Structural hippocampal alterations, perceived stress, and coping deficiencies in patients with anorexia nervosa

The Impact of Age on Gray Matter Volume Reduction in Anorexia Nervosa: A Systematic Review

Objective

This study examines the relationship between gray matter (GM) volume reduction and age in individuals with Anorexia Nervosa (AN). Specifically, it investigates whether the magnitude and direction of GM volume differences between AN and healthy controls remain consistent across a range of age groups. Additionally, we reviewed regional GM alterations reported in the literature to characterize unique regional brain profiles observed in AN. By synthesizing neuroimaging studies and mean-age stratified analysis, this work provides insights into the possible impact aging can have on GM reduction in patients with AN.

Methods

Systematic review and meta-analysis were conducted using MRI-based neuroimaging studies assessing GM volume in AN patients and controls. A primary meta-analysis was run for all feasible studies combined, followed by a stratified analysis approach examining "younger mean-age" studies and "older mean-age" studies separately. Random effects models were used for the meta-analysis. Meta-regression was used to determine the influence of age on GM volume differences and was controlled for the body mass index to minimize the confounding effect recovery status has on the GM differences between groups. Regional GM alterations were reviewed and discussed.

Results

44 studies, including 1391 individuals with AN and 1566 healthy controls, were included in the primary meta-analysis. No substantial heterogeneity was found across studies. Compared to their respective control groups, the younger-age studies, defined by studies with AN subject of mean age less than 18, exhibited greater significant GM volume loss (-5.39, 95% CI: -7.76 to -3.01, p<0.05) compared to older-age studies (-3.09, 95% CI: -4.16 to -2.03, p<0.05). Meta-regression subgroup results suggest that having older age in AN subjects is linked to less severe GM reduction relative controls. Our review of the regional GM literature reveals that alterations in the hippocampus, amygdala, and precuneus of the medial parietal lobe were more frequently reported than other brain regions in AN. In these regions, we also noticed that younger individuals with AN had more consistent volume reductions across studies, whereas studies with older AN showed greater variability.

Conclusion

Grey matter volume loss in AN is more pronounced in younger patients even after controlling for the effect of the recovery status. Having older age appears to contribute to less deficit in brain volume loss in AN, suggesting a protective mechanism underlying GM alteration in older AN patients. These findings reinforce the need for early intervention and prolonged recovery support and emphasize the need to develop lifespan-specific disorder management approaches. Future research should explore long-term GM recovery trajectories and the aging effect on GM alteration for older patients to refine strategies for neuroprotection in AN.

Hunger Games: A Modern Battle Between Stress and Appetite

Stress, an evolutionarily adaptive mechanism, has become a pervasive challenge in modern life, significantly impacting feeding-relevant circuits that play a role in the development and pathogenesis of eating disorders (EDs). Stress activates the hypothalamic-pituitary-adrenal (HPA) axis, disrupts specific neural circuits, and dysregulates key brain regions, including the hypothalamus, hippocampus, and lateral septum. These particular structures are interconnected and key in integrating stress and feeding signals, modulating hunger, satiety, cognition, and emotional coping behaviors. Here we discuss the interplay between genetic predispositions and environmental factors that may exacerbate ED vulnerability. We also highlight the most commonly used animal models to study the mechanisms driving EDs and recent rodent studies that emphasize the discovery of novel cellular and molecular mechanisms integrating stress and feeding signals within the hippocampus-lateral septum-hypothalamus axis. In this review, we discuss the role of gut microbiome, an emerging area of research in the field of EDs and unanswered questions that persist and hinder the scientific progress, such as why some individuals remain resilient to stress while others become at high risk for the development of EDs. We finally discuss the need for future research delineating the impact of specific stressors on neural circuits, clarifying the relevance and functionality of hippocampal-septal-hypothalamic connectivity, and investigating the role of key neuropeptides such as CRH, oxytocin, and GLP-1 in human ED pathogenesis. Emerging tools like single-cell sequencing and advanced human imaging could uncover cellular and circuit-level changes in brain areas relevant for feeding in ED patients. Ultimately, by integrating basic and clinical research, science offers promising avenues for developing personalized, mechanism-based treatments targeting maladaptive eating behavior for patients suffering from EDs.

Associations between parental rearing style and amygdala and hippocampal subfield abnormalities in drug-naive females with anorexia nervosa

BACKGROUND

Altered volumes in the hippocampus and amygdala have been linked to anorexia nervosa (AN). This study aimed to investigate amygdala and hippocampal subfields volume abnormalities in AN patients, and their associations with parental rearing practices and clinical psychological characteristics.

METHODS

This study included twenty-nine drug-naive females with AN from West China Hospital of Sichuan University, China, and fifty-nine age- and gender-matched healthy controls (HCs) recruited through advertisement. All participants underwent T1-weighted imaging. Amygdala and hippocampal subfields volume was calculated using FreeSurfer 7.0. The Core Self-Evaluation Scale (CSES) and Rosenberg Self-Esteem Scale (RSES) were used to assess the psychological characteristics of AN patients. The Egna Minnen av Barndoms Uppfostran (EMBU) was employed to evaluate parental rearing practices. Group differences in brain volumes were analyzed with covariates like age and total intracranial volume (TIV). Partial correlation analysis explored the correlations between brain region volumes and clinical psychological characteristics.

RESULTS

AN patients exhibited lower RSES and CSES scores, and more adverse parental rearing style than healthy norms. After adjusting for covariates, AN patients showed decreased gray matter volume (GMV) in the left medial (Me) and cortical (Co) nucleus, as well as in the right hippocampal-amygdala transition area (HATA). GMV in the left Me was correlated with years of education among HCs but not among AN patients. GMV in the right HATA was positively correlated with paternal penalty and severity, as well as maternal overinterference.

CONCLUSION

This study supports structure abnormalities in amygdala and hippocampus in AN patients and suggests that parental rearing practices may be associated with hippocampal abnormalities, potentially contributing to the pathophysiology of AN. Addressing appropriate parental rearing styles may offer a positive impact on AN.

Longitudinal changes in brain-derived neurotrophic factor (BDNF) but not cytokines contribute to hippocampal recovery in anorexia nervosa above increases in body mass index

BACKGROUND

Physical sequelae of anorexia nervosa (AN) include a marked reduction in whole brain volume and subcortical structures such as the hippocampus. Previous research has indicated aberrant levels of inflammatory markers and growth factors in AN, which in other populations have been shown to influence hippocampal integrity.

METHODS

Here we investigated the influence of concentrations of two pro-inflammatory cytokines (tumor necrosis factor-alpha [TNF-α] and interleukin-6 [IL-6]) and brain-derived neurotrophic factor (BDNF) on the whole hippocampal volume, as well as the volumes of three regions (the hippocampal body, head, and tail) and 18 subfields bilaterally. Investigations occurred both cross-sectionally between acutely underweight adolescent/young adult females with AN (acAN; n = 82) and people recovered from AN (recAN; n = 20), each independently pairwise age-matched with healthy controls (HC), and longitudinally in acAN after partial renourishment (n = 58). Hippocampal subfield volumes were quantified using FreeSurfer. Concentrations of molecular factors were analyzed in linear models with hippocampal (subfield) volumes as the dependent variable.

RESULTS

Cross-sectionally, there was no evidence for an association between IL-6, TNF-α, or BDNF and between-group differences in hippocampal subfield volumes. Longitudinally, increasing concentrations of BDNF were positively associated with longitudinal increases in bilateral global hippocampal volumes after controlling for age, age2, estimated total intracranial volume, and increases in body mass index (BMI).

CONCLUSIONS

These findings suggest that increases in BDNF may contribute to global hippocampal recovery over and above increases in BMI during renourishment. Investigations into treatments targeted toward increasing BDNF in AN may be warranted.

Rare CRHR2 and GRM8 variants identified as candidate factors associated with eating disorders in Japanese patients by whole exome sequencing

Eating disorders (EDs) are a type of psychiatric disorder characterized by pathological eating and related behavior and considered to be highly heritable. The purpose of this study was to explore rare variants expected to display biological functions associated with the etiology of EDs. We performed whole exome sequencing (WES) of affected sib-pairs corresponding to disease subtype through their lifetime and their parents. From those results, rare single nucleotide variants (SNVs) concordant with sib-pairs were extracted and estimated to be most deleterious in the examined families. Two non-synonymous SNVs located on corticotropin-releasing hormone receptor 2 (CRHR2) and glutamate metabotropic receptor 8 (GRM8) were identified as candidate disease susceptibility factors. The SNV of CRHR2 was included within the cholesterol binding motif of the transmembrane helix region, while the SNV of GRM8 was found to contribute to hydrogen bonds for an α-helix structure. CRHR2 plays important roles in the serotoninergic system of dorsal raphe nuclei, which is involved with feeding and stress-coping behavior, whereas GRM8 modulates glutamatergic neurotransmission. Moreover, GRM8 modulates glutamatergic neurotransmission, and is also considered to have effects on dopaminergic and adrenergic neurotransmission. Thus, identification of rare and deleterious variants in this study is expected to increase understanding and treatment of affected individuals. Further investigation regarding the biological function of these variants may provide an opportunity to elucidate the pathogenesis of EDs.

Differential longitudinal changes of hippocampal subfields in patients with anorexia nervosa

BACKGROUND

Anorexia nervosa (AN) is a mental disorder characterized by dietary restriction, fear of gaining weight, and distorted body image. Recent studies indicate that the hippocampus, crucial for learning and memory, may be affected in AN, yet subfield-specific effects remain unclear. We investigated hippocampal subfield alterations in acute AN, changes following weight restoration, and their associations with leptin levels.

METHODS

T1-weighted magnetic resonance imaging scans were processed using FreeSurfer. We compared 22 left and right hemispheric hippocampal subfield volumes cross-sectionally and longitudinally in females with acute AN (n = 165 at baseline, n = 110 after partial weight restoration), healthy female controls (HCs; n = 271), and females after long-term recovery from AN (n = 79) using linear models.

RESULTS

We found that most hippocampal subfield volumes were significantly reduced in patients with AN compared with HCs (~-3.9%). Certain areas such as the subiculum exhibited no significant reduction in the acute state of AN, while other areas, such as the hippocampal tail, showed strong decreases (~-9%). Following short-term weight recovery, most subfields increased in volume. Comparisons between participants after long-term weight-recovery and HC yielded no differences. The hippocampal tail volume was positively associated with leptin levels in AN independent of body mass index.

CONCLUSIONS

Our study provides evidence of differential volumetric differences in hippocampal subfields between individuals with AN and HC and almost complete normalization after weight rehabilitation. These alterations are spatially inhomogeneous and more pronounced compared with other major mental disorders (e.g. major depressive disorder and schizophrenia). We provide novel insights linking hypoleptinemia to hippocampal subfield alterations hinting towards clinical relevance of leptin normalization in AN recovery.

A meta-analytic investigation of grey matter differences in anorexia nervosa and autism spectrum disorder

Recent research reports Anorexia Nervosa (AN) to be highly dependent upon neurobiological function. Some behaviours, particularly concerning food selectivity are found in populations with both Autism Spectrum Disorder (ASD) and AN, and there is a proportionally elevated number of anorexic patients exhibiting symptoms of ASD. We performed a systematic review of structural MRI literature with the aim of identifying common structural neural correlates common to both AN and ASD. Across 46 ASD publications, a meta‐analysis of volumetric differences between ASD and healthy controls revealed no consistently affected brain regions. Meta‐analysis of 23 AN publications revealed increased volume within the orbitofrontal cortex and medial temporal lobe, and adult‐only AN literature revealed differences within the genu of the anterior cingulate cortex. The changes are consistent with alterations in flexible reward‐related learning and episodic memory reported in neuropsychological studies. There was no structural overlap between ASD and AN. Findings suggest no consistent neuroanatomical abnormality associated with ASD, and evidence is lacking to suggest that reported behavioural similarities between those with AN and ASD are due to neuroanatomical structural similarities.

Findings related to neuroanatomical structure in AN/ASD demonstrate overlap and require revisiting.

Meta‐analytic findings show structural increase/decrease versus healthy controls (LPFC/MTL/OFC) in AN, but no clusters found in ASD.

The neuroanatomy associated with ASD is inconsistent, but findings in AN reflect condition‐related impairment in executive function and sociocognitive behaviours.

Neuroimaging of psychiatric disorders

Psychiatry remains the only medical specialty where diagnoses are still based on clinical syndromes rather than measurable biological abnormalities. As imaging technology and analytical methods evolve, it is becoming clear that subtle but measurable radiological characteristics exist and can be used to experimentally classify psychiatric disorders, predict response to treatment and, hopefully, develop new, more effective therapies. This review highlights advances in neuroimaging modalities that are now allowing assessment of brain structure, connectivity and neural network function, describes technical aspects of the most promising methods, and summarizes observations made in some frequent psychiatric disorders.

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.

Hippocampal volume, function, and related molecular activity in anorexia nervosa: A scoping review

INTRODUCTION

Anorexia nervosa (AN) is a serious and persistent eating disorder, characterized by severe dietary restriction and weight loss, with a third of patients developing a  severe-enduring form. The factors contributing to this progression are poorly understood, although there is evidence for impairments in neural structures such as the hippocampus, an area particularly affected by malnutrition and chronic stress.

AREAS COVERED

This study aimed to map the evidence for alterations in hippocampal volume, function, and related molecular activity in anorexia nervosa. PubMed, PsycINFO, and Web of Science were searched for studies related to hippocampal function and integrity using a range of methodologies, such as neuropsychological paradigms, structural and functional magnetic resonance imaging, and analysis of blood components.

EXPERT OPINION

Thirty-nine studies were included in this review. The majority were neuroimaging studies, which found hippocampus-specific volumetric and functional impairments. Neuropsychological studies showed evidence for a specific memory and learning impairments. There was some evidence for molecular abnormalities (e.g. cortisol), although these were few studies. Taken together, our review suggests that the hippocampus might be a particular region of interest when considering neurobiological approaches to understanding AN. These findings warrant further investigation and may lead to novel treatment approaches.

Hippocampal volumes in anorexia nervosa at different stages of the disorder

INTRODUCTION

Hippocampus is involved in a range of cognitive and behavioural processes, and its volume has been found to be reduced in different psychiatric disorders. The present study aims at exploring hippocampal volumes in anorexia nervosa (AN) at different stages of the disorder (a few months after onset, more than 1 year after onset and after recovery).

METHODS

Two samples were included in the present study. The first was composed of 58 patients (38 with present AN, 20 full recovered from AN) and 38 age-matched healthy women (HW); the second, recruited at a different site, included 20 patients with AN and 16 HW. Hippocampal volume has been estimated using an automated segmentation algorithm. Age, site of scanning and total intracranial volumes were used as covariates in the statistical analyses.

RESULTS

AN patients showed a reduced hippocampal volume in comparison to HW, with no substantial differences between patients with recent onset and those with a longer duration of illness. Among patients, hippocampal volumes correlated with body mass index, anxiety and drive for thinness.

DISCUSSION

Our findings suggest an early role of malnutrition in the morphologic alterations of the hippocampus in AN and a possible role of this brain structure in mediating specific psychopathological traits.

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.

Anorexia increases microglial density and cytokine expression in the hippocampus of young female rats

Anorexia by osmotic dehydration is an adaptive response to hypernatremia and hyperosmolaemia induced by ingestion of a hypertonic solution. Dehydration-induced anorexia (DIA) reproduces weight loss and avoidance of food, despite its availability. By using this model, we previously showed increased reactive astrocyte density in the rat dorsal hippocampus, suggesting a pro-inflammatory environment where microglia may play an important role. However, whether such anorexic condition increases a pro-inflammatory response is unknown. The aim of this study was to test if DIA increases microglial density in the dorsal hippocampus, as well as the expression of pro-inflammatory cytokines tumor necrosis factor alpha (TNF-α), interleukin 6 (IL-6) and interleukin 1 beta (IL-1β) in the hippocampus of young female rats. Our results showed that DIA significantly increased microglial density in CA2-CA3 and dentate gyrus (DG) but not in CA1. However, forced food restriction (FFR) only increased microglial density in the DG. Accordingly, the activated/resting microglia ratio was significantly increased in CA2-CA3 and DG, in DIA and FFR groups. Finally, western blot analysis showed increased expression of IBA1, TNF-α, IL-6 and IL-1β in the hippocampus of both experimental groups. We conclude that anorexia triggers increased reactive microglial density and expression of TNF-α, IL-6 and IL-1β; this environment may result in hippocampal neuroinflammation.

Body image disturbances, fear and associations with the amygdala in anorexia nervosa

Background

Anorexia nervosa (AN) is a severe illness with a high mortality rate which mainly affects young women. Studies found a localized volume loss of the amygdala in patients with AN, a brain region responsible for affective responses. Patients with AN were found to have body image distortions, and suffer from the comorbid disorders depression, anxiety disorder, and obsession. Therefore, the purpose of this study was to analyze a possible connection between comorbidities, body image disturbances, and the volume of the amygdala in patients with AN.

Methods

In this study 21 females suffering from restrictive-type AN and 21 age-matched normal controls (NC) were tested. Demographic data as well as body image perceptions and comorbidities were assessed. Volumes of cortical structures were measured with a magnetic resonance (MR) scanner. Analyses of variance were conducted to analyze group differences, and correlations between the volume of the amygdala and comorbidities and body image perceptions were calculated.

Results

The results showed a significantly lower grey matter volume in the amygdala in AN patients compared to the NC. Persons with AN showed more body image disturbances and suffered more often from depression, and phobias than NC. The volume of the amygdala showed a non-significant mid-level association with phobia and with uncertainty concerning their body in AN patients.

Conclusion

The study indicates that phobic anxiety and body image in patients with AN could be related to the volume of the amygdala. The results contribute to a better understanding of the pathophysiology of the disease.

Hippocampal subfields in adolescent anorexia nervosa

Patients with anorexia nervosa (AN) exhibit volume reduction in cerebral gray matter (GM), and several studies report reduced hippocampus volume. The hippocampal subfields (HS) are functionally and structurally distinct, and appear to respond differently to neuropathology. The aim of this study was to investigate HS volumes in adolescent females with restrictive AN compared to a healthy age-matched control group (HC). The FreeSurfer v6.0 package was used to extract brain volumes, and segment HS in 58 female adolescents (AN = 30, HC = 28). We investigated group differences in GM, white matter (WM), whole hippocampus and 12 HS volumes. AN patients had significantly lower total GM and total hippocampal volume. No group difference was found in WM. Volume reduction was found in 11 of the 12 HS, and most results remained significant when adjusting for global brain volume reduction. Investigations of clinical covariates revealed statistically significant relationships between the whole hippocampus, several HS and scores on depression and anxiety scales in AN. Results from this study show that young AN patients exhibit reduced volume in most subfields of the hippocampus, and that this reduction may be more extensive than the observed global cerebral volume loss.

The potential of calibrated fMRI in the understanding of stress in eating disorders

Eating disorders (ED), including Anorexia Nervosa (AN), Bulimia Nervosa (BN), and Binge Eating Disorder (BED), are medically dangerous psychiatric disorders of unknown etiology. Accumulating evidence supports a biopsychosocial model that includes genetic heritability, neurobiological vulnerability, and psychosocial factors, such as stress, in the development and maintenance of ED. Notably, stress hormones influence appetite and eating, and dysfunction of the physiological stress response has been implicated in ED pathophysiology. Stress signals also appear associated with food reward neurocircuitry response in ED, providing a possible mechanism for the role of stress in appetite dysregulation. This paper provides a review of some of the interacting psychological, behavioral, physiological, and neurobiological mechanisms involved in the stress response among individuals with ED, and discusses novel neuroimaging techniques to address potential physiological confounds of studying neural correlates of stress in ED, such as calibrated fMRI.

Inflammatory Markers in Anorexia Nervosa: An Exploratory Study

Inflammation has been suggested to play a pathophysiological role in anorexia nervosa (AN). In this exploratory cross-sectional study, we measured serum concentrations of 40 inflammatory markers (including cytokines, chemokines, and adhesion molecules) and brain-derived neurotrophic factor (BDNF) in people with AN (n = 27) and healthy controls (HCs) (n = 13). Many of these inflammatory markers had not been previously quantified in people with AN. Eating disorder (ED) and general psychopathology symptoms were assessed. Body mass index (BMI) and body composition data were obtained. Interleukin (IL)-6, IL-15, and vascular cell adhesion molecule (VCAM)-1 concentrations were significantly elevated and concentrations of BDNF, tumor necrosis factor (TNF)-β, and vascular endothelial growth factor (VEGF)-A were significantly lower in AN participants compared to HCs. Age, BMI, and percentage body fat mass were identified as potential confounding variables for several of these inflammatory markers. Of particular interest is that most of the quantified markers were unchanged in people with AN, despite them being severely underweight with evident body fat loss, and having clinically significant ED symptoms and severe depression and anxiety symptoms. Future research should examine the replicability of our findings and consider the effect of additional potential confounding variables, such as smoking and physical activity, on the relationship between AN and inflammation.

Decreased feedback learning in anorexia nervosa persists after weight restoration

OBJECTIVE

Anorexia Nervosa (AN) is a serious disorder, with a mortality rate the highest of any psychiatric illness. It is notoriously challenging to treat and mechanisms of illness are not well understood. Reward system abnormalities have been proposed across theoretical models of the persistence of AN. Feedback learning is an important component of how reward systems shape behavior and we hypothesized that individuals with AN would show poorer learning from feedback.

METHODS

We administered the acquired equivalence task to measure both learning from incremental feedback and generalization of that learning to novel stimuli. Participants were individuals with AN (n = 36) before and after intensive weight restoration treatment and healthy comparison participants (HC, n = 26) tested twice. Performance was assessed as accuracy during the Learning and Test phases, for both trained and novel stimuli. The relationship between task performance and eating disorder severity at baseline was also assessed.

RESULTS

Both before and after treatment, individuals with AN showed reduced learning from feedback in the Learning phase (F_3,180  = 2.75, p = .048) and lower accuracy during the Test phase (F_1,60  = 4.29, p = .043), as compared with HC. Individuals with AN did not differ from HC in accuracy for novel stimuli (F_1,60  = 1.04, p = .312), indicating no deficit in generalization. Decreased acquisition of feedback learning was associated with longer illness duration and with greater eating disorder symptom severity at baseline.

CONCLUSIONS

Individuals with AN show reduced learning from feedback or reinforcement, which may contribute to difficulties in changing maladaptive behaviors.

VIDEOFLUOROSCOPIC EVALUATION OF SWALLOWS IN ANOREXIA NERVOSA

BACKGROUND

There are some studies in the literature about the feeding behavior and masticatory process in patients with feeding disorders; however, it is not very well known if there are alterations in oral-pharyngeal swallowing dynamics in subjects with anorexia nervosa.

OBJECTIVE

To evaluate the oral and pharyngeal bolus transit in patients with anorexia nervosa.

METHODS

The study was conducted with 8 individuals clinically diagnosed and in treatment for restricting-type anorexia nervosa (seven women and one man), and 14 healthy individuals with no digestive or neurological symptoms (10 women, 4 men). Swallows were evaluated by videofluoroscopy with three swallows of 5 mL liquid bolus and three swallows of 5 mL paste bolus consistency, given in a random sequence. The participants were asked after each swallow about the sensation of the bolus passage.

RESULTS

In the analysis of oral-pharyngeal transit duration, the mean duration of pharyngeal transit with paste bolus in patients with anorexia was shorter than in healthy volunteers (P=0.02). In the duration of movement of the hyoid bone, longer movement was observed in anorexia than in healthy volunteers with liquid bolus (P=0.01). With liquid bolus, five (62.5%) patients and one (7.1%) control had sensation of the bolus passage (P<0.05).

CONCLUSION

There seems to be no important alterations of swallowing in subjects with anorexia nervosa, although the results suggest that pharyngeal transit has shorter duration than that seen in healthy volunteers and the hyoid movement duration is longer in patients than in healthy volunteers. Fast pharyngeal transit may be the cause of bolus transit perception in patients with anorexia nervosa.

Anorexia Reduces GFAP+ Cell Density in the Rat Hippocampus

Anorexia nervosa is an eating disorder observed primarily in young women. The neurobiology of the disorder is unknown but recently magnetic resonance imaging showed a volume reduction of the hippocampus in anorexic patients. Dehydration-induced anorexia (DIA) is a murine model that mimics core features of this disorder, including severe weight loss due to voluntary reduction in food intake. The energy supply to the brain is mediated by astrocytes, but whether their density is compromised by anorexia is unknown. Thus, the aim of this study was to estimate GFAP+ cell density in the main regions of the hippocampus (CA1, CA2, CA3, and dentate gyrus) in the DIA model. Our results showed that GFAP+ cell density was significantly reduced (~20%) in all regions of the hippocampus, except in CA1. Interestingly, DIA significantly reduced the GFAP+ cells/nuclei ratio in CA2 (−23%) and dentate gyrus (−48%). The reduction of GFAP+ cell density was in agreement with a lower expression of GFAP protein. Additionally, anorexia increased the expression of the intermediate filaments vimentin and nestin. Accordingly, anorexia increased the number of reactive astrocytes in CA2 and dentate gyrus more than twofold. We conclude that anorexia reduces the hippocampal GFAP+ cell density and increases vimentin and nestin expression.

Hippocampal subfield analysis in medication-naïve female patients with major depressive disorder

BACKGROUND

Hippocampal volume loss is known as the best-replicated finding of structural brain imaging studies on major depressive disorder (MDD). Several evidences suggest localized mechanisms of hippocampal neuroplasticity lead the brain imaging studies on the hippocampus and MDD to perform analyses in the subfield level. The aim of this study was to investigate the differences in total and subfield hippocampal volumes, between medication-naïve female MDD patients and healthy controls, through automated segmentation and volumetric methods.

METHODS

Twenty medication-naïve female patients diagnosed with MDD and 21 age-matched healthy controls, underwent T1-weighted structural magnetic resonance scanning. Total volumes of both hippocampi and subfield regions were calculated by the automated procedure for volumetric measures implemented in FreeSurfer and automated segmentation method by Van Leemput et al.

RESULTS

We observed patients to have significantly smaller volumes of the left hippocampus, subiculum, cornu ammonis 2-3, cornu ammonis 4-dentate gyrus, and right subiculum compared to healthy controls. There were no significant predictors for these subfield region volumes among the illness burden-related parameters including duration of illness, number of depressive episodes, severity of depressive symptoms and memory performances.

LIMITATIONS

Our findings relied on the data of only female participants.

CONCLUSIONS

We found significant volume reductions in several hippocampal subfield regions in medication-naïve female MDD patients. Our results are consistent with neurobiological evidences on hippocampal neuroplasticity in MDD, and replicate previous findings that suggest morphologic changes of hippocampal subfields in MDD patients.