP, UCH-L1, S100B, and NSE. Although many experimental studies have been conducted, clinical consolidation of these biomarkers is still needed to increase the predictive power and reduce the poor outcome of TBI. Interestingly, several of these TBI biomarkers are oxidatively modified to carbonyl groups, indicating that markers of oxidative stress could be of predictive value for the selection of therapeutic strategies. Some drugs such as corticosteroids and progesterone have already been investigated in TBI neuroprotection but failed to demonstrate clinical applicability in advanced phases of the studies. Dietary antioxidants, such as curcumin, resveratrol, and sulforaphane, have been shown to attenuate TBI-induced damage in preclinical studies. These dietary antioxidants can increase antioxidant defenses via transcriptional activation of NRF2 and are also known as carbonyl scavengers, two potential mechanisms for neuroprotection. This paper reviews the relevance of redox biology in TBI, highlighting perspectives for future studies.

Oxidative stress, DNA damage, and the telomeric complex as therapeutic targets in acute neurodegeneration

Oxidative stress has been identified as an important contributor to neurodegeneration associated with acute CNS injuries and diseases such as spinal cord injury (SCI), traumatic brain injury (TBI), and ischemic stroke. In this review, we briefly detail the damaging effects of oxidative stress (lipid peroxidation, protein oxidation, etc.) with a particular emphasis on DNA damage. Evidence for DNA damage in acute CNS injuries is presented along with its downstream effects on neuronal viability. In particular, unchecked oxidative DNA damage initiates a series of signaling events (e.g. activation of p53 and PARP-1, cell cycle re-activation) which have been shown to promote neuronal loss following CNS injury. These findings suggest that preventing DNA damage might be an effective way to promote neuronal survival and enhance neurological recovery in these conditions. Finally, we identify the telomere and telomere-associated proteins (e.g. telomerase) as novel therapeutic targets in the treatment of neurodegeneration due to their ability to modulate the neuronal response to both oxidative stress and DNA damage.

Stuck at the bench: Potential natural neuroprotective compounds for concussion

Background:

While numerous laboratory studies have searched for neuroprotective treatment approaches to traumatic brain injury, no therapies have successfully translated from the bench to the bedside. Concussion is a unique form of brain injury, in that the current mainstay of treatment focuses on both physical and cognitive rest. Treatments for concussion are lacking. The concept of neuro-prophylactic compounds or supplements is also an intriguing one, especially as we are learning more about the relationship of numerous sub-concussive blows and/or repetitive concussive impacts and the development of chronic neurodegenerative disease. The use of dietary supplements and herbal remedies has become more common place.

Methods:

A literature search was conducted with the objective of identifying and reviewing the pre-clinical and clinical studies investigating the neuroprotective properties of a few of the more widely known compounds and supplements.

Results:

There are an abundance of pre-clinical studies demonstrating the neuroprotective properties of a variety of these compounds and we review some of those here. While there are an increasing number of well-designed studies investigating the therapeutic potential of these nutraceutical preparations, the clinical evidence is still fairly thin.

Conclusion:

There are encouraging results from laboratory studies demonstrating the multi-mechanistic neuroprotective properties of many naturally occurring compounds. Similarly, there are some intriguing clinical observational studies that potentially suggest both acute and chronic neuroprotective effects. Thus, there is a need for future trials exploring the potential therapeutic benefits of these compounds in the treatment of traumatic brain injury, particularly concussion.

Pyridoxine administration improves behavioral and anatomical outcome after unilateral contusion injury in the rat

The purpose of this project was to evaluate the preclinical efficacy of pyridoxine, or vitamin B(6). Rats received a 3.0 mm unilateral controlled cortical impact (CCI) injury of the sensorimotor cortex or sham surgery. Treatment with vitamin B(6) (600 or 300 mg/kg IP) or vehicle was administered at 30 min and 24 h post-CCI. Somatosensory dysfunction was evaluated with the vibrissae-forelimb placing and bilateral tactile adhesive removal tests. Sensorimotor dysfunction was evaluated with the locomotor placing and the forelimb asymmetry tests. On the forelimb asymmetry test both treatment groups displayed no asymmetry bias on any of the testing days post-CCI and were statistically no different than the shams. Both vitamin B(6) groups displayed a significant improvement in behavioral performance on the locomotor placing test compared to the vehicle-treated group. Administration of 600 mg/kg also significantly reduced tactile adhesive removal latencies on days 2, 4, 6, and 12 post-CCI. Both treatment groups were improved in their rate of recovery post-CCI on the vibrissae-forelimb placing test, but only the recovery seen in the 600-mg/kg group was significantly improved compared to vehicle. Finally, the 600-mg/kg dose resulted in significant cortical sparing compared to the vehicle-treated group. In general, the effects of vitamin B(6) on recovery of function were dose-dependent, with the 600-mg/kg dose consistently showing greater recovery than the 300-mg/kg dose. More experimental analyses are warranted to evaluate the potential preclinical efficacy and mechanistic action of vitamin B(6).

Relationship between markers of lipid peroxidation, thiol oxidation and Glasgow coma scale scores of moderate head injury patients in the 7 day post-traumatic period

OBJECTIVE

Epidemiologic works reveal that moderate head injury (MHI) is more frequent and a substantial number of these patients develop complications resulting in neurological disabilities. Reactive oxygen species (ROS) play a major role in post-traumatic neuronal damage following traumatic head injury. Thus, the current study analysed the post-traumatic changes in the erythrocyte markers of oxidative damage and the relationship between these parameters and Glasgow coma scale (GCS) scores of MHI patients during the 7 day study period.

METHODS

Peripheral venous blood samples were taken at the time of hospital admission (d1 of injury) and on d7 from 25 MHI patients (admission GCS score > 8). These were compared with samples from 25 healthy individuals (normal controls, NC). GCS scores were recorded at the same time points of the study period. Erythrocyte lipid peroxidation (LP) and thiol oxidation levels were estimated and compared with that of NC. The relationship between GCS scores and erythrocyte markers were also studied.

RESULTS

Erythrocyte thiobarbituric acid reactive substance (TBARS) levels reflecting lipid peroxidative damage remained significantly elevated at both time points of the study period in MHI patients as compared to NC (p < 0.001 ). There was a significant decrease in the level of nonprotein thiols in MHI patients as compared to NC (p < 0.01) at the same time points of the study. However, on d7 there were no further significant changes in the markers of oxidative damage in MHI patients as compared to on d1.

CONCLUSION

These findings suggest that a condition of oxidative stress occurs during the entire post-traumatic period in MHI patients and the utility of markers of oxidative damage in the prognosis of head injury needs to be addressed in further works.

Neuroprotective effects of high-dose vs low-dose melatonin after blunt sciatic nerve injury

INTRODUCTION

Melatonin, the secretory product of the pineal gland, has potent antioxidant properties. The aim of this study was to compare the effects of low-dose (10 mg/kg) vs high-dose (50 mg/kg) melatonin on early lipid peroxidation levels and ultrastructural changes in experimental blunt sciatic nerve injury (SNI). We believe this to be the first study to assess the dose-dependent neuroprotective effects of melatonin after a blunt peripheral nerve injury.

MATERIALS AND METHODS

Rats were randomly allocated into 5 groups of 10 animals each. The SNI only rats underwent a nerve injury procedure. The SNI plus vehicle group received SNI and intraperitoneal injection of vehicle (diluted ethanol) as a placebo. The SNI plus low-dose or high-dose melatonin groups received intraperitoneal melatonin at doses of 10 mg/kg or 50 mg/kg, respectively. Controls had no operation, melatonin or vehicle injection. SNI was induced by clamping the sciatic nerve at the upper border of the quadratus femoris for 2 min.

RESULTS

Sciatic nerve samples were harvested 6 h after nerve injury and processed for biochemical and ultrastructural analysis. Trauma increased the lipid peroxidation of the sciatic nerve by 3.6-fold (153.85 +/- 18.73 in SNI only vs 41.73 +/- 2.23 in control rats, P < 0.01). Low (P = 0.02) and high (P < 0.01) doses of melatonin attenuated the nerve lipid peroxidation by 25% and 57.25%, respectively (65.76 +/- 2.47 in high-dose vs 115.08 +/- 7.03 in low-dose melatonin groups).

DISCUSSION

Although low-dose melatonin reduced trauma-induced myelin breakdown and axonal changes in the sciatic nerve, high-dose melatonin almost entirely neutralized any ultrastructural changes.

CONCLUSION

Our results suggest that melatonin, especially at a dose of 50 mg/kg, has a potent neuroprotective effect and can preserve peripheral neural fibers from lipid peroxidative damage after blunt trauma. With further investigations, we hope that these data may prove useful to clinicians who treat patients with nerve injuries.

Poly(ADP-ribose) polymerase-1 and its clinical applications in brain injury

Traumatic brain injury (TBI) is a devastating occurrence that may result in short- and long-term complications. Oxidative stress (an imbalance between oxidants and antioxidants) plays a critical role in the development of secondary injuries following TBI and, consequently, in patient outcomes. Secondary injuries resulting from oxidative stress produce DNA strand breaks that activate poly(adenosine diphosphate [ADP]-ribose) polymerase-1 (PARP-1) and produce another level of injury. PARP-1 functions as a DNA-damage sensor and signaling molecule. In response to the severe DNA damage after brain injury, PARP-1 becomes overactivated and depletes the cells' energy sources, which leads to cellular and neuronal death. Recently, PARP-1 inhibition has been studied in various animal models of brain injury with promising results. TBI treatments based on PARP-1 inhibition in humans are far from the clinical arena, although descriptive studies of PARP-1 activation in humans are beginning to emerge. Nurses should become involved in this area of collaborative research in human response to brain injury by helping design and implement safe and meaningful clinical trials.

Attenuation of microtubule associated protein-2 degradation after mild head injury by mexiletine and calpain-2 inhibitor

The objective of the study was to address the early effects of mild, closed, head injuries on neuronal stability and the prevention of microtubule-associated protein-2 (MAP-2) degradation by mexiletine and calpain-2 inhibitor. Twenty-four rats were divided into four groups: control group (1); trauma group without treatment (2); mexiletine-pretreated and subjected to trauma group (3); trauma subjected and then calpain-2 inhibitor received group (4). All animals were subjected to mild, closed, head trauma. Frontal lobes were removed and processed for staining and immunofluorescent labelling of MAP-2 cytoskeletal proteins, which were evaluated by confocal microscopy in serial optical sections showing the three dimensional cytoarchitecture of affected areas. MAP-2 decoration in almost all neurons obtained from traumatized brain regions drastically diminished, while minute filamentous and granular profiles in axons and/or dendrites were retained together implying a massive degradation/depolymerization of microtubules. In contrast, in mexiletine-pretreated animals, MAP-2 positivity in axonal and perikaryonal profiles was fairly retained, which clearly depicts the protective role of mexiletine after trauma. Compared with mexiletine-pretreated group, calpain-2 inhibitor treated group displayed a less well-preserved MAP-2 expression. Mexiletine can prevent cytoskeletal structure and protein degradation after mild head trauma. Calpain-2 inhibitor prevents protein degradation, but cytoskeletal organization is better preserved with mexiletine.

Effects of methylprednisolone and hyperbaric oxygen on oxidative status after experimental spinal cord injury: a comparative study in rats

The effects of hyperbaric oxygen (HBO) therapy or methylprednisolone on the oxidative status were evaluated in experimental spinal cord injury. Clip compression method was used to produce acute spinal cord injury rats. Hyperbaric oxygen was administered twice daily for a total of eight 90 min-sessions at 2.8 atmospheres. Methylprednisolone was first injected with a bolus of 30 mg/kg followed with an infusion rate of 5.4 mg/kg/h for 24 h. Five days after clip application animals were sacrificed and their traumatized spinal cord segment were excised. Tissue levels of thiobarbituric acid reactive substances (TBARS), superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) were evaluated to reflect oxidant/antioxidant status. Non-treated clip-operated animals reflected significantly higher SOD, GSH-Px and TBARS levels that were found to be significantly higher than the sham-operated. Methylprednisolone was not able to lower these levels. HBO administration diminished all measured parameters significantly; however, their levels appeared already to be high when compared with sham animals. According to these results obtained on the 5th day after induction, HBO, but not methylprednisolone, seems to procure prevention against oxidative spinal cord injury.

Plasma vitamin E and selenium levels in rats with head trauma

BACKGROUND

Free radicals play an important role in brain damage induced by a head trauma. In this study, we examined the prevention of brain damage that occurs after oxidative stress in rats that had undergone an experimental head trauma and the determination of plasma levels of vitamin E and selenium, which are recognized as antioxidant agents.

METHODS

In this study, adult male Sprague-Dawley rats were used. Rats were divided into 2 groups. In the first group (control group, n = 10), pretraumatic plasma selenium and vitamin E levels were investigated and rats were not traumatized. In the second group (trauma group, n = 10), posttraumatic plasma selenium and vitamin E levels were investigated at the 6th and 24th hours in traumatized rats.

RESULTS

In the control group, the plasma selenium level was 107 +/- 8.113 microg/L, whereas vitamin E level was 1.310 +/- 0.048 mg/dL. In the trauma group, the plasma selenium level was 79.93 +/- 3.130 microg/L at the 6th hour and 74.74 +/- 2.947 microg/L at the 24th hour, whereas the vitamin E level was 1.211 +/- 0.056 mg/dL at the 6th hour and 1.136 +/- 0.044 mg/dL at the 24th hour. Normal plasma selenium and vitamin E levels were significantly reduced in the early period after trauma.

CONCLUSION

Because of oxidative stress that occurs directly after a head trauma, vitamin E and selenium depletion occurs in the early period. This condition supports the idea that brain damage can be reduced if decreased antioxidants are replaced when a head trauma occurs. We believe that these findings will guide and assist in future studies to develop clinical management strategies to prevent brain damage induced by head trauma.

Role of oxidative stress in experimental sepsis and multisystem organ dysfunction

Massive increase in radical species can lead to oxidative stress, promoting cell injury and death. This review focuses on experimental evidence of oxidative stress in critical illnesses, sepsis and multisystem organ dysfunction. Oxidative stress could negatively affect organ injury and thus overall survival of experimental models. Based on this experimental evidence, we could improve the rationale of supplementation of antioxidants alone or in combination with standard therapies aimed to reduce oxidative stress as novel adjunct treatment in critical care.

Oxidative stress in head trauma in aging

Oxidative damage is proposed as a key mediator of exacerbated morphological responses and deficits in behavioral recovery in aged subjects with traumatic brain injury (TBI). In the present study, we show exacerbated loss of tissue in middle aged (12 months) and aged (22 months) Fisher-344 rats compared to young animals (3 months) subjected to moderate TBI. Analysis of 4-hydroxynonenal (4-HNE) and acrolein, neurotoxic by-products of lipid peroxidation, shows significant (P < 0.05) age-dependent increases in ipsilateral (IP) hippocampus 1 and 7 days post injury. In IP cortex, 4-HNE was significantly elevated 1 day post injury in all age groups, and both 4-HNE and acrolein were elevated in middle aged and aged animals 7 days post injury. Comparison of antioxidant enzyme activities shows significant (P < 0.05) age-dependent decreases of manganese superoxide dismutase in IP hippocampus and cortex 1 and 7 days post injury. Glutathione reductase activity also showed an age-dependent decrease. Overall, our data show increased levels of oxidative damage, diminished antioxidant capacities, and increased tissue loss in TBI in aging.

Traumatic injury to the immature brain: inflammation, oxidative injury, and iron-mediated damage as potential therapeutic targets

Traumatic brain injury (TBI) is the leading cause of morbidity and mortality among children and both clinical and experimental data reveal that the immature brain is unique in its response and vulnerability to TBI compared to the adult brain. Current therapies for pediatric TBI focus on physiologic derangements and are based primarily on adult data. However, it is now evident that secondary biochemical perturbations play an important role in the pathobiology of pediatric TBI and may provide specific therapeutic targets for the treatment of the head-injured child. In this review, we discuss three specific components of the secondary pathogenesis of pediatric TBI-- inflammation, oxidative injury, and iron-induced damage-- and potential therapeutic strategies associated with each. The inflammatory response in the immature brain is more robust than in the adult and characterized by greater disruption of the blood-brain barrier and elaboration of cytokines. The immature brain also has a muted response to oxidative stress compared to the adult due to inadequate expression of certain antioxidant molecules. In addition, the developing brain is less able to detoxify free iron after TBI-induced hemorrhage and cell death. These processes thus provide potential therapeutic targets that may be tailored to pediatric TBI, including anti-inflammatory agents such as minocycline, antioxidants such as glutathione peroxidase, and the iron chelator deferoxamine.

Therapeutic efficacy of intraventricular cyclosporine A and methylprednisolone on a global cerebral ischemia model in rats

OBJECTIVE

Cyclosporine A (CsA) with its immunosuppressive actions and methylprednisolone (MP) as a free radical scavenger were suggested together to alleviate neural tissue damage after an ischemic insult. The aim of this study was to investigate neuroprotective properties of CsA and MP in a global cerebral ischemia model.

METHODS

Twenty-eight male Sprague-Dawley rats were divided randomly into four separate groups: CsA, MP, sham and control. Global cerebral ischemia was performed with the four-vessel occlusion model. After 30 minutes of ischemia, reperfusion was started with concomitant intraventricular administration of saline, MP (20 mg/kg) and CsA (10 mg/kg) into the lateral ventricle. Lipid peroxidation levels were measured from all experimental groups. Rats subjected to global cerebral ischemia exhibited a significant increase in cerebral lipid peroxide levels 6 hours after the onset of reperfusion. Both CsA and MP treatment significantly attenuated the degree of lipid peroxidation in cerebral tissues (p<0.05). Histopathological examinations of the CA1 sector of the hippocampus verified the neuroprotective properties of MP and CsA.

CONCLUSIONS

The results suggested the neuroprotective properties of both agents, emphasizing more potent protection against ischemia by CsA. It was proposed that CsA could have exerted this effect with the blockage of mitochondrial permeability transition (MPT) pores, which are also critical if the necrotic and apoptotic cascades of the cell are considered. MP is judged to be neuroprotective, particularly in terms of its effects on lipid peroxidation. In conclusion, CsA and MP are ascertained to be neuroprotective agents as long as they cross the blood-brain barrier.

Administration of riboflavin improves behavioral outcome and reduces edema formation and glial fibrillary acidic protein expression after traumatic brain injury

Previous studies have shown that administration of riboflavin, vitamin B2, significantly reduced edema formation following experimental stroke. The present study evaluated the ability of B2 to improve behavioral function, reduce edema formation, and limit glial fibrillary acidic protein (GFAP) expression following frontal cortex contusion injury. Groups of rats were assigned to B2 (7.5 mg/kg) or saline (1.0 ml/kg) treatment conditions and received contusion injuries or sham procedures. Drug treatment was administered 15 min and 24 h following injury. Rats were examined on a variety of tests to measure sensorimotor performance (bilateral tactile removal test), and cognitive ability (acquisition of reference and working memory) in the Morris water maze. Administration of B2 following injury significantly reduced the behavioral impairments observed on the bilateral tactile removal test and improved the acquisition of both reference and working memory tests compared to saline-treated rats. The lesion analysis showed that B2 reduced the size of the lesion. Examination of GFAP expression around the lesion revealed that B2 significantly reduced the number of GFAP+ astrocytes. Edema formation following injury was also significantly reduced by B2 administration. These findings are the first to show that B2 administration significantly improved behavioral outcome and reduced lesion volume, edema formation, and the expression of GFAP following traumatic brain injury. These findings suggest that B2 may have therapeutic potential for the treatment of TBI.

Bromocriptine reduces lipid peroxidation and enhances spatial learning and hippocampal neuron survival in a rodent model of focal brain trauma

Oxidative stress is a significant contributor to the secondary sequelae of traumatic brain injury (TBI), and may mediate subsequent neurobehavioral deficits and histopathology. The present study examined the neuroprotective effects of bromocriptine (BRO), a dopamine D2 receptor agonist with significant antioxidant properties, on cognition, histopathology, and lipid peroxidation in a rodent model of focal brain trauma. BRO (5 mg/kg) or a comparable volume of vehicle (VEH) was administered intraperitoneally 15 min prior to cortical impact or sham injury. In experiment 1, spatial learning was assessed in an established water maze task on post-surgery days 14-18, followed by quantification of hippocampal cell survival and cortical lesion volume at 4 weeks. In experiment 2, rats were sacrificed 1 hr post-surgery, and malondialdehyde (MDA), the end product of lipid peroxidation, was measured in the frontal cortex, striatum, and substantia nigra using a thiobarbituric acid reactive substances assay. The TBI+BRO group was significantly more adept at locating a hidden platform in the water maze compared to the TBI+VEH group and also exhibited a greater percentage of surviving CA3 hippocampal neurons. TBI increased MDA in all examined regions of the VEH-treated, but not BRO-treated group versus SHAMs. MDA was significantly decreased in both the striatum (4.22 +/- 0.52 versus 5.60 +/- 0.44 nmol per mg/tissue +/- SEM) and substantia nigra (4.18 +/- 0.35 versus 7.76 +/- 2.05) of the TBI+BRO versus TBI+VEH groups, respectively, while only a trend toward decreased MDA was observed in the frontal cortex (5.44 +/- 0.44 versus 6.96 +/- 0.77). These findings suggest that TBI-induced oxidative stress is attenuated by acute BRO treatment, which may, in part, explain the benefit in cognitive and histological outcome.

Tocopherol (vitamin E) in Alzheimer's disease and other neurodegenerative disorders

In this article, we review the evidence that tocopherol (vitamin E) may have a role to play in the prevention and treatment of Alzheimer's disease and other neurological diseases. The theoretical rationale for the effectiveness of tocopherol as treatment and/or prevention of Alzheimer's disease is based on its antioxidant properties. Results from animal and in vitro studies provide evidence to support use of tocopherol for prevention and treatment of degenerative neurological diseases. Furthermore, several, but not all, epidemiological, cross-sectional, prospective studies indicate that tocopherol may have protective effects in Alzheimer's disease, although dietary and supplemental forms of the vitamin may differ in their efficacy. Mixed results have been obtained from clinical trials. Evidence of the use of tocopherol as a protective measure or as therapy in neurological diseases other than Alzheimer's disease is less compelling. To date, there are no clear-cut answers as to whether tocopherol is worth prescribing, but current clinical practice favours its use in the treatment of Alzheimer's disease.

Time Course Analysis of Hippocampal Nerve Growth Factor and Antioxidant Enzyme Activity following Lateral Controlled Cortical Impact Brain Injury in the Rat

Gradual secondary injury processes, including the release of toxic reactive oxygen species, are important components of the pathogenesis of traumatic brain injury (TBI). The extent of oxidative stress is determined in part by the effectiveness of the antioxidant response, involving the enzymes glutathione peroxidase (GPx), catalase (CAT), and superoxide dismutase (SOD). Since nerve growth factor (NGF) may be involved in the initiation of antioxidant activity, we employed a controlled cortical impact injury model in rats to produce secondary hippocampal damage and determined the subsequent time course of changes in NGF production and GPx, CAT, and SOD activity in this brain region. Hippocampal NGF production showed a rapid increase with a biphasic response after TBI. NGF protein was increased at 6 h, plateaued at 12 h, declined by 7 days, and exhibited a second rise at 14 days after injury. Similar to NGF, hippocampal GPx activity also showed a biphasic response, increasing by 12 h, declining at 24 h, and exhibiting a second peak at 7 days. In contrast, increased CAT activity occured steadily from 1 day through 7 days after injury. SOD activity was decreased at 6 h after injury, and continued to decline through 14 days. The initial rise in NGF preceded that of CAT, and coincided with an increase in GPX and a drop in SOD activity. These data demonstrate a complex temporal spectrum of antioxidant enzyme activation following secondary brain injury in the hippocampus, and suggest a selective regulatory role for NGF in this response.

Treatment with vitamin B3 improves functional recovery and reduces GFAP expression following traumatic brain injury in rats

Previous studies have shown that administration of vitamin B(3) (B(3)) in animal models of ischemia significantly reduced the size of infarction and improved functional recovery. The present study evaluated the effect of administration of B(3) on recovery of function following traumatic brain injury (TBI), incorporating the bilateral medial frontal cortex contusion injury model. Groups of rats were assigned to B(3) (500 mg/kg) or saline (1.0 ml/kg) treatment conditions and received contusion injuries or sham surgeries. Drug treatment was administered 15 min and 24 h following injury. Rats were examined on a variety of tests to measure sensorimotor performance (bilateral tactile adhesive removal), skilled forelimb use (staircase test), and cognitive ability (reference and working memory) in the Morris Water Maze. Administration of B(3) following injury significantly reduced the behavioral impairments observed on the bilateral tactile removal test, but not on skilled forelimb use. The acquisition of reference and working memory tests were also significantly improved compared to saline-treated rats. Examination of the brains revealed that administration of B(3) significantly reduced the size of the lesion compared to treatment with saline. In addition, examination of glial fibrillary acidic protein (GFAP) expression around the lesion revealed that B(3) significantly reduced the number of GFAP(+) astrocytes. These results indicate that B(3) administration significantly improved behavioral outcome following injury, reduced the size of the lesion, and reduced the expression of GFAP. The current findings suggest that B(3) may have therapeutic potential for the treatment of TBI.

Caffeine impairs short-term neurological outcome after concussive head injury in rats

OBJECTIVE

Adenosine is an endogenous neuroprotective agent that is released during ischemia, hypoxia, epilepsy, and ischemic brain injury. Caffeine is a receptor antagonist for adenosine that might interfere with the neuroprotective effect of adenosine in ischemic-hypoxic conditions. An investigation was undertaken to study the effect of caffeine on neurological function, edema formation, and blood-brain barrier permeability after experimental head injury in rats.

METHODS

Adult female Wistar rats classified into different groups received caffeine intraperitoneally at doses of 0, 50, 100, and 150 mg/kg body weight. Thirty minutes after the caffeine treatment, the animals were subjected to concussive head injury (CHI) administered by a controlled cortical impact device. Neurological severity score was recorded in each rat at 2 hours after CHI. Specific gravity, water content (as an indicator of edema), and blood-brain barrier impairment were analyzed in the cortical tissue surrounding the injury site. The levels of myeloperoxidase and malondialdehyde in the cortical region were measured as indicators of neutrophil infiltration and lipid peroxidation, respectively.

RESULTS

A significant increase in righting latency and neurological deficiency after CHI was observed in caffeine-treated rats as compared with untreated animals. Although no deaths occurred in the rats exposed to CHI after pretreatment with saline, pretreatment with caffeine caused significant mortality of animals after trauma in a dose-dependent manner. Caffeine also exacerbated neutrophil infiltration, edema, and disruption of blood-brain barrier in the traumatic cortex. Light microscopy of brain revealed more severe hemorrhage and neuronal degeneration in the injured hemisphere of caffeine-treated rats as compared with rats in the injury-alone group. A significant increase in malondialdehyde in the brain of injured rats treated with caffeine before CHI clearly indicated the role of oxidative stress.

CONCLUSION

Caffeine adversely affects outcome after CHI, possibly as a result of blockade of adenosine receptors. The findings also point toward the involvement of free radical-mediated neuronal damage in caffeine-induced exacerbation of neurotrauma.

Lipid peroxidation in cerebral tumors

BACKGROUND

Serum and tissue concentrations of tumor markers or some metabolites are considered to be helpful in diagnosis and follow-up of the central nervous system (CNS) disease. However, markers currently available are not sufficiently sensitive and specific to be used as actual diagnostic tools. Differentiation between the malignant and benign lesions of the CNS is very important, both for determining the optimum therapeutic approach and to predict morbidity and mortality of the disease. Accurate diagnosis of a malignant disease is mostly performed through a surgical resection and histopathologic evaluation. Free oxygen radicals (FOR) are thought to take part in oncogenesis and cellular differentiation. We explored whether FORs can be used as diagnostic tumor markers.

METHODS

We investigated the concentration of malondialdehyde (MDA) in the serum and tumor tissue of patients with glial tumor. We have studied 30 patients with malign glial tumor (grades III and IV astrocytoma), 30 patients with low grade glial tumor, 28 healthy individuals, and 10 patients with nontumorous lesions (lobectomy for epilepsy).

RESULTS

Patients with CNS tumors showed higher serum MDA concentration compared to control groups (epilepsy patients and healthy subjects). These patients had a higher tumor tissue MDA concentration compared to lobectomy tissue from epilepsy patients. Serum and tissue MDA concentrations were also higher in the malignant glial tumor group compared to the low grade glial tumor group.

CONCLUSIONS

Although not specific, tissue and serum concentrations of FORs can be used as a marker to detect the presence and grade of CNS tumors. Further studies are needed to determine the optimum cutoff value for use of serum and tissue MDA concentrations in brain tumors.

Oxidative damage after severe head injury and its relationship to neurological outcome

OBJECTIVE

We sought to establish the time course of reactive oxygen species after severe head injuries in humans and to investigate their relationship with clinical outcomes.

METHODS

Both the markers of oxidative damage-malonylaldehyde (MDA) and the enzymatic and nonenzymatic antioxidant defenses (i.e., superoxide dismutase [SOD] and vitamin E [VE], respectively)-were studied. To assess the time course of MDA, SOD, and VE, jugular bulb (JB) and peripheral venous blood samples were obtained from 30 patients within 8 hours of severe head trauma onset (T(0)) and 6 (T(1)), 12 (T(2)), 24 (T(3)), and 48 hours (T(4)) after trauma onset. Patients were divided into good and poor outcome groups according to their 6-month neurological outcome as determined on the basis of their Glasgow Outcome Scale scores and biochemical profiles.

RESULTS

In JB samples, MDA levels increased significantly at T(1), T(2), T(3), and T(4) as compared with T(0); SOD activity increased significantly at T(2) and T(3) as compared with T(0); and VE levels decreased significantly at T(1), T(2), and T(3) as compared with T(0). The same variables did not change significantly over time in peripheral venous blood samples. Moreover, the MDA levels and SOD activity detected in JB samples were significantly higher in the poor outcome group at T(1) and T(2). No significant difference in VE levels was observed between the two outcome groups.

CONCLUSION

Reactive oxygen species-mediated oxidative damage can play an important role in determining the prognosis of severe brain injury in humans.