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The incidence of obesity and overweight in the world has been increasing in recent years due to poor diet and lack of physical activity; people suffering obesity and overweight, related with malnutrition due to excess, often resort to calorie restriction diets that are usually not very effective. In this context, intermittent fasting (IF) has become popular due to the possibilities for weight loss that it offers. This diet consists of alternating periods of fasting with unrestricted eating; however, its effectiveness and consequences are unknown to most users. This narrative review analyzes whether intermittent fasting contributes to the improvement of body and metabolic composition. The purpose of the review was to examine the available data on the contribution of intermittent fasting to the improvement of body and metabolic composition, in order to provide information and to define the parameters that condition safe achievement of its benefits. IF dieting triggers adaptive cell responses that cause a decrease in lipid oxidative stress markers in individuals with obesity and prediabetes. Metabolic alterations have been found to go hand in hand with the alteration of circadian rhythms; if IF contributes to this effect, it may assist in treating and preventing obesity and associated diseases. However, there are also disadvantages, such as the loss of lean muscle mass by wasting, and increased hypoglycemia(AU)
La incidencia de obesidad y sobrepeso en el mundo ha ido en aumento en los últimos años debido a la mala alimentación y la falta de actividad física; Las personas que padecen obesidad y sobrepeso, relacionadas con la desnutrición por exceso, suelen recurrir a dietas de restricción calórica que suelen ser poco efectivas. En este contexto, el ayuno intermitente (AI) se ha popularizado debido a las posibilidades de pérdida de peso que ofrece. Esta dieta consiste en alternar períodos de ayuno con alimentación sin restricciones; sin embargo, su eficacia y consecuencias son desconocidas para la mayoría de los usuarios. Esta revisión narrativa analiza si el ayuno intermitente contribuye a la mejora de la composición corporal y metabólica. El objetivo de la revisión fue examinar los datos disponibles sobre la contribución del ayuno intermitente a la mejora de la composición corporal y metabólica, con el fin de aportar información y definir los parámetros que condicionan la consecución segura de sus beneficios. Se ha encontrado que las alteraciones metabólicas van de la mano con la alteración de los ritmos circadianos; si AI contribuye a este efecto, puede ayudar a tratar y prevenir la obesidad y las enfermedades asociadas. Sin embargo, también existen desventajas, como la pérdida de masa muscular magra por atrofia y el aumento de la hipoglucemia(AU)
Subject(s)
Humans , Male , Female , Weight Loss , Overweight , Intermittent Fasting/adverse effects , Obesity , Prediabetic State , Body Composition , Deficiency Diseases , Delivery of Health Care , HypoglycemiaABSTRACT
Objective:To evaluate the effect of short-term very low-calorie restriction(VLCR) on glycemic control in overweight/obese patients with type 2 diabetes, and to explore mechanisms through identifying markers of gut microbiota.Methods:This trial was conducted in 14 adult overweight/obese patients with type 2 diabetes. They received VLCR for 9 days in the hospital(calorie intake 300-600 kcal/d). Before and after VLCR, body weight(BW), waist circumference(WC), blood pressure(BP), and heart rate(HR) were measured, and body mass index(BMI) was calculated according to their height and weight. Fasting blood glucose(FBG), 2 h postprandial blood glucose(2hPBG), fasting insulin(FINS), triglycerides(TG), total cholesterol(TC), high-density lipoprotein-cholesterol(HDL-C), and low-density lipoprotein-cholesterol(LDL-C) were determined, and yielded the homeostasis model assessment for insulin resistance(HOMA-IR). Additional lab tests such as liver and kidney function and electrolytes were performed. The estimated glomerular filtration rate(eGFR) was calculated to evaluate renal function. All data were analyzed using the SPSS Sample Power software. Feces samples were collected before and after VLCR. Fecal samples were tested for microbial diversity using 16S rDNA technology. Professional software was used to analyze the differences of gut microbiota in feces before and after VLCR.Results:After 9 days of VLCR, BW, BMI, WC, BP, HR, FBG, 2hPBG, FINS, HOMA-IR, alkaline phosphatase, TG, and blood urea nitrogen of 14 overweight/obese patients with type 2 diabetes were significantly reduced( P<0.05). No effect was seen on serum alanine aminotransferase, aspartate amino transferase, gamma glutamyl transferase, TC, HDL-C, LDL-C, creatinine, eGFR, uric acid, albumin, calcium, and phosphorus( P>0.05). The gut microbiota diversity did not differ before and after VLCR. The abundance of Bacteroidetes increased significantly, and the Firmicutes/Bacteroidetes ratio decreased from 11.79 to 4.20. Between groups analysis showed the abundance of Parabacteroides distasonis increased significantly after VLCR. Conclusion:VLCR can improve body weight and glucose and lipid metabolism in overweight/obese patients with type 2 diabetes, with no serious adverse events. Parabacteroides distasonis may be a marker of VLCR.
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This commentary was based on the paper "Calorie Restriction with or without Time-Restricted Eating in Weight Loss" (TREATY trial) published recently in N Engl J Med, with the aim to introduce the study design of TREATY trial and discuss the main findings along with its clinical applicability. This trial offers additional evidence on the time-restricted eating and provides insights for future research.
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Food deprivation can rescue obesity and overweight-induced mood disorders, and promote mood performance in normal subjects. Animal studies and clinical research have revealed the antidepressant-like effect of calorie restriction, but little is known about the mechanism of calorie restriction-induced mood modification. Previous studies have found that astrocytes modulate depressive-like behaviors. Inositol 1,4,5-trisphosphate receptor type 2 (IP3R2) is the predominant isoform in mediating astrocyte Ca
Subject(s)
Animals , Mice , Adenosine Triphosphate , Antidepressive Agents/therapeutic use , Caloric Restriction , Mice, Knockout , Prefrontal CortexABSTRACT
Food deprivation can rescue obesity and overweight-induced mood disorders, and promote mood performance in normal subjects. Animal studies and clinical research have revealed the antidepressant-like effect of calorie restriction, but little is known about the mechanism of calorie restriction-induced mood modification. Previous studies have found that astrocytes modulate depressive-like behaviors. Inositol 1,4,5-trisphosphate receptor type 2 (IP3R2) is the predominant isoform in mediating astrocyte Ca
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Resumo Fundamento A influência de intervenções não farmacológicas como restrição calórica e exercício físico sobre a saúde e prevenção de enfermidades cardíacas tem sido documentada em estudos clínicos e experimentais. Objetivo Analisar a influência da combinação entre dieta intermitente e exercício físico sobre a capacidade funcional, metabolismo glicêmico e remodelação cardíaca. Métodos Foram utilizados 60 ratos Wistar machos distribuídos em quatro grupos: Controle (C), Exercício Físico (EF), Dieta Intermitente (DI) e Exercício Físico e Dieta Intermitente (EDI). Durante 12 semanas, enquanto C e EF foram tratados diariamente com dieta comercial padrão ad libitum, DI e EDI receberam dieta similar em dias alternados com dias de jejum. Os grupos EF e EDI foram submetidos a protocolo de corrida em esteira rolante. Posteriormente, foram analisadas capacidade funcional, comportamento nutricional e metabolismo glicêmico. Além da morfologia do coração, a expressão proteica das proteínas extracellular signal-regulated kinase (ERK) e c-Jun N-terminal kinase (JNK) no coração foi avaliada por Western-blot. A análise dos resultados foi feita por meio de Two-Way ANOVA e teste de Student-Newman-Keuls. O nível de significância considerado foi de 5%. Resultados O exercício físico aumentou a capacidade funcional nos grupos EF e EDI, e acarretou fibrose cardíaca. A combinação entre dieta intermitente e exercício físico resultou em menor área sob a curva de glicemia e menores medidas de área e interstício cardíaco no EDI em relação ao EF. A expressão de proteínas ERK e JNK foi similar entre os grupos (p>0,05). Conclusões Dieta intermitente se associa com melhor tolerância glicêmica e atenua o processo de remodelação cardíaca decorrente do exercício físico. (Arq Bras Cardiol. 2020; 115(2):184-193)
Abstract Background The effects of non-pharmacological interventions such as calorie restriction and exercise training on health and prevention of cardiovascular diseases have been investigated in clinical and experimental studies. Objective To analyze the influence of intermittent fasting and exercise training on functional fitness, glycemia and cardiac remodeling. Methods Wistar rats (n=60) were randomly divided into four groups: control, exercise training (ET), intermittent fasting (IF) and exercise training plus intermittent fasting (ETI). Over 12 weeks, control and ET animals were fed daily a standard commercial diet ad libitum , while IF and ETI animals were fed every other day. In addition, the ET and ETI groups were submitted to a running protocol on a treadmill. After this period, functional fitness, nutritional parameters and blood glucose levels were analyzed. In addition to heart morphology, myocardial protein expression of extracellular signal-regulated kinase (ERK) and c-Jun N-terminal kinase (JNK) was assessed by Western-blot. The results were analyzed using two-way ANOVA and Student-Newman-Keuls test. The level of significance considered was 5%. Results Exercise training increased functional fitness in the ET and ETI groups and promoted cardiac fibrosis. The combination of intermittent fasting and exercise training resulted in a smaller area under the blood glucose curve and reduced cardiomyocyte cross-sectional area and interstitial collagen fraction in the ETI group compared to ET. ERK and JNK expression levels were similar among groups (p>0.05). Conclusions Intermittent fasting is associated with improved glucose tolerance and attenuates cardiac remodeling induced by exercise training (Arq Bras Cardiol. 2020; 115(2):184-193)
Subject(s)
Humans , Animals , Rats , Physical Conditioning, Animal , Fasting , Rats, Wistar , Ventricular Remodeling , Caloric Restriction , MyocardiumABSTRACT
Calorie restriction is one of the diet therapies for people with diabetes.Calorie restriction can reduce weight and improve glycemic control,but the long-term effects are controversial.The effects can be influenced by the degree of calorie restriction,the study duration,and the types of food used for intervention.The mechanism includes the improvement of β cell function and insulin sensitivity.The existing problems are compliance of patients,long-term effects,possible adverse effects,and the lack of high-quality studies.In this review,we introduced the current research progress of calorie restriction on glucose metabolism in patients with type 2 diabetes.
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Objective To investigate the effect of short-term very low calorie diet on the thyroid function in patients with metabolic syndrome.Method Fifty-nine patients [(23 males and 36 females,average age (38.17 ± 9.61) years] with metabolic syndrome were received very low calorie diet for 9 days in our hospital.Anthropometric and biochemical parameters were determined before and after very low calorie diet.The level of serum FT3,FT4,TSH was measured by chemiluminescent assay,and the level of serum reverse triiodothyronine (rT3) was measured by radioimmunoassay in 31 cases.Homeostasis model assessment for insulin resistance (HOMA-IR) was employed to evaluate the severity of insulin sensitivity.Results After short-term very low calorie diet,the average body weight decreased from (76.30± 19.61)kg to (71.97 ± 18.58)kg (P＜0.01);waist circumference reduced by 6.98 cm (P＜ 0.01).The blood pressure,total cholesterol,triglycerides,low density lipoprotein-cholesterol,fasting blood glucose,fasting insulin,and HOMA-IR were all reduced significantly after very low calorie diet.The serum FT3 level decreased from (5.09 ± 0.58) pmol/L to (4.52 ± 0.58) pmol/L (P＜0.01).The changes of FT4,TSH,and rT3 were without difference.The basal FT3 levels were positively correlated with basal body weight,body mass index,waist circumference (r =0.335,0.297,and 0.262 respectively,all P＜ 0.05),and negatively correlated with HbAIC,fasting blood glucose (r=-0.293,-0.268,both P＜0.05).The basal FT4 level was negatively correlated with basal fasting insulin,HOMA-IR (r =-0.284,-0.330,both P＜0.05),while the basal TSH level was positively correlated with fasting insulin and HOMA-IR (r=0.381,0.281,both P＜0.05).The basal body weight was positively correlated with waist circumference,fasting insulin,HOMA-IR,while negatively correlated with high density lipoproteincholesterol (HDL-C;r =0.899,0.382,0.305,-0.333,all P＜0.05).After very low calorie diet,there were no more significant correlations between FT3 changes and baseline body weights,waist circumferences,and fasting blood glucose levels.The variation amplitude of body weight was positively correlated with baseline weight,waist circumference,fasting insulin,HOMA-IR,and FT3 levels (r =0.564,0.494,0.307,0.245,0.384,all P＜ 0.05).Conclusions Short-term very low calorie diet decreases the serum FT3 level and improves metabolic markers in patients with metabolic syndrome.The serum FT3 level of patients with metabolic syndrome was positively associated with body weight,whereas negatively associated with HbAIC and fasting blood glucose.Moreover,FT4 level had negative correlation with HOMA-IR,but TSH level had positive correlation with HOMA-IR.Those who had higher body weights,FT3 and HOMA-IR levels,may have more profound decrease of body weight after very low calorie diet.
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A rapidly aging population in Korea has led to increased attention in the field of anti-aging medicine. The purpose of anti-aging medicine is to slow, stop, or reverse the aging process and its associated effects, such as disability and frailty. Anti-aging medicine is emerging as a growing industry, but many supplements or protocols are available that do not have scientific evidence to support their claims. In this review, the mechanisms of action and the clinical implications of anti-aging interventions were examined and explained. Calorie restriction mimetics define compounds that imitate the outcome of calorie restriction, including an activator of AMP protein kinase (metformin), inhibitor of growth hormone/insulin-like growth factor-1 axis (pegvisomant), inhibitor of mammalian target of rapamycin (rapamycin), and activator of the sirtuin pathway (resveratrol). Hormonal replacement has also been widely used in the elderly population to improve their quality of life. Manipulating healthy gut microbiota through prebiotic/probiotics or fecal microbiota transplantation has significant potential in anti-aging medicine. Vitamin D is expected to be a primary anti-aging medicine in the near future due to its numerous positive effects in the elderly population.
Subject(s)
Aged , Humans , Aging , Fecal Microbiota Transplantation , Gastrointestinal Microbiome , Hormone Replacement Therapy , Korea , Protein Kinases , Quality of Life , Sirolimus , Vitamin DABSTRACT
O objetivo deste estudo foi verificar os efeitos da restrição calórica sobre a morfologia da aorta torácica em ratos envelhecidos e, a partir dessa análise, inferir sobre a capacidade dessa intervenção em refrear as alterações histológicas observáveis no transcorrer cronológico. Foram utilizados 41 ratos Wistar machos brancos divididos em 7 grupos: controles (Co) 7, 12, 18 e 23 meses e restrição calórica (Rc) 12, 18 e 23 meses. Os ratos foram sacrificados e as aortas coletadas e fixadas em formol 10%. As peças passaram pela rotina histológica, com inclusão em parafina seguida por cortes de 6 µm, os quais foram corados pela orseína-picrosirius-hematoxilina e tricrômico de Masson. A estatística foi feita pela análise de variância de um fator (ANOVA), seguida pelo teste de Tukey para nível de significância de 5%. Os resultados revelaram menor peso corporal e menor espessura íntima-média nos grupos de restrição calórica em relação aos controles. A eficácia da restrição calórica em deter as alterações do envelhecimento somente foi evidenciada até 18 meses de idade, não diferindo entre os grupos controle e de restrição calórica. Infere-se, portanto, um limite etário para os possíveis efeitos atenuadores da restrição calórica sobre as alterações da senescências na parede arterial.
The purpose of this study was to assess the effects of the calorie restriction on thoracic aorta morphology in aged rats, and, from this analysis, infer the capacity of this intervention to reduce measurable histological changes in the course of time. It was used 41 white male Wistar rats that were separated into 7 groups: control (Co) 7, 12, 18 and 23 months and calorie restriction (Rc) 12, 18 and 23 months. The rats were sacrificed and their aortas were collected and fixed in 10% formalin. The aortas were prepared through the histological routine techniques, with inclusion in paraffin followed by cuts of 6 µm, which were stained with orcein-picrosirius-hematoxylin and Masson's trichrome. The statistic was made through analysis of variance (ANOVA) and the Tukey´s test were employed at 5% significance. The results shown lower body weight and lower intima-media thickness in the calorie restriction group compared to control groups. The effectiveness of calorie restriction in reducing the aging changes only was observed up to 18 months, with no significant difference between the control and calorie restriction groups. Therefore, it is concluded that there is an age limit for the possible attenuating effects of the calorie restriction on changes of senescence in the arterial wall.
Subject(s)
Animals , Male , Rats , Aorta, Thoracic , Aging , Caloric RestrictionABSTRACT
The life history of man is summarized as a birth-aging-disease-death. Man eventually ages and dies. How long can humans live? What is aging? Why do we age? Is aging inevitable? Can we rejuvenate? Recent researches on biological aging suggest that humans might overcome aging and rejuvenate. In this paper, we review the biologic characteristics of aging and the latest results of biological aging research, implicating that aging can be controlled, further treated, and that humans can ultimately be rejuvenated.
Subject(s)
Humans , Aging , Cellular Senescence , Population Characteristics , RejuvenationABSTRACT
Objective To explore any effect of calorie restriction on the proliferation of satellite cells in the skeletal muscles of elderly rats.Methods Twelve male C57BL rats aged 12 or 13 months were randomly divided in to an experimental group and a control group,each of 6.The control group was fed 75.09 kJ/d as normal,while the experimental group was provided with 45.05 kJ/d (60％ of normal).The intervention lasted for 15 weeks and each rat's weight was measured every week.After the intervention,limb muscle satellite cells were sorted by fluorescenceactivated cell sorting after digestion,and the cell cycle was analyzed.Western blotting was used to assess the expression of cyclin A,D1 and E.Results There was no significant difference in the average weight of the two groups before the experiment.After the 15 weeks the average weight of the experimental group had decreased significantly (to 19.5±0.4 g),and it was significantly lighter than that of the control group (31.9±0.5 g).The average percentage of the satellite cells in the G0/G1 phase had decreased significantly in the experimental group,but the percentage in the S phase had increased significantly.The expression of cyclin A and E was significantly greater in the experimental group compared with the control group,but the expression of cyclin D1 had decreased significantly.Conclusion Caloric restriction can delay the proliferation of satellite cells in the skeletal muscles of elderly mice.
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The life history of man is summarized as a birth-aging-disease-death. Man eventually ages and dies. How long can humans live? What is aging? Why do we age? Is aging inevitable? Can we rejuvenate? Recent researches on biological aging suggest that humans might overcome aging and rejuvenate. In this paper, we review the biologic characteristics of aging and the latest results of biological aging research, implicating that aging can be controlled, further treated, and that humans can ultimately be rejuvenated.
Subject(s)
Humans , Aging , Cellular Senescence , Population Characteristics , RejuvenationABSTRACT
[Summary] Lifestyle intervention is one of the important strategies for the prevention of type 2 diabetes. Recently, caloric restriction regimen has become a hot topic as one of the cornerstone of lifestyle intervention. The alternate day fasting regimen is simple, and increases the patient compliance. Both daily calorie restriction and alternate day fasting regimen can reduce body-weight significantly in pre-diabetes subjects, and reduce the visceral fat mass and the fasting insulin levels, and improve the insulin sensitivity, as well as maintain the lean mass, though the effect on fasting blood glucose was not significant. Nevertheless, the most recent studies have demonstrated that daily calorie restriction,in particular, alternate day fasting regimens can be effective in individuals with pre-diebates in order to prevent type 2 diabetes.
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There have been many reports about the anti-aging effect of traditional Chinese medicine (TCM), but the material basis and mechanism of action have not been clearly elucidated. AMP-activated protein kinase (AMPK) is the receptor of energy metabolism and its life extending effect has been confirmed in different experiments. Over expression or activation with metform in of AAK-2/AMPK has been shown to extend life expectancy in nematodes and Drosophila. The possible downstream pathways of AMPK against aging include TOR/S6k pathway, FOXOs pathway and CRTC pathway. One of the core concepts of traditional Chinese medicine is disease prevention, for which one of manifestations is to improve the body with the same source of medicine and food to achieve longevity. It is possible to activate AMPK to achieve the goal of health preservation and prolonging the life by some of the "medicine-food harmony" treatments. Our survey finds that in "medicine-food harmony" compound TCM, "invigorating the kidney deficiency and promoting blood circulation" class dominates and Salviae Miltiorrhizae Radix Rhizoma, Astragali Radix, Coptidis Rhizoma, Poria, Atractylodes Macrocephalae Rhizoma, Radix et Rhizoma Rhei, and Ginseng Radix et Rhizoma are used in high frequency. Network pharmacology analysis using ingenuity pathway analysis (IPA) software revealed that TCM-derived drugs interacting with AMPK target proteins included berberine, emodin, curcumin, resveratrol, alcohol, cordyceps, arctiin, suggesting in a certain extent the feasibility of "medicine -food homology" drugs to extend the lifespan through the AMPK pathway. Our study combines a comprehensive database query and an IPA network pharmacology analysis to identify Chinese medicine monomer and components that may activate AMPK pathway to delay aging and to discuss the potential of these medicine by improving energy metabolism to delay the aging process, based on the concept of traditional Chinese medicine "medicine-food homology".
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Neste estudo, avaliamos o efeito da restrição calórica e do treinamento resistido na massa corporal e na sensibilidade à insulina de ratas ovariectomizadas. 80 ratas fêmeas da linhagem Holtzman foram distribuídas em 8 grupos (n=10 cada): ovariectomizado (OVX), ovariectomizado com restrição calórica (OVX RC), ovariectomizado com treinamento resistido (OVX TR), ovariectomizado com restrição calórica e treinamento resistido (OVX TR+RC), Sham operado (SHAM), Sham com restrição calórica (SHAM RC), sham com treinamento resistido (SHAM TR), sham com restrição calórica e treinamento resistido (SHAM TR+RC). Após 13 semanas de intervenção, foram analisados: massa corporal, gordura corporal; concentrações sanguíneas de glicose, insulina e adiponectina; conteúdo de AKT total e fosforilada, pi3k e Glut 4 (nos tecidos adiposos subcutâneo e retroperitoneal). As ratas ovariectomizadas (OVX, OVX RC, OVX TR e OVX TR+RC) apresentaram maior massa corporal e gordura corporal quando comparadas ao grupo SHAM. As concentrações de glicose e insulina foram semelhantes em todos os grupos experimentais, porém a concentração de adiponectina foi menor nos grupos ovariectomizados (OVX, OVX RC, OVX TR e OVX TR+RC), quando comparados ao grupo SHAM. A RC e o TR aumentaram a concentração de adiponectina quando comparado ao grupo OVX. Não houve diferença entre os grupos em relação à via de sinalização da insulina nos tecidos adiposos subcutâneo e retroperitoneal. Concluímos que a ovariectomia causa aumento de massa e gordura corporal, levando à menor concentração de adiponectina, e que a RC e o TR alteram estas modificações
In this study, we evaluated the effect of calorie restriction and strength training on the body weight and insulin sensitivity of ovariectomized rats. Eighty female Holtzman rats were divided into eight groups (n=10 per group): ovariectomized (OVX), ovariectomized plus calorie restriction (OVX-CR), ovariectomized plus strength training (OVX-ST), ovariectomized plus strength training and calorie restriction (OVX-ST+CR), sham operated (SHAM), sham plus calorie restriction (SHAM-CR), sham plus strength training (SHAM-ST), and sham plus strength training and calorie restriction (SHAM-ST+CR). The following variables were analyzed after 13 weeks of intervention: body weight; body fat; blood concentrations of glucose, insulin and adiponectin; total and phosphorylated AKT content; pi3k and Glut 4 (in subcutaneous and retroperitoneal adipose tissues). Ovariectomized rats (OVX, OVX-CR, OVX-ST, and OVX-ST+CR) had a higher body weight and body fat than SHAM animals. Glucose and insulin concentrations were similar in all experimental groups, but adiponectin concentration was lower in the ovariectomized groups (OVX, OVX-CR, OVX-ST, and OVX-ST+CR) when compared to the SHAM group. Calorie restriction and ST increased the concentration of adiponectin when compared to the OVX group. There was no difference between groups in terms of insulin signaling in subcutaneous or retroperitoneal adipose tissue. We conclude that ovariectomy increases body weight and body fat, reducing adiponectin concentration, and that CR and ST alter these modifications
Subject(s)
Animals , Female , Rats , Insulin Resistance/physiology , Rats, Sprague-Dawley/classification , Caloric Restriction/adverse effects , Menopause/metabolism , Exercise , Diet, Diabetic/adverse effects , Adiponectin/pharmacology , Resistance Training/instrumentationABSTRACT
AIM:To investigate the influence of calorie restriction ( CR) on contractility and mitochondrial bi-osynthesis in different types of rat skeletal muscles .METHODS:CR rat model was set up by feeding 60%normal food in-take of control rat every day for 8 weeks.Soleus (SOL) and extensor digitorum longus (EDL) were isolated under anesthe-sia.The twitch tension, titanic tension and fatigue resistance of SOL and EDL in response to electrical stimulation were measured to reflect the contractile function of the muscles .The copy number ratio of mitochondrial gene cytochrome C oxi-dase subunit I ( COX I) to nuclear gene β-actin was determined to evaluate the mitochondrial biosynthesis .ATP content was measured to mirror mitochondrial function .RESULTS:Compared with control group , CR for 8 weeks significantly in-creased twitch tension and titanic tension of both SOL and EDL , but only improved fatigue resistance in SOL .Markedly in-crease in ATP content in both skeletal muscles by CR intervention was observed , especially in SOL .Although CR activated AMP-activated protein kinase (AMPK) in both 2 muscles, up-regulation of mitochondrial biosynthesis and transcription of mitochondrial regulatory genes peroxisome proliferator-activated receptor γcoactivator 1α( PGC-1α) and nuclear respirato-ry factor ( NRF) was only observed in SOL .CONCLUSION:CR for 8 weeks enhanced the contractility of both rat SOL and EDL in response to electrical stimulation , especially in SOL composed of slow-twitch fibers.The mechanisms may be related to the activation of AMPK and the promotion of mitochondrial biosynthesis in SOL .
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Calorie restriction has been in use since 1900s as a therapy for obesity and type 2 diabetes. There are many modifications and progress in the forms, indications, effects, and safety of calorie restriction following a history over 100 years. However, controversies also arise such as the effect between intermittent calorie restriction vs daily calorie restriction, low fat diet vs low carbohydrate diet and low calorie diet. Therefore, more evidence-based data from high quality studies as RCT trials are needed for determining the optimal individualized calorie restriction regimen. Furthermore, calorie restriction mimetics is recently becoming an exciting research field for scientists and companies.
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Calorie restriction refers to a dietary regimen low in calories without malnutrition.During the recent 70 years,the benefit of calorie restriction regimen has been explored extensively.Work in widely diverse species,from model organism to rodents even human beings,has demonstrated that calorie restriction is an effective nutritional intervention for retarding aging and preventing chronic diseases.
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Objective To explore the effect of low calorie metabolism on the survival of HeLa cells exposed to X-rays,and the influence of starvation on the antioxidative factors in the blood of rats after irradiation.Methods MTT method was used to evaluate the impact of different concentration glucose on the proliferation of HeLa cells.Colony formation assay was employed to detect the influence of glucose ( 1,5,10 and 25 mmol/L) on radiosensitivity of HeLa cells. Flow cytometry assay was used to analyze distribution of cell cycle and apoptosis.60 male SD rats were randomly divided into 6 groups with 10 rats each.Rats in every two groups were fed ad libitum,fasted for 24 h and fasted for 48 h,respectively.Rats in one group of each approach were respectively exposed to whole-body X-rays at 11 Gy. At 2 h after irradiation,all of rats were sacrificed and their venous blood was collected.Elisa kits were used to detect superoxide dismutase (SOD) and total antioxidant capacity (T-AOC).Results An increased viability was observed in HeLa cells treated with the glucose at low concentration ( ＜25 mmol/L),while HeLa cell growth was inhibited by glucose at doses of ＞25 mmol/L. Relevant to cells treated with 1 mmoL/L glucose,SERs (sensitive enhancement ratio) in cells exposed to 5,10 and 25 mmol/L glucose were 1.07,1.10 and 1.23,respectively. A reduction of G2/M and S arrests and apeptosis caused by 6 Gy X-ray irradiation were observed [(49.68 ±1.88)％ and (35.54±1.45)％ at G2/M phase,(16.88 ±1.22)％ and (10.23 ±1.65)％ atS phase,t=10.42,5.61,P＜0.05]and in the cells treated with 1 mmol/L glucose compared with cells treated with 25 mmol/L glucose [ ( 25.50 ± 0.95 ) ％ and (7.56 ± 1.07 ) ％,t =21.72,P ＜0.05 ].Without irradiation,calorie restriction exhibited a negligible influence on SOD and T-AOC in rats.However,after 11 Gy irradiation,compared with rats fed ad libitum,the levels of SOD and T-AOC were significantly increased in rats with calorie restriction ( t =40.32,42.78, P ＜ 0.05 ).Conclusions Calorie restriction has a certain radioprotective effect in vivo and in vitro.