2-Arachidonoylglycerol as a possible treatment for anorexia nervosa in animal model in mice

Sustained insulin treatment restoring metabolic status, body weight, and cognition in an anorexia nervosa-like animal model in mice

INTRODUCTION

Anorexia Nervosa (AN) is a psycho-socio-biological disease characterized by severe weight loss as result of dieting and hyperactivity. Effective treatments are scarce, despite its significant prevalence and mortality. AN patients show lower basal insulin levels and increased metabolic clearance, leading to weight loss, cognitive deficits, and hormonal imbalances. Low-dose polymer insulin could potentially reverse these effects by restoring brain function, reducing fear of weight gain, encouraging food intake, and restoring fat depots. This study evaluates an insulin delivery system designed for sustained release and AN treatment.

METHODS

AN-like model was established through dietary restriction (DR). On days 1-25, mice were on DR, and on days 26-31 they were on ad libitum regimen. An insulin-loaded delivery system was administered subcutaneously (1% w/w insulin). The impact of insulin treatment on gene expression in the hippocampus (cognition, regulation of stress, neurogenesis) and hypothalamus (eating behavior, mood) was assessed. Behavioral assays were conducted to evaluate motor activity and cognitive function.

RESULTS

The delivery system demonstrated sustained insulin release, maintaining therapeutic plasma levels. Diet restriction mice treated with the insulin delivery system showed body weight restoration. Gene expression analysis revealed enhanced expression of CB1 and CB2 genes associated with improved eating behavior and cognition, while POMC expression was reduced. Insulin-polymer treatment restored cognitive function and decreased hyperactivity in the AN-like model.

CONCLUSION

The PSA-RA-based insulin delivery system effectively restores metabolic balance, body weight, and cognitive function in the AN model. Its ability to steadily release insulin makes it a promising candidate for AN treatment."

Novel N-Acylethanolamide Derivatives Affect Body Weight and Energy Balance

Introduction - The obesity pandemic is multifactorial. Nutritional, pharmacologic and surgical interventions are limited in reach and efficacy, raising need for new therapeutics. Aims - Characterization of anorexigenic and cognitive effect and central mechanism of action of novel N-acylethanolamide derivatives. Methods - Sabra mice divided to similar experimental groups, injected IP with: oleyl-L-leucinolamide (1 A), linoleyl-L-leucinolamide (4 A), linoleyl-L-valinolamide (5 A), oleyl-oxycarbonyl-L-valinolamide (1 B), oleyl-oxycarbonyl-D-valinolamide (2 B), oleylamine-carbonyl-L-valinolamide (3 B), oleylamine-carbonyl-D-valinolamide (4 B), and oleyl-L-hydroxyvalineamide (5 B). Control group with vehicle. Body weight and food consumption followed for 39 days. Motor activity and cognitive function by open field test and eight-arm maze. Mice sacrificed and mechanism of action investigated by qPCR. The genes analyzed involved in energy balance and regulation of appetite. Catecholamines and serotonin evaluated. Results - Compounds 1 A, 5 A, 1 B-4 B, caused significant weight loss of 4.2-5.6 % and 5 A, 1 B-4 B, improved cognitive function following 8 i. p. injections of 1 mg/kg during 39 days, by different mechanisms. 5 A, 3 B and 4 B decreased food consumption, whereas 1 A, 5 A and 2 B increased motor activity. 1 A, 4 A, 1 B and 3 B elevated SIRT-1, associated with survival. POMC upregulated by 1 B and 2 B, CART by 1 B, 2 B and 1 A. NPY and CAMKK2 downregulated by 5 A. 4 B enhanced 5-HT levels. 4 A, 5 A, 1 B, 4 B, 5 B decreased FAAH, showing long lasting effect. Conclusions - These new compounds might be developed for the treatment of obesity and for improved cognitive function.

The emerging role of the endocannabinoidome-gut microbiome axis in eating disorders

Among the sources of chemical signals regulating food intake, energy metabolism and body weight, few have attracted recently as much attention as the expanded endocannabinoid system, or endocannabinoidome (eCBome), and the gut microbiome, the two systems on which this review article is focussed. Therefore, it is legitimate to expect that these two systems also play a major role in the etiopathology of eating disorders (EDs), in particular of anorexia nervosa, bulimia nervosa and binge-eating disorder. The major mechanisms through which, also via interactions with other endogenous signaling systems, the eCBome, with its several lipid mediators and receptors, and the gut microbiome, via its variety of microbial kingdoms, phyla and species, and armamentarium of metabolites, intervene in these disorders, are described here, based on several published studies in either experimental models or patients. Additionally, in view of the emerging multi-faceted cross-talk mechanisms between these two complex systems, we discuss the possibility that the eCBome-gut microbiome axis is also involved in EDs.

Insulin normalized brain metabolic status on a Model of Anorexia Nervosa in Mice

INTRODUCTION

Anorexia nervosa is a psycho-socio-biological disease, characterized by self-starvation and distorted perception of body weight. Patients often over-exercise. Insulin is an anabolic hormone that increases food intake and restores body fat and is present in low levels in anorexia nervosa patients: thus may have therapeutic potential in treating anorexia nervosa.

AIMS

to explore whether low levels insulin administration may result in recovery of cerebral function and restoration of metabolic disorder providing a treatment option for anorexia nervosa.

METHODS

Female Sabra mice maintained on DR of 2.0 hours per day for 32 days, in cages with or without wheel attached to an electronic counter (activity wheel). They were then permitted to eat ad libitum for additional 15 days. On the second week, mice were injected ip with 0.5U/kg long acting Insulin(Lantus) or saline and cognitive function was evaluated. Insulin administered three times a week during days 8-32. Mice euthanized on day 48 and cerebral levels of monoamines, 2-AG and expression of genes associated with metabolic status were evaluated.

RESULTS

Activity wheel mice decreased body weight, 2-AG, dopamine levels and 5-HT1A and increased Camkk2 and SIRT1 gene expression compared to mice without it. Insulin increased body weight, decreased revolutions, enhanced NPY and normalized Camkk2, SIRT-1, BDNF, elevated 2-AG and improved cognition in the wheel group.

CONCLUSION

low dose insulin administration to animal model of anorexia associated with exercise, led to alterations and normalization in brain metabolic status and improved cognition. Insulin should be further explored as potential novel treatment for anorexia nervosa.

Effects of endocannabinoids on feed intake, stress response and whole-body energy metabolism in dairy cows

Endocannabinoids, particularly anandamide (AEA) and 2-arachidonoylglycerol (2-AG), are instrumental in regulating energy homeostasis and stress response. However, little is known about the endocannabinoid system (ECS) in ruminants, although EC could improve dairy health and productivity, at least by increasing feed intake. In this study, we report if intraperitoneal (i.p.) AEA and 2-AG administration affects feed intake, whole-body macronutrient metabolism, isolation and restraint stress, and whether diet composition modulates circulating endocannabinoid concentrations in cows. Twenty Simmental cows in late lactation were fed a grass silage and a corn silage based diet. On each diet, cows received daily i.p. injections with either AEA (5 µg/kg; n = 7), 2-AG (2.5 µg/kg; n = 6) or saline (n = 7) for 8 days. Endocannabinoid administration for 5 days under free-ranging (non-stressed) conditions had no effect on feed intake or energy balance, but attenuated the stress-induced suppression of feed intake when housing changed to individual tie-stalls without social or tactile interaction. Endocannabinoids increased whole-body carbohydrate oxidation, reduced fat oxidation, and affected plasma non-esterified fatty acid concentrations and fatty acid contents of total lipids. There was no effect of endocannabinoids on plasma triglyceride concentrations or hepatic lipogenesis. Plasma AEA concentrations were not affected by diet, however, plasma 2-AG concentrations tended to be lower on the corn silage based diet. In conclusion, endocannabinoids attenuate stress-induced hypophagia, increase short-term feed intake and whole-body carbohydrate oxidation and decrease whole-body fat oxidation in cows.

A Role for Peripheral Anandamide and 2-Arachidonoylglycerol in Short-Term Food Intake and Orexigenic Hypothalamic Responses in a Species with Continuous Nutrient Delivery

The endocannabinoid system (ECS) plays a pivotal role in the complex control and regulation of food intake. Pharmacological ECS activation could improve health in energy-deficient stages by increasing food intake, at least in intermittent feeders. However, knowledge of the mechanism regulating appetite in species with continued nutrient delivery is incomplete. The objectives of this pilot study were to investigate the effect of the intraperitoneal (i.p.) administration of the endocannabinoids (ECs) anandamide (AEA) and 2-arachidonoylglycerol (2-AG) on food intake, plasma EC concentrations and hypothalamic orexigenic signaling, and to study how the circulatory EC tone changes in response to short-term food deprivation in dairy cows, a species with continuous nutrient delivery. The administration of EC resulted in higher food intake during the first hour after treatment. Plasma AEA concentrations were significantly increased 2.5 h after AEA injection, whereas plasma 2-AG concentrations remained unchanged 2.5 h after 2-AG injection. The hypothalamic immunoreactivity of cannabinoid receptor 1, agouti-related protein, and orexin-A was not affected by either treatment; however, neuropeptide Y and agouti-related protein mRNA abundances were downregulated in the arcuate nucleus of AEA-treated animals. Short-term food deprivation increased plasma 2-AG, while plasma AEA remained unchanged. In conclusion, i.p.-administered 2-AG and AEA increase food intake in the short term, but only AEA accumulates in the circulation. However, plasma 2-AG concentrations are more responsive to food deprivation than AEA.

Animal Models for Anorexia Nervosa-A Systematic Review

Anorexia nervosa is an eating disorder characterized by intense fear of gaining weight and a distorted body image which usually leads to low caloric intake and hyperactivity. The underlying mechanism and pathogenesis of anorexia nervosa is still poorly understood. In order to learn more about the underlying pathophysiology of anorexia nervosa and to find further possible treatment options, several animal models mimicking anorexia nervosa have been developed. The aim of this review is to systematically search different databases and provide an overview of existing animal models and to discuss the current knowledge gained from animal models of anorexia nervosa. For the systematic data search, the Pubmed—Medline database, Embase database, and Web of Science database were searched. After removal of duplicates and the systematic process of selection, 108 original research papers were included in this systematic review. One hundred and six studies were performed with rodents and 2 on monkeys. Eighteen different animal models for anorexia nervosa were used in these studies. Parameters assessed in many studies were body weight, food intake, physical activity, cessation of the estrous cycle in female animals, behavioral changes, metabolic and hormonal alterations. The most commonly used animal model (75 of the studies) is the activity-based anorexia model in which typically young rodents are exposed to time-reduced access to food (a certain number of hours a day) with unrestricted access to a running wheel. Of the genetic animal models, one that is of particular interest is the anx/anx mice model. Animal models have so far contributed many findings to the understanding of mechanisms of hunger and satiety, physical activity and cognition in an underweight state and other mechanisms relevant for anorexia nervosa in humans.