The endocannabinoid system as possible target for the treatment of obesity related disorders: beyond cannabinoid receptors

Worldwide, obesity is one of the most diffused pathologies. Several lines of recent evidence link obesity with a higher risk of neurological pathologies such as anxiety and depression; this consideration stems from the observation that palatable food consumption becomes sometimes necessary to overcome negative mental states, thus sustaining the vicious circle of “food addiction”. Endogenous acylethanolamides (such as anandamide, oleoylethanolamide, palmitoylethanolamide) might play a key role in this scenario since they participate to the mechanisms regulating both reward and mood tone. The present study aims to explore whether the abstinence from a palatable diet, after a long-term ad libitum consumption of it, might produce alterations of the emotional reactivity and mood tone and whether the pharmacological inhibition of fatty acid amide hydrolase (FAAH) by PF-3845 treatment (which causes an increase of acylethanolamide tone) might ameliorate such alterations. We used a rat model of diet-induced obesity based on a cafeteria-style diet. After the first 40 days of extended exposure to cafeteria diet, rats underwent an abstinence period of 28 days. During this period, animals were separated in two different groups: one group was chronically treated with PF-3845 (10 mg/kg, intraperitoneally) and the other group was treated with vehicle (ethanol/tween80/saline 5/5/90). At the end of the treatment rats were subjected to behavioral tests such as the open field test, the elevated plus maze and the forced swimming test and then were sacrificed. Brains were collected to investigate markers of monoaminergic transmission, endocannabinoid tone and inflammation in different brain areas implicated in reward, anxiety and depression. To meet this aim we used different experimental approaches including immunofluorescence, HPLC and western blot analysis. Pearson correlations tests were also conducted to correlate behavioural parameters to monoamine tissue levels in the different brain areas, as well as to investigate monoaminergic and endocannabinoid protein correlations throughout the different brain areas analysed. Our results demonstrate that long term abstinence from a palatable diet might impact both mood and reward processes: in particular, animals subjected to cafeteria diet withdrawal show an anxiety-like behavior and a depressive-like phenotype. Moreover, several neurochemical alterations are also detected in key brain areas involved in the control of mood and reward processes. These include alterations of the expression of proteins partaking to the endocannabinoid system and to the inflammatory-response, alterations in the monoaminergic tone. The repeated administration of the FAAH inhibitor PF-3845 during the abstinence period exerts an anxiolytic and antidepressant effect in abstinent rats and is effective in normalizing protein expression variations and monoamine content alterations in almost all brain areas analyzed. Pearson correlation tests display pattern variations both consequently to diet abstinence and pharmacological treatment. The results obtained from the present study are important in evidencing that palatable food exposure and subsequent abstinence can cause neuroadaptive changes that turn into the development of depression and anxiety, raising the importance of these comorbidities in obesity and palatable food consumption. Most importantly, we observe that enhancing the endogenous tone of acylethanolamides and endocannabinoids by blocking their enzymatic degradation might represent a novel protective strategy for psychiatric comorbidities in obese subjects

Modulation of the oxidative stress and lipid peroxidation by endocannabinoids and their lipid analogues

Growing evidence supports the pivotal role played by oxidative stress in tissue injury development, thus resulting in several pathologies including cardiovascular, renal, neuropsychiatric, and neurodegenerative disorders, all characterized by an altered oxidative status. Reactive oxygen and nitrogen species and lipid peroxidation-derived reactive aldehydes including acrolein, malondialdehyde, and 4-hydroxy-2-nonenal, among others, are the main responsible for cellular and tissue damages occurring in redox-dependent processes. In this scenario, a link between the endocannabinoid system (ECS) and redox homeostasis impairment appears to be crucial. Anandamide and 2-arachidonoylglycerol, the best characterized endocannabinoids, are able to modulate the activity of several antioxidant enzymes through targeting the cannabinoid receptors type 1 and 2 as well as additional receptors such as the transient receptor potential vanilloid 1, the peroxisome proliferator-activated receptor alpha, and the orphan G protein-coupled receptors 18 and 55. Moreover, the endocannabinoids lipid analogues N-acylethanolamines showed to protect cell damage and death from reactive aldehydes-induced oxidative stress by restoring the intracellular oxidants-antioxidants balance. In this review, we will provide a better understanding of the main mechanisms triggered by the cross-talk between the oxidative stress and the ECS, focusing also on the enzymatic and non-enzymatic antioxidants as scavengers of reactive aldehydes and their toxic bioactive adducts

Anxiety associated with palatable food withdrawal is reversed by the selective FAAH inhibitor PF-3845: A regional analysis of the contribution of endocannabinoid signaling machinery

Objective: Consumption of energy-dense palatable "comfort" food can alleviate stress and negative emotions, while abrupt withdrawal from a palatable diet can worsen these symptoms, causing difficulties with adherence to weight-loss diets. Currently, no pharmacological treatment is effective for obesity-related anxiety, so we investigated the endocannabinoid system (ECS), and specifically the fatty acid amide hydrolase (FAAH), as an interesting emerging target in this context because of its key role in the regulation of both energy homeostasis and emotional behavior. Methods: Rats were subjected to exposure and subsequent abstinence from a palatable cafeteria diet. During abstinence period, rats were treated with the selective FAAH inhibitor PF-3845 (10 mg/kg; intraperitoneal administration every other day). Results: Abstinent rats displayed an anxiogenic-like behavior and changes in the proteins of ECS signaling machinery in brain areas involved both in anxiety and food intake regulation. In particular, withdrawal caused a reduction of the expression of cannabinoid receptors in the nucleus accumbens and of enzymes diacylglycerol lipase alpha and monoacylglycerol lipase (MAGL) in the amygdala. Pharmacological inhibition of FAAH exerted an anxiolytic-like effect in abstinent animals and increased both MAGL expression in amygdala and CB2 expression in prefrontal cortex. Discussion: Overall, our results suggest that emotional disturbances associated with dieting are coupled with region-specific alterations in the cerebral expression of the ECS and that the enhancement of the endocannabinoid signaling by FAAH inhibition might represent a novel pharmacological strategy for the treatment of anxiety related to abstinence from palatable food.Funding for open access charge: Universidad de Málaga / CBUA European Regional DevelopmentFunds-European Union, Grant/Award Number:PI19/01577; Instituto de Salud Carlos III,Grant/Award Number: RETICS; Ministerio deCiencia e Innovaci on, Grant/Award Number:ERDF-EU RD16/0017/0001; Ministerodell'Università e della Ricerca, Grant/AwardNumber: 2012JTX3KL; PNRR-RomeTechnopole-FP

Endocrine and Metabolic impact of oral ingestion of a carob-pod derived natural syrup containing D-Pinitol: potential use as a novel sweetener in diabetes

The use of added sugars or non-nutritive sweeteners in processed foods and soft drinks are being blamed for multiple complications associated with obesity and diabetes. High fructose content contributes to obesity and liver steatosis, and excessive consumption of non-nutritive sweeteners can generate gut dysbiosis complicating the metabolic control exerted by the liver. Beyond its evolutionary significance in the selection of foods with a high glucose content as an energy source, the fact is that the consumption of sweets produces a hedonic pleasure in our brain. Then, the challenge stands at: how do we control the use of added sugars while providing a safe, palatable, sweet flavour to foods?. The present work explores an alternative approach, in humans and rodents, for sweetening through the use of a simple carob-pod-derived syrup which contains the inositol D-Pinitol. This inositol is known as an insulin sensitizer in muscle capable of keeping glycaemia while avoiding both unnecessary insulin secretion and the conversion of carbohydrates into fat depots .Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Dietary administration of D-chiro-inositol attenuates sex-specific metabolic imbalances in the 5xFAD mouse model of Alzheimer’s disease

Increasing evidence shows that hypothalamic dysfunction, insulin resistance, and weight loss precede and progress along with the cognitive decline in sporadic Alzheimer’s Disease (AD) with sex differences. This study aimed to determine the effect of oral dietary administration of D-Chiro-inositol (DCI), an inositol used against insulin resistance associated with polycystic ovary, on the occurrence of metabolic disorders in the transgenic 5xFAD mouse model of AD (FAD: Family Alzheimer's Disease). DCI was administered from 6 to 10 months of age to male and female 5xFAD mice and control (non-Tg) littermates. Energy balance and multiple metabolic and inflammatory parameters in the hypothalamus, liver and plasma were evaluated to assess the central and peripheral effects of DCI. Results indicated that weight loss and reduced food intake in 5xFAD mice were associated with decreased neuropeptides controlling food intake and the appearance of a pro-inflammatory state in the hypothalamus. Oral administration of DCI partially restored energy balance and hypothalamic parameters, highlighting an increased expression of Npy and Agrp and female-specific downregulation of Gfap and Igf1. DCI also partially normalized impaired insulin signaling and circulating insulin, GLP-1, and GIP deficiencies in 5xFAD mice. Principal component analysis of metabolic parameters indicated the presence of a female-specific fatty liver in 5xFAD mice: DCI administration reversed hepatic fat accumulation, β-oxidation, inflammation and increased GOT and GPT levels. Our study depicts that metabolic impairment along with the cognitive decline in a mouse model of AD, which is exacerbated in females, can be ameliorated by oral supplementation with insulin-sensitizing DCI.This research was funded by the European Regional Development Funds-European Union (ERDF-EU) and Fatzheimer project EULAC-HEALTH H2020, grant number EU-LACH16/T010131; Ministerio de Economía, Industria y Competitividad, Gobierno de España, grant number RTC-2016-4983-1; EU-ERDF and Instituto de Salud Carlos III (ISCIII), grant numbers PI19/01577 and PI19/00343; Ministerio de Sanidad, Delegación de Gobierno para el Plan Nacional sobre Drogas, grant numbers 2019/040 and 2020/048; Consejería de Transformación Económica, Industria, Conocimiento y Universidades, Junta de Andalucía, grant number P18-TP-5194, INSERM (Institut National de la Santé et de la Recherche Médicale), Nouvelle Aquitaine Region and ANR (grant numbers ANR-18-CE14-0029 MitObesity, Labex BRAIN ANR-10-LABX-43, ANR-10-EQX-008-1 OPTOPATH, ANR-17-CE14-0007 BABrain, ANR-21-CE14-0018-01_StriaPOM to D.C.). A.J.L.-G. (IFI18/00042) holds an “iPFIS” predoctoral contract from the National System of Health, EU-ERDF-ISCIII. B.P.S (IFI21/00024) holds an “iPFIS” predoctoral contract from the National System of Health, EU-ERDF-ISCIII. P.R. (CP19/00068) holds a ‘’Miguel Servet I” research contract from the National System of Health, EU-ERDF-ISCIII. D.M-V. (FI20/00227) holds a “PFIS” pre-doctoral contract from the National System of Health, EU-ERDF-ISCIII. The microscopy for IBA1 and GFAP immunofluorescence was done in the Bordeaux Imaging Center, a service unit of the CNRS-INSERM and Bordeaux University, member of the national infrastructure France BioImaging supported by the LabEX BRAIN and ANR-10-INBS-04. Partial funding for open access charge: Universidad de Málaga

Travel grant SEIC per la partecipazione al 20° congresso SEIC

Travel grant per la partecipazione al ventesimo congresso SEI

Borsa di studio SIF per brevi periodi all'estero

Borsa di studio SIF per brevi periodi all'ester

Borsa di studio SIF per la partecipazione alla CISSN 2018

Travel grant per la partecipazione alla Catania International Summer School of Neuroscienc

Obesity as a Condition Determined by Food Addiction: Should Brain Endocannabinoid System Alterations Be the Cause and Its Modulation the Solution?

Obesity is a complex disorder, and the number of people affected is growing every day. In recent years, research has confirmed the hypothesis that food addiction is a determining factor in obesity. Food addiction is a behavioral disorder characterized by disruptions in the reward system in response to hedonic eating. The endocannabinoid system (ECS) plays an important role in the central and peripheral control of food intake and reward-related behaviors. Moreover, both obesity and food addiction have been linked to impairments in the ECS function in various brain regions integrating peripheral metabolic signals and modulating appetite. For these reasons, targeting the ECS could be a valid pharmacological therapy for these pathologies. However, targeting the cannabinoid receptors with inverse agonists failed when used in clinical contexts as a consequence of the induction of affective disorders. In this context, new classes of drugs acting either on CB1 and/or CB2 receptors or on synthetic and degradation enzymes of endogenous cannabinoids are being studied. However, further investigation is necessary to find safe and effective treatments that can exert anti-obesity effects, normalizing reward-related behaviors without causing important adverse mood effects.This work was supported by grants from the following institutions: RETICS Networks Subpro-gram (Addictive Disorders Network, RD16/0017/0001) funded by Instituto de Salud Carlos III (ISCIII); Proyectos de Desarrollo tecnológico (Grant DTS19/00125) funded by Ministerio de Ciencia, Innovación y Universidades and the European Regional Development Fund/European Social Fund (FEDER/ESF); Health Research Project (grant PI19/01577) funded by, Ministerio de Ciencia, Innovación y Universidades, ISCIII and FEDER/ESF; Plan Nacional Sobre Drogas (Grant PND2018/044) funded by the Government Delegation for the National Plan on Drugs, Ministerio de Salud, Servicios Sociales e Igualdad and FEDER/FSE; Health Research Project (Grant PI-0139-2018) Consejería de Salud y Familias de la Junta De Andalucía.Ye