The central nervous norepinephrine network links a diminished sense of emotional well-being to an increased body weight

Abstract

OBJECTIVES The neurobiological mechanisms linking obesity to emotional distress remain largely undiscovered. METHODS In this pilot study, we combined positron emission tomography, using the norepinephrine transporter (NET) tracer [11C]-O-methylreboxetine, with functional connectivity magnetic resonance imaging, the Beck depression inventory (BDI), and the impact of weight on quality of life-Lite questionnaire (IWQOL–Lite), to investigate the role of norepinephrine in the severity of depression (BDI), as well as in the loss of emotional well-being with body weight (IWQOL–Lite). RESULTS In a small group of lean-to-morbidly obese individuals (n = 20), we show that an increased body mass index (BMI) is related to a lowered NET availability within the hypothalamus, known as the brain’s homeostatic control site. The hypothalamus displayed a strengthened connectivity in relation to the individual hypothalamic NET availability to the anterior insula/frontal operculum, as well as the medial orbitofrontal cortex, assumed to host the primary and secondary gustatory cortex, respectively (n = 19). The resting-state activity in these two regions was correlated positively to the BMI and IWQOL–Lite scores, but not to the BDI, suggesting that the higher the resting-state activity in these regions, and hence the higher the BMI, the stronger the negative impact of the body weight on the individual’s emotional well-being was. CONCLUSIONS This pilot study suggests that the loss in emotional well-being with weight is embedded within the central norepinephrine network.

Emotional eating and in vivo norepinephrine transporter availability in obesity: A [11C]MRB PET pilot study

“…We did not replicate the recent finding of decreased thalamic NET availability in obesity, yet, this study sample has not been further characterized in terms of eating behavior. By investigating EE and NET availability in obesity, our study extends recent research in this field …”

“…By investigating EE and NET availability in obesity, our study extends recent research in this field. 7,8 We demonstrated that a higher degree of EE in obese participants is accompanied by a decreased LC NET availability. The LC-NE system is known to be involved in responses to stress.…”

“…In this pilot study, 10 obese participants and 10 non‐obese healthy controls matched for age and sex were included (Table ). The same study cohort of 20 individuals has been investigated previously to describe the role of NE in the severity of depression, as well as in the loss of emotional well‐being with body weight . However, in this study, neuropsychological data was analyzed to determine the relationship of EE and in vivo NET availability.…”

Central noradrenaline transporter availability in highly obese, non-depressed individuals

“…This observational finding should be discussed with other parameters of neural connectivity in the near future to obtain specific group characteristics. Further work on our sample in parallel with these data included associative analyses with resting-state functional MRI data and neuropsychological measures showing initial findings of NAT-based interaction of neuronal and behavioural activity [27]. Within this further data processing we showed that an increased BMI is related to a lowered NAT availability in the hypothalamus together with changes in a network mediating emotional well-being.…”

“…Future studies employing a larger sample size might reveal important individual differences or the influence of gender, stress and genotypes that have been linked to important aspects of eating behaviours and obesity. This is particularly important in light of recent studies on the brain monoaminergic transporter system that also did not show an association between BMI and transporter binding potential across the entire sample [27, 30]. …”