Plasma levels of tumor necrosis factor-alpha and interleukin-6 in obsessive compulsive disorder

Inflammation in obsessive-compulsive disorder: A literature review and hypothesis-based potential of transcranial photobiomodulation

Obsessive-compulsive disorder (OCD) is a disabling neuropsychiatric disorder that affects about 2%-3% of the global population. Despite the availability of several treatments, many patients with OCD do not respond adequately, highlighting the need for new therapeutic approaches. Recent studies have associated various inflammatory processes with the pathogenesis of OCD, including alterations in peripheral immune cells, alterations in cytokine levels, and neuroinflammation. These findings suggest that inflammation could be a promising target for intervention. Transcranial photobiomodulation (t-PBM) with near-infrared light is a noninvasive neuromodulation technique that has shown potential for several neuropsychiatric disorders. However, its efficacy in OCD remains to be fully explored. This study aimed to review the literature on inflammation in OCD, detailing associations with T-cell populations, monocytes, NLRP3 inflammasome components, microglial activation, and elevated proinflammatory cytokines such as TNF-α, CRP, IL-1β, and IL-6. We also examined the hypothesis-based potential of t-PBM in targeting these inflammatory pathways of OCD, focusing on mechanisms such as modulation of oxidative stress, regulation of immune cell function, reduction of proinflammatory cytokine levels, deactivation of neurotoxic microglia, and upregulation of BDNF gene expression. Our review suggests that t-PBM could be a promising, noninvasive intervention for OCD, with the potential to modulate underlying inflammatory processes. Future research should focus on randomized clinical trials to assess t-PBM's efficacy and optimal treatment parameters in OCD. Biomarker analyses and neuroimaging studies will be important in understanding the relationship between inflammatory modulation and OCD symptom improvement following t-PBM sessions.

New and emerging approaches to treat psychiatric disorders

Psychiatric disorders are highly prevalent, often devastating diseases that negatively impact the lives of millions of people worldwide. Although their etiological and diagnostic heterogeneity has long challenged drug discovery, an emerging circuit-based understanding of psychiatric illness is offering an important alternative to the current reliance on trial and error, both in the development and in the clinical application of treatments. Here we review new and emerging treatment approaches, with a particular emphasis on the revolutionary potential of brain-circuit-based interventions for precision psychiatry. Limitations of circuit models, challenges of bringing precision therapeutics to market and the crucial advances needed to overcome these obstacles are presented.

Early Life Stress, Neuroinflammation, and Psychiatric Illness of Adulthood

Stress exposure during early stages of life elevates the risk of developing psychopathologies and psychiatric illness in later life. The brain and immune system are not completely developed by birth and therefore continue develop after birth; this post birth development is influenced by several psychosocial factors; hence, early life stress (ELS) exposure can alter brain structural development and function. A growing number of experimental animal and observational human studies have investigated the link between ELS exposure and increased risk of psychopathology through alternations in the immune system, by evaluating inflammation biomarkers. Recent studies, including brain imaging, have also shed light on the mechanisms by which both the innate and adaptive immune systems interact with neural circuits and neurotransmitters, which affect psychopathology. Herein, we discuss the link between the experience of stress in early life and lifelong alterations in the immune system, which subsequently lead to the development of various psychiatric illnesses.

Obsessive-Compulsive Disorder, PANDAS, and Tourette Syndrome: Immuno-inflammatory Disorders

In the last years, much focus has been given to the possible role of inflammatory and immunologic alterations in the pathophysiology of obsessive-compulsive disorder (OCD) and some related conditions, such as pediatric autoimmune neuropsychiatric disorders associated with streptococcal infection (PANDAS) and Tourette syndrome (TS). Although the matter is intriguing, the available data are still controversial and/or limited. Therefore, the aim of this chapter was at reviewing and commenting on the literature on possible dysfunctions of inflammatory and immune system processes in OCD, PANDAS, and TS.This narrative review was carried out through searching PubMed and Google Scholar for English language papers from January 1985 to December 31, 2021.The data gathered up to now would suggest that the mechanisms involved might be heterogeneous according to the age of the patients and the disorder examined. Indeed, PANDAS seem more related to infections triggering autoimmunity not necessarily following group A beta-hemolytic streptococcal (GABHS) infection, as supposed in the past. Autoimmunity seems also important in TS, if coupled with an individual vulnerability that can be genetic and/or environmental. The data in adult OCD, albeit scattered and sometimes obtained in small samples of patients, would indicate that immune system and inflammatory processes are involved in the pathophysiology of the disorder. However, it is still unclear to conclude whether they are primary or secondary phenomena.In conclusion, taken together, the current findings pave that way towards novel and promising domains to explore the pathophysiology of OCD and related disorders, as well towards the development of innovative therapeutic strategy beyond current pharmacological paradigms.

Correlations between single nucleotide polymorphisms in obsessive-compulsive disorder with the clinical features or response to therapy

Obsessive-compulsive disorder (OCD) is a debilitating neuropsychiatric disorder, in which the patient endures intrusive thoughts or is compelled to perform repetitive or ritualized actions. Many cases of OCD are considered to be familial or heritable in nature. It has been shown that a variety of internal and external risk factors are involved in the pathogenesis of OCD. Among the internal factors, genetic modifications play a critical role in the pathophysiological process. Despite many investigations performed to determine the candidate genes, the precise genetic factors involved in the disease remain largely undetermined. The present review summarizes the single nucleotide polymorphisms that have been proposed to be associated with OCD symptoms, early onset disease, neuroimaging results, and response to therapy. This information could help us to draw connections between genetics and OCD symptoms, better characterize OCD in individual patients, understand OCD prognosis, and design more targeted personalized treatment approaches.

Differential effects of lipopolysaccharide on cognition, corticosterone and cytokines in socially-housed vs isolated male rats

Social isolation is an established risk factor for mental illness and impaired immune function. Evidence suggests that neuroinflammatory processes contribute to mental illness, possibly via cytokine-induced modulation of neural activity. We examined the effects of lipopolysaccharide (LPS) administration and social home cage environment on cognitive performance in the 5-Choice Serial Reaction Time Task (5CSRTT), and their effects on corticosterone and cytokines in serum and brain tissue. Male Long-Evans rats were reared in pairs or in isolation before training on the 5CSRTT. The effects of saline and LPS (150 µg/kg i.p.) administration on sickness behaviour and task performance were then assessed. LPS-induced sickness behaviour was augmented in socially-isolated rats, translating to increased omissions and slower response times in the 5CSRTT. Both social isolation and LPS administration reduced impulsive responding, while discriminative accuracy remained unaffected. With the exception of reduced impulsivity in isolated rats, these effects were not observed following a second administration of LPS, revealing behavioural tolerance to repeated LPS injections. In a separate cohort of animals, social isolation potentiated the ability of LPS to increase serum corticosterone and IL-6, which corresponded to increased IL-6 in the orbitofrontal and medial prefrontal cortices and the nucleus accumbens. Basal IL-4 levels in the nucleus accumbens were reduced in socially-isolated rats. These findings are consistent with the adaptive response of reduced motivational drive following immune challenge, and identify social isolation as an exacerbating factor. Enhanced IL-6 signalling may play a role in mediating the potentiated behavioural response to LPS administration in isolated animals.

Modulating neuroinflammation in COVID-19 patients with obsessive-compulsive disorder

Exacerbation of symptoms of obsessive-compulsive disorder (OCD) during COVID-19 or new onset of the OCD symptoms resulting from COVID-19 infection is an understudied area of research. It is possible that increased proinflammatory immune status is associated with the onset of obsessive-compulsive symptoms in patients with COVID-19 and that targeted anti-inflammatory treatments for COVID-19 infection can mitigate the new onset of Obsessive-Compulsive (OC) spectrum symptoms. In this review, we cover OCD pathogenesis as related to COVID-19, summarize the impact of cytokines on behavior, and suggest that anti-cytokine treatments can help mitigate post-COVID-19 and new onset of the OC symptoms.

Severe symptoms predict salivary interleukin-6, interleukin-1β, and tumor necrosis factor-α levels in children and youth with obsessive-compulsive disorder

OBJECTIVE

Childhood-onset obsessive-compulsive disorder (OCD) has been associated with immune dysregulation, including aberrant plasma inflammatory markers and increased rates of infectious and immune-mediated disorders. Saliva may provide a minimally-invasive tool for assessing oral mucosal immunity and inflammatory biomarkers in this population. The primary aim of this study was to compare salivary defense proteins and inflammatory mediators in saliva from children and youth with OCD and healthy controls, and evaluate their associations with measures of oral health and OCD phenotype.

METHODS

In this cross-sectional observational study, saliva was collected from 41 children and youth with childhood-onset OCD and 46 healthy controls. Levels of lysozyme, α-amylase, secretory immunoglobulin A (sIgA), C-reactive protein (CRP), interleukin-6 (IL-6), IL-1β, and tumor necrosis factor-α (TNF-α) were quantified by enzyme-linked immunosorbent assays or electrochemiluminescent-based immunoassays.

RESULTS

All analytes were detectable in saliva. When adjusting for salivary flow rate and total protein, multiple linear regression models including demographic variables, oral health measures, and OCD status explained a significant proportion of the variance in IL-6, IL-1β, and sIgA but not TNF-α, CRP, α-amylase, or lysozyme levels. Diagnosis of OCD was associated with significantly higher IL-6 (β = 0.403, p = 0.026), while severity of OCD was a significant predictor of increased cytokines (IL-6, β = 0.325, p = 0.009; IL-1β, β = 0.284, p = 0.020; TNF-α, β = 0.269, p = 0.036), but not other analytes.

CONCLUSION

These data point to the feasibility of analyzing soluble immune mediators in the saliva in childhood-onset OCD, suggesting that pro-inflammatory cytokines are associated with OCD diagnosis and symptom severity. Further work is required to elucidate the factors contributing to this association and implications for clinical practice.

Gene expression study in monocytes: evidence of inflammatory dysregulation in early-onset obsessive-compulsive disorder

Obsessive-compulsive disorder (OCD) has a complex etiology that seems to include immune dysfunction and alterations in circulating monocytes. To investigate the immune basis and the functional dysregulation of monocytes in this disease, we analyzed gene expression in the peripheral monocytes of pediatric patients with OCD (N = 102) compared to controls (N = 47). We examined gene expression in primary cultures of peripheral monocytes from participants, under basal conditions and under exposure to lipopolysaccharide (LPS) to stimulate immune response. Whole-genome expression was assessed in 8 patients and 8 controls. Differentially expressed genes were identified followed by protein-protein interaction network construction and functional annotation analysis to identify the genes and biological processes that are altered in the monocytes of OCD patients. We also explored the expression levels of selected genes in monocytes from the other participants using qPCR. Several changes in gene expression were observed in the monocytes of OCD patients, with several immune processes involved under basal conditions (antigen processing and presentation, regulation of immune system and leukocyte cell adhesion) and after LPS stimulation (immune and inflammatory response, cytokine production and leukocyte activation). Despite the qPCR analysis provided no significant differences between patients and controls, high correlations were observed between the expression levels of some of the genes and inflammatory markers (i.e., T helper 17 and regulatory T cell levels, total monocyte and proinflammatory monocyte subset levels, and the cytokine production by resting and stimulated monocytes) of the study participants. Our findings provide more evidence of the involvement of monocyte dysregulation in early-onset OCD, indicating a proinflammatory predisposition and an enhanced immune response to environmental triggers.

Effects of Celecoxib Adjunct to Selective Serotonin Reuptake Inhibitors on Obsessive-Compulsive Disorder

Introduction:

Inflammatory processes in the brain play an important role in the etiopathogenesis of Obsessive-Compulsive Disorder (OCD). Cyclooxygenase inhibitors, such as celecoxib reduce the production of proinflammatory cytokines. This double-blind study aimed to investigate the effects of adding celecoxib to Selective Serotonin Reuptake Inhibitors (SSRIs)on treating OCD.

Methods:

Sixty patients who met the diagnosis criteria for OCD based on the Diagnostic and Statistical Manual of Mental Disorders -Fourth Edition- Text Revision (DSM-IV-TR) were recruited in the present study. Two psychiatrists independently confirmed the diagnosis by performing structured interviews. The study participants included 23 patients who received SSRIs and celecoxib (400 mg twice daily) and 22 patients in the control group that received SSRIs and placebo. Moreover, at baseline, in weeks 4, 8, and 12, the explored patients were assessed by a psychiatrist using the Yale-Brown Obsessive-Compulsive Scale (Y-BCOS).

Results:

A significant difference was observed in the change of scores on the Y-BOCS in week 12, compared with the onset of the study between the study groups (t= −8.976, df=38, P=0.001). There was a significant difference between the study groups in obsession (F= 49.19, df= 1, P≤0.001), compulsion (F= 13.78, df= 1, P= 0.001), and OCD (F= 57.25, df= 1, P≤0.001), i.e., higher in the celecoxib group.

Conclusion:

This study showed that adjuvant treatment with celecoxib can further improve the symptoms of OCD in individuals receiving SSRIs.

Effects of celecoxib augmentation of antidepressant or anxiolytic treatment on affective symptoms and inflammatory markers in patients with anxiety disorders: exploratory study

Prolonged stress has been associated with elevated levels of circulating proinflammatory cytokines. Cyclo-oxygenase-2 inhibitors such as celecoxib exert anti-inflammatory effects and may enhance the response to antidepressant drug treatment in patients with depressive disorders, but their effect on anxiety symptoms in patients with anxiety disorders is uncertain. Patients with a primary diagnosis of an anxiety disorder, with stabilised symptoms, underwent either 6 weeks of celecoxib augmentation of continued treatment (n = 18) or continued 'treatment as usual' (n = 9). Assessments included the Warwick-Edinburgh mental well-being Scale (WEMWEBS), Hospital Anxiety and Depression Scale (HADS), Oxford questionnaire of emotional side effects of antidepressants (OQUESA) and Clinical Global Impression of Illness Severity (CGI-S). Venous blood samples were collected for assays of inflammatory cytokines. Patients who underwent celecoxib augmentation showed significant reductions in anxiety (HADS-A -3.17) and depressive (HADS-D -2.11) symptoms and in overall illness severity (CGI-S -1.11), and improvements in mental well-being (WEMWBS 7.5) and positive changes in emotional responsiveness (OQUESA-RP -3.56; OQUESA-AC -4.22): these were not seen with 'treatment as usual'. There were no significant changes in blood levels of inflammatory cytokines in either group. Celecoxib augmentation appeared associated with beneficial effects on anxiety and depressive symptoms and mental well-being. The findings from this pilot study merit further exploration within a double-blind, randomised placebo-controlled study.

Peripartum complications associated with obsessive compulsive disorder exacerbation during pregnancy

Prior research has shown that onset or exacerbation of OCD is associated with menstruation, pregnancy, and the post-partum period. However, the underlying cause is unclear. The goal of this study was to assess whether pregnancy and birth complications were associated with OCD symptoms exacerbation, among women with established OCD. Two-hundred and five (n=205) women with OCD retrospectively reported information on their physical and mental health during their first pregnancy. Over a third of the sample (34%) reported an exacerbation in their OCD symptoms. History of pregnancy and birth complications in the first pregnancy were similar between women who did and did not experience symptom exacerbation, with the exception of gestational diabetes, which was significantly more common among women who experienced exacerbation (7% vs 1%, p=0.03). In a multivariable logistic regression model, gestational diabetes remained significantly associated with exacerbation of OCD symptoms (OR=8.44 [95% CI 1.37-77.27]; p=0.03), even after adjusting for maternal age, OCD severity and treatment, premenstrual OCD symptom increase, stress during pregnancy, and major depression or anxiety disorder diagnosis during pregnancy. We discuss potential explanations for this link. These findings should be treated as hypothesis-generating and need to be replicated in a larger, prospective study.

Microstructural white matter abnormalities in pediatric and adult obsessive-compulsive disorder: A systematic review and meta-analysis

OBJECTIVE

To identify the most prominent and replicable fractional anisotropy (FA) alterations of white matter associated with obsessive-compulsive disorder (OCD) in tract-based spatial statistics (TBSS) studies.

METHODS

We reviewed previous TBSS studies (n = 20) in OCD and performed a meta-analysis (n = 16) of FA differences.

RESULTS

No between-group differences in FA were detected in the pooled meta-analysis. However, reduced FA was identified in the genu and anterior body of corpus callosum (CC) in adult OCD. FA reductions in the anterior body of CC were associated with a later age of onset in adult patients with OCD. For pediatric OCD, decreased FA in earlier adolescence and increased FA in later adolescence were seemingly related to an altered trajectory of brain maturation.

CONCLUSIONS

Absent in the pooled sample but robust in adults, disrupted microstructural organization in the anterior part of CC indicates a bias of deficits toward connections in interhemispheric connections of rostral neocortical regions, which could lead to deficits of interhemispheric communication and thus contribute to cognitive and emotional deficits in adult OCD. The correlation between FA in the anterior body of CC and older illness onset suggests that patients with later adult onset of illness may represent a biologically distinct subgroup. For pediatric OCD, alterations in neurodevelopmental maturation may contribute to inconsistent patterns of FA alteration relative to controls during adolescence. While most studies of OCD have emphasized alterations of within hemisphere fronto-striatal circuits, these results indicate that between hemisphere connectivity of this circuitry may also represent important pathophysiology of the illness.

The Psychopharmacology of Obsessive-Compulsive Disorder: A Preclinical Roadmap

This review evaluates current knowledge about obsessive-compulsive disorder (OCD), with the goal of providing a roadmap for future directions in research on the psychopharmacology of the disorder. It first addresses issues in the description and diagnosis of OCD, including the structure, measurement, and appropriate description of the disorder and issues of differential diagnosis. Current pharmacotherapies for OCD are then reviewed, including monotherapy with serotonin reuptake inhibitors and augmentation with antipsychotic medication and with psychologic treatment. Neuromodulatory therapies for OCD are also described, including psychosurgery, deep brain stimulation, and noninvasive brain stimulation. Psychotherapies for OCD are then reviewed, focusing on behavior therapy, including exposure and response prevention and cognitive therapy, and the efficacy of these interventions is discussed, touching on issues such as the timing of sessions, the adjunctive role of pharmacotherapy, and the underlying mechanisms. Next, current research on the neurobiology of OCD is examined, including work probing the role of various neurotransmitters and other endogenous processes and etiology as clues to the neurobiological fault that may underlie OCD. A new perspective on preclinical research is advanced, using the Research Domain Criteria to propose an adaptationist viewpoint that regards OCD as the dysfunction of a normal motivational system. A systems-design approach introduces the security motivation system (SMS) theory of OCD as a framework for research. Finally, a new perspective on psychopharmacological research for OCD is advanced, exploring three approaches: boosting infrastructure facilities of the brain, facilitating psychotherapeutic relearning, and targeting specific pathways of the SMS network to fix deficient SMS shut-down processes. SIGNIFICANCE STATEMENT: A significant proportion of patients with obsessive-compulsive disorder (OCD) do not achieve remission with current treatments, indicating the need for innovations in psychopharmacology for the disorder. OCD may be conceptualized as the dysfunction of a normal, special motivation system that evolved to manage the prospect of potential danger. This perspective, together with a wide-ranging review of the literature, suggests novel directions for psychopharmacological research, including boosting support systems of the brain, facilitating relearning that occurs in psychotherapy, and targeting specific pathways in the brain that provide deficient stopping processes in OCD.

Novel inflammatory targets for immunotherapies in pediatric patients with trichotillomania

Immune dysregulation may be important in the etiology of obsessive-compulsive and related disordersandbody-focusedrepetitivebehaviors, such as Trichotillomania (TTM). The role of inflammation and inflammatory markers in TTM has received relatively little attention. This study was aimed to determine the expression levels of inflammatory markers (i.e. IL-1β, IL-1α, IL-4, IL-6, IL-17, TNF-α and TGF-β) in peripheral blood mononuclear cells of children with TTM and healthy controls and to evaluate their association with clinical variables. Seventy-seven patients with TTM and 107 healthy controls were enrolled in the study. Peripheral blood was collected in standardized conditions. The mean age of patients and controls did not differ significantly (10.8 ± 4.4 and 12.0 ± 3.2 years; respectively). The majority of patients with TTM and controls were females (n = 55, 71.4 % and n = 55, 51.4 %; respectively); with a greater preponderance of females among TTM. Patients with TTM had significantly elevated expression levels of TNF-α, IL-6 and IL-17 compared to controls. However, the expression level of IL-4 was significantly reduced in TTM patients compared to controls. Accordingly, we found a pro-inflammatory state in TTM and those findings may suggest novel treatment options for TTM and further, cross-disciplinary studies focusing on neuro- inflammation in TTM conducted on larger samples are needed.

Interaction between PGRN gene and the early trauma on clinical characteristics in patients with obsessive-compulsive disorder

BACKGROUND

Emerging evidence suggests that obsessive-compulsive disorder (OCD) is caused by a combination of genetic predisposition and environmental factors. In this regard, abnormity of progranulin (PGRN, a key regulator of brain inflammation) and a history of childhood trauma have both been linked to an increased risk of developing OCD. This study is aimed to investigate the association between PGRN and childhood trauma in the development of OCD.

METHODS

We genotyped four single nucleotide polymorphisms (SNPs) covering PGRN in 484 OCD patients and 368 healthy controls. Among the OCD patients, 335 of them accepted clinical assessments in details. Generalized multifactor dimensionality reduction (GDMR) analysis and a general linear model were used to identify gene-environment interactions. The Braineac expression Quantitative Trait Loci (eQTL) dataset was used to analyze the differences in PGRN expression in various brain regions among different genotypes.

RESULTS

Our linkage disequilibrium analysis revealed that rs3859268-rs2879096-rs3785817 combined OCD and control groups constructed one haplotype block. The haplotype analysis suggested that TCA haplotype frequency was associated with the risk of developing OCD (Padj=0.03). The Braineac eQTL database revealed that rs2879096 and rs3785817 might be associated with PGRN expression in the hippocampus (Padj=0.00085, Padj=0.007). Emotional abuse was positively correlated with the obsession subscale and Y-BOCS total scores. Except for common trauma, physical abuse, emotional abuse and sexual trauma were all positively correlated with the BAI and BDI-II scores of OCD patients (all P<0.05). The interaction between emotional abuse and PGRN haplotype was associated with the development of depression symptoms in OCD patients corrected by age (Padj=0.043).

CONCLUSIONS

The PGRN gene and childhood trauma may be closely related to the incidence of OCD, and OCD patients who have experienced more childhood trauma may exhibit a more severe clinical symptom. The interaction between PGRN and the early trauma may play a critical role in the development of depression symptom in OCD patients.

Eating Disorders: An Evolutionary Psychoneuroimmunological Approach

Eating disorders are evolutionarily novel conditions. They lead to some of the highest mortality rates of all psychiatric disorders. Several evolutionary hypotheses have been proposed for eating disorders, but only the intrasexual competition hypothesis is extensively supported by evidence. We present the mismatch hypothesis as a necessary extension to the current theoretical framework of eating disorders. This hypothesis explains the evolutionarily novel adaptive metaproblem that has arisen when mating motives conflict with the large-scale and easy availability of hyper-rewarding but obesogenic foods. This situation is exacerbated particularly in those contemporary environments that are characterized by sedentary lifestyles, ever-present junk foods, caloric surplus and the ubiquity of social comparisons that take place via social media. Our psychoneuroimmunological model connects ultimate-level causation with proximate mechanisms by showing how the adaptive metaproblem between mating motives and food rewards leads to chronic stress and, further, to disordered eating. Chronic stress causes neuroinflammation, which increases susceptibility to OCD-like behaviors that typically co-occur with eating disorders. Chronic stress upregulates the serotonergic system and causes dysphoric mood in anorexia nervosa patients. Dieting, however, reduces serotonin levels and dysphoric mood, leading to a vicious serotonergic-homeostatic stress/starvation cycle whereby cortisol and neuroinflammation increase through stringent dieting. Our psychoneuroimmunological model indicates that between-individual and within-individual variation in eating disorders partially arises from (co)variation in gut microbiota and stress responsivity, which influence neuroinflammation and the serotonergic system. We review the advances that have been made in recent years in understanding how to best treat eating disorders, outlining directions for future clinical research. Current evidence indicates that eating disorder treatments should aim to reduce the chronic stress, neuroinflammation, stress responsivity and gut dysbiosis that fuel the disorders. Connecting ultimate causes with proximate mechanisms and treating biopsychosocial causes rather than manifest symptoms is expected to bring more effective and sophisticated long-term interventions for the millions of people who suffer from eating disorders.

The Glutamate and the Immune Systems: New Targets for the Pharmacological Treatment of OCD

BACKGROUND

In the last decades the pharmacological treatment of obsessivecompulsive disorder (OCD) has been significantly promoted by the effectiveness of selective serotonin (5-HT) reuptake inhibitors (SSRIs) and the subsequent development of the 5-HT hypothesis of OCD. However, since a large majority of patients (between 40% and 60 %) do not respond to SSRIs or strategies based on the modulation of the 5-HT system, it is now essential to search for other possible therapeutic targets.

AIMS

The aim of this paper was to review current literature through a PubMed and Google Scholar search of novel hypotheses and related compounds for the treatment of OCD, with a special focus on the glutammate and the immune systems.

DISCUSSION

The literature indicates that glutamate, the main excitatory neurotransmitter, might play an important role in the pathophysiology of OCD. In addition, a series of clinical studies also supports the potential efficacy of drugs modulating the glutamate system. The role of the immune system alterations in OCD in both children and adults needs to be more deeply elucidated. In children, a subtype of OCD has been widely described resulting from infections driven by group A streptococcus β-hemolitic and belonging to the so-called "pediatric autoimmune neuropsychiatric disorders associated with streptococcus" (PANDAS). In adults, available findings are meager and controversial, although interesting.

CONCLUSION

The glutamate and the immune systems represent two intriguing topics of research that hold promise for the development of open novel treatment strategies in OCD.

The neutrophil-lymphocyte ratio and platelet-lymphocyte ratio in adolescent obsessive-compulsive disorder: Does comorbid anxiety disorder affect inflammatory response?

Recent adult etiologic studies indicated evidence linking increased inflammatory parameters with psychiatric disorders. The neutrophil-lymphocyte ratio and platelet-lymphocyte ratio are easily obtainable clinical markers of inflammation and have been found to be increased in various medical and mental disorders. In this study, we aimed to investigate the neutrophil-lymphocyte ratio and platelet-lymphocyte ratio in adolescents with obsessive-compulsive disorder (OCD). Secondarily, the effect of comorbid anxiety disorder with OCD on the inflammatory response was investigated. Sixty drug-naïve adolescents with OCD aged 12 to 18 years were enrolled in the patient group. Twenty-three of the OCD group had comorbid anxiety disorder (AD) and 37 had no comorbidities. One hundred twenty-eight adolescents in the same age range with no psychiatric disorders were recruited as the healthy control group. The severity of OCD symptoms was evaluated using the Children's Yale-Brown Obsessive Compulsive Scale. There were statistically significant differences in the neutrophil-lymphocyte ratio, white blood cell, neutrophil, and platelet counts among the three groups, even after adjusting for age and sex. The adolescents with OCD and AD had the highest neutrophil-lymphocyte ratio and white blood cell counts. A comorbid anxiety disorder diagnosis in addition to obsessive-compulsive disorder may increase the inflammatory response.

Blood levels of interleukin-1 beta, interleukin-6 and tumor necrosis factor-alpha and cognitive functions in patients with obsessive compulsive disorder

BACKGROUND

Cognitive dysfunction and immune system disorders are two actual issues for the patients with Obsessive Compulsive Disorder (OCD). The cognitive dysfunctions have been considered to substantial part of clinical phenomenon of OCD but exploration of various etiopathogenesis of cognitive dysfunction is needed. Immune dysfuncion has been implicated to be important part of pathopysiology of OCD and different lines of evidence suggests immune abnormalities in OCD. But whether these immune changes are traits of disease or secondary to clinical burden of the disease such as cognitive dysfunctions has not been determined. Data regarding relation between the cognitive dysfunctions and immune system disorders in OCD is unsatisfied. In this study we aimed to investigate the relation of blood levels of interleukin 1-beta (IL-1ß), interleukin-6 (IL-6) and Tumor Necrosis Factor-α (TNF-α) with various neurocognitive functions in patients with OCD in comparison with its autogenous/reactive subtypes and healthy controls. Further exploration of the effects of various clinical variables on cognitive functioning in patients with OCD and additional investigation of whether the cognitive dysfunction associated with this disorder differs from or overlap with that in other anxiety disorders are needed.

METHODS

Forty-two patient with OCD and 45 age, sex and educational level matched healthy control were enrolled in the study. The diagnosis of OCD was made with Structured Clinical Interview for Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV). Yale- Brown Obsessive-Compulsive Scale, Beck Anxiety and Depression Inventory Scales were administered. Neuropsychological test battery including Wisconsin Card Sorting Test (WCST), Trail Making Test A and B (TMT-A, TMT-B) were used for evaluation of the patients and healthy control. The plasma of interleukin-1beta (IL-1ß), interleukin-6 (IL-6), Tumor Necrosis Factor-Alpha (TNF-α) of both groups were measured with ELISA kits.

RESULTS

Blood levels of IL-1ß, IL-6 and TNF-α were significantly higher in patients with OCD than the healthy control. There was significant difference in IL-1ß, IL-6 but not in TNF-α between autogenous/reactive subtypes and healthy controls. TNF-α is positively correlated with TMT-A, TMT-B and Stroop Test Part 5, negatively correlated with immediate memory, verbal learning, interference effect, immediate recall, delayed recall and recognition in RAVLT. IL-1ß was positively correlated with TMT-A score. IL-6 was positively correlated with scores of TMT-A, TMT-B. IL-6 was negatively correlated with immediate memory, verbal learning, interference effect, immediate recall and delayed recall in RAVLT, positively correlated with number of perseverative error and negatively correlated with the number of categories completed in WCST.

CONCLUSION

This is the first study that investigates the relation of IL- 1ß, IL-6 and TNF-α levels with cognitive functions in OCD. There may be a contribution to pathogenesis of OCD and subtypes then new choices for treatment might be developed. Moreover, uncovering the effect of cytokine blood levels on cognitive function of OCD, new data concerning etiopathogenesis and further treatment choices can be gained.

A Clinical Staging Model for Obsessive-Compulsive Disorder: Is It Ready for Prime Time?

Recent changes to the diagnostic classification of obsessive-compulsive disorder (OCD), including its removal from the anxiety/neurotic, stress-related and somatoform disorders chapters of the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5) and International Classification of Diseases 11th Revision (ICD-11), are based on growing evidence of unique pathogenic signatures and linked diagnostic and treatment approaches. In this review, we build on these recent developments and propose a 'clinical staging model' of OCD that integrates the severity of symptoms and phase of illness for personalised case management. A clinical staging model is especially relevant for the early identification and management of subthreshold OCD - a substantial and largely neglected portion of the population who, despite having milder symptoms, experience harms that may impact personal relationships, work-related functioning and productivity. Research on the pathogenesis, classification and management of such cases is needed, including the development of new outcomes measures that prove sensitive to changes in future clinical trials. Early intervention strategies in OCD are likely to yield better long-term outcomes.

Neurobiology and Therapeutic Potential of Cyclooxygenase-2 (COX-2) Inhibitors for Inflammation in Neuropsychiatric Disorders

Neuropsychiatric disorders, such as depression, bipolar disorder, schizophrenia, obsessive-compulsive disorder, and neurodevelopmental disorders such as autism spectrum disorder, are associated with significant illness burden. Accumulating evidence supports an association between these disorders and inflammation. Consequently, anti-inflammatory agents, such as the cyclooxygenase-2 inhibitors, represent a novel avenue to prevent and treat neuropsychiatric illness. In this paper, we first review the role of inflammation in psychiatric pathophysiology including inflammatory cytokines' influence on neurotransmitters, the hypothalamic-pituitary-adrenal axis, and microglial mechanisms. We then discuss how cyclooxygenase-2-inhibitors influence these pathways with potential therapeutic benefit, with a focus on celecoxib, due to its superior safety profile. A search was conducted in PubMed, Embase, and PsychINFO databases, in addition to Clinicaltrials.gov and the Stanley Medical Research Institute trial registries. The results were presented as a narrative review. Currently available outcomes for randomized controlled trials up to November 2017 are also discussed. The evidence reviewed here suggests cyclooxygenase-2 inhibitors, and in particular celecoxib, may indeed assist in treating the symptoms of neuropsychiatric disorders; however, further studies are required to assess appropriate illness stage-related indication.

Haplotypes of TNFα/β Genes Associated with Sex-Specific Paranoid Schizophrenic Risk in Tunisian Population

Several medical research findings have announced a strong association between the biology of cytokines and various brain activities. Since growing evidences suggest the crucial and complex role of the tumor necrosis factor in the CNS, we have hypothesized that functional genetic variants of the LTA and TNFA genes (LTA +252A/G (rs909253) and TNFA -857C/T (rs1799724) and TNFA -238G/A (rs361525)) may be involved in the predisposition to schizophrenia. This research is based on a case-control study. The RFLP-PCR genotyping was conducted on a Tunisian population composed of 208 patients and 208 controls. We found a strong significant overrepresentation of the minor alleles (G, T, and A, respectively) in all patients compared with controls (p = 0.003, OR = 1.55; p = 0.005, OR = 1.78; and p = 0.0001, OR = 1.74, respectively). This correlation was confirmed for male but not for female patients. Interestingly, the frequencies of the minor alleles were significantly more common among patients with paranoid schizophrenia when compared with controls (p = 0.003, OR = 1.75; p = 5 · 10^-6, OR = 3.04; and p = 4 · 10^-6, OR = 2.35, respectively). This potential association was confirmed by a logistic binary regression analysis only for the development of the paranoid form of schizophrenia (p = 0.001/OR = 2.6; p = 0.0002/OR = 3.2; and p = 0.0004/OR = 3.1, respectively) and remained not significant for the other subtypes. Moreover, our study showed an important association between GCA haplotype and the development of this pathological form (p = 10^-4, OR = 3.71). In conclusion, our results proved a significant association between the three polymorphisms and paranoid schizophrenia, at least in the Tunisian population, suggesting a substantially increased risk for paranoid schizophrenia with dominant inheritance of these three minor alleles.

The association between anxiety, traumatic stress, and obsessive-compulsive disorders and chronic inflammation: A systematic review and meta-analysis

BACKGROUND

Anxiety is characterized by prolonged preparation for real or perceived threat. This may manifest both as psychological and physiological activation, ultimately leading to greater risk for poor health. Chronic inflammation may play an integral role in this relationship, given the influential role that it has in chronic illness. The aim of this meta-analysis is to examine levels of chronic inflammation, measured by inflammatory cytokines and C-reactive protein, in people with anxiety disorders, PTSD (posttraumatic stress disorder), or obsessive-compulsive disorder compared to healthy controls. Several moderating variables, including specific diagnosis and depression comorbidity, were also assessed.

METHODS

Seventy six full-text articles were screened for eligibility with 41 studies ultimately included in analysis.

RESULTS

Results demonstrated a significant overall difference between healthy controls (HCs) and people with anxiety disorders in pro-inflammatory cytokines (P = 0.013, Hedge's g = -0.39), which appears to be largely driven by interleukin-1β (IL-1β; P = 0.009, Hedge's g = -0.50), IL-6 (P < 0.001, Hedge's g = -0.93), and tumor necrosis factor-α (P = 0.030, Hedge's g = -0.56). Moderation analyses revealed a moderating effect of diagnosis (P = 0.050), as only individuals with PTSD demonstrated differences in inflammation between HCs (P = 0.004, Hedge's g = -0.68).

CONCLUSIONS

These data demonstrate the association between inflammatory dysregulation and diagnoses associated with chronic, impactful, and severe anxiety and provides insight into the way that anxiety, and in particular PTSD, is related to certain inflammatory markers. In doing so, these findings may provide an initial step in disentangling the relationship between anxiety and basic health processes.

Immune Aberrations in Obsessive-Compulsive Disorder: a Systematic Review and Meta-analysis

Some lines of evidence have indicated that immune dysregulation could play a role in the pathophysiology of obsessive-compulsive disorder (OCD). However, results have been inconsistent across studies. Thus, a systematic review and meta-analysis of studies measuring immune mediators in participants with OCD compared to healthy controls (HC) was conducted. The PubMed/MEDLINE, PsycINFO, and EMBASE electronic databases were systematically searched from inception through June 21, 2018. Sixteen studies met inclusion criteria comprising data from 1001 participants (538 with OCD and 463 were HCs). Levels of TNF-α, IL-6, IL-1β, IL-4, IL-10, and interferon-γ did not significantly differ between participants with OCD and healthy controls. In addition, the ex vivo production of TNF-α and IL-6 by isolated macrophages did not significantly differ between participants with OCD and HCs. Nevertheless, included studies have varied in methodological quality with the enrollment of samples that differed regarding medication status, the proper matching of OCD participants and HCs, age groups, and the presence of psychiatric comorbidities. In conclusion, an association between immune dysregulation and OCD remains unproven. Future studies should consider enrolling larger and more homogeneous samples with OCD.

Individualized Immunological Data for Precise Classification of OCD Patients

Obsessive⁻compulsive disorder (OCD) affects about 2% of the general population, for which several etiological factors were identified. Important among these is immunological dysfunction. This review aims to show how immunology can inform specific etiological factors, and how distinguishing between these etiologies is important from a personalized treatment perspective. We found discrepancies concerning cytokines, raising the hypothesis of specific immunological etiological factors. Antibody studies support the existence of a potential autoimmune etiological factor. Infections may also provoke OCD symptoms, and therefore, could be considered as specific etiological factors with specific immunological impairments. Finally, we underline the importance of distinguishing between different etiological factors since some specific treatments already exist in the context of immunological factors for the improvement of classic treatments.

Salivary Inflammatory Markers in Trichotillomania: A Pilot Study

BACKGROUND

Immune dysregulation has been hypothesized to be important in the development and pathophysiology of compulsive disorders such as obsessive compulsive disorder (OCD), which has a high comorbid overlap with trichotillomania (both are OC-related disorders). The role of inflammation in the pathophysiology of trichotillomania has garnered little research to date.

METHODS

Individuals with trichotillomania provided saliva sample for analysis of inflammatory cytokines. Additionally, these participants were examined on a variety of demographic variables (including body mass index [BMI], previously found to relate to inflammation) along with clinical measures (symptom severity, functioning, and comorbidity).

RESULTS

Thirty-one participants, mean age of 24.7 (±10.2) years, 27 (87.1%) females were -included. The mean score on the Massachusetts General Hospital Hair Pulling Scale was 15.7 (±4.2), reflective of moderate symptom severity. Compared to normative data, the mean inflammatory marker levels in the trichotillomania sample had the following Z scores: interleukin-1β (IL-1β) Z = -0.26, IL-6 Z = -0.39, IL-8 Z = -0.32, and tumor necrosis factor-α Z = -0.83. Levels of inflammatory markers did not correlate significantly with BMI, depressive mood, symptom severity, or disability.

CONCLUSIONS

The relatively low level of inflammatory saliva cytokines observed in the current study (negative z scores versus normative data with medium effect sizes) indicates that evaluation of blood inflammatory levels in trichotillomania versus matched controls would be valuable in future work. If a hypoinflammatory state is confirmed -using blood samples, this would differentiate trichotillomania from other mental disorders (such as OCD, schizophrenia, and depression), which have typically been linked with high inflammatory measures in the literature, at least in some cases.

Cytokine, chemokine and BDNF levels in medication-free pediatric patients with obsessive-compulsive disorder

The aim of this study was to investigate whether the serum levels of IL-12, IL-17, TGFβ, TNF-alpha, sTNFR1, sTNFR2, IL-1β, CCL3, CCL24, CXCL8, and BDNF are associated with obsessive-compulsive disorder (OCD) in medication-free children. A total of 44 (22 boys/22 girls) medication-free children with OCD and 40 (23 boys/17 girls) healthy controls were included in this study. The severity of the OCD symptoms were assessed by the Children's Yale-Brown Obsessive-Compulsive Scale and the Maudsley Obsessive-Compulsive Inventory. The Children's Depression Inventory and the Screen for Child Anxiety-Related Emotional Disorders were applied to the children in order to determine depression and anxiety levels. IL-17, IL-12, TGF β, TNF-alpha, sTNFR1, sTNFR2, IL-1β, CCL3, CCL24, CXCL8, and BDNF levels were measured by enzyme-linked immunosorbent assay. Multivariate analysis of covariance (MANCOVA) revealed a significant main effect on both groups for the levels of serum cytokine, chemokine, and BDNF, an effect that was independent of severities of depression and anxiety [Pillai's Trace V = 0.371, F (11, 70) = 3.756, p < 0.001, hp² = 0.187]. Analysis of covariance (ANCOVA) indicated that serum TNF-alpha levels were significantly higher in the OCD group than in the control group (p < 0.001). In contrast, serum IL-12 levels were significantly lower in the OCD group than in the control group (p = 0.014). These findings suggest that TNF-alpha and IL-12 may play a role in the pathophysiology of OCD in children. The causal relationship between these proinflammatory cytokines and pediatric OCD requires further investigation.

Introducing Transthyretin as a Differentially Expressed Protein in Washing Subtype of Obsessive-Compulsive Disorder

Introduction:

Obsessive-Compulsive Disorder (OCD) as one of the important mental problems is valuable topic for proteomic research studies to better understand the underlying mechanisms of this disorder.

Methods:

In this paper, gel-based proteomic was used to investigate the proteome profile of 16 female patients with OCD, washing subtype before and after treatment with fluoxetine and comparing them with 20 healthy female controls.

Results:

One of the abnormally expressed protein spots in this study was introduced and examined for protein-protein interaction network analysis via Cytoscape and its plug-ins. Transthyretin (TTR) protein showed significant expression changes (fold change=1.7, P<0.05). While the expression level of TTR is significantly decreased in OCD patients before any treatments, the trend is partially normalized after treatment with fluoxetine in positive responders. Furthermore, TTR interaction profile shows that the proteins interacting with this protein may get affected as this protein expression trend changes in OCD patients.

Conclusion:

TTR can be considered for further studies to be validated as a potential biomarker for OCD.

Immune system and obsessive-compulsive disorder

BACKGROUND

Recently, much attention has been devoted to the possible alterations of the immune system in obsessive-compulsive disorder (OCD). Therefore, the aim of this paper was to review the current literature on the relationships between OCD and immune system.

METHODS

A PubMed and Google Scholar search was performed with specific keywords.

RESULTS

In the childhood, much emphasis has been given to the relationship between group A Streptococcus (GAS) infection and the development of a group of clinical syndromes characterized by neuropsychiatric symptoms known as "pediatric autoimmune neuropsychiatric disorders associated with streptococcus" (PANDAS). However, more recently, PANDAS has been reconsidered and evolved towards pediatric acute-onset neuropsychiatric syndrome (PANS) and/or Childhood Acute Neuropsychiatric Syndrome (CANS) all characterized by the presence of typical of OCD symptoms and tics. In adult OCD patients, different immunological parameters have been described to differ from those of healthy control subjects, although a few numbers of studies were carred out and most of them performed in small samples.

CONCLUSIONS

Although the exact relationships between OCD and immune processes are still unclear, available literature supports their role in the pathophysiology of OCD, while providing a fascinating hint for possible immunotherapeutic treatments in OCD.

Association between TNF-α-238G/A gene polymorphism and OCD susceptibility: A meta-analysis

BACKGROUND

Tumor necrosis factor-alpha (TNF-α) is an important cytokine and has been reported to be associated with the pathogenesis of many autoimmune and inflammatory diseases. TNF-α gene is located on a region that has been found to be associated with obsessive-compulsive disorder (OCD). We performed this meta-analysis to assess the relationship between susceptibility to OCD and the TNF-α-238G/A gene polymorphism.

METHODS

An extensive search of the available literature on the association between the susceptibility to OCD and the TNF gene polymorphism was conducted by searching PubMed, Web of Knowledge, Embase, Chinese Web of Knowledge, Wanfang, and Chongqing VIP database. The database was searched up to December 2016 and includes language of English and/or Chinese with the keywords of "obsessive-compulsive disorder" or "OCD," polymorphism or variant or mutation, "tumor necrosis factor" or "TNF" or "cytokine." The association between TNF-α-238G/A gene polymorphism and the susceptibility of OCD was anticipated by odds ratio (OR) with the corresponding 95% confidence interval (95% CI).

RESULTS

Four studies including 435 cases and 1073 controls were incorporated in our meta-analysis. In general, TNF-α-238G/A gene polymorphism might lead to a decreased risk of OCD susceptibility (G vs A genotype model: OR = 1.01, 95% CI = 0.37-2.77, P = .981; GG vs AA+AG model: OR = 0.93, 95% CI = 0.37-2.36, P = .879; GG+AG vs AA model: OR = 0.22, 95% CI = 0.06-0.73, P = .014; GG vs AA model: OR = 0.21, 95% CI = 0.06-0.71, P = .012; AG vs AA model: OR = 0.29, 95% CI = 0.07-1.16, P = .081; GG+AA vs AG model: OR = 1.17, 95% CI = 0.55-2.51, P = .683).

CONCLUSION

TNF-α-238G/A gene polymorphism might lead to a decreased risk of OCD susceptibility.

Neurotrophins and neuroinflammation in fetuses exposed to maternal depression and anxiety disorders during pregnancy: a comparative study on cord blood

In recent years, there have been changes in the approach to maternal psychiatric disorders and their effects on the fetus, with the focus redirected to the search for biological markers. Neurotrophic factors and inflammatory processes have received particular attention in the past few years. According to the Structured Clinical Interview for Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV), the study sample (n = 136) consisted of three groups: mothers with major depressive disorder (MDD group, n = 25), mothers with anxiety disorder (AD group, n = 18), and mothers without any psychiatric disorders (not diagnosed (ND) group, n = 93). During the delivery/cesarean section, a blood sample was obtained from the umbilical cord. Serum concentrations of BDNF, NT-3, FGF2, TNF-α, and neopterin were determined by enzyme-linked immunosorbent assay (ELISA), according to the manufacturer's procedure. Clinical and biochemical characteristics were assessed. We did not find a significant difference among the three study groups with regard to BDNF, NT-3, and TNF-α levels. The ANOVA test indicated statistically significant differences in FGF2 levels and neopterin between the study groups. The newborns of mothers with AD had significantly higher FGF2 levels and significantly higher neopterin levels when compared with those of mothers with MDD and healthy mothers. The present study sheds light on the effects of higher FGF2 and neopterin levels in fetuses exposed to AD. Our results should be replicated through further prospective studies with a larger sample size.

Inflammatory dysregulation of monocytes in pediatric patients with obsessive-compulsive disorder

BACKGROUND

Although the exact etiology of obsessive-compulsive disorder (OCD) is unknown, there is growing evidence of a role for immune dysregulation in the pathophysiology of the disease, especially in the innate immune system including the microglia. To test this hypothesis, we studied inflammatory markers in monocytes from pediatric patients with OCD and from healthy controls.

METHODS

We determined the percentages of total monocytes, CD16+ monocytes, and classical (CD14^highCD16-), intermediate (CD14^highCD16^low), and non-classical (CD14^lowCD16^high) monocyte subsets in 102 patients with early-onset OCD and in 47 healthy controls. Moreover, proinflammatory cytokine production (GM-CSF, IL-1β, IL-6, IL-8, and TNF-α) was measured by multiplex Luminex analysis in isolated monocyte cultures, in basal conditions, after exposure to lipopolysaccharide (LPS) to stimulate immune response or after exposure to LPS and the immunosuppressant dexamethasone.

RESULTS

OCD patients had significantly higher percentages of total monocytes and CD16+ monocytes than healthy controls, mainly due to an increase in the intermediate subset but also in the non-classical monocytes. Monocytes from OCD patients released higher amounts of GM-CSF, IL-1β, IL-6, IL-8, and TNF-α than healthy controls after exposure to LPS. However, there were no significant differences in basal cytokine production or the sensitivity of monocytes to dexamethasone treatment between both groups. Based on monocyte subset distribution and cytokine production after LPS stimulation, patients receiving psychoactive medications seem to have an intermediate inflammatory profile, that is, lower than non-medicated OCD individuals and higher than healthy controls.

CONCLUSIONS

These results strongly support the involvement of an enhanced proinflammatory innate immune response in the etiopathogenesis of early-onset OCD.

Peripheral inflammatory cytokines and immune balance in Generalised Anxiety Disorder: Case-controlled study

INTRODUCTION

Previous investigations have demonstrated that major depression is associated with particular patterns of cytokine signalling. The primary aim of this study was to examine peripheral pro-inflammatory and anti-inflammatory cytokines and immune balance in Generalised Anxiety Disorder (GAD).

METHODS

A case-controlled cross-sectional study design was employed: 54 patients with GAD and 64 healthy controls were recruited. Participants completed self-report measures of anxiety and depression. Two pro-inflammatory and two anti-inflammatory cytokines were measured using multiplex technology.

RESULTS

Case-control logistic regression analyses revealed significant differences in serum levels of IL-10, TNF-α, and IFN-γ between GAD and control groups after adjusting for age, gender, body mass index, smoking and alcohol consumption: these group differences were independent of the presence or degree of depression. Comparison of pro-inflammatory to anti-inflammatory cytokine ratios indicated that there were significantly higher ratios of TNF-α/IL10, TNF-α/IL4, IFN-γ/IL10, and IFN-γ/IL4 in the GAD group compared to the control group.

CONCLUSIONS

This study is the first to investigate both pro- and anti-inflammatory cytokines and their balance in patients with GAD in comparison to healthy controls. The findings indicate a relatively increased pro-inflammatory response and decreased anti-inflammatory response and provide the first demonstration of an altered cytokine balance in GAD. Serum cytokine levels in GAD were independent of the presence of depression.

Microglial NFκB-TNFα hyperactivation induces obsessive-compulsive behavior in mouse models of progranulin-deficient frontotemporal dementia

Frontotemporal dementia (FTD) is the second most common dementia before 65 years of age. Haploinsufficiency in the progranulin (GRN) gene accounts for 10% of all cases of familial FTD. GRN mutation carriers have an increased risk of autoimmune disorders, accompanied by elevated levels of tissue necrosis factor (TNF) α. We examined behavioral alterations related to obsessive-compulsive disorder (OCD) and the role of TNFα and related signaling pathways in FTD patients with GRN mutations and in mice lacking progranulin (PGRN). We found that patients and mice with GRN mutations displayed OCD and self-grooming (an OCD-like behavior in mice), respectively. Furthermore, medium spiny neurons in the nucleus accumbens, an area implicated in development of OCD, display hyperexcitability in PGRN knockout mice. Reducing levels of TNFα in PGRN knockout mice abolished excessive self-grooming and the associated hyperexcitability of medium spiny neurons of the nucleus accumbens. In the brain, PGRN is highly expressed in microglia, which are a major source of TNFα. We therefore deleted PGRN specifically in microglia and found that it was sufficient to induce excessive grooming. Importantly, excessive grooming in these mice was prevented by inactivating nuclear factor κB (NF-κB) in microglia/myeloid cells. Our findings suggest that PGRN deficiency leads to excessive NF-κB activation in microglia and elevated TNFα signaling, which in turn lead to hyperexcitability of medium spiny neurons and OCD-like behavior.

Therapeutic Implications of Brain-Immune Interactions: Treatment in Translation

A wealth of data has been amassed that details a complex, yet accessible, series of pathways by which the immune system, notably inflammation, can influence the brain and behavior. These data have opened the window to a diverse array of novel targets whose potential efficacy is tied to specific neurotransmitters and neurocircuits as well as specific behaviors. What is clear is that the impact of inflammation on the brain cuts across psychiatric disorders and engages dopaminergic and glutamatergic pathways that regulate motivation and motor activity as well as the sensitivity to threat. Given the ability to identify patient populations with increased inflammation, the precision of interventions can be further tuned, in conjunction with the ability to establish target engagement in the brain through the use of multiple neuroimaging strategies. After a brief overview of the mechanisms by which inflammation affects the brain and behavior, this review examines the extant literature on the efficacy of anti-inflammatory treatments, while forging guidelines for future intelligent clinical trial design. An examination of the most promising therapeutic strategies is also provided, along with some of the most exciting clinical trials that are currently being planned or underway.

Serum Cytokine Profiles of Children with Obsessive-Compulsive Disorder Shows the Evidence of Autoimmunity

BACKGROUND

Previous reports have described an association between autoimmunity and primary obsessive compulsive disorder. This study aimed to investigate any differences in the levels of T helper 1, 2, and 17 effector cell cytokines between obsessive compulsive disorder patients and the control group.

METHODS

The study included 34 children (23 males, 11 females), aged between 7 and 17 years, with a diagnosis of obsessive compulsive disorder prior to receiving treatment. The control group consisted of age- and gender-matched children. Study participants were assessed using the Kiddie Schedule for Affective Disorders and Schizophrenia, Present and Lifetime version, Children's Yale Brown Obsession Compulsion Scale, and Children's Depression Inventory. Cytokine serum concentrations were measured using the BD Cytometric Bead Array Human Th1/Th2/Th17 Cytokine Kit.

RESULTS

Interleukin-17A, tumor necrosis factor-α, and interleukin-2 levels were significantly higher in obsessive compulsive disorder patients, However, there was no correlation between T helper 1 and 17 cytokine profiles in the obsessive compulsive disorder group. The duration and severity of obsessive compulsive disorder symptoms were not significantly associated with interleukin-17A, interferon-gamma-γ, interleukin-10, interleukin-6, interleukin-4, and interleukin-2 levels. Interestingly, a negative correlation was found between tumor necrosis factor-α levels and Clinical Global Impression scores.

CONCLUSIONS

These findings suggest, in some cases, obsessive compulsive disorder may develop on a background of autoimmunity, and interleukin-2, tumor necrosis factor-α, and interleukin-17A may play a role in these autoimmune processes. Therefore, we believe it is important to investigate for obsessive compulsive disorder symptoms in patients with autoimmune disease and, conversely, autoimmune diseases in obsessive compulsive disorder patients.

Plasma cytokine abnormalities in drug-naïve, comorbidity-free obsessive-compulsive disorder

Growing evidence in the last decade suggest significant role of immune alterations in the pathogenesis of obsessive-compulsive disorder (OCD). Cytokines, mediators of inflammation, alter the neurotransmitter concentration and result in a hyposerotonergic and hyperglutamatergic state implicated in pathogenesis of OCD. However, only few studies have examined cytokine abnormalities in OCD with inconsistent results possibly due to confounding effects of medications and comorbid anxiety-depression. We examined 20 comorbidity free, drug free OCD patients and 20 age and sex matched healthy controls. Clinical severity was assessed using Yale Brown Obsessive Compulsive Scale, Hamilton anxiety rating scale, Hamilton depression rating scale and Clinical Global Impression. Levels of different cytokines, Interleukin (IL)-2, IL-4, IL-6, IL-10, Tumor necrosis factor (TNF)-α and Interferon (IFN)-γ were assessed using Cytometric Bead Array. OCD patients had significantly greater plasma levels of IL-2, IL-4, IL-6, IL-10 and TNF-α levels than controls but not IFN-γ. Reanalysis of data with only drug naïve patients (excluding 4 drug free patients) did not alter the results. Presence of these abnormalities in drug-naïve patients suggests the possible role of cytokines in the pathogenesis of OCD. Study findings have potential clinical utility in development of novel therapeutic options targeting cytokine aberrations in OCD.

Neuroinflammatory pathways in anxiety, posttraumatic stress, and obsessive compulsive disorders

As prevalence of anxiety, posttraumatic stress, and obsessive compulsive disorders continue to rise worldwide, increasing focus has been placed on immune mediated theories in understanding the underlying mechanisms of these disorders. Associations between the dysregulation of the hypothalamic-pituitary-adrenal (HPA) axis and these disorders have been recognized in the scientific literature, specifically in regard to cortisol levels, as well as changes in pro- and anti-inflammatory cytokines. The present commentary will systematically assess the scientific literature within the past decade in regard to the psychoneuroimmunology of anxiety, posttraumatic stress, and obsessive compulsive disorders. Understanding the mechanisms of these disorders is essential in order to determine efficacious and targeted treatment strategies, which may lead to substantial improvements in overall functioning, as well as significant decreases in societal and economic burden.

Microribonucleic acid dysregulations in children and adolescents with obsessive-compulsive disorder

AIM

Obsessive-compulsive disorder (OCD) is a disorder characterized by the presence of obsessions and/or compulsions. Although disorder etiology and pathogenesis remains unknown, several theories about OCD development have been proposed, and many researchers believe that it is caused by both genetic and environmental factors. In the current study, our aim was to investigate miRNA levels in OCD.

METHODS

In the current study, we evaluated miR18a-5p, miR22-3p, miR24-3p, miR106b-5p, miR107, miR125b-5p, and miR155a-5p levels in child and adolescent OCD patients. The research sample consisted of a group of 23 OCD patients and 40 healthy volunteer controls.

RESULTS

There was no significant difference in age and sex between the two groups (P>0.05). The levels of miR22-3p, miR24-3p, miR106b-5p, miR125b-5p, and miR155a-5p were significantly increased in the OCD subjects (P≤0.05). There were no statistically significant differences in miR18a-5p or miR107 levels between groups (P≥0.05).

CONCLUSION

There could be a close relationship between levels of circulating miRNAs and OCD. If we could understand how the signaling pathways arranged by miRNAs impact on central nervous system development, function, and pathology, this understanding could improve our knowledge about OCD etiology and treatment.

Broken or maladaptive? Altered trajectories in neuroinflammation and behavior after early life adversity

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This paper reviews how early life adversity alters neuroimmune mechanisms.

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Neuroimmune sensitization from early life adversity impacts circuitry at discrete life stages.

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Neuroimmune and neurodevelopmental influences can impact behavior and vulnerability.

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Sexual dimorphism in immune and brain development yield distinct effects of early life adversity.

Exposure to adversity and stress early in development yields vulnerability to mental illnesses throughout the lifespan. Growing evidence suggests that this vulnerability has mechanistic origins involving aberrant development of both neurocircuitry and neuro-immune activity. Here we review the current understanding of when and how stress exposure initiates neuroinflammatory events that interact with brain development. We first review how early life adversity has been associated with various psychopathologies, and how neuroinflammation plays a role in these pathologies. We then summarize data and resultant hypotheses describing how early life adversity may particularly alter neuro-immune development with psychiatric consequences. Finally, we review how sex differences contribute to individualistic vulnerabilities across the lifespan. We submit the importance of understanding how stress during early development might cause outright neural or glial damage, as well as experience-dependent plasticity that may insufficiently prepare an individual for sex-specific or life-stage specific challenges.

An adaptive role of TNFα in the regulation of striatal synapses

Elevation of inflammatory cytokines in the striatum precedes symptoms in a number of motor dysfunctions, but it is unclear whether this is part of the disease process or an adaptive response to the pathology. In pyramidal cells, TNFα drives the insertion of AMPA-type glutamate receptors into synapses, and contributes to the homeostatic regulation of circuit activity in the developing neocortex. Here we demonstrate that in the mouse dorsolateral striatum, TNFα drives the internalization of AMPARs and reduces corticostriatal synaptic strength, dephosphorylates DARPP-32 and GluA1, and results in a preferential removal of Ca(2+)-permeable AMPARs. Striatal TNFα signaling appears to be adaptive in nature, as TNFα is upregulated in response to the prolonged blockade of D2 dopamine receptors and is necessary to reduce the expression of extrapyramidal symptoms induced by chronic haloperidol treatment. These data indicate that TNFα is a regulator of glutamatergic synaptic strength in the adult striatum in a manner distinct from its regulation of synapses on pyramidal cells and mediates an adaptive response during pathological conditions.

Oxidative imbalance and anxiety disorders

The oxidative imbalance appears to have an important role in anxiety development. Studies in both humans and animals have shown a strong correlation between anxiety and oxidative stress. In humans, for example, the increased malondialdehyde levels and discrepancies in antioxidant enzymes in erythrocytes have been observed. In animals, several studies also show that anxiety-like behavior is related to the oxidative imbalance. Moreover, anxiety-like behavior can be caused by pharmacological-induced oxidative stress. Studies using knockout or overexpression of antioxidant enzymes have shown a relationship between anxiety-like behavior and oxidative stress. Related factors of oxidative stress that could influence anxious behavior are revised, including impaired function of different mitochondrial proteins, inflammatory cytokines, and neurotrophic factors. It has been suggested that a therapy specifically focus in reducing reactive species production may have a beneficial effect in reducing anxiety. However, the neurobiological pathways underlying the effect of oxidative stress on anxiety symptoms are not fully comprehended. The challenge now is to identify the oxidative stress mechanisms likely to be involved in the induction of anxiety symptoms. Understanding these pathways could help to clarify the neurobiology of the anxiety disorder and provide tools for new discovery in therapies and preventive strategies.

Reversal of established traumatic brain injury-induced, anxiety-like behavior in rats after delayed, post-injury neuroimmune suppression

Abstract Traumatic brain injury (TBI) increases the risk of neuropsychiatric disorders, particularly anxiety disorders. Yet, there are presently no therapeutic interventions to prevent the development of post-traumatic anxiety or effective treatments once it has developed. This is because, in large part, of a lack of understanding of the underlying pathophysiology. Recent research suggests that chronic neuroinflammatory responses to injury may play a role in the development of post-traumatic anxiety in rodent models. Acute peri-injury administration of immunosuppressive compounds, such as Ibudilast (MN166), have been shown to prevent reactive gliosis associated with immune responses to injury and also prevent lateral fluid percussion injury (LFPI)-induced anxiety-like behavior in rats. There is evidence in both human and rodent studies that post-traumatic anxiety, once developed, is a chronic, persistent, and drug-refractory condition. In the present study, we sought to determine whether neuroinflammation is associated with the long-term maintenance of post-traumatic anxiety. We examined the efficacy of an anti-inflammatory treatment in decreasing anxiety-like behavior and reactive gliosis when introduced at 1 month after injury. Delayed treatment substantially reduced established LFPI-induced freezing behavior and reactive gliosis in brain regions associated with anxiety and continued neuroprotective effects were evidenced 6 months post-treatment. These results support the conclusion that neuroinflammation may be involved in the development and maintenance of anxiety-like behaviors after TBI.

A case-control association study between Obsessive-Compulsive Disorder (OCD) and the MCP-1 -2518G/A polymorphism in a Chinese sample

OBJECTIVE

To investigate the association between Obsessive-Compulsive Disorder (OCD) and a functional polymorphism of MCP-1 in the Chinese Han population.

METHOD

We genotyped and performed a case-control association analysis of the MCP-1 -2518G/A polymorphism in 200 OCD patients and 294 healthy control subjects.

RESULTS

There was no significant difference in MCP-1 -2518G/A genotypic and allelic frequencies between OCD cases and controls (x² = 1.123, df = 2, P = 0.57 by genotype; x² = 0.802, df = 1, P = 0.37 by allele).

CONCLUSIONS

Our results indicated that MCP-1 -2518G/A may not play a major role in the genetic predisposition of the Chinese Han population to OCD. However, further studies using a larger number of subjects are required to obtain a clear conclusion.

How cigarette smoking may increase the risk of anxiety symptoms and anxiety disorders: a critical review of biological pathways

Multiple studies have demonstrated an association between cigarette smoking and increased anxiety symptoms or disorders, with early life exposures potentially predisposing to enhanced anxiety responses in later life. Explanatory models support a potential role for neurotransmitter systems, inflammation, oxidative and nitrosative stress, mitochondrial dysfunction, neurotrophins and neurogenesis, and epigenetic effects, in anxiety pathogenesis. All of these pathways are affected by exposure to cigarette smoke components, including nicotine and free radicals. This review critically examines and summarizes the literature exploring the role of these systems in increased anxiety and how exposure to cigarette smoke may contribute to this pathology at a biological level. Further, this review explores the effects of cigarette smoke on normal neurodevelopment and anxiety control, suggesting how exposure in early life (prenatal, infancy, and adolescence) may predispose to higher anxiety in later life. A large heterogenous literature was reviewed that detailed the association between cigarette smoking and anxiety symptoms and disorders with structural brain changes, inflammation, and cell-mediated immune markers, markers of oxidative and nitrosative stress, mitochondrial function, neurotransmitter systems, neurotrophins and neurogenesis. Some preliminary data were found for potential epigenetic effects. The literature provides some support for a potential interaction between cigarette smoking, anxiety symptoms and disorders, and the above pathways; however, limitations exist particularly in delineating causative effects. The literature also provides insight into potential effects of cigarette smoke, in particular nicotine, on neurodevelopment. The potential treatment implications of these findings are discussed in regards to future therapeutic targets for anxiety. The aforementioned pathways may help mediate increased anxiety seen in people who smoke. Further research into the specific actions of nicotine and other cigarette components on these pathways, and how these pathways interact, may provide insights that lead to new treatment for anxiety and a greater understanding of anxiety pathogenesis.

Neuroinflammation and psychiatric illness

Multiple lines of evidence support the pathogenic role of neuroinflammation in psychiatric illness. While systemic autoimmune diseases are well-documented causes of neuropsychiatric disorders, synaptic autoimmune encephalitides with psychotic symptoms often go under-recognized. Parallel to the link between psychiatric symptoms and autoimmunity in autoimmune diseases, neuroimmunological abnormalities occur in classical psychiatric disorders (for example, major depressive, bipolar, schizophrenia, and obsessive-compulsive disorders). Investigations into the pathophysiology of these conditions traditionally stressed dysregulation of the glutamatergic and monoaminergic systems, but the mechanisms causing these neurotransmitter abnormalities remained elusive. We review the link between autoimmunity and neuropsychiatric disorders, and the human and experimental evidence supporting the pathogenic role of neuroinflammation in selected classical psychiatric disorders. Understanding how psychosocial, genetic, immunological and neurotransmitter systems interact can reveal pathogenic clues and help target new preventive and symptomatic therapies.

Cytokine targets in the brain: impact on neurotransmitters and neurocircuits

Increasing attention has been paid to the role of inflammation in a host of illnesses including neuropsychiatric disorders such as depression and anxiety. Activation of the inflammatory response leads to release of inflammatory cytokines and mobilization of immune cells both of which have been shown to access the brain and alter behavior. The mechanisms of the effects of inflammation on the brain have become an area of intensive study. Data indicate that cytokines and their signaling pathways including p38 mitogen-activated protein kinase have significant effects on the metabolism of multiple neurotransmitters such as serotonin, dopamine, and glutamate through impact on their synthesis, release, and reuptake. Cytokines also activate the kynurenine pathway, which not only depletes tryptophan, the primary amino acid precursor of serotonin, but also generates neuroactive metabolites that can significantly influence the regulation of dopamine and glutamate. Through their effects on neurotransmitter systems, cytokines impact neurocircuits in the brain including the basal ganglia and anterior cingulate cortex, leading to significant changes in motor activity and motivation as well as anxiety, arousal, and alarm. In the context of environmental challenge from the microbial world, these effects of inflammatory cytokines on the brain represent an orchestrated suite of behavioral and immune responses that subserve evolutionary priorities to shunt metabolic resources away from environmental exploration to fighting infection and wound healing, while also maintaining vigilance against attack, injury, and further pathogen exposure. Chronic activation of this innate behavioral and immune response may lead to depression and anxiety disorders in vulnerable individuals.