scholarly journals Energy homeostasis in apolipoprotein AIV and cholecystokinin-deficient mice

2017 ◽  
Vol 313 (5) ◽  
pp. R535-R548 ◽  
Author(s):  
Jonathan Weng ◽  
Danwen Lou ◽  
Stephen C. Benoit ◽  
Natalie Coschigano ◽  
Stephen C. Woods ◽  
...  

Apolipoprotein AIV (ApoAIV) and cholecystokinin (CCK) are well-known satiating signals that are stimulated by fat consumption. Peripheral ApoAIV and CCK interact to prolong satiating signals. In the present study, we hypothesized that ApoAIV and CCK control energy homeostasis in response to high-fat diet feeding. To test this hypothesis, energy homeostasis in ApoAIV and CCK double knockout (ApoAIV/CCK-KO), ApoAIV knockout (ApoAIV-KO), and CCK knockout (CCK-KO) mice were monitored. When animals were maintained on a low-fat diet, ApoAIV/CCK-KO, ApoAIV-KO, and CCK-KO mice had comparable energy intake and expenditure, body weight, fat mass, fat absorption, and plasma parameters relative to the controls. In contrast, these KO mice exhibited impaired lipid transport to epididymal fat pads in response to intraduodenal infusion of dietary lipids. Furthermore, ApoAIV-KO mice had upregulated levels of CCK receptor 2 (CCK2R) in the small intestine while ApoAIV/CCK-KO mice had upregulated levels of CCK2R in the brown adipose tissue. After 20 wk of a high-fat diet, ApoAIV-KO and CCK-KO mice had comparable body weight and fat mass, as well as lower energy expenditure at some time points. However, ApoAIV/CCK-KO mice exhibited reduced body weight and adiposity relative to wild-type mice, despite having normal food intake. Furthermore, ApoAIV/CCK-KO mice displayed normal fat absorption and locomotor activity, as well as enhanced energy expenditure. These observations suggest that mice lacking ApoAIV and CCK have reduced body weight and adiposity, possibly due to impaired lipid transport and elevated energy expenditure.

2014 ◽  
Vol 221 (3) ◽  
pp. 381-390 ◽  
Author(s):  
Gustavo W Fernandes ◽  
Cintia B Ueta ◽  
Tatiane L Fonseca ◽  
Cecilia H A Gouveia ◽  
Carmen L Lancellotti ◽  
...  

Three types of beta adrenergic receptors (ARβ1–3) mediate the sympathetic activation of brown adipose tissue (BAT), the key thermogenic site for mice which is also present in adult humans. In this study, we evaluated adaptive thermogenesis and metabolic profile of a mouse withArβ2knockout (ARβ2KO). At room temperature, ARβ2KO mice have normal core temperature and, upon acute cold exposure (4 °C for 4 h), ARβ2KO mice accelerate energy expenditure normally and attempt to maintain body temperature. ARβ2KO mice also exhibited normal interscapular BAT thermal profiles during a 30-min infusion of norepinephrine or dobutamine, possibly due to marked elevation of interscapular BAT (iBAT) and ofArβ1, andArβ3mRNA levels. In addition, ARβ2KO mice exhibit similar body weight, adiposity, fasting plasma glucose, cholesterol, and triglycerides when compared with WT controls, but exhibit marked fasting hyperinsulinemia and elevation in hepaticPepck(Pck1) mRNA levels. The animals were fed a high-fat diet (40% fat) for 6 weeks, ARβ2KO mice doubled their caloric intake, accelerated energy expenditure, and inducedUcp1expression in a manner similar to WT controls, exhibiting a similar body weight gain and increase in the size of white adipocytes to the WT controls. However, ARβ2KO mice maintain fasting hyperglycemia as compared with WT controls despite very elevated insulin levels, but similar degrees of liver steatosis and hyperlipidemia. In conclusion, inactivation of the ARβ2KO pathway preserves cold- and diet-induced adaptive thermogenesis but disrupts glucose homeostasis possibly by accelerating hepatic glucose production and insulin secretion. Feeding on a high-fat diet worsens the metabolic imbalance, with significant fasting hyperglycemia but similar liver structure and lipid profile to the WT controls.


Endocrinology ◽  
2016 ◽  
Vol 157 (4) ◽  
pp. 1457-1466 ◽  
Author(s):  
Miyuki Shibata ◽  
Ryoichi Banno ◽  
Mariko Sugiyama ◽  
Takashi Tominaga ◽  
Takeshi Onoue ◽  
...  

Abstract Agouti-related protein (AgRP) expressed in the arcuate nucleus is a potent orexigenic neuropeptide, which increases food intake and reduces energy expenditure resulting in increases in body weight (BW). Glucocorticoids, key hormones that regulate energy balance, have been shown in rodents to regulate the expression of AgRP. In this study, we generated AgRP-specific glucocorticoid receptor (GR)-deficient (knockout [KO]) mice. Female and male KO mice on a high-fat diet (HFD) showed decreases in BW at the age of 6 weeks compared with wild-type mice, and the differences remained significant until 16 weeks old. The degree of resistance to diet-induced obesity was more robust in female than in male mice. On a chow diet, the female KO mice showed slightly but significantly attenuated weight gain compared with wild-type mice after 11 weeks, whereas there were no significant differences in BW in males between genotypes. Visceral fat pad mass was significantly decreased in female KO mice on HFD, whereas there were no significant differences in lean body mass between genotypes. Although food intake was similar between genotypes, oxygen consumption was significantly increased in female KO mice on HFD. In addition, the uncoupling protein-1 expression in the brown adipose tissues was increased in KO mice. These data demonstrate that the absence of GR signaling in AgRP neurons resulted in increases in energy expenditure accompanied by decreases in adiposity in mice fed HFD, indicating that GR signaling in AgRP neurons suppresses energy expenditure under HFD conditions.


Endocrinology ◽  
2014 ◽  
Vol 156 (2) ◽  
pp. 411-418 ◽  
Author(s):  
Pierre Cardinal ◽  
Luigi Bellocchio ◽  
Omar Guzmán-Quevedo ◽  
Caroline André ◽  
Samantha Clark ◽  
...  

The paraventricular nucleus of the hypothalamus (PVN) regulates energy balance by modulating not only food intake, but also energy expenditure (EE) and brown adipose tissue thermogenesis. To test the hypothesis that cannabinoid type 1 (CB1) receptor in PVN neurons might control these processes, we used the Cre/loxP system to delete CB1 from single-minded 1 (Sim1) neurons, which account for the majority of PVN neurons. On standard chow, mice lacking CB1 receptor in Sim1 neurons (Sim1-CB1-knockout [KO]) had food intake, body weight, adiposity, glucose metabolism, and EE comparable with wild-type (WT) (Sim1-CB1-WT) littermates. However, maintenance on a high-fat diet revealed a gene-by-diet interaction whereby Sim1-CB1-KO mice had decreased adiposity, improved insulin sensitivity, and increased EE, whereas feeding behavior was similar to Sim1-CB1-WT mice. Additionally, high-fat diet-fed Sim1-CB1-KO mice had increased mRNA expression of the β3-adrenergic receptor, as well as of uncoupling protein-1, cytochrome-c oxidase subunit IV and mitochondrial transcription factor A in the brown adipose tissue, all molecular changes suggestive of increased thermogenesis. Pharmacological studies using β-blockers suggested that modulation of β-adrenergic transmission play an important role in determining EE changes observed in Sim1-CB1-KO. Finally, chemical sympathectomy abolished the obesity-resistant phenotype of Sim1-CB1-KO mice. Altogether, these findings reveal a diet-dependent dissociation in the CB1 receptor control of food intake and EE, likely mediated by the PVN, where CB1 receptors on Sim1-positive neurons do not impact food intake but hinder EE during dietary environmental challenges that promote body weight gain.


2019 ◽  
Vol 317 (5) ◽  
pp. E783-E793
Author(s):  
Danielle Zecharia ◽  
Maayan Rauch ◽  
Adi Sharabi-Nov ◽  
Snait Tamir ◽  
Roee Gutman

Perturbations in postnatal leptin signaling have been associated with altered susceptibility to diet-induced obesity (DIO) under high-fat-diet (HFD), albeit with contradicting evidence. Previous studies have shown that alpha murine urokinase-type plasminogen activator (αMUPA) mice have a higher and longer postnatal leptin surge compared with their wild types (WTs) as well as lower body weight and food intake under regular diet (RD). Here we explored αMUPA's propensity for DIO and the effect of attenuating postnatal leptin signaling with leptin antagonist (LA) on energy homeostasis under both RD and HFD. Four-day-old αMUPA pups were treated on alternate days until postnatal day 18 with either vehicle or LA (10 or 20 mg·day−1·kg−1) and weaned into RD or HFD. Compared with RD-fed αMUPA males, HFD-fed αMUPA males showed higher energy intake, even when corrected for body weight difference, and became hyperinsulinemic and obese. Additionally, HFD-fed αMUPA males gained body weight at a higher rate than their WTs mainly because of strain differences in energy expenditure. LA administration did not affect strain differences under RD but attenuated αMUPA’s hyperinsulinemia and DIO under HFD, most likely by mediating energy expenditure. Together with our previous findings, these results suggest that αMUPA’s leptin surge underlies its higher susceptibility to obesity under HFD, highlighting the role of leptin-related developmental processes in inducing obesity in a postweaning obesogenic environment, at least in αMUPA males. This study therefore supports the use of αMUPA mice for elucidating developmental mechanisms of obesity and the efficacy of early-life manipulations via leptin surge axis in attenuating DIO.


Author(s):  
Farouk K El-baz ◽  
Hanan F Aly

 Objective: This study was carried out to investigate the potential of Dunaliella salina microalgae to ameliorate obesity induced by high-fat diet (HFD) in male Wistar rats.Methods: Fifty rats weighing 150–160 g were fed HFD for 12 weeks. The rats were randomly divided into five groups of ten rats each. Obese rats were orally administered D. salina ethanolic extract (150 mg/Kg body weight), and orlistat as standard drug (12 mg/Kg body weight), for 6 weeks.Results: Treatment of obese rats with both D. salina and orlistat had a significant effect in reducing body and liver weights as well as visceral fat, inhibiting pancreatic lipase activity, decreased lipid profile, and increased fecal fat and ameliorating liver function enzymes activity, insulin, blood glucose, and leptin levels. Besides, food intake was insignificantly increased as a result of D. salina and orlistat treatments compared with normal control rats.Conclusion: It could be concluded that D. salina rich in β-carotene significantly reduced body weight gain and ameliorated several metabolic pathways implicated in obesity and its related complication. Hence, further intensive study must be carried out to formulate D. Salina extracts to apply as a promising natural anti-obesity nutraceutical drug.


2018 ◽  
Vol 19 (10) ◽  
pp. 3281 ◽  
Author(s):  
Youngmi Lee ◽  
Eun-Young Kwon ◽  
Myung-Sook Choi

Isoliquiritigenin (ILG) is a flavonoid constituent of Glycyrrhizae plants. The current study investigated the effects of ILG on diet-induced obesity and metabolic diseases. C57BL/6J mice were fed a normal diet (AIN-76 purified diet), high-fat diet (40 kcal% fat), and high-fat diet +0.02% (w/w) ILG for 16 weeks. Supplementation of ILG resulted in decreased body fat mass and plasma cholesterol level. ILG ameliorated hepatic steatosis by suppressing the expression of hepatic lipogenesis genes and hepatic triglyceride and fatty acid contents, while enhancing β-oxidation in the liver. ILG improved insulin resistance by lowering plasma glucose and insulin levels. This was also demonstrated by the intraperitoneal glucose tolerance test (IPGTT). Additionally, ILG upregulated the expression of insulin signaling-related genes in the liver and muscle. Interestingly, ILG elevated energy expenditure by increasing the expression of thermogenesis genes, which is linked to stimulated mitochondrial biogenesis and uncoupled cellular respiration in brown adipose tissue. ILG also suppressed proinflammatory cytokine levels in the plasma. These results suggest that ILG supplemented at 0.02% in the diet can ameliorate body fat mass, plasma cholesterol, non-alcoholic fatty liver disease, and insulin resistance; these effects were partly mediated by increasing energy expenditure in high-fat fed mice.


2017 ◽  
Vol 52 (3) ◽  
pp. 174
Author(s):  
Purwo Sri Rejeki ◽  
Harjanto Harjanto ◽  
Raden Argarini ◽  
Imam Subadi

The aim of this study was to determine the comparative effects of EA (EA) on the CV12, ST36 and ST40 to weight gain prevention over the short-term regulation of energy balance. The study was conducted with a completely randomized design. Rats were divided into five groups: negative control group (no treatment, n=5), positive control (sham EA/back, n=5), EA CV 12 (n=6), EA ST 36 (n=6) and EA ST 40 (n=7). Rats were exposed to high-fat diet for two weeks and EA was simultaneously performed once daily, five days a week for two weeks with 2 Hz, for 10 minutes with continuous wave. Body weight, BMI, front limb circumference and rear were measured during study. Levels of blood glucose, cholesterol, triglycerides, LDL and HDL were measured at the end of the study; which reflects the short-term regulation of energy homeostasis. For weight loss, EA CV12, ST36 and ST40 group have lost weight significantly compared to the negative and positive control group. The ST40 group has a significant decrease than ST36 and CV12. The most significant decrease in BMI found in the ST40 group. EA did not affect blood glucose levels, but modulated blood lipid profile. In ST 40 group there was a significant decrease in cholesterol, LDL and triglycerides. EA at point ST 40 is potential in preventing increased body weight and BMI in rats exposed to high-fat diet compared to the CV 12 and ST 36. ST 40 is a point with a potential of lowering LDL and triglycerides serum so that it can play a role in the short term regulation of energy homeostasis but also in the prevention of dyslipidemia.


Circulation ◽  
2020 ◽  
Vol 142 (Suppl_3) ◽  
Author(s):  
Maria Pini

Introduction: Sedentary lifestyle and excessive calorie intake are risk factors for CVD. We have demonstrated the cardioprotective effect of exercise in aged mice and the critical role of visceral adiposity and its profibrotic secretome in increasing cardiovascular risks in obesity and aging. The association between exercise, lowered plasma leptin and reduced inflammatory leukocytes has been recently shown in patients with atherosclerosis. It remains unclear whether elevated plasma leptin can preserve or alter cardiovascular function in obesity. Methods: We analyzed the effect of high fat diet (HFD) in C57BL/6J male mice on the heart in terms of function, structure, histology and key molecular markers. Two interventions were used: 1) active fat mass loss via exercise (daily swimming) during HFD; 2) passive fat mass loss via surgical removal of the visceral adipose tissue (VAT lipectomy) followed by HFD. Results: HFD increased body weight and adiposity, leading to higher plasma leptin, glucose and insulin levels, compared to control diet (CD) mice. HFD impaired left ventricle (LV) structure (hypertrophy, interstitial fibrosis) and cardiac function (echocardiography, in vivo hemodynamics). Atria of HFD mice had enhanced pro-inflammatory protein production. Exercise reduced circulating leptin levels in HFD mice by 50%, in line with fat mass loss. In contrast, lipectomy reduced visceral fat mass, but body weight, adiposity and plasma leptin did not change. Both exercise and VAT lipectomy improved cardiac contractility, reversed collagen deposition and oxidative stress in HFD mice. Both interventions downregulated LV pro-inflammatory markers. We proved the role of leptin in cardiac remodeling in vitro by incubating primary cardiac fibroblasts with hyperleptinemic plasma from HFD mice. Remarkably, plasma from HFD-EX (exercise) suppressed the fibro-proliferative and pro-inflammatory responses of cardiac fibroblasts. Conclusions: Leptin directly contribute to cardiac fibrosis in obesity via activation and proliferation of cardiac fibroblasts. Understanding how leptin signals to the heart might have implications in a wide range of CVD, potentially helping early stratification and personalized care.


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