Chronic antidepressant treatments resulted in altered expression of genes involved in inflammation in the rat hypothalamus

Effects of selective serotonin reuptake inhibitors on endocrine system (Review)

Selective serotonin reuptake inhibitors (SSRIs) are typically prescribed for treating major depressive disorder (MDD) due to their high efficacy. These drugs function by inhibiting the reuptake of serotonin [also termed 5-hydroxytryptamine (5-HT)], which raises the levels of 5-HT in the synaptic cleft, leading to prolonged activation of postsynaptic 5-HT receptors. Despite the therapeutic benefits of SSRIs, this mechanism of action also disturbs the neuroendocrine response. Hypothalamic-pituitary-adrenal (HPA) axis activity is strongly linked to both MDD and the response to antidepressants, owing to the intricate interplay within the serotonergic system, which regulates feeding, water intake, sexual drive, reproduction and circadian rhythms. The aim of the present review was to provide up-to-date evidence for the proposed effects of SSRIs, such as fluoxetine, citalopram, escitalopram, paroxetine, sertraline and fluvoxamine, on the endocrine system. For this purpose, the literature related to the effects of SSRIs on the endocrine system was searched using the PubMed database. According to the available literature, SSRIs may have an adverse effect on glucose metabolism, sexual function and fertility by dysregulating the function of the HPA axis, pancreas and gonads. Therefore, considering that SSRIs are often prescribed for extended periods, it is crucial to monitor the patient closely with particular attention to the function of the endocrine system.

Sleep promoting and omics exploration on probiotics fermented Gastrodia elata Blume

Fermenting Chinese medicinal herbs could enhance their bioactivities. We hypothesized probiotic-fermented gastrodia elata Blume (GE) with better potential to alleviate insomnia than that of unfermented, thus the changes in chemical composition and the insomnia-alleviating effects and mechanisms of fermented GE on pentylenetetrazole (PTZ)-induced insomnia zebrafish were explored via high-performance liquid chromatography (HPLC) and mass spectroscopy-coupled HPLC (HPLC-MS), phenotypic, transcriptomic, and metabolomics analysis. The results demonstrated that probiotic fermented GE performed better than unfermented GE in increasing the content of chemical composition, reducing the displacement, average speed, and number of apoptotic cells in zebrafish with insomnia. Metabolomic investigation showed that the anti-insomnia effect was related to regulating the pathways of actin cytoskeleton and neuroactive ligand-receptor interactions. Transcriptomic and reverse transcription qPCR (RT-qPCR) analysis revealed that secondary fermentation liquid (SFL) significantly modulated the expression levels of neurod1, msh2, msh3, recql4, ercc5, rad5lc, and rev3l, which are mainly involved in neuron differentiation and DNA repair. Collectively, as a functional food, fermented GE possessed potential for insomnia alleviation.

Interleukin‑18 binding protein: Biological properties and roles in human and animal immune regulation (Review)

IL-18 binding protein (IL-18BP) is a natural regulatory molecule of the proinflammatory cytokine IL-18. It can regulate activity of IL-18 by high affinity binding. The present review aimed to highlight developments, characteristics and functions of IL-18BP. IL-18BP serves biological and anti-pathological roles in treating disease. In humans, it modulates progression of a number of chronic diseases, such as adult-onset Still's disease. The present review summarizes molecular structure, role of IL-18BP in disease and interaction with other proteins in important pathological processes.

Common changes in rat cortical gene expression after antidepressant drug treatment: Impacts on metabolism of polyamines, mRNA splicing, regulation of RAS by GAPs, neddylation and GPCR ligand binding

OBJECTIVES

This study sought to identify pathways affected by rat cortical RNA that were changed after treatment with fluoxetine or imipramine.

METHODS

We measured levels of cortical RNA in male rats using GeneChip® Rat Exon 1.0 ST Array after treatment with vehicle (0.9% NaCl), fluoxetine (10 mg/kg/day) or imipramine (20 mg/kg/day) for 28 days. Levels of coding and non-coding RNA in vehicle treated rats were compared to those in treated rats using ANOVA in JMP Genomics 13 and the Panther Gene Ontology Classification System was used to identify pathways involving the changed RNAs.

RESULTS

18,876 transcripts were detected; there were highly correlated changes in 1010 levels of RNA after both drug treatments that would principally affect the metabolism of polyamines, mRNA splicing, regulation of RAS by GAPs, neddylation and GPCR ligand binding. Using our previously published data, we compared changes in transcripts after treatment with antipsychotic and mood stabilising drugs.

CONCLUSIONS

Our study shows there are common, correlated, changes in coding and non-coding RNA in the rat cortex after treatment with fluoxetine or imipramine; we propose the pathways affected by these changes are involved in the therapeutic mechanisms of action of antidepressant drugs.

Anti-insomnia Effect of a Polyherbal Formulation on P-chlorophenyalanine Induced Experimental Animal Model

Sleep is a dynamic and controlled set of physiological and behavioural practices during which the stabilisation and restoration processes of the body take place properly. Therefore, sleep disorders, especially chronic insomnia, can harm an individual's physical and mental health. However, the therapeutic alternatives are limited and possess severe side effects. Thus, in this study, we aimed to investigate the anti-insomnia effect of a polyherbal formulation (Sleep) (SLP) on p-chlorophenyalanine (PCPA) induced insomnia in rats. Intraperitoneal injection of PCPA induced the experimental condition, and the therapeutic effect of SLP was evaluated by studying the sleep pattern and expression of various neurotransmitters and receptors, along with neurotrophins. Moreover, insomnia-associated oxidative stress and inflammation were also studied. From the findings, we found that the SLP-supplemented animals improved their sleeping behaviour and that the major neurotransmitters, hormones, and receptors were maintained at an equilibrium level. Furthermore, the neurotrophin level was increased and pro-inflammatory cytokines were reduced. The evaluation of oxidative stress markers shows that the antioxidants were significantly boosted, and as a result, lipid peroxidation was prevented. The overall findings suggest that SLP can be used as an effective medication for the treatment of sleep disorders like insomnia as it triggers the major neurotransmitter system.

Towards Novel Potential Molecular Targets for Antidepressant and Antipsychotic Pharmacotherapies

Depression and schizophrenia are two highly prevalent and severely debilitating neuropsychiatric disorders. Both conventional antidepressant and antipsychotic pharmacotherapies are often inefficient clinically, causing multiple side effects and serious patient compliance problems. Collectively, this calls for the development of novel drug targets for treating depressed and schizophrenic patients. Here, we discuss recent translational advances, research tools and approaches, aiming to facilitate innovative drug discovery in this field. Providing a comprehensive overview of current antidepressants and antipsychotic drugs, we also outline potential novel molecular targets for treating depression and schizophrenia. We also critically evaluate multiple translational challenges and summarize various open questions, in order to foster further integrative cross-discipline research into antidepressant and antipsychotic drug development.

Molecular Basic of Pharmacotherapy of Cytokine Imbalance as a Component of Intervertebral Disc Degeneration Treatment

Intervertebral disc degeneration (IDD) and associated conditions are an important problem in modern medicine. The onset of IDD may be in childhood and adolescence in patients with a genetic predisposition. With age, IDD progresses, leading to spondylosis, spondylarthrosis, herniated disc, spinal canal stenosis. One of the leading mechanisms in the development of IDD and chronic back pain is an imbalance between pro-inflammatory and anti-inflammatory cytokines. However, classical therapeutic strategies for correcting cytokine imbalance in IDD do not give the expected response in more than half of the cases. The purpose of this review is to update knowledge about new and promising therapeutic strategies based on the correction of the molecular mechanisms of cytokine imbalance in patients with IDD. This review demonstrates that knowledge of the molecular mechanisms of the imbalance between pro-inflammatory and anti-inflammatory cytokines may be a new key to finding more effective drugs for the treatment of IDD in the setting of acute and chronic inflammation.

An integrated cytokine and kynurenine network as the basis of neuroimmune communication

Two of the molecular families closely associated with mediating communication between the brain and immune system are cytokines and the kynurenine metabolites of tryptophan. Both groups regulate neuron and glial activity in the central nervous system (CNS) and leukocyte function in the immune system, although neither group alone completely explains neuroimmune function, disease occurrence or severity. This essay suggests that the two families perform complementary functions generating an integrated network. The kynurenine pathway determines overall neuronal excitability and plasticity by modulating glutamate receptors and GPR35 activity across the CNS, and regulates general features of immune cell status, surveillance and tolerance which often involves the Aryl Hydrocarbon Receptor (AHR). Equally, cytokines and chemokines define and regulate specific populations of neurons, glia or immune system leukocytes, generating more specific responses within restricted CNS regions or leukocyte populations. In addition, as there is a much larger variety of these compounds, their homing properties enable the superimposition of dynamic variations of cell activity upon local, spatially limited, cell populations. This would in principle allow the targeting of potential treatments to restricted regions of the CNS. The proposed synergistic interface of 'tonic' kynurenine pathway affecting baseline activity and the superimposed 'phasic' cytokine system would constitute an integrated network explaining some features of neuroimmune communication. The concept would broaden the scope for the development of new treatments for disorders involving both the CNS and immune systems, with safer and more effective agents targeted to specific CNS regions.

Fluoxetine improves bone microarchitecture and mechanical properties in rodents undergoing chronic mild stress - an animal model of depression

Depression is one of the most prevalent mental disorders associated with reductions in bone mineral density and increased fracture risk. Fluoxetine is a highly prescribed selective serotonin reuptake inhibitor (SSRI) in the treatment of depression and is reported to be a risk factor for fractures. The present study examined the effect of fluoxetine on bone microarchitecture and the mechanical properties under chronic mild stress (CMS), a rodent model of depression. Thirty-one 6-9 week-old rats were allocated to 4 groups: 1) CMS + fluoxetine group (n = 10), 2) fluoxetine-only group (n = 5), 3) CMS + placebo group (n = 10) and 4) control group (no CMS and treatment) (n = 6). After 16 weeks, bone microarchitecture of the distal femur was analyzed by µCT. Mechanical properties were assessed by the three-point bending test, and antidepressant efficacy was determined by sucrose preference and forced swimming tests. Significant correlations were found between volume of sucrose intake and bone volume/tissue volume (BV/TV) (p = 0.019) and elastic absorption energy (p = 0.001) in the fluoxetine only group. The fluoxetine-only group showed significantly higher in the second moment of area in y-direction (p = 0.0298), horizontal outer diameter (mm) (p = 0.0488) and average midshaft thickness (mm) (p = 0.00047) than control group. Comparing with the control group, there was a significant reduction in trabecular number (Tb.N) in the CMS + fluoxetine group (p = 0.026) but not the fluoxetine-only group (p > 0.05). Significant increases in trabecular separation were observed in the metaphysis of CMS + placebo (p = 0.003) and CMS + fluoxetine (p = 0.004) groups when compared to the control group but not in the fluoxetine-only group (p > 0.05). During the three-point bending test, the fluoxetine-only group demonstrated significantly higher structural strength than controls (p = 0.04). Micro computed tomography (µCT) slices showed loss of trabecular bone in the metaphysis region of the CMS + fluoxetine and CMS + placebo groups but not the fluoxetine-only and control groups. In an animal model of depression, the adverse effect on the bone microarchitecture was caused by CMS but not by fluoxetine. Without exposure to CMS, fluoxetine significantly increased the cross-sectional area, trabecular bone area, structural strength and osteoblasts / bone area as compared to control condition.

Valerian essential oil for treating insomnia via the serotonergic synapse pathway

Valerian volatile oil can be used in the treatment of insomnia; however, the active components and mechanisms of action are currently unclear. Therefore, we used transcriptome sequencing and weight coefficient network pharmacology to predict the effective components and mechanism of action of valerian volatile oil in an insomnia model induced by intraperitoneal injection of para-Chlorophenylalanine (PCPA) in SD rats. Valerian essential oil was given orally for treatment and the contents of 5-hydroxytryptamine receptor 1 A (5-HT1AR), γ-aminobutyric acid (GABA), cyclic adenosine monophosphate (cAMP), and protein kinase A (PKA) in the hippocampus of rats in each group were detected by enzyme-linked immunosorbent assay (ELISA), western blot, Polymerase Chain Reaction (PCR), and immunohistochemistry. The results showed that after treatment with valerian essential oil, insomnia rats showed significantly prolonged sleep duration and alleviated insomnia-induced tension and anxiety. Regarding the mechanism of action, we believe that caryophyllene in valerian essential oil upregulates the 5-HT1AR receptor to improve the activity or affinity of the central transmitter 5-HT, increase the release of 5-HT, couple 5-HT with a G protein coupled receptor, convert adenosine triphosphate (ATP) into cAMP (catalyzed by ADCY5), and then directly regulate the downstream pathway. Following pathway activation, we propose that the core gene protein kinase PKA activates the serotonergic synapse signal pathway to increase the expression of 5-HT and GABA, thus improving insomnia symptoms and alleviating anxiety. This study provides a theoretical basis for the application of valerian volatile oil in health food.

Combinatorial Regimen of Carbamazepine and Imipramine Exhibits Synergism against Grandmal Epilepsy in Rats: Inhibition of Pro-Inflammatory Cytokines and PI3K/Akt/mTOR Signaling Pathway

Epilepsy is a neurodegenerative disorder that causes recurring seizures. Thirty-five percent of patients remain refractory, with a higher prevalence of depression. We investigated the anticonvulsant efficacy of carbamazepine (CBZ; 20 and 50 mg/kg), imipramine (IMI; 10 and 20 mg/kg) alone, and as a low dose combination. This preclinical investigation included dosing of rats for 14 days followed by elicitation of electroshock on the last day of treatment. Along with behavioral monitoring, the rat hippocampus was processed for quantification of mTOR, IL-1β, IL-6 and TNF-α levels. The histopathological analysis of rat hippocampus was performed to ascertain neuroprotection. In vitro studies and in silico studies were also conducted. We found that the low dose combinatorial therapy of CBZ (20 mg/kg) + IMI (10 mg/kg) exhibits synergism (p < 0.001) in abrogation of maximal electroshock (MES) induced convulsions/tonic hind limb extension (THLE), by reducing levels of pro-inflammatory cytokines, and weakening of the PI3K/Akt/mTOR signal. The combination also exhibits cooperative binding at the Akt. As far as neuroprotection is concerned, the said combination increased cell viability by 166.37% compared to Pentylenetetrazol (PTZ) treated HEK-293 cells. Thus, the combination of CBZ (20 mg/kg) + IMI (10 mg/kg) is a fruitful combination therapy to elevate seizure threshold and provide neuroprotection.

Vortioxetine Prevents Lipopolysaccharide-Induced Memory Impairment Without Inhibiting the Initial Inflammatory Cascade

Vortioxetine is a novel multimodal antidepressant that modulates a wide range of neurotransmitters throughout the brain. Preclinical and clinical studies have shown that vortioxetine exerts positive effects on different cognitive domains and neuroprotective effects. Considering the key role of microglial cells in brain plasticity and cognition, we aimed at investigating the effects of pretreatment with vortioxetine in modulating behavioral and molecular effects induced by an immune challenge: peripheral injection of lipopolysaccharide (LPS). To this purpose, C57BL/6J male mice were first exposed to a 28-day standard diet or vortioxetine-enriched diet, which was followed by an acute immune challenge with LPS. Sickness symptoms and depressive-like behaviors (anhedonia and memory impairment) were tested 6 and 24 h after exposure to LPS, respectively. Moreover, the expressions of markers of immune activation and M1/M2 markers of microglia polarization were measured in the dorsal and ventral parts of the hippocampus. The pretreatment with vortioxetine did not affect both LPS-induced sickness behavior and anhedonia but prevented the deficit in the recognition memory induced by the immune challenge. At the transcriptional level, chronic exposure to vortioxetine did not prevent LPS-induced upregulation of proinflammatory cytokines 6 h after the immune challenge but rather seemed to potentiate the immune response to the challenge also by affecting the levels of expression of markers of microglia M1 phenotype, like cluster of differentiation (CD)14 and CD86, in an area-dependent manner. However, at the same time point, LPS injection significantly increased the expression of the M2 polarization inducer, interleukin 4, only in the hippocampus of animals chronically exposed to vortioxetine. These results demonstrate that a chronic administration of vortioxetine specifically prevents LPS-induced memory impairment, without affecting acute sickness behavior and anhedonia, and suggest that hippocampal microglia may represent a cellular target of this novel antidepressant medication. Moreover, we provide a useful model to further explore the molecular mechanisms specifically underlying cognitive impairments following an immune challenge.

Advances in novel molecular targets for antidepressants

Depression is the most common psychiatric illness affecting numerous people world-wide. The currently available antidepressant treatment presents low response and remission rates. Thus, new effective antidepressants need to be developed or discovered. Aiming to give an overview of novel possible antidepressant drug targets, we summarized the molecular targets of antidepressants and the underlying neurobiology of depression. We have also addressed the multidimensional perspectives on the progress in the psychopharmacological treatment of depression and on the new potential approaches with effective drug discovery.

Rps27a might act as a controller of microglia activation in triggering neurodegenerative diseases

Neurodegenerative diseases (NDDs) are increasing serious menaces to human health in the recent years. Despite exhibiting different clinical phenotypes and selective neuronal loss, there are certain common features in these disorders, suggesting the presence of commonly dysregulated pathways. Identifying causal genes and dysregulated pathways can be helpful in providing effective treatment in these diseases. Interestingly, in spite of the considerable researches on NDDs, to the best of our knowledge, no dysregulated genes and/or pathways were reported in common across all the major NDDs so far. In this study, for the first time, we have applied the three-way interaction model, as an approach to unravel sophisticated gene interactions, to trace switch genes and significant pathways that are involved in six major NDDs. Subsequently, a gene regulatory network was constructed to investigate the regulatory communication of statistically significant triplets. Finally, KEGG pathway enrichment analysis was applied to find possible common pathways. Because of the central role of neuroinflammation and immune system responses in both pathogenic and protective mechanisms in the NDDs, we focused on immune genes in this study. Our results suggest that "cytokine-cytokine receptor interaction" pathway is enriched in all of the studied NDDs, while "osteoclast differentiation" and "natural killer cell mediated cytotoxicity" pathways are enriched in five of the NDDs each. The results of this study indicate that three pathways that include "osteoclast differentiation", "natural killer cell mediated cytotoxicity" and "cytokine-cytokine receptor interaction" are common in five, five and six NDDs, respectively. Additionally, our analysis showed that Rps27a as a switch gene, together with the gene pair {Il-18, Cx3cl1} form a statistically significant and biologically relevant triplet in the major NDDs. More specifically, we suggested that Cx3cl1 might act as a potential upstream regulator of Il-18 in microglia activation, and in turn, might be controlled with Rps27a in triggering NDDs.

Systemic immunization with altered myelin basic protein peptide produces sustained antidepressant-like effects

Immune dysregulation, specifically of inflammatory processes, has been linked to behavioral symptoms of depression in both human and rodent studies. Here, we evaluated the antidepressant effects of immunization with altered peptide ligands of myelin basic protein (MBP)-MBP_87-99[A⁹¹, A⁹⁶], MBP_87-99[A⁹¹], and MBP_87-99[R⁹¹, A⁹⁶]-in different models of depression and examined the mechanism by which these peptides protect against stress-induced depression. We found that a single dose of subcutaneously administered MBP_87-99[A⁹¹, A⁹⁶] produced antidepressant-like effects by decreasing immobility in the forced swim test and by reducing the escape latency and escape failures in the learned helplessness paradigm. Moreover, immunization with MBP_87-99[A⁹¹, A⁹⁶] prevented and reversed depressive-like and anxiety-like behaviors that were induced by chronic unpredictable stress (CUS). However, MBP_87-99[R⁹¹, A⁹⁶] tended to aggravate CUS-induced anxiety-like behavior. Chronic stress increased the production of peripheral and central proinflammatory cytokines and induced the activation of microglia in the prelimbic cortex (PrL), which was blocked by MBP_87-99[A⁹¹, A⁹⁶]. Immunization with MBP-derived altered peptide ligands also rescued chronic stress-induced deficits in p11, phosphorylated cyclic adenosine monophosphate response element binding protein, and brain-derived neurotrophic factor expression. Moreover, microinjections of recombinant proinflammatory cytokines and the knockdown of p11 in the PrL blunted the antidepressant-like behavioral response to MBP_87-99[A⁹¹, A⁹⁶]. Altogether, these findings indicate that immunization with altered MBP peptide produces prolonged antidepressant-like effects in rats, and the behavioral response is mediated by inflammatory factors (particularly interleukin-6), and p11 signaling in the PrL. Immune-neural interactions may impact central nervous system function and alter an individual's response to stress.

Major depressive disorders accompanying autoimmune diseases - Response to treatment

MDDs (major depressive disorders) belong to the most frequently diagnosed mental diseases and affect approximately 350 million people all over the world. A growing body of evidence suggests that inflammatory processes may play a significant role in the pathophysiology and progression of the disease. The comorbidity of MDDs with many other medical conditions, for example autoimmune diseases (ADs) caused by inflammation, has been observed on numerous occasions. In both cases, increased levels of pro-inflammatory cytokines, chemokines and other inflammatory agents are observed. Furthermore, higher rates of inflammatory markers are associated with a poorer response to antidepressant treatment. Additionally, the presence of any AD is associated with higher prevalence of depression and may reduce the chance of effective therapy. Interestingly, the administration of several anti-inflammatory agents used in AD treatment is positively correlated with a reduction of depressive symptoms. In conclusion, the factors contributing to the coexistence of depression as well as affecting antidepressant treatment effectiveness may lead to an alteration of the cytokine profiles in many autoimmune diseases.

Piperlongumine produces antidepressant-like effects in rats exposed to chronic unpredictable stress

Piperlongumine, an alkaloid compound extracted from Peper longum L, has been reported to produce neuroprotective effects in the brain and exert various pharmacological activities such as antitumor, antiangiogenic, anti-inflammatory and analgesic properties. The aim of this study was to investigate the antidepressant-like effects and the possible mechanism of action of piperlongumine in a chronic unpredictable stress (CUS) model. We found that, with venlafaxine as a positive control, orally administered piperlongumine (12.5 and 25 mg/kg) for 7 days, not a single dose, significantly reduced immobility time in the forced swimming test, but did not alter locomotor activity in the open field test, indicating that piperlongumine has antidepressant-like effects without nonspecific motor changes. Then, using the CUS model of depression, piperlongumine was administrated orally for 4 weeks, followed by sucrose preference and forced swimming tests to evaluate the depressive-like behaviors. We found that piperlongumine reversed both the decreased sucrose preference and increased immobility time in rats exposed to CUS. In addition, piperlongumine also reversed the increase in proinflammatory cytokine levels in the hippocampus of rats in the CUS model. Altogether, the present study demonstrated that piperlongumine exhibits the antidepressant-like effects in rats, which may be mediated by the inhibition of the neuronal inflammation in the hippocampus.

Interplay between inflammation and neural plasticity: Both immune activation and suppression impair LTP and BDNF expression

An increasing number of studies show that both inflammation and neural plasticity act as key players in the vulnerability and recovery from psychiatric disorders and neurodegenerative diseases. However, the interplay between these two players has been limitedly explored. In fact, while a few studies reported an immune activation, others conveyed an immune suppression, associated with an impairment in neural plasticity. Therefore, we hypothesized that deviations in inflammatory levels in both directions may impair neural plasticity. We tested this hypothesis experimentally, by acute treatment of C57BL/6 adult male mice with different doses of two inflammatory modulators: lipopolysaccharide (LPS), an endotoxin, and ibuprofen (IBU), a nonselective cyclooxygenase inhibitor, which are respectively a pro- and an anti-inflammatory agent. The results showed that LPS and IBU have different effects on behavior and inflammatory response. LPS treatment induced a reduction of body temperature, a decrease of body weight and a reduced food and liquid intake. In addition, it led to increased levels of inflammatory markers expression, both in the total hippocampus and in isolated microglia cells, including Interleukin (IL)-1β, and enhanced the concentration of prostaglandin E₂ (PGE₂). On the other hand, IBU increased the level of anti-inflammatory markers, decreased tryptophan 2,3-dioxygenase (TDO2), the first step in the kynurenine pathway known to be activated during inflammatory conditions, and PGE₂ levels. Though LPS and IBU administration differently affected mediators related with pro- or anti-inflammatory responses, they produced overlapping effects on neural plasticity. Indeed, higher doses of both LPS and IBU induced a statistically significant decrease in the amplitude of long-term potentiation (LTP), in Brain-Derived Neurotrophic Factor (BDNF) expression levels and in the phosphorylation of the AMPA (α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid) receptor subunit GluR1, compared to the control group. Such effect appears to be dose-dependent since only the higher, but not the lower, dose of both compounds led to a plasticity impairment. Overall, the present findings indicate that acute treatment with pro- and anti-inflammatory agents impair neural plasticity in a dose dependent manner.

Increased Serum Levels of Cortisol and Inflammatory Cytokines in People With Depression

This cross-sectional study aimed at measuring the correlation and association between serum levels of cortisol, inflammatory cytokines, and depression and to measure the detection accuracy of serum levels of cortisol in serum samples. In total, 89 male participants were recruited into this study from June 15, 2017, to September 31, 2017. The Hamilton Depression Rating Scale, Beck Anxiety Inventory, and Pittsburgh Sleep Quality Index were used to investigate the mental health status of the participants. Serum concentrations of cortisol and inflammatory cytokines were determined. The serum cortisol concentration, anxiety level, and sleep quality were included in the final logistic regression model. Serum cortisol was able to accurately distinguish between patients with depression and those without depression. There was a significant positive correlation between serum cortisol levels and Hamilton Depression Rating Scale scores.

Modulation of neuroplasticity-related targets following stress-induced acute escape deficit

Understanding resilience is a major challenge to improve current pharmacological therapies aimed at complementing psychological-based approaches of stress-related disorders. In particular, resilience is a multi-factorial construct where the complex network of molecular events that drive the process still needs to be resolved. Here, we exploit the acute escape deficit model, an animal model based on exposure to acute unavoidable stress followed by an escape test, to define vulnerable and resilient phenotypes in rats. Hippocampus and prefrontal cortex (PFC), two of the brain areas most involved in the stress response, were analysed for gene expression at two different time points (3 and 24 h) after the escape test. Total Brain-Derived Neurotrophic Factor (BDNF) was highly responsive in the PFC at 24-h after the escape test, while expression of BDNF transcript IV increased in the hippocampus of resistant animals 3 h post-test. Expression of memory enhancers like Neuronal PAS Domain Protein 4 (Npas4) and Activity-regulated cytoskeleton-associated protein (Arc) decreased in a time- and region-dependent fashion in both behavioural phenotypes. Also, the memory inhibitor Protein Phosphatase 1 (Ppp1ca) was increased in the hippocampus of resilient rats at 3 h post-test. Given the importance of neurotrophic factors and synaptic plasticity-related genes for the development of appropriate coping strategies, our data contribute to an additional step forward in the comprehension of the psychobiology of stress and resiliency.

Combined Fluoxetine and Metformin Treatment Potentiates Antidepressant Efficacy Increasing IGF2 Expression in the Dorsal Hippocampus

An increasing number of studies show that selective serotonin reuptake inhibitors (SSRIs) exert their therapeutic action, at least in part, by amplifying the influence of the living environment on mood. As a consequence, when administered in a favorable environment, SSRIs lead to a reduction of symptoms, but in stressful conditions, they show limited efficacy. Therefore, novel therapeutic approaches able to neutralize the influence of the stressful environment on treatment are needed. The aim of our study was to test whether, in a mouse model of depression, the combined administration of SSRI fluoxetine and metformin, a drug able to improve the metabolic profile, counteracts the limited efficacy of fluoxetine alone when administered in stressful conditions. Indeed, metabolic alterations are associated to both the onset of major depression and the antidepressant efficacy. To this goal, adult C57BL/6 male mice were exposed to stress for 6 weeks; the first two weeks was aimed at generating a mouse model of depression. During the remaining 4 weeks, mice received one of the following treatments: vehicle, fluoxetine, metformin, or a combination of fluoxetine and metformin. We measured liking- and wanting-type anhedonia as behavioral phenotypes of depression and assessed the expression levels of selected genes involved in major depressive disorder and antidepressant response in the dorsal and ventral hippocampus, which are differently involved in the depressive symptomatology. The combined treatment was more effective than fluoxetine alone in ameliorating the depressive phenotype after one week of treatment. This was associated to an increase in IGF2 mRNA expression and enhanced long-term potentiation, specifically in the dorsal hippocampus, at the end of treatment. Overall, the present results show that, when administered in stressful conditions, the combined fluoxetine and metformin treatment may represent a more effective approach than fluoxetine alone in a short term. Finally, our findings highlight the relevance of polypharmacological strategy as effective interventions to increase the efficacy of the antidepressant drugs currently available.

LPS-induced histone H3 phospho(Ser10)-acetylation(Lys14) regulates neuronal and microglial neuroinflammatory response

Epigenetic modifications of DNA and histone proteins are emerging as fundamental mechanisms by which neural cells adapt their transcriptional response to environmental cues, such as, immune stimuli or stress. In particular, histone H3 phospho(Ser10)-acetylation(Lys14) (H3S10phK14ac) has been linked to activation of specific gene expression. The purpose of this study was to investigate the role of H3S10phK14ac in a neuroinflammatory condition. Adult male rats received a intraperitoneal injection of lipopolysaccharide (LPS) (830 μg/Kg/i.p., n = 6) or vehicle (saline 1 mL/kg/i.p., n = 6) and were sacrificed 2 or 6 h later. We showed marked region- and time-specific increases in H3S10phK14ac in the hypothalamus and hippocampus, two principal target regions of LPS. These changes were accompanied by a marked transcriptional activation of interleukin (IL) 1β, IL-6, Tumour Necrosis Factor (TNF) α, the inducible nitric oxide synthase (iNOS) and the immediate early gene c-Fos. By means of chromatin immunoprecipitation, we demonstrated an increased region- and time-specific association of H3S10phK14ac with the promoters of IL-6, c-Fos and iNOS genes, suggesting that part of the LPS-induced transcriptional activation of these genes is regulated by H3S10phK14ac. Finally, by means of multiple immunofluorescence approach, we showed that increased H3S10phK14ac is cell type-specific, being neurons and reactive microglia, the principal histological types involved in this response. Present data point to H3S10phK14ac as a principal epigenetic regulator of neural cell response to systemic LPS and underline the importance of distinct time-, region- and cell-specific epigenetic mechanisms that regulate gene transcription to understand the mechanistic complexity of neuroinflammatory response to immune challenges.

Ammoxetine attenuates diabetic neuropathic pain through inhibiting microglial activation and neuroinflammation in the spinal cord

Background

Diabetic neuropathic pain (DNP) is a common and distressing complication in patients with diabetes, and the underlying mechanism remains unclear. Tricyclic antidepressants (TCAs) and serotonin and norepinephrine reuptake inhibitors (SNRIs) are recommended as first-line drugs for DNP. Ammoxetine is a novel and potent SNRI that exhibited a strong analgesic effect on models of neuropathic pain, fibromyalgia-related pain, and inflammatory pain in our primary study. The present study was undertaken to investigate the chronic treatment properties of ammoxetine on DNP and the underlying mechanisms for its effects.

Methods

The rat model of DNP was established by a single streptozocin (STZ) injection (60 mg/kg). Two weeks after STZ injection, the DNP rats were treated with ammoxetine (2.5, 5, and 10 mg/kg/day) for 4 weeks. The mechanical allodynia and locomotor activity were assayed to evaluate the therapeutic effect of ammoxetine. In mechanism study, the activation of microglia, astrocytes, the protein levels of pro-inflammatory cytokines, the mitogen-activated protein kinases (MAPK), and NF-κB were evaluated. Also, microglia culture was used to assess the direct effects of ammoxetine on microglial activation and the signal transduction mechanism.

Results

Treatment with ammoxetine for 4 weeks significantly relieved the mechanical allodynia and ameliorated depressive-like behavior in DNP rats. In addition, DNP rats displayed increased activation of microglia in the spinal cord, but not astrocytes. Ammoxetine reduced the microglial activation, accumulation of pro-inflammatory cytokines, and activation of p38 and c-Jun N-terminal kinase (JNK) in the spinal cord of DNP rats. Furthermore, ammoxetine displayed anti-inflammatory effects upon challenge with LPS in BV-2 microglia cells.

Conclusion

Our results suggest that ammoxetine may be an effective treatment for relieving DNP symptoms. Moreover, a reduction in microglial activation and pro-inflammatory release by inhibiting the p-p38 and p-JNK pathways is involved in the mechanism.

Metabolic Syndrome, Anxiety and Depression in a Sample of Italian Primary Care Patients

This cross-sectional study aimed at measuring the correlation and association of anxiety, depression and comorbid anxiety-depression symptoms with metabolic syndrome (MetS) in a sample of Italian primary care patients who attended their General Practitioner clinics over a 1-month period in 2013. The Hospital Anxiety and Depression Scale (HADS) was used to assess anxiety and depressive symptoms. The sample was made up of 129 patients (57% women; mean age, 61 ± 12 years). The prevalence of MetS varied from 40% (Adult Treatment Panel III-Revised criteria) to 48% (International Diabetes Federation criteria). The prevalence of symptoms of anxiety, depression and comorbid anxiety and depression was, respectively, 26%, 2%, and 15%. MetS (defined according to Adult Treatment Panel III-Revised criteria) was associated with comorbid anxiety-depressive symptoms (odds ratio [OR] = 3.84, 95% confidence interval [CI] = 1.26-11.71), but not with anxiety or depressive symptoms only. Out of the individual components of MetS, enlarged waist circumference was associated with anxiety symptoms (OR = 4.22, 95% CI = 1.56-11.44).

Molecular changes associated with escitalopram response in a stress-based model of depression

Converging evidence points at hypothalamus-pituitary-adrenal (HPA) axis hyperactivity and neuroinflammation as important factors involved in the etiopathogenesis of major depressive disorder (MDD) and in therapeutic efficacy of antidepressants. In this study, we examined the molecular effects associated with a response to a week-long treatment with escitalopram in the chronic escape deficit (CED) model, a validated model of depression based on the induction of an escape deficit after exposure of rats to an unavoidable stress. We confirmed our previous result that a treatment with escitalopram (10mg/kg) was effective after 7days in reverting the stress-induced escape deficit in approximately 50% of the animals, separating responders from non-responders. Expression of markers of HPA axis functionality as well as several inflammatory mediators were evaluated in the hypothalamus, a key structure integrating signals from the neuro, immune, endocrine systems. In the hypothalamus of responder animals we observed a decrease in the expression of CRH and its receptors and an increase in GR protein in total and nuclear extracts; this effect was accompanied by a significant decrease in circulating corticosterone in the same cohort. Hypothalamic IL-1β and TNFα expression were increased in stressed animals, while CXCL2, IL-6, and ADAM17 mRNA levels were decreased in escitalopram treated rats regardless of the treatment response. These data suggest that efficacy of a one week treatment with escitalopram may be partially mediated by a decrease HPA axis activity, while in the hypothalamus the drug-induced effects on the expression of immune modulators did not correlate with the behavioural outcome.

Immune-Neuroendocrine Interactions: Evolution, Ecology, and Susceptibility to Illness

The integration between immune and neuroendocrine systems is crucial for maintaining homeostasis from invertebrates to humans. In the first, the phagocytic cell, i.e., the immunocyte, is the main actor, while in the latter, the principle player is the lymphocyte. Immunocytes are characterized by the presence of pro-opiomelanocortin (POMC) peptides, CRH, and other molecules that display a significant similarity to their mammalian counterparts regarding their functions, as both are mainly involved in fundamental functions such as immune (chemotaxis, phagocytosis, cytotoxicity, etc.) and neuroendocrine (stress) responses. Furthermore, the immune-neuroendocrine system provides vital answers to ecological and immunological demands in terms of economy and efficiency. Finally, susceptibility to disease emerges as the result of a continuous dynamic interaction between the world within and the world outside. New fields such as ecological immunology study the susceptibility to pathogens in an evolutionary perspective while the field of neuro-endocrine-immunology studies the susceptibility from a more immediate perspective.

Anti-inflammatory treatment for major depressive disorder: implications for patients with an elevated immune profile and non-responders to standard antidepressant therapy

Major depressive disorder (MDD) is a prevalent and disabling psychiatric disease with rates of non-responsiveness to antidepressants ranging from 30-50%. Historically, the monoamine depletion hypothesis has dominated the view on the pathophysiology of depression. However, the lack of responsiveness to antidepressants and treatment resistance suggests that additional mechanisms might play a role. Evidence has shown that a subgroup of depressive patients may have an underlying immune deregulation that could explain the lack of therapeutic benefit from antidepressants. Stimuli like inflammation and infection can trigger the activation of microglia to release pro-inflammatory cytokines, acting on two main pathways: (1) activation of the hypothalamic-pituitary adrenal axis, generating an imbalance in the serotonergic and noradrenergic circuits; (2) increased activity of the enzyme indoleamine-2,3-dioxygenase, resulting in depletion of serotonin levels and the production of quinolinic acid. If this hypothesis is proven true, the subgroup of MDD patients with increased levels of pro-inflammatory cytokines, mainly IL-6, TNF-α and IL-1β, might benefit from an anti-inflammatory intervention. Here, we discuss the pre-clinical and clinical studies that have provided support for treatment with non-steroidal anti-inflammatory drugs in depressed patients with inflammatory comorbidities or an elevated immune profile, as well as evidences for anti-inflammatory properties of standard antidepressants.

Fluoxetine treatment affects the inflammatory response and microglial function according to the quality of the living environment

It has been hypothesized that selective serotonin reuptake inhibitors (SSRIs), the most common treatment for major depression, affect mood through changes in immune function. However, the effects of SSRIs on inflammatory response are contradictory since these act either as anti- or pro-inflammatory drugs. Previous experimental and clinical studies showed that the quality of the living environment moderates the outcome of antidepressant treatment. Therefore, we hypothesized that the interplay between SSRIs and the environment may, at least partially, explain the apparent incongruence regarding the effects of SSRI treatment on the inflammatory response. In order to investigate such interplay, we exposed C57BL/6 mice to chronic stress to induce a depression-like phenotype and, subsequently, to fluoxetine treatment or vehicle (21days) while being exposed to either an enriched or a stressful condition. At the end of treatment, we measured the expression levels of several anti- and pro-inflammatory cytokines and inflammatory mediators in the whole hippocampus and in isolated microglia. We also determined microglial density, distribution, and morphology to investigate their surveillance state. Results show that the effects of fluoxetine treatment on inflammation and microglial function, as compared to vehicle, were dependent on the quality of the living environment. In particular, fluoxetine administered in the enriched condition increased the expression of pro-inflammatory markers compared to vehicle, while treatment in a stressful condition produced anti-inflammatory effects. These findings provide new insights regarding the effects of SSRIs on inflammation, which may be crucial to devise pharmacological strategies aimed at enhancing antidepressant efficacy by means of controlling environmental conditions.

Hypothalamic expression of inflammatory mediators in an animal model of binge eating

Binge eating episodes are characterized by uncontrollable, distressing eating of a large amount of highly palatable food and represent a central feature of bingeing related eating disorders. Research suggests that inflammation plays a role in the onset and maintenance of eating-related maladaptive behavior. Markers of inflammation can be selectively altered in discrete brain regions where they can directly or indirectly regulate food intake. In the present study, we measured expression levels of different components of cytokine systems (IL-1, IL-6, IL-18, TNF-α and IFN-ɣ) and related molecules (iNOS and COX2) in the preoptic and anterior-tuberal parts of the hypothalamus of a validated animal model of binge eating. In this animal model, based on the exposure to both food restriction and frustration stress, binge-like eating behavior for highly palatable food is not shown when animals are exposed to the frustration stress during the estrus phase. We found a characteristic down-regulation of the IL-18/IL-18 receptor system (with increased expression of the inhibitor of the pro-inflammatory cytokine IL-18, IL-18BP, together with a decreased expression of the binding chain of the IL-18 receptor) and a three-fold increase in the expression of iNOS specifically in the anterior-tuberal region of the hypothalamus of animals that develop a binge-like eating behavior. Differently, when food restricted animals were stressed during the estrus phase, IL-18 expression increased, while iNOS expression was not significantly affected. Considering the role of this region of the hypothalamus in controlling feeding related behavior, this can be relevant in eating disorders and obesity. Our data suggest that by targeting centrally selected inflammatory markers, we may prevent that disordered eating turns into a full blown eating disorder.

The Immune System and the Role of Inflammation in Perinatal Depression

Major depression during pregnancy is a common psychiatric disorder that arises from a complex and multifactorial etiology. Psychosocial stress, sex, hormones, and genetic vulnerability increase the risk for triggering mood disorders. Microglia and toll-like receptor 4 play a crucial role in triggering wide and varied stress-induced responses mediated through activation of the inflammasome; this leads to the secretion of inflammatory cytokines, increased serotonin metabolism, and reduction of neurotransmitter availability along with hypothalamic-pituitary-adrenal axis hyperactivity. Dysregulation of this intricate neuroimmune communication network during pregnancy modifies the maternal milieu, enhancing the emergence of depressive symptoms and negative obstetric and neuropsychiatric outcomes. Although several studies have clearly demonstrated the role of the innate immune system in major depression, it is still unclear how the placenta, the brain, and the monoaminergic and neuroendocrine systems interact during perinatal depression. Thus, in the present review we describe the cellular and molecular interactions between these systems in major depression during pregnancy, proposing that the same stress-related mechanisms involved in the activation of the NLRP3 inflammasome in microglia and peripheral myeloid cells in depressed patients operate in a similar fashion in the neuroimmune placenta during perinatal depression. Thus, activation of Toll-like receptor 2 and 4 signaling and the NLRP3 inflammasome in placental immune cells may promote a shift of the Th1/Th2 bias towards a predominant Th1/Th17 inflammatory response, associated with increased secretion of pro-inflammatory cytokines, among other secreted autocrine and paracrine mediators, which play a crucial role in triggering and/or exacerbating depressive symptoms during pregnancy.

Systemic effects of fluoxetine on the amount of tooth movement, root resorption, and alveolar bone remodeling during orthodontic force application in rat

Background:

Antidepressant drugs such as fluoxetine are of the most commonly used drugs among the public. These drugs may impact the regulation of bone cell functioning, and thus affect orthodontic tooth movement. The aim of this study was to determine the effect of fluoxetine on tooth movements during orthodontic treatment in rats.

Materials and Methods:

In this study, 30 male rats were randomly assigned into two groups and injected with fluoxetine 10 mg/kg (experimental group) and normal saline (control group) for a period of 1-month intraperitoneally 5 times/week. Then, the rats were anesthetized and a nickel-titanium closed-coil spring was placed between the left maxillary first molar and left maxillary central incisors of all samples, and then fluoxetine (experimental group) and normal saline (control group) were injected for another 3 weeks by the same method. After measuring tooth movements, rats were sacrificed, and histomorphometric analyses were conducted and the obtained data were statistically analyzed using independent t-test and the significance was set at 0.05.

Results:

Following the fluoxetine injection, the mean amount of tooth movements in the experimental group was reduced compared to the control group, which was not statistically significant (P = 0.14). There was no significant difference between the two groups regarding bone apposition rate (P = 0.83), external root resorption rate (P = 0.1), and mean number of root resorption lacunae (P = 0.16).

Conclusion:

Within the limitations of this study, systemic use of fluoxetine may cause insignificant reduction of tooth movement rate in rats; however, this subject needs more evaluations.

The association of antidepressant medications and diabetic retinopathy among people with diabetes

OBJECTIVE

To determine if the use of antidepressants was associated with lower odds of diabetic retinopathy and if so, to determine if this association was mediated by decreased inflammation as measured by C-reactive protein (CRP).

DESIGN

This was a cross sectional study of 1,041 participants with type 2 diabetes 40-85years old from the 2005-2008 National Health and Nutrition Examination Survey (NHANES). Multiple logistic regression was used to examine the association between the outcome of diabetic retinopathy and the primary exposure of antidepressant medication usage. We also determined whether CRP meets standard criteria as a mediator between antidepressant use and diabetic retinopathy.

RESULTS

Participants using antidepressants were less likely to have diabetic retinopathy (OR 0.50, 95% CI: 0.31-0.82). CRP did not meet one of the criteria for mediation. However, CRP was an effect modifier such that the association of antidepressant use and diabetic retinopathy was only present among participants with CRP ≥0.3mg/dl. Among the antidepressant drug classes, selective serotonin reuptake inhibitor (SSRI) users had significantly lower odds of developing diabetic retinopathy compared to non-users of antidepressants.

CONCLUSIONS

Using representative survey data of US adults with type-2 diabetes, this study found that antidepressant use was associated with lower odds of diabetic retinopathy. Further longitudinal and experimental studies are necessary to confirm this finding and to determine if there is a role for antidepressants in preventing diabetic retinopathy in select patient populations.

Chronic fluoxetine treatment attenuates post-septic affective changes in the mouse

It has been previously demonstrated that the induction of sepsis in rodents results in persistent impairments in affective and cognitive domains. In this study we have examined the impact of chronic treatment with the antidepressant fluoxetine on affective behaviours and hippocampal neuroinflammation and stem cell proliferation in animals that have previously undergone sepsis induced by peripheral treatment with lipopolysaccharide. We find that fluoxetine significantly attenuates post-septic increases in behavioural despair and motivated exploration, whilst also reversing the effects of previous sepsis on activated microglia and stem cell proliferation. These results indicate that conventional antidepressants may be effective in the management of mood disorders in survivors of sepsis.

Microglial NLRP3 inflammasome activation mediates IL-1β-related inflammation in prefrontal cortex of depressive rats

Depression is an inflammatory disorder. Pro-inflammatory cytokine interleukin-1 beta (IL-1β) may play a pivotal role in the central nervous system (CNS) inflammation of depression. Here, we investigated IL-1β alteration in serum, cerebrospinal fluid (CSF) and prefrontal cortex (PFC) of chronic unpredictable mild stress (CUMS)-exposed rats, a well-documented model of depression, and further explored the molecular mechanism by which CUMS procedure induced IL-1β-related CNS inflammation. We showed that 12-week CUMS procedure remarkably increased PFC IL-1β mRNA and protein levels in depressive-like behavior of rats, without significant alteration of serum and CSF IL-1β levels. We found that CUMS procedure significantly caused PFC nuclear factor kappa B (NF-κB) inflammatory pathway activation in rats. The intriguing finding in this study was the induced activation of nucleotide binding and oligomerization domain-like receptor family pyrin domain-containing 3 (NLRP3) inflammasome with the increased IL-1β maturation in PFC of CUMS rats, suggesting a new grade of regulatory mechanism for IL-1β-related CNS inflammation. Moreover, microglial activation and astrocytic function impairment were observed in PFC of CUMS rats. The increased co-location of NLRP3 and ionized calcium binding adaptor molecule 1 (Iba1) protein expression supported that microglia in glial cells was the primary contributor for CUMS-induced PFC NLRP3 inflammasome activation in rats. These alterations in CUMS rats were restored by chronic treatment of the antidepressant fluoxetine, indicating that fluoxetine-mediated rat PFC IL-1β reduction involves both transcriptional and post-transcriptional regulatory mechanisms. These findings provide in vivo evidence that microglial NLRP3 inflammasome activation is a mediator of IL-1β-related CNS inflammation during chronic stress, and suggest a new therapeutic target for the prevention and treatment of depression.

Toll-like receptor 4: innate immune regulator of neuroimmune and neuroendocrine interactions in stress and major depressive disorder

Major depressive disorder (MDD) poses one of the highest disease burdens worldwide. Yet, current treatments targeting serotonergic and noradrenaline reuptake systems are insufficient to provide long-term relief from depressive symptoms in most patients, indicating the need for new treatment targets. Having the ability to influence behavior similar to depressive symptoms, as well as communicate with neuronal and neuroendocrine systems, the innate immune system is a strong candidate for MDD treatments. Given the complex nature of immune signaling, the main question becomes: What is the role of the innate immune system in MDD? The current review presents evidence that toll-like receptor 4 (TLR4), via driving both peripheral and central immune responses, can interact with serotonergic neurotransmission and cause neuroendocrine disturbances, thus integrating with widely observed hallmarks of MDD. Additionally, through describing the multi-directional communication between immune, neural and endocrine systems in stress, TLR4—related mechanisms can mediate stress-induced adaptations, which are necessary for the development of MDD. Therefore, apart from exogenous pathogenic mechanisms, TLR4 is involved in immune changes as a result of endogenous stress signals, playing an integral part in the pathophysiology, and could be a potential target for pharmacological treatments to improve current interventions for MDD.