Tricyclic antidepressants inhibit IL-6, IL-1 beta and TNF-alpha release in human blood monocytes and IL-2 and interferon-gamma in T cells

Simple dysmood disorder, a mild subtype of major depression, is not an inflammatory condition: Depletion of the compensatory immunoregulatory system

BACKGROUND

A recent study conducted by the laboratory of the first author revealed that major depression is composed of two distinct subtypes: major dysmood disorder (MDMD) and simple dysmood disorder (SDMD). The latter is a less severe phenotype with fewer aberrant biological pathways. MDMD, but not SDMD, patients were identified to have highly sensitized cytokine/growth factor networks using stimulated whole blood cultures. However, no information regarding serum cytokines/chemokines/growth factors in SDMD is available.

OBJECTIVES

This case-control study compares 48 serum cytokines/chemokines/growth factors in academic students with SDMD (n = 64) and first episode (FE)-SDMD (n = 47) to those of control students (n = 44) using a multiplex assay.

FINDINGS

Both FE-SDMD and SDMD exhibited a notable inhibition of immune profiles, such as the compensatory immunoregulatory response system (CIRS) and alternative M2 macrophage and T helper-2 (Th-2) profiles. We observed a substantial reduction in the serum concentrations of five proteins: interleukin (IL)-4, IL-10, soluble IL-2 receptor (sIL-2R), IL-12p40, and macrophage colony-stimulating factor. A considerable proportion of the variability observed in suicidal behaviors (26.7 %) can be accounted for by serum IL-4, IL-10, and sIL-2R (all decreased), CCL11 (eotaxin) and granulocyte CSF (both increased). The same biomarkers (except for IL-10), accounted for 25.5 % of the variance in SDMS severity. A significant correlation exists between decreased levels of IL-4 and elevated ratings of the brooding type of rumination.

CONCLUSIONS

SDMD is characterized by the suppression of the CIRS profile, which signifies a disruption of immune homeostasis and tolerance, rather than the presence of an inflammatory response.

The Anti-Inflammatory Potential of Tricyclic Antidepressants (TCAs): A Novel Therapeutic Approach to Atherosclerosis Pathophysiology

Atherosclerosis, a chronic inflammatory disease, is driven by complex molecular mechanisms involving inflammatory cytokines and immune pathways. According to recent research, tricyclic antidepressants (TCAs), which are typically prescribed to treat depressive disorders, have strong anti-inflammatory effects. TCAs, including imipramine and amitriptyline, alter inflammatory signaling cascades, which include lowering the levels pro-inflammatory cytokines like TNF-α, IL-1β, and IL-6 and inhibiting NF-κB activation. By inhibiting the NLRP3 inflammasome and suppressing pathways including JAK/STAT, MAPK, and PI3K, these effects are produced, improving endothelial function and reducing oxidative stress. The intricacy of TCAs' anti-inflammatory actions has demonstrated by the existence of contradictory findings about how they alter IL-6 levels. The dependence of the heterogeneity of the reaction on the use of particular TCAs and experimental settings is shown by the fact that some studies show reduced IL-6 production, while others indicate increases or no changes. This review explores the multifaceted mechanisms through which TCAs modulate inflammatory pathways. TCAs inhibit NF-κB activation, reduce oxidative stress, and suppress the production of key inflammatory mediators, including IL-6 and TNF-α. They also regulate Toll-like receptor (TLR) signaling and NOD-, LRR-, and NLR family pyrin domain-containing protein 3 (NLRP3) inflammasome activation, reducing the release of IL-1β and IL-18, critical drivers of endothelial dysfunction and plaque instability. Given their capacity to target critical inflammatory molecules and pathways, TCAs provide great potential in the therapy of atherosclerosis, particularly for individuals with associated depression and cardiovascular risk factors. Nevertheless, further research is essential to clarify the precise molecular mechanisms, resolve inconsistencies in current findings, and establish the clinical applicability of TCAs as anti-inflammatory agents in atherosclerosis management.

Major depressive disorder, neuroticism, suicidal behaviors, and depression severity are associated with cytokine networks and their intricate interactions with metabolic syndrome

OBJECTIVES

To identify alterations in the immune profiles in outpatients with major depression (MDD), and its associations with key features, such as suicidal ideation, neuroticism, cognitive symptoms, and the depression phenome while accounting for metabolic syndrome (MetS).

METHODS

In this case-control study, we assayed 48 serum cytokines, chemokines, and growth factors in 67 healthy controls and 66 MDD outpatients. Around 50 % of the outpatient MDD and control participants had a diagnosis of MetS.

RESULTS

Ten differentially expressed proteins (DEPs) were upregulated in outpatient MDD (i.e., CXCL12, tumor necrosis factor [TNF]β, platelet-derived growth factor [PDGF], CCL11, interleukins [IL]9, IL4, CCL5, CCL2, CCL4, IL1 receptor antagonist [IL1RN]), indicating an immune and defense response. Six DEPs were downregulated (vascular endothelial growth factor A [VEGFA], IL12, CCL3, colony stimulating factor [CSF]1, IL1B, nerve growth factor [NGF]), indicating lowered neurogenesis and neuron death regulation. Significant interactions between outpatient MDD and MetS caused a) substantial increases in IL4, IL17, TNF, TNFB, CCL2, CCL5, PDGF, IL1RN; and b) downregulation of VEGFA and FGF. A large part of the variance in neuroticism (26 %), suicidal behaviors (23 %), and the MDD phenome (31 %) was predicted by immunological data and interactions between MetS and CCL5, TNFB or VEGFA.

CONCLUSION

Outpatient MDD is characterized by a cytokine profile with neurotoxic potential which partly explains neuroticism, suicidal behaviors, and the phenome's severity. Lowered IL-10 and activated cytokine profiles with neurotoxic potential are characteristics of outpatient MDD and other depression phenotypes, including severe first-episode inpatient MDD. The presence of MetS in outpatient MDD considerably activates immune profiles with neurotoxic potential. Consequently, immune studies in MDD should always be performed in subjects with and without MetS.

The neurodegenerative hypothesis of depression and the influence of antidepressant medications

Depression is a complex neurological disease that holds many theories on its aetiology and pathophysiology. The monoamine strategy of treating depression with medications to increase levels of monoamines in the (extra)synapse, primarily through the inhibition of monoamine transporters, does not always work, as seen in patients that lack a response to multiple anti-depressant exposures, as well as a lack of depressive symptoms in healthy volunteers exposed to monoamine reduction. Depression is increasingly being understood not as a single condition, but as a complex interplay of adaptations in various systems, including inflammatory responses and neurotransmission pathways in the brain. This understanding has led to the development of the neurodegenerative hypothesis of depression. This hypothesis, which is gaining widespread acceptance posits that both oxidative stress and inflammation play significant roles in the pathophysiology of depression. This article is a review of the literature focused on neuroinflammation in depression, as well as summarised studies of anti-inflammatory and antioxidant effects of antidepressants.

The inflammatory underpinning of depression: An historical perspective

Over the last thirty years, substantial evidence has accumulated in support of the hypothesis that dysregulation of inflammatory processes plays a critical role in the pathophysiology of depression. This review traces the evolution of research supporting this link, discussing key findings from several major investigative fronts: Alterations in inflammatory markers associated with depression; Mood changes following the exogenous administration of inflammatory challenges; The anti-inflammatory properties of traditional antidepressants and the promising antidepressant effects of anti-inflammatory drugs. Additionally, it explores how inflammatory processes interact with specific brain regions and neurochemical systems to drive depressive pathology. A thorough analysis of the 100 most-cited experimental studies on the topic ensures a comprehensive, transparent and unbiased collection of references. This methodological approach offers a panoramic view of the inflammation-depression nexus, shedding light on the complexity of its mechanisms and their connections to psychiatric categorizations, symptoms, demographics, and life events. Synthesizing insights from this extensive research, the review presents an integrative model of the biological foundations of inflammation-associated depression. It posits that we have reached a critical juncture where the translation of this knowledge into personalized immunomodulatory treatments for depression is not just possible, but imperative.

The Changes of Blood and CSF Ion Levels in Depressed Patients: a Systematic Review and Meta-analysis

Micronutrient deficiencies and excesses are closely related to developing and treating depression. Traditional and effective antidepressants include tricyclic antidepressants (TCAs), selective serotonin reuptake inhibitors (SSRIs), and lithium. There is no consensus on the fluctuation of zinc (Zn2+), magnesium (Mg2+), calcium (Ca2+), copper (Cu2+), iron (Fe2+), and manganese (Mn2+) ion levels in depressed individuals before and after therapy. In order to determine whether there were changes in blood and cerebrospinal fluid (CSF) levels of these ions in depressed patients compared with healthy controls and depressed patients treated with TCAs, SSRIs, or lithium, we applied a systematic review and meta-analysis. Using the Stata 17.0 software, we performed a systematic review and meta-analysis of the changes in ion levels in human samples from healthy controls, depressive patients, and patients treated with TCAs, SSRIs, and lithium, respectively. By searching the PubMed, EMBASE, Google Scholar, Web of Science, China National Knowledge Infrastructure (CNKI), and WAN FANG databases, 75 published analyzable papers were chosen. In the blood, the levels of Zn2+ and Mg2+ in depressed patients had decreased while the Ca2+ and Cu2+ levels had increased compared to healthy controls, Fe2+ and Mn2+ levels have not significantly changed. After treatment with SSRIs, the levels of Zn2+ and Ca2+ in depressed patients increased while Cu2+ levels decreased. Mg2+ and Ca2+ levels were increased in depressed patients after Lithium treatment. The findings of the meta-analysis revealed that micronutrient levels were closely associated with the onset of depression and prompted more research into the underlying mechanisms as well as the pathophysiological and therapeutic implications.

Differential effects of desvenlafaxine on hot flashes in women with breast cancer taking tamoxifen: a randomized controlled trial

Hot flashes (HF) are a common adverse event of prolonged tamoxifen use in women with estrogen receptor-positive breast cancer, impacting psychiatric health and quality of life. While desvenlafaxine does not interact with tamoxifen, its efficacy and safety in breast cancer patients remain unstudied. This phase 3, four-week, multi-center, three-arm, parallel-group, randomized, double-blind, placebo-controlled trial investigated the efficacy and safety of desvenlafaxine for treating HF in women with breast cancer taking tamoxifen, assessing potential differential effects in patients with psychiatric and inflammatory conditions. Between December 2017 and February 2019, 57 women aged 19 or older, regularly taking tamoxifen as adjuvant therapy, experiencing moderate-to-severe HFs for more than a month, were randomized to receive desvenlafaxine 50 mg/day (D-50), desvenlafaxine 100 mg/day (D-100), or placebo for four weeks. The primary endpoint was the change rate in HF scores over four weeks, with adverse events as a secondary endpoint. Both desvenlafaxine arms demonstrated greater HF score reductions compared to placebo: D-50 (2.20 points/week, 95% CI: 0.71, 3.68) and D-100 (2.34 points/week, 95% CI: 0.92, 3.76). Notably, D-50 arm showed significantly greater efficacy in patients with depression or elevated inflammation. Desvenlafaxine offers an effective and safe treatment regimen for HF in women with breast cancer taking tamoxifen. The presence of depression and inflammation may guide optimal desvenlafaxine dosing. (Trial Registration: ClinicalTrials.gov Identifier: NCT02819921).

Effect of duloxetine on changes in serum proinflammatory cytokine levels in patients with major depressive disorder

OBJECTIVE

Accumulating evidence supports the idea that inflammation may contribute to the pathophysiology of major depressive disorder (MDD). Duloxetine, a serotonin-norepinephrine reuptake inhibitor, exhibits anti-inflammatory effects both in vitro and in vivo. In this study, we investigated the impact of duloxetine on changes in serum proinflammatory cytokine levels among individuals diagnosed with MDD.

METHODS

A cohort of 23 drug-naïve individuals diagnosed with MDD and 23 healthy controls were included in this study. The severity of depressive symptoms was evaluated using the 24-item Hamilton Depression Scale (HAMD-24). A panel of 7 proinflammatory cytokines, including interleukin-1β (IL-1β), IL-2, IL-6, IL-8, IL-12, tumor necrosis factor-α (TNF-α), and interferon-γ (IFN-γ), were quantified using multiplex Luminex assays. The levels of serum cytokines in healthy controls and patients with MDD were compared at baseline. All patients received duloxetine at a dosage range of 40-60 mg/day for a duration of 4 weeks. The HAMD-24 scores and serum cytokine levels were compared before and after duloxetine treatment.

RESULTS

Compared with healthy controls, patients with MDD had significantly greater levels of IL-2, IL-6, IL-8, IL-12, TNF-α, and IFN-γ (P < 0.05). Moreover, there was a significant decrease in HAMD-24 scores observed pre- and post-treatment (t = 13.161, P < 0.001). Furthermore, after 4 weeks of treatment, the serum levels of IL-8 (t = 3.605, P = 0.002), IL-12 (t = 2.559, P = 0.018), and IFN-γ (t = 3.567, P = 0.002) decreased significantly. However, there were no significant differences in other cytokines, including IL-1β, IL-2, IL-6, and TNF-α, before and after treatment (P > 0.05).

CONCLUSIONS

These findings present compelling evidence, potentially for the first time, indicating that duloxetine treatment may effectively reduce the serum concentrations of IL-8, IL-12, and IFN-γ in individuals diagnosed with MDD. However, the precise mechanisms underlying this effect remain unclear and warrant further investigation.

Concomitant Treatment with Doxycycline and Rifampicin in Balb/c Mice Infected with Brucella abortus 2308 Fails to Reduce Inflammation and Motor Disability

Brucellosis is an infection widely distributed around the world, and in some countries it is considered a public health problem. Brucellosis causes insidious symptoms that make it difficult to diagnose. Infection can also trigger chronic pain and neuropsychiatric complications. Antibiotics are not always effective to eradicate infection, contributing to chronicity. We aimed to investigate the effects of antibiotic treatment on proinflammatory cytokines, neurotransmitters, corticosterone, and behavior in a murine model of infecrion of B. abortus strain 2308. Four study groups were created: (a) control; (b) antibiotic control; (c) infected with B. abortus 2308; and (d) infected and treated with rifampicin and doxycycline. We determined B. abortus 2308 colony-forming units (CFUs), the count of dendritic cells, and macrophages in the spleen; serum levels of cytokines and corticosterone; levels of serotonin, dopamine, epinephrine, and norepinephrine in the brain; and equilibrium, physical strength, anxiety, and hopelessness tests. The infected and treated mice group was compared with the control and infected mice to assess whether treatment is sufficient to recover neuroimmunoendocrine parameters. Our results showed that despite the treatment of brucellosis with rifampicin and doxycycline, antibiotic-treated mice showed a persistence of B. abortus 2308 CFUs, an increased count in macrophage number, and higher circulating levels of corticosterone. Furthermore, the levels of IL-12, IL-6, and TNF-α remained higher. We found a decrease in muscular strength and equilibrium concomitant to changes in neurotransmitters in the hippocampus, cerebellum, and frontal cortex. Our data suggest that the remaining bacterial load after antibiotic administration favors inflammatory, neurochemical, and behavioral alterations, partly explaining the widespread and paradoxical symptomatology experienced by patients with chronic brucellosis.

Role of Inflammatory Mechanisms in Major Depressive Disorder: From Etiology to Potential Pharmacological Targets

The involvement of central and peripheral inflammation in the pathogenesis and prognosis of major depressive disorder (MDD) has been demonstrated. The increase of pro-inflammatory cytokines (interleukin (IL)-1β, IL-6, IL-18, and TNF-α) in individuals with depression may elicit neuroinflammatory processes and peripheral inflammation, mechanisms that, in turn, can contribute to gut microbiota dysbiosis. Together, neuroinflammation and gut dysbiosis induce alterations in tryptophan metabolism, culminating in decreased serotonin synthesis, impairments in neuroplasticity-related mechanisms, and glutamate-mediated excitotoxicity. This review aims to highlight the inflammatory mechanisms (neuroinflammation, peripheral inflammation, and gut dysbiosis) involved in the pathophysiology of MDD and to explore novel anti-inflammatory therapeutic approaches for this psychiatric disturbance. Several lines of evidence have indicated that in addition to antidepressants, physical exercise, probiotics, and nutraceuticals (agmatine, ascorbic acid, and vitamin D) possess anti-inflammatory effects that may contribute to their antidepressant properties. Further studies are necessary to explore the therapeutic benefits of these alternative therapies for MDD.

Imipramine Administration in Brucella abortus 2308-Infected Mice Restores Hippocampal Serotonin Levels, Muscle Strength, and Mood, and Decreases Spleen CFU Count

Brucellosis infection causes non-specific symptoms such as fever, chills, sweating, headaches, myalgia, arthralgia, anorexia, fatigue, and mood disorders. In mouse models, it has been associated with increased levels of IL-6, TNF-α, and IFN-γ, a decrease in serotonin and dopamine levels within the hippocampus, induced loss of muscle strength and equilibrium, and increased anxiety and hopelessness. Imipramine (ImiP), a tricyclic antidepressant, is used to alleviate neuropathic pain. This study evaluated the effects of ImiP on Balb/c mice infected with Brucella abortus 2308 (Ba) at 14- and 28-days post-infection. Serum levels of six cytokines (IFN-γ, IL-6, TNF-α, IL-12, MCP-1. and IL-10) were assessed by FACS, while the number of bacteria in the spleen was measured via CFU. Serotonin levels in the hippocampus were analyzed via HPLC, and behavioral tests were conducted to assess strength, equilibrium, and mood. Our results showed that mice infected with Brucella abortus 2308 and treated with ImiP for six days (Im6Ba14) had significantly different outcomes compared to infected mice (Ba14) at day 14 post-infection. The mood was enhanced in the forced swimming test (FST) (p < 0.01), tail suspension test (TST) (p < 0.0001), and open-field test (p < 0.0001). Additionally, there was an increase in serotonin levels in the hippocampus (p < 0.001). Furthermore, there was an improvement in equilibrium (p < 0.0001) and muscle strength (p < 0.01). Lastly, there was a decrease in IL-6 levels (p < 0.05) and CFU count in the spleen (p < 0.0001). At 28 days, infected mice that received ImiP for 20 days (Im20Ba28) showed preservation of positive effects compared to infected mice (Ba28). These effects include the following: (1) improved FST (p < 0.0001) and TST (p < 0.0001); (2) better equilibrium (p < 0.0001) and muscle strength (p < 0.0001); (3) decreased IL-6 levels (p < 0.05); and (4) reduced CFU count in the spleen (p < 0.0001). These findings suggest the potential for ImiP to be used as an adjuvant treatment for the symptoms of brucellosis, which requires future studies.

Periodontal Pathogens and Their Links to Neuroinflammation and Neurodegeneration

Pathogens that play a role in the development and progression of periodontitis have gained significant attention due to their implications in the onset of various systemic diseases. Periodontitis is characterized as an inflammatory disease of the gingival tissue that is mainly caused by bacterial pathogens. Among them, Porphyromonas gingivalis, Treponema denticola, Fusobacterium nucleatum, Aggregatibacter actinomycetemcomitans, and Tannerella forsythia are regarded as the main periodontal pathogens. These pathogens elicit the release of cytokines, which in combination with their virulence factors induce chronic systemic inflammation and subsequently impact neural function while also altering the permeability of the blood-brain barrier. The primary objective of this review is to summarize the existing information regarding periodontal pathogens, their virulence factors, and their potential association with neuroinflammation and neurodegenerative diseases. We systematically reviewed longitudinal studies that investigated the association between periodontal disease and the onset of neurodegenerative disorders. Out of the 24 studies examined, 20 showed some degree of positive correlation between periodontal disease and neurodegenerative disorders, with studies focusing on cognitive function demonstrating the most robust effects. Therefore, periodontal pathogens might represent an exciting new approach to develop novel preventive treatments for neurodegenerative diseases.

Serum cytokines-based biomarkers in the diagnosis and monitoring of therapeutic response in patients with major depressive disorder

BACKGROUND

Several lines of evidence have suggested that cytokines are implicated in the pathophysiology of depression and antidepressant treatment outcome. However, the results are not always congruent and partly contradictory. We therefore examined the serum levels of multiple cytokines in patients with major depressive disorder (MDD), with the aim to identify serum cytokines-based biomarkers for MDD diagnosis and antidepressant response.

METHODS

Fifty-nine patients with MDD and 61 healthy controls were included. The baseline levels of serum cytokines between MDD group and control group were compared, and the discriminative ability of different cytokines in predicting MDD patients from healthy controls was investigated using the receiver operating characteristic (ROC) curve method. The baseline levels of serum cytokines between antidepressant nonresponders and responders were compared, and the discriminative ability of different cytokines in predicting nonresponders from responders was evaluated using the ROC curve method.

RESULTS

Compared to controls, 15 of the 37 serum cytokines were increased, while 8 cytokines were decreased in MDD patients (all P < 0.05). The results of ROC curve showed that the Area Under Curve (AUC) values of 15 cytokines including IL-2, IL-5, IL-6, IL-8, IL-12, IL-13, IL-16, CCL3, CCL4, CCL17, CXCL10, TNF-α, TNF-β, VEGF-C, and FGF basic were greater than 0.7 in discriminating MDD patients from healthy control. Moreover, after 4-week treatment, levels of the 2 cytokines (IL-12 and TSLP) elevated at baseline significantly down-regulated, and levels of the 6 cytokines (IL-5, IL-16, CCL17, CXCL10, TNF-β, and PIGF) decreased at baseline significantly up-regulated (all P < 0.05). Furthermore, a positive relationship was found between TNF-α levels and Hamilton Depression Rating Scale-24 (HAMD-24) scores in patients with MDD at baseline (r = 0.302, P = 0.019). Additionally, compared to responders, nonresponders exhibited decreased levels of IL-1α, IL-5, IL-13, IL-15, VEGF, and ICAM-1 (all P < 0.05). The ROC curve analysis demonstrated that a combined panel of IL-1α, IL-5, and ICAM-1 achieved a high accuracy in discriminating antidepressant nonresponders from responders (AUC = 0.850, sensitivity = 83.3%, specificity = 81.8%).

CONCLUSIONS

These results suggested that alterations in peripheral cytokines levels hold significant promise as biomarkers for MDD diagnosis and antidepressant response.

Inflammation and Mental Health Disorders: Immunomodulation as a Potential Therapy for Psychiatric Conditions

Mood disorders are the leading cause of disability worldwide and their incidence has significantly increased after the COVID-19 pandemic. Despite the continuous surge in the number of people diagnosed with psychiatric disorders, the treatment methods for these conditions remain limited. A significant number of people either do not respond to therapy or discontinue the drugs due to their severe side effects. Therefore, alternative therapeutic interventions are needed. Previous studies have shown a correlation between immunological alterations and the occurrence of mental health disorders, yet immunomodulatory therapies have been barely investigated for combating psychiatric conditions. In this article, we have reviewed the immunological alterations that occur during the onset of mental health disorders, including microglial activation, an increased number of circulating innate immune cells, reduced activity of natural killer cells, altered T cell morphology and functionality, and an increased secretion of pro-inflammatory cytokines. This article also examines key studies that demonstrate the therapeutic efficacy of anti-inflammatory medications in mental health disorders. These studies suggest that immunomodulation can potentially be used as a complementary therapy for controlling psychiatric conditions after careful screening of candidate drugs and consideration of their efficacy and side effects in clinical trials.

Dopamine, Immunity, and Disease

The neurotransmitter dopamine is a key factor in central nervous system (CNS) function, regulating many processes including reward, movement, and cognition. Dopamine also regulates critical functions in peripheral organs, such as blood pressure, renal activity, and intestinal motility. Beyond these functions, a growing body of evidence indicates that dopamine is an important immunoregulatory factor. Most types of immune cells express dopamine receptors and other dopaminergic proteins, and many immune cells take up, produce, store, and/or release dopamine, suggesting that dopaminergic immunomodulation is important for immune function. Targeting these pathways could be a promising avenue for the treatment of inflammation and disease, but despite increasing research in this area, data on the specific effects of dopamine on many immune cells and disease processes remain inconsistent and poorly understood. Therefore, this review integrates the current knowledge of the role of dopamine in immune cell function and inflammatory signaling across systems. We also discuss the current understanding of dopaminergic regulation of immune signaling in the CNS and peripheral tissues, highlighting the role of dopaminergic immunomodulation in diseases such as Parkinson's disease, several neuropsychiatric conditions, neurologic human immunodeficiency virus, inflammatory bowel disease, rheumatoid arthritis, and others. Careful consideration is given to the influence of experimental design on results, and we note a number of areas in need of further research. Overall, this review integrates our knowledge of dopaminergic immunology at the cellular, tissue, and disease level and prompts the development of therapeutics and strategies targeted toward ameliorating disease through dopaminergic regulation of immunity. SIGNIFICANCE STATEMENT: Canonically, dopamine is recognized as a neurotransmitter involved in the regulation of movement, cognition, and reward. However, dopamine also acts as an immune modulator in the central nervous system and periphery. This review comprehensively assesses the current knowledge of dopaminergic immunomodulation and the role of dopamine in disease pathogenesis at the cellular and tissue level. This will provide broad access to this information across fields, identify areas in need of further investigation, and drive the development of dopaminergic therapeutic strategies.

NLRP3 Inflammasome: From Pathophysiology to Therapeutic Target in Major Depressive Disorder

Major depressive disorder (MDD) is a highly prevalent psychiatric disorder, whose pathophysiology has been linked to the neuroinflammatory process. The increased activity of the Nod-like receptor pyrin containing protein 3 (NLRP3) inflammasome, an intracellular multiprotein complex, is intrinsically implicated in neuroinflammation by promoting the maturation and release of proinflammatory cytokines such as interleukin (IL)-1β and IL-18. Interestingly, individuals suffering from MDD have higher expression of NLRP3 inflammasome components and proinflammatory cytokines when compared to healthy individuals. In part, intense activation of the inflammasome may be related to autophagic impairment. Noteworthy, some conventional antidepressants induce autophagy, resulting in less activation of the NLRP3 inflammasome. In addition, the fast-acting antidepressant ketamine, some bioactive compounds and physical exercise have also been shown to have anti-inflammatory properties via inflammasome inhibition. Therefore, it is suggested that modulation of inflammasome-driven pathways may have an antidepressant effect. Here, we review the role of the NLRP3 inflammasome in the pathogenesis of MDD, highlighting that pathways related to its priming and activation are potential therapeutic targets for the treatment of MDD.

Is depression the missing link between inflammatory mediators and cancer?

Patients with cancer are at greater risk of developing depression in comparison to the general population and this is associated with serious adverse effects, such as poorer quality of life, worse prognosis and higher mortality. Although the relationship between depression and cancer is now well established, a common underlying pathophysiological mechanism between the two conditions is yet to be elucidated. Existing theories of depression, based on monoamine neurotransmitter system dysfunction, are insufficient as explanations of the disorder. Recent advances have implicated neuroinflammatory mechanisms in the etiology of depression and it has been demonstrated that inflammation at a peripheral level may be mirrored centrally in astrocytes and microglia serving to promote chronic levels of inflammation in the brain. Three major routes to depression in cancer in which proinflammatory mediators are implicated, seem likely. Activation of the kynurenine pathway involving cytokines, increases tryptophan catabolism, resulting in diminished levels of serotonin which is widely acknowledged as being the hallmark of depression. It also results in neurotoxic effects on brain regions thought to be involved in the evolution of major depression. Proinflammatory mediators also play a crucial role in impairing regulatory glucocorticoid mediated feedback of the hypothalamic-pituitary-adrenal axis, which is activated by stress and considered to be involved in both depression and cancer. The third route is via the glutamatergic pathway, whereby glutamate excitotoxicity may lead to depression associated with cancer. A better understanding of the mechanisms underlying these dysregulated and other newly emerging pathways may provide a rationale for therapeutic targeting, serving to improve the care of cancer patients.

Selective serotonin reuptake inhibitors and inflammatory bowel disease; Beneficial or malpractice

IBD, a chronic inflammatory disease, has been manifested as a growing health problem. No Crohn's and Colitis councils have officially ratified anti-depressants as a routine regimen for IBD patients. However, some physicians empirically prescribe them to rectify functional bowel consequences such as pain and alleviate psychiatric comorbidities. On the other side, SSRIs' prescription is accompanied by adverse effects such as sleep disturbances. Prolonged intermittent hypoxia throughout sleep disturbance such as sleep apnea provokes periodic reductions in the partial oxygen pressure gradient in the gut lumen. It promotes gut microbiota to dysbiosis, which induces intestinal inflammation. This phenomenon and evidence representing the higher amount of serotonin associated with Crohn's disease challenged our previous knowledge. Can SSRIs worsen the IBD course? Evidence answered the question with the claim on anti-inflammatory properties (central and peripheral) of SSRIs and illuminated the other substantial elements (compared to serotonin elevation) responsible for IBD pathogenesis. However, later clinical evidence was not all in favor of the benefits of SSRIs. Hence, in this review, the molecular mechanisms and clinical evidence are scrutinized and integrated to clarify the interfering molecular mechanism justifying both supporting and disproving clinical evidence. Biphasic dose-dependent serotonin behavior accompanying SSRI shifting function when used up for the long-term can be assumed as the parameters leading to IBD patients' adverse outcomes. Despite more research being needed to elucidate the effect of SSRI consumption in IBD patients, periodic prescriptions of SSRIs at monthly intervals can be recommended.

Severe psychiatric disorders and general medical comorbidities: inflammation-related mechanisms and therapeutic opportunities

Individuals with severe psychiatric disorders, such as mood disorders and schizophrenia, are at increased risk of developing other medical conditions, especially cardiovascular and metabolic diseases. These medical conditions are underdiagnosed and undertreated in these patients contributing to their increased morbidity and mortality. The basis for this increased comorbidity is not well understood, possibly reflecting shared risks factors (e.g. lifestyle risk factors), shared biological mechanisms and/or reciprocal interactions. Among overlapping pathophysiological mechanisms, inflammation and related factors, such as dysbiosis and insulin resistance, stand out. Besides underlying the association between psychiatric disorders and cardiometabolic diseases, these mechanisms provide several potential therapeutic targets.

Morinda officinalis oligosaccharides mitigate chronic mild stress-induced inflammation and depression-like behaviour by deactivating the MyD88/PI3K pathway via E2F2

Morinda officinalis oligosaccharides (MOs) are natural herbal extracts that have been shown to exert antidepressant effects. However, the mechanism of this effect remains unclear. Here, we explored the mechanism by which MOs improved experimental depression. Using a chronic mild stress (CMS) murine model, we examined whether MOs could protect against depressive-like behaviour. Lipopolysaccharide (LPS)- and ATP-treated BV2 cells were used to examine the potential mechanism by which MOs mediate the inflammatory response. We found that MOs prevented the CMS-induced reduction in the sucrose preference ratio in the sucrose preference test (SPT) and shortened the immobility durations in both the tail suspension test (TST) and forced swim test (FST). We also noticed that MOs suppressed inflammatory effects by deactivating the MyD88/PI3K pathway via E2F2 in CMS mice or LPS- and ATP-stimulated BV2 cells. Furthermore, overexpression of E2F2 blunted the beneficial effects of MOs in vitro. Collectively, these data showed that MOs exerted antidepressant effects in CMS mice by targeting E2F2-mediated MyD88/PI3K signalling pathway.

A Reciprocal Link Between Gut Microbiota, Inflammation and Depression: A Place for Probiotics?

Depression is a severe mental disorder that places a significant economic burden on public health. The reciprocal link between the trillions of bacteria in the gut, the microbiota, and depression is a controversial topic in neuroscience research and has drawn the attention of public interest and press coverage in recent years. Mounting pieces of evidence shed light on the role of the gut microbiota in depression, which is suggested to involve immune, endocrine, and neural pathways that are the main components of the microbiota-gut-brain axis. The gut microbiota play major roles in brain development and physiology and ultimately behavior. The bidirectional communication between the gut microbiota and brain function has been extensively explored in animal models of depression and clinical research in humans. Certain gut microbiota strains have been associated with the pathophysiology of depression. Therefore, oral intake of probiotics, the beneficial living bacteria and yeast, may represent a therapeutic approach for depression treatment. In this review, we summarize the findings describing the possible links between the gut microbiota and depression, focusing mainly on the inflammatory markers and sex hormones. By discussing preclinical and clinical studies on probiotics as a supplementary therapy for depression, we suggest that probiotics may be beneficial in alleviating depressive symptoms, possibly through immune modulation. Still, further comprehensive studies are required to draw a more solid conclusion regarding the efficacy of probiotics and their mechanisms of action.

Does Low Grade Systemic Inflammation Have a Role in Chronic Pain?

One of the major clinical manifestations of peripheral neuropathy, either resulting from trauma or diseases, is chronic pain. While it significantly impacts patients’ quality of life, the underlying mechanisms remain elusive, and treatment is not satisfactory. Systemic chronic inflammation (SCI) that we are referring to in this perspective is a state of low-grade, persistent, non-infective inflammation, being found in many physiological and pathological conditions. Distinct from acute inflammation, which is a protective process fighting against intruders, SCI might have harmful effects. It has been associated with many chronic non-communicable diseases. We hypothesize that SCI could be a predisposing and/or precipitating factor in the development of chronic pain, as well as associated comorbidities. We reviewed evidence from human clinical studies indicating the coexistence of SCI with various types of chronic pain. We also collated existing data about the sources of SCI and who could have it, showing that those individuals or patients having SCI usually have higher prevalence of chronic pain and psychological comorbidities. We thus elaborate on the need for further research in the connection between SCI and chronic pain. Several hypotheses have been proposed to explain these complex interactions.

Targeting neurotransmitter-mediated inflammatory mechanisms of psychiatric drugs to mitigate the double burden of multimorbidity and polypharmacy

The increased incidence of multimorbidities and polypharmacy is a major concern, particularly in the growing aging population. While polypharmacy can be beneficial, in many cases it can be more harmful than no treatment, especially in individuals suffering from psychiatric disorders, who have elevated risks of multimorbidity and polypharmacy. Age-related chronic inflammation and immunopathologies might contribute to these increased risks in this population, but the optimal clinical management of drug-drug interactions and the neuro-immune mechanisms that are involved warrants further investigation. Given that neurotransmitter systems, which psychiatric medications predominantly act on, can influence the development of inflammation and the regulation of immune function, it is important to better understand these interactions to develop more successful strategies to manage these comorbidities and complicated polypharmacy. I propose that expanding upon research in translationally relevant human in vitro models, in tandem with other preclinical models, is critical to defining the neurotransmitter-mediated mechanisms by which psychiatric drugs alter immune function. This will define more precisely the interactions of psychiatric drugs and other immunomodulatory drugs, used in combination, enabling identification of novel targets to be translated into more efficacious diagnostic, preventive, and therapeutic interventions. This interdisciplinary approach will aid in better precision polypharmacy for combating adverse events associated with multimorbidity and polypharmacy in the future.

Cinnamomum verum-derived O-methoxycinnamaldehyde prevents lipopolysaccharide-induced depressive-like behavior in mice via NFAT mRNA stability in T lymphocytes

BACKGROUND

Depressive-like behaviors are related to inflammatory immune activation. Cinnamomum verum (CV) has anti-inflammatory effects, but the molecular mechanisms underlying the antidepressant effects after immunological activation still remain elusive.

PURPOSE

The aim of the present study was to investigate the effect of CV in improving depressive-like behavior and explore its underlying mechanism in T lymphocytes.

METHODS

Mice were randomly divided into Control, LPS, LPS plus fluoxetine, LPS plus CV, and LPS plus MCA groups. Behavior was evaluated using forced swimming test (FST) and tail suspension test (TST). The experimental group mice were exposed to LPS to induce depressive-like behavior. Cell viability was measured upon treating splenic T lymphocytes and Jurkat T cells with CV. Cytokine activity was measured using ELISA and RT-qPCR. The components of CV were analyzed by HPLC. NFAT expression was evaluated by western blotting, immunofluorescence, and luciferase assay. To verify the half-life of NFAT mRNA, Jurkat cells were treated with actinomycin D for 1.5, 3, and 4.5 h.

RESULTS

CV effectively prevents inflammation-induced depressive-like behaviors. CV dose-dependently decreased protein and mRNA levels of TNFα and IL-2. Inhibition of TNFα and IL-2 production involves an MCA-mediated decrease in NFAT mRNA level, rather than inhibition of nuclear translocation. This mechanism was independent of NFAT transcription inducer p38 MAPK; it can be attributed to the promotion of NFAT mRNA decay.

CONCLUSION

Overall, MCA might be an alternative or adjuvant to existing NFAT-targeting immunosuppressants for clinical prophylaxis or therapy in the context of inflammation-induced depressive disorder or other T-cell-associated inflammatory disorders.

Immune-Regulatory and Molecular Effects of Antidepressants on the Inflamed Human Keratinocyte HaCaT Cell Line

Allergic contact dermatitis (ACD) is a T cell-mediated type of skin inflammation resulting from contact hypersensitivity (CHS) to antigens. There is strong comorbidity between ACD and major depression. Keratinocytes release immunomodulatory mediators including pro-inflammatory cytokines and chemokines, which modulate skin inflammation and are crucial cell type for the development of CHS. Our previous studies showed that fluoxetine and desipramine were effective in suppressing CHS in different mouse strains. However, the immune and molecular mechanisms underlying this effect remain to be explored. The aim of the current study was to determine the immune and molecular mechanisms of action of antidepressant drugs engaged in the inhibition of CHS response in the stimulated keratinocyte HaCaT cell line. The results show that LPS, TNF-α/IFN-γ, and DNFB stimulate HaCaT cells to produce large amounts of pro-inflammatory factors including IL-1β, IL-6, CCL2, and CXCL8. HaCaT stimulation was associated with increased expression of ICAM-1, a cell adhesion molecule, and decreased expression of E-cadherin. Imipramine, desipramine, and fluoxetine suppress the production of IL-1β, CCL2, as well as the expression of ICAM-1. LPS and TNF-α/IFN-γ activate p-38 kinase, but antidepressants do not regulate this pathway. LPS decreases E-cadherin protein expression and fluoxetine normalizes these effects. In summary, the antidepressant drugs examined in this study attenuate the stimulated secretion of pro-inflammatory cytokines, chemokines, and modulate adhesion molecule expression by the HaCaT cell line. Therefore, antidepressants may have some clinical efficacy in patients with ACD and patients with comorbid depression and contact allergy.

Plasma Indoleamine-2,3-Dioxygenase (IDO) is Increased in Drug-Naï ve Major Depressed Patients and Treatment with Sertraline and Ketoprofen Normalizes IDO in Association with Pro-Inflammatory and Immune- Regulatory Cytokines

BACKGROUND

Major Depression Disorder (MDD) is accompanied by an immune response characterized by increased levels of inflammatory and immune-regulatory cytokines and stimulation of indoleamine-2,3-dioxygenase (IDO). There is also evidence that anti-inflammatory drugs may have clinical efficacy in MDD.

METHODS

This study examined a) IDO in association with interferon (IFN)-γ, Interleukin (IL)-4 and Transforming Growth Factor (TGF)-β1 in 140 drug-naïve MDD patients and 40 normal controls; and b) the effects of an eight-week treatment of sertraline with or without ketoprofen (a nonsteroidal antiinflammatory drug) on the same biomarkers in 44 MDD patients.

RESULTS

Baseline IDO, IFN-γ, TGF-β1 and IL-4 were significantly higher in MDD patients as compared with controls. Treatment with sertraline with or without ketoprofen significantly reduced the baseline levels of all biomarkers to levels which were in the normal range (IDO, TGF-β1, and IL-4) or still somewhat higher than in controls (IFN-γ). Ketoprofen add-on had a significantly greater effect on IDO as compared with placebo. The reductions in IDO, IL-4, and TGF-β1 during treatment were significantly associated with those in the BDI-II.

CONCLUSION

MDD is accompanied by activated immune-inflammatory pathways (including IDO) and the Compensatory Immune-Regulatory System (CIRS). The clinical efficacy of antidepressant treatment may be ascribed at least in part to decrements in IDO and the immune-inflammatory response. These treatments also significantly reduce the more beneficial properties of T helper-2 and T regulatory (Treg) subsets. Future research should develop immune treatments that target the immune-inflammatory response in MDD while enhancing the CIRS.

The Anti-inflammatory Effect of the Tricyclic Antidepressant Clomipramine and Its High Penetration in the Brain Might Be Useful to Prevent the Psychiatric Consequences of SARS-CoV-2 Infection

At the time of writing (December 2020), coronavirus disease 2019 (COVID-19) has already caused more than one million deaths worldwide, and therefore, it is imperative to find effective treatments. The “cytokine storm” induced by Severe Acute Respiratory Syndrome-Coronavirus type 2 (SARS-CoV-2) is a good target to prevent disease worsening, as indicated by the results obtained with tocilizumab and dexamethasone. SARS-CoV-2 can also invade the brain and cause neuro-inflammation with dramatic neurological manifestations, such as viral encephalitis. This could lead to potentially incapacitating long-term consequences, such as the development of psychiatric disorders, as previously observed with SARS-CoV. Several pathways/mechanisms could explain the link between viral infection and development of psychiatric diseases, especially neuro-inflammation induced by SARS-CoV-2. Therefore, it is important to find molecules with anti-inflammatory properties that penetrate easily into the brain. For instance, some antidepressants have anti-inflammatory action and pass easily through the blood brain barrier. Among them, clomipramine has shown very strong anti-inflammatory properties in vitro, in vivo (animal models) and human studies, especially in the brain. The aim of this review is to discuss the potential application of clomipramine to prevent post-infectious mental complications. Repositioning and testing antidepressants for COVID-19 management could help to reduce peripheral and especially central inflammation and to prevent the acute and particularly the long-term consequences of SARS-CoV-2 infection.

Selective serotonin reuptake inhibitor attenuates the hyperresponsiveness of TLR2+ and TLR4+ Th17/Tc17-like cells in multiple sclerosis patients with major depression

Elevated frequency of Th17-like cells expressing Toll-like receptors (TLRs) has been recently associated with relapsing-remitting multiple sclerosis (MS) pathogenesis, a chronic inflammatory demyelinating autoimmune disease of the central nervous system. We aimed to investigate the impact of current major depressive disorder (MDD) on the behaviour of these cells following in vitro stimulation with TLR2, TLR4, TLR5 and TLR9 agonists. Here, the level of both cell proliferation and cytokine production related to Th17/Tc17 phenotypes in response to TLR2 (Pam3C) and TLR4 (LPS) ligands was significantly higher in CD4+ and CD8+ T-cell cultures from MS/MDD patients when compared to non-depressed patients. These cytokine levels were positively associated with neurological disabilities in patients. No difference for responsiveness to TLR5 (flagellin) and TLR9 (ODN) agonists was observed. LPS, but not Pam3C, induced significant IL-10 release, mainly in patients without MDD. Interestingly, more intense expression of TLR2 and TLR4 on these cells was observed in MDD patients. Finally, in vitro addition of serotonin and treatment of MDD patients with selective serotonin reuptake inhibitors (SSRIs) reduced the production of Th17/Tc17-related cytokines by CD4+ and CD8+ T cells in response to Pam3C and LPS. However, only SSRI therapy diminished the frequency and intensity of TLR2 and TLR4 expression on circulating CD4+ and CD8+ T cells. In summary, although preliminary, our findings suggest that adverse events that elevate circulating levels of TLR2 and TLR4 ligands can affect MS pathogenesis, particularly among depressed patients.

Complement Has Brains-Do Intracellular Complement and Immunometabolism Cooperate in Tissue Homeostasis and Behavior?

The classical liver-derived and serum-effective complement system is well appreciated as a key mediator of host protection via instruction of innate and adaptive immunity. However, recent studies have discovered an intracellularly active complement system, the complosome, which has emerged as a central regulator of the core metabolic pathways fueling human immune cell activity. Induction of expression of components of the complosome, particularly complement component C3, during transmigration from the circulation into peripheral tissues is a defining characteristic of monocytes and T cells in tissues. Intracellular complement activity is required to induce metabolic reprogramming of immune cells, including increased glycolytic flux and OXPHOS, which drive the production of the pro-inflammatory cytokine IFN-γ. Consequently, reduced complosome activity translates into defects in normal monocyte activation, faulty Th1 and cytotoxic T lymphocyte responses and loss of protective tissue immunity. Intriguingly, neurological research has identified an unexpected connection between the physiological presence of innate and adaptive immune cells and certain cytokines, including IFN-γ, in and around the brain and normal brain function. In this opinion piece, we will first review the current state of research regarding complement driven metabolic reprogramming in the context of immune cell tissue entry and residency. We will then discuss how published work on the role of IFN-γ and T cells in the brain support a hypothesis that an evolutionarily conserved cooperation between the complosome, cell metabolism and IFN-γ regulates organismal behavior, as well as immunity.

Personalized Medicine Using Neuroimmunological Biomarkers in Depressive Disorders

Major depressive disorder (MDD) is associated with increased suicidal risk and reduced productivity at work. Neuroimmunology, the study of the immune system and nervous system, provides further insight into the pathogenesis and outcome of MDD. Cytokines are the main modulators of neuroimmunology, and their levels are somewhat entangled in depressive disorders as they affect depressive symptoms and are affected by antidepressant treatment. The use of cytokine-derived medication as a treatment option for MDD is currently a topic of interest. Although not very promising, cytokines are also considered as possible prognostic or diagnostic markers for depression. The machine learning approach is a powerful tool for pattern recognition and has been used in psychiatry for finding useful patterns in data that have translational meaning and can be incorporated in daily clinical practice. This review focuses on the current knowledge of neuroimmunology and depression and the possible use of machine learning to widen our understanding of the topic.

Brain TNF drives post-inflammation depression-like behavior and persistent pain in experimental arthritis

Patients with rheumatoid arthritis experience chronic pain, depression and fatigue, even when inflammation of the joints is well controlled. To study the relationship between arthritis, depression, and sustained pain when articular inflammation is no longer observed, we tested the hypothesis that brain TNF drives post-inflammation depression-like behavior and persistent pain in experimental arthritis. The murine model of antigen-induced arthritis (AIA) was used to evaluate the effects of knee inflammation on sustained pain and depression-like behavior. We measured joint pain using an automated dynamic plantar algesiometer and depression-like behavior with the tail suspension test. Cytokines were measured by Luminex assay and ELISA. TNF in the brain was blocked by intracerebroventricular injection of anti-TNF antibodies. Histological damage and elevated levels of cytokines were observed in the knee 24 h after antigen treatment, but not at 13 days. Reduced pain thresholds were seen 24 h and 13 days after treatment. Depression-like behavior was observed on day 13. Treatment with the antidepressant imipramine reduced both depression-like behavior and persistent pain. However, blocking joint pain with the analgesic dipyrone did not alter depression-like behavior. Elevated levels of TNF, CCL2, and CXCL-1 were observed in the hippocampus 24 h after treatment, with TNF remaining elevated at day 13. Intracerebroventricular infusion of an anti-TNF antibody blocked depression-like behavior and reduced persistent pain. We have demonstrated that depression-like behavior and pain is sustained in AIA mice after the resolution of inflammation. These changes are associated with elevated levels of TNF in the hippocampus and are dependent upon brain TNF. The findings reveal an important mechanistic link between the expression of chronic pain and depression in experimental arthritis. Furthermore, they suggest treating depression in rheumatoid arthritis may positively impact other debilitating features of this condition.

Imipramine improves visceral sensation and gut barrier in rat models of irritable bowel syndrome

An impaired gut barrier, possibly leading to visceral hypersensitivity has been recently recognized to be one of the pivotal pathophysiology of irritable bowel syndrome (IBS). We previously showed that lipopolysaccharide (LPS), corticotropin-releasing factor (CRF), and repeated water avoidance stress (WAS) induce visceral hypersensitivity and colonic hyperpermeability via pro-inflammatory cytokine signaling (rat IBS models). Although the precise mechanisms of action are unclear, imipramine, a tricyclic antidepressant, improves IBS symptoms, and also has anticytokine properties. In this study, we hypothesized that imipramine improves the gut barrier to ameliorate IBS symptoms. To test this hypothesis, we determined its effects on visceral hypersensitivity and colonic hyperpermeability in rat IBS models. The visceral pain threshold in response to colonic balloon distention was electrophysiologically estimated by abdominal muscle contractions, and colonic permeability was measured by quantifying the absorbed Evans blue in colonic tissue in vivo. Subcutaneous imipramine injection (7, 20, 50 mg/kg) dose-dependently inhibited LPS-induced (1 mg/kg, subcutaneously) visceral hypersensitivity and colonic hyperpermeability. Imipramine also blocked these gastrointestinal (GI) changes induced by CRF (50 μg/kg, intraperitoneally) or repeated WAS (1 h daily for 3 days). Yohimbine (an α₂-adrenoceptors antagonist), sulpiride (a dopamine D₂ receptor antagonist), and naloxone hydrochloride (an opioid receptor antagonist) reversed these effects of imipramine in the LPS model. Therefore, imipramine may block GI changes in IBS via α₂-adrenoceptors, dopamine D₂, and opioid signaling. The improvement in the gut barrier resulting in inhibition of visceral pain is considered a valid mechanism of imipramine to ameliorate IBS symptoms.

Umbelliprenin relieves paclitaxel-induced neuropathy

OBJECTIVES

Umbelliprenin (UMB) is a prenylated coumarin that acts as an in vitro antioxidant and inhibits lipoxygenase managing the inflammation pathways, while in vivo it exerts anti-inflammatory activities.

METHODS

In this study, neuropathic pain was induced by four intraperitoneal doses of 2 mg/kg per day of paclitaxel (PTX) on days 1, 3, 5 and 7. Here, 49 male mice were randomly divided in the following groups: sham (not treated animals), negative control (PTX-treated receiving normal saline), single-dose UMB 6.25, 12.5 and 25 mg/kg groups (PTX-treated receiving UMB 6.25, 12.5 and 25 mg/kg, respectively), prevention (PTX-treated receiving PTX along with UMB 12.5 mg/kg on days 1, 3, 5 and 7) and positive control group (PTX-treated receiving imipramine 10 mg/kg as acute treatment). Hot-plate test was done to assess response to heat. Finally, interleukin (IL)-6 levels in the sciatic nerve and lipid peroxidation in sera were assessed.

KEY FINDINGS

Umbelliprenin was found equally effective for acute treatment with imipramine, when comparing the prevention group and the positive control group. Single, 25 mg/kg UMB effectively attenuated hyperalgesia, lipid peroxidation and IL-6 levels.

CONCLUSIONS

Umbelliprenin alleviated neuropathic pain, and decreased serum IL-6 levels and oxidative stress. UMB deserves further investigations, especially in clinical settings.

The Importance of Marine Omega-3s for Brain Development and the Prevention and Treatment of Behavior, Mood, and Other Brain Disorders

Most of the global population is deficient in long-chain marine omega-3s. In particular, docosahexaenoic acid (DHA), a long-chain omega-3 fatty acid, is important for brain and eye development. Additionally, DHA plays a significant role in mental health throughout early childhood and even into adulthood. In the brain, DHA is important for cellular membrane fluidity, function and neurotransmitter release. Evidence indicates that a low intake of marine omega-3s increases the risk for numerous mental health issues, including Attention Deficit Hyperactivity Disorder (ADHD), autism, bipolar disorder, depression and suicidal ideation. Studies giving supplemental marine omega-3s have shown promise for improving numerous mental health conditions. This paper will review the evidence surrounding marine omega-3s and mental health conditions.

Elevated Circulating Th2 Cells in Women With Asthma and Psychological Morbidity: A New Asthma Endotype?

PURPOSE

Psychological stress shifts the immune system toward the production of T-helper (Th)-2-mediated cytokines and eosinophilia, increases the risks for both asthma and depression, and can precipitate asthma exacerbations. Th2-mediated inflammation is a characteristic of allergic asthma. We have shown that the levels of CD4⁺ Th2 cells in the peripheral blood of patients with asthma are associated with severity and/or control of the disease. To improve our understanding of the interactions between stress and asthma symptoms, we evaluated the effects of psychological comorbidity on Th2-mediated inflammation in patients with asthma.

METHODS

Sixty-six asthmatic patients were recruited from the University of Alberta Asthma Clinic after they gave informed consent. Stress-related effects on asthma and psychological morbidity were assessed using the Asthma Control Questionnaire, completed by the patients at recruitment. Venous blood was collected at recruitment and Th2-mediated immunity evaluated by flow cytometry, quantitative real-time reverse-transcription polymerase chain reaction and enzyme-linked immunosorbent assay.

FINDINGS

Patients with stress-triggered asthma (n = 12) had higher percentage of CD4⁺ T cells (P = 0.006) and Th2 cells (CD4⁺CRTh2⁺ T cells; P = 0.002) in peripheral blood compared to patients with asthma who did not experience stress-related worsening of disease (n = 54). The same was true when we analyzed patients with any form of psychological comorbidity (n = 19) compared to those without psychological comorbidities (n = 47). These differences were evident among women, but not among men. Women with psychological comorbidity also required higher doses of inhaled and oral corticosteroids compared to those without psychological comorbidity.

IMPLICATIONS

Asthma involving psychological morbidity associates with an elevated level of circulating Th2 cells and increased corticosteroid usage, and may be more prevalent in women. Larger-scale prospective studies are required for assessing whether these women constitute a new endotype of Th2-high asthma responsive to treatments aimed to improve psychological comorbidities.

Clomipramine, a tricyclic antidepressant, and selegiline, a monoamine oxidase-B inhibitor, modulate the activity of phagocytic cells after oral administration in mice

OBJECTIVES

Our aim was to find out whether clomipramine, a tricyclic antidepressant, and selegiline, a monoamine oxidase-B inhibitor, influence the activity of phagocytic cells after in-vivo administration in mice.

METHODS

Clomipramine and selegiline were administered to Balb/c mice orally at a dose of 1 mg/kg, 7 or 14 times. IL-1β and nitric oxide (NO) levels were measured in supernatants of the peritoneal macrophage cultures stimulated in vitro with lipopolysaccharide from Escherichia coli. The phagocytic activity of the granulocytes and monocytes was determined using a commercial Phagotest 24 and 72 h after the last dose of the investigated drugs.

KEY FINDINGS

Seven doses of clomipramine or selegiline decreased IL-1β production, while a rise in its synthesis was observed after 14 doses of selegiline. Clomipramine administered 14 times increased NO production. Clomipramine and selegiline administered seven times reduced the percentage of phagocytosing granulocytes. The drugs administered 14 times increased the percentage of phagocytosing granulocytes and decreased the percentage of phagocytosing monocytes.

CONCLUSIONS

Both clomipramine and selegiline administered in vivo changed the phagocytic activity of blood cells and IL-1β and NO production by murine peritoneal macrophages. This effect depended on the drug, the number of doses and the type of phagocytic cells.

Mitigation of Rheumatic Arthritis in a Rat Model via Transdermal Delivery of Dapoxetine HCl Amalgamated as a Nanoplatform: In vitro and in vivo Assessment

Purpose

Dapoxetine HCl (DH), a selective serotonin reuptake inhibitor, may be useful for the treatment of rheumatic arthritis (RA). The purpose of this study was to investigate the therapeutic efficacy of transdermal delivery of DH in transethosome nanovesicles (TENVs). This novel delivery of DH may overcome the drawbacks associated with orally administered DH and improve patient compliance.

Methods

DH-TENV formulations were prepared using an injection- sonication method and optimized using a 3³ Box-Behnken-design with Design Expert^® software. The TENV formulations were assessed for entrapment efficiency (EE-%), vesicle size, zeta potential, in vitro DH release, and skin permeation. The tolerability of the optimized DH-TENV gel was investigated using a rat skin irritation test. A pharmacokinetic analysis of the optimized DH-TENV gel was also conducted in rats. Moreover, the anti-RA activity of the optimized DH-TENV gel was assessed based on the RA-specific marker anti-cyclic cirtullinated peptide antibody (anti-CCP), the cartilage destruction marker cartilage oligomeric matrix protein (COMP) and the inflammatory marker interleukin-6 (IL-6). Level of tissue receptor activator of nuclear factor kappa-Β ligand (RANKL) were also assessed.

Results

The optimized DH-TENV formulation involved spherical nanovesicles that had an appropriate EE- % and skin permeation characteristic. The DH-TENV gel was well tolerated by rats. The pharmacokinetics analysis showed that the optimized DH-TENV gel boosted the bioavailability of the DH by 2.42- and 4.16-fold compared to the oral DH solution and the control DH gel, respectively. Moreover, it significantly reduced the serum anti-CCP, COMP and IL-6 levels and decreased the RANKL levels. Furthermore, the DH-TENV gel attenuated histopathological changes by almost normalizing the articular surface and synovial fluid.

Conclusion

The results indicate that DH-TENVs can improve transdermal delivery of DH and thereby alleviate RA.

Lowered zinc and copper levels in drug-naïve patients with major depression: Effects of antidepressants, ketoprofen and immune activation

Objectives: The aim of the present work is to examine the effects of treatment with sertraline with and without ketoprofen on serum levels of zinc and copper in association with immune-inflammatory biomarkers in drug-naïve major depressed patients.Methods: We measured serum zinc and copper, interleukin (IL)-1β, IL-4, IL-6, IL-18, interferon-γ, and transforming growth factor-β1 in 40 controls and 133 depressed patients. The clinical efficacy of the treatment was measured using the Beck Depression Inventory-II (BDI-II) at baseline and 8 weeks later.Results: We found significantly reduced serum zinc and copper in association with upregulation of all cytokines, indicating activation of the immune-inflammatory responses system (IRS) and the compensatory immune regulatory system (CIRS). Treatment with sertraline significantly increased zinc and decreased copper. During treatment, there was a significant inverse association between serum zinc and immune activation. The improvement in the BDI-II during treatment was significantly associated with increments in serum zinc coupled with attenuation of the IRS/CIRS.Conclusions: Lower zinc is a hallmark of depression, while increments in serum zinc and attenuation of the immune-inflammatory response during treatment appear to play a role in the clinical efficacy of sertraline.

Peripheral cytokine levels and response to antidepressant treatment in depression: a systematic review and meta-analysis

Predicting antidepressant treatment response has been a clinical challenge for major depressive disorder (MDD). The inflammation hypothesis of depression suggests that cytokines play a key role in the pathophysiology of MDD and alterations in peripheral cytokine levels are associated with antidepressant treatment outcome. Present meta-analysis aimed to examine the association between baseline peripheral cytokine levels and the response to antidepressant treatment and to evaluate whether changes of cytokine levels were associated with the response to antidepressant treatment in patients with MDD. Human-based studies published in any language in peer-reviewed journals were systematically searched from the PubMed, Embase and Web of Science databases, from inception up to October 2018. The search terms included cytokine, depressive disorder and antidepressant and their synonyms. Case-control or case-case studies reporting on levels of IL-1β, IL-2, IL-4, IL-5, IL-6, IL-8, IL-10, IL-12, CRP, TNF-α, IFN-γ, GM-CSF, MIP-1α, and Eotaxin-1 in patients with MDD based on validated depression scales both before and after antidepressant treatment were included. Of 7408 identified records, 44 studies met inclusion. Standardized mean differences in each cytokine were evaluated, and random-effects meta-analyses were performed. MDD patients who responded to antidepressant treatment had lower baseline IL-8 levels than the nonresponders (Hedge's g = -0.28; 95%CI, -0.43 to -0.13; P = 0.0003; FDR = 0.004). Antidepressant treatment significantly decreased levels of TNF-α (Hedge's g = 0.60; 95%CI, 0.26-0.94; P = 0.0006; FDR = 0.004) only in responders, and responders showed significantly more decreased TNF-α levels compared with nonresponders (P = 0.046). These findings suggested that alterations in peripheral cytokine levels were associated with antidepressant treatment outcomes in MDD. Further investigations are warranted to elucidate sources of heterogeneity and examine the potentiality of using inflammatory cytokines as novel predictive markers for the pharmacological treatment of MDD.

Differences in the immune-inflammatory profiles of unipolar and bipolar depression

BACKGROUND

Major depressive disorder (MDD) and bipolar depression (BD) both share increased immune-inflammatory activation. However, there are unclear patterns of differences in peripheral immune profiles between them.

METHODS

We examined such differences in 245 MDD and 59 BD patients, recruited in the same center, who were in an acute depressive episode of moderate severity. Hierarchical binary logistic regression analyses and generalized linear models were used to compare levels of plasma biomarkers between groups and to predict dichotomous classification.

RESULTS

Interleukin (IL)-1β, tumor necrosis factor (TNF)-α, soluble TNF receptor (sTNFR)1, IL-12 and IL-10 were significantly higher in MDD than in BD, whereas IL-6, sTNFR2, IL-18, IL-33, ST2 (IL1R Like 1) and KLOTHO were significantly higher in BD than in MDD. Moreover, logistic regression analyses correctly classified BD and MDD patients with 98.1% accuracy, using a combination of IL-6, IL-8, ST2, sTNFR2 (directly associated with BD) and IL-12 and TNF-α (directly associated with MDD). Patients with MDD with melancholic features showed higher IL-1β levels than those without melancholia. The sTNFR1 / sTNFR2 ratio significantly predicted MDD and state and trait anxiety and negative affect. Results remained significant after covariate adjustment, including drug use.

LIMITATIONS

Cross-sectional study. Lack of control comparison group. Differences in exposure to medications among participants.

CONCLUSIONS

Differences in immune profiles between BD and MDD patients exist, especially for the compensatory immune-regulatory system (CIRS): increased IL-10 is the primary immune-regulatory mechanism in MDD, while increased sTNFR2 and KLOTHO are the primary regulatory mechanisms in BD.

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.

Interleukin 6 as a pathogenic factor mediating clinical manifestations and a therapeutic target for rheumatic diseases and depressive disorders

The review summarizes current idea on the key role of interleukin 6 (IL-6) in the pathogenesis of rheumatic diseases (RDs) and depressive disorders. It considers in detail the mechanisms by which IL6 induces the clinical and laboratory manifestations of RDs and depression; the influence of precipitating and predisposing stress factors, including childhood mental traumas, which increase the risk of RDs and depression, on IL-6 production. Particular attention is paid to the consideration of prospects for using IL-6 inhibitors in the therapy of depression.

Effects of SSRIs on peripheral inflammatory markers in patients with major depressive disorder: A systematic review and meta-analysis

INTRODUCTION

Peripheral levels of inflammatory markers are elevated in major depressive disorder (MDD). Selective serotonin reuptake inhibitors (SSRIs) affect levels of inflammatory markers in patients with MDD, but studies have reported inconsistent findings. This systematic review and meta-analysis aims to investigate the effects of SSRI treatment on peripheral levels of a range of inflammatory markers in MDD patients.

METHODS

Systematic literature search (Pubmed, Web of Science, Embase, Cochrane) for studies published before November 2018. Studies were included if they used SSRI monotherapy and peripheral levels of interleukin (IL)-1β, IL-2, IL-4, IL-6, IL-10, tumor necrosis factor (TNF)-α, and interferon (IFN)-γ were measured before and after treatment in patients with MDD. Meta-analysis was conducted using Comprehensive Meta-analysis (version 2). Effect sizes were calculated using bias-corrected standardized mean difference (Hedges' g) between pre- and post-treatment. Sub-group analyses, meta-regression and publication bias estimates were undertaken; sensitivity analyses were performed using different estimated pre- and post-treatment correlations and after removing poor quality studies.

RESULTS

Twenty two eligible studies including 827 MDD patients were included in the meta-analysis: fifteen studies for IL-6; eleven for TNF-α; eight for IL-10; seven for IL-1β; six for IL-4; five for IL-2; and four for IFN-γ. The pooled effect estimate indicates SSRI treatment decreased levels of pro-inflammatory markers IL-6 (Hedges' g, -0.418; 95%CI, -0.663 to -0.174; I² = 89.412), TNF-α (Hedges' g, -0.554; 95%CI, -0.990 to -0.118; I² = 95.438) and IL-1β (Hedges' g = -0.574; 95%CI, -1.014 to -0.135; I² = 91.622), and anti-inflammatory marker IL-10 (Hedges' g = -0.615; 95%CI, -0.989 to -0.242; I² = 90.406). There were no significant treatment effects on levels of IL-2, IL-4, or IFN-γ. There was a high level of heterogeneity between studies. Sensitivity analyses indicated the robustness of the primary analyses.

CONCLUSIONS

The current review and meta-analysis indicates moderate immunomodulating effects of SSRI treatment for MDD, which suggests SSRIs may owe some of their therapeutic effect to their anti-inflammatory properties. High heterogeneity across studies may limit interpretation of the findings and larger randomized clinical trials are warranted.