scholarly journals Effects of chronic weight perturbation on energy homeostasis and brain structure in mice

2011 ◽  
Vol 300 (6) ◽  
pp. R1352-R1362 ◽  
Author(s):  
Y. Ravussin ◽  
R. Gutman ◽  
S. Diano ◽  
M. Shanabrough ◽  
E. Borok ◽  
...  

Maintenance of reduced body weight in lean and obese human subjects results in the persistent decrease in energy expenditure below what can be accounted for by changes in body mass and composition. Genetic and developmental factors may determine a central nervous system (CNS)-mediated minimum threshold of somatic energy stores below which behavioral and metabolic compensations for weight loss are invoked. A critical question is whether this threshold can be altered by environmental influences and by what mechanisms such alterations might be achieved. We examined the bioenergetic, behavioral, and CNS structural responses to weight reduction of diet-induced obese (DIO) and never-obese (CON) C57BL/6J male mice. We found that weight-reduced (WR) DIO-WR and CON-WR animals showed reductions in energy expenditure, adjusted for body mass and composition, comparable (−10–15%) to those seen in human subjects. The proportion of excitatory synapses on arcuate nucleus proopiomelanocortin neurons was decreased by ∼50% in both DIO-WR and CON-WR mice. These data suggest that prolonged maintenance of an elevated body weight (fat) alters energy homeostatic systems to defend a higher level of body fat. The synaptic changes could provide a neural substrate for the disproportionate decline in energy expenditure in weight-reduced individuals. This response to chronic weight elevation may also occur in humans. The mouse model described here could help to identify the molecular/cellular mechanisms underlying both the defense mechanisms against sustained weight loss and the upward resetting of those mechanisms following sustained weight gain.

2019 ◽  
Vol 9 (10) ◽  
pp. 1388-1394
Author(s):  
Hong Deng ◽  
Wei Zhang ◽  
Dingguo Ruan ◽  
Dezhi Chen ◽  
Xiaoyang Xu ◽  
...  

Obesity is a modern disease and the cause is quite complicated. This study explores the effects of aerobic and resistance exercise on weight loss and their relationship with the PGC-1α/Irisin/UCP-1 signaling pathway. First, we selected 52 obese students for aerobic and resistance exercise. Second, we established an obesity rat model, and then subjected them to 12 weeks of aerobic and resistance exercise. The body weights and blood lipid contents of all the subjects were measured, and mRNA and protein expressions were determined via real-time PCR and western blot. In obese students, aerobic exercise and the combination of aerobic and resistance exercise significantly reduced body weight and blood lipid levels. In obese model rats, aerobic and resistance exercise significantly reduced the body weight, blood lipid levels, and increased the PGC-1, Irisin, and UCP-1 levels. Furthermore, the combined effects of aerobic and resistance exercise were similar to those of prolonged aerobic exercise in both human subjects and model rats. The mechanism of weight loss via aerobic and resistance exercise may be related to the PGC-1α/Irisin/UCP-1 pathway, and the combination of aerobic and resistance exercise may be a more suitable weight loss option for obese patients.


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.


2011 ◽  
Vol 301 (5) ◽  
pp. R1259-R1266 ◽  
Author(s):  
Kenneth M. Baldwin ◽  
Denis R. Joanisse ◽  
Fadia Haddad ◽  
Rochelle L. Goldsmith ◽  
Dympna Gallagher ◽  
...  

Maintenance of a 10% or greater reduced body weight results in decreases in the energy cost of low levels of physical activity beyond those attributable to the altered body weight. These changes in nonresting energy expenditure are due mainly to increased skeletal muscle work efficiency following weight loss and are reversed by the administration of the adipocyte-derived hormone leptin. We have also shown previously that the maintenance of a reduced weight is accompanied by a decrease in ratio of glycolytic (phosphofructokinase) to oxidative (cytochrome c oxidase) activity in vastus lateralis muscle that would suggest an increase in the relative expression of the myosin heavy chain I (MHC I) isoform. We performed analyses of vastus lateralis muscle needle biopsy samples to determine whether maintenance of an altered body weight was associated with changes in skeletal muscle metabolic properties as well as mRNA expression of different isoforms of the MHC and sarcoplasmic endoplasmic reticular Ca2+-dependent ATPase (SERCA) in subjects studied before weight loss and then again after losing 10% of their initial weight and receiving twice daily injections of either placebo or replacement leptin in a single blind crossover design. We found that the maintenance of a reduced body weight was associated with significant increases in the relative gene expression of MHC I mRNA that was reversed by the administration of leptin as well as an increase in the expression of SERCA2 that was not significantly affected by leptin. Leptin administration also resulted in a significant increase in the expression of the less MHC IIx isoform compared with subjects receiving placebo. These findings are consistent with the leptin-reversible increase in skeletal muscle chemomechanical work efficiency and decrease in the ratio of glycolytic/oxidative enzyme activities observed in subjects following dietary weight loss.


2020 ◽  
Vol 4 (Supplement_1) ◽  
Author(s):  
Luane da Guia Vieira ◽  
Alan Carlos Fernandes ◽  
Tais Nascimento ◽  
Suzelei de Castro França ◽  
Jose Antunes-Rodrigues ◽  
...  

Abstract POMC neurons expressed in the ARC are essential for energy balance and glucose homeostasis. It has been suggested the involvement of these neurons in the control of endocrine axes, such as the HPA. During fasting, POMCARC neurons are silenced as an effort to reduce body weight loss and to avoid hypoglycemia. During this process glucocorticoid secretion and activation of enzymes involved in the hepatic gluconeogenesis take place in order to preserve the homeostasis. In this study, to clarify the contribution of POMCARC neurons to the adaptive changes in energy homeostasis, glucose metabolism and HPA axis activity induced by food deprivation we used DREADDs to specifically activate POMCARC. Bilateral injections of the AAV carrying the excitatory DREADD (hM3DGq) or only the reporter gene (mCherry) have been performed into the ARC of Pomc-ires-cre and WT mice. Two weeks later the animals were fasted for 36hr, treated with saline (5 i.p. injections each 8hrs) and blood samples were collected from the facial vein at 10am. Two weeks apart, the same animals were submitted to another period of fasting and treated with CNO (1mg/Kg, 5 i.p. injections each 8hrs). Four hours after the last injection of CNO, the mice were anesthetized, blood and the liver were collected and then the animals perfused for brain harvesting. Body weight measurements have been performed before and after the 36hrs period of fasting. Another set of Pomc-ires-cre (hM3DGq or mCherry) and WT animals were fasted (36hrs), treated with CNO (5X) and subjected to GTT. DREADD–induced activation of POMCARC neurons has been confirmed by the increased cFos/mCherry expression after CNO treatment only in Pomc-ires-cre animals expressing hM3DGq. We observed that the specific activation of POMCARC neurons did not change the fasting-induced activation of HPA axis. Surprisingly, we observed reduced body weight loss and higher plasma glucose in Pomc-ires-cre animals expressing the hM3DGq and treated with CNO. The GTT showed an impaired glucose tolerance after activation of POMCARC neurons. The increased fasting glucose plasma levels was associated with increased G6pc (Glucose-6-phosphatase) mRNA expression but with no effect on other hepatic gluconeogenic genes. The present study reveals that POMCARC neurons are not involved in the increased HPA axis activity in prolonged fasting conditions. Considering the classical anorexigenic/thermogenic and the glucose-lowering action of POMCARC neurons, the present data reveal an unpredicted reduced body weight loss and impaired glucose tolerance induced by activation of these neurons during fasting. These data reinforce the notion that POMCARC neurons are heterogeneous and might be playing dual effects on energy homeostasis. Of note, because part of ARC neurons shares a common progenitor, some of the functions ascribed to POMC neurons could be mediated by non-POMC neurons expressing the Cre transgene.


2020 ◽  
Author(s):  
Wineke Bakker ◽  
Casper Gravesen Salinas ◽  
Monica Imbernon ◽  
Daniela Herrera Moro Chao ◽  
Rim Hassouna ◽  
...  

ABSTRACTThe control of body weight and glucose homeostasis are the bedrock of type 2 diabetes medication. Therapies based on co-administration of glucagon-like peptide-1 (GLP-1) long-acting analogues and insulin are becoming popular in the treatment of T2D. Both insulin and GLP-1 receptors (InsR and GLP1-R, respectively) are expressed in brain regions critically involved in the regulation of energy homeostasis, suggesting a possible cooperative action. However, the mechanisms underlying the synergistic action of insulin and GLP-1R agonists on body weight loss and glucose homeostasis remain largely under-investigated. In this study, we provide evidence that peripheral insulin administration modulates the action of GLP-1R agonists onto fatty acids oxidation. Taking advantage of fluorescently labeled insulin and GLP-1R agonists, we found that glucoprivic condition, either achieved by insulin or by 2-deoxyglucose (2-DG), acts as a permissive signal on the blood-brain barrier (BBB) at circumventricular organs, including the median eminence (ME) and the area postrema (AP), enhancing the passage and action of GLP-1-R agonists. Mechanistically, this phenomenon relied on the release of tanycyctic vascular endothelial growth factor A (VEGF-A) and it was selectively impaired after calorie-rich diet exposure. Finally, we found that in human subjects, low blood glucose also correlates with enhanced blood-to-brain passage of insulin suggesting that changes in glycaemia also affect passage of peptide hormones into the brain in humans.In conclusion, we describe a yet unappreciated mechanism by which acute variations of glycaemia gate the entry and action of circulating energy-related signals in the brain. This phenomenon has physiological and clinical relevance implying that glycemic control is critical to harnessing the full benefit of GLP-1R agonist co-treatment in body weight loss therapy.


1991 ◽  
Vol 81 (5) ◽  
pp. 635-644 ◽  
Author(s):  
Alan A. Connacher ◽  
William M. Bennet ◽  
Roland T. Jung ◽  
Dennis M. Bier ◽  
Christopher C. T. Smith ◽  
...  

1. Energy expenditure, plasma glucose and palmitate kinetics and leg glycerol release were determined simultaneously both before and during adrenaline infusion in lean and obese human subjects. Seven lean subjects (mean 96.5% of ideal body weight) were studied in the post-absorptive state and also during mixed nutrient liquid feeding, eight obese subjects (mean 165% of ideal body weight) were studied in the post-absorptive state and six obese subjects (mean 174% of ideal body weight) were studied during feeding. 2. Resting energy expenditure was higher in the obese subjects, but the thermic response to adrenaline, both in absolute and percentage terms, was similar in lean and obese subjects. Plasma adrenaline concentrations attained (3 nmol/l) were comparable in all groups and the infusion had no differential effects on the plasma insulin concentration. Before adrenaline infusion the plasma glucose flux was higher in the obese than in the lean subjects in the fed state only (45.8 ± 3.8 versus 36.6 ± 1.0 mmol/h, P <0.05); it increased to the same extent in both groups with the adrenaline infusion. 3. Before the adrenaline infusion plasma palmitate flux was higher in the obese than in the lean subjects (by 51%, P <0.01, in the post-absorptive state and by 78%, P <0.05, in the fed state). However, there was no significant change during adrenaline infusion in the obese subjects (from 13.5 ± 1.00 to 15.0 ± 1.84 mmol/h, not significant, in the post-absorptive state and from 14.4 ± 2.13 to 15.7 ± 1.74 mmol/h, not significant, in the fed state), whereas there were increases in the lean subjects (from 8.93 ± 1.10 to 11.2 ± 1.19 mmol/h, P <0.05, in the post-absorptive state, and from 8.06 ± 1.19 to 9.86 ± 0.93 mmol/h, P <0.05, in the fed state). 4. Before adrenaline infusion the palmitate oxidation rate was also higher in the obese than in the lean subjects (1.86 ± 0.14 versus 1.22 ± .09 mmol/h, P <0.01, in the post-absorptive state and 1,73 ± 0.25 versus 1.12 ± 0.12 mmol/h, P <0.05, in the fed state). However, in response to adrenaline the fractional oxidation rate (% of flux) increased less in the obese than in the lean subjects, especially in the post-absorptive state (from 13.8 ± 1.02 to 14.9 ± 1.39%, not significant, versus from 13.7 ± 0.98 to 19.3 ± 1.92%, P <0.05). These effects were independent of feeding. Leg glycerol release increased more in the lean subjects with adrenaline infusion, although increases in the plasma glycerol concentration did not differ between the groups. 5. These results suggest that in obese subjects plasma inter-organ transport of fatty acids and the subsequent fractional oxidation responses favour storage of triacylglycerol. These factors may be important determinants for the development and maintenance of the obese state.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Renata R. Braga ◽  
Barbara M. Crisol ◽  
Rafael S. Brícola ◽  
Marcella R. Sant’ana ◽  
Susana C. B. R. Nakandakari ◽  
...  

AbstractThe maintenance of mitochondrial activity in hypothalamic neurons is determinant to the control of energy homeostasis in mammals. Disturbs in the mitochondrial proteostasis can trigger the mitonuclear imbalance and mitochondrial unfolded protein response (UPRmt) to guarantee the mitochondrial integrity and function. However, the role of mitonuclear imbalance and UPRmt in hypothalamic cells are unclear. Combining the transcriptomic analyses from BXD mice database and in vivo experiments, we demonstrated that physical training alters the mitochondrial proteostasis in the hypothalamus of C57BL/6J mice. This physical training elicited the mitonuclear protein imbalance, increasing the mtCO-1/Atp5a ratio, which was accompanied by high levels of UPRmt markers in the hypothalamus. Also, physical training increased the maximum mitochondrial respiratory capacity in the brain. Interestingly, the transcriptomic analysis across several strains of the isogenic BXD mice revealed that hypothalamic mitochondrial DNA-encoded genes were negatively correlated with body weight and several genes related to the orexigenic response. As expected, physical training reduced body weight and food intake. Interestingly, we found an abundance of mt-CO1, a mitochondrial DNA-encoded protein, in NPY-producing neurons in the lateral hypothalamus nucleus of exercised mice. Collectively, our data demonstrated that physical training altered the mitochondrial proteostasis and induced the mitonuclear protein imbalance and UPRmt in hypothalamic cells.


2017 ◽  
Vol 313 (6) ◽  
pp. E731-E736 ◽  
Author(s):  
Wenjuan Wang ◽  
Xiangzhi Meng ◽  
Chun Yang ◽  
Dongliang Fang ◽  
Xuemeng Wang ◽  
...  

Loss of body weight and fat mass is one of the nonmotor symptoms of Parkinson’s disease (PD). Weight loss is due primarily to reduced energy intake and increased energy expenditure. Whereas inadequate energy intake in PD patients is caused mainly by appetite loss and impaired gastrointestinal absorption, the underlying mechanisms for increased energy expenditure remain largely unknown. Brown adipose tissue (BAT), a key thermogenic tissue in humans and other mammals, plays an important role in thermoregulation and energy metabolism; however, it has not been tested whether BAT is involved in the negative energy balance in PD. Here, using the 6-hydroxydopamine (6-OHDA) rat model of PD, we found that the activity of sympathetic nerve (SN), the expression of Ucp1 in BAT, and thermogenesis were increased in PD rats. BAT sympathetic denervation blocked sympathetic activity and decreased UCP1 expression in BAT and attenuated the loss of body weight in PD rats. Interestingly, sympathetic denervation of BAT was associated with decreased sympathetic tone and lipolysis in retroperitoneal and epididymal white adipose tissue. Our data suggeste that BAT-mediated thermogenesis may contribute to weight loss in PD.


2018 ◽  
Vol 73 (4) ◽  
pp. 290-301 ◽  
Author(s):  
Edyta Balejko ◽  
Jerzy Balejko ◽  
Dominika Plust

Obesity is the most common disease of affluence of the XXI century. According to WHO (World Health Organization), it is defined as a chronic metabolic disorder manifested by excessive accumulation of adipose tissue with high tendency for familial occurrence. According to WHO, obesity reaches epidemic proportions in many countries. High BMI (Body Mass Index) correlates with coexisting diseases. Traditional dietetic treatment often does not bring any results. A form of conservative (non-surgical) support for patients in fighting with obesity is the reduction of stomach volume by bioenteric intragastric balloon (BIB) treatment. The aim of the work was to develop a diet with anti-inflammatory properties, well-tolerated by the patients after BIB treatment. An American diet was modified by changing the composition of fatty acids, increasing anti-oxidative potential and adding synbiotics for patients treated with BIB. Chemical analysis of reconstructed food ratios of recommended diet was performed, analysing the content of micronutrients, composition of fatty acids, antioxidative capacity, reducing power and the content of polyphenols. Improvement in anthropometric measurement results and satisfying body weight loss were obtained, while preserving fat-free body mass. Improvement in the parameters of lipid metabolism was also observed, that is, decrease in total CH (cholesterol) and TG (triglycerides), and normalized concentration of HDL (high density lipoproteins) and LDL (low density lipoproteins) fractions. Reduced concentration of glucose in blood and lower blood pressure was also noted. Performed study confirms the effectiveness of complex treatment with BIB and properly adjusted individualized diet. Observations and own experience allow to deduce that patients who resign from systematic contact with a dietician cannot maintain reduced body weight. Abandoning previous habits is the only way to maintain the effect of weight loss. Most importantly, the change in patients’ awareness and consequent behaviour in the future are crucial. Even though genes may contribute to obesity, environmental factors mainly determine the possibility of the disease to occur. Therefore, the change of patients’ lifestyle after body weight reduction will decide on their fate.


2021 ◽  
Author(s):  
Ada Admin ◽  
David M Presby ◽  
Michael C Rudolph ◽  
Vanessa D Sherk ◽  
Matthew R Jackman ◽  
...  

Moderate weight loss improves numerous risk factors for cardiometabolic disease; however, long-term weight loss maintenance (WLM) is often thwarted by metabolic adaptations that suppress energy expenditure and facilitate weight regain. Skeletal muscle has a prominent role in energy homeostasis; therefore, we investigated the effect of WLM and weight regain on skeletal muscle in rodents. In skeletal muscle of obesity-prone rats, WLM reduced fat oxidative capacity and downregulated genes involved in fat metabolism. Interestingly, even after weight was regained, genes involved in fat metabolism genes were also reduced. We then subjected mice with skeletal muscle lipoprotein lipase overexpression (mCK-hLPL), which augments fat metabolism, to WLM and weight regain and found that mCK-hLPL attenuates weight regain by potentiating energy expenditure. Irrespective of genotype, weight regain suppressed dietary fat oxidation and downregulated genes involved in fat metabolism in skeletal muscle. However, mCK-hLPL mice oxidized more fat throughout weight regain and had greater expression of genes involved in fat metabolism and lower expression of genes involved in carbohydrate metabolism during WLM and regain. In summary, these results suggest that skeletal muscle fat oxidation is reduced during WLM and regain, and therapies that improve skeletal muscle fat metabolism may attenuate rapid weight regain.


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