Project description:With the population of older and overweight individuals on the rise in the Western world, there is an ever greater need to slow the aging processes and reduce the burden of age-associated chronic disease that would significantly improve the quality of human life and reduce economic costs. Caloric restriction (CR), is the most robust and reproducible intervention known to delay aging and to improve healthspan and lifespan across species (1); however, whether this intervention can extend lifespan in humans is still unknown. Here we report that rats and humans exhibit similar responses to long-term CR at both the physiological and molecular levels. CR induced broad phenotypic similarities in both species such as reduced body weight, reduced fat mass and increased the ratio of muscle to fat. Likewise, CR evoked similar species-independent responses in the transcriptional profiles of skeletal muscle. This common signature consisted of three key pathways typically associated with improved health and survival: IGF-1/insulin signaling, mitochondrial biogenesis and inflammation. To our knowledge, these are the first results to demonstrate that long-term CR induces a similar transcriptional profile in two very divergent species, suggesting that such similarities may also translate to lifespan-extending effects in humans as is known to occur in rodents. These findings provide insight into the shared molecular mechanisms elicited by CR and highlight promising pathways for therapeutic targets to combat age-related diseases and promote longevity in humans. Male Fisher 344 rats (n=54) were randomly assigned to two groups at 2 months of age. One group was kept ad libitum (AL) fed throughout their lifespan while the calorie restriction (CR) group was progressively brought down to a 40% CR. All animals were fed a NIH-31 standard chow (Harlan Teklad, Indianapolis, IN, USA). Rats were singly housed in an environmentally controlled vivarium with unlimited access to water and a controlled photoperiod (12 hr. light;12 hr. dark). Body weights and food intake were recorded biweekly. All rats were maintained between 68-72M-BM-0F according to animal protocols and NIH guidelines. Total RNA was extracted from the vastus lateralis skeletal muscle using Trizol Reagent (Invitrogen, Carlsbad, CA) following the manufacturerM-bM-^@M-^Ys instructions, n=5 from each group. Total RNA samples were biotin labeled and hybridized to RatRef-12 v1 Gene Expression beadchips (Illumina, San Diego, CA) following Illumina protocols. Arrays were washed and scanned using an Illumina BeadArray 500GX reader. Microarray florescent signals were extracted using the Illumina GenomeStudio Gene Expression software(v1.6.0) and any spots at or below the background were filtered using an Illumina detection p-value of 0.02 and above. The natural log of all remaining scores were used to find the avg and std of each array and the z-score normalization was calculated . Correlation analysis, sample clustering analysis and principal component analysis include all of probes are performed to identify/exclude any possible outliners. The resulting dataset was next analyzed with DIANE 6.0, a spreadsheet based microarray analysis program. Gene set enrichment analysis use gene expression values or gene expression change values for all of the genes in the microarray. Parametric analysis of gene set enrichment (PAGE) was used [pubmed 20682848] for gene set analysis. Gene Sets include the MSIG database [Link], Gene Ontology Database [Link], GAD human disease and mouse phenotype gene sets [pubmed: 20092628] were used to explore functional level changes.

Project description:With the population of older and overweight individuals on the rise in the Western world, there is an ever greater need to slow the aging processes and reduce the burden of age-associated chronic disease that would significantly improve the quality of human life and reduce economic costs. Caloric restriction (CR), is the most robust and reproducible intervention known to delay aging and to improve healthspan and lifespan across species (1); however, whether this intervention can extend lifespan in humans is still unknown. Here we report that rats and humans exhibit similar responses to long-term CR at both the physiological and molecular levels. CR induced broad phenotypic similarities in both species such as reduced body weight, reduced fat mass and increased the ratio of muscle to fat. Likewise, CR evoked similar species-independent responses in the transcriptional profiles of skeletal muscle. This common signature consisted of three key pathways typically associated with improved health and survival: IGF-1/insulin signaling, mitochondrial biogenesis and inflammation. To our knowledge, these are the first results to demonstrate that long-term CR induces a similar transcriptional profile in two very divergent species, suggesting that such similarities may also translate to lifespan-extending effects in humans as is known to occur in rodents. These findings provide insight into the shared molecular mechanisms elicited by CR and highlight promising pathways for therapeutic targets to combat age-related diseases and promote longevity in humans. Percutaneous biopsy specimens of vastus lateralis muscle were taken from 15 Human subjects from a group of middle-aged (58.7±7.4 yrs.), weight-stable members of the Calorie Restriction Society who have been practicing ~30% CR with adequate nutrition (at least 100% of RDI for each nutrient) for an average of 9.6 years and 10 age matched controls that were eating a typical Western diet. Total RNA was extracted from the skeletal muscle using Trizol Reagent (Invitrogen, Carlsbad, CA) following the manufacturer’s instructions, RNA quality and quantity was checked using an Agilent 2100 Bio-analyzer and the RNA 6000 nano-chips (Agilent Technologies, Palo Alto, CA). Total RNA samples were biotin labeled and hybridized to Sentrix Human HT-12, v3 Expression BeadChips (Illumina, San Diego, CA), following Illumina protocols. Arrays were washed, stained and scanned using an Illumina BeadArray 500GX reader. Microarray florescent signals were extracted using the Illumina GenomeStudio Gene Expression software(v1.6.0) and any spots at or below the background were filtered using an Illumina detection p-value of 0.02 and above. The natural log of all remaining scores were used to find the avg and std of each array and the z-score normalization was calculated . Correlation analysis, sample clustering analysis and principal component analysis include all of probes are performed to identify/exclude any possible outliners. The resulting dataset was next analyzed with DIANE 6.0, a spreadsheet based microarray analysis program. Gene set enrichment analysis use gene expression values or gene expression change values for all of the genes in the microarray. Parametric analysis of gene set enrichment (PAGE) was used [pubmed 20682848] for gene set analysis.

Project description:Background:Mathematical models have been developed to predict body weight (BW) and composition changes in response to lifestyle interventions, but these models have not been adequately validated over the long term. Objective:We compared mathematical models of human BW dynamics underlying 2 popular web-based weight-loss prediction tools, the National Institutes of Health Body Weight Planner (NIH BWP) and the Pennington Biomedical Research Center Weight Loss Predictor (PBRC WLP), with data from the 2-year Comprehensive Assessment of Long-term Effects of Reducing Intake of Energy (CALERIE) study. Design:Mathematical models were initialized using baseline CALERIE data, and changes in body weight (?BW), fat mass (?FM), and energy expenditure (?EE) were simulated in response to time-varying changes in energy intake (?EI) objectively measured using the intake-balance method. No model parameters were adjusted from their previously published values. Results:The PBRC WLP model simulated an exaggerated early decrease in EE in response to calorie restriction, resulting in substantial underestimation of the observed mean (95% CI) BW losses by 3.8 (3.5, 4.2) kg. The NIH WLP simulations were much closer to the data, with an overall mean ?BW bias of -0.47 (-0.92, -0.015) kg. Linearized model analysis revealed that the main reason for the PBRC WLP model bias was a parameter value defining how spontaneous physical activity expenditure decreased with caloric restriction. Both models exhibited substantial variability in their ability to simulate individual results in response to calorie restriction. Monte Carlo simulations demonstrated that ?EI measurement uncertainties were a major contributor to the individual variability in NIH BWP model simulations. Conclusions:The NIH BWP outperformed the PBRC WLP and accurately simulated average weight-loss and energy balance dynamics in response to long-term calorie restriction. However, the substantial variability in the NIH BWP model predictions at the individual level suggests cautious interpretation of individual-level simulations. This trial was registered at clinicaltrials.gov as NCT00427193.

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Comparison of the long-term effects of calorie restriction without malnutrition on global gene expression profiles of rat and human skeletal muscle

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