Altered circulating endocannabinoids in anorexia nervosa during acute and weight‐restored phases: A pilot study

Abstract

Anorexia nervosa (AN) is an eating disorder characterized by a low food intake and often exceeding exercise, leading to a particularly low body × weight proportion. Patients with AN usually report less hunger than healthy controls. Endogenous endocannabinoids (eCBs), specifically the anandamide, have been associated to hunger, as a meal initiator, but research regarding AN and eCB and inconclusive. In this pilot study, we investigated plasma levels of eCB in inpatients with AN during fasting and after eating, both during the acute AN phase and after weight recovery. After an 8-hr fasting period, blood sample was collected from all participants. After that, participants were given a muffin test meal. Blood samples for the investigation of endogenous eCBs anandamide (N-arachidonoylethanolamide [AEA]) and 2-arachidonoylglycerol (2-AG) were then collected after 120 and 240 min. Participants were only allowed to eat and drink what was offered them during the research. AN reported less hunger than controls during fasting and at the end of the experiment. Also, plasma levels of AEA were significantly smaller in AN in comparison with controls in all time points. No significant difference was found for 2-AG plasma levels. After recovery, no significant difference was found for eCB levels. These findings could be interpreted as an AEA deregulation in AN before and after food intake, which persists after weight recovery. These findings may have implications to the pharmacological treatment of AN and to relapse occurring in the disorder.

Association of anandamide and 2-arachidonoylglycerol concentrations with clinical features and body mass index in eating disorders and obesity

“…Although a hypoactive eCB system has been stated in AN [53][54][55], describing a lower CB1R availability [56], findings related to the amount of eCBs remain still inconclusive [52,57]. Monteleone et al [52] described higher plasma AEA concentrations in AN compared with HC, whereas a recent study reported lower AEA concentrations in acute phases of the disorder and post-recovery [57], which was also supported in animal models [56]. Regarding 2-AG, studies in EDs have shown no significant differences in 2-AG concentrations when comparing BSD or AN with HC [45,52,57].…”

Molecular Alterations of the Endocannabinoid System in Psychiatric Disorders

“…Blood samples were collected after an 8-h fasting period, and AEA and 2-AG levels were measured. 2-AG concentrations did not differ [403]. AEA concentrations were significantly lower in AN than in the controls.…”

“…The recent pilot study by Piccolo et al (2020) [403] on patients with AN contradicts the previous studies. Piccolo et al ( 2019) sampled 15 hospitalized AN patients and nine controls.…”

Exploring the Influence of Circulating Endocannabinoids and Nucleus Accumbens Functional Connectivity on Anorexia Nervosa Severity

“…Although there have been still no interventional studies, investigations focused on exploring the eCB system in AN have provided mixed results. While some studies comparing individuals with AN and HC reported elevated AEA concentrations in AN [14,42], other research has identi ed decreased AEA concentrations [13] or no signi cant differences [43]. These alterations in AEA concentrations observed in AN were maintained even after weight restoration [13,14].…”

“…While some studies comparing individuals with AN and HC reported elevated AEA concentrations in AN [14,42], other research has identi ed decreased AEA concentrations [13] or no signi cant differences [43]. These alterations in AEA concentrations observed in AN were maintained even after weight restoration [13,14]. Regarding 2-AG, most studies have found no signi cant differences comparing patients with AN and HC [13,14,42,43].…”