[Show description][Hide description] DESCRIPTION: Background: The acylethanolamides oleoylethanolamide and palmitoylethanolamide are endogenous lipid mediators with
proposed neuroprotectant properties in central nervous system (CNS) pathologies. The precise mechanisms remain partly
unknown, but growing evidence suggests an antiinflammatory/antioxidant profile.
Methods: We tested whether oleoylethanolamide/palmitoylethanolamide (10mg/kg, i.p.) attenuate neuroinflammation
and acute phase responses (hypothalamus-pituitary-adrenal (HPA) stress axis stress axis activation, thermoregulation, and
anhedonia) induced by lipopolysaccharide (0.5mg/kg, i.p.) in rats.
Results: Lipopolysaccharide increased mRNA levels of the proinflammatory cytokines tumor necrosis factor-α, interleukin-
1β, and interleukin-6, nuclear transcription factor-κB activity, and the expression of its inhibitory protein IκBα in cytoplasm,
the inducible isoforms of nitric oxide synthase and cyclooxygenase-2, microsomal prostaglandin E2
synthase mRNA, and
proinflammatory prostaglandin E2
content in frontal cortex 150 minutes after administration. As a result, the markers of
nitrosative/oxidative stress nitrites (NO2
) and malondialdehyde were increased. Pretreatment with oleoylethanolamide/
palmitoylethanolamide reduced plasma tumor necrosis factor-α levels after lipopolysaccharide, but only oleoylethanolamide
significantly reduced brain tumor necrosis factor-α mRNA. Oleoylethanolamide and palmitoylethanolamide prevented
lipopolysaccharide-induced nuclear transcription factor-κB (NF-κB)/IκBα upregulation in nuclear and cytosolic extracts,
respectively, the expression of inducible isoforms of nitric oxide synthase, cyclooxygenase-2, and microsomal prostaglandin
synthase and the levels of prostaglandin E2
. Additionally, both acylethanolamides reduced lipopolysaccharide-induced
[Show abstract][Hide abstract] ABSTRACT: Among etiological explanations for psychosis, several hypotheses involving alterations on the immune/inflammatory system have been proposed. The endocannabinoid system (ECS) is an endogenous neuroprotective, anti-inflammatory system that modulates cognitive processes. Its altered expression has been associated with psychotic disorders. 73 patients with a first episode of psychoses (FEP) and 67 healthy controls were recruited in 5 university centers in Spain. The protein expression of the main peripheral ECS components was determined in peripheral blood mononuclear cells. The cognition function was assessed following the MATRICS consensus. After controlling for potential confounding factors, working memory statistically correlated to the peripheral N-acyl phosphatidylethanolamine phospholipase expression (p = 0.039). The short-term verbal memory correlated to the Diacylglycerol lipase (p = 0.043) and the fatty acid amide hydrolase (p = 0.026) expression. Finally, attention measures correlated to the Monoacylglycerol lipase expression, by means of the CPT-II commissions (p = 0.036) and detectability (p = 0.026) scores. The ECS may regulate the activation of key mediators in immune and inflammatory responses that may be involved in the primary neuronal stress phenomenon that occurs from the onset of psychotic illness. This study points a relationship between the ECS and the cognitive function in early psychosis and suggests the use of some of the ECS elements as biomarkers and/or pharmacological targets for FEP.
No preview · Article · Jan 2016 · Journal of Psychiatric Research
[Show abstract][Hide abstract] ABSTRACT: Background:
Late onset bipolar disorder (LOBD) is often difficult to distinguish from degenerative dementias, such as Alzheimer disease (AD), due to comorbidities and common cognitive symptoms. Moreover, LOBD prevalence in the elder population is not negligible and it is increasing. Both pathologies share pathophysiological neuroinflammation features. Improvements in differential diagnosis of LOBD and AD will help to select the best personalized treatment.
The aim of this study is to assess the relative significance of clinical observations, neuropsychological tests, and specific blood plasma biomarkers (inflammatory and neurotrophic), separately and combined, in the differential diagnosis of LOBD versus AD. It was carried out evaluating the accuracy achieved by classification-based computer-aided diagnosis (CAD) systems based on these variables.
A sample of healthy controls (HC) (n = 26), AD patients (n = 37), and LOBD patients (n = 32) was recruited at the Alava University Hospital. Clinical observations, neuropsychological tests, and plasma biomarkers were measured at recruitment time.
We applied multivariate machine learning classification methods to discriminate subjects from HC, AD, and LOBD populations in the study. We analyzed, for each classification contrast, feature sets combining clinical observations, neuropsychological measures, and biological markers, including inflammation biomarkers. Furthermore, we analyzed reduced feature sets containing variables with significative differences determined by a Welch's t-test. Furthermore, a battery of classifier architectures were applied, encompassing linear and non-linear Support Vector Machines (SVM), Random Forests (RF), Classification and regression trees (CART), and their performance was evaluated in a leave-one-out (LOO) cross-validation scheme. Post hoc analysis of Gini index in CART classifiers provided a measure of each variable importance.
Welch's t-test found one biomarker (Malondialdehyde) with significative differences (p < 0.001) in LOBD vs. AD contrast. Classification results with the best features are as follows: discrimination of HC vs. AD patients reaches accuracy 97.21% and AUC 98.17%. Discrimination of LOBD vs. AD patients reaches accuracy 90.26% and AUC 89.57%. Discrimination of HC vs LOBD patients achieves accuracy 95.76% and AUC 88.46%.
It is feasible to build CAD systems for differential diagnosis of LOBD and AD on the basis of a reduced set of clinical variables. Clinical observations provide the greatest discrimination. Neuropsychological tests are improved by the addition of biomarkers, and both contribute significantly to improve the overall predictive performance.
Full-text · Article · Dec 2015 · Frontiers in Aging Neuroscience
[Show abstract][Hide abstract] ABSTRACT: Patients with major depression who are otherwise medically healthy have activated inflammatory pathways in their organism. It has been described that depression is not only escorted by inflammation but also by induction of multiple oxidative/nitrosative stress pathways. Nevertheless, there are finely regulated mechanisms involved in preserving cells from damage, such as the antioxidant nuclear transcription factor Nrf2. We aim to explore in a depression-like model the Nrf2 pathway in the prefrontal cortex (PFC) and the hippocampus of rats and to analyze whether antidepressants affect the antioxidant activity of the Nrf2 pathway. Male Wistar rats were exposed to chronic mild stress (CMS) and some of them were treated with desipramine, escitalopram or duloxetine. We studied the expression of upstream and downstream elements of the Nrf2 pathway and the oxidative damage induced by the CMS. After CMS, there is an inhibition of upstream and downstream elements of the Nrf2 pathway in the PFC (e.g. PI3K/Akt, GPx...). Moreover, antidepressant treatments, particularly desipramine and duloxetine, are able to recover some of these elements and to reduce the oxidative damage induced by the CMS. However, in the hippocampus, Nrf2 pathways are not that affected and antidepressants do not have many actions. In conclusion, Nrf2 pathway is differentially regulated by antidepressants in the PFC and hippocampus. The Nrf2 pathway is involved in the oxidative/nitrosative damage detected in the PFC and antidepressants have a therapeutic action through this pathway. However, it seems that Nrf2 is not involved in the effects caused by CMS in the hippocampus.
Full-text · Article · Dec 2015 · Neuropharmacology
[Show abstract][Hide abstract] ABSTRACT: Recent studies have suggested that depression is accompanied by an increased intestinal permeability which would be related to the inflammatory pathophysiology of the disease. This study aimed to evaluate whether experimental depression presents with bacterial translocation that in turn can lead to the TLR-4 in the brain affecting the mitogen-activated protein kinases (MAPK) and antioxidant pathways. Male Wistar rats were exposed to chronic mild stress (CMS) and the intestinal integrity, presence of bacteria in tissues and plasma lipopolysaccharide levels were analyzed. We also studied the expression in the prefrontal cortex of activated forms of MAPK and some of their activation controllers and the effects of CMS on the antioxidant Nrf2 pathway. Our results indicate that after exposure to a CMS protocol there is increased intestinal permeability and bacterial translocation. CMS also increases the expression of the activated form of the MAPK p38 while decreasing the expression of the antioxidant transcription factor Nrf2. The actions of antibiotic administration to prevent bacterial translocation on elements of the MAPK and Nrf2 pathways indicate that the translocated bacteria are playing a role in these effects. In effect, our results propose a role of the translocated bacteria in the pathophysiology of depression through the p38 MAPK pathway which could aggravate the neuroinflammation and the oxidative/nitrosative damage present in this pathology. Moreover, our results reveal that the antioxidant factor Nrf2 and its activators may be involved in the consequences of the CMS on the brain.
Full-text · Article · Dec 2015 · Neuropharmacology
[Show abstract][Hide abstract] ABSTRACT: Patients with chronic pain often suffer from affective disorders and cognitive decline, which significantly impairs their quality of life. In addition, many of these patients also experience stress unrelated to their illness, which can aggravate their symptoms. These nociceptive inputs are received by the hippocampus, in which maladaptive neuroplastic changes may occur in the conditions of chronic pain. The hippocampus is a structure involved in emotionality, learning, and memory, and the proliferating cells in the granular layer of the hippocampal dentate gyrus respond to chronic pain by slowing their turnover. However, whether the maturation, survival, and integration of newborn cells in the hippocampus are affected by chronic pain remains unclear. In addition, it is unknown whether an added stress may increase this effect.
We have evaluated the proliferation, differentiation, and survival of newborn hippocampal cells in a rat model of neuropathic pain (chronic constriction injury), with or without stress (chronic immobilization), by assessing the incorporation of bromodeoxyuridine into proliferating cells and immunostaining.
The data obtained indicated that there was a decrease in the number of proliferating cells 8 days after nerve injury in animals subjected to neuropathic pain, an effect that was exacerbated by stress. Moreover, 4 weeks after nerve injury, neuropathic pain was associated with a loss of neuroblasts and the reduced survival of new mature neurons in the hippocampal granular layer, phenomena that also were increased by stress. By contrast, the rate of differentiation was not affected in this paradigm.
Neuropathic pain negatively influences hippocampal neurogenesis (proliferation and survival), and this effect is exacerbated by stress. These neuroplastic changes may account for the affective and cognitive impairment seen in patients with chronic pain.
Full-text · Article · Jul 2015 · Anesthesia and analgesia
[Show abstract][Hide abstract] ABSTRACT: Major depression brings about a heavy socio-economic burden worldwide due to its high prevalence and the low efficacy of antidepressant drugs, mostly inhibiting the serotonin transporter (SERT). As a result, ~80% of patients show recurrent or chronic depression, resulting in a poor quality of life and increased suicide risk. RNA interference (RNAi) strategies have been preliminarily used to evoke antidepressant-like responses in experimental animals. However, the main limitation for the medical use of RNAi is the extreme difficulty to deliver oligonucleotides to selected neurons/systems in the mammalian brain. Here we show that the intranasal administration of a sertraline-conjugated small interfering RNA (C-SERT-siRNA) silenced SERT expression/function and evoked fast antidepressant-like responses in mice. After crossing the permeable olfactory epithelium, the sertraline-conjugated-siRNA was internalized and transported to serotonin cell bodies by deep Rab-7-associated endomembrane vesicles. Seven-day C-SERT-siRNA evoked similar or more marked responses than 28-day fluoxetine treatment. Hence, C-SERT-siRNA (i) downregulated 5-HT1A-autoreceptors and facilitated forebrain serotonin neurotransmission, (ii) accelerated the proliferation of neuronal precursors and (iii) increased hippocampal complexity and plasticity. Further, short-term C-SERT-siRNA reversed depressive-like behaviors in corticosterone-treated mice. The present results show the feasibility of evoking antidepressant-like responses by selectively targeting neuronal populations with appropriate siRNA strategies, opening a way for further translational studies.Molecular Psychiatry advance online publication, 23 June 2015; doi:10.1038/mp.2015.80.
Full-text · Article · Jun 2015 · Molecular Psychiatry
[Show abstract][Hide abstract] ABSTRACT: Meta-analyses confirm that depression is accompanied by signs of inflammation including increased levels of acute phase proteins, e.g., C-reactive protein, and pro-inflammatory cytokines, e.g., interleukin-6. Supporting the translational significance of this, a meta-analysis showed that anti-inflammatory drugs may have antidepressant effects. Here, we argue that inflammation and depression research needs to get onto a new track. Firstly, the choice of inflammatory biomarkers in depression research was often too selective and did not consider the broader pathways. Secondly, although mild inflammatory responses are present in depression, other immune-related pathways cannot be disregarded as new drug targets, e.g., activation of cell-mediated immunity, oxidative and nitrosative stress (O&NS) pathways, autoimmune responses, bacterial translocation, and activation of the toll-like receptor and neuroprogressive pathways. Thirdly, anti-inflammatory treatments are sometimes used without full understanding of their effects on the broader pathways underpinning depression. Since many of the activated immune-inflammatory pathways in depression actually confer protection against an overzealous inflammatory response, targeting these pathways may result in unpredictable and unwanted results. Furthermore, this paper discusses the required improvements in research strategy, i.e., path and drug discovery processes, omics-based techniques, and systems biomedicine methodologies. Firstly, novel methods should be employed to examine the intracellular networks that control and modulate the immune, O&NS and neuroprogressive pathways using omics-based assays, including genomics, transcriptomics, proteomics, metabolomics, epigenomics, immunoproteomics and metagenomics. Secondly, systems biomedicine analyses are essential to unravel the complex interactions between these cellular networks, pathways, and the multifactorial trigger factors and to delineate new drug targets in the cellular networks or pathways. Drug discovery processes should delineate new drugs targeting the intracellular networks and immune-related pathways.
Full-text · Article · May 2015 · Molecular Neurobiology
[Show abstract][Hide abstract] ABSTRACT: BACKGROUND:
The acylethanolamides oleoylethanolamide (OEA) and palmitoylethanolamide (PEA) are endogenous lipid mediators with proposed neuroprotectant properties in CNS pathologies. The precise mechanisms remain partly unknown, but growing evidence suggests an anti-inflammatory/antioxidant profile.
We tested whether OEA/PEA (10 mg/kg, i.p) attenuate neuroinflammation and acute phase responses (HPA stress axis activation, thermoregulation and anhedonia) induced by lipopolysaccharide (LPS, 0.5 mg/kg, i.p.) in rats.
LPS increased mRNA levels of the pro-inflammatory cytokines TNF-α, IL-1β and IL-6, nuclear NF-κB activity and the expression of its inhibitory protein IκBα in cytoplasm, the inducible isoforms of nitric oxide synthase (iNOS) and cyclooxygenase (COX)-2, microsomal prostaglandin E2 synthase (m-PGES-1) mRNA, and pro-inflammatory prostaglandin E2 (PGE2) content in frontal cortex 150 min after administration. As a result, the markers of nitrosative/oxidative stress nitrites (NO2 -) and malondialdehyde (MDA) were increased. Pretreatment with OEA/PEA reduced plasma TNF-α levels after LPS, but only OEA significantly reduced brain TNF-α mRNA. OEA and PEA prevented LPS-induced NF-κB/IκBα up-regulation in nuclear and cytosolic extracts, respectively, the expression of iNOS, COX-2 and m-PGES-1 and the levels of PGE2. Additionally, both acylethanolamides reduced LPS-induced oxidative/nitrosative stress. Neither OEA nor PEA modified plasma corticosterone levels after LPS, but both acylethanolamides reduced the expression of hypothalamic markers of thermoregulation IL-1β, COX-2 and PGE2, and potentiated the hypothermic response after LPS. Interestingly, only OEA disrupted LPS-induced anhedonia in a saccharine preference test.
Results indicate that OEA and PEA have anti-inflammatory/neuroprotective properties and suggest a role for these acylethanolamides as modulators of CNS pathologies with a neuroinflammatory component.
Full-text · Article · Dec 2014 · The International Journal of Neuropsychopharmacology
[Show abstract][Hide abstract] ABSTRACT: Neurodevelopmental disruptions caused by obstetric complications play a role in the etiology of several phenotypes associated with neuropsychiatric diseases and cognitive dysfunctions. Importantly, it has been noticed that epigenetic processes occurring early in life may mediate these associations. Here, DNA methylation signatures at IGF2 (insulin-like growth factor 2) and IGF2BP1-3 (IGF2-binding proteins 1-3) were examined in a sample consisting of 34 adult monozygotic (MZ) twins informative for obstetric complications and cognitive performance. Multivariate linear regression analysis of twin data was implemented to test for associations between methylation levels and both birth weight (BW) and adult working memory (WM) performance. Familial and unique environmental factors underlying these potential relationships were evaluated. A link was detected between DNA methylation levels of two CpG sites in the IGF2BP1 gene and both BW and adult WM performance. The BW-IGF2BP1 methylation association seemed due to non-shared environmental factors influencing BW, whereas the WM-IGF2BP1 methylation relationship seemed mediated by both genes and environment. Our data is in agreement with previous evidence indicating that DNA methylation status may be related to prenatal stress and later neurocognitive phenotypes. While former reports independently detected associations between DNA methylation and either BW or WM, current results suggest that these relationships are not confounded by each other.
[Show abstract][Hide abstract] ABSTRACT: The objective of the study is to examine the association of baseline total antioxidant status (TAS) and glutathione (GSH) levels with short- and long-term cognitive functioning in patients with early onset first-episode psychosis, comparing affective and non-affective psychoses.
We analysed 105 patients with an early onset-first episode psychosis (age 9–17 years) and 97 healthy controls. Blood samples were taken at admission for measurement of TAS and GSH, and cognitive performance was assessed at baseline and at 2 years of follow-up. Regression analysis was used to assess the relationship between TAS/GSH levels at baseline and cognitive performance at both time points, controlling for confounders.
Baseline TAS and GSH levels were significantly lower in patients than healthy controls. In patients, baseline TAS was positively associated with the global cognition score at baseline (p = 0.048) and two years later (p = 0.005), while TAS was not associated with cognitive functioning in healthy controls. Further, baseline TAS in patients was specifically associated with the memory domain at baseline and with the memory and attention domains two years later. Stratifying by affective and non-affective psychoses, significant associations were only found between TAS and cognition in the non-affective psychosis group. Baseline GSH levels were not associated with cognitive functioning at either time point in either group.
The antioxidant defence capacity in early onset first-episode psychotic patients is directly correlated with global cognition at baseline and at 2 years of follow-up, especially in non-affective psychosis.
Full-text · Article · Jun 2014 · Schizophrenia Research
[Show abstract][Hide abstract] ABSTRACT: Stress-exposure produces excitoxicity and neuroinflammation, contributing to the cellular damage observed in stress-related neuropathologies. The endocannabinoid system is present in stress-responsive neural circuits and it is emerging as a homeostatic system. The aim of this study was to elucidate the possible regulatory role of cannabinoid-2 receptor in stress-induced excitotoxicity and neuroinflammation.
Different genetic and pharmacological approaches were used: 1) Wild type (WT), transgenic over-expressing CB2 receptor (CB2xP) and CB2 receptor knockout (CB2-KO) mice were exposed to immobilization/acoustic stress (2h/day for 4 days), and 2) the CB2 receptor agonist JWH-133 was administered daily (2 mg kg(-1) , i.p.) to WT and CB2 receptor-KO animals.
Stress-induced HPA axis activation was not modified by CB2 receptor manipulations. JWH-133 treatment or overexpression of CB2 resulted in an increase of control levels of glutamate uptake, which is then reduced by stress exposure back to control levels. JWH-133 prevented the stress-induced increase in the cytokines TNF-α and MCP-1, the nuclear factor kappa B, the enzymes inducible nitric oxide synthase 2 and cyclooxygenase-2 and the cellular oxidative/nitrosative damage (lipid peroxidation) in brain frontal cortex. CB2xP mice displayed anti-inflammatory/neuroprotective actions similar to those observed in JWH-133 pre-treated animals. Conversely, CB2-KO mice experiments indicated that the lack of CB2 receptor exacerbated stress-induced neuroinflammatory responses and validated the CB2 receptor-dependent effects of JWH-133.
These results suggest that pharmacological manipulation of CB2 receptor is a potential therapeutic strategy for the treatment of stress-related pathologies with a neuroinflammatory component, such as depression.
Full-text · Article · Jan 2014 · British Journal of Pharmacology
[Show abstract][Hide abstract] ABSTRACT: The innate immune response is the first line of defence against invading microorganisms and it is also activated in different neurologic/neurodegenerative pathological scenarios. As a result, the family of the innate immune toll-like receptors (TLRs) and, in particular, the genetic/pharmacological manipulation of the TLR-4 signalling pathway emerges as a potential therapeutic strategy. Growing evidence relates stress exposure with altered immune responses, but the precise role of TLR-4 remains partly unknown.
The present study aimed to elucidate whether the elements of the TLR-4 signalling pathway are activated after acute stress exposure in rat brain frontal cortex and its role in the regulation of the stress-induced neuroinflammatory response, by means of its pharmacological modulation with the intravenous administration of the TLR-4 specific inhibitor TAK-242. Considering that TLR-4 responds predominantly to lipopolysaccharide from gram-negative bacteria, we checked whether increased intestinal permeability and a resultant bacterial translocation is a potential regulatory mechanism of stress-induced TLR-4 activation.
Acute restraint stress exposure upregulates TLR-4 expression both at the mRNA and protein level. Stress-induced TLR-4 upregulation is prevented by the protocol of antibiotic intestinal decontamination made to reduce indigenous gastrointestinal microflora, suggesting a role for bacterial translocation on TLR-4 signalling pathway activation. TAK-242 pre-stress administration prevents the accumulation of potentially deleterious inflammatory and oxidative/nitrosative mediators in the brain frontal cortex of rats.
The use of TAK-242 or other TLR-4 signalling pathway inhibitory compounds could be considered as a potential therapeutic adjuvant strategy to constrain the inflammatory process taking place after stress exposure and in stress-related neuropsychiatric diseases.
Full-text · Article · Jan 2014 · Journal of Neuroinflammation