Changes In Energy Expenditure Research Articles

Metabolic Consequences of Exposure to Maternal High Fat Diet in Offspring

The increased risk for obesity in offspring born to obese mothers may be driven by changes in energy expenditure. To examine the effects of maternal high fat diet (HFD)‐induced obesity on offspring energy expenditure, female C57BL6/J mice were fed a control (17% fat, TD95092) or HFD (45% fat, TD8811) ad libitum for 12 weeks prior to and during pregnancy and during lactation. Female mice were bred with lean male mice at 17 wk of age. At weaning, male offspring from control and HFD‐dams were randomized to control (C) or HFD (H), provided ad libitum, generating 4 groups of offspring: CC, CH, HC, and HH, where the first letter corresponds to maternal diet and the second to offspring post‐weaning diet. At 20 weeks of age, energy intake and expenditure (EE) were assessed in male offspring over 48 h using the Promethion Continuous Indirect Calorimetry system (Sable Systems). HFD consumption in offspring was associated with reduced respiratory exchange ratio (RER, CC vs CH: 0.89±0.02 vs 0.82±0.02; p<0.01, n=13–16). There was no effect of maternal HFD on offspring RER (CC vs HC, p= 0.66; CH vs HH, p=0.54). To examine the effect of maternal HFD on offspring energy expenditure, ANCOVA using offspring total body weight (measured at the beginning of the indirect calorimety experiment) as a covariate for the 48 h recording period (both light and dark cycles) was performed. When comparing the effect of maternal HFD in offspring fed either a control diet (CC vs HC) or HFD (HC vs HH) postweaning, the covariate (offspring total body weight) significantly predicted EE for both comparisons (CC vs HC, p<0.05; HC vs HH, p = 0.05), while there was no significant effect of maternal diet on EE. Offspring food intake (in both light and dark cycles) was not altered by maternal HFD (CC vs HC, p=0.22; CH vs HH, p=0.21). In control‐fed offspring, maternal HFD had no effect on body weight at 20 wk of age (CC vs CH, 26.84±0.79g vs 28.91±1.03g, p=0.12), while in HFD‐fed offspring, males exposed to maternal HFD were significantly heavier than males from control‐fed dams (CH vs HH, 33.81±1.46g vs 38.42±1.59g, p=0.04). The observed changes in RER indicate that offspring post‐weaning HFD, but not maternal HFD, is associated with a shift in substrate utilization, specifically with increased fat oxidation in response to post‐weaning HFD. In the context of maternal HFD, the EE data suggest that offspring total body weight, and not maternal obesity may be driving offspring changes in energy expenditure.Support or Funding InformationUSDA ARIS Project 6026‐51000‐010‐05SThis abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Resolution of Hypothyroidism Restores Cold-Induced Thermogenesis in Humans.

Background: Hypothyroidism is a frequent endocrine disorder with common symptoms of increased cold sensitivity and unintended weight gain, indicating changes in energy expenditure (EE) and response to cold exposure. Thyroid hormones (TH) play an important role for proper function of brown adipose tissue (BAT) and cold-induced thermogenesis (CIT) in rodents, but the role of hypothyroidism on CIT in humans is uncertain.Methods: This was a prospective observational study. Forty-two patients presenting with subclinical or overt hypothyroidism in whom TH replacement was planned were recruited. Thirty-three patients completed the study. Thermogenesis was measured by indirect calorimetry during warm conditions and after a mild cold stimulus of 90 minutes, both during the hypothyroid state and after at least three months of sufficient TH replacement. CIT was determined as the difference between EE during mildly cold and warm conditions. The primary endpoint was the change of CIT between the hypothyroid and euthyroid state.Results: EE during warm conditions increased from a median of 1330 (interquartile range [IQR] 1251–1433) kcal/24 hours in the hypothyroid state to a median of 1442 (IQR 1294–1579) kcal/24 hours in the euthyroid state (+8.5%; p = 0.0002). EE during mild cold exposure increased from 1399 (IQR 1346–1571) kcal/24 hours to 1610 (IQR 1455–1674) kcal/24 hours (+15%; p < 0.0001). The median CIT was 55 (IQR 1–128) kcal/24 hours at the baseline visit, after restoration of euthyroidism CIT increased by 102% to a median of 111 (IQR 15.5–200) kcal/24 hours (p = 0.011). Serum levels of free thyroxine at the respective visit and mean outdoor temperature during the preceeding 30 days were significantly associated with CIT (p = 0.021 and p = 0.001, respectively).Conclusion: Restoring euthyroidism significantly increases CIT in hypothyroid humans.

Chemogenetic activation of orexin/hypocretin neurons ameliorates aging-induced changes in behavior and energy expenditure.

Aging affects numerous physiological processes, as well as behavior. A large number of these processes are regulated, at least partially, by hypothalamic orexin neurons, and orexin tone may decrease with normal aging. In this study, we hypothesized that designer receptors exclusively activated by designer drugs (DREADD) stimulation of orexin neuronal activity will ameliorate the effect of aging on behavioral and metabolic alterations in young and middle-aged mice. DREADD targeting was achieved by stereotaxic injection of AAV vectors (AAV2-hSyn-DIO-hM3D(Gq)-mCherry) into the lateral hypothalamus of 5- and 12-mo old orexin-cre female mice and was confirmed by immunohistochemistry (IHC) analysis of orexin A and mCherry expression. After recovery, animals were subjected to a behavioral test battery consisting of the elevated plus maze (EPM), open field (OFT), and novel object recognition tests (NORT) to assess effects of aging on anxiety-like behavior, general locomotion, and working memory. A comprehensive laboratory animal monitoring system (CLAMS) was used to measure spontaneous physical activity (SPA) and energy expenditure (EE). The results indicate that activation of orexin neurons mitigates aging-induced reductions in anxiety-like behavior in middle-aged mice (P < 0.005) and increases locomotion in both young and middle-aged mice (P < 0.05). Activation of orexin neurons increases SPA (P < 0.01) and EE (P < 0.005) in middle-aged mice, restoring the levels to that observed in young animals. Results from this study identify orexin neurons as potential therapeutic targets for age-related impairments in cognitive and anxiety-related behavior, and energy balance.

Obesity and Polycystic Ovary Syndrome: Implications for Pathogenesis and Novel Management Strategies.

Polycystic ovary syndrome (PCOS) is a common female condition typified by reproductive, hyperandrogenic, and metabolic features. Polycystic ovary syndrome is a genetic condition, exacerbated by obesity. There is a close link between obesity and PCOS based on epidemiological data, and more recently corroborated through genetic studies. There are many mechanisms mediating the effects of weight-gain and obesity on the development of PCOS. The metabolic effects of insulin resistance and steroidogenic and reproductive effects of hyperinsulinaemia are important mechanisms. Adipokine production by subcutaneous and visceral fat appears to play a part in metabolic function. However, given the complexity of PCOS pathogenesis, it is important also to consider possible effects of PCOS on further weight-gain, or at least on hampering attempts at weight-loss and maintenance through lifestyle changes. Possible mediators of these effects include changes in energy expenditure, mental ill health, or physical inactivity. In this brief review, we discuss the main mechanisms that underlie the association between obesity and PCOS, from divergent perspectives of weight-gain contributing to development of PCOS and vice versa. We also consider novel management options for women with obesity and PCOS.

Physical activity patterns associated with a pedagogical intervention in six to eight year old children in an urban school

This study evaluated changes in energy expenditure in six to eight-year-old children after a two year pedagogical intervention on healthy habits. Methods: This was a longitudinal descriptive observ...

Dynamic Energy Balance and Obesity Prevention.

Dynamic energy balance can give clinicians important answers for why obesity is so resistant to control. When food intake is reduced for weight control, all components of energy expenditure change, including metabolic rate at rest (resting energy expenditure [REE]), metabolic rate of exercise, and adaptive thermogenesis. This means that a change in energy intake influences energy expenditure in a dynamic way. Mechanisms associated with reduction of total energy expenditure following weight loss are likely to be related to decreased body mass and enhanced metabolic efficiency. Reducing calorie intake results in a decrease in body weight, initially with a marked reduction in fat free mass and a decrease in REE, and this change is maintained for several years in a reduced state. Metabolic adaptation, which is not explained by changes in body composition, lasts for more than several years. These are powerful physiological adaptations that induce weight regain. To avoid a typically observed weight-loss and regain trajectory, realistic weight loss goals should be established and maintained for more than 1 year. Using a mathematical model can help clinicians formulate advice about diet control. It is important to emphasize steady efforts for several years to maintain reduced weight over efforts to lose weight. Because obesity is difficult to reverse, clinicians must prioritize obesity prevention. Obesity prevention strategies should have high feasibility, broad population reach, and relatively low cost, especially for young children who have the smallest energy gaps to change.

Targeting lifestyle energy expenditure in the management of obesity and health: from biology to built environment.

Increasing lifestyle energy expenditure has long been advocated in the prevention and treatment of obesity, as embodied in the ancient prescription of Hippocrates (the 'father of modern medicine') that people with obesity should eat less and exercise more. However, the long-term outcome of exercise alone or in combination with dieting in obesity management is poor. To understand the reasons underlying these failures and to develop novel strategies that target lifestyle energy expenditure in both prevention and treatment of obesity, research over the past decades has focused on (i) the interactions between physical activity and body weight (and its composition) throughout the lifespan; (ii) the influence of biology and potential compensatory changes in energy expenditure, food intake and food assimilation in response to energy deficits; and (iii) the impact of the built environment (outdoor and indoor) and smart technology on physical activity behaviours, thermoregulatory thermogenesis and metabolic health. It is against this background that recent advances relevant to the theme of 'Targeting Lifestyle Energy Expenditure in the Management of Obesity and Health: From Biology to Built Environment' are addressed in this overview and the nine review articles in this supplement, reporting the proceedings of the 9th Fribourg Obesity Research Conference.

Effects of a low carbohydrate diet on energy expenditure during weight loss maintenance: randomized trial

ObjectiveTo determine the effects of diets varying in carbohydrate to fat ratio on total energy expenditure.DesignRandomized trial.SettingMulticenter collaboration at US two sites, August 2014 to May 2017.Participants164 adults aged 18-65...

A carnosine analog mitigates metabolic disorders of obesity by reducing carbonyl stress.

Sugar- and lipid-derived aldehydes are reactive carbonyl species (RCS) frequently used as surrogate markers of oxidative stress in obesity. A pathogenic role for RCS in metabolic diseases of obesity remains controversial, however, partly because of their highly diffuse and broad reactivity and the lack of specific RCS-scavenging therapies. Naturally occurring histidine dipeptides (e.g., anserine and carnosine) show RCS reactivity, but their therapeutic potential in humans is limited by serum carnosinases. Here, we present the rational design, characterization, and pharmacological evaluation of carnosinol, i.e., (2S)-2-(3-amino propanoylamino)-3-(1H-imidazol-5-yl)propanol, a derivative of carnosine with high oral bioavailability that is resistant to carnosinases. Carnosinol displayed a suitable ADMET (absorption, distribution, metabolism, excretion, and toxicity) profile and was determined to have the greatest potency and selectivity toward α,β-unsaturated aldehydes (e.g., 4-hydroxynonenal, HNE, ACR) among all others reported thus far. In rodent models of diet-induced obesity and metabolic syndrome, carnosinol dose-dependently attenuated HNE adduct formation in liver and skeletal muscle, while simultaneously mitigating inflammation, dyslipidemia, insulin resistance, and steatohepatitis. These improvements in metabolic parameters with carnosinol were not due to changes in energy expenditure, physical activity, adiposity, or body weight. Collectively, our findings illustrate a pathogenic role for RCS in obesity-related metabolic disorders and provide validation for a promising new class of carbonyl-scavenging therapeutic compounds rationally derived from carnosine.

Brown adipose tissue, energy expenditure, and biomarkers of cardio-metabolic health among the Yakut (Sakha) of northeastern Siberia.

This study provides the first investigation of non-shivering thermogenesis (NST) and brown adipose tissue (BAT) activity among an indigenous circumpolar population, the Yakut of northeastern Siberia. The study also examines the health significance of BAT activity in this population by testing the relationships between BAT thermogenesis and biomarkers of cardio-metabolic disease risk, such as percent body fat and blood glucose and cholesterol levels. Data were collected in the Sakha Republic (Yakutia) for 31 men and 43 women. Change in energy expenditure and BAT thermogenesis were quantified after a 30-minute mild cooling condition. Anthropometric dimensions, blood glucose, and lipid levels were also collected. On average, the skin temperature of the supraclavicular area was constant after cooling while the skin temperature of a point on the sternum dropped significantly (P < .001), thus suggesting the presence of active supraclavicular BAT among Yakut adults. Participants with evidence of greater BAT thermogenesis exhibited a larger percent change in energy expenditure (% ΔEE) and an increase in respiratory quotient (RQ) after cooling (P ≤ .05). While there was no relationship between BAT activity and blood lipid levels, BAT thermogenesis was positively associated with blood glucose levels (P < .01). Yakut adults exhibit evidence of active BAT deposits. Given that there is a significant relationship between BAT activity and % ΔEE, it is possible that BAT plays a role in NST among Yakut adults. While the relationship between BAT and body composition is inconclusive, participants with greater BAT seemed to preferentially utilize glucose during cold stress exposure.

The impact of pulmonary rehabilitation on severe physical inactivity in patients with chronic obstructive pulmonary disease: a pilot study.

IntroductionIn patients with COPD, severe physical inactivity (SPI, which is defined as total daily energy expenditure/resting energy expenditure; physical activity level [PAL] ratio, <1.4) is associated with increased morbidity and mortality. Pulmonary rehabilitation (PR) increases physical capacity in COPD, but the impact on SPI is unknown. In this study, we aimed at elucidating the prevalence of SPI in COPD patients attending standard PR, the impact of PR on SPI prevalence, and the relationship between SPI and time spent in moderate physical activity thus whether American College of Sports Medicine (ACSM) recommendations are clinically useful in excluding SPI in COPD.MethodsThis is a prospective non-interventional pilot study on patients with COPD completing PR, consenting to wear an accelerometer (Sensewear© Armband) for a week before and after completing PR to assess changes in energy expenditure, time spent in physical activity, and number of daily steps. Low level of daily physical activity was not an inclusion criterion.ResultsIn total, 57 patients completed the study and 31 (54%) had SPI at baseline. In patients with SPI, baseline median FEV1 was 48 (range, 28–86) % of predicted and GOLD B, n=11 (35%)/GOLD D, n=20 (65%). Surprisingly, 31 of SPI patients (97%) spent ≥150 minutes/week in moderate physical activity. After rehabilitation, 24 (78%) did not change activity level and were persistently SPI. We observed no differences at baseline between patient responding (n=7) vs not responding (n=24) to PR. Responders increased number of daily steps and time spent in lighter but not moderate physical activity during rehabilitation.ConclusionIn this pilot study, SPI was prevalent, and PR had limited impact. Contraintui-tively, most patients with SPI complied with general recommendations of weekly hours spent in moderate physical activity. Our study highlights that increasing time spent in light activity rather than improving time spent in moderate activity is important in COPD patients with chronic dyspnea.

Poor agreement between indirect calorimetry and predictive formula of rest energy expenditure in pre-dialytic and dialytic chronic kidney disease

Protein-energy wasting (PEW) is common in the end-stage of chronic kidney disease (CKD) and can be caused by factors related to poor dietary intake and changes in energy expenditure. Indirect calorimetry (IC) is the gold standard method to measure resting energy expenditure (REE), however, it is not much available and it is common to use predictive formulas of REE in clinical practice. This study compared the values of REE measured by IC to those estimated by Harris & Benedict formula, the most one used in clinical practice in Brazil. Patients with stage 5 CKD (an estimated glomerular filtration rate <15mL/min/1.73m2), >18 years old were included and submitted to the IC test and Harris & Benedict's predictive formula. The assessments were performed at three moments: pre-dialysis indications (P1), at the beginning of dialysis indication (P2) and 30 days after the start of dialysis therapy (P3). Tuckey's test was used to compare energy expenditure variable by groups, and the Bland & Altman analysis was used to compare the agreement between the methods. A significance level of p<0.05 and agreement limits of up to 200Kcal were used. Thirty-five patients with mean age of 61.2±10.9 years were included, 60% female, 17% afrodescendants and 60% with diabetes mellitus. There were no significant differences in REE between the three moments (P1: 1289.8±382.7kcal, P2: 1218.2±362.8kcal, P3: 1269.5±335.1kcal, p=0.874). Harris & Benedict formula did not show IC agreement for the REE measurement because it presented high limits of agreement or because of the low precision of the estimated measure. This study showed that there was no significant alteration of REE by IC and that REE values estimated by Harris & Benedict formula did not agree with the values measured by IC in this population. The role of Harris & Benedict formula should be re-evaluated in stage 5 CKD patients.

Changes in Energy Expenditure, Dietary Intake, and Energy Availability Across an Entire Collegiate Women's Basketball Season.

Zanders, BR, Currier, BS, Harty, PS, Zabriskie, HA, Smith, CR, Stecker, RA, Richmond, SR, Jagim, AR, and Kerksick, CM. Changes in energy expenditure, dietary intake, and energy availability across an entire collegiate women's basketball season. J Strength Cond Res 35(3): 804-810, 2021-The purpose of this study was to identify changes in energy expenditure and dietary intake across an entire women's basketball season. On 5 different occasions across the competitive season, female collegiate basketball players (19.8 ± 1.3 years, 173.9 ± 13.6 cm, 74.6 ± 9.1 kg, 27.1 ± 3.2% fat, 53.9 ± 6.4 ml·kg-1·min-1, n = 13) were outfitted with heart rate and activity monitors over 4 consecutive days and completed 4-day food and fluid records to assess changes in energy expenditure and dietary status. Dual-energy x-ray absorptiometry was used to assess baseline body composition and resting energy expenditure (REE) was measured before and after the season. Data were analyzed using 1-factor repeated-measures analysis of variance. Total daily energy expenditure (TDEE, p = 0.059) and physical activity levels (TDEE/REE, p = 0.060) both tended to decrease throughout the season. Energy balance was negative at all time points throughout the season. Absolute and normalized daily protein intake at the end of the season was significantly (p < 0.05) lower than at the beginning of the season. Carbohydrate (3.7 ± 0.4 g·kg-1·d-1) and protein (1.17 ± 0.16 g·kg-1·d-1) intakes were lower than commonly recommended values based on previously published guidelines. These findings suggest that greater education and interventions for collegiate athletes and coaches regarding dietary intake and energy expenditure are warranted.

Abstract P324: Role of GABAergic Signaling in AgRP Neurons in the Dipsogenic and Metabolic Responses to Brain Angiotensin

Obesity is a major risk factor for development of hypertension, and evidence supports a role for the suppression of resting metabolic rate (RMR) in the development and maintenance of obesity. Angiotensin II (ANG) AT1A receptors, localized to cells expressing the leptin receptor and Agouti-related peptide (AgRP) within the arcuate nucleus of the hypothalamus (ARC), are involved in transcriptional control of AgRP and γ-aminobutyric acid (GABA) synthetic genes ( Gad65 , Gad67 , Slc32a1 ) within the ARC, as well as the integrative control of thermogenic sympathetic nerve activity (SNA) and RMR responses in vivo to various stimuli including leptin and high fat diet. These data led us to hypothesize that AT1A functions to suppress GABA signaling in AgRP neurons, ultimately to disinhibit SNA and RMR. Treatment of cultured mouse hypothalamic N43/5 cells (which express endogenous Agtr1a , AgRP and Gad67 ) with 100 nM ANG for 1 hour (n=6) resulted in reduced AgRP (0.57-fold of control, p=0.03) and Gad67 (0.72-fold of control, p=0.09) mRNA. Mice with targeted disruption of Slc32a1 (vesicular GABA transporter; VGAT) in AgRP neurons (VGAT AgRP-KO mice) were generated on a mixed background. Compared to littermates (male n=9-17, female n=7-8), VGAT AgRP-KO mice (male n=8-13, female n=2-3) at 8 weeks of age exhibited normal body mass (genotype p=ns, sex p&lt;0.05, interaction p=ns), no changes in food intake (genotype p=ns, sex p=ns, interaction p=ns), but a sex-dependent genotype effect on fluid intake was observed (male con 4.5±0.3 vs KO 5.1±0.4; fem con 5.1±0.4 vs KO 3.7±0.6 mL/d; interaction p&lt;0.05). A preliminary study of male mice instrumented for chronic infusion of ANG (5 ng/hr, 21 days icv) was also performed. This caused modest increases in drinking (con+aCSF n=7, 3.3±0.8, con+ANG n=4, 5.2±1.0, KO+ANG n=3, 7.9±1.1 mL/d, p&lt;0.05) but no change in energy efficiency (11.2±2.9, 11.3±3.5, 10.1±4.1 mg/kcal), indicating no change in energy expenditure, possibly due to the mixed background of this strain. We conclude that ANG acts at AgRP cells of the ARC to suppress GABA and AgRP signaling, and this contributes to energy and fluid homeostasis in a complex, strain- and sex-dependent manner.

Salinity Variation in a Mangrove Ecosystem: A Physiological Investigation to Assess Potential Consequences of Salinity Disturbances on Mangrove Crabs.

Dimitri Theuerkauff, Georgina A. Rivera-Ingraham, Jonathan A.C. Roques, Laurence Azzopardi, Marine Bertini, Mathilde Lejeune, Emilie Farcy, Jehan-Hervé Lignot, and Elliott Sucré (2018) Salinity is one of the main environmental factors determining coastal species distribution. However, in the specific case of mangrove crabs, salinity selection cannot be understood through ecological approaches alone. Yet understanding this issue is crucial in the context of mangrove conservation, since this ecosystem is often used as biofilter of (low- salinity) wastewater. Crabs are keystone species in this mangrove ecosystem and are differentially affected by salinity. We hypothesize that crab salinity selection may be partly explained by specific salinity-induced physiological constraints associated with osmoregulation, energy and redox homeostasis. To test this, the response to salinity variation was analysed in two landward mangrove crabs: the fiddler crab Tubuca urvillei, which inhabits low-salinity areas of the mangrove, and the red mangrove crab Neosarmatium meinerti, which lives in areas with higher salinity. Results confirm that both species are strong hypo-/hyper-osmoregulators that deal easily with large salinity variations. Such shifts in salinity do not induce changes in energy expenditure (measured as oxygen consumption) or in the production of reactive oxygen species. However, T. urvillei is physiologically suited to habitats with brackish water, since it presents i) high hemolymph osmolalities over a wider range of salinities and lower osmoregulatory capacity in seawater, ii) high Na+/K+-ATPase (NKA) activity in the posterior osmoregulatory gills and iii) a thicker osmoregulatory epithelium along the posterior gill lamellae. Therefore, while environmental salinity alone cannot directly explain fiddler and red mangrove crab distributions, our data suggest that salinity selection is indeed influenced by specific physiological adjustments.

Physical activity, energy expenditure and sedentary parameters in overfeeding studies - a systematic review

BackgroundIt has been proposed that compensations in physical activity, energy expenditure and sedentary parameters can occur as a result of overfeeding studies in order to maintain body weight; however, the evidence has not yet been systematically reviewed.MethodsThe current study systematically reviewed the literature on this subject to determine the common tools used in overfeeding studies and to explore whether overfeeding produces changes in physical activity, energy expenditure and sedentary parameters. Eight electronic databases were searched to identify experimental studies using keywords pertaining to overfeeding, exercise, physical activity and sedentariness. Articles included healthy adults (aged 18–64 years) participating in an overfeeding study that examined at least one parameter of sedentary, energy expenditure or physical activity. Of 123 full-text articles reviewed, 15 met the inclusion criteria.ResultsThe common tools used in overfeeding studies were doubly labeled water (n = 6), room calorimeter (n = 4), accelerometer (n = 7), pedometer (n = 3), radar sensor (n = 4) and survey (n = 1). Parameters partaining to energy expenditure increased between 7 to 50% with different overfeeding duration. Physical activity parameters, such as number of steps and spontaneous activity, increased or decreased significantly in three studies, while five studies showed no significant change. Sedentary parameters were examined by only one study and its results were not significant after 3 days of overfeeding. Methodological issues existed concerning the small number of studies, disparities in sedentary and physical activity parameters and various definitions of free-living experimental conditions and physical activity limits.ConclusionsThere is actually a use of many tools and a large variation of parameters for physical activity in overfeeding studies. Contradictory findings showed changes in physical activity parameters following overfeeding and limited findings support the absence of changes in sedentariness. While energy expenditure parameters are more numerous and all show an increase after an overfeeding period, further studies are required to confirm changes in physical activity and sedentary parameters.

High plasma apolipoprotein B identifies obese subjects who best ameliorate white adipose tissue dysfunction and glucose-induced hyperinsulinemia after a hypocaloric diet

To optimize the prevention of type 2 diabetes (T2D), high-risk obese subjects with the best metabolic recovery after a hypocaloric diet should be targeted. Apolipoprotein B lipoproteins (apoB lipoproteins) induce white adipose tissue (WAT) dysfunction, which in turn promotes postprandial hypertriglyceridemia, insulin resistance (IR), and hyperinsulinemia. The aim of this study was to explore whether high plasma apoB, or number of plasma apoB lipoproteins, identifies subjects who best ameliorate WAT dysfunction and related risk factors after a hypocaloric diet. Fifty-nine men and postmenopausal women [mean ± SD age: 58±6 y; body mass index (kg/m2): 32.6±4.6] completed a prospective study with a 6-mo hypocaloric diet (-500 kcal/d). Glucose-induced insulin secretion (GIIS) and insulin sensitivity (IS) were measured by 1-h intravenous glucose-tolerance test (IVGTT) followed by a 3-h hyperinsulinemic-euglycemic clamp, respectively. Ex vivo gynoid WAT function (i.e., hydrolysis and storage of 3H-triolein-labeled triglyceride-rich lipoproteins) and 6-h postprandial plasma clearance of a 13C-triolein-labeled high-fat meal were measured in a subsample (n=25). Postintervention first-phase GIISIVGTT and total C-peptide secretion decreased in both sexes, whereas second-phase and total GIISIVGTT and clamp IS were ameliorated in men (P<0.05). Baseline plasma apoB was associated with a postintervention increase in WAT function (r=0.61) and IS (glucose infusion rate divided by steady state insulin (M/Iclamp) r=0.30) and a decrease in first-phase, second-phase, and total GIISIVGTT (r=-0.30 to -0.35) without sex differences. The association with postintervention amelioration in WAT function and GIISIVGTT was independent of plasma cholesterol (total, LDL, and HDL), sex, and changes in body composition. Subjects with high baseline plasma apoB (1.2±0.2 g/L) showed a significant increase in WAT function (+105%; P=0.012) and a decrease in total GIISIVGTT (-34%; P≤0.001), whereas sex-matched subjects with low plasma apoB (0.7±0.1 g/L) did not, despite equivalent changes in body composition and energy intake and expenditure. High plasma apoB identifies obese subjects who best ameliorate WAT dysfunction and glucose-induced hyperinsulinemia, independent of changes in adiposity after consumption of a hypocaloric diet. We propose that subjects with high plasma apoB represent an optimal target group for the primary prevention of T2D by hypocaloric diets. This trial was registered at BioMed Central as ISRCTN14476404.

Hypothalamic Spexin and Galanin Receptor 2 Are Novel Regulators of Energy Balance in Mice

Spexin is a novel neuropeptide discovered by bioinformatics and has been proposed as a regulator of energy balance. However, its precise role and underlying mechanisms remain unclear. In this study, we investigated the role of spexin and its receptor, galanin receptor 2 (GALR2), in regulation of energy balance in the mediobasal hypothalamus of mice. Administration of spexin into the third ventricle near the hypothalamus (I3V) significantly decreased food intake and body weight with no change in energy expenditure in mice. The central spexin-induced anorexia and weight loss were reinstated by pre-I3V administration of GALR2 antagonist, M871, indicating hypothalamic GALR2-mediated action of spexin in the regulation of energy balance. In addition, we showed that I3V administration of spexin-based selective GALR2 agonist significantly reduced food intake and body weight in a dose-dependent manner with no signs of illness assessed by a conditioned taste aversion test, suggesting a novel role of hypothalamic GALR2 in the regulation of energy balance. Furthermore, we found that activation of GALR2 induced by spexin increased phosphorylation of CREB in the mediobasal hypothalamus of mice and cells overexpressing GALR2 different from galanin, suggesting a ligand-dependent switch of G protein coupled with GALR2. Taken together, these results suggested a critical role of hypothalamic spexin and GALR2 in the regulation of energy balance in mice. Disclosure N. Ha: None. N. Kim: None. C. Kim: None. M. Song: None. H. Lee: None. B. Jin: None. M. Park: None. J. Seong: None. S. Kim: None. D. Kim: None.

Activity seascapes highlight central place foraging strategies in marine predators that never stop swimming

BackgroundCentral place foragers (CPF) rest within a central place, and theory predicts that distance of patches from this central place sets the outer limits of the foraging arena. Many marine ectothermic predators behave like CPF animals, but never stop swimming, suggesting that predators will incur ‘travelling’ costs while resting. Currently, it is unknown how these CPF predators behave or how modulation of behavior contributes to daily energy budgets. We combine acoustic telemetry, multi-sensor loggers, and hidden Markov models (HMMs) to generate ‘activity seascapes’, which combine space use with patterns of activity, for reef sharks (blacktip reef and grey reef sharks) at an unfished Pacific atoll.ResultsSharks of both species occupied a central place during the day within deeper, cooler water where they were less active, and became more active over a larger area at night in shallower water. However, video cameras on two grey reef sharks revealed foraging attempts/success occurring throughout the day, and that multiple sharks were refuging in common areas. A simple bioenergetics model for grey reef sharks predicted that diel changes in energy expenditure are primarily driven by changes in swim speed and not body temperature.ConclusionsWe provide a new method for simultaneously visualizing diel space use and behavior in marine predators, which does not require the simultaneous measure of both from each animal. We show that blacktip and grey reef sharks behave as CPFs, with diel changes in activity, horizontal and vertical space use. However, aspects of their foraging behavior may differ from other predictions of traditional CPF models. In particular, for species that never stop swimming, patch foraging times may be unrelated to patch travel distance.

Relationship between gait kinematics and walking energy expenditure during pregnancy in South African women

BackgroundVarious musculoskeletal changes occurring during pregnancy may lead to the change in gait and contribute to the increase in walking energy expenditure. Previous research indicates that changes in gait mechanics may lead to the increase in mechanical work required during walking. However, there is little information to indicate if changes in gait mechanics during pregnancy have impact on active or total energy expenditure. Therefore, the primary aim of this study was to investigate the relationship between changes in gait kinematics and walking energy expenditure in pregnant women.MethodsThirty-five women (mean age = 27.5 ± 6.1 years) volunteered for the study during various stages of pregnancy (1st trimester average = 12.1 ± 2.2 weeks; 2nd trimester = 22.3 ± 2.6 weeks; 3rd trimester = 31.4 ± 2.6 weeks). 3D motion analysis was used to assess changes in kinematic parameters during walking at self-selected pace. Resting metabolic rate, and walking energy expenditure expressed in terms of rate and cost of O2 were analysed with portable metabolic analyser.ResultsOnly medio-lateral deviation of centre of gravity (COGML) increased 13.6% between the 1st and 2nd, and 39.3% between 2nd and 3rd trimester (p ≤ 0.001). However, self-selected walking speed depicted strong significant positive linear relationship with net O2 rate (r = 0.70; p ≤ 0.001), and was strongly associated with the vertical excursion of the COG (r = 0.75, p ≤ 0.001).ConclusionsChanges in gait mechanics during pregnancy may lead to an increase in walking energy expenditure. However, the consequent increase in walking energy cost may not be sufficient to offset the natural energy sparing mechanism.