Immune variations in bipolar disorder: phasic differences

Evidence for an association between tumor necrosis factor-alpha levels and lithium response

BACKGROUND

The role of inflammation in bipolar disorder has recently emerged as a potential pathophysiological mechanism. Tumor necrosis factor-alpha (TNF-α) modulation may represent a pathogenic molecular target and a biomarker for staging bipolar disorder. In this context, the possible association between lithium response and TNF-α level was examined.

METHODS

Sixty euthymic bipolar patients receiving lithium therapy were recruited for assessment of TNF-α level. The ALDA lithium response scale (LRS) was used to evaluate longitudinal lithium response in bipolar patients, using cut-offs of poor response, partial response and good response. TNF-α level was assessed using enzyme-linked immunosorbent assay.

RESULTS

There was a significant increase in TNF-α level in patients with poor lithium response compared to those with good response, also after controlling for a range of potential confounders (adjusted effect size: 0.47, p=0.011). Partial response showed a directionally similar, but attenuated and statistically inconclusive association (adjusted effect size: 0.16, p=0.326).

LIMITATIONS

Assessment of response was retrospective and natural course cannot be separated easily from treatment response in an observational design. Selection of additional inflammatory markers could provide for a better understanding of underlying immune changes.

CONCLUSIONS

This study strengthens the hypothesis that TNF-α level may mark or mediate lithium response, and that continuous immune imbalance in poor lithium responders may occasion treatment resistance. Further investigation of immune alterations in treatment-resistant bipolar patients may be productive.

Towards a multifactorial approach for prediction of bipolar disorder in at risk populations

BACKGROUND

The high prevalence, recurrence rate, chronicity, and illness burden in bipolar disorder (BD) are well documented. Moreover, insufficient response with conventional pharmacological and manual-based psychosocial interventions, as well as evidence of illness progression and acceleration, invite the need for early detection and primary prevention.

METHODS

Herein we comprehensively review extant studies reporting on a bipolar prodrome. The overarching aim is to propose a predictive algorithm (i.e. prediction of BD in at-risk populations) integrating genetic (i.e. family history), environmental (e.g. childhood maltreatment) and biological markers (i.e. BDNF, inflammatory and oxidative stress markers). Computerized databases i.e. Pubmed, PsychInfo, Cochrane Library and Scielo were searched using the followed terms: bipolar disorder cross-referenced with prodromal, preclinical, at risk mental states, clinical high risk, ultra high risk, biomarkers, brain-derived neurotrophic factor, inflammation, cytokines, oxidative stress, prediction and predictive model.

RESULTS

Available evidence indicates that a prodrome to bipolar disorder exists. Commonly encountered features preceding the onset of a manic episode are affective lability, irritability, anger, depression, anxiety, substance use disorders, sleep disorders, as well as disturbances in attention and cognition. Non-specificity and insufficient sensitivity have hampered the development of an adequate prediction algorithm.

LIMITATIONS

Limitations include biases associated with retrospective studies, poor characterization of clinical high risk, inadequacy of prospective studies regarding sample selection and absence of specificity of risk states.

CONCLUSION

We propose a hypothetical prediction algorithm that is combinatorial in approach that attempts to integrate family history, early adversity, and selected biomarkers.

Novel therapeutic targets in depression: minocycline as a candidate treatment

Mood disorders are marked by high rates of non-recovery, recurrence, and chronicity, which are insufficiently addressed by current therapies. Several patho-etiological models have been proposed that are not mutually exclusive and include but are not limited to the monoamine, inflammatory, neurotrophic, gliotrophic, excitatory, and oxidative stress systems. A derivative of these observations is that treatment(s) which target one or more of these mechanistic steps may be capable of mitigating, or preventing, disparate psychopathological features. Minocycline is an agent with pleiotropic properties that targets multiple proteins and cellular processes implicated in the patho-etiology of mood disorders. Moreover, preclinical and preliminary clinical evidence suggests that minocycline possesses antidepressant properties. Herein, we provide the rationale for conducting a randomized, controlled trial to test the antidepressant properties of minocycline.

The immune theory of psychiatric diseases: a key role for activated microglia and circulating monocytes

This review describes a key role for mononuclear phagocytes in the pathogenesis of major psychiatric disorders. There is accumulating evidence for activation of microglia (histopathology and PET scans) and circulating monocytes (enhanced gene expression of immune genes, an overproduction of monocyte/macrophage-related cytokines) in patients with bipolar disorder, major depressive disorder, and schizophrenia. These data are strengthened by observations in animal models, such as the MIA models, the chronic stress models, and the NOD mouse model. In these animal models of depressive-, anxiety-, and schizophrenia-like behavior, similar activations of microglia and circulating monocytes can be found. These animal models also make in-depth pathogenic studies possible and show that microglia activation impacts neuronal development and function in brain areas congruent with the altered depressive and schizophrenia-like behaviors.

Antibodies to the glutamate receptor in mania

BACKGROUND

There is evidence that the glutamatergic system is involved in the pathophysiology of mania. Antibodies to the NR2 subunits of the N-methyl-D-aspartate (NMDA) receptor have been shown to adversely affect glutamate functioning.

METHODS

We measured serum antibodies to the NR2 peptide of the NMDA receptor in 60 individuals with different subtypes of mania, including schizoaffective cases, who were assessed at up to three time points. We also measured these antibodies in 295 individuals in other psychiatric groups and in 170 non-psychiatric controls. NR2 antibody levels were compared among groups by multivariate analyses and within the mania group by repeated measures analysis of variance.

RESULTS

Individuals with mania had increased levels of antibodies to the NR2 peptide compared to levels in non-psychiatric controls when measured at the time of admission (t = 2.99, p = 0.003) and the time of evaluation (t = 2.57, p = 0.010), but not at follow-up six months later. The levels of antibodies in individuals in other psychiatric groups did not differ significantly from the levels measured in the control population. Within the mania group, there was a significant decrease in antibody levels over the three time points of the study (F = 5.4, df = 2, p = 0.0067).

CONCLUSIONS

NR2 antibodies are elevated during the acute phase of mania but not at follow-up. Our findings support a role for antibodies to the NMDA receptor in the pathogenesis of acute mania.

Markers of gluten sensitivity in acute mania: a longitudinal study

Increased levels of antibodies to gliadin, which is derived from the wheat protein gluten, have been reported in schizophrenia and bipolar disorder in cross-sectional studies. We examined longitudinally the levels of antibody reactivity to gliadin in acute mania. The sample included 60 individuals assessed during a hospital stay for acute mania, 39 at a 6-month follow-up, and a sample of 143 non-psychiatric controls. Antibodies to gliadin were measured by enzyme immunoassay. The relationship of the antibodies to the clinical course of mania was analyzed by the use of regression models. Individuals with mania had significantly increased levels of IgG antibodies to gliadin, but not other markers of celiac disease, at baseline compared with controls in multivariate analyses. However, these levels were not significantly different from those of controls at the six month follow-up. Among the individuals with mania, elevated levels at follow-up were significantly associated with re-hospitalization in the 6-month follow-up period. The monitoring and control of gluten sensitivity may have significant effects on the management of individuals hospitalized with acute mania.

Executive dysfunction in euthymic bipolar disorder patients and its association with plasma biomarkers

BACKGROUND

Despite the old Kraepelinean concept that bipolar disorder (BD) does not evolve with cognitive decline, the presence of cognitive impairment, especially executive dysfunction has been recognized in BD patients. Brain-derived neurotrophic factor (BDNF) and pro-inflammatory molecules are important contributors to the pathophysiology of BD, and imbalance in peripheral levels of these molecules may be implicated in the cognitive decline observed in BD patients. We aimed to investigate the executive performance of BD type I euthymic patients and its relation with the plasma levels of BDNF, TNF-α and its related soluble receptors (sTNFR1 and sTNFR2).

METHODS

We evaluated executive functioning through the Frontal Assessment Battery (FAB). Plasma levels of BDNF, TNF-α, sTNFR1 and sTNFR2 were measured using enzyme-linked immunosorbent assay (ELISA) in 25 euthymic type I BD patients and 25 age and gender matched healthy controls.

RESULTS

BD patients had an impairment in executive functioning (p<0.006), particularly sensitivity of interference (p=0.02), inhibitory control (p=0.02), and increased BDNF plasma levels (p=0.001) in comparison with controls. Plasma levels of TNF-α were correlated with inhibitory control in BD patients (ρ=0.50, p=0.02) while motor programming was negatively correlated with sTNFR2 plasma levels (ρ=-0.47, p=0.02) in controls. Executive function correlated with age and MMSE, but not with BDNF, neither was influenced by psychiatric and clinical comorbidities nor medications in use.

CONCLUSION

BDNF is altered in BD but do not correlate with executive functioning.

Inflammatory markers and their relationships with leptin and insulin from acute mania to full remission in bipolar disorder

BACKGROUND

Weight gain and increased production of leptin may be associated with immuno-modulation and insulin resistance in bipolar disorder. The links among inflammatory markers, leptin, and insulin of bipolar patients from acute mania to full remission remain unclear.

METHODS

Thirty-three healthy, bipolar I patients under 45 years of age were enrolled. We measured the circulating levels of high-sensitivity C-reactive protein (hs-CRP), anti-inflammatory mediators (interleukin-1 receptor antagonist [IL-1Ra] and soluble tumor necrosis factor receptor 1 [sTNF-R1]), leptin, and insulin during acute mania and subsequent partial and full remission. The results were compared with 33 age- and gender-matched healthy subjects.

RESULTS

The levels of IL-1Ra and hs-CRP of bipolar patients in both acute mania and partial remission were significantly higher than their levels of control subjects. The hs-CRP level of bipolar patients was also elevated in full remission. The elevation of IL-1Ra and hs-CRP levels in acute mania was independent of each other. They were also independent of the body mass index (BMI) and levels of leptin and insulin measurements. The levels of leptin were all positively associated with insulin levels in the normal subjects and bipolar patients in three phases. However, a significant relationship between leptin and immunoparameter was only seen in full remission with sTNF-R1 (r=0.51). Furthermore, IL-1Ra was inversely correlated with sTNF-R1 (r=-0.37, p<0.05) during partly remission, and while levels of IL-1Ra tended to normalize when patients remitted, levels of hs-CRP and sTNF-R1 showed the opposite trend.

CONCLUSIONS

Activated inflammation was found in acute mania, as evidenced by high levels of IL-1Ra, hs-CRP, and sTNF-R1. The production of leptin may be more tightly linked to insulin than the immunomodulators. Chronic inflammation may exist in bipolar patients and is reflected by elevations of IL-1Ra and hs-CRP levels in acute mania and persistent higher hs-CRP in full remission.

Affective symptoms are associated with markers of inflammation and immune activation in bipolar disorders but not in schizophrenia

OBJECTIVE

Elevated levels of inflammation are reported in bipolar disorders (BP), but how this relates to affective symptoms is unclear. We aimed to determine if immune markers that consistently have been reported elevated in BP were associated with depressive and manic symptoms, and if this was specific for BP.

METHODS

From a catchment area, 112 BP patients were included together with 153 schizophrenia (SCZ) patients and 239 healthy controls. Depression and mania were assessed and the patients were grouped into depressed, neutral, and elevated mood. We measured the immune markers tumor necrosis factor receptor 1 (sTNF-R1), interleukin 1 receptor antagonist (IL-1Ra), interleukin 6 (IL-6), high sensitive C-reactive protein (hsCRP), osteoprotegerin (OPG) and von Willebrand factor (vWf) which have been found increased in severe mental disorders.

RESULTS

In BP all inflammatory markers were lowest in depressed state, with significant group differences after control for confounders with respect to TNF-R1 (p = 0.04), IL-1Ra (p = 0.02), OPG (p = 0.004) and IL-6 (p = 0.005). STNF-R1 was positively correlated with the item elevated mood (p = 0.02) whereas sad mood was negatively correlated with OPG (p = 0.0003), IL-1Ra (p = 0.001) and IL-6 (p = 0.006). Compared to controls the neutral mood group had significantly higher levels of OPG (p = 0.0003) and IL-6 (p = 0.005), and the elevated mood group had higher levels of TNF-R1 (p = 0.000005) and vWf (p = 0.002). There were no significant associations between affective states orsymptoms in SCZ.

CONCLUSIONS

The current associations between inflammatory markers and affective symptomatology in BP and not SCZ suggest that immune related mechanisms are associated with core psychopathology of BP.

Preliminary findings regarding proinflammatory markers and brain-derived neurotrophic factor among adolescents with bipolar spectrum disorders

Mood symptoms in adult bipolar disorder are associated with increased proinflammatory markers and decreased brain-derived neurotrophic factor (BDNF). We examined serum interleukin-6, high-sensitivity C-reactive protein (hsCRP), and BDNF among 30 bipolar disorder adolescents. Hypomanic/manic symptoms were positively associated with hsCRP. BDNF levels were negatively associated with interleukin-6. Forty percent had cardiovascular high-risk hsCRP levels. Larger longitudinal studies are warranted.

Enhanced peripheral toll-like receptor responses in psychosis: further evidence of a pro-inflammatory phenotype

Low-grade peripheral inflammation is often present in psychotic patients. Toll-like receptors (TLRs) are pattern-recognition molecules that initiate inflammation. Our objective was to investigate the peripheral TLR activity in psychosis. Forty schizophrenia patients, twenty bipolar patients and forty healthy controls (HC) were recruited. Donated whole blood was cultured with TLR agonists for 24 h. Cell supernatants were analysed using a multiplex enzyme-linked immunosorbent assay approach to measure IL-1β, IL-6, IL-8 and tumour necrosis factor-α (TNFα). Plasma was analysed for cytokines, cortisol and acute phase proteins. Here, we show that selective TLR agonist-induced cytokine (IL-1β, IL-6, IL-8 and TNFα) release is enhanced in stimulated whole blood from schizophrenia and bipolar patients compared with HC. An exaggerated release of IL-1β, IL-6 and TNFα following treatment with the TLR2 agonist HKLM was detected in both disorders compared with controls. Enhanced TLR4-induced increases in IL-1β for both disorders coupled with TNFα increases for bipolar patients were observed. TLR8-induced increases in IL-1β for both disorders as well as IL-6 and TNFα increases for bipolar patients were detected. TLR9-induced increases in IL-8 for schizophrenia patients were also observed. No differences in TLR1, TLR3, TLR5, TLR6 or TLR7 activity were detected. Plasma levels of IL-6 were significantly elevated in bipolar patients while TNFα levels were significantly elevated in schizophrenia patients compared with controls. Plasma acute phase proteins were significantly elevated in bipolar patients. These data demonstrate that specific alterations in TLR agonist-mediated cytokine release contribute to the evidence of immune dysfunction in psychotic disorders.

The activation of monocyte and T cell networks in patients with bipolar disorder

OBJECTIVES

We recently described a monocyte pro-inflammatory state in patients with bipolar disorder (BD). We hypothesized that the CD4(+)T cell system is also activated and determined percentages of Th1, Th2, Th17 and CD4(+)CD25(high)FoxP3(+) regulatory T cells.

METHODS

We carried out a detailed FACS analysis to determine the various T cell subsets and used frozen stored peripheral blood mononuclear cells (PBMC) of 38 BD patients (of whom we previously had tested monocytes for pro-inflammatory gene expression (Drexhage et al., 2010b; Padmos et al., 2008)) and of 22 age/gender matched healthy controls (HC). In addition the cytokines CCL2, IL-1β, IL-6, TNF-α, PTX3, IL-10, IFN-γ, IL-17A, IL-4, IL-5 and IL-22 were measured in serum.

RESULTS

(a) Serum sCD25 levels and percentages of anti-inflammatory CD4(+)CD25(high)FoxP3+ regulatory T cells were higher, the latter in BD patients <40 years of age. Percentages of Th1, Th2 and Th17 cells were normal. (b) Of the pro-inflammatory monocyte cytokines CCL2 and PTX3 were raised in serum. (c) The monocyte pro-inflammatory state and the raised percentages of CD4(+)CD25(high)FoxP3(+) regulatory T cells occurred independently from each other. (d) In BD patients positive for thyroid autoimmune disease a significantly reduced percentage of CD4(+)CD25(high)FoxP3(+) regulatory T cells was found as compared to BD patients without AITD.

CONCLUSION

Our data show an enhancement of pro-inflammatory monocyte and anti-inflammatory T cell forces in BD patients. A lack of anti-inflammatory T cell forces co-occurred with AITD in BD patients.

A transdisciplinary perspective of chronic stress in relation to psychopathology throughout life span development

The allostatic load (AL) model represents an interdisciplinary approach to comprehensively conceptualize and quantify chronic stress in relation to pathologies throughout the life cycle. This article first reviews the AL model, followed by interactions among early adversity, genetics, environmental toxins, as well as distinctions among sex, gender, and sex hormones as integral antecedents of AL. We next explore perspectives on severe mental illness, dementia, and caregiving as unique human models of AL that merit future investigations in the field of developmental psychopathology. A complimenting transdisciplinary perspective is applied throughout, whereby we argue that the AL model goes beyond traditional stress–disease theories toward the advancement of person-centered research and practice that promote not only physical health but also mental health.

Increased plasma levels of soluble TNF receptor I in patients with bipolar disorder

Bipolar disorder (BD) has been associated with a proinflammatory state in which TNF-α seems to play a relevant role. The aim of the present study was to evaluate the plasma levels of TNF-α and its soluble receptors (sTNFR1 and sTNFR2) in BD patients in mania and euthymia in comparison with control subjects. We evaluated 53 BD patients (34 in mania and 19 in euthymia) and 38 healthy subjects. All subjects were assessed by the Mini-International Neuropsychiatry Interview (MINI-Plus). Patients were also evaluated by the Young Mania Rating Scale (YMRS) and by Hamilton Depression Rating Scale (HDRS). Plasma TNF-α and its soluble receptors were measured by ELISA. The plasma TNF-α and sTNFR2 levels did not differ between groups, but higher sTNFR1 levels were found in BD patients. Of note, BD patients in mania had higher sTNFR1 levels than BD patients in euthymia and controls. The sTNFR1 and sTNFR2 levels correlated with BD duration, and sTNFR2 levels correlated with age of patients. Our data indicate a proinflammatory status in BD patients during mania and further suggest that inflammatory mechanisms may be involved with the physiopathology of BD.

Maintenance of wintertime vitamin D status with cholecalciferol supplementation is not associated with alterations in serum cytokine concentrations among apparently healthy younger or older adults

Epidemiological studies have shown that low vitamin D status results in impaired immune function and is associated with the prevalence of autoimmune and inflammatory conditions. Vitamin D supplementation has been shown to reduce circulating concentrations of inflammatory markers in such conditions. However, the possible beneficial effect of vitamin D supplementation in the general population, particularly for those individuals living at high latitudes where hypovitaminosis D is common during wintertime, remains unclear. The aim of this study was to assess the effect of vitamin D supplementation using doses of 5, 10, and 15 μg/d cholecalciferol (D3) compared with placebo on cytokine concentrations throughout winter in apparently healthy younger (aged 20-40 y) and older (aged ≥64 y) adults. A total of 211 younger and 202 older adults completed the 22-wk intervention (from October to March) with >85% compliance. Serum concentrations of 25-hydroxycholecalciferol [25(OH)D3], high sensitivity C-reactive protein, IL-6, IL-10, soluble CD40 ligand, TGFβ, TNFα, and fibrinogen were measured using ELISA. 25(OH)D3 concentrations significantly decreased in the placebo and 5 and 10/d μg D3 groups in the younger cohort and in the placebo group in the older cohort. Whereas 15 μg/d D3 supplementation maintained 25(OH)D3 concentrations in the younger cohort (baseline, 75.9 nmol/L; postintervention, 69.0 nmol/L) and significantly increased concentrations in the older cohort (baseline, 55.1 nmol/L; postintervention, 73.9 nmol/L), it had no significant effect on cytokine concentrations (ANCOVA, P > 0.05). The long-term effects of low vitamin D status remain to be elucidated and optimization of vitamin D status in otherwise healthy individuals may potentially have lasting beneficial effects on the immune system.

Elevation of cerebrospinal fluid interleukin-1ß in bipolar disorder

BACKGROUND

In recent years, a role for the immune system in the pathogenesis of psychiatric diseases has gained increased attention. Although bipolar disorder appears to be associated with altered serum cytokine levels, a putative immunological contribution to its pathophysiology remains to be established. Hitherto, no direct analyses of cerebrospinal fluid (CSF) cytokines in patients with bipolar disorder have been performed.

METHODS

We analyzed CSF cytokine concentrations in euthymic patients with diagnosed bipolar disorder type I (n = 15) or type II (n = 15) and healthy volunteers (n = 30) using an immunoassay-based protein array multiplex system.

RESULTS

The mean interleukin (IL)-1ß level (4.2 pg/mL, standard error of the mean [SEM] 0.5) was higher and the IL-6 level (1.5 pg/mL, SEM 0.2) was lower in euthymic bipolar patients than in healthy volunteers (0.8 pg/mL, SEM 0.04, and 2.6 pg/mL, SEM 0.2, respectively). Patients with 1 or more manic/hypomanic episodes during the last year showed significantly higher levels of IL-1ß (6.2 pg/mL, SEM 0.8; n = 9) than patients without a recent manic/hypomanic episode (3.1 pg/mL, SEM 1.0; n = 10).

LIMITATIONS

All patients were in an euthymic state at the time of sampling. Owing to the large variety of drugs prescribed to patients in the present study, influence of medication on the cytokine profile cannot be ruled out.

CONCLUSION

Our findings show an altered brain cytokine profile associated with the manifestation of recent manic/hypomanic episodes in patients with bipolar disorder. Although the causality remains to be established, these findings may suggest a pathophysiological role for IL-1ß in bipolar disorder.

Modulation of the development of human monocyte-derived dendritic cells by lithium chloride

Lithium has been used or explored to treat psychiatric and neurodegenerative diseases that are frequently associated with an abnormal immune status. It is likely that lithium may work through modulation of immune responses in these patients. Because dendritic cells (DC) play a central role in regulating immune responses, this study investigated the influence of lithium chloride (LiCl) on the development and function of DC. Exposure to LiCl during the differentiation of human monocyte-derived immature DCs (iDC) enhances CD86 and CD83 expression and increases the production of IL-1β, IL-6, IL-8, IL-10, and TNF-α. However, the presence of LiCl during LPS-induced maturation of iDC has the opposite effect. During iDC differentiation, LiCl suppresses the activity of glycogen synthase kinase (GSK)-3β, and activates PI3K and MEK. In addition, LiCl activates peroxisome proliferator-activated receptor γ (PPARγ) during iDC differentiation, a pathway not described before. Each of these signaling pathways appears to have distinct impact on the differentiating iDC. The enhanced CD86 expression by LiCl involves the PI3K/AKT and GSK-3β pathway. LiCl modulates the expression of CD83 in iDC mainly through MEK/ERK, PI3K/AKT, and PPARγ pathways, while the increased production of IL-1β and TNF-α mainly involves the MEK/ERK pathway. The effect of LiCl on IL-6/IL-8/IL-10 secretion in iDC is mediated through inhibition of GSK-3β. We have also demonstrated that PPARγ is downstream of GSK-3β and is responsible for the LiCl-mediated modulation of CD86/83 and CD1 expression, but not IL-6/8/10 secretion. The combined influence of these molecular signaling pathways may account for certain clinical effect of lithium.

The role of Wnt signaling and its interaction with diverse mechanisms of cellular apoptosis in the pathophysiology of bipolar disorder

The neurobiology of Bipolar Disorder (BD) is not completely understood, although abnormalities in neuroplasticity and control of apoptosis have been considered as central events in its pathophysiology. The molecules of the Wnt family comprise a class of proteins that control essential developmental processes such as embryonic patterning, cell growth, migration, and differentiation with their actions largely exerted by modulating gene transcription. The Wnt signaling pathway has interface with some mediators with a well documented action in neuroplasticity and regulation of cell surviving. In addition, mood stabilizers such as lithium and valproate may have their neuroprotective properties in part mediated by the Wnt pathway. This article is an overview of how the Wnt signaling cascade might be involved in the pathogenesis of BD and also in details of intracellular events related to this pathway. Further studies of Wnt signaling may lead to a better comprehension of the neuroprotective actions of mood stabilizers and contribute to improving the therapeutics of BD.

Recent advances in psychoneuroimmunology: Inflammation in psychiatric disorders

Psychiatric disorders are common and complex and their precise biological underpinnings remain elusive. Multiple epidemiological, molecular, genetic and gene expression studies suggest that immune system dysfunction may contribute to the risk for developing psychiatric disorders including schizophrenia, bipolar disorder, and major depressive disorder. However, the precise mechanisms by which inflammation-related events confer such risk are unclear. In this review, we examine the peripheral and central evidence for inflammation in psychiatric disorders and the potential molecular mechanisms implicated including inhibition of neurogenesis, apoptosis, the HPA-axis, the role of brain-derived neurotrophic factor and the interplay between the glutamatergic, dopaminergic and serotonergic neurotransmitter systems.

Immune and neuroimmune alterations in mood disorders and schizophrenia

A large number of publications over the past 20 years have indicated that immune system function is altered in schizophrenia and mood disorder patients. This chapter reviews the evidence, which suggests that a proinflammatory state of the cytokine network induces psychopathologic symptoms and may be involved in the pathogenesis and pathophysiology of these major mental illnesses. The authors also present recent data, which relates immune activation to present theories on the influence of activated immune cells in altering brain function. They also focus on the role of the environment in immune activation and on the role of the microbiome and gut flora. Increased understanding of such factors could help in the development of novel treatment strategies and improved clinical management of mental disorders.

Increased risk of gout among patients with bipolar disorder: a nationwide population-based study

This study aims to explore the association between bipolar disorder and the risk of gout using a nationwide population-based dataset. We used the 1996-2006 data from the Taiwan National Health Insurance Research Database. The study cohort comprised 24,262 patients who had visited outpatient departments for the treatment of bipolar disorder in the year 2000. A total of 121,310 enrollees matched with the study group in terms of age and gender, and were selected as the comparison cohort. Each patient was tracked 6 years from the index outpatient visit in 2000 until 2006 to identify all who had developed gout. Cox proportional hazard regressions were performed to compute the 6-year gout-free survival rate, adjusting for other variables. We found that gout occurred among 16.4% of the patients with bipolar disorder and 13.6% of the patients in the comparison cohort between 2000 and 2006 (P<0.001). After adjusting for potential confounders, the regression analysis shows that the hazard of developing gout during the 6-year follow-up period was 1.19 greater (95% confidence interval (CI)=1.10-1.24, P<0.001) for patients with bipolar disorder than their counterparts in the comparison cohort. We conclude that patients with bipolar disorder had increased risk of developing gout even after adjusting for possible confounding factors.

Mood disorders and obesity: understanding inflammation as a pathophysiological nexus

The aim of this review is to evaluate the evidentiary base supporting the hypothesis that the increased hazard for obesity in mood disorder populations (and vice versa) is a consequence of shared pathophysiological pathways. We conducted a PubMed search of all English-language articles with the following search terms: obesity, inflammation, hypothalamic-pituitary-adrenal axis, insulin, cognition, CNS, and neurotransmitters, cross-referenced with major depressive disorder and bipolar disorder. The frequent co-occurrence of mood disorders and obesity may be characterized by interconnected pathophysiology. Both conditions are marked by structural and functional abnormalities in multiple cortical and subcortical brain regions that subserve cognitive and/or affective processing. Abnormalities in several interacting biological networks (e.g. immuno-inflammatory, insulin signaling, and counterregulatory hormones) contribute to the co-occurence of mood disorders and obesity. Unequivocal evidence now indicates that obesity and mood disorders are chronic low-grade pro-inflammatory states that result in a gradual accumulation of allostatic load. Abnormalities in key effector proteins of the pro-inflammatory cascade include, but are not limited to, cytokines/adipokines such as adiponectin, leptin, and resistin as well as tumor necrosis factor alpha and interleukin-6. Taken together, the bidirectional relationship between obesity and mood disorders may represent an exophenotypic manifestation of aberrant neural and inflammatory networks. The clinical implications of these observations are that, practitioners should screen individuals with obesity for the presence of clinically significant depressive symptoms (and vice versa). This clinical recommendation is amplified in individuals presenting with biochemical indicators of insulin resistance and other concurrent conditions associated with abnormal inflammatory signaling (e.g. cardiovascular disease).

Labile anger during interferon alfa treatment is associated with a polymorphism in tumor necrosis factor alpha

OBJECTIVE

Inflammatory cytokines may influence both labile anger and depression. Both psychiatric conditions can occur during interferon alfa-based treatments. Evidence also indicates a central nervous system role for tumor necrosis factor alpha (TNF-alpha), whose expression may be increased by interferon alfa. A polymorphism in the promoter region of TNF-alpha has been associated with various inflammatory illnesses. We therefore hypothesized that this TNF-alpha polymorphism would influence susceptibility to psychiatric symptoms during interferon alfa therapy.

METHODS

One hundred five patients with hepatitis C, initially without active major depression (major depressive disorder), were treated with interferon alfa and then prospectively monitored using the Structured Clinical Interview for Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, the Beck Depression Inventory II, the Anger Irritability and Assault Questionnaire, and circulating TNF-alpha levels. The A-308G polymorphism (rs1800629) was determined using the 5'-nuclease assay. Repeated-measure mixed-effect analyses compared changes in symptoms over time.

RESULT

Beck Depression Inventory II score increased during interferon alfa therapy (F = 6.2; P < 0.001), with 27% developing MDD. The TNF-alpha A allele was associated with worsened labile anger (F = 2.5; P < 0.05) and fatigue (F = 2.9; P < 0.05) during treatment but not with major depression incidence (chi = 0.0; P = 0.99) or increased Beck Depression Inventory II (F = 1.2; P = 0.31). Labile anger was not predicted by the serotonin transporter polymorphism (F = 0.8; P = 0.59).

DISCUSSION

During treatment with an exogenous cytokine, vulnerability to worsening labile anger-distinct from major depression-is associated with genetic variability in TNF-alpha. This has implications both for patients being treated with interferon alfa and our understanding of genetic vulnerability for different subtypes of dysphoric and mood disorders.

Immune activation by casein dietary antigens in bipolar disorder

OBJECTIVES

  Inflammation and other immune processes are increasingly linked to psychiatric diseases. Antigenic triggers specific to bipolar disorder are not yet defined. We tested whether antibodies to bovine milk caseins were associated with bipolar disorder, and whether patients recognized different epitopes of the casein protein than control individuals.

METHODS

  Anti-bovine casein immunoglobulin G (IgG) levels were measured with solid-phase immunoassays in 75 individuals with bipolar disorder and 65 controls. Epitope recognition was evaluated in immunoassays by cross neutralization with anti-bovine casein polyclonal antibodies of defined reactivity. Group-specific reactivity and associations with symptom severity scores were detected with age-, gender-, and race-controlled regression models.

RESULTS

  Individuals with bipolar disorder had significantly elevated anti-casein IgG (t-test, p ≤0.001) compared to controls. Casein IgG seropositivity conferred odds ratios of 3.97 for bipolar disorder [n=75, 95% confidence interval (CI): 1.31-12.08, p ≤0.015], 5.26 for the bipolar I subtype (n=56, 95% CI: 1.66-16.64, p ≤0.005), and 3.98 for bipolar disorder with psychosis (n=54, 95% CI: 1.32-12.00, p ≤0.014). Lithium and/or antipsychotic medication did not significantly affect anti-casein IgG levels. Casein IgG measures correlated with severity of manic (R(2) =0.15, 95% CI: 0.05-0.24, p ≤0.02) but not depressive symptoms. Unlike controls, sera from individuals with bipolar disorder did not inhibit binding of casein-reactive animal sera (t-test/χ(2) , p ≤0.0001).

CONCLUSIONS

  Anti-casein IgG associations with bipolar I diagnoses, psychotic symptom history, and mania severity scores suggest that casein-related immune activation may relate to the psychosis and mania components of this mood disorder. Case-control differences in epitope recognition implicate disease-related alterations in how the casein molecule is digested and/or how resulting casein-derived structures are rendered immunogenic.

Cytokine levels in euthymic bipolar patients

BACKGROUND

The pathophysiology of bipolar disorder is not thoroughly understood. Several studies have investigated the possible role of cytokines in psychiatric disorders, based on their role in neuro-immune modulation; however, findings in studies on bipolar disorder remain limited and contradictory, and most studies have focused on either manic or depressive episodes. These studies suggest that both manic and depressive episodes could be pro-inflammatory states. The present study aimed to determine whether there are enduring differences in cytokine levels-unrelated to the effects of medication-between euthymic bipolar patients and healthy controls.

METHODS

The study included 31 euthymic bipolar patients-16 medication-free (MF) and 15 on lithium monotherapy (LM) and 16 healthy volunteers in whom serum cytokine levels were measured. The 3 groups were homogenous in terms of age, gender, and ethnicity. IFN-γ, TNF-α, IL-2, IL-4, IL-5, and IL-10 levels were measured in all groups using flow cytometry.

RESULTS

There were no differences in cytokine levels between MF euthymic bipolar patients and healthy controls. TNF-α and IL-4 levels in LM euthymic bipolar patients were higher than in both the MF euthymic bipolar patients and controls.

LIMITATIONS

The small and strictly selected study sample could limit the generalizability of the findings.

CONCLUSIONS

Cytokine production in MF euthymic bipolar patients was similar to that in healthy controls. The present study shows that the pro-inflammatory state resolves in euthymia and that lithium had an influence on the cytokine profile, which could create a confounding factor while investigating disease- related immunopathology of bipolar disorder.

Pathways underlying neuroprogression in bipolar disorder: focus on inflammation, oxidative stress and neurotrophic factors

There is now strong evidence of progressive neuropathological processes in bipolar disorder (BD). On this basis, the current understanding of the neurobiology of BD has shifted from an initial focus on monoamines, subsequently including evidence of changes in intracellular second messenger systems and more recently to, incorporating changes in inflammatory cytokines, corticosteroids, neurotrophins, mitochondrial energy generation, oxidative stress and neurogenesis into a more comprehensive model capable of explaining some of the clinical features of BD. These features include progressive shortening of the inter-episode interval with each recurrence, occurring in consort with reduced probability of treatment response as the illness progresses. To this end, emerging data shows that these biomarkers may differ between early and late stages of BD in parallel with stage-related structural and neurocognitive alterations. This understanding facilitates identification of rational therapeutic targets, and the development of novel treatment classes. Additionally, these pathways provide a cogent explanation for the efficacy of seemingly diverse therapies used in BD, that appear to share common effects on oxidative, inflammatory and neurotrophic pathways.

Proinflammatory cytokine levels in fibromyalgia patients are independent of body mass index

Background

Fibromyalgia (FM) is characterized by chronic, widespread muscular pain and tenderness and is generally associated with other somatic and psychological symptoms. Further, circulatory levels of proinflammatory cytokines (IL-1β, TNF-α, and IL-6) may be altered in FM patients, possibly in association with their symptoms. Recently, rises in BMI have been suggested to contribute to increased circulating levels of proinflammatory cytokines in FM patients. Our aim was to measure the circulatory levels of proinflammatory cytokines to determine the influence of BMI on these levels in FM patients and healthy volunteers (HVs). In Spanish FM patients (n = 64) and HVs (n = 25), we measured BMI and serum concentrations of proinflammatory cytokines by capture ELISA.

Findings

There were significant differences in BMI levels between FM patients (26.40 ± 4.46) and HVs (23.64 ± 3.45) and significant increase in IL-6 in FM patients (16.28 ± 8.13 vs 0.92 ± 0.32 pg/ml) (P < 0.001). IL-1β and TNF-α decreased in FM patients compared with HVs. By ANCOVA, there was no significant association between BMI and TNF-α (F = 0.098, p = 0.75) or IL-6 (F = 0.221, p = 0.63) levels in FM patients.

Conclusions

Our analysis in FM patients of BMI as a covariate of proinflammatory cytokines levels showed that serum TNF-α and IL-6 levels are independent of BMI. Further studies are necessary to dissect these findings and their implication in future therapeutic approaches for FM patients.

The mononuclear phagocyte system and its cytokine inflammatory networks in schizophrenia and bipolar disorder

This review describes patients with schizophrenia and bipolar disorder. In such patients, a high inflammatory set point of circulating monocytes at the transcriptome level is observed, involving various inflammatory transcripts forming distinct fingerprints (the transcriptomic monocyte fingerprint in schizophrenia overlaps with that in bipolar disorder, but also differs with it at points). There are increased levels of compounds of the IL-1, IL-6 and TNF system in the serum (be it modest and inconsistent). There is also evidence that the IL-2 system is activated in patients with schizophrenia (and perhaps those with mania), although independently of the activation of the IL-1, IL-6 and TNF systems, suggesting separate inducing mechanisms for monocyte and T-cell activation. It is not yet known whether such T cell activation involves the Th1/Th2/Th17 or Treg systems.

Evaluation of the effect of selective serotonin-reuptake inhibitors on lymphocyte subsets in patients with a major depressive disorder

To date, only the effect of a short-term antidepressant treatment (<12 weeks) on neuroendocrinoimmune alterations in patients with a major depressive disorder has been evaluated. Our objective was to determine the effect of a 52-week long treatment with selective serotonin-reuptake inhibitors on lymphocyte subsets. The participants were thirty-one patients and twenty-two healthy volunteers. The final number of patients (10) resulted from selection and course, as detailed in the enrollment scheme. Methods used to psychiatrically analyze the participants included the Mini-International Neuropsychiatric Interview, Hamilton Depression Scale and Beck Depression Inventory. The peripheral lymphocyte subsets were measured in peripheral blood using flow cytometry. Before treatment, increased counts of natural killer (NK) cells in patients were statistically significant when compared with those of healthy volunteers (312+/-29 versus 158+/-30; cells/mL), but no differences in the populations of T and B cells were found. The patients showed remission of depressive episodes after 20 weeks of treatment along with an increase in NK cell and B cell populations, which remained increased until the end of the study. At the 52nd week of treatment, patients showed an increase in the counts of NK cells (396+/-101 cells/mL) and B cells (268+/-64 cells/mL) compared to healthy volunteers (NK, 159+/-30 cells/mL; B cells, 179+/-37 cells/mL). We conclude that long-term treatment with selective serotonin-reuptake inhibitors not only causes remission of depressive symptoms, but also affects lymphocyte subset populations. The physiopathological consequence of these changes remains to be determined.

Clinical implications of a staging model for bipolar disorders

A model of staging in the field of bipolar disorder (BD) should offer a means for clinicians to predict response to treatment and more general outcome measures, such as the level of functioning and autonomy. The present staging model emphasizes the assessment of patients in the interepisodic period and includes: latent phase: individuals who present mood and anxiety symptoms and increased risk for developing threshold BD; Stage I--patients with BD who present well established periods of euthymia and absence of overt psychiatric morbidity between episodes; Stage II--patients who present rapid cycling or current axis I or II comorbidities; Stage III--patients who present a clinically relevant pattern of cognitive and functioning deterioration, as well as altered biomarkers; and Stage IV--patients who are unable to live autonomously and present altered brain scans and biomarkers. Such a model implies a longitudinal appraisal of clinical variables, as well as assessment of neurocognition and biomarkers in the interepisodic period. Staging facilitates understanding of the mechanisms underlying progression of the disorder, assists in treatment planning and prognosis and, finally, underscores the imperative for early intervention.

Association of genetic polymorphisms in the type II deiodinase gene with bipolar disorder in a subset of Chinese population

OBJECTIVE

Genetic factors play a critical role in the etiology of bipolar disorder (BPAD). Previous studies suggested an association between thyroid dysfunction and BPAD. We hypothesize that genetic variations in the type II deiodinase (DIO2) gene that possibly alter the bioactivity of thyroid hormones are associated with BPAD.

METHOD

A case-control association study was conducted in a subset of Chinese Han population. Two single nucleotide polymorphisms (SNP), open reading frame a (ORFa)-Gly3Asp (rs12885300) and Thr92Ala (rs225014) with potential functions on the activity of DIO2, were selected. The frequencies of allele, genotype and haplotype of the two SNPs were compared between the BPAD patients and the control group.

RESULTS

Statistical significance between the BPAD patients and the control group was observed for the allele (chi(2)=7.746, P=0.005, df=1) and genotype frequencies (chi(2)=8.158, P=0.017, df=2) at the locus of ORFa-Gly3Asp, and for the allele (chi(2)=15.838, P=7.00e-005, df=1) and genotype frequencies (chi(2)=17.236, P=0.0002, df=2) at Thr92Ala. Distribution of allele 3Gly and 92Ala were significantly higher in the BPAD patients, with odds ratios of 1.489 [95% confidence interval (CI)=1.124-1.973] and 1.616 [95% CI=1.275-2.048], respectively. Individuals with two copies of the variant 3Gly or 92Ala were at greater risk of BPAD than individuals with one copy (dose-response manner). Haplotypes ORFa-3Asp-92Ala and ORFa-3Gly-92Ala indicated higher susceptibility for BPAD with odds ratios of 3.759 (95% CI=2.013-7.020) and 1.292 (95% CI=1.017-1.642), respectively, while ORFa-3Asp-92Thr probably played a protective role with an odds ratio of 0.395 (95% CI=0.284-0.549).

CONCLUSION

Data generated from this study supported our hypothesis that genetic variations of the DIO2 gene were associated with BPAD and suggested further consideration on the possible involvement of these functionally active variants in the pathophysiology of BPAD.

Comparison of cytokine levels in depressed, manic and euthymic patients with bipolar disorder

BACKGROUND

The neurobiology of bipolar disorder is not completely understood. Cytokines have received increasing attention as potential mediators of the interaction with immune, neuroendocrine system and specific pathways involved in mood, energy, and activity control. Previous reports have suggested the association of mania and bipolar depression with a proinflammatory state. However, they did not compare cytokine levels in all phases of bipolar disorder.

METHODS

Sixty-one bipolar patients were recruited for assessment of serum cytokine levels. Of these, 14 were in euthymic state, 23 and 24 were in manic and depressive episodes, respectively. A healthy comparison group included 25 healthy volunteers. Cytokines involved in Th1/Th2 balance, such as TNF-alpha, IL-2, IL-4, IL-6, IL-10, IFN-gamma, were examined by flow cytometry.

RESULTS

During mania, proinflammatory cytokines, IL-2, IL-4 and IL-6, were increased in comparison with healthy subjects. Patients in depressive episode showed only increased IL-6 levels. There were no significant differences in cytokine levels between patients in remission and healthy subjects, except for IL-4. Mood symptoms showed a positive correlation with IL-6 and IL-2.

DISCUSSION

These findings suggest that mania, and to a less extent, depression are associated with a proinflammatory state. These changes seem to be related to mood state, as changes in cytokine profile were more pronounced during acute episodes than in euthymia. This study provides further support to investigate the immune system as a target for future treatment development.

Brain-derived neurotrophic factor and inflammatory markers in patients with early- vs. late-stage bipolar disorder

Bipolar I disorder (BD) has a poorer longer-term outcome than previously thought, with persistent cognitive impairment and functional decline. The neurobiological underpinnings that might underlie these changes remain unknown. Changes in brain-derived neurotrophic factor (BDNF) levels and cytokines are potential candidates. The aim of this study was to examine both cytokine and BDNF levels and their relationship in BD patients in the early and late stages of the disorder. We measured serum BDNF, TNF-alpha, IL-6 and IL-10 levels in a total of 60 patients with BD I and we compared those in early stages of illness with those in late stages of illness and also compared both groups with 60 matched healthy controls. BDNF was decreased only in those patients in the late stage of bipolar disorder. Moreover, BDNF levels were negatively correlated with length of illness. In contrast, all interleukins and TNF-alpha were increased in the early stages of BD, compared to controls. While TNF-alpha and IL-6 continued to be significantly higher than controls at late stages of BD, IL-10 did not. When levels were compared between patients at early and late stages of illness, there was a significant decrease in BDNF and IL-6 in the later stage of BD compared to the early stage. Inversely, TNF-alpha showed a significant increase at the later stage. Failure of inflammatory defences in the late stage of the disorder may account for reduction in BDNF and continued elevations in cytokines; thus these may have the potential to serve as markers of illness progression in BD.

Expression of neuronal calcium sensor-1 (NCS-1) is decreased in leukocytes of schizophrenia and bipolar disorder patients

Schizophrenia (SCZ) and bipolar disorder (BPD) are severe illnesses representing an enormous social, familiar and individual burden that affect 1% of the population world-wide. Several evidences indicate abnormalities of the dopamine system in both SCZ and BPD. Neuronal calcium sensor-1 (NCS-1) is a protein that has many functions in neurotransmission such as inhibition of dopamine D(2) receptor desensitization, regulation of ionic channels and enhancement of exocytosis of neurotransmitters. In addition, NCS-1 protein expression and mRNA levels were found increased in pre-frontal cortex (PFC) of SCZ and BPD patients. NCS-1 expression in neural and neuroendocrine cells is well documented and, recently, it was shown that NCS-1 is also expressed in mast cells and neutrophils. NCS-1 has important functions in mast cells since it stimulates Fc epsilon RI-triggered exocytosis and the release of arachidonic acid metabolites. Then, due to the known close relation between the nervous and immune systems, we sought to investigate the NCS-1 expression in lymphocytes and monocytes (CD4+ T lymphocytes, CD56+ NK cells, CD19+ B lymphocytes and CD14+ monocytes) of SCZ and BPD patients. Using flow cytometry, our results have shown that NCS-1 expression was diminished in CD4+T lymphocytes, CD19+ B lymphocytes and CD14+ monocytes of BPD patients and also decreased in CD4+ T lymphocytes and CD56+ NK cells of SCZ patients. Results suggest that immune cells might be a cellular model for studies with SCZ and BPD patients considering NCS-1 functions. Efforts need to be done to investigate the motive of the decreased percentage of immune cells expressing NCS-1 in patients with SCZ and BPD.

Cytoprotective effect of lithium against spontaneous and induced apoptosis of lymphoid cell line MOLT-4

Lithium (Li) is still useful in the treatment of bipolar disorder. Cellular mechanisms of Li action are not fully understood and include some cytoprotective properties. Data concerning Li effect on the apoptotic mechanisms in cells other than neurons are fragmentary and contradictory. We have investigated anti-apoptotic activity of Li in a lymphoid derived MOLT-4 cell line. Spontaneous and camptothecin-induced apoptosis was analyzed in cells treated with 0-20 mM Li carbonate. Early apoptosis was identified as significant mitochondrial depolarization (JC-1 staining). Later stages of apoptosis were estimated with annexin V binding and by the proportion of cells containing sub-G1 amounts of DNA (PI staining). We have observed a biphasic effect of Li on the proportion of spontaneously apoptotic cells;namely, low (therapeutic) concentrations of Li had a significant effect stabilizing the mitochondrial membrane polarization, while 10 and 20mM Li increased apoptosis. The latter could be seen both as mitochondrial depolarization as well as an increased proportion of sub-G1 cells, accompanied by reduced proportion of S phase cells. Li at concentrations above 2 mM had a significant, dose-dependent, anti-apoptotic effect on the cells undergoing camptothecin induced apoptosis. In conclusion, demonstrated cytoprotective effect of Li is at least partially related to stabilization of mitochondrial membrane potential and to the reduction of DNA damaging effects in proliferating cells; both may form part of the mechanism through which Li is useful in therapy of bipolar disorder, but may have more general consequences.

Imunologia do transtorno bipolar

OBJETIVO: Pesquisas recentes têm implicado fatores imunes na patogênese de diversos transtornos neuropsiquiátricos. O objetivo do presente trabalho é revisar os trabalhos que investigaram a associação entre transtorno bipolar e alterações em parâmetros imunes. MÉTODOS: Artigos que incluíam as palavras-chave: "bipolar disorder", "mania", "immunology", "cytokines", "chemokines", "interleukins", "interferon" e "tumor necrosis factor" foram selecionados em uma revisão sistemática da literatura. As bases de dados avaliadas foram MedLine e Scopus, entre os anos de 1980 e 2008. RESULTADOS: Foram identificados 28 trabalhos que estudaram alterações imunes em pacientes com transtorno bipolar. Seis artigos investigaram genes relacionados à resposta imune; cinco, autoanticorpos; quatro, populações leucocitárias; 13, citocinas e/ou moléculas relacionadas à resposta imune e seis, leucócitos de pacientes in vitro. CONCLUSÕES: Embora haja evidências na literatura correlacionando o transtorno bipolar a alterações imunes, os dados não são conclusivos. O transtorno bipolar parece estar associado a níveis mais elevados de autoanticorpos circulantes, assim como à tendência à ativação imune com produção de citocinas pró-inflamatórias e redução de parâmetros anti-inflamatórios.

Episode-specific differential gene expression of peripheral blood mononuclear cells in rapid cycling supports novel treatment approaches

Molecular mechanisms underlying bipolar affective disorders are unknown. Difficulties arise from genetic and phenotypic heterogeneity of patients and the lack of animal models. Thus, we focused on only one patient (n = 1) with an extreme form of rapid cycling. Ribonucleic acid (RNA) from peripheral blood mononuclear cells (PBMC) was analyzed in a three-tiered approach under widely standardized conditions. Firstly, RNA was extracted from PBMC of eight blood samples, obtained on two consecutive days within one particular episode, including two different consecutive depressive and two different consecutive manic episodes, and submitted to (1) screening by microarray hybridizations, followed by (2) detailed bioinformatic analysis, and (3) confirmation of episode-specific regulation of genes by quantitative real-time polymerase chain reaction (qRT-PCR).Secondly, results were validated in additional blood samples obtained one to two years later. Among gene transcripts elevated in depressed episodes were prostaglandin D synthetase (PTGDS) and prostaglandin D2 11-ketoreductase (AKR1C3), both involved in hibernation. We hypothesized them to account for some of the rapid cycling symptoms. A subsequent treatment approach over 5 months applying the cyclooxygenase inhibitor celecoxib (2 x 200 mg daily) resulted in reduced severity rating of both depressed and manic episodes. This case suggests that rapid cycling is a systemic disease, resembling hibernation, with prostaglandins playing a mediator role.

Investigation of serum high-sensitive C-reactive protein levels across all mood states in bipolar disorder

There has been an increasing interest in the role of the immune and inflammatory systems in mood disorders. Mood episodes are associated with changes in acute phase proteins such as high-sensitivity C-reactive protein (hsCRP). The present study investigated serum hsCRP in manic, depressed, and euthymic BD patients as compared to matched healthy controls. Serum hsCRP was assessed using an ultrasensitive assay of particle-enhanced immunoturbidimetric latex agglutination. Serum hsCRP levels were increased in manic BD patients, as compared to euthymic, depressed patients and healthy controls (P < 0.001). These findings add to the notion that changes in the inflammatory system take place during acute episodes of mania.