Selective reduction in body fat mass and plasma leptin induced by angiotensin-converting enzyme inhibition in rats

Objective: There is emerging evidence that angiotensin stimulates adipocyte differentiation and lipogenesis. This study tested the hypothesis that inhibition of angiotensin II by treatment with an angiotensin-converting enzyme inhibitor, perindopril, would reduce fat mass in rats. Design: After a 12-day baseline, rats were divided into two groups: one was untreated and the other received perindopril (1.2 mg kg⁻¹ per day) in drinking water for 26 days.Subjects: In total, 16 male Sprague–Dawley rats aged 10 weeks at the start of the study. Measurements: Plasma leptin was measured in samples collected at baseline, half-way through and at the end of treatment. Body weight, food and water intake were measured daily throughout the experiment. Body fat mass, bone and lean mass were determined by dual energy X-ray absorptiometry (DEXA) at the end of the treatment period. Results: Daily food intake was the same in both groups throughout the study. By the end of treatment, animals receiving perindopril showed a modest reduction in weight gain relative to the untreated animals (62.4±5.0 g vs 73.0±4.0 g; P<0.05). DEXA analysis showed that body composition was greatly altered and the perindopril-treated group had 26% less body fat mass than the untreated group (61.0±5.2 g vs 44.4±4.2 g; P<0.01). The reduction in body fat mass was correlated with reductions in the weight of both the epididymal and retroperitoneal fat pads (P<0.001). Similarly, plasma leptin was reduced by perindopril treatment (4.64±0.56 ng ml⁻¹) compared to the untreated group (8.27±1.03 ng ml⁻¹; P<0.001). In contrast, there were no differences in lean or bone mass between the two groups.Conclusion: Oral treatment with perindopril selectively reduced body fat mass without influencing daily food intake. In contrast, there were no differences in lean or bone mass between the two groups

Field metabolic rate and body water turnover of the red fox (Vulpes vulpes) in Australia

We measured the daily energy expenditure of free-living red foxes Vulpes vulpes occupying a temperate region of New South Wales, Australia. Field metabolic rate (FMR) and body water turnover were estimated using doubly labelled water. In autumn, male body mass ranged from 5 to 6.1 kg (mean 5.6 kg) and their FMRs averaged 2328 kJ/day. Female body mass in autumn ranged from 4.9 to 6.6 kg (mean 5.4 kg) and their FMRs averaged 1681 kJ/day. Body water influx for males and females was 314 and 251 mL/day, respectively. Body composition of each fox was analysed after the field measurements and revealed a significant correlation between body water content, as estimated from tritiated water space, and body lipids (r² = 0.72). This supports the use of body water determination as a potentially non-destructive method to gauge body condition.

Bipolar disorder and adiposity : a study using whole body dual energy X-ray absorptiometry scans

Objective: Previous research has demonstrated a relationship between adiposity and bipolar disorder, although data are derived predominantly from patient samples and use indirect methods of assessing adiposity. This study investigated the association between bipolar disorder and several indices of adiposity, including body fat mass as measured by dual energy X-ray absorptiometry (DXA), in a community-based sample.

Methods: In this study, 21 women with bipolar disorder and 523 healthy controls were drawn from an age-stratified, random, community-based sample of women (20–93 years) participating in the Geelong Osteoporosis Study. Bipolar disorder was diagnosed utilising a semi-structured clinical interview. Anthropometric measurements (weight, height, waist and hip circumference) were taken and fat mass was determined from whole body DXA scans (Lunar DPX-L).

Results: Those with bipolar disorder tended to have greater adiposity. Age-adjusted mean (95% CI) values for bipolar versus controls according to adiposity indices were weight 75.6 (68.9–82.3) versus 72.6 (71.3–74.0) kg, waist circumference 89.8 (84.1–95.6) versus 87.3 (86.1–88.5) cm, waist:hip ratio 0.85 (0.82–0.87) versus 0.84 (0.83–0.84), body mass index 27.6 (25.1–30.1) versus 27.5 (27.0–28.0) kg/m2, fat mass 31.4 (26.5–36.3) versus 28.6 (27.5–29.5) kg and %body fat 40.4 (36.9–43.9) versus 38.0 (37.3–38.7)%; all p > 0.05. Further adjustment for height, smoking, alcohol, psychotropic medication, energy intake or physical activity did not influence these patterns.

Conclusion: Although a pattern suggestive of greater adiposity among those with bipolar disorder was observed, no significant differences were detected. We cannot exclude the possibility of a type II error. Further research with a larger sample may produce more conclusive results.

Prevalence of obesity and the relationship between the body mass index and body fat : cross-sectional, population-based data

Background: Anthropometric measures such as the body mass index (BMI) and waist circumference are widely used as convenient indices of adiposity, yet there are limitations in their estimates of body fat. We aimed to determine the prevalence of obesity using criteria based on the BMI and waist circumference, and to examine the relationship between the BMI and body fat.

Methodology/Principal Findings: This population-based, cross-sectional study was conducted as part of the Geelong Osteoporosis Study. A random sample of 1,467 men and 1,076 women aged 20–96 years was assessed 2001–2008. Overweight and obesity were identified according to BMI (overweight 25.0–29.9 kg/m2; obesity $30.0 kg/m2) and waist circumference (overweight men 94.0–101.9 cm; women 80.0–87.9 cm; obesity men $102.0 cm, women $88.0 cm); body fat mass was assessed using dual energy X-ray absorptiometry; height and weight were measured and lifestyle factors documented by self-report. According to the BMI, 45.1% (95%CI 42.4–47.9) of men and 30.2% (95%CI 27.4–33.0) of women were overweight and a further 20.2% (95%CI 18.0–22.4) of men and 28.6% (95%CI 25.8–31.3) of women were obese. Using waist circumference, 27.5% (95%CI 25.1–30.0) of men and 23.3% (95%CI 20.8–25.9) of women were overweight, and 29.3% (95%CI 26.9–31.7) of men and 44.1% (95%CI 41.2–47.1) of women, obese. Both criteria indicate that approximately 60% of the population exceeded recommended thresholds for healthy body habitus. There was no consistent pattern apparent between BMI and energy intake. Compared with women, BMI overestimated adiposity in men, whose excess weight was largely attributable to muscular body builds and greater bone mass. BMI also underestimated adiposity in the elderly. Regression models including gender, age and BMI explained 0.825 of the variance in percent body fat.

Conclusions/Significance: As the BMI does not account for differences in body composition, we suggest that gender- and age-specific thresholds should be considered when the BMI is used to indicate adiposity.

Does agricultural food provide a good alternative to a natural diet for body store deposition in geese?

Over the past decades most goose populations have become increasingly dependent on agricultural crops during wintering and migration periods. The suitability of agricultural crops to support all nutritional requirements of migratory geese for the deposition of body stores has been questioned; feeding on agricultural crops may yield higher rates of fat deposition at the cost of reduced protein accretion due to an unbalanced diet. We compared amino-acid composition of forage, and investigated food-habitat use and dynamics and composition of body stores deposited by barnacle geese feeding on agricultural pasture and in natural salt marsh during spring migratory preparation. Overall content and composition of amino acids was similar among forage from both habitats and appeared equally suitable for protein accretion. There was no relationship between body composition of geese and their preferred food habitat. Fat and wet protein contributed with 67% and 33%, respectively, to body stores gained at a rate of 11 g/d throughout the one-month study period. We found no evidence of impaired protein accretion in geese using agricultural grassland compared to natural salt marsh. Our study supports the hypothesis that the expansion of feeding habitat by including agricultural grassland has played an important role in the recent growth of the East Atlantic flyway population of barnacle geese and other herbivorous waterbirds. Feeding refuges of improved grassland provide geese with an adequate diet for the deposition of body stores crucial for spring migration and subsequent reproduction, thereby alleviating the conflict with agriculture.

Musculoskeletal deterioration in men accompanies increases in body fat

Objective
To examine body fat and musculoskeletal changes in men over 5 years.

Methods
Body composition was evaluated for men in the Geelong Osteoporosis Study using whole body dual energy X-ray absorptiometry (DXA) during two time-periods. DXA was performed for 1329 men (25-96 years) during 2001-2006 and for 900 men (25-98 years), 2006-2011. The masses of fat, lean, and bone were expressed relative to the square of height (kg/m2). Each compartment was also expressed as a percentage relative to body weight (%fat, %lean, %bone).

Results
Mean BMI increased from 26.9 kg/m2 in 2001-2006, to 27.2 kg/m2 in 2006-2011 (P = 0.04). Mean fat mass increased by 9.0% from 6.98 kg/m2 (95%CI 6.84-7.11) in 2001-2006, to 7.60 kg/m2 (7.44-7.77) in 2006-2011 (P < 0.001); mean lean mass decreased by 0.9%, from 18.92 kg/m2 (18.83-19.01) to 18.75 kg/m2 (18.64-18.86) (P = 0.02), and mean bone mass decreased 1.6% from 1.041 kg/m2 (1.034-1.047), to 1.024 kg/m2 (1.016-1.032). Mean %fat increased from 23.4% to 25.2%, mean %lean decreased from 72.6% to 70.9% and mean %bone decreased from 4.0% to 3.9% (all P < 0.05).

Conclusions
An increase in BMI, which reflects a substantial increase in body fat mass and declines in both lean and bone mass was reported. This may have implications for future development of bone fragility, sarcopenia, and sarcopenic obesity.

IUGR in the absence of postnatal 'catch-up' growth leads to improved whole body insulin sensitivity in rat offspring

A suboptimal in utero environment leads to fetal adaptations to ensure short-term survival but in the long-term may lead to disease when the postnatal growth does not reflect that in utero. This study examined the effect of IUGR on whole body insulin sensitivity and metabolic activity in adult rats. Female Wistar-Kyoto rats were fed either a normal protein diet (NPD 20% casein) or a low protein diet (LPD; 8.7% casein) during pregnancy and 2 wk of lactation. In offspring at 32 wk of age, indirect calorimetry and dual energy x-ray absorptiometry (DEXA) were performed to assess metabolic activity and body composition. Insulin sensitivity was assessed using a euglycemic-hyperinsulinemic clamp. At 3 d of age, male and female LPD offspring were 23 and 27% smaller than controls, respectively. They remained significantly smaller throughout the experimental period (~10% smaller at 32 wk). Importantly, there was increased insulin sensitivity in LPD offspring (47% increase in males and 38% increase in females); pancreatic insulin content was normal. Body composition, O2 consumption, respiratory exchange ratio (RER), and locomotor activity were not different to controls. These findings suggest that in the absence of “catch-up” growth IUGR programs for improved insulin sensitivity.

Sexual size dimorphism and body condition in the Australasian Gannet

Sexual size dimorphism is widespread throughout seabird taxa and several drivers leading to its evolution have been hypothesised. While the Australasian Gannet (Morus serrator) has previously been considered nominally monomorphic, recent studies have documented sexual segregation in diet and foraging areas, traits often associated with size dimorphism. The present study investigated the sex differences in body mass and structural size of this species at two colonies (Pope's Eye, PE; Point Danger, PD) in northern Bass Strait, south-eastern Australia. Females were found to be 3.1% and 7.3% heavier (2.74 ± 0.03, n = 92; 2.67 ± 0.03 kg, n = 43) than males (2.66 ± 0.03, n = 92; 2.48 ± 0.03 kg, n = 43) at PE and PD, respectively. Females were also larger in wing ulna length (0.8% both colonies) but smaller in bill depth (PE: 2.2%; PD: 1.7%) than males. Despite this dimorphism, a discriminant function provided only mild accuracy in determining sex. A similar degree of dimorphism was also found within breeding pairs, however assortative mating was not apparent at either colony (R2 < 0.04). Using hydrogen isotope dilution, a body condition index was developed from morphometrics to estimate total body fat (TBF) stores, where TBF(%) = 24.43+1.94*(body mass/wing ulna length) - 0.58*tarsus length (r2 = 0.84, n = 15). This index was used to estimate body composition in all sampled individuals. There was no significant difference in TBF(%) between the sexes for any stage of breeding or in any year of the study at either colony suggesting that, despite a greater body mass, females were not in a better condition than males. While the driving mechanism for sexual dimorphism in this species is currently unknown, studies of other Sulids indicate segregation in foraging behaviour, habitat and diet may be a contributing factor.

Changing guards: time to move beyond body mass index for population monitoring of excess adiposity

With the obesity epidemic, and the effects of aging populations, human phenotypes have changed over two generations, possibly more dramatically than in other species previously. As obesity is an important and growing hazard for population health, we recommend a systematic evaluation of the optimal measure(s) for population-level excess body fat. Ideal measure(s) for monitoring body composition and obesity should be simple, as accurate and sensitive as possible, and provide good categorization of related health risks. Combinations of anthropometric markers or predictive equations may facilitate better use of anthropometric data than single measures to estimate body composition for populations. Here, we provide new evidence that increasing proportions of aging populations are at high health-risk according to waist circumference, but not body mass index (BMI), so continued use of BMI as the principal population-level measure substantially underestimates the health-burden from excess adiposity.

Exploring the dietary patterns of young New Zealand women and associations with BMI and body fat

Examining dietary patterns provides an alternative approach to investigating dietary behaviors related to excess adiposity. The study aim was to investigate dietary patterns and body composition profiles of New Zealand European (NZE) women, participating in the women’s EXPLORE (Examining the Predictors Linking Obesity Related Elements) study. Post-menarche, pre-menopausal NZE women (16-45 years) (n = 231) completed a validated 220-item, self-administrated, semi-quantitative food frequency questionnaire. Body mass index (BMI) was calculated using measured height (cm) and weight (kg); body fat percentage (BF%) was measured using air displacement plethysmography (BodPod). Dietary patterns were identified using principal component factor analysis. Associations between dietary patterns, age, BMI and BF% were investigated. Four dietary patterns were identified: snacking; energy-dense meat; fruit and vegetable; healthy, which explained 6.9%, 6.8%, 5.6% and 4.8% of food intake variation, respectively. Age (p = 0.012) and BMI (p = 0.016) were positively associated with the “energy-dense meat” pattern. BF% (p = 0.016) was positively associated with the “energy-dense meat” pattern after adjusting for energy intake. The women following the identified dietary patterns had carbohydrate intakes below and saturated fat intakes above recommended guidelines. Dietary patterns in NZE women explain only some variations in body composition. Further research should examine other potential factors including physical activity and socioeconomic status.

Genetic variation and obesity in Australian women: A prospective study.

Objective: A number of candidate genes have been implicated in the pathogenesis of obesity in humans. This study examines associations between longitudinal changes in body mass and composition and the presence of polymorphisms in the ß-3 adrenergic receptor, tumor necrosis factor-α, leptin, and leptin receptor (Lepr) in a cohort of Australian women.

Research Methods and Procedures: Healthy white Australian women (n = 335) were randomly selected from the Barwon region of Victoria and underwent baseline anthropometry and double-energy X-ray absorptiometry for assessment of body mass and adiposity. These measurements were repeated again at 2-year follow-up. Genomic DNA was extracted and used for polymerase chain reaction-based genotyping of all polymorphisms.

Results: The Pro1019Pro Lepr polymorphism was associated with longitudinal increases in body weight (p = 0.02), fat mass (p = 0.05), and body mass index (p = 0.01) in this study, and individuals homozygous for the A allele at this locus had a greater propensity to gain body fat over time. The largest effects on body composition seemed to be in individuals already obese at baseline. Changes in body weight, fat mass, percent body fat, and body mass index over a 2-year period were not associated with genetic variation in the ß-3 adrenergic receptor (Trp64Arg), tumor necrosis factor-α promoter, or leptin genes in non-obese or obese women.

Discussion: These results suggest that a Lepr polymorphism is involved in the regulation of body mass and adiposity in obese Australian white women, which may have implications for the treatment of obesity in this population.

Does high-intensity resistance training maintain bone mass during moderate weight loss in older overweight adults with type 2 diabetes?

The aim was to investigate whether the addition of supervised high intensity progressive resistance training to a moderate weight loss program (RT+WLoss) could maintain bone mineral density (BMD) and lean mass compared to moderate weight loss (WLoss) alone in older overweight adults with type 2 diabetes. We also investigated whether any benefits derived from a supervised RT program could be sustained through an additional home-based program. This was a 12-month trial in which 36 sedentary, overweight adults aged 60 to 80 years with type 2 diabetes were randomized to either a supervised gymnasium-based RT+WLoss or WLoss program for 6 months (phase 1). Thereafter, all participants completed an additional 6-month home-based training without further dietary modification (phase 2). Total body and regional BMD and bone mineral content (BMC), fat mass (FM) and lean mass (LM) were assessed by DXA every 6 months. Diet, muscle strength (1-RM) and serum total testosterone, estradiol, SHBG, insulin and IGF-1 were measured every 3 months. No between group differences were detected for changes in any of the hormonal parameters at any measurement point. In phase 1, after 6 months of gymnasium-based training, weight and FM decreased similarly in both groups (P<0.01), but LM tended to increase in the RT+WLoss (n=16) relative to the WLoss (n=13) group [net difference (95% CI), 1.8% (0.2, 3.5), P<0.05]. Total body BMD and BMC remained unchanged in the RT+WLoss group, but decreased by 0.9 and 1.5%, respectively, in the WLoss group (interaction, P<0.05). Similar, though non-significant, changes were detected at the femoral neck and lumbar spine (L2-L4). In phase 2, after a further 6 months of home-based training, weight and FM increased significantly in both the RT+WLoss (n=14) and WLoss (n=12) group, but there were no significant changes in LM or total body or regional BMD or BMC in either group from 6 to 12 months. These results indicate that in older, overweight adults with type 2 diabetes, dietary modification should be combined with progressive resistance training to optimize the effects on body composition without having a negative effect on bone health.

Genetic albation of the c-Cbl ubiquitin ligase domain results in increased energy expenditure and improved insulin action

Casitas b-lineage lymphoma (c-Cbl) is a multiadaptor protein with E3-ubiquitin ligase activity residing within its RING finger domain. We have previously reported that c-Cbl–deficient mice exhibit elevated energy expenditure, reduced adiposity, and improved insulin action. In this study, we examined mice expressing c-Cbl protein with a loss-of-function mutation within the RING finger domain (c-Cbl^A/– mice). Compared with control animals, c-Cbl^A/– mice display a phenotype that includes reduced adiposity, despite greater food intake; reduced circulating insulin, leptin, and triglyceride levels; and improved glucose tolerance. c-Cbl^A/– mice also display elevated oxygen consumption (13%) and are protected against high-fat diet–induced obesity and insulin resistance. Unlike c-Cbl^A/– mice, mice expressing a mutant c-Cbl with the phosphatidylinositol (PI) 3-kinase binding domain ablated (c-Cbl^F/F mice) exhibited an insulin sensitivity, body composition, and energy expenditure similar to that of wild-type animals. These results indicate that c-Cbl ubiquitin ligase activity, but not c-Cbl–dependent activation of PI 3-kinase, plays a key role in the regulation of whole-body energy metabolism.

The comparative energetics and growth strategies of sympatric Antarctic and subantarctic fur seal pups at Iles Crozet

The period of maternal dependence is a time during which mammalian infants must optimise both their growth and the development of behavioural skills in order to successfully meet the demands of independent living. The rate and duration of maternal provisioning, post-weaning food availability and climatic conditions are all factors likely to influence the growth strategies of infants. While numerous studies have documented differences in growth strategies at high taxonomic levels, few have investigated those of closely related species inhabiting similar environments. The present study examined the body composition, metabolism and indices of physiological development in pups of Antarctic fur seals (Arctocephalus gazella) and subantarctic fur seals (Arctocephalus tropicalis), congeneric species with different weaning ages (4 months and 10 months, respectively), during their overlap in lactation at a sympatric breeding site in the Iles Crozet. Body lipid reserves in pre-moult pups were significantly greater (t₂₈=2.73, P<0.01) in subantarctic (26%) than Antarctic fur seals (22%). Antarctic fur seal pups, however, had significantly higher (t₂₆=3.82, P<0.001) in-air resting metabolic rates (RMR; 17.1±0.6 ml O₂ kg^-1 min^-1) than subantarctic fur seal pups (14.1±0.5 ml O2 kg^-1 min^-1). While in-water standard metabolic rate (SMR; 22.9±2.5 ml O2 kg^-1 min^-1) was greater than in-air RMR for Antarctic fur seal pups (t₉=2.59, P<0.03), there were no significant differences between in-air RMR and in-water SMR for subantarctic fur seal pups (t₁₂=0.82, P>0.4), although this is unlikely to reflect a greater ability for pre-moult pups of the latter species to thermoregulate in water. Pup daily energy expenditure was also significantly greater (t₂₇=2.36, P<0.03) in Antarctic fur seals (638±33 kJ kg^-1 day^-1) than in subantarctic fur seals (533±33 kJ kg^-1 day^-1), which corroborates observations that pups of the former species spend considerably more time actively learning to swim and dive. Consistent with this observation is the finding that blood oxygen storage capacity was significantly greater (t₉=2.81, P<0.03) in Antarctic (11.5%) than subantarctic fur seal (8.9%) pups. These results suggest that, compared with subantarctic fur seals, Antarctic fur seal pups adopt a strategy of faster lean growth and physiological development, coupled with greater amounts of metabolically expensive behavioural activity, in order to acquire the necessary foraging skills in time for their younger weaning age.