Effects of 2 different prior endurance exercises on whole-body fat oxidation kinetics: light vs. heavy exercise.

This study aimed to compare the effects of 2 different prior endurance exercises on subsequent whole-body fat oxidation kinetics. Fifteen men performed 2 identical submaximal incremental tests (Incr2) on a cycle ergometer after (i) a ∼40-min submaximal incremental test (Incr1) followed by a 90-min continuous exercise performed at 50% of maximal aerobic power-output and a 1-h rest period (Heavy); and (ii) Incr1 followed by a 2.5-h rest period (Light). Fat oxidation was measured using indirect calorimetry and plotted as a function of exercise intensity during Incr1 and Incr2. A sinusoidal equation, including 3 independent variables (dilatation, symmetry and translation), was used to characterize the fat oxidation kinetics and to determine the intensity (Fat(max)) that elicited the maximal fat oxidation (MFO) during Incr. After the Heavy and Light trials, Fat(max), MFO, and fat oxidation rates were significantly greater during Incr2 than Incr1 (p < 0.001). However, Δ (i.e., Incr2-Incr1) Fat(max), MFO, and fat oxidation rates were greater in the Heavy compared with the Light trial (p < 0.05). The fat oxidation kinetics during Incr2(Heavy) showed a greater dilatation and rightward asymmetry than Incr1(Heavy), whereas only a greater dilatation was observed in Incr2(Light) (p < 0.05). This study showed that although to a lesser extent in the Light trial, both prior exercise sessions led to an increase in Fat(max), MFO, and absolute fat oxidation rates during Incr2, inducing significant changes in the shape of the fat oxidation kinetics.

Comment diminuer son risque cardiovasculaire avec l'alimentation? Rôle des graisses consommées [Nutritional advice to help reduce the cardiovascular risk. Update of the Swiss Federal Office of Public Health's recommendations on fat consumption].

The Swiss Federal Office of Public Health's (FOPH) updated its recommendations on fat consumption in 2013. The report recommends that maximum 10% of the daily caloric intake should come from saturated fatty acids, and the total fat intake should account for 20-35%. There is no limitation to dietary cholesterol consumption. Recent studies have shown that replacing consumption of saturated fatty acids by unsaturated fatty acids is more beneficial in terms of cardiovascular prevention than a low fat diet. The purpose of this article is to review the FOPH recommendations on dietary fat as well as the current evidence about their cardiovascular benefit, and to provide a translation of these scientific recommendations into clinical advice.

Large differences in the prevalence of normal weight obesity using various cut-offs for excess body fat

BACKGROUND AND AIMS: Normal weight obesity (NWO) has been defined as an excessive body fat (BF) associated with a normal body mass index (BMI). Still, little is known regarding the effect of differing cut-offs for %BF on the prevalence of NWO. We thus conducted a study to assess the effect of modifying the cut-offs for excessive %BF on the prevalence of NWO. METHODS: We examined a convenience sample of 1523 Portuguese adults. BF was measured by validated hand-held bioimpedance. NWO was defined as a BMI < 25 kg/m2 and a %BF >30% or according to sex- and age-specific %BF cut-offs. RESULTS: Prevalence of NWO was 10.1% in women and 3.2% in men. In women, prevalence of NWO increased considerably with age, and virtually all women aged over 55 with a BMI < 25 kg/m2 were actually considered as NWO. Using sex-specific cut-offs for BF (men: 29.1%; women: 37.2%) led to moderately lower prevalence of NWO in women. Using sex and age-specific cut-offs for %BF considerably decreased the prevalence of NWO in women, i.e. 0.5e2.5% (depending on the criterion) but not in men, i.e. 1.9e3.4%. CONCLUSIONS: In women, the prevalence of NWO varies considerably according to the cut-off used to define excess BF, whereas a much smaller variation is found in men. While further studies are needed to describe the risk associated with NWO using various %BF cut-offs, this study suggests that sex- and age-specific cut-offs may be preferred.

Reference values of fat-free and fat masses by bioelectrical impedance analysis in 3393 healthy subjects.

Determination of fat-free mass (FFM) and fat mass (FM) is of considerable interest in the evaluation of nutritional status. In recent years, bioelectrical impedance analysis (BIA) has emerged as a simple, reproducible method used for the evaluation of FFM and FM, but the lack of reference values reduces its utility to evaluate nutritional status. The aim of this study was to determine reference values for FFM, FM, and %FM by BIA in a white population of healthy subjects, to observe the changes in these values with age, and to develop percentile distributions for these parameters. Whole-body resistance of 1838 healthy white men and 1555 women, aged 15-64 y, was determined by using four skin electrodes on the right hand and foot. FFM and FM were calculated according to formulas validated for the subject groups and analyzed for age decades. This is the first study to present BIA-determined age- and sex-specific percentiles for FFM, FM, and %FM for healthy subjects, aged 15-64 y. Mean FM and %FM increased progressively in men and after age 45 y in women. The results suggest that any weight gain noted with age is due to a gain in FM. In conclusion, the data presented as percentiles can serve as reference to evaluate the normality of body composition of healthy and ill subject groups at a given age.

Effect of hormone replacement therapy on vasomotor function of the coronary microcirculation in post-menopausal women with medically treated cardiovascular risk factors.

Aims The aim of this study was to evaluate the effect of hormone replacement therapy (HRT) on coronary vasomotor function in post-menopausal women (PM) with medically treated cardiovascular risk factors (RFs) in a cross-sectional and a longitudinal follow-up (FU) study. Methods and results Myocardial blood flow (MBF) response to cold pressor testing (CPT) and during pharmacologically induced hyperaemia was measured with positron emission tomography in pre-menopausal women (CON), in PM with HRT and without HRT, and repeated in PM after a mean FU of 24 +/- 14 months. When compared with CON at baseline, the endothelium-related change in MBF (DeltaMBF) to CPT progressively declined in PM with HRT and without HRT (0.35 +/- 0.23 vs. 0.24 +/- 0.20 and 0.16 +/- 0.12 mL/g/min; P = 0.171 and P = 0.021). In PM without HRT and in those with HRT at baseline but with discontinuation of HRT during FU, the endothelium-related DeltaMBF to CPT was significantly less at FU than at baseline (0.05 +/- 0.19 vs. 0.16 +/- 0.12 and -0.03 +/- 0.14 vs. 0.25 +/- 0.18 mL/g/min; P = 0.023 and P = 0.001), whereas no significant change was observed in PM with HRT (0.19 +/- 0.22 vs. 0.23 +/- 0.22 mL/g/min; P = 0.453). Impaired hyperaemic MBFs when compared with CON were not significantly altered from those at baseline exam. Conclusion Long-term administration of oestrogen may contribute to maintain endothelium-dependent coronary function in PM with medically treated cardiovascular RFs.

Impact of restrictive intravenous fluid replacement and combined epidural analgesia on perioperative volume balance and renal function within a Fast Track program.

BACKGROUND AND OBJECTIVE: Key factors of Fast Track (FT) programs are fluid restriction and epidural analgesia (EDA). We aimed to challenge the preconception that the combination of fluid restriction and EDA might induce hypotension and renal dysfunction. METHODS: A recent randomized trial (NCT00556790) showed reduced complications after colectomy in FT patients compared with standard care (SC). Patients with an effective EDA were compared with regard to hemodynamics and renal function. RESULTS: 61/76 FT patients and 59/75 patients in the SC group had an effective EDA. Both groups were comparable regarding demographics and surgery-related characteristics. FT patients received significantly less i.v. fluids intraoperatively (1900 mL [range 1100-4100] versus 2900 mL [1600-5900], P < 0.0001) and postoperatively (700 mL [400-1500] versus 2300 mL [1800-3800], P < 0.0001). Intraoperatively, 30 FT compared with 19 SC patients needed colloids or vasopressors, but this was statistically not significant (P = 0.066). Postoperative requirements were low in both groups (3 versus 5 patients; P = 0.487). Pre- and postoperative values for creatinine, hematocrit, sodium, and potassium were similar, and no patient developed renal dysfunction in either group. Only one of 82 patients having an EDA without a bladder catheter had urinary retention. Overall, FT patients had fewer postoperative complications (6 versus 20 patients; P = 0.002) and a shorter median hospital stay (5 [2-30] versus 9 d [6-30]; P< 0.0001) compared with the SC group. CONCLUSIONS: Fluid restriction and EDA in FT programs are not associated with clinically relevant hemodynamic instability or renal dysfunction.

Different transcriptional control of metabolism and extracellular matrix in visceral and subcutaneous fat of obese and rimonabant treated mice.

BACKGROUND: The visceral (VAT) and subcutaneous (SCAT) adipose tissues play different roles in physiology and obesity. The molecular mechanisms underlying their expansion in obesity and following body weight reduction are poorly defined. METHODOLOGY: C57Bl/6 mice fed a high fat diet (HFD) for 6 months developed low, medium, or high body weight as compared to normal chow fed mice. Mice from each groups were then treated with the cannabinoid receptor 1 antagonist rimonabant or vehicle for 24 days to normalize their body weight. Transcriptomic data for visceral and subcutaneous adipose tissues from each group of mice were obtained and analyzed to identify: i) genes regulated by HFD irrespective of body weight, ii) genes whose expression correlated with body weight, iii) the biological processes activated in each tissue using gene set enrichment analysis (GSEA), iv) the transcriptional programs affected by rimonabant. PRINCIPAL FINDINGS: In VAT, "metabolic" genes encoding enzymes for lipid and steroid biosynthesis and glucose catabolism were down-regulated irrespective of body weight whereas "structure" genes controlling cell architecture and tissue remodeling had expression levels correlated with body weight. In SCAT, the identified "metabolic" and "structure" genes were mostly different from those identified in VAT and were regulated irrespective of body weight. GSEA indicated active adipogenesis in both tissues but a more prominent involvement of tissue stroma in VAT than in SCAT. Rimonabant treatment normalized most gene expression but further reduced oxidative phosphorylation gene expression in SCAT but not in VAT. CONCLUSION: VAT and SCAT show strikingly different gene expression programs in response to high fat diet and rimonabant treatment. Our results may lead to identification of therapeutic targets acting on specific fat depots to control obesity.

Beneficial effects of combinatorial micronutrition on body fat and atherosclerosis in mice.

AIMS: More than two billion people worldwide are deficient in key micronutrients. Single micronutrients have been used at high doses to prevent and treat dietary insufficiencies. Yet the impact of combinations of micronutrients in small doses aiming to improve lipid disorders and the corresponding metabolic pathways remains incompletely understood. Thus, we investigated whether a combination of micronutrients would reduce fat accumulation and atherosclerosis in mice. METHODS AND RESULTS: Lipoprotein receptor-null mice fed with an original combination of micronutrients incorporated into the daily chow showed reduced weight gain, body fat, plasma triglycerides, and increased oxygen consumption. These effects were achieved through enhanced lipid utilization and reduced lipid accumulation in metabolic organs and were mediated, in part, by the nuclear receptor PPARα. Moreover, the micronutrients partially prevented atherogenesis when administered early in life to apolipoprotein E-null mice. When the micronutrient treatment was started before conception, the anti-atherosclerotic effect was stronger in the progeny. This finding correlated with decreased post-prandial triglyceridaemia and vascular inflammation, two major atherogenic factors. CONCLUSION: Our data indicate beneficial effects of a combination of micronutritients on body weight gain, hypertriglyceridaemia, liver steatosis, and atherosclerosis in mice, and thus our findings suggest a novel cost-effective combinatorial micronutrient-based strategy worthy of being tested in humans.

Role of fat oxidation in the long-term stabilization of body weight in obese women.

Two studies were performed to investigate the association between body fat mass and fat oxidation. The first, a cross-sectional study of 106 obese women maintaining stable body weight, showed that these two variables were significantly correlated (r = 0.56, P less than 0.001) and the regression coefficient indicated that a 10-kg change in fat mass corresponded to a change in fat oxidation of approximately 20 g/d. The second, a prospective study, validated this estimate and quantifies the long-term adaptations in fat oxidation resulting from body fat loss. Twenty-four moderately obese women were studied under controlled dietary conditions at stable weight before and after mean weight and fat losses of 12.7 and 9.8 kg, respectively. The reduction in fat oxidation was identical to that predicted by the above regression. We conclude that changes in fat mass significantly affect fat oxidation and that this process may contribute to the long-term regulation of fat and energy balance in obese individuals.

Prevention and management of potential adverse events during transapical aortic valve replacement.

BACKGROUND AND AIM OF THE STUDY: Transapical transcatheter aortic valve replacement (TAVR) is a new minimally invasive technique with a known risk of unexpected intra-procedural complications. Nevertheless, the clinical results are good and the limited amount of procedural adverse events confirms the usefulness of a synergistic surgical/anesthesiological management in case of unexpected emergencies. METHODS: A review was made of the authors' four-year database and other available literature to identify major and minor intra-procedural complications occurring during transapical TAVR procedures. All implants were performed under general anesthesia with a balloon-expandable Edwards Sapien stent-valve, and followed international guidelines on indications and techniques. RESULTS: Procedural success rates ranged between 94% and 100%. Life-threatening apical bleeding occurred very rarely (0-5%), and its incidence decreased after the first series of implants. Stent-valve embolization was also rare, with a global incidence ranging from 0-2%, with evidence of improvement after the learning curve. Rates of valve malpositioning ranged from 0% to < 3%, whereas the risk of coronary obstruction ranged from 0% to 3.5%. Aortic root rupture and dissection were dramatic events reported in 0-2% of transapical cases. Stent-valve malfunction was rarely reported (1-2%), whereas the valve-in-valve bailout procedure for malpositioning, malfunctioning or severe paravalvular leak was reported in about 1.0-3.5% of cases. Sudden hemodynamic management and bailout procedures such as valve-in-valve rescue or cannulation for cardiopulmonary bypass were more effective when planned during the preoperative phase. CONCLUSION: Despite attempts to avoid pitfalls, complications during transapical aortic valve procedures still occur. Preoperative strategic planning, including hemodynamic status management, alternative cannulation sites and bailout procedures, are highly recommended, particularly during the learning curve of this technique.

Fructose and metabolic diseases: new findings, new questions.

There has been much concern regarding the role of dietary fructose in the development of metabolic diseases. This concern arises from the continuous increase in fructose (and total added caloric sweeteners consumption) in recent decades, and from the increased use of high-fructose corn syrup (HFCS) as a sweetener. A large body of evidence shows that a high-fructose diet leads to the development of obesity, diabetes, and dyslipidemia in rodents. In humans, fructose has long been known to increase plasma triglyceride concentrations. In addition, when ingested in large amounts as part of a hypercaloric diet, it can cause hepatic insulin resistance, increased total and visceral fat mass, and accumulation of ectopic fat in the liver and skeletal muscle. These early effects may be instrumental in causing, in the long run, the development of the metabolic syndrome. There is however only limited evidence that fructose per se, when consumed in moderate amounts, has deleterious effects. Several effects of a high-fructose diet in humans can be observed with high-fat or high-glucose diets as well, suggesting that an excess caloric intake may be the main factor involved in the development of the metabolic syndrome. The major source of fructose in our diet is with sweetened beverages (and with other products in which caloric sweeteners have been added). The progressive replacement of sucrose by HFCS is however unlikely to be directly involved in the epidemy of metabolic disease, because HFCS appears to have basically the same metabolic effects as sucrose. Consumption of sweetened beverages is however clearly associated with excess calorie intake, and an increased risk of diabetes and cardiovascular diseases through an increase in body weight. This has led to the recommendation to limit the daily intake of sugar calories.

Clinical relevance of L-carnitine-supplemented total parenteral nutrition in postoperative trauma. Metabolic effects of continuous or acute carnitine administration with special reference to fat oxidation and nitrogen utilization.

Carnitine-free total parenteral nutrition (TPN) is claimed to result in a carnitine deficiency with subsequent impairment of fat oxidation. The present study was designed to evaluate the possible benefit of carnitine supplementation on postoperative fat and nitrogen utilization. Sixteen patients undergoing total esophagectomy were evenly randomized and received TPN without or with L-carnitine supplementation (74 mumol.kg-1.d-1) during 11 postoperative days. On day 11, a 4-h infusion of L-carnitine (125 mumol/kg) was performed in both groups. The effect of supplementation was evaluated by indirect calorimetry, N balance, and repeated measurements of plasma lipids and ketone bodies. Irrespective of continuous or acute supplementation, respiratory quotient and fat oxidation were similarly maintained throughout the study in both groups whereas N balance appeared to be more favorable without carnitine. We conclude that carnitine-supplemented TPN does not improve fat oxidation or promote N utilization in the postoperative phase.

Size and fat content of gynes in relation to the mode of colony founding in ants (Hymenoptera; Formicidae)

In ants, there are two main processes of colony founding, the independent and the dependent modes. In the first case young queens start colony founding without the help of workers, whereas in the second case they are accompanied by workers. To determine the relation between the mode of colony founding and the physiology of queens, we collected mature gynes of 24 ant species. Mature gynes of species utilizing independent colony founding had a far higher relative fat content than gynes of species employing dependent colony founding. These fat reserves are stored during the period of maturation, i.e. between the time of emergence and mating, and serve as fuel during the time of colony founding to nurture the queen and the brood. Gynes of species founding independently but non claustrally were found to have a relative fat content intermediate between the values found for gynes founding independently and those founding dependently. This suggests that such gynes rely partially on their fat reserves and partially on the energy provided by prey they collect to nurture themselves and the first brood during the time of colony founding. Study of the fat content of mature gynes of all species has shown that it gives a good indication of the mode of colony founding.

Cross-sectional analysis of testosterone therapies in hypopituitary men on stable pituitary hormone replacement.

OBJECTIVE: The last decade has seen a proliferation in options for testosterone replacement. However, little is known as to the benefits of different treatment modalities. Our objective was to determine the testosterone prescription pattern and to examine the impact on various outcome measures. SUBJECTS AND METHODS: A total of 816 adult-onset hypopituitary males on stable pituitary replacement for at least 1 year were identified from the KIMS database. Patients were classified as either eugonadal (n = 106), or hypogonadal (n = 710) on intramuscular (IM, n = 558), oral (n = 74), transdermal (n = 61), and depot (n = 17) testosterone. RESULTS: After 1 year of stable pituitary replacement therapy, body composition, cardiovascular parameters, GH replacement and quality of life were not significantly different in androgen-replaced hypogonadal patients compared to eugonadal patients. There were no differences in outcome variables within the hypogonadal group according to the testosterone replacement regimen used and no difference in response to GH therapy. CONCLUSIONS: The majority of hypopituitary patients in the last decade have received IM testosterone. Body composition, cardiovascular parameters, GH replacement and quality of life were not different between eugonadal and hypogonadal patients and were not differentially affected by the mode of testosterone replacement. These findings are reassuring that there is no major difference in response to different testosterone replacement regimens.