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

Simon Maier,Andreas Joos,Ludger Tebartz Van Elst,Lukas Holovics,Michael Dacko,Almut Zeeck,Armin Hartmann,Evgeniy Perlov,Dominique Endres,Kathrin Nickel,Derek Spieler,Alina Kukies,Thomas Lange

doi:10.3390/jcm9051292

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.

Highlights

Patients with anorexia nervosa (AN) persistently restricted their food intake because of severe weight concerns and body image disturbance
This study examined female adults with AN, female adults who had recovered (REC) from AN, and healthy controls (HC) via magnetic resonance spectroscopy (MRS), which targeted the insular cortex
We found decreased NAA signals in the anterior insular cortex of women with AN and lower NAA and Glx concentrations in patients with stronger AN symptoms

Summary

Introduction

Patients with anorexia nervosa (AN) persistently restricted their food intake because of severe weight concerns and body image disturbance. AN mainly affects young women [1,2,3] and has the highest mortality rate of all mental disorders [4,5], while only about half of such patients fully recover [1,2]. NAA is relatively abundant in healthy neuronal tissue and is often used as a marker for neuronal integrity and density [6]. It has been detected in oligodendrocytes and myelin [7,8], and it is synthesized in the mitochondria. NAA signal differences have been reported in various studies on AN, the results were inconsistent regarding a diminished or elevated NAA level [9,10,11,12,13] (see Table 1)

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Results

Discussion

Conclusion