Selective COX-2 Inhibitors as Neuroprotective Agents in Traumatic Brain Injury

Traumatic brain injury (TBI) is a significant contributor to mortality and morbidity in people, both young and old. There are currently no approved therapeutic interventions for TBI. Following TBI, cyclooxygenase (COX) enzymes generate prostaglandins and reactive oxygen species that perpetuate inflammation, with COX-1 and COX-2 isoforms providing differing responses. Selective COX-2 inhibitors have shown potential as neuroprotective agents. Results from animal models of TBI suggest potential treatment through the alleviation of secondary injury mechanisms involving neuroinflammation and neuronal cell death. Additionally, early clinical trials have shown that the use of celecoxib improves patient mortality and outcomes. This review aims to summarize the therapeutic effects of COX-2 inhibitors observed in TBI animal models, highlighting pertinent studies elucidating molecular pathways and expounding upon their mechanistic actions. We then investigated the current state of evidence for the utilization of COX-2 inhibitors for TBI patients.

Early Celecoxib use in Patients with Traumatic Brain Injury

BACKGROUND

Traumatic brain injury (TBI) can cause rapid brain inflammation. There is debate over the safety and efficacy of anti-inflammatory agents in its treatment. With a particular focus on cyclooxygenase 2 (COX2) selective inhibition, we sought to determine the impact of celecoxib versus no celecoxib treatment on outcomes in patients with TBI and compare these with outcomes associated with nonselective COX inhibition (ibuprofen) and corticosteroid (dexamethasone) treatment.

METHODS

This retrospective cohort study used TriNetX, a large publicly available global health research network, to gather clinical data extracted from the electronic medical records. Using International Classification of Diseases, Tenth Revision and pharmacy codes, we identified patients with TBI who were and were not treated with celecoxib, ibuprofen, and dexamethasone. Analysis was performed on propensity-matched and unmatched cohorts, which were matched on demographics, comorbidities, and neurological injuries. Our primary end point was 1-year survival. Secondary end points were ventilator and tracheostomy dependence, gastrostomy tube placement, seizures, and craniotomy.

RESULTS

After propensity score matching, a total of 1443 patients were identified in both the celecoxib and no celecoxib cohorts. Ninety-two (6.4%) patients in the celecoxib cohort died within 1 year following TBI versus 145 (10.0%) in the no celecoxib cohort (odds ratio 0.61; 95% confidence interval 0.46-0.80; p = 0.0003). The 1-year survival rate was 96.1% in the celecoxib cohort versus 93.1% in the no celecoxib cohort (p < 0.0001). At the end of the 1-year period, celecoxib was associated with significantly lower gastrostomy tube dependence (p = 0.017), seizure activity (p = 0.027), and myocardial infarction (p = 0.021) compared with the control cohort. Ibuprofen was also associated with higher 1-year survival probability and lower rates of post-TBI complications. Dexamethasone was broadly associated with higher morbidity but was associated with higher 1-year survival probability compared with the no dexamethasone cohort.

CONCLUSIONS

Early celecoxib and ibuprofen use within 5 days post TBI was associated with higher 1-year survival probabilities and fewer complications. With emerging yet controversial preclinical evidence to suggest that COX inhibition improves TBI outcomes, this population-level study offers suggestive support for these drugs' clinical benefit, which should be pursued in prospective clinical studies.

The Interplay between Ferroptosis and Neuroinflammation in Central Neurological Disorders

Central neurological disorders are significant contributors to morbidity, mortality, and long-term disability globally in modern society. These encompass neurodegenerative diseases, ischemic brain diseases, traumatic brain injury, epilepsy, depression, and more. The involved pathogenesis is notably intricate and diverse. Ferroptosis and neuroinflammation play pivotal roles in elucidating the causes of cognitive impairment stemming from these diseases. Given the concurrent occurrence of ferroptosis and neuroinflammation due to metabolic shifts such as iron and ROS, as well as their critical roles in central nervous disorders, the investigation into the co-regulatory mechanism of ferroptosis and neuroinflammation has emerged as a prominent area of research. This paper delves into the mechanisms of ferroptosis and neuroinflammation in central nervous disorders, along with their interrelationship. It specifically emphasizes the core molecules within the shared pathways governing ferroptosis and neuroinflammation, including SIRT1, Nrf2, NF-κB, Cox-2, iNOS/NO·, and how different immune cells and structures contribute to cognitive dysfunction through these mechanisms. Researchers' findings suggest that ferroptosis and neuroinflammation mutually promote each other and may represent key factors in the progression of central neurological disorders. A deeper comprehension of the common pathway between cellular ferroptosis and neuroinflammation holds promise for improving symptoms and prognosis related to central neurological disorders.

Cyclic Hexapeptide from Bouvardia ternifolia (Cav.) Schltdl. and Neuroprotective Effects of Root Extracts

Bouvardia ternifolia (Cav.) Schltdl. is a shrub that belongs to the Rubiaceae family and is distributed throughout México; it has been used for its antioxidant, neuroprotective, and anti-inflammatory properties. This work aimed to evaluate the protective effects of B. ternifolia root extracts on the blood-brain barrier and the positive regulation of cytokines IL-1β, IL-6, and TNF-α, and the characterization of compounds present in the dichloromethane (BtD) and hexane (BtH) extracts. Male ICR mice were orally administered with B. ternifolia extracts for 5 days before a single injection of LPS. Administration of BtH and BtD significantly decreased Evans blue leakage into brain tissue by 70% and 68%, respectively. Meloxicam (MX) decreased the concentration of IL-1β by 39.6%; BtM by 53.9%; BtAq by 48.4%; BtD by 31.9%, and BtH by 37.7%. BtH was the only treatment that significantly decreased the concentration of IL-6 by 32.2%. The concentration of TNF-α declined with each of the treatments. The chemical composition of BtD and BtH was characterized by GC-MS, and the cyclic hexapeptide was identified by 13C, 1H NMR, and two-dimension techniques. In the BtD extract, seven compounds were found and in BtH 13 compounds were found. The methanolic (BtM) and aqueous (BtAq) extracts were not subjected to chemical analysis, because they did not show a significant difference in the BBB protection activity. Therefore, the results suggested that the extracts BtD and BtH protect the blood-brain barrier, maintaining stable its selective permeability, thereby preventing LPS from entering the brain tissue. Simultaneously, they modulate the production of IL-1β, IL-6, and TNF-α. It is important to note that this research only evaluated the complete extracts.

Relationships of pain-causing substances with dry skin and effects of zaltoprofen on alleviation of symptoms in arthritis model mice

Skin dryness is a symptom of rheumatoid arthritis (RA). However, the mechanisms through which dry skin is induced in RA are unclear. Accordingly, in this study, we characterized substances related to pruritus and pain and then evaluated whether oral administration of zaltoprofen (ZLT) alleviated the symptom of dry skin induced by RA in model mice. DBA/1JJmsSlc collagen-induced arthritis model mice were treated with ZLT, and transepidermal water loss (TEWL), capacitance, and inflammation-, pruritus-, and pain-related markers were assessed. Our findings demonstrated that arthritis model mice treated with ZLT exhibited suppression of increases in TEWL and decreases in capacitance. Furthermore, ZLT also blocked the increase in mast cell numbers, substance P expression, and cyclo-oxygenase-2 expression in the skin and prevented enhancement of plasma levels of thymic stromal lymphopoietin, tumor necrosis factor-α, interleukin-6, histamine, and bradykinin. No changes in plasma levels of corticosterone or reactive oxygen species or skin levels of glucocorticoid receptor were observed in ZLT-treated arthritis model mice. Overall, these findings suggested that patients with RA may benefit from biopharmacy to alleviate joint symptoms and nonsteroidal anti-inflammatory drugs for pain relief and alleviation of skin symptoms.

Pathogenesis and management of traumatic brain injury (TBI): role of neuroinflammation and anti-inflammatory drugs

Traumatic brain injury (TBI) is an important global health concern that represents a leading cause of death and disability. It occurs due to direct impact or hit on the head caused by factors such as motor vehicles, crushes, and assaults. During the past decade, an abundance of new evidence highlighted the importance of inflammation in the secondary damage response that contributes to neurodegenerative and neurological deficits after TBI. It results in disruption of the blood-brain barrier (BBB) and initiates the release of macrophages, neutrophils, and lymphocytes at the injury site. A growing number of researchers have discovered various signalling pathways associated with the initiation and progression of inflammation. Targeting different signalling pathways (NF-κB, JAK/STAT, MAPKs, PI3K/Akt/mTOR, GSK-3, Nrf2, RhoGTPase, TGF-β1, and NLRP3) helps in the development of novel anti-inflammatory drugs in the management of TBI. Several synthetic and herbal drugs with both anti-inflammatory and neuroprotective potential showed effective results. This review summarizes different signalling pathways, associated pathologies, inflammatory mediators, pharmacological potential, current status, and challenges with anti-inflammatory drugs.

Maternal Prenatal Inflammation Increases Brain Damage Susceptibility of Lipopolysaccharide in Adult Rat Offspring via COX-2/PGD-2/DPs Pathway Activation

A growing body of research suggests that inflammatory insult contributes to the etiology of central nervous system diseases, such as depression, Alzheimer’s disease, and so forth. However, the effect of prenatal systemic inflammation exposure on offspring brain development and cerebral susceptibility to inflammatory insult remains unknown. In this study, we utilized the prenatal inflammatory insult model in vivo and the neuronal damage model in vitro. The results obtained show that prenatal maternal inflammation exacerbates LPS-induced memory impairment, neuronal necrosis, brain inflammatory response, and significantly increases protein expressions of COX-2, DP2, APP, and Aβ, while obviously decreasing that of DP1 and the exploratory behaviors of offspring rats. Meloxicam significantly inhibited memory impairment, neuronal necrosis, oxidative stress, and inflammatory response, and down-regulated the expressions of APP, Aβ, COX-2, and DP2, whereas significantly increased exploring behaviors and the expression of DP1 in vivo. Collectively, these findings suggested that maternal inflammation could cause offspring suffering from inflammatory and behavioral disorders and increase the susceptibility of offspring to cerebral pathological factors, accompanied by COX-2/PGD-2/DPs pathway activation, which could be ameliorated significantly by COX-2 inhibitor meloxicam treatment.

The Neurobehavioral Effects of Buprenorphine and Meloxicam on a Blast-Induced Traumatic Brain Injury Model in the Rat

Previous findings have indicated that pain relieving medications such as opioids and non-steroidal anti-inflammatory drugs (NSAIDs) may be neuroprotective after traumatic brain injury in rodents, but only limited studies have been performed in a blast-induced traumatic brain injury (bTBI) model. In addition, many pre-clinical TBI studies performed in rodents did not use analgesics due to the possibility of neuroprotection or other changes in cognitive, behavioral, and pathology outcomes. To examine this in a pre-clinical setting, we examined the neurobehavioral changes in rats given a single pre-blast dose of meloxicam, buprenorphine, or no pain relieving medication and exposed to tightly-coupled repeated blasts in an advanced blast simulator and evaluated neurobehavioral functions up to 28 days post-blast. A 16.7% mortality rate was recorded in the rats treated with buprenorphine, which might be attributed to the physiologically depressive side effects of buprenorphine in combination with isoflurane anesthesia and acute brain injury. Rats given buprenorphine, but not meloxicam, took more time to recover from the isoflurane anesthesia given just before blast. We found that treatment with meloxicam protected repeated blast-exposed rats from vestibulomotor dysfunctions up to day 14, but by day 28 the protective effects had receded. Both pain relieving medications seemed to promote short-term memory deficits in blast-exposed animals, whereas vehicle-treated blast-exposed animals showed only a non-significant trend toward worsening short-term memory by day 27. Open field exploratory behavior results showed that blast exposed rats treated with meloxicam engaged in significantly more locomotor activities and possibly a lesser degree of responses thought to reflect anxiety and depressive-like behaviors than any of the other groups. Rats treated with analgesics to alleviate possible pain from the blast ate more than their counterparts that were not treated with analgesics, which supports that both analgesics were effective in alleviating some of the discomfort that these rats potentially experienced post-blast injury. These results suggest that meloxicam and, to a lesser extent buprenorphine alter a variety of neurobehavioral functions in a rat bTBI model and, because of their impact on these neurobehavioral changes, may be less than ideal analgesic agents for pre-clinical studies evaluating these neurobehavioral responses after TBI.

Mollusc-Derived Brominated Indoles for the Selective Inhibition of Cyclooxygenase: A Computational Expedition

Inflammation plays an important role in different chronic diseases. Brominated indoles derived from the Australian marine mollusk Dicathais orbita (D. orbita) are of interest for their anti-inflammatory properties. This study evaluates the binding mechanism and potentiality of several brominated indoles (tyrindoxyl sulfate, tyrindoleninone, 6-bromoisatin, and 6,6′-dibromoindirubin) against inflammatory mediators cyclooxygenases-1/2 (COX-1/2) using molecular docking, followed by molecular dynamics simulation, along with physicochemical, drug-likeness, pharmacokinetic (pk), and toxicokinetic (tk) properties. Molecular docking identified that these indole compounds are anchored, with the main amino acid residues, positioned in the binding pocket of the COX-1/2, required for selective inhibition. Moreover, the molecular dynamics simulation based on root mean square deviation (RMSD), radius of gyration (Rg), solvent accessible surface area (SASA), and root mean square fluctuation (RMSF) analyses showed that these natural brominated molecules transit rapidly to a progressive constant configuration during binding with COX-1/2 and seem to accomplish a consistent dynamic behavior by maintaining conformational stability and compactness. The results were comparable to the Food and Drug Administration (FDA)-approved selective COX inhibitor, aspirin. Furthermore, the free energy of binding for the compounds assessed by molecular mechanics–Poisson–Boltzmann surface area (MM–PBSA) confirmed the binding capacity of indoles towards COX-1/2, with suitable binding energy values except for the polar precursor tyrindoxyl sulfate (with COX-1). The physicochemical and drug-likeness analysis showed zero violations of Lipinski’s rule, and the compounds are predicted to have excellent pharmacokinetic profiles. These indoles are projected to be non-mutagenic and free from hepatotoxicity, with no inhibition of human ether-a-go–go gene (hERG) I inhibitors, and the oral acute toxicity LD₅₀ in rats is predicted to be similar or lower than aspirin. Overall, this work has identified a plausible mechanism for selective COX inhibition by natural marine indoles as potential therapeutic candidates for the mitigation of inflammation.

Genetic Modulators of Traumatic Brain Injury in Animal Models and the Impact of Sex-Dependent Effects

Traumatic brain injury (TBI) is a major health problem causing disability and death worldwide. There is no effective treatment, due in part to the complexity of the injury pathology and factors affecting its outcome. The extent of brain injury depends on the type of insult, age, sex, lifestyle, genetic risk factors, socioeconomic status, other co-injuries, and underlying health problems. This review discusses the genes that have been directly tested in TBI models, and whether their effects are known to be sex-dependent. Sex differences can affect the incidence, symptom onset, pathology, and clinical outcomes following injury. Adult males are more susceptible at the acute phase and females show greater injury in the chronic phase. TBI is not restricted to a single sex; despite variations in the degree of symptom onset and severity, it is important to consider both female and male animals in TBI pre-clinical research studies.

Challenges of Delirium Management in Patients with Traumatic Brain Injury: From Pathophysiology to Clinical Practice

Traumatic brain injury (TBI) can initiate a very complex disease of the central nervous system (CNS), starting with the primary pathology of the inciting trauma and subsequent inflammatory and CNS tissue response. Delirium has long been regarded as an almost inevitable consequence of moderate to severe TBI, but more recently has been recognized as an organ dysfunction syndrome with potentially mitigating interventions. The diagnosis of delirium is independently associated with prolonged hospitalization, increased mortality and worse cognitive outcome across critically ill populations. Investigation of the unique problems and management challenges of TBI patients is needed to reduce the burden of delirium in this population. In this narrative review, possible etiologic mechanisms behind post-traumatic delirium are discussed, including primary injury to structures mediating arousal and attention and secondary injury due to progressive inflammatory destruction of the brain parenchyma. Other potential etiologic contributors include dysregulation of neurotransmission due to intravenous sedatives, seizures, organ failure, sleep cycle disruption or other delirium risk factors. Delirium screening can be accomplished in TBI patients and the presence of delirium portends worse outcomes. There is evidence that multi-component care bundles including an analgesia-prioritized sedation algorithm, regular spontaneous awakening and breathing trials, protocolized delirium assessment, early mobility and family engagement can reduce the burden of ICU delirium. The aim of this review is to summarize the approach to delirium in TBI patients with an emphasis on pathogenesis and management. Emerging CNS-active drug therapies that show promise in preclinical studies are highlighted.

The effect of rosmarinic acid on deformities occurring in brain tissue by craniectomy method. Histopathological evaluation of IBA-1 and GFAP expressions

PURPOSE

To investigate the role of Rosmarinic acid (RA) in the prevention of traumatic brain injury and the immunohistochemical analysis of IBA-1 and GFAP expressions.

METHODS

Healthy male rats were randomly divided into 3 groups consisting of 10 rats. Groups were as follows; control group, traumatic brain injury (TBI) group, and TBI+RA group. After traumatic brain injury, blood samples were taken from the animals and analyzed with various biochemical markers. And then IBA-1 and GFAP expressions were evaluated immunohistochemically.

RESULTS

Significant results were obtained in all biochemical parameters between groups. Immunohistochemical sections showed IBA-1 not only in microglia and macrophage activity but also in degenerative neurons in blood vessel endothelial cells. However, GFAP reaction and post-traumatic rosmarinic acid administration showed positive expression in astrocytes with regular structure around the blood vessel.

CONCLUSION

Rosmarinic acid in blood vessel endothelial cells showed that preserving the integrity of astrocytic structure in the blood brain barrier may be an important antioxidant.

Effects of Diclofenac Versus Meloxicam in Pentylenetetrazol-Kindled Mice

Epilepsy comes after stroke as the most common chronic neurological disorder worldwide. Inflammation enhances neuronal hyperexcitability that could provide a background setting for the development of epilepsy. The aim of this study was to assess the effect of valproate (VAL), diclofenac (DIC), meloxicam (MEL), VAL + MEL and VAL + DIC in pentylenetetrazol (PTZ) kindled mice. Seventy mice were randomly allocated into 7 equal groups; Control, PTZ, VAL, DIC, MEL, VAL + MEL and VAL + DIC groups. Kindling was induced by PTZ (40 mg/kg, i.p.) injection every other day for 17 days. The drugs were administered, 30 min before each PTZ injection till the end of the schedule. Seizure score, latency, duration and mortality rate were recorded in all groups. Tumor necrosis factor- α (TNF-α), interleukin-1β (IL-1β), malondialdehyde (MDA) and prostaglandin E2 (PGE2) levels as well as reduced glutathione (GSH) content were assessed in brain homogenate at the end of the schedule. VAL, DIC, MEL, VAL + MEL and VAL + DIC decreased seizure score and duration. Meanwhile, they increased the latency period. PTZ increased TNF-α, IL-1β, MDA, and PGE2 levels meanwhile, it decreased GSH content. Administration of VAL, DIC, MEL, VAL + MEL and VAL + DIC decreased TNF-α, IL-1β, MDA, and PGE2 levels meanwhile, they increased GSH content in the brain homogenates. Effects of VAL + DIC combination on the studied parameters were significant in relation to VAL. VAL, DIC, MEL, VAL + MEL and VAL + DIC produced anticonvulsant effect and mitigated inflammation and oxidative stress in PTZ-kindled mice. Interestingly, DIC rather than MEL enhanced the anticonvulsant effect VAL.

Management of Traumatic Brain Injury: From Present to Future

TBI (traumatic brain injury) is a major cause of death among youth in industrialized societies. Brain damage following traumatic injury is a result of direct and indirect mechanisms; indirect or secondary injury involves the initiation of an acute inflammatory response, including the breakdown of the blood–brain barrier (BBB), brain edema, infiltration of peripheral blood cells, and activation of resident immunocompetent cells, as well as the release of numerous immune mediators such as interleukins and chemotactic factors. TBI can cause changes in molecular signaling and cellular functions and structures, in addition to tissue damage, such as hemorrhage, diffuse axonal damages, and contusions. TBI typically disturbs brain functions such as executive actions, cognitive grade, attention, memory data processing, and language abilities. Animal models have been developed to reproduce the different features of human TBI, better understand its pathophysiology, and discover potential new treatments. For many years, the first approach to manage TBI has been treatment of the injured tissue with interventions designed to reduce the complex secondary-injury cascade. Several studies in the literature have stressed the importance of more closely examining injuries, including endothelial, microglia, astroglia, oligodendroglia, and precursor cells. Significant effort has been invested in developing neuroprotective agents. The aim of this work is to review TBI pathophysiology and existing and potential new therapeutic strategies in the management of inflammatory events and behavioral deficits associated with TBI.

Poldip2 mediates blood-brain barrier disruption in a model of sepsis-associated encephalopathy

Background

Sepsis-associated encephalopathy (SAE), a diffuse cerebral dysfunction in the absence of direct CNS infection, is associated with increased rates of mortality and morbidity in patients with sepsis. Increased cytokine production and disruption of the blood-brain barrier (BBB) are implicated in the pathogenesis of SAE. The induction of pro-inflammatory mediators is driven, in part, by activation of NF-κΒ. Lipopolysaccharide (LPS), an endotoxin produced by gram-negative bacteria, potently activates NF-κΒ and its downstream targets, including cyclooxygenase-2 (Cox-2). Cox-2 catalyzes prostaglandin synthesis and in the brain prostaglandin, E2 is capable of inducing endothelial permeability. Depletion of polymerase δ-interacting protein 2 (Poldip2) has previously been reported to attenuate BBB disruption, possibly via regulation of NF-κΒ, in response to ischemic stroke. Here we investigated Poldip2 as a novel regulator of NF-κΒ/cyclooxygenase-2 signaling in an LPS model of SAE.

Methods

Intraperitoneal injections of LPS (18 mg/kg) were used to induce BBB disruption in Poldip2^+/+ and Poldip2^+/− mice. Changes in cerebral vascular permeability and the effect of meloxicam, a selective Cox-2 inhibitor, were assessed by Evans blue dye extravasation. Cerebral cortices of Poldip2^+/+ and Poldip2^+/− mice were further evaluated by immunoblotting and ELISA. To investigate the role of endothelial Poldip2, immunofluorescence microscopy and immunoblotting were performed to study the effect of siPoldip2 on LPS-mediated NF-κΒ subunit p65 translocation and Cox-2 induction in rat brain microvascular endothelial cells. Finally, FITC-dextran transwell assay was used to assess the effect of siPoldip2 on LPS-induced endothelial permeability.

Results

Heterozygous deletion of Poldip2 conferred protection against LPS-induced BBB permeability. Alterations in Poldip2^+/+ BBB integrity were preceded by induction of Poldip2, p65, and Cox-2, which was not observed in Poldip2^+/− mice. Consistent with these findings, prostaglandin E2 levels were significantly elevated in Poldip2^+/+ cerebral cortices compared to Poldip2^+/− cortices. Treatment with meloxicam attenuated LPS-induced BBB permeability in Poldip2^+/+ mice, while having no significant effect in Poldip2^+/− mice. Moreover, silencing of Poldip2 in vitro blocked LPS-induced p65 nuclear translocation, Cox-2 expression, and endothelial permeability.

Conclusions

These data suggest Poldip2 mediates LPS-induced BBB disruption by regulating NF-κΒ subunit p65 activation and Cox-2 and prostaglandin E2 induction. Consequently, targeted inhibition of Poldip2 may provide clinical benefit in the prevention of sepsis-induced BBB disruption.

Electronic supplementary material

The online version of this article (10.1186/s12974-019-1575-4) contains supplementary material, which is available to authorized users.

A Systematic Review of Closed Head Injury Models of Mild Traumatic Brain Injury in Mice and Rats

Mild TBI (mTBI) is a significant health concern. Animal models of mTBI are essential for understanding mechanisms, and pathological outcomes, as well as to test therapeutic interventions. A variety of closed head models of mTBI that incorporate different aspects (i.e., biomechanics) of the mTBI have been reported. The aim of the current review was to compile a comprehensive list of the closed head mTBI rodent models, along with the common data elements, and outcomes, with the goal to summarize the current state of the field. Publications were identified from a search of PubMed and Web of Science and screened for eligibility following PRISMA guidelines. Articles were included that were closed head injuries in which the authors classified the injury as mild in rats or mice. Injury model and animal-specific common data elements, as well as behavioral and histological outcomes, were collected and compiled from a total of 402 articles. Our results outline the wide variety of methods used to model mTBI. We also discovered that female rodents and both young and aged animals are under-represented in experimental mTBI studies. Our findings will aid in providing context comparing the injury models and provide a starting point for the selection of the most appropriate model of mTBI to address a specific hypothesis. We believe this review will be a useful starting place for determining what has been done and what knowledge is missing in the field to reduce the burden of mTBI.

In search of antiepileptogenic treatments for post-traumatic epilepsy

Post-traumatic epilepsy (PTE) is diagnosed in 20% of individuals with acquired epilepsy, and can impact significantly the quality of life due to the seizures and other functional or cognitive and behavioral outcomes of the traumatic brain injury (TBI) and PTE. There is no available antiepileptogenic or disease modifying treatment for PTE. Animal models of TBI and PTE have been developed, offering useful insights on the value of inflammatory, neurodegenerative pathways, hemorrhages and iron accumulation, calcium channels and other target pathways that could be used for treatment development. Most of the existing preclinical studies test efficacy towards pathologies of functional recovery after TBI, while a few studies are emerging testing the effects towards induced or spontaneous seizures. Here we review the existing preclinical trials testing new candidate treatments for TBI sequelae and PTE, and discuss future directions for efforts aiming at developing antiepileptogenic and disease-modifying treatments.

Meloxicam Improves Cognitive Impairment of Diabetic Rats through COX2-PGE2-EPs-cAMP/pPKA Pathway

Diabetics often face greater risk of cognitive impairment than nondiabetics. However, how to prevent this disease is still unconfirmed. In this study, we investigated the potential protection and mechanism of meloxicam on cognitive impairment in diabetic rats. The diabetic rat model was established with a high-fat diet and a small dose of streptozotocin (40 mg/kg). The changes of spatial learning and memory, histopathology, and the protein expressions of amyloid protein precursor (APP) and β-amyloid (Aβ) indicated that diabetic rats had neuronal injury and cognitive impairment. Tumor necrosis factor α (TNFα), interleukin 6 (IL-6), C reactive protein (CRP) and prostaglandin E2 (PGE2) levels, and microglial cell number were significantly increased in the diabetic rat brain. Meanwhile, the protein expressions of APP, Aβ, cyclooxygenases2 (COX2), E-type prostanoid recptors 1 (EP1) and EP2, and the level of cyclic adenosine monophosphate (cAMP) were significantly increased, while the protein expressions of EP3 and phosphorylated protein kinase A (pPKA) were significantly decreased in the diabetic rat hippocampus and cortex. However, the EP4 protein expression had no significant changes. Meloxicam significantly improved neuronal injury and cognitive impairment, and significantly decreased inflammatory cytokines levels. Meloxicam also significantly decreased the protein expressions of APP, Aβ, COX2, EP1 and EP2, and the level of cAMP and significantly increased the EP3 and pPKA protein expressions in rat hippocampus and cortex. However, meloxicam did not significantly influence the levels of blood glucose, lipids, and insulin of rats. Our results suggest that meloxicam could significantly protect diabetic rats from cognitive impairment via a mechanism that may be associated with rebalancing the COX2-PGE2-EPs-cAMP/PKA pathway.

Ganoderma Lucidum Protects Rat Brain Tissue Against Trauma-Induced Oxidative Stress

Objective

Traumatic brain injury causes tissue damage, breakdown of cerebral blood flow and metabolic regulation. This study aims to investigate the protective influence of antioxidant Ganoderma lucidum (G. lucidum) polysaccharides (GLPs) on brain injury in brain-traumatized rats.

Methods

Sprague-Dawley conducted a head-traumatized method on rats by dropping off 300 g weight from 1 m height. Groups were categorized as control, G. lucidum, trauma, trauma+ G. lucidum (20 mL/kg per day via gastric gavage). Brain tissues were dissected from anesthetized rats 7 days after injury. For biochemical analysis, malondialdehyde, glutathione and myeloperoxidase values were measured.

Results

In histopathological examination, neuronal damage in brain cortex and changes in blood brain barrier were observed. In the analysis of immunohistochemical and western blot, p38 mitogen-activated protein kinase, vascular endothelial growth factor and cluster of differentiation 68 expression levels were shown. These analyzes demonstrated the beneficial effects of GLPs on brain injury.

Conclusion

We propose that GLPs treatment after brain injury could be an alternative treatment to decraseing inflammation and edema, preventing neuronal and glial cells degeneration if given in appropriate dosage and in particular time intervals.

Therapies targeting lipid peroxidation in traumatic brain injury

Lipid peroxidation can be broadly defined as the process of inserting a hydroperoxy group into a lipid. Polyunsaturated fatty acids present in the phospholipids are often the targets for peroxidation. Phospholipids are indispensable for normal structure of membranes. The other important function of phospholipids stems from their role as a source of lipid mediators - oxygenated free fatty acids that are derived from lipid peroxidation. In the CNS, excessive accumulation of either oxidized phospholipids or oxygenated free fatty acids may be associated with damage occurring during acute brain injury and subsequent inflammatory responses. There is a growing body of evidence that lipid peroxidation occurs after severe traumatic brain injury in humans and correlates with the injury severity and mortality. Identification of the products and sources of lipid peroxidation and its enzymatic or non-enzymatic nature is essential for the design of mechanism-based therapies. Recent progress in mass spectrometry-based lipidomics/oxidative lipidomics offers remarkable opportunities for quantitative characterization of lipid peroxidation products, providing guidance for targeted development of specific therapeutic modalities. In this review, we critically evaluate previous attempts to use non-specific antioxidants as neuroprotectors and emphasize new approaches based on recent breakthroughs in understanding of enzymatic mechanisms of lipid peroxidation associated with specific death pathways, particularly apoptosis. We also emphasize the role of different phospholipases (calcium-dependent and -independent) in hydrolysis of peroxidized phospholipids and generation of pro- and anti-inflammatory lipid mediators. This article is part of a Special Issue entitled SI:Brain injury and recovery.

Meloxicam prevents COX-2-mediated post-surgical inflammation but not pain following laparotomy in mice

BACKGROUND

Inflammation is thought to be a major contributor to post-surgical pain, so non-steroidal anti-inflammatory drugs (NSAIDs) are commonly used analgesics. However, compared to rats, considerably less is known as to how successfully these prevent pain in mice.

METHODS

A fluorescent COX-2 selective probe was used for the first time to evaluate the post-surgical anti-inflammatory effects of meloxicam, and automated behaviour analyses (HomeCageScan; HCS), the Mouse Grimace Scale (MGS) and body weight changes to assess its pain-preventative properties. Groups of 8-9 BALB/c mice were subcutaneously injected with saline (0.3 mL) or meloxicam at (1, 5 or 20 mg/kg) 1 h before a 1.5-cm midline laparotomy. The probe or a control dye (2 mg/kg) was injected intravenously 3 h later. Imaging was used to quantify inflammation at 7, 24 and 48 h following surgery. HCS data and MGS scores were respectively obtained from video recordings and photographs before surgery and 24 h later.

RESULTS

Post-surgical inflammation was dose dependently reduced by meloxicam; with 5 or 20 mg/kg being most effective compared to saline. However, all mice lost weight, MGS scores increased and behavioural activity was reduced by surgery for at least 24 h with no perceivable beneficial effect of meloxicam on any of these potentially pain-associated changes.

CONCLUSIONS

Although meloxicam prevented inflammation, even large doses did not prevent post-laparotomy pain possibly arising due to a range of factors, including, but not limited to inflammation. MGS scoring can be applied by very naïve assessors and so should be effective for cage-side use.

The functional and structural changes in the basilar artery due to overpressure blast injury

Overpressure blast-wave induced brain injury (OBI) leads to progressive pathophysiologic changes resulting in a reduction in brain blood flow, blood brain barrier breakdown, edema, and cerebral ischemia. The aim of this study was to evaluate cerebral vascular function after single and repeated OBI. Male Sprague-Dawley rats were divided into three groups: Control (Naive), single OBI (30 psi peak pressure, 1 to 2 msec duration), and repeated (days 1, 4, and 7) OBI (r-OBI). Rats were killed 24 hours after injury and the basilar artery was isolated, cannulated, and pressurized (90 cm H2O). Vascular responses to potassium chloride (KCl) (30 to 100 mmol/L), endothelin-1 (10(-12) to 10(-7) mol/L), acetylcholine (ACh) (10(-10) to 10(-4) mol/L) and diethylamine-NONO-ate (DEA-NONO-ate) (10(-10) to 10(-4) mol/L) were evaluated. The OBI resulted in an increase in the contractile responses to endothelin and a decrease in the relaxant responses to ACh in both single and r-OBI groups. However, impaired DEA-NONO-ate-induced vasodilation and increased wall thickness to lumen ratio were observed only in the r-OBI group. The endothelin-1 type A (ET(A)) receptor and endothelial nitric oxide synthase (eNOS) immunoreactivity were significantly enhanced by OBI. These findings indicate that both single and r-OBI impairs cerebral vascular endothelium-dependent dilation, potentially a consequence of endothelial dysfunction and/or vascular remodelling in basilar arteries after OBI.

Blood-brain barrier dysfunction following traumatic brain injury

Traumatic brain injury is a serious cause of morbidity and mortality worldwide. After traumatic brain injury, the blood-brain barrier, the protective barrier between the brain and the intravascular compartment, becomes dysfunctional, leading to leakage of proteins, fluid, and transmigration of immune cells. As this leakage has profound clinical implications, including edema formation, elevated intracranial pressure and decreased perfusion pressure, much interest has been paid to better understanding the mechanisms responsible for these events. Various molecular pathways and numerous mediators have been found to be involved in the intricate process of regulating blood-brain barrier permeability following traumatic brain injury. This review provides an update to the existing knowledge about the various pathophysiological pathways and advancements in the field of blood-brain barrier dysfunction and hyperpermeability following traumatic brain injury, including the role of various tight junction proteins involved in blood-brain barrier integrity and regulation. We also address pitfalls of existing systems and propose strategies to improve the various debilitating functional deficits caused by this progressive epidemic.

Treatment of traumatic brain injury with anti-inflammatory drugs

Traumatic brain injury rapidly induces inflammation. This inflammation is produced both by endogenous brain cells and circulating inflammatory cells that enter from the brain. Together they drive the inflammatory response through a wide variety of bioactive lipids, cytokines and chemokines. A large number of drugs with anti-inflammatory action have been tested in both preclinical studies and in clinical trials. These drugs either have known anti-inflammatory action or inhibit the inflammatory response through unknown mechanisms. The results of these preclinical studies and clinical trials are reviewed. Recommendations are suggested on how to improve preclinical testing of drugs to make them more relevant to evaluate for clinical trials.

A single dose of PPARγ agonist pioglitazone reduces cortical oxidative damage and microglial reaction following lateral fluid percussion brain injury in rats

Neuroprotective actions of the peroxisome proliferator-activated receptor-γ (PPARγ) agonists have been observed in various animal models of the brain injuries. In this study we examined the effects of a single dose of pioglitazone on oxidative and inflammatory parameters as well as on neurodegeneration and the edema formation in the rat parietal cortex following traumatic brain injury (TBI) induced by the lateral fluid percussion injury (LFPI) method. Pioglitazone was administered in a dose of 1mg/kg at 10min after the brain trauma. The animals of the control group were sham-operated and injected by vehicle. The rats were decapitated 24h after LFPI and their parietal cortices were analyzed by biochemical and histological methods. Cortical edema was evaluated in rats sacrificed 48h following TBI. Brain trauma caused statistically significant oxidative damage of lipids and proteins, an increase of glutathione peroxidase (GSH-Px) activity, the cyclooxygenase-2 (COX-2) overexpression, reactive astrocytosis, the microglia activation, neurodegeneration, and edema, but it did not influence the superoxide dismutase activity and the expressions of interleukin-1 beta, interleukin-6 and tumor necrosis factor-alpha in the rat parietal cortex. Pioglitazone significantly decreased the cortical lipid and protein oxidative damage, increased the GSH-Px activity and reduced microglial reaction. Although a certain degree of the TBI-induced COX-2 overexpression, neurodegeneration and edema decrease was detected in pioglitazone treated rats, it was not significant. In the injured animals, cortical reactive astrocytosis was unchanged by the tested PPARγ agonist. These findings demonstrate that pioglitazone, administered only in a single dose, early following LFPI, reduced cortical oxidative damage, increased antioxidant defense and had limited anti-inflammatory effect, suggesting the need for further studies of this drug in the treatment of TBI.

Meloxicam inhibits fipronil-induced apoptosis via modulation of the oxidative stress and inflammatory response in SH-SY5Y cells

Oxidative stress and inflammatory responses have been identified as key elements of neuronal cell apoptosis. In this study, we investigated the mechanisms by which inflammatory responses contribute to apoptosis in human neuroblastoma SH-SY5Y cells treated with fipronil (FPN). Based on the cytotoxic mechanism of FPN, we examined the neuroprotective effects of meloxicam against FPN-induced neuronal cell death. Treatment of SH-SY5Y cells with FPN induced apoptosis via activation of caspase-9 and -3, leading to nuclear condensation. In addition, FPN induced oxidative stress and increased expression of cyclooxygenase-2 (COX-2) and tumor necrosis factor-α (TNF-α) via inflammatory stimulation. Pretreatment of cells with meloxicam enhanced the viability of FPN-exposed cells through attenuation of oxidative stress and inflammatory response. FPN activated mitogen activated protein kinase (MAPK) and inhibitors of MAPK abolished FPN-induced COX-2 expression. Meloxicam also attenuated FPN-induced cell death by reducing MAPK-mediated pro-inflammatory factors. Furthermore, we observed both nuclear accumulation of p53 and enhanced levels of cytosolic p53 in a concentration-dependent manner after FPN treatment. Pretreatment of cells with meloxicam blocked the translocation of p53 from the cytosol to the nucleus. Together, these data suggest that meloxicam may exert anti-apoptotic effects against FPN-induced cytotoxicity by both attenuating oxidative stress and inhibiting the inflammatory cascade via inactivation of MAPK and p53 signaling.

Methamphetamine effects on blood-brain barrier structure and function

Methamphetamine (Meth) is a widely abuse psychostimulant. Traditionally, studies have focused on the neurotoxic effects of Meth on monoaminergic neurotransmitter terminals. Recently, both in vitro and in vivo studies have investigated the effects of Meth on the BBB and found that Meth produces a decrease in BBB structural proteins and an increase in BBB permeability to various molecules. Moreover, preclinical studies are validated by clinical studies in which human Meth users have increased concentrations of toxins in the brain. Therefore, this review will focus on the structural and functional disruption of the BBB caused by Meth and the mechanisms that contribute to Meth-induced BBB disruption. The review will reveal that the mechanisms by which Meth damages dopamine and serotonin terminals are similar to the mechanisms by which the blood-brain barrier (BBB) is damaged. Furthermore, this review will cover the factors that are known to potentiate the effects of Meth (McCann et al., 1998) on the BBB, such as stress and HIV, both of which are co-morbid conditions associated with Meth abuse. Overall, the goal of this review is to demonstrate that the scope of damage produced by Meth goes beyond damage to monoaminergic neurotransmitter systems to include BBB disruption as well as provide a rationale for investigating therapeutics to treat Meth-induced BBB disruption. Since a breach of the BBB can have a multitude of consequences, therapies directed toward the treatment of BBB disruption may help to ameliorate the long-term neurodegeneration and cognitive deficits produced by Meth and possibly even Meth addiction.

WITHDRAWN: Riluzole alleviates early neutrophil infiltration, brain oedema and lipid peroxidation in the traumatic brain tissue but does not induce neurotoxicity in non-traumatic brain tissue in rats

This article has been withdrawn at the request of the editor since, in breach of ethical guidelines and journal policies, the manuscript was submitted without the full knowledge and consent of all authors listed. The Publisher apologizes for any inconvenience this may cause. The full Elsevier Policy on Article Withdrawal can be found at http://www.elsevier.com/locate/withdrawalpolicy.

Transport rankings of non-steroidal antiinflammatory drugs across blood-brain barrier in vitro models

The aim of this work was to conduct a comprehensive study about the transport properties of NSAIDs across the blood-brain barrier (BBB) in vitro. Transport studies with celecoxib, diclofenac, ibuprofen, meloxicam, piroxicam and tenoxicam were accomplished across Transwell models based on cell line PBMEC/C1-2, ECV304 or primary rat brain endothelial cells. Single as well as group substance studies were carried out. In group studies substance group compositions, transport medium and serum content were varied, transport inhibitors verapamil and probenecid were added. Resulted permeability coefficients were compared and normalized to internal standards diazepam and carboxyfluorescein. Transport rankings of NSAIDs across each model were obtained. Single substance studies showed similar rankings as corresponding group studies across PBMEC/C1-2 or ECV304 cell layers. Serum content, glioma conditioned medium and inhibitors probenecid and verapamil influenced resulted permeability significantly. Basic differences of transport properties of the investigated NSAIDs were similar comparing all three in vitro BBB models. Different substance combinations in the group studies and addition of probenecid and verapamil suggested that transporter proteins are involved in the transport of every tested NSAID. Results especially underlined the importance of same experimental conditions (transport medium, serum content, species origin, cell line) for proper data comparison.

Neuronal and nonneuronal COX-2 expression confers neurotoxic and neuroprotective phenotypes in response to excitotoxin challenge

Treating acute brain injuries with COX-2 inhibitors can produce both neuroprotective and neurotoxic effects. This study investigated the role of COX-2 in modulating acute brain injury induced by excitotoxic neural damage. Intrastriatal injection of excitotoxin (RS)-(tetrazole-5yl) glycine elicited COX-2 expression in two distinct groups of cells. cortical neurons surrounding the lesion and vascular cells in the lesion core. The vascular COX-2 was expressed in two cell types, endothelial cells and monocytes. Selective deletion of COX-2 in vascular cells in Tie2Cre Cox-2(flox/flox) mice did not affect the induction of COX-2 in neurons after the excitotoxin injection but resulted in increased lesion volume, indicating a neuroprotective role for the COX-2 expressed in the vascular cells. Selective deletion of monocyte COX-2 in LysMCre Cox-2(flox/flox) mice did not reduce COX-2-dependent neuroprotection, suggesting that endothelial COX-2 is sufficient to confer neuroprotection. Pharmacological inhibition of COX-2 activity in Tie2Cre Cox-2(flox/flox) mice reduced lesion volume, indicating a neurotoxic role for the COX-2 expressed in neurons. Furthermore, COX-2-dependent neurotoxicity was mediated, at least in part, via the activation of the EP1 receptor. These results show that Cox-2 expression induced in different cell types can confer opposite effects.

The anti-inflammatory drug carprofen improves long-term outcome and induces gliogenesis after traumatic brain injury

Traumatic brain injury (TBI) initiates acute and chronic inflammatory processes involving cyclooxygenase-2 (COX-2), which may have detrimental effects on outcome and especially on brain regeneration. Therefore we aimed to study whether carprofen, a COX-2 inhibitor, would improve outcome and increase neurogenesis after TBI. TBI was induced in Sabra mice that were then treated with vehicle or carprofen for 7 days. Functional outcome was evaluated with the Neurological Severity Score (NSS).Cytokine levels were assessed 4 h post-TBI and water content was measured 24 h post TBI. Mice were given BrdU to label newborn cells for 10 days. The animals were killed 90 days post-TBI and the lesion size as well as newborn cell fate were assessed. Carprofen significantly reduced lesion size (p=0.002), decreased water content in the lesioned cortex (p=0.03), reduced the number of microglia in the lesioned cortex (p<0.0001), and lowered the levels of proinflammatory cytokines (IL-1β, p=0.03; IL-6, p=0.02). Carprofen led to significantly larger improvements in functional outcome (p≤0.008) which were durable over 90 days. Carprofen also induced a threefold increase in the proliferation of new cells in the peri-lesion area (p≤0.002), but newborn cells differentiated mainly into glia in both groups. Carprofen is neuroprotective and induces cell proliferation and gliogenesis after TBI. Treatment with carprofen is consistently associated with better functional outcome. Our results imply that anti-inflammatory drugs may represent novel therapeutic options for TBI.

Meloxicam exerts neuroprotection on spinal cord trauma in rats

Traumatic injury to the central nervous system results in the delayed dysfunction and neuronal death. Impaired mitochondrial function, generation of reactive oxygen species (ROS), and lipid peroxidation occur soon after traumatic spinal cord injury (SCI), while the activation of compensatory molecules that neutralize ROS occurs at later time points. The aim of the current study was to investigate the putative neuroprotective effect of the COX2 inhibitor meloxicam in a rat model of SCI. In order to induce SCI, a standard weight-drop method that induced a moderately severe injury (100 g/cm force) at T10, was used. Injured animals were given either 2 mg/kg meloxicam or saline 30 min postinjury by intraperitoneal injection. At seven days postinjury, neurological examination was performed and rats were decapitated. Spinal cord samples were taken for histological examination or determination of malondialdehyde (MDA) and glutathione (GSH) levels, myeloperoxidase (MPO) activity and DNA fragmentation. Formation of ROS in spinal cord tissue samples was monitored by using a chemiluminescence (CL) technique. SCI caused a significant decrease in spinal cord GSH content, which was accompanied with significant increases in CL, MDA levels, MPO activity, and DNA damage. On the other hand, meloxicam treatment reversed all these biochemical parameters as well as SCI-induced histopathological alterations. Furthermore, impairment of the neurological functions due to SCI was improved by meloxicam treatment. The present study suggests that meloxicam, reduces SCI-induced oxidative stress and exerts neuroprotection by inhibiting lipid peroxidation, GSH depletion, and DNA fragmentation.