Liat Shbiro

Development of obesity in the Otsuka Long-Evans Tokushima Fatty rat

Understanding the early factors affecting obesity development in males and females may help to prevent obesity and may lead to the discovery of more effective treatments for those already obese. The Otsuka Long-Evans Tokushima Fatty (OLETF) rat model of obesity is characterized by hyperphagia-induced obesity, due to a spontaneous lack of CCK(1) receptors. In the present study, we focused on the behavioral and physiological aspects of obesity development from weaning to adulthood. We examined body weight, feeding efficiency, fat pad [brown, retroperitoneal, inguinal and epydidimal (in males)] weight, inguinal adipocyte size and number, leptin and oxytocin levels, body mass index, waist circumference, and females estrous cycle structure. In the males, central hypothalamic gene expression was also examined. OLETF rats presented overall higher fat and leptin levels, larger adipocytes, and increased waist circumference and BMI from weaning until adulthood, compared with controls. Analysis of developmental patterns of gene expression for hypothalamic neuropeptides revealed peptide-specific patterns that may underlie or be a consequence of the obesity development. Analysis of the developmental trajectories toward obesity within the OLETF strain revealed that OLETF females developed obesity in a more gradual manner than the males, presenting delayed obesity-related turning points, with reduced adipocyte size but larger postweaning fat pads and increased adipocyte hyperplasia compared with the males. Intake decrease in estrus vs. proestrus was significantly less in OLETF vs. Long-Evans Tokushima Otsuka females. The findings highlight the importance of using different sex-appropriate approaches to increase the efficacy of therapeutic interventions in the treatment and prevention of chronic early-onset obesity.

Toward an animal model of childhood-onset obesity: follow-up of OLETF rats during pregnancy and lactation

The Otsuka Long-Evans Tokushima Fatty (OLETF) rat model of obesity (a spontaneous CCK1 receptor knockout) has been extensively studied as model of hyperphagia-induced obesity. In previous studies, young OLETF rats presented abnormal eating patterns [compared with Long-Evans Tokushima Otsuka (LETO) controls] in a variety of independent ingestion and nursing tests during the suckling period. The aim of the present study was to characterize the early emergence of abnormal adiposity in the pups. Moreover, because both the dams and the pups present the genetic mutation, a close follow-up of the dams body weight and intake during pregnancy and lactation was performed to examine the circumstances that contribute to build up the pups early adiposity. Compared with controls, OLETF pups presented higher fat levels, larger adipocytes, and increased waist circumference as early as postnatal day 7 and this profile persisted to the age of weaning. While LETO dams gained weight throughout pregnancy and lactation, OLETF dams were obese and hyperphagic during pregnancy but lost weight during lactation, probably as a result of rearing hyperphagic pups. Current and previous results suggest a possible influence of the dams obesity during gestation and a high investment in nursing time during lactation on the pups obesity levels during childhood. This, combined with the innate hyperphagia repeatedly observed in the pups at these early ages, makes the OLETF strain a useful tool in the research of childhood-onset obesity.

Post-weaning voluntary exercise exerts long-term moderation of adiposity in males but not in females in an animal model of early-onset obesity.

Given the alarming increase in childhood, adolescent and adult obesity there is an imperative need for understanding the early factors affecting obesity and for treatments that may help prevent or at least moderate it. Exercise is frequently considered as an effective treatment for obesity however the empirical literature includes many conflicting findings. In the present study, we used the OLETF rat model of early-onset hyperphagia-induced obesity to examine the influence of early exercise on peripheral adiposity-related parameters in both males and females. Rats were provided voluntary access to running wheels from postnatal day (PND) 22 until PND45. We examined fat pad weight (brown, retroperitoneal, inguinal and epididymal); inguinal adipocyte size and number; and leptin, adiponectin, corticosterone and creatinine levels. We also examined body weight, feeding efficiency and spontaneous intake. Early voluntary exercise reduced intake, adiposity and leptin in the OLETF males following a sharp reduction in adipocyte size despite a significant increase in fat cell number. Exercising males from the lean LETO control strain presented stable intake, but reduced body fat, feeding efficiency and increased plasma creatinine, suggesting an increment in muscle mass. OLETF females showed reduced feeding efficiency and liver fat, and a significant increase in brown fat. Exercising LETO control females increased intake, body weight and creatinine, but no changes in body fat. Overall, OLETF rats presented higher adiponectin levels than controls in both basal and post-exercise conditions. The results suggest an effective early time frame, when OLETF males can be successfully re-programmed through voluntary exercise; in OLETF females the effect is much more moderate. Findings expose sex-dependent peripheral mechanisms in coping with energy challenges.

Prohedonic Effect of Cannabidiol in a Rat Model of Depression.

Background: Accumulating evidence suggests that cannabidiol (CBD) may be an effective and safe anxiolytic agent and potentially also an antidepressant. Aim: The objective of this study was to further examine these properties of CBD using the ‘depressive-like Wistar-Kyoto (WKY) rat, focusing on the drugs effect on anhedonia-like behaviors. Methods: Forty-eight WKY and 48 control Wistar adult male rats were pretreated orally with CBD (15, 30 and 45 mg/kg) or vehicle. The saccharin preference test (SPT), the elevated plus maze (EPM) test and the novel object exploration (NOE) test were used. Results: CBD showed a prohedonic effect on the WKY rats at 30 mg/kg in the SPT. In the NOE, CBD increased exploration of the novel object and locomotion at 45 mg/kg and increased locomotion at 15 mg/kg, indicating an improvement in the characteristically low motivation of WKY rats to explore. There was no similar effect at any dose in the EPM or in open-field behavior in the habituation to the NOE. Conclusions: These findings extend the limited knowledge on the antidepressant effect of CBD, now shown for the first time in a genetic animal model of depression. These results suggest that CBD may be beneficial for the treatment of clinical depression and other states with prominent anhedonia.

Genetic vulnerability, timing of short-term stress and mood regulation: A rodent diffusion tensor imaging study

UNLABELLEDnEarly stressful life events predict depression and anxiety in carriers of specific polymorphisms and alter brain responses but brain structural phenotypes are largely unknown. We studied the interaction between short-term stress during specific time-windows and emotion-regulation using a genetic animal model of depression, the Wistar-Kyoto (WKY) rat. Brain structural alterations were analyzed using Diffusion Tensor Imaging (DTI). WKY (n=49) and Wistar (n=55) rats were divided into experimental groups: Early stress (ES): From postnatal day (PND) 27 rats were exposed to three consecutive days of stressors; Late stress (LS): From PND 44 rats were exposed to the same protocol;nnnCONTROLnNo stressors. From PND 50, all animals were behaviorally tested for levels of anxiety and despair-like behaviors and then scanned. Gene×Environment×Timing (G×E×T) interactions (p=0.00022 after Hochberg correction) were found in ventral orbital cortex, cingulate cortex, external capsule, amygdala and dentate gyrus and in the emotion regulation measures. WKY showed longer immobility in forced swim test, but no effect of ES was detected. ES increased open-field anxiety-like behaviors in Wistar rats but not in WKY, possibly indicating a ceiling effect in WKY. Stress in pre-pubertal or adolescent phases in development may influence structural integrity of specific brain regions and emotion regulation behaviors depending on genetic vulnerability, consistent with a G×E×T interaction in mood dysregulation.

Maternal Environmental Contribution to Adult Sensitivity and Resistance to Obesity in Long Evans Rats

Background The OLETF rat is an animal model of early onset hyperphagia induced obesity, presenting multiple pre-obese characteristics during the suckling period. In the present study, we used a cross-fostering strategy to assess whether interactions with obese dams in the postnatal environment contributed to the development of obesity. Methodology On postnatal Day (PND)-1 OLETF and control LETO pups were cross-fostered to same or opposite strain dams. An independent ingestion test was performed on PND11 and a nursing test on PND18. Rats were sacrificed at weaning or on PND90, and plasma leptin, insulin, cholesterol, triglycerides and alanine aminotransferase (ALT) were assayed. Fat pads were collected and weighed and adipocyte size and number were estimated. Body weight and intake, as well as the estrous cycle of the female offspring were monitored. Principal Findings During the suckling period, the pups phenotype was almost completely determined by the strain of the mother. However, pups independently ingested food according to their genotype, regardless of their actual phenotype. At adulthood, cross fostered males of both strains and LETO females were affected in regard of their adiposity levels in the direction of the foster dam. On the other hand, OLETF females showed almost no alterations in adiposity but were affected by the strain of the dams in parameters related to the metabolic syndrome. Thus, OLETF females showed reduced liver adiposity and circulating levels of ALT, while LETO females presented a disrupted estrous cycle and increased cholesterol and triglycerides in the long term. Conclusions The present study provides further support for the early postnatal environment playing a sex-divergent role in programming later life phenotype. In addition, it plays a more central role in determining the functioning of mechanisms involved in energy balance that may provide protection from or sensitivity to later life obesity and pathologies related to the metabolic syndrome.

Medical use of cannabis and cannabinoids containing products – Regulations in Europe and North America

In 1937, the United States of America criminalized the use of cannabis and as a result its use decreased rapidly. In recent decades, there is a growing interest in the wide range of medical uses of cannabis and its constituents; however, the laws and regulations are substantially different between countries. Laws differentiate between raw herbal cannabis, cannabis extracts, and cannabinoid-based medicines. Both the European Medicines Agency (EMA) and the United States Food and Drug Administration (FDA) do not approve the use of herbal cannabis or its extracts. The FDA approved several cannabinoid-based medicines, so did 23 European countries and Canada. However, only four of the reviewed countries have fully authorized the medical use of herbal cannabis - Canada, Germany, Israel and the Netherlands, together with more than 50% of the states in the United States. Most of the regulators allow the physicians to decide what specific indications they will prescribe cannabis for, but some regulators dictate only specific indications. The aim of this article is to review the current (as of November 2017) regulations of medical cannabis use in Europe and North America.

Fibre tract analysis using diffusion tensor imaging reveals aberrant connectivity in a rat model of depression

Abstract Objectives: Abnormal brain connectivity has been described in depressive disorder. However, these studies are correlational or cross-sectional and their design does not examine causal relationships. We aimed to investigate structural connectivity in a genetic rat model of depression. Methods: Using diffusion tensor imaging (DTI), we reconstructed white matter tracts and analysed fractional anisotropy (FA) and diffusivity indices (mean, axial and radial) to investigate structural connectivity in fibre tracts implicated in major depression: the corpus callosum, fornix, cingulum and anterior commissures. Results: Tractography-based analysis revealed that, compared to Wistar control rats, the Wistar–Kyoto strain (WKY) rat model of depression exhibited decreased connectivity, manifested by decreased FA in the corpus callosum, right and left anterior commissures. A statistical trend of decreased FA was observed in both the right and left cingulum. Increased diffusivity (mean diffusion) was detected in both the corpus callosum and the fornix of WKY rats compared to controls. Voxel-based analysis confirmed differences between WKY and controls in the regions investigated. Conclusions: Decreased connectivity in a genetic rat model of depression corroborates the findings in patients suffering from major depression suggesting that the vulnerability for developing depression is mainly polygenic and less likely to be due to childhood adversity per se.

Prospective analysis of safety and efficacy of medical cannabis in large unselected population of patients with cancer

BACKGROUNDnCancer is a major public health problem as the leading cause of death. Palliative treatment aimed to alleviate pain and nausea in patients with advanced disease is a cornerstone of oncology. In 2007, the Israeli Ministry of Health began providing approvals for medical cannabis for the palliation of cancer symptoms. The aim of this study is to characterize the epidemiology of cancer patients receiving medical cannabis treatment and describe the safety and efficacy of this therapy.nnnMETHODSnWe analyzed the data routinely collected as part of the treatment program of 2970 cancer patients treated with medical cannabis between 2015 and 2017.nnnRESULTSnThe average age was 59.5u202f±u202f16.3u202fyears, 54.6% women and 26.7% of the patients reported previous experience with cannabis. The most frequent types of cancer were: breast (20.7%), lung (13.6%), pancreatic (8.1%) and colorectal (7.9%) with 51.2% being at stage 4. The main symptoms requiring therapy were: sleep problems (78.4%), pain (77.7%, median intensity 8/10), weakness (72.7%), nausea (64.6%) and lack of appetite (48.9%). After six months of follow up, 902 patients (24.9%) died and 682 (18.8%) stopped the treatment. Of the remaining, 1211 (60.6%) responded; 95.9% reported an improvement in their condition, 45 patients (3.7%) reported no change and four patients (0.3%) reported deterioration in their medical condition.nnnCONCLUSIONSnCannabis as a palliative treatment for cancer patients seems to be well tolerated, effective and safe option to help patients cope with the malignancy related symptoms.

Attenuated Weight Gain with the Novel Analog of Olanzapine Linked to Sarcosinyl Moiety (PGW5) Compared to Olanzapine.

Olanzapine-induced weight gain is associated with atherosclerosis, hypertension, dyslipidemia, and diabetes. We synthesized a novel antipsychotic drug (PGW5) possessing an olanzapine moiety linked to sarcosine, a glycine transporter 1 inhibitor. In this study, we compared the metabolic effects of PGW5 and olanzapine in a female rat model of weight gain. Female rats were treated daily with oral olanzapine (4xa0mg/kg), PGW5 (25xa0mg/kg), or vehicle for 16xa0days. Behavioral tests were conducted on days 12–14. Biochemical analyses were performed at the end of the treatment. A significant increase in body weight was observed in the olanzapine-treated group, while the PGW5 group did not differ from the controls. The open field test showed hypo-locomotion in the olanzapine-treated animals as compared to PGW5 and control groups. A significant increase in hypothalamic protein expression of the neuropeptide Y5 receptor and a decrease in pro-opiomelanocortin messenger ribonucleic acid (mRNA) levels were detected following PGW5 treatment, but not after olanzapine administration. PGW5 appears to possess minor metabolic effects compared with the parent compound olanzapine. The differential modulation of brain peptides associated with appetite regulation is possibly involved in the attenuation of metabolic effects by PGW5.