Anti-inflammatory effects of chronic aspirin on brain arachidonic acid metabolites

Adjunctive Aspirin vs Placebo in Patients With Schizophrenia: Results of Two Randomized Controlled Trials

Two previous randomized controlled trials (RCTs) suggested that adjunctive aspirin is efficacious in treating schizophrenia. We conducted two 16-week double-blind randomized placebo-controlled RCTs of adjunctive 1000 mg aspirin vs placebo in schizophrenia. Study 1 included 200 patients, with Positive and Negative Syndrome Scale (PANSS) total score as the primary outcome. Study 2 included 160 patients with C-reactive protein (CRP) >1 mg/L at baseline; the primary outcome was PANSS-positive score. Dropout rates for aspirin/placebo were 12% in study 1 and 20% in study 2. Differences in outcome between aspirin and placebo were calculated with linear regression, adjusting for the baseline value of the outcome. No statistically significant between-group differences were found in primary or secondary outcomes in either study. Study 1: mean difference in PANSS at 16 weeks was -3.9 (95% CI: -8.4 to 0.5, P = .10, effect size (ES) = -0.25) and at 8 weeks was -3.5 (95% CI: -7.5 to 0.5, P = .11, ES = -0.22). Study 2: mean difference in PANSS at 16 weeks was 0.3 (95% CI: -4.1 to 4.7, P = .90, ES = 0.02) and in positive PANSS was 0.5 (95% CI: -1.0 to 2.1, P = .50, ES = 0.11). A meta-analysis of these data with the existing studies, excluding one with large baseline differences in total PANSS, found that the overall estimate of the effect of adjunctive aspirin on the PANSS total score comparing group means at the end of the study was -2.9 (95% CI: -6.6 to 0.7; P = .21), favoring aspirin. Our studies and meta-analysis failed to find a statistically significant improvement in the symptoms of schizophrenia from adjunctive aspirin therapy in comparison to placebo in schizophrenia. Trial registration: study 1: Clinicaltrials.gov: NCT01320982; study 2 (high CRP): EudraCT Number: 2014-000757-36.

Multi-pathway integrated adjustment mechanism of licorice flavonoids presenting anti-inflammatory activity

Glycyrrhiza, commonly known as licorice, is a herbal medicine that has been used for thousands of years. Licorice contains multiple flavonoids, which possess a variety of biological activities. On the basis of the anti-inflammatory effects of licorice flavonoids, the potential mechanism of action was investigated via a plasma metabolomics approach. A total of 9 differential endogenous metabolites associated with the therapeutic effect of licorice flavonoids were identified, including linoleic acid, sphingosine, tryptophanamide, corticosterone and leukotriene B4. Besides classical arachidonic acid metabolism, metabolism of sphingolipids, tryptophan and fatty acids, phospholipids synthesis, and other pathways were also involved. The multi-pathway integrated adjustment mechanism of licorice flavonoid action may reduce side effects in patients, along with any anti-inflammatory functions, which provides a foundation for identifying and developing novel, high-potential natural drugs with fewer side effects for clinical application.

Microarray analysis of gene expression in the cyclooxygenase knockout mice - a connection to autism spectrum disorder

The cellular and molecular events that take place during brain development play an important role in governing function of the mature brain. Lipid-signalling molecules such as prostaglandin E₂ (PGE₂ ) play an important role in healthy brain development. Abnormalities along the COX-PGE₂ signalling pathway due to genetic or environmental causes have been linked to autism spectrum disorder (ASD). This study aims to evaluate the effect of altered COX-PGE₂ signalling on development and function of the prenatal brain using male mice lacking cyclooxygenase-1 and cyclooxygenase-2 (COX-1^-/- and COX-2^-/- ) as potential model systems of ASD. Microarray analysis was used to determine global changes in gene expression during embryonic days 16 (E16) and 19 (E19). Gene Ontology: Biological Process (GO:BP) and Kyoto Encyclopedia of Genes and Genomes (KEGG) were implemented to identify affected developmental genes and cellular processes. We found that in both knockouts the brain at E16 had nearly twice as many differentially expressed genes, and affected biological pathways containing various ASD-associated genes important in neuronal function. Interestingly, using GeneMANIA and Cytoscape we also show that the ASD-risk genes identified in both COX-1^-/- and COX-2^-/- models belong to protein-interaction networks important for brain development despite of different cellular localization of these enzymes. Lastly, we identified eight genes that belong to the Wnt signalling pathways exclusively in the COX-2^-/- mice at E16. The level of PKA-phosphorylated β-catenin (S552), a major activator of the Wnt pathway, was increased in this model, suggesting crosstalk between the COX-2-PGE₂ and Wnt pathways during early brain development. Overall, these results provide further molecular insight into the contribution of the COX-PGE₂ pathways to ASD and demonstrate that COX-1^-/- and COX-2^-/- animals might be suitable new model systems for studying the disorders.

Effect of tocopherol and acetylsalicylic acid on the biochemical indices of blood in dioxin-exposed rats

New sources of dioxins and increased dioxin concentrations in the environment, coupled with their increased bioavailability along the food chain and accumulation in adipose tissues, contribute to various adverse long-term biological effects. The purpose of the study was to determine whether tocopherol protects the CNS by decreasing the pro-inflammatory influence of free radicals generated by TCDD; whether acetylsalicylic acid inhibits the production of inflammatory mediators; and whether the combined administration of tocopherol and acetylsalicylic acid to TCDD-exposed rats has a potential CNS-protective effect. The study included 117 rats divided into 8 groups: 75 female and 12 male Buffalo rats aged 8-10 weeks, weighing 140-160 g; as well as 30 female rats aged 6 weeks and weighing 120 g, which were the offspring of females from each study group. In the experiment, the following substances were used: 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), dosed at 5 μg/kg BW and 12.5 μg/kg BW, diluted in a 1% DMSO solution at the concentration of 1 μg/ml; α-tocopherol acetate, dosed at 30 mg/kg BW, in 0.2 ml of oil solution; and acetylsalicylic acid, 50mg/kg BW, suspended in 0.5 ml of starch solution, administered orally using a feeding tube. Pleurisy was induced by an injection of 0.15 ml of 1% carrageenin solution. The use of tocopherol reduces the adverse effects of the inflammatory reaction induced by TCDD. Administering tocopherol improves protein metabolism by reducing protein catabolism, and raises γ-globulin fraction levels. Combined acetylsalicylic acid and tocopherol suppress catabolic processes accompanying inflammation.

Aspirin Inhibits Degenerative Changes of Aneurysmal Wall in a Rat Model

Aneurysmal subarachnoid hemorrhage still has a high mortality and morbidity despite notable advances in surgical approaches to cerebral aneurysm (CA). We examined the role of aspirin in vascular inflammation and degeneration. CA was induced in male Sprague-Dawley rats by ligating left common carotid artery and bilateral posterior renal arteries with or without aspirin treatment. The right anterior cerebral artery/olfactory artery (ACA/OA) bifurcations were stripped and assessed morphologically after Verhoeff's Van Gieson staining. Blood sample was obtained to examine circulating CD34(+) CD133(+) endothelial progenitor cells (EPCs), platelet aggregation and platelet counts. Macrophages infiltration in aneurysmal wall was evaluated by immunohistochemistry. Expression of matrix metalloproteinase-2 and 9 (MMP-2 and 9), nuclear factor kappa B (NF-κB), macrophage chemoattractant protein-1 (MCP-1) and vascular cell adhesion molecule-1 (VCAM-1) was examined by RT-PCR. 2 months after CA induction, surgically treated rats manifested aneurysmal degeneration in ACA/OA bifurcations. Aspirin-treated rats exhibited a significant decrease in degradation of internal elastic lamina (IEL), medial layer thinning, CA size and macrophages infiltration with reduced expression of MMP-2 and 9 compared with rats in the CA group. RT-PCR demonstrated that the upregulation of NF-κB, MCP-1 and VCAM-1 after CA induction was reversed by aspirin treatment. Aspirin treatment following CA induction increased circulating EPCs to near control levels and reduced platelet aggregation without changing platelet counts. The evidence suggested that aspirin significantly reduced degeneration of aneurysm walls by inhibiting macrophages-mediated chronic inflammation and mobilizing EPCs.

Histopathological, ultrastructural, and immunohistochemical assessment of hippocampus structures of rats exposed to TCDD and high doses of tocopherol and acetylsalicylic acid

The effect of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) on central nervous system consists of changing expression of estrogen receptors, whereas the result of chronic inflammatory reaction caused by dioxin is occurrence of destructive changes in various organs connected with disturbed metabolism of connective tissue and damage of cells. The aim of the study was to determine the effect of dioxins on function, ultrastructure, and cytological and histological structure of hippocampus, particularly on expression of estrogen receptors in central nervous system as well as to define protective influence of tocopherol (TCP) and acetylsalicylic acid (ASA) on the decrease in activity of proinflammatory effects in central nervous system. It was shown that TCDD contributes to destructive and inflammatory changes along with demyelization of myelin sheaths and atrophy of estrogen receptors in hippocampus. Dioxin contributes to atrophy of estrogen receptors in hippocampus, in which also destructive and inflammatory changes were found along with demyelination of myelin sheaths. Histopathological and ultrastructural image of hippocampus areas in rats, in which both TCP and ASA were used, is characterized by poorly expressed degenerative changes and smaller inflammatory reactivity. Using both TCP and ASA has a protective effect on functions of central nervous system.

Inflammation, Cancer and Oxidative Lipoxygenase Activity are Intimately Linked

Cancer and inflammation are intimately linked due to specific oxidative processes in the tumor microenvironment. Lipoxygenases are a versatile class of oxidative enzymes involved in arachidonic acid metabolism. An increasing number of arachidonic acid metabolites is being discovered and apart from their classically recognized pro-inflammatory effects, anti-inflammatory effects are also being described in recent years. Interestingly, these lipid mediators are involved in activation of pro-inflammatory signal transduction pathways such as the nuclear factor κB (NF-κB) pathway, which illustrates the intimate link between lipid signaling and transcription factor activation. The identification of the role of arachidonic acid metabolites in several inflammatory diseases led to a significant drug discovery effort around arachidonic acid metabolizing enzymes. However, to date success in this area has been limited. This might be attributed to the lack of selectivity of the developed inhibitors and to a lack of detailed understanding of the functional roles of arachidonic acid metabolites in inflammatory responses and cancer. This calls for a more detailed investigation of the activity of arachidonic acid metabolizing enzymes and development of more selective inhibitors.

Acetylsalicylic acid and ascorbic acid combination improves cognition; via antioxidant effect or increased expression of NMDARs and nAChRs?

Chronic inflammation occurs systematically in the central nervous system during ageing, it has been shown that neuroinflammation plays an important role in the pathogenesis of many neurodegenerative disorders. Aspirin, a nonselective COX inhibitor, as well as ascorbic acid, has been purported to protect cerebral tissue. We investigated the effects of subchronic aspirin and ascorbic acid usage on spatial learning, oxidative stress and expressions of NR2A, NR2B, nAChRα7, α4 and β2. Forty male rats (16-18 months) were divided into 4 groups, namely, control, aspirin-treated, ascorbic acid-treated, aspirin+ascorbic acid-treated groups. Following 10-weeks administration period, rats were trained and tested in the Morris water maze. 8-Hydroxy-2-deoxyguanosine and malondialdehyde were evaluated by ELISA and HPLC, respectively. Receptor expressions were assessed by western blotting of hippocampi. Spatial learning performance improved partially in the aspirin group, but significant improvement was seen in the aspirin+ascorbic acid group (p < 0.05). While 8-hydroxy-2-deoxyguanosine and malondialdehyde levels were significantly decreased, NR2B and nAChRα7 expressions were significantly increased in the aspirin+ascorbic acid group as compared to the control group (p < 0.05). Subchronic treatment with aspirin+ascorbic acid in aged rats was shown to enhance cognitive performance and increase the expressions of several receptors related to learning and memory process.

Dactyloditerpenol acetate, a new prenylbisabolane-type diterpene from Aplysia dactylomela with significant in vitro anti-neuroinflammatory activity

A new regular diterpene possessing an unusual 1,6-anti-3-methylcyclohex-2-en-1-ol ring system, dactyloditerpenol acetate (1), has been extracted from the tropical sea hare Aplysia dactylomela and its stereostructure elucidated by spectroscopic methods. The absolute configuration of 1 was determined as 1S, 6S, 7R, 10S, and 11R by application of Kishi's method for the assignment of absolute configuration of alcohols. The new diterpene potently inhibited in vitro thromboxane B2 (TXB2) (IC50 0.4μM) and superoxide anion (O2(-)) (IC50 1μM) generation from Escherichia coli lipopolysaccharide (LPS)-activated rat neonatal microglia, with concomitant low short-term toxicity.

Neuroinflammation: the role and consequences

Neuroinflammation is central to the common pathology of several acute and chronic brain diseases. This review examines the consequences of excessive and prolonged neuroinflammation, particularly its damaging effects on cellular and/or brain function, as well as its relevance to disease progression and possible interventions. The evidence gathered here indicates that neuroinflammation causes and accelerates long-term neurodegenerative disease, playing a central role in the very early development of chronic conditions including dementia. The wide scope and numerous complexities of neuroinflammation suggest that combinations of different preventative and therapeutic approaches may be efficacious.

Unesterified docosahexaenoic acid is protective in neuroinflammation

Docosahexaenoic acid (22:6n-3) is the major brain n-3 polyunsaturated fatty acid and it is possible that docosahexaenoic acid is anti-inflammatory in the brain as it is known to be in other tissues. Using a combination of models including the fat-1 transgenic mouse, chronic dietary n-3 polyunsaturated fatty acid modulation in transgenic and wild-type mice, and acute direct brain infusion, we demonstrated that unesterified docosahexaenoic acid attenuates neuroinflammation initiated by intracerebroventricular lipopolysaccharide. Hippocampal neuroinflammation was assessed by gene expression and immunohistochemistry. Furthermore, docosahexaenoic acid protected against lipopolysaccharide-induced neuronal loss. Acute intracerebroventricular infusion of unesterified docosahexaenoic acid or its 12/15-lipoxygenase product and precursor to protectins and resolvins, 17S-hydroperoxy-docosahexaenoic acid, mimics anti-neuroinflammatory aspects of chronically increased unesterified docosahexaenoic acid. LC-MS/MS revealed that neuroprotectin D1 and several other docosahexaenoic acid-derived specialized pro-resolving mediators are present in the hippocampus. Acute intracerebroventricular infusion of 17S-hydroperoxy-docosahexaenoic acid increases hippocampal neuroprotectin D1 levels concomitant to attenuating neuroinflammation. These results show that unesterified docosahexaenoic acid is protective in a lipopolysaccharide-initiated mouse model of acute neuroinflammation, at least in part, via its conversion to specialized pro-resolving mediators; these docosahexaenoic acid stores may provide novel targets for the prevention and treatment(s) of neurological disorders with a neuroinflammatory component. Our study shows that chronically increased brain unesterified DHA levels, but not solely phospholipid DHA levels, attenuate neuroinflammation. Similar attenuations occur with acute increases in brain unesterified DHA or 17S-HpDHA levels, highlighting the importance of an available pool of precursor unesterified DHA for the production of enzymatically derived specialized pro-resolving mediators that are critical in the regulation of neuroinflammation.

RETRACTED: Increased neuroinflammatory and arachidonic acid cascade markers, and reduced synaptic proteins, in the postmortem frontal cortex from schizophrenia patients

This article has been retracted: please see Elsevier Policy on Article Withdrawal (https://www.elsevier.com/about/our-business/policies/article-withdrawal). This article has been retracted at the request of the Editors. The National Institutes of Health has found that Dr. Jagadeesh S. Rao engaged in research misconduct by falsifying data. Data in Figures 1A, 1E, 3E and 3F were falsified. Dr. Rao was solely responsible for the falsification. None of the other authors are implicated in any way.

Dose-dependent changes in neuroinflammatory and arachidonic acid cascade markers with synaptic marker loss in rat lipopolysaccharide infusion model of neuroinflammation

Background

Neuroinflammation, caused by six days of intracerebroventricular infusion of bacterial lipopolysaccharide (LPS), stimulates rat brain arachidonic acid (AA) metabolism. The molecular changes associated with increased AA metabolism are not clear. We examined effects of a six-day infusion of a low-dose (0.5 ng/h) and a high-dose (250 ng/h) of LPS on neuroinflammatory, AA cascade, and pre- and post-synaptic markers in rat brain. We used artificial cerebrospinal fluid-infused brains as controls.

Results

Infusion of low- or high-dose LPS increased brain protein levels of TNFα, and iNOS, without significantly changing GFAP. High-dose LPS infusion upregulated brain protein and mRNA levels of AA cascade markers (cytosolic cPLA₂-IVA, secretory sPLA₂-V, cyclooxygenase-2 and 5-lipoxygenase), and of transcription factor NF-κB p50 DNA binding activity. Both LPS doses increased cPLA₂ and p38 mitogen-activated protein kinase levels, while reducing protein levels of the pre-synaptic marker, synaptophysin. Post-synaptic markers drebrin and PSD95 protein levels were decreased with high- but not low-dose LPS.

Conclusions

Chronic LPS infusion has differential effects, depending on dose, on inflammatory, AA and synaptic markers in rat brain. Neuroinflammation associated with upregulated brain AA metabolism can lead to synaptic dysfunction.

Chronic inflammatory diseases are stimulated by current lifestyle: how diet, stress levels and medication prevent our body from recovering

Serhan and colleagues introduced the term "Resoleomics" in 1996 as the process of inflammation resolution. The major discovery of Serhan's work is that onset to conclusion of an inflammation is a controlled process of the immune system (IS) and not simply the consequence of an extinguished or "exhausted" immune reaction. Resoleomics can be considered as the evolutionary mechanism of restoring homeostatic balances after injury, inflammation and infection. Under normal circumstances, Resoleomics should be able to conclude inflammatory responses. Considering the modern pandemic increase of chronic medical and psychiatric illnesses involving chronic inflammation, it has become apparent that Resoleomics is not fulfilling its potential resolving capacity. We suggest that recent drastic changes in lifestyle, including diet and psycho-emotional stress, are responsible for inflammation and for disturbances in Resoleomics. In addition, current interventions, like chronic use of anti-inflammatory medication, suppress Resoleomics. These new lifestyle factors, including the use of medication, should be considered health hazards, as they are capable of long-term or chronic activation of the central stress axes. The IS is designed to produce solutions for fast, intensive hazards, not to cope with long-term, chronic stimulation. The never-ending stress factors of recent lifestyle changes have pushed the IS and the central stress system into a constant state of activity, leading to chronically unresolved inflammation and increased vulnerability for chronic disease. Our hypothesis is that modern diet, increased psycho-emotional stress and chronic use of anti-inflammatory medication disrupt the natural process of inflammation resolution ie Resoleomics.

Imaging brain signal transduction and metabolism via arachidonic and docosahexaenoic acid in animals and humans

The polyunsaturated fatty acids (PUFAs), arachidonic acid (AA, 20:4n-6) and docosahexaenoic acid (DHA, 22:6n-3), important second messengers in brain, are released from membrane phospholipid following receptor-mediated activation of specific phospholipase A(2) (PLA(2)) enzymes. We developed an in vivo method in rodents using quantitative autoradiography to image PUFA incorporation into brain from plasma, and showed that their incorporation rates equal their rates of metabolic consumption by brain. Thus, quantitative imaging of unesterified plasma AA or DHA incorporation into brain can be used as a biomarker of brain PUFA metabolism and neurotransmission. We have employed our method to image and quantify effects of mood stabilizers on brain AA/DHA incorporation during neurotransmission by muscarinic M(1,3,5), serotonergic 5-HT(2A/2C), dopaminergic D(2)-like (D(2), D(3), D(4)) or glutamatergic N-methyl-d-aspartic acid (NMDA) receptors, and effects of inhibition of acetylcholinesterase, of selective serotonin and dopamine reuptake transporter inhibitors, of neuroinflammation (HIV-1 and lipopolysaccharide) and excitotoxicity, and in genetically modified rodents. The method has been extended for the use with positron emission tomography (PET), and can be employed to determine how human brain AA/DHA signaling and consumption are influenced by diet, aging, disease and genetics.

Increased neuroinflammatory and arachidonic acid cascade markers, and reduced synaptic proteins, in brain of HIV-1 transgenic rats

Background

Cognitive impairment has been reported in human immune deficiency virus-1- (HIV-1-) infected patients as well as in HIV-1 transgenic (Tg) rats. This impairment has been linked to neuroinflammation, disturbed brain arachidonic acid (AA) metabolism, and synapto-dendritic injury. We recently reported upregulated brain AA metabolism in 7- to 9-month-old HIV-1 Tg rats. We hypothesized that these HIV-1 Tg rats also would show upregulated brain inflammatory and AA cascade markers and a deficit of synaptic proteins.

Methods

We measured protein and mRNA levels of markers of neuroinflammation and the AA cascade, as well as pro-apoptotic factors and synaptic proteins, in brains from 7- to 9-month-old HIV-1 Tg and control rats.

Results

Compared with control brain, HIV-1 Tg rat brain showed immunoreactivity to glycoprotein 120 and tat HIV-1 viral proteins, and significantly higher protein and mRNA levels of (1) the inflammatory cytokines interleukin-1β and tumor necrosis factor α, (2) the activated microglial/macrophage marker CD11b, (3) AA cascade enzymes: AA-selective Ca²⁺-dependent cytosolic phospholipase A₂ (cPLA₂)-IVA, secretory sPLA₂-IIA, cyclooxygenase (COX)-2, membrane prostaglandin E₂ synthase, 5-lipoxygenase (LOX) and 15-LOX, cytochrome p450 epoxygenase, and (4) transcription factor NF-κBp50 DNA binding activity. HIV-1 Tg rat brain also exhibited signs of cell injury, including significantly decreased levels of brain-derived neurotrophic factor (BDNF) and drebrin, a marker of post-synaptic excitatory dendritic spines. Expression of Ca²⁺-independent iPLA₂-VIA and COX-1 was unchanged.

Conclusions

HIV-1 Tg rats show elevated brain markers of neuroinflammation and AA metabolism, with a deficit in several synaptic proteins. These changes are associated with viral proteins and may contribute to cognitive impairment. The HIV-1 Tg rat may be a useful model for understanding progression and treatment of cognitive impairment in HIV-1 patients.