Visceral fat mass determination in rodent: validation of dual-energy x-ray absorptiometry and anthropometric techniques in fat and lean rats

<p>Abstract</p> <p>Background</p> <p>Because abdominal obesity is predisposed to various metabolic disorders, it is of major importance to assess and track the changes with time of this specific fat mass. The main issue for clinicians or researchers is to use techniques for assessing abdominal fat deposition and its accumulation or changes over time, without sacrificing of experimental subjects. In the rat, techniques to investigate in-vivo visceral fat mass are lacking. The purpose of the study was to validate indirect Dual-energy X-ray Absorptiometry technique and abdominal circumference measurement as tools to predict visceral adipose tissue in rats.</p> <p>Forty-three Wistar male rats from different body weight, fat mass and ages were included in the study. Visceral fat mass was assessed by weighing the total perirenal and peri-epididymal adipose tissues after dissection. Statistical methods were used to discriminate the best region of interest allowing the in-vivo measure of Central Fat Mass by DXA. Abdominal circumference was measured at the same time as the DXA scan.</p> <p>Results</p> <p>A region of interest including Central Fat Mass from the whole body DXA scan (extending from L2 to L5 vertebrae), correlated strongly with <it>ex-vivo </it>Fat Mass (r = 0.94, p < 0.001). Abdominal circumference correlated significantly with <it>ex-vivo </it>Fat Mass (r = 0.82, p < 0.001) and Central Fat Mass (0.90, p < 0.001) in the whole group of rats. When dividing the whole group into lean and fat rats, correlations remained significant between Central Fat Mass and <it>ex-vivo </it>Fat Mass but disappeared for the lean group between abdominal circumference and <it>ex-vivo </it>Fat Mass.</p> <p>Conclusions</p> <p>This study validates the Central Fat Mass determined by DXA as a non-sacrificial technique to assess visceral fat for in-vivo investigations in rats. The abdominal circumference measure appears useful in studying overweight or obese rats. These two techniques could be convenient tools in follow-up and longitudinal studies.</p

Impact of an obesogenic diet program on bone densitometry, micro architecture and metabolism in male rat.

International audienceABSTRACT: Background The relationships between fat mass and bone tissue are complex and not fully elucidated. A high-fat/high-sucrose diet has been shown to induce harmful effects on bone micro architecture and bone biomechanics of rat. When such diet leads to obesity, it may induce an improvement of biomechanical bone parameters in rodent. Here, we examined the impact of a high-fat/high-sucrose diet on the body composition and its resulting effects on bone density and structure in male rats. Forty three Wistar rats aged 7 months were split into 3 groups: 1 sacrificed before diet (BD, n=14); 1 subjected to 16 weeks of high-fat/high-sucrose diet (HF/HS, n=14); 1 subjected to standard diet (Control, n=15). Abdominal circumference and insulin sensitivity were measured and visceral fat mass was weighed. The bone mineral density (BMD) was analyzed at the whole body and tibia by densitometry. Microcomputed tomography and histomorphometric analysis were performed at L2 vertebrae and tibiae to study the trabecular and cortical bone structures and the bone cell activities. Osteocalcin and CTX levels were performed to assess the relative balance of the bone formation and resorption. Differences between groups have been tested with an ANOVA with subsequent Scheffe post-hoc test. An ANCOVA with global mass and global fat as covariates was used to determine the potential implication of the resulting mechanical loading on bone. RESULTS: The HF/HS group had higher body mass, fat masses and abdominal circumference and developed an impaired glucose tolerance compared to Control group (p<0.001). Whole body bone mass (p<0.001) and BMD (p<0.05) were higher in HF/HS group vs. Control group. The trabecular thickness at vertebrae and the cortical porosity of tibia were improved (p<0.05) in HF/HS group. Bone formation was predominant in HF/HS group while an unbalance bone favoring bone resorption was observed in the controls. The HF/HS and Control groups had higher total and abdominal fat masses and altered bone parameters vs. BD group. Conclusions The HF/HS diet had induced obesity and impaired glucose tolerance. These changes resulted in an improvement of quantitative, qualitative and metabolic bone parameters. The fat mass increase partly explained these observations

Long-term effects of high intensity resistance and endurance exercise on plasma leptin and ghrelin in overweight individuals:the RESOLVE Study

International audienceThe objective of this study was to evaluate the effects of high-intensity resistance and endurance exercise on body composition and plasma leptin and ghrelin concentrations in overweight individuals. One hundred participants were randomly assigned to 3 exercise interventions: high-resistance–low-aerobic exercise (Re), low-resistance–high-aerobic exercise (rE), low-resistance–low-aerobic exercise (re). Interventions began with 3 weeks of residential supervision (phase 1) after which participants had to manage the physical activity programs individually (phase 2). Body composition and plasma variables were measured at baseline and after phase 1 as well as after 3, 6, and 12 months. Significant decreases in body weight and fat were observed after phase 1 (p < 0.001) and continued at a lower rate for up to 3 months and then remained stable for the rest of the protocol. Once a body weight plateau was reached, body fat loss after the Re and rE conditions exceeded the fat loss observed in the re condition by 1.5–2 kg (p < 0.05). Leptin was significantly decreased after day 21 and month 3 (p < 0.001) and remained stable for the rest of the study. Ghrelin was significantly increased after day 21 and month 3 (p < 0.001) and returned to a level comparable to baseline between month 6 and 12 when body weight and fat had reached a plateau. In conclusion, this study reinforces the idea that an increase in exercise intensity may accentuate body fat loss before the occurrence of a body weight plateau. Resistance to further fat loss was accompanied by a decrease in plasma leptin and an increase in plasma ghrelin

Implications des transporteurs du lactate dans les altérations du métabolisme lactique dans les états d'insulinorésistance (effets de l'activité physique et de la perte de poids)

MONTPELLIER-BU Médecine UPM (341722108) / SudocPARIS-BIUP (751062107) / SudocMONTPELLIER-BU Médecine (341722104) / SudocSudocFranceF

Effets de l’utilisation de vélo-bureaux à l’école sur les fonctions exécutives, les capacités physiques et la composition corporelle chez les enfants de primaire : Une étude pilote intra-sujet (BICLASS)

Context: Physical inactivity and sedentary behaviors are associated with adverse health outcomes in both adults and children. The purpose of this study was to investigate the effects of a 9 weeks program using a Cycle Desk during school time in primary school French children from high or low socio economic status (SES) on body composition, physical fitness (PF) and executive functions. Methods: Seventy-five children completed a test battery before (T0) and after 9 weeks of use of Cycle Desk (T1) evaluating their anthropometric characteristics, body composition, PF and executive functions. Results: Body mass index increased significantly, while body fat decreased after the use of Cycle Desks. Specifically, lean mass increased in the high-SES group while it decreased in the low-SES group. Performances on PF and executive functions tests increased significantly after 9 weeks of use of Cycle Desk. More specifically, the low-SES group had a greater improvement in PF between T0 and T1, compared to the high-SES group. Regarding executive functions, the high-SES group had a greater improvement in performance at T1 compared to the low-SES group. Conclusion: The promotion of low-intensity PA with the use of Cycle Desk at school, seems to be an interesting strategy in the fight against adverse effects of sedentary behaviour among children. Moreover, this strategy appears to be particularly effective in children of low SES.Effets de l'utilisation de vélo-bureaux à l'école sur les fonctions exécutives, les capacités physiques et la composition corporelle chez les enfants de primaire : Une étude pilote intra-sujet (BICLASS

Obese but not lean adolescents spontaneously decrease energy intake after intensive exercise

AbstractBackground Acute intensive exercise has been shown to induce a decreased subsequent daily energy intake in obese adolescents without altering the subjective appetite feelings. It is however unclear whether or not those nutritional adaptations to acute exercise are affected by the adolescents' weight status. The aim of this study was to compare the energy intake and macronutrient preferences, appetite feeling and energy expenditure response to acute exercise between lean and obese adolescents. Methods Ten obese and nine normal weight 12-15 year old adolescents randomly completed a session with a 30 minute cycling exercise at 75% VO2max and a sedentary session. During both sessions energy expenditure was assessed using Armband, ad libitum energy intake measured by weighing at both lunch and dinner time and appetite feelings assessed using visual analog scales. Results Daily, morning and afternoon energy expenditure were significantly higher in obese than in normal weight adolescents (p 0.05) but not in lean adolescents. No group or condition effects were observed on subjective appetite feelings. Discussion Post exercise spontaneous energy intake and energy expenditure are reduced in obese but not in normal weight adolescents, without appetite feeling changes. Acute exercise may have a greater impact on energy balance through the induced decreased energy intake in the absence of significant change in energy expenditure in obese youth

The Effects of Imposed Sedentary Behavior and Exercise on Energy Intake in Adolescents With Obesity

Objective: Exercise has been shown to decrease subsequent energy intake, without modification of appetite, in adolescents who are obese. This study compared the impact of acute exercise with imposed sedentary behaviors on the daily nutritional adaptations and energy balance of youths with obesity. Methods: Body composition and maximal oxygen uptake were assessed in 10 12- to 15-year-old adolescents with obesity. Energy consumption, appetite, and energy expenditure were assessed during 3 experimental sessions: (1) exercise session (EX), (2) bed rest session (BR), and (3) control session (CON). Results: Total and morning energy expenditures were significantly higher during EX compared to CON and BR sessions (p < .001), and no differences were found during the afternoon energy expenditure between conditions (BR: 1056.5 +/- 121.5; CON: 1185.7 +/- 173; EX: 996.1 +/- 153.4 Kcal). Total energy intake was significantly reduced on EX (p <.001). Dinner energy intake was significantly reduced during EX (491.65 +/- 75.74 Kcal) and CON (666.55 +/- 152.09 Kcal) compared with BR (818.87 +/- 122.97 Kcal) (p <.001). Appetite was not affected. Conclusion: Whereas intense exercise reduces daily energy balance in adolescents with obesity by mainly affecting ad libitum dinner energy consumption, imposed sedentary behaviors lead to increased energy intake and then positive energy balance. The impact of exercise or imposed sedentary behaviors on the energy balance of adolescents with obesity is not only related to the exercise-induced energy expenditure, but also to their energy intake