The influence of mianserin on TNF-α, IL-6 and IL-10 serum levels in rats under chronic mild stress

Can selective serotonin reuptake inhibitors/serotonin and norepinephrine reuptake inhibitor antidepressants decrease the "cytokine storm" in the course of COVID-19 pneumonia?

BACKGROUND

Lots of research has been conducted to fight COVID-19 since the outbreak of the pandemic in 2020. The role of "cytokine storm" in the pathogenesis of COVID-19 pneumonia is well known. Relationship between interleukins and depression is still subject matter of the research, but a correlation between interleukin-6 and depressive disorders is proven by now. The aim of this study is to verify differences among interleukin-6 blood levels of inpatients treated with selective serotonin reuptake inhibitors and/or serotonin and norepinephrine reuptake inhibitor before and during hospitalization and of inpatients not treated with these drugs.

METHODS

This is an observational study performed during the first wave of SARS Cov-2 pandemic in Italy for three months. The hospitalized patients of Internal Medicine wards and Infectious and Tropical Diseases ward of Azienda Ospedaliero-Universitaria Careggi of Florence for COVID-19 pneumonia have been divided into two subgroups (treated / not treated with antidepressants). Patients admitted to Intensive Care Unit previously have been excluded. Each patient has been evaluated concerning demographic, clinical and therapeutic features. The first dosage of interleukin-6 detected during hospitalization has been noticed.

RESULTS

The entire sample included 402 patients and 8.5% (N.=34) had been treated with an antidepressant of the two considered categories before admission until discharge from hospital. Significant lower levels of interleukin-6 of recovered patients of the treated subgroup have been highlighted as compared to recovered patients of not-treated subgroup (12.1 vs. 25.4 P<0.001). These results have been pointed out in spite of higher mean age and more serious comorbidities of the treated subgroup. Nevertheless, the incidence of severe acute respiratory distress syndrome is significantly lower in the subgroup of patients with antidepressant treatment (20.6% vs. 43.2% P<0.02) as well as endotracheal intubation employment (0.0% vs. 11.7% P<0.04). The rate of deceased patients of treated-subgroup is not significantly lower than the rate of not-treated subgroup (23.5% vs. 26.4% P=0.13).

CONCLUSIONS

During COVID-19 pneumonia, the production of interleukin-6 seems to be modulated in presence of antidepressant therapy. Further proofs and broader surveys are necessary.

Effect of Plant Extracts Combinations on TNF-α, IL-6 and IL-10 Levels in Serum of Rats Exposed to Acute and Chronic Stress

Oxydative stress, anxiety and depression are associated with changes in cytokine levels. Natural products, including individual and combined plant extracts, have the potential to be used in the treatment of neuropsychiatric disorders. The goal of this study is to investigate the effects of two combined plant extracts, rich in flavonoids, on the levels of the cytokines TNF-α, IL-6, and IL-10 in rats subjected to models of acute cold stress and chronic unpredictable stress. The study utilized common medicinal plants such as Valeriana officinalis, Melissa officinalis, Crataegus monogyna, Hypericum perforatum, and Serratula coronata, which were combined in two unique combinations-Antistress I and Antistress II. The compositions of the used extracts were determined by HPLC methods. Pro- and anti-inflammatory cytokines in rats' serum were measured with Enzyme-linked immunosorbent assay. The results from the acute stress model revealed that the individual extract of Crataegus monogyna decreased levels of TNF-α, while Serratula coronata, Hypericum perforatum, and Valeriana officinalis effectively reduced IL-6 levels. Both combinations, Antistress I and Antistress II, were effective in reducing TNF-α and IL-6 levels, with Antistress II also increasing IL-10 levels. In the chronic stress model, Hypericum perforatum extract decreased the levels of the pro-inflammatory cytokines TNF-α and IL-6, whereas extracts of Serratula coronata and Valeriana officinalis only reduced TNF-α levels. The two combined extracts, Antistress I and Antistress II, decreased TNF-α and IL-6 levels, while Antistress I also reduced the levels of the anti-inflammatory cytokine IL-10. The combinations of plant extracts used in our experiment have not been previously studied or documented in the available literature. However, based on our own experimental results, we can draw the conclusion that the combinations exhibit a more pronounced effect in reducing cytokine levels compared to the individual plant extracts.

Chronic stress negatively impacts wound healing, welfare, and stress regulation in internally tagged Atlantic salmon (Salmo salar)

The desire to understand fish welfare better has led to the development of live monitoring sensor tags embedded within individuals for long periods. Improving and understanding welfare must not come at the cost of impaired welfare due to a tag’s presence and implantation process. When welfare is compromised, the individual will experience negative emotions such as fear, pain, and distress, impacting the stress response. In this study, Atlantic salmon (Salmo salar) underwent surgical implantation of a dummy tag. Additionally, half of this group was introduced to daily crowding stress. Both groups and an untagged group were followed for 8 weeks using triplicate tanks per group. Sampling took place once a week, and where stress was given, it was conducted 24 h before sampling. Stress-related measurements were taken to understand if tagging caused chronic stress and explore the chronic stress response and its impact on wound healing. Primary stress response hormones measured included CRH, dopamine, adrenocorticotropic hormone, and cortisol. Secondary stress response parameters measured included glucose, lactate, magnesium, calcium, chloride, and osmolality. Tertiary stress response parameters measured included weight, length, and five fins for fin erosion. Wound healing was calculated by taking the incision length and width, the inflammation length and width, and the inside wound length and width. The wound healing process showed that stressed fish have a larger and longer-lasting inflammation period and a slower wound healing process, as seen from the inside wound. The tagging of Atlantic salmon did not cause chronic stress. In contrast, daily stress led to an allostatic overload type two response. ACTH was elevated in the plasma after 4 weeks, and cortisol followed elevation after 6 weeks, highlighting a breakdown of the stress regulation. Fin erosion was elevated alongside cortisol increase in the stressed group. This data suggests that tagging previously unstressed fish in a controlled environment does not negatively affect welfare regarding stress responses. It also indicates that stress delays wound healing and increases the inflammatory response, highlighting how continued stress causes a breakdown in some stress responses. Ultimately, the tagging of Atlantic salmon can be successful under certain conditions where proper healing is observed, tag retention is high, and chronic stress is not present, which could allow for the possible measurement of welfare indicators via smart-tags.

Type 1 interferon mediates chronic stress-induced neuroinflammation and behavioral deficits via complement component 3-dependent pathway

Chronic stress is a major risk factor in the pathophysiology of many neuropsychiatric disorders. Further, chronic stress conditions can promote neuroinflammation and inflammatory responses in both humans and animal models. Type I interferons (IFN-I) are critical mediators of the inflammatory response in the periphery and responsible for the altered mood and behavior. However, the underlying mechanisms are not well understood. In the present study, we investigated the role of IFN-I signaling in chronic stress-induced changes in neuroinflammation and behavior. Using the chronic restraint stress model, we found that chronic stress induces a significant increase in serum IFNβ levels in mice, and systemic blockade of IFN-I signaling attenuated chronic stress-induced infiltration of macrophages into prefrontal cortex and behavioral abnormalities. Furthermore, complement component 3 (C3) mediates systemic IFNβ-induced changes in neuroinflammation and behavior. Also, we found significant increases in the mRNA expression levels of IFN-I stimulated genes in the prefrontal cortex of depressed suicide subjects and significant correlation with C3 and inflammatory markers. Together, these findings from animal and human postmortem brain studies identify a crucial role of C3 in IFN-I-mediated changes in neuroinflammation and behavior under chronic stress conditions.

Chronic psychological stress and lower urinary tract symptoms

It is well established that lower urinary tract symptoms (LUTS), particularly urinary urgency and incontinence, cause stress and anxiety for patients. However, there is mounting evidence that the relationship between these two factors is bidirectional and that chronic psychological stress itself can result in the development of symptoms such as urinary frequency, urgency, incontinence, and pelvic pain. This review considers the evidence that such a relationship exists and reviews the literature from clinical and animal studies to identify some of the mechanisms that might be involved. Inflammatory responses induced by chronic stress appear to offer the strongest link to bladder dysfunction. There is overwhelming evidence, both in patients and animal models, for a release of pro-inflammatory cytokines and chemokines during periods of chronic stress. Furthermore, cytokines have been shown to cause bladder dysfunction and pain via actions in the central nervous system and locally in the bladder. In the brain and spinal cord, pro-inflammatory cytokines influence the regulation of micturition pathways by corticotropin-releasing factor (CRF) and its receptors, while peripherally cytokines affect bladder function, directly causing detrusor hypertrophy and afferent nerve hypersensitivity. There is little information on which treatments may have most benefit for stressed/anxious patients with LUTS, but animal studies suggest traditional drugs for overactive bladder (solifenacin, mirabegron) are more effective on LUTS than anxiolytic drugs (fluoxetine, imipramine). The preliminary preclinical data for CRF receptor antagonists is not consistent. A clearer understanding of the mechanisms involved in stress-induced LUTS should provide a basis for improved treatment of this condition.

Beneficial effects of vitamin D on anxiety and depression-like behaviors induced by unpredictable chronic mild stress by suppression of brain oxidative stress and neuroinflammation in rats

The objective of this study was to investigate the protective effects of vitamin D (Vit D) on anxiety and depression-like behaviors induced by unpredictable chronic mild stress and brain tissue oxidative damage criteria and neuroinflammation in rats. The rats were treated as follows: (1) control, (2) UCMS, (3-5) Vit D 100, 1000, and 10,000 iu + UCMS. Rats were subjected to UCMS for a total of 4 weeks. During week 4, they received seven training trials. The brains were then collected to examine inflammation and oxidative stress criteria. Pretreatment with Vit D enhanced performances of the rats in the elevated plus maze (EPM) and open field (OF) and forced swimming test (FST). UCMS also increased MDA and interleukin-6 (IL-6) levels while decreased CAT, SOD, and thiol. Vit D reversed the effects of UCMS. The results of the current research revealed that Vit D improved UCMS-induced anxiety and depression via decreasing brain oxidative stress and inhibiting neuroinflammation.

Systemic Catecholaminergic Deficiency in Depressed Patients with and without Coronary Artery Disease

Background: Stress and depression are known to contribute to coronary artery disease (CAD) with catecholamines (CA), altering the balance to a pro- and anti-inflammatory stetting and potentially playing a key role in the underlying pathophysiology. This study aimed to elucidate the impact of social stress on the CA system and inflammation markers in patients suffering from CAD and depression. Methods: 93 subjects were exposed to the Trier Social Stress Test (TSST). Based on the results of the depression subscale of the Hospital Anxiety and Depression Scale (HADS, German Version) and the presence/absence of CAD, they were divided into four groups. A total of 21 patients suffered from CAD and depression (+D+CAD), 26 suffered from CAD alone (−D+CAD), and 23 suffered from depression only (+D−CAD); another 23 subjects served as healthy controls (−D−CAD). Subjects were registered at 09:00 AM at the laboratory. A peripheral venous catheter was inserted, and after a 60-min-resting period, the TSST was applied. Prior to and 5, 15, 30, and 60 min after the stress test, plasma epinephrine, norepinephrine, and dopamine concentrations (High Performance Liquid Chromatography (HPLC)) were measured together with the inflammation markers interleukin-6 (IL-6) and monocyte chemotactic protein-1 (MCP-1). High-sensitive C-reactive protein (hs-CRP, Enzyme-linked Immunosorbent Assay (ELISA)) was measured prior to TSST. Results: (+D−CAD) and (+D+CAD) patients showed significantly lower epinephrine and dopamine levels compared to the (−D+CAD) and (−D−CAD) participants at baseline (prior to TSST). Over the whole measurement period after the TSST, no inter-group difference was detected. Partial correlation (controlling for age, gender and Body Mass Index (BMI)) revealed a significant direct relation between MCP-1 and norepinephrine (r = 0.47, p = 0.03) and MCP-1 and epinephrine (r = 0.46, p = 0.04) in patients with −D+CAD at rest. Conclusions: The stress response of the CA system was not affected by depression or CAD, whereas at baseline we detected a depression-related reduction of epinephrine and dopamine release independent of CAD comorbidity. Reduced norepinephrine and dopamine secretion in the central nervous system in depression, known as ‘CA-deficit hypothesis’, are targets of antidepressant drugs. Our results point towards a CA-deficit in the peripheral nervous system in line with CA-deficit of the central nervous system and CA exhaustion in depression. This might explain somatic symptoms such as constipation, stomach pain, diarrhoea, sweating, tremor, and the influence of depression on the outcome of somatic illness such as CAD.

Bupropion monotherapy alters neurotrophic and inflammatory markers in patients of major depressive disorder

BACKGROUND

Emerging hypotheses in the pathophysiology of major depressive disorder (MDD) indicate the role of neurotrophic factors and inflammation. This study assessed the association between therapeutic response of bupropion and serum brain-derived neurotrophic factor (BDNF) and tumour necrosis factor-α (TNF-α) levels in patients with MDD.

METHODS

Thirty patients (aged 18 to 60 years) with MDD diagnosed by DSM-5 criteria, with Hamilton Depression Rating scale (HAM-D) score ≥ 20 were included in the study. Patients were given bupropion sustained release (SR) in the doses of 150 mg once daily. All patients were followed up for 12 weeks.

RESULTS

HAM-D score at the start of the treatment was 25.57 ± 1.85 which significantly reduced to 10.8 ± 4.24 at 12 weeks of treatment. The serum BDNF level increased significantly (p < 0.05) from 2.42 ± 0.19 ng/ml to 2.97 ± 0.10 ng/ml and the levels of serum TNF-α reduced significantly (p < 0.05) from 4.45 ± 0.95 pg/ml to 2.11 ± 0.84 pg/ml at 12 weeks of treatment, in responders to treatment.

CONCLUSION

The results of our study suggest that bupropion SR monotherapy is effective and well tolerated in MDD patients with moderate to severe depression, and its therapeutic efficacy is accompanied by an increase in serum BDNF levels and a decrease in serum TNF-α levels.

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.

Immunoregulatory natural compounds in stress-induced depression: An alternative or an adjunct to conventional antidepressant therapy?

The interplay of chronic stress, neuroinflammation and altered immune reactivity has been shown to be important for the pathophysiology of brain disorders such as schizophrenia, depressive disorders and post-traumatic stress disorder. This immuno-inflammatory theory has been extensively studied in the past three decades leading to the formation of the integrative discipline of psychoneuroimmunology. Targeting of the central nervous system by conventional pharmacotherapeutic methods is mainly through modulation of neuroendocrine systems such as the dopaminergic, GABA-ergic, adrenergic and serotoninergic systems. In recent years an increasing number of both experimental and clinical studies have shown that antidepressants can affect the immune system by reducing the production of pro-inflammatory cytokines such as IL-1β, IL-6 and TNF-α. However, due to the serious adverse effects accompanying the chronic administration of psychoactive drugs there is a continuous need to produce novel therapeutics that are both potent and safe. The present review aims to summarize the current knowledge in the field of psychoneuroimmunology and to delineate the main interactions between stress, inflammation, immunity and the brain. Additionally, this paper explores the use of plant-derived molecules that display a strong anti-stress effect and simultaneously modulate the immune response as an alternative or adjuvant to classical antidepressant drugs.

Medial Forebrain Bundle Deep Brain Stimulation Reverses Anhedonic-Like Behavior in a Chronic Model of Depression: Importance of BDNF and Inflammatory Cytokines

Deep brain stimulation (DBS) of the medial forebrain bundle (MFB) displays a promising antidepressant effects in patients with treatment-refractory depression; however, a clear consensus on underlying mechanisms is still enigmatic. Herein, we investigated the effects of MFB-DBS on anhedonic-like behavior using the Froot Loops® consumption in a chronic unpredictable mild stress (CUS) model of depression, biochemical estimation of peripheral and central inflammatory cytokines, stress hormone, and brain-derived neurotrophic factor (BDNF). Seven days of MFB-DBS significantly reversed the 42-day CUS-generated anhedonic-like phenotype (p < 0.02) indicated by an increase in Froot Loops® consumption. Gross locomotor activity and body weight remained unaffected across the different groups. A dramatic augmentation of adrenocorticotropic hormone levels was seen in the plasma and cerebrospinal fluid (CSF) samples of CUS rats, which significantly reduced following MFB-DBS treatment. However, C-reactive protein levels were found to be unaffected. Interestingly, decreased levels of BDNF in the CUS animals were augmented in the plasma, CSF, and hippocampus following MFB-DBS, but remained unaltered in the nucleus accumbens (NAc). While multiplex assay revealed no change in the neuronal levels of inflammatory cytokines including IL-1α, IL-4, IL-10, IL-12, IL-13, and IL-17 in the neuroanatomical framework of the hippocampus and NAc, increased levels of IL-1β, IL-2, IL-5, IL-6, IL-7, IL-18, TNF-α, and INF-γ were seen in these brain structures after CUS and were differentially modulated in the presence of MFB stimulation. Here, we show that there is dysregulation of BDNF and neuroimmune mediators in a stress-driven chronic depression model, and that chronic MFB-DBS has the potential to undo these aberrations.

Timing matters: the interval between acute stressors within chronic mild stress modifies behavioral and physiologic stress responses in male rats

Chronic mild stress can lead to negative health outcomes. Frequency, duration, and intensity of acute stressors can affect health-related processes. We tested whether the temporal pattern of daily acute stressors (clustered or dispersed across the day) affects depression-related physiology. We used a rodent model to keep stressor frequency, duration, and intensity constant, and experimentally manipulated the temporal pattern of acute stressors delivered during the active phase of the day. Adult male Sprague-Dawley rats were exposed to one of three chronic mild stress groups: Clustered: stressors that occurred within 1 hour of each other (n = 21), Dispersed: stressors that were spread out across the active phase (n = 21), and Control: no stressors presented (n = 21). Acute mild stressors included noise, strobe lights, novel cage, cage tilt, wet bedding, and water immersion. Depression-related outcomes included: sucrose preference, body weight, circulating glucocorticoid (corticosterone) concentration after a novel acute stressor and during basal morning and evening times, and endotoxin-induced circulating interleukin-6 concentrations. Compared to control rats, those in the Clustered group gained less weight, consumed less sucrose, had a blunted acute corticosterone response, and an accentuated acute interleukin-6 response. Rats in the Dispersed group had an attenuated corticosterone decline during the active period and after an acute stressor compared to the Control group. During a chronic mild stress experience, the temporal distribution of daily acute stressors affected health-related physiologic processes. Regular exposure to daily stressors in rapid succession may predict more depression-related symptoms, whereas exposure to stressors dispersed throughout the day may predict diminished glucocorticoid negative feedback.

JSH-23 prevents depressive-like behaviors in mice subjected to chronic mild stress: Effects on inflammation and antioxidant defense in the hippocampus

Nuclear factor-kappa B (NF-κB), which is reported to play an important role in the pathogenesis of depression, also has a central role in the genesis and progression of inflammation. Here, we have targeted the nuclear translocation of NF-κB using 4-methyl-N1-(3-phenyl-propyl)-benzene-1,2-diamine (JSH-23) to elucidate its role in depression. We investigated the antidepressant-like effects of JSH-23 in the chronic mild stress (CMS) mouse model, which is a valid, reasonably reliable, and useful model of depression. The antidepressant-like effects of JSH-23 were evaluated using the sucrose preference test (SPT) and the forced swimming test (FST). We also assessed inflammatory markers [interleukin (IL)-6 and tumor necrosis factor-α (TNF-α)] and components of antioxidant defense [superoxide dismutase (SOD) and nuclear factor erythroid-2-related factor 2 (Nrf 2)] in the hippocampus. Fluoxetine, a classical antidepressant, was used in this study as a positive control. Administration of JSH-23 significantly prevented the decreased sucrose preference in the SPT and prevented the increased immobility time in the FST caused by CMS, but had no effect on locomotor activity. Expression of NF-κB p65 protein in the hippocampus was decreased, and elevated levels of IL-6 and TNF-α were reduced, after JSH-23 administration. In addition to its anti-inflammatory effect, JSH-23 treatment increased the expression of SOD and Nrf 2 in the hippocampus, suggesting that it strengthens antioxidant defense. The current study demonstrated that inhibiting the NF-κB signaling cascade using JSH-23 prevented depressive-like behaviors by decreasing inflammation and improving antioxidant defense in the hippocampus. We concluded that NF-κB activation plays an important role in the pathophysiology of depression and that targeting NF-κB signaling may provide a novel and effective therapy for depression. Additional preclinical studies and clinical trials are, however, needed to further elucidate the effects of this therapeutic strategy.

Suppressive immunoregulatory effects of three antidepressants via inhibition of the nuclear factor-κB activation assessed using primary macrophages of carp (Cyprinus carpio)

Antidepressants, having been applied for the treatment of major depressive disorder and other conditions for decades, are among the most commonly detected human pharmaceuticals in the aquatic environment. This study evaluated the immunotoxicity of acute exposure to environmentally relevant concentrations of amitriptyline, fluoxetine and mianserin using an in vitro primary macrophage model isolated from red common carp (Cyprinus carpio), and also explored their potential mechanisms of action. A potential suppressive immunoregulatory effect of antidepressant exposure was suggested based on the observed suppressive effects on oxidative stress parameters, bactericidal activity, NO production, and NO synthase activity, as well as pro-inflammatory cytokine gene expression, and a significant stimulatory effect on anti-inflammatory interleukin-10 and interferon cytokine gene expression and ATPase activities in macrophages after 6h-exposure to three individual antidepressants and a combination thereof. Notably, we also found these effects were significantly associated with a corresponding decrease in nuclear factor-κB (NF-κB) activity after antidepressants exposure, and the NF-κB antagonist significantly restrained the effects of antidepressants on gene expression of cytokines, indicating that antidepressants could alter the response of various immune-associated components via the inhibition of NF-κB. Moreover, time-dependent lethal concentrations of three antidepressants on primary macrophages were firstly determined at mg/L levels, and the synergetic effects of antidepressant mixtures were suggested and in particular, for some parameters including total antioxidant capacity and cytokine genes expression, they could be significantly affected by antidepressants exposure at concentrations as low as 10ng/L, which together thereby revealed the potential risk of antidepressants to aquatic life.

Inflammation and Immune Regulation as Potential Drug Targets in Antidepressant Treatment

Growing evidence supports a mutual relationship between inflammation and major depression. A variety of mechanisms are outlined, indicating how inflammation may be involved in the pathogenesis, course and treatment of major depression. In particular, this review addresses 1) inflammatory cytokines as markers of depression and potential predictors of treatment response, 2) findings that cytokines interact with antidepressants and non-pharmacological antidepressive therapies, such as electroconvulsive therapy, deep brain stimulation and physical activity, 3) the influence of cytokines on the cytochrome (CYP) p450-system and drug efflux transporters, and 4) how cascades of inflammation might serve as antidepressant drug targets. A number of clinical trials have focused on agents with immunmodulatory properties in the treatment of depression, of which this review covers nonsteroidal anti-inflammatory drugs (NSAIDs), cytokine inhibitors, ketamine, polyunsaturated fatty acids, statins and curcumin. A perspective is also provided on possible future immune targets for antidepressant therapy, such as toll-like receptor-inhibitors, glycogen synthase kinase-3 inhibitors, oleanolic acid analogs and minocycline. Concluding from the available data, markers of inflammation may become relevant factors for more personalised planning and prediction of response of antidepressant treatment strategies. Agents with anti-inflammatory properties have the potential to serve as clinically relevant antidepressants. Further studies are required to better define and identify subgroups of patients responsive to inflammatory agents as well as to define optimal time points for treatment onset and duration.

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.

Changes in the levels of kynurenic acid and selected proinflammatory cytokines after pharmacological treatment and electroconvulsive therapy (ECT) in patients with depressive disorder

The aim of the present study was to compare the concentrations of KYNA, 3-OH-KYN and the cytokines TNF-α and IL-6 in patients with depression vs. healthy controls as well as in patients with depression treated pharmacologically vs. those treated using ECT. We also evaluated the relationship between the concentrations of KYNA, 3-OH-KYN and the cytokines TNF-α and IL-6 and clinical improvement measured on the MADRS scale in patients treated pharmacologically and those treated with ECT.

Subjects and methods: The study group comprised 29 patients aged 28 to 60 years with a diagnosis of a major depressive episode. Eleven of the patients received pharmacological treatment and 18 were treated with ECT.

Patients were assayed for serum levels of KYNA and the cytokines IL-6 and TNF-α. Clinical improvement was measured on the MADRS depression rating scale and the clinical global impression (CGI) scale.

Results: Significant differences were found in KYNA levels between depressive patients and healthy controls. Pharmacological treatment significantly contributed to the increase in KYNA levels and ECT – to the increase in TNF-α levels in depressive patients.

Conclusions:

Potential antiinflammatory effects of acupuncture in a chronic stress model of depression in rats

Accumulating evidence indicates that inflammation may contribute to the pathophysiology of depression. Acupuncture in traditional Chinese medicine has been considered an effective treatment for depression. However, whether the mechanisms that underlie the antidepressant effect of acupuncture are related to its antiinflammatory properties remains unclear. In the present study, rats were exposed to chronic unpredictable mild stress (CUMS) for 28 days to induce depressive-like behavior. Body weight, sucrose preference, and locomotor activity in the open field were measured. After the behavioral tests, reverse transcription polymerase chain reaction was used to determine the mRNA expression of proinflammatory cytokines (interleukin-1β [IL-1β], interleukin-6 [IL-6], and tumor necrosis factor-α [TNF-α]), and enzyme-linked immunosorbent assay was used to detect cytokine concentrations. CUMS rats exhibited decrease in body weight, sucrose preference, and locomotor activity in the open field test. Chronic acupuncture and fluoxetine treatment reversed CUMS-induced depressive-like behavior. Compared with control rats, the mRNA and protein expression of IL-1β, IL-6, and TNF-α in the hippocampus and prefrontal cortex and cytokine concentrations in serum significantly increased in CUMS rats. Acupuncture and fluoxetine treatment significantly decreased the levels of proinflammatory cytokines in the hippocampus, prefrontal cortex, and serum. These results suggest that acupuncture has antidepressant-like effects, and its mechanism of action appears to involve the inhibition of proinflammatory cytokines.

Evaluation of anti-inflammatory and analgesic activities of extracts from herb of Chelidonium majus L

The aim of the study was to evaluate analgesic activity ("hot plate" test), anti-inflammatory activity (carrageenan-induced paw edema) and locomotor activity in rats under the influence of three fractions of Chelidonium majus herb extract: full water extract (FWE), protein enriched fraction (PEF), and non-protein fraction (NPF). Effects of the fractions on the level of chosen cytokines and their mRNA levels were also assessed using lipopolysaccharide (LPS) administration as a proinflammatory cue. All fractions and diclofenac did not affect the locomotor activity of rats in comparison with the control group. FWE and PEF three hours after administration showed statistically significant analgesic activities comparable to morphine (p < 0.05). A slight reduction in rat paw edema was observed after three (comparable with diclofenac) and six hours in the NPF group. FWE revealed a statistically significant pro-inflammatory effect after three hours in comparison with the control group. Peripheral IL-1 and IL-4 cytokine concentrations were reduced under FWE and NPF, PEF fractions. The combination of FWE, PEF and NPF together with LPS showed only the effects of LPS. We suggest that protein enriched fraction (PEF) produced centrally mediated (morphine-like) analgesic action, whereas the anti-inflammatory potential was shown only after LPS-induced inflammation. The precise mechanisms involved in the production of anti-nociceptive and anti-inflammatory responses of studied fractions are not completely understood, but they may be caused rather by the presence of protein more than alkaloids-enriched fraction. This fraction of the extract could be used as an alternative therapy for the prevention of inflammatory-related diseases in the future, but further studies are needed.

A pre-conditioning stress accelerates increases in mouse plasma inflammatory cytokines induced by stress

Background

Major depressive disorder is a prevalent disease that is inadequately treated with currently available interventions. Stress increases susceptibility to depression in patients and rodent models. Depression is also associated with aberrant activation of inflammation, such as increases in circulating levels of interleukin (IL)-1β, IL-6, and tumor necrosis factor-α (TNFα). The two main goals of this study were (i) to identify cytokine changes measuring a broad panel of 19 cytokines, and (ii) to test if a pre-conditioning stress altered the inflammatory response to a subsequent stress.

Result

Stress-induced changes in mouse plasma cytokines were measured by multiplex following administration of one or two daily stresses of inescapable foot shocks using the learned helplessness paradigm for modeling depression-like behavior.

Administration of inescapable foot shocks increased plasma levels of IL-1β, IL-6, TNFα, IL-3, IL-10, IL-13, IL-17A, IL-5, GM-CSF, IL-12(p70), IFN-γ, MIP-1α, MIP-1β, IL-1α, IL-2, KC, RANTES and G-CSF, with peak levels occurring in the range of 6 to 12 hr after stress. Pre-conditioning the mice 24 hr before with an equivalent inescapable foot shock stress resulted in similar magnitudes of increases in most cytokines as occurred after a single stress, but accelerated the increase, causing the levels of most cytokines to peak 1 hr after stress. These results demonstrate that a single stress induces the expression of many cytokines, and that sequential, daily stresses accelerates the rate of cytokine production.

Conclusions

Acute stress broadly activates inflammation in mice, and the inflammatory response is more rapid following repeated stress, actions that may contribute to deleterious effects of stress on depression and other stress-linked diseases.

Comparison of stress-induced and LPS-induced depressive-like behaviors and the alterations of central proinflammatory cytokines mRNA in rats

Although proinflammatory cytokine changes in depression have been studied widely, few investigations have searched for specific and common changes in cytokines. In the present study, two animal models of depression were compared: a chronic stress model using forced swim stress and an immune activation model using repeated central lipopolysaccharide (LPS) infusion. The levels of tumor necrosis factor (TNF)-α, interleukin (IL)-1β, and IL-6 mRNA were examined in the brain regions of the prefrontal cortex, amygdala, and hippocampus using real-time polymerase chain reaction (RT-PCR). It was found that both chronic swim stress and repeated central LPS infusion induced depressive-like behaviors, including decreased body weight, reduced saccharin preference, and increased immobility time or shortened latency of immobility in the tail suspension test. Central TNF-α mRNA expression was elevated in both models and central IL-6 mRNA expression was unchanged in both models. Central IL-1β mRNA expression was increased only in the chronic immune activation model. The findings from this study suggest that TNF-α may be a common risk factor for inflammation in depressive disorders.

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.