The role of tumor necrosis factor-alpha in the pathogenesis of anorexia and bulimia nervosa, cancer cachexia and obesity

Pro-inflammatory cytokine alterations in recent onset anorexia nervosa adolescent female patients before and after 6 months of integrated therapy: A case-control study

Anorexia nervosa (AN) is a complex disorder affecting mainly, but not only, teenagers. Researchers agree that AN is deeply associated with a pro-inflammatory state following an impaired immune system, resulting from altered levels of cytokines such as IL-1β and TNF-α, also impacted by the frequent depressive states. Thus, this case-control study aimed to evaluate the relationship between patients suffering from AN undergoing specialized eating disorder treatment for AN and pro-inflammatory cytokines. To reach our purpose, we assessed eating-related psychopathology and depressive symptoms and measured serum concentration of pro-inflammatory cytokines IL-1β, IL-6, IL-8, and TNF-α before and after 6 months of integrated therapy (which included psychopharmacotherapy, psychotherapy, and nutritional treatment), to define whether selected pro-inflammatory cytokines could be considered a pathophysiological marker of the disorder. A sample of 16 young female patients with early diagnosis of AN, and without any previous treatment, and 22 healthy controls matched by age, sex, and socioeconomic status were enrolled. After 6 months of integrated therapy, a significant decrease of all selected pro-inflammatory cytokines was detected. In addition, an improvement in the anxiety-depressant aspects was also noted. In conclusion, the results obtained suggest that pro-inflammatory cytokines are indeed related to the pathophysiology of AN. However, further investigations, involving larger samples of patients with distinct subtypes of AN, are essential to confirm the current findings.

Anorexia Nervosa in vivo cytokine production: a systematic review

INTRODUCTION

The underlying psychobiology that contributes to Anorexia Nervosa (AN) onset and disease progression remains unclear. New research is emerging suggesting a possible link between inflammation and a variety of mental illnesses. Alterations of cytokines may play a role in the pathogenesis of AN. Some studies have found differences in the cytokine profile of those with AN compared to healthy controls, but results are heterogeneous. The aim of this work was to systematically review existing studies investigating in-vivo cytokine production in those with AN before and after weight restoration compared to controls.

METHODS

A comprehensive literature search of four electronic databases (PubMed, PsychInfo, EMBASE and CINAH) was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines to identify human in-vivo studies investigating the relationship between AN and cytokine production. Data extracted from included studies related to population characteristics (e.g. age, gender, mean mBMI/%IBW), cytokine measurement and relevant findings. Confounding factors (e.g. smoking status, co-morbid mental illness, menstruation status) were also collected.

RESULTS

36 studies were eligible for this systematic review of which the majority were conducted in Europe (77.8%) and involved female subjects (97.2%). Those with AN ranged in age from 13 to 47 years and had an illness duration of 3 months to 24 years. 15 candidate cytokines and 3 receptors were identified (TNF-alpha, IL-6, IL-1B, CRP, IL-2, IL-7, IL-10, IFN-γ, TNF-R2, IL-1 α, IL-15, TNF-R1, IL-17, IL-18, TGF-B1, IL-12, IL-6R and TGF-B2) exploring in-vivo levels in patients with AN and comparing to controls. TNF-alpha and IL-6 were the most extensively studied with IL-6 being significantly elevated in 4 out of 8 (50%) of longitudinal studies when comparing AN patients at baseline compared to post weight restoration. Following weight restoration, there was no difference in IL-6 levels when comparing to HC in 7 of 8 (87.5%) longitudinal studies examined.

CONCLUSIONS

The most promising cytokine potentially involved in the pathogenesis of AN appears to be IL-6, and possibly TNF-alpha pathways. The heterogeneity of clinical and methodology factors impedes the generalizability of results. Future studies may wish to address these methodological shortcomings as alterations in cytokine levels in AN could act as therapeutic targets assisting with weight restoration and psychopathology and may offer diagnostic potential.

ZAG (Zinc-Alpha 2 Glycoprotein) Serum Levels in Girls with Anorexia Nervosa

The objectives of the study were: (1) the evaluation of the blood serum concentration of ZAG (Zinc-alpha 2 Glycoprotein) in girls with anorexia nervosa, as well as in girls with simple obesity and healthy girls; and (2) the valuation of the relationship between the blood level of ZAG and the duration of AN and anthropometric parameters, parameters of the lipid and carbohydrate metabolism, thyroid hormones, and cortisol in the blood in all study subjects.

MATERIALS AND METHODS

The study covered 87 girls (aged 11-17.9 years). The studied group (AN) contained 30 girls suffering from anorexia nervosa, and the control groups contained 30 healthy girls (H) and 27 girls with simple obesity (OB), respectively.

RESULTS

The mean concentration of ZAG in the blood serum in the AN group was significantly higher than in the OB and H groups. Accumulatively, the level of ZAG in the entire studied group correlated negatively with the parameters of their nutritional status. The mean concentrations of ZAG in the entire group correlated positively with the concentrations of HDL and cortisol and negatively with insulin, HOMA-IR, triglycerides, and hsCRP.

CONCLUSIONS

The higher blood concentrations of ZAG in girls with AN compared to healthy subjects seemed to constitute a secondary adaptation mechanism in response to the undernourishment status. ZAG blood concentration values correlated negatively with body mass, BMI, Cole's index, the level of insulin, and the HOMA-IR score, whereas they correlated positively with the level of cortisol. Increased ZAG levels in AN patients may result from increased levels of cortisol, manifesting in malfunction along the hypothalamic-pituitary-adrenal axis, which in effect can promote body weight loss.

Clinical and Peripheral Biomarkers in Female Patients Affected by Anorexia: Does the Neutrophil/Lymphocyte Ratio (NLR) Affect Severity?

Anorexia Nervosa (AN) is a disabling disorder characterized by extreme weight loss and frequent chronicization, especially in its most severe forms. This condition is associated with a pro-inflammatory state; however, the role of immunity in symptom severity remains unclear. Total cholesterol, white blood cells, neutrophils, lymphocytes, platelets, iron, folate, vitamin D and B12 were dosed in 84 female AN outpatients. Mildly severe (Body Mass Index-BMI ≥ 17) versus severe (BMI < 17) patients were compared using one-way ANOVAs or χ² tests. A binary logistic regression model was run to investigate the potential association between demographic/clinical variables or biochemical markers and the severity of AN. Patients with severe anorexia (compared to mild forms) were older (F = 5.33; p = 0.02), engaged in more frequent substance misuse (χ² = 3.75; OR = 3.86; p = 0.05) and had a lower NLR (F = 4.12; p = 0.05). Only a lower NLR was predictive of severe manifestations of AN (OR = 0.007; p = 0.031). Overall, our study suggests that immune alterations may be predictive of AN severity. In more severe forms of AN, the response of the adaptive immunity is preserved, while the activation of the innate immunity may be reduced. Further studies with larger samples and a wider panel of biochemical markers are needed to confirm the present results.

Anorexia nervosa and autoimmune comorbidities: A bidirectional route?

Immunological dysfunctions in eating disorders have recently gained increasing scientific attention. Furthermore, the reciprocal association between anorexia and autoimmune diseases is of particular interest and suggests a role of autoimmunity in the pathogenesis of eating disorders. Anorexia nervosa (AN) and autoimmune diseases are linked by a bidirectional relationship based on common immunopathological mechanisms. In this review, in addition to reporting the numerous cases described in which autoimmune disorders are associated with anorexia or vice versa, we summarize the many aspects of this relationship between the immune system (IS) and AN. We describe how the microbiota affects the IS, disrupts gut-brain communication, and possibly triggers eating disorders. We also describe the shared immunological pathways of autoimmune and eating disorders and in particular the occurrence of disrupted T cell tolerance and autoantibodies in AN. The described observations represent the starting point for possible, future research directions.

Expression of immune-related proteins and their association with neuropeptides in adolescent patients with anorexia nervosa

Anorexia nervosa (AN) is a metabo-psychiatric disorder where alterations of cytokines, neuropeptides, neurotransmitters, and the interactions between these factors can play an important role. Thus, the primary goal of the presented study was a cross-sectional analysis of immune-related proteins in patients with AN. Moreover, the correlations between these molecules and selected neuropeptides were studied. Twenty-five adolescent inpatients girls in the acute stage of a restrictive type of AN were enrolled in the study within the first year of the disease. Additionally, thirty similar in age and height controls (CG) were also assessed. The levels of 24 immune-related proteins, including cytokines, chemokines, and proteases, were measured. Moreover, selected adipocytokines, gastrointestinal hormones, and centrally produced neuropeptides levels were determined. Finally, the correlations between these molecules were analyzed. The fasting levels of CXCL1, CXCL9, FGF2, GrB, IL1, IL6, IL8, MMP8, MMP9, CTSS were statistically lower in AN than in the CG. The concentrations of many immune-related proteins remain unchanged despite their metabolic and mental condition. Moreover, significant correlations were found between leptin and CXCL1, CXCL9, GrB, IL1, IL6, and MMP8. Leptin receptors were correlated with GrB, while resistin was associated with MMP9. Our findings suggest that the initial stage of restrictive AN among adolescents within the first year of the disease is not connected with a pro-inflammatory state. Some immune-related protein changes may be associated with altered neuropeptides, primarily leptin, its receptors, and resistin. Future research should clarify which changes are primary and secondary to weight loss and whether these changes normalize with increasing weight. This would aid in understanding the complex etiopathogenesis of AN and in the search for new methods of treatment.

Longitudinal associations between circulating interleukin-6 and C-reactive protein in childhood, and eating disorders and disordered eating in adolescence

OBJECTIVE

Few studies have explored the association between inflammation and eating disorders and none used a longitudinal design. We investigated the association between serum-levels of interleukin 6 (IL-6) and C-reactive protein (CRP) measured in childhood and eating disorders and related behaviours and cognitions in adolescence in a large general population sample.

METHODS

We used data from the Avon Longitudinal Study of Parents and Children (ALSPAC). Our exposures were thirds of IL6 and CRP derived from serum measurements taken at age nine years, and outcomes were eating disorder diagnoses and self-reported disordered eating behaviours at ages 14, 16, and 18 years. We used univariable and multivariable multilevel logistic regression models adjusting for a number of potential confounders, including sex, fat mass, and pre-existing mental health difficulties.

RESULTS

Our sample included 3480 children. Those in the top third of CRP had lower odds of binge eating (odds ratio(OR):0.62, 95% confidence interval (CI):0.39,1.00,p "equals" 0.05) and fasting (OR:0.63, 95% CI:0.38,1.07,p "equals" 0.09) after adjustment for confounders. We also observed weak associations of comparable magnitude for purging, anorexia nervosa, and bulimia nervosa. We did not find any associations between levels of IL6 and any of the outcomes under study.

CONCLUSIONS

There was little evidence of an association between CRP and IL-6 and adolescent eating disorder outcomes. The inverse association observed between CRP and binge eating was unexpected, so caution is needed when interpreting it. One possible explanation is that higher CRP levels could have a protective role for disordered eating by affecting appetitive traits.

Impact of TNF-α Inhibitors on Body Weight and BMI: A Systematic Review and Meta-Analysis

Objective

The aim of this systematic review and meta-analysis of longitudinal studies was to ascertain to effects of TNF-α inhibitor therapy on body weight and BMI.

Methods

Three databases (PubMed, OVID, and EMBASE) were systematically searched from inception to August 2018. We identified prospective, retrospective, and randomized controlled studies in adults with immune-mediated inflammatory diseases treated with TNF-α inhibitors based on pre-specified inclusion criteria. A random-effects model was used to estimate standardised mean change (SMCC).

Results

Twenty-six longitudinal studies with a total of 1,245 participants were included in the meta-analysis. We found evidence for a small increase in body weight (SMCC = 0.24, p = .0006, 95% CI [0.10, 0.37]) and in BMI (SMCC = 0.26, p < .0001, 95% CI [0.13, 0.39]). On average, patients gained 0.90kg (SD = 5.13) under infliximab, 2.34kg (D = 5.65) under etanercept and 2.27kg (SD = 4.69) during treatment with adalimumab within the duration of the respective studies (4–104 weeks).

Conclusion

Our results yield further support the for the view that TNF-α inhibitors increase body weight and BMI as a potential side effect. Modulating cytokine signaling could be a future therapeutic mechanism to treat disorders associated with weight changes such as anorexia nervosa.

A systematic review of in vitro cytokine production in eating disorders

BACKGROUND

Eating disorders (EDs) have been associated with alterations in cytokine concentrations and production. This review examines whether in vitro cytokine production (i) is altered in people with EDs compared to healthy participants; and (ii) changes in response to treatment?

METHODS

Using PRISMA guidelines, we systematically reviewed articles reporting group comparisons or longitudinal assessments of spontaneous and/or stimulated cytokine production in vitro in people with EDs.

RESULTS

Twelve studies were included. Cross-sectional results were mixed in anorexia nervosa. Only one study measured cytokine production in bulimia nervosa. Two longitudinal studies showed that daily yoghurt consumption increases phytohemagglutinin-stimulated interferon-γ production in anorexia nervosa.

CONCLUSION

The mixed results could be accounted for by variations in experimental design. Our findings suggest that cytokine production could possibly be modulated through dietary interventions. However, due to the methodological heterogeneity and shortcomings of the included studies, it seems unreasonable to draw further conclusions.

Brain-Behavior-Immune Interaction: Serum Cytokines and Growth Factors in Patients with Eating Disorders at Extremes of the Body Mass Index (BMI) Spectrum

Alterations of the immune system are known in eating disorders (EDs), however the importance of cytokine balance in this context has not been clarified. We compared cytokines and growth factors at opposite ends of BMI ranges, in 90 patients classified in relation to BMI, depressive and EDs comorbidities. Serum concentrations of interleukin (IL)-1α, IL-1β, IL-2, IL-4, IL-6, IL-8, IL-10, interferon-gamma (IFN-γ), tumor necrosis factor-alpha (TNF-α), monocyte chemoattractant protein-1 (MCP-1), vascular endothelial growth factor (VEGF), and epidermal growth factor (EGF) were determined by a biochip analyzer (Randox Labs). Differences were calculated through ANOVA. Possible predictors of higher cytokine levels were evaluated through regression analysis. IL-1α, IL-10, EGF, and IFN-γ were altered individuals with anorexia nervosa (AN) and binge eating disorder (BED). Night-eating was associated with IL-8 and EGF levels, IL-10 concentrations with post-dinner eating and negatively with sweet-eating, long fasting with higher IFN-γ levels. IL-2 increase was not linked to EDs, but to the interaction of depression and BMI. Altogether, for the first time, IL-1α, IL-10, EGF, and IFN-γ were shown to differ between AN and HCs, and between AN and individuals with obesity with or without BED. Only IL-2 was influenced by depression. Dysfunctional eating behaviors predicted abnormal concentrations of IL-10, EGF, IL-8 and IFN-γ.

Ovotransferrin enhances intestinal immune response in cyclophosphamide-induced immunosuppressed mice

Ovotransferrin (OVT), a glycoprotein from avian egg, which has a variety of biological activities and immunomodulatory effects. The purpose of this research was to demonstrate the effect of OVT on intestinal immunomodulatory function which used a mouse model of cyclophosphamide (CP) induced intestinal immunosuppression and injury by intraperitoneal injection of 80 mg/kg. Effects of OVT on intestinal immunomodulatory function in CP-induced immunosuppression mice were detected by flow cytometry, real-time quantitative polymerase chain reaction, enzyme-linked immunosorbent assay, and western blot. Results showed that OVT effectively increased the major histocompatibility complex class II (MHC-II) and cluster of differentiation 83 (CD83) levels to enhance intestinal dendritic cells (DCs) maturation and promoted the expression of cytokines and gene of tumor necrosis factor alpha (TNF-α), interferon-γ (IFN-γ), interleukin-4 (IL-4) and interleukin-10 (IL-10). Furthermore, the imbalance ratio of the Th1 and Th2 in the intestine was regulated to produce an immune response and the expression of immunoglobulin A (IgA) and secretory immunoglobulin A (sIgA) were increased to promote humoral immunity by OVT-treated. Meanwhile, cyclophosphamide treatment induces activation of p38 MAPK, c-Jun N-terminal kinase (JNK) and extracellular signal-regulated kinase (ERK) to causes intestinal damage and blockage of p38 MAPK, JNK and ERK activation contributed to the effect of OVT on the repair of intestinal damage. These results indicated that OVT may have immunomodulatory function and could be potential functional factor to regulate body intestinal immunity.

Can neuroimmune mechanisms explain the link between ultraviolet light (UV) exposure and addictive behavior?

High ultraviolet (UV) light exposure on the skin acts as a reinforcing stimulus, increasing sun-seeking behavior and even addiction-like sun seeking behavior. However, the physiological mechanisms that underlie this process remain to be defined. Here, we propose a novel hypothesis that neuroimmune signaling, arising from inflammatory responses in UV-damaged skin cells, causes potentiated signaling within the cortico-mesolimbic pathway, leading to increased sun-seeking behaviors. This hypothesized UV-induced, skin-to-brain signaling depends upon cell stress signals, termed alarmins, reaching the circulation, thereby triggering the activation of innate immune receptors, such as toll-like receptors (TLRs). This innate immune response is hypothesized to occur both peripherally and centrally, with the downstream signaling from TLR activation affecting both the endogenous opioid system and the mesolimbic dopamine pathway. As both neurotransmitter systems play a key role in the development of addiction behaviors through their actions at key brain regions, such as the nucleus accumbens (NAc), we hypothesize a novel connection between UV-induced inflammation and the activation of pathways that contribute to the development of addiction. This paper is a review of the existing literature to examine the evidence which suggests that chronic sun tanning resembles a behavioral addiction and proposes a novel pathway by which persistent sun-seeking behavior could affect brain neurochemistry in a manner similar to that of repeated drug use.

A meta-analysis of cytokine concentrations in eating disorders

Cytokines are signalling molecules, which play an important role in both immune system function and brain development and function, and subsequently mental states and behaviour. Cytokines have been implicated in eating disorders (EDs) due to their role in psychological health, body weight and appetite regulation. This meta-analysis examined cross-sectional and longitudinal studies measuring concentrations of cytokines in individuals with EDs. Using PRISMA guidelines, we systematically reviewed relevant articles in PubMed, Web of Science, and MEDLINE. Random-effects meta-analyses were conducted for interleukin (IL)-1β, IL-6, transforming growth factor (TGF)-β, and tumor necrosis factor (TNF)-α, independently, firstly with all EDs combined and then stratified by ED diagnosis. Twenty-five studies were included: serum/plasma cytokine concentrations were measured in people with anorexia nervosa (AN) in 23 studies and bulimia nervosa (BN) in 4 studies. TNF-α and IL-6 were elevated in ED participants compared to healthy controls (HCs). Specifically, this pattern was seen only when comparing AN participants to HCs. Concentrations of these cytokines did not differ between people with BN and HCs. IL-1β and TGF-β did not differ between HCs and any ED group. Therefore, AN seems to be associated with elevated concentrations of TNF-α and IL-6. Considering the role of cytokines in appetite, mood regulation, and anxiety, these pro-inflammatory cytokines could be a potential future drug target to help people with AN, not only with weight gain, but also with various coexisting psychological problems. Future studies should consider confounding factors that affect cytokine concentrations and report ED-relevant clinical characteristics.

The adiponectin promoter activator NP-1 induces high levels of circulating TNFα and weight loss in obese (fa/fa) Zucker rats

Chronic NP-1 administration reduces body weight and hepatic steatosis despite induction of tolerance in adiponectin gene transcription with respect to the acute actions of this drug. This study explored the hypothesis that NP-1 could exert these effects through mechanisms independent of adiponectin. To this aim, we took advantage of the Zucker (fa/fa) rat model, which exhibits obesity, fatty liver and elevated leptin and adiponectin levels. Body weight and food intake were reduced after chronic NP-1 treatment. Plasma TNFα concentrations were elevated but no increase in adiponectin was found. Even so, NP-1 ameliorated fatty liver and corrected dyslipidemia by mechanisms probably associated with reduced feeding, transcription of Cpt1 and down-regulation of Hmgcr-CoA expression. In brown fat tissue NP-1 increased Dnmt1 (inhibitor of Adipoq) while it reduced Ucp1 expression and heat production, which excludes thermogenesis as a mechanism of the NP-1 slimming effect. The anti-obesity action of chronic NP-1 administration might be mediated by TNFα, which is known to have anorectic actions in the hypothalamus and to regulate both Dmnt1 and Ucp1 expression in adipose tissues. This finding opens up the possibility of using NP-1-mediated TNFα-induced weight loss as an innovative treatment of complicated obesity under strict pharmacologic control.

Immune disorders in anorexia

Anorexia nervosa is a disease involving eating disorders. It mainly affects young people, especially teenage women. The disease is often latent and occurs in many sub-clinical and partial forms. Approximately from 0.3% to 1% of the population suffers from anorexia. It has been shown that patients with anorexia develop neurotransmitter-related disorders, leading to uncontrolled changes in the immune and endocrine systems. Interactions between cytokines, neuropeptides, and neurotransmitters play an important role in disease development. Significant malnutrition induces disorders and alterations in T-cell populations. The cellular response in patients with anorexia nervosa has been shown to be normal, although opinions on this issue are controversial. Laboratory studies on neutrophils in anorexia patients showed decreased adhesion and reduced bactericidal and cell activities. Despite such unfavourable results, patients with anorexia are resistant to infections, which are very rare in this group. Glutamine improves the performance of the human immune system. The administration of glutamine to anorexia patients, as a supplement to parenteral nutrition, has resulted in significant improvements in immune system parameters. The results of previous studies on the causes and risk factors in the development of anorexia nervosa are still ambiguous. One can hope that the differences and similarities between patients with anorexia nervosa and those with other forms of protein-calorie malnutrition may be helpful in determining the relationship between nutritional status and body defences and susceptibility to infection, and can help to broaden the knowledge about the aetiopathogenesis of anorexia nervosa.

Gastrointestinal comorbidities which complicate the treatment of anorexia nervosa

Patients with anorexia nervosa often voice a multitude of symptoms in regards to their gastrointestinal tract. These complaints can complicate the treatment of their eating disorder as they distract attention from the important goal of weight restoration. Moreover, the restricting of certain food groups also makes the task of weight restoration substantially more difficult, or may result in binging. Therefore a working knowledge of common gastrointestinal comorbidities, such as celiac disease, irritable bowel syndrome, inflammatory bowel disease, and gastroparesis, is useful when treating a patient who has anorexia nervosa.

Hypothalamic expression of inflammatory mediators in an animal model of binge eating

Binge eating episodes are characterized by uncontrollable, distressing eating of a large amount of highly palatable food and represent a central feature of bingeing related eating disorders. Research suggests that inflammation plays a role in the onset and maintenance of eating-related maladaptive behavior. Markers of inflammation can be selectively altered in discrete brain regions where they can directly or indirectly regulate food intake. In the present study, we measured expression levels of different components of cytokine systems (IL-1, IL-6, IL-18, TNF-α and IFN-ɣ) and related molecules (iNOS and COX2) in the preoptic and anterior-tuberal parts of the hypothalamus of a validated animal model of binge eating. In this animal model, based on the exposure to both food restriction and frustration stress, binge-like eating behavior for highly palatable food is not shown when animals are exposed to the frustration stress during the estrus phase. We found a characteristic down-regulation of the IL-18/IL-18 receptor system (with increased expression of the inhibitor of the pro-inflammatory cytokine IL-18, IL-18BP, together with a decreased expression of the binding chain of the IL-18 receptor) and a three-fold increase in the expression of iNOS specifically in the anterior-tuberal region of the hypothalamus of animals that develop a binge-like eating behavior. Differently, when food restricted animals were stressed during the estrus phase, IL-18 expression increased, while iNOS expression was not significantly affected. Considering the role of this region of the hypothalamus in controlling feeding related behavior, this can be relevant in eating disorders and obesity. Our data suggest that by targeting centrally selected inflammatory markers, we may prevent that disordered eating turns into a full blown eating disorder.

A case of anorexia nervosa with comorbid Crohn's disease: beneficial effects of anti-TNF-α therapy?

This case report describes a 26-year-old woman affected by long-lasting anorexia nervosa (AN) and Crohn's disease. Worsening of the bowel illness led to the prescription of immunosuppressive therapy (biologic infliximab for 4 months, followed by adalimumab for 6 months) and referral to our Eating Disorders Unit. Although she initially demonstrated denial of her eating disorder, in a few months she gradually improved her weight and psychopathology. Crohn's disease can worsen AN by modifying hunger and energy expenditure through the effects of TNF-α and IL-6, pro-inflammatory cytokines which moderate leptin and melanocortin signaling. Previous studies have observed the antidepressant effects of TNF antagonist in patients with treatment-resistant depression with high baseline inflammatory biomarkers. Our case report suggests that future studies are needed to clarify the existence, patterns, and extent of increased inflammatory markers in patients with AN, and whether they determine clinical features or identify subgroups of patients. Potential therapeutic significance of above issues remains to be determined.

Immune-mediated animal models of Tourette syndrome

An autoimmune diathesis has been proposed in Tourette syndrome (TS) and related neuropsychiatric disorders such as obsessive-compulsive disorder, attention-deficit/hyperactivity disorder, autism and anorexia nervosa. Environmental triggers including infection and xenobiotics are hypothesized to lead to the production of brain-directed autoantibodies in a subset of genetically susceptible individuals. Although much work has focused on Group A Streptococcus (GAS), the role of this common childhood infection remains controversial. Animal model studies based on immune and autoantibody findings in TS have demonstrated immunoglobulin (Ig) deposits and stereotypic movements and related behavioral disturbances reminiscent of TS following exposure to GAS, other activators of host anti-microbial responses, soluble immune mediators and anti-GAS or anti-neuronal antibodies. Demonstration of the ability to recreate these abnormalities through passive transfer of serum IgG from GAS-immunized mice into naïve mice and abrogation of this activity through depletion of IgG has provided compelling evidence in support of the autoimmune hypothesis. Immunologically-based animal models of TS are a potent tool for dissecting the pathogenesis of this serious neuropsychiatric syndrome.

Tumour necrosis factor alpha and oxidative stress as maintaining factors in the evolution of anorexia nervosa

OBJECTIVE

Aim of the study was to evaluate tumour necrosis factor α (TNF-α) axis and oxidative status in patients with anorexia nervosa (AN) seeking a possible correlation with both nutritional status and evolution of the disease.

SUBJECTS AND METHODS

Thirty-nine consecutive women with AN and an age-matched healthy control group were studied. Patients were 26±9 yr, with a body mass index (BMI) of 13.9±2 kg/m(2). TNF-α, its receptors TNF-R55 and TNF-R75, and oxidative status markers (selenium, ascorbic/ dehydroascorbic acid, retinol, α-tocopherol, selenium-dependent gluthatione peroxidase, reduced/oxidated gluthatione) were measured. A correlation with both nutritional indexes (body weight, BMI, albumin, prealbumin, transferrin, lymphocyte count) and disease duration was investigated. Pearson's correlation and unpaired Student's t-test were used to compare patients and controls.

RESULTS

TNF-α and oxidative status markers were significantly higher in patients than controls and TNF-α was directly related to dehydroascorbic acid (p<0.05). Both TNF-R55 and TNF-R75 were higher in patients with duration of disease longer than one year as compared to controls and patients with shorter duration. Receptors inversely correlated with BMI (p<0.05 and p<0.01) and directly with disease duration (p<0.05). Inverse correlation between disease duration and BMI was present (p<0.01).

CONCLUSIONS

The study showed activation of TNF-α axis and oxidative stress in AN patients, as well as correlation between the two systems. Due to the correlation between TNF receptors and both BMI and disease duration, a possible role of pro-inflammatory cytokines in the evolution of the eating disorder is suggested.

Eating disorders in adolescents: correlations between symptoms and central control of eating behavior

The aim of this study was to verify the relationship between eating disorders (binge eating and bulimia nervosa) and body image dissatisfaction with BMI, anorexigenic and orexigenic factors in adolescents. Thirty-two adolescents, (13 obese [BMI=36.65±5.68] and 19 non-obese [BMI=22.18±3.11]), aged between 14 and 19y, were recruited. Symptoms of eating disorders were measured by self-report questionnaires (BSQ, BITE and BES). Hormones, cytokines and neuropeptides were determined by Elisa kits (Phoenix peptide). A positive correlation was found between: leptin and BES (r=.724), BSQ (r=.705) and BITE (r=.696); BMI and BES (r=.663), BSQ (r=.525) and BITE (r=.732); the same pattern was observed to insulin and TNF-α. A negative correlation was found in α-MSH and AgRP with BES, BSQ and BITE. Blood levels of hormones and neuropeptides could be the link between obesity and eating disorders in adolescents. However, it is not clear which is the cause and which is the consequence.

Chlamydia antibodies and self-reported symptoms of oligo-amenorrhea and hirsutism: a new etiologic factor in polycystic ovary syndrome?

OBJECTIVE

To investigate whether the systemic inflammation induced by chlamydial infections might be associated with symptoms of polycystic ovary syndrome (PCOS).

DESIGN

Nested case-control study.

SETTING

A questionnaire including questions about hirsutism and oligo-amenorrhea was distributed to a representative sample of women (at age 31) from the general population-based Northern Finland Birth Cohort. Those who reported both symptoms were defined as symptomatic (n=81).

PATIENT(S)

A representative sample of women (at age 31) from the general population-based Northern Finland Birth Cohort.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

To test the presence of serum antibodies to Chlamydia pneumoniae (IgG titers ≥32) and Chlamydia trachomatis (IgG titers ≥8) by microimmunofluorescence in symptomatic and control women.

RESULT(S)

Antibodies were investigated in 79 symptomatic and 1427 control women (C. pneumoniae) and in 79 symptomatic and 425 control women (C trachomatis). C. trachomatis antibodies (odds ratio [OR], 2.4; 95% confidence interval [CI], 1.3-4.6) and C. pneumoniae antibodies (OR, 1.5; 95% CI, 1.0-2.4) were more commonly present in symptomatic women, and the simultaneous presence of elevated highly sensitive C-reactive protein levels strengthened this association.

CONCLUSION(S)

Chronic inflammation, which is associated with chlamydial infections, could contribute to the pathogenetic processes that lead to the metabolic and hormonal disorders of PCOS.

Stress and body mass index each contributes independently to tumor necrosis factor-alpha production in prepubescent Latino children

This investigation extended prior work by determining if stress and body mass index (BMI) contributed independently to tumor necrosis factor-alpha (TNF-alpha) levels among prepubescent Latino children and if sex and family history of type 2 diabetes mellitus (T2DM) modified these relationships. Data were collected in South Florida from 112 nondiabetic school-aged Hispanic children, of whom 43.8% were obese (BMI >/= 95th percentile) and 51.8% presented with a family history of T2DM. Stressful life events were assessed via parental report using a life events scale. Plasma TNF-alpha levels were determined with enzyme-linked immunosorbent assay. The relative contributions of stress and BMI with TNF-alpha levels and the potential interaction effects of sex and family history of T2DM were analyzed with multiple linear regression analyses. Stress and BMI each accounted for a significant proportion of the unique variance associated with TNF-alpha. The association between stress and TNF-alpha was not modified by sex or family history of T2DM. These findings implicate BMI and stress as independent determinants of TNF-alpha (an inflammatory cytokine and adipocytokine) among Latino children. Future investigations should examine the potential roles of exercise, nutritional status, age, and growth hormone in explicating the relationship between TNF-alpha production and psychosocial distress and risk for infection among obese children.

The hematology of anorexia nervosa

OBJECTIVE

Changes of the peripheral blood cell count in patients with anorexia nervosa (AN) are frequent. Anemia and leukopenia are observed in one-third of these patients. Examination of the bone marrow reveals in almost 50% of the patients with AN signs of bone marrow atrophy and can additionally suffer from a gelatinous bone marrow transformation.

METHOD

Published studies and investigations concerning hematological changes in patients with AN were reviewed.

RESULTS

Anemia and mild neutropenia are detectable in almost one-third of these patients, whereas thrombocytopenia is rather uncommon. The exact mechanism for these findings is still unclear, but 50% of AN-patients with hematological changes display morphological signs of partial bone marrow atrophy.

DISCUSSION

Changes of the peripheral blood cell count in patients with AN is a frequent observation but the peripheral blood cell count cannot predict the severity of bone marrow atrophy. All hematological and morphological alterations disappear completely and rapidly after sufficient refeeding.

Immunological disturbance and infectious disease in anorexia nervosa: a review

OBJECTIVE

Severely malnourished patients with anorexia nervosa (AN) are reported to show fewer symptomatic viral infections and a poorer response to bacterial infection than controls. They are also reported to show mild immune system changes, although the relevance of these to altered infection disease presentation in AN and AN pathophysiology is unknown. Thus, in this paper, we suggest a range of immune system changes that might underpin these altered responses to common pathogens, and review a number of recent infectious disease findings for their utility in explaining the pathophysiology of AN.

METHODS

A systematic review of the literature pertaining to immunity and infectious disease in AN was performed.

RESULTS

AN is associated with leucopenia, and the increased spontaneous and stimulated levels of proinflammatory cytokines [i.e. interleukin (IL)-1β, IL-6 and tumour necrosis factor α). A range of less consistent findings are also reviewed. Most of these data were not controlled for length of illness, degree of malnutrition, micronutrient or vitamin deficiencies or recent refeeding and starvation.

CONCLUSION

Cytokine disturbances have been suggested to be causally related to AN symptomatology and pathophysiology of AN, although the evidence supporting this assertion is lacking. Immune and cytokine changes in AN do, however, occur in association with a decreased incidence of symptomatic viral infection, decreased clinical response to bacterial infection leading to delayed diagnosis and increased morbidity and mortality associated with the infections.

Hostility and helper T-cells in patients with bulimia nervosa

OBJECTIVE

The study aimed to analyze the correlation between lymphocyte counts and several psychopathological variables associated with psychological instability (depression, hostility, impulsivity, self-defeating personality traits, and borderline personality symptoms) in patients with bulimia nervosa (BN).

METHOD

Sixty BN patients were assessed, using specific scales for eating pathology, general psychopathology, impulsivity, depression, and borderline personality features. Lymphocyte and lymphocyte subset counts were performed. Plasma cortisol at 8:00, before and after administration of 1 mg of dexamethasone at 23:00, was determined. The influence of body weight, and the use of tobacco, alcohol, and caffeine was controlled. The relationship between each isolated variable and the number of immune cells was analyzed. In a second step, supplementary post-hoc analysis of the variables was introduced to confirm the accuracy of the psychopathological assessment.

RESULTS

Hostility was negatively correlated with the number of helper T-cells (CD4+). Patients with high hostility had lower CD4+ cell counts and lower CD4+/CD8+ ratios. In the post-hoc control study, hostility was significantly related with other "interpersonal" items.

CONCLUSIONS

These results support the idea that hostility, as an expression of disturbed interpersonal relationships, could play a role as a modulator of immune activity in patients with BN.

Cytokine production by blood mononuclear cells from in-patients with anorexia nervosa

Although protein–energy malnutrition is a common cause of immunodeficiency, the immune function in underweight anorexia nervosa (AN) patients usually seems to be better preserved than would be expected. However, a deranged cytokine production and its consequences are currently being investigated in these patients. This study was aimed at measuring, over time, the capacity of peripheral blood mononuclear cells (PBMC) from AN in-patients to produce several cytokines involved in the regulation of immune responses. The in vitro production of interferon (IFN)-γ, interleukin (IL)-2, tumour necrosis factor (TNF)-α, IL-6 and IL-1β by phytohaemagglutinin-stimulated PBMC were assessed on forty female adolescents with AN. These measures were carried out twice, upon hospital admission and at discharge, which occurred on average after 1 month. Thirty-five control subjects were also studied. Cytokines were measured by ELISA kits. The production of TNF-α and IL-6 was lower and production of IL-1β higher in AN patients than in the control group at both time points of assessment. Refeeding for 1 month was not enough time to reverse these differences and patients still had a low body weight at discharge. IFN-γ production was lower in the patients than in control subjects only at discharge and no differences were found in IL-2 production between both groups. The results suggest that a mechanism involving modifications in the secretion pattern of proinflammatory cytokines could explain some immune function findings in underweight AN patients.

TNF-α and intPLA2 genes' polymorphism in anorexia nervosa

OBJECTIVE

The aim of this study was the assessment of -308G/A tumor necrosis factor (TNF)-α gene polymorphism and intPLA2 gene polymorphism in patients with anorexia nervosa (AN) and healthy controls.

SUBJECTS

We studied 91 non-related patients with AN and 144 healthy women (blood donors and students). The mean age of women from study group was 18.22 years (SD ± 3.13 years) and from control group was 31.71 years (SD ± 8.22).

METHODS

Gene polymorphisms were studied with the use of polymerase chain reaction-restriction fragment length polymorphism method. TNF-α gene polymorphism consists of G/A substitution in -308 promoter region. IntPLA2 gene polymorphism is related to intron 1, in which restrictive region is found and recognized by BanI enzyme.

RESULTS

We did not obtain statistically significant differences in the frequency of genotypes and alleles of -308G/A TNF-α polymorphism between the study and control groups (genotypes: P = 0.106, alleles: P = 0.076). We did analogous analysis in the restrictive and bulimic subgroups. We did not observe statistically relevant differences in the frequency of genotypes (P = 0.700) and alleles (P = 0.305). We did not obtain statistically relevant difference in the frequency of genotypes and alleles of intPLA2 gene between the study group and controls (genotypes: P = 0.300, alleles: P = 0.331). We did analogous analysis in both subgroups of AN. We did not observe statistically relevant differences in the frequency of genotypes (P = 0.344) and alleles (P = 0.230).

CONCLUSIONS

There was no statistically relevant trend for the association between TNF-α polymorphism and AN. We did not find association between studied polymorphism of intPLA2 gene and risk of AN.

Involvement of cytokines in eating disorders: a critical review of the human literature

A number of findings from clinical and animal studies indicate that pro-inflammatory cytokines may play roles in eating disorders. The measurement of pro-inflammatory cytokines (IL-1, IL-6, TNFalpha), which are known to decrease food intake, provides highly variable data from which firm conclusions cannot be drawn. In most of the longitudinal studies where pro-inflammatory cytokines have been shown to be impaired in anorexia or bulimia nervosa, a return to normal values was observed after renutrition. However these findings do not exclude the possibility that pro-inflammatory cytokines might be overproduced in specific brain areas and act locally without concomitantly increased serum or immune production. It was also pointed out that the production of the major type-1 cytokines (especially IL-2) was depressed in anorexia nervosa. It remains unclear whether this is due to undernutrition or to a specific underlying cause common to eating disorders. The impaired cytokine profile observed in eating disorders could be related to several factors including impaired nutrition, psychopathological and neuroendocrine factors. More particular attention should be devoted to the deregulation of the anti/pro-inflammatory balance. Deregulation of the cytokine network may be responsible for medical complications in eating disorder patients who are afflicted with chronic underweight.

The Role of the Immune System in Psychology and Neuroscience

The immune system and the nervous system are connected in a dynamic network that has important implications for psychology. First, if analyzed in functional terms, the immune system and the nervous system are not distinctly separated: The immune system can take part in neuronal signaling through the production of an array of transmitters and hormones, and brain cells can process and present antigen and produce immune proteins. Moreover, synapses seem to be formed between immune and neural cells in lymphoid tissue. The basis of this phenomenon may be a common evolutionary background of physiological systems that by tradition have been viewed as discrete rather than overlapping. Second, the immune system is actively involved in homeostatic regulation. Signals from immune cells can profoundly change the physiological state of the organism, with changes observed in metabolism, stress axes activity, behavior, motivation and cognition. Many of these changes have probably evolved to ease recuperation. Third, the activity in the immune system is dependent of homeostatic regulation by the neuroendocrine system in a biologically important network that is also capable of mediating psychological impact on immunity. In this review, it is argued that immunology should be ecological in nature and thereby related to psychological and neural science. Hypothetically, an ecological immunology will show cross-fertilizing properties, increasing the explanatory power of the seemingly disparate scientific disciplines involved.

Plasma concentrations of interleukin-1-beta, interleukin-6 and tumor necrosis factor-alpha, and of their soluble receptors and receptor antagonist in anorexia nervosa

Interleukin-1beta (IL-1beta), interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-alpha) induce anorexia, and multiple behavioral and biochemical alterations that mimic those of anorexia nervosa. Reports in the literature, however, contain contrasting data on the pattern of secretion of the three cytokines and on the downstream activities of their receptors and receptor antagonists in anorexia nervosa. We measured plasma concentrations of IL-1beta, IL-6, TNF-alpha, soluble IL-6 receptor (sIL-6-R), soluble TNF-alpha receptors I and II (s-TNF-alpha-R-I and II), and soluble IL-1beta receptor antagonist (s-IL-1beta-R-A) in 14 female patients with anorexia nervosa (nine restricters, five binge/purgers) and in 13 age- and sex-matched healthy control subjects to see whether the circulating cytokine concentrations and the downstream steps of cytokine activity were impaired, and if these alterations were correlated with some aspects of the disease. Concentrations of IL-1beta, IL-6, TNF-alpha, s-TNF-alpha-R-I and -II and sIL-1beta-RA in plasma did not differ significantly in patients with anorexia nervosa compared with control subjects. Concentrations of sIL-6-R were significantly lower in the patients than in the control subjects, but there were no differences between the two sub-types of anorexia nervosa. The etiopathogenetic significance of the sIL-6-R alteration is not clear, but together with recent data in the literature on cytokine function, the finding suggests that an impairment of the pro-inflammatory cytokine pathway might be involved in the development of anorexia nervosa.

Social stress in anorexia nervosa: a review of immuno-endocrine relationships

Anorexia nervosa (AN) patients have difficulty in establishing social contacts, leading to tension, anxiety and full-blown stress reactions. Stress hormones are chronically increased in AN, while immune function, which is involved in physical and psychological coping capacities, is mostly unimpaired. We examined immune function in a group of anorexics by measuring the T-lymphocyte proliferative response to stimulation with phytohemagglutinin (PHA), before and after in vivo acute administration of corticotropin-releasing hormone (CRH), to mirror a stress reaction. The responses of anorexics, before and after CRH stimulation, did not differ from those of controls. In a second group of anorexics, we measured plasma concentrations of interleukin-1 beta (IL-1 beta), interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-alpha) before and after psychopharmacological (fluoxetine, amineptine) therapy. Basal values of the cytokines were not different in patients and controls, and did not change during therapy. In the same patients, we measured basal concentrations of soluble IL-1 beta receptor antagonist (s-IL-1 beta-RA), soluble IL-6 receptor (sIL-6-R) and soluble TNF-alpha receptors I and II (sTNF-alpha-R-I and -II). S-IL-1 beta-RA and sTNF-alpha-R-I and -II levels were not different in patients and controls, while those of s-IL-6-R were lower than normal in anorexics. The normality of most of the immune parameters in our anorexics, in basal conditions, after a stressful stimulation and after pharmacological manipulation of neurotransmitters suggests that the well-known interrelation among immune, neuroendocrine and central nervous system functions is not maintained in AN, the immune system being somehow unresponsive to stimuli.

Evaluation of the correlation between serum tumor necrosis factor-alpha and relative body mass index (RBMI) in childhood

OBJECTIVE

Obesity and malnutrition are the main nutritional problems of childhood. Tumor necrosis factor-alpha (TNFalpha) is a well-known cytokine with effects on adipose tissue. In this study relative body mass index (RBMI) and serum TNFalpha levels were compared in obese and malnourished children, and hyperinsulinism was evaluated in the obese children.

SUBJECTS AND METHODS

Thirty-four children of whom 14 (9 M, 5 F) were obese, 10 (5 M, 5 F) were malnourished and 10 (4 M, 6 F) constituted the control group were evaluated. RBMI was used to define the groups according to the formula: patient's BMI/predicted BMI x 100. Mean RBMI values were 148.7 +/- 26, 77.6 +/- 4.63, and 100 +/- 8.2 in the obese, malnourished and control group, respectively. Mean ages of the obese, malnourished and control children were 9.75 +/- 2.59, 12.3 +/- 1.86 and 12.4 +/- 1.3 years, respectively.

RESULTS

Higher serum TNFalpha levels were found in the obese children (20.94 +/- 0.38 pg/ml) in comparison with the control group (2.97 +/- 0.05 pg/ml) (p <0.001). Mean TNFalpha level in the malnourished group was 2.77 +/- 0.04 pg/ml, not statistically different from the control group (p >0.05). TNFalpha concentrations of the hyperinsulinemic and normoinsulinemic obese patients were not significantly different (p >0.05).

CONCLUSION

We showed higher levels of serum TNFalpha in obese children. Increased TNFalpha levels do not always reflect hyperinsulinism. There was no difference in TNFalpha levels between the controls and the malnourished group.

Cytokines and anorexia nervosa

OBJECTIVE

Recent studies have indicated that the inflammatory cytokines could be implicated in anorexia nervosa and in its complications. To determinate the potential role of interleukins (IL-1, IL-2, IL-4, IL-6, IL-10), interferon (IFN gamma), tumor necrosis factor (TNF-alpha), and transforming growth factor (TGF-beta2) in anorexia nervosa, serum concentrations of these cytokines were measured in patients suffering from anorexia nervosa in comparison to healthy subjects.

METHOD

Twenty-nine anorexic women according to DSM-IV criteria participated in the study. The control group consisted of 20 healthy women without eating disorders, mood disorders, and immunological disorders.

RESULTS

We find that serum IL-2 and TGF-beta2 concentrations were both significantly decreased in anorexic patients, although the other cytokines did not differ significantly between the two groups.

CONCLUSION

Our results show that in patients with anorexia nervosa, there are lower levels of specific cytokines (especially IL-2 and TGF-beta2). These levels may reflect the combination of impaired nutrition and weight loss, therefore, the dysregulation of these cytokines may contribute in anorexia's complications. Follow-up studies should examine the effects of parameters such as starvation, psychopathologic factors, and psychoneuroendocrinological perturbation which could affect interplay between cytokines, neuropeptides, and neurotransmitters.

A theory of cellular-function pathology: further development of Virchow's theory of cellular pathology

A new theory of pathology is introduced. The human cell is an organism in itself. It fulfills both cell-oriented and organism-oriented functions. Impairment of either one of these functions may lead to disease. This means that a structural lesion of a cell is not a sole and necessary cause of the beginning of disease. When a cell-oriented function is impaired the cell suffers, but the overt symptoms at the organ-organism level might be absent for a very long time. This is how a chronic asymptomatic disease starts. Measures of prophylaxis, diagnosis, and treatment should be centered upon maintenance and restoration of a balance between the cell-oriented and organism-oriented cellular functions.

Cytokine production in patients with anorexia nervosa, bulimia nervosa, and obesity

OBJECTIVE

We previously reported elevated serum levels of the cytokines interleukin-6 (IL-6) and transforming growth factor-beta (TGF-beta) in patients with anorexia nervosa (AN). We investigated the cellular production of these two cytokines and of interferon-gamma (IFN-gamma), interleukin-1alpha (IL-1alpha), and tumor necrosis factor-alpha (TNF-alpha) in subjects with AN, bulimia nervosa (BN), and obesity as well as in normal-weight control subjects.

METHODS

Supernatant fluids from isolated peripheral blood mononuclear cells (PBMC) incubated with and without concanavalin A (ConA) were assayed for cytokine concentrations by enzyme-linked immunosorbent assay (ELISA).

RESULTS

Significant differences across the four groups were found in the stimulated cellular production of IFN-gamma and IL-6. Stimulated IFN-gamma production was elevated in the AN group compared to controls. IL-6 production was significantly elevated in obese subjects relative to the two normal-weight groups, BN and controls, and tended to be higher in the AN group than in the controls, but not significantly so. IL-1alpha production was greater in obese subjects.

CONCLUSION

The findings of increased IFN-gamma production and a tendency toward increased IL-6 production (both of which suppress food intake in animals) in individuals who severely restrict food intake suggest a potential role for these cytokines in the pathogenesis of AN. Elevated IL-6 and IL-1alpha production by PBMC in obese individuals requires further investigation to determine if these cytokines contribute to the development or perpetuation of obesity.

Pathophysiology of abomasal parasitism: is the host or parasite responsible?

Nematode larvae developing within the glands cause local loss of parietal cells and mucous cell hyperplasia whereas reduced acid secretion, increased serum gastrin and pepsinogen concentrations and generalized histological changes are associated with parasites in the abomasal lumen. Parietal cells with dilated canaliculi and/or degenerative changes typical of necrosis are present soon after the transplantation of adult worms, and abomasal secretion is also affected. Anaerobic bacteria survive in greater numbers as the pH rises, with bacterial densities becoming similar to ruminal populations at an abomasal pH of 4 and above. Failure to lyse bacteria may affect adversely the nutrition of the host. The parasites may initiate the pathophysiology through the release of excretory/secretory (ES) products which either act directly on parietal cells or indirectly through enterochromaffin-like (ECL) cells by provoking inflammation or by disrupting the protective mucosal defence system. Parietal cell dysfunction is proposed as a key event which leads to loss of mature chief cells and mucous cell hyperplasia, as well as hypergastrinaemia. Inflammation increases circulating pepsinogen concentrations and may also contribute to increased gastrin secretion. Stimulation of mucosal proliferation and differentiation of parietal cells in the isthmus by the raised serum gastrin levels will be beneficial by generating a new population of active parietal cells and adequate acid secretion.

Plasma concentrations of tumor necrosis factor-alpha (TNF-alpha) and soluble TNF receptors in patients with bulimia nervosa

BACKGROUND

Tumor necrosis factor-alpha (TNF-alpha) is a cytokine with numerous immunological and metabolic activities. In addition, TNF-alpha can stimulate a variety of physiological, neuroendocrine and behavioural responses of the central nervous system. In experimental animals, TNF-alpha induces changes in physiological and behavioural parameters which have also been observed in eating disorders. The biological activities of TNF-alpha are mediated by two structurally related, but functionally distinct receptors, TNF-RI and TNF-RII. Since injection of TNF-alpha results in increased shedding of TNF-alpha receptors, it is likely that TNF-alpha release is reflected by soluble TNF-receptors (sTNF-Rs) levels.

AIMS

We studied plasma concentrations of TNF-alpha and two sTNF-Rs (sTNF-RI and sTNF-RII) in female patients with bulimia nervosa.

DESIGN AND PATIENTS

Twenty female patients with bulimia nervosa (BN) and 20 age-matched normal women (N) were studied.

MEASUREMENTS

Plasma TNF-alpha concentrations were measured by enzyme immunoassay kit and plasma concentrations of sTNF-RI and sTNF-RII were measured by enzyme-linked immunosorbent assay.

RESULTS

Plasma TNF-alpha concentrations in BN were significantly higher than those in N (4.7+/- 0.5 ng/l vs. 1.6+/-0.1 ng/l; P<0.01). Although no significant difference was observed in plasma sTNF-RI concentrations between the two groups, plasma sTNF-RII concentrations in BN were significantly higher than those in N (2080.0+/-107.5 ng/l vs. 1569.5 +/-84.0 ng/l; P<0.01). Plasma TNF-alpha concentrations were significantly related to plasma sTNF-RI concentrations (r = 0.511, P<0.05) and to plasma sTNF-RII concentrations (r = 0.532, P<0.05) in bulimic patients. However, plasma TNF-alpha concentrations were not related to body fat mass or to bulimic behaviours in these patients.

CONCLUSIONS

Our present findings suggest that the adipose tissue may not be the immediate source of TNF-alpha in bulimic patients but the increase in plasma TNF-alpha in these patients may be derived from the central nervous system sources. The elevated sTNF-RII may reflect different shedding kinetics compared with sTNF-RI in bulimic patients.

Evidence for a positive correlation between serum cortisol levels and IL-1beta production by peripheral mononuclear cells in anorexia nervosa

A hyperactivity of the hypothalamic-pituitary-adrenal (HPA) axis has been reported in anorexia nervosa (AN), together with some immunological abnormalities, involving citokine - and particularly Tumor Necrosis-Factor-alpha (TNF-alpha) - production by polymorphonuclear cells. The ability of pro-inflammatory cytokines to activate the HPA axis is well known; however, there are no data demonstrating an interdependence between immunological and endocrine response in AN. To investigate the presence of a correlation between immune response and pituitary-adrenal function, plasma ACTH and serum cortisol concentrations were measured in 13 AN patients and in the same number of controls. TNF-alpha and interleukin (IL)-1beta production by ex-vivo unstimulated and LPS-stimulated peripheral mononuclear cells was also assessed. Circulating cortisol concentrations were higher (p<0.01) in AN (156.7 +/- 45.1 microg/l, mean +/- SD) than in controls (105.9 +/- 25.7 microg/l). Unstimulated IL-1beta release in supernatants of mononuclear cell cultures was slightly but not significantly higher in AN than in controls, while TNF-alpha release was similar in the two groups. A positive correlation was found between IL-1beta concentrations in unstimulated culture supranatants and serum cortisol levels in AN (r=0.782, p=0.002), while in normal subjects there was a trend toward a negative correlation; a slight positive correlation, while not significant, between IL-1beta and plasma ACTH, as well as between TNF-alpha and serum cortisol was also found in AN. These data suggest that the normal relationship between pro-inflammatory cytokines release, particularly IL-1beta, and cortisol secretion is deranged in AN.

Tumor necrosis factor-alpha stimulates cell proliferation in adipose tissue-derived stromal-vascular cell culture: promotion of adipose tissue expansion by paracrine growth factors

OBJECTIVE

Elevated levels of tumor necrosis factor-alpha (TNF-alpha) protein and mRNA have been reported in adipose tissue from obese humans and rodents. However, TNF-alpha has catabolic and antiadipogenic effects on adipocytes. Addressing this paradox, we tested the hypothesis that paracrine levels of TNF-alpha, alone or together with insulin-like growth factor-I (IGF-I), support preadipocyte development.

RESEARCH METHODS AND PROCEDURES

Cultured stromal-vascular cells from rat inguinal fat depots were exposed to serum-free media containing insulin and 0.2 nM TNF-alpha, 2.0 nM TNF-alpha, or 0.2 nM TNF-alpha + 1.0 nM IGF-I at different times during 7 days of culture.

RESULTS

TNF-alpha inhibited adipocyte differentiation as indicated by a reduction in both immunocytochemical reactivity for the preadipocyte-specific antigen (AD3; early differentiation marker) and glycerol-3-phosphate dehydrogenase activity (late differentiation marker). Early exposure (Days 1 through 3 of culture) to 0.2 nM TNF-alpha did not have a long term effect on inhibiting differentiation. Continuous exposure to 0.2 nM TNF-alpha from Days 1 through 7 of culture resulted in a 75% increase in cell number from control. There was a synergistic effect of 0.2 nM TNF-alpha + 1 nM IGF-I on increasing cell number by Day 7 of culture to levels greater than those observed with either treatment applied alone.

DISCUSSION

These data suggest that paracrine levels (0.2 nM) of TNF-alpha alone or in combination with IGF-I may support adipose tissue development by increasing the total number of stromal-vascular and/or uncommitted cells within the tissue. These cells may then be recruited to become preadipocytes or may alternatively serve as infrastructure to support adipose tissue growth.

Cytokines in de obsessief compulsieve stoornis en in anorexia nervosa: een overzicht

The alterations in the inflammatory response system (IRS) appear to be quite different between OCD and anorexia nervosa and are also different from the changes observed in major depression. In anorexia nervosa, there is some evidence for increased production of monocytic cytokines, i.e. tumor necrosis factor-α (TNFα) and interleukin-6 (IL-6), and decreased production of Th-1 like cytokines, i.e. IL-2 and IFNγ. In the same patients there are also signs of immunosuppression, e.g. lowered numbers of CD4 and CD8 T cells and increased production of transforming growth factor-beta (TGFβ). The increased production of monocytic cytokines may be the consequence of the hyponutritional status of those patients. The diminished production of the Th-1 like cytokines may be the consequence of at least four different factors: 1) the deficiency in nutritional factors; 2) neuroendocrine disorders, such as increased Cortisol production; 3) the increased TGFβ production; and 4) lower serum dipeptidyl peptidase activity. In OCD no consistent or specific alterations in the IRS are observed. There is no evidence that IRS activation may play a role in the pathophysiology of OCD and anorexia nervosa.

Alteration of the leptin network in late morbid obesity induced in mice by brain infection with canine distemper virus

Viruses can induce progressive neurologic disorders associated with diverse pathological manifestations, and therefore, viral infection of the brain can impair differentiated neural functions, depending on the initial viral tropism. We have previously reported that canine distemper virus (CDV) targets certain mouse brain structures, including the hypothalamus, early and selectively. Infected mice exhibit acute encephalitis, with late disease, characterized by motor impairment or obesity syndrome, appearing in some of the surviving mice several months after the initial viral replication. In the present study, we show viral persistence in the hypothalami of obese mice, as demonstrated by low, but still significant, levels of CDV nucleoprotein transcripts, associated with a dramatic decrease in F gene mRNAs. Given the pivotal role of the hypothalamus in obesity (eating behavior, energy consumption, and neuroendocrine function) and that of leptin, the adipose tissue-derived satiety factor acting through hypothalamic receptors, we analyzed the leptin networks in both obese and nonobese mice. The discrepancy found between the chronic and dramatic increase in blood leptin levels and the occurrence of obesity may be due to leptin resistance in the brain. In fact, expression of the long leptin receptor isoform, representing the functional leptin receptor, was specifically downregulated in the hypothalami of obese mice, explaining their inability to generate an adequate response to leptin in the brain. Intriguingly, during the acute phase of infection, its expression was increased in CDV-targeted structures in all infected mice and remained high in obese mice in all CDV-targeted structures, except for the hypothalamus. The biphasic change in hypothalamic leptin receptor expression seen during the progression of CDV-induced obesity provides a new paradigm for understanding mechanisms of neuroendocrinological, virus-induced abnormalities.

Anhedonic and anxiogenic effects of cytokine exposure

Systemic interleukin IL-1 beta, TNF alpha, and IL-2 profoundly influenced central monoamine activity, as well as behavioral outputs. The effects of the various cytokines were clearly distinguishable from one another, although synergistic effects were detected between several of these cytokines and between the actions of cytokines and stressors. Acutely applied IL-2 appeared to affect reward processes, but did not affect anxiety. When chronically administered, this cytokine markedly influenced working memory in a spatial learning test. In contrast to IL-2, both IL-1 beta and TNF alpha appeared to provoke an anxiogenic action, and provoked clear signs of illness. While these cytokines induced anorexia, they did not appear to affect reward processes. IL-1 beta and TNF alpha were found to act synergistically, and the TNF alpha provoked a sensitization with respect to the action of subsequent TNF alpha treatment. The findings indicated that cytokine treatments profoundly influence extrahypothalamic neurochemical functioning and may thus impact on behavioral outputs. Analyses of the behavioral and neurochemical changes elicited by cytokines, and particularly TNF alpha, need to consider not only the immediate impact of such treatments, but also the proactive effects that may be engendered.

Bulimia nervosa and autoimmunity

The autoantibodies that react with dopamine and serotonin are of interest in the study of bulimia nervosa. These neurotransmitters play an important role in appetite control, sexual and social behavior, and stress responses, all of which form a part of the clinical picture of bulimia nervosa. Are these autoantibodies involved in the serotoninergic hypofunctioning present in bulimia nervosa? Are they a part of an immunity regulation system essential for the cerebral system's homeostasis? To address these questions, 31 bulimic females (diagnosed according to DSM-III-R criteria) were compared with 10 control subjects (matched to the patients for sex, age, and demographic/psychosocial features). Measurement of the activity of natural autoantibodies reacting with dopamine, dopamine-beta-hydroxylase and serotonin was performed by an enzyme-linked immunosorbent assay (ELISA) for typical immunoglobulins (IgG, IgM, IgA). All of the autoantibodies of the IgG type were lower in the bulimic group than in the control group, a difference that was statistically significant for IgG anti-serotonin and IgG anti-dopamine. There was a trend for the amount of IgM anti-dopamine to be lower in patients than in controls. Dopamine and serotonin are specific components of brain cells. It can therefore be hypothesized that these antigens acting with autoantibodies could be the antigenic cerebral targets reacting with 'anti-brain' antibodies. The study of these specific autoantibodies provides information about the immunological characteristics that may be related to brain disturbances.