Metabolic changes in the brain of patients with anorexia and bulimia nervosa as detected by proton magnetic resonance spectroscopy

Triangulating brain alterations in anorexia nervosa: a multimodal investigation of magnetic resonance spectroscopy, morphometry and blood-based biomarkers

The acute state of anorexia nervosa (AN) is associated with widespread reductions in cortical gray matter (GM) thickness and white matter (WM) volume, suspected changes in myelin content and elevated levels of the neuronal damage marker neurofilament light (NF-L), but the underlying mechanisms remain largely unclear. To gain a deeper understanding of brain changes in AN, we applied a multimodal approach combining advanced neuroimaging methods with analysis of blood-derived biomarkers. In addition to standard measures of cortical GM thickness and WM volume, we analyzed tissue-specific profiles of brain metabolites using multivoxel proton magnetic resonance spectroscopy, T1 relaxation time as a proxy of myelin content leveraging advanced quantitative MRI methods and serum NF-L concentrations in a sample of 30 female, predominately adolescent patients with AN and 30 age-matched female healthy control participants. In patients with AN, we found a reduction in GM cortical thickness and GM total N-acetyl aspartate. The latter predicted higher NF-L levels, which were elevated in AN. Furthermore, GM total choline was elevated. In WM, there were no group differences in either imaging markers, choline levels or N-acetyl aspartate levels. The current study provides evidence for neuronal damage processes as well as for increased membrane lipid catabolism and turnover in GM in acute AN but no evidence for WM pathology. Our results illustrate the potential of multimodal research including tissue-specific proton magnetic resonance spectroscopy analyses to shed light on brain changes in psychiatric and neurological conditions, which may ultimately lead to better treatments.

Ketamine and Zinc: Treatment of Anorexia Nervosa Via Dual NMDA Receptor Modulation

Anorexia nervosa is a disorder associated with serious adverse health outcomes, for which there is currently considerable treatment ineffectiveness. Characterised by restrictive eating behaviours, distorted body image perceptions and excessive physical activity, there is growing recognition anorexia nervosa is associated with underlying dysfunction in excitatory and inhibitory neurometabolite metabolism and signalling. This narrative review critically explores the role of N-methyl-D-aspartate receptor-mediated excitatory and inhibitory neurometabolite dysfunction in anorexia nervosa and its associated biomarkers. The existing magnetic resonance spectroscopy literature in anorexia nervosa is reviewed and we outline the brain region-specific neurometabolite changes that have been reported and their connection to anorexia nervosa psychopathology. Considering the proposed role of dysfunctional neurotransmission in anorexia nervosa, the potential utility of zinc supplementation and sub-anaesthetic doses of ketamine in normalising this is discussed with reference to previous research in anorexia nervosa and other neuropsychiatric conditions. The rationale for future research to investigate the combined use of low-dose ketamine and zinc supplementation to potentially extend the therapeutic benefits in anorexia nervosa is subsequently explored and promising biological markers for assessing and potentially predicting treatment response are outlined.

Characterizing cerebral metabolite profiles in anorexia and bulimia nervosa and their associations with habitual behavior

Anorexia nervosa (AN) and bulimia nervosa (BN) are associated with altered brain structure and function, as well as increased habitual behavior. This neurobehavioral profile may implicate neurochemical changes in the pathogenesis of these illnesses. Altered glutamate, myo-inositol and N-acetyl aspartate (NAA) concentrations are reported in restrictive AN, yet whether these extend to binge-eating disorders, or relate to habitual traits in affected individuals, remains unknown. We therefore used single-voxel proton magnetic resonance spectroscopy to measure glutamate, myo-inositol, and NAA in the right inferior lateral prefrontal cortex and the right occipital cortex of 85 women [n = 22 AN (binge-eating/purging subtype; AN-BP), n = 33 BN, n = 30 controls]. To index habitual behavior, participants performed an instrumental learning task and completed the Creature of Habit Scale. Women with AN-BP, but not BN, had reduced myo-inositol and NAA concentrations relative to controls in both regions. Although patient groups had intact instrumental learning task performance, both groups reported increased routine behaviors compared to controls, and automaticity was related to reduced prefrontal glutamate and NAA participants with AN-BP. Our findings extend previous reports of reduced myo-inositol and NAA levels in restrictive AN to AN-BP, which may reflect disrupted axonal-glial signaling. Although we found inconsistent support for increased habitual behavior in AN-BP and BN, we identified preliminary associations between prefrontal metabolites and automaticity in AN-BP. These results provide further evidence of unique neurobiological profiles across binge-eating disorders.

Metabolic changes in the cingulate gyrus, precuneus, and white matter in anorexia nervosa using multivoxel MR spectroscopy

Background and Purpose

This study aimed to highlight anorexia nervosa‐related metabolic changes in different brain regions with different gray and white matter contents.

Methods

In a prospective study, 25 anorexic patients with mean body mass index (BMI) of 14.79 kg/m² (range 10.04–20.58) were compared with 15 healthy controls with mean BMI of 21.08 kg/m² (range 18.36–27.34). Two‐dimensional magnetic resonance spectroscopic imaging was acquired in the axial plane above the corpus callosum, including frontal, precentral, postcentral, cingular, and parietal regions, as well as the precuneus, each voxel containing gray and white matter.

Results

In the anorexic group, a significant increase of choline/creatine was observed in all brain regions except the precuneus: frontal (p = 0.009), cingulate (p = 0.001), precentral (p = 0.001), postcentral (p = 0.001), and parietal (p = 0.002); and in white and gray matter (p< 0.001). Macromolecules09/creatine was decreased in the following regions: frontal (p = 0.003), cingulate (p< 0.001), precentral (p = 0.004), and precuneus (p = 0.007), and in white and gray matter (p< 0.05). We observed significantly lower values of N‐acetyl aspartate/creatine in the frontal (p < 0.001) and precentral (p< 0.001) regions and in voxels containing more than 50% white matter (p = 0.001); and significantly lower values of myo‐inositol/creatine in the precentral (p = 0.006), postcentral (p< 0.001), and precuneus (p = 0.006) regions.

Conclusions

We observed an increase in choline/creatine in anorexics, possibly reflecting increased cell turnover; a decrease in macromolecules, which was particularly low in the cingulate and precuneus the former being known to be altered in eating disorders; and a decrease in N‐acetyl aspartate/creatine considered as a marker of neuronal density and function.

Neuroimaging Findings in Adolescents and Young Adults with Anorexia Nervosa: A Systematic Review

BACKGROUND

Anorexia nervosa (AN) is a serious, multifactorial mental disorder affecting predominantly young females. This systematic review examines neuroimaging findings in adolescents and young adults up to 24 years old, in order to explore alterations associated with disease pathophysiology.

METHODS

Eligible studies on structural and functional brain neuroimaging were sought systematically in PubMed, CENTRAL and EMBASE databases up to 5 October 2020.

RESULTS

Thirty-three studies were included, investigating a total of 587 patients with a current diagnosis of AN and 663 healthy controls (HC). Global and regional grey matter (GM) volume reduction as well as white matter (WM) microstructure alterations were detected. The mainly affected regions were the prefrontal, parietal and temporal cortex, hippocampus, amygdala, insula, thalamus and cerebellum as well as various WM tracts such as corona radiata and superior longitudinal fasciculus (SLF). Regarding functional imaging, alterations were pointed out in large-scale brain networks, such as default mode network (DMN), executive control network (ECN) and salience network (SN). Most findings appear to reverse after weight restoration. Specific limitations of neuroimaging studies in still developing individuals are also discussed.

CONCLUSIONS

Structural and functional alterations are present in the early course of the disease, most of them being partially or totally reversible. Nonetheless, neuroimaging findings have been open to many biological interpretations. Thus, more studies are needed to clarify their clinical significance.

Insular Cell Integrity Markers Linked to Weight Concern in Anorexia Nervosa-An MR-Spectroscopy Study

Objective: An insular involvement in the pathogenesis of anorexia nervosa (AN) has been suggested in many structural and functional neuroimaging studies. This magnetic resonance spectroscopy (MRS) study is the first to investigate metabolic signals in the anterior insular cortex in patients with AN and recovered individuals (REC). Method: The MR spectra of 32 adult women with AN, 21 REC subjects and 33 healthy controls (HC) were quantified for absolute N-acetylaspartate (NAA), glutamate + glutamine (Glx), total choline, myo-inositol, creatine concentrations (mM/L). After adjusting the metabolite concentrations for age and partial gray/white matter volume, group differences were tested using one-way multivariate analyses of variance (MANOVA). Post-hoc analyses of variance were applied to identify those metabolites that showed significant group effects. Correlations were tested for associations with psychometric measures (eating disorder examination), duration of illness, and body mass index. Results: The MANOVA exhibited a significant group effect. The NAA signal was reduced in the AN group compared to the HC group. The REC and the HC groups did not differ in metabolite concentrations. In the AN group, lower NAA and Glx signals were related to increased weight concern. Discussion: We interpret the decreased NAA availability in the anterior insula as a signal of impaired neuronal integrity or density. The association of weight concern, which is a core feature of AN, with decreased NAA and Glx indicates that disturbances of glutamatergic neurotransmission might be related to core psychopathology in AN. The absence of significant metabolic differences between the REC and HC subjects suggests that metabolic alterations in AN represent a state rather than a trait phenomenon.

Brain glutamate in anorexia nervosa: a magnetic resonance spectroscopy case control study at 7 Tesla

RATIONALE

Anorexia nervosa (AN) is a serious psychiatric disorder with high morbidity and mortality. There are no established pharmacological treatments and the neurobiology of the condition is poorly understood. Previous studies using magnetic resonance spectroscopy (MRS) have shown that AN may be associated with reductions in indices of brain glutamate; however, at conventional field strengths (≤3 T), it is difficult to separate glutamate from its precursor and metabolite, glutamine.

OBJECTIVES

The objective of the present study was to use high field (7 T) MRS to measure concentrations of glutamate, in three separate brain voxels, in women with AN.

METHODS

We studied 13 female participants with AN and 12 healthy female controls who underwent MRS scanning at 7 T with voxels placed in anterior cingulate cortex, occipital cortex and putamen. Neurometabolites were calculated using the unsuppressed water signal as a reference and corrected for individual cerebrospinal fluid concentration in the voxel.

RESULTS

We found that participants with AN had significantly lower concentrations of glutamate in all three voxels (mean reduction 8%, p = 0.002) but glutamine levels were not altered. Concentrations of N-acetylaspartate, creatine, GABA and glutathione were also unchanged. However, inositol was lower in AN participants in anterior cingulate (p = 0.022) and occipital cortex (p = 0.002).

CONCLUSIONS

Women with AN apparently have widespread reductions in brain glutamate. Further work will be needed to assess if this change has pathophysiological relevance or whether it is a consequence of the many physical changes produced in AN by food restriction.

Morphological Changes in the Brain of Acutely Ill and Weight-Recovered Patients with Anorexia Nervosa

Objective: Acute anorexia nervosa (AN) leads to reduced gray (GM) and white matter (WM) volume in the brain, which however improves again upon restoration of weight. Yet little is known about the extent and clinical correlates of these brain changes, nor do we know much about the time-course and completeness of their recovery. Methods: We conducted a meta-analysis and a qualitative review of all magnetic resonance imaging studies involving volume analyses of the brain in both acute and recovered AN. Results: We identified structural neuroimaging studies with a total of 214 acute AN patients and 177 weight-recovered AN patients. In acute AN, GM was reduced by 5.6% and WM by 3.8% compared to healthy controls (HC). Short-term weight recovery 2–5 months after admission resulted in restitution of about half of the GM aberrations and almost full WM recovery. After 2–8 years of remission GM and WM were nearly normalized, and differences to HC (GM: –1.0%, WM: –0.7%) were no longer significant, although small residual changes could not be ruled out. In the qualitative review some studies found GM volume loss to be associated with cognitive deficits and clinical prognosis. Conclusions: GM and WM were strongly reduced in acute AN. The completeness of brain volume rehabilitation remained equivocal.

Review

Neuroanatomical and functional studies in the eating disorders (ED) are reviewed. Typically, anorexia nervosa (AN) is associated with cerebral spinal fluid spaces enlargement which generally recover as a function of re-feeding. However, specific cortical areas fail to correct in weight restored anorectic patients suggesting trait-related abnormalities. Functional changes in AN associated with starvation reverse with weight recovery, however, reduced 5-HT2A receptor binding may be fundamental to the pathophysiology of AN since this remains after long term weight restoration. Structural studies of bulimia nervosa (BN) provide evidence of brain atrophy, in the absence of significant weight loss but potentially related to chronic dietary restriction. Functional investigations reveal reduced thalamic and hypothalamic serotonin transporter availability in BN which increases with longer illness duration. Thus, BN is associated with substantial structural and functional alterations despite normal weight. Recent advances in neuroimaging techniques and their interpretation are increasing our understanding of normal processes in the control of food intake including neuroanatomical correlates of hunger and satiety. Taken together with the structural and functional changes observed in the ED, neuroimaging provides a powerful platform to identify the underlying trait-related pathophysiological mechanisms in the aetiology and maintenance of AN and BN.

Metabolic gray matter changes of adolescents with anorexia nervosa in combined MR proton and phosphorus spectroscopy

INTRODUCTION

There are hints for changes in phospholipid membrane metabolism and structure in the brain of adolescents with anorexia nervosa (AN) using either proton ((1)H) or phosphorus ((31)P) magnetic resonance spectroscopic imaging (MRSI). We aimed to specify these pathological metabolite changes by combining both methods with additional focus on the neuronal metabolites glutamate (Glu) and N-acetyl-l-aspartate (NAA).

METHODS

Twenty-one female patients (mean 14.4  ±  1.9 years) and 29 female controls (mean 16  ±  1.6 years) underwent (1)H and (31)P MRSI at 3 T applied to the centrum semiovale including the anterior cingulate cortex. We assessed gray matter (GM) and white matter (WM) metabolite concentration changes of the frontal and parietal brain measuring choline(Cho)- and ethanolamine(Eth)-containing compounds, Glutamate (Glu) and glutamine (Gln) and their sum (Glx), myoinositol, NAA, and high-energy phosphates.

RESULTS

For (1)H MRSI, a clear discrimination between GM and WM concentrations was possible, showing an increase of Glx (p < 0.001), NAA (frontal p < 0.05), pooled creatine (tCr) (p < 0.001), and choline (tCho) (p < 0.05) in the GM of AN patients. The lipid catabolites glycerophosphocholine (p < 0.07) and glycerophosphoethanolamine (p < 0.03) were increased in the parietal region.

CONCLUSIONS

Significant changes in GM metabolite concentrations were observed in AN possibly triggered by elevated excitotoxin Glu. Increased tCho may indicate modifications of membrane phospholipids due to increased catabolism in the parietal region. Since no significant changes in phosphorylated choline compounds were found for the frontal region, the tCho increase in this region may hint to fluidity changes.

Magnetic resonance spectroscopy of the anterior cingulate cortex in eating disorders

The anterior cingulate cortex plays a key role in eating disorders (ED), but it remains an open question whether there are deviations of the neurochemistry of this region in patients with ED. Seventeen adult female patients with ED (10 with bulimia nervosa, 7 with anorexia nervosa) were compared to 14 matched female healthy controls using single voxel magnetic resonance spectroscopy of the anterior cingulate cortex. Group comparisons did not reveal any differences between patients and controls, but a positive correlation between glutamate and myo-inositol signals with "drive for thinness" in patients with bulimia nervosa was found in exploratory correlation analyses.

Prefrontal brain metabolites in short-term weight-recovered adolescent anorexia nervosa patients

Various neuroimaging techniques have revealed morphological and functional alterations in anorexia nervosa (AN), although few spectroscopic magnetic resonance studies have examined short-term weight-recovered AN patients. Subjects were 32 female adolescent patients (between 13 and 18 years old) seen consecutively in our department and who met DSM-IV diagnostic criteria for AN. All of them had received a minimum of six months of treatment and were short-term weight-recovered (for one to three months) with a body mass index ranging from 18 to 23. A group of 20 healthy female volunteer controls of similar age were also included. All subjects were assessed with psychopathological scales and magnetic resonance spectroscopy. Total choline (Cho) (p=0.007) and creatine (Cr) (p=0.008) levels were significantly higher in AN patients than in controls. AN patients receiving psychopharmacological treatment with SSRIs (N=9) had metabolite levels similar to control subjects, but patients without this treatment did not. The present study shows abnormalities in brain neurometabolites related to Cho compounds and Cr in the prefrontal cortex in short-term weight-recovered adolescent AN patients, principally in patients not undergoing psychopharmacological treatment. More studies with larger samples are necessary to test the generalizability of the present results.

Serum glutamine, set-shifting ability and anorexia nervosa

BACKGROUND

Set-shifting is impaired in people with anorexia nervosa (AN), but the underlying physiological and biochemical processes are unclear. Animal studies have established that glutamatergic pathways in the prefrontal cortex play an important role in set-shifting ability. However, it is not yet understood whether levels of serum glutamatergic amino acids are associated with set-shifting performance in humans. The aim of this study was to determine whether serum concentrations of amino acids related to glutamatergic neurotransmission (glutamine, glutamate, glycine, l-serine, d-serine) are associated with set-shifting ability in people with acute AN and those after recovery.

METHODS

Serum concentrations of glutamatergic amino acids were measured in 27 women with current AN (AN group), 18 women recovered from AN (ANRec group) and 28 age-matched healthy controls (HC group). Set-shifting was measured using the Wisconsin Card Sorting Test (WCST) and the Trail Making Task (TMT). Dimensional measures of psychopathology were used, including the Eating Disorder Examination Questionnaire (EDEQ), the Maudsley Obsessive-Compulsive Inventory (MOCI) and the Hospital Anxiety and Depression Scale (HADS).

RESULTS

Serum glutamine concentrations in the AN group (1,310.2 +/- 265.6 muM, mean +/- SD) were significantly higher (by approximately 20%) than those in the HC group (1,102.9 +/- 152.7 muM, mean +/- SD) (F(2, 70) = 6.3, P = 0.003, 95% CI 61.2 to 353.4). Concentrations of serum glutamine were positively associated with markers of the illness severity: a negative correlation was present between serum glutamine concentrations and body mass index (BMI) and lowest BMI and a positive correlation was found between duration of illness and EDEQ. The AN group showed significantly impaired set shifting in the WCST, both total errors, and perseverative errors. In the AN group, there were no correlations between serum glutamine concentrations and set shifting.

CONCLUSIONS

Serum concentrations of glutamine may be a biomarker of illness severity in people with AN. It does not appear to be directly associated with changes in executive function.

[Anorexia nervosa and nervus peronaeus lesions]

Anorexia nervosa could be associated with numerous medical complications. In addition, malnutrition can cause different problems of central nervous system, whereas reports on periphere nerve lesions are rare. We report a case of a 14 8/12 years old girl suffering from anorexia nervosa since five months, who presented with peroneal nerve palsy. In association to anorexia nervosa the prognosis of this mononeuropathy seems to be good. Anorectic patients with neurological complications need an interdisciplinary medical treatment.

Neuroimaging in eating disorders and obesity: implications for research

Medicine and psychiatry have benefited from developments in investigational techniques. Neuroimaging is one such domain that has technically progressed enormously in recent years, resulting in, for example, higher temporal and spatial resolution. Neuroimaging techniques have been widely used in a range of psychiatric disorders, providing new insights into neural brain circuits and neuroreceptor functions in vivo. These imaging techniques allow researchers to study not only the configuration of brain structures but also aspects of normal and anomalous human behavior more accurately.

Adolescent anorexia nervosa: cross-sectional and follow-up frontal gray matter disturbances detected with proton magnetic resonance spectroscopy

There are very few magnetic resonance spectroscopy studies in anorexia nervosa and none of them with young adolescent patients. We studied 12 anorexia nervosa (DSM-IV) patients aged 11-17 consecutively admitted to an Eating Disorders Unit. An evaluation with laboratory data, psychopathological scales, magnetic resonance spectroscopy ((1)H MRS) and a neuropsychological battery was carried out at admission and after 7 months' follow-up and weight recovery. Psychopathological and neuropsychological and MRS examinations were also performed in 12 control subjects. In the MRS study at the frontal gray matter, the anorexic group had a significantly lower N-acetyl-aspartate (NAA) (p = .002), glutamate/glutamine (Glx) (p = .010) and myo-Inositol (mI) (p = .022) than the control group. The NAA correlated positive and significantly with triiodothyronin (Rho = .64) and the estimate level of intelligence measured with the vocabulary subtest of the WISC-R (Rho=.64). There were also positive correlations with body mass index (Rho = .47) and with attention measured with the coding subtest of the WISC-R (Rho=.51) and negative with loss of weight (Rho = -.51) but they were not statistically significant. At follow-up, there was an increase in body mass index (p=.002), triiodothyronin (p = .005), and insulin-like growth factor 1 (p = .017) and a decrease in cortisol (p = .005). In the MRS a significant increase (p = .013) in NAA was observed. The conclusion would be that NAA, Glx and mI are low in the frontal gray matter of adolescents with anorexia nervosa and specially NAA correlates with some nutritional and cognitive parameters. These alterations seem to be reversible in young patients.

A review of the possible relevance of inositol and the phosphatidylinositol second messenger system (PI-cycle) to psychiatric disorders--focus on magnetic resonance spectroscopy (MRS) studies

Myo-inositol is an important part of the phosphatidylinositol second messenger system (PI-cycle). Abnormalities in nerve cell myo-inositol levels and/or PI-cycle regulation has been suggested as being involved in the pathophysiology and/or treatment of many psychiatric disorders including bipolar disorder, major depressive disorder, panic disorder, obsessive-compulsive disorder, eating disorders and schizophrenia. This review examines the metabolism and biochemical importance of myo-inositol and the PI-cycle. It relates this to the current in vivo evidence for myo-inositol and PI-cycle involvement in these psychiatric disorders, particularly focusing upon the magnetic resonance spectroscopy (MRS) findings in patient studies to date. From this review it is concluded that while the evidence suggests probable relevance to the pathophysiology and/or treatment of bipolar disorder, there is much less support for a significant role for the PI-cycle or myo-inositol in any other psychiatric disorder. More definitive investigation is required before PI-cycle dysfunction can be considered specific to bipolar disorder.

Chemical-physical properties of lipoproteins in anorexia nervosa

BACKGROUND

Anorexia nervosa (AN), a psychosomatic disorder, has serious negative effects on multiple organs and systems of the human body. Anorexia nervosa usually runs a chronic course and is associated with significant morbidity and mortality. In order to elucidate the role played by lipids in AN, in the present study we compared the plasma lipid profile and the chemical-physical properties of lipoproteins obtained from subjects affected by AN.

MATERIALS AND METHODS

The study was performed on lipoproteins of AN subjects and of age-matched healthy subjects used as controls. We tested the susceptibility to oxidative stress in vitro, the fatty acid content, the fluidity using 2-dimethylamino-(6-lauroyl)-naphthalene (Laurdan) and 1,6-difenil-1,3,5-esatriene (DPH) probes.

RESULTS

Present results indicate that AN patients present a deep alteration of the composition and of chemical-physical properties in circulating lipoproteins, even in the absence of significant modifications to clinical metabolic parameters. A significantly decreased body mass index (BMI) was found in AN patients in comparison with controls. Anorexia nervosa patients showed a significant modification of phospholipids to protein ratio and a significantly increased percentage of unsaturated fatty acids compared with control subjects as well as a decreased fluidity, a significantly increased percentage of liquid-crystalline phase in VLDL, and a significantly reduced susceptibility to oxidative stress, more pronounced in LDL.

CONCLUSIONS

These results confirm the hypothesis that anorexia is accompanied by changes of lipid metabolism in the central nervous system (CNS).

Dietary polyunsaturated fatty acids and anorexia nervosa: is there a link?

There has been little research examining the link between dietary fat intake and the symptoms and consequences of anorexia nervosa. In this selective literature review, the potential significance of poly-unsaturated fatty acids is discussed. It is hypothesised that dietary restriction causes essential fatty acid deficiencies and poly-unsaturated fatty acid abnormalities, which might contribute to the physical and mental symptoms and the maintenance of the disorder. The examination of epidemiology, symptoms, co-morbidity, and consequences suggest that poly-unsaturated fatty acid and phospholipid abnormalities are significant in anorexia nervosa. This will be an important area for future research, and may lead to the development of new interventions.

Neuroimaging studies in eating disorders

The understanding of the eating disorders (EDs) anorexia (AN) and bulimia nervosa (BN) has undergone remarkable advancements in the past decade. Most studies that have been done in AN show brain gray and white matter volume loss during the ill state that, at least in part, remit with recovery. Similar patterns occur for brain phospholipids assessed using magnet resonance spectroscopy (MRS). Imaging studies have been used to provide functional information regarding serotonin neuroreceptor dynamics, regional cerebral blood flow, or cerebral glucose metabolism. Such studies have implicated cingulate, frontal, temporal, and parietal regions in AN. Investigators have found that challenges such as food and body image distortions may activate some of these regions, raising the possibility that such studies may shed light on puzzling AN symptoms, such as body image distortions or extremes of appetitive behaviors. Emerging data suggest these disturbances persist after recovery from AN, suggesting the possibility that these are traits that may create a vulnerability to develop an ED. While fewer studies have been done in BN or binge eating disorder, there may be disturbances of serotonin metabolism in similar brain regions. Taken together, these findings give promise for future investigations with the hope of delineating brain pathways that contribute to the etiology of EDs

Proton magnetic resonance spectroscopy in anorexia nervosa: correlations with cognition

The aim of this study was to investigate the relationship between cognitive impairment and cerebral metabolites in patients with anorexia nervosa (AN). N-acetylaspartate (NAA), creatine/phosphocreatine (Cr), choline-containing compounds, glutamate/glutamine (Glx) and myoinositol were measured by proton magnetic resonance spectroscopy (H-MRS) of the left prefrontal cortex. Compared with healthy controls, AN patients displayed a significantly poorer performance in verbal learning and in attentional and executive tasks. Performance in the divided attention task was correlated with NAA and Cr in the dorsolateral prefrontal cortex, while executive functioning and depressive symptomatology were associated with Glx levels in the anterior cingulate. Our results provide evidence for cognitive impairment in AN patients which is associated with cerebral metabolism in the prefrontal cortex.

Reduced 5-HT2A receptor binding after recovery from anorexia nervosa

BACKGROUND

Several lines of evidence suggest that a disturbance of serotonin neuronal pathways may contribute to the pathogenesis of anorexia nervosa (AN). This study applied positron emission tomography (PET) to investigate the brain serotonin 2A (5HT2A) receptor, which could contribute to disturbances of appetite and behavior in AN.

METHODS

To avoid the confounding effects of malnutrition, we studied 16 women recovered from AN (REC AN, >1 year normal weight, regular menstrual cycles, no bingeing or purging) compared with 23 healthy control women (CW) using [18F]altanserin, a specific 5-HT2A receptor antagonist on PET imaging.

RESULTS

REC AN women had significantly reduced [18F]altanserin binding relative to CW in mesial temporal (amygdala and hippocampus), as well as cingulate cortical regions. In a subset of subjects (11 CW and 16 REC AN), statistical parametric mapping (SPM) confirmed reduced mesial temporal cortex 5HT2A receptor binding and, in addition, showed reduced occipital and parietal cortex binding.

CONCLUSIONS

This study extends research suggesting that altered 5-HT neuronal system activity persists after recovery from AN and may be related to disturbances of mesial temporal lobe function. Altered 5-HT neurotransmission after recovery also supports the possibility that this may be a trait-related disturbance that contributes to the pathophysiology of AN.

Breakdown of choline-containing phospholipids in rat brain during severe weight loss

Recent investigations in human anorectic patients indicated changes of brain choline metabolism. We used starved rats to investigate possible changes of brain choline metabolites during severe weight loss. Reductions of body weight by 15, 30 and 45% resulted in significant decreases of cerebral phosphatidylcholine and sphingomyelin levels. Concomitantly, the brain tissue content of glycerophosphocholine was increased while phosphocholine and free choline were unchanged. We conclude that severe weight loss is accompanied by phospholipase activation and breakdown of choline-containing phospholipids in the brain.

The integration of primary anorexia nervosa and obsessive-compulsive disorder

This paper explores the relationship between primary anorexia nervosa (PAN) and obsessive-compulsive disorder (OCD) in both their concomitant and their sequential presentation. Their clinical descriptions demonstrate the presence of obsessionality and compulsiveness that seem to interface during their course and overlap in their symptomatologies has been noted for over sixty years. However, recent research in this regard is scant. Commonalities in pathophysiology indicate disturbances in neurotransmitters, notably serotonin. Biological challenges have failed to establish a definitive correlation with PAN and OCD, whether in combination or individually. We may postulate that, with limitations, they share some anatomical pathways. The areas affected are the amygdala, cingulum and orbito-frontal cortex. Few studies, however, have been devoted to the treatment of concomitant PAN and OCD.

Season of birth in females with anorexia nervosa in Northeast Scotland

OBJECTIVE

To determine whether patients with anorexia nervosa exhibit an abnormal pattern in their season of birth.

METHOD

Case records of female patients presenting to secondary services in Northeast Scotland from 1965 to 1997 who received a clinical diagnosis of anorexia nervosa were examined. The months of birth of the 446 anorexic patients with a confirmed diagnosis were compared with 5,766 female control subjects born locally in 1951, 1961, 1971, and 1981.

RESULTS

Patients with anorexia nervosa had an excess of births in the first 6 months of the year (p =.013). The greatest excess was from March to June.

DISCUSSION

This provides further evidence that birth dates of anorexics peak in the late spring and early summer. There are parallels with the epidemiology of schizophrenia. The evidence suggests that a seasonally fluctuating factor, most plausibly an intrauterine effect of common infectious agents during the winter months, is of etiological significance.

Clinical implications of brain imaging in eating disorders

Imaging studies have greatly improved the understanding of the pathology and physiology of psychiatric disorders, such as schizophrenia, affective disorders, obsessive-compulsive disorder, and Tourette syndrome. In the past few years, several neuroimaging studies have concentrated on patients with eating disorders. Although the number of studies is small compared with studies of other psychiatric disorders, the results are beginning to highlight potential areas in the brain that may lead to a better understanding of these disorders. Much research still is needed, and replication of results across centers is needed. The brain is an extremely complex organ; that eating disorders are a result of abnormalities in one specific area of the brain is unlikely. More likely is that several components of the brain have a role, including cortex and subcortical regions and involvement of several neurochemical pathways and circuits within the brain. Further studies are needed in this exciting development of research about eating disorders.

Are there specific disabilities of number processing in adolescent patients with Anorexia nervosa? Evidence from clinical and neuropsychological data when compared to morphometric measures from magnetic resonance imaging

The cerebral effect of the loss of body weight in Anorexia nervosa (A.n.)--the so-called 'pseudoatrophy'-- is well known and confirmed by several neuroimaging studies. Another subject of intensive research has been whether A.n. leads to specific cognitive impairments, especially of intelligence. However, there are no previous studies on the relations between the cerebral changes, intelligence performance, and disorders of number processing in adolescent patients with A.n. We examined n = 18 inpatients with A.n. (means at admission: age 14.5 years, SD 1.59; BMI 14.9, SD 1.36), diagnosed according to ICD-10 criteria at three different timepoints: at admission to treatment (T1), with 50 % restoration of their normal weight (T2), and with normal weight (T3). At each timepoint, a cerebral MRI scan was obtained. Based on the MRI we determined the volume of the external and internal cerebrospinal fluid cavities, fissures of Sylvius, the surface of mesencephalon and pons, and surface and length of the Corpus callosum. At T1 and T3, a neuropsychological examination was conducted including tests of the general fluid ability and general cristallized ability of intelligence (CFT-20), as well as tests of vocabulary and number processing. The same instruments were given to a group of matched controls (means: age 15.8 years, SD 1.57; BMI 20.5, SD 2.3) at one timepoint. We could show a significant volume difference of the lateral ventricles and the fissure of Sylvius between patients at T, and controls, which abaded with the patient's weight restoration. But a significant surface deficit of the mesencephalon, and less pronounced in the pons, persisted to T3 in patients when compared to controls, suggesting a selectivity of the cerebral changes in A.n. The neuropsychological examinations revealed significant changes in test performance for both the general intelligence test and number processing. At T1 the number processing performance was significantly lower in patients when compared to controls. However, when the patients had restored their normal body weight, we found 2.02 % with a 'severe disorder of arithmetic skills' and 4.45 % with a 'functional disorder of arithmetic skills'. This combined prevalence of 6.47 % of patients with a subnormal arithmetic performance is analogous to that in the normal population.

The prevention of eating disorders: a review of the research on risk factors with implications for practice

TOPIC

Eating disorders are a significant health problem among children and adolescents. A synthesis of recent research findings on the risk factors for eating disorders describes prevention strategies for practice.

PURPOSE

To present research findings on risk factors for eating disorders that specifically relate to prevention for advanced practice. Current investigations are reviewed and critiqued for biologic, psychological, family, and sociocultural risk factors. A critique of the research and findings from important studies describes strategies for prevention of eating disorders for advanced practice.

SOURCES

Published literature and clinical and research expertise of the author.

CONCLUSIONS

Identifiable risk factors for eating disorders are found in children as well as adolescents. Findings from risk factor research provide the advanced practice nurse strategies for prevention of eating disorders. Few prevention programs exist; even fewer have been tested. An important clinical and research focus for advanced practice nurses is the prevention of eating disorders.