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

Abstract

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.

A Neglected Topic in Neuroscience: Replicability of fMRI Results With Specific Reference to ANOREXIA NERVOSA

“…This study was part of a multimodal MRI study, which assessed structural, metabolic and other functional data [see, e.g., (31)(32)(33)(34)(35)(36)]. We replicated the aforementioned food paradigm with 31 AN and 27 NP.…”

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

“…Affected adolescents also demonstrated reduced relative concentrations of N-acetyl aspartate (NAA) in parieto-occipital WM, and NAA reductions have been observed in the anterior insula in adult women with AN (11). Although NAA is highly concentrated in grey matter (GM) and often considered a marker of neuronal density (12), it has various functional roles, including osmoregulation, myelin synthesis, neuron-glia signaling and glutamate turnover [reviewed by (13)].…”

Advances in Eating Disorders

“…To address this important health issue, the current Special Issue collected 21 articles examining the most recent and relevant scientific findings regarding advances in ED. The published articles comprised three reviews and 18 research articles focusing on different aspects, such as genetic [ 7 ] and epigenetic factors [ 8 ], biomarkers [ 9 ], comorbidity [ 10 , 11 , 12 , 13 , 14 ], clinical phenotypes [ 15 , 16 ], neurocognition [ 12 , 17 , 18 , 19 , 20 , 21 ], treatment predictors [ 22 ], and treatment models and therapeutic targets [ 19 , 23 , 24 , 25 , 26 , 27 ]. Altogether, these studies may provide increased knowledge about the pathogenesis, the risk factors, the maintenance factors, and the most appropriate treatments tools for ED.…”

“…The majority of research of this Special Issue focuses on neurosciences and EDs. There are several studies examining and reviewing a variety of relevant topics such as neuropsychology (especially executive functions) [ 12 , 17 ], structural alterations of the brain [ 18 ], neurometabolic alterations [ 20 ], neuroimaging studies, and the use and efficacy of invasive and non-invasive brain stimulation techniques [ 19 , 21 ]. Specifically, Mallorquí-Bagué et al [ 17 ] used electrophysiological techniques to explore emotion regulation and food craving regulation in patients with AN.…”

“…Research with neuroimaging techniques to assess morphological complexity of cortical brain structures from Collantoni et al [ 18 ] provided evidence that cortical fractal dimension (FD) may be a feasible and sensitive method to assess the negative effects of severity and duration of malnutrition in patients with AN. In addition, Maier et al [ 20 ] investigated the metabolic signals in the anterior insular cortex by means of magnetic resonance spectroscopy (MRS). Authors analyzed both acute and recovered patients with AN, as well as healthy controls, and found that metabolic alterations in patients with AN (i.e., lower NAA and Glx signals) seem to be state-related symptoms rather than traits.…”