Effect of celecoxib add-on treatment on symptoms and serum IL-6 concentrations in patients with major depressive disorder: randomized double-blind placebo-controlled study

On 'polypharmacy' and multi-target agents, complementary strategies for improving the treatment of depression: a comparative appraisal

Major depression is a heterogeneous disorder, both in terms of symptoms, ranging from anhedonia to cognitive impairment, and in terms of pathogenesis, with many interacting genetic, epigenetic, developmental and environmental causes. Accordingly, it seems unlikely that depressive states could be fully controlled by a drug possessing one discrete mechanism of action and, in the wake of disappointing results with several classes of highly selective agent, multi-modal treatment concepts are attracting attention. As concerns pharmacotherapy, there are essentially two core strategies. First, multi-target antidepressants that act via two or more complementary mechanisms and, second, polypharmacy, which refers to co-administration of two distinct drugs, usually in separate pills. Both multi-target agents and polypharmacy ideally couple a therapeutically unexploited action to a clinically established mechanism in order to enhance efficacy, moderate side-effects, accelerate onset of action and treat a broader range of symptoms. The melatonin MT1/MT2 agonist and 5-HT(2C) antagonist, agomelatine, which is effective in the short- and long-term treatment of depression, exemplifies the former approach, while evidence-based polypharmacy is illustrated by the adjunctive use of second-generation antipsychotics with serotonin reuptake inhibitors for treatment of resistant depression. Histone acetylation and methylation, ghrelin signalling, inflammatory modulators, metabotropic glutamate-7 receptors and trace amine-associated-1 receptors comprise attractive substrates for new multi-target and polypharmaceutical strategies. The present article outlines the rationale underpinning multi-modal approaches for treating depression, and critically compares and contrasts the pros and cons of established and potentially novel multi-target vs. polypharmaceutical treatments. On balance, the former appear the most promising for the elaboration, development and clinical implementation of innovative concepts for the more effective management of depression.

Overlapping biological mechanisms underlying sickle cell disease, stress, and depression: a stress-vulnerability framework

After participating in this activity, learners should be better able to:1. Evaluate the overlap between sickle cell disease (SCD) and depression.2. Identify sources of psychological stress and biological vulnerabilities toward developing depression in patients with SCD.3. Assess the potential mechanisms underlying SCD, stress, and depression.Depression is a common co-occurring disorder in persons with sickle-cell disease (SCD). Individuals with this chronic illness may be particularly vulnerable to depression. In addition to risk factors for depression specifically related to SCD, these individuals typically experience further psychological stress due to multiple risk factors in their environment. To date, however, little research has focused on the co-occurring biological mechanisms across these conditions and how those mechanisms may interact to produce depressive symptoms. In this review we use a stress-vulnerability framework to describe the sources of psychological stress and the SCD factors that increase the risk of depression. We suggest that several biological factors, such as nitric oxide and cytokines, may play an important role in co-occurring stress, SCD, and depression. The interaction of these factors may be of particular importance for understanding the comorbidity of SCD and depression. Implications for current treatment and future research are discussed.

Celecoxib: a new augmentation strategy for depressive mood episodes. A systematic review and meta-analysis of randomized placebo-controlled trials

OBJECTIVE

The aim of this research was to perform a systematic review to identify all randomized controlled trials (RCTs) evaluating the efficacy and safety of add-on celecoxib for treatment of depressive mood episodes.

METHODS

Four electronic databases were systematically searched from their inception to 8 August 2013: PubMed, Cochrane Library (Cochrane Central Register of Controlled Trials), Scopus, and PsychINFO. Pooled difference in means of Hamilton Depression Rating Scale score, pooled odds ratio (OR) of treatment response, and pooled OR of remission were calculated as the main effect size. A random-effects model was used to pool the data across studies.

RESULTS

Five RCTs (four unipolar depression studies and one bipolar depression study) were included in the systematic review for qualitative data synthesis. Moreover, quantitative results of four RCTs (unipolar depression studies) were meta-analyzed. The add-on celecoxib group had a statistically significant decrease in means of the Hamilton Depression Rating Scale score at week 4 (pooled difference in means=3.3, 95%CI [1.2-5.3], p=0.002) and week 6 (pooled difference in means=3.43, 95%CI [1.9-4.9], p<0.0001). The add-on celecoxib group also showed higher response (pooled OR=6.6, 95%CI [2.5-17], p<0.0001) and remission rates (pooled OR=6.6, 95%CI [2.7-15.9], p<0.0001) compared with the placebo group.

CONCLUSIONS

Celecoxib can be considered as an effective add-on treatment for unipolar depressive patients. Making conclusion regarding the efficacy and safety for longer duration warrants further studies with a larger sample size and longer follow-up duration.

Effectiveness and tolerance of anti-inflammatory drugs' add-on therapy in major mental disorders: a systematic qualitative review

OBJECTIVE

To provide a systematic review of the literature regarding the efficacy of anti-inflammatory drugs in three major mental disorders [major depressive disorder (MDD), schizophrenia and bipolar disorders].

METHOD

Four databases were explored, without any year or language restrictions. The baseline search paradigm was limited to open-labelled clinical and randomized controlled trials (RCTs).

RESULTS

Four major classes of anti-inflammatory drugs were identified, namely polyunsaturated fatty acids (PUFAs), cyclooxygenase (COX) inhibitors, anti-TNFalpha and minocycline. Effectiveness and benefit/risk ratio of each class in MDD, bipolar disorders and schizophrenia was detailed when data were available. Several meta-analyses indicated effectiveness of PUFAs in MDD with a good tolerance profile. One meta-analysis indicated that COX-2 specific inhibitors showed effectiveness in schizophrenia. Anti-TNFalpha showed important effectiveness in resistant MDD with blood inflammatory abnormalities. Minocycline showed effectiveness in schizophrenia.

CONCLUSION

Polyunsaturated fatty acids seem to have the best benefit/risk ratio profile but proved their effectiveness only in MDD. A number of anti-inflammatory drugs are available as adjunct treatment for treatment-resistant patients with MDD, schizophrenia and bipolar disorder. If used with caution regarding their possible side-effects, they may be reasonable therapeutic alternatives for resistant symptomatology.

Treatment-resistant depression: definitions, review of the evidence, and algorithmic approach

BACKGROUND

Most adults with major depressive disorder (MDD) fail to achieve remission with index pharmacological treatment. Moreover, at least half will not achieve and sustain remission following multiple pharmacological approaches. Herein, we succinctly review treatment modalities proven effective in treatment-resistant depression (TRD).

METHODS

We conducted a review of computerized databases (PubMed, Google Scholar) from 1980 to April 2013. Articles selected for review were based on author consensus, adequacy of sample size, the use of a standardized experimental procedure, validated assessment measures and overall manuscript quality.

RESULTS

The evidence base supporting augmentation of conventional antidepressants with atypical antipsychotics (i.e., aripiprazole, quetiapine, and olanzapine) is the most extensive and rigorous of all pharmacological approaches in TRD. Emerging evidence supports the use of some psychostimulants (i.e., lisdexamfetamine) as well as aerobic exercise. In addition, treatments informed by pathogenetic disease models provide preliminary evidence for the efficacy of immune-inflammatory based therapies and metabolic interventions. Manual based psychotherapies remain a treatment option, with the most compelling evidence for cognitive behavioral therapy. Disparate neurostimulation strategies are also available for individuals insufficiently responsive to pharmacotherapy and/or psychosocial interventions.

LIMITATIONS

Compared to non-treatment-resistant depression, TRD has been less studied. Most clinical studies on TRD have focused on pharmacotherapy-resistant depression, with relatively fewer studies evaluating "next choice" treatments in individuals who do not initially respond to psychosocial and/or neurostimulatory treatments.

CONCLUSION

The pathoetiological heterogeneity of MDD/TRD invites the need for mechanistically dissimilar, and empirically validated, treatment approaches for TRD.

Further evidence for plasma progranulin as a biomarker in bipolar disorder

BACKGROUND

A recent study suggested that progranulin (encoded by the fronto-temporal dementia risk gene GRN) plasma levels are decreased in bipolar disorder (BD). Replication of this finding is however lacking.

METHODS

Progranulin plasma levels of bipolar patients (n=104) and healthy controls (n=80) were measured by enzyme-linked immunosorbent assay (ELISA). Participants were also genotyped for three single nucleotide polymorphisms (SNPs) in the GRN gene (rs2879096, rs4792938 and rs5848), and the effect of genetic variation on progranulin levels was examined.

RESULTS

Plasma progranulin levels were decreased in BD (ANCOVA, p=0.001). Furthermore, age was significantly and positively correlated with plasma progranulin (Pearson׳s correlation, r=0.269, p<0.001). Also, lithium treatment but no other medication had a significant effect on progranulin plasma levels (ANCOVA, p=0.007). Specifically in BD, the GRN SNP rs5848 was associated with progranulin plasma levels (Kruskal-Wallis test, p<0.005).

LIMITATIONS

Subgroup analysis regarding bipolar I vs. bipolar II subtype and polarity of the episode at sampling (manic vs. depressed vs. mixed vs. rapid cycling vs. euthymic) could only be performed with limited validity due to the relatively small sample size. The suitability of peripheral progranulin as a biomarker for BD is limited due to the overlap between patients and controls.

CONCLUSION

The findings strengthen the evidence for progranulin being involved in pathomechanisms of bipolar disorder, and suggest a genetic determinant of progranulin concentrations that is relevant specifically in bipolar patients.

Targeting classical IL-6 signalling or IL-6 trans-signalling in depression?

INTRODUCTION

Increased IL-6 and soluble IL-6 receptor (sIL-6R) levels in depressed patients was first shown over 20 years ago. The pro-inflammatory effects of IL-6 are predominantly mediated by IL-6 trans-signalling via the sIL-6R, whereas IL-6R membrane signalling has anti-inflammatory effects.

AREAS COVERED

We review data on IL-6 and sIL-6R in inflammation, depression, animal models of depression and the effects of different classes of antidepressants. The biological context for IL-6 trans-signalling as a pathogenic factor in depression involves its role in the acute phase response, disorders in zinc and the erythron, hypothalamic-pituitary-adrenal axis activation, induction of the tryptophan catabolite pathway, oxidative stress, bacterial translocation, transition towards sensitisation, autoimmune processes and neuroprogression and the multicausal aetiology of depression, considering that psychosocial stressors and comorbid immune-inflammatory diseases are associated with the onset of depression.

EXPERT OPINION

The homeostatic functions of IL-6 imply that ubiquitous IL-6 inhibitors, for example, tocilizumab, may not be the optimal treatment target in depression. A more promising target may be to increase soluble glycoprotein 130 (sgp130) inhibition of IL-6 trans-signalling, while allowing the maintenance of IL-6R membrane signalling. Future research should delineate the effects of treatments with sgp130Fc in combination with antidepressants in various animal models of chronic depression.

The cytokine model of schizophrenia: emerging therapeutic strategies

We discuss the rationale for a trial of a novel biological immunotherapy in schizophrenia (SCZ). Available antipsychotic treatments for SCZ are often limited by partial effectiveness and significant side effects. The search for novel medications is of high priority. All current antipsychotics function primarily by blocking D2-type dopamine receptors. An emerging theory of SCZ postulates disturbances of cytokines and inflammatory mediators (i.e., the cytokine model), possibly originating in part from infectious exposures. Cytokines are one of the most important components of the immune system that orchestrate the response to infectious and other exogenous insults. Preclinical models of SCZ support a convergence between a role for certain cytokines in the pathophysiology of SCZ and major neurochemical postulates of the disorder, including the dopamine and glutamate hypotheses. Several cytokines are elevated in plasma in SCZ, and positron emission tomography studies have shown active inflammation in the brains of patients with psychosis. Treatment studies of anti-inflammatory agents, such as celecoxib and aspirin, in patients with SCZ have provided further support for neuroinflammation in this disorder. The development of approved biological therapies for autoimmune diseases provides new opportunities to target cytokine signaling directly as a novel treatment strategy in SCZ. In addition, advances in imaging, immunology, and psychopharmacology have paved the way for using measures of target engagement of neuroimmune components that would facilitate the identification of patient subgroups who are most likely to benefit from cytokine modulation.

NLRP3 inflammasome is activated in mononuclear blood cells from patients with major depressive disorder

INTRODUCTION

Major depressive disorder (MDD) is a very prevalent disease which pathogenic mechanism remains elusive. There are some hypotheses and pilot studies suggesting that cytokines may play an important role in MDD. In this respect, we have investigated the role of NLRP3 inflammasome complex in the maturation of caspase-1 and the processing of its substrates, IL-1β and IL-18, in blood cells from MDD patients.

METHODS

Forty MDD patients were selected for this study, twenty without treatments and twenty treated with amitriptyline, a common tricyclic antidepressant. Blood samples from twenty healthy volunteers were included in the study. The inflammasome activation was studied by Western blot and real-time PCR of NLRP3 and caspase 1 and serum levels of IL-1β and 18.

RESULTS

We observed increased gene expression of NLRP3 and caspase-1 in blood cells, and increased serum levels of IL-1β and IL-18 in non-treated patients. IL-1β and IL-18 correlated with Beck Depression Inventory (BDI) scores of MDD patients. Interestingly, amitriptyline treatment reduced NLRP3 and caspase-1 gene expression, and IL-1β and IL-18 serum levels. As it is well established that oxidative stress is associated with NLRP3 inflammasome activation, we next studied mitochondrial ROS and lipid peroxidation (LPO) levels in MDD patients. Increased levels of mitochondrial ROS and LPO were observed in MDD patients, however oxidative damage was higher in MDD patients treated with amitriptyline.

CONCLUSIONS

These findings provide new insight into the pathogenesis of MDD and the effects of amitriptyline treatment on NLRP3 inflammasome activation and IL-1β and IL-18 serum levels.

Antidepressant-like effect of celecoxib piroxicam in rat models of depression

Beyond the current hypothesis of depression, several new biological substrates have been proposed for this disorder. The present study investigated whether the anti-inflammatory drugs celecoxib and piroxicam have antidepressant activity in animal models of depression. After acute administration, we observed antidepressant-like effects of celecoxib (10 mg/kg) and piroxicam (10 mg/kg) in the modified forced swim test in rats. Piroxicam increased serotonin and norepinephrine levels in the hippocampus. Prolonged (21-day) treatment with celecoxib (10 mg/kg) and piroxicam (10 mg/kg) rescued sucrose preference in a chronic mild stress model of depression. Additionally, the chronic mild stress-induced reduction of hippocampal glutathione was prevented by treatment with celecoxib and piroxicam. Superoxide dismutase in the hippocampus was increased after chronic mild stress compared with the non-stressed saline group. The non-stressed celecoxib and piroxicam groups and stressed piroxicam group exhibited an increase in hippocampal superoxide dismutase activity compared with the stressed saline group. Lipid hydroperoxide was increased in the stressed group treated with vehicle and non-stressed group treated with imipramine but not in the stressed groups treated with celecoxib and piroxicam. These results suggest that the antidepressant-like effects of anti-inflammatory drugs might be attributable to enhanced antioxidant defenses and attenuated oxidative stress in the hippocampus.

Efficacy of adjunctive celecoxib treatment for patients with major depressive disorder: a meta-analysis

BACKGROUND

Numerous studies have reported that inflammation is closely associated with depression, and adjunctive non-steroidal anti-inflammatory drug (NSAID) treatment has been suggested as a novel therapeutic approach for depression.

METHODS

We searched electronic databases including Medline, Embase, and the Cochrane Central Register of Controlled Trials. We only included randomized controlled trials comparing adjunctive NSAIDs with placebos for treating depressive episodes.

RESULTS

Of the 654 retrieved entries, we identified four relevant studies with a total of 150 patients (75 NSAID patients and 75 placebo patients) with depressive episodes. All four studies used celecoxib as the NSAID. The patients receiving adjunctive celecoxib had significantly higher mean changes in the Hamilton Rating Scale for Depression scores between baseline and endpoint measurements compared with those receiving placebo (weighted mean difference=3.26, 95% confidence interval; CI=1.81 to 4.71). The adjunctive celecoxib group also showed better remission (odds ratio; OR=6.58, 95% CI=2.55 to 17.00) and response rates (OR=6.49, 95% CI=2.89 to 14.55) than the placebo group. The all-cause drop-out rate was more favorable for the celecoxib group than for the placebo group (OR=0.45, 95% CI=0.18 to 1.13), although the statistical significance was not statistically significant (p=0.09).

CONCLUSION

Adjunctive treatment with NSAIDs, particularly celecoxib, can be a promising strategy for patients with depressive disorder. Future studies with a larger sample size and longer study duration are needed to confirm the efficacy and tolerability of NSAIDs for depression.

Immunology of major depression

High levels of several proinflammatory components of the immune system, such as interleukin-6, C-reactive protein, tumor necrosis factor (TNF)-α, or neopterin in patients suffering from major depression (MD) point to the involvement of an inflammatory process in the pathophysiology of MD. The direct and indirect effects of cytokines on neurotransmitter storage and release - mediated by microglia cells and astrocytes - are discussed. The tryptophan/kynurenine metabolism is one of the indirect mechanisms because the enzyme indoleamine 2,3-dioxygenase - a key enzyme of this metabolism in the central nervous system - is driven by pro- and anti-inflammatory cytokines and degrades serotonin. Moreover, neuroactive kynurenines such as kynurenic acid and quinolinic acid act on the glutamatergic neurotransmission as N-methyl-D-aspartate antagonists and agonists, respectively. Alterations of the serotonergic, noradrenergic and glutamatergic neurotransmission have been shown with low-level neuroinflammation and may be involved in symptom generation. Epidemiological and clinical studies show a role for inflammation as a risk factor for MD. A large-scale epidemiological study in MD clearly demonstrates that severe infections and autoimmune disorders are lifetime risk factors for MD. The vulnerability-stress-inflammation model matches with this view as stress may increase proinflammatory cytokines and even contribute to a lasting proinflammatory state. Further support comes from the therapeutic benefit of anti-inflammatory medications such as the cyclo-oxygenase-2 inhibitors, TNF-α antagonists and others, and the anti-inflammatory and immunomodulatory intrinsic effects of antidepressants.

Mind and body: how the health of the body impacts on neuropsychiatry

It has long been established in traditional forms of medicine and in anecdotal knowledge that the health of the body and the mind are inextricably linked. Strong and continually developing evidence now suggests a link between disorders which involve Hypothalamic-Pituitary-Adrenal axis (HPA) dysregulation and the risk of developing psychiatric disease. For instance, adverse or excessive responses to stressful experiences are built into the diagnostic criteria for several psychiatric disorders, including depression and anxiety disorders. Interestingly, peripheral disorders such as metabolic disorders and cardiovascular diseases are also associated with HPA changes. Furthermore, many other systemic disorders associated with a higher incidence of psychiatric disease involve a significant inflammatory component. In fact, inflammatory and endocrine pathways seem to interact in both the periphery and the central nervous system (CNS) to potentiate states of psychiatric dysfunction. This review synthesizes clinical and animal data looking at interactions between peripheral and central factors, developing an understanding at the molecular and cellular level of how processes in the entire body can impact on mental state and psychiatric health.

Cytokines as biomarkers in depressive disorder: current standing and prospects

The frequently observed co-occurrence of depressive disorders and inflammatory diseases suggests a close connection between the nervous and the immune systems. Increased pro-inflammatory and type 1 cytokines, such as interleukin (IL)-1, tumour necrosis factor (TNF)-α and interferon (IFN)-γ, appear to be an important link. Cytokines are synthesized by immune cells in the blood and peripheral tissues and by glial cells in the central nervous system (CNS). Evidence suggests that the blood-brain barrier (BBB) is permeable to cytokines and immune cells, and that afferent nerves, e.g. the vagus nerve, mediate the communication between peripheral inflammatory processes and CNS. Cytokines such as IL-1ß, TNF-α and IFN-γ seem to contribute to the pathophysiology of depression by activating monoamine reuptake, stimulating the hypothalamic-pituitary-adrenocortical (HPA) axis and decreasing production of serotonin due to increased activity of indolamine-2,3-dioxygenase (IDO). However, critical appraisal of these hypotheses is required, because cytokine elevation is not specific to depression. Moreover, several effective antidepressants such as amitriptyline and mirtazapine have been shown to increase cytokine production. When applying immunomodulatory therapies, these drugs may increase the risk of specific side effects such as infections or interact with antidepressant drugs on important functions of the body such as the coagulation system.

Effects of doxycycline on depressive-like behavior in mice after lipopolysaccharide (LPS) administration

Current evidences support inflammation, oxidative and nitrogen stress, as well as brain-derived neurotrophic factor (BDNF) signaling mechanisms as important in depression pathophysiology. Tetracycline antibiotics have anti-inflammatory and antioxidant properties. Preliminary evidence indicates that minocycline has antidepressant properties. Doxycycline (DOXY) has favorable pharmacokinetic and safety profiles when compared to other tetracycline congeners. The antidepressant activity of DOXY has not been adequately investigated. This study evaluated the effects of DOXY (25 and 50 mg/kg, i.p.) on LPS-induced (0.5 mg/kg, i.p.) depressive-like behavior. Doxycycline was administered 30 min before LPS (pre-LPS) or 1.5 and 23.5 h following LPS (post-LPS) administration in mice. LPS-treated animals presented an increase in immobility time in the forced swimming test (FST) when compared to controls 24 h after endotoxin administration. Similarly to imipramine (IMI-10 mg/kg, i.p.), DOXY at both doses prevented and reversed LPS-induced alterations in the FST. IL-1β content was increased 24 h after LPS administration in striatum, hippocampus and prefrontal cortex. IMI and DOXY prevented and reversed LPS-induced increase in IL-1β. IMI and DOXY also prevented and reversed LPS-induced alterations in nitrite content and oxidative stress parameters (lipid peroxidation and reduced glutathione levels). Both DOXY and IMI prevented LPS-induced decrease in hippocampal BDNF levels. Taken together, our results demonstrate that DOXY is comparable to IMI in effectively ameliorate LPS-induced depressive-like behavior, providing a rationale for testing DOXY's antidepressant efficacy in humans.

Synergistic effects of celecoxib and bupropion in a model of chronic inflammation-related depression in mice

This study was aimed to characterize the depression-like behaviour in the classical model of chronic inflammation induced by Complete Freund's Adjuvant (CFA). Male Swiss mice received an intraplantar (i.pl.) injection of CFA (50 µl/paw) or vehicle. Behavioural and inflammatory responses were measured at different time-points (1 to 4 weeks), and different pharmacological tools were tested. The brain levels of IL-1β and BDNF, or COX-2 expression were also determined. CFA elicited a time-dependent edema formation and mechanical allodynia, which was accompanied by a significant increase in the immobility time in the tail suspension (TST) or forced-swimming (FST) depression tests. Repeated administration of the antidepressants imipramine (10 mg/kg), fluoxetine (20 mg/kg) and bupropion (30 mg/kg) significantly reversed depression-like behaviour induced by CFA. Predictably, the anti-inflammatory drugs dexamethasone (0.5 mg/kg), indomethacin (10 mg/kg) and celecoxib (30 mg/kg) markedly reduced CFA-induced edema. The oral treatment with the analgesic drugs dipyrone (30 and 300 mg/kg) or pregabalin (30 mg/kg) significantly reversed the mechanical allodyinia induced by CFA. Otherwise, either dipyrone or pregabalin (both 30 mg/kg) did not significantly affect the paw edema or the depressive-like behaviour induced by CFA, whereas the oral treatment with dipyrone (300 mg/kg) was able to reduce the immobility time in TST. Noteworthy, CFA-induced edema was reduced by bupropion (30 mg/kg), and depression behaviour was prevented by celecoxib (30 mg/kg). The co-treatment with bupropion and celecoxib (3 mg/kg each) significantly inhibited both inflammation and depression elicited by CFA. The same combined treatment reduced the brain levels of IL-1β, as well as COX-2 immunopositivity, whilst it failed to affect the reduction of BDNF levels. We provide novel evidence on the relationship between chronic inflammation and depression, suggesting that combination of antidepressant and anti-inflammatory agents bupropion and celecoxib might represent an attractive therapeutic strategy for depression.

Sleep architecture variation: a mediator of metabolic disturbance in individuals with major depressive disorder

Remarkable proportions of individuals diagnosed with major depressive disorder (MDD) have comorbid metabolic disturbances (i.e., obesity, type 2 diabetes mellitus (T2DM), hypertension, dyslipidemia), and vice versa. Accumulating evidence suggests that common pathophysiologic pathways such as a chronic, low-grade, proinflammatory state mediate this frequent co-occurrence. However, it remains unclear what traits precede the onset and increase the risk for these pathologic states. The aim of our review was to evaluate the evidentiary base supporting the hypothesis that the increased hazard for metabolic disturbance in MDD subpopulations (and vice versa) is mediated in part by endophenotypic variations in sleep architecture. We conducted a PubMed search of all English-language literature with the following search terms: sleep disturbance, circadian rhythm, inflammation, metabolic syndrome, obesity, MDD, mood disorder, prodrome, T2DM, cytokine, interleukin, hypertension, dyslipidemia, and hypercholesterolemia. Longitudinal and meta-analysis data indicate that specific variations in sleep architecture (i.e., decreased slow-wave sleep [SWS], increased rapid eye movement [REM] density) precede the onset of depressive symptomatology for a subpopulation of individuals. The same sleep architecture variations also are associated with obesity, T2DM, and hypertension. Decreased SWS and increased REM density is correlated with an increase in proinflammatory cytokines (e.g., IL-6, tumor necrosis factor, etc.). This proinflammatory state has been independently shown to be associated with MDD and metabolic disturbances. Taken together, our review suggests that sleep architecture variation of increased REM density and decreased SWS may be an endophenotypic trait, which serves to identify a subpopulation at increased risk for depressive symptoms and metabolic disturbances. Future research is needed to discern the predictive value, sensitivity, and specificity of using sleep architecture variation as a biomarker for MDD and metabolic disturbances. Validation of this marker would have broad clinical implications, such as primary, secondary, and tertiary preventative health strategies.

Research review: the role of cytokines in depression in adolescents: a systematic review

BACKGROUND

While cytokines have been implicated in the pathophysiology of depression in adults, the potential role in younger age groups such as adolescents is less clear. This article therefore reviews the literature (a) to explore the relationship between cytokines and depression in adolescents, and (b) to examine how cytokines may be related to adolescent depression in the context of other neurobiological theories of depression.

METHOD

A systematic review of the scientific literature on the subject was conducted in February 2013, searching the Web of Knowledge, PubMed (Medline), PsycInfo and Cochrane electronic databases.

RESULTS

Eighteen studies were identified measuring both depression or depressive symptoms and cytokines or immune markers in adolescents. Adolescents with depression show age-specific characteristics of the immune and inflammatory system, specifically in NK cell activity and in pro-inflammatory cytokines (such as IL-1β and TNF-α). In addition, the role of cytokines in adolescent depression is influenced by neurodevelopment, hormonal changes, stress and trauma.

CONCLUSIONS

There may be differences in the neurobiology of adolescent major depressive disorder (MDD) compared with adult MDD. Increased understanding of the role of cytokines in adolescent MDD may lead to improved outcomes in the treatment of adolescent depression.

Cytokine alterations in bipolar disorder: a meta-analysis of 30 studies

BACKGROUND

We conducted a meta-analysis of studies comparing cytokine concentrations between patients with bipolar disorder (BD) and healthy control subjects (HCs).

METHODS

We searched ISI Web of Science, MEDLINE, BIOSIS Previews, Scopus, Current Contents Connect, and Biological Abstracts for relevant studies. Based on heterogeneity status, we used fixed-effect or restricted maximal likelihood model to perform meta-analysis.

RESULTS

Thirty studies with a total of 2599 participants (1351 BD and 1248 HCs) were eligible for the analysis. Concentrations of interleukin (IL)-4 (p = .008), IL-6 (p = .073), IL-10 (p = .013), soluble IL-2 receptor (sIL-2R; p < .001), sIL-6R (p = .021), tumor necrosis factor (TNF)-α (p = .010), soluble TNF receptor-1 (sTNFR1; p < .001), and IL-1 receptor antagonist (p value in mania < .001 and euthymia = .021) were significantly elevated in patients compared with HCs. Moreover, IL-1β (p = .059), and IL-6 (p = .073) tended to show higher values in patients. Levels of IL-2 (p = .156), interferon (INF)-γ (p = .741), C-C motif ligand 2 (p = .624), and IL-8 (p = .952) did not significantly differ between patients and HCs. Subgroup analysis based on mitogen stimulation status partially or completely resolved heterogeneity for most of the cytokines. Concentrations of IL-2, IL-4, sIL-6R, and INF-γ were unrelated to medication status. Phasic difference was present for TNF-α, sTNFR1, sIL-2R, IL-6, and IL-1RA, whereas it was absent for IL-4 and IL-10.

CONCLUSIONS

This meta-analysis provides evidence for significant elevation of proinflammatory, anti-inflammatory, and regulatory cytokines in BD.

Dysregulated relationship of inflammation and oxidative stress in major depression

Chronic inflammation and oxidative stress have been implicated in the pathophysiology of Major Depressive Disorder (MDD), as well as in a number of chronic medical conditions. The aim of this study was to examine the relationship between peripheral inflammatory and oxidative stress markers in un-medicated subjects with MDD compared to non-depressed healthy controls and compared to subjects with MDD after antidepressant treatment. We examined the relationships between IL-6, IL-10, and the IL-6/IL-10 inflammatory ratio vs. F2-isoprostanes (F2-IsoP), a marker of oxidative stress, in un-medicated MDD patients (n=20) before and after 8 weeks of open-label sertraline treatment (n=17), compared to healthy non-depressed controls (n=20). Among the un-medicated MDD subjects, F2-IsoP concentrations were positively correlated with IL-6 concentrations (p<0.05) and were negatively correlated with IL-10 concentrations (p<0.01). Accordingly, F2-IsoP concentrations were positively correlated with the ratio of IL-6/IL-10 (p<0.01). In contrast, in the control group, there were no significant correlations between F2-IsoPs and either cytokine or their ratio. After MDD subjects were treated with sertraline for 8 weeks, F2-IsoPs were no longer significantly correlated with IL-6, IL-10 or the IL-6/IL-10 ratio. These data suggest oxidative stress and inflammatory processes are positively associated in untreated MDD. Our findings are consistent with the hypothesis that the homeostatic buffering mechanisms regulating oxidation and inflammation in healthy individuals become dysregulated in untreated MDD, and may be improved with antidepressant treatment. These findings may help explain the increased risk of comorbid medical illnesses in MDD.

Does pioglitazone improve depression through insulin-sensitization? Results of a randomized double-blind metformin-controlled trial in patients with polycystic ovarian syndrome and comorbid depression

Thiazolidinediones have shown beneficial effects in short-term treatment of depression. However, it is unclear whether the antidepressant efficacy of these agents is related to their insulin-sensitizing action. We conducted the present study to compare the antidepressant efficacy of pioglitazone with another insulin-sensitizer, metformin, in obese patients with concomitant polycystic ovarian syndrome (PCOS) and major depressive disorder (MDD). In a six-week double-blind study, 50 patients with PCOS and MDD (DSM-IV-TR criteria) with Hamilton depression rating scale (HDRS) score of <20, randomly received pioglitazone (15 mg twice daily; PO) or metformin (750 mg twice daily; PO). Assessment was done using HDRS (weeks 0, 3, 6) together with fasting Insulin, glucose, and lipid profile, liver enzymes, homeostatic model assessment of insulin resistance (HOMA-IR), anthropometric measures, and serum androgens (weeks 0 and 6). Pioglitazone was superior to metformin in reducing HDRS scores at the end of the study [38.3% versus 8.3% reduction from baseline scores, F(1, 37) = 73.513, P<0.001]. Changes from baseline in HOMA-IR values at week 6 were not significantly different between the two groups (P = 0.888). Baseline (but not follow-up) HDRS and HOMA-IR values were significantly correlated (r = 0.393, P = 0.012). In multiple regression analysis, treatment with pioglitazone independent of HOMA-IR values predicted greater score reduction on HDRS at week 6 (standardized beta = 0.801, P<0.001). Biochemical and hormonal profile did not differ between the two groups at week 6. Metformin was associated with higher frequency of gastrointestinal side effects (P = 0.014). In summary, we showed that pioglitazone improved depression with mechanisms largely unrelated to its insulin-sensitizing action (registration number: IRCT201106081556N23).

Evidence for a dysregulated immune system in the etiology of psychiatric disorders

There is extensive bi-directional communication between the brain and the immune system in both health and disease. In recent years, the role of an altered immune system in the etiology of major psychiatric disorders has become more apparent. Studies have demonstrated that some patients with major psychiatric disorders exhibit characteristic signs of immune dysregulation and that this may be a common pathophysiological mechanism that underlies the development and progression of these disorders. Furthermore, many psychiatric disorders are also often accompanied by chronic medical conditions related to immune dysfunction such as autoimmune diseases, diabetes and atherosclerosis. One of the major psychiatric disorders that has been associated with an altered immune system is schizophrenia, with approximately one third of patients with this disorder showing immunological abnormalities such as an altered cytokine profile in serum and cerebrospinal fluid. An altered cytokine profile is also found in a proportion of patients with major depressive disorder and is thought to be potentially related to the pathophysiology of this disorder. Emerging evidence suggests that altered immune parameters may also be implicated in the neurobiological etiology of autism spectrum disorders. Further support for a role of immune dysregulation in the pathophysiology of these psychiatric disorders comes from studies showing the immunomodulating effects of antipsychotics and antidepressants, and the mood altering effects of anti-inflammatory therapies. This review will not attempt to discuss all of the psychiatric disorders that have been associated with an augmented immune system, but will instead focus on several key disorders where dysregulation of this system has been implicated in their pathophysiology including depression, schizophrenia and autism spectrum disorder.

Aspirin: a review of its neurobiological properties and therapeutic potential for mental illness

There is compelling evidence to support an aetiological role for inflammation, oxidative and nitrosative stress (O&NS), and mitochondrial dysfunction in the pathophysiology of major neuropsychiatric disorders, including depression, schizophrenia, bipolar disorder, and Alzheimer's disease (AD). These may represent new pathways for therapy. Aspirin is a non-steroidal anti-inflammatory drug that is an irreversible inhibitor of both cyclooxygenase (COX)-1 and COX-2, It stimulates endogenous production of anti-inflammatory regulatory 'braking signals', including lipoxins, which dampen the inflammatory response and reduce levels of inflammatory biomarkers, including C-reactive protein, tumor necrosis factor-α and interleukin (IL)--6, but not negative immunoregulatory cytokines, such as IL-4 and IL-10. Aspirin can reduce oxidative stress and protect against oxidative damage. Early evidence suggests there are beneficial effects of aspirin in preclinical and clinical studies in mood disorders and schizophrenia, and epidemiological data suggests that high-dose aspirin is associated with a reduced risk of AD. Aspirin, one of the oldest agents in medicine, is a potential new therapy for a range of neuropsychiatric disorders, and may provide proof-of-principle support for the role of inflammation and O&NS in the pathophysiology of this diverse group of disorders.

Celecoxib as adjunctive treatment to risperidone in children with autistic disorder: a randomized, double-blind, placebo-controlled trial

RATIONAL

Autism is associated with activation of the inflammatory response system.

OBJECTIVE

This study aims to assess the efficacy of a cyclooxygenase-2 inhibitor, celecoxib, as adjunctive therapy in the treatment of autism

METHODS

In a 10-week randomized double-blind placebo-controlled study, 40 outpatient children with a Diagnostic and Statistical Manual of Mental Disorders, fourth edition, text revision clinical diagnosis of autism were randomly allocated to celecoxib plus risperidone or placebo plus risperidone. The dose of risperidone and celecoxib were titrated up to 3 and 300 mg/day, respectively. Patients were assessed at baseline and after 2, 4, 6, and 10 weeks of starting medication using the Aberrant Behavior Checklist-Community (ABC-C) Rating Scale. Primary outcome measure was the change in irritability subscale of ABC-C.

RESULTS

Significant time × treatment interaction was observed for Irritability (F (1.658, 63.021) = 13.580, P < 0.001), Lethargy/Social Withdrawal (F (1.948, 74.032) = 16.811, P < 0.001), and Stereotypic Behavior (F(1.742, 66.198) = 12.104, P < 0.001), but not for Hyperactivity/Noncompliance (F (2.564, 97.424) = 1.469, P = 0.232), and Inappropriate Speech subscales (F (1.607, 61.075) = 0.173, P = 0.794). By week 10, patients in the celecoxib group showed significantly greater improvement in the Irritability (P < 0.001), Lethargy/Social Withdrawal (P < 0.001), and Stereotypic Behavior (P < 0.00) but not in Hyperactivity/Noncompliance (P = 0.202) and Inappropriate Speech (P = 0.802) subscales than the placebo group. Complete response was achieved by four (20 %) patients in the placebo group and 11 (55 %) patients in the celecoxib group (χ (2) (1) = 5.227, P = 0.022). Frequency of side effects was similar between the two groups.

CONCLUSIONS

Combination of risperidone and celecoxib was superior to risperidone alone in treating irritability, social withdrawal, and stereotypy of children with autism. (Registration, www.irct.ir ; IRCT138711091556N2).

Effects of antidepressants on alternations in serum cytokines and depressive-like behavior in mice after lipopolysaccharide administration

Accumulating evidence suggests that inflammation may play a role in the pathophysiology of major depressive disorder (MDD). Antidepressants, including selective serotonin reuptake inhibitors (SSRIs) and serotonin and norepinephrine reuptake inhibitors (SNRIs), possess anti-inflammatory effects in vitro. Here, we examined the effects of SSRIs and SNRIs on lipopolysaccharide (LPS)-induced inflammation and depressive-like behavior in male mice. A single administration of LPS (0.5mg/kg, i.p.) increased serum levels of the pro-inflammatory cytokine, tumor necrosis factor-α (TNFα) and the anti-inflammatory cytokine, interleukin-10 (IL-10) in mice. Pretreatment with SSRIs (fluoxetine and paroxetine), SNRIs (venlafaxine and duloxetine), or 5-hydroxytryptophan (5-HTP), a precursor of serotonin, attenuated LPS-induced increases in TNFα, whereas it increased serum levels of IL-10, in mice treated with LPS. In the tail suspension test (TST), LPS increased the immobility time without affecting spontaneous locomotor activity, suggesting that LPS induced depressive-like behavior in mice. Treatment with fluoxetine (30 mg/kg) or paroxetine (10mg/kg) significantly shortened LPS-induced increases of immobility time. These results suggested that antidepressants exert anti-inflammatory effects in vivo, and that the serotonergic system may partially mediate these effects. In addition, the anti-inflammatory effects of antidepressants may help alleviate the symptoms of LPS-induced depression in mice.

Multiple antidepressant potential modes of action of curcumin: a review of its anti-inflammatory, monoaminergic, antioxidant, immune-modulating and neuroprotective effects

Curcumin is the principal curcuminoid of the popular Indian spice turmeric and has attracted increasing attention for the treatment of a range of conditions. Research into its potential as a treatment for depression is still in its infancy, although several potential antidepressant mechanisms of action have been identified. Research completed to date on the multiple effects of curcumin is reviewed in this paper, with a specific emphasis on the biological systems that are compromised in depression. The antidepressant effects of curcumin in animal models of depression are summarised, and its influence on neurotransmitters such as serotonin and dopamine is detailed. The effects of curcumin in moderating hypothalamus-pituitary-adrenal disturbances, lowering inflammation and protecting against oxidative stress, mitochondrial damage, neuroprogression and intestinal hyperpermeability, all of which are compromised in major depressive disorder, are also summarised. With increasing interest in natural treatments for depression, and efforts to enhance current treatment outcomes, curcumin is presented as a promising novel, adjunctive or stand-alone natural antidepressant.

Effects of inhibitor of κB kinase activity in the nucleus accumbens on emotional behavior

Inhibitor of κB kinase (IκK) has historically been studied in the context of immune response and inflammation, but recent evidence demonstrates that IκK activity is necessary and sufficient for regulation of neuronal function. Chronic social defeat stress of mice increases IκK activity in the nucleus accumbens (NAc) and this increase is strongly correlated to depression-like behaviors. Inhibition of IκK signaling results in a reversal of chronic social defeat stress-induced social avoidance behavior. Here, we more completely define the role of IκK in anxiety and depressive-like behaviors. Mice underwent stereotaxic microinjection of a herpes simplex virus expressing either green fluorescent protein, a constitutively active form of IκK (IκKca), or a dominant negative form of IκK into the NAc. Of all three experimental groups, only mice expressing IκKca show a behavioral phenotype. Expression of IκKca results in a decrease in the time spent in the non-periphery zones of an open field arena and increased time spent immobile during a forced swim test. No baseline differences in sucrose preference were observed, but following the acute swim stress we noted a marked reduction in sucrose preference. To determine whether IκK activity alters responses to other acute stressors, we examined behavior and spine morphology in mice undergoing an acute social defeat stress. We found that IκKca enhanced social avoidance behavior and promoted thin spine formation. These data show that IκK in NAc is a critical regulator of both depressive- and anxiety-like states and may do so by promoting the formation of immature excitatory synapses.

The genetics of selective serotonin reuptake inhibitors

Selective serotonin reuptake inhibitors (SSRIs) are among the most widely prescribed drugs in psychiatry. Based on the fact that SSRIs increase extracellular monoamine levels in the brain, the monoamine hypothesis of depression was introduced, postulating that depression is associated with too low serotonin, dopamine and noradrenaline levels. However, several lines of evidence indicate that this hypothesis is too simplistic and that depression and the efficacy of SSRIs are dependent on neuroplastic changes mediated by changes in gene expression. Because a coherent view on global gene expression is lacking, we aim to provide an overview of the effects of SSRI treatment on the final targets of 5-HT receptor signal transduction pathways, namely the transcriptional regulation of genes. We address gene polymorphisms in humans that affect SSRI efficacy, as well as in vitro studies employing human-derived cells. We also discuss the molecular targets affected by SSRIs in animal models, both in vivo and in vitro. We conclude that serotonin transporter gene variation in humans affects the efficacy and side-effects of SSRIs, whereas SSRIs generally do not affect serotonin transporter gene expression in animals. Instead, SSRIs alter mRNA levels of genes encoding serotonin receptors, components of non-serotonergic neurotransmitter systems, neurotrophic factors, hypothalamic hormones and inflammatory factors. So far little is known about the epigenetic and age-dependent molecular effects of SSRIs, which might give more insights in the working mechanism(s) of SSRIs.