Preclinical and Clinical Evidence for a Distinct Regulation of Mu Opioid and Type 1 Cannabinoid Receptor Genes Expression in Obesity

Fatty Acid Amide Hydrolase and Cannabinoid Receptor Type 1 Genes Regulation is Modulated by Social Isolation in Rats

Social isolation is a state of lack of social connections, involving the modulation of different molecular signalling cascades and associated with high risk of mental health issues. To investigate if and how gene expression is modulated by social experience at the central level, we analyzed the effects of 5 weeks of social isolation in rats focusing on endocannabinoid system genes transcription in key brain regions involved in emotional control. We observed selective reduction in mRNA levels for fatty acid amide hydrolase (Faah) and cannabinoid receptor type 1 (Cnr1) genes in the amygdala complex and of Cnr1 in the prefrontal cortex of socially isolated rats when compared to controls, and these changes appear to be partially driven by trimethylation of Lysine 27 and acetylation of Lysine 9 at Histone 3. The alterations of Cnr1 transcriptional regulation result also directly correlated with those of oxytocin receptor gene. We here suggest that to counteract the effects of SI, it is of relevance to restore the endocannabinoid system homeostasis via the use of environmental triggers able to revert those epigenetic mechanisms accounting for the alterations observed.

The Impact of Opioid Receptor Gene Polymorphism on Fentanyl and Alfentanil's Analgesic Effects in the Pediatric Perioperative Period

Introduction

The polymorphism of the gene coding mu-opioid receptor (OPRM1) is one of the factors contributing to the variability in the response to opioid analgesics in children. The goal of this study is to investigate its role in association with postoperative acute pain in children of various ages.

Methods

This prospective study analyzed 110 pediatric patients, after plastic or orthopedic surgery, who were genotyped and randomly assigned to receive fentanyl or alfentanil. Postoperative pain was rated using Numerical Rating Scale (0-10). All the patients were genotyped forOPRM1 118A>G (rs1799971) gene polymorphism.

Results

School children under the age of 11 with the OPRM1 AA genotype were shown to have a higher BMI (p<0.05). Children over the age of 12 carrying G allele OPRM1, had increased postoperative pain sensitivity and intensity (3.28±1.95 vs 4.91±2.17; p<0.05), as compared to AA allele carriers.

Discussion

OPRM1 118A>G polymorphism may explain the variation in the perception of postoperative pain in children over the age of 12 and may be a useful predictor for adjusting the dose of analgesics, but the dose is relative to the patient's needs regardless of his genetic characteristics. In younger children, carriers of polymorphic OPRM1 118G allele may be protected from obesity, due to diminished MOP expression.

Obesity-mediated Lipoinflammation Modulates Food Reward Responses

Accumulation of white adipose tissue (WAT) during obesity is associated with the development of chronic low-grade inflammation, a biological process known as lipoinflammation. Systemic and central lipoinflammation accumulates pro-inflammatory cytokines including IL-6, IL-1β and TNF-α in plasma and also in brain, disrupting neurometabolism and cognitive behavior. Obesity-mediated lipoinflammation has been reported in brain regions of the mesocorticolimbic reward circuit leading to alterations in the perception and consumption of ultra-processed foods. While still under investigation, lipoinflammation targets two major outcomes of the mesocorticolimbic circuit during food reward: perception and motivation ("Wanting") and the pleasurable feeling of feeding ("Liking"). This review will provide experimental and clinical evidence supporting the contribution of obesity- or overnutrition-related lipoinflammation affecting the mesocorticolimbic reward circuit and enhancing food reward responses. We will also address neuroanatomical targets of inflammatory profiles that modulate food reward responses during obesity and describe potential cellular and molecular mechanisms of overnutrition linked to addiction-like behavior favored by brain lipoinflammation.

A possible role for G-quadruplexes formation and DNA methylation at IMOOD gene promoter in Obsessive Compulsive Disorder

Obsessive Compulsive Disorder (OCD) is a mental health condition still classified and diagnosed with subjective interview-based assessments and which molecular clues have not completely been elucidated. We have recently identified a new regulator of anxiety and OCD-like behavior called Immuno-moodulin (IMOOD) and, here, we report that IMOOD gene promoter is differentially methylated in OCD subjects when compared to genomic material collected from healthy controls and this alteration is significantly correlated with the increased expression of the gene in OCD. We also demonstrated that IMOOD promoter can form G-quadruplexes and we suggest that, in homeostatic conditions, these structures could evoke DNA-methylation silencing the gene, whereas in pathological conditions, like OCD, could induce gene expression making the promoter more accessible to transcriptional factors. We here thus further suggest IMOOD as a new biomarker for OCD and also hypothesize new mechanisms of gene regulation.

Endocannabinoid signaling and epigenetics modifications in the neurobiology of stress-related disorders

Stress exposure is associated with psychiatric conditions, such as depression, anxiety, and post-traumatic stress disorder (PTSD). It is also a vulnerability factor to developing or reinstating substance use disorder. Stress causes several changes in the neuro-immune-endocrine axis, potentially resulting in prolonged dysfunction and diseases. Changes in several transmitters, including serotonin, dopamine, glutamate, gamma-aminobutyric acid (GABA), glucocorticoids, and cytokines, are associated with psychiatric disorders or behavioral alterations in preclinical studies. Complex and interacting mechanisms make it very difficult to understand the physiopathology of psychiatry conditions; therefore, studying regulatory mechanisms that impact these alterations is a good approach. In the last decades, the impact of stress on biology through epigenetic markers, which directly impact gene expression, is under intense investigation; these mechanisms are associated with behavioral alterations in animal models after stress or drug exposure, for example. The endocannabinoid (eCB) system modulates stress response, reward circuits, and other physiological functions, including hypothalamus-pituitary-adrenal axis activation and immune response. eCBs, for example, act retrogradely at presynaptic neurons, limiting the release of neurotransmitters, a mechanism implicated in the antidepressant and anxiolytic effects after stress. Epigenetic mechanisms can impact the expression of eCB system molecules, which in turn can regulate epigenetic mechanisms. This review will present evidence of how the eCB system and epigenetic mechanisms interact and the consequences of this interaction in modulating behavioral changes after stress exposure in preclinical studies or psychiatric conditions. Moreover, evidence that correlates the involvement of the eCB system and epigenetic mechanisms in drug abuse contexts will be discussed.

What Happens In Utero Does Not Stay In Utero: a Review of Evidence for Prenatal Epigenetic Programming by Per- and Polyfluoroalkyl Substances (PFAS) in Infants, Children, and Adolescents

PURPOSE OF REVIEW

Review human literature on the relationship between prenatal exposure to per- and polyfluoroalkyl substances (PFAS) and epigenetic modifications in infants, children, and adolescents < 18 years of age.

RECENT FINDINGS

Eleven studies were identified, with study populations located in the U.S., Taiwan, Japan, and the Kingdom of Denmark. Many studies (n = 5) were cross-sectional, with PFAS exposure and epigenetic outcomes measured in the same tissue collected at delivery via cord blood or dried newborn blood spots. The other six studies were prospective, with prenatal PFAS measured on maternal blood during pregnancy and DNA methylation (DNAm) assessed in cord blood and childhood peripheral leukocytes (n = 1 study). Epigenetic marks of interest included global DNAm measures (LINE-1, Alu, and an ELISA-based method), candidate genes (IFG2, H19, and MEST), and epigenome-wide DNA methylation via array-based methods (Infinium 450 K and EPIC). Two studies using array-based methods employed discovery and validation paradigms, in which a small subset of loci (n = 6 and n = 4) were replicated in the discovery population. One site (TNXB) was a hit in two independent studies. Collectively, loci associated with PFAS were in regions involved in growth and development, lipid metabolism, and nutrient metabolism. There is moderate human evidence supporting associations of prenatal PFAS exposure on DNAm at birth, with one study suggesting sustained effects into childhood. Future studies are warranted to link PFAS-associated DNAm to health outcomes, as well as to investigate the role of other epigenetic marks such as hydroxymethylation, miRNA expression, and histone modifications.

Does a High Postoperative Opioid Dose Predict Chronic Use After ACDF?

OBJECTIVE

The purpose of this study is to determine if increased postoperative prescription opioid dosing is an isolated predictor of chronic opioid use after anterior cervical diskectomy and fusion (ACDF).

METHODS

A retrospective cohort analysis of patients undergoing ACDF for degenerative diseases from 2016-2019 at a single institution was performed. Preoperative and postoperative opioid and benzodiazepine prescriptions, including morphine milligram equivalents (MMEs) and duration of use, were obtained from the Pennsylvania Prescription Drug Monitoring Program. Univariate analysis compared patient demographics and surgical factors across groups on the basis of postoperative opioid dose (high: MME ≥90, low: MME <90) and chronicity of use (chronic: ≥120 days or >10 prescriptions). Logistic regressions identified predictors of high opioid dose and chronic use.

RESULTS

A total of 385 patients were included. Preoperative opioid tolerance and tobacco use were associated with high postoperative opioid dose and chronic usage. Younger age correlated with high-dose prescriptions. Increased body mass index and preoperative benzodiazepine use were associated with chronic opioid use. Chronic postoperative opioid use correlated with high-dose prescriptions, change in opioid prescribed, private pay scripts, and more than 1 prescriber and pharmacy. Logistic regression identified high postoperative opioid dose, opioid tolerance, increased body mass index, and no prior cervical surgery as predictors of chronic opioid use. Regression analysis determined younger age, increased medical comorbidities, and opioid tolerance to be predictors for high MME prescriptions.

CONCLUSIONS

High postoperative opioid dose independently predicted chronic opioid use after ACDF regardless of preoperative opioid tolerance.

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.

PUBLIC SIGNIFICANCE

The present study focused on evaluating the role of the endocannabinoid system in modulating withdrawal from naturally rewarding activities that have an impact on mood, such as feeding. The variations observed in the emotional behavior of abstinent rats was linked to neuroadaptations of the ECS in specific brain areas.

DNA Methylation Analysis of Cnr1 Gene Promoter

DNA methylation pattern could be considered a biomarker to be exploited for the study and management of several human diseases. In this chapter, detailed protocols are provided for two experimental approaches used for quantitative methylation analysis of bisulfite converted DNA: methylation-specific PCR (MSP) and pyrosequencing.

Bioinformatics of the Endocannabinoid System: Study of DNA Methylation at Rat Cnr1 Gene Promoter

In this chapter, we will describe the bioinformatic tools that allow verifying the presence of CpG islands in a gene promoter region. We will also describe the tools needed to identify consensus motifs for specific transcription factors, focusing on the study of rat type-1 cannabinoid receptor gene (R_Cnr1) as a case study.

Endocannabinoid System Regulation in Female Rats with Recurrent Episodes of Binge Eating

Recurrent Binge Eating (BE) episodes characterize several eating disorders. Here, we attempted to reassemble a condition closer to BE disorder, and we analyzed whether recurrent episodes might evoke molecular alterations in the hypothalamus of rats. The hypothalamus is a brain region which is sensitive to stress and relevant in motivated behaviors, such as food intake. A well-characterized animal model of BE, in which a history of intermittent food restriction and stress induce binge-like palatable food consumption, was used to analyze the transcriptional regulation of the endocannabinoid system (ECS). We detected, in rats showing the BE behavior, an up-regulated gene expression of cannabinoid type-1 receptor (CB1), sn-1-specific diacylglycerol lipase, as well as fatty acid amide hydrolase (Faah) and monoacylglycerol lipase. A selective reduction in DNA methylation was also observed at the promoter of Faah, which is consistent with the changes in the gene expression. Moreover, BE behavior in rats was associated with an increase in anandamide (AEA) levels. Our findings support the relevant role of the ECS in the regulation of food intake in rats subjected to repeated BE episodes, and, in particular, on AEA signaling, acting via CB1 and FAAH modulation. Notably, the epigenetic regulation of the Faah gene might suggest this enzyme as a possible target for developing new therapeutical approaches.

Molecular Insights into Epigenetics and Cannabinoid Receptors

The actions of cannabis are mediated by G protein-coupled receptors that are part of an endogenous cannabinoid system (ECS). ECS consists of the naturally occurring ligands N-arachidonylethanolamine (anandamide) and 2-arachidonoylglycerol (2-AG), their biosynthetic and degradative enzymes, and the CB1 and CB2 cannabinoid receptors. Epigenetics are heritable changes that affect gene expression without changing the DNA sequence, transducing external stimuli in stable alterations of the DNA or chromatin structure. Cannabinoid receptors are crucial candidates for exploring their functions through epigenetic approaches due to their significant roles in health and diseases. Epigenetic changes usually promote alterations in the expression of genes and proteins that can be evaluated by various transcriptomic and proteomic analyses. Despite the exponential growth of new evidence on the critical functions of cannabinoid receptors, much is still unknown regarding the contribution of various genetic and epigenetic factors that regulate cannabinoid receptor gene expression. Recent studies have identified several immediate and long-lasting epigenetic changes, such as DNA methylation, DNA-associated histone proteins, and RNA regulatory networks, in cannabinoid receptor function. Thus, they can offer solutions to many cellular, molecular, and behavioral impairments found after modulation of cannabinoid receptor activities. In this review, we discuss the significant research advances in different epigenetic factors contributing to the regulation of cannabinoid receptors and their functions under both physiological and pathological conditions. Increasing our understanding of the epigenetics of cannabinoid receptors will significantly advance our knowledge and could lead to the identification of novel therapeutic targets and innovative treatment strategies for diseases associated with altered cannabinoid receptor functions.

Regulation of oxytocin receptor gene expression in obsessive-compulsive disorder: a possible role for the microbiota-host epigenetic axis

BACKGROUND

Obsessive-compulsive disorder (OCD) is a prevalent and severe clinical condition. Robust evidence suggests a gene-environment interplay in its etiopathogenesis, yet the underlying molecular clues remain only partially understood. In order to further deepen our understanding of OCD, it is essential to ascertain how genes interact with environmental risk factors, a cross-talk that is thought to be mediated by epigenetic mechanisms. The human microbiota may be a key player, because bacterial metabolites can act as epigenetic modulators. We analyzed, in the blood and saliva of OCD subjects and healthy controls, the transcriptional regulation of the oxytocin receptor gene and, in saliva, also the different levels of major phyla. We also investigated the same molecular mechanisms in specific brain regions of socially isolated rats showing stereotyped behaviors reminiscent of OCD as well as short chain fatty acid levels in the feces of rats.

RESULTS

Higher levels of oxytocin receptor gene DNA methylation, inversely correlated with gene expression, were observed in the blood as well as saliva of OCD subjects when compared to controls. Moreover, Actinobacteria also resulted higher in OCD and directly correlated with oxytocin receptor gene epigenetic alterations. The same pattern of changes was present in the prefrontal cortex of socially-isolated rats, where also altered levels of fecal butyrate were observed at the beginning of the isolation procedure.

CONCLUSIONS

This is the first demonstration of an interplay between microbiota modulation and epigenetic regulation of gene expression in OCD, opening new avenues for the understanding of disease trajectories and for the development of new therapeutic strategies.

Hippocampal Cannabinoid 1 Receptors Are Modulated Following Cocaine Self-administration in Male Rats

Cocaine addiction is a complex pathology inducing long-term neuroplastic changes that, in turn, contribute to maladaptive behaviors. This behavioral dysregulation is associated with transcriptional reprogramming in brain reward circuitry, although the mechanisms underlying this modulation remain poorly understood. The endogenous cannabinoid system may play a role in this process in that cannabinoid mechanisms modulate drug reward and contribute to cocaine-induced neural adaptations. In this study, we investigated whether cocaine self-administration induces long-term adaptations, including transcriptional modifications and associated epigenetic processes. We first examined endocannabinoid gene expression in reward-related brain regions of the rat following self-administered (0.33 mg/kg intravenous, FR1, 10 days) cocaine injections. Interestingly, we found increased Cnr1 expression in several structures, including prefrontal cortex, nucleus accumbens, dorsal striatum, hippocampus, habenula, amygdala, lateral hypothalamus, ventral tegmental area, and rostromedial tegmental nucleus, with most pronounced effects in the hippocampus. Endocannabinoid levels, measured by mass spectrometry, were also altered in this structure. Chromatin immunoprecipitation followed by qPCR in the hippocampus revealed that two activating histone marks, H3K4Me3 and H3K27Ac, were enriched at specific endocannabinoid genes following cocaine intake. Targeting CB1 receptors using chromosome conformation capture, we highlighted spatial chromatin re-organization in the hippocampus, as well as in the nucleus accumbens, suggesting that destabilization of the chromatin may contribute to neuronal responses to cocaine. Overall, our results highlight a key role for the hippocampus in cocaine-induced plasticity and broaden the understanding of neuronal alterations associated with endocannabinoid signaling. The latter suggests that epigenetic modifications contribute to maladaptive behaviors associated with chronic drug use.

Supplementation with Lactiplantibacillus plantarum IMC 510 Modifies Microbiota Composition and Prevents Body Weight Gain Induced by Cafeteria Diet in Rats

Changes in functionality and composition of gut microbiota (GM) have been associated and may contribute to the development and maintenance of obesity and related diseases. The aim of our study was to investigate for the first time the impact of Lactiplantibacillus (L.) plantarum IMC 510 in a rat model of diet-induced obesity, specifically in the cafeteria (CAF) diet. This diet provides a strong motivation to voluntary overeat, due to the palatability and variety of selected energy-dense foods. The oral administration for 84 days of this probiotic strain, added to the CAF diet, decreased food intake and body weight gain. Accordingly, it ameliorated body mass index, liver and white adipose tissue weight, hepatic lipid accumulation, adipocyte size, serum parameters, including glycemia and low-density lipoprotein levels, in CAF fed rats, potentially through leptin control. In this scenario, L. plantarum IMC 510 showed also beneficial effects on GM, limiting the microbial imbalance established by long exposure to CAF diet and preserving the proportion of different bacterial taxa. Further research is necessary to better elucidate the relationship between GM and overweight and then the mechanism of action by which L. plantarum IMC 510 modifies weight. However, these promising results prompt a clear advantage of probiotic supplementation and identify a new potential probiotic as a novel and safe therapeutic approach in obesity prevention and management.

Factors Predictive of Prolonged Postoperative Narcotic Usage Following Orthopaedic Surgery

BACKGROUND

The purpose of this comprehensive review was to investigate risk factors associated with prolonged opioid use after orthopaedic procedures. A comprehensive review of the opioid literature may help to better guide preoperative management of expectations as well as opioid-prescribing practices.

METHODS

A systematic review of all studies pertaining to opioid use in relation to orthopaedic procedures was conducted using the MEDLINE, Embase, and CINAHL databases. Data from studies reporting on postoperative opioid use at various time points were collected. Opioid use and risk of prolonged opioid use were subcategorized by subspecialty, and aggregate data for each category were calculated.

RESULTS

There were a total of 1,445 eligible studies, of which 45 met inclusion criteria. Subspecialties included joint arthroplasty, spine, trauma, sports, and hand surgery. A total of 458,993 patients were included, including 353,330 (77%) prolonged postoperative opioid users and 105,663 (23%) non-opioid users. Factors associated with prolonged postoperative opioid use among all evaluated studies included body mass index (BMI) of ≥40 kg/m (relative risk [RR], 1.06 to 2.32), prior substance abuse (RR, 1.08 to 3.59), prior use of other medications (RR, 1.01 to 1.46), psychiatric comorbidities (RR, 1.08 to 1.54), and chronic pain conditions including chronic back pain (RR, 1.01 to 10.90), fibromyalgia (RR, 1.01 to 2.30), and migraines (RR, 1.01 to 5.11). Age cohorts associated with a decreased risk of prolonged postoperative opioid use were those ≥31 years of age for hand procedures (RR, 0.47 to 0.94), ≥50 years of age for total hip arthroplasty (RR, 0.70 to 0.80), and ≥70 years of age for total knee arthroplasty (RR, 0.40 to 0.80). Age cohorts associated with an increased risk of prolonged postoperative opioid use were those ≥50 years of age for sports procedures (RR, 1.11 to 2.57) or total shoulder arthroplasty (RR, 1.26 to 1.40) and those ≥70 years of age for spine procedures (RR, 1.61). Identified risk factors for postoperative use were similar across subspecialties.

CONCLUSIONS

We provide a comprehensive review of the various preoperative and postoperative risk factors associated with prolonged opioid use after elective and nonelective orthopaedic procedures. Increased BMI, prior substance abuse, psychiatric comorbidities, and chronic pain conditions were most commonly associated with prolonged postoperative opioid use. Careful consideration of elective surgical intervention for painful conditions and perioperative identification of risk factors within each patient's biopsychosocial context will be essential for future modulation of physician opioid-prescribing patterns.

LEVEL OF EVIDENCE

Prognostic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Endogenous opiates and behavior: 2019

This paper is the forty-second consecutive installment of the annual anthological review of research concerning the endogenous opioid system, summarizing articles published during 2019 that studied the behavioral effects of molecular, pharmacological and genetic manipulation of opioid peptides and receptors as well as effects of opioid/opiate agonists and antagonists. The review is subdivided into the following specific topics: molecular-biochemical effects and neurochemical localization studies of endogenous opioids and their receptors (1), the roles of these opioid peptides and receptors in pain and analgesia in animals (2) and humans (3), opioid-sensitive and opioid-insensitive effects of nonopioid analgesics (4), opioid peptide and receptor involvement in tolerance and dependence (5), stress and social status (6), learning and memory (7), eating and drinking (8), drug abuse and alcohol (9), sexual activity and hormones, pregnancy, development and endocrinology (10), mental illness and mood (11), seizures and neurologic disorders (12), electrical-related activity and neurophysiology (13), general activity and locomotion (14), gastrointestinal, renal and hepatic functions (15), cardiovascular responses (16), respiration and thermoregulation (17), and immunological responses (18).

What Role Does the Endocannabinoid System Play in the Pathogenesis of Obesity?

The endocannabinoid system (ECS) is an endogenous signaling system formed by specific receptors (cannabinoid type 1 and type 2 (CB₁ and CB₂)), their endogenous ligands (endocannabinoids), and enzymes involved in their synthesis and degradation. The ECS, centrally and peripherally, is involved in various physiological processes, including regulation of energy balance, promotion of metabolic process, food intake, weight gain, promotion of fat accumulation in adipocytes, and regulation of body homeostasis; thus, its overactivity may be related to obesity. In this review, we try to explain the role of the ECS and the impact of genetic factors on endocannabinoid system modulation in the pathogenesis of obesity, which is a global and civilizational problem affecting the entire world population regardless of age. We also emphasize that the search for potential new targets for health assessment, treatment, and the development of possible therapies in obesity is of great importance.

Tart cherry (Prunus cerasus L.) dietary supplement modulates visceral adipose tissue CB1 mRNA levels along with other adipogenesis-related genes in rat models of diet-induced obesity

PURPOSE

There is increasing evidence for the involvement of dietary bioactive compounds in the cross-talk modulation of endocannabinoid system and some of the key regulators of transcriptional control for adipogenesis.

METHODS

We aimed to characterize the expression of cannabinoid CB1/CB2 receptors and fatty acid amide hydrolase (FAAH) along with selected adipogenesis-related genes (PPARγ, SREBP-1c and PREF-1), adipocyte-secreted factors (leptin and adiponectin), mitochondrial bioenergetic modulators (PGC-1A and UCP-2), and transient receptor potential vanilloid subtype 1 (TRPV1) and 2 (TRPV2) channels in visceral adipose tissue of rats fed with a high-fat diet (HFD) containing either tart cherry seeds alone or tart cherry seeds and juice for 17 weeks. The visceral adipose tissue was weighed and checked the expression of different markers by qRT-PCR, Western blot and immunohistochemistry.

RESULTS

Tart cherry supplements were able to downregulate the HFD-induced mRNA expression of CB1 receptor, SREBP-1c, PPARγ, leptin, TRPV1 and TRPV2 resulting in potential anti-adipogenic effects.

CONCLUSION

The present study points out that the intake of bioactive constituents of tart cherry may attenuate the effect of adipogenesis by acting directly on the adipose tissue and modulating the interplay between CB1, PPARγ and TRPV channel gene transcription.

On the Role of Central Type-1 Cannabinoid Receptor Gene Regulation in Food Intake and Eating Behaviors

Different neuromodulatory systems are involved in long-term energy balance and body weight and, among these, evidence shows that the endocannabinoid system, in particular the activation of type-1 cannabinoid receptor, plays a key role. We here review current literature focusing on the role of the gene encoding type-1 cannabinoid receptors in the CNS and on the modulation of its expression by food intake and specific eating behaviors. We point out the importance to further investigate how environmental cues might have a role in the development of obesity as well as eating disorders through the transcriptional regulation of this gene in order to prevent or to treat these pathologies.

Food Addiction and Psychosocial Adversity: Biological Embedding, Contextual Factors, and Public Health Implications

The role of stress, trauma, and adversity particularly early in life has been identified as a contributing factor in both drug and food addictions. While links between traumatic stress and substance use disorders are well documented, the pathways to food addiction and obesity are less established. This review focuses on psychosocial and neurobiological factors that may increase risk for addiction-like behaviors and ultimately increase BMI over the lifespan. Early childhood and adolescent adversity can induce long-lasting alterations in the glucocorticoid and dopamine systems that lead to increased addiction vulnerability later in life. Allostatic load, the hypothalamic-pituitary-adrenal axis, and emerging data on epigenetics in the context of biological embedding are highlighted. A conceptual model for food addiction is proposed, which integrates data on the biological embedding of adversity as well as upstream psychological, social, and environmental factors. Dietary restraint as a feature of disordered eating is discussed as an important contextual factor related to food addiction. Discussion of various public health and policy considerations are based on the concept that improved knowledge of biopsychosocial mechanisms contributing to food addiction may decrease stigma associated with obesity and disordered eating behavior.

Underlying Susceptibility to Eating Disorders and Drug Abuse: Genetic and Pharmacological Aspects of Dopamine D4 Receptors

The dopamine D4 receptor (DRD4) has a predominant expression in the prefrontal cortex (PFC), brain area strictly involved in the modulation of reward processes related to both food and drug consumption. Additionally, the human DRD4 gene is characterized by a variable number of tandem repeats (VNTR) in the exon 3 and, among the polymorphic variants, the 7-repeat (7R) allele appears as a contributing factor in the neurobiological mechanisms underlying drug abuse, aberrant eating behaviors and related comorbidities. The 7R variant encodes for a receptor with a blunted intracellular response to dopamine, and carriers of this polymorphism might be more tempted to enhance dopamine levels in the brain, through the overconsumption of drugs of abuse or palatable food, considering their reinforcing properties. Moreover, the presence of this polymorphism seems to increase the susceptibility of individuals to engage maladaptive eating patterns in response to negative environmental stimuli. This review is focused on the role of DRD4 and DRD4 genetic polymorphism in these neuropsychiatric disorders in both clinical and preclinical studies. However, further research is needed to better clarify the complex DRD4 role, by using validated preclinical models and novel compounds more selective for DRD4.

Percepción subjetiva de manejo emocional, ansiedad y patrones de ingesta relacionados con aislamiento por COVID-19

El periodo de aislamiento social se considera un detonante de ansiedad, y genera alteraciones en la forma de alimentarse. El objetivo de esta investigación fue determinar la relación entre la percepción subjetiva del manejo de las emociones y la ansiedad con los patrones disfuncionales de la ingesta en el periodo de aislamiento social por COVID-19, en participantes colombianos. La investigación es exploratoria de tipo transversal analítico. Un total de 450 colombianos mayores de 18 años (sexo: 82 % femenino y 18 % masculino) respondieron un cuestionario virtual sobre la percepción subjetiva del manejo de las emociones y la ansiedad; también, se aplicó el cuestionario de tres factores de alimentación para identificar patrones disfuncionales de la ingesta. Se reportó un riesgo 3 veces mayor de presentar ansiedad en las personas que manifestaron un manejo inadecuado de sus emociones. Asimismo, aquellos cuya percepción fue un inadecuado manejo de emociones y ansiedad presentaron mayor nivel de patrones disfuncionales de ingesta como la desinhibición (p < 0.0001) e ingesta emocional (p < 0.0001). Se concluyó que la percepción subjetiva del manejo inadecuado de las emociones y de ansiedad, incrementan la ingesta emocional y la desinhibición, en colombianos en aislamiento social.

Brief daily access to cafeteria-style diet impairs hepatic metabolism even in the absence of excessive body weight gain in rats

Numerous nutritional approaches aimed at reducing body weight have been developed as a strategy to reduce obesity. Most of these interventions rely on reducing caloric intake or limiting calories access to a few hours per day. In this work, we analyzed the effects of the extended (24 hours/day) or restricted (1 hour/day) access to a cafeteria-style (CAF) diet, on rat body weight and hepatic lipid metabolism, with respect to control rats (CTR) fed with a standard chow diet. The body weight gain of restricted-fed rats was not different from CTR, despite the slightly higher total caloric intake, but resulted significantly lower than extended-fed rats, which showed a CAF diet-induced obesity and a dramatically higher total caloric intake. However, both CAF-fed groups of rats showed, compared to CTR, unhealthy serum and hepatic parameters such as higher serum glucose level, lower HDL values, and increased hepatic triacylglycerol and cholesterol amount. The hepatic expression and activity of key enzymes of fatty acid synthesis, acetyl-CoA carboxylase (ACC), and fatty acid synthase (FAS), was similarly reduced in both CAF-fed groups of rats with respect to CTR. Anyway, while in extended-fed rats this reduction was associated to a long-term mechanism involving sterol regulatory element-binding protein-1 (SREBP-1), in restricted-fed animals a short-term mechanism based on PKA and AMPK activation occurred in the liver. Furthermore, hepatic fatty acid oxidation (FAO) and oxidative stress resulted significantly increased in extended, but not in restricted-fed rats, as compared to CTR. Overall, these results demonstrate that although limiting the total caloric intake might successfully fight obesity development, the nutritional content of the diet is the major determinant for the health status.

Effects of Prunus cerasus L. Seeds and Juice on Liver Steatosis in an Animal Model of Diet-Induced Obesity

The accumulation of adipose tissue increases the risk of several diseases. The fruits-intake, containing phytochemicals, is inversely correlated with their development. This study evaluated the effects of anthocyanin-rich tart cherries in diet-induced obese (DIO) rats. DIO rats were exposed to a high-fat diet with the supplementation of tart cherry seeds powder (DS) and seed powder plus juice (DJS). After 17 weeks, the DIO rats showed an increase of body weight, glycaemia, insulin, and systolic blood pressure. In the DS and DJS groups, there was a decrease of systolic blood pressure, glycaemia, triglycerides, and thiobarbituric reactive substances in the serum. In the DJS rats, computed tomography revealed a decrease in the spleen-to-liver attenuation ratio. Indeed, sections of the DIO rats presented hepatic injury characterized by steatosis, which was lower in the supplemented groups. In the liver of the DIO compared with rats fed with a standard diet (CHOW), a down-regulation of the GRP94 protein expression and a reduction of LC3- II/LC3-I ratio were found, indicating endoplasmic reticulum stress and impaired autophagy flux. Interestingly, tart cherry supplementation enhanced both unfolded protein response (UPR) and autophagy. This study suggests that tart cherry supplementation, although it did not reduce body weight in the DIO rats, prevented its related risk factors and liver steatosis.

Epigenetic regulation of the cannabinoid receptor CB1 in an activity-based rat model of anorexia nervosa

OBJECTIVE

Both environmental and genetic factors are known to contribute to the development of anorexia nervosa (AN), but the exact etiology remains poorly understood. Herein, we studied the transcriptional regulation of the endocannabinoid system, an interesting target for body weight maintenance and the control of food intake and energy balance.

METHOD

We used two well-characterized animal models of AN: (a) the activity-based anorexia (ABA) model in which rats, housed with running wheels and subjected to daily food restriction, show reductions in body weight and increase in physical activity; (b) the genetic anx/anx mouse displaying the core features of AN: low food intake and emaciation.

RESULTS

Among the evaluated endocannabinoid system components, we observed a selective and significant down-regulation of the gene encoding for the type 1 cannabinoid receptor (Cnr1) in ABA rats' hypothalamus and nucleus accumbens and, in the latter area, a consistent, significant and correlated increase in DNA methylation at the gene promoter. No changes were evident in the anx/anx mice except for a down-regulation of Cnr1, in the prefrontal cortex.

DISCUSSION

Our findings support a possible role for Cnr1 in the ABA animal model of AN. In particular, its regulation in the nucleus accumbens appears to be triggered by environmental cues due to the consistent epigenetic modulation of the promoter. These data warrant further studies on Cnr1 regulation as a possible target for treatment of AN.

Modulation of Pain Sensitivity by Chronic Consumption of Highly Palatable Food Followed by Abstinence: Emerging Role of Fatty Acid Amide Hydrolase

There is a strong relationship between palatable diet and pain sensitivity, and the cannabinoid and opioid systems might play an important role in this correlation. The palatable diet used in many animal models of obesity is the cafeteria (CAF) diet, based on human food with high sugar, salt, and fat content. In this study, we investigated whether long-term exposure to a CAF diet could modify pain sensitivity and explored the role of the cannabinergic system in this modification. Male Sprague–Dawley rats were divided into two groups: one fed with standard chow only (CO) and the other with extended access (EA) to a CAF diet. Hot plate and tail flick tests were used to evaluate pain sensitivity. At the end of a 40-day CAF exposure, EA rats showed a significant increase in the pain threshold compared to CO rats, finding probably due to up-regulation of CB1 and mu-opioid receptors. Instead, during abstinence from palatable foods, EA animals showed a significant increase in pain sensibility, which was ameliorated by repeated treatment with a fatty acid amide hydrolase inhibitor, PF-3845 (10 mg/kg, intraperitoneally), every other day for 28 days. Ex vivo analysis of the brains of these rats clearly showed that this effect was mediated by mu-opioid receptors, which were up-regulated following repeated treatment of PF-3845. Our data add to the knowledge about changes in pain perception in obese subjects, revealing a key role of CB1 and mu-opioid receptors and their possible pharmacological crosstalk and reinforcing the need to consider this modulation in planning effective pain management for obese patients.