Impact of mood stabilizers and antiepileptic drugs on cytokine production in-vitro
Introduction
In recent years the pathophysiology of bipolar disorder has been shown to include changes in both the cerebral and peripheral immune system leading to altered cytokine production in the brain and other parts of the body, and preliminary studies have pointed to the efficacy of immunomodulatory therapies in bipolar disorder (Stertz et al., 2013).
An increasing body of evidence indicates a possible causal role for the immune system in epilepsy, too. Cytokines seem to contribute to the development and course of epilepsy (Li et al., 2011, Vezzani et al., 2002).
Inflammatory processes play a role in the pathophysiology of a variety of brain disorders and diseases such as infections and autoimmune diseases of the brain, for example multiple sclerosis (Nylander and Hafler, 2012) or narcolepsy (Himmerich et al., 2006). But also in neurodegenerative diseases such as Alzheimer's disease (Rubio-Perez and Morillas-Ruiz, 2012) and Parkinson's disease (Tufekci et al., 2012). In other affective disorders, such as depression (Himmerich et al., 2008), and in schizophrenic disorders (Himmerich et al., 2012, Müller et al., 2012) the immune system is pivotally involved.
Interestingly, overlapping results regarding the cytokine system have been reported for epilepsy and bipolar disorder, namely alterations of interleukin (IL)-1β, IL-2, IL-4, IL-6, and tumor necrosis factor-α (TNF-α) (Li et al., 2011, Hope et al., 2011, Drexhage et al., 2010, Nelson, 2004, Nowak et al., 2011). However, data regarding IL-2 and IL-4 is limited and the few studies do not show consistent results.
Involvement of IL-17 and IL-22 in the pathogenesis of epilepsy or bipolar disorder has not been investigated. This is of note, because T helper type 17 (TH17) cells which produce IL-17 are implicated in numerous immune and inflammatory processes (Hemdan et al., 2010, Park et al., 2005, Murdaca et al., 2011). IL-17 may play a significant role in autoimmune diseases of the brain such as multiple sclerosis (Park et al., 2005). Another cytokine produced by TH17 cells is IL-22. Studies have indicated the importance of IL-22 in host defense and in the development and pathogenesis of several autoimmune diseases (Pan et al., 2013). Therefore, from a neurological, psychiatric and immunological point of view, IL-1β, IL-2, IL-4, IL-6, IL-17, IL-22 and TNF-α are interesting, suitable and promising research targets in bipolar disorder and epilepsy. Beyond their involvement in the pathophysiology of bipolar disorder and epilepsy, exploring the effects of antiepileptic drugs (AEDs) and lithium on these cytokines may assist in elucidating mechanisms by which these drugs exert their therapeutic effects.
Valproic acid (VPA), carbamazepine (CBZ), and lamotrigine (LTG) are evidence-based treatments for bipolar disorder. There are also indications of therapeutic potential for oxcarbazepine (OXC), topiramate (TPM) and levetiracetam (LEV) in bipolar disorder (Grunze et al., 2013).
In-vitro and in-vivo experiments show that AEDs can affect cytokine levels. In patients with epilepsy, CBZ, VPA and phenytoin were reported to lead to elevated levels of IL-1β, IL-2, IL-5, IL-6 and TNF-α (Andrzejczak, 2011, Basta-Kaim et al., 2008). In-vitro, however, CBZ, VPA and phenobarbital (PB) were reported to inhibit the production of IL-2, IL-4, IL-6 and TNF-α (Andrzejczak, 2011, Yang et al., 1992). In patients with affective disorders, CBZ and lithium led to increased plasma concentrations of TNF-α and its soluble receptors sTNF-R p55 and p75 (Himmerich et al., 2005a). However, in this study, the patients gained weight during treatment, and therefore, the activation of the TNF-α system may be due to activation of macrophages in adipose tissue (Himmerich et al., 2009), or activation of Kupffer cells by inflammatory processes within the liver, caused by nutritional overload from increased appetite caused by these neuropsychopharmacological drugs (Himmerich et al., 2005b).
The discrepancy of results of in-vitro vs. in-vivo experiments enjoins us to interpret the results of in-vitro experiments with caution. Nevertheless, for a deep understanding of the mechanisms how psychopharmacological agents work and lead to side effects, it is important to know their effects on different tissues such as blood, liver or brain tissue. Moreover, in depression and bipolar disorder, the stimulated in-vitro production of cytokines has been shown to differ in patients vs. controls and to change during successful therapy (Krause et al., 2012, Knijff et al., 2007, Seidel et al., 1995). Therefore, stimulated in-vitro production of cytokines may be a biomarker for disorders of the brain. For the correct interpretation of data concerning the in-vitro production of cytokines in patients treated with psychopharmacological agents, it is necessary to know the effects on blood cells alone without the influence of a brain disorder and its improvement during therapy.
To our knowledge, no studies exist focused on the effects of PRM and OXC on cytokine production. The modulation of cytokine production by LTG, TPM and LEV has been subject to small exploratory studies, but not systematically in-vitro or in-vivo (Neuman et al., 2012, Kim et al., 2010, Koçer et al., 2009). Systematic investigation of the modulation of cytokine production by AEDs would clarify whether AEDs with mood stabilizing properties differ from AEDs without clear mood stabilizing effects. It would also be interesting to know whether the pharmacodynamic mode of action of an antiepileptic drug (AED) is associated with its influence on cytokine expression.
Therefore, we systematically measured levels of IL-1β, IL-2, IL-4, IL-6, IL-17, IL-22 and TNF-α in the stimulated blood of 14 healthy female subjects supplemented with various mood stabilizers and AEDs, namely PRM, CBZ, LEV, LTG, VPA, OXC, TPM, PB and lithium in a whole blood assay using the toxic shock syndrome toxin 1 (TSST-1) as stimulant. To reduce inter-individual variability by reducing the influence of age and gender and therefore not disguise the immunological effect of mood stabilizer and AEDs, we only used the blood of young and healthy female subjects. One has to keep in mind while reading this article that this is a pilot study which does not claim to obtain representative data for all ages, sexes and psychiatric conditions.
We recently started to use a whole blood assay with TSST-1-stimulation as an in-vitro approach to test the immunological properties of psychopharmacological agents (Himmerich et al., 2010, Himmerich et al., 2011). TSST-1 is a staphylococcal-secreted exotoxin that is responsible for the toxic shock syndrome. TSST-1 leads to non-specific binding of major histocompatibility complex class II (MHC II) with T cell receptors, resulting in polyclonal T cell activation, stimulation of mononuclear cells and increased cytokine production (Dinges et al., 2000, Kum et al., 1993). Thus, TSST-1 does not specifically lead to T cell activation and is therefore suitable for a pilot study on overall effects of mood stabilizers and AEDs on cytokine production.
Previous in-vitro studies on immunological effects of mood stabilizers used the lectin phytohemagglutinin (PHA) and lipolysaccharide (LPS) (Maes et al., 1999). PHA has similar effects on the immune response to TSST-1 (Micusan et al., 1989). LPS primarily allows the assessment of monocyte responses.
However, these previous studies did not focus on IL-17 and IL-22. Since one innovation of our present study to investigate production of these two TH17 cytokines (Costa et al., 2012), under mood stabilizers and AEDs, we followed a methodology based on our experience using TSST-1 to measure IL-17 production under psychopharmacological agents (Himmerich et al., 2011).
Section snippets
Subjects
14 healthy female subjects between 22 and 47 years of age (mean: 29 ± 6.4 (SD) years). Exclusion criteria were use of illegal drugs or regular alcohol consumption, presence of any immunological, infectious or endocrinological disorder, and a history of psychiatric disorder from an interview by a psychiatrist using the Structured Clinical Interview for DSM-IV (SKID-I; German) (Wittchen et al., 1997).
Experimental procedure
The whole blood assay was performed as described previously (Kirchner et al., 1982, Seidel
General findings
TSST-1 significantly increased the concentration of all cytokines (IL-1β, IL-2, IL-4, IL-6, IL-17, IL-22 and TNF-α), see Table 1 for descriptive statistics of cytokine levels and for the comparison between unstimulated and TSST-1-stimulated blood. Without TSST-1 stimulation, cytokines were not measurable in most samples. For example, IL-22 levels were below the detection level in 12 of 14 unstimulated samples (N = 2; see Table 1), whereas stimulation with TSST-1 rendered IL-22 detectable in
Discussion
The most impressive findings of our in-vitro paradigm to test the influence of AEDs and lithium on cytokine production were: the significant reduction of IL-1β levels by most of the mood stabilizing AEDs; the significant decrease in IL-2 production by all AEDs, but not lithium; and the reduced TNF-α levels under all applied drugs at the maximum therapeutic concentration. A novel finding is that the tested drugs increased IL-22 levels, with the exception of VPA which significantly decreased
Conflict of interest
Prof. Himmerich received speaker honoraria from AstraZeneca and Servier, consulting fees from Bristol-Myers Squibb, and chemical substances for study support from AstraZeneca, Novartis and Wyeth. All other authors reported no biomedical financial interests or potential conflicts of interest.
Role of the funding source
The Claussen-Simon-Foundation did not have any influence on study design, collection, analysis and interpretation of data, writing of the report or in the decision to submit the paper for publication.
Acknowledgment
The study was supported by the Claussen-Simon-Foundation.
References (81)
Epilepsy and pro-inflammatory cytokines. Immunomodulating properties of antiepileptic drugs
Neurologia i Neurochirurgia Polska
(2011)- et al.
A natural immunomodulator of T lymphocytes
Journal of Neuroimmunology
(2008) - et al.
Characterization and gene expression analysis of the two main Th17 cytokines (IL-17A/F and IL-22) in turbot, Scophthalmus maximus
Developmental and Comparative Immunology
(2012) - et al.
Cytokines in schizophrenia and the effects of antipsychotic drugs
Brain, Behaviour and Immunity
(2006) - et al.
Febrile seizures: mechanisms and relationship to epilepsy
Brain & Development
(2009) - et al.
T-lymphocyte invasiveness: control by voltage-gated Na+ channel activity
FEBS Letters
(2004) - et al.
Interleukin-17-producing T helper cells in autoimmunity
Autoimmunity Reviews
(2010) - et al.
Elevation of liver enzyme levels during psychopharmacological treatment is associated with weight gain
Journal of Psychiatric Research
(2005) - et al.
Depression, comorbidities and the TNF-alpha system
European Psychiatry
(2008) - et al.
Impact of antipsychotics on cytokine production in-vitro
Journal of Psychiatric Research
(2011)
In vitro cytokine secretion in individuals with schizophrenia: results, confounding factors, and implications for further research
Brain, Behavior and Immunity
Affective symptoms are associated with markers of inflammation and immune activation in bipolar disorders but not in schizophrenia
Journal of Psychiatric Research
Levetiracetam inhibits interleukin-1 beta inflammatory responses in the hippocampus and piriform cortex of epileptic rats
Neuroscience Letters
A whole-blood technique for testing production of human interferon by leukocytes
Journal of Immunological Methods
Cytokines and epilepsy
Seizure
Inflammation in schizophrenia
Advances in Protein Chemistry and Structural Biology
Cytokines in bipolar disorder: a systematic review and meta-analysis
Journal of Affective Disorders
Genetic and immune predictors for hypersensitivity syndrome to antiepileptic drugs
Translational Research
Is interleukin 2 a neuromodulator in the brain?
Trends in Neurosciences
Interictal alterations of cytokines and leukocytes in patients with active epilepsy
Brain, Behavior and Immunity
Emerging role of interleukin-22 in autoimmune diseases
Cytokine & Growth Factor Reviews
Inflammatory cytokine alterations in schizophrenia: a systematic quantitative review
Biological Psychiatry
Singularities of calcium signaling in effector T-lymphocytes
Biochimica et Biophysica Acta
GABA(A) receptors mediate inhibition of T cell responses
Journal of Neuroimmunology
Inflammation in Parkinson's disease
Advances in Protein Chemistry and Structural Biology
Sleep and epilepsy: opportunities for diagnosis and treatment
Neurologic Clinics
Neuroprotective effect and cognitive outcome of chronic lithium on traumatic brain injury in mice
Brain Research Bulletin
Decreased in vitro production of interferon-gamma and interleukin-2 in whole blood of patients with schizophrenia during treatment
Molecular Psychiatry
Effects of antiepileptic drugs on immune system
Przegla̧d Lekarski
Inhibitory role for GABA in autoimmune inflammation
Proceedings of the National Academy of Sciences of the United States of America
Arbeitsgemeinschaft für Neuropsychopharmakologie und Pharmakopsychiatrie
Pharmacopsychiatry
Nav1.5 sodium channels in macrophages in multiple sclerosis lesions
Multiple Sclerosis
The human macrophage sodium channel NaV1.5 regulates mycobacteria processing through organelle polarization and localized calcium oscillations
FEMS Immunology and Medical Microbiology
Effects of interleukin-2 on various models of experimental epilepsy in DBA/2 mice
Neuroimmunomodulation
Exotoxins of Staphylococcus aureus
Clinical Microbiology Reviews
The mononuclear phagocyte system and its cytokine inflammatory networks in schizophrenia and bipolar disorder
Expert Review of Neurotherapeutics
Physiologically based pharmacokinetics model of primidone and its metabolites phenobarbital and phenylethylmalonamide in humans, rats, and mice
Drug Metabolism and Disposition
Ion channels and transporters in lymphocyte function and immunity
Nature Reviews Immunology
Modulation of the gamma-aminobutyric acid type A receptor by the antiepileptic drugs carbamazepine and phenytoin
Molecular Pharmacology
Relevance of new and newly rediscovered anticonvulsants for atypical forms of bipolar disorder
Journal of Affective Disorders
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Both authors contributed equally to the manuscript.