Impact of lithium alone and in combination with antidepressants on cytokine production in vitro

Abelson Helper Integration Site 1 haplotypes and peripheral blood expression associates with lithium response and immunomodulation in bipolar patients

RATIONALE

In bipolar disorder (BD), immunological factors play a role in the pathogenesis and treatment of the illness. Studies showed the potential link between Abelson Helper Integration Site 1 (AHI1) protein, behavioural changes and innate immunity regulation. An immunomodulatory effect was suggested for lithium, a mood stabilizer used in BD treatment.

OBJECTIVES

We hypothesized that AHI1 may be an important mediator of lithium treatment response. Our study aimed to investigate whether the AHI1 haplotypes and expression associates with lithium treatment response in BD patients. We also examined whether AHI1 expression and lithium treatment correlate with innate inflammatory response genes.

RESULTS

We genotyped seven AHI1 single nucleotide polymorphisms in 97 euthymic BD patients and found that TG haplotype (rs7739635, rs9494332) was significantly associated with lithium response. We also showed significantly increased AHI1 expression in the blood of lithium responders compared to non-responders and BD patients compared to healthy controls (HC). We analyzed the expression of genes involved in the innate immune response and inflammatory response regulation (TLR4, CASP4, CASP5, NLRP3, IL1A, IL1B, IL6, IL10, IL18) in 21 lithium-treated BD patients, 20 BD patients treated with other mood stabilizer and 19 HC. We found significantly altered expression between BD patients and HC, but not between BD patients treated with different mood stabilizers.

CONCLUSIONS

Our study suggests the involvement of AHI1 in the lithium mode of action. Moreover, mood-stabilizing treatment associated with the innate immunity-related gene expression in BD patients and only the lithium-treated BD patients showed significantly elevated expression of anti-inflammatory IL10, suggesting lithium's immunomodulatory potential.

Accumulation and neuroprotective effects of lithium on hepatocellular carcinoma mice model

AIM

The peripheral tumor growth is accompanied by the accumulation of inflammatory mediators in the blood that can negatively influence blood-brain barrier function and neuronal structure and develop the cancer-associated depression. The aim of the study was to evaluate the neurobiological effects of lithium on hepatocellular carcinoma mice model.

METHODS

In this study we analyzed the locomotor activity of lithium-treated tumor-bearing mice using the Phenomaster instrument. Inductively coupled plasma mass-spectral analysis was used to determine lithium levels in blood, brain, liver, kidneys, tumors and muscle tissues. The prefrontal cortex neurons ultrastructure was assessed by transmission electron microscopy. Expression of BDNF, GRP78, EEA1, LAMP1, and LC3 beta in neurons was determined by immunohistochemical analysis.

RESULTS

A decrease in locomotor activity was found in animals with tumors. At the same time, the low expression levels of the neurotrophic factor BDNF and early endosomal marker EEA1 were revealed, as well as the decreased amount of synaptic vesicles and synapses was shown. Signs of endoplasmic reticulum stress and autophagy development in neurons of animals with tumors were noted. Lithium carbonate administration had a corrective effect on animal's behavior and the prefrontal cortex neurons structure.

CONCLUSIONS

In summary, lithium can restore the neuronal homeostasis in tumor-bearing mice.

Folic acid supplementation improved cognitive deficits associated with lithium administration during pregnancy in rat offspring

INTRODUCTION

The present study aimed to analyse both neurobehavioural and biochemical results of neonates born of mothers exposed to different doses of lithium along with the groups that received lithium at the highest dose with folic acid as a preventive treatment.

MATERIALS AND METHODS

Male and female rats were mated in separate cages, and pregnant rats were divided into eight first group as (1) vehicle; (2) propylthiouracil (PTU)-induced hypothyroidism; (3-4) received two different doses of lithium carbonate (15 and 30 mg/kg); (5-7) the highest doses of lithium (30 mg/kg) plus three different doses of folic acid (5, 10 and 15 mg/kg); and (8) received just folic acid (15 mg/kg). All treatments were dissolved in drinking water and continued until delivery, followed by returning to a regular diet without treatment.

RESULTS

Lithium (30 mg/kg) disrupts both behavioural and biochemical markers, including TSH, T3 and T4 as measuring indicators to assess thyroid function, IL-10 and TNF-α as anti-inflammatory and inflammatory agents, respectively, malondialdehyde as an oxidative stress marker, alongside SOD, and catalase activity as antioxidant indicators. Besides, folic acid, almost at the highest dose (15 mg/kg), attenuated memory impairement and anxiety-like behaviour caused by lithium. Moreover, the groups treated with folic acid alone in comparison with vehicles demonstrated higher levels of antioxidant and anti-inflammatory indicators.

CONCLUSION

According to the results, prenatal exposure to a high dose of lithium (30 mg/kg) leads to foetal neurodevelopmental disorder and growth restriction through various mechanisms more likely attributed to hypothyroidism, which means it should be either prohibited or prescribed cautiously during pregnancy.

Transcriptional and functional effects of lithium in bipolar disorder iPSC-derived cortical spheroids

Lithium (Li) is recommended for long-term treatment of bipolar disorder (BD). However, its mechanism of action is still poorly understood. Induced pluripotent stem cell (iPSC)-derived brain organoids have emerged as a powerful tool for modeling BD-related disease mechanisms. We studied the effects of 1 mM Li treatment for 1 month in iPSC-derived human cortical spheroids (hCS) from 10 healthy controls (CTRL) and 11 BD patients (6 Li-responders, Li-R, and 5 Li non-treated, Li-N). At day 180 of differentiation, BD hCS showed smaller size, reduced proportion of neurons, decreased neuronal excitability and reduced neural network activity compared to CTRL hCS. Li rescued excitability of BD hCS neurons by exerting an opposite effect in the two diagnostic groups, increasing excitability in BD hCS and decreasing it in CTRL hCS. We identified 132 Li-associated differentially expressed genes (DEGs), which were overrepresented in sodium ion homeostasis and kidney-related pathways. Moreover, Li regulated secretion of pro-inflammatory cytokines and increased mitochondrial reserve capacity in BD hCS. Through long-term Li treatment of a human 3D brain model, this study partly elucidates the functional and transcriptional mechanisms underlying the clinical effects of Li, such as rescue of neuronal excitability and neuroprotection. Our results also underscore the substantial influence of treatment duration in Li studies. Lastly, this study illustrates the potential of patient iPSC-derived 3D brain models for precision medicine in psychiatry.

Lithium in Cancer Therapy: Friend or Foe?

Lithium, a trace element important for fetal health and development, is considered a metal drug with a well-established clinical regime, economical production process, and a mature storage system. Several studies have shown that lithium affects tumor development by regulating inositol monophosphate (IMPase) and glycogen synthase kinase-3 (GSK-3). Lithium can also promote proliferation and programmed cell death (PCD) in tumor cells through a number of new targets, such as the nuclear receptor NR4A1 and Hedgehog-Gli. Lithium may increase cancer treatment efficacy while reducing side effects, suggesting that it can be used as an adjunctive therapy. In this review, we summarize the effects of lithium on tumor progression and discuss the underlying mechanisms. Additionally, we discuss lithium's limitations in antitumor clinical applications, including its narrow therapeutic window and potential pro-cancer effects on the tumor immune system.

Genome-Wide Association Study of Lithium-Induced Dry Mouth in Bipolar I Disorder

Dry mouth is a rather common unpleasant adverse drug reaction (ADR) to lithium treatment in bipolar disorders that often lead to poor adherence or early dropout. The aim of this study was to identify the genetic variants of dry mouth associated with lithium treatment in patients with bipolar I (BPI) disorder. In total, 1242 BPI patients who had ever received lithium treatment were identified by the Taiwan Bipolar Consortium for this study. The proportions of patients who experienced impaired drug compliance during lithium medication were comparable between those only with dry mouth and those with any other ADR (86% and 93%, respectively). Dry mouth appeared to be the most prevalent (47.3%) ADR induced by lithium treatment. From the study patients, 921 were included in a genome-wide association study (GWAS), and replication was conducted in the remaining 321 patients. The SNP rs10135918, located in the immunoglobulin heavy chain locus (IGH), showed the strongest associations in the GWAS (p = 2.12 × 10⁻³⁷) and replication groups (p = 6.36 × 10⁻¹³) (dominant model) for dry mouth with a sensitivity of 84.9% in predicting dry mouth induced by lithium. Our results may be translated into clinical recommendation to help identify at-risk individuals for early identification and management of dry mouth, which will improve medication adherence.

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.

COVID-19 vaccination for people with severe mental illness: why, what, and how?

Psychiatric disorders, and especially severe mental illness, are associated with an increased risk of severe acute respiratory syndrome coronavirus 2 infection and COVID-19-related morbidity and mortality. People with severe mental illness should therefore be prioritised in vaccine allocation strategies. Here, we discuss the risk for worse COVID-19 outcomes in this vulnerable group, the effect of severe mental illness and psychotropic medications on vaccination response, the attitudes of people with severe mental illness towards vaccination, and, the potential barriers to, and possible solutions for, an efficient vaccination programme in this population.

The neuropsychiatric manifestations of COVID-19: Interactions with psychiatric illness and pharmacological treatment

The recent outbreak of the corona virus disease (COVID-19) has had major global impact. The relationship between severe acute respiratory syndrome coronavirus (SARS-CoV-2) infection and psychiatric diseases is of great concern, with an evident link between corona virus infections and various central and peripheral nervous system manifestations. Unmitigated neuro-inflammation has been noted to underlie not only the severe respiratory complications of the disease but is also present in a range of neuro-psychiatric illnesses. Several neurological and psychiatric disorders are characterized by immune-inflammatory states, while treatments for these disorders have distinct anti-inflammatory properties and effects. With inflammation being a common contributing factor in SARS-CoV-2, as well as psychiatric disorders, treatment of either condition may affect disease progression of the other or alter response to pharmacological treatment. In this review, we elucidate how viral infections could affect pre-existing psychiatric conditions and how pharmacological treatments of these conditions may affect overall progress and outcome in the treatment of SARS-CoV-2. We address whether any treatment-induced benefits and potential adverse effects may ultimately affect the overall treatment approach, considering the underlying dysregulated neuro-inflammatory processes and potential drug interactions. Finally, we suggest adjunctive treatment options for SARS-CoV-2-associated neuro-psychiatric symptoms.

Inflammation-Related Changes in Mood Disorders and the Immunomodulatory Role of Lithium

Mood disorders are chronic, recurrent diseases characterized by changes in mood and emotions. The most common are major depressive disorder (MDD) and bipolar disorder (BD). Molecular biology studies have indicated an involvement of the immune system in the pathogenesis of mood disorders, and showed their correlation with altered levels of inflammatory markers and energy metabolism. Previous reports, including meta-analyses, also suggested the role of microglia activation in the M1 polarized macrophages, reflecting the pro-inflammatory phenotype. Lithium is an effective mood stabilizer used to treat both manic and depressive episodes in bipolar disorder, and as an augmentation of the antidepressant treatment of depression with a multidimensional mode of action. This review aims to summarize the molecular studies regarding inflammation, microglia activation and energy metabolism changes in mood disorders. We also aimed to outline the impact of lithium on these changes and discuss its immunomodulatory effect in mood disorders.

The cytokine IL-17A as a marker of treatment resistance in major depressive disorder?

Major depression is a complex disease and-among others, inflammation appears to play an important role in its pathophysiology. In this study, we investigated a broad range of cytokines in depressed patients. Plasma levels of interleukin (IL)-12/ IL-23p40, IL-15, IL-16, IL-17A, IL-1α, IL-7, tumor necrosis factorβ and vascular endothelial growth factor were compared in 48 patients suffering from major depression before, after one and after six weeks of antidepressive treatment in relation to therapy response. Interestingly, the level of IL-17A turned out to rise significantly in the non-responder group compared to responder during antidepressive treatment. IL-17A is a pro-inflammatory cytokine that initiates the production of other cytokines, thereby inducing and mediating immune response. It is also involved in allergic and autoimmune-related diseases. The database investigating the role of IL-17A in major depressive disorder has grown within the last few years comparing levels of this cytokine in depressed patients versus healthy subjects. However, little is known about the expression of IL-17A during the course of antidepressive treatment. In summary, our study provides valuable evidence that this cytokine might serve as a marker of therapy resistance to antidepressants.

Ligands and receptors of the TNF superfamily are decreased in major depression and during early antidepressant therapy

BACKGROUND

The up-regulation of pro-inflammatory agents, amongst them tumor necrosis factor (TNF), may represent low-grade inflammation in major depression. To further elucidate inflammatory mechanisms related to TNF in depression, the aim of the current study was to investigate the involvement of ligands and receptors of the TNF/TNF-receptor-superfamily yet un- or little explored in major depression.

METHODS

Serum levels of ligands (TNF, TNF-related weak inducer of apoptosis [TWEAK], B-cell activating factor [BAFF], tumor necrosis factor superfamily member 14 [TNFSF14; LIGHT], A proliferation-inducing ligand [APRIL]) and receptor molecules (TNF receptor superfamily member 8 [TNFRSF8; sCD30], soluble TNF receptor type 1 [sTNFR1] and type 2 [sTNFR2]) of the TNF/TNF-receptor-superfamily were measured in 50 unmedicated patients suffering from major depression and 48 healthy controls and were reassessed in 37 of the depressed patients two weeks after the initiation of antidepressive treatment.

RESULTS

In comparison to the healthy controls, the interrelated serum levels of TWEAK, BAFF, TNFSF8, sTNFR1 and sTNFR2 were reduced both in the unmedicated and medicated depressed patients. Serum levels of BAFF and TNF significantly increased during the initiation of antidepressive treatment. In the combined sample of unmedicated depressed and healthy controls, but not the separate groups, scores of the BDI-II inversely correlated with levels of TWEAK, BAFF, sTNFR1, sTNFR2 and TNFSF8.

CONCLUSION

The current findings give evidence for a role of the TNF/TNF-receptor-superfamily in the pathophysiology of major depression that may involve reduced tissue regeneration and neurogenesis rather than an acceleration of pro-inflammatory pathways.

Natural killer cells protect white matter integrity in bipolar disorder

BACKGROUND

Bipolar Disorder (BD) associates with disrupted white matter (WM) microstructure and functional connectivity, and with a perturbation of the immune system. Higher cytokines, and reduced T cells, correlated with WM disruption and fMRI responses. A core component of the innate immune system, natural killer (NK) cells were detected in brain parenchyma, but never studied in BD.

METHODS

We studied Diffusion Tensor Imaging (DTI) measures of water diffusion, fMRI corticolimbic functional response and connectivity, and multi-parameter cytofluorometry analysis of NK (CD56⁺) subpopulations, in 30 inpatients with active Bipolar Disorder type I. NK cells were also obtained in 36 healthy controls.

RESULTS

Patients had significantly higher circulating counts of CD56⁺GMCSF⁺, CD56⁺INFγ⁺, and CD56⁺IL17⁺. NK cell levels positively associated to fractional anisotropy (FA) measures. CD56⁺TNFα⁺, CD56⁺INFγ⁺, and CD56⁺GMCSF⁺ directly correlated with FA, and inversely with radial (RD) and mean (MD) diffusivity. Duration of lithium treatment associated with higher CD56⁺TNFα⁺, CD56⁺IL2⁺, and CD56⁺IL4⁺, and positively associated with FA in tracts were NKs had significant effects. A mediation model suggested a partial mediation of CD56⁺TNFα⁺ cells, higher in patients on lithium, on the effects of lithium on FA. Frequencies of the same cytokine-producing NK cells also influenced fMRI cortico-limbic functional connectivity during processing of both, emotional and non-emotional stimuli.

DISCUSSION

Higher circulating cytokine-producing NK cells associated with lithium treatment, and with DTI measures of WM integrity, partially mediating the effect of lithium on WM. The same cells associated with fMRI responses and connectivity, thus suggesting an effect on structural and functional connectomics in BD.

Different levels of pro- and anti-inflammatory cytokines in patients with unipolar and bipolar depression

BACKGROUND

Immune system dysregulation is critical in the physiopathology of major depressive disorder (MDD) and bipolar disorder (BD). However, it is unclear whether both diseases present the same inflammatory patterns during depressive episodes. We explored the differences in pro- and anti-inflammatory cytokines between unipolar and bipolar depression (BDD) and the trajectory of these cytokines after acute-phase treatment.

METHODS

Sixty-four MDD patients, 61 BDD patients, and 62 healthy controls (HCs) were enrolled. We assessed the clinical features and cytokines plasma levels at baseline and week 12. The pro-inflammatory cytokines (IL-6, TNF-α) and anti-inflammatory cytokines (IL-4, IL-13) of all subjects were assessed by multiplexed sandwich ELISA-based quantitative arrays.

RESULTS

Before acute-phase treatment, the initial levels of TNF-α and IL-13 were significantly lower in the BDD patients than in the MDD patients. The results demonstrated that there was no relationship between each cytokine level and clinical features of unipolar and bipolar depressions. After 12 weeks, TNF-α, IL-4, and IL-13 levels became lower in MDD patients than in the other two groups regardless of the patients' response to treatment while the levels of TNF-α and IL-4 increased only in the BDD responders.

LIMITATIONS

The effects of different drugs on inflammatory cytokines in MDD or BDD could not be explored further due to the relatively small sample size.

CONCLUSION

Even within the same depressive states, MDD and BDD patients present different inflammatory features, particularly in regard to pro-inflammatory TNF-α and anti-inflammatory IL-13. In addition, the fluctuations of cytokines induced by medication may provide a hint regarding the prediction of treatment response.

Lithium + Colchicine: A Potential Strategy to Reduce Pro-inflammatory Effects of Lithium Treatment

PURPOSE

Rosenblat and McIntyre (Acta Psychiatr Scand. 2015;132: 180-191) propose that immune disorders are important mediators between bipolar disorders and medical comorbidities. Rosenblat et al (Bipolar Disord. 2016;18:89-101) present a meta-analysis showing that adjunctive anti-inflammatory agents could evoke moderate antidepressant responses in bipolar disorders. We propose using the anti-inflammatory drug colchicine to improve the long-term safety and efficacy of lithium treatment for bipolar disorders.

METHODS

This report is based on searches of the PubMed and Web of Science databases.

RESULTS

Bipolar disorders are associated with significant medical comorbidities such as hypertension, overweight/obesity, diabetes mellitus, metabolic syndrome, and arteriosclerosis, accompanied by enhanced release of pro-inflammatory markers during changes in mood state. During lithium therapy, granulocyte-colony stimulating factor, CD34+ hematopoietic stem/progenitor cells, and neutrophil elastase enter the circulation with activated neutrophils to promote the extravascular migration of activated neutrophils and enhance tissue inflammation. Concurrent treatment with lithium and low-dose colchicine could facilitate the responsiveness of bipolar patients to lithium by reducing leukocyte tissue emigration, the release of neutrophil elastase, and the release of leukocyte pro-inflammatory cytokines such as IL-1β that are regulated by the NLRP3 inflammasome assembly complex.

CONCLUSIONS

Concurrent therapy with lithium and low-dose colchicine could reduce complications involving leukocyte-mediated inflammatory states in bipolar patients and promote patient acceptance and responsiveness to lithium therapy.

Cytokine serum levels remain unchanged during lithium augmentation of antidepressants in major depression

Lithium augmentation (LA) of antidepressants is a first-line therapy in treatment-resistant depression. Immunomodulatory effects of lithium have been described. The cytokine hypothesis of depression postulates that cytokines play a key role in the pathophysiology of depression. Concordantly, it has been shown that proinflammatory cytokine serum levels decrease during antidepressant treatment. The aim of this study was to investigate changes in cytokine serum levels during LA. Serum concentrations of the cytokines interleukin (IL)-2, IL-4, IL-6, IL-8, IL-10, tumour necrosis factor alpha, interferon-gamma, granulocyte and monocyte colony stimulating factor were measured in a total of 95 acutely depressed patients before and after four weeks of LA. Changes in cytokine levels were corrected for the confounding factors severity of depression, treatment response, lithium serum level, gender, age and body mass index in a linear mixed-model analysis. We did not find a significant change in any of the measured cytokine serum levels during LA (p > 0.05). In conclusion, our study does not support the role of cytokine serum levels as a state marker in treatment of depression with LA.

Association of Polygenic Score for Schizophrenia and HLA Antigen and Inflammation Genes With Response to Lithium in Bipolar Affective Disorder: A Genome-Wide Association Study

IMPORTANCE

Lithium is a first-line mood stabilizer for the treatment of bipolar affective disorder (BPAD). However, the efficacy of lithium varies widely, with a nonresponse rate of up to 30%. Biological response markers are lacking. Genetic factors are thought to mediate treatment response to lithium, and there is a previously reported genetic overlap between BPAD and schizophrenia (SCZ).

OBJECTIVES

To test whether a polygenic score for SCZ is associated with treatment response to lithium in BPAD and to explore the potential molecular underpinnings of this association.

DESIGN, SETTING, AND PARTICIPANTS

A total of 2586 patients with BPAD who had undergone lithium treatment were genotyped and assessed for long-term response to treatment between 2008 and 2013. Weighted SCZ polygenic scores were computed at different P value thresholds using summary statistics from an international multicenter genome-wide association study (GWAS) of 36 989 individuals with SCZ and genotype data from patients with BPAD from the Consortium on Lithium Genetics. For functional exploration, a cross-trait meta-GWAS and pathway analysis was performed, combining GWAS summary statistics on SCZ and response to treatment with lithium. Data analysis was performed from September 2016 to February 2017.

MAIN OUTCOMES AND MEASURES

Treatment response to lithium was defined on both the categorical and continuous scales using the Retrospective Criteria of Long-Term Treatment Response in Research Subjects with Bipolar Disorder score. The effect measures include odds ratios and the proportion of variance explained.

RESULTS

Of the 2586 patients in the study (mean [SD] age, 47.2 [13.9] years), 1478 were women and 1108 were men. The polygenic score for SCZ was inversely associated with lithium treatment response in the categorical outcome, at a threshold P < 5 × 10-2. Patients with BPAD who had a low polygenic load for SCZ responded better to lithium, with odds ratios for lithium response ranging from 3.46 (95% CI, 1.42-8.41) at the first decile to 2.03 (95% CI, 0.86-4.81) at the ninth decile, compared with the patients in the 10th decile of SCZ risk. In the cross-trait meta-GWAS, 15 genetic loci that may have overlapping effects on lithium treatment response and susceptibility to SCZ were identified. Functional pathway and network analysis of these loci point to the HLA antigen complex and inflammatory cytokines.

CONCLUSIONS AND RELEVANCE

This study provides evidence for a negative association between high genetic loading for SCZ and poor response to lithium in patients with BPAD. These results suggest the potential for translational research aimed at personalized prescribing of lithium.

Antipsychotic-associated psoriatic rash - a case report

BACKGROUND

Antipsychotics are a heterogeneous group of drugs. Although, antipsychotics have been used for years, unexpected side effects may still occur. With this case report we focus on a possible association between psoriasis and antipsychotics. Data on the patient's course of psychiatric disease, onset of psoriasis and its evolution were extracted from the patient's medical files.

CASE PRESENTATION

We present a case of a 21-year-old female diagnosed with schizophrenia. She was initially treated with quetiapine, and later switched to aripiprazole due to weight gain. After initiation of antipsychotic treatment, the patient suffered from severe psoriasis lesions.

CONCLUSIONS

Antipsychotics may possess immunological properties that may be involved in immune-mediated conditions, such as psoriatic rash. Further studies are warranted to determine causality and mechanism.

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.

Impact of Serum Cytokine Levels on EEG-Measured Arousal Regulation in Patients with Major Depressive Disorder and Healthy Controls

BACKGROUND

In major depressive disorder (MDD), findings include hyperstable regulation of brain arousal measured by electroencephalography (EEG) vigilance analysis and alterations in serum levels of cytokines. It is also known that cytokines affect sleep-wake regulation. This study investigated the relationship between cytokines and EEG vigilance in participants with MDD and nondepressed controls, and the influence of cytokines on differences in vigilance between the two groups.

METHODS

In 60 patients with MDD and 129 controls, 15-min resting-state EEG recordings were performed and vigilance was automatically assessed with the VIGALL 2.0 (Vigilance Algorithm Leipzig). Serum levels of the wakefulness-promoting cytokines interleukin (IL)-4, IL-10, IL-13 and somnogenic cytokines tumor necrosis factor-α, interferon-x03B3; and IL-2 were measured prior to the EEG.

RESULTS

Summed wakefulness-promoting cytokines, but not somnogenic cytokines, were significantly associated with the time course of EEG vigilance in the MDD group only. In both groups, IL-13 was significantly associated with the course of EEG vigilance. In MDD compared to controls, a hyperstable EEG vigilance regulation was found, significant for group and group × time course interaction. After controlling for wakefulness-promoting cytokines, differences in vigilance regulation between groups remained significant.

CONCLUSIONS

The present study demonstrated a relationship between wakefulness-promoting cytokines and objectively measured EEG vigilance as an indicator for brain arousal. Altered brain arousal regulation in MDD gives support for future evaluation of vigilance measures as a biomarker in MDD. Since interactions between cytokines and EEG vigilance only moderately differed between the groups and cytokine levels could not explain the group differences in EEG vigilance regulation, cytokines and brain arousal regulation are likely to be associated with MDD in independent ways.

The effect of mood-stabilizing drugs on cytokine levels in bipolar disorder: A systematic review

OBJECTIVES

Cytokine level alterations suggest a role for the immune system in the pathophysiology of bipolar disorder (BD). Pharmacotherapy is an important confounding factor in clinical research on cytokine levels. In this systematic review we collate the evidence on blood cytokine levels in medication-free BD and the effects of single mood-stabilizing drugs on these levels.

METHODS

A systematic review was conducted according to the PRISMA statement. We searched the Pubmed and Embase databases for clinical studies reporting either on cytokine levels in medication-free BD or on the effects of single mood-stabilizing drugs on cytokine levels in BD.

RESULTS

Of the 564 articles screened, 17 were included. Fourteen articles report on medication-free patients with BD and indicate state-related cytokine alterations. Six articles discuss the effect of lithium. Whereas no data on short-term effects of lithium were found, ≥2 months lithium use in euthymic populations is associated with normal cytokine levels. Two studies report no effect of valproate and no studies were found on carbamazepine, lamotrigine or antipsychotics.

LIMITATIONS

The available studies are characterized by a broad methodological heterogeneity and limited replication between studies.

CONCLUSIONS

This systematic review suggests the presence of state-related cytokine level alterations in medication-free BD with most evidence pointing to a proinflammatory cytokine response in mania. Euthymia and long-term lithium use are associated with normal cytokine levels. To improve our understanding of the impact of mood-stabilizing drugs on cytokine levels, longitudinal studies with medication-free baseline, randomized controlled single-drug treatment protocols and close mood state monitoring are needed.

The role of macrophages in anti-inflammatory activity of antidepressant drugs

Depression is a common disease influencing patients' quality of life, whose etiology involves complex interactions of environmental, genetic and immunological factors. The latter factors include proinflammatory activation of monocytes and macrophages and increased serum levels of proinflammatory cytokines, altogether formulated as the "macrophage theory of depression". Our current review summarizes the impact of the most commonly used antidepressant drugs on the immune response with special emphasis on the role of macrophages in the clinically observed effects. The anti-inflammatory action of antidepressants mainly results from their direct interaction with immune cells and from changes in the concentration and the relations of neurotransmitters sensed by these cells. The summarized data revealed that Mφs are one of the leading cell populations involved in drug-mediated immune effects that can be observed both in subjects with depression as well as in individuals not suffering from depression. Thus, currently reviewed immunomodulatory effects of the experimental use of different antidepressant drugs suggest the possibility of utilizing them in complex therapeutic strategies dedicated to various inflammatory and immune-mediated diseases. It is worth noting that an excessive inflammatory reaction is also associated with the pathogenesis of various cardiovascular, metabolic and neuro-endocrine diseases. Thus, the inclusion of antidepressants in the complex therapy of these disorders may have beneficial effects through the enhancement of the mood of the patient and alleviation of chronic inflammation. On the other hand, presented data suggest that the influence of chronically used antidepressants on anti-microbial and anti-tumor immunity could also be taken into consideration.

Pro- and anti-inflammatory cytokines, but not CRP, are inversely correlated with severity and symptoms of major depression

To clarify findings of elevated cytokine levels in major depression (MD), this study aimed to investigate the relationship between serum levels of cytokines, symptoms of MD and antidepressant treatment outcome. At baseline (T0) and 4 weeks following initiation of antidepressant treatment (T1), levels of tumor necrosis factor (TNF)-α, interferon (IFN)-γ, interleukin (IL)-2, IL-4, IL-5, IL-10, IL-12, IL-13, granulocyte-macrophage-colony-stimulating-factor (GM-CSF), CRP and depression ratings HAMD-17 and BDI-II were assessed in 30 patients with MD and 30 age-and sex-matched controls. At T0, in the patient group, cytokines, but not CRP, negatively correlated with individual BDI-II-items, factors and severities and showed both negative and positive correlations with HAMD-17 items. At T1 and within the controls, no such relationships were observed. At T0 and T1, levels of both pro- and anti-inflammatory cytokines were significantly higher in treatment responders (ΔHAMD-17T0-T1≥50%,n=15) compared to non-responders. When controlled for baseline BDI, differences between groups were only found significant for IL-2 at T0. The results suggest cytokines are not generally pro-depressive but rather relate to more specific regulation of symptoms and severities in MD. Together with the association between cytokines and treatment responder status, these data support cytokines as a promising but still controversial biomarker of depression.

Modulation of triglyceride accumulation in adipocytes by psychopharmacological agents in vitro

Weight gain is a major problem during psychopharmacological treatment. Research has concentrated on the appetite inducing properties and mechanisms of these drugs in the central nervous system. The potential contribution of direct effects of drugs on metabolically relevant peripheral cells such as adipocytes is less well understood. We examined the influence of the antidepressant imipramine, the antipsychotic clozapine, and the mood stabilizer lithium on preadipocytes and adipocytes in vitro, using Simpson-Golabi-Behmel syndrome (SGBS) cells, an established human preadipocyte model. Parameters of cell differentiation and signaling, and cell metabolism were measured. We found significantly increased triglyceride accumulation in adipocytes after supplementation with imipramine and lithium at therapeutic concentrations, compared to non-supplemented control samples. However, gene expression levels of an early marker of adipogenesis, the peroxisome proliferator-activated receptor gamma (PPAR-γ) and a late marker of adipogenesis, the fatty acid binding protein 4 (FABP4), as well as expression of adiponectin (ADIPOQ) did not change significantly in the presence of these psychopharmacological agents. The results suggest a direct influence of imipramine and lithium but not clozapine on fat storage of adipocytes. The underlying mechanisms of fatty acid storage and adipocyte differentiation however remain to be elucidated.

The Historical Development of Immunoendocrine Concepts of Psychiatric Disorders and Their Therapy

Relationships between the central nervous, immune and endocrine systems are a focus of psychiatric research, particularly in depression and schizophrenia. The field has long antecedents. Observed phenomena attributable to these relationships date back to the Neolithic era. Immunoendocrine theories in the broadest sense are recorded in antiquity. In the 19th century, Kraepelin and Wagner-Jauregg reported pioneering clinical observations in psychiatric patients. Von Basedow, Addison and Cushing described psychiatric symptoms in patients suffering from endocrine diseases. The 20th century opened with the identification of hormones, the first, adrenaline, chemically isolated independently by Aldrich und Takamine in 1901. Berson and Yalow developed the radioimmunoassay (RIA) technique in 1959 making it possible to measure levels of hormones and cytokines. These developments have enabled great strides in psychoimmunoendocrinology. Contemporary research is investigating diagnostic and therapeutic applications of these concepts, for example by identifying biomarkers within the endocrine and immune systems and by synthesizing and testing drugs that modulate these systems and show antidepressant or antipsychotic properties.

Assessment of cytokine levels and hs-CRP in bipolar I disorder before and after treatment

We aimed to assess the relationship between cytokine levels and the severity of the manic period in medication free patients. 30 Medication free patients and 28 healthy subjects (HS) were recruited. Plasma levels of pro-inflammatory, anti-inflammatory, inflammatory cytokines, and hs-CRP levels were investigated upon hospital admission, after six weeks follow up in bipolar disease manic episode and the results were compared to HS. The severity of the manic episodes was assessed according to the Young mania rating scale. TNF-α, INF-γ, IL-6 and hs-CRP levels were significantly higher in patients with manic episode of bipolar I disorder before treatment than HS. After treatment the levels of TNF-α, INF-γ, IL-6 and hs-CRP were observed to be significantly decreased. There was no difference between the levels of anti-inflammatory cytokines in patients before or after treatment of bipolar disorder and HS. hs-CRP was observed to be the only parameter correlated with clinical response. The most significant outcome of this study is the correlation between clinical outcome and hs-CRP levels in treatment naive manic episode bipolar type I patients. hs-CRP is the most consistent indicator according to pro-inflammatory, inflammatory and anti-inflammatory cytokines, in predicting treatment outcomes.