Inflammatory activation and cholinergic anti-inflammatory system in eating disorders

Elevated interleukin-6 in women with binge-eating spectrum disorders

OBJECTIVE

Binge-eating spectrum disorders (BESD) involve large eating episodes accompanied by a sense of loss of control that occur in individuals with body weights spanning the full body mass index (BMI) spectrum. While research links BESD with peripheral inflammation, this literature is limited by underpowered studies and a failure to control for confounding variables that could promote inflammation independent of dysregulated eating, specifically elevated body adiposity and depression. Our study examined plasma interleukin-6 (IL-6), a marker of peripheral inflammation, in a sample of women with BESD and non-eating disorder controls, controlling for BMI, body adiposity, and depression.

METHOD

Participants (N = 94) included women with BESD (n = 73) or no eating disorder (n = 21) who completed structured clinical interviews in a larger study, selected to represent BMI categories ranging from underweight to obese in both groups. Fasting blood samples were processed for plasma IL-6 concentration via enzyme-linked immunosorbent assays. In addition to assessing group differences in plasma IL-6, exploratory analyses examined associations between IL-6 and biological and clinical markers of BESD.

RESULTS

Significantly elevated plasma IL-6 was found in women with BESD, relative to controls, that was not accounted for by BMI, adiposity, or depression. Plasma IL-6 was positively correlated with plasma leptin concentration, clinical assessments of eating disorder severity, and participants' largest self-reported eating episode.

DISCUSSION

Peripheral inflammation is specifically linked to presence of dysregulated eating independently from weight, adiposity, and depression in BESD. Future research should probe the potential role of neuroinflammation in altered eating behavior.

PUBLIC SIGNIFICANCE

This study provides the first demonstration that inflammation, characterized by elevated plasma IL-6 concentration, is uniquely associated with dysregulated eating in a transdiagnostic group of individuals with BESD. A better understanding of whether immune factors contribute to dysregulated eating could help identify novel biological targets for intervention.

Inflammatory profiles in women with eating disorder: Linking inflammatory biomarkers to clinical phenotypes

INTRODUCTION

Eating disorders (ED) represent a group of very complex and serious diagnoses characterized by emotional dysregulation and impulsivity. New approaches are necessary to achieve effective diagnosis and treatments. Shifting biomarker research away from the constraints of diagnostic categories may effectively contribute to a dimensional differentiation across disorders according to neurobiology (e.g., inflammatory biomarkers). Thus, the aim of our study was to identify inflammatory profiles in patients with ED.

METHODS

A sample of 100 women with an ED (23.4 ± 8.55 years) and 59 healthy controls (HC) (20.22 ± 4.18 years) was used. K-means cluster analysis was followed to identify inflammatory clusters considering seven blood biomarkers (iNOS, TNFα, COX2, p38, ERK, TBARS and PPARγ). Moreover, a wide assessment of clinical features was conducted.

RESULTS

Two distinct clusters were identified. Cluster 1 patients were characterized by higher inflammatory levels of TNF-α, COX2, p38, and ERK, and had more restrictive anorexia diagnosis than cluster 2. Cluster 2 participants showed higher inflammatory levels of iNOS and were older than cluster 1 and controls and had lower BMI than HC. In addition, they had higher levels of bulimic symptoms than those from the cluster 1 and HC, and higher impulsivity than HC. All ED patients (regardless of cluster) showed higher ED symptoms and more trauma than HC.

CONCLUSIONS

Our study revealed that inflammatory dysfunction may be linked with clinical endophenotypes in ED, one more restrictive (cluster 1) with an inflammation/oxidative endophenotype more cytokine and MAPK/ERK mediated, and the other more impulsive, with more bulimic symptoms (cluster 2) with NO free radical high output source iNOS. Trauma seems to be a vulnerability factor for both endophenotypes.

Oxidative stress and inflammatory pathways in female eating disorders and borderline personality disorders with emotional dysregulation as linking factors with impulsivity and trauma

BACKGROUND

Borderline personality disorder (BPD) and eating disorders (ED) are both disorders with emotional dysregulation that may share some similar biological underpinnings, leading to oxidative/inflammatory alterations. Unfortunately, to date, no studies have assessed the relationship between clinical features, inflammatory alterations and childhood trauma across these disorders. Our aim was to identify the potential common and disorder-specific inflammatory pathways and examine possible associations between these dysregulated pathways and the clinical features.

METHODS

We studied a sample of 108 women (m = 27.17 years; sd = 7.64), divided into four groups: 23 patients with a restrictive ED (ED-R), 23 patients with a bingeeating/ purging ED (ED-P) and 26 patients with BPD; whereas the control group included 23 healthy subjects. Several inflammatory/oxidative parameters: tumor necrosis factor alpha (TNFα), Thiobarbituric Acid Reactive Substances (TBARS), inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX2), p38 mitogenactivated protein kinases, ERK mitogen-activated protein kinases and c-Jun NH2- terminal kinase (JNK), and some antiinflammatory antioxidant elements: glutathione peroxidase (GPx), superoxide dismutase (SOD), catalase (CAT), Kelch-like ECHassociated protein (Keap1) were determined in plasma or peripheral blood mononuclear cells. Furthermore, clinical, impulsivity, trauma and eating behavior questionnaires were administered.

RESULTS

Three main inflammatory/oxidative components were extracted using principal component analysis (59.19 % of biomarker variance explained). Disorder-specific dysfunction in the inflammatory and oxidative pathways in patients with BPD and ED were revealed by means of relationships with specific principal components (p < .01). BPD patients showed higher levels of a component featured by elevated levels of JNK and lower of GPx and SOD. ED-R and impulsivity were associated with a component featured by the activation of ERK and negative influence of Keap1. The component featured by the suppression of catalase and COX2 was associated with both ED subtypes and trauma exposure.

CONCLUSION

Several risk factors such as trauma, impulsivity and eating disorder symptoms were transdiagnostically associated with some inflammatory alterations regardless of diagnosis. These findings suggest that the clinical profile comprising trauma exposure and an emotional dysregulation disorder might constitute a specific endophenotype highly linked with inflammatory alterations.

Dysfunction of Inflammatory Pathways and Their Relationship With Psychological Factors in Adult Female Patients With Eating Disorders

The attempts to clarify the origin of eating disorders (ED) have not been completely successful and their etiopathogenesis remains unknown. Current research shows an activation of the immune response in neuropsychiatric diseases, including ED. We aimed to investigate immune response parameters in patients with ED and to identify psychological factors influencing the inflammatory response. The relationship between inflammation markers and impulsivity and affective symptomatology was explored as well. Thirty-four adult female patients with current diagnosis of ED, none of them under psychopharmacological treatment (excluding benzodiazepines), were included in this study. Patients were compared with a healthy control group of fifteen adult females. The levels of inflammatory markers and indicators of oxidative/nitrosative stress were evaluated in plasma and/or in peripheral blood mononuclear cells (PBMCs). Subjects were assessed by means of different ED evaluation tools. Additionally, the Barratt Impulsiveness Scale, the Montgomery-Asberg Depression Rating Scale and the Hamilton Anxiety Rating Scale were also employed. Patients with ED shown increased plasma levels of the pro-inflammatory nuclear factor kappa B (NFκB) and the cytokine tumor necrosis factor-alpha (TNF-α), among other factors and an increment in the oxidative/nitrosative stress as well as increased glucocorticoid receptor (GR) expression levels in their PBMCs. Moreover, the inflammatory prostaglandin E₂ (PGE₂) correlated with impulsiveness and the anti-inflammatory prostaglandin J₂ (15d-PGJ₂) correlated with depressive symptomatology. Our results point towards a relationship between the immune response and impulsiveness and between the immune response and depressive symptomatology in female adult patients with ED.

Low levels of proinflammatory cytokines in a transdiagnostic sample of young male and female early onset eating disorders without any previous treatment: A case control study

Growing interest exists in the association of the immune system and its role in the development and maintenance of eating disorders (ED). Current evidence suggests that serum cytokine levels seem to be elevated in females with anorexia nervosa (AN). However, less is known in bulimia nervosa (BN) and other specified feeding and eating disorders (OSFED), specially in males. We aimed to perform a case-control study in a sample of forty eight young patients (38 females and 10 males) with early diagnosis of AN, BN or OSFED and without any previous treatment, compared with twenty nine healthy controls (19 females and 10 males) matched by age, sex and socioeconomic status. We evaluated eating-related psychopathology and depressive symptoms and measured serum concentration of proinflammatory cytokines IL-1β, IL-6, and TNF-α and anti-inflammatory cytokine IL-10. Contrary to expectations, levels of IL-1β and IL-6 were significantly lower in ED patients, compared with healthy controls. Comparing the different groups of females, we found elevated levels of IL-10 among ED patients therefore supporting the idea of an immunosuppressive status in the early stages. This could indicate that early onset patients without any previous treatment could remain in a reward-dependent state with a lower immune response.

Inflammatory dysregulation in women with an eating disorder: Relationships with altered emotional reactivity

BACKGROUND

Some studies suggest that inflammatory signaling dysregulation may contribute to eating disorder (ED) pathophysiology. However, little is known about the influence of inflammatory response on altered processes seen among patients with ED, such as emotional processing and reactivity.

OBJECTIVES

The objectives were: (a) to investigate the systemic inflammatory response in ED women; and (b) to analyze the role of inflammatory markers in emotional reactivity.

METHOD

Concentrations of several intercellular and intracellular inflammatory mediators (cytokines, prostaglandin by-products and enzymes, TBARS, and MAPK proteins) were quantified in plasma and PBMCs from 68 women with an ED (m = 22.01 years, SD = 9.15) and 35 healthy controls (m = 18.54 years, SD = 4.21). Moreover, emotional reactivity to affective pictures (those without either food or thinness content) was studied using the adult (>18 years old) sample (n = 41).

RESULTS

Between-group differences were revealed for most markers (TNF-α, PGE₂ , COX2, and ratio of activated MAPK proteins), pointing to increased inflammatory response in patients (p < .01). Women with ED showed heightened emotional reactivity, regardless of picture valence. Principal components derived from inflammatory markers showed an explanatory loading on patient's emotional reaction, in terms of valence and arousal.

CONCLUSION

This study corroborates the altered systemic inflammatory response in patients with ED. The inflammatory dysregulation may contribute to ED phenotype, as seen by its relationship with heightened emotional reactivity, even though the inflammatory markers were not evaluated throughout the emotional reactivity protocol.

Evidence of upregulation of the cholinergic anti-inflammatory pathway in late-life depression

BACKGROUND

Decreased cholinergic tone associated with increased proinflammatory cytokines has been observed in several human diseases associated with low-grade inflammation. We examined if this attenuated cholinergic anti-inflammatory pathway (CAP) mechanism contributed to increased neuroinflammation observed in depression.

METHODS

We measured cerebrospinal fluid (CSF) cholinergic markers (AChE and BChE activities) in 28 individuals with longstanding late-life major depression (LLMD) and 19 controls and their relationship to central and peripheral levels of pro-inflammatory cytokines (IL-6 and IL-8). Additionally, we examined if these cholinergic indices were related to CSF markers of microglial activation and neuroinflammation (sTREM2 and complement C3).

RESULTS

Compared with controls, LLMD patients had a significant reduction in CSF BChE levels. Lower CSF BChE and AChE activities were associated with lower CSF markers of microglial and neuroinflammation (sTREM2 and C3). In addition, in LLMD patients we found an inverse relationship between peripheral marker of inflammation (plasma IL-6) and CSF BChE and AChE levels.

CONCLUSIONS

Our results suggest an upregulation of the CAP mechanism in LLMD with an elevation in peripheral markers of inflammation and concomitant reduction in markers of glial activation associated with a higher cholinergic tone. Future studies should confirm these findings in a larger sample including individuals with acute and more severe depressive episodes and across all ages.

Childhood trauma determines different clinical and biological manifestations in patients with eating disorders

PURPOSE

There is a significant relationship between childhood trauma and the development of an eating disorder in adolescence or adulthood, possibly influenced by circulating levels of inflammatory parameters. The main objective is to identify and describe a subgroup of patients with eating disorders and a history of trauma in childhood or adolescence with differential clinical features.

METHODS

An observational study on a sample of 55 patients who met the diagnostic criteria for any DSM-5 eating disorder was carried out. Inflammatory parameters in white blood cells were examined. Patients underwent different assessments, including clinical and personality scales.

RESULTS

Patients with a history of trauma had higher scores in the delirious and narcissistic items of the Millon Clinical Multiaxial Inventory (MCMI-II) (p < 0.05) and a higher score in the paranoid item of the SCID-5 Personality Disorders Version (SCID-5-PD) (p < 0.05). Patients with distinguishing personality features were grouped according to the Childhood Trauma Questionnaire sexual subscale. Tumor necrosis alpha (TNF-α) showed a significant association with childhood trauma history.

CONCLUSIONS

There is a profile of patients with eating disorders who have increased activity in the inflammatory pathways that, if identified precociously, can benefit from specifically aimed interventions.

LEVEL OF EVIDENCE

Level V, observational study.

The Role of the Gut Microbiome, Immunity, and Neuroinflammation in the Pathophysiology of Eating Disorders

There is a growing recognition that both the gut microbiome and the immune system are involved in a number of psychiatric illnesses, including eating disorders. This should come as no surprise, given the important roles of diet composition, eating patterns, and daily caloric intake in modulating both biological systems. Here, we review the evidence that alterations in the gut microbiome and immune system may serve not only to maintain and exacerbate dysregulated eating behavior, characterized by caloric restriction in anorexia nervosa and binge eating in bulimia nervosa and binge eating disorder, but may also serve as biomarkers of increased risk for developing an eating disorder. We focus on studies examining gut dysbiosis, peripheral inflammation, and neuroinflammation in each of these eating disorders, and explore the available data from preclinical rodent models of anorexia and binge-like eating that may be useful in providing a better understanding of the biological mechanisms underlying eating disorders. Such knowledge is critical to developing novel, highly effective treatments for these often intractable and unremitting eating disorders.

Inflammatory and antioxidant pathway dysfunction in borderline personality disorder

INTRODUCTION

This study investigates the alteration of the inflammatory/oxidative pathway in patients with borderline personality disorder (BPD) and its relationship with clinical features of the disorder.

METHODS

49 BPD patients and 33 healthy control subjects were studied. Plasma levels of TBARS, nitrites, and the antioxidant enzymes CAT, GPx and SOD were measured. In addition, peripheral blood mononuclear cells were obtained to investigate levels of intracellular components of the inflammatory/oxidative pathway including the IκBα, NFκB, iNOS, COX2, Keap1, NQO1, and HO1. Western Blot and ELISA were used to measure protein expression. Patients were assessed for different clinical dimensions of BPD with scales for depression, anxiety, impulsivity and functioning.

RESULTS

A significant decrease of IκBα levels and a significant increase of inflammatory factors, including NFκB, COX2 and iNOS levels were found in patients. On the other hand, a significant decrease was observed for all antioxidant enzymes in patients with BPD, except for HO1. The inflammatory factor NFκB showed a significant positive correlation with impulsivity scores.

CONCLUSIONS

Patients with BPD presented an increased activation of several components of the inflammatory pathways, as well as an inhibition of the antioxidant path. These alterations appear partially correlated with the impulsivity scores in these patients.

Dysfunction of inflammatory pathways in adolescent female patients with anorexia nervosa

BACKGROUND

The pathogenesis of Eating Disorders is still unknown. However, a growing body of evidence shows that there are changes in cytokine levels and an alteration in the stress response in patients with anorexia nervosa (AN). For this reason, we decided to test whether there are differences in immune parameters involved in the regulation of the inflammatory response between female adolescents with AN and healthy adolescents.

METHODS

The sample 27 drug-naïve AN patients the study sample included 27 AN patients at a very early stage of the disease and 23 healthy controls. Plasma and peripheral blood mononuclear cells (PBMCs) were obtained for biochemical study.

RESULTS

Plasma levels of the pro-inflammatory cytokines TNF-α and IL-1β were significantly increased in patients with AN, while the levels of prostaglandins PGE₂ (proinflammatory) and 15d-PGJ₂, (anti-inflammatory) were lower compared with controls. Protein expression in PBMCs of cyclooxygenase-2 (COX-2) and the activated forms of the mitogen-activated protein kinases p38 and ERK were also increased in the AN group. Expression levels of the anti-inflammatory factor peroxisome proliferator-activated receptor gamma (PPARγ) were significantly decreased in patients. Plasma levels of lipid peroxidation markers -TBARS- were not increased in patients with AN. Components of the biochemical inflammatory response (COX-2, PGE₂, TBARS, 15d-PGJ₂, ERK, p65 NFκB) and glucocorticoid receptor -GR- expression and the scores on the impulsivity measures in the BARRATT, EDI and BITE questionnaires showed a significant correlation within the AN patients group.

CONCLUSIONS

The results for female adolescent patients with AN indicate that there is a dysfunction of intra- and intercellular inflammatory pathways characterized by higher levels of pro-inflammatory parameters in plasma and a decrease in one of the controlling cytoplasmic-nuclear pathways implicated in their modulation (i.e. PPARγ) with, at this very early stage of the disease, no effect on oxidative stress markers plasma levels. Most notably, higher severity of illness (restrictive and purging behaviour) correlated with higher levels of inflammatory markers.

Psychoneuroimmunology of mental disorders

The immune system is a key element in the organism's defence system and participates in the maintenance of homeostasis. There is growing interest in the aetiopathogenic and prognostic implications of the immune system in mental disorders, as previous studies suggest the existence of a dysregulation of the immune response and a pro-inflammatory state in patients with mental disorders, as well as an increased prevalence of neuropsychiatric symptoms in patients suffering from autoimmune diseases or receiving immune treatments. This study aims to conduct a narrative review of the scientific literature on the role of Psychoneuroimmunology in mental disorders, with special focus on diagnostic, prognostic and therapeutic issues. The development of this body of knowledge may bring in the future important advances in the vulnerability, aetiopathogenic mechanisms, diagnosis and treatment of some mental disorders.

Increased use of antimicrobial medication in bulimia nervosa and binge-eating disorder prior to the eating disorder treatment

OBJECTIVE

We examined the use of antimicrobial medication as a proxy for infections in large patient cohort treated for binge-eating disorder (BED), bulimia nervosa (BN), and anorexia nervosa (AN) over the five-year period preceding eating disorder treatment.

METHOD

Patients (N = 1592) at the Eating Disorder Unit of Helsinki University Central Hospital between 2000 and 2010 were compared with matched general population controls (N = 6368). The study population was linked to the prescription data of antibacterial, antifungal and antiviral medication from the Register on Reimbursed Prescription Medicine. Data were analyzed using regression models.

RESULTS

Individuals with BN and BED had received more often antimicrobial medication prescriptions compared to their controls (OR: 1.7, 95% CI: 1.3-2.1; OR: 2.6, 95% CI: 1.4-4.6, respectively), while no significant difference emerged in AN (OR: 0.9, 95% CI: 0.7-1.0, p = 0.10). Of the main drug categories, the respective pattern was seen in antibacterial and antifungal medication, while increased use for antivirals appeared only in BN (OR: 1.6, 95% CI: 1.1-2.3). Measured with the mean number of prescriptions or mean Defined Daily Doses per individual, patients with BN, BED and males with AN had also higher total antimicrobial medication use.

DISCUSSION

Indicating increased infections, we found elevated use of antimicrobial medication in BN, BED and in males with AN. Infections may be consequence of hyperglycemia, weight gain, or dysregulation of intestinal microbiota associated with core eating disorder behaviors. Or the other way round; changes in intestinal microbiota due to infections, inflammation, or antibacterial medications might contribute to eating disorders in multiple ways. © 2016 Wiley Periodicals, Inc. (Int J Eat Disord 2016; 49:542-552).

Meta-Analysis of Cytokines and Chemokines in Suicidality: Distinguishing Suicidal Versus Nonsuicidal Patients

BACKGROUND

Major psychiatric disorders are associated with inflammation. Aberrant cytokine and chemokine levels have been associated with psychiatric disorders and suicidal behavior. We performed a meta-analysis of cytokine and chemokine levels in patients with versus without suicidality and patients with suicidality versus healthy controls.

METHODS

We identified articles by searching MEDLINE, PsycINFO, and Thomson Reuters Web of Knowledge databases and the reference lists of identified studies.

RESULTS

Study inclusion criteria were met by 18 studies comprising 583 patients with suicidality, 315 patients without suicidality, and 845 healthy control subjects. Levels of interleukin (IL)-1β and IL-6 were significantly increased in blood and postmortem brain samples of patients with suicidality compared with both patients without suicidality and healthy control subjects (p < .05 for each). In vitro IL-2 production by peripheral blood mononuclear cells was significantly decreased in patients with suicidality compared with both patients without suicidality and healthy controls (p < .01 for each). Cerebrospinal fluid levels of IL-8 were significantly decreased in patients with suicidality versus control subjects (p < .05).

CONCLUSIONS

We found evidence for aberrant cytokine levels in blood, cerebrospinal fluid, and postmortem brain samples of patients with suicidality. Levels of IL-1β and IL-6 were most robustly associated with suicidality, and these cytokines may help distinguish suicidal from nonsuicidal patients. Rigorously designed longitudinal studies are needed to evaluate these associations further.