(PS6-84) Kappa opioid receptor availability and interoceptive awareness: Investigating links across disordered eating behaviors

Abstract Text:

Background: Interoception, the ability to perceive internal bodily states, relies on the thalamus, insular cortex, amygdala, anterior cingulate cortex (ACC), and frontal brain regions. Interoceptive deficits are implicated in disordered eating behaviors (DEB) and are considered to be transdiagnostic features of eating disorders (ED). Crucially, EDs are difficult to treat. Many individuals with ED do not respond to available psychopharmacological interventions, highlighting the need for more effective treatments for ED and DEB. Understanding the neurobiological mechanisms underlying interoceptive deficits may help identify a novel treatment target. A potential target is the kappa opioid receptor (KOR), which plays a role in stress, emotion regulation, and reward processing, all of which are relevant to DEB. However, its relationship with interoception is underexplored. Using [11C]EKAP PET imaging, this study presents a preliminary examination of relationships between KOR availability, interoceptive awareness (IA), and DEB. First, we hypothesized that lower KOR availability, reflecting increased receptor activity due to stress-triggered dynorphin release, will be associated with reduced IA (aspects of emotional awareness; attention regulation; body trust). Second, we hypothesized that this relationship will be stronger in individuals with DEB, as greater emotional and stress-related demands may amplify KOR’s impact on interoceptive processing.

Methods: 20 individuals (65% female, Mage = 31.7; diagnoses of borderline personality disorder, post-traumatic stress disorder, or healthy controls) participated in an [11C]EKAP PET scan and MRI (Outcome measure = volume of distribution [VT]). Regions of interest included amygdala, thalamus, ACC, insula, and frontal regions, averaged to create a KOR circuit value. IA was assessed with subscales of the Multidimensional Assessment of Interoceptive Awareness (MAIA-2). The high DEB group included those above the clinical cut-off on the Eating Disorders Examination Questionnaire (> 2.8; n=5).

Results: In the full sample, moderate, although not statistically significant, positive correlations were observed between KOR availability and Attention Regulation (r(15)=.39, p=.122) and Trust (r(15)=.42, p=.094). KOR availability was not correlated with Emotional Awareness (p=.897). The high DEB group exhibited lower Trust scores (t(13)=-2.49, p=.013) and lower KOR availability (t(10)=-2.35, p=.040) than the low DEB group.

Discussion: The study found a trend-level positive correlation between KOR availability and body trust, suggesting that greater KOR availability may be associated with higher trust in bodily signals. However, future analyses in a larger sample is needed to determine whether this relationship would reach statistical significance. Additionally, individuals with higher DEB exhibited lower KOR availability and reduced body trust, suggesting a potential link between opioid system function and interoceptive deficits in individuals with DEB. Clinically, KOR antagonists and interoception-focused therapies may help improve body trust in individuals with DEB. Future work should explore KOR, IA, and DEB in larger samples with formal ED diagnoses.