Adolescents newly diagnosed with eating disorders have structural differences in brain regions linked with eating disorder symptoms

Brain morphology in adolescent girls with first-onset anorexia nervosa

This study aimed to assess whether a young, first-onset cohort of girls with anorexia nervosa (AN) demonstrate similar findings of reduced gray and white matter volume reductions as reported in older women with chronic AN. We compared adolescents and young adults with first-onset AN to typically developing (TD) girls and investigated associations between brain volume measures and clinical symptoms. Whole-brain T1-weighted structural imaging was performed in 58 young persons with AN and 63 age, sex-, and education-matched TD participants. Participants with AN were further divided into underweight (undAN) and restored weight (restAN) groups based on body mass index length/weight standard deviation score (BMI-SDS). Eating disorder symptoms were measured by the Eating Disorder Examination (EDE) and the Eating Disorder Inventory-3 (EDI-3). Differences in brain volume measures were analyzed using separate linear regression analyses. Within the AN group, associations between brain volumes, BMI-SDS, and EDE/EDI-3 scores were analyzed. The undAN group showed significant reductions in total and cortical gray matter volumes compared to the TD group, primarily in the frontal and parietal cortices. No significant associations were found between brain volume and BMI-SDS or EDE/EDI-3 scores. Frontal and parietal cortices in adolescents and young adults with undAN are particularly affected by malnutrition, showing gray matter volume reductions even in early stages of AN. Longitudinal studies are needed to explore the effects of malnutrition on brain development and its association with clinical features of AN over time.

Cytokine and Microbiome Changes in Adolescents with Anorexia Nervosa at Admission, Discharge, and One-Year Follow-Up

Anorexia nervosa (AN) is a severe eating disorder that predominantly affects females and typically manifests during adolescence. There is increasing evidence that serum cytokine levels are altered in individuals with AN. Previous research has largely focused on adult patients, assuming a low-grade pro-inflammatory state. The serum levels of the cytokine tumour necrosis factor-alpha (TNF-α), interleukin (IL)-1β, IL-6 and IL-15, which are pro-inflammatory, were examined in 63 female adolescents with AN and 41 age-matched healthy controls (HC). We included three time points (admission, discharge, and 1-year follow-up) and investigated the clinical data to assess whether the gut microbiota was associated with cytokine alterations. Relative to the HC group, serum levels of IL-1β and IL-6 were significantly lower during the acute phase (admission) of AN. IL-1β expression was normalised to control levels after weight recovery. TNF-α levels were not significantly different between the AN and HC groups. IL-15 levels were significantly elevated in patients with AN at all time points. We found associations between cytokines and bodyweight, illness duration, depressive symptoms, and the microbiome. In contrast to most findings for adults, we observed lower levels of the pro-inflammatory cytokines IL-1β and IL-6 in adolescent patients, whereas the level of IL-15 was consistently increased. Thus, the presence of inflammatory dysregulation suggests a varied rather than uniform pro-inflammatory state.

Brain functional alterations in patients with anorexia nervosa: A meta-analysis of task-based functional MRI studies

The goal of this study was to discern the neural activation patterns associated with anorexia nervosa (AN) in response to tasks related to body-, food-, emotional-, cognitive-, and reward- processing. A meta-analysis was performed on task-based fMRI studies, revealing that patients with AN showed increased activity in the left superior temporal gyrus and bilaterally in the ACC during a reward-related task. During cognitive-related tasks, patients with AN also showed increased activity in the left superior parietal gyrus, right middle temporal gyrus, but decreased activity in the MCC. Additionally, patients with AN showed increased activity bilaterally in the cerebellum, MCC, and decreased activity bilaterally in the bilateral precuneus/PCC, right middle temporal gyrus, left ACC when they viewed food images. During emotion-related tasks, patients with AN showed increased activity in the left cerebellum, but decreased activity bilaterally in the striatum, right mPFC, and right superior parietal gyrus. Patients with AN also showed increased activity in the right striatum and decreased activity in the right inferior temporal gyrus and bilaterally in the mPFC during body-related tasks. The present meta-analysis provides a comprehensive overview of the patterns of brain activity evoked by task stimuli, thereby augmenting the current comprehension of the pathophysiology in AN.

The Association between Blood SIRT1 and Ghrelin, Leptin, and Antibody Anti-Hypothalamus: A Comparison in Normal Weight and Anorexia Nervosa

Sirtuin 1 (SIRT1) is a sensor of cell energy availability, regulating metabolic homeostasis as well as leptin and ghrelin, and it could be considered as a potential plasmatic marker. The aim of this study was to assess whether circulating SIRT1 varies consistently with leptin, ghrelin, body mass index (BMI), and IgG reactive to hypothalamic antigens in anorexia nervosa (AN). Fifty-four subjects were evaluated: 32 with AN and 22 normal-weight control subjects. Serum levels of SIRT1, leptin, ghrelin, and IgG reactive to hypothalamic antigens were evaluated by ELISA. Results showed that serum SIRT1 is increased in patients with AN, and the amount is decreased in relation to the duration of the illness. SIRT1 concentration approaches the values obtained for the control group, although the difference is still statistically significant. A negative correlation between serum SIRT1 values and leptin or BMI values has been found. On the contrary, a positive correlation between SIRT1 and ghrelin or IgG specific for hypothalamic antigens is reported. These findings suggest that a peripheral evaluation of SIRT1 could be a possible clinical/biochemical parameter related to AN. In addition, we can assume that SIRT1 is related to autoantibody production and may correlate with the intensity/severity of AN. Thus, reducing the production of autoantibodies specific for hypothalamic cells could be a sign of improvement of the clinical condition.

Exploration of the relationships between clinical traits and functional connectivity based on surface morphology abnormalities in bulimia nervosa

BACKGROUND

Bulimia nervosa is a recurrent eating disorder with uncertain pathogenesis. Recently, there has been growing interest in using neuroimaging techniques to explore brain structural and functional alterations in bulimia nervosa, but the findings of previous studies have a great number of inconsistencies.

METHODS

Here, we collected anatomical and resting-state functional magnetic resonance imaging data from 43 bulimia nervosa patients and 34 matched healthy controls (HCs). We applied a surface-based morphology analysis to explore brain cortical morphology differences and a novel surface-based functional connectivity (FC) analysis to investigate functional abnormalities. Principal component analysis was performed to analyze the behavioral data of the participants. We further analyzed the relationships between abnormalities in cortical characteristics or FC and clinical features.

RESULTS

We observed increased greater sulcal depth in the right superior temporal gyrus (STG) and the right medial orbitofrontal cortex (mOFC) in bulimia nervosa patients than in the HCs. Additionally, the patients exhibited increased FC between the right STG and right ventral tegmental area but decreased function between the right mOFC and right putamen, which was significantly negatively correlated with the first principal component reflecting the severity of bulimia nervosa symptom.

CONCLUSIONS

Our findings provide evidence of neuroanatomical and functional abnormalities in bulimia nervosa patients. Moreover, the FC between the right mOFC and right putamen was associated with symptom severity of bulimia nervosa, which may be a neural marker and involved in the neuropathological mechanism of bulimia nervosa.

The cerebellum gains weight: A systematic review of alterations in cerebellar volume and cerebro-cerebellar functional alterations in individuals with eating disorders

BACKGROUND

Brain imaging studies on eating disorders (EDs) often reported volumetric and functional changes involving the cerebellum. Nevertheless, few studies performed in-depth examinations and suggested a cerebellar role in the EDs' pathophysiology.

METHODS

A systematic literature search on volumetric changes and functional alterations involving the cerebellum in individuals with EDs was conducted using PubMed, PsychInfo and Web of Science. This review was conducted according to the Preferred Reporting Items for Systematic Reviews (PRISMA) statement and Rayyan web application for screening studies.

RESULTS

Twenty-four papers reporting cerebellar alterations in individuals with EDs were included in the study: 9 assessing brain volumetric changes, 9 investigating task-based functional brain activation and 6 investigating brain functional connectivity at rest. Most studies focused on anorectic-type EDs (n.22), while fewer involved bulimic-type EDs (n.9) and eating disorders not otherwise specified (n.2), revealing subtypes-specific patterns of altered cerebellar volume and functionality.

CONCLUSIONS

This review proposes critical arguments to consider the cerebellum as a key structure in the pathophysiology of EDs that requires further forthcoming exploration.

Phonological working memory is adversely affected in adults with anorexia nervosa: a systematic literature review

PURPOSE

Cognitive restraint has potentiating and deleterious effects on working memory (WM) in anorexia nervosa (AN). Conflicting evidence may be due to heterogeneity of tasks examining different WM components (e.g., verbal/auditory versus visuospatial), and differences in adolescent versus adult AN. Additionally, differential cognitive profiles of restricting versus binge/purging subtypes, comorbid psychiatric disorders and psychotropic medication use may confound findings.

METHODS

To address these conflicts, 25 studies, published between 2016 and 2021, investigating WM in children, adolescents and adults with AN were systematically reviewed using PRISMA guidelines.

RESULTS

In 71% of WM tasks, no difference in performance between AN patients and age-matched controls was reported, while 29% of WM tasks showed worse performance. Adults with AN displayed deficits in 44% of the verbal/auditory tasks, while performance remained unaffected in 86% of visuospatial tasks.

CONCLUSION

Examining age groups and WM subsystems separately revealed novel findings of differentially affected WM components in AN. Comorbidities and psychotropic medications were common among AN participants and should be regarded as critical confounding factors for WM measures. Future studies examining different components of WM, acknowledging these confounding factors, may reveal specific deficits in AN to aid treatment improvement strategies.

LEVEL OF EVIDENCE

I, systematic review.

Neural Correlates of Executive Functioning in Anorexia Nervosa and Obsessive-Compulsive Disorder

Anorexia nervosa (AN) and obsessive-compulsive disorder (OCD) are commonly reported to co-occur and present with overlapping symptomatology. Executive functioning difficulties have been implicated in both mental health conditions. However, studies directly comparing these functions in AN and OCD are extremely limited. This review provides a synthesis of behavioral and neuroimaging research examining executive functioning in AN and OCD to bridge this gap in knowledge. We outline the similarities and differences in behavioral and neuroimaging findings between AN and OCD, focusing on set shifting, working memory, response inhibition, and response monitoring. This review aims to facilitate understanding of transdiagnostic correlates of executive functioning and highlights important considerations for future research. We also discuss the importance of examining both behavioral and neural markers when studying transdiagnostic correlates of executive functions.

Altered gray matter volume and functional connectivity in medial orbitofrontal cortex of bulimia nervosa patients: A combined VBM and FC study

Brain structural and functional abnormalities have been shown to be involved in the neurobiological underpinnings of bulimia nervosa (BN), while the mechanisms underlying this dysregulation are unclear. The main goal of this investigation was to explore the presence of brain structural alterations and relevant functional changes in BN. We hypothesized that BN patients had regional gray matter volume abnormalities and corresponding resting-state functional connectivity (rsFC) changes compared with healthy controls. Thirty-one BN patients and twenty-eight matched healthy controls underwent both high-resolution T1-weighted magnetic resonance imaging (MRI) and resting-state functional MRI. Structural analysis was performed by voxel-based morphometry (VBM), with subsequent rsFC analysis applied by a seed-based, whole-brain voxelwise approach using the abnormal gray matter volume (GMV) region of interest as the seed. Compared with the controls, the BN patients showed increased GMV in the left medial orbitofrontal cortex (mOFC). The BN patients also exhibited significantly increased rsFC between the left mOFC and the right superior occipital gyrus (SOG) and decreased rsFC between the left mOFC and the left precentral gyrus, postcentral gyrus, and supplementary motor area (SMA). Furthermore, the z values of rsFC between the left mOFC and right SOG was positively correlated with the Dutch Eating Behavior Questionnaire-external eating scores. Findings from this investigation further suggest that the mOFC plays a crucial role in the neural pathophysiological underpinnings of BN, which may lead to sensorimotor and visual regions reorganization and be related to representations of body image and the drive behind eating behavior. These findings have important implications for understanding neural mechanisms in BN and developing strategies for prevention.

Lower serum levels of IL-1β and IL-6 cytokines in adolescents with anorexia nervosa and their association with gut microbiota in a longitudinal study

INTRODUCTION

Anorexia nervosa (AN) is an often chronic and debilitating psychiatric disease whose etiology is not completely understood. Recently, a potential role of inflammation has emerged in other psychiatric diseases, such as depression, PTSD and schizophrenia. The first results in adults with AN seemed to confirm a low-grade proinflammatory state until recent studies presented more differential findings. Studying adolescents with a shorter illness duration and fewer confounding factors might help elucidate the role of inflammation in the underlying pathophysiology of AN; however, the few available studies in adolescents remain ambiguous, and no longitudinal data are available in this age range.

METHODS

We examined the proinflammatory cytokines Tumor Necrosis Factor-alpha (TNF-α), Interleukin (IL)-1β, IL-6, IL-15, and the cytokine-receptor IL-6 Receptor alpha (IL-6 Rα) in the serum of twenty-two hospitalized female adolescent patients with AN longitudinally at admission and discharge and compared their results to nineteen healthy controls (HC). We also collected clinical data and stool samples that were analyzed with 16S rRNA amplicon sequencing to explore potential influencing factors of cytokine changes.

RESULTS

TNF-α serum levels were significantly elevated in patients with AN at admission, while IL-1β and IL-6 levels were lower at admission and discharge than in HC. After treatment, we also found significantly elevated levels of IL-6 Rα compared to HC, while IL-15 did not show significant changes. Exploratory analyses revealed positive associations of cytokine and genus-level changes between admission and discharge for IL-1β (Bacteroides) and IL-15 (Romboutsia), and negative associations for IL-15 (Anaerostipes) and TNF-α (uncultured Lachnospiraceae).

CONCLUSION

We confirmed a previous finding of elevated levels of TNF-α also in adolescents with AN; however, the reduced IL-1β and IL-6 levels differed from the mostly increased levels found in adults. A mixed pro- and anti-inflammatory state appears to be present in adolescents, potentially due to their shorter illness duration. The gut microbiota, with its regulatory function on cytokine production, might play a role in mediating these inflammatory processes in AN and could offer targets for new therapeutic approaches.

Multimodal neuroimaging in anorexia nervosa

Anorexia nervosa (AN) is a severe and complex psychiatric disorder characterized by intense fear about weight gain and finalized to food-related control behaviors. Growing interest has been demonstrated about neurobiological processes subtend to AN physiopathology. The present review aimed to collect neurostructural and neurofunctional available data from 2010 to 2019. Results have been organized according to the neuroimaging technique employed, also including a specific section on electroencephalographic results, mostly neglected in previous reviews. Diffuse cerebral vulnerability has been demonstrated and the contribution of several structures has been identified. Insula, cingulate cortex, parietal and frontal areas are primarily involved both by structural and functional perspectives. Moreover, consistent alterations in white matter integrity and brain electrical activity have been reported. Neuroimaging findings give a substantial contribution to AN pathophysiological description, also in order to understand altered but reversible processes in the passage from acute illness phase to disorder's remission, useful also for defining therapy.

Lower gray matter volumes of frontal lobes and insula in adolescents with anorexia nervosa restricting type: Findings from a Brain Morphometry Study

BACKGROUND

Brain atrophy in anorexia nervosa (AN) is one of the most marked structural brain changes observed in mental disorders. In this study, we propose a whole brain analysis approach to characterize global and regional cerebral volumes in adolescents with restricting-type anorexia nervosa (AN-r).

METHODS

A total of 48 adolescent females (age range 13-18 years) were enrolled in the study (24 right-handed AN-r in the early stages of the illness and treated in the same clinical setting and 24 age-matched healthy controls [HC]). High-resolution T1-weighted magnetic resonance images were acquired. Cerebral volumes, including the total amounts of gray matter (GM), white matter (WM), and cerebrospinal fluid (CSF) were obtained with the Statistical Parametric Mapping software (SPM8); specific cortical regional volumes were computed by applying an atlas-based cortical parcellation to the SPM8 GM segments. Analysis of variance (ANOVA) was performed to identify any significant between-group differences in global and regional brain volumes.

RESULTS

The analyses revealed reduced total GM volumes (p = 0.02) and increased CSF (p = 0.05) in AN-r, compared with HC. No significant between-group difference was found in WM volumes. At the regional level, significantly lower GM volumes in both frontal lobes (p = 0.006) and in the left insula (p = 0.016) were detected. No significant relationships were found between cerebral volumes and duration of illness, psychiatric comorbidities, psychopharmacological treatment, prepubertal phase, or presence of amenorrhea.

CONCLUSIONS

The topographic distribution of GM reduction in a homogenous group of AN-r involves regions responsible for the emotional and cognitive deficits associated with the illness. These findings are discussed in relation to the roles of the insular cortex and the frontal lobes.

The Neurobiology of Eating Disorders

Eating disorders are severe psychiatric illnesses with a typical age of onset in adolescence. Brain research in youth and young adults may help us identify specific neurobiology that contributes to onset and maintenance of those disorders. This article provides a state-of-the-art review of our current understanding of the neurobiology of anorexia nervosa and bulimia nervosa. This includes brain structure and function studies to understand food restriction, binge-eating or purging behaviors, cognitive and emotional factors, as well as interoception. Binge-eating disorder and avoidant restrictive food intake disorder are also discussed, but the literature is still very small.

The Role of Working Memory for Cognitive Control in Anorexia Nervosa versus Substance Use Disorder

Prefrontal cortex executive functions, such as working memory (WM) interact with limbic processes to foster impulse control. Such an interaction is referred to in a growing body of publications by terms such as cognitive control, cognitive inhibition, affect regulation, self-regulation, top-down control, and cognitive–emotion interaction. The rising trend of research into cognitive control of impulsivity, using various related terms reflects the importance of research into impulse control, as failure to employ cognitions optimally may eventually result in mental disorder. Against this background, we take a novel approach using an impulse control spectrum model – where anorexia nervosa (AN) and substance use disorder (SUD) are at opposite extremes – to examine the role of WM for cognitive control. With this aim, we first summarize WM processes in the healthy brain in order to frame a systematic review of the neuropsychological, neural and genetic findings of AN and SUD. In our systematic review of WM/cognitive control, we found n = 15 studies of AN with a total of n = 582 AN and n = 365 HC participants; and n = 93 studies of SUD with n = 9106 SUD and n = 3028 HC participants. In particular, we consider how WM load/capacity may support the neural process of excessive epistemic foraging (cognitive sampling of the environment to test predictions about the world) in AN that reduces distraction from salient stimuli. We also consider the link between WM and cognitive control in people with SUD who are prone to ‘jumping to conclusions’ and reduced epistemic foraging. Finally, in light of our review, we consider WM training as a novel research tool and an adjunct to enhance treatment that improves cognitive control of impulsivity.

Evaluating anorexia-related brain atrophy using MP2RAGE-based morphometry

AIM

To evaluate brain atrophy in anorexic patients by automated cerebral segmentation with the magnetization-prepared 2 rapid acquisition gradient echo (MP2RAGE) MRI sequence.

MATERIAL AND METHODS

Twenty patients (female; mean age, 27.9 years), presenting consecutively for brain MRI between August 2014-December 2016 with clinical suspicion of anorexia nervosa and BMI<18.5 kg/m² were included. Controls were ten healthy females (mean age, 26.5 years). Automated brain morphometry was performed based on MP2RAGE. Means of morphometric results in the two groups were compared and correlation with BMI was analysed.

RESULTS

Significantly lower volumes of total brain, grey matter (GM), white matter (WM), cerebellum and insula were found in anorexic patients. Anorexics had higher volumes of CSF, ventricles, lateral ventricles and third ventricle. When adjusted means for weight and height were compared, the volume of WM and cerebellum were not significantly different. However, volume of WM was significantly affected by weight and positively correlated with BMI. Significant positive correlations were found between BMI and volumes of total brain, GM, cortical GM and WM. BMI was negatively correlated with volumes of CSF and third ventricle.

CONCLUSION

Brain atrophy was demonstrated in anorexic patients with MP2RAGE-based automated segmentation, which seems to reliably estimate brain volume.

KEY POINTS

• Automated brain segmentation based on 3-D MRI seems to reliably estimate brain volume. • This technique detected brain atrophy in patients suffering from anorexia nervosa. • Brain changes in anorexia nervosa can be quantitatively and qualitatively followed-up by MRI.