Food Restriction Engages Prefrontal Corticostriatal Cells and Local Microcircuitry to Drive the Decision to Run versus Conserve Energy.

Food restriction (FR) evokes running, which may promote adaptive foraging in times of food scarcity, but can become lethal if energy expenditure exceeds caloric availability. Here, we demonstrate that chemogenetic activation of either the general medial prefrontal cortex (mPFC) pyramidal cell population, or the subpopulation projecting to dorsal striatum (DS) drives running specifically during hours preceding limited food availability, and not during ad libitum food availability. Conversely, suppression of mPFC pyramidal cells generally, or targeting mPFC-to-DS cells, reduced wheel running specifically during FR and not during ad libitum food access. Post mortem c-Fos analysis and electron microscopy of mPFC layer 5 revealed distinguishing characteristics of mPFC-to-DS cells, when compared to neighboring non-DS-projecting pyramidal cells: 1) greater recruitment of GABAergic activity and 2) less axo-somatic GABAergic innervation. Together, these attributes position the mPFC-to-DS subset of pyramidal cells to dominate mPFC excitatory outflow, particularly during FR, revealing a specific and causal role for mPFC-to-DS control of the decision to run during food scarcity. Individual differences in GABAergic activity correlate with running response to further support this interpretation. FR enhancement of PFC-to-DS activity may influence neural circuits both in studies using FR to motivate animal behavior and in human conditions hallmarked by FR.

Cardioprotection by triiodothyronine following caloric restriction via long noncoding RNAs.

Severe caloric-restriction compromises thyroid hormone (TH) status, apparently to save energy and proteins for enduring stress stimulus. However, a persistent decrease in TH levels may compromise heart function. We hypothesized that supplementation of low dose active TH or targeting hypoxia-inducible factor-1-alpha, HIF-1α (a strong activator of deiodinase enzyme that degrades peripheral active THs) will prevent deterioration of cardiac performance. Adult mice were subjected to acute fasting based on institutional animal protocols with ad libitum access to water. The following groups were studied: Control mice with free access to food; severe caloric restriction fasting only group; Fasting with Triiodo-l-Thyronine (T3); Fasting with HIF-1α inhibitor (BAY). Cardiac hemodynamic and electrophysiological studies were performed and role of long noncoding RNAs were explored. Following severe caloric-restriction, we found that body weights, and heart weights to a partial extent, were decreased. Low-dose T3 treatment attenuated left ventricular hemodynamic impairment in indices of cardiac contractility and relaxation. In electrophysiology studies, fasting mice developed atrial tachyarrhythmias upon induction. This reverted to control levels following T3 treatment. There was a significant increase in atrioventricular conduction time and significant decrease in heart rate following fasting. Both these changes were attenuated following T3 treatment. Furthermore, BAY partially improved hemodynamics. Compared to the severe caloric-restriction group, both T3 and BAY reduced MALAT1 and GAS5 long noncoding RNA expression. These new findings indicate that T3 and BAY protect from cardiac decompensation secondary to acute severe caloric-restriction partly mediated by long noncoding RNAs.

Effects of whole-body electromyostimulation exercise and caloric restriction on cardiometabolic risk profile and muscle strength in obese women with the metabolic syndrome: a pilot study.

Obesity, particularly in conjunction with further cardiometabolic risk factors, is associated with an increased risk of cardiovascular disease and mortality. Increased physical activity and dietary modifications are cornerstones of therapeutic interventions to treat obesity and related risk factors. Whole-body electromyostimulation (WB-EMS) has emerged as an innovative, time-efficient type of exercise that can provide positive effects on body composition and muscle strength. However, the impact of WB-EMS on cardiometabolic health in obese individuals with metabolic syndrome (MetS) has yet to be determined. The aim of this pilot study was, therefore, to investigate the feasibility and effects of WB-EMS on cardiometabolic risk markers and muscle strength in obese women diagnosed with MetS. Twenty-nine obese women (56.0 ± 10.9 years, BMI: 36.7 ± 4.6 kg/m2) with the clinical diagnosis of MetS were randomized to either 12 weeks of WB-EMS (n = 15) or an inactive control group (CON, n = 14). Both groups received nutritional counseling (aim: -500 kcal energy deficit/day). WB-EMS was performed 2x/week (20 min/session). Body composition, maximum strength (Fmax) of major muscle groups, selected cardiometabolic risk indices and the metabolic syndrome Z-score (MetS-Z) were determined baseline and after the intervention. WB-EMS was well tolerated and no adverse events occurred. Body weight was significantly reduced in both groups by an average of ~3 kg (P < 0.01). The body fat percentage was only decreased in the WB-EMS group (P = 0.018). Total cholesterol concentrations decreased in the WB-EMS group (P = 0.018) and in CON (P = 0.027). Only the WB-EMS group increased Fmax significantly in all major muscle groups (P < 0.05) and improved the overall cardiometabolic risk score (MetS-Z, P = 0.029). This pilot study indicates that WB-EMS can be considered as a feasible and time-efficient exercise option for improving body composition, muscle strength and cardiometabolic health in obese women with MetS. Moreover, these findings underpin the crucial role of exercise during weight loss interventions in improving health outcomes.

Moderate differences in common feeding diets change lipid composition in the hippocampal dentate gyrus and affect spatial cognitive flexibility in male rats.

There is growing evidence that lipids play a fundamental role in neuronal plasticity and learning and memory. Effects of nutrition on brain lipid composition and neuronal functioning are known, but the feeding interventions are often severe and may not reflect nutritional effects below clinical relevance. Therefore, we tested two commercially available rat feeding diets with only moderate differences in the food compositions, a standard diet (gross energy metabolizable 12.8 MJ/kg) and a energy reduced diet (gross energy metabolizable 8.9 MJ/kg) on possible effects upon dentate gyrus lipid composition, spatial learning and memory in a water maze and corticosterone release (blood serum concentrations) in adult male rats. Rats were fed with the standard diet up to an age of 8 weeks. One group was further fed with the standard and another with the energy reduced diet until an age of 5 months. We did not found differences in serum corticosterone levels. We found group differences in a variety of lipids in the hippocampal dentate gyrus.. Most of the lipid levels were lower in energy reduced diets, namely glycerophosphoethanolamines, sphingomyelins and hexosyceramides, whereas some ceramides (Cer18:0 and Cer24:1) and glycerophosphocholines (PC34:3 and PC36:2) were upregulated compared to the standard diet group. The performance in a common reference memory water maze task was not different between groups, however during reversal learning (platform in a different position) after the initial training, the standard diet fed rats learned better and spatial memory was improved compared to the energy reduced diet group. Thus, moderate differences in feeding diets have effects specifically upon spatial cognitive flexibility. Possible relations between differences in lipid composition and cognitive flexibility are discussed.

Mechanisms of weight regain after weight loss - the role of adipose tissue.

One of the biggest challenges in the management of obesity is the prevention of weight regain after successful weight loss. Weight regain after weight loss has large interindividual variation. Although many factors probably contribute to this variation, we hypothesize that variability in biological responses associated with weight loss-induced shrinking of subcutaneous adipocytes has an important role. In this Review, we show that weight loss-induced variations in cellular stress, extracellular matrix remodelling, inflammatory responses, adipokine secretion and lipolysis seem to be associated with the amount of weight that is regained after successful weight loss. Weight regain could therefore, at least in part, depend on a combination of these factors. Further research on the causality of these associations could aid the development of effective strategies to prevent weight regain after successful weight loss.

The effect of fasting or calorie restriction on autophagy induction: A review of the literature.

Autophagy is a lysosomal degradation process and protective housekeeping mechanism to eliminate damaged organelles, long-lived misfolded proteins and invading pathogens. Autophagy functions to recycle building blocks and energy for cellular renovation and homeostasis, allowing cells to adapt to stress. Modulation of autophagy is a potential therapeutic target for a diverse range of diseases, including metabolic conditions, neurodegenerative diseases, cancers and infectious diseases. Traditionally, food deprivation and calorie restriction (CR) have been considered to slow aging and increase longevity. Since autophagy inhibition attenuates the anti-aging effects of CR, it has been proposed that autophagy plays a substantive role in CR-mediated longevity. Among several stress stimuli inducers of autophagy, fasting and CR are the most potent non-genetic autophagy stimulators, and lack the undesirable side effects associated with alternative interventions. Despite the importance of autophagy, the evidence connecting fasting or CR with autophagy promotion has not previously been reviewed. Therefore, our objective was to weigh the evidence relating the effect of CR or fasting on autophagy promotion. We conclude that both fasting and CR have a role in the upregulation of autophagy, the evidence overwhelmingly suggesting that autophagy is induced in a wide variety of tissues and organs in response to food deprivation.

Bone metabolic responses to low energy availability achieved by diet or exercise in active eumenorrheic women.

PURPOSE: We aimed to explore the effects of low energy availability (EA)[15 kcal·kg lean body mass (LBM)-1·d-1] achieved by diet or exercise on bone turnover markers in active, eumenorrheic women. METHODS: By using a crossover design, ten eumenorrheic women (VO2 peak: 48.1 ±â€¯3.3 ml·kg-1·min-1) completed all three, 3-day conditions in a randomised order: controlled EA (CON; 45 kcal·kgLBM-1·d-1), low EA through dietary energy restriction (D-RES; 15 kcal·kgLBM-1·d-1) and low EA through increasing exercise energy expenditure (E-RES; 15 kcal·kgLBM-1·d-1), during the follicular phase of three menstrual cycles. In CON, D-RES and E-RES, participants consumed diets providing 45, 15 and 45 kcal·kgLBM-1·d-1. In E-RES only, participants completed supervised running sessions (129 ±â€¯10 min·d-1) at 70% of their VO2 peak that resulted in an exercise energy expenditure of 30 kcal·kg LBM-1·d-1. Blood samples were collected at baseline (BASE) and at the end of the 3-day period (D6) and analysed for bone turnover markers (ß-CTX and P1NP), markers of calcium metabolism (PTH, albumin-adjusted Ca, Mg and PO4) and hormones (IGF-1, T3, insulin, leptin and 17ß-oestradiol). RESULTS: In D-RES, P1NP concentrations at D6 decreased by 17% (BASE: 54.8 ±â€¯12.7 µg·L-1, D6: 45.2 ±â€¯9.3 µg·L-1, P < 0.001, d = 0.91) and were lower than D6 concentrations in CON (D6: 52.5 ±â€¯11.9 µg·L-1, P = 0.001). P1NP did not change significantly in E-RES (BASE: 55.3 ±â€¯14.4 µg·L-1, D6: 50.9 ±â€¯15.8 µg·L-1, P = 0.14). ß-CTX concentrations did not change following D-RES (BASE: 0.48 ±â€¯0.18 µg·L-1, D6: 0.55 ±â€¯0.17 µg·L-1) or E-RES (BASE: 0.47 ±â€¯0.24 µg·L-1, D6: 0.49 ±â€¯0.18 µg·L-1) (condition × time interaction effect, P = 0.17). There were no significant differences in P1NP (P = 0.25) or ß-CTX (P = 0.13) responses between D-RES and E-RES. Both conditions resulted in reductions in IGF-1 (-13% and - 23% from BASE in D-RES and E-RES, both P < 0.01) and leptin (-59% and - 61% from BASE in D-RES and E-RES, both P < 0.001); T3 decreased in D-RES only (-15% from BASE, P = 0.002) and PO4 concentrations decreased in E-RES only (-9%, P = 0.03). CONCLUSIONS: Low EA achieved through dietary energy restriction resulted in a significant decrease in bone formation but no change in bone resorption, whereas low EA achieved through exercise energy expenditure did not significantly influence bone metabolism. Both low EA conditions elicited significant and similar changes in hormone concentrations.

The effect of very-low-calorie diet on mitochondrial dysfunction in subcutaneous adipose tissue and peripheral monocytes of obese subjects with type 2 diabetes mellitus.

Mitochondrial dysfunction is a potentially important player in the development of insulin resistance and type 2 diabetes mellitus (T2DM). We investigated the changes of mRNA expression of genes encoding main enzymatic complexes of mitochondrial respiratory chain in subcutaneous adipose tissue (SCAT) and peripheral monocytes (PM) of 11 subjects with simple obesity (OB), 16 obese patients with T2DM and 17 healthy lean subjects (C) before and after very low-calorie diet (VLCD) using quantitative real time PCR. At baseline in SCAT, both T2DM and OB group had decreased mRNA expression of all investigated mitochondrial genes with the exception of 2 complex I (NDUFA 12) and complex IV (COX 4/1) enzymes in OB subjects. In contrast, in PM only the expression of complex I enzymes NDUFA 12 and MT-ND5 was reduced in both T2DM and OB subjects along with decreased expression of citrate synthase (CS) in T2DM group. Additionally, T2DM subjects showed reduced activity of pyruvate dehydrogenase and complex IV in peripheral blood elements. VLCD further decreased mRNA expression of CS and complex I (NT-ND5) and II (SDHA) enzymes in SCAT and complex IV (COX4/1) and ATP synthase in PM of T2DM group, while increasing the activity of complex IV in their peripheral blood elements. We conclude that impaired mitochondrial biogenesis and decreased activity of respiratory chain enzymatic complexes was present in SCAT and PM of obese and diabetic patients. VLCD improved metabolic parameters and ameliorated mitochondrial oxidative function in peripheral blood elements of T2DM subjects but had only minor and inconsistent effect on mitochondrial gene mRNA expression in SCAT and PM.

Effects of rapid or slow body weight reduction on intramuscular protein degradation pathways during equivalent weight loss on rats.

The purpose of this study was to compare the effects of short-term fasting-induced rapid weight loss with those of slower but equivalent body weight loss induced by daily calorie restriction on muscle protein degradation pathways and muscle protein content. Male Fischer rats were subjected to either 30 % calorie restriction for 2 weeks to slowly decrease body weight (Slow) or 3-day fasting to rapidly decrease body weight by a comparable level of that of the Slow group (Rapid). The final body weights were about 15 % lower in both the Slow and Rapid groups than in the Con group (p<0.001). The total protein content and wet weight of fast-twitch plantaris muscle, but not slow-twitch soleus muscle, were significantly lower in the Rapid group compared with the control rats fed ad libitum. Substantial increases in the expression ratio of autophagosomal membrane proteins (LC3-II/-I ratio) and polyubiquitinated protein concentration, used as biomarkers of autophagy-lysosome and ubiquitin-proteasome activities, respectively, were observed in the plantaris muscle of the Rapid group. Moreover, the LC3-II/-I ratio and polyubiquitinated protein concentration were negatively correlated with the total protein content and wet weight of plantaris muscle. These results suggest that short-term fasting-induced rapid body weight loss activates autophagy-lysosome and ubiquitin-proteasome systems more strongly than calorie restriction-induced slower weight reduction, resulting in muscular atrophy in fast-twitch muscle.

Severe energy deficit upregulates leptin receptors, leptin signaling, and PTP1B in human skeletal muscle.

In obesity, leptin receptors (OBR) and leptin signaling in skeletal muscle are downregulated. To determine whether OBR and leptin signaling are upregulated with a severe energy deficit, 15 overweight men were assessed before the intervention (PRE), after 4 days of caloric restriction (3.2 kcal·kg body wt-1·day-1) in combination with prolonged exercise (CRE; 8 h walking + 45 min single-arm cranking/day) to induce an energy deficit of ~5,500 kcal/day, and following 3 days of control diet (isoenergetic) and reduced exercise (CD). During CRE, the diet consisted solely of whey protein (n = 8) or sucrose (n = 7; 0.8 g·kg body wt-1·day-1). Muscle biopsies were obtained from the exercised and the nonexercised deltoid muscles and from the vastus lateralis. From PRE to CRE, serum glucose, insulin, and leptin were reduced. OBR expression was augmented in all examined muscles associated with increased maximal fat oxidation. Compared with PRE, after CD, phospho-Tyr1141OBR, phospho-Tyr985OBR, JAK2, and phospho-Tyr1007/1008JAK2 protein expression were increased in all muscles, whereas STAT3 and phospho-Tyr705STAT3 were increased only in the arms. The expression of protein tyrosine phosphatase 1B (PTP1B) in skeletal muscle was increased by 18 and 45% after CRE and CD, respectively (P < 0.05). Suppressor of cytokine signaling 3 (SOCS3) tended to increase in the legs and decrease in the arm muscles (ANOVA interaction: P < 0.05). Myosin heavy chain I isoform was associated with OBR protein expression (r = -0.75), phospho-Tyr985OBR (r = 0.88), and phospho-Tyr705STAT3/STAT3 (r = 0.74). In summary, despite increased PTP1B expression, skeletal muscle OBR and signaling are upregulated by a severe energy deficit with greater response in the arm than in the legs likely due to SOCS3 upregulation in the leg muscles.NEW & NOTEWORTHY This study shows that the skeletal muscle leptin receptors and their corresponding signaling cascade are upregulated in response to a severe energy deficit, contributing to increase maximal fat oxidation. The responses are more prominent in the arm muscles than in the legs but partly blunted by whey protein ingestion and high volume of exercise. This occurs despite an increase of protein tyrosine phosphatase 1B protein expression, a known inhibitor of insulin and leptin signaling.

An alternatively activated macrophage marker CD163 in severely obese patients: the influence of very low-calorie diet and bariatric surgery.

CD163 is a marker of macrophages with anti-inflammatory properties and its soluble form (sCD163) is considered a prognostic predictor of several diseases including type 2 diabetes mellitus (T2DM). We explored sCD163 levels at baseline and after very low-calorie diet (VLCD) or bariatric surgery in 32 patients with obesity (20 undergoing VLCD and 12 bariatric surgery), 32 obese patients with T2DM (22 undergoing VLCD and 10 bariatric surgery), and 19 control subjects. We also assessed the changes of CD163 positive cells of monocyte-macrophage lineage in peripheral blood and subcutaneous adipose tissue (SAT) in subset of patients. Plasma sCD163 levels were increased in obese and T2DM subjects relative to control subjects (467.2+/-40.2 and 513.8+/-37.0 vs. 334.4+/-24.8 ng/ml, p=0.001) and decreased after both interventions. Obesity decreased percentage of CD163+CD14+ monocytes in peripheral blood compared to controls (78.9+/-1.48 vs. 86.2+/-1.31 %, p=0.003) and bariatric surgery decreased CD163+CD14+HLA-DR+ macrophages in SAT (19.4+/-2.32 vs. 11.3+/-0.90 %, p=0.004). Our data suggest that increased basal sCD163 levels are related to obesity and its metabolic complications. On the contrary, sCD163 or CD163 positive cell changes do not precisely reflect metabolic improvements after weight loss.

Restricción calórica, un método eficaz, sencillo y saludable para perder peso / Caloric restriction, an effective, simple and healthy way to lose weight

Introducción: El modelo de Restricción Calórica (RC) pretende reducir el total de calorías ingeridas por semana. Las dos formas más usuales de alcanzar el déficit calórico deseado (% RC) son reducir la ingesta cada día o establecer unos días intermitentes de ayuno o restricción severa, donde el impacto de la restricción es más importante, tiene menor repercusión sobre la pérdida de masa muscular, y está más facilitada la adherencia al modelo de dieta. Se propone trabajar sobre un modelo de RC cercana al 40% del contenido calórico ordinario, intercalando 3 días de restricción severa (600-800Kcal) por semana con los restantes de ingesta habitual, durante un periodo de 6 semanas. Contenido de la investigación: Dieciocho sujetos sanos y físicamente activos, siguieron una pauta de restricción calórica (34,3 ± 15,4%) durante 6 semanas, en las que mantuvieron su actividad física regular. Al inicio y al final del experimento se determinó la composición corporal por densitometria (DEXA) y se cuantificó la pérdida de peso y su distribución en los diferentes tejidos. También se valoraron las consecuencias de la dieta en parámetros hematológicos y bioquímicos. Conclusiones: Se consigue una pérdida de peso considerable, principalmente a expensas de la masa grasa (de predominio androide), con un menor efecto sobre la masa libre de grasar, y existe una buena tolerancia y adherencia a la pauta propuesta. Consideramos la RC como una buena opción para el ajuste de peso en deportistas (AU)

Introduction: The Calorie Restriction (CR) model aims to reduce the total calories eaten per week. The two most common ways to achieve the desired caloric deficit (% CR) are to reduce intake every day or to establish intermittent fasting or severe restriction days, where the impact of the restriction is more important, has less impact on the loss of mass muscle, and adherence to the diet model is more facilitated. It is proposed to work on a CR model close to 40% of the normal caloric content, intercalating 3 days of severe restriction (600-800Kcal) per week with the rest of habitual intake, over a period of 6 weeks. Content of the research: Eighteen healthy and physically active subjects followed a caloric restriction pattern (34.3 ± 15.4%) for 6 weeks, in which they maintained their regular physical activity. At the beginning and at the end of the experiment the body composition by densitometry was determined and the weight loss and its distribution in the different tissues were quantified. The consequences of diet were also evaluated in hematological and biochemical parameters. Conclusions: A considerable weight loss is achieved, mainly at the expense of the fat mass (predominantly android), with a lower effect on the fat free mass, and there is a good tolerance and adherence to the proposed pattern. We consider CR as a good option for weight adjustment in athletes (AU)

Dietary restriction suppresses apoptotic cell death, promotes Bcl-2 and Bcl-xl mRNA expression and increases the Bcl-2/Bax protein ratio in the rat cortex after cortical injury.

Traumatic brain injury (TBI) is one of the leading causes of death and disability in humans. Subsequent pathological events occurring in the brain after TBI, referred to as secondary injury, continue to damage surrounding tissue resulting in substantial neuronal loss. Using an animal model of TBI we examined the effect of dietary restriction (DR) on the neuroapoptosis and Bcl-2 family genes as the main regulators of the intrinsic apoptotic pathway. Bcl-2, Bcl-xl and Bax mRNA and protein expression in the ipsilateral cortex of adult Wistar rats exposed to DR before TBI were studied from 2 to 28 days post injury. Our results showed that DR suppressed neuroapoptosis and promoted significant upregulation of antiapoptotic Bcl-2 and Bcl-xl mRNAs in the ipsilateral cortex following injury. Expression of the proapoptotic Bax gene increased in ad libitum (AL) fed rats but remained unchanged in rats exposed to DR. Although the expression of Bcl-2, Bcl-xl and Bax proteins was changed in a similar manner in both experimental groups, DR promoted a continuous increase in the Bcl-2:Bax protein ratio throughout the recovery period. Together with our previous finding that DR mediates inhibition of the extrinsic apoptotic pathway the present work reveals that modulation of the intrinsic pathway contributes to the beneficial effect of DR in brain injury. These findings provide new insight into the effects of DR on pro-survival signaling after injury, lending further support to its neuroprotective effect.

Reduced levels of circulating 7alpha-hydroxy-dehydroepiandrosterone in treated adolescent obese patients.

Elevated levels of glucocorticoids lead to the development of obesity and metabolic syndrome. Local glucocorticoid levels are regulated through the enzyme 11beta-hydroxysteroid dehydrogenase 1 (11beta-HSD 1), an enzyme that regenerates active cortisol from inert cortisone. Increased expression of 11beta-HSD 1 in adipose tissue promotes higher body mass index (BMI), insulin resistance, hypertension, and dyslipidemia. Human 11beta-HSD 1 is also responsible for inter-conversion of 7-hydroxylate metabolites of dehydroepiandrosterone (7-OH-DHEA) to their 7-oxo-form. To better understanding the mechanism of the action, we focused on 7-OH- and 7-oxo-DHEA, and their circulating levels during the reductive treatment in adolescent obese patients. We determined plasma levels of 7alpha-OH-DHEA, 7beta-OH-DHEA, and 7-oxo-DHEA in 55 adolescent patients aged 13.04-15.67 years, BMI greater than 90th percentile. Samples were collected before and after one month of reductive therapy. Circulating levels of 7alpha-OH-DHEA decreased during the reductive therapy from 1.727 (1.614; 1.854, transformed mean with 95 % confidence interval) to 1.530 nmol/l (1.435; 1.637, p<0.05) in girls and from 1.704 (1.583; 1.842) to 1.540 nmol/l (1.435; 1.659, p<0.05) in boys. With regard to the level of 7-oxo-DHEA, a significant reduction from 1.132 (1.044; 1.231) to 0.918 nmol/l (0.844; 1.000, p<0.05) was found after the treatment, but only in boys. No significant difference in 7beta-OH-DHEA levels was observed. In conclusions, diminished levels of 7alpha-OH-DHEA indicate its possible effect on activity of 11beta-HSD 1. Further studies are necessary to clarify whether competitive substrates for 11beta-HSD 1 such as 7alpha-OH-DHEA could inhibit production of glucocorticoids and may be involved in metabolic processes leading to reduction of obesity.

Resveratrol, from experimental data to nutritional evidence: the emergence of a new food ingredient.

The polyphenol resveratrol is found notably in grapes and in a variety of medicinal plants. Recently, resveratrol has been suggested to have cardioprotective effects and to improve metabolic health by mimicking the effects of calorie restriction. Numerous animal and in vitro studies suggest that resveratrol could improve cardiovascular and metabolic health in humans. In view of this compelling preclinical evidence, several human studies investigating the effects of resveratrol on vascular and metabolic health have been initiated. Collectively, the animal, human epidemiological, and first human intervention studies support a role of resveratrol in vascular and metabolic health. This has led to the introduction of the first supplement and food products containing resveratrol and its emergence as a promising new health ingredient. Thus, supplementation with resveratrol may be included in nutritional and lifestyle programs aiming to reduce the risk of vascular and obesity-related problems.

Anti-aging molecule, Sirt1: a novel therapeutic target for diabetic nephropathy.

Caloric restriction prolongs the lifespan of many species. Therefore, investigators have researched the usefulness of caloric restriction for healthy lifespan extension. Sirt1, an NAD(+)-dependent deacetylase, was identified as a molecule necessary for caloric restriction-related anti-aging strategies. Sirt1 functions as an intracellular energy sensor to detect the concentration of NAD(+), and controls in vivo metabolic changes under caloric restriction and starvation through its deacetylase activity to many targets including histones, nuclear transcriptional factors, and enzymes. During the past decade, investigators have reported the relationship between disturbance of Sirt1 activation and the onset of aging- and obesity-associated diseases such as diabetes, cardiovascular disease and neurodegenerative disorders. Consequently, a calorie restriction-mimetic action of Sirt1 is now expected as a new therapy for these diseases. In addition, recent studies have gradually clarified the role of Sirt1 in the onset of kidney disease. Its activation may also become a new target of treatment in the patients with chronic kidney disease including diabetic nephropathy. In this article, we would like to review the role of Sirt1 in the onset of kidney disease based on previous studies, and discuss its possibility as the target of treatment in diabetic nephropathy.

Current strategies of critical care assessment and therapy of the obese patient (hypocaloric feeding): what are we doing and what do we need to do?

Two of the most challenging issues in the clinical management of the obese patient are assessing energy requirements and whether hypocaloric (permissive) underfeeding should be employed. Multiple predictive equations have been used in the literature to estimate resting metabolic rate, although no consensus has emerged regarding which prediction equation is most accurate and precise in the obese population. Hypocaloric, or permissive underfeeding, specifically refers to the intentional administration of calories that are less than predicted energy expenditure. Thus far, very few studies performed have been performed to assess the efficacy of hypocaloric feeding in the obese hospitalized patient. It is concluded that the optimal caloric intake of obese patients in the intensive care unit remains unclear given the limitation of the existing data.

Restricción dietaria y envejecimiento: ¿una cuestión de calorías? / No disponible

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